/* -*- Mode: C; tab-width: 4 -*- * * Copyright (c) 2002-2017 Apple Inc. All rights reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * This code is completely 100% portable C. It does not depend on any external header files * from outside the mDNS project -- all the types it expects to find are defined right here. * * The previous point is very important: This file does not depend on any external * header files. It should compile on *any* platform that has a C compiler, without * making *any* assumptions about availability of so-called "standard" C functions, * routines, or types (which may or may not be present on any given platform). */ #include "DNSCommon.h" // Defines general DNS utility routines #include "uDNS.h" // Defines entry points into unicast-specific routines #include "nsec.h" #include "dnssec.h" #include "anonymous.h" // Disable certain benign warnings with Microsoft compilers #if (defined(_MSC_VER)) // Disable "conditional expression is constant" warning for debug macros. // Otherwise, this generates warnings for the perfectly natural construct "while(1)" // If someone knows a variant way of writing "while(1)" that doesn't generate warning messages, please let us know #pragma warning(disable:4127) // Disable "assignment within conditional expression". // Other compilers understand the convention that if you place the assignment expression within an extra pair // of parentheses, this signals to the compiler that you really intended an assignment and no warning is necessary. // The Microsoft compiler doesn't understand this convention, so in the absense of any other way to signal // to the compiler that the assignment is intentional, we have to just turn this warning off completely. #pragma warning(disable:4706) #endif #include "dns_sd.h" // for kDNSServiceFlags* definitions #include "dns_sd_internal.h" #define IID(a) ((int32_t)(intptr_t)(a)) #if APPLE_OSX_mDNSResponder #include // Delay in seconds before disabling multicast after there are no active queries or registrations. #define BONJOUR_DISABLE_DELAY 60 #if !NO_WCF WCFConnection *WCFConnectionNew(void) __attribute__((weak_import)); void WCFConnectionDealloc(WCFConnection* c) __attribute__((weak_import)); // Do we really need to define a macro for "if"? #define CHECK_WCF_FUNCTION(X) if (X) #endif // ! NO_WCF #else #define NO_WCF 1 #endif // APPLE_OSX_mDNSResponder #if AWD_METRICS #include "Metrics.h" #endif #if USE_DNS64 #include "DNS64.h" #endif #ifdef UNIT_TEST #include "unittest.h" #endif // Forward declarations mDNSlocal void BeginSleepProcessing(mDNS *const m); mDNSlocal void RetrySPSRegistrations(mDNS *const m); mDNSlocal void SendWakeup(mDNS *const m, mDNSInterfaceID InterfaceID, mDNSEthAddr *EthAddr, mDNSOpaque48 *password, mDNSBool unicastOnly); mDNSlocal mDNSBool LocalRecordRmvEventsForQuestion(mDNS *const m, DNSQuestion *q); mDNSlocal void mDNS_PurgeForQuestion(mDNS *const m, DNSQuestion *q); mDNSlocal void CheckForDNSSECRecords(mDNS *const m, DNSQuestion *q); mDNSlocal void mDNS_SendKeepalives(mDNS *const m); mDNSlocal void mDNS_ExtractKeepaliveInfo(AuthRecord *ar, mDNSu32 *timeout, mDNSAddr *laddr, mDNSAddr *raddr, mDNSEthAddr *eth, mDNSu32 *seq, mDNSu32 *ack, mDNSIPPort *lport, mDNSIPPort *rport, mDNSu16 *win); mDNSlocal void AdvertiseAllInterfaceRecords(mDNS *const m); mDNSlocal void DeadvertiseAllInterfaceRecords(mDNS *const m); mDNSlocal void FreeNSECRecords(mDNS *const m, CacheRecord *NSECRecords); mDNSlocal void mDNSParseNSEC3Records(mDNS *const m, const DNSMessage *const response, const mDNSu8 *end, const mDNSInterfaceID InterfaceID, CacheRecord **NSEC3Records); mDNSlocal mDNSu8 *GetValueForMACAddr(mDNSu8 *ptr, mDNSu8 *limit, mDNSEthAddr *eth); // *************************************************************************** #if COMPILER_LIKES_PRAGMA_MARK #pragma mark - Program Constants #endif // To Turn OFF mDNS_Tracer set MDNS_TRACER to 0 or undef it #define MDNS_TRACER 1 #define NO_HINFO 1 // Any records bigger than this are considered 'large' records #define SmallRecordLimit 1024 #define kMaxUpdateCredits 10 #define kUpdateCreditRefreshInterval (mDNSPlatformOneSecond * 6) // define special NR_AnswerTo values #define NR_AnswerMulticast (mDNSu8*)~0 #define NR_AnswerUnicast (mDNSu8*)~1 // Question default timeout values #define DEFAULT_MCAST_TIMEOUT 5 #define DEFAULT_LO_OR_P2P_TIMEOUT 5 // The code (see SendQueries() and BuildQuestion()) needs to have the // RequestUnicast value set to a value one greater than the number of times you want the query // sent with the "request unicast response" (QU) bit set. #define SET_QU_IN_FIRST_QUERY 2 #define kDefaultRequestUnicastCount SET_QU_IN_FIRST_QUERY // The time needed to offload records to a sleep proxy after powerd sends the kIOMessageSystemWillSleep notification #define DARK_WAKE_DELAY_SLEEP 5 #define kDarkWakeDelaySleep (mDNSPlatformOneSecond * DARK_WAKE_DELAY_SLEEP) // The maximum number of times we delay probing to prevent spurious conflicts due to stale packets #define MAX_CONFLICT_PROCESSING_DELAYS 3 // RFC 6762 defines Passive Observation Of Failures (POOF) // // A host observes the multicast queries issued by the other hosts on // the network. One of the major benefits of also sending responses // using multicast is that it allows all hosts to see the responses // (or lack thereof) to those queries. // // If a host sees queries, for which a record in its cache would be // expected to be given as an answer in a multicast response, but no // such answer is seen, then the host may take this as an indication // that the record may no longer be valid. // // After seeing two or more of these queries, and seeing no multicast // response containing the expected answer within ten seconds, then even // though its TTL may indicate that it is not yet due to expire, that // record SHOULD be flushed from the cache. // // #define POOF_ENABLED 1 mDNSexport const char *const mDNS_DomainTypeNames[] = { "b._dns-sd._udp.", // Browse "db._dns-sd._udp.", // Default Browse "lb._dns-sd._udp.", // Automatic Browse "r._dns-sd._udp.", // Registration "dr._dns-sd._udp." // Default Registration }; #ifdef UNICAST_DISABLED #define uDNS_IsActiveQuery(q, u) mDNSfalse #endif // *************************************************************************** #if COMPILER_LIKES_PRAGMA_MARK #pragma mark - #pragma mark - General Utility Functions #endif // Returns true if this is a unique, authoritative LocalOnly record that answers questions of type // A, AAAA , CNAME, or PTR. The caller should answer the question with this record and not send out // the question on the wire if LocalOnlyRecordAnswersQuestion() also returns true. // Main use is to handle /etc/hosts records and the LocalOnly PTR records created for localhost. #define UniqueLocalOnlyRecord(rr) ((rr)->ARType == AuthRecordLocalOnly && \ (rr)->resrec.RecordType & kDNSRecordTypeUniqueMask && \ ((rr)->resrec.rrtype == kDNSType_A || (rr)->resrec.rrtype == kDNSType_AAAA || \ (rr)->resrec.rrtype == kDNSType_CNAME || \ (rr)->resrec.rrtype == kDNSType_PTR)) mDNSlocal void SetNextQueryStopTime(mDNS *const m, const DNSQuestion *const q) { mDNS_CheckLock(m); if (m->NextScheduledStopTime - q->StopTime > 0) m->NextScheduledStopTime = q->StopTime; } mDNSexport void SetNextQueryTime(mDNS *const m, const DNSQuestion *const q) { mDNS_CheckLock(m); if (ActiveQuestion(q)) { // Depending on whether this is a multicast or unicast question we want to set either: // m->NextScheduledQuery = NextQSendTime(q) or // m->NextuDNSEvent = NextQSendTime(q) mDNSs32 *const timer = mDNSOpaque16IsZero(q->TargetQID) ? &m->NextScheduledQuery : &m->NextuDNSEvent; if (*timer - NextQSendTime(q) > 0) *timer = NextQSendTime(q); } } mDNSlocal void ReleaseAuthEntity(AuthHash *r, AuthEntity *e) { #if APPLE_OSX_mDNSResponder && MACOSX_MDNS_MALLOC_DEBUGGING >= 1 unsigned int i; for (i=0; inext = r->rrauth_free; r->rrauth_free = e; r->rrauth_totalused--; } mDNSlocal void ReleaseAuthGroup(AuthHash *r, AuthGroup **cp) { AuthEntity *e = (AuthEntity *)(*cp); LogMsg("ReleaseAuthGroup: Releasing AuthGroup %##s", (*cp)->name->c); if ((*cp)->rrauth_tail != &(*cp)->members) LogMsg("ERROR: (*cp)->members == mDNSNULL but (*cp)->rrauth_tail != &(*cp)->members)"); if ((*cp)->name != (domainname*)((*cp)->namestorage)) mDNSPlatformMemFree((*cp)->name); (*cp)->name = mDNSNULL; *cp = (*cp)->next; // Cut record from list ReleaseAuthEntity(r, e); } mDNSlocal AuthEntity *GetAuthEntity(AuthHash *r, const AuthGroup *const PreserveAG) { AuthEntity *e = mDNSNULL; if (r->rrauth_lock) { LogMsg("GetFreeCacheRR ERROR! Cache already locked!"); return(mDNSNULL); } r->rrauth_lock = 1; if (!r->rrauth_free) { // We allocate just one AuthEntity at a time because we need to be able // free them all individually which normally happens when we parse /etc/hosts into // AuthHash where we add the "new" entries and discard (free) the already added // entries. If we allocate as chunks, we can't free them individually. AuthEntity *storage = mDNSPlatformMemAllocate(sizeof(AuthEntity)); storage->next = mDNSNULL; r->rrauth_free = storage; } // If we still have no free records, recycle all the records we can. // Enumerating the entire auth is moderately expensive, so when we do it, we reclaim all the records we can in one pass. if (!r->rrauth_free) { mDNSu32 oldtotalused = r->rrauth_totalused; mDNSu32 slot; for (slot = 0; slot < AUTH_HASH_SLOTS; slot++) { AuthGroup **cp = &r->rrauth_hash[slot]; while (*cp) { if ((*cp)->members || (*cp)==PreserveAG) cp=&(*cp)->next; else ReleaseAuthGroup(r, cp); } } LogInfo("GetAuthEntity: Recycled %d records to reduce auth cache from %d to %d", oldtotalused - r->rrauth_totalused, oldtotalused, r->rrauth_totalused); } if (r->rrauth_free) // If there are records in the free list, take one { e = r->rrauth_free; r->rrauth_free = e->next; if (++r->rrauth_totalused >= r->rrauth_report) { LogInfo("RR Auth now using %ld objects", r->rrauth_totalused); if (r->rrauth_report < 100) r->rrauth_report += 10; else if (r->rrauth_report < 1000) r->rrauth_report += 100; else r->rrauth_report += 1000; } mDNSPlatformMemZero(e, sizeof(*e)); } r->rrauth_lock = 0; return(e); } mDNSexport AuthGroup *AuthGroupForName(AuthHash *r, const mDNSu32 namehash, const domainname *const name) { AuthGroup *ag; const mDNSu32 slot = namehash % AUTH_HASH_SLOTS; for (ag = r->rrauth_hash[slot]; ag; ag=ag->next) if (ag->namehash == namehash && SameDomainName(ag->name, name)) break; return(ag); } mDNSexport AuthGroup *AuthGroupForRecord(AuthHash *r, const ResourceRecord *const rr) { return(AuthGroupForName(r, rr->namehash, rr->name)); } mDNSlocal AuthGroup *GetAuthGroup(AuthHash *r, const ResourceRecord *const rr) { mDNSu16 namelen = DomainNameLength(rr->name); AuthGroup *ag = (AuthGroup*)GetAuthEntity(r, mDNSNULL); const mDNSu32 slot = rr->namehash % AUTH_HASH_SLOTS; if (!ag) { LogMsg("GetAuthGroup: Failed to allocate memory for %##s", rr->name->c); return(mDNSNULL); } ag->next = r->rrauth_hash[slot]; ag->namehash = rr->namehash; ag->members = mDNSNULL; ag->rrauth_tail = &ag->members; ag->NewLocalOnlyRecords = mDNSNULL; if (namelen > sizeof(ag->namestorage)) ag->name = mDNSPlatformMemAllocate(namelen); else ag->name = (domainname*)ag->namestorage; if (!ag->name) { LogMsg("GetAuthGroup: Failed to allocate name storage for %##s", rr->name->c); ReleaseAuthEntity(r, (AuthEntity*)ag); return(mDNSNULL); } AssignDomainName(ag->name, rr->name); if (AuthGroupForRecord(r, rr)) LogMsg("GetAuthGroup: Already have AuthGroup for %##s", rr->name->c); r->rrauth_hash[slot] = ag; if (AuthGroupForRecord(r, rr) != ag) LogMsg("GetAuthGroup: Not finding AuthGroup for %##s", rr->name->c); return(ag); } // Returns the AuthGroup in which the AuthRecord was inserted mDNSexport AuthGroup *InsertAuthRecord(mDNS *const m, AuthHash *r, AuthRecord *rr) { AuthGroup *ag; (void)m; ag = AuthGroupForRecord(r, &rr->resrec); if (!ag) ag = GetAuthGroup(r, &rr->resrec); // If we don't have a AuthGroup for this name, make one now if (ag) { *(ag->rrauth_tail) = rr; // Append this record to tail of cache slot list ag->rrauth_tail = &(rr->next); // Advance tail pointer } return ag; } mDNSexport AuthGroup *RemoveAuthRecord(mDNS *const m, AuthHash *r, AuthRecord *rr) { AuthGroup *a; AuthRecord **rp; a = AuthGroupForRecord(r, &rr->resrec); if (!a) { LogMsg("RemoveAuthRecord: ERROR!! AuthGroup not found for %s", ARDisplayString(m, rr)); return mDNSNULL; } rp = &a->members; while (*rp) { if (*rp != rr) rp=&(*rp)->next; else { // We don't break here, so that we can set the tail below without tracking "prev" pointers LogInfo("RemoveAuthRecord: removing auth record %s from table", ARDisplayString(m, rr)); *rp = (*rp)->next; // Cut record from list } } // TBD: If there are no more members, release authgroup ? a->rrauth_tail = rp; return a; } mDNSexport CacheGroup *CacheGroupForName(const mDNS *const m, const mDNSu32 namehash, const domainname *const name) { CacheGroup *cg; mDNSu32 slot = HashSlotFromNameHash(namehash); for (cg = m->rrcache_hash[slot]; cg; cg=cg->next) if (cg->namehash == namehash && SameDomainName(cg->name, name)) break; return(cg); } mDNSlocal CacheGroup *CacheGroupForRecord(const mDNS *const m, const ResourceRecord *const rr) { return(CacheGroupForName(m, rr->namehash, rr->name)); } mDNSexport mDNSBool mDNS_AddressIsLocalSubnet(mDNS *const m, const mDNSInterfaceID InterfaceID, const mDNSAddr *addr) { NetworkInterfaceInfo *intf; if (addr->type == mDNSAddrType_IPv4) { // Normally we resist touching the NotAnInteger fields, but here we're doing tricky bitwise masking so we make an exception if (mDNSv4AddressIsLinkLocal(&addr->ip.v4)) return(mDNStrue); for (intf = m->HostInterfaces; intf; intf = intf->next) if (intf->ip.type == addr->type && intf->InterfaceID == InterfaceID && intf->McastTxRx) if (((intf->ip.ip.v4.NotAnInteger ^ addr->ip.v4.NotAnInteger) & intf->mask.ip.v4.NotAnInteger) == 0) return(mDNStrue); } if (addr->type == mDNSAddrType_IPv6) { if (mDNSv6AddressIsLinkLocal(&addr->ip.v6)) return(mDNStrue); for (intf = m->HostInterfaces; intf; intf = intf->next) if (intf->ip.type == addr->type && intf->InterfaceID == InterfaceID && intf->McastTxRx) if ((((intf->ip.ip.v6.l[0] ^ addr->ip.v6.l[0]) & intf->mask.ip.v6.l[0]) == 0) && (((intf->ip.ip.v6.l[1] ^ addr->ip.v6.l[1]) & intf->mask.ip.v6.l[1]) == 0) && (((intf->ip.ip.v6.l[2] ^ addr->ip.v6.l[2]) & intf->mask.ip.v6.l[2]) == 0) && (((intf->ip.ip.v6.l[3] ^ addr->ip.v6.l[3]) & intf->mask.ip.v6.l[3]) == 0)) return(mDNStrue); } return(mDNSfalse); } mDNSlocal NetworkInterfaceInfo *FirstInterfaceForID(mDNS *const m, const mDNSInterfaceID InterfaceID) { NetworkInterfaceInfo *intf = m->HostInterfaces; while (intf && intf->InterfaceID != InterfaceID) intf = intf->next; return(intf); } mDNSlocal NetworkInterfaceInfo *FirstIPv4LLInterfaceForID(mDNS *const m, const mDNSInterfaceID InterfaceID) { NetworkInterfaceInfo *intf; if (!InterfaceID) return mDNSNULL; // Note: We don't check for InterfaceActive, as the active interface could be IPv6 and // we still want to find the first IPv4 Link-Local interface for (intf = m->HostInterfaces; intf; intf = intf->next) { if (intf->InterfaceID == InterfaceID && intf->ip.type == mDNSAddrType_IPv4 && mDNSv4AddressIsLinkLocal(&intf->ip.ip.v4)) { debugf("FirstIPv4LLInterfaceForID: found LL interface with address %.4a", &intf->ip.ip.v4); return intf; } } return (mDNSNULL); } mDNSexport char *InterfaceNameForID(mDNS *const m, const mDNSInterfaceID InterfaceID) { NetworkInterfaceInfo *intf = FirstInterfaceForID(m, InterfaceID); return(intf ? intf->ifname : mDNSNULL); } // Caller should hold the lock mDNSlocal void GenerateNegativeResponse(mDNS *const m, mDNSInterfaceID InterfaceID, QC_result qc) { DNSQuestion *q; if (!m->CurrentQuestion) { LogMsg("GenerateNegativeResponse: ERROR!! CurrentQuestion not set"); return; } q = m->CurrentQuestion; LogInfo("GenerateNegativeResponse: Generating negative response for question %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); MakeNegativeCacheRecord(m, &m->rec.r, &q->qname, q->qnamehash, q->qtype, q->qclass, 60, InterfaceID, mDNSNULL); // We need to force the response through in the following cases // // a) SuppressUnusable questions that are suppressed // b) Append search domains and retry the question // // The question may not have set Intermediates in which case we don't deliver negative responses. So, to force // through we use "QC_forceresponse". AnswerCurrentQuestionWithResourceRecord(m, &m->rec.r, qc); if (m->CurrentQuestion == q) { q->ThisQInterval = 0; } // Deactivate this question // Don't touch the question after this m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it } mDNSexport void AnswerQuestionByFollowingCNAME(mDNS *const m, DNSQuestion *q, ResourceRecord *rr) { const mDNSBool selfref = SameDomainName(&q->qname, &rr->rdata->u.name); if (q->CNAMEReferrals >= 10 || selfref) { LogMsg("AnswerQuestionByFollowingCNAME: %p %##s (%s) NOT following CNAME referral %d%s for %s", q, q->qname.c, DNSTypeName(q->qtype), q->CNAMEReferrals, selfref ? " (Self-Referential)" : "", RRDisplayString(m, rr)); } else { const mDNSu32 c = q->CNAMEReferrals + 1; // Stash a copy of the new q->CNAMEReferrals value UDPSocket *sock = q->LocalSocket; mDNSOpaque16 id = q->TargetQID; #if AWD_METRICS uDNSMetrics metrics; #endif q->LocalSocket = mDNSNULL; // The SameDomainName check above is to ignore bogus CNAME records that point right back at // themselves. Without that check we can get into a case where we have two duplicate questions, // A and B, and when we stop question A, UpdateQuestionDuplicates copies the value of CNAMEReferrals // from A to B, and then A is re-appended to the end of the list as a duplicate of B (because // the target name is still the same), and then when we stop question B, UpdateQuestionDuplicates // copies the B's value of CNAMEReferrals back to A, and we end up not incrementing CNAMEReferrals // for either of them. This is not a problem for CNAME loops of two or more records because in // those cases the newly re-appended question A has a different target name and therefore cannot be // a duplicate of any other question ('B') which was itself a duplicate of the previous question A. // Right now we just stop and re-use the existing query. If we really wanted to be 100% perfect, // and track CNAMEs coming and going, we should really create a subordinate query here, // which we would subsequently cancel and retract if the CNAME referral record were removed. // In reality this is such a corner case we'll ignore it until someone actually needs it. LogInfo("AnswerQuestionByFollowingCNAME: %p %##s (%s) following CNAME referral %d for %s", q, q->qname.c, DNSTypeName(q->qtype), q->CNAMEReferrals, RRDisplayString(m, rr)); #if AWD_METRICS if ((q->CNAMEReferrals == 0) && !q->metrics.originalQName) { domainname * qName; mDNSu16 qNameLen; qNameLen = DomainNameLength(&q->qname); if ((qNameLen > 0) && (qNameLen <= MAX_DOMAIN_NAME)) { qName = mDNSPlatformMemAllocate(qNameLen); if (qName) { mDNSPlatformMemCopy(qName->c, q->qname.c, qNameLen); q->metrics.originalQName = qName; } } } metrics = q->metrics; mDNSPlatformMemZero(&q->metrics, sizeof(q->metrics)); #endif mDNS_StopQuery_internal(m, q); // Stop old query AssignDomainName(&q->qname, &rr->rdata->u.name); // Update qname q->qnamehash = DomainNameHashValue(&q->qname); // and namehash // If a unicast query results in a CNAME that points to a .local, we need to re-try // this as unicast. Setting the mDNSInterface_Unicast tells mDNS_StartQuery_internal // to try this as unicast query even though it is a .local name if (!mDNSOpaque16IsZero(q->TargetQID) && IsLocalDomain(&q->qname)) { LogInfo("AnswerQuestionByFollowingCNAME: Resolving a .local CNAME %p %##s (%s) Record %s", q, q->qname.c, DNSTypeName(q->qtype), RRDisplayString(m, rr)); q->InterfaceID = mDNSInterface_Unicast; } mDNS_StartQuery_internal(m, q); // start new query // Record how many times we've done this. We need to do this *after* mDNS_StartQuery_internal, // because mDNS_StartQuery_internal re-initializes CNAMEReferrals to zero q->CNAMEReferrals = c; #if AWD_METRICS q->metrics = metrics; #endif if (sock) { // If our new query is a duplicate, then it can't have a socket of its own, so we have to close the one we saved. if (q->DuplicateOf) mDNSPlatformUDPClose(sock); else { // Transplant the old socket into the new question, and copy the query ID across too. // No need to close the old q->LocalSocket value because it won't have been created yet (they're made lazily on-demand). q->LocalSocket = sock; q->TargetQID = id; } } } } #ifdef USE_LIBIDN #include // #define DEBUG_PUNYCODE 1 mDNSlocal mDNSu8 *PunycodeConvert(const mDNSu8 *const src, mDNSu8 *const dst, const mDNSu8 *const end) { UErrorCode errorCode = U_ZERO_ERROR; UIDNAInfo info = UIDNA_INFO_INITIALIZER; UIDNA *uts46 = uidna_openUTS46(UIDNA_USE_STD3_RULES|UIDNA_NONTRANSITIONAL_TO_UNICODE, &errorCode); int32_t len = uidna_nameToASCII_UTF8(uts46, (const char *)src+1, src[0], (char *)dst+1, end-(dst+1), &info, &errorCode); uidna_close(uts46); #if DEBUG_PUNYCODE if (errorCode) LogMsg("uidna_nameToASCII_UTF8(%##s) failed errorCode %d", src, errorCode); if (info.errors) LogMsg("uidna_nameToASCII_UTF8(%##s) failed info.errors 0x%08X", src, info.errors); if (len > MAX_DOMAIN_LABEL) LogMsg("uidna_nameToASCII_UTF8(%##s) result too long %d", src, len); #endif if (errorCode || info.errors || len > MAX_DOMAIN_LABEL) return mDNSNULL; *dst = len; return(dst + 1 + len); } mDNSlocal mDNSBool IsHighASCIILabel(const mDNSu8 *d) { int i; for (i=1; i<=d[0]; i++) if (d[i] & 0x80) return mDNStrue; return mDNSfalse; } mDNSlocal const mDNSu8 *FindLastHighASCIILabel(const domainname *const d) { const mDNSu8 *ptr = d->c; const mDNSu8 *ans = mDNSNULL; while (ptr[0]) { const mDNSu8 *const next = ptr + 1 + ptr[0]; if (ptr[0] > MAX_DOMAIN_LABEL || next >= d->c + MAX_DOMAIN_NAME) return mDNSNULL; if (IsHighASCIILabel(ptr)) ans = ptr; ptr = next; } return ans; } mDNSlocal mDNSBool PerformNextPunycodeConversion(const DNSQuestion *const q, domainname *const newname) { const mDNSu8 *h = FindLastHighASCIILabel(&q->qname); #if DEBUG_PUNYCODE LogMsg("PerformNextPunycodeConversion: %##s (%s) Last High-ASCII Label %##s", q->qname.c, DNSTypeName(q->qtype), h); #endif if (!h) return mDNSfalse; // There are no high-ascii labels to convert mDNSu8 *const dst = PunycodeConvert(h, newname->c + (h - q->qname.c), newname->c + MAX_DOMAIN_NAME); if (!dst) return mDNSfalse; // The label was not convertible to Punycode else { // If Punycode conversion of final eligible label was successful, copy the rest of the domainname const mDNSu8 *const src = h + 1 + h[0]; const mDNSu8 remainder = DomainNameLength((domainname*)src); if (dst + remainder > newname->c + MAX_DOMAIN_NAME) return mDNSfalse; // Name too long -- cannot be converted to Punycode mDNSPlatformMemCopy(newname->c, q->qname.c, h - q->qname.c); // Fill in the leading part mDNSPlatformMemCopy(dst, src, remainder); // Fill in the trailing part #if DEBUG_PUNYCODE LogMsg("PerformNextPunycodeConversion: %##s converted to %##s", q->qname.c, newname->c); #endif return mDNStrue; } } #endif // USE_LIBIDN // For a single given DNSQuestion pointed to by CurrentQuestion, deliver an add/remove result for the single given AuthRecord // Note: All the callers should use the m->CurrentQuestion to see if the question is still valid or not mDNSlocal void AnswerLocalQuestionWithLocalAuthRecord(mDNS *const m, AuthRecord *rr, QC_result AddRecord) { DNSQuestion *q = m->CurrentQuestion; mDNSBool followcname; if (!q) { LogMsg("AnswerLocalQuestionWithLocalAuthRecord: ERROR!! CurrentQuestion NULL while answering with %s", ARDisplayString(m, rr)); return; } followcname = FollowCNAME(q, &rr->resrec, AddRecord); // We should not be delivering results for record types Unregistered, Deregistering, and (unverified) Unique if (!(rr->resrec.RecordType & kDNSRecordTypeActiveMask)) { LogMsg("AnswerLocalQuestionWithLocalAuthRecord: *NOT* delivering %s event for local record type %X %s", AddRecord ? "Add" : "Rmv", rr->resrec.RecordType, ARDisplayString(m, rr)); return; } // Indicate that we've given at least one positive answer for this record, so we should be prepared to send a goodbye for it if (AddRecord) rr->AnsweredLocalQ = mDNStrue; mDNS_DropLockBeforeCallback(); // Allow client to legally make mDNS API calls from the callback if (q->QuestionCallback && !q->NoAnswer) { q->CurrentAnswers += AddRecord ? 1 : -1; if (UniqueLocalOnlyRecord(rr)) { if (!followcname || q->ReturnIntermed) { // Don't send this packet on the wire as we answered from /etc/hosts q->ThisQInterval = 0; q->LOAddressAnswers += AddRecord ? 1 : -1; q->QuestionCallback(m, q, &rr->resrec, AddRecord); } mDNS_ReclaimLockAfterCallback(); // Decrement mDNS_reentrancy to block mDNS API calls again // The callback above could have caused the question to stop. Detect that // using m->CurrentQuestion if (followcname && m->CurrentQuestion == q) AnswerQuestionByFollowingCNAME(m, q, &rr->resrec); return; } else { q->QuestionCallback(m, q, &rr->resrec, AddRecord); } } mDNS_ReclaimLockAfterCallback(); // Decrement mDNS_reentrancy to block mDNS API calls again } mDNSlocal void AnswerInterfaceAnyQuestionsWithLocalAuthRecord(mDNS *const m, AuthRecord *rr, QC_result AddRecord) { if (m->CurrentQuestion) LogMsg("AnswerInterfaceAnyQuestionsWithLocalAuthRecord: ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = m->Questions; while (m->CurrentQuestion && m->CurrentQuestion != m->NewQuestions) { mDNSBool answered; DNSQuestion *q = m->CurrentQuestion; if (RRAny(rr)) answered = ResourceRecordAnswersQuestion(&rr->resrec, q); else answered = LocalOnlyRecordAnswersQuestion(rr, q); if (answered) AnswerLocalQuestionWithLocalAuthRecord(m, rr, AddRecord); // MUST NOT dereference q again if (m->CurrentQuestion == q) // If m->CurrentQuestion was not auto-advanced, do it ourselves now m->CurrentQuestion = q->next; } m->CurrentQuestion = mDNSNULL; } // When a new local AuthRecord is created or deleted, AnswerAllLocalQuestionsWithLocalAuthRecord() // delivers the appropriate add/remove events to listening questions: // 1. It runs though all our LocalOnlyQuestions delivering answers as appropriate, // stopping if it reaches a NewLocalOnlyQuestion -- brand-new questions are handled by AnswerNewLocalOnlyQuestion(). // 2. If the AuthRecord is marked mDNSInterface_LocalOnly or mDNSInterface_P2P, then it also runs though // our main question list, delivering answers to mDNSInterface_Any questions as appropriate, // stopping if it reaches a NewQuestion -- brand-new questions are handled by AnswerNewQuestion(). // // AnswerAllLocalQuestionsWithLocalAuthRecord is used by the m->NewLocalRecords loop in mDNS_Execute(), // and by mDNS_Deregister_internal() mDNSlocal void AnswerAllLocalQuestionsWithLocalAuthRecord(mDNS *const m, AuthRecord *rr, QC_result AddRecord) { if (m->CurrentQuestion) LogMsg("AnswerAllLocalQuestionsWithLocalAuthRecord ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = m->LocalOnlyQuestions; while (m->CurrentQuestion && m->CurrentQuestion != m->NewLocalOnlyQuestions) { mDNSBool answered; DNSQuestion *q = m->CurrentQuestion; // We are called with both LocalOnly/P2P record or a regular AuthRecord if (RRAny(rr)) answered = ResourceRecordAnswersQuestion(&rr->resrec, q); else answered = LocalOnlyRecordAnswersQuestion(rr, q); if (answered) AnswerLocalQuestionWithLocalAuthRecord(m, rr, AddRecord); // MUST NOT dereference q again if (m->CurrentQuestion == q) // If m->CurrentQuestion was not auto-advanced, do it ourselves now m->CurrentQuestion = q->next; } m->CurrentQuestion = mDNSNULL; // If this AuthRecord is marked LocalOnly or P2P, then we want to deliver it to all local 'mDNSInterface_Any' questions if (rr->ARType == AuthRecordLocalOnly || rr->ARType == AuthRecordP2P) AnswerInterfaceAnyQuestionsWithLocalAuthRecord(m, rr, AddRecord); } // *************************************************************************** #if COMPILER_LIKES_PRAGMA_MARK #pragma mark - #pragma mark - Resource Record Utility Functions #endif #define RRTypeIsAddressType(T) ((T) == kDNSType_A || (T) == kDNSType_AAAA) #define ResourceRecordIsValidAnswer(RR) ( ((RR)->resrec.RecordType & kDNSRecordTypeActiveMask) && \ ((RR)->Additional1 == mDNSNULL || ((RR)->Additional1->resrec.RecordType & kDNSRecordTypeActiveMask)) && \ ((RR)->Additional2 == mDNSNULL || ((RR)->Additional2->resrec.RecordType & kDNSRecordTypeActiveMask)) && \ ((RR)->DependentOn == mDNSNULL || ((RR)->DependentOn->resrec.RecordType & kDNSRecordTypeActiveMask)) ) #define ResourceRecordIsValidInterfaceAnswer(RR, INTID) \ (ResourceRecordIsValidAnswer(RR) && \ ((RR)->resrec.InterfaceID == mDNSInterface_Any || (RR)->resrec.InterfaceID == (INTID))) #define DefaultProbeCountForTypeUnique ((mDNSu8)3) #define DefaultProbeCountForRecordType(X) ((X) == kDNSRecordTypeUnique ? DefaultProbeCountForTypeUnique : (mDNSu8)0) // See RFC 6762: "8.3 Announcing" // "The Multicast DNS responder MUST send at least two unsolicited responses, one second apart." // Send 4, which is really 8 since we send on both IPv4 and IPv6. #define InitialAnnounceCount ((mDNSu8)4) // For goodbye packets we set the count to 3, and for wakeups we set it to 18 // (which will be up to 15 wakeup attempts over the course of 30 seconds, // and then if the machine fails to wake, 3 goodbye packets). #define GoodbyeCount ((mDNSu8)3) #define WakeupCount ((mDNSu8)18) #define MAX_PROBE_RESTARTS ((mDNSu8)20) // Number of wakeups we send if WakeOnResolve is set in the question #define InitialWakeOnResolveCount ((mDNSu8)3) // Note that the announce intervals use exponential backoff, doubling each time. The probe intervals do not. // This means that because the announce interval is doubled after sending the first packet, the first // observed on-the-wire inter-packet interval between announcements is actually one second. // The half-second value here may be thought of as a conceptual (non-existent) half-second delay *before* the first packet is sent. #define DefaultProbeIntervalForTypeUnique (mDNSPlatformOneSecond/4) #define DefaultAnnounceIntervalForTypeShared (mDNSPlatformOneSecond/2) #define DefaultAnnounceIntervalForTypeUnique (mDNSPlatformOneSecond/2) #define DefaultAPIntervalForRecordType(X) ((X) &kDNSRecordTypeActiveSharedMask ? DefaultAnnounceIntervalForTypeShared : \ (X) &kDNSRecordTypeUnique ? DefaultProbeIntervalForTypeUnique : \ (X) &kDNSRecordTypeActiveUniqueMask ? DefaultAnnounceIntervalForTypeUnique : 0) #define TimeToAnnounceThisRecord(RR,time) ((RR)->AnnounceCount && (time) - ((RR)->LastAPTime + (RR)->ThisAPInterval) >= 0) #define TicksTTL(RR) ((mDNSs32)(RR)->resrec.rroriginalttl * mDNSPlatformOneSecond) #define RRExpireTime(RR) ((RR)->TimeRcvd + TicksTTL(RR)) // Adjustment factor to avoid race condition (used for unicast cache entries) : // Suppose real record has TTL of 3600, and our local caching server has held it for 3500 seconds, so it returns an aged TTL of 100. // If we do our normal refresh at 80% of the TTL, our local caching server will return 20 seconds, so we'll do another // 80% refresh after 16 seconds, and then the server will return 4 seconds, and so on, in the fashion of Zeno's paradox. // To avoid this, we extend the record's effective TTL to give it a little extra grace period. // We adjust the 100 second TTL to 127. This means that when we do our 80% query at 102 seconds, // the cached copy at our local caching server will already have expired, so the server will be forced // to fetch a fresh copy from the authoritative server, and then return a fresh record with the full TTL of 3600 seconds. #define RRAdjustTTL(ttl) ((ttl) + ((ttl)/4) + 2) #define RRUnadjustedTTL(ttl) ((((ttl) - 2) * 4) / 5) #define MaxUnansweredQueries 4 // SameResourceRecordSignature returns true if two resources records have the same name, type, and class, and may be sent // (or were received) on the same interface (i.e. if *both* records specify an interface, then it has to match). // TTL and rdata may differ. // This is used for cache flush management: // When sending a unique record, all other records matching "SameResourceRecordSignature" must also be sent // When receiving a unique record, all old cache records matching "SameResourceRecordSignature" are flushed // SameResourceRecordNameClassInterface is functionally the same as SameResourceRecordSignature, except rrtype does not have to match #define SameResourceRecordSignature(A,B) (A)->resrec.rrtype == (B)->resrec.rrtype && SameResourceRecordNameClassInterface((A),(B)) mDNSlocal mDNSBool SameResourceRecordNameClassInterface(const AuthRecord *const r1, const AuthRecord *const r2) { if (!r1) { LogMsg("SameResourceRecordSignature ERROR: r1 is NULL"); return(mDNSfalse); } if (!r2) { LogMsg("SameResourceRecordSignature ERROR: r2 is NULL"); return(mDNSfalse); } if (r1->resrec.InterfaceID && r2->resrec.InterfaceID && r1->resrec.InterfaceID != r2->resrec.InterfaceID) return(mDNSfalse); return (mDNSBool)( r1->resrec.rrclass == r2->resrec.rrclass && r1->resrec.namehash == r2->resrec.namehash && SameDomainName(r1->resrec.name, r2->resrec.name)); } // PacketRRMatchesSignature behaves as SameResourceRecordSignature, except that types may differ if our // authoratative record is unique (as opposed to shared). For unique records, we are supposed to have // complete ownership of *all* types for this name, so *any* record type with the same name is a conflict. // In addition, when probing we send our questions with the wildcard type kDNSQType_ANY, // so a response of any type should match, even if it is not actually the type the client plans to use. // For now, to make it easier to avoid false conflicts, we treat SPS Proxy records like shared records, // and require the rrtypes to match for the rdata to be considered potentially conflicting mDNSlocal mDNSBool PacketRRMatchesSignature(const CacheRecord *const pktrr, const AuthRecord *const authrr) { if (!pktrr) { LogMsg("PacketRRMatchesSignature ERROR: pktrr is NULL"); return(mDNSfalse); } if (!authrr) { LogMsg("PacketRRMatchesSignature ERROR: authrr is NULL"); return(mDNSfalse); } if (pktrr->resrec.InterfaceID && authrr->resrec.InterfaceID && pktrr->resrec.InterfaceID != authrr->resrec.InterfaceID) return(mDNSfalse); if (!(authrr->resrec.RecordType & kDNSRecordTypeUniqueMask) || authrr->WakeUp.HMAC.l[0]) if (pktrr->resrec.rrtype != authrr->resrec.rrtype) return(mDNSfalse); if ((authrr->resrec.InterfaceID == mDNSInterface_Any) && !mDNSPlatformValidRecordForInterface(authrr, pktrr->resrec.InterfaceID)) return(mDNSfalse); return (mDNSBool)( pktrr->resrec.rrclass == authrr->resrec.rrclass && pktrr->resrec.namehash == authrr->resrec.namehash && SameDomainName(pktrr->resrec.name, authrr->resrec.name)); } // CacheRecord *ka is the CacheRecord from the known answer list in the query. // This is the information that the requester believes to be correct. // AuthRecord *rr is the answer we are proposing to give, if not suppressed. // This is the information that we believe to be correct. // We've already determined that we plan to give this answer on this interface // (either the record is non-specific, or it is specific to this interface) // so now we just need to check the name, type, class, rdata and TTL. mDNSlocal mDNSBool ShouldSuppressKnownAnswer(const CacheRecord *const ka, const AuthRecord *const rr) { // If RR signature is different, or data is different, then don't suppress our answer if (!IdenticalResourceRecord(&ka->resrec, &rr->resrec)) return(mDNSfalse); // If the requester's indicated TTL is less than half the real TTL, // we need to give our answer before the requester's copy expires. // If the requester's indicated TTL is at least half the real TTL, // then we can suppress our answer this time. // If the requester's indicated TTL is greater than the TTL we believe, // then that's okay, and we don't need to do anything about it. // (If two responders on the network are offering the same information, // that's okay, and if they are offering the information with different TTLs, // the one offering the lower TTL should defer to the one offering the higher TTL.) return (mDNSBool)(ka->resrec.rroriginalttl >= rr->resrec.rroriginalttl / 2); } mDNSlocal void SetNextAnnounceProbeTime(mDNS *const m, const AuthRecord *const rr) { if (rr->resrec.RecordType == kDNSRecordTypeUnique) { if ((rr->LastAPTime + rr->ThisAPInterval) - m->timenow > mDNSPlatformOneSecond * 10) { LogMsg("SetNextAnnounceProbeTime: ProbeCount %d Next in %d %s", rr->ProbeCount, (rr->LastAPTime + rr->ThisAPInterval) - m->timenow, ARDisplayString(m, rr)); LogMsg("SetNextAnnounceProbeTime: m->SuppressProbes %d m->timenow %d diff %d", m->SuppressProbes, m->timenow, m->SuppressProbes - m->timenow); } if (m->NextScheduledProbe - (rr->LastAPTime + rr->ThisAPInterval) >= 0) m->NextScheduledProbe = (rr->LastAPTime + rr->ThisAPInterval); // Some defensive code: // If (rr->LastAPTime + rr->ThisAPInterval) happens to be far in the past, we don't want to allow // NextScheduledProbe to be set excessively in the past, because that can cause bad things to happen. // See: mDNS: Sometimes advertising stops working and record interval is set to zero if (m->NextScheduledProbe - m->timenow < 0) m->NextScheduledProbe = m->timenow; } else if (rr->AnnounceCount && (ResourceRecordIsValidAnswer(rr) || rr->resrec.RecordType == kDNSRecordTypeDeregistering)) { if (m->NextScheduledResponse - (rr->LastAPTime + rr->ThisAPInterval) >= 0) m->NextScheduledResponse = (rr->LastAPTime + rr->ThisAPInterval); } } mDNSlocal void InitializeLastAPTime(mDNS *const m, AuthRecord *const rr) { // For reverse-mapping Sleep Proxy PTR records, probe interval is one second rr->ThisAPInterval = rr->AddressProxy.type ? mDNSPlatformOneSecond : DefaultAPIntervalForRecordType(rr->resrec.RecordType); // * If this is a record type that's going to probe, then we use the m->SuppressProbes time. // * Otherwise, if it's not going to probe, but m->SuppressProbes is set because we have other // records that are going to probe, then we delay its first announcement so that it will // go out synchronized with the first announcement for the other records that *are* probing. // This is a minor performance tweak that helps keep groups of related records synchronized together. // The addition of "interval / 2" is to make sure that, in the event that any of the probes are // delayed by a few milliseconds, this announcement does not inadvertently go out *before* the probing is complete. // When the probing is complete and those records begin to announce, these records will also be picked up and accelerated, // because they will meet the criterion of being at least half-way to their scheduled announcement time. // * If it's not going to probe and m->SuppressProbes is not already set then we should announce immediately. if (rr->ProbeCount) { // If we have no probe suppression time set, or it is in the past, set it now if (m->SuppressProbes == 0 || m->SuppressProbes - m->timenow < 0) { // To allow us to aggregate probes when a group of services are registered together, // the first probe is delayed by a random delay in the range 1/8 to 1/4 second. // This means the common-case behaviour is: // randomized wait; probe // 1/4 second wait; probe // 1/4 second wait; probe // 1/4 second wait; announce (i.e. service is normally announced 7/8 to 1 second after being registered) m->SuppressProbes = NonZeroTime(m->timenow + DefaultProbeIntervalForTypeUnique/2 + mDNSRandom(DefaultProbeIntervalForTypeUnique/2)); // If we already have a *probe* scheduled to go out sooner, then use that time to get better aggregation if (m->SuppressProbes - m->NextScheduledProbe >= 0) m->SuppressProbes = NonZeroTime(m->NextScheduledProbe); if (m->SuppressProbes - m->timenow < 0) // Make sure we don't set m->SuppressProbes excessively in the past m->SuppressProbes = m->timenow; // If we already have a *query* scheduled to go out sooner, then use that time to get better aggregation if (m->SuppressProbes - m->NextScheduledQuery >= 0) m->SuppressProbes = NonZeroTime(m->NextScheduledQuery); if (m->SuppressProbes - m->timenow < 0) // Make sure we don't set m->SuppressProbes excessively in the past m->SuppressProbes = m->timenow; // except... don't expect to be able to send before the m->SuppressSending timer fires if (m->SuppressSending && m->SuppressProbes - m->SuppressSending < 0) m->SuppressProbes = NonZeroTime(m->SuppressSending); if (m->SuppressProbes - m->timenow > mDNSPlatformOneSecond * 8) { LogMsg("InitializeLastAPTime ERROR m->SuppressProbes %d m->NextScheduledProbe %d m->NextScheduledQuery %d m->SuppressSending %d %d", m->SuppressProbes - m->timenow, m->NextScheduledProbe - m->timenow, m->NextScheduledQuery - m->timenow, m->SuppressSending, m->SuppressSending - m->timenow); m->SuppressProbes = NonZeroTime(m->timenow + DefaultProbeIntervalForTypeUnique/2 + mDNSRandom(DefaultProbeIntervalForTypeUnique/2)); } } rr->LastAPTime = m->SuppressProbes - rr->ThisAPInterval; } // Skip kDNSRecordTypeKnownUnique and kDNSRecordTypeShared records here and set their LastAPTime in the "else" block below so // that they get announced immediately, otherwise, their announcement would be delayed until the based on the SuppressProbes value. else if ((rr->resrec.RecordType != kDNSRecordTypeKnownUnique) && (rr->resrec.RecordType != kDNSRecordTypeShared) && m->SuppressProbes && (m->SuppressProbes - m->timenow >= 0)) rr->LastAPTime = m->SuppressProbes - rr->ThisAPInterval + DefaultProbeIntervalForTypeUnique * DefaultProbeCountForTypeUnique + rr->ThisAPInterval / 2; else rr->LastAPTime = m->timenow - rr->ThisAPInterval; // For reverse-mapping Sleep Proxy PTR records we don't want to start probing instantly -- we // wait one second to give the client a chance to go to sleep, and then start our ARP/NDP probing. // After three probes one second apart with no answer, we conclude the client is now sleeping // and we can begin broadcasting our announcements to take over ownership of that IP address. // If we don't wait for the client to go to sleep, then when the client sees our ARP Announcements there's a risk // (depending on the OS and networking stack it's using) that it might interpret it as a conflict and change its IP address. if (rr->AddressProxy.type) rr->LastAPTime = m->timenow; // Set LastMCTime to now, to inhibit multicast responses // (no need to send additional multicast responses when we're announcing anyway) rr->LastMCTime = m->timenow; rr->LastMCInterface = mDNSInterfaceMark; SetNextAnnounceProbeTime(m, rr); } mDNSlocal const domainname *SetUnicastTargetToHostName(mDNS *const m, AuthRecord *rr) { const domainname *target; if (rr->AutoTarget) { // For autotunnel services pointing at our IPv6 ULA we don't need or want a NAT mapping, but for all other // advertised services referencing our uDNS hostname, we want NAT mappings automatically created as appropriate, // with the port number in our advertised SRV record automatically tracking the external mapped port. DomainAuthInfo *AuthInfo = GetAuthInfoForName_internal(m, rr->resrec.name); if (!AuthInfo || !AuthInfo->AutoTunnel) rr->AutoTarget = Target_AutoHostAndNATMAP; } target = GetServiceTarget(m, rr); if (!target || target->c[0] == 0) { // defer registration until we've got a target LogInfo("SetUnicastTargetToHostName No target for %s", ARDisplayString(m, rr)); rr->state = regState_NoTarget; return mDNSNULL; } else { LogInfo("SetUnicastTargetToHostName target %##s for resource record %s", target->c, ARDisplayString(m,rr)); return target; } } // Right now this only applies to mDNS (.local) services where the target host is always m->MulticastHostname // Eventually we should unify this with GetServiceTarget() in uDNS.c mDNSlocal void SetTargetToHostName(mDNS *const m, AuthRecord *const rr) { domainname *const target = GetRRDomainNameTarget(&rr->resrec); const domainname *newname = &m->MulticastHostname; if (!target) LogInfo("SetTargetToHostName: Don't know how to set the target of rrtype %s", DNSTypeName(rr->resrec.rrtype)); if (!(rr->ForceMCast || rr->ARType == AuthRecordLocalOnly || rr->ARType == AuthRecordP2P || IsLocalDomain(&rr->namestorage))) { const domainname *const n = SetUnicastTargetToHostName(m, rr); if (n) newname = n; else { if (target) target->c[0] = 0; SetNewRData(&rr->resrec, mDNSNULL, 0); return; } } if (target && SameDomainName(target, newname)) debugf("SetTargetToHostName: Target of %##s is already %##s", rr->resrec.name->c, target->c); if (target && !SameDomainName(target, newname)) { AssignDomainName(target, newname); SetNewRData(&rr->resrec, mDNSNULL, 0); // Update rdlength, rdestimate, rdatahash // If we're in the middle of probing this record, we need to start again, // because changing its rdata may change the outcome of the tie-breaker. // (If the record type is kDNSRecordTypeUnique (unconfirmed unique) then DefaultProbeCountForRecordType is non-zero.) rr->ProbeCount = DefaultProbeCountForRecordType(rr->resrec.RecordType); // If we've announced this record, we really should send a goodbye packet for the old rdata before // changing to the new rdata. However, in practice, we only do SetTargetToHostName for unique records, // so when we announce them we'll set the kDNSClass_UniqueRRSet and clear any stale data that way. if (rr->RequireGoodbye && rr->resrec.RecordType == kDNSRecordTypeShared) debugf("Have announced shared record %##s (%s) at least once: should have sent a goodbye packet before updating", rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); rr->AnnounceCount = InitialAnnounceCount; rr->RequireGoodbye = mDNSfalse; rr->ProbeRestartCount = 0; InitializeLastAPTime(m, rr); } } mDNSlocal void AcknowledgeRecord(mDNS *const m, AuthRecord *const rr) { if (rr->RecordCallback) { // CAUTION: MUST NOT do anything more with rr after calling rr->Callback(), because the client's callback function // is allowed to do anything, including starting/stopping queries, registering/deregistering records, etc. rr->Acknowledged = mDNStrue; mDNS_DropLockBeforeCallback(); // Allow client to legally make mDNS API calls from the callback rr->RecordCallback(m, rr, mStatus_NoError); mDNS_ReclaimLockAfterCallback(); // Decrement mDNS_reentrancy to block mDNS API calls again } } mDNSexport void ActivateUnicastRegistration(mDNS *const m, AuthRecord *const rr) { // Make sure that we don't activate the SRV record and associated service records, if it is in // NoTarget state. First time when a service is being instantiated, SRV record may be in NoTarget state. // We should not activate any of the other reords (PTR, TXT) that are part of the service. When // the target becomes available, the records will be reregistered. if (rr->resrec.rrtype != kDNSType_SRV) { AuthRecord *srvRR = mDNSNULL; if (rr->resrec.rrtype == kDNSType_PTR) srvRR = rr->Additional1; else if (rr->resrec.rrtype == kDNSType_TXT) srvRR = rr->DependentOn; if (srvRR) { if (srvRR->resrec.rrtype != kDNSType_SRV) { LogMsg("ActivateUnicastRegistration: ERROR!! Resource record %s wrong, expecting SRV type", ARDisplayString(m, srvRR)); } else { LogInfo("ActivateUnicastRegistration: Found Service Record %s in state %d for %##s (%s)", ARDisplayString(m, srvRR), srvRR->state, rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); rr->state = srvRR->state; } } } if (rr->state == regState_NoTarget) { LogInfo("ActivateUnicastRegistration record %s in regState_NoTarget, not activating", ARDisplayString(m, rr)); return; } // When we wake up from sleep, we call ActivateUnicastRegistration. It is possible that just before we went to sleep, // the service/record was being deregistered. In that case, we should not try to register again. For the cases where // the records are deregistered due to e.g., no target for the SRV record, we would have returned from above if it // was already in NoTarget state. If it was in the process of deregistration but did not complete fully before we went // to sleep, then it is okay to start in Pending state as we will go back to NoTarget state if we don't have a target. if (rr->resrec.RecordType == kDNSRecordTypeDeregistering) { LogInfo("ActivateUnicastRegistration: Resource record %s, current state %d, moving to DeregPending", ARDisplayString(m, rr), rr->state); rr->state = regState_DeregPending; } else { LogInfo("ActivateUnicastRegistration: Resource record %s, current state %d, moving to Pending", ARDisplayString(m, rr), rr->state); rr->state = regState_Pending; } rr->ProbeCount = 0; rr->ProbeRestartCount = 0; rr->AnnounceCount = 0; rr->ThisAPInterval = INIT_RECORD_REG_INTERVAL; rr->LastAPTime = m->timenow - rr->ThisAPInterval; rr->expire = 0; // Forget about all the leases, start fresh rr->uselease = mDNStrue; rr->updateid = zeroID; rr->SRVChanged = mDNSfalse; rr->updateError = mStatus_NoError; // RestartRecordGetZoneData calls this function whenever a new interface gets registered with core. // The records might already be registered with the server and hence could have NAT state. if (rr->NATinfo.clientContext) { mDNS_StopNATOperation_internal(m, &rr->NATinfo); rr->NATinfo.clientContext = mDNSNULL; } if (rr->nta) { CancelGetZoneData(m, rr->nta); rr->nta = mDNSNULL; } if (rr->tcp) { DisposeTCPConn(rr->tcp); rr->tcp = mDNSNULL; } if (m->NextuDNSEvent - (rr->LastAPTime + rr->ThisAPInterval) >= 0) m->NextuDNSEvent = (rr->LastAPTime + rr->ThisAPInterval); } // Two records qualify to be local duplicates if: // (a) the RecordTypes are the same, or // (b) one is Unique and the other Verified // (c) either is in the process of deregistering #define RecordLDT(A,B) ((A)->resrec.RecordType == (B)->resrec.RecordType || \ ((A)->resrec.RecordType | (B)->resrec.RecordType) == (kDNSRecordTypeUnique | kDNSRecordTypeVerified) || \ ((A)->resrec.RecordType == kDNSRecordTypeDeregistering || (B)->resrec.RecordType == kDNSRecordTypeDeregistering)) #define RecordIsLocalDuplicate(A,B) \ ((A)->resrec.InterfaceID == (B)->resrec.InterfaceID && RecordLDT((A),(B)) && IdenticalResourceRecord(& (A)->resrec, & (B)->resrec)) mDNSlocal AuthRecord *CheckAuthIdenticalRecord(AuthHash *r, AuthRecord *rr) { const AuthGroup *a; AuthRecord *rp; a = AuthGroupForRecord(r, &rr->resrec); if (!a) return mDNSNULL; rp = a->members; while (rp) { if (!RecordIsLocalDuplicate(rp, rr)) rp = rp->next; else { if (rp->resrec.RecordType == kDNSRecordTypeDeregistering) { rp->AnnounceCount = 0; rp = rp->next; } else return rp; } } return (mDNSNULL); } mDNSlocal mDNSBool CheckAuthRecordConflict(AuthHash *r, AuthRecord *rr) { const AuthGroup *a; const AuthRecord *rp; a = AuthGroupForRecord(r, &rr->resrec); if (!a) return mDNSfalse; rp = a->members; while (rp) { const AuthRecord *s1 = rr->RRSet ? rr->RRSet : rr; const AuthRecord *s2 = rp->RRSet ? rp->RRSet : rp; if (s1 != s2 && SameResourceRecordSignature(rp, rr) && !IdenticalSameNameRecord(&rp->resrec, &rr->resrec)) return mDNStrue; else rp = rp->next; } return (mDNSfalse); } // checks to see if "rr" is already present mDNSlocal AuthRecord *CheckAuthSameRecord(AuthHash *r, AuthRecord *rr) { const AuthGroup *a; AuthRecord *rp; a = AuthGroupForRecord(r, &rr->resrec); if (!a) return mDNSNULL; rp = a->members; while (rp) { if (rp != rr) rp = rp->next; else { return rp; } } return (mDNSNULL); } mDNSlocal void DecrementAutoTargetServices(mDNS *const m, AuthRecord *const rr) { if (RRLocalOnly(rr)) { // A sanity check, this should be prevented in calling code. LogInfo("DecrementAutoTargetServices: called for RRLocalOnly() record: %s", ARDisplayString(m, rr)); return; } if (!AuthRecord_uDNS(rr) && rr->resrec.rrtype == kDNSType_SRV && rr->AutoTarget == Target_AutoHost) { // If about to get rid of the last advertised service if (m->AutoTargetServices == 1) DeadvertiseAllInterfaceRecords(m); m->AutoTargetServices--; LogInfo("DecrementAutoTargetServices: AutoTargetServices %d Record %s", m->AutoTargetServices, ARDisplayString(m, rr)); } #if BONJOUR_ON_DEMAND if (!AuthRecord_uDNS(rr)) { if (m->NumAllInterfaceRecords + m->NumAllInterfaceQuestions == 1) m->NextBonjourDisableTime = NonZeroTime(m->timenow + (BONJOUR_DISABLE_DELAY * mDNSPlatformOneSecond)); m->NumAllInterfaceRecords--; LogInfo("DecrementAutoTargetServices: NumAllInterfaceRecords %d NumAllInterfaceQuestions %d %s", m->NumAllInterfaceRecords, m->NumAllInterfaceQuestions, ARDisplayString(m, rr)); } #endif // BONJOUR_ON_DEMAND } mDNSlocal void IncrementAutoTargetServices(mDNS *const m, AuthRecord *const rr) { mDNSBool enablingBonjour = 0; if (RRLocalOnly(rr)) { // A sanity check, this should be prevented in calling code. LogInfo("IncrementAutoTargetServices: called for RRLocalOnly() record: %s", ARDisplayString(m, rr)); return; } #if BONJOUR_ON_DEMAND if (!AuthRecord_uDNS(rr)) { m->NumAllInterfaceRecords++; LogInfo("IncrementAutoTargetServices: NumAllInterfaceRecords %d NumAllInterfaceQuestions %d %s", m->NumAllInterfaceRecords, m->NumAllInterfaceQuestions, ARDisplayString(m, rr)); if (m->NumAllInterfaceRecords + m->NumAllInterfaceQuestions == 1) { m->NextBonjourDisableTime = 0; if (m->BonjourEnabled == 0) { // Enable Bonjour immediately by scheduling network changed processing where // we will join the multicast group on each active interface. m->BonjourEnabled = 1; enablingBonjour = 1; m->NetworkChanged = m->timenow; } } } #endif // BONJOUR_ON_DEMAND if (!AuthRecord_uDNS(rr) && rr->resrec.rrtype == kDNSType_SRV && rr->AutoTarget == Target_AutoHost) { m->AutoTargetServices++; LogInfo("IncrementAutoTargetServices: AutoTargetServices %d Record %s", m->AutoTargetServices, ARDisplayString(m, rr)); // If this is the first advertised service and we did not just enable Bonjour above, then // advertise all the interface records. If we did enable Bonjour above, the interface records will // be advertised during the network changed processing scheduled above, so no need // to do it here. if ((m->AutoTargetServices == 1) && (enablingBonjour == 0)) AdvertiseAllInterfaceRecords(m); } } mDNSlocal void getKeepaliveRaddr(mDNS *const m, AuthRecord *rr, mDNSAddr *raddr) { mDNSAddr laddr = zeroAddr; mDNSEthAddr eth = zeroEthAddr; mDNSIPPort lport = zeroIPPort; mDNSIPPort rport = zeroIPPort; mDNSu32 timeout = 0; mDNSu32 seq = 0; mDNSu32 ack = 0; mDNSu16 win = 0; if (mDNS_KeepaliveRecord(&rr->resrec)) { mDNS_ExtractKeepaliveInfo(rr, &timeout, &laddr, raddr, ð, &seq, &ack, &lport, &rport, &win); if (!timeout || mDNSAddressIsZero(&laddr) || mDNSAddressIsZero(raddr) || mDNSIPPortIsZero(lport) || mDNSIPPortIsZero(rport)) { LogMsg("getKeepaliveRaddr: not a valid record %s for keepalive %#a:%d %#a:%d", ARDisplayString(m, rr), &laddr, lport.NotAnInteger, raddr, rport.NotAnInteger); return; } } } // Exported so uDNS.c can call this mDNSexport mStatus mDNS_Register_internal(mDNS *const m, AuthRecord *const rr) { domainname *target = GetRRDomainNameTarget(&rr->resrec); AuthRecord *r; AuthRecord **p = &m->ResourceRecords; AuthRecord **d = &m->DuplicateRecords; if ((mDNSs32)rr->resrec.rroriginalttl <= 0) { LogMsg("mDNS_Register_internal: TTL %X should be 1 - 0x7FFFFFFF %s", rr->resrec.rroriginalttl, ARDisplayString(m, rr)); return(mStatus_BadParamErr); } if (!rr->resrec.RecordType) { LogMsg("mDNS_Register_internal: RecordType must be non-zero %s", ARDisplayString(m, rr)); return(mStatus_BadParamErr); } if (m->ShutdownTime) { LogMsg("mDNS_Register_internal: Shutting down, can't register %s", ARDisplayString(m, rr)); return(mStatus_ServiceNotRunning); } if (m->DivertMulticastAdvertisements && !AuthRecord_uDNS(rr)) { mDNSInterfaceID previousID = rr->resrec.InterfaceID; if (rr->resrec.InterfaceID == mDNSInterface_Any || rr->resrec.InterfaceID == mDNSInterface_P2P) { rr->resrec.InterfaceID = mDNSInterface_LocalOnly; rr->ARType = AuthRecordLocalOnly; } if (rr->resrec.InterfaceID != mDNSInterface_LocalOnly) { NetworkInterfaceInfo *intf = FirstInterfaceForID(m, rr->resrec.InterfaceID); if (intf && !intf->Advertise) { rr->resrec.InterfaceID = mDNSInterface_LocalOnly; rr->ARType = AuthRecordLocalOnly; } } if (rr->resrec.InterfaceID != previousID) LogInfo("mDNS_Register_internal: Diverting record to local-only %s", ARDisplayString(m, rr)); } if (RRLocalOnly(rr)) { if (CheckAuthSameRecord(&m->rrauth, rr)) { LogMsg("mDNS_Register_internal: ERROR!! Tried to register LocalOnly AuthRecord %p %##s (%s) that's already in the list", rr, rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); return(mStatus_AlreadyRegistered); } } else { while (*p && *p != rr) p=&(*p)->next; if (*p) { LogMsg("mDNS_Register_internal: ERROR!! Tried to register AuthRecord %p %##s (%s) that's already in the list", rr, rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); return(mStatus_AlreadyRegistered); } } while (*d && *d != rr) d=&(*d)->next; if (*d) { LogMsg("mDNS_Register_internal: ERROR!! Tried to register AuthRecord %p %##s (%s) that's already in the Duplicate list", rr, rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); return(mStatus_AlreadyRegistered); } if (rr->DependentOn) { if (rr->resrec.RecordType == kDNSRecordTypeUnique) rr->resrec.RecordType = kDNSRecordTypeVerified; else if (rr->resrec.RecordType != kDNSRecordTypeKnownUnique) { LogMsg("mDNS_Register_internal: ERROR! %##s (%s): rr->DependentOn && RecordType != kDNSRecordTypeUnique or kDNSRecordTypeKnownUnique", rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); return(mStatus_Invalid); } if (!(rr->DependentOn->resrec.RecordType & (kDNSRecordTypeUnique | kDNSRecordTypeVerified | kDNSRecordTypeKnownUnique))) { LogMsg("mDNS_Register_internal: ERROR! %##s (%s): rr->DependentOn->RecordType bad type %X", rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype), rr->DependentOn->resrec.RecordType); return(mStatus_Invalid); } } rr->next = mDNSNULL; // Field Group 1: The actual information pertaining to this resource record // Set up by client prior to call // Field Group 2: Persistent metadata for Authoritative Records // rr->Additional1 = set to mDNSNULL in mDNS_SetupResourceRecord; may be overridden by client // rr->Additional2 = set to mDNSNULL in mDNS_SetupResourceRecord; may be overridden by client // rr->DependentOn = set to mDNSNULL in mDNS_SetupResourceRecord; may be overridden by client // rr->RRSet = set to mDNSNULL in mDNS_SetupResourceRecord; may be overridden by client // rr->Callback = already set in mDNS_SetupResourceRecord // rr->Context = already set in mDNS_SetupResourceRecord // rr->RecordType = already set in mDNS_SetupResourceRecord // rr->HostTarget = set to mDNSfalse in mDNS_SetupResourceRecord; may be overridden by client // rr->AllowRemoteQuery = set to mDNSfalse in mDNS_SetupResourceRecord; may be overridden by client // Make sure target is not uninitialized data, or we may crash writing debugging log messages if (rr->AutoTarget && target) target->c[0] = 0; // Field Group 3: Transient state for Authoritative Records rr->Acknowledged = mDNSfalse; rr->ProbeCount = DefaultProbeCountForRecordType(rr->resrec.RecordType); rr->ProbeRestartCount = 0; rr->AnnounceCount = InitialAnnounceCount; rr->RequireGoodbye = mDNSfalse; rr->AnsweredLocalQ = mDNSfalse; rr->IncludeInProbe = mDNSfalse; rr->ImmedUnicast = mDNSfalse; rr->SendNSECNow = mDNSNULL; rr->ImmedAnswer = mDNSNULL; rr->ImmedAdditional = mDNSNULL; rr->SendRNow = mDNSNULL; rr->v4Requester = zerov4Addr; rr->v6Requester = zerov6Addr; rr->NextResponse = mDNSNULL; rr->NR_AnswerTo = mDNSNULL; rr->NR_AdditionalTo = mDNSNULL; if (!rr->AutoTarget) InitializeLastAPTime(m, rr); // rr->LastAPTime = Set for us in InitializeLastAPTime() // rr->LastMCTime = Set for us in InitializeLastAPTime() // rr->LastMCInterface = Set for us in InitializeLastAPTime() rr->NewRData = mDNSNULL; rr->newrdlength = 0; rr->UpdateCallback = mDNSNULL; rr->UpdateCredits = kMaxUpdateCredits; rr->NextUpdateCredit = 0; rr->UpdateBlocked = 0; // For records we're holding as proxy (except reverse-mapping PTR records) two announcements is sufficient if (rr->WakeUp.HMAC.l[0] && !rr->AddressProxy.type) rr->AnnounceCount = 2; // Field Group 4: Transient uDNS state for Authoritative Records rr->state = regState_Zero; rr->uselease = 0; rr->expire = 0; rr->Private = 0; rr->updateid = zeroID; rr->updateIntID = zeroOpaque64; rr->zone = rr->resrec.name; rr->nta = mDNSNULL; rr->tcp = mDNSNULL; rr->OrigRData = 0; rr->OrigRDLen = 0; rr->InFlightRData = 0; rr->InFlightRDLen = 0; rr->QueuedRData = 0; rr->QueuedRDLen = 0; //mDNSPlatformMemZero(&rr->NATinfo, sizeof(rr->NATinfo)); // We should be recording the actual internal port for this service record here. Once we initiate our NAT mapping // request we'll subsequently overwrite srv.port with the allocated external NAT port -- potentially multiple // times with different values if the external NAT port changes during the lifetime of the service registration. //if (rr->resrec.rrtype == kDNSType_SRV) rr->NATinfo.IntPort = rr->resrec.rdata->u.srv.port; // rr->resrec.interface = already set in mDNS_SetupResourceRecord // rr->resrec.name->c = MUST be set by client // rr->resrec.rrtype = already set in mDNS_SetupResourceRecord // rr->resrec.rrclass = already set in mDNS_SetupResourceRecord // rr->resrec.rroriginalttl = already set in mDNS_SetupResourceRecord // rr->resrec.rdata = MUST be set by client, unless record type is CNAME or PTR and rr->HostTarget is set // BIND named (name daemon) doesn't allow TXT records with zero-length rdata. This is strictly speaking correct, // since RFC 1035 specifies a TXT record as "One or more s", not "Zero or more s". // Since some legacy apps try to create zero-length TXT records, we'll silently correct it here. if (rr->resrec.rrtype == kDNSType_TXT && rr->resrec.rdlength == 0) { rr->resrec.rdlength = 1; rr->resrec.rdata->u.txt.c[0] = 0; } if (rr->AutoTarget) { SetTargetToHostName(m, rr); // Also sets rdlength and rdestimate for us, and calls InitializeLastAPTime(); #ifndef UNICAST_DISABLED // If we have no target record yet, SetTargetToHostName will set rr->state == regState_NoTarget // In this case we leave the record half-formed in the list, and later we'll remove it from the list and re-add it properly. if (rr->state == regState_NoTarget) { // Initialize the target so that we don't crash while logging etc. domainname *tar = GetRRDomainNameTarget(&rr->resrec); if (tar) tar->c[0] = 0; LogInfo("mDNS_Register_internal: record %s in NoTarget state", ARDisplayString(m, rr)); } #endif } else { rr->resrec.rdlength = GetRDLength(&rr->resrec, mDNSfalse); rr->resrec.rdestimate = GetRDLength(&rr->resrec, mDNStrue); } if (!ValidateDomainName(rr->resrec.name)) { LogMsg("Attempt to register record with invalid name: %s", ARDisplayString(m, rr)); return(mStatus_Invalid); } // Don't do this until *after* we've set rr->resrec.rdlength if (!ValidateRData(rr->resrec.rrtype, rr->resrec.rdlength, rr->resrec.rdata)) { LogMsg("Attempt to register record with invalid rdata: %s", ARDisplayString(m, rr)); return(mStatus_Invalid); } rr->resrec.namehash = DomainNameHashValue(rr->resrec.name); rr->resrec.rdatahash = target ? DomainNameHashValue(target) : RDataHashValue(&rr->resrec); if (RRLocalOnly(rr)) { // If this is supposed to be unique, make sure we don't have any name conflicts. // If we found a conflict, we may still want to insert the record in the list but mark it appropriately // (kDNSRecordTypeDeregistering) so that we deliver RMV events to the application. But this causes more // complications and not clear whether there are any benefits. See rdar:9304275 for details. // Hence, just bail out. // This comment is doesn’t make any sense. -- SC if (rr->resrec.RecordType & kDNSRecordTypeUniqueMask) { if (CheckAuthRecordConflict(&m->rrauth, rr)) { LogInfo("mDNS_Register_internal: Name conflict %s (%p), InterfaceID %p", ARDisplayString(m, rr), rr, rr->resrec.InterfaceID); return mStatus_NameConflict; } } } // For uDNS records, we don't support duplicate checks at this time. #ifndef UNICAST_DISABLED if (AuthRecord_uDNS(rr)) { if (!m->NewLocalRecords) m->NewLocalRecords = rr; // When we called SetTargetToHostName, it may have caused mDNS_Register_internal to be re-entered, appending new // records to the list, so we now need to update p to advance to the new end to the list before appending our new record. // Note that for AutoTunnel this should never happen, but this check makes the code future-proof. while (*p) p=&(*p)->next; *p = rr; if (rr->resrec.RecordType == kDNSRecordTypeUnique) rr->resrec.RecordType = kDNSRecordTypeVerified; rr->ProbeCount = 0; rr->ProbeRestartCount = 0; rr->AnnounceCount = 0; if (rr->state != regState_NoTarget) ActivateUnicastRegistration(m, rr); return(mStatus_NoError); // <--- Note: For unicast records, code currently bails out at this point } #endif // Now that we've finished building our new record, make sure it's not identical to one we already have if (RRLocalOnly(rr)) { rr->ProbeCount = 0; rr->ProbeRestartCount = 0; rr->AnnounceCount = 0; r = CheckAuthIdenticalRecord(&m->rrauth, rr); } else { for (r = m->ResourceRecords; r; r=r->next) if (RecordIsLocalDuplicate(r, rr)) { if (r->resrec.RecordType == kDNSRecordTypeDeregistering) r->AnnounceCount = 0; else break; } } if (r) { LogInfo("mDNS_Register_internal: Adding to duplicate list %s", ARDisplayString(m,rr)); *d = rr; // If the previous copy of this record is already verified unique, // then indicate that we should move this record promptly to kDNSRecordTypeUnique state. // Setting ProbeCount to zero will cause SendQueries() to advance this record to // kDNSRecordTypeVerified state and call the client callback at the next appropriate time. if (rr->resrec.RecordType == kDNSRecordTypeUnique && r->resrec.RecordType == kDNSRecordTypeVerified) rr->ProbeCount = 0; } else { LogInfo("mDNS_Register_internal: Adding to active record list %s", ARDisplayString(m,rr)); if (RRLocalOnly(rr)) { AuthGroup *ag; ag = InsertAuthRecord(m, &m->rrauth, rr); if (ag && !ag->NewLocalOnlyRecords) { m->NewLocalOnlyRecords = mDNStrue; ag->NewLocalOnlyRecords = rr; } // No probing for LocalOnly records; acknowledge them right away if (rr->resrec.RecordType == kDNSRecordTypeUnique) rr->resrec.RecordType = kDNSRecordTypeVerified; AcknowledgeRecord(m, rr); return(mStatus_NoError); } else { if (!m->NewLocalRecords) m->NewLocalRecords = rr; *p = rr; } } if (!AuthRecord_uDNS(rr)) // This check is superfluous, given that for unicast records we (currently) bail out above { // We have inserted the record in the list. See if we have to advertise the A/AAAA, HINFO, PTR records. IncrementAutoTargetServices(m, rr); // For records that are not going to probe, acknowledge them right away if (rr->resrec.RecordType != kDNSRecordTypeUnique && rr->resrec.RecordType != kDNSRecordTypeDeregistering) AcknowledgeRecord(m, rr); // Adding a record may affect whether or not we should sleep mDNS_UpdateAllowSleep(m); } // If this is a non-sleep proxy keepalive record, fetch the MAC address of the remote host. // This is used by the in-NIC proxy to send the keepalive packets. if (!rr->WakeUp.HMAC.l[0] && mDNS_KeepaliveRecord(&rr->resrec)) { mDNSAddr raddr; // Set the record type to known unique to prevent probing keep alive records. // Also make sure we do not announce the keepalive records. rr->resrec.RecordType = kDNSRecordTypeKnownUnique; rr->AnnounceCount = 0; getKeepaliveRaddr(m, rr, &raddr); // This is an asynchronous call. Once the remote MAC address is available, helper will schedule an // asynchronous task to update the resource record mDNSPlatformGetRemoteMacAddr(&raddr); } return(mStatus_NoError); } mDNSlocal void RecordProbeFailure(mDNS *const m, const AuthRecord *const rr) { m->ProbeFailTime = m->timenow; m->NumFailedProbes++; // If we've had fifteen or more probe failures, rate-limit to one every five seconds. // If a bunch of hosts have all been configured with the same name, then they'll all // conflict and run through the same series of names: name-2, name-3, name-4, etc., // up to name-10. After that they'll start adding random increments in the range 1-100, // so they're more likely to branch out in the available namespace and settle on a set of // unique names quickly. If after five more tries the host is still conflicting, then we // may have a serious problem, so we start rate-limiting so we don't melt down the network. if (m->NumFailedProbes >= 15) { m->SuppressProbes = NonZeroTime(m->timenow + mDNSPlatformOneSecond * 5); LogMsg("Excessive name conflicts (%lu) for %##s (%s); rate limiting in effect", m->NumFailedProbes, rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); } } mDNSlocal void CompleteRDataUpdate(mDNS *const m, AuthRecord *const rr) { RData *OldRData = rr->resrec.rdata; mDNSu16 OldRDLen = rr->resrec.rdlength; SetNewRData(&rr->resrec, rr->NewRData, rr->newrdlength); // Update our rdata rr->NewRData = mDNSNULL; // Clear the NewRData pointer ... if (rr->UpdateCallback) rr->UpdateCallback(m, rr, OldRData, OldRDLen); // ... and let the client know } // Note: mDNS_Deregister_internal can call a user callback, which may change the record list and/or question list. // Any code walking either list must use the CurrentQuestion and/or CurrentRecord mechanism to protect against this. // Exported so uDNS.c can call this mDNSexport mStatus mDNS_Deregister_internal(mDNS *const m, AuthRecord *const rr, mDNS_Dereg_type drt) { AuthRecord *r2; mDNSu8 RecordType = rr->resrec.RecordType; AuthRecord **p = &m->ResourceRecords; // Find this record in our list of active records mDNSBool dupList = mDNSfalse; if (RRLocalOnly(rr)) { AuthGroup *a; AuthRecord **rp; a = AuthGroupForRecord(&m->rrauth, &rr->resrec); if (!a) return mDNSfalse; rp = &a->members; while (*rp && *rp != rr) rp=&(*rp)->next; p = rp; } else { while (*p && *p != rr) p=&(*p)->next; } if (*p) { // We found our record on the main list. See if there are any duplicates that need special handling. if (drt == mDNS_Dereg_conflict) // If this was a conflict, see that all duplicates get the same treatment { // Scan for duplicates of rr, and mark them for deregistration at the end of this routine, after we've finished // deregistering rr. We need to do this scan *before* we give the client the chance to free and reuse the rr memory. for (r2 = m->DuplicateRecords; r2; r2=r2->next) if (RecordIsLocalDuplicate(r2, rr)) r2->ProbeCount = 0xFF; } else { // Before we delete the record (and potentially send a goodbye packet) // first see if we have a record on the duplicate list ready to take over from it. AuthRecord **d = &m->DuplicateRecords; while (*d && !RecordIsLocalDuplicate(*d, rr)) d=&(*d)->next; if (*d) { AuthRecord *dup = *d; debugf("mDNS_Register_internal: Duplicate record %p taking over from %p %##s (%s)", dup, rr, rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); *d = dup->next; // Cut replacement record from DuplicateRecords list if (RRLocalOnly(rr)) { dup->next = mDNSNULL; if (!InsertAuthRecord(m, &m->rrauth, dup)) LogMsg("mDNS_Deregister_internal: ERROR!! cannot insert %s", ARDisplayString(m, dup)); } else { dup->next = rr->next; // And then... rr->next = dup; // ... splice it in right after the record we're about to delete } dup->resrec.RecordType = rr->resrec.RecordType; dup->ProbeCount = rr->ProbeCount; dup->ProbeRestartCount = rr->ProbeRestartCount; dup->AnnounceCount = rr->AnnounceCount; dup->RequireGoodbye = rr->RequireGoodbye; dup->AnsweredLocalQ = rr->AnsweredLocalQ; dup->ImmedAnswer = rr->ImmedAnswer; dup->ImmedUnicast = rr->ImmedUnicast; dup->ImmedAdditional = rr->ImmedAdditional; dup->v4Requester = rr->v4Requester; dup->v6Requester = rr->v6Requester; dup->ThisAPInterval = rr->ThisAPInterval; dup->LastAPTime = rr->LastAPTime; dup->LastMCTime = rr->LastMCTime; dup->LastMCInterface = rr->LastMCInterface; dup->Private = rr->Private; dup->state = rr->state; rr->RequireGoodbye = mDNSfalse; rr->AnsweredLocalQ = mDNSfalse; } } } else { // We didn't find our record on the main list; try the DuplicateRecords list instead. p = &m->DuplicateRecords; while (*p && *p != rr) p=&(*p)->next; // If we found our record on the duplicate list, then make sure we don't send a goodbye for it if (*p) { // Duplicate records are not used for sending wakeups or goodbyes. Hence, deregister them // immediately. When there is a conflict, we deregister all the conflicting duplicate records // also that have been marked above in this function. In that case, we come here and if we don't // deregister (unilink from the DuplicateRecords list), we will be recursing infinitely. Hence, // clear the HMAC which will cause it to deregister. See for // details. rr->WakeUp.HMAC = zeroEthAddr; rr->RequireGoodbye = mDNSfalse; rr->resrec.RecordType = kDNSRecordTypeDeregistering; dupList = mDNStrue; } if (*p) debugf("mDNS_Deregister_internal: Deleting DuplicateRecord %p %##s (%s)", rr, rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); } if (!*p) { // No need to log an error message if we already know this is a potentially repeated deregistration if (drt != mDNS_Dereg_repeat) LogMsg("mDNS_Deregister_internal: Record %p not found in list %s", rr, ARDisplayString(m,rr)); return(mStatus_BadReferenceErr); } // If this is a shared record and we've announced it at least once, // we need to retract that announcement before we delete the record // If this is a record (including mDNSInterface_LocalOnly records) for which we've given local-only answers then // it's tempting to just do "AnswerAllLocalQuestionsWithLocalAuthRecord(m, rr, mDNSfalse)" here, but that would not not be safe. // The AnswerAllLocalQuestionsWithLocalAuthRecord routine walks the question list invoking client callbacks, using the "m->CurrentQuestion" // mechanism to cope with the client callback modifying the question list while that's happening. // However, mDNS_Deregister could have been called from a client callback (e.g. from the domain enumeration callback FoundDomain) // which means that the "m->CurrentQuestion" mechanism is already in use to protect that list, so we can't use it twice. // More generally, if we invoke callbacks from within a client callback, then those callbacks could deregister other // records, thereby invoking yet more callbacks, without limit. // The solution is to defer delivering the "Remove" events until mDNS_Execute time, just like we do for sending // actual goodbye packets. #ifndef UNICAST_DISABLED if (AuthRecord_uDNS(rr)) { if (rr->RequireGoodbye) { if (rr->tcp) { DisposeTCPConn(rr->tcp); rr->tcp = mDNSNULL; } rr->resrec.RecordType = kDNSRecordTypeDeregistering; m->LocalRemoveEvents = mDNStrue; uDNS_DeregisterRecord(m, rr); // At this point unconditionally we bail out // Either uDNS_DeregisterRecord will have completed synchronously, and called CompleteDeregistration, // which calls us back here with RequireGoodbye set to false, or it will have initiated the deregistration // process and will complete asynchronously. Either way we don't need to do anything more here. return(mStatus_NoError); } // Sometimes the records don't complete proper deregistration i.e., don't wait for a response // from the server. In that case, if the records have been part of a group update, clear the // state here. Some recors e.g., AutoTunnel gets reused without ever being completely initialized rr->updateid = zeroID; // We defer cleaning up NAT state only after sending goodbyes. This is important because // RecordRegistrationGotZoneData guards against creating NAT state if clientContext is non-NULL. // This happens today when we turn on/off interface where we get multiple network transitions // and RestartRecordGetZoneData triggers re-registration of the resource records even though // they may be in Registered state which causes NAT information to be setup multiple times. Defering // the cleanup here keeps clientContext non-NULL and hence prevents that. Note that cleaning up // NAT state here takes care of the case where we did not send goodbyes at all. if (rr->NATinfo.clientContext) { mDNS_StopNATOperation_internal(m, &rr->NATinfo); rr->NATinfo.clientContext = mDNSNULL; } if (rr->nta) { CancelGetZoneData(m, rr->nta); rr->nta = mDNSNULL; } if (rr->tcp) { DisposeTCPConn(rr->tcp); rr->tcp = mDNSNULL; } } #endif // UNICAST_DISABLED if (RecordType == kDNSRecordTypeUnregistered) LogMsg("mDNS_Deregister_internal: %s already marked kDNSRecordTypeUnregistered", ARDisplayString(m, rr)); else if (RecordType == kDNSRecordTypeDeregistering) { LogMsg("mDNS_Deregister_internal: %s already marked kDNSRecordTypeDeregistering", ARDisplayString(m, rr)); return(mStatus_BadReferenceErr); } // Local-only questions don't get remove events for unique records // We may want to consider changing this code so that we generate local-only question "rmv" // events (and maybe goodbye packets too) for unique records as well as for shared records // Note: If we change the logic for this "if" statement, need to ensure that the code in // CompleteDeregistration() sets the appropriate state variables to gaurantee that "else" // clause will execute here and the record will be cut from the list. if (rr->WakeUp.HMAC.l[0] || (RecordType == kDNSRecordTypeShared && (rr->RequireGoodbye || rr->AnsweredLocalQ))) { verbosedebugf("mDNS_Deregister_internal: Starting deregistration for %s", ARDisplayString(m, rr)); rr->resrec.RecordType = kDNSRecordTypeDeregistering; rr->resrec.rroriginalttl = 0; rr->AnnounceCount = rr->WakeUp.HMAC.l[0] ? WakeupCount : (drt == mDNS_Dereg_rapid) ? 1 : GoodbyeCount; rr->ThisAPInterval = mDNSPlatformOneSecond * 2; rr->LastAPTime = m->timenow - rr->ThisAPInterval; m->LocalRemoveEvents = mDNStrue; if (m->NextScheduledResponse - (m->timenow + mDNSPlatformOneSecond/10) >= 0) m->NextScheduledResponse = (m->timenow + mDNSPlatformOneSecond/10); } else { if (!dupList && RRLocalOnly(rr)) { AuthGroup *ag = RemoveAuthRecord(m, &m->rrauth, rr); if (ag->NewLocalOnlyRecords == rr) ag->NewLocalOnlyRecords = rr->next; } else { *p = rr->next; // Cut this record from the list if (m->NewLocalRecords == rr) m->NewLocalRecords = rr->next; DecrementAutoTargetServices(m, rr); } // If someone is about to look at this, bump the pointer forward if (m->CurrentRecord == rr) m->CurrentRecord = rr->next; rr->next = mDNSNULL; // Should we generate local remove events here? // i.e. something like: // if (rr->AnsweredLocalQ) { AnswerAllLocalQuestionsWithLocalAuthRecord(m, rr, mDNSfalse); rr->AnsweredLocalQ = mDNSfalse; } verbosedebugf("mDNS_Deregister_internal: Deleting record for %s", ARDisplayString(m, rr)); rr->resrec.RecordType = kDNSRecordTypeUnregistered; if ((drt == mDNS_Dereg_conflict || drt == mDNS_Dereg_repeat) && RecordType == kDNSRecordTypeShared) debugf("mDNS_Deregister_internal: Cannot have a conflict on a shared record! %##s (%s)", rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); // If we have an update queued up which never executed, give the client a chance to free that memory if (rr->NewRData) CompleteRDataUpdate(m, rr); // Update our rdata, clear the NewRData pointer, and return memory to the client // CAUTION: MUST NOT do anything more with rr after calling rr->Callback(), because the client's callback function // is allowed to do anything, including starting/stopping queries, registering/deregistering records, etc. // In this case the likely client action to the mStatus_MemFree message is to free the memory, // so any attempt to touch rr after this is likely to lead to a crash. if (drt != mDNS_Dereg_conflict) { mDNS_DropLockBeforeCallback(); // Allow client to legally make mDNS API calls from the callback LogInfo("mDNS_Deregister_internal: callback with mStatus_MemFree for %s", ARDisplayString(m, rr)); if (rr->RecordCallback) rr->RecordCallback(m, rr, mStatus_MemFree); // MUST NOT touch rr after this mDNS_ReclaimLockAfterCallback(); // Decrement mDNS_reentrancy to block mDNS API calls again } else { RecordProbeFailure(m, rr); mDNS_DropLockBeforeCallback(); // Allow client to legally make mDNS API calls from the callback if (rr->RecordCallback) rr->RecordCallback(m, rr, mStatus_NameConflict); // MUST NOT touch rr after this mDNS_ReclaimLockAfterCallback(); // Decrement mDNS_reentrancy to block mDNS API calls again // Now that we've finished deregistering rr, check our DuplicateRecords list for any that we marked previously. // Note that with all the client callbacks going on, by the time we get here all the // records we marked may have been explicitly deregistered by the client anyway. r2 = m->DuplicateRecords; while (r2) { if (r2->ProbeCount != 0xFF) { r2 = r2->next; } else { #if APPLE_OSX_mDNSResponder // See if this record was also registered with any D2D plugins. D2D_stop_advertising_record(r2); #endif mDNS_Deregister_internal(m, r2, mDNS_Dereg_conflict); // As this is a duplicate record, it will be unlinked from the list // immediately r2 = m->DuplicateRecords; } } } } mDNS_UpdateAllowSleep(m); return(mStatus_NoError); } // *************************************************************************** #if COMPILER_LIKES_PRAGMA_MARK #pragma mark - #pragma mark - Packet Sending Functions #endif mDNSlocal void AddRecordToResponseList(AuthRecord ***nrpp, AuthRecord *rr, AuthRecord *add) { if (rr->NextResponse == mDNSNULL && *nrpp != &rr->NextResponse) { **nrpp = rr; // NR_AdditionalTo must point to a record with NR_AnswerTo set (and not NR_AdditionalTo) // If 'add' does not meet this requirement, then follow its NR_AdditionalTo pointer to a record that does // The referenced record will definitely be acceptable (by recursive application of this rule) if (add && add->NR_AdditionalTo) add = add->NR_AdditionalTo; rr->NR_AdditionalTo = add; *nrpp = &rr->NextResponse; } debugf("AddRecordToResponseList: %##s (%s) already in list", rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); } mDNSlocal void AddRRSetAdditionalsToResponseList(mDNS *const m, AuthRecord ***nrpp, AuthRecord *rr, AuthRecord *additional, const mDNSInterfaceID InterfaceID) { AuthRecord *rr2; if (additional->resrec.RecordType & kDNSRecordTypeUniqueMask) { for (rr2 = m->ResourceRecords; rr2; rr2 = rr2->next) { if ((rr2->resrec.namehash == additional->resrec.namehash) && (rr2->resrec.rrtype == additional->resrec.rrtype) && (rr2 != additional) && (rr2->resrec.RecordType & kDNSRecordTypeUniqueMask) && (rr2->resrec.rrclass == additional->resrec.rrclass) && ResourceRecordIsValidInterfaceAnswer(rr2, InterfaceID) && SameDomainName(rr2->resrec.name, additional->resrec.name)) { AddRecordToResponseList(nrpp, rr2, rr); } } } } mDNSlocal void AddAdditionalsToResponseList(mDNS *const m, AuthRecord *ResponseRecords, AuthRecord ***nrpp, const mDNSInterfaceID InterfaceID) { AuthRecord *rr, *rr2; for (rr=ResponseRecords; rr; rr=rr->NextResponse) // For each record we plan to put { // (Note: This is an "if", not a "while". If we add a record, we'll find it again // later in the "for" loop, and we will follow further "additional" links then.) if (rr->Additional1 && ResourceRecordIsValidInterfaceAnswer(rr->Additional1, InterfaceID)) { AddRecordToResponseList(nrpp, rr->Additional1, rr); AddRRSetAdditionalsToResponseList(m, nrpp, rr, rr->Additional1, InterfaceID); } if (rr->Additional2 && ResourceRecordIsValidInterfaceAnswer(rr->Additional2, InterfaceID)) { AddRecordToResponseList(nrpp, rr->Additional2, rr); AddRRSetAdditionalsToResponseList(m, nrpp, rr, rr->Additional2, InterfaceID); } // For SRV records, automatically add the Address record(s) for the target host if (rr->resrec.rrtype == kDNSType_SRV) { for (rr2=m->ResourceRecords; rr2; rr2=rr2->next) // Scan list of resource records if (RRTypeIsAddressType(rr2->resrec.rrtype) && // For all address records (A/AAAA) ... ResourceRecordIsValidInterfaceAnswer(rr2, InterfaceID) && // ... which are valid for answer ... rr->resrec.rdatahash == rr2->resrec.namehash && // ... whose name is the name of the SRV target SameDomainName(&rr->resrec.rdata->u.srv.target, rr2->resrec.name)) AddRecordToResponseList(nrpp, rr2, rr); } else if (RRTypeIsAddressType(rr->resrec.rrtype)) // For A or AAAA, put counterpart as additional { for (rr2=m->ResourceRecords; rr2; rr2=rr2->next) // Scan list of resource records if (RRTypeIsAddressType(rr2->resrec.rrtype) && // For all address records (A/AAAA) ... ResourceRecordIsValidInterfaceAnswer(rr2, InterfaceID) && // ... which are valid for answer ... rr->resrec.namehash == rr2->resrec.namehash && // ... and have the same name SameDomainName(rr->resrec.name, rr2->resrec.name)) AddRecordToResponseList(nrpp, rr2, rr); } else if (rr->resrec.rrtype == kDNSType_PTR) // For service PTR, see if we want to add DeviceInfo record { if (ResourceRecordIsValidInterfaceAnswer(&m->DeviceInfo, InterfaceID) && SameDomainLabel(rr->resrec.rdata->u.name.c, m->DeviceInfo.resrec.name->c)) AddRecordToResponseList(nrpp, &m->DeviceInfo, rr); } } } mDNSlocal int AnonInfoSpace(AnonymousInfo *info) { ResourceRecord *rr = info->nsec3RR; // 2 bytes for compressed name + type (2) class (2) TTL (4) rdlength (2) rdata (n) return (2 + 10 + rr->rdlength); } mDNSlocal void SendDelayedUnicastResponse(mDNS *const m, const mDNSAddr *const dest, const mDNSInterfaceID InterfaceID) { AuthRecord *rr; AuthRecord *ResponseRecords = mDNSNULL; AuthRecord **nrp = &ResponseRecords; NetworkInterfaceInfo *intf = FirstInterfaceForID(m, InterfaceID); int AnoninfoSpace = 0; // Make a list of all our records that need to be unicast to this destination for (rr = m->ResourceRecords; rr; rr=rr->next) { // If we find we can no longer unicast this answer, clear ImmedUnicast if (rr->ImmedAnswer == mDNSInterfaceMark || mDNSSameIPv4Address(rr->v4Requester, onesIPv4Addr) || mDNSSameIPv6Address(rr->v6Requester, onesIPv6Addr) ) rr->ImmedUnicast = mDNSfalse; if (rr->ImmedUnicast && rr->ImmedAnswer == InterfaceID) { if ((dest->type == mDNSAddrType_IPv4 && mDNSSameIPv4Address(rr->v4Requester, dest->ip.v4)) || (dest->type == mDNSAddrType_IPv6 && mDNSSameIPv6Address(rr->v6Requester, dest->ip.v6))) { rr->ImmedAnswer = mDNSNULL; // Clear the state fields rr->ImmedUnicast = mDNSfalse; rr->v4Requester = zerov4Addr; rr->v6Requester = zerov6Addr; // Only sent records registered for P2P over P2P interfaces if (intf && !mDNSPlatformValidRecordForInterface(rr, intf->InterfaceID)) { continue; } if (rr->NextResponse == mDNSNULL && nrp != &rr->NextResponse) // rr->NR_AnswerTo { rr->NR_AnswerTo = NR_AnswerMulticast; *nrp = rr; nrp = &rr->NextResponse; } } } } AddAdditionalsToResponseList(m, ResponseRecords, &nrp, InterfaceID); while (ResponseRecords) { mDNSu8 *responseptr = m->omsg.data; mDNSu8 *newptr; InitializeDNSMessage(&m->omsg.h, zeroID, ResponseFlags); // Put answers in the packet while (ResponseRecords && ResponseRecords->NR_AnswerTo) { rr = ResponseRecords; if (rr->resrec.AnonInfo) { AnoninfoSpace += AnonInfoSpace(rr->resrec.AnonInfo); rr->resrec.AnonInfo->SendNow = mDNSInterfaceMark; } if (rr->resrec.RecordType & kDNSRecordTypeUniqueMask) rr->resrec.rrclass |= kDNSClass_UniqueRRSet; // Temporarily set the cache flush bit so PutResourceRecord will set it // Retract the limit by AnoninfoSpace which we need to put the AnoInfo option. newptr = PutResourceRecordTTLWithLimit(&m->omsg, responseptr, &m->omsg.h.numAnswers, &rr->resrec, rr->resrec.rroriginalttl, m->omsg.data + (AllowedRRSpace(&m->omsg) - AnoninfoSpace)); rr->resrec.rrclass &= ~kDNSClass_UniqueRRSet; // Make sure to clear cache flush bit back to normal state if (!newptr && m->omsg.h.numAnswers) { break; // If packet full, send it now } if (newptr) responseptr = newptr; ResponseRecords = rr->NextResponse; rr->NextResponse = mDNSNULL; rr->NR_AnswerTo = mDNSNULL; rr->NR_AdditionalTo = mDNSNULL; rr->RequireGoodbye = mDNStrue; } // We have reserved the space for AnonInfo option. PutResourceRecord uses the // standard limit (AllowedRRSpace) and we should have space now. for (rr = m->ResourceRecords; rr; rr=rr->next) { if (rr->resrec.AnonInfo && rr->resrec.AnonInfo->SendNow == mDNSInterfaceMark) { ResourceRecord *nsec3RR = rr->resrec.AnonInfo->nsec3RR; newptr = PutResourceRecord(&m->omsg, responseptr, &m->omsg.h.numAuthorities, nsec3RR); if (newptr) { responseptr = newptr; debugf("SendDelayedUnicastResponse: Added NSEC3 Record %s on %p", RRDisplayString(m, nsec3RR), intf->InterfaceID); } else { // We allocated space and we should not fail. Don't break, we need to clear the SendNow flag. LogMsg("SendDelayedUnicastResponse: ERROR!! Cannot Add NSEC3 Record %s on %p", RRDisplayString(m, nsec3RR), intf->InterfaceID); } rr->resrec.AnonInfo->SendNow = mDNSNULL; } } // Add additionals, if there's space while (ResponseRecords && !ResponseRecords->NR_AnswerTo) { rr = ResponseRecords; if (rr->resrec.RecordType & kDNSRecordTypeUniqueMask) rr->resrec.rrclass |= kDNSClass_UniqueRRSet; // Temporarily set the cache flush bit so PutResourceRecord will set it newptr = PutResourceRecord(&m->omsg, responseptr, &m->omsg.h.numAdditionals, &rr->resrec); rr->resrec.rrclass &= ~kDNSClass_UniqueRRSet; // Make sure to clear cache flush bit back to normal state if (newptr) responseptr = newptr; if (newptr && m->omsg.h.numAnswers) rr->RequireGoodbye = mDNStrue; else if (rr->resrec.RecordType & kDNSRecordTypeUniqueMask) rr->ImmedAnswer = mDNSInterfaceMark; ResponseRecords = rr->NextResponse; rr->NextResponse = mDNSNULL; rr->NR_AnswerTo = mDNSNULL; rr->NR_AdditionalTo = mDNSNULL; } if (m->omsg.h.numAnswers) mDNSSendDNSMessage(m, &m->omsg, responseptr, InterfaceID, mDNSNULL, dest, MulticastDNSPort, mDNSNULL, mDNSNULL, mDNSfalse); } } // CompleteDeregistration guarantees that on exit the record will have been cut from the m->ResourceRecords list // and the client's mStatus_MemFree callback will have been invoked mDNSexport void CompleteDeregistration(mDNS *const m, AuthRecord *rr) { LogInfo("CompleteDeregistration: called for Resource record %s", ARDisplayString(m, rr)); // Clearing rr->RequireGoodbye signals mDNS_Deregister_internal() that // it should go ahead and immediately dispose of this registration rr->resrec.RecordType = kDNSRecordTypeShared; rr->RequireGoodbye = mDNSfalse; rr->WakeUp.HMAC = zeroEthAddr; if (rr->AnsweredLocalQ) { AnswerAllLocalQuestionsWithLocalAuthRecord(m, rr, mDNSfalse); rr->AnsweredLocalQ = mDNSfalse; } mDNS_Deregister_internal(m, rr, mDNS_Dereg_normal); // Don't touch rr after this } // DiscardDeregistrations is used on shutdown and sleep to discard (forcibly and immediately) // any deregistering records that remain in the m->ResourceRecords list. // DiscardDeregistrations calls mDNS_Deregister_internal which can call a user callback, // which may change the record list and/or question list. // Any code walking either list must use the CurrentQuestion and/or CurrentRecord mechanism to protect against this. mDNSlocal void DiscardDeregistrations(mDNS *const m) { if (m->CurrentRecord) LogMsg("DiscardDeregistrations ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); m->CurrentRecord = m->ResourceRecords; while (m->CurrentRecord) { AuthRecord *rr = m->CurrentRecord; if (!AuthRecord_uDNS(rr) && rr->resrec.RecordType == kDNSRecordTypeDeregistering) CompleteDeregistration(m, rr); // Don't touch rr after this else m->CurrentRecord = rr->next; } } mDNSlocal mStatus GetLabelDecimalValue(const mDNSu8 *const src, mDNSu8 *dst) { int i, val = 0; if (src[0] < 1 || src[0] > 3) return(mStatus_Invalid); for (i=1; i<=src[0]; i++) { if (src[i] < '0' || src[i] > '9') return(mStatus_Invalid); val = val * 10 + src[i] - '0'; } if (val > 255) return(mStatus_Invalid); *dst = (mDNSu8)val; return(mStatus_NoError); } mDNSlocal mStatus GetIPv4FromName(mDNSAddr *const a, const domainname *const name) { int skip = CountLabels(name) - 6; if (skip < 0) { LogMsg("GetIPFromName: Need six labels in IPv4 reverse mapping name %##s", name); return mStatus_Invalid; } if (GetLabelDecimalValue(SkipLeadingLabels(name, skip+3)->c, &a->ip.v4.b[0]) || GetLabelDecimalValue(SkipLeadingLabels(name, skip+2)->c, &a->ip.v4.b[1]) || GetLabelDecimalValue(SkipLeadingLabels(name, skip+1)->c, &a->ip.v4.b[2]) || GetLabelDecimalValue(SkipLeadingLabels(name, skip+0)->c, &a->ip.v4.b[3])) return mStatus_Invalid; a->type = mDNSAddrType_IPv4; return(mStatus_NoError); } #define HexVal(X) ( ((X) >= '0' && (X) <= '9') ? ((X) - '0' ) : \ ((X) >= 'A' && (X) <= 'F') ? ((X) - 'A' + 10) : \ ((X) >= 'a' && (X) <= 'f') ? ((X) - 'a' + 10) : -1) mDNSlocal mStatus GetIPv6FromName(mDNSAddr *const a, const domainname *const name) { int i, h, l; const domainname *n; int skip = CountLabels(name) - 34; if (skip < 0) { LogMsg("GetIPFromName: Need 34 labels in IPv6 reverse mapping name %##s", name); return mStatus_Invalid; } n = SkipLeadingLabels(name, skip); for (i=0; i<16; i++) { if (n->c[0] != 1) return mStatus_Invalid; l = HexVal(n->c[1]); n = (const domainname *)(n->c + 2); if (n->c[0] != 1) return mStatus_Invalid; h = HexVal(n->c[1]); n = (const domainname *)(n->c + 2); if (l<0 || h<0) return mStatus_Invalid; a->ip.v6.b[15-i] = (mDNSu8)((h << 4) | l); } a->type = mDNSAddrType_IPv6; return(mStatus_NoError); } mDNSlocal mDNSs32 ReverseMapDomainType(const domainname *const name) { int skip = CountLabels(name) - 2; if (skip >= 0) { const domainname *suffix = SkipLeadingLabels(name, skip); if (SameDomainName(suffix, (const domainname*)"\x7" "in-addr" "\x4" "arpa")) return mDNSAddrType_IPv4; if (SameDomainName(suffix, (const domainname*)"\x3" "ip6" "\x4" "arpa")) return mDNSAddrType_IPv6; } return(mDNSAddrType_None); } mDNSlocal void SendARP(mDNS *const m, const mDNSu8 op, const AuthRecord *const rr, const mDNSv4Addr *const spa, const mDNSEthAddr *const tha, const mDNSv4Addr *const tpa, const mDNSEthAddr *const dst) { int i; mDNSu8 *ptr = m->omsg.data; NetworkInterfaceInfo *intf = FirstInterfaceForID(m, rr->resrec.InterfaceID); if (!intf) { LogMsg("SendARP: No interface with InterfaceID %p found %s", rr->resrec.InterfaceID, ARDisplayString(m,rr)); return; } // 0x00 Destination address for (i=0; i<6; i++) *ptr++ = dst->b[i]; // 0x06 Source address (Note: Since we don't currently set the BIOCSHDRCMPLT option, BPF will fill in the real interface address for us) for (i=0; i<6; i++) *ptr++ = intf->MAC.b[0]; // 0x0C ARP Ethertype (0x0806) *ptr++ = 0x08; *ptr++ = 0x06; // 0x0E ARP header *ptr++ = 0x00; *ptr++ = 0x01; // Hardware address space; Ethernet = 1 *ptr++ = 0x08; *ptr++ = 0x00; // Protocol address space; IP = 0x0800 *ptr++ = 6; // Hardware address length *ptr++ = 4; // Protocol address length *ptr++ = 0x00; *ptr++ = op; // opcode; Request = 1, Response = 2 // 0x16 Sender hardware address (our MAC address) for (i=0; i<6; i++) *ptr++ = intf->MAC.b[i]; // 0x1C Sender protocol address for (i=0; i<4; i++) *ptr++ = spa->b[i]; // 0x20 Target hardware address for (i=0; i<6; i++) *ptr++ = tha->b[i]; // 0x26 Target protocol address for (i=0; i<4; i++) *ptr++ = tpa->b[i]; // 0x2A Total ARP Packet length 42 bytes mDNSPlatformSendRawPacket(m->omsg.data, ptr, rr->resrec.InterfaceID); } mDNSlocal mDNSu16 CheckSum(const void *const data, mDNSs32 length, mDNSu32 sum) { const mDNSu16 *ptr = data; while (length > 0) { length -= 2; sum += *ptr++; } sum = (sum & 0xFFFF) + (sum >> 16); sum = (sum & 0xFFFF) + (sum >> 16); return(sum != 0xFFFF ? sum : 0); } mDNSlocal mDNSu16 IPv6CheckSum(const mDNSv6Addr *const src, const mDNSv6Addr *const dst, const mDNSu8 protocol, const void *const data, const mDNSu32 length) { IPv6PseudoHeader ph; ph.src = *src; ph.dst = *dst; ph.len.b[0] = length >> 24; ph.len.b[1] = length >> 16; ph.len.b[2] = length >> 8; ph.len.b[3] = length; ph.pro.b[0] = 0; ph.pro.b[1] = 0; ph.pro.b[2] = 0; ph.pro.b[3] = protocol; return CheckSum(&ph, sizeof(ph), CheckSum(data, length, 0)); } mDNSlocal void SendNDP(mDNS *const m, const mDNSu8 op, const mDNSu8 flags, const AuthRecord *const rr, const mDNSv6Addr *const spa, const mDNSEthAddr *const tha, const mDNSv6Addr *const tpa, const mDNSEthAddr *const dst) { int i; mDNSOpaque16 checksum; mDNSu8 *ptr = m->omsg.data; // Some recipient hosts seem to ignore Neighbor Solicitations if the IPv6-layer destination address is not the // appropriate IPv6 solicited node multicast address, so we use that IPv6-layer destination address, even though // at the Ethernet-layer we unicast the packet to the intended target, to avoid wasting network bandwidth. const mDNSv6Addr mc = { { 0xFF,0x02,0x00,0x00, 0,0,0,0, 0,0,0,1, 0xFF,tpa->b[0xD],tpa->b[0xE],tpa->b[0xF] } }; const mDNSv6Addr *const v6dst = (op == NDP_Sol) ? &mc : tpa; NetworkInterfaceInfo *intf = FirstInterfaceForID(m, rr->resrec.InterfaceID); if (!intf) { LogMsg("SendNDP: No interface with InterfaceID %p found %s", rr->resrec.InterfaceID, ARDisplayString(m,rr)); return; } // 0x00 Destination address for (i=0; i<6; i++) *ptr++ = dst->b[i]; // Right now we only send Neighbor Solicitations to verify whether the host we're proxying for has gone to sleep yet. // Since we know who we're looking for, we send it via Ethernet-layer unicast, rather than bothering every host on the // link with a pointless link-layer multicast. // Should we want to send traditional Neighbor Solicitations in the future, where we really don't know in advance what // Ethernet-layer address we're looking for, we'll need to send to the appropriate Ethernet-layer multicast address: // *ptr++ = 0x33; // *ptr++ = 0x33; // *ptr++ = 0xFF; // *ptr++ = tpa->b[0xD]; // *ptr++ = tpa->b[0xE]; // *ptr++ = tpa->b[0xF]; // 0x06 Source address (Note: Since we don't currently set the BIOCSHDRCMPLT option, BPF will fill in the real interface address for us) for (i=0; i<6; i++) *ptr++ = (tha ? *tha : intf->MAC).b[i]; // 0x0C IPv6 Ethertype (0x86DD) *ptr++ = 0x86; *ptr++ = 0xDD; // 0x0E IPv6 header *ptr++ = 0x60; *ptr++ = 0x00; *ptr++ = 0x00; *ptr++ = 0x00; // Version, Traffic Class, Flow Label *ptr++ = 0x00; *ptr++ = 0x20; // Length *ptr++ = 0x3A; // Protocol == ICMPv6 *ptr++ = 0xFF; // Hop Limit // 0x16 Sender IPv6 address for (i=0; i<16; i++) *ptr++ = spa->b[i]; // 0x26 Destination IPv6 address for (i=0; i<16; i++) *ptr++ = v6dst->b[i]; // 0x36 NDP header *ptr++ = op; // 0x87 == Neighbor Solicitation, 0x88 == Neighbor Advertisement *ptr++ = 0x00; // Code *ptr++ = 0x00; *ptr++ = 0x00; // Checksum placeholder (0x38, 0x39) *ptr++ = flags; *ptr++ = 0x00; *ptr++ = 0x00; *ptr++ = 0x00; if (op == NDP_Sol) // Neighbor Solicitation. The NDP "target" is the address we seek. { // 0x3E NDP target. for (i=0; i<16; i++) *ptr++ = tpa->b[i]; // 0x4E Source Link-layer Address // // MUST NOT be included when the source IP address is the unspecified address. // Otherwise, on link layers that have addresses this option MUST be included // in multicast solicitations and SHOULD be included in unicast solicitations. if (!mDNSIPv6AddressIsZero(*spa)) { *ptr++ = NDP_SrcLL; // Option Type 1 == Source Link-layer Address *ptr++ = 0x01; // Option length 1 (in units of 8 octets) for (i=0; i<6; i++) *ptr++ = (tha ? *tha : intf->MAC).b[i]; } } else // Neighbor Advertisement. The NDP "target" is the address we're giving information about. { // 0x3E NDP target. for (i=0; i<16; i++) *ptr++ = spa->b[i]; // 0x4E Target Link-layer Address *ptr++ = NDP_TgtLL; // Option Type 2 == Target Link-layer Address *ptr++ = 0x01; // Option length 1 (in units of 8 octets) for (i=0; i<6; i++) *ptr++ = (tha ? *tha : intf->MAC).b[i]; } // 0x4E or 0x56 Total NDP Packet length 78 or 86 bytes m->omsg.data[0x13] = ptr - &m->omsg.data[0x36]; // Compute actual length checksum.NotAnInteger = ~IPv6CheckSum(spa, v6dst, 0x3A, &m->omsg.data[0x36], m->omsg.data[0x13]); m->omsg.data[0x38] = checksum.b[0]; m->omsg.data[0x39] = checksum.b[1]; mDNSPlatformSendRawPacket(m->omsg.data, ptr, rr->resrec.InterfaceID); } mDNSlocal void SetupTracerOpt(const mDNS *const m, rdataOPT *const Trace) { mDNSu32 DNS_VERS = _DNS_SD_H; Trace->u.tracer.platf = m->mDNS_plat; Trace->u.tracer.mDNSv = DNS_VERS; Trace->opt = kDNSOpt_Trace; Trace->optlen = DNSOpt_TraceData_Space - 4; } mDNSlocal void SetupOwnerOpt(const mDNS *const m, const NetworkInterfaceInfo *const intf, rdataOPT *const owner) { owner->u.owner.vers = 0; owner->u.owner.seq = m->SleepSeqNum; owner->u.owner.HMAC = m->PrimaryMAC; owner->u.owner.IMAC = intf->MAC; owner->u.owner.password = zeroEthAddr; // Don't try to compute the optlen until *after* we've set up the data fields // Right now the DNSOpt_Owner_Space macro does not depend on the owner->u.owner being set up correctly, but in the future it might owner->opt = kDNSOpt_Owner; owner->optlen = DNSOpt_Owner_Space(&m->PrimaryMAC, &intf->MAC) - 4; } mDNSlocal void GrantUpdateCredit(AuthRecord *rr) { if (++rr->UpdateCredits >= kMaxUpdateCredits) rr->NextUpdateCredit = 0; else rr->NextUpdateCredit = NonZeroTime(rr->NextUpdateCredit + kUpdateCreditRefreshInterval); } mDNSlocal mDNSBool ShouldSendGoodbyesBeforeSleep(mDNS *const m, const NetworkInterfaceInfo *intf, AuthRecord *rr) { // If there are no sleep proxies, we set the state to SleepState_Sleeping explicitly // and hence there is no need to check for Transfering state. But if we have sleep // proxies and partially sending goodbyes for some records, we will be in Transfering // state and hence need to make sure that we send goodbyes in that case too. Checking whether // we are not awake handles both cases. if ((rr->AuthFlags & AuthFlagsWakeOnly) && (m->SleepState != SleepState_Awake)) { debugf("ShouldSendGoodbyesBeforeSleep: marking for goodbye", ARDisplayString(m, rr)); return mDNStrue; } if (m->SleepState != SleepState_Sleeping) return mDNSfalse; // If we are going to sleep and in SleepState_Sleeping, SendGoodbyes on the interface tell you // whether you can send goodbyes or not. if (!intf->SendGoodbyes) { debugf("ShouldSendGoodbyesBeforeSleep: not sending goodbye %s, int %p", ARDisplayString(m, rr), intf->InterfaceID); return mDNSfalse; } else { debugf("ShouldSendGoodbyesBeforeSleep: sending goodbye %s, int %p", ARDisplayString(m, rr), intf->InterfaceID); return mDNStrue; } } mDNSlocal mDNSBool IsInterfaceValidForAuthRecord(const AuthRecord *ar, mDNSInterfaceID InterfaceID) { mDNSBool result; if (ar->resrec.InterfaceID == mDNSInterface_Any) { result = mDNSPlatformValidRecordForInterface(ar, InterfaceID); } else { result = (ar->resrec.InterfaceID == InterfaceID); } return(result); } // Note about acceleration of announcements to facilitate automatic coalescing of // multiple independent threads of announcements into a single synchronized thread: // The announcements in the packet may be at different stages of maturity; // One-second interval, two-second interval, four-second interval, and so on. // After we've put in all the announcements that are due, we then consider // whether there are other nearly-due announcements that are worth accelerating. // To be eligible for acceleration, a record MUST NOT be older (further along // its timeline) than the most mature record we've already put in the packet. // In other words, younger records can have their timelines accelerated to catch up // with their elder bretheren; this narrows the age gap and helps them eventually get in sync. // Older records cannot have their timelines accelerated; this would just widen // the gap between them and their younger bretheren and get them even more out of sync. // Note: SendResponses calls mDNS_Deregister_internal which can call a user callback, which may change // the record list and/or question list. // Any code walking either list must use the CurrentQuestion and/or CurrentRecord mechanism to protect against this. mDNSlocal void SendResponses(mDNS *const m) { int pktcount = 0; AuthRecord *rr, *r2; mDNSs32 maxExistingAnnounceInterval = 0; const NetworkInterfaceInfo *intf = GetFirstActiveInterface(m->HostInterfaces); m->NextScheduledResponse = m->timenow + FutureTime; if (m->SleepState == SleepState_Transferring) RetrySPSRegistrations(m); for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->ImmedUnicast) { mDNSAddr v4 = { mDNSAddrType_IPv4, {{{0}}} }; mDNSAddr v6 = { mDNSAddrType_IPv6, {{{0}}} }; v4.ip.v4 = rr->v4Requester; v6.ip.v6 = rr->v6Requester; if (!mDNSIPv4AddressIsZero(rr->v4Requester)) SendDelayedUnicastResponse(m, &v4, rr->ImmedAnswer); if (!mDNSIPv6AddressIsZero(rr->v6Requester)) SendDelayedUnicastResponse(m, &v6, rr->ImmedAnswer); if (rr->ImmedUnicast) { LogMsg("SendResponses: ERROR: rr->ImmedUnicast still set: %s", ARDisplayString(m, rr)); rr->ImmedUnicast = mDNSfalse; } } // *** // *** 1. Setup: Set the SendRNow and ImmedAnswer fields to indicate which interface(s) the records need to be sent on // *** // Run through our list of records, and decide which ones we're going to announce on all interfaces for (rr = m->ResourceRecords; rr; rr=rr->next) { while (rr->NextUpdateCredit && m->timenow - rr->NextUpdateCredit >= 0) GrantUpdateCredit(rr); if (TimeToAnnounceThisRecord(rr, m->timenow)) { if (rr->resrec.RecordType == kDNSRecordTypeDeregistering) { if (!rr->WakeUp.HMAC.l[0]) { if (rr->AnnounceCount) rr->ImmedAnswer = mDNSInterfaceMark; // Send goodbye packet on all interfaces } else { mDNSBool unicastOnly; LogSPS("SendResponses: Sending wakeup %2d for %.6a %s", rr->AnnounceCount-3, &rr->WakeUp.IMAC, ARDisplayString(m, rr)); unicastOnly = ((rr->AnnounceCount == WakeupCount) || (rr->AnnounceCount == WakeupCount - 1)) ? mDNStrue : mDNSfalse; SendWakeup(m, rr->resrec.InterfaceID, &rr->WakeUp.IMAC, &rr->WakeUp.password, unicastOnly); for (r2 = rr; r2; r2=r2->next) if ((r2->resrec.RecordType == kDNSRecordTypeDeregistering) && r2->AnnounceCount && (r2->resrec.InterfaceID == rr->resrec.InterfaceID) && mDNSSameEthAddress(&r2->WakeUp.IMAC, &rr->WakeUp.IMAC) && !mDNSSameEthAddress(&zeroEthAddr, &r2->WakeUp.HMAC)) { // For now we only want to send a single Unsolicited Neighbor Advertisement restoring the address to the original // owner, because these packets can cause some IPv6 stacks to falsely conclude that there's an address conflict. if (r2->AddressProxy.type == mDNSAddrType_IPv6 && r2->AnnounceCount == WakeupCount) { LogSPS("NDP Announcement %2d Releasing traffic for H-MAC %.6a I-MAC %.6a %s", r2->AnnounceCount-3, &r2->WakeUp.HMAC, &r2->WakeUp.IMAC, ARDisplayString(m,r2)); SendNDP(m, NDP_Adv, NDP_Override, r2, &r2->AddressProxy.ip.v6, &r2->WakeUp.IMAC, &AllHosts_v6, &AllHosts_v6_Eth); } r2->LastAPTime = m->timenow; // After 15 wakeups without success (maybe host has left the network) send three goodbyes instead if (--r2->AnnounceCount <= GoodbyeCount) r2->WakeUp.HMAC = zeroEthAddr; } } } else if (ResourceRecordIsValidAnswer(rr)) { if (rr->AddressProxy.type) { if (!mDNSSameEthAddress(&zeroEthAddr, &rr->WakeUp.HMAC)) { rr->AnnounceCount--; rr->ThisAPInterval *= 2; rr->LastAPTime = m->timenow; if (rr->AddressProxy.type == mDNSAddrType_IPv4) { LogSPS("ARP Announcement %2d Capturing traffic for H-MAC %.6a I-MAC %.6a %s", rr->AnnounceCount, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, ARDisplayString(m,rr)); SendARP(m, 1, rr, &rr->AddressProxy.ip.v4, &zeroEthAddr, &rr->AddressProxy.ip.v4, &onesEthAddr); } else if (rr->AddressProxy.type == mDNSAddrType_IPv6) { LogSPS("NDP Announcement %2d Capturing traffic for H-MAC %.6a I-MAC %.6a %s", rr->AnnounceCount, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, ARDisplayString(m,rr)); SendNDP(m, NDP_Adv, NDP_Override, rr, &rr->AddressProxy.ip.v6, mDNSNULL, &AllHosts_v6, &AllHosts_v6_Eth); } } } else { rr->ImmedAnswer = mDNSInterfaceMark; // Send on all interfaces if (maxExistingAnnounceInterval < rr->ThisAPInterval) maxExistingAnnounceInterval = rr->ThisAPInterval; if (rr->UpdateBlocked) rr->UpdateBlocked = 0; } } } } // Any interface-specific records we're going to send are marked as being sent on all appropriate interfaces (which is just one) // Eligible records that are more than half-way to their announcement time are accelerated for (rr = m->ResourceRecords; rr; rr=rr->next) if ((rr->resrec.InterfaceID && rr->ImmedAnswer) || (rr->ThisAPInterval <= maxExistingAnnounceInterval && TimeToAnnounceThisRecord(rr, m->timenow + rr->ThisAPInterval/2) && !rr->AddressProxy.type && // Don't include ARP Annoucements when considering which records to accelerate ResourceRecordIsValidAnswer(rr))) rr->ImmedAnswer = mDNSInterfaceMark; // Send on all interfaces // When sending SRV records (particularly when announcing a new service) automatically add related Address record(s) as additionals // Note: Currently all address records are interface-specific, so it's safe to set ImmedAdditional to their InterfaceID, // which will be non-null. If by some chance there is an address record that's not interface-specific (should never happen) // then all that means is that it won't get sent -- which would not be the end of the world. for (rr = m->ResourceRecords; rr; rr=rr->next) { if (rr->ImmedAnswer && rr->resrec.rrtype == kDNSType_SRV) for (r2=m->ResourceRecords; r2; r2=r2->next) // Scan list of resource records if (RRTypeIsAddressType(r2->resrec.rrtype) && // For all address records (A/AAAA) ... ResourceRecordIsValidAnswer(r2) && // ... which are valid for answer ... rr->LastMCTime - r2->LastMCTime >= 0 && // ... which we have not sent recently ... rr->resrec.rdatahash == r2->resrec.namehash && // ... whose name is the name of the SRV target SameDomainName(&rr->resrec.rdata->u.srv.target, r2->resrec.name) && (rr->ImmedAnswer == mDNSInterfaceMark || rr->ImmedAnswer == r2->resrec.InterfaceID)) r2->ImmedAdditional = r2->resrec.InterfaceID; // ... then mark this address record for sending too // We also make sure we send the DeviceInfo TXT record too, if necessary // We check for RecordType == kDNSRecordTypeShared because we don't want to tag the // DeviceInfo TXT record onto a goodbye packet (RecordType == kDNSRecordTypeDeregistering). if (rr->ImmedAnswer && rr->resrec.RecordType == kDNSRecordTypeShared && rr->resrec.rrtype == kDNSType_PTR) if (ResourceRecordIsValidAnswer(&m->DeviceInfo) && SameDomainLabel(rr->resrec.rdata->u.name.c, m->DeviceInfo.resrec.name->c)) { if (!m->DeviceInfo.ImmedAnswer) m->DeviceInfo.ImmedAnswer = rr->ImmedAnswer; else m->DeviceInfo.ImmedAnswer = mDNSInterfaceMark; } } // If there's a record which is supposed to be unique that we're going to send, then make sure that we give // the whole RRSet as an atomic unit. That means that if we have any other records with the same name/type/class // then we need to mark them for sending too. Otherwise, if we set the kDNSClass_UniqueRRSet bit on a // record, then other RRSet members that have not been sent recently will get flushed out of client caches. // -- If a record is marked to be sent on a certain interface, make sure the whole set is marked to be sent on that interface // -- If any record is marked to be sent on all interfaces, make sure the whole set is marked to be sent on all interfaces for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->resrec.RecordType & kDNSRecordTypeUniqueMask) { if (rr->ImmedAnswer) // If we're sending this as answer, see that its whole RRSet is similarly marked { for (r2 = m->ResourceRecords; r2; r2=r2->next) { if ((r2->resrec.RecordType & kDNSRecordTypeUniqueMask) && ResourceRecordIsValidAnswer(r2) && (r2->ImmedAnswer != mDNSInterfaceMark) && (r2->ImmedAnswer != rr->ImmedAnswer) && SameResourceRecordSignature(r2, rr) && ((rr->ImmedAnswer == mDNSInterfaceMark) || IsInterfaceValidForAuthRecord(r2, rr->ImmedAnswer))) { r2->ImmedAnswer = !r2->ImmedAnswer ? rr->ImmedAnswer : mDNSInterfaceMark; } } } else if (rr->ImmedAdditional) // If we're sending this as additional, see that its whole RRSet is similarly marked { for (r2 = m->ResourceRecords; r2; r2=r2->next) { if ((r2->resrec.RecordType & kDNSRecordTypeUniqueMask) && ResourceRecordIsValidAnswer(r2) && (r2->ImmedAdditional != rr->ImmedAdditional) && SameResourceRecordSignature(r2, rr) && IsInterfaceValidForAuthRecord(r2, rr->ImmedAdditional)) { r2->ImmedAdditional = rr->ImmedAdditional; } } } } // Now set SendRNow state appropriately for (rr = m->ResourceRecords; rr; rr=rr->next) { if (rr->ImmedAnswer == mDNSInterfaceMark) // Sending this record on all appropriate interfaces { rr->SendRNow = !intf ? mDNSNULL : (rr->resrec.InterfaceID) ? rr->resrec.InterfaceID : intf->InterfaceID; rr->ImmedAdditional = mDNSNULL; // No need to send as additional if sending as answer rr->LastMCTime = m->timenow; rr->LastMCInterface = rr->ImmedAnswer; rr->ProbeRestartCount = 0; // Reset the probe restart count // If we're announcing this record, and it's at least half-way to its ordained time, then consider this announcement done if (TimeToAnnounceThisRecord(rr, m->timenow + rr->ThisAPInterval/2)) { rr->AnnounceCount--; if (rr->resrec.RecordType != kDNSRecordTypeDeregistering) rr->ThisAPInterval *= 2; rr->LastAPTime = m->timenow; debugf("Announcing %##s (%s) %d", rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype), rr->AnnounceCount); } } else if (rr->ImmedAnswer) // Else, just respond to a single query on single interface: { rr->SendRNow = rr->ImmedAnswer; // Just respond on that interface rr->ImmedAdditional = mDNSNULL; // No need to send as additional too rr->LastMCTime = m->timenow; rr->LastMCInterface = rr->ImmedAnswer; } SetNextAnnounceProbeTime(m, rr); //if (rr->SendRNow) LogMsg("%-15.4a %s", &rr->v4Requester, ARDisplayString(m, rr)); } // *** // *** 2. Loop through interface list, sending records as appropriate // *** while (intf) { int OwnerRecordSpace = (m->AnnounceOwner && intf->MAC.l[0]) ? DNSOpt_Header_Space + DNSOpt_Owner_Space(&m->PrimaryMAC, &intf->MAC) : 0; int TraceRecordSpace = (mDNS_McastTracingEnabled && MDNS_TRACER) ? DNSOpt_Header_Space + DNSOpt_TraceData_Space : 0; int numDereg = 0; int numAnnounce = 0; int numAnswer = 0; int AnoninfoSpace = 0; mDNSu8 *responseptr = m->omsg.data; mDNSu8 *newptr; InitializeDNSMessage(&m->omsg.h, zeroID, ResponseFlags); // First Pass. Look for: // 1. Deregistering records that need to send their goodbye packet // 2. Updated records that need to retract their old data // 3. Answers and announcements we need to send for (rr = m->ResourceRecords; rr; rr=rr->next) { // Skip this interface if the record InterfaceID is *Any and the record is not // appropriate for the interface type. if ((rr->SendRNow == intf->InterfaceID) && ((rr->resrec.InterfaceID == mDNSInterface_Any) && !mDNSPlatformValidRecordForInterface(rr, intf->InterfaceID))) { rr->SendRNow = GetNextActiveInterfaceID(intf); } else if (rr->SendRNow == intf->InterfaceID) { RData *OldRData = rr->resrec.rdata; mDNSu16 oldrdlength = rr->resrec.rdlength; mDNSu8 active = (mDNSu8) (rr->resrec.RecordType != kDNSRecordTypeDeregistering && !ShouldSendGoodbyesBeforeSleep(m, intf, rr)); newptr = mDNSNULL; if (rr->NewRData && active) { // See if we should send a courtesy "goodbye" for the old data before we replace it. if (ResourceRecordIsValidAnswer(rr) && rr->resrec.RecordType == kDNSRecordTypeShared && rr->RequireGoodbye) { newptr = PutRR_OS_TTL(responseptr, &m->omsg.h.numAnswers, &rr->resrec, 0); if (newptr) { responseptr = newptr; numDereg++; rr->RequireGoodbye = mDNSfalse; } else continue; // If this packet is already too full to hold the goodbye for this record, skip it for now and we'll retry later } SetNewRData(&rr->resrec, rr->NewRData, rr->newrdlength); } if (rr->resrec.AnonInfo) { int tmp = AnonInfoSpace(rr->resrec.AnonInfo); AnoninfoSpace += tmp; // Adjust OwnerRecordSpace/TraceRecordSpace which is used by PutRR_OS_TTL below so that // we have space to put in the NSEC3 record in the authority section. OwnerRecordSpace += tmp; TraceRecordSpace += tmp; } if (rr->resrec.RecordType & kDNSRecordTypeUniqueMask) rr->resrec.rrclass |= kDNSClass_UniqueRRSet; // Temporarily set the cache flush bit so PutResourceRecord will set it newptr = PutRR_OS_TTL(responseptr, &m->omsg.h.numAnswers, &rr->resrec, active ? rr->resrec.rroriginalttl : 0); rr->resrec.rrclass &= ~kDNSClass_UniqueRRSet; // Make sure to clear cache flush bit back to normal state if (newptr) { responseptr = newptr; rr->RequireGoodbye = active; if (rr->resrec.RecordType == kDNSRecordTypeDeregistering) numDereg++; else if (rr->LastAPTime == m->timenow) numAnnounce++;else numAnswer++; } if (rr->NewRData && active) SetNewRData(&rr->resrec, OldRData, oldrdlength); // The first time through (pktcount==0), if this record is verified unique // (i.e. typically A, AAAA, SRV, TXT and reverse-mapping PTR), set the flag to add an NSEC too. if (!pktcount && active && (rr->resrec.RecordType & kDNSRecordTypeActiveUniqueMask) && !rr->SendNSECNow) rr->SendNSECNow = mDNSInterfaceMark; if (newptr) // If succeeded in sending, advance to next interface { if (rr->resrec.AnonInfo) { debugf("SendResponses: Marking %s, OwnerRecordSpace %d, TraceRecordSpace %d, limit %p", ARDisplayString(m, rr), OwnerRecordSpace, TraceRecordSpace, m->omsg.data + AllowedRRSpace(&m->omsg) - OwnerRecordSpace - TraceRecordSpace); rr->resrec.AnonInfo->SendNow = intf->InterfaceID; } // If sending on all interfaces, go to next interface; else we're finished now if (rr->ImmedAnswer == mDNSInterfaceMark && rr->resrec.InterfaceID == mDNSInterface_Any) rr->SendRNow = GetNextActiveInterfaceID(intf); else rr->SendRNow = mDNSNULL; } } } // Get the reserved space back OwnerRecordSpace -= AnoninfoSpace; TraceRecordSpace -= AnoninfoSpace; newptr = responseptr; for (rr = m->ResourceRecords; rr; rr=rr->next) { if (rr->resrec.AnonInfo && rr->resrec.AnonInfo->SendNow == intf->InterfaceID) { ResourceRecord *nsec3RR = rr->resrec.AnonInfo->nsec3RR; newptr = PutRR_OS_TTL(newptr, &m->omsg.h.numAuthorities, nsec3RR, nsec3RR->rroriginalttl); if (newptr) { responseptr = newptr; debugf("SendResponses: Added NSEC3 %s, OwnerRecordSpace %d, TraceRecordSpace %d, limit %p", ARDisplayString(m, rr), OwnerRecordSpace, TraceRecordSpace, m->omsg.data + AllowedRRSpace(&m->omsg) - OwnerRecordSpace - TraceRecordSpace); } else { LogMsg("SendResponses: Cannot add NSEC3 %s, OwnerRecordSpace %d, TraceRecordSpace %d, limit %p", ARDisplayString(m, rr), OwnerRecordSpace, TraceRecordSpace, m->omsg.data + AllowedRRSpace(&m->omsg) - OwnerRecordSpace - TraceRecordSpace); } rr->resrec.AnonInfo->SendNow = mDNSNULL; } } // Second Pass. Add additional records, if there's space. newptr = responseptr; for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->ImmedAdditional == intf->InterfaceID) if (ResourceRecordIsValidAnswer(rr)) { // If we have at least one answer already in the packet, then plan to add additionals too mDNSBool SendAdditional = (m->omsg.h.numAnswers > 0); // If we're not planning to send any additionals, but this record is a unique one, then // make sure we haven't already sent any other members of its RRSet -- if we have, then they // will have had the cache flush bit set, so now we need to finish the job and send the rest. if (!SendAdditional && (rr->resrec.RecordType & kDNSRecordTypeUniqueMask)) { const AuthRecord *a; for (a = m->ResourceRecords; a; a=a->next) if (a->LastMCTime == m->timenow && a->LastMCInterface == intf->InterfaceID && SameResourceRecordSignature(a, rr)) { SendAdditional = mDNStrue; break; } } if (!SendAdditional) // If we don't want to send this after all, rr->ImmedAdditional = mDNSNULL; // then cancel its ImmedAdditional field else if (newptr) // Else, try to add it if we can { // The first time through (pktcount==0), if this record is verified unique // (i.e. typically A, AAAA, SRV, TXT and reverse-mapping PTR), set the flag to add an NSEC too. if (!pktcount && (rr->resrec.RecordType & kDNSRecordTypeActiveUniqueMask) && !rr->SendNSECNow) rr->SendNSECNow = mDNSInterfaceMark; if (rr->resrec.RecordType & kDNSRecordTypeUniqueMask) rr->resrec.rrclass |= kDNSClass_UniqueRRSet; // Temporarily set the cache flush bit so PutResourceRecord will set it newptr = PutRR_OS(newptr, &m->omsg.h.numAdditionals, &rr->resrec); rr->resrec.rrclass &= ~kDNSClass_UniqueRRSet; // Make sure to clear cache flush bit back to normal state if (newptr) { responseptr = newptr; rr->ImmedAdditional = mDNSNULL; rr->RequireGoodbye = mDNStrue; // If we successfully put this additional record in the packet, we record LastMCTime & LastMCInterface. // This matters particularly in the case where we have more than one IPv6 (or IPv4) address, because otherwise, // when we see our own multicast with the cache flush bit set, if we haven't set LastMCTime, then we'll get // all concerned and re-announce our record again to make sure it doesn't get flushed from peer caches. rr->LastMCTime = m->timenow; rr->LastMCInterface = intf->InterfaceID; } } } // Third Pass. Add NSEC records, if there's space. // When we're generating an NSEC record in response to a specify query for that type // (recognized by rr->SendNSECNow == intf->InterfaceID) we should really put the NSEC in the Answer Section, // not Additional Section, but for now it's easier to handle both cases in this Additional Section loop here. for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->SendNSECNow == mDNSInterfaceMark || rr->SendNSECNow == intf->InterfaceID) { AuthRecord nsec; mDNSu8 *ptr; int len; mDNS_SetupResourceRecord(&nsec, mDNSNULL, mDNSInterface_Any, kDNSType_NSEC, rr->resrec.rroriginalttl, kDNSRecordTypeUnique, AuthRecordAny, mDNSNULL, mDNSNULL); nsec.resrec.rrclass |= kDNSClass_UniqueRRSet; AssignDomainName(&nsec.namestorage, rr->resrec.name); ptr = nsec.rdatastorage.u.data; len = DomainNameLength(rr->resrec.name); // We have a nxt name followed by window number, window length and a window bitmap nsec.resrec.rdlength = len + 2 + NSEC_MCAST_WINDOW_SIZE; if (nsec.resrec.rdlength <= StandardAuthRDSize) { mDNSPlatformMemZero(ptr, nsec.resrec.rdlength); AssignDomainName((domainname *)ptr, rr->resrec.name); ptr += len; *ptr++ = 0; // window number *ptr++ = NSEC_MCAST_WINDOW_SIZE; // window length for (r2 = m->ResourceRecords; r2; r2=r2->next) if (ResourceRecordIsValidAnswer(r2) && SameResourceRecordNameClassInterface(r2, rr)) { if (r2->resrec.rrtype >= kDNSQType_ANY) { LogMsg("SendResponses: Can't create NSEC for record %s", ARDisplayString(m, r2)); break; } else ptr[r2->resrec.rrtype >> 3] |= 128 >> (r2->resrec.rrtype & 7); } newptr = responseptr; if (!r2) // If we successfully built our NSEC record, add it to the packet now { newptr = PutRR_OS(responseptr, &m->omsg.h.numAdditionals, &nsec.resrec); if (newptr) responseptr = newptr; } } else LogMsg("SendResponses: not enough space (%d) in authrecord for nsec", nsec.resrec.rdlength); // If we successfully put the NSEC record, clear the SendNSECNow flag // If we consider this NSEC optional, then we unconditionally clear the SendNSECNow flag, even if we fail to put this additional record if (newptr || rr->SendNSECNow == mDNSInterfaceMark) { rr->SendNSECNow = mDNSNULL; // Run through remainder of list clearing SendNSECNow flag for all other records which would generate the same NSEC for (r2 = rr->next; r2; r2=r2->next) if (SameResourceRecordNameClassInterface(r2, rr)) if (r2->SendNSECNow == mDNSInterfaceMark || r2->SendNSECNow == intf->InterfaceID) r2->SendNSECNow = mDNSNULL; } } if (m->omsg.h.numAnswers || m->omsg.h.numAdditionals) { // If we have data to send, add OWNER/TRACER/OWNER+TRACER option if necessary, then send packet if (OwnerRecordSpace || TraceRecordSpace) { AuthRecord opt; mDNS_SetupResourceRecord(&opt, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); opt.resrec.rrclass = NormalMaxDNSMessageData; opt.resrec.rdlength = sizeof(rdataOPT); opt.resrec.rdestimate = sizeof(rdataOPT); if (OwnerRecordSpace && TraceRecordSpace) { opt.resrec.rdlength += sizeof(rdataOPT); // Two options in this OPT record opt.resrec.rdestimate += sizeof(rdataOPT); SetupOwnerOpt(m, intf, &opt.resrec.rdata->u.opt[0]); SetupTracerOpt(m, &opt.resrec.rdata->u.opt[1]); } else if (OwnerRecordSpace) { SetupOwnerOpt(m, intf, &opt.resrec.rdata->u.opt[0]); } else if (TraceRecordSpace) { SetupTracerOpt(m, &opt.resrec.rdata->u.opt[0]); } newptr = PutResourceRecord(&m->omsg, responseptr, &m->omsg.h.numAdditionals, &opt.resrec); if (newptr) { responseptr = newptr; } else if (m->omsg.h.numAnswers + m->omsg.h.numAuthorities + m->omsg.h.numAdditionals == 1) { LogInfo("SendResponses: No space in packet for %s %s OPT record (%d/%d/%d/%d) %s", OwnerRecordSpace ? "OWNER" : "", TraceRecordSpace ? "TRACER" : "", m->omsg.h.numQuestions, m->omsg.h.numAnswers, m->omsg.h.numAuthorities, m->omsg.h.numAdditionals, ARDisplayString(m, &opt)); } else { LogMsg("SendResponses: How did we fail to have space for %s %s OPT record (%d/%d/%d/%d) %s", OwnerRecordSpace ? "OWNER" : "", TraceRecordSpace ? "TRACER" : "", m->omsg.h.numQuestions, m->omsg.h.numAnswers, m->omsg.h.numAuthorities, m->omsg.h.numAdditionals, ARDisplayString(m, &opt)); } } debugf("SendResponses: Sending %d Deregistration%s, %d Announcement%s, %d Answer%s, %d Additional%s on %p", numDereg, numDereg == 1 ? "" : "s", numAnnounce, numAnnounce == 1 ? "" : "s", numAnswer, numAnswer == 1 ? "" : "s", m->omsg.h.numAdditionals, m->omsg.h.numAdditionals == 1 ? "" : "s", intf->InterfaceID); if (intf->IPv4Available) mDNSSendDNSMessage(m, &m->omsg, responseptr, intf->InterfaceID, mDNSNULL, &AllDNSLinkGroup_v4, MulticastDNSPort, mDNSNULL, mDNSNULL, mDNSfalse); if (intf->IPv6Available) mDNSSendDNSMessage(m, &m->omsg, responseptr, intf->InterfaceID, mDNSNULL, &AllDNSLinkGroup_v6, MulticastDNSPort, mDNSNULL, mDNSNULL, mDNSfalse); if (!m->SuppressSending) m->SuppressSending = NonZeroTime(m->timenow + (mDNSPlatformOneSecond+9)/10); if (++pktcount >= 1000) { LogMsg("SendResponses exceeded loop limit %d: giving up", pktcount); break; } // There might be more things to send on this interface, so go around one more time and try again. } else // Nothing more to send on this interface; go to next { const NetworkInterfaceInfo *next = GetFirstActiveInterface(intf->next); #if MDNS_DEBUGMSGS && 0 const char *const msg = next ? "SendResponses: Nothing more on %p; moving to %p" : "SendResponses: Nothing more on %p"; debugf(msg, intf, next); #endif intf = next; pktcount = 0; // When we move to a new interface, reset packet count back to zero -- NSEC generation logic uses it } } // *** // *** 3. Cleanup: Now that everything is sent, call client callback functions, and reset state variables // *** if (m->CurrentRecord) LogMsg("SendResponses ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); m->CurrentRecord = m->ResourceRecords; while (m->CurrentRecord) { rr = m->CurrentRecord; m->CurrentRecord = rr->next; if (rr->SendRNow) { if (rr->ARType != AuthRecordLocalOnly && rr->ARType != AuthRecordP2P) LogInfo("SendResponses: No active interface %d to send: %d %02X %s", IID(rr->SendRNow), IID(rr->resrec.InterfaceID), rr->resrec.RecordType, ARDisplayString(m, rr)); rr->SendRNow = mDNSNULL; } if (rr->ImmedAnswer || rr->resrec.RecordType == kDNSRecordTypeDeregistering) { if (rr->NewRData) CompleteRDataUpdate(m, rr); // Update our rdata, clear the NewRData pointer, and return memory to the client if (rr->resrec.RecordType == kDNSRecordTypeDeregistering && rr->AnnounceCount == 0) { // For Unicast, when we get the response from the server, we will call CompleteDeregistration if (!AuthRecord_uDNS(rr)) CompleteDeregistration(m, rr); // Don't touch rr after this } else { rr->ImmedAnswer = mDNSNULL; rr->ImmedUnicast = mDNSfalse; rr->v4Requester = zerov4Addr; rr->v6Requester = zerov6Addr; } } } verbosedebugf("SendResponses: Next in %ld ticks", m->NextScheduledResponse - m->timenow); } // Calling CheckCacheExpiration() is an expensive operation because it has to look at the entire cache, // so we want to be lazy about how frequently we do it. // 1. If a cache record is currently referenced by *no* active questions, // then we don't mind expiring it up to a minute late (who will know?) // 2. Else, if a cache record is due for some of its final expiration queries, // we'll allow them to be late by up to 2% of the TTL // 3. Else, if a cache record has completed all its final expiration queries without success, // and is expiring, and had an original TTL more than ten seconds, we'll allow it to be one second late // 4. Else, it is expiring and had an original TTL of ten seconds or less (includes explicit goodbye packets), // so allow at most 1/10 second lateness // 5. For records with rroriginalttl set to zero, that means we really want to delete them immediately // (we have a new record with DelayDelivery set, waiting for the old record to go away before we can notify clients). #define CacheCheckGracePeriod(RR) ( \ ((RR)->CRActiveQuestion == mDNSNULL ) ? (60 * mDNSPlatformOneSecond) : \ ((RR)->UnansweredQueries < MaxUnansweredQueries) ? (TicksTTL(rr)/50) : \ ((RR)->resrec.rroriginalttl > 10 ) ? (mDNSPlatformOneSecond) : \ ((RR)->resrec.rroriginalttl > 0 ) ? (mDNSPlatformOneSecond/10) : 0) #define NextCacheCheckEvent(RR) ((RR)->NextRequiredQuery + CacheCheckGracePeriod(RR)) mDNSexport void ScheduleNextCacheCheckTime(mDNS *const m, const mDNSu32 slot, const mDNSs32 event) { if (m->rrcache_nextcheck[slot] - event > 0) m->rrcache_nextcheck[slot] = event; if (m->NextCacheCheck - event > 0) m->NextCacheCheck = event; } // Note: MUST call SetNextCacheCheckTimeForRecord any time we change: // rr->TimeRcvd // rr->resrec.rroriginalttl // rr->UnansweredQueries // rr->CRActiveQuestion mDNSexport void SetNextCacheCheckTimeForRecord(mDNS *const m, CacheRecord *const rr) { rr->NextRequiredQuery = RRExpireTime(rr); // If we have an active question, then see if we want to schedule a refresher query for this record. // Usually we expect to do four queries, at 80-82%, 85-87%, 90-92% and then 95-97% of the TTL. if (rr->CRActiveQuestion && rr->UnansweredQueries < MaxUnansweredQueries) { rr->NextRequiredQuery -= TicksTTL(rr)/20 * (MaxUnansweredQueries - rr->UnansweredQueries); rr->NextRequiredQuery += mDNSRandom((mDNSu32)TicksTTL(rr)/50); verbosedebugf("SetNextCacheCheckTimeForRecord: NextRequiredQuery in %ld sec CacheCheckGracePeriod %d ticks for %s", (rr->NextRequiredQuery - m->timenow) / mDNSPlatformOneSecond, CacheCheckGracePeriod(rr), CRDisplayString(m,rr)); } ScheduleNextCacheCheckTime(m, HashSlotFromNameHash(rr->resrec.namehash), NextCacheCheckEvent(rr)); } #define kMinimumReconfirmTime ((mDNSu32)mDNSPlatformOneSecond * 5) #define kDefaultReconfirmTimeForWake ((mDNSu32)mDNSPlatformOneSecond * 5) #define kDefaultReconfirmTimeForNoAnswer ((mDNSu32)mDNSPlatformOneSecond * 5) // Delay before restarting questions on a flapping interface. #define kDefaultQueryDelayTimeForFlappingInterface ((mDNSu32)mDNSPlatformOneSecond * 3) // After kDefaultQueryDelayTimeForFlappingInterface seconds, allow enough time for up to three queries (0, 1, and 4 seconds) // plus three seconds for "response delay" before removing the reconfirmed records from the cache. #define kDefaultReconfirmTimeForFlappingInterface (kDefaultQueryDelayTimeForFlappingInterface + ((mDNSu32)mDNSPlatformOneSecond * 7)) mDNSexport mStatus mDNS_Reconfirm_internal(mDNS *const m, CacheRecord *const rr, mDNSu32 interval) { if (interval < kMinimumReconfirmTime) interval = kMinimumReconfirmTime; if (interval > 0x10000000) // Make sure interval doesn't overflow when we multiply by four below interval = 0x10000000; // If the expected expiration time for this record is more than interval+33%, then accelerate its expiration if (RRExpireTime(rr) - m->timenow > (mDNSs32)((interval * 4) / 3)) { // Add a 33% random amount to the interval, to avoid synchronization between multiple hosts // For all the reconfirmations in a given batch, we want to use the same random value // so that the reconfirmation questions can be grouped into a single query packet if (!m->RandomReconfirmDelay) m->RandomReconfirmDelay = 1 + mDNSRandom(FutureTime); interval += m->RandomReconfirmDelay % ((interval/3) + 1); rr->TimeRcvd = m->timenow - (mDNSs32)interval * 3; rr->resrec.rroriginalttl = (interval * 4 + mDNSPlatformOneSecond - 1) / mDNSPlatformOneSecond; SetNextCacheCheckTimeForRecord(m, rr); } debugf("mDNS_Reconfirm_internal:%6ld ticks to go for %s %p", RRExpireTime(rr) - m->timenow, CRDisplayString(m, rr), rr->CRActiveQuestion); return(mStatus_NoError); } // BuildQuestion puts a question into a DNS Query packet and if successful, updates the value of queryptr. // It also appends to the list of known answer records that need to be included, // and updates the forcast for the size of the known answer section. mDNSlocal mDNSBool BuildQuestion(mDNS *const m, const NetworkInterfaceInfo *intf, DNSMessage *query, mDNSu8 **queryptr, DNSQuestion *q, CacheRecord ***kalistptrptr, mDNSu32 *answerforecast) { mDNSBool ucast = (q->LargeAnswers || q->RequestUnicast) && m->CanReceiveUnicastOn5353 && intf->SupportsUnicastMDNSResponse; mDNSu16 ucbit = (mDNSu16)(ucast ? kDNSQClass_UnicastResponse : 0); const mDNSu8 *const limit = query->data + NormalMaxDNSMessageData; mDNSu8 anoninfo_space = q->AnonInfo ? AnonInfoSpace(q->AnonInfo) : 0; mDNSu8 *newptr = putQuestion(query, *queryptr, limit - *answerforecast - anoninfo_space, &q->qname, q->qtype, (mDNSu16)(q->qclass | ucbit)); if (!newptr) { debugf("BuildQuestion: No more space in this packet for question %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); return(mDNSfalse); } else { mDNSu32 forecast = *answerforecast + anoninfo_space; const CacheGroup *const cg = CacheGroupForName(m, q->qnamehash, &q->qname); CacheRecord *rr; CacheRecord **ka = *kalistptrptr; // Make a working copy of the pointer we're going to update for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) // If we have a resource record in our cache, if (rr->resrec.InterfaceID == q->SendQNow && // received on this interface !(rr->resrec.RecordType & kDNSRecordTypeUniqueMask) && // which is a shared (i.e. not unique) record type rr->NextInKAList == mDNSNULL && ka != &rr->NextInKAList && // which is not already in the known answer list rr->resrec.rdlength <= SmallRecordLimit && // which is small enough to sensibly fit in the packet SameNameRecordAnswersQuestion(&rr->resrec, q) && // which answers our question rr->TimeRcvd + TicksTTL(rr)/2 - m->timenow > // and its half-way-to-expiry time is at least 1 second away mDNSPlatformOneSecond) // (also ensures we never include goodbye records with TTL=1) { // We don't want to include unique records in the Known Answer section. The Known Answer section // is intended to suppress floods of shared-record replies from many other devices on the network. // That concept really does not apply to unique records, and indeed if we do send a query for // which we have a unique record already in our cache, then including that unique record as a // Known Answer, so as to suppress the only answer we were expecting to get, makes little sense. *ka = rr; // Link this record into our known answer chain ka = &rr->NextInKAList; // We forecast: compressed name (2) type (2) class (2) TTL (4) rdlength (2) rdata (n) forecast += 12 + rr->resrec.rdestimate; // If we're trying to put more than one question in this packet, and it doesn't fit // then undo that last question and try again next time if (query->h.numQuestions > 1 && newptr + forecast >= limit) { query->h.numQuestions--; debugf("BuildQuestion: Retracting question %##s (%s) new forecast total %d, total questions %d", q->qname.c, DNSTypeName(q->qtype), newptr + forecast - query->data, query->h.numQuestions); ka = *kalistptrptr; // Go back to where we started and retract these answer records while (*ka) { CacheRecord *c = *ka; *ka = mDNSNULL; ka = &c->NextInKAList; } return(mDNSfalse); // Return false, so we'll try again in the next packet } } // Success! Update our state pointers, increment UnansweredQueries as appropriate, and return *queryptr = newptr; // Update the packet pointer *answerforecast = forecast; // Update the forecast *kalistptrptr = ka; // Update the known answer list pointer if (ucast) q->ExpectUnicastResp = NonZeroTime(m->timenow); for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) // For every resource record in our cache, if (rr->resrec.InterfaceID == q->SendQNow && // received on this interface rr->NextInKAList == mDNSNULL && ka != &rr->NextInKAList && // which is not in the known answer list SameNameRecordAnswersQuestion(&rr->resrec, q)) // which answers our question { rr->UnansweredQueries++; // indicate that we're expecting a response rr->LastUnansweredTime = m->timenow; SetNextCacheCheckTimeForRecord(m, rr); } return(mDNStrue); } } // When we have a query looking for a specified name, but there appear to be no answers with // that name, ReconfirmAntecedents() is called with depth=0 to start the reconfirmation process // for any records in our cache that reference the given name (e.g. PTR and SRV records). // For any such cache record we find, we also recursively call ReconfirmAntecedents() for *its* name. // We increment depth each time we recurse, to guard against possible infinite loops, with a limit of 5. // A typical reconfirmation scenario might go like this: // Depth 0: Name "myhost.local" has no address records // Depth 1: SRV "My Service._example._tcp.local." refers to "myhost.local"; may be stale // Depth 2: PTR "_example._tcp.local." refers to "My Service"; may be stale // Depth 3: PTR "_services._dns-sd._udp.local." refers to "_example._tcp.local."; may be stale // Currently depths 4 and 5 are not expected to occur; if we did get to depth 5 we'd reconfim any records we // found referring to the given name, but not recursively descend any further reconfirm *their* antecedents. mDNSlocal void ReconfirmAntecedents(mDNS *const m, const domainname *const name, const mDNSu32 namehash, const int depth) { mDNSu32 slot; CacheGroup *cg; CacheRecord *cr; debugf("ReconfirmAntecedents (depth=%d) for %##s", depth, name->c); FORALL_CACHERECORDS(slot, cg, cr) { domainname *crtarget = GetRRDomainNameTarget(&cr->resrec); if (crtarget && cr->resrec.rdatahash == namehash && SameDomainName(crtarget, name)) { LogInfo("ReconfirmAntecedents: Reconfirming (depth=%d) %s", depth, CRDisplayString(m, cr)); mDNS_Reconfirm_internal(m, cr, kDefaultReconfirmTimeForNoAnswer); if (depth < 5) ReconfirmAntecedents(m, cr->resrec.name, cr->resrec.namehash, depth+1); } } } // If we get no answer for a AAAA query, then before doing an automatic implicit ReconfirmAntecedents // we check if we have an address record for the same name. If we do have an IPv4 address for a given // name but not an IPv6 address, that's okay (it just means the device doesn't do IPv6) so the failure // to get a AAAA response is not grounds to doubt the PTR/SRV chain that lead us to that name. mDNSlocal const CacheRecord *CacheHasAddressTypeForName(mDNS *const m, const domainname *const name, const mDNSu32 namehash) { CacheGroup *const cg = CacheGroupForName(m, namehash, name); const CacheRecord *cr = cg ? cg->members : mDNSNULL; while (cr && !RRTypeIsAddressType(cr->resrec.rrtype)) cr=cr->next; return(cr); } mDNSlocal const CacheRecord *FindSPSInCache1(mDNS *const m, const DNSQuestion *const q, const CacheRecord *const c0, const CacheRecord *const c1) { #ifndef SPC_DISABLED CacheGroup *const cg = CacheGroupForName(m, q->qnamehash, &q->qname); const CacheRecord *cr, *bestcr = mDNSNULL; mDNSu32 bestmetric = 1000000; for (cr = cg ? cg->members : mDNSNULL; cr; cr=cr->next) if (cr->resrec.rrtype == kDNSType_PTR && cr->resrec.rdlength >= 6) // If record is PTR type, with long enough name, if (cr != c0 && cr != c1) // that's not one we've seen before, if (SameNameRecordAnswersQuestion(&cr->resrec, q)) // and answers our browse query, if (!IdenticalSameNameRecord(&cr->resrec, &m->SPSRecords.RR_PTR.resrec)) // and is not our own advertised service... { mDNSu32 metric = SPSMetric(cr->resrec.rdata->u.name.c); if (bestmetric > metric) { bestmetric = metric; bestcr = cr; } } return(bestcr); #else // SPC_DISABLED (void) m; (void) q; (void) c0; (void) c1; (void) c1; return mDNSNULL; #endif // SPC_DISABLED } mDNSlocal void CheckAndSwapSPS(const CacheRecord **sps1, const CacheRecord **sps2) { const CacheRecord *swap_sps; mDNSu32 metric1, metric2; if (!(*sps1) || !(*sps2)) return; metric1 = SPSMetric((*sps1)->resrec.rdata->u.name.c); metric2 = SPSMetric((*sps2)->resrec.rdata->u.name.c); if (!SPSFeatures((*sps1)->resrec.rdata->u.name.c) && SPSFeatures((*sps2)->resrec.rdata->u.name.c) && (metric2 >= metric1)) { swap_sps = *sps1; *sps1 = *sps2; *sps2 = swap_sps; } } mDNSlocal void ReorderSPSByFeature(const CacheRecord *sps[3]) { CheckAndSwapSPS(&sps[0], &sps[1]); CheckAndSwapSPS(&sps[0], &sps[2]); CheckAndSwapSPS(&sps[1], &sps[2]); } // Finds the three best Sleep Proxies we currently have in our cache mDNSexport void FindSPSInCache(mDNS *const m, const DNSQuestion *const q, const CacheRecord *sps[3]) { sps[0] = FindSPSInCache1(m, q, mDNSNULL, mDNSNULL); sps[1] = !sps[0] ? mDNSNULL : FindSPSInCache1(m, q, sps[0], mDNSNULL); sps[2] = !sps[1] ? mDNSNULL : FindSPSInCache1(m, q, sps[0], sps[1]); // SPS is already sorted by metric. We want to move the entries to the beginning of the array // only if they have equally good metric and support features. ReorderSPSByFeature(sps); } // Only DupSuppressInfos newer than the specified 'time' are allowed to remain active mDNSlocal void ExpireDupSuppressInfo(DupSuppressInfo ds[DupSuppressInfoSize], mDNSs32 time) { int i; for (i=0; iIPv4Available; // If this interface doesn't do v4, we don't need to find a v4 duplicate of this query mDNSBool v6 = !intf->IPv6Available; // If this interface doesn't do v6, we don't need to find a v6 duplicate of this query for (i=0; iInterfaceID) { if (ds[i].Type == mDNSAddrType_IPv4) v4 = mDNStrue; else if (ds[i].Type == mDNSAddrType_IPv6) v6 = mDNStrue; if (v4 && v6) return(mDNStrue); } return(mDNSfalse); } mDNSlocal void RecordDupSuppressInfo(DupSuppressInfo ds[DupSuppressInfoSize], mDNSs32 Time, mDNSInterfaceID InterfaceID, mDNSs32 Type) { int i, j; // See if we have this one in our list somewhere already for (i=0; i= DupSuppressInfoSize) { i = 0; for (j=1; jInterfaceID; domainname *d = &q->qname; // We can't send magic packets without knowing which interface to send it on. if (InterfaceID == mDNSInterface_Any || LocalOnlyOrP2PInterface(InterfaceID)) { LogMsg("mDNSSendWakeOnResolve: ERROR!! Invalid InterfaceID %p for question %##s", InterfaceID, q->qname.c); return; } // Split MAC@IPAddress and pass them separately len = d->c[0]; cnt = 0; for (i = 1; i < len; i++) { if (d->c[i] == '@') { char EthAddr[18]; // ethernet adddress : 12 bytes + 5 ":" + 1 NULL byte char IPAddr[47]; // Max IP address len: 46 bytes (IPv6) + 1 NULL byte if (cnt != 5) { LogMsg("mDNSSendWakeOnResolve: ERROR!! Malformed Ethernet address %##s, cnt %d", q->qname.c, cnt); return; } if ((i - 1) > (int) (sizeof(EthAddr) - 1)) { LogMsg("mDNSSendWakeOnResolve: ERROR!! Malformed Ethernet address %##s, length %d", q->qname.c, i - 1); return; } if ((len - i) > (int)(sizeof(IPAddr) - 1)) { LogMsg("mDNSSendWakeOnResolve: ERROR!! Malformed IP address %##s, length %d", q->qname.c, len - i); return; } mDNSPlatformMemCopy(EthAddr, &d->c[1], i - 1); EthAddr[i - 1] = 0; mDNSPlatformMemCopy(IPAddr, &d->c[i + 1], len - i); IPAddr[len - i] = 0; m->mDNSStats.WakeOnResolves++; mDNSPlatformSendWakeupPacket(InterfaceID, EthAddr, IPAddr, InitialWakeOnResolveCount - q->WakeOnResolveCount); return; } else if (d->c[i] == ':') cnt++; } LogMsg("mDNSSendWakeOnResolve: ERROR!! Malformed WakeOnResolve name %##s", q->qname.c); } mDNSlocal mDNSBool AccelerateThisQuery(mDNS *const m, DNSQuestion *q) { // If more than 90% of the way to the query time, we should unconditionally accelerate it if (TimeToSendThisQuestion(q, m->timenow + q->ThisQInterval/10)) return(mDNStrue); // If half-way to next scheduled query time, only accelerate if it will add less than 512 bytes to the packet if (TimeToSendThisQuestion(q, m->timenow + q->ThisQInterval/2)) { // We forecast: qname (n) type (2) class (2) mDNSu32 forecast = (mDNSu32)DomainNameLength(&q->qname) + 4; const CacheGroup *const cg = CacheGroupForName(m, q->qnamehash, &q->qname); const CacheRecord *rr; for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) // If we have a resource record in our cache, if (rr->resrec.rdlength <= SmallRecordLimit && // which is small enough to sensibly fit in the packet SameNameRecordAnswersQuestion(&rr->resrec, q) && // which answers our question rr->TimeRcvd + TicksTTL(rr)/2 - m->timenow >= 0 && // and it is less than half-way to expiry rr->NextRequiredQuery - (m->timenow + q->ThisQInterval) > 0) // and we'll ask at least once again before NextRequiredQuery { // We forecast: compressed name (2) type (2) class (2) TTL (4) rdlength (2) rdata (n) forecast += 12 + rr->resrec.rdestimate; if (forecast >= 512) return(mDNSfalse); // If this would add 512 bytes or more to the packet, don't accelerate } return(mDNStrue); } return(mDNSfalse); } // How Standard Queries are generated: // 1. The Question Section contains the question // 2. The Additional Section contains answers we already know, to suppress duplicate responses // How Probe Queries are generated: // 1. The Question Section contains queries for the name we intend to use, with QType=ANY because // if some other host is already using *any* records with this name, we want to know about it. // 2. The Authority Section contains the proposed values we intend to use for one or more // of our records with that name (analogous to the Update section of DNS Update packets) // because if some other host is probing at the same time, we each want to know what the other is // planning, in order to apply the tie-breaking rule to see who gets to use the name and who doesn't. mDNSlocal void SendQueries(mDNS *const m) { mDNSu32 slot; CacheGroup *cg; CacheRecord *cr; AuthRecord *ar; int pktcount = 0; DNSQuestion *q; // For explanation of maxExistingQuestionInterval logic, see comments for maxExistingAnnounceInterval mDNSs32 maxExistingQuestionInterval = 0; const NetworkInterfaceInfo *intf = GetFirstActiveInterface(m->HostInterfaces); CacheRecord *KnownAnswerList = mDNSNULL; // 1. If time for a query, work out what we need to do // We're expecting to send a query anyway, so see if any expiring cache records are close enough // to their NextRequiredQuery to be worth batching them together with this one FORALL_CACHERECORDS(slot, cg, cr) { if (cr->CRActiveQuestion && cr->UnansweredQueries < MaxUnansweredQueries) { if (m->timenow + TicksTTL(cr)/50 - cr->NextRequiredQuery >= 0) { debugf("Sending %d%% cache expiration query for %s", 80 + 5 * cr->UnansweredQueries, CRDisplayString(m, cr)); q = cr->CRActiveQuestion; ExpireDupSuppressInfoOnInterface(q->DupSuppress, m->timenow - TicksTTL(cr)/20, cr->resrec.InterfaceID); // For uDNS queries (TargetQID non-zero) we adjust LastQTime, // and bump UnansweredQueries so that we don't spin trying to send the same cache expiration query repeatedly if (q->Target.type) { q->SendQNow = mDNSInterfaceMark; // If targeted query, mark it } else if (!mDNSOpaque16IsZero(q->TargetQID)) { q->LastQTime = m->timenow - q->ThisQInterval; cr->UnansweredQueries++; m->mDNSStats.CacheRefreshQueries++; } else if (q->SendQNow == mDNSNULL) { q->SendQNow = cr->resrec.InterfaceID; } else if (q->SendQNow != cr->resrec.InterfaceID) { q->SendQNow = mDNSInterfaceMark; } // Indicate that this question was marked for sending // to update an existing cached answer record. // The browse throttling logic below uses this to determine // if the query should be sent. if (mDNSOpaque16IsZero(q->TargetQID)) q->CachedAnswerNeedsUpdate = mDNStrue; } } } // Scan our list of questions to see which: // *WideArea* queries need to be sent // *unicast* queries need to be sent // *multicast* queries we're definitely going to send if (m->CurrentQuestion) LogMsg("SendQueries ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = m->Questions; while (m->CurrentQuestion && m->CurrentQuestion != m->NewQuestions) { q = m->CurrentQuestion; if (q->Target.type && (q->SendQNow || TimeToSendThisQuestion(q, m->timenow))) { mDNSu8 *qptr = m->omsg.data; const mDNSu8 *const limit = m->omsg.data + sizeof(m->omsg.data); // If we fail to get a new on-demand socket (should only happen cases of the most extreme resource exhaustion), we'll try again next time if (!q->LocalSocket) q->LocalSocket = mDNSPlatformUDPSocket(zeroIPPort); if (q->LocalSocket) { InitializeDNSMessage(&m->omsg.h, q->TargetQID, QueryFlags); qptr = putQuestion(&m->omsg, qptr, limit, &q->qname, q->qtype, q->qclass); mDNSSendDNSMessage(m, &m->omsg, qptr, mDNSInterface_Any, q->LocalSocket, &q->Target, q->TargetPort, mDNSNULL, mDNSNULL, q->UseBackgroundTrafficClass); q->ThisQInterval *= QuestionIntervalStep; } if (q->ThisQInterval > MaxQuestionInterval) q->ThisQInterval = MaxQuestionInterval; q->LastQTime = m->timenow; q->LastQTxTime = m->timenow; q->RecentAnswerPkts = 0; q->SendQNow = mDNSNULL; q->ExpectUnicastResp = NonZeroTime(m->timenow); } else if (mDNSOpaque16IsZero(q->TargetQID) && !q->Target.type && TimeToSendThisQuestion(q, m->timenow)) { //LogInfo("Time to send %##s (%s) %d", q->qname.c, DNSTypeName(q->qtype), m->timenow - NextQSendTime(q)); q->SendQNow = mDNSInterfaceMark; // Mark this question for sending on all interfaces if (maxExistingQuestionInterval < q->ThisQInterval) maxExistingQuestionInterval = q->ThisQInterval; } // If m->CurrentQuestion wasn't modified out from under us, advance it now // We can't do this at the start of the loop because uDNS_CheckCurrentQuestion() depends on having // m->CurrentQuestion point to the right question if (q == m->CurrentQuestion) m->CurrentQuestion = m->CurrentQuestion->next; } while (m->CurrentQuestion) { LogInfo("SendQueries question loop 1: Skipping NewQuestion %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = m->CurrentQuestion->next; } m->CurrentQuestion = mDNSNULL; // Scan our list of questions // (a) to see if there are any more that are worth accelerating, and // (b) to update the state variables for *all* the questions we're going to send // Note: Don't set NextScheduledQuery until here, because uDNS_CheckCurrentQuestion in the loop above can add new questions to the list, // which causes NextScheduledQuery to get (incorrectly) set to m->timenow. Setting it here is the right place, because the very // next thing we do is scan the list and call SetNextQueryTime() for every question we find, so we know we end up with the right value. m->NextScheduledQuery = m->timenow + FutureTime; for (q = m->Questions; q && q != m->NewQuestions; q=q->next) { if (mDNSOpaque16IsZero(q->TargetQID) && (q->SendQNow || (!q->Target.type && ActiveQuestion(q) && q->ThisQInterval <= maxExistingQuestionInterval && AccelerateThisQuery(m,q)))) { // If at least halfway to next query time, advance to next interval // If less than halfway to next query time, then // treat this as logically a repeat of the last transmission, without advancing the interval if (m->timenow - (q->LastQTime + (q->ThisQInterval/2)) >= 0) { // If we have reached the answer threshold for this question, // don't send it again until MaxQuestionInterval unless: // one of its cached answers needs to be refreshed, // or it's the initial query for a kDNSServiceFlagsThresholdFinder mode browse. if (q->BrowseThreshold && (q->CurrentAnswers >= q->BrowseThreshold) && (q->CachedAnswerNeedsUpdate == mDNSfalse) && !((q->flags & kDNSServiceFlagsThresholdFinder) && (q->ThisQInterval == InitialQuestionInterval))) { q->SendQNow = mDNSNULL; q->ThisQInterval = MaxQuestionInterval; q->LastQTime = m->timenow; q->RequestUnicast = 0; LogInfo("SendQueries: (%s) %##s reached threshold of %d answers", DNSTypeName(q->qtype), q->qname.c, q->BrowseThreshold); } else { // Mark this question for sending on all interfaces q->SendQNow = mDNSInterfaceMark; q->ThisQInterval *= QuestionIntervalStep; } debugf("SendQueries: %##s (%s) next interval %d seconds RequestUnicast = %d", q->qname.c, DNSTypeName(q->qtype), q->ThisQInterval / InitialQuestionInterval, q->RequestUnicast); if (q->ThisQInterval > MaxQuestionInterval) { q->ThisQInterval = MaxQuestionInterval; } else if (q->CurrentAnswers == 0 && q->ThisQInterval == InitialQuestionInterval * QuestionIntervalStep3 && !q->RequestUnicast && !(RRTypeIsAddressType(q->qtype) && CacheHasAddressTypeForName(m, &q->qname, q->qnamehash))) { // Generally don't need to log this. // It's not especially noteworthy if a query finds no results -- this usually happens for domain // enumeration queries in the LL subdomain (e.g. "db._dns-sd._udp.0.0.254.169.in-addr.arpa") // and when there simply happen to be no instances of the service the client is looking // for (e.g. iTunes is set to look for RAOP devices, and the current network has none). debugf("SendQueries: Zero current answers for %##s (%s); will reconfirm antecedents", q->qname.c, DNSTypeName(q->qtype)); // Sending third query, and no answers yet; time to begin doubting the source ReconfirmAntecedents(m, &q->qname, q->qnamehash, 0); } } // Mark for sending. (If no active interfaces, then don't even try.) q->SendOnAll = (q->SendQNow == mDNSInterfaceMark); if (q->SendOnAll) { q->SendQNow = !intf ? mDNSNULL : (q->InterfaceID) ? q->InterfaceID : intf->InterfaceID; q->LastQTime = m->timenow; } // If we recorded a duplicate suppression for this question less than half an interval ago, // then we consider it recent enough that we don't need to do an identical query ourselves. ExpireDupSuppressInfo(q->DupSuppress, m->timenow - q->ThisQInterval/2); q->LastQTxTime = m->timenow; q->RecentAnswerPkts = 0; if (q->RequestUnicast) q->RequestUnicast--; } // For all questions (not just the ones we're sending) check what the next scheduled event will be // We don't need to consider NewQuestions here because for those we'll set m->NextScheduledQuery in AnswerNewQuestion SetNextQueryTime(m,q); } // 2. Scan our authoritative RR list to see what probes we might need to send m->NextScheduledProbe = m->timenow + FutureTime; if (m->CurrentRecord) LogMsg("SendQueries ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); m->CurrentRecord = m->ResourceRecords; while (m->CurrentRecord) { ar = m->CurrentRecord; m->CurrentRecord = ar->next; if (!AuthRecord_uDNS(ar) && ar->resrec.RecordType == kDNSRecordTypeUnique) // For all records that are still probing... { // 1. If it's not reached its probe time, just make sure we update m->NextScheduledProbe correctly if (m->timenow - (ar->LastAPTime + ar->ThisAPInterval) < 0) { SetNextAnnounceProbeTime(m, ar); } // 2. else, if it has reached its probe time, mark it for sending and then update m->NextScheduledProbe correctly else if (ar->ProbeCount) { if (ar->AddressProxy.type == mDNSAddrType_IPv4) { // There's a problem here. If a host is waking up, and we probe to see if it responds, then // it will see those ARP probes as signalling intent to use the address, so it picks a different one. // A more benign way to find out if a host is responding to ARPs might be send a standard ARP *request* // (using our sender IP address) instead of an ARP *probe* (using all-zero sender IP address). // A similar concern may apply to the NDP Probe too. -- SC LogSPS("SendQueries ARP Probe %d %s %s", ar->ProbeCount, InterfaceNameForID(m, ar->resrec.InterfaceID), ARDisplayString(m,ar)); SendARP(m, 1, ar, &zerov4Addr, &zeroEthAddr, &ar->AddressProxy.ip.v4, &ar->WakeUp.IMAC); } else if (ar->AddressProxy.type == mDNSAddrType_IPv6) { LogSPS("SendQueries NDP Probe %d %s %s", ar->ProbeCount, InterfaceNameForID(m, ar->resrec.InterfaceID), ARDisplayString(m,ar)); // IPv6 source = zero // No target hardware address // IPv6 target address is address we're probing // Ethernet destination address is Ethernet interface address of the Sleep Proxy client we're probing SendNDP(m, NDP_Sol, 0, ar, &zerov6Addr, mDNSNULL, &ar->AddressProxy.ip.v6, &ar->WakeUp.IMAC); } // Mark for sending. (If no active interfaces, then don't even try.) ar->SendRNow = (!intf || ar->WakeUp.HMAC.l[0]) ? mDNSNULL : ar->resrec.InterfaceID ? ar->resrec.InterfaceID : intf->InterfaceID; ar->LastAPTime = m->timenow; // When we have a late conflict that resets a record to probing state we use a special marker value greater // than DefaultProbeCountForTypeUnique. Here we detect that state and reset ar->ProbeCount back to the right value. if (ar->ProbeCount > DefaultProbeCountForTypeUnique) ar->ProbeCount = DefaultProbeCountForTypeUnique; ar->ProbeCount--; SetNextAnnounceProbeTime(m, ar); if (ar->ProbeCount == 0) { // If this is the last probe for this record, then see if we have any matching records // on our duplicate list which should similarly have their ProbeCount cleared to zero... AuthRecord *r2; for (r2 = m->DuplicateRecords; r2; r2=r2->next) if (r2->resrec.RecordType == kDNSRecordTypeUnique && RecordIsLocalDuplicate(r2, ar)) r2->ProbeCount = 0; // ... then acknowledge this record to the client. // We do this optimistically, just as we're about to send the third probe. // This helps clients that both advertise and browse, and want to filter themselves // from the browse results list, because it helps ensure that the registration // confirmation will be delivered 1/4 second *before* the browse "add" event. // A potential downside is that we could deliver a registration confirmation and then find out // moments later that there's a name conflict, but applications have to be prepared to handle // late conflicts anyway (e.g. on connection of network cable, etc.), so this is nothing new. if (!ar->Acknowledged) AcknowledgeRecord(m, ar); } } // else, if it has now finished probing, move it to state Verified, // and update m->NextScheduledResponse so it will be announced else { if (!ar->Acknowledged) AcknowledgeRecord(m, ar); // Defensive, just in case it got missed somehow ar->resrec.RecordType = kDNSRecordTypeVerified; ar->ThisAPInterval = DefaultAnnounceIntervalForTypeUnique; ar->LastAPTime = m->timenow - DefaultAnnounceIntervalForTypeUnique; SetNextAnnounceProbeTime(m, ar); } } } m->CurrentRecord = m->DuplicateRecords; while (m->CurrentRecord) { ar = m->CurrentRecord; m->CurrentRecord = ar->next; if (ar->resrec.RecordType == kDNSRecordTypeUnique && ar->ProbeCount == 0 && !ar->Acknowledged) AcknowledgeRecord(m, ar); } // 3. Now we know which queries and probes we're sending, // go through our interface list sending the appropriate queries on each interface while (intf) { int OwnerRecordSpace = (m->AnnounceOwner && intf->MAC.l[0]) ? DNSOpt_Header_Space + DNSOpt_Owner_Space(&m->PrimaryMAC, &intf->MAC) : 0; int TraceRecordSpace = (mDNS_McastTracingEnabled && MDNS_TRACER) ? DNSOpt_Header_Space + DNSOpt_TraceData_Space : 0; mDNSu8 *queryptr = m->omsg.data; mDNSBool useBackgroundTrafficClass = mDNSfalse; // set if we should use background traffic class InitializeDNSMessage(&m->omsg.h, zeroID, QueryFlags); if (KnownAnswerList) verbosedebugf("SendQueries: KnownAnswerList set... Will continue from previous packet"); if (!KnownAnswerList) { // Start a new known-answer list CacheRecord **kalistptr = &KnownAnswerList; mDNSu32 answerforecast = OwnerRecordSpace + TraceRecordSpace; // Start by assuming we'll need at least enough space to put the Owner+Tracer Option // Put query questions in this packet for (q = m->Questions; q && q != m->NewQuestions; q=q->next) { if (mDNSOpaque16IsZero(q->TargetQID) && (q->SendQNow == intf->InterfaceID)) { mDNSBool Suppress = mDNSfalse; debugf("SendQueries: %s question for %##s (%s) at %d forecast total %d", SuppressOnThisInterface(q->DupSuppress, intf) ? "Suppressing" : "Putting ", q->qname.c, DNSTypeName(q->qtype), queryptr - m->omsg.data, queryptr + answerforecast - m->omsg.data); // If interface is P2P type, verify that query should be sent over it. if (!mDNSPlatformValidQuestionForInterface(q, intf)) { q->SendQNow = (q->InterfaceID || !q->SendOnAll) ? mDNSNULL : GetNextActiveInterfaceID(intf); } // If we're suppressing this question, or we successfully put it, update its SendQNow state else if ((Suppress = SuppressOnThisInterface(q->DupSuppress, intf)) || BuildQuestion(m, intf, &m->omsg, &queryptr, q, &kalistptr, &answerforecast)) { // We successfully added the question to the packet. Make sure that // we also send the NSEC3 record if required. BuildQuestion accounted for // the space. // // Note: We don't suppress anonymous questions and hence Suppress should always // be zero. if (Suppress) m->mDNSStats.DupQuerySuppressions++; if (!Suppress && q->AnonInfo) { debugf("SendQueries: marking for question %##s, Suppress %d", q->qname.c, Suppress); q->AnonInfo->SendNow = intf->InterfaceID; } q->SendQNow = (q->InterfaceID || !q->SendOnAll) ? mDNSNULL : GetNextActiveInterfaceID(intf); if (q->WakeOnResolveCount) { mDNSSendWakeOnResolve(m, q); q->WakeOnResolveCount--; } // use background traffic class if any included question requires it if (q->UseBackgroundTrafficClass) { useBackgroundTrafficClass = mDNStrue; } } } } // Put probe questions in this packet for (ar = m->ResourceRecords; ar; ar=ar->next) { if (ar->SendRNow != intf->InterfaceID) continue; // If interface is a P2P variant, verify that the probe should be sent over it. if (!mDNSPlatformValidRecordForInterface(ar, intf->InterfaceID)) { ar->SendRNow = (ar->resrec.InterfaceID) ? mDNSNULL : GetNextActiveInterfaceID(intf); ar->IncludeInProbe = mDNSfalse; } else { mDNSBool ucast = (ar->ProbeCount >= DefaultProbeCountForTypeUnique-1) && m->CanReceiveUnicastOn5353 && intf->SupportsUnicastMDNSResponse; mDNSu16 ucbit = (mDNSu16)(ucast ? kDNSQClass_UnicastResponse : 0); const mDNSu8 *const limit = m->omsg.data + (m->omsg.h.numQuestions ? NormalMaxDNSMessageData : AbsoluteMaxDNSMessageData); // We forecast: compressed name (2) type (2) class (2) TTL (4) rdlength (2) rdata (n) mDNSu32 forecast = answerforecast + 12 + ar->resrec.rdestimate; mDNSBool putProbe = mDNStrue; mDNSu16 qclass = ar->resrec.rrclass | ucbit; {// Determine if this probe question is already in packet's dns message const mDNSu8 *questionptr = m->omsg.data; DNSQuestion question; mDNSu16 n; for (n = 0; n < m->omsg.h.numQuestions && questionptr; n++) { questionptr = getQuestion(&m->omsg, questionptr, limit, mDNSInterface_Any, &question); if (questionptr && (question.qtype == kDNSQType_ANY) && (question.qclass == qclass) && (question.qnamehash == ar->resrec.namehash) && SameDomainName(&question.qname, ar->resrec.name)) { putProbe = mDNSfalse; // set to false if already in message break; } } } if (putProbe) { mDNSu8 *newptr = putQuestion(&m->omsg, queryptr, limit - forecast, ar->resrec.name, kDNSQType_ANY, qclass); if (newptr) { queryptr = newptr; answerforecast = forecast; ar->SendRNow = (ar->resrec.InterfaceID) ? mDNSNULL : GetNextActiveInterfaceID(intf); ar->IncludeInProbe = mDNStrue; verbosedebugf("SendQueries: Put Question %##s (%s) probecount %d InterfaceID= %d %d %d", ar->resrec.name->c, DNSTypeName(ar->resrec.rrtype), ar->ProbeCount, ar->resrec.InterfaceID, ar->resrec.rdestimate, answerforecast); } } else { ar->SendRNow = (ar->resrec.InterfaceID) ? mDNSNULL : GetNextActiveInterfaceID(intf); ar->IncludeInProbe = mDNStrue; } } } } // Put our known answer list (either new one from this question or questions, or remainder of old one from last time) while (KnownAnswerList) { CacheRecord *ka = KnownAnswerList; mDNSu32 SecsSinceRcvd = ((mDNSu32)(m->timenow - ka->TimeRcvd)) / mDNSPlatformOneSecond; mDNSu8 *newptr = PutResourceRecordTTLWithLimit(&m->omsg, queryptr, &m->omsg.h.numAnswers, &ka->resrec, ka->resrec.rroriginalttl - SecsSinceRcvd, m->omsg.data + NormalMaxDNSMessageData - OwnerRecordSpace - TraceRecordSpace); if (newptr) { verbosedebugf("SendQueries: Put %##s (%s) at %d - %d", ka->resrec.name->c, DNSTypeName(ka->resrec.rrtype), queryptr - m->omsg.data, newptr - m->omsg.data); queryptr = newptr; KnownAnswerList = ka->NextInKAList; ka->NextInKAList = mDNSNULL; } else { // If we ran out of space and we have more than one question in the packet, that's an error -- // we shouldn't have put more than one question if there was a risk of us running out of space. if (m->omsg.h.numQuestions > 1) LogMsg("SendQueries: Put %d answers; No more space for known answers", m->omsg.h.numAnswers); m->omsg.h.flags.b[0] |= kDNSFlag0_TC; break; } } for (ar = m->ResourceRecords; ar; ar=ar->next) { if (ar->IncludeInProbe) { mDNSu8 *newptr = PutResourceRecord(&m->omsg, queryptr, &m->omsg.h.numAuthorities, &ar->resrec); ar->IncludeInProbe = mDNSfalse; if (newptr) queryptr = newptr; else LogMsg("SendQueries: How did we fail to have space for the Update record %s", ARDisplayString(m,ar)); } } for (q = m->Questions; q; q = q->next) { if (q->AnonInfo && q->AnonInfo->SendNow == intf->InterfaceID) { mDNSu8 *newptr = PutResourceRecord(&m->omsg, queryptr, &m->omsg.h.numAuthorities, q->AnonInfo->nsec3RR); if (newptr) { debugf("SendQueries: Added NSEC3 record %s on InterfaceID %p", RRDisplayString(m, q->AnonInfo->nsec3RR), intf->InterfaceID); queryptr = newptr; } else { LogMsg("SendQueries: ERROR!! Cannot add NSEC3 record %s on InterfaceID %p", RRDisplayString(m, q->AnonInfo->nsec3RR), intf->InterfaceID); } q->AnonInfo->SendNow = mDNSNULL; } } if (queryptr > m->omsg.data) { // If we have data to send, add OWNER/TRACER/OWNER+TRACER option if necessary, then send packet if (OwnerRecordSpace || TraceRecordSpace) { AuthRecord opt; mDNS_SetupResourceRecord(&opt, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); opt.resrec.rrclass = NormalMaxDNSMessageData; opt.resrec.rdlength = sizeof(rdataOPT); opt.resrec.rdestimate = sizeof(rdataOPT); if (OwnerRecordSpace && TraceRecordSpace) { opt.resrec.rdlength += sizeof(rdataOPT); // Two options in this OPT record opt.resrec.rdestimate += sizeof(rdataOPT); SetupOwnerOpt(m, intf, &opt.resrec.rdata->u.opt[0]); SetupTracerOpt(m, &opt.resrec.rdata->u.opt[1]); } else if (OwnerRecordSpace) { SetupOwnerOpt(m, intf, &opt.resrec.rdata->u.opt[0]); } else if (TraceRecordSpace) { SetupTracerOpt(m, &opt.resrec.rdata->u.opt[0]); } queryptr = PutResourceRecordTTLWithLimit(&m->omsg, queryptr, &m->omsg.h.numAdditionals, &opt.resrec, opt.resrec.rroriginalttl, m->omsg.data + AbsoluteMaxDNSMessageData); if (!queryptr) { LogMsg("SendQueries: How did we fail to have space for %s %s OPT record (%d/%d/%d/%d) %s", OwnerRecordSpace ? "OWNER" : "", TraceRecordSpace ? "TRACER" : "", m->omsg.h.numQuestions, m->omsg.h.numAnswers, m->omsg.h.numAuthorities, m->omsg.h.numAdditionals, ARDisplayString(m, &opt)); } if (queryptr > m->omsg.data + NormalMaxDNSMessageData) { if (m->omsg.h.numQuestions != 1 || m->omsg.h.numAnswers != 0 || m->omsg.h.numAuthorities != 1 || m->omsg.h.numAdditionals != 1) LogMsg("SendQueries: Why did we generate oversized packet with %s %s OPT record %p %p %p (%d/%d/%d/%d) %s", OwnerRecordSpace ? "OWNER" : "", TraceRecordSpace ? "TRACER" : "", m->omsg.data, m->omsg.data + NormalMaxDNSMessageData, queryptr, m->omsg.h.numQuestions, m->omsg.h.numAnswers, m->omsg.h.numAuthorities, m->omsg.h.numAdditionals, ARDisplayString(m, &opt)); } } if ((m->omsg.h.flags.b[0] & kDNSFlag0_TC) && m->omsg.h.numQuestions > 1) LogMsg("SendQueries: Should not have more than one question (%d) in a truncated packet", m->omsg.h.numQuestions); debugf("SendQueries: Sending %d Question%s %d Answer%s %d Update%s on %p", m->omsg.h.numQuestions, m->omsg.h.numQuestions == 1 ? "" : "s", m->omsg.h.numAnswers, m->omsg.h.numAnswers == 1 ? "" : "s", m->omsg.h.numAuthorities, m->omsg.h.numAuthorities == 1 ? "" : "s", intf->InterfaceID); if (intf->IPv4Available) mDNSSendDNSMessage(m, &m->omsg, queryptr, intf->InterfaceID, mDNSNULL, &AllDNSLinkGroup_v4, MulticastDNSPort, mDNSNULL, mDNSNULL, useBackgroundTrafficClass); if (intf->IPv6Available) mDNSSendDNSMessage(m, &m->omsg, queryptr, intf->InterfaceID, mDNSNULL, &AllDNSLinkGroup_v6, MulticastDNSPort, mDNSNULL, mDNSNULL, useBackgroundTrafficClass); if (!m->SuppressSending) m->SuppressSending = NonZeroTime(m->timenow + (mDNSPlatformOneSecond+9)/10); if (++pktcount >= 1000) { LogMsg("SendQueries exceeded loop limit %d: giving up", pktcount); break; } // There might be more records left in the known answer list, or more questions to send // on this interface, so go around one more time and try again. } else // Nothing more to send on this interface; go to next { const NetworkInterfaceInfo *next = GetFirstActiveInterface(intf->next); #if MDNS_DEBUGMSGS && 0 const char *const msg = next ? "SendQueries: Nothing more on %p; moving to %p" : "SendQueries: Nothing more on %p"; debugf(msg, intf, next); #endif intf = next; } } // 4. Final housekeeping // 4a. Debugging check: Make sure we announced all our records for (ar = m->ResourceRecords; ar; ar=ar->next) if (ar->SendRNow) { if (ar->ARType != AuthRecordLocalOnly && ar->ARType != AuthRecordP2P) LogInfo("SendQueries: No active interface %d to send probe: %d %s", IID(ar->SendRNow), IID(ar->resrec.InterfaceID), ARDisplayString(m, ar)); ar->SendRNow = mDNSNULL; } // 4b. When we have lingering cache records that we're keeping around for a few seconds in the hope // that their interface which went away might come back again, the logic will want to send queries // for those records, but we can't because their interface isn't here any more, so to keep the // state machine ticking over we just pretend we did so. // If the interface does not come back in time, the cache record will expire naturally FORALL_CACHERECORDS(slot, cg, cr) { if (cr->CRActiveQuestion && cr->UnansweredQueries < MaxUnansweredQueries) { if (m->timenow + TicksTTL(cr)/50 - cr->NextRequiredQuery >= 0) { cr->UnansweredQueries++; cr->CRActiveQuestion->SendQNow = mDNSNULL; SetNextCacheCheckTimeForRecord(m, cr); } } } // 4c. Debugging check: Make sure we sent all our planned questions // Do this AFTER the lingering cache records check above, because that will prevent spurious warnings for questions // we legitimately couldn't send because the interface is no longer available for (q = m->Questions; q; q=q->next) { if (q->SendQNow) { DNSQuestion *x; for (x = m->NewQuestions; x; x=x->next) if (x == q) break; // Check if this question is a NewQuestion // There will not be an active interface for questions applied to mDNSInterface_BLE // so don't log the warning in that case. if (q->InterfaceID != mDNSInterface_BLE) LogInfo("SendQueries: No active interface %d to send %s question: %d %##s (%s)", IID(q->SendQNow), x ? "new" : "old", IID(q->InterfaceID), q->qname.c, DNSTypeName(q->qtype)); q->SendQNow = mDNSNULL; } q->CachedAnswerNeedsUpdate = mDNSfalse; } } mDNSlocal void SendWakeup(mDNS *const m, mDNSInterfaceID InterfaceID, mDNSEthAddr *EthAddr, mDNSOpaque48 *password, mDNSBool unicastOnly) { int i, j; mDNSu8 *ptr = m->omsg.data; NetworkInterfaceInfo *intf = FirstInterfaceForID(m, InterfaceID); if (!intf) { LogMsg("SendARP: No interface with InterfaceID %p found", InterfaceID); return; } // 0x00 Destination address for (i=0; i<6; i++) *ptr++ = EthAddr->b[i]; // 0x06 Source address (Note: Since we don't currently set the BIOCSHDRCMPLT option, BPF will fill in the real interface address for us) for (i=0; i<6; i++) *ptr++ = intf->MAC.b[0]; // 0x0C Ethertype (0x0842) *ptr++ = 0x08; *ptr++ = 0x42; // 0x0E Wakeup sync sequence for (i=0; i<6; i++) *ptr++ = 0xFF; // 0x14 Wakeup data for (j=0; j<16; j++) for (i=0; i<6; i++) *ptr++ = EthAddr->b[i]; // 0x74 Password for (i=0; i<6; i++) *ptr++ = password->b[i]; mDNSPlatformSendRawPacket(m->omsg.data, ptr, InterfaceID); if (!unicastOnly) { // For Ethernet switches that don't flood-foward packets with unknown unicast destination MAC addresses, // broadcast is the only reliable way to get a wakeup packet to the intended target machine. // For 802.11 WPA networks, where a sleeping target machine may have missed a broadcast/multicast // key rotation, unicast is the only way to get a wakeup packet to the intended target machine. // So, we send one of each, unicast first, then broadcast second. for (i=0; i<6; i++) m->omsg.data[i] = 0xFF; mDNSPlatformSendRawPacket(m->omsg.data, ptr, InterfaceID); } } // *************************************************************************** #if COMPILER_LIKES_PRAGMA_MARK #pragma mark - #pragma mark - RR List Management & Task Management #endif // Whenever a question is answered, reset its state so that we don't query // the network repeatedly. This happens first time when we answer the question and // and later when we refresh the cache. mDNSlocal void ResetQuestionState(mDNS *const m, DNSQuestion *q) { q->LastQTime = m->timenow; q->LastQTxTime = m->timenow; q->RecentAnswerPkts = 0; q->ThisQInterval = MaxQuestionInterval; q->RequestUnicast = 0; // Reset unansweredQueries so that we don't penalize this server later when we // start sending queries when the cache expires. q->unansweredQueries = 0; debugf("ResetQuestionState: Set MaxQuestionInterval for %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); } // Note: AnswerCurrentQuestionWithResourceRecord can call a user callback, which may change the record list and/or question list. // Any code walking either list must use the m->CurrentQuestion (and possibly m->CurrentRecord) mechanism to protect against this. // In fact, to enforce this, the routine will *only* answer the question currently pointed to by m->CurrentQuestion, // which will be auto-advanced (possibly to NULL) if the client callback cancels the question. mDNSexport void AnswerCurrentQuestionWithResourceRecord(mDNS *const m, CacheRecord *const rr, const QC_result AddRecord) { DNSQuestion *const q = m->CurrentQuestion; const mDNSBool followcname = FollowCNAME(q, &rr->resrec, AddRecord); verbosedebugf("AnswerCurrentQuestionWithResourceRecord:%4lu %s TTL %d %s", q->CurrentAnswers, AddRecord ? "Add" : "Rmv", rr->resrec.rroriginalttl, CRDisplayString(m, rr)); // When the response for the question was validated, the entire rrset was validated. If we deliver // a RMV for a single record in the rrset, we invalidate the response. If we deliver another add // in the future, we will do the revalidation again. // // Also, if we deliver an ADD for a negative cache record and it has no NSEC/NSEC3, the ValidationStatus needs // to be reset. This happens normally when we deliver a "secure" negative response followed by an insecure // negative response which can happen e.g., when disconnecting from network that leads to a negative response // due to no DNS servers. As we don't deliver RMVs for negative responses that were delivered before, we need // to do it on the next ADD of a negative cache record. This ADD could be the result of a timeout, no DNS servers // etc. in which case we need to reset the state to make sure we don't deliver them as secure. If this is // a real negative response, we would reset the state here and validate the results at the end of this function. // or the real response again if we purge the cache. if (q->ValidationRequired && ((AddRecord == QC_rmv) || (rr->resrec.RecordType == kDNSRecordTypePacketNegative && (AddRecord == QC_add)))) { q->ValidationStatus = 0; q->ValidationState = DNSSECValRequired; } // Normally we don't send out the unicast query if we have answered using our local only auth records e.g., /etc/hosts. // But if the query for "A" record has a local answer but query for "AAAA" record has no local answer, we might // send the AAAA query out which will come back with CNAME and will also answer the "A" query. To prevent that, // we check to see if that query already has a unique local answer. if (q->LOAddressAnswers) { LogInfo("AnswerCurrentQuestionWithResourceRecord: Question %p %##s (%s) not answering with record %s due to " "LOAddressAnswers %d", q, q->qname.c, DNSTypeName(q->qtype), ARDisplayString(m, rr), q->LOAddressAnswers); return; } if (QuerySuppressed(q)) { // If the query is suppressed, then we don't want to answer from the cache. But if this query is // supposed to time out, we still want to callback the clients. We do this only for TimeoutQuestions // that are timing out, which we know are answered with negative cache record when timing out. if (!q->TimeoutQuestion || rr->resrec.RecordType != kDNSRecordTypePacketNegative || (m->timenow - q->StopTime < 0)) return; } #if AWD_METRICS if ((AddRecord == QC_add) && Question_uDNS(q) && !followcname) { const domainname * queryName; mDNSu32 responseLatencyMs; mDNSBool isForCellular; queryName = q->metrics.originalQName ? q->metrics.originalQName : &q->qname; isForCellular = (q->qDNSServer && q->qDNSServer->cellIntf); if (!q->metrics.answered) { if (q->metrics.querySendCount > 0) { responseLatencyMs = ((m->timenow - q->metrics.firstQueryTime) * 1000) / mDNSPlatformOneSecond; } else { responseLatencyMs = 0; } MetricsUpdateDNSQueryStats(queryName, q->qtype, &rr->resrec, q->metrics.querySendCount, responseLatencyMs, isForCellular); q->metrics.answered = mDNStrue; } if (q->metrics.querySendCount > 0) { MetricsUpdateDNSResolveStats(queryName, &rr->resrec, isForCellular); } } #endif // Note: Use caution here. In the case of records with rr->DelayDelivery set, AnswerCurrentQuestionWithResourceRecord(... mDNStrue) // may be called twice, once when the record is received, and again when it's time to notify local clients. // If any counters or similar are added here, care must be taken to ensure that they are not double-incremented by this. rr->LastUsed = m->timenow; if (AddRecord == QC_add && !q->DuplicateOf && rr->CRActiveQuestion != q) { if (!rr->CRActiveQuestion) m->rrcache_active++; // If not previously active, increment rrcache_active count debugf("AnswerCurrentQuestionWithResourceRecord: Updating CRActiveQuestion from %p to %p for cache record %s, CurrentAnswer %d", rr->CRActiveQuestion, q, CRDisplayString(m,rr), q->CurrentAnswers); rr->CRActiveQuestion = q; // We know q is non-null SetNextCacheCheckTimeForRecord(m, rr); } // If this is: // (a) a no-cache add, where we've already done at least one 'QM' query, or // (b) a normal add, where we have at least one unique-type answer, // then there's no need to keep polling the network. // (If we have an answer in the cache, then we'll automatically ask again in time to stop it expiring.) // We do this for mDNS questions and uDNS one-shot questions, but not for // uDNS LongLived questions, because that would mess up our LLQ lease renewal timing. if ((AddRecord == QC_addnocache && !q->RequestUnicast) || (AddRecord == QC_add && (q->ExpectUnique || (rr->resrec.RecordType & kDNSRecordTypePacketUniqueMask)))) if (ActiveQuestion(q) && (mDNSOpaque16IsZero(q->TargetQID) || !q->LongLived)) { ResetQuestionState(m, q); } if (rr->DelayDelivery) return; // We'll come back later when CacheRecordDeferredAdd() calls us #if USE_DNS64 // If DNS64StateMachine() returns true, then the question was restarted as a different question, so return. if (!mDNSOpaque16IsZero(q->TargetQID) && DNS64StateMachine(m, q, &rr->resrec, AddRecord)) return; #endif #ifdef USE_LIBIDN if (rr->resrec.RecordType == kDNSRecordTypePacketNegative) // If negative answer, check if we need to try Punycode conversion { domainname newname; if (PerformNextPunycodeConversion(q, &newname)) // Itertative Punycode conversion succeeded, so reissue question with new name { UDPSocket *const sock = q->LocalSocket; // Save old socket and transaction ID const mDNSOpaque16 id = q->TargetQID; q->LocalSocket = mDNSNULL; mDNS_StopQuery_internal(m, q); // Stop old query AssignDomainName(&q->qname, &newname); // Update qname q->qnamehash = DomainNameHashValue(&q->qname); // and namehash mDNS_StartQuery_internal(m, q); // Start new query if (sock) // Transplant saved socket, if appropriate { if (q->DuplicateOf) mDNSPlatformUDPClose(sock); else { q->LocalSocket = sock; q->TargetQID = id; } } return; // All done for now; wait until we get the next answer } } #endif // USE_LIBIDN // Only deliver negative answers if client has explicitly requested them except when we are forcing a negative response // for the purpose of retrying search domains/timeout OR the question is suppressed if (rr->resrec.RecordType == kDNSRecordTypePacketNegative || (q->qtype != kDNSType_NSEC && RRAssertsNonexistence(&rr->resrec, q->qtype))) if (!AddRecord || (AddRecord != QC_suppressed && AddRecord != QC_forceresponse && !q->ReturnIntermed)) return; // For CNAME results to non-CNAME questions, only inform the client if they explicitly requested that if (q->QuestionCallback && !q->NoAnswer && (!followcname || q->ReturnIntermed)) { mDNS_DropLockBeforeCallback(); // Allow client (and us) to legally make mDNS API calls if (q->qtype != kDNSType_NSEC && RRAssertsNonexistence(&rr->resrec, q->qtype)) { CacheRecord neg; MakeNegativeCacheRecord(m, &neg, &q->qname, q->qnamehash, q->qtype, q->qclass, 1, rr->resrec.InterfaceID, q->qDNSServer); q->QuestionCallback(m, q, &neg.resrec, AddRecord); } else { #if USE_DNS64 if (DNS64ShouldAnswerQuestion(q, &rr->resrec)) { DNS64AnswerQuestion(m, q, &rr->resrec, AddRecord); } else #endif { q->QuestionCallback(m, q, &rr->resrec, AddRecord); } } mDNS_ReclaimLockAfterCallback(); // Decrement mDNS_reentrancy to block mDNS API calls again } // If this is an "Add" operation and this question needs validation, validate the response. // In the case of negative responses, extra care should be taken. Negative cache records are // used for many purposes. For example, // // 1) Suppressing questions (SuppressUnusable) // 2) Timeout questions // 3) The name does not exist // 4) No DNS servers are available and we need a quick response for the application // // (1) and (2) are handled by "QC_add" check as AddRecord would be "QC_forceresponse" or "QC_suppressed" // in that case. For (3), it is possible that we don't get nsecs back but we still need to call // VerifySignature so that we can deliver the appropriate DNSSEC result. There is no point in verifying // signature for (4) and hence the explicit check for q->qDNSServer. // if (m->CurrentQuestion == q && (AddRecord == QC_add) && !q->ValidatingResponse && q->ValidationRequired && q->ValidationState == DNSSECValRequired && q->qDNSServer) { q->ValidationState = DNSSECValInProgress; // Treat it as callback call as that's what dnssec code expects mDNS_DropLockBeforeCallback(); // Allow client (and us) to legally make mDNS API calls VerifySignature(m, mDNSNULL, q); mDNS_ReclaimLockAfterCallback(); // Decrement mDNS_reentrancy to block mDNS API calls again return; } // Note: Proceed with caution here because client callback function is allowed to do anything, // including starting/stopping queries, registering/deregistering records, etc. // // If we get a CNAME back while we are validating the response (i.e., CNAME for DS, DNSKEY, RRSIG), // don't follow them. If it is a ValidationRequired question, wait for the CNAME to be validated // first before following it if ((m->CurrentQuestion == q) && followcname && !ValidatingQuestion(q)) AnswerQuestionByFollowingCNAME(m, q, &rr->resrec); } mDNSlocal void CacheRecordDeferredAdd(mDNS *const m, CacheRecord *rr) { rr->DelayDelivery = 0; if (m->CurrentQuestion) LogMsg("CacheRecordDeferredAdd ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = m->Questions; while (m->CurrentQuestion && m->CurrentQuestion != m->NewQuestions) { DNSQuestion *q = m->CurrentQuestion; if (ResourceRecordAnswersQuestion(&rr->resrec, q)) AnswerCurrentQuestionWithResourceRecord(m, rr, QC_add); if (m->CurrentQuestion == q) // If m->CurrentQuestion was not auto-advanced, do it ourselves now m->CurrentQuestion = q->next; } m->CurrentQuestion = mDNSNULL; } mDNSlocal mDNSs32 CheckForSoonToExpireRecords(mDNS *const m, const domainname *const name, const mDNSu32 namehash, mDNSBool *purge) { const mDNSs32 threshhold = m->timenow + mDNSPlatformOneSecond; // See if there are any records expiring within one second const mDNSs32 start = m->timenow - 0x10000000; mDNSs32 delay = start; CacheGroup *cg = CacheGroupForName(m, namehash, name); const CacheRecord *rr; if (purge) *purge = mDNSfalse; for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) { // If there are records that will expire soon, there are cases that need delayed // delivery of events: // // 1) A new cache entry is about to be added as a replacement. The caller needs to // deliver a RMV (for the current old entry) followed by ADD (for the new entry). // It needs to schedule the timer for the next cache expiry (ScheduleNextCacheCheckTime), // so that the cache entry can be purged (purging causes the RMV followed by ADD) // // 2) A new question is about to be answered and the caller needs to know whether it's // scheduling should be delayed so that the question is not answered with this record. // Instead of delivering an ADD (old entry) followed by RMV (old entry) and another ADD // (new entry), a single ADD can be delivered by delaying the scheduling of the question // immediately. // // When the unicast cache record is created, it's TTL has been extended beyond its value // given in the resource record (See RRAdjustTTL). If it is in the "extended" time, the // cache is already expired and we set "purge" to indicate that. When "purge" is set, the // return value of the function should be ignored by the callers. // // Note: For case (1), "purge" argument is NULL and hence the following checks are skipped. // It is okay to skip in that case because the cache records have been set to expire almost // immediately and the extended time does not apply. // // Also, if there is already an active question we don't try to optimize as purging the cache // would end up delivering RMV for the active question and hence we avoid that. if (purge && !rr->resrec.InterfaceID && !rr->CRActiveQuestion && rr->resrec.rroriginalttl) { mDNSu32 uTTL = RRUnadjustedTTL(rr->resrec.rroriginalttl); if (m->timenow - (rr->TimeRcvd + ((mDNSs32)uTTL * mDNSPlatformOneSecond)) >= 0) { LogInfo("CheckForSoonToExpireRecords: %s: rroriginalttl %u, unadjustedTTL %u, currentTTL %u", CRDisplayString(m, rr), rr->resrec.rroriginalttl, uTTL, (m->timenow - rr->TimeRcvd)/mDNSPlatformOneSecond); *purge = mDNStrue; continue; } } if (threshhold - RRExpireTime(rr) >= 0) // If we have records about to expire within a second { if (delay - RRExpireTime(rr) < 0) // then delay until after they've been deleted delay = RRExpireTime(rr); } } if (delay - start > 0) return(NonZeroTime(delay)); else return(0); } // CacheRecordAdd is only called from CreateNewCacheEntry, *never* directly as a result of a client API call. // If new questions are created as a result of invoking client callbacks, they will be added to // the end of the question list, and m->NewQuestions will be set to indicate the first new question. // rr is a new CacheRecord just received into our cache // (kDNSRecordTypePacketAns/PacketAnsUnique/PacketAdd/PacketAddUnique). // Note: CacheRecordAdd calls AnswerCurrentQuestionWithResourceRecord which can call a user callback, // which may change the record list and/or question list. // Any code walking either list must use the CurrentQuestion and/or CurrentRecord mechanism to protect against this. mDNSlocal void CacheRecordAdd(mDNS *const m, CacheRecord *rr) { DNSQuestion *q; // We stop when we get to NewQuestions -- if we increment their CurrentAnswers/LargeAnswers/UniqueAnswers // counters here we'll end up double-incrementing them when we do it again in AnswerNewQuestion(). for (q = m->Questions; q && q != m->NewQuestions; q=q->next) { if (ResourceRecordAnswersQuestion(&rr->resrec, q)) { // If this question is one that's actively sending queries, and it's received ten answers within one // second of sending the last query packet, then that indicates some radical network topology change, // so reset its exponential backoff back to the start. We must be at least at the eight-second interval // to do this. If we're at the four-second interval, or less, there's not much benefit accelerating // because we will anyway send another query within a few seconds. The first reset query is sent out // randomized over the next four seconds to reduce possible synchronization between machines. if (q->LastAnswerPktNum != m->PktNum) { q->LastAnswerPktNum = m->PktNum; if (mDNSOpaque16IsZero(q->TargetQID) && ActiveQuestion(q) && ++q->RecentAnswerPkts >= 10 && q->ThisQInterval > InitialQuestionInterval * QuestionIntervalStep3 && m->timenow - q->LastQTxTime < mDNSPlatformOneSecond) { LogMsg("CacheRecordAdd: %##s (%s) got immediate answer burst (%d); restarting exponential backoff sequence (%d)", q->qname.c, DNSTypeName(q->qtype), q->RecentAnswerPkts, q->ThisQInterval); q->LastQTime = m->timenow - InitialQuestionInterval + (mDNSs32)mDNSRandom((mDNSu32)mDNSPlatformOneSecond*4); q->ThisQInterval = InitialQuestionInterval; SetNextQueryTime(m,q); } } verbosedebugf("CacheRecordAdd %p %##s (%s) %lu %#a:%d question %p", rr, rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype), rr->resrec.rroriginalttl, rr->resrec.rDNSServer ? &rr->resrec.rDNSServer->addr : mDNSNULL, mDNSVal16(rr->resrec.rDNSServer ? rr->resrec.rDNSServer->port : zeroIPPort), q); q->CurrentAnswers++; q->unansweredQueries = 0; if (rr->resrec.rdlength > SmallRecordLimit) q->LargeAnswers++; if (rr->resrec.RecordType & kDNSRecordTypePacketUniqueMask) q->UniqueAnswers++; if (q->CurrentAnswers > 4000) { static int msgcount = 0; if (msgcount++ < 10) LogMsg("CacheRecordAdd: %##s (%s) has %d answers; shedding records to resist DOS attack", q->qname.c, DNSTypeName(q->qtype), q->CurrentAnswers); rr->resrec.rroriginalttl = 0; rr->UnansweredQueries = MaxUnansweredQueries; } } } if (!rr->DelayDelivery) { if (m->CurrentQuestion) LogMsg("CacheRecordAdd ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = m->Questions; while (m->CurrentQuestion && m->CurrentQuestion != m->NewQuestions) { q = m->CurrentQuestion; if (ResourceRecordAnswersQuestion(&rr->resrec, q)) AnswerCurrentQuestionWithResourceRecord(m, rr, QC_add); if (m->CurrentQuestion == q) // If m->CurrentQuestion was not auto-advanced, do it ourselves now m->CurrentQuestion = q->next; } m->CurrentQuestion = mDNSNULL; } SetNextCacheCheckTimeForRecord(m, rr); } // NoCacheAnswer is only called from mDNSCoreReceiveResponse, *never* directly as a result of a client API call. // If new questions are created as a result of invoking client callbacks, they will be added to // the end of the question list, and m->NewQuestions will be set to indicate the first new question. // rr is a new CacheRecord just received from the wire (kDNSRecordTypePacketAns/AnsUnique/Add/AddUnique) // but we don't have any place to cache it. We'll deliver question 'add' events now, but we won't have any // way to deliver 'remove' events in future, nor will we be able to include this in known-answer lists, // so we immediately bump ThisQInterval up to MaxQuestionInterval to avoid pounding the network. // Note: NoCacheAnswer calls AnswerCurrentQuestionWithResourceRecord which can call a user callback, // which may change the record list and/or question list. // Any code walking either list must use the CurrentQuestion and/or CurrentRecord mechanism to protect against this. mDNSlocal void NoCacheAnswer(mDNS *const m, CacheRecord *rr) { LogMsg("No cache space: Delivering non-cached result for %##s", m->rec.r.resrec.name->c); if (m->CurrentQuestion) LogMsg("NoCacheAnswer ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = m->Questions; // We do this for *all* questions, not stopping when we get to m->NewQuestions, // since we're not caching the record and we'll get no opportunity to do this later while (m->CurrentQuestion) { DNSQuestion *q = m->CurrentQuestion; if (ResourceRecordAnswersQuestion(&rr->resrec, q)) AnswerCurrentQuestionWithResourceRecord(m, rr, QC_addnocache); // QC_addnocache means "don't expect remove events for this" if (m->CurrentQuestion == q) // If m->CurrentQuestion was not auto-advanced, do it ourselves now m->CurrentQuestion = q->next; } m->CurrentQuestion = mDNSNULL; } // CacheRecordRmv is only called from CheckCacheExpiration, which is called from mDNS_Execute. // Note that CacheRecordRmv is *only* called for records that are referenced by at least one active question. // If new questions are created as a result of invoking client callbacks, they will be added to // the end of the question list, and m->NewQuestions will be set to indicate the first new question. // rr is an existing cache CacheRecord that just expired and is being deleted // (kDNSRecordTypePacketAns/PacketAnsUnique/PacketAdd/PacketAddUnique). // Note: CacheRecordRmv calls AnswerCurrentQuestionWithResourceRecord which can call a user callback, // which may change the record list and/or question list. // Any code walking either list must use the CurrentQuestion and/or CurrentRecord mechanism to protect against this. mDNSlocal void CacheRecordRmv(mDNS *const m, CacheRecord *rr) { if (m->CurrentQuestion) LogMsg("CacheRecordRmv ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = m->Questions; // We stop when we get to NewQuestions -- for new questions their CurrentAnswers/LargeAnswers/UniqueAnswers counters // will all still be zero because we haven't yet gone through the cache counting how many answers we have for them. while (m->CurrentQuestion && m->CurrentQuestion != m->NewQuestions) { DNSQuestion *q = m->CurrentQuestion; // When a question enters suppressed state, we generate RMV events and generate a negative // response. A cache may be present that answers this question e.g., cache entry generated // before the question became suppressed. We need to skip the suppressed questions here as // the RMV event has already been generated. if (!QuerySuppressed(q) && ResourceRecordAnswersQuestion(&rr->resrec, q)) { verbosedebugf("CacheRecordRmv %p %s", rr, CRDisplayString(m, rr)); q->FlappingInterface1 = mDNSNULL; q->FlappingInterface2 = mDNSNULL; if (q->CurrentAnswers == 0) LogMsg("CacheRecordRmv ERROR!!: How can CurrentAnswers already be zero for %p %##s (%s) DNSServer %#a:%d", q, q->qname.c, DNSTypeName(q->qtype), q->qDNSServer ? &q->qDNSServer->addr : mDNSNULL, mDNSVal16(q->qDNSServer ? q->qDNSServer->port : zeroIPPort)); else { q->CurrentAnswers--; if (rr->resrec.rdlength > SmallRecordLimit) q->LargeAnswers--; if (rr->resrec.RecordType & kDNSRecordTypePacketUniqueMask) q->UniqueAnswers--; } // If we have dropped below the answer threshold for this mDNS question, // restart the queries at InitialQuestionInterval. if (mDNSOpaque16IsZero(q->TargetQID) && (q->BrowseThreshold > 0) && (q->CurrentAnswers < q->BrowseThreshold)) { q->ThisQInterval = InitialQuestionInterval; q->LastQTime = m->timenow - q->ThisQInterval; SetNextQueryTime(m,q); LogInfo("CacheRecordRmv: (%s) %##s dropped below threshold of %d answers", DNSTypeName(q->qtype), q->qname.c, q->BrowseThreshold); } if (rr->resrec.rdata->MaxRDLength) // Never generate "remove" events for negative results { if (q->CurrentAnswers == 0) { LogInfo("CacheRecordRmv: Last answer for %##s (%s) expired from cache; will reconfirm antecedents", q->qname.c, DNSTypeName(q->qtype)); ReconfirmAntecedents(m, &q->qname, q->qnamehash, 0); } AnswerCurrentQuestionWithResourceRecord(m, rr, QC_rmv); } } if (m->CurrentQuestion == q) // If m->CurrentQuestion was not auto-advanced, do it ourselves now m->CurrentQuestion = q->next; } m->CurrentQuestion = mDNSNULL; } mDNSlocal void ReleaseCacheEntity(mDNS *const m, CacheEntity *e) { #if APPLE_OSX_mDNSResponder && MACOSX_MDNS_MALLOC_DEBUGGING >= 1 unsigned int i; for (i=0; inext = m->rrcache_free; m->rrcache_free = e; m->rrcache_totalused--; } mDNSlocal void ReleaseCacheGroup(mDNS *const m, CacheGroup **cp) { CacheEntity *e = (CacheEntity *)(*cp); //LogMsg("ReleaseCacheGroup: Releasing CacheGroup for %p, %##s", (*cp)->name->c, (*cp)->name->c); if ((*cp)->rrcache_tail != &(*cp)->members) LogMsg("ERROR: (*cp)->members == mDNSNULL but (*cp)->rrcache_tail != &(*cp)->members)"); //if ((*cp)->name != (domainname*)((*cp)->namestorage)) // LogMsg("ReleaseCacheGroup: %##s, %p %p", (*cp)->name->c, (*cp)->name, (domainname*)((*cp)->namestorage)); if ((*cp)->name != (domainname*)((*cp)->namestorage)) mDNSPlatformMemFree((*cp)->name); (*cp)->name = mDNSNULL; *cp = (*cp)->next; // Cut record from list ReleaseCacheEntity(m, e); } mDNSlocal void ReleaseAdditionalCacheRecords(mDNS *const m, CacheRecord **rp) { while (*rp) { CacheRecord *rr = *rp; *rp = (*rp)->next; // Cut record from list if (rr->resrec.rdata && rr->resrec.rdata != (RData*)&rr->smallrdatastorage) { mDNSPlatformMemFree(rr->resrec.rdata); rr->resrec.rdata = mDNSNULL; } // NSEC or SOA records that are not added to the CacheGroup do not share the name // of the CacheGroup. if (rr->resrec.name) { debugf("ReleaseAdditionalCacheRecords: freeing cached record %##s (%s)", rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype)); mDNSPlatformMemFree((void *)rr->resrec.name); rr->resrec.name = mDNSNULL; } // Don't count the NSEC3 records used by anonymous browse/reg if (!rr->resrec.InterfaceID) { m->rrcache_totalused_unicast -= rr->resrec.rdlength; if (DNSSECRecordType(rr->resrec.rrtype)) BumpDNSSECStats(m, kStatsActionDecrement, kStatsTypeMemoryUsage, rr->resrec.rdlength); } ReleaseCacheEntity(m, (CacheEntity *)rr); } } mDNSexport void ReleaseCacheRecord(mDNS *const m, CacheRecord *r) { CacheGroup *cg; //LogMsg("ReleaseCacheRecord: Releasing %s", CRDisplayString(m, r)); if (r->resrec.rdata && r->resrec.rdata != (RData*)&r->smallrdatastorage) mDNSPlatformMemFree(r->resrec.rdata); r->resrec.rdata = mDNSNULL; cg = CacheGroupForRecord(m, &r->resrec); if (!cg) { // It is okay to have this printed for NSEC/NSEC3s LogInfo("ReleaseCacheRecord: ERROR!! cg NULL for %##s (%s)", r->resrec.name->c, DNSTypeName(r->resrec.rrtype)); } // When NSEC records are not added to the cache, it is usually cached at the "nsec" list // of the CacheRecord. But sometimes they may be freed without adding to the "nsec" list // (which is handled below) and in that case it should be freed here. if (r->resrec.name && cg && r->resrec.name != cg->name) { debugf("ReleaseCacheRecord: freeing %##s (%s)", r->resrec.name->c, DNSTypeName(r->resrec.rrtype)); mDNSPlatformMemFree((void *)r->resrec.name); } r->resrec.name = mDNSNULL; if (r->resrec.AnonInfo) { debugf("ReleaseCacheRecord: freeing AnonInfo for %##s (%s)", r->resrec.name->c, DNSTypeName(r->resrec.rrtype)); FreeAnonInfo((void *)r->resrec.AnonInfo); } r->resrec.AnonInfo = mDNSNULL; if (!r->resrec.InterfaceID) { m->rrcache_totalused_unicast -= r->resrec.rdlength; if (DNSSECRecordType(r->resrec.rrtype)) BumpDNSSECStats(m, kStatsActionDecrement, kStatsTypeMemoryUsage, r->resrec.rdlength); } ReleaseAdditionalCacheRecords(m, &r->nsec); ReleaseAdditionalCacheRecords(m, &r->soa); ReleaseCacheEntity(m, (CacheEntity *)r); } // Note: We want to be careful that we deliver all the CacheRecordRmv calls before delivering // CacheRecordDeferredAdd calls. The in-order nature of the cache lists ensures that all // callbacks for old records are delivered before callbacks for newer records. mDNSlocal void CheckCacheExpiration(mDNS *const m, const mDNSu32 slot, CacheGroup *const cg) { CacheRecord **rp = &cg->members; if (m->lock_rrcache) { LogMsg("CheckCacheExpiration ERROR! Cache already locked!"); return; } m->lock_rrcache = 1; while (*rp) { CacheRecord *const rr = *rp; mDNSs32 event = RRExpireTime(rr); if (m->timenow - event >= 0) // If expired, delete it { *rp = rr->next; // Cut it from the list verbosedebugf("CheckCacheExpiration: Deleting%7d %7d %p %s", m->timenow - rr->TimeRcvd, rr->resrec.rroriginalttl, rr->CRActiveQuestion, CRDisplayString(m, rr)); if (rr->CRActiveQuestion) // If this record has one or more active questions, tell them it's going away { DNSQuestion *q = rr->CRActiveQuestion; // When a cache record is about to expire, we expect to do four queries at 80-82%, 85-87%, 90-92% and // then 95-97% of the TTL. If the DNS server does not respond, then we will remove the cache entry // before we pick a new DNS server. As the question interval is set to MaxQuestionInterval, we may // not send out a query anytime soon. Hence, we need to reset the question interval. If this is // a normal deferred ADD case, then AnswerCurrentQuestionWithResourceRecord will reset it to // MaxQuestionInterval. If we have inactive questions referring to negative cache entries, // don't ressurect them as they will deliver duplicate "No such Record" ADD events if (!mDNSOpaque16IsZero(q->TargetQID) && !q->LongLived && ActiveQuestion(q)) { q->ThisQInterval = InitialQuestionInterval; q->LastQTime = m->timenow - q->ThisQInterval; SetNextQueryTime(m, q); } CacheRecordRmv(m, rr); m->rrcache_active--; } ReleaseCacheRecord(m, rr); } else // else, not expired; see if we need to query { // If waiting to delay delivery, do nothing until then if (rr->DelayDelivery && rr->DelayDelivery - m->timenow > 0) event = rr->DelayDelivery; else { if (rr->DelayDelivery) CacheRecordDeferredAdd(m, rr); if (rr->CRActiveQuestion && rr->UnansweredQueries < MaxUnansweredQueries) { if (m->timenow - rr->NextRequiredQuery < 0) // If not yet time for next query event = NextCacheCheckEvent(rr); // then just record when we want the next query else // else trigger our question to go out now { // Set NextScheduledQuery to timenow so that SendQueries() will run. // SendQueries() will see that we have records close to expiration, and send FEQs for them. m->NextScheduledQuery = m->timenow; // After sending the query we'll increment UnansweredQueries and call SetNextCacheCheckTimeForRecord(), // which will correctly update m->NextCacheCheck for us. event = m->timenow + FutureTime; } } } verbosedebugf("CheckCacheExpiration:%6d %5d %s", (event - m->timenow) / mDNSPlatformOneSecond, CacheCheckGracePeriod(rr), CRDisplayString(m, rr)); if (m->rrcache_nextcheck[slot] - event > 0) m->rrcache_nextcheck[slot] = event; rp = &rr->next; } } if (cg->rrcache_tail != rp) verbosedebugf("CheckCacheExpiration: Updating CacheGroup tail from %p to %p", cg->rrcache_tail, rp); cg->rrcache_tail = rp; m->lock_rrcache = 0; } // "LORecord" includes both LocalOnly and P2P record. This function assumes m->CurrentQuestion is pointing to "q". // // If "CheckOnly" is set to "true", the question won't be answered but just check to see if there is an answer and // returns true if there is an answer. // // If "CheckOnly" is set to "false", the question will be answered if there is a LocalOnly/P2P record and // returns true to indicate the same. mDNSlocal mDNSBool AnswerQuestionWithLORecord(mDNS *const m, DNSQuestion *q, mDNSBool checkOnly) { AuthRecord *lr; AuthGroup *ag; if (m->CurrentRecord) LogMsg("AnswerQuestionWithLORecord ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); ag = AuthGroupForName(&m->rrauth, q->qnamehash, &q->qname); if (ag) { m->CurrentRecord = ag->members; while (m->CurrentRecord && m->CurrentRecord != ag->NewLocalOnlyRecords) { AuthRecord *rr = m->CurrentRecord; m->CurrentRecord = rr->next; // // If the question is mDNSInterface_LocalOnly, all records local to the machine should be used // to answer the query. This is handled in AnswerNewLocalOnlyQuestion. // // We handle mDNSInterface_Any and scoped questions here. See LocalOnlyRecordAnswersQuestion for more // details on how we handle this case. For P2P we just handle "Interface_Any" questions. For LocalOnly // we handle both mDNSInterface_Any and scoped questions. if (rr->ARType == AuthRecordLocalOnly || (rr->ARType == AuthRecordP2P && (q->InterfaceID == mDNSInterface_Any || q->InterfaceID == mDNSInterface_BLE))) if (LocalOnlyRecordAnswersQuestion(rr, q)) { if (checkOnly) { LogInfo("AnswerQuestionWithLORecord: question %##s (%s) answered by %s", q->qname.c, DNSTypeName(q->qtype), ARDisplayString(m, rr)); m->CurrentRecord = mDNSNULL; return mDNStrue; } AnswerLocalQuestionWithLocalAuthRecord(m, rr, mDNStrue); if (m->CurrentQuestion != q) break; // If callback deleted q, then we're finished here } } } m->CurrentRecord = mDNSNULL; if (m->CurrentQuestion != q) { LogInfo("AnswerQuestionWithLORecord: Question deleted while while answering LocalOnly record answers"); return mDNStrue; } if (q->LOAddressAnswers) { LogInfo("AnswerQuestionWithLORecord: Question %p %##s (%s) answered using local auth records LOAddressAnswers %d", q, q->qname.c, DNSTypeName(q->qtype), q->LOAddressAnswers); return mDNStrue; } // Before we go check the cache and ship this query on the wire, we have to be sure that there are // no local records that could possibly answer this question. As we did not check the NewLocalRecords, we // need to just peek at them to see whether it will answer this question. If it would answer, pretend // that we answered. AnswerAllLocalQuestionsWithLocalAuthRecord will answer shortly. This happens normally // when we add new /etc/hosts entries and restart the question. It is a new question and also a new record. if (ag) { lr = ag->NewLocalOnlyRecords; while (lr) { if (UniqueLocalOnlyRecord(lr) && LocalOnlyRecordAnswersQuestion(lr, q)) { LogInfo("AnswerQuestionWithLORecord: Question %p %##s (%s) will be answered using new local auth records " " LOAddressAnswers %d", q, q->qname.c, DNSTypeName(q->qtype), q->LOAddressAnswers); return mDNStrue; } lr = lr->next; } } return mDNSfalse; } // Today, we suppress questions (not send them on the wire) for several reasons e.g., // AAAA query is suppressed because no IPv6 capability or PID is not allowed to make // DNS requests. We need to temporarily suspend the suppress status so that we can // deliver a negative response (AnswerCurrentQuestionWithResourceRecord does not answer // suppressed questions) and reset it back. In the future, if there are other // reasons for suppressing the query, this function should be updated. mDNSlocal void AnswerSuppressedQuestion(mDNS *const m, DNSQuestion *q) { mDNSBool SuppressQuery; mDNSBool DisallowPID; // If the client did not set the kDNSServiceFlagsReturnIntermediates flag, then don't generate a negative response, just // deactivate the DNSQuestion. if (!q->ReturnIntermed) { q->ThisQInterval = 0; return; } SuppressQuery = q->SuppressQuery; DisallowPID = q->DisallowPID; // make sure that QuerySuppressed() returns false q->SuppressQuery = mDNSfalse; q->DisallowPID = mDNSfalse; GenerateNegativeResponse(m, mDNSInterface_Any, QC_suppressed); q->SuppressQuery = SuppressQuery; q->DisallowPID = DisallowPID; } mDNSlocal void AnswerNewQuestion(mDNS *const m) { mDNSBool ShouldQueryImmediately = mDNStrue; DNSQuestion *const q = m->NewQuestions; // Grab the question we're going to answer #if USE_DNS64 if (!mDNSOpaque16IsZero(q->TargetQID)) DNS64HandleNewQuestion(m, q); #endif CacheGroup *const cg = CacheGroupForName(m, q->qnamehash, &q->qname); mDNSBool AnsweredFromCache = mDNSfalse; verbosedebugf("AnswerNewQuestion: Answering %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); if (cg) CheckCacheExpiration(m, HashSlotFromNameHash(q->qnamehash), cg); if (m->NewQuestions != q) { LogInfo("AnswerNewQuestion: Question deleted while doing CheckCacheExpiration"); goto exit; } m->NewQuestions = q->next; // Advance NewQuestions to the next *after* calling CheckCacheExpiration, because if we advance it first // then CheckCacheExpiration may give this question add/remove callbacks, and it's not yet ready for that. // // Also, CheckCacheExpiration() calls CacheRecordDeferredAdd() and CacheRecordRmv(), which invoke // client callbacks, which may delete their own or any other question. Our mechanism for detecting // whether our current m->NewQuestions question got deleted by one of these callbacks is to store the // value of m->NewQuestions in 'q' before calling CheckCacheExpiration(), and then verify afterwards // that they're still the same. If m->NewQuestions has changed (because mDNS_StopQuery_internal // advanced it), that means the question was deleted, so we no longer need to worry about answering // it (and indeed 'q' is now a dangling pointer, so dereferencing it at all would be bad, and the // values we computed for slot and cg are now stale and relate to a question that no longer exists). // // We can't use the usual m->CurrentQuestion mechanism for this because CacheRecordDeferredAdd() and // CacheRecordRmv() both use that themselves when walking the list of (non-new) questions generating callbacks. // Fortunately mDNS_StopQuery_internal auto-advances both m->CurrentQuestion *AND* m->NewQuestions when // deleting a question, so luckily we have an easy alternative way of detecting if our question got deleted. if (m->lock_rrcache) LogMsg("AnswerNewQuestion ERROR! Cache already locked!"); // This should be safe, because calling the client's question callback may cause the // question list to be modified, but should not ever cause the rrcache list to be modified. // If the client's question callback deletes the question, then m->CurrentQuestion will // be advanced, and we'll exit out of the loop m->lock_rrcache = 1; if (m->CurrentQuestion) LogMsg("AnswerNewQuestion ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = q; // Indicate which question we're answering, so we'll know if it gets deleted if (q->NoAnswer == NoAnswer_Fail) { LogMsg("AnswerNewQuestion: NoAnswer_Fail %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); MakeNegativeCacheRecord(m, &m->rec.r, &q->qname, q->qnamehash, q->qtype, q->qclass, 60, mDNSInterface_Any, q->qDNSServer); q->NoAnswer = NoAnswer_Normal; // Temporarily turn off answer suppression AnswerCurrentQuestionWithResourceRecord(m, &m->rec.r, QC_addnocache); // Don't touch the question if it has been stopped already if (m->CurrentQuestion == q) q->NoAnswer = NoAnswer_Fail; // Restore NoAnswer state m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it } if (m->CurrentQuestion != q) { LogInfo("AnswerNewQuestion: Question deleted while generating NoAnswer_Fail response"); goto exit; } // See if we want to tell it about LocalOnly/P2P records. If we answered them using LocalOnly // or P2P record, then we are done. if (AnswerQuestionWithLORecord(m, q, mDNSfalse)) goto exit; // If we are not supposed to answer this question, generate a negative response. // Temporarily suspend the SuppressQuery so that AnswerCurrentQuestionWithResourceRecord can answer the question // // If it is a question trying to validate some response, it already checked the cache for a response. If it still // reissues a question it means it could not find the RRSIGs. So, we need to bypass the cache check and send // the question out. if (QuerySuppressed(q)) { AnswerSuppressedQuestion(m, q); } else if (!q->ValidatingResponse) { CacheRecord *rr; for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) if (SameNameRecordAnswersQuestion(&rr->resrec, q)) { // SecsSinceRcvd is whole number of elapsed seconds, rounded down mDNSu32 SecsSinceRcvd = ((mDNSu32)(m->timenow - rr->TimeRcvd)) / mDNSPlatformOneSecond; if (rr->resrec.rroriginalttl <= SecsSinceRcvd) { LogMsg("AnswerNewQuestion: How is rr->resrec.rroriginalttl %lu <= SecsSinceRcvd %lu for %s %d %d", rr->resrec.rroriginalttl, SecsSinceRcvd, CRDisplayString(m, rr), m->timenow, rr->TimeRcvd); continue; // Go to next one in loop } // If this record set is marked unique, then that means we can reasonably assume we have the whole set // -- we don't need to rush out on the network and query immediately to see if there are more answers out there if ((rr->resrec.RecordType & kDNSRecordTypePacketUniqueMask) || (q->ExpectUnique)) ShouldQueryImmediately = mDNSfalse; q->CurrentAnswers++; if (rr->resrec.rdlength > SmallRecordLimit) q->LargeAnswers++; if (rr->resrec.RecordType & kDNSRecordTypePacketUniqueMask) q->UniqueAnswers++; AnsweredFromCache = mDNStrue; AnswerCurrentQuestionWithResourceRecord(m, rr, QC_add); if (m->CurrentQuestion != q) break; // If callback deleted q, then we're finished here } else if (mDNSOpaque16IsZero(q->TargetQID) && RRTypeIsAddressType(rr->resrec.rrtype) && RRTypeIsAddressType(q->qtype)) ShouldQueryImmediately = mDNSfalse; } // We don't use LogInfo for this "Question deleted" message because it happens so routinely that // it's not remotely remarkable, and therefore unlikely to be of much help tracking down bugs. if (m->CurrentQuestion != q) { debugf("AnswerNewQuestion: Question deleted while giving cache answers"); goto exit; } // Neither a local record nor a cache entry could answer this question. If this question need to be retried // with search domains, generate a negative response which will now retry after appending search domains. // If the query was suppressed above, we already generated a negative response. When it gets unsuppressed, // we will retry with search domains. if (!QuerySuppressed(q) && !AnsweredFromCache && q->RetryWithSearchDomains) { LogInfo("AnswerNewQuestion: Generating response for retrying with search domains %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); GenerateNegativeResponse(m, mDNSInterface_Any, QC_forceresponse); } if (m->CurrentQuestion != q) { debugf("AnswerNewQuestion: Question deleted while giving negative answer"); goto exit; } // Note: When a query gets suppressed or retried with search domains, we de-activate the question. // Hence we don't execute the following block of code for those cases. if (ShouldQueryImmediately && ActiveQuestion(q)) { debugf("AnswerNewQuestion: ShouldQueryImmediately %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); q->ThisQInterval = InitialQuestionInterval; q->LastQTime = m->timenow - q->ThisQInterval; if (mDNSOpaque16IsZero(q->TargetQID)) // For mDNS, spread packets to avoid a burst of simultaneous queries { // Compute random delay in the range 1-6 seconds, then divide by 50 to get 20-120ms if (!m->RandomQueryDelay) m->RandomQueryDelay = (mDNSPlatformOneSecond + mDNSRandom(mDNSPlatformOneSecond*5) - 1) / 50 + 1; q->LastQTime += m->RandomQueryDelay; } } // IN ALL CASES make sure that m->NextScheduledQuery is set appropriately. // In cases where m->NewQuestions->DelayAnswering is set, we may have delayed generating our // answers for this question until *after* its scheduled transmission time, in which case // m->NextScheduledQuery may now be set to 'never', and in that case -- even though we're *not* doing // ShouldQueryImmediately -- we still need to make sure we set m->NextScheduledQuery correctly. SetNextQueryTime(m,q); exit: m->CurrentQuestion = mDNSNULL; m->lock_rrcache = 0; } // When a NewLocalOnlyQuestion is created, AnswerNewLocalOnlyQuestion runs though our ResourceRecords delivering any // appropriate answers, stopping if it reaches a NewLocalOnlyRecord -- these will be handled by AnswerAllLocalQuestionsWithLocalAuthRecord mDNSlocal void AnswerNewLocalOnlyQuestion(mDNS *const m) { AuthGroup *ag; DNSQuestion *q = m->NewLocalOnlyQuestions; // Grab the question we're going to answer mDNSBool retEv = mDNSfalse; m->NewLocalOnlyQuestions = q->next; // Advance NewLocalOnlyQuestions to the next (if any) debugf("AnswerNewLocalOnlyQuestion: Answering %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); if (m->CurrentQuestion) LogMsg("AnswerNewLocalOnlyQuestion ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = q; // Indicate which question we're answering, so we'll know if it gets deleted if (m->CurrentRecord) LogMsg("AnswerNewLocalOnlyQuestion ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); // 1. First walk the LocalOnly records answering the LocalOnly question // 2. As LocalOnly questions should also be answered by any other Auth records local to the machine, // walk the ResourceRecords list delivering the answers ag = AuthGroupForName(&m->rrauth, q->qnamehash, &q->qname); if (ag) { m->CurrentRecord = ag->members; while (m->CurrentRecord && m->CurrentRecord != ag->NewLocalOnlyRecords) { AuthRecord *rr = m->CurrentRecord; m->CurrentRecord = rr->next; if (LocalOnlyRecordAnswersQuestion(rr, q)) { retEv = mDNStrue; AnswerLocalQuestionWithLocalAuthRecord(m, rr, mDNStrue); if (m->CurrentQuestion != q) break; // If callback deleted q, then we're finished here } } } if (m->CurrentQuestion == q) { m->CurrentRecord = m->ResourceRecords; while (m->CurrentRecord && m->CurrentRecord != m->NewLocalRecords) { AuthRecord *rr = m->CurrentRecord; m->CurrentRecord = rr->next; if (ResourceRecordAnswersQuestion(&rr->resrec, q)) { retEv = mDNStrue; AnswerLocalQuestionWithLocalAuthRecord(m, rr, mDNStrue); if (m->CurrentQuestion != q) break; // If callback deleted q, then we're finished here } } } // The local host is the authoritative source for LocalOnly questions // so if no records exist and client requested intermediates, then generate a negative response if (!retEv && (m->CurrentQuestion == q) && q->ReturnIntermed) GenerateNegativeResponse(m, mDNSInterface_LocalOnly, QC_forceresponse); m->CurrentQuestion = mDNSNULL; m->CurrentRecord = mDNSNULL; } mDNSlocal CacheEntity *GetCacheEntity(mDNS *const m, const CacheGroup *const PreserveCG) { CacheEntity *e = mDNSNULL; if (m->lock_rrcache) { LogMsg("GetFreeCacheRR ERROR! Cache already locked!"); return(mDNSNULL); } m->lock_rrcache = 1; // If we have no free records, ask the client layer to give us some more memory if (!m->rrcache_free && m->MainCallback) { if (m->rrcache_totalused != m->rrcache_size) LogMsg("GetFreeCacheRR: count mismatch: m->rrcache_totalused %lu != m->rrcache_size %lu", m->rrcache_totalused, m->rrcache_size); // We don't want to be vulnerable to a malicious attacker flooding us with an infinite // number of bogus records so that we keep growing our cache until the machine runs out of memory. // To guard against this, if our cache grows above 512kB (approx 3168 records at 164 bytes each), // and we're actively using less than 1/32 of that cache, then we purge all the unused records // and recycle them, instead of allocating more memory. if (m->rrcache_size > 5000 && m->rrcache_size / 32 > m->rrcache_active) LogInfo("Possible denial-of-service attack in progress: m->rrcache_size %lu; m->rrcache_active %lu", m->rrcache_size, m->rrcache_active); else { mDNS_DropLockBeforeCallback(); // Allow client to legally make mDNS API calls from the callback m->MainCallback(m, mStatus_GrowCache); mDNS_ReclaimLockAfterCallback(); // Decrement mDNS_reentrancy to block mDNS API calls again } } // If we still have no free records, recycle all the records we can. // Enumerating the entire cache is moderately expensive, so when we do it, we reclaim all the records we can in one pass. if (!m->rrcache_free) { mDNSu32 oldtotalused = m->rrcache_totalused; mDNSu32 slot; for (slot = 0; slot < CACHE_HASH_SLOTS; slot++) { CacheGroup **cp = &m->rrcache_hash[slot]; while (*cp) { CacheRecord **rp = &(*cp)->members; while (*rp) { // Records that answer still-active questions are not candidates for recycling // Records that are currently linked into the CacheFlushRecords list may not be recycled, or we'll crash if ((*rp)->CRActiveQuestion || (*rp)->NextInCFList) rp=&(*rp)->next; else { CacheRecord *rr = *rp; *rp = (*rp)->next; // Cut record from list ReleaseCacheRecord(m, rr); } } if ((*cp)->rrcache_tail != rp) verbosedebugf("GetFreeCacheRR: Updating rrcache_tail[%lu] from %p to %p", slot, (*cp)->rrcache_tail, rp); (*cp)->rrcache_tail = rp; if ((*cp)->members || (*cp)==PreserveCG) cp=&(*cp)->next; else ReleaseCacheGroup(m, cp); } } LogInfo("GetCacheEntity recycled %d records to reduce cache from %d to %d", oldtotalused - m->rrcache_totalused, oldtotalused, m->rrcache_totalused); } if (m->rrcache_free) // If there are records in the free list, take one { e = m->rrcache_free; m->rrcache_free = e->next; if (++m->rrcache_totalused >= m->rrcache_report) { LogInfo("RR Cache now using %ld objects", m->rrcache_totalused); if (m->rrcache_report < 100) m->rrcache_report += 10; else if (m->rrcache_report < 1000) m->rrcache_report += 100; else m->rrcache_report += 1000; } mDNSPlatformMemZero(e, sizeof(*e)); } m->lock_rrcache = 0; return(e); } mDNSlocal CacheRecord *GetCacheRecord(mDNS *const m, CacheGroup *cg, mDNSu16 RDLength) { CacheRecord *r = (CacheRecord *)GetCacheEntity(m, cg); if (r) { r->resrec.rdata = (RData*)&r->smallrdatastorage; // By default, assume we're usually going to be using local storage if (RDLength > InlineCacheRDSize) // If RDLength is too big, allocate extra storage { r->resrec.rdata = (RData*)mDNSPlatformMemAllocate(sizeofRDataHeader + RDLength); if (r->resrec.rdata) r->resrec.rdata->MaxRDLength = r->resrec.rdlength = RDLength; else { ReleaseCacheEntity(m, (CacheEntity*)r); r = mDNSNULL; } } } return(r); } mDNSlocal CacheGroup *GetCacheGroup(mDNS *const m, const mDNSu32 slot, const ResourceRecord *const rr) { mDNSu16 namelen = DomainNameLength(rr->name); CacheGroup *cg = (CacheGroup*)GetCacheEntity(m, mDNSNULL); if (!cg) { LogMsg("GetCacheGroup: Failed to allocate memory for %##s", rr->name->c); return(mDNSNULL); } cg->next = m->rrcache_hash[slot]; cg->namehash = rr->namehash; cg->members = mDNSNULL; cg->rrcache_tail = &cg->members; if (namelen > sizeof(cg->namestorage)) cg->name = mDNSPlatformMemAllocate(namelen); else cg->name = (domainname*)cg->namestorage; if (!cg->name) { LogMsg("GetCacheGroup: Failed to allocate name storage for %##s", rr->name->c); ReleaseCacheEntity(m, (CacheEntity*)cg); return(mDNSNULL); } AssignDomainName(cg->name, rr->name); if (CacheGroupForRecord(m, rr)) LogMsg("GetCacheGroup: Already have CacheGroup for %##s", rr->name->c); m->rrcache_hash[slot] = cg; if (CacheGroupForRecord(m, rr) != cg) LogMsg("GetCacheGroup: Not finding CacheGroup for %##s", rr->name->c); return(cg); } mDNSexport void mDNS_PurgeCacheResourceRecord(mDNS *const m, CacheRecord *rr) { mDNS_CheckLock(m); // Make sure we mark this record as thoroughly expired -- we don't ever want to give // a positive answer using an expired record (e.g. from an interface that has gone away). // We don't want to clear CRActiveQuestion here, because that would leave the record subject to // summary deletion without giving the proper callback to any questions that are monitoring it. // By setting UnansweredQueries to MaxUnansweredQueries we ensure it won't trigger any further expiration queries. rr->TimeRcvd = m->timenow - mDNSPlatformOneSecond * 60; rr->UnansweredQueries = MaxUnansweredQueries; rr->resrec.rroriginalttl = 0; SetNextCacheCheckTimeForRecord(m, rr); } mDNSexport mDNSs32 mDNS_TimeNow(const mDNS *const m) { mDNSs32 time; mDNSPlatformLock(m); if (m->mDNS_busy) { LogMsg("mDNS_TimeNow called while holding mDNS lock. This is incorrect. Code protected by lock should just use m->timenow."); if (!m->timenow) LogMsg("mDNS_TimeNow: m->mDNS_busy is %ld but m->timenow not set", m->mDNS_busy); } if (m->timenow) time = m->timenow; else time = mDNS_TimeNow_NoLock(m); mDNSPlatformUnlock(m); return(time); } // To avoid pointless CPU thrash, we use SetSPSProxyListChanged(X) to record the last interface that // had its Sleep Proxy client list change, and defer to actual BPF reconfiguration to mDNS_Execute(). // (GetNextScheduledEvent() returns "now" when m->SPSProxyListChanged is set) #define SetSPSProxyListChanged(X) do { \ if (m->SPSProxyListChanged && m->SPSProxyListChanged != (X)) mDNSPlatformUpdateProxyList(m->SPSProxyListChanged); \ m->SPSProxyListChanged = (X); } while(0) // Called from mDNS_Execute() to expire stale proxy records mDNSlocal void CheckProxyRecords(mDNS *const m, AuthRecord *list) { m->CurrentRecord = list; while (m->CurrentRecord) { AuthRecord *rr = m->CurrentRecord; if (rr->resrec.RecordType != kDNSRecordTypeDeregistering && rr->WakeUp.HMAC.l[0]) { // If m->SPSSocket is NULL that means we're not acting as a sleep proxy any more, // so we need to cease proxying for *all* records we may have, expired or not. if (m->SPSSocket && m->timenow - rr->TimeExpire < 0) // If proxy record not expired yet, update m->NextScheduledSPS { if (m->NextScheduledSPS - rr->TimeExpire > 0) m->NextScheduledSPS = rr->TimeExpire; } else // else proxy record expired, so remove it { LogSPS("CheckProxyRecords: Removing %d H-MAC %.6a I-MAC %.6a %d %s", m->ProxyRecords, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, rr->WakeUp.seq, ARDisplayString(m, rr)); SetSPSProxyListChanged(rr->resrec.InterfaceID); mDNS_Deregister_internal(m, rr, mDNS_Dereg_normal); // Don't touch rr after this -- memory may have been free'd } } // Mustn't advance m->CurrentRecord until *after* mDNS_Deregister_internal, because // new records could have been added to the end of the list as a result of that call. if (m->CurrentRecord == rr) // If m->CurrentRecord was not advanced for us, do it now m->CurrentRecord = rr->next; } } mDNSlocal void CheckRmvEventsForLocalRecords(mDNS *const m) { while (m->CurrentRecord) { AuthRecord *rr = m->CurrentRecord; if (rr->AnsweredLocalQ && rr->resrec.RecordType == kDNSRecordTypeDeregistering) { debugf("CheckRmvEventsForLocalRecords: Generating local RMV events for %s", ARDisplayString(m, rr)); rr->resrec.RecordType = kDNSRecordTypeShared; AnswerAllLocalQuestionsWithLocalAuthRecord(m, rr, mDNSfalse); if (m->CurrentRecord == rr) // If rr still exists in list, restore its state now { rr->resrec.RecordType = kDNSRecordTypeDeregistering; rr->AnsweredLocalQ = mDNSfalse; // SendResponses normally calls CompleteDeregistration after sending goodbyes. // For LocalOnly records, we don't do that and hence we need to do that here. if (RRLocalOnly(rr)) CompleteDeregistration(m, rr); } } if (m->CurrentRecord == rr) // If m->CurrentRecord was not auto-advanced, do it ourselves now m->CurrentRecord = rr->next; } } mDNSlocal void TimeoutQuestions_internal(mDNS *const m, DNSQuestion* questions, mDNSInterfaceID InterfaceID) { if (m->CurrentQuestion) LogMsg("TimeoutQuestions ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = questions; while (m->CurrentQuestion) { DNSQuestion *const q = m->CurrentQuestion; if (q->StopTime) { if (!q->TimeoutQuestion) LogMsg("TimeoutQuestions: ERROR!! TimeoutQuestion not set, but StopTime set for %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); if (m->timenow - q->StopTime >= 0) { LogInfo("TimeoutQuestions: question %p %##s timed out, time %d", q, q->qname.c, m->timenow - q->StopTime); q->LOAddressAnswers = 0; // unset since timing out the question GenerateNegativeResponse(m, InterfaceID, QC_forceresponse); if (m->CurrentQuestion == q) q->StopTime = 0; } else { if (m->NextScheduledStopTime - q->StopTime > 0) m->NextScheduledStopTime = q->StopTime; } } // If m->CurrentQuestion wasn't modified out from under us, advance it now // We can't do this at the start of the loop because GenerateNegativeResponse // depends on having m->CurrentQuestion point to the right question if (m->CurrentQuestion == q) m->CurrentQuestion = q->next; } m->CurrentQuestion = mDNSNULL; } mDNSlocal void TimeoutQuestions(mDNS *const m) { m->NextScheduledStopTime = m->timenow + FutureTime; // push reschedule of TimeoutQuestions to way off into the future TimeoutQuestions_internal(m, m->Questions, mDNSInterface_Any); TimeoutQuestions_internal(m, m->LocalOnlyQuestions, mDNSInterface_LocalOnly); } mDNSlocal void mDNSCoreFreeProxyRR(mDNS *const m) { AuthRecord *rrPtr = m->SPSRRSet, *rrNext = mDNSNULL; LogSPS("%s : Freeing stored sleep proxy A/AAAA records", __func__); while (rrPtr) { rrNext = rrPtr->next; mDNSPlatformMemFree(rrPtr); rrPtr = rrNext; } m->SPSRRSet = mDNSNULL; } mDNSexport mDNSs32 mDNS_Execute(mDNS *const m) { mDNS_Lock(m); // Must grab lock before trying to read m->timenow if (m->timenow - m->NextScheduledEvent >= 0) { int i; AuthRecord *head, *tail; mDNSu32 slot; AuthGroup *ag; verbosedebugf("mDNS_Execute"); if (m->CurrentQuestion) LogMsg("mDNS_Execute: ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); if (m->CurrentRecord) LogMsg("mDNS_Execute: ERROR m->CurrentRecord already set: %s", ARDisplayString(m, m->CurrentRecord)); // 1. If we're past the probe suppression time, we can clear it if (m->SuppressProbes && m->timenow - m->SuppressProbes >= 0) m->SuppressProbes = 0; // 2. If it's been more than ten seconds since the last probe failure, we can clear the counter if (m->NumFailedProbes && m->timenow - m->ProbeFailTime >= mDNSPlatformOneSecond * 10) m->NumFailedProbes = 0; // 3. Purge our cache of stale old records if (m->rrcache_size && m->timenow - m->NextCacheCheck >= 0) { mDNSu32 numchecked = 0; m->NextCacheCheck = m->timenow + FutureTime; for (slot = 0; slot < CACHE_HASH_SLOTS; slot++) { if (m->timenow - m->rrcache_nextcheck[slot] >= 0) { CacheGroup **cp = &m->rrcache_hash[slot]; m->rrcache_nextcheck[slot] = m->timenow + FutureTime; while (*cp) { debugf("m->NextCacheCheck %4d Slot %3d %##s", numchecked, slot, *cp ? (*cp)->name : (domainname*)"\x04NULL"); numchecked++; CheckCacheExpiration(m, slot, *cp); if ((*cp)->members) cp=&(*cp)->next; else ReleaseCacheGroup(m, cp); } } // Even if we didn't need to actually check this slot yet, still need to // factor its nextcheck time into our overall NextCacheCheck value if (m->NextCacheCheck - m->rrcache_nextcheck[slot] > 0) m->NextCacheCheck = m->rrcache_nextcheck[slot]; } debugf("m->NextCacheCheck %4d checked, next in %d", numchecked, m->NextCacheCheck - m->timenow); } if (m->timenow - m->NextScheduledSPS >= 0) { m->NextScheduledSPS = m->timenow + FutureTime; CheckProxyRecords(m, m->DuplicateRecords); // Clear m->DuplicateRecords first, then m->ResourceRecords CheckProxyRecords(m, m->ResourceRecords); } SetSPSProxyListChanged(mDNSNULL); // Perform any deferred BPF reconfiguration now // Check to see if we need to send any keepalives. Do this after we called CheckProxyRecords above // as records could have expired during that check if (m->timenow - m->NextScheduledKA >= 0) { m->NextScheduledKA = m->timenow + FutureTime; mDNS_SendKeepalives(m); } #if BONJOUR_ON_DEMAND if (m->NextBonjourDisableTime && (m->timenow - m->NextBonjourDisableTime >= 0)) { // Schedule immediate network change processing to leave the multicast group // since the delay time has expired since the previous active registration or query. m->NetworkChanged = m->timenow; m->NextBonjourDisableTime = 0; m->BonjourEnabled = 0; LogInfo("mDNS_Execute: Scheduled network changed processing to leave multicast group."); } #endif // BONJOUR_ON_DEMAND // Clear AnnounceOwner if necessary. (Do this *before* SendQueries() and SendResponses().) if (m->AnnounceOwner && m->timenow - m->AnnounceOwner >= 0) { m->AnnounceOwner = 0; // This is a good time to reset the delay counter used to prevent spurious conflicts m->DelayConflictProcessing = 0; } if (m->DelaySleep && m->timenow - m->DelaySleep >= 0) { m->DelaySleep = 0; if (m->SleepState == SleepState_Transferring) { LogSPS("Re-sleep delay passed; now checking for Sleep Proxy Servers"); BeginSleepProcessing(m); } } // 4. See if we can answer any of our new local questions from the cache for (i=0; m->NewQuestions && i<1000; i++) { if (m->NewQuestions->DelayAnswering && m->timenow - m->NewQuestions->DelayAnswering < 0) break; AnswerNewQuestion(m); } if (i >= 1000) LogMsg("mDNS_Execute: AnswerNewQuestion exceeded loop limit"); // Make sure we deliver *all* local RMV events, and clear the corresponding rr->AnsweredLocalQ flags, *before* // we begin generating *any* new ADD events in the m->NewLocalOnlyQuestions and m->NewLocalRecords loops below. for (i=0; i<1000 && m->LocalRemoveEvents; i++) { m->LocalRemoveEvents = mDNSfalse; m->CurrentRecord = m->ResourceRecords; CheckRmvEventsForLocalRecords(m); // Walk the LocalOnly records and deliver the RMV events for (slot = 0; slot < AUTH_HASH_SLOTS; slot++) for (ag = m->rrauth.rrauth_hash[slot]; ag; ag = ag->next) { m->CurrentRecord = ag->members; if (m->CurrentRecord) CheckRmvEventsForLocalRecords(m); } } if (i >= 1000) LogMsg("mDNS_Execute: m->LocalRemoveEvents exceeded loop limit"); for (i=0; m->NewLocalOnlyQuestions && i<1000; i++) AnswerNewLocalOnlyQuestion(m); if (i >= 1000) LogMsg("mDNS_Execute: AnswerNewLocalOnlyQuestion exceeded loop limit"); head = tail = mDNSNULL; for (i=0; i<1000 && m->NewLocalRecords && m->NewLocalRecords != head; i++) { AuthRecord *rr = m->NewLocalRecords; m->NewLocalRecords = m->NewLocalRecords->next; if (LocalRecordReady(rr)) { debugf("mDNS_Execute: Delivering Add event with LocalAuthRecord %s", ARDisplayString(m, rr)); AnswerAllLocalQuestionsWithLocalAuthRecord(m, rr, mDNStrue); } else if (!rr->next) { // If we have just one record that is not ready, we don't have to unlink and // reinsert. As the NewLocalRecords will be NULL for this case, the loop will // terminate and set the NewLocalRecords to rr. debugf("mDNS_Execute: Just one LocalAuthRecord %s, breaking out of the loop early", ARDisplayString(m, rr)); if (head != mDNSNULL || m->NewLocalRecords != mDNSNULL) LogMsg("mDNS_Execute: ERROR!!: head %p, NewLocalRecords %p", head, m->NewLocalRecords); head = rr; } else { AuthRecord **p = &m->ResourceRecords; // Find this record in our list of active records debugf("mDNS_Execute: Skipping LocalAuthRecord %s", ARDisplayString(m, rr)); // if this is the first record we are skipping, move to the end of the list. // if we have already skipped records before, append it at the end. while (*p && *p != rr) p=&(*p)->next; if (*p) *p = rr->next; // Cut this record from the list else { LogMsg("mDNS_Execute: ERROR!! Cannot find record %s in ResourceRecords list", ARDisplayString(m, rr)); break; } if (!head) { while (*p) p=&(*p)->next; *p = rr; head = tail = rr; } else { tail->next = rr; tail = rr; } rr->next = mDNSNULL; } } m->NewLocalRecords = head; debugf("mDNS_Execute: Setting NewLocalRecords to %s", (head ? ARDisplayString(m, head) : "NULL")); if (i >= 1000) LogMsg("mDNS_Execute: m->NewLocalRecords exceeded loop limit"); // Check to see if we have any new LocalOnly/P2P records to examine for delivering // to our local questions if (m->NewLocalOnlyRecords) { m->NewLocalOnlyRecords = mDNSfalse; for (slot = 0; slot < AUTH_HASH_SLOTS; slot++) for (ag = m->rrauth.rrauth_hash[slot]; ag; ag = ag->next) { for (i=0; i<100 && ag->NewLocalOnlyRecords; i++) { AuthRecord *rr = ag->NewLocalOnlyRecords; ag->NewLocalOnlyRecords = ag->NewLocalOnlyRecords->next; // LocalOnly records should always be ready as they never probe if (LocalRecordReady(rr)) { debugf("mDNS_Execute: Delivering Add event with LocalAuthRecord %s", ARDisplayString(m, rr)); AnswerAllLocalQuestionsWithLocalAuthRecord(m, rr, mDNStrue); } else LogMsg("mDNS_Execute: LocalOnlyRecord %s not ready", ARDisplayString(m, rr)); } // We limit about 100 per AuthGroup that can be serviced at a time if (i >= 100) LogMsg("mDNS_Execute: ag->NewLocalOnlyRecords exceeded loop limit"); } } // 5. See what packets we need to send if (m->mDNSPlatformStatus != mStatus_NoError || (m->SleepState == SleepState_Sleeping)) DiscardDeregistrations(m); if (m->mDNSPlatformStatus == mStatus_NoError && (m->SuppressSending == 0 || m->timenow - m->SuppressSending >= 0)) { // If the platform code is ready, and we're not suppressing packet generation right now // then send our responses, probes, and questions. // We check the cache first, because there might be records close to expiring that trigger questions to refresh them. // We send queries next, because there might be final-stage probes that complete their probing here, causing // them to advance to announcing state, and we want those to be included in any announcements we send out. // Finally, we send responses, including the previously mentioned records that just completed probing. m->SuppressSending = 0; // 6. Send Query packets. This may cause some probing records to advance to announcing state if (m->timenow - m->NextScheduledQuery >= 0 || m->timenow - m->NextScheduledProbe >= 0) SendQueries(m); if (m->timenow - m->NextScheduledQuery >= 0) { DNSQuestion *q; LogMsg("mDNS_Execute: SendQueries didn't send all its queries (%d - %d = %d) will try again in one second", m->timenow, m->NextScheduledQuery, m->timenow - m->NextScheduledQuery); m->NextScheduledQuery = m->timenow + mDNSPlatformOneSecond; for (q = m->Questions; q && q != m->NewQuestions; q=q->next) if (ActiveQuestion(q) && m->timenow - NextQSendTime(q) >= 0) LogMsg("mDNS_Execute: SendQueries didn't send %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); } if (m->timenow - m->NextScheduledProbe >= 0) { LogMsg("mDNS_Execute: SendQueries didn't send all its probes (%d - %d = %d) will try again in one second", m->timenow, m->NextScheduledProbe, m->timenow - m->NextScheduledProbe); m->NextScheduledProbe = m->timenow + mDNSPlatformOneSecond; } // 7. Send Response packets, including probing records just advanced to announcing state if (m->timenow - m->NextScheduledResponse >= 0) SendResponses(m); if (m->timenow - m->NextScheduledResponse >= 0) { LogMsg("mDNS_Execute: SendResponses didn't send all its responses; will try again in one second"); m->NextScheduledResponse = m->timenow + mDNSPlatformOneSecond; } } // Clear RandomDelay values, ready to pick a new different value next time m->RandomQueryDelay = 0; m->RandomReconfirmDelay = 0; // See if any questions (or local-only questions) have timed out if (m->NextScheduledStopTime && m->timenow - m->NextScheduledStopTime >= 0) TimeoutQuestions(m); #ifndef UNICAST_DISABLED if (m->NextSRVUpdate && m->timenow - m->NextSRVUpdate >= 0) UpdateAllSRVRecords(m); if (m->timenow - m->NextScheduledNATOp >= 0) CheckNATMappings(m); if (m->timenow - m->NextuDNSEvent >= 0) uDNS_Tasks(m); #endif #if APPLE_OSX_mDNSResponder && ENABLE_BLE_TRIGGERED_BONJOUR extern void serviceBLE(); if (m->NextBLEServiceTime && (m->timenow - m->NextBLEServiceTime >= 0)) serviceBLE(); #endif // APPLE_OSX_mDNSResponder && ENABLE_BLE_TRIGGERED_BONJOUR } // Note about multi-threaded systems: // On a multi-threaded system, some other thread could run right after the mDNS_Unlock(), // performing mDNS API operations that change our next scheduled event time. // // On multi-threaded systems (like the current Windows implementation) that have a single main thread // calling mDNS_Execute() (and other threads allowed to call mDNS API routines) it is the responsibility // of the mDNSPlatformUnlock() routine to signal some kind of stateful condition variable that will // signal whatever blocking primitive the main thread is using, so that it will wake up and execute one // more iteration of its loop, and immediately call mDNS_Execute() again. The signal has to be stateful // in the sense that if the main thread has not yet entered its blocking primitive, then as soon as it // does, the state of the signal will be noticed, causing the blocking primitive to return immediately // without blocking. This avoids the race condition between the signal from the other thread arriving // just *before* or just *after* the main thread enters the blocking primitive. // // On multi-threaded systems (like the current Mac OS 9 implementation) that are entirely timer-driven, // with no main mDNS_Execute() thread, it is the responsibility of the mDNSPlatformUnlock() routine to // set the timer according to the m->NextScheduledEvent value, and then when the timer fires, the timer // callback function should call mDNS_Execute() (and ignore the return value, which may already be stale // by the time it gets to the timer callback function). mDNS_Unlock(m); // Calling mDNS_Unlock is what gives m->NextScheduledEvent its new value return(m->NextScheduledEvent); } #ifndef UNICAST_DISABLED mDNSlocal void SuspendLLQs(mDNS *m) { DNSQuestion *q; for (q = m->Questions; q; q = q->next) if (ActiveQuestion(q) && !mDNSOpaque16IsZero(q->TargetQID) && q->LongLived && q->state == LLQ_Established) { q->ReqLease = 0; sendLLQRefresh(m, q); } } #endif // UNICAST_DISABLED mDNSlocal mDNSBool QuestionHasLocalAnswers(mDNS *const m, DNSQuestion *q) { AuthRecord *rr; AuthGroup *ag; ag = AuthGroupForName(&m->rrauth, q->qnamehash, &q->qname); if (ag) { for (rr = ag->members; rr; rr=rr->next) // Filter the /etc/hosts records - LocalOnly, Unique, A/AAAA/CNAME if (UniqueLocalOnlyRecord(rr) && LocalOnlyRecordAnswersQuestion(rr, q)) { LogInfo("QuestionHasLocalAnswers: Question %p %##s (%s) has local answer %s", q, q->qname.c, DNSTypeName(q->qtype), ARDisplayString(m, rr)); return mDNStrue; } } return mDNSfalse; } // ActivateUnicastQuery() is called from three places: // 1. When a new question is created // 2. On wake from sleep // 3. When the DNS configuration changes // In case 1 we don't want to mess with our established ThisQInterval and LastQTime (ScheduleImmediately is false) // In cases 2 and 3 we do want to cause the question to be resent immediately (ScheduleImmediately is true) mDNSlocal void ActivateUnicastQuery(mDNS *const m, DNSQuestion *const question, mDNSBool ScheduleImmediately) { // For now this AutoTunnel stuff is specific to Mac OS X. // In the future, if there's demand, we may see if we can abstract it out cleanly into the platform layer #if APPLE_OSX_mDNSResponder // Even though BTMM client tunnels are only useful for AAAA queries, we need to treat v4 and v6 queries equally. // Otherwise we can get the situation where the A query completes really fast (with an NXDOMAIN result) and the // caller then gives up waiting for the AAAA result while we're still in the process of setting up the tunnel. // To level the playing field, we block both A and AAAA queries while tunnel setup is in progress, and then // returns results for both at the same time. If we are looking for the _autotunnel6 record, then skip this logic // as this would trigger looking up _autotunnel6._autotunnel6 and end up failing the original query. if (RRTypeIsAddressType(question->qtype) && PrivateQuery(question) && !SameDomainLabel(question->qname.c, (const mDNSu8 *)"\x0c_autotunnel6")&& question->QuestionCallback != AutoTunnelCallback) { question->NoAnswer = NoAnswer_Suspended; AddNewClientTunnel(question); return; } #endif // APPLE_OSX_mDNSResponder if (!question->DuplicateOf) { debugf("ActivateUnicastQuery: %##s %s%s%s", question->qname.c, DNSTypeName(question->qtype), PrivateQuery(question) ? " (Private)" : "", ScheduleImmediately ? " ScheduleImmediately" : ""); question->CNAMEReferrals = 0; if (question->nta) { CancelGetZoneData(m, question->nta); question->nta = mDNSNULL; } if (question->LongLived) { question->state = LLQ_InitialRequest; question->id = zeroOpaque64; question->servPort = zeroIPPort; if (question->tcp) { DisposeTCPConn(question->tcp); question->tcp = mDNSNULL; } } // If the question has local answers, then we don't want answers from outside if (ScheduleImmediately && !QuestionHasLocalAnswers(m, question)) { question->ThisQInterval = InitialQuestionInterval; question->LastQTime = m->timenow - question->ThisQInterval; SetNextQueryTime(m, question); } } } // Caller should hold the lock mDNSexport void mDNSCoreRestartAddressQueries(mDNS *const m, mDNSBool SearchDomainsChanged, FlushCache flushCacheRecords, CallbackBeforeStartQuery BeforeStartCallback, void *context) { DNSQuestion *q; DNSQuestion *restart = mDNSNULL; mDNS_CheckLock(m); // 1. Flush the cache records if (flushCacheRecords) flushCacheRecords(m); // 2. Even though we may have purged the cache records above, before it can generate RMV event // we are going to stop the question. Hence we need to deliver the RMV event before we // stop the question. // // CurrentQuestion is used by RmvEventsForQuestion below. While delivering RMV events, the // application callback can potentially stop the current question (detected by CurrentQuestion) or // *any* other question which could be the next one that we may process here. RestartQuestion // points to the "next" question which will be automatically advanced in mDNS_StopQuery_internal // if the "next" question is stopped while the CurrentQuestion is stopped if (m->RestartQuestion) LogMsg("mDNSCoreRestartAddressQueries: ERROR!! m->RestartQuestion already set: %##s (%s)", m->RestartQuestion->qname.c, DNSTypeName(m->RestartQuestion->qtype)); m->RestartQuestion = m->Questions; while (m->RestartQuestion) { q = m->RestartQuestion; m->RestartQuestion = q->next; // GetZoneData questions are referenced by other questions (original query that started the GetZoneData // question) through their "nta" pointer. Normally when the original query stops, it stops the // GetZoneData question and also frees the memory (See CancelGetZoneData). If we stop the GetZoneData // question followed by the original query that refers to this GetZoneData question, we will end up // freeing the GetZoneData question and then start the "freed" question at the end. if (IsGetZoneDataQuestion(q)) { DNSQuestion *refq = q->next; LogInfo("mDNSCoreRestartAddressQueries: Skipping GetZoneDataQuestion %p %##s (%s)", q, q->qname.c, DNSTypeName(q->qtype)); // debug stuff, we just try to find the referencing question and don't do much with it while (refq) { if (q == &refq->nta->question) { LogInfo("mDNSCoreRestartAddressQueries: Question %p %##s (%s) referring to GetZoneDataQuestion %p, not stopping", refq, refq->qname.c, DNSTypeName(refq->qtype), q); } refq = refq->next; } continue; } // This function is called when /etc/hosts changes and that could affect A, AAAA and CNAME queries if (q->qtype != kDNSType_A && q->qtype != kDNSType_AAAA && q->qtype != kDNSType_CNAME) continue; // If the search domains did not change, then we restart all the queries. Otherwise, only // for queries for which we "might" have appended search domains ("might" because we may // find results before we apply search domains even though AppendSearchDomains is set to 1) if (!SearchDomainsChanged || q->AppendSearchDomains) { // NOTE: CacheRecordRmvEventsForQuestion will not generate RMV events for queries that have non-zero // LOAddressAnswers. Hence it is important that we call CacheRecordRmvEventsForQuestion before // LocalRecordRmvEventsForQuestion (which decrements LOAddressAnswers). Let us say that // /etc/hosts has an A Record for web.apple.com. Any queries for web.apple.com will be answered locally. // But this can't prevent a CNAME/AAAA query to not to be sent on the wire. When it is sent on the wire, // it could create cache entries. When we are restarting queries, we can't deliver the cache RMV events // for the original query using these cache entries as ADDs were never delivered using these cache // entries and hence this order is needed. // If the query is suppressed, the RMV events won't be delivered if (!CacheRecordRmvEventsForQuestion(m, q)) { LogInfo("mDNSCoreRestartAddressQueries: Question deleted while delivering Cache Record RMV events"); continue; } // SuppressQuery status does not affect questions that are answered using local records if (!LocalRecordRmvEventsForQuestion(m, q)) { LogInfo("mDNSCoreRestartAddressQueries: Question deleted while delivering Local Record RMV events"); continue; } LogInfo("mDNSCoreRestartAddressQueries: Stop question %p %##s (%s), AppendSearchDomains %d, qnameOrig %p", q, q->qname.c, DNSTypeName(q->qtype), q->AppendSearchDomains, q->qnameOrig); mDNS_StopQuery_internal(m, q); // Reset state so that it looks like it was in the beginning i.e it should look at /etc/hosts, cache // and then search domains should be appended. At the beginning, qnameOrig was NULL. if (q->qnameOrig) { LogInfo("mDNSCoreRestartAddressQueries: qnameOrig %##s", q->qnameOrig); AssignDomainName(&q->qname, q->qnameOrig); mDNSPlatformMemFree(q->qnameOrig); q->qnameOrig = mDNSNULL; q->RetryWithSearchDomains = ApplySearchDomainsFirst(q) ? 1 : 0; } q->SearchListIndex = 0; q->next = restart; restart = q; } } // 3. Callback before we start the query if (BeforeStartCallback) BeforeStartCallback(m, context); // 4. Restart all the stopped queries while (restart) { q = restart; restart = restart->next; q->next = mDNSNULL; LogInfo("mDNSCoreRestartAddressQueries: Start question %p %##s (%s)", q, q->qname.c, DNSTypeName(q->qtype)); mDNS_StartQuery_internal(m, q); } } mDNSexport void mDNSCoreRestartQueries(mDNS *const m) { DNSQuestion *q; #ifndef UNICAST_DISABLED // Retrigger all our uDNS questions if (m->CurrentQuestion) LogMsg("mDNSCoreRestartQueries: ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); m->CurrentQuestion = m->Questions; while (m->CurrentQuestion) { q = m->CurrentQuestion; m->CurrentQuestion = m->CurrentQuestion->next; if (!mDNSOpaque16IsZero(q->TargetQID) && ActiveQuestion(q)) ActivateUnicastQuery(m, q, mDNStrue); } #endif // Retrigger all our mDNS questions for (q = m->Questions; q; q=q->next) // Scan our list of questions mDNSCoreRestartQuestion(m, q); } // restart question if it's multicast and currently active mDNSexport void mDNSCoreRestartQuestion(mDNS *const m, DNSQuestion *q) { if (mDNSOpaque16IsZero(q->TargetQID) && ActiveQuestion(q)) { q->ThisQInterval = InitialQuestionInterval; // MUST be > zero for an active question q->RequestUnicast = kDefaultRequestUnicastCount; q->LastQTime = m->timenow - q->ThisQInterval; q->RecentAnswerPkts = 0; ExpireDupSuppressInfo(q->DupSuppress, m->timenow); m->NextScheduledQuery = m->timenow; } } // restart the probe/announce cycle for multicast record mDNSexport void mDNSCoreRestartRegistration(mDNS *const m, AuthRecord *rr, int announceCount) { if (!AuthRecord_uDNS(rr)) { if (rr->resrec.RecordType == kDNSRecordTypeVerified && !rr->DependentOn) rr->resrec.RecordType = kDNSRecordTypeUnique; rr->ProbeCount = DefaultProbeCountForRecordType(rr->resrec.RecordType); if (mDNS_KeepaliveRecord(&rr->resrec)) { rr->AnnounceCount = 0; // Do not announce keepalive records } else { // announceCount < 0 indicates default announce count should be used if (announceCount < 0) announceCount = InitialAnnounceCount; if (rr->AnnounceCount < (mDNSu8)announceCount) rr->AnnounceCount = (mDNSu8)announceCount; } rr->SendNSECNow = mDNSNULL; InitializeLastAPTime(m, rr); } } // *************************************************************************** #if COMPILER_LIKES_PRAGMA_MARK #pragma mark - #pragma mark - Power Management (Sleep/Wake) #endif mDNSexport void mDNS_UpdateAllowSleep(mDNS *const m) { #ifndef IDLESLEEPCONTROL_DISABLED mDNSBool allowSleep = mDNStrue; char reason[128]; reason[0] = 0; if (m->SystemSleepOnlyIfWakeOnLAN) { // Don't sleep if we are a proxy for any services if (m->ProxyRecords) { allowSleep = mDNSfalse; mDNS_snprintf(reason, sizeof(reason), "sleep proxy for %d records", m->ProxyRecords); LogInfo("mDNS_UpdateAllowSleep: Sleep disabled because we are proxying %d records", m->ProxyRecords); } if (allowSleep && mDNSCoreHaveAdvertisedMulticastServices(m)) { // Scan the list of active interfaces NetworkInterfaceInfo *intf; for (intf = GetFirstActiveInterface(m->HostInterfaces); intf; intf = GetFirstActiveInterface(intf->next)) { if (intf->McastTxRx && !intf->Loopback && !mDNSPlatformInterfaceIsD2D(intf->InterfaceID)) { // Disallow sleep if this interface doesn't support NetWake if (!intf->NetWake) { allowSleep = mDNSfalse; mDNS_snprintf(reason, sizeof(reason), "%s does not support NetWake", intf->ifname); LogInfo("mDNS_UpdateAllowSleep: Sleep disabled because %s does not support NetWake", intf->ifname); break; } // If the interface can be an in-NIC Proxy, we should check if it can accomodate all the records // that will be offloaded. If not, we should prevent sleep. // This check will be possible once the lower layers provide an API to query the space available for offloads on the NIC. #if APPLE_OSX_mDNSResponder if (!SupportsInNICProxy(intf)) #endif { // Disallow sleep if there is no sleep proxy server const CacheRecord *cr = FindSPSInCache1(m, &intf->NetWakeBrowse, mDNSNULL, mDNSNULL); if ( cr == mDNSNULL) { allowSleep = mDNSfalse; mDNS_snprintf(reason, sizeof(reason), "No sleep proxy server on %s", intf->ifname); LogInfo("mDNS_UpdateAllowSleep: Sleep disabled because %s has no sleep proxy server", intf->ifname); break; } else if (m->SPSType != 0) { mDNSu32 mymetric = LocalSPSMetric(m); mDNSu32 metric = SPSMetric(cr->resrec.rdata->u.name.c); if (metric >= mymetric) { allowSleep = mDNSfalse; mDNS_snprintf(reason, sizeof(reason), "No sleep proxy server with better metric on %s", intf->ifname); LogInfo("mDNS_UpdateAllowSleep: Sleep disabled because %s has no sleep proxy server with a better metric", intf->ifname); break; } } } } } } } // Call the platform code to enable/disable sleep mDNSPlatformSetAllowSleep(allowSleep, reason); #else (void) m; #endif /* !defined(IDLESLEEPCONTROL_DISABLED) */ } mDNSlocal mDNSBool mDNSUpdateOkToSend(mDNS *const m, AuthRecord *rr, NetworkInterfaceInfo *const intf, mDNSu32 scopeid) { // If it is not a uDNS record, check to see if the updateid is zero. "updateid" is cleared when we have // sent the resource record on all the interfaces. If the update id is not zero, check to see if it is time // to send. if (AuthRecord_uDNS(rr) || (rr->AuthFlags & AuthFlagsWakeOnly) || mDNSOpaque16IsZero(rr->updateid) || m->timenow - (rr->LastAPTime + rr->ThisAPInterval) < 0) { return mDNSfalse; } // If we have a pending registration for "scopeid", it is ok to send the update on that interface. // If the scopeid is too big to check for validity, we don't check against updateIntID. When // we successfully update on all the interfaces (with whatever set in "rr->updateIntID"), we clear // updateid and we should have returned from above. // // Note: scopeid is the same as intf->InterfaceID. It is passed in so that we don't have to call the // platform function to extract the value from "intf" every time. if ((scopeid >= (sizeof(rr->updateIntID) * mDNSNBBY) || bit_get_opaque64(rr->updateIntID, scopeid)) && (!rr->resrec.InterfaceID || rr->resrec.InterfaceID == intf->InterfaceID)) return mDNStrue; return mDNSfalse; } mDNSexport void UpdateRMAC(mDNS *const m, void *context) { IPAddressMACMapping *addrmap = (IPAddressMACMapping *)context ; m->CurrentRecord = m->ResourceRecords; if (!addrmap) { LogMsg("UpdateRMAC: Address mapping is NULL"); return; } while (m->CurrentRecord) { AuthRecord *rr = m->CurrentRecord; // If this is a non-sleep proxy keepalive record and the remote IP address matches, update the RData if (!rr->WakeUp.HMAC.l[0] && mDNS_KeepaliveRecord(&rr->resrec)) { mDNSAddr raddr; getKeepaliveRaddr(m, rr, &raddr); if (mDNSSameAddress(&raddr, &addrmap->ipaddr)) { // Update the MAC address only if it is not a zero MAC address mDNSEthAddr macAddr; mDNSu8 *ptr = GetValueForMACAddr((mDNSu8 *)(addrmap->ethaddr), (mDNSu8 *) (addrmap->ethaddr + sizeof(addrmap->ethaddr)), &macAddr); if (ptr != mDNSNULL && !mDNSEthAddressIsZero(macAddr)) { UpdateKeepaliveRData(m, rr, mDNSNULL, mDNStrue, (char *)(addrmap->ethaddr)); } } } m->CurrentRecord = rr->next; } if (addrmap) mDNSPlatformMemFree(addrmap); } mDNSexport mStatus UpdateKeepaliveRData(mDNS *const m, AuthRecord *rr, NetworkInterfaceInfo *const intf, mDNSBool updateMac, char *ethAddr) { mDNSu16 newrdlength; mDNSAddr laddr = zeroAddr; mDNSAddr raddr = zeroAddr; mDNSEthAddr eth = zeroEthAddr; mDNSIPPort lport = zeroIPPort; mDNSIPPort rport = zeroIPPort; mDNSu32 timeout = 0; mDNSu32 seq = 0; mDNSu32 ack = 0; mDNSu16 win = 0; UTF8str255 txt; int rdsize; RData *newrd; mDNSTCPInfo mti; mStatus ret; // Note: If we fail to update the DNS NULL record with additional information in this function, it will be registered // with the SPS like any other record. SPS will not send keepalives if it does not have additional information. mDNS_ExtractKeepaliveInfo(rr, &timeout, &laddr, &raddr, ð, &seq, &ack, &lport, &rport, &win); if (!timeout || mDNSAddressIsZero(&laddr) || mDNSAddressIsZero(&raddr) || mDNSIPPortIsZero(lport) || mDNSIPPortIsZero(rport)) { LogMsg("UpdateKeepaliveRData: not a valid record %s for keepalive %#a:%d %#a:%d", ARDisplayString(m, rr), &laddr, lport.NotAnInteger, &raddr, rport.NotAnInteger); return mStatus_UnknownErr; } if (updateMac) { if (laddr.type == mDNSAddrType_IPv4) newrdlength = mDNS_snprintf((char *)&txt.c[1], sizeof(txt.c) - 1, "t=%d i=%d c=%d h=%#a d=%#a l=%u r=%u m=%s", timeout, kKeepaliveRetryInterval, kKeepaliveRetryCount, &laddr, &raddr, mDNSVal16(lport), mDNSVal16(rport), ethAddr); else newrdlength = mDNS_snprintf((char *)&txt.c[1], sizeof(txt.c) - 1, "t=%d i=%d c=%d H=%#a D=%#a l=%u r=%u m=%s", timeout, kKeepaliveRetryInterval, kKeepaliveRetryCount, &laddr, &raddr, mDNSVal16(lport), mDNSVal16(rport), ethAddr); } else { // If this keepalive packet would be sent on a different interface than the current one that we are processing // now, then we don't update the DNS NULL record. But we do not prevent it from registering with the SPS. When SPS sees // this DNS NULL record, it does not send any keepalives as it does not have all the information mDNSPlatformMemZero(&mti, sizeof (mDNSTCPInfo)); ret = mDNSPlatformRetrieveTCPInfo(&laddr, &lport, &raddr, &rport, &mti); if (ret != mStatus_NoError) { LogMsg("mDNSPlatformRetrieveTCPInfo: mDNSPlatformRetrieveTCPInfo failed %d", ret); return ret; } if ((intf != mDNSNULL) && (mti.IntfId != intf->InterfaceID)) { LogInfo("mDNSPlatformRetrieveTCPInfo: InterfaceID mismatch mti.IntfId = %p InterfaceID = %p", mti.IntfId, intf->InterfaceID); return mStatus_BadParamErr; } if (laddr.type == mDNSAddrType_IPv4) newrdlength = mDNS_snprintf((char *)&txt.c[1], sizeof(txt.c) - 1, "t=%d i=%d c=%d h=%#a d=%#a l=%u r=%u m=%.6a s=%u a=%u w=%u", timeout, kKeepaliveRetryInterval, kKeepaliveRetryCount, &laddr, &raddr, mDNSVal16(lport), mDNSVal16(rport), ð, mti.seq, mti.ack, mti.window); else newrdlength = mDNS_snprintf((char *)&txt.c[1], sizeof(txt.c) - 1, "t=%d i=%d c=%d H=%#a D=%#a l=%u r=%u m=%.6a s=%u a=%u w=%u", timeout, kKeepaliveRetryInterval, kKeepaliveRetryCount, &laddr, &raddr, mDNSVal16(lport), mDNSVal16(rport), ð, mti.seq, mti.ack, mti.window); } // Did we insert a null byte at the end ? if (newrdlength == (sizeof(txt.c) - 1)) { LogMsg("UpdateKeepaliveRData: could not allocate memory %s", ARDisplayString(m, rr)); return mStatus_NoMemoryErr; } // Include the length for the null byte at the end txt.c[0] = newrdlength + 1; // Account for the first length byte and the null byte at the end newrdlength += 2; rdsize = newrdlength > sizeof(RDataBody) ? newrdlength : sizeof(RDataBody); newrd = mDNSPlatformMemAllocate(sizeof(RData) - sizeof(RDataBody) + rdsize); if (!newrd) { LogMsg("UpdateKeepaliveRData: ptr NULL"); return mStatus_NoMemoryErr; } newrd->MaxRDLength = (mDNSu16) rdsize; mDNSPlatformMemCopy(&newrd->u, txt.c, newrdlength); // If we are updating the record for the first time, rdata points to rdatastorage as the rdata memory // was allocated as part of the AuthRecord itself. We allocate memory when we update the AuthRecord. // If the resource record has data that we allocated in a previous pass (to update MAC address), // free that memory here before copying in the new data. if ( rr->resrec.rdata != &rr->rdatastorage) { LogSPS("UpdateKeepaliveRData: Freed allocated memory for keep alive packet: %s ", ARDisplayString(m, rr)); mDNSPlatformMemFree(rr->resrec.rdata); } SetNewRData(&rr->resrec, newrd, newrdlength); // Update our rdata LogSPS("UpdateKeepaliveRData: successfully updated the record %s", ARDisplayString(m, rr)); return mStatus_NoError; } mDNSlocal void SendSPSRegistrationForOwner(mDNS *const m, NetworkInterfaceInfo *const intf, const mDNSOpaque16 id, const OwnerOptData *const owner) { const int optspace = DNSOpt_Header_Space + DNSOpt_LeaseData_Space + DNSOpt_Owner_Space(&m->PrimaryMAC, &intf->MAC); const int sps = intf->NextSPSAttempt / 3; AuthRecord *rr; mDNSOpaque16 msgid; mDNSu32 scopeid; scopeid = mDNSPlatformInterfaceIndexfromInterfaceID(m, intf->InterfaceID, mDNStrue); if (!intf->SPSAddr[sps].type) { intf->NextSPSAttemptTime = m->timenow + mDNSPlatformOneSecond; if (m->NextScheduledSPRetry - intf->NextSPSAttemptTime > 0) m->NextScheduledSPRetry = intf->NextSPSAttemptTime; LogSPS("SendSPSRegistration: %s SPS %d (%d) %##s not yet resolved", intf->ifname, intf->NextSPSAttempt, sps, intf->NetWakeResolve[sps].qname.c); goto exit; } // Mark our mDNS records (not unicast records) for transfer to SPS if (mDNSOpaque16IsZero(id)) { // We may have to register this record over multiple interfaces and we don't want to // overwrite the id. We send the registration over interface X with id "IDX" and before // we get a response, we overwrite with id "IDY" for interface Y and we won't accept responses // for "IDX". Hence, we want to use the same ID across all interfaces. // // In the case of sleep proxy server transfering its records when it goes to sleep, the owner // option check below will set the same ID across the records from the same owner. Records // with different owner option gets different ID. msgid = mDNS_NewMessageID(m); for (rr = m->ResourceRecords; rr; rr=rr->next) { if (!(rr->AuthFlags & AuthFlagsWakeOnly) && rr->resrec.RecordType > kDNSRecordTypeDeregistering) { if (rr->resrec.InterfaceID == intf->InterfaceID || (!rr->resrec.InterfaceID && (rr->ForceMCast || IsLocalDomain(rr->resrec.name)))) { if (mDNSPlatformMemSame(owner, &rr->WakeUp, sizeof(*owner))) { rr->SendRNow = mDNSInterfaceMark; // mark it now // When we are registering on the first interface, rr->updateid is zero in which case // initialize with the new ID. For subsequent interfaces, we want to use the same ID. // At the end, all the updates sent across all the interfaces with the same ID. if (mDNSOpaque16IsZero(rr->updateid)) rr->updateid = msgid; else msgid = rr->updateid; } } } } } else msgid = id; while (1) { mDNSu8 *p = m->omsg.data; // To comply with RFC 2782, PutResourceRecord suppresses name compression for SRV records in unicast updates. // For now we follow that same logic for SPS registrations too. // If we decide to compress SRV records in SPS registrations in the future, we can achieve that by creating our // initial DNSMessage with h.flags set to zero, and then update it to UpdateReqFlags right before sending the packet. InitializeDNSMessage(&m->omsg.h, msgid, UpdateReqFlags); for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->SendRNow || mDNSUpdateOkToSend(m, rr, intf, scopeid)) { if (mDNSPlatformMemSame(owner, &rr->WakeUp, sizeof(*owner))) { mDNSu8 *newptr; const mDNSu8 *const limit = m->omsg.data + (m->omsg.h.mDNS_numUpdates ? NormalMaxDNSMessageData : AbsoluteMaxDNSMessageData) - optspace; // If we can't update the keepalive record, don't send it if (mDNS_KeepaliveRecord(&rr->resrec) && (UpdateKeepaliveRData(m, rr, intf, mDNSfalse, mDNSNULL) != mStatus_NoError)) { if (scopeid < (sizeof(rr->updateIntID) * mDNSNBBY)) { bit_clr_opaque64(rr->updateIntID, scopeid); } rr->SendRNow = mDNSNULL; continue; } if (rr->resrec.RecordType & kDNSRecordTypeUniqueMask) rr->resrec.rrclass |= kDNSClass_UniqueRRSet; // Temporarily set the 'unique' bit so PutResourceRecord will set it newptr = PutResourceRecordTTLWithLimit(&m->omsg, p, &m->omsg.h.mDNS_numUpdates, &rr->resrec, rr->resrec.rroriginalttl, limit); rr->resrec.rrclass &= ~kDNSClass_UniqueRRSet; // Make sure to clear 'unique' bit back to normal state if (!newptr) LogSPS("SendSPSRegistration put %s FAILED %d/%d %s", intf->ifname, p - m->omsg.data, limit - m->omsg.data, ARDisplayString(m, rr)); else { LogSPS("SendSPSRegistration put %s 0x%x 0x%x (updateid %d) %s", intf->ifname, rr->updateIntID.l[1], rr->updateIntID.l[0], mDNSVal16(m->omsg.h.id), ARDisplayString(m, rr)); rr->SendRNow = mDNSNULL; rr->ThisAPInterval = mDNSPlatformOneSecond; rr->LastAPTime = m->timenow; // should be initialized above if (mDNSOpaque16IsZero(rr->updateid)) LogMsg("SendSPSRegistration: ERROR!! rr %s updateid is zero", ARDisplayString(m, rr)); if (m->NextScheduledResponse - (rr->LastAPTime + rr->ThisAPInterval) >= 0) m->NextScheduledResponse = (rr->LastAPTime + rr->ThisAPInterval); p = newptr; } } } if (!m->omsg.h.mDNS_numUpdates) break; else { AuthRecord opt; mDNS_SetupResourceRecord(&opt, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); opt.resrec.rrclass = NormalMaxDNSMessageData; opt.resrec.rdlength = sizeof(rdataOPT) * 2; // Two options in this OPT record opt.resrec.rdestimate = sizeof(rdataOPT) * 2; opt.resrec.rdata->u.opt[0].opt = kDNSOpt_Lease; opt.resrec.rdata->u.opt[0].optlen = DNSOpt_LeaseData_Space - 4; opt.resrec.rdata->u.opt[0].u.updatelease = DEFAULT_UPDATE_LEASE; if (!owner->HMAC.l[0]) // If no owner data, SetupOwnerOpt(m, intf, &opt.resrec.rdata->u.opt[1]); // use our own interface information else // otherwise, use the owner data we were given { opt.resrec.rdata->u.opt[1].u.owner = *owner; opt.resrec.rdata->u.opt[1].opt = kDNSOpt_Owner; opt.resrec.rdata->u.opt[1].optlen = DNSOpt_Owner_Space(&owner->HMAC, &owner->IMAC) - 4; } LogSPS("SendSPSRegistration put %s %s", intf->ifname, ARDisplayString(m, &opt)); p = PutResourceRecordTTLWithLimit(&m->omsg, p, &m->omsg.h.numAdditionals, &opt.resrec, opt.resrec.rroriginalttl, m->omsg.data + AbsoluteMaxDNSMessageData); if (!p) LogMsg("SendSPSRegistration: Failed to put OPT record (%d updates) %s", m->omsg.h.mDNS_numUpdates, ARDisplayString(m, &opt)); else { mStatus err; LogSPS("SendSPSRegistration: Sending Update %s %d (%d) id %5d with %d records %d bytes to %#a:%d", intf->ifname, intf->NextSPSAttempt, sps, mDNSVal16(m->omsg.h.id), m->omsg.h.mDNS_numUpdates, p - m->omsg.data, &intf->SPSAddr[sps], mDNSVal16(intf->SPSPort[sps])); // if (intf->NextSPSAttempt < 5) m->omsg.h.flags = zeroID; // For simulating packet loss err = mDNSSendDNSMessage(m, &m->omsg, p, intf->InterfaceID, mDNSNULL, &intf->SPSAddr[sps], intf->SPSPort[sps], mDNSNULL, mDNSNULL, mDNSfalse); if (err) LogSPS("SendSPSRegistration: mDNSSendDNSMessage err %d", err); if (err && intf->SPSAddr[sps].type == mDNSAddrType_IPv4 && intf->NetWakeResolve[sps].ThisQInterval == -1) { LogSPS("SendSPSRegistration %d %##s failed to send to IPv4 address; will try IPv6 instead", sps, intf->NetWakeResolve[sps].qname.c); intf->NetWakeResolve[sps].qtype = kDNSType_AAAA; mDNS_StartQuery_internal(m, &intf->NetWakeResolve[sps]); return; } } } } intf->NextSPSAttemptTime = m->timenow + mDNSPlatformOneSecond * 10; // If successful, update NextSPSAttemptTime exit: if (mDNSOpaque16IsZero(id) && intf->NextSPSAttempt < 8) intf->NextSPSAttempt++; } mDNSlocal mDNSBool RecordIsFirstOccurrenceOfOwner(mDNS *const m, const AuthRecord *const rr) { AuthRecord *ar; for (ar = m->ResourceRecords; ar && ar != rr; ar=ar->next) if (mDNSPlatformMemSame(&rr->WakeUp, &ar->WakeUp, sizeof(rr->WakeUp))) return mDNSfalse; return mDNStrue; } mDNSlocal void mDNSCoreStoreProxyRR(mDNS *const m, const mDNSInterfaceID InterfaceID, AuthRecord *const rr) { AuthRecord *newRR = mDNSPlatformMemAllocate(sizeof(AuthRecord)); if (newRR == mDNSNULL) { LogSPS("%s : could not allocate memory for new resource record", __func__); return; } mDNSPlatformMemZero(newRR, sizeof(AuthRecord)); mDNS_SetupResourceRecord(newRR, mDNSNULL, InterfaceID, rr->resrec.rrtype, rr->resrec.rroriginalttl, rr->resrec.RecordType, rr->ARType, mDNSNULL, mDNSNULL); AssignDomainName(&newRR->namestorage, &rr->namestorage); newRR->resrec.rdlength = DomainNameLength(rr->resrec.name); newRR->resrec.namehash = DomainNameHashValue(newRR->resrec.name); newRR->resrec.rrclass = rr->resrec.rrclass; if (rr->resrec.rrtype == kDNSType_A) { newRR->resrec.rdata->u.ipv4 = rr->resrec.rdata->u.ipv4; } else if (rr->resrec.rrtype == kDNSType_AAAA) { newRR->resrec.rdata->u.ipv6 = rr->resrec.rdata->u.ipv6; } SetNewRData(&newRR->resrec, mDNSNULL, 0); // Insert the new node at the head of the list. newRR->next = m->SPSRRSet; m->SPSRRSet = newRR; LogSPS("%s : Storing proxy record : %s ", __func__, ARDisplayString(m, rr)); } // Some records are interface specific and some are not. The ones that are supposed to be registered // on multiple interfaces need to be initialized with all the valid interfaces on which it will be sent. // updateIntID bit field tells us on which interfaces we need to register this record. When we get an // ack from the sleep proxy server, we clear the interface bit. This way, we know when a record completes // registration on all the interfaces mDNSlocal void SPSInitRecordsBeforeUpdate(mDNS *const m, mDNSOpaque64 updateIntID, mDNSBool *WakeOnlyService) { AuthRecord *ar; LogSPS("SPSInitRecordsBeforeUpdate: UpdateIntID 0x%x 0x%x", updateIntID.l[1], updateIntID.l[0]); *WakeOnlyService = mDNSfalse; // Before we store the A and AAAA records that we are going to register with the sleep proxy, // make sure that the old sleep proxy records are removed. mDNSCoreFreeProxyRR(m); // For records that are registered only on a specific interface, mark only that bit as it will // never be registered on any other interface. For others, it should be sent on all interfaces. for (ar = m->ResourceRecords; ar; ar=ar->next) { ar->updateIntID = zeroOpaque64; ar->updateid = zeroID; if (AuthRecord_uDNS(ar)) { continue; } if (ar->AuthFlags & AuthFlagsWakeOnly) { if (ar->resrec.RecordType == kDNSRecordTypeShared && ar->RequireGoodbye) { ar->ImmedAnswer = mDNSInterfaceMark; *WakeOnlyService = mDNStrue; continue; } } if (!ar->resrec.InterfaceID) { LogSPS("Setting scopeid (ALL) 0x%x 0x%x for %s", updateIntID.l[1], updateIntID.l[0], ARDisplayString(m, ar)); ar->updateIntID = updateIntID; } else { // Filter records that belong to interfaces that we won't register the records on. UpdateIntID captures // exactly this. mDNSu32 scopeid = mDNSPlatformInterfaceIndexfromInterfaceID(m, ar->resrec.InterfaceID, mDNStrue); if ((scopeid < (sizeof(updateIntID) * mDNSNBBY)) && bit_get_opaque64(updateIntID, scopeid)) { bit_set_opaque64(ar->updateIntID, scopeid); LogSPS("SPSInitRecordsBeforeUpdate: Setting scopeid(%d) 0x%x 0x%x for %s", scopeid, ar->updateIntID.l[1], ar->updateIntID.l[0], ARDisplayString(m, ar)); } else { LogSPS("SPSInitRecordsBeforeUpdate: scopeid %d beyond range or not valid for SPS registration", scopeid); } } // Store the A and AAAA records that we registered with the sleep proxy. // We will use this to prevent spurious name conflicts that may occur when we wake up if (ar->resrec.rrtype == kDNSType_A || ar->resrec.rrtype == kDNSType_AAAA) { mDNSCoreStoreProxyRR(m, ar->resrec.InterfaceID, ar); } } } mDNSlocal void SendSPSRegistration(mDNS *const m, NetworkInterfaceInfo *const intf, const mDNSOpaque16 id) { AuthRecord *ar; OwnerOptData owner = zeroOwner; SendSPSRegistrationForOwner(m, intf, id, &owner); for (ar = m->ResourceRecords; ar; ar=ar->next) { if (!mDNSPlatformMemSame(&owner, &ar->WakeUp, sizeof(owner)) && RecordIsFirstOccurrenceOfOwner(m, ar)) { owner = ar->WakeUp; SendSPSRegistrationForOwner(m, intf, id, &owner); } } } // RetrySPSRegistrations is called from SendResponses, with the lock held mDNSlocal void RetrySPSRegistrations(mDNS *const m) { AuthRecord *rr; NetworkInterfaceInfo *intf; // First make sure none of our interfaces' NextSPSAttemptTimes are inadvertently set to m->timenow + mDNSPlatformOneSecond * 10 for (intf = GetFirstActiveInterface(m->HostInterfaces); intf; intf = GetFirstActiveInterface(intf->next)) if (intf->NextSPSAttempt && intf->NextSPSAttemptTime == m->timenow + mDNSPlatformOneSecond * 10) intf->NextSPSAttemptTime++; // Retry any record registrations that are due for (rr = m->ResourceRecords; rr; rr=rr->next) if (!AuthRecord_uDNS(rr) && !mDNSOpaque16IsZero(rr->updateid) && m->timenow - (rr->LastAPTime + rr->ThisAPInterval) >= 0) { for (intf = GetFirstActiveInterface(m->HostInterfaces); intf; intf = GetFirstActiveInterface(intf->next)) { // If we still have registrations pending on this interface, send it now mDNSu32 scopeid = mDNSPlatformInterfaceIndexfromInterfaceID(m, intf->InterfaceID, mDNStrue); if ((scopeid >= (sizeof(rr->updateIntID) * mDNSNBBY) || bit_get_opaque64(rr->updateIntID, scopeid)) && (!rr->resrec.InterfaceID || rr->resrec.InterfaceID == intf->InterfaceID)) { LogSPS("RetrySPSRegistrations: 0x%x 0x%x (updateid %d) %s", rr->updateIntID.l[1], rr->updateIntID.l[0], mDNSVal16(rr->updateid), ARDisplayString(m, rr)); SendSPSRegistration(m, intf, rr->updateid); } } } // For interfaces where we did an SPS registration attempt, increment intf->NextSPSAttempt for (intf = GetFirstActiveInterface(m->HostInterfaces); intf; intf = GetFirstActiveInterface(intf->next)) if (intf->NextSPSAttempt && intf->NextSPSAttemptTime == m->timenow + mDNSPlatformOneSecond * 10 && intf->NextSPSAttempt < 8) intf->NextSPSAttempt++; } mDNSlocal void NetWakeResolve(mDNS *const m, DNSQuestion *question, const ResourceRecord *const answer, QC_result AddRecord) { NetworkInterfaceInfo *intf = (NetworkInterfaceInfo *)question->QuestionContext; int sps = (int)(question - intf->NetWakeResolve); (void)m; // Unused LogSPS("NetWakeResolve: SPS: %d Add: %d %s", sps, AddRecord, RRDisplayString(m, answer)); if (!AddRecord) return; // Don't care about REMOVE events if (answer->rrtype != question->qtype) return; // Don't care about CNAMEs // if (answer->rrtype == kDNSType_AAAA && sps == 0) return; // To test failing to resolve sleep proxy's address if (answer->rrtype == kDNSType_SRV) { // 1. Got the SRV record; now look up the target host's IP address mDNS_StopQuery(m, question); intf->SPSPort[sps] = answer->rdata->u.srv.port; AssignDomainName(&question->qname, &answer->rdata->u.srv.target); question->qtype = kDNSType_A; mDNS_StartQuery(m, question); } else if (answer->rrtype == kDNSType_A && answer->rdlength == sizeof(mDNSv4Addr)) { // 2. Got an IPv4 address for the target host; record address and initiate an SPS registration if appropriate mDNS_StopQuery(m, question); question->ThisQInterval = -1; intf->SPSAddr[sps].type = mDNSAddrType_IPv4; intf->SPSAddr[sps].ip.v4 = answer->rdata->u.ipv4; mDNS_Lock(m); if (sps == intf->NextSPSAttempt/3) SendSPSRegistration(m, intf, zeroID); // If we're ready for this result, use it now mDNS_Unlock(m); } else if (answer->rrtype == kDNSType_A && answer->rdlength == 0) { // 3. Got negative response -- target host apparently has IPv6 disabled -- so try looking up the target host's IPv4 address(es) instead mDNS_StopQuery(m, question); LogSPS("NetWakeResolve: SPS %d %##s has no IPv4 address, will try IPv6 instead", sps, question->qname.c); question->qtype = kDNSType_AAAA; mDNS_StartQuery(m, question); } else if (answer->rrtype == kDNSType_AAAA && answer->rdlength == sizeof(mDNSv6Addr) && mDNSv6AddressIsLinkLocal(&answer->rdata->u.ipv6)) { // 4. Got the target host's IPv6 link-local address; record address and initiate an SPS registration if appropriate mDNS_StopQuery(m, question); question->ThisQInterval = -1; intf->SPSAddr[sps].type = mDNSAddrType_IPv6; intf->SPSAddr[sps].ip.v6 = answer->rdata->u.ipv6; mDNS_Lock(m); if (sps == intf->NextSPSAttempt/3) SendSPSRegistration(m, intf, zeroID); // If we're ready for this result, use it now mDNS_Unlock(m); } } mDNSexport mDNSBool mDNSCoreHaveAdvertisedMulticastServices(mDNS *const m) { AuthRecord *rr; for (rr = m->ResourceRecords; rr; rr=rr->next) if (mDNS_KeepaliveRecord(&rr->resrec) || (rr->resrec.rrtype == kDNSType_SRV && !AuthRecord_uDNS(rr) && !mDNSSameIPPort(rr->resrec.rdata->u.srv.port, DiscardPort))) return mDNStrue; return mDNSfalse; } #define WAKE_ONLY_SERVICE 1 #define AC_ONLY_SERVICE 2 #ifdef APPLE_OSX_mDNSResponder mDNSlocal void SendGoodbyesForSelectServices(mDNS *const m, mDNSBool *servicePresent, mDNSu32 serviceType) { AuthRecord *rr; *servicePresent = mDNSfalse; // Mark all the records we need to deregister and send them for (rr = m->ResourceRecords; rr; rr=rr->next) { // If the service type is wake only service and the auth flags match and requires a goodbye // OR if the service type is AC only and it is not a keepalive record, // mark the records we need to deregister and send them if ((serviceType == WAKE_ONLY_SERVICE && (rr->AuthFlags & AuthFlagsWakeOnly) && rr->resrec.RecordType == kDNSRecordTypeShared && rr->RequireGoodbye) || (serviceType == AC_ONLY_SERVICE && !mDNS_KeepaliveRecord(&rr->resrec))) { rr->ImmedAnswer = mDNSInterfaceMark; *servicePresent = mDNStrue; } } } #endif #ifdef APPLE_OSX_mDNSResponder // This function is used only in the case of local NIC proxy. For external // sleep proxy server, we do this in SPSInitRecordsBeforeUpdate when we // walk the resource records. mDNSlocal void SendGoodbyesForWakeOnlyService(mDNS *const m, mDNSBool *WakeOnlyService) { return SendGoodbyesForSelectServices(m, WakeOnlyService, WAKE_ONLY_SERVICE); } #endif // APPLE_OSX_mDNSResponder mDNSlocal void SendSleepGoodbyes(mDNS *const m, mDNSBool AllInterfaces, mDNSBool unicast) { AuthRecord *rr; m->SleepState = SleepState_Sleeping; // If AllInterfaces is not set, the caller has already marked it appropriately // on which interfaces this should be sent. if (AllInterfaces) { NetworkInterfaceInfo *intf; for (intf = GetFirstActiveInterface(m->HostInterfaces); intf; intf = GetFirstActiveInterface(intf->next)) { intf->SendGoodbyes = 1; } } if (unicast) { #ifndef UNICAST_DISABLED SleepRecordRegistrations(m); // If we have no SPS, need to deregister our uDNS records #endif /* UNICAST_DISABLED */ } // Mark all the records we need to deregister and send them for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->resrec.RecordType == kDNSRecordTypeShared && rr->RequireGoodbye) rr->ImmedAnswer = mDNSInterfaceMark; SendResponses(m); } /* * This function attempts to detect if multiple interfaces are on the same subnet. * It makes this determination based only on the IPv4 Addresses and subnet masks. * IPv6 link local addresses that are configured by default on all interfaces make * it hard to make this determination * * The 'real' fix for this would be to send out multicast packets over one interface * and conclude that multiple interfaces are on the same subnet only if these packets * are seen on other interfaces on the same system */ mDNSlocal mDNSBool skipSameSubnetRegistration(mDNS *const m, mDNSInterfaceID *regID, mDNSu32 count, mDNSInterfaceID intfid) { NetworkInterfaceInfo *intf; NetworkInterfaceInfo *newIntf; mDNSu32 i; for (newIntf = FirstInterfaceForID(m, intfid); newIntf; newIntf = newIntf->next) { if ((newIntf->InterfaceID != intfid) || (newIntf->ip.type != mDNSAddrType_IPv4)) { continue; } for ( i = 0; i < count; i++) { for (intf = FirstInterfaceForID(m, regID[i]); intf; intf = intf->next) { if ((intf->InterfaceID != regID[i]) || (intf->ip.type != mDNSAddrType_IPv4)) { continue; } if ((intf->ip.ip.v4.NotAnInteger & intf->mask.ip.v4.NotAnInteger) == (newIntf->ip.ip.v4.NotAnInteger & newIntf->mask.ip.v4.NotAnInteger)) { LogSPS("%s : Already registered for the same subnet (IPv4) for interface %s", __func__, intf->ifname); return (mDNStrue); } } } } return (mDNSfalse); } mDNSlocal void DoKeepaliveCallbacks(mDNS *m) { // Loop through the keepalive records and callback with an error m->CurrentRecord = m->ResourceRecords; while (m->CurrentRecord) { AuthRecord *const rr = m->CurrentRecord; if ((mDNS_KeepaliveRecord(&rr->resrec)) && (rr->resrec.RecordType != kDNSRecordTypeDeregistering)) { LogSPS("DoKeepaliveCallbacks: Invoking the callback for %s", ARDisplayString(m, rr)); if (rr->RecordCallback) rr->RecordCallback(m, rr, mStatus_BadStateErr); } if (m->CurrentRecord == rr) // If m->CurrentRecord was not advanced for us, do it now m->CurrentRecord = rr->next; } } // BeginSleepProcessing is called, with the lock held, from either mDNS_Execute or mDNSCoreMachineSleep mDNSlocal void BeginSleepProcessing(mDNS *const m) { mDNSBool SendGoodbyes = mDNStrue; mDNSBool WakeOnlyService = mDNSfalse; mDNSBool invokeKACallback = mDNStrue; const CacheRecord *sps[3] = { mDNSNULL }; mDNSOpaque64 updateIntID = zeroOpaque64; mDNSInterfaceID registeredIntfIDS[128] = { 0 }; mDNSu32 registeredCount = 0; int skippedRegistrations = 0; m->NextScheduledSPRetry = m->timenow; // Clear out the SCDynamic entry that stores the external SPS information mDNSPlatformClearSPSData(); if (!m->SystemWakeOnLANEnabled) LogSPS("BeginSleepProcessing: m->SystemWakeOnLANEnabled is false"); else if (!mDNSCoreHaveAdvertisedMulticastServices(m)) LogSPS("BeginSleepProcessing: No advertised services"); else // If we have at least one advertised service { NetworkInterfaceInfo *intf; for (intf = GetFirstActiveInterface(m->HostInterfaces); intf; intf = GetFirstActiveInterface(intf->next)) { // Intialize it to false. These values make sense only when SleepState is set to Sleeping. intf->SendGoodbyes = 0; // If it is not multicast capable, we could not have possibly discovered sleep proxy // servers. if (!intf->McastTxRx || mDNSPlatformInterfaceIsD2D(intf->InterfaceID)) { LogSPS("BeginSleepProcessing: %-6s Ignoring for registrations", intf->ifname); continue; } // If we are not capable of WOMP, then don't register with sleep proxy. // // Note: If we are not NetWake capable, we don't browse for the sleep proxy server. // We might find sleep proxy servers in the cache and start a resolve on them. // But then if the interface goes away, we won't stop these questions because // mDNS_DeactivateNetWake_internal assumes that a browse has been started for it // to stop both the browse and resolve questions. if (!intf->NetWake) { LogSPS("BeginSleepProcessing: %-6s not capable of magic packet wakeup", intf->ifname); intf->SendGoodbyes = 1; skippedRegistrations++; continue; } // Check if we have already registered with a sleep proxy for this subnet if (skipSameSubnetRegistration(m, registeredIntfIDS, registeredCount, intf->InterfaceID)) { LogSPS("%s : Skipping sleep proxy registration on %s", __func__, intf->ifname); continue; } #if APPLE_OSX_mDNSResponder else if (SupportsInNICProxy(intf)) { mDNSBool keepaliveOnly = mDNSfalse; if (ActivateLocalProxy(intf, &keepaliveOnly) == mStatus_NoError) { SendGoodbyesForWakeOnlyService(m, &WakeOnlyService); // Send goodbyes for all advertised services if the only record offloaded was the keepalive record. SendGoodbyes = (keepaliveOnly) ? mDNStrue: mDNSfalse; invokeKACallback = mDNSfalse; LogSPS("BeginSleepProcessing: %-6s using local proxy", intf->ifname); // This will leave m->SleepState set to SleepState_Transferring, // which is okay because with no outstanding resolves, or updates in flight, // mDNSCoreReadyForSleep() will conclude correctly that all the updates have already completed // Setting this flag activates the SleepLimit which delays sleep by 5 seconds and // will allow the system to deregister any BTMM records. m->NextScheduledSPRetry = m->timenow + (5 * mDNSPlatformOneSecond); registeredIntfIDS[registeredCount] = intf->InterfaceID; registeredCount++; } } #endif // APPLE_OSX_mDNSResponder else { #if APPLE_OSX_mDNSResponder // If on battery, do not attempt to offload to external sleep proxies if (m->SystemWakeOnLANEnabled == mDNS_WakeOnBattery) { LogSPS("BegingSleepProcessing: Not connected to AC power - Not registering with an external sleep proxy."); return; } #endif // APPLE_OSX_mDNSResponder FindSPSInCache(m, &intf->NetWakeBrowse, sps); if (!sps[0]) LogSPS("BeginSleepProcessing: %-6s %#a No Sleep Proxy Server found (Next Browse Q in %d, interval %d)", intf->ifname, &intf->ip, NextQSendTime(&intf->NetWakeBrowse) - m->timenow, intf->NetWakeBrowse.ThisQInterval); else { int i; mDNSu32 scopeid; SendGoodbyes = mDNSfalse; intf->NextSPSAttempt = 0; intf->NextSPSAttemptTime = m->timenow + mDNSPlatformOneSecond; scopeid = mDNSPlatformInterfaceIndexfromInterfaceID(m, intf->InterfaceID, mDNStrue); // Now we know for sure that we have to wait for registration to complete on this interface. if (scopeid < (sizeof(updateIntID) * mDNSNBBY)) bit_set_opaque64(updateIntID, scopeid); // Don't need to set m->NextScheduledSPRetry here because we already set "m->NextScheduledSPRetry = m->timenow" above for (i=0; i<3; i++) { #if ForceAlerts if (intf->SPSAddr[i].type) LogFatalError("BeginSleepProcessing: %s %d intf->SPSAddr[i].type %d", intf->ifname, i, intf->SPSAddr[i].type); if (intf->NetWakeResolve[i].ThisQInterval >= 0) LogFatalError("BeginSleepProcessing: %s %d intf->NetWakeResolve[i].ThisQInterval %d", intf->ifname, i, intf->NetWakeResolve[i].ThisQInterval); #endif intf->SPSAddr[i].type = mDNSAddrType_None; if (intf->NetWakeResolve[i].ThisQInterval >= 0) mDNS_StopQuery(m, &intf->NetWakeResolve[i]); intf->NetWakeResolve[i].ThisQInterval = -1; if (sps[i]) { LogSPS("BeginSleepProcessing: %-6s Found Sleep Proxy Server %d TTL %d %s", intf->ifname, i, sps[i]->resrec.rroriginalttl, CRDisplayString(m, sps[i])); mDNS_SetupQuestion(&intf->NetWakeResolve[i], intf->InterfaceID, &sps[i]->resrec.rdata->u.name, kDNSType_SRV, NetWakeResolve, intf); intf->NetWakeResolve[i].ReturnIntermed = mDNStrue; mDNS_StartQuery_internal(m, &intf->NetWakeResolve[i]); // If we are registering with a Sleep Proxy for a new subnet, add it to our list registeredIntfIDS[registeredCount] = intf->InterfaceID; registeredCount++; } } } } } } // If we have at least one interface on which we are registering with an external sleep proxy, // initialize all the records appropriately. if (!mDNSOpaque64IsZero(&updateIntID)) SPSInitRecordsBeforeUpdate(m, updateIntID, &WakeOnlyService); // Call the applicaitons that registered a keepalive record to inform them that we failed to offload // the records to a sleep proxy. if (invokeKACallback) { LogSPS("BeginSleepProcessing: Did not register with an in-NIC proxy - invoking the callbacks for KA records"); DoKeepaliveCallbacks(m); } // SendSleepGoodbyes last two arguments control whether we send goodbyes on all // interfaces and also deregister unicast registrations. // // - If there are no sleep proxy servers, then send goodbyes on all interfaces // for both multicast and unicast. // // - If we skipped registrations on some interfaces, then we have already marked // them appropriately above. We don't need to send goodbyes for unicast as // we have registered with at least one sleep proxy. // // - If we are not planning to send any goodbyes, then check for WakeOnlyServices. // // Note: If we are planning to send goodbyes, we mark the record with mDNSInterfaceAny // and call SendResponses which inturn calls ShouldSendGoodbyesBeforeSleep which looks // at WakeOnlyServices first. if (SendGoodbyes) { LogSPS("BeginSleepProcessing: Not registering with Sleep Proxy Server"); SendSleepGoodbyes(m, mDNStrue, mDNStrue); } else if (skippedRegistrations) { LogSPS("BeginSleepProcessing: Not registering with Sleep Proxy Server on all interfaces"); SendSleepGoodbyes(m, mDNSfalse, mDNSfalse); } else if (WakeOnlyService) { // If we saw WakeOnly service above, send the goodbyes now. LogSPS("BeginSleepProcessing: Sending goodbyes for WakeOnlyService"); SendResponses(m); } } // Call mDNSCoreMachineSleep(m, mDNStrue) when the machine is about to go to sleep. // Call mDNSCoreMachineSleep(m, mDNSfalse) when the machine is has just woken up. // Normally, the platform support layer below mDNSCore should call this, not the client layer above. mDNSexport void mDNSCoreMachineSleep(mDNS *const m, mDNSBool sleep) { AuthRecord *rr; LogSPS("%s (old state %d) at %ld", sleep ? "Sleeping" : "Waking", m->SleepState, m->timenow); if (sleep && !m->SleepState) // Going to sleep { mDNS_Lock(m); // If we're going to sleep, need to stop advertising that we're a Sleep Proxy Server if (m->SPSSocket) { mDNSu8 oldstate = m->SPSState; mDNS_DropLockBeforeCallback(); // mDNS_DeregisterService expects to be called without the lock held, so we emulate that here m->SPSState = 2; #ifndef SPC_DISABLED if (oldstate == 1) mDNS_DeregisterService(m, &m->SPSRecords); #else (void)oldstate; #endif mDNS_ReclaimLockAfterCallback(); } m->SleepState = SleepState_Transferring; if (m->SystemWakeOnLANEnabled && m->DelaySleep) { // If we just woke up moments ago, allow ten seconds for networking to stabilize before going back to sleep LogSPS("mDNSCoreMachineSleep: Re-sleeping immediately after waking; will delay for %d ticks", m->DelaySleep - m->timenow); m->SleepLimit = NonZeroTime(m->DelaySleep + mDNSPlatformOneSecond * 10); } else { m->DelaySleep = 0; m->SleepLimit = NonZeroTime(m->timenow + mDNSPlatformOneSecond * 10); m->mDNSStats.Sleeps++; BeginSleepProcessing(m); } #ifndef UNICAST_DISABLED SuspendLLQs(m); #endif #if APPLE_OSX_mDNSResponder RemoveAutoTunnel6Record(m); #endif LogSPS("mDNSCoreMachineSleep: m->SleepState %d (%s) seq %d", m->SleepState, m->SleepState == SleepState_Transferring ? "Transferring" : m->SleepState == SleepState_Sleeping ? "Sleeping" : "?", m->SleepSeqNum); mDNS_Unlock(m); } else if (!sleep) // Waking up { mDNSu32 slot; CacheGroup *cg; CacheRecord *cr; NetworkInterfaceInfo *intf; mDNSs32 currtime, diff; mDNS_Lock(m); // Reset SleepLimit back to 0 now that we're awake again. m->SleepLimit = 0; // If we were previously sleeping, but now we're not, increment m->SleepSeqNum to indicate that we're entering a new period of wakefulness if (m->SleepState != SleepState_Awake) { m->SleepState = SleepState_Awake; m->SleepSeqNum++; // If the machine wakes and then immediately tries to sleep again (e.g. a maintenance wake) // then we enforce a minimum delay of five seconds before we begin sleep processing. // This is to allow time for the Ethernet link to come up, DHCP to get an address, mDNS to issue queries, etc., // before we make our determination of whether there's a Sleep Proxy out there we should register with. m->DelaySleep = NonZeroTime(m->timenow + kDarkWakeDelaySleep); } if (m->SPSState == 3) { m->SPSState = 0; mDNSCoreBeSleepProxyServer_internal(m, m->SPSType, m->SPSPortability, m->SPSMarginalPower, m->SPSTotalPower, m->SPSFeatureFlags); } m->mDNSStats.Wakes++; m->DelayConflictProcessing = MAX_CONFLICT_PROCESSING_DELAYS; // ... and the same for NextSPSAttempt for (intf = GetFirstActiveInterface(m->HostInterfaces); intf; intf = GetFirstActiveInterface(intf->next)) intf->NextSPSAttempt = -1; // Restart unicast and multicast queries mDNSCoreRestartQueries(m); // and reactivtate service registrations m->NextSRVUpdate = NonZeroTime(m->timenow + mDNSPlatformOneSecond); LogInfo("mDNSCoreMachineSleep waking: NextSRVUpdate in %d %d", m->NextSRVUpdate - m->timenow, m->timenow); // 2. Re-validate our cache records currtime = mDNSPlatformUTC(); diff = currtime - m->TimeSlept; FORALL_CACHERECORDS(slot, cg, cr) { // Temporary fix: For unicast cache records, look at how much time we slept. // Adjust the RecvTime by the amount of time we slept so that we age the // cache record appropriately. If it is expired already, purge. If there // is a network change that happens after the wakeup, we might purge the // cache anyways and this helps only in the case where there are no network // changes across sleep/wakeup transition. // // Note: If there is a network/DNS server change that already happened and // these cache entries are already refreshed and we are getting a delayed // wake up notification, we might adjust the TimeRcvd based on the time slept // now which can cause the cache to purge pre-maturely. As this is not a very // common case, this should happen rarely. if (!cr->resrec.InterfaceID) { if (diff > 0) { mDNSu32 uTTL = RRUnadjustedTTL(cr->resrec.rroriginalttl); const mDNSs32 remain = uTTL - (m->timenow - cr->TimeRcvd) / mDNSPlatformOneSecond; // -if we have slept longer than the remaining TTL, purge and start fresh. // -if we have been sleeping for a long time, we could reduce TimeRcvd below by // a sufficiently big value which could cause the value to go into the future // because of the signed comparison of time. For this to happen, we should have been // sleeping really long (~24 days). For now, we want to be conservative and flush even // if we have slept for more than two days. if (diff >= remain || diff > (2 * 24 * 3600)) { LogInfo("mDNSCoreMachineSleep: %s: Purging cache entry SleptTime %d, Remaining TTL %d", CRDisplayString(m, cr), diff, remain); mDNS_PurgeCacheResourceRecord(m, cr); continue; } cr->TimeRcvd -= (diff * mDNSPlatformOneSecond); if (m->timenow - (cr->TimeRcvd + ((mDNSs32)uTTL * mDNSPlatformOneSecond)) >= 0) { LogInfo("mDNSCoreMachineSleep: %s: Purging after adjusting the remaining TTL %d by %d seconds", CRDisplayString(m, cr), remain, diff); mDNS_PurgeCacheResourceRecord(m, cr); } else { LogInfo("mDNSCoreMachineSleep: %s: Adjusted the remain ttl %u by %d seconds", CRDisplayString(m, cr), remain, diff); } } } else { mDNS_Reconfirm_internal(m, cr, kDefaultReconfirmTimeForWake); } } // 3. Retrigger probing and announcing for all our authoritative records for (rr = m->ResourceRecords; rr; rr=rr->next) { if (AuthRecord_uDNS(rr)) { ActivateUnicastRegistration(m, rr); } else { mDNSCoreRestartRegistration(m, rr, -1); } } // 4. Refresh NAT mappings // We don't want to have to assume that all hardware can necessarily keep accurate // track of passage of time while asleep, so on wake we refresh our NAT mappings. // We typically wake up with no interfaces active, so there's no need to rush to try to find our external address. // But if we do get a network configuration change, mDNSMacOSXNetworkChanged will call uDNS_SetupDNSConfig, which // will call mDNS_SetPrimaryInterfaceInfo, which will call RecreateNATMappings to refresh them, potentially sooner // than five seconds from now. LogInfo("mDNSCoreMachineSleep: recreating NAT mappings in 5 seconds"); RecreateNATMappings(m, mDNSPlatformOneSecond * 5); mDNS_Unlock(m); } } mDNSexport mDNSBool mDNSCoreReadyForSleep(mDNS *m, mDNSs32 now) { DNSQuestion *q; AuthRecord *rr; NetworkInterfaceInfo *intf; mDNS_Lock(m); if (m->DelaySleep) goto notready; // If we've not hit the sleep limit time, and it's not time for our next retry, we can skip these checks if (m->SleepLimit - now > 0 && m->NextScheduledSPRetry - now > 0) goto notready; m->NextScheduledSPRetry = now + 0x40000000UL; // See if we might need to retransmit any lost Sleep Proxy Registrations for (intf = GetFirstActiveInterface(m->HostInterfaces); intf; intf = GetFirstActiveInterface(intf->next)) if (intf->NextSPSAttempt >= 0) { if (now - intf->NextSPSAttemptTime >= 0) { LogSPS("mDNSCoreReadyForSleep: retrying for %s SPS %d try %d", intf->ifname, intf->NextSPSAttempt/3, intf->NextSPSAttempt); SendSPSRegistration(m, intf, zeroID); // Don't need to "goto notready" here, because if we do still have record registrations // that have not been acknowledged yet, we'll catch that in the record list scan below. } else if (m->NextScheduledSPRetry - intf->NextSPSAttemptTime > 0) m->NextScheduledSPRetry = intf->NextSPSAttemptTime; } // Scan list of interfaces, and see if we're still waiting for any sleep proxy resolves to complete for (intf = GetFirstActiveInterface(m->HostInterfaces); intf; intf = GetFirstActiveInterface(intf->next)) { int sps = (intf->NextSPSAttempt == 0) ? 0 : (intf->NextSPSAttempt-1)/3; if (intf->NetWakeResolve[sps].ThisQInterval >= 0) { LogSPS("mDNSCoreReadyForSleep: waiting for SPS Resolve %s %##s (%s)", intf->ifname, intf->NetWakeResolve[sps].qname.c, DNSTypeName(intf->NetWakeResolve[sps].qtype)); goto spsnotready; } } // Scan list of registered records for (rr = m->ResourceRecords; rr; rr = rr->next) if (!AuthRecord_uDNS(rr)) if (!mDNSOpaque64IsZero(&rr->updateIntID)) { LogSPS("mDNSCoreReadyForSleep: waiting for SPS updateIntID 0x%x 0x%x (updateid %d) %s", rr->updateIntID.l[1], rr->updateIntID.l[0], mDNSVal16(rr->updateid), ARDisplayString(m,rr)); goto spsnotready; } // Scan list of private LLQs, and make sure they've all completed their handshake with the server for (q = m->Questions; q; q = q->next) if (!mDNSOpaque16IsZero(q->TargetQID) && q->LongLived && q->ReqLease == 0 && q->tcp) { LogSPS("mDNSCoreReadyForSleep: waiting for LLQ %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); goto notready; } // Scan list of registered records for (rr = m->ResourceRecords; rr; rr = rr->next) if (AuthRecord_uDNS(rr)) { if (rr->state == regState_Refresh && rr->tcp) { LogSPS("mDNSCoreReadyForSleep: waiting for Record updateIntID 0x%x 0x%x (updateid %d) %s", rr->updateIntID.l[1], rr->updateIntID.l[0], mDNSVal16(rr->updateid), ARDisplayString(m,rr)); goto notready; } #if APPLE_OSX_mDNSResponder if (!RecordReadyForSleep(rr)) { LogSPS("mDNSCoreReadyForSleep: waiting for %s", ARDisplayString(m, rr)); goto notready; } #endif } mDNS_Unlock(m); return mDNStrue; spsnotready: // If we failed to complete sleep proxy registration within ten seconds, we give up on that // and allow up to ten seconds more to complete wide-area deregistration instead if (now - m->SleepLimit >= 0) { LogMsg("Failed to register with SPS, now sending goodbyes"); for (intf = GetFirstActiveInterface(m->HostInterfaces); intf; intf = GetFirstActiveInterface(intf->next)) if (intf->NetWakeBrowse.ThisQInterval >= 0) { LogSPS("ReadyForSleep mDNS_DeactivateNetWake %s %##s (%s)", intf->ifname, intf->NetWakeResolve[0].qname.c, DNSTypeName(intf->NetWakeResolve[0].qtype)); mDNS_DeactivateNetWake_internal(m, intf); } for (rr = m->ResourceRecords; rr; rr = rr->next) if (!AuthRecord_uDNS(rr)) if (!mDNSOpaque64IsZero(&rr->updateIntID)) { LogSPS("ReadyForSleep clearing updateIntID 0x%x 0x%x (updateid %d) for %s", rr->updateIntID.l[1], rr->updateIntID.l[0], mDNSVal16(rr->updateid), ARDisplayString(m, rr)); rr->updateIntID = zeroOpaque64; } // We'd really like to allow up to ten seconds more here, // but if we don't respond to the sleep notification within 30 seconds // we'll be put back to sleep forcibly without the chance to schedule the next maintenance wake. // Right now we wait 16 sec after wake for all the interfaces to come up, then we wait up to 10 seconds // more for SPS resolves and record registrations to complete, which puts us at 26 seconds. // If we allow just one more second to send our goodbyes, that puts us at 27 seconds. m->SleepLimit = now + mDNSPlatformOneSecond * 1; SendSleepGoodbyes(m, mDNStrue, mDNStrue); } notready: mDNS_Unlock(m); return mDNSfalse; } mDNSexport mDNSs32 mDNSCoreIntervalToNextWake(mDNS *const m, mDNSs32 now) { AuthRecord *ar; // Even when we have no wake-on-LAN-capable interfaces, or we failed to find a sleep proxy, or we have other // failure scenarios, we still want to wake up in at most 120 minutes, to see if the network environment has changed. // E.g. we might wake up and find no wireless network because the base station got rebooted just at that moment, // and if that happens we don't want to just give up and go back to sleep and never try again. mDNSs32 e = now + (120 * 60 * mDNSPlatformOneSecond); // Sleep for at most 120 minutes NATTraversalInfo *nat; for (nat = m->NATTraversals; nat; nat=nat->next) if (nat->Protocol && nat->ExpiryTime && nat->ExpiryTime - now > mDNSPlatformOneSecond*4) { mDNSs32 t = nat->ExpiryTime - (nat->ExpiryTime - now) / 10; // Wake up when 90% of the way to the expiry time if (e - t > 0) e = t; LogSPS("ComputeWakeTime: %p %s Int %5d Ext %5d Err %d Retry %5d Interval %5d Expire %5d Wake %5d", nat, nat->Protocol == NATOp_MapTCP ? "TCP" : "UDP", mDNSVal16(nat->IntPort), mDNSVal16(nat->ExternalPort), nat->Result, nat->retryPortMap ? (nat->retryPortMap - now) / mDNSPlatformOneSecond : 0, nat->retryInterval / mDNSPlatformOneSecond, nat->ExpiryTime ? (nat->ExpiryTime - now) / mDNSPlatformOneSecond : 0, (t - now) / mDNSPlatformOneSecond); } // This loop checks both the time we need to renew wide-area registrations, // and the time we need to renew Sleep Proxy registrations for (ar = m->ResourceRecords; ar; ar = ar->next) if (ar->expire && ar->expire - now > mDNSPlatformOneSecond*4) { mDNSs32 t = ar->expire - (ar->expire - now) / 10; // Wake up when 90% of the way to the expiry time if (e - t > 0) e = t; LogSPS("ComputeWakeTime: %p Int %7d Next %7d Expire %7d Wake %7d %s", ar, ar->ThisAPInterval / mDNSPlatformOneSecond, (ar->LastAPTime + ar->ThisAPInterval - now) / mDNSPlatformOneSecond, ar->expire ? (ar->expire - now) / mDNSPlatformOneSecond : 0, (t - now) / mDNSPlatformOneSecond, ARDisplayString(m, ar)); } return(e - now); } // *************************************************************************** #if COMPILER_LIKES_PRAGMA_MARK #pragma mark - #pragma mark - Packet Reception Functions #endif #define MustSendRecord(RR) ((RR)->NR_AnswerTo || (RR)->NR_AdditionalTo) mDNSlocal mDNSu8 *GenerateUnicastResponse(const DNSMessage *const query, const mDNSu8 *const end, const mDNSInterfaceID InterfaceID, mDNSBool LegacyQuery, DNSMessage *const response, AuthRecord *ResponseRecords) { mDNSu8 *responseptr = response->data; const mDNSu8 *const limit = response->data + sizeof(response->data); const mDNSu8 *ptr = query->data; AuthRecord *rr; mDNSu32 maxttl = 0x70000000; int i; // Initialize the response fields so we can answer the questions InitializeDNSMessage(&response->h, query->h.id, ResponseFlags); // *** // *** 1. Write out the list of questions we are actually going to answer with this packet // *** if (LegacyQuery) { maxttl = kStaticCacheTTL; for (i=0; ih.numQuestions; i++) // For each question... { DNSQuestion q; ptr = getQuestion(query, ptr, end, InterfaceID, &q); // get the question... if (!ptr) return(mDNSNULL); for (rr=ResponseRecords; rr; rr=rr->NextResponse) // and search our list of proposed answers { if (rr->NR_AnswerTo == ptr) // If we're going to generate a record answering this question { // then put the question in the question section responseptr = putQuestion(response, responseptr, limit, &q.qname, q.qtype, q.qclass); if (!responseptr) { debugf("GenerateUnicastResponse: Ran out of space for questions!"); return(mDNSNULL); } break; // break out of the ResponseRecords loop, and go on to the next question } } } if (response->h.numQuestions == 0) { LogMsg("GenerateUnicastResponse: ERROR! Why no questions?"); return(mDNSNULL); } } // *** // *** 2. Write Answers // *** for (rr=ResponseRecords; rr; rr=rr->NextResponse) if (rr->NR_AnswerTo) { mDNSu8 *p = PutResourceRecordTTL(response, responseptr, &response->h.numAnswers, &rr->resrec, maxttl < rr->resrec.rroriginalttl ? maxttl : rr->resrec.rroriginalttl); if (p) responseptr = p; else { debugf("GenerateUnicastResponse: Ran out of space for answers!"); response->h.flags.b[0] |= kDNSFlag0_TC; } } // *** // *** 3. Write Additionals // *** for (rr=ResponseRecords; rr; rr=rr->NextResponse) if (rr->NR_AdditionalTo && !rr->NR_AnswerTo) { mDNSu8 *p = PutResourceRecordTTL(response, responseptr, &response->h.numAdditionals, &rr->resrec, maxttl < rr->resrec.rroriginalttl ? maxttl : rr->resrec.rroriginalttl); if (p) responseptr = p; else debugf("GenerateUnicastResponse: No more space for additionals"); } return(responseptr); } // AuthRecord *our is our Resource Record // CacheRecord *pkt is the Resource Record from the response packet we've witnessed on the network // Returns 0 if there is no conflict // Returns +1 if there was a conflict and we won // Returns -1 if there was a conflict and we lost and have to rename mDNSlocal int CompareRData(const AuthRecord *const our, const CacheRecord *const pkt) { mDNSu8 ourdata[256], *ourptr = ourdata, *ourend; mDNSu8 pktdata[256], *pktptr = pktdata, *pktend; if (!our) { LogMsg("CompareRData ERROR: our is NULL"); return(+1); } if (!pkt) { LogMsg("CompareRData ERROR: pkt is NULL"); return(+1); } ourend = putRData(mDNSNULL, ourdata, ourdata + sizeof(ourdata), &our->resrec); pktend = putRData(mDNSNULL, pktdata, pktdata + sizeof(pktdata), &pkt->resrec); while (ourptr < ourend && pktptr < pktend && *ourptr == *pktptr) { ourptr++; pktptr++; } if (ourptr >= ourend && pktptr >= pktend) return(0); // If data identical, not a conflict if (ourptr >= ourend) return(-1); // Our data ran out first; We lost if (pktptr >= pktend) return(+1); // Packet data ran out first; We won if (*pktptr > *ourptr) return(-1); // Our data is numerically lower; We lost if (*pktptr < *ourptr) return(+1); // Packet data is numerically lower; We won LogMsg("CompareRData ERROR: Invalid state"); return(-1); } // See if we have an authoritative record that's identical to this packet record, // whose canonical DependentOn record is the specified master record. // The DependentOn pointer is typically used for the TXT record of service registrations // It indicates that there is no inherent conflict detection for the TXT record // -- it depends on the SRV record to resolve name conflicts // If we find any identical ResourceRecords in our authoritative list, then follow their DependentOn // pointer chain (if any) to make sure we reach the canonical DependentOn record // If the record has no DependentOn, then just return that record's pointer // Returns NULL if we don't have any local RRs that are identical to the one from the packet mDNSlocal mDNSBool MatchDependentOn(const mDNS *const m, const CacheRecord *const pktrr, const AuthRecord *const master) { const AuthRecord *r1; for (r1 = m->ResourceRecords; r1; r1=r1->next) { if (IdenticalResourceRecord(&r1->resrec, &pktrr->resrec)) { const AuthRecord *r2 = r1; while (r2->DependentOn) r2 = r2->DependentOn; if (r2 == master) return(mDNStrue); } } for (r1 = m->DuplicateRecords; r1; r1=r1->next) { if (IdenticalResourceRecord(&r1->resrec, &pktrr->resrec)) { const AuthRecord *r2 = r1; while (r2->DependentOn) r2 = r2->DependentOn; if (r2 == master) return(mDNStrue); } } return(mDNSfalse); } // Find the canonical RRSet pointer for this RR received in a packet. // If we find any identical AuthRecord in our authoritative list, then follow its RRSet // pointers (if any) to make sure we return the canonical member of this name/type/class // Returns NULL if we don't have any local RRs that are identical to the one from the packet mDNSlocal const AuthRecord *FindRRSet(const mDNS *const m, const CacheRecord *const pktrr) { const AuthRecord *rr; for (rr = m->ResourceRecords; rr; rr=rr->next) { if (IdenticalResourceRecord(&rr->resrec, &pktrr->resrec)) { while (rr->RRSet && rr != rr->RRSet) rr = rr->RRSet; return(rr); } } return(mDNSNULL); } // PacketRRConflict is called when we've received an RR (pktrr) which has the same name // as one of our records (our) but different rdata. // 1. If our record is not a type that's supposed to be unique, we don't care. // 2a. If our record is marked as dependent on some other record for conflict detection, ignore this one. // 2b. If the packet rr exactly matches one of our other RRs, and *that* record's DependentOn pointer // points to our record, ignore this conflict (e.g. the packet record matches one of our // TXT records, and that record is marked as dependent on 'our', its SRV record). // 3. If we have some *other* RR that exactly matches the one from the packet, and that record and our record // are members of the same RRSet, then this is not a conflict. mDNSlocal mDNSBool PacketRRConflict(const mDNS *const m, const AuthRecord *const our, const CacheRecord *const pktrr) { // If not supposed to be unique, not a conflict if (!(our->resrec.RecordType & kDNSRecordTypeUniqueMask)) return(mDNSfalse); // If a dependent record, not a conflict if (our->DependentOn || MatchDependentOn(m, pktrr, our)) return(mDNSfalse); else { // If the pktrr matches a member of ourset, not a conflict const AuthRecord *ourset = our->RRSet ? our->RRSet : our; const AuthRecord *pktset = FindRRSet(m, pktrr); if (pktset == ourset) return(mDNSfalse); // For records we're proxying, where we don't know the full // relationship between the records, having any matching record // in our AuthRecords list is sufficient evidence of non-conflict if (our->WakeUp.HMAC.l[0] && pktset) return(mDNSfalse); } // Okay, this is a conflict return(mDNStrue); } // Note: ResolveSimultaneousProbe calls mDNS_Deregister_internal which can call a user callback, which may change // the record list and/or question list. // Any code walking either list must use the CurrentQuestion and/or CurrentRecord mechanism to protect against this. mDNSlocal void ResolveSimultaneousProbe(mDNS *const m, const DNSMessage *const query, const mDNSu8 *const end, DNSQuestion *q, AuthRecord *our) { int i; const mDNSu8 *ptr = LocateAuthorities(query, end); mDNSBool FoundUpdate = mDNSfalse; for (i = 0; i < query->h.numAuthorities; i++) { ptr = GetLargeResourceRecord(m, query, ptr, end, q->InterfaceID, kDNSRecordTypePacketAuth, &m->rec); if (!ptr) break; if (m->rec.r.resrec.RecordType != kDNSRecordTypePacketNegative && ResourceRecordAnswersQuestion(&m->rec.r.resrec, q)) { FoundUpdate = mDNStrue; if (PacketRRConflict(m, our, &m->rec.r)) { int result = (int)our->resrec.rrclass - (int)m->rec.r.resrec.rrclass; if (!result) result = (int)our->resrec.rrtype - (int)m->rec.r.resrec.rrtype; if (!result) result = CompareRData(our, &m->rec.r); if (result) { const char *const msg = (result < 0) ? "lost:" : (result > 0) ? "won: " : "tie: "; LogMsg("ResolveSimultaneousProbe: %p Pkt Record: %08lX %s", q->InterfaceID, m->rec.r.resrec.rdatahash, CRDisplayString(m, &m->rec.r)); LogMsg("ResolveSimultaneousProbe: %p Our Record %d %s %08lX %s", our->resrec.InterfaceID, our->ProbeCount, msg, our->resrec.rdatahash, ARDisplayString(m, our)); } // If we lost the tie-break for simultaneous probes, we don't immediately give up, because we might be seeing stale packets on the network. // Instead we pause for one second, to give the other host (if real) a chance to establish its name, and then try probing again. // If there really is another live host out there with the same name, it will answer our probes and we'll then rename. if (result < 0) { m->SuppressProbes = NonZeroTime(m->timenow + mDNSPlatformOneSecond); our->ProbeCount = DefaultProbeCountForTypeUnique; our->AnnounceCount = InitialAnnounceCount; InitializeLastAPTime(m, our); goto exit; } } #if 0 else { LogMsg("ResolveSimultaneousProbe: %p Pkt Record: %08lX %s", q->InterfaceID, m->rec.r.resrec.rdatahash, CRDisplayString(m, &m->rec.r)); LogMsg("ResolveSimultaneousProbe: %p Our Record %d ign: %08lX %s", our->resrec.InterfaceID, our->ProbeCount, our->resrec.rdatahash, ARDisplayString(m, our)); } #endif } m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it } if (!FoundUpdate) LogInfo("ResolveSimultaneousProbe: %##s (%s): No Update Record found", our->resrec.name->c, DNSTypeName(our->resrec.rrtype)); exit: m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it } mDNSlocal CacheRecord *FindIdenticalRecordInCache(const mDNS *const m, const ResourceRecord *const pktrr) { CacheGroup *cg = CacheGroupForRecord(m, pktrr); CacheRecord *rr; mDNSBool match; for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) { if (!pktrr->InterfaceID) { mDNSu16 id1 = (pktrr->rDNSServer ? pktrr->rDNSServer->resGroupID : 0); mDNSu16 id2 = (rr->resrec.rDNSServer ? rr->resrec.rDNSServer->resGroupID : 0); match = (id1 == id2); } else match = (pktrr->InterfaceID == rr->resrec.InterfaceID); if (match && IdenticalSameNameRecord(pktrr, &rr->resrec)) break; } return(rr); } mDNSlocal void DeregisterProxyRecord(mDNS *const m, AuthRecord *const rr) { rr->WakeUp.HMAC = zeroEthAddr; // Clear HMAC so that mDNS_Deregister_internal doesn't waste packets trying to wake this host rr->RequireGoodbye = mDNSfalse; // and we don't want to send goodbye for it mDNS_Deregister_internal(m, rr, mDNS_Dereg_normal); SetSPSProxyListChanged(m->rec.r.resrec.InterfaceID); } mDNSlocal void ClearKeepaliveProxyRecords(mDNS *const m, const OwnerOptData *const owner, AuthRecord *const thelist, const mDNSInterfaceID InterfaceID) { if (m->CurrentRecord) LogMsg("ClearKeepaliveProxyRecords ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); m->CurrentRecord = thelist; // Normally, the RDATA of the keepalive record will be different each time and hence we always // clean up the keepalive record. while (m->CurrentRecord) { AuthRecord *const rr = m->CurrentRecord; if (InterfaceID == rr->resrec.InterfaceID && mDNSSameEthAddress(&owner->HMAC, &rr->WakeUp.HMAC)) { if (mDNS_KeepaliveRecord(&m->rec.r.resrec)) { LogSPS("ClearKeepaliveProxyRecords: Removing %3d H-MAC %.6a I-MAC %.6a %d %d %s", m->ProxyRecords, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, rr->WakeUp.seq, owner->seq, ARDisplayString(m, rr)); DeregisterProxyRecord(m, rr); } } // Mustn't advance m->CurrentRecord until *after* mDNS_Deregister_internal, because // new records could have been added to the end of the list as a result of that call. if (m->CurrentRecord == rr) // If m->CurrentRecord was not advanced for us, do it now m->CurrentRecord = rr->next; } } // Called from mDNSCoreReceiveUpdate when we get a sleep proxy registration request, // to check our lists and discard any stale duplicates of this record we already have mDNSlocal void ClearIdenticalProxyRecords(mDNS *const m, const OwnerOptData *const owner, AuthRecord *const thelist) { if (m->CurrentRecord) LogMsg("ClearIdenticalProxyRecords ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); m->CurrentRecord = thelist; while (m->CurrentRecord) { AuthRecord *const rr = m->CurrentRecord; if (m->rec.r.resrec.InterfaceID == rr->resrec.InterfaceID && mDNSSameEthAddress(&owner->HMAC, &rr->WakeUp.HMAC)) if (IdenticalResourceRecord(&rr->resrec, &m->rec.r.resrec)) { LogSPS("ClearIdenticalProxyRecords: Removing %3d H-MAC %.6a I-MAC %.6a %d %d %s", m->ProxyRecords, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, rr->WakeUp.seq, owner->seq, ARDisplayString(m, rr)); DeregisterProxyRecord(m, rr); } // Mustn't advance m->CurrentRecord until *after* mDNS_Deregister_internal, because // new records could have been added to the end of the list as a result of that call. if (m->CurrentRecord == rr) // If m->CurrentRecord was not advanced for us, do it now m->CurrentRecord = rr->next; } } // Called from ProcessQuery when we get an mDNS packet with an owner record in it mDNSlocal void ClearProxyRecords(mDNS *const m, const OwnerOptData *const owner, AuthRecord *const thelist) { if (m->CurrentRecord) LogMsg("ClearProxyRecords ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); m->CurrentRecord = thelist; while (m->CurrentRecord) { AuthRecord *const rr = m->CurrentRecord; if (m->rec.r.resrec.InterfaceID == rr->resrec.InterfaceID && mDNSSameEthAddress(&owner->HMAC, &rr->WakeUp.HMAC)) if (owner->seq != rr->WakeUp.seq || m->timenow - rr->TimeRcvd > mDNSPlatformOneSecond * 60) { if (rr->AddressProxy.type == mDNSAddrType_IPv6) { // We don't do this here because we know that the host is waking up at this point, so we don't send // Unsolicited Neighbor Advertisements -- even Neighbor Advertisements agreeing with what the host should be // saying itself -- because it can cause some IPv6 stacks to falsely conclude that there's an address conflict. #if MDNS_USE_Unsolicited_Neighbor_Advertisements LogSPS("NDP Announcement -- Releasing traffic for H-MAC %.6a I-MAC %.6a %s", &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, ARDisplayString(m,rr)); SendNDP(m, NDP_Adv, NDP_Override, rr, &rr->AddressProxy.ip.v6, &rr->WakeUp.IMAC, &AllHosts_v6, &AllHosts_v6_Eth); #endif } LogSPS("ClearProxyRecords: Removing %3d AC %2d %02X H-MAC %.6a I-MAC %.6a %d %d %s", m->ProxyRecords, rr->AnnounceCount, rr->resrec.RecordType, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, rr->WakeUp.seq, owner->seq, ARDisplayString(m, rr)); if (rr->resrec.RecordType == kDNSRecordTypeDeregistering) rr->resrec.RecordType = kDNSRecordTypeShared; rr->WakeUp.HMAC = zeroEthAddr; // Clear HMAC so that mDNS_Deregister_internal doesn't waste packets trying to wake this host rr->RequireGoodbye = mDNSfalse; // and we don't want to send goodbye for it, since real host is now back and functional mDNS_Deregister_internal(m, rr, mDNS_Dereg_normal); SetSPSProxyListChanged(m->rec.r.resrec.InterfaceID); } // Mustn't advance m->CurrentRecord until *after* mDNS_Deregister_internal, because // new records could have been added to the end of the list as a result of that call. if (m->CurrentRecord == rr) // If m->CurrentRecord was not advanced for us, do it now m->CurrentRecord = rr->next; } } // ProcessQuery examines a received query to see if we have any answers to give mDNSlocal mDNSu8 *ProcessQuery(mDNS *const m, const DNSMessage *const query, const mDNSu8 *const end, const mDNSAddr *srcaddr, const mDNSInterfaceID InterfaceID, mDNSBool LegacyQuery, mDNSBool QueryWasMulticast, mDNSBool QueryWasLocalUnicast, DNSMessage *const response) { mDNSBool FromLocalSubnet = srcaddr && mDNS_AddressIsLocalSubnet(m, InterfaceID, srcaddr); AuthRecord *ResponseRecords = mDNSNULL; AuthRecord **nrp = &ResponseRecords; #if POOF_ENABLED CacheRecord *ExpectedAnswers = mDNSNULL; // Records in our cache we expect to see updated CacheRecord **eap = &ExpectedAnswers; #endif // POOF_ENABLED DNSQuestion *DupQuestions = mDNSNULL; // Our questions that are identical to questions in this packet DNSQuestion **dqp = &DupQuestions; mDNSs32 delayresponse = 0; mDNSBool SendLegacyResponse = mDNSfalse; const mDNSu8 *ptr; mDNSu8 *responseptr = mDNSNULL; AuthRecord *rr; int i; CacheRecord *McastNSEC3Records = mDNSNULL; // *** // *** 1. Look in Additional Section for an OPT record // *** ptr = LocateOptRR(query, end, DNSOpt_OwnerData_ID_Space); if (ptr) { ptr = GetLargeResourceRecord(m, query, ptr, end, InterfaceID, kDNSRecordTypePacketAdd, &m->rec); if (ptr && m->rec.r.resrec.RecordType != kDNSRecordTypePacketNegative && m->rec.r.resrec.rrtype == kDNSType_OPT) { const rdataOPT *opt; const rdataOPT *const e = (const rdataOPT *)&m->rec.r.resrec.rdata->u.data[m->rec.r.resrec.rdlength]; // Find owner sub-option(s). We verify that the MAC is non-zero, otherwise we could inadvertently // delete all our own AuthRecords (which are identified by having zero MAC tags on them). for (opt = &m->rec.r.resrec.rdata->u.opt[0]; opt < e; opt++) if (opt->opt == kDNSOpt_Owner && opt->u.owner.vers == 0 && opt->u.owner.HMAC.l[0]) { ClearProxyRecords(m, &opt->u.owner, m->DuplicateRecords); ClearProxyRecords(m, &opt->u.owner, m->ResourceRecords); } } m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it } // // Look in Authority Section for NSEC3 record // mDNSParseNSEC3Records(m, query, end, InterfaceID, &McastNSEC3Records); // *** // *** 2. Parse Question Section and mark potential answers // *** ptr = query->data; for (i=0; ih.numQuestions; i++) // For each question... { mDNSBool QuestionNeedsMulticastResponse; int NumAnswersForThisQuestion = 0; AuthRecord *NSECAnswer = mDNSNULL; DNSQuestion pktq, *q; ptr = getQuestion(query, ptr, end, InterfaceID, &pktq); // get the question... if (!ptr) goto exit; pktq.AnonInfo = mDNSNULL; if (McastNSEC3Records) InitializeAnonInfoForQuestion(m, &McastNSEC3Records, &pktq); // The only queries that *need* a multicast response are: // * Queries sent via multicast // * from port 5353 // * that don't have the kDNSQClass_UnicastResponse bit set // These queries need multicast responses because other clients will: // * suppress their own identical questions when they see these questions, and // * expire their cache records if they don't see the expected responses // For other queries, we may still choose to send the occasional multicast response anyway, // to keep our neighbours caches warm, and for ongoing conflict detection. QuestionNeedsMulticastResponse = QueryWasMulticast && !LegacyQuery && !(pktq.qclass & kDNSQClass_UnicastResponse); if (pktq.qclass & kDNSQClass_UnicastResponse) m->mDNSStats.UnicastBitInQueries++; else m->mDNSStats.NormalQueries++; // Clear the UnicastResponse flag -- don't want to confuse the rest of the code that follows later pktq.qclass &= ~kDNSQClass_UnicastResponse; // Note: We use the m->CurrentRecord mechanism here because calling ResolveSimultaneousProbe // can result in user callbacks which may change the record list and/or question list. // Also note: we just mark potential answer records here, without trying to build the // "ResponseRecords" list, because we don't want to risk user callbacks deleting records // from that list while we're in the middle of trying to build it. if (m->CurrentRecord) LogMsg("ProcessQuery ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); m->CurrentRecord = m->ResourceRecords; while (m->CurrentRecord) { rr = m->CurrentRecord; m->CurrentRecord = rr->next; if (AnyTypeRecordAnswersQuestion(&rr->resrec, &pktq) && (QueryWasMulticast || QueryWasLocalUnicast || rr->AllowRemoteQuery)) { m->mDNSStats.MatchingAnswersForQueries++; if (RRTypeAnswersQuestionType(&rr->resrec, pktq.qtype)) { if (rr->resrec.RecordType == kDNSRecordTypeUnique) ResolveSimultaneousProbe(m, query, end, &pktq, rr); else if (ResourceRecordIsValidAnswer(rr)) { NumAnswersForThisQuestion++; // As we have verified this question to be part of the same subset, // set the anonymous data which is needed below when walk the cache // records to see what answers we should be expecting. The cache records // may cache only the nsec3RR and not the anonymous data itself. if (pktq.AnonInfo && rr->resrec.AnonInfo) SetAnonData(&pktq, &rr->resrec, mDNStrue); // Note: We should check here if this is a probe-type query, and if so, generate an immediate // unicast answer back to the source, because timeliness in answering probes is important. // Notes: // NR_AnswerTo pointing into query packet means "answer via immediate legacy unicast" (may *also* choose to multicast) // NR_AnswerTo == NR_AnswerUnicast means "answer via delayed unicast" (to modern querier; may promote to multicast instead) // NR_AnswerTo == NR_AnswerMulticast means "definitely answer via multicast" (can't downgrade to unicast later) // If we're not multicasting this record because the kDNSQClass_UnicastResponse bit was set, // but the multicast querier is not on a matching subnet (e.g. because of overlaid subnets on one link) // then we'll multicast it anyway (if we unicast, the receiver will ignore it because it has an apparently non-local source) if (QuestionNeedsMulticastResponse || (!FromLocalSubnet && QueryWasMulticast && !LegacyQuery)) { // We only mark this question for sending if it is at least one second since the last time we multicast it // on this interface. If it is more than a second, or LastMCInterface is different, then we may multicast it. // This is to guard against the case where someone blasts us with queries as fast as they can. if ((mDNSu32)(m->timenow - rr->LastMCTime) >= (mDNSu32)mDNSPlatformOneSecond || (rr->LastMCInterface != mDNSInterfaceMark && rr->LastMCInterface != InterfaceID)) rr->NR_AnswerTo = NR_AnswerMulticast; } else if (!rr->NR_AnswerTo) rr->NR_AnswerTo = LegacyQuery ? ptr : NR_AnswerUnicast; } } else if ((rr->resrec.RecordType & kDNSRecordTypeActiveUniqueMask) && ResourceRecordIsValidAnswer(rr)) { // If we don't have any answers for this question, but we do own another record with the same name, // then we'll want to mark it to generate an NSEC record on this interface if (!NSECAnswer) NSECAnswer = rr; } } } if (NumAnswersForThisQuestion == 0 && NSECAnswer) { NumAnswersForThisQuestion++; NSECAnswer->SendNSECNow = InterfaceID; m->NextScheduledResponse = m->timenow; } // If we couldn't answer this question, someone else might be able to, // so use random delay on response to reduce collisions if (NumAnswersForThisQuestion == 0) delayresponse = mDNSPlatformOneSecond; // Divided by 50 = 20ms if (query->h.flags.b[0] & kDNSFlag0_TC) m->mDNSStats.KnownAnswerMultiplePkts++; // We only do the following accelerated cache expiration and duplicate question suppression processing // for non-truncated multicast queries with multicast responses. // For any query generating a unicast response we don't do this because we can't assume we will see the response. // For truncated queries we don't do this because a response we're expecting might be suppressed by a subsequent // known-answer packet, and when there's packet loss we can't safely assume we'll receive *all* known-answer packets. if (QuestionNeedsMulticastResponse && !(query->h.flags.b[0] & kDNSFlag0_TC)) { #if POOF_ENABLED CacheGroup *cg = CacheGroupForName(m, pktq.qnamehash, &pktq.qname); CacheRecord *cr; // Make a list indicating which of our own cache records we expect to see updated as a result of this query // Note: Records larger than 1K are not habitually multicast, so don't expect those to be updated for (cr = cg ? cg->members : mDNSNULL; cr; cr=cr->next) if (SameNameRecordAnswersQuestion(&cr->resrec, &pktq) && cr->resrec.rdlength <= SmallRecordLimit) if (!cr->NextInKAList && eap != &cr->NextInKAList) { *eap = cr; eap = &cr->NextInKAList; } #endif // POOF_ENABLED // Check if this question is the same as any of mine. // We only do this for non-truncated queries. Right now it would be too complicated to try // to keep track of duplicate suppression state between multiple packets, especially when we // can't guarantee to receive all of the Known Answer packets that go with a particular query. // For anonymous question, the duplicate suppressesion should happen if the // question belongs in the same group. As the group is expected to be // small, we don't do the optimization for now. if (!pktq.AnonInfo) { for (q = m->Questions; q; q=q->next) if (!q->Target.type && ActiveQuestion(q) && m->timenow - q->LastQTxTime > mDNSPlatformOneSecond / 4) if (!q->InterfaceID || q->InterfaceID == InterfaceID) if (q->NextInDQList == mDNSNULL && dqp != &q->NextInDQList) if (q->qtype == pktq.qtype && q->qclass == pktq.qclass && q->qnamehash == pktq.qnamehash && SameDomainName(&q->qname, &pktq.qname)) { *dqp = q; dqp = &q->NextInDQList; } } } if (pktq.AnonInfo) { FreeAnonInfo(pktq.AnonInfo); } } // *** // *** 3. Now we can safely build the list of marked answers // *** for (rr = m->ResourceRecords; rr; rr=rr->next) // Now build our list of potential answers if (rr->NR_AnswerTo) // If we marked the record... AddRecordToResponseList(&nrp, rr, mDNSNULL); // ... add it to the list // *** // *** 4. Add additional records // *** AddAdditionalsToResponseList(m, ResponseRecords, &nrp, InterfaceID); // *** // *** 5. Parse Answer Section and cancel any records disallowed by Known-Answer list // *** for (i=0; ih.numAnswers; i++) // For each record in the query's answer section... { // Get the record... CacheRecord *ourcacherr; ptr = GetLargeResourceRecord(m, query, ptr, end, InterfaceID, kDNSRecordTypePacketAns, &m->rec); if (!ptr) goto exit; if (m->rec.r.resrec.RecordType != kDNSRecordTypePacketNegative) { // See if this Known-Answer suppresses any of our currently planned answers for (rr=ResponseRecords; rr; rr=rr->NextResponse) { if (MustSendRecord(rr) && ShouldSuppressKnownAnswer(&m->rec.r, rr)) { m->mDNSStats.KnownAnswerSuppressions++; rr->NR_AnswerTo = mDNSNULL; rr->NR_AdditionalTo = mDNSNULL; } } // See if this Known-Answer suppresses any previously scheduled answers (for multi-packet KA suppression) for (rr=m->ResourceRecords; rr; rr=rr->next) { // If we're planning to send this answer on this interface, and only on this interface, then allow KA suppression if (rr->ImmedAnswer == InterfaceID && ShouldSuppressKnownAnswer(&m->rec.r, rr)) { if (srcaddr->type == mDNSAddrType_IPv4) { if (mDNSSameIPv4Address(rr->v4Requester, srcaddr->ip.v4)) rr->v4Requester = zerov4Addr; } else if (srcaddr->type == mDNSAddrType_IPv6) { if (mDNSSameIPv6Address(rr->v6Requester, srcaddr->ip.v6)) rr->v6Requester = zerov6Addr; } if (mDNSIPv4AddressIsZero(rr->v4Requester) && mDNSIPv6AddressIsZero(rr->v6Requester)) { m->mDNSStats.KnownAnswerSuppressions++; rr->ImmedAnswer = mDNSNULL; rr->ImmedUnicast = mDNSfalse; #if MDNS_LOG_ANSWER_SUPPRESSION_TIMES LogMsg("Suppressed after%4d: %s", m->timenow - rr->ImmedAnswerMarkTime, ARDisplayString(m, rr)); #endif } } } ourcacherr = FindIdenticalRecordInCache(m, &m->rec.r.resrec); #if POOF_ENABLED // Having built our ExpectedAnswers list from the questions in this packet, we then remove // any records that are suppressed by the Known Answer list in this packet. eap = &ExpectedAnswers; while (*eap) { CacheRecord *cr = *eap; if (cr->resrec.InterfaceID == InterfaceID && IdenticalResourceRecord(&m->rec.r.resrec, &cr->resrec)) { *eap = cr->NextInKAList; cr->NextInKAList = mDNSNULL; } else eap = &cr->NextInKAList; } #endif // POOF_ENABLED // See if this Known-Answer is a surprise to us. If so, we shouldn't suppress our own query. if (!ourcacherr) { dqp = &DupQuestions; while (*dqp) { DNSQuestion *q = *dqp; if (ResourceRecordAnswersQuestion(&m->rec.r.resrec, q)) { *dqp = q->NextInDQList; q->NextInDQList = mDNSNULL; } else dqp = &q->NextInDQList; } } } m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it } // *** // *** 6. Cancel any additionals that were added because of now-deleted records // *** for (rr=ResponseRecords; rr; rr=rr->NextResponse) if (rr->NR_AdditionalTo && !MustSendRecord(rr->NR_AdditionalTo)) { rr->NR_AnswerTo = mDNSNULL; rr->NR_AdditionalTo = mDNSNULL; } // *** // *** 7. Mark the send flags on the records we plan to send // *** for (rr=ResponseRecords; rr; rr=rr->NextResponse) { if (rr->NR_AnswerTo) { mDNSBool SendMulticastResponse = mDNSfalse; // Send modern multicast response mDNSBool SendUnicastResponse = mDNSfalse; // Send modern unicast response (not legacy unicast response) // If it's been one TTL/4 since we multicast this, then send a multicast response // for conflict detection, etc. if ((mDNSu32)(m->timenow - rr->LastMCTime) >= (mDNSu32)TicksTTL(rr)/4) { SendMulticastResponse = mDNStrue; // If this record was marked for modern (delayed) unicast response, then mark it as promoted to // multicast response instead (don't want to end up ALSO setting SendUnicastResponse in the check below). // If this record was marked for legacy unicast response, then we mustn't change the NR_AnswerTo value. if (rr->NR_AnswerTo == NR_AnswerUnicast) { m->mDNSStats.UnicastDemotedToMulticast++; rr->NR_AnswerTo = NR_AnswerMulticast; } } // If the client insists on a multicast response, then we'd better send one if (rr->NR_AnswerTo == NR_AnswerMulticast) { m->mDNSStats.MulticastResponses++; SendMulticastResponse = mDNStrue; } else if (rr->NR_AnswerTo == NR_AnswerUnicast) { m->mDNSStats.UnicastResponses++; SendUnicastResponse = mDNStrue; } else if (rr->NR_AnswerTo) { SendLegacyResponse = mDNStrue; } if (SendMulticastResponse || SendUnicastResponse) { #if MDNS_LOG_ANSWER_SUPPRESSION_TIMES rr->ImmedAnswerMarkTime = m->timenow; #endif m->NextScheduledResponse = m->timenow; // If we're already planning to send this on another interface, just send it on all interfaces if (rr->ImmedAnswer && rr->ImmedAnswer != InterfaceID) rr->ImmedAnswer = mDNSInterfaceMark; else { rr->ImmedAnswer = InterfaceID; // Record interface to send it on if (SendUnicastResponse) rr->ImmedUnicast = mDNStrue; if (srcaddr->type == mDNSAddrType_IPv4) { if (mDNSIPv4AddressIsZero(rr->v4Requester)) rr->v4Requester = srcaddr->ip.v4; else if (!mDNSSameIPv4Address(rr->v4Requester, srcaddr->ip.v4)) rr->v4Requester = onesIPv4Addr; } else if (srcaddr->type == mDNSAddrType_IPv6) { if (mDNSIPv6AddressIsZero(rr->v6Requester)) rr->v6Requester = srcaddr->ip.v6; else if (!mDNSSameIPv6Address(rr->v6Requester, srcaddr->ip.v6)) rr->v6Requester = onesIPv6Addr; } } } // If TC flag is set, it means we should expect that additional known answers may be coming in another packet, // so we allow roughly half a second before deciding to reply (we've observed inter-packet delays of 100-200ms on 802.11) // else, if record is a shared one, spread responses over 100ms to avoid implosion of simultaneous responses // else, for a simple unique record reply, we can reply immediately; no need for delay if (query->h.flags.b[0] & kDNSFlag0_TC) delayresponse = mDNSPlatformOneSecond * 20; // Divided by 50 = 400ms else if (rr->resrec.RecordType == kDNSRecordTypeShared) delayresponse = mDNSPlatformOneSecond; // Divided by 50 = 20ms } else if (rr->NR_AdditionalTo && rr->NR_AdditionalTo->NR_AnswerTo == NR_AnswerMulticast) { // Since additional records are an optimization anyway, we only ever send them on one interface at a time // If two clients on different interfaces do queries that invoke the same optional additional answer, // then the earlier client is out of luck rr->ImmedAdditional = InterfaceID; // No need to set m->NextScheduledResponse here // We'll send these additional records when we send them, or not, as the case may be } } // *** // *** 8. If we think other machines are likely to answer these questions, set our packet suppression timer // *** if (delayresponse && (!m->SuppressSending || (m->SuppressSending - m->timenow) < (delayresponse + 49) / 50)) { #if MDNS_LOG_ANSWER_SUPPRESSION_TIMES mDNSs32 oldss = m->SuppressSending; if (oldss && delayresponse) LogMsg("Current SuppressSending delay%5ld; require%5ld", m->SuppressSending - m->timenow, (delayresponse + 49) / 50); #endif // Pick a random delay: // We start with the base delay chosen above (typically either 1 second or 20 seconds), // and add a random value in the range 0-5 seconds (making 1-6 seconds or 20-25 seconds). // This is an integer value, with resolution determined by the platform clock rate. // We then divide that by 50 to get the delay value in ticks. We defer the division until last // to get better results on platforms with coarse clock granularity (e.g. ten ticks per second). // The +49 before dividing is to ensure we round up, not down, to ensure that even // on platforms where the native clock rate is less than fifty ticks per second, // we still guarantee that the final calculated delay is at least one platform tick. // We want to make sure we don't ever allow the delay to be zero ticks, // because if that happens we'll fail the Bonjour Conformance Test. // Our final computed delay is 20-120ms for normal delayed replies, // or 400-500ms in the case of multi-packet known-answer lists. m->SuppressSending = m->timenow + (delayresponse + (mDNSs32)mDNSRandom((mDNSu32)mDNSPlatformOneSecond*5) + 49) / 50; if (m->SuppressSending == 0) m->SuppressSending = 1; #if MDNS_LOG_ANSWER_SUPPRESSION_TIMES if (oldss && delayresponse) LogMsg("Set SuppressSending to %5ld", m->SuppressSending - m->timenow); #endif } // *** // *** 9. If query is from a legacy client, or from a new client requesting a unicast reply, then generate a unicast response too // *** if (SendLegacyResponse) responseptr = GenerateUnicastResponse(query, end, InterfaceID, LegacyQuery, response, ResponseRecords); exit: m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it // *** // *** 10. Finally, clear our link chains ready for use next time // *** while (ResponseRecords) { rr = ResponseRecords; ResponseRecords = rr->NextResponse; rr->NextResponse = mDNSNULL; rr->NR_AnswerTo = mDNSNULL; rr->NR_AdditionalTo = mDNSNULL; } #if POOF_ENABLED while (ExpectedAnswers) { CacheRecord *cr = ExpectedAnswers; ExpectedAnswers = cr->NextInKAList; cr->NextInKAList = mDNSNULL; // For non-truncated queries, we can definitively say that we should expect // to be seeing a response for any records still left in the ExpectedAnswers list if (!(query->h.flags.b[0] & kDNSFlag0_TC)) if (cr->UnansweredQueries == 0 || m->timenow - cr->LastUnansweredTime >= mDNSPlatformOneSecond * 3/4) { cr->UnansweredQueries++; cr->LastUnansweredTime = m->timenow; if (cr->UnansweredQueries > 1) debugf("ProcessQuery: UnansweredQueries %lu %s", cr->UnansweredQueries, CRDisplayString(m, cr)); SetNextCacheCheckTimeForRecord(m, cr); } // If we've seen multiple unanswered queries for this record, // then mark it to expire in five seconds if we don't get a response by then. if (cr->UnansweredQueries >= MaxUnansweredQueries) { // Only show debugging message if this record was not about to expire anyway if (RRExpireTime(cr) - m->timenow > (mDNSs32) kDefaultReconfirmTimeForNoAnswer * 4 / 3 + mDNSPlatformOneSecond) LogInfo("ProcessQuery: UnansweredQueries %lu interface %lu TTL %lu mDNS_Reconfirm() for %s", cr->UnansweredQueries, InterfaceID, (RRExpireTime(cr) - m->timenow + mDNSPlatformOneSecond-1) / mDNSPlatformOneSecond, CRDisplayString(m, cr)); m->mDNSStats.PoofCacheDeletions++; mDNS_Reconfirm_internal(m, cr, kDefaultReconfirmTimeForNoAnswer); } } #endif // POOF_ENABLED while (DupQuestions) { DNSQuestion *q = DupQuestions; DupQuestions = q->NextInDQList; q->NextInDQList = mDNSNULL; RecordDupSuppressInfo(q->DupSuppress, m->timenow, InterfaceID, srcaddr->type); debugf("ProcessQuery: Recorded DSI for %##s (%s) on %p/%s", q->qname.c, DNSTypeName(q->qtype), InterfaceID, srcaddr->type == mDNSAddrType_IPv4 ? "v4" : "v6"); } if (McastNSEC3Records) { debugf("ProcessQuery: McastNSEC3Records not used"); FreeNSECRecords(m, McastNSEC3Records); } return(responseptr); } mDNSlocal void mDNSCoreReceiveQuery(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end, const mDNSAddr *srcaddr, const mDNSIPPort srcport, const mDNSAddr *dstaddr, mDNSIPPort dstport, const mDNSInterfaceID InterfaceID) { mDNSu8 *responseend = mDNSNULL; mDNSBool QueryWasLocalUnicast = srcaddr && dstaddr && !mDNSAddrIsDNSMulticast(dstaddr) && mDNS_AddressIsLocalSubnet(m, InterfaceID, srcaddr); if (!dstaddr || (!InterfaceID && mDNSAddrIsDNSMulticast(dstaddr))) { const char *const reason = !dstaddr ? "Received over TCP connection" : "Multicast, but no InterfaceID"; LogMsg("Ignoring Query from %#-15a:%-5d to %#-15a:%-5d on 0x%p with " "%2d Question%s %2d Answer%s %2d Authorit%s %2d Additional%s %d bytes (%s)", srcaddr, mDNSVal16(srcport), dstaddr, mDNSVal16(dstport), InterfaceID, msg->h.numQuestions, msg->h.numQuestions == 1 ? ", " : "s,", msg->h.numAnswers, msg->h.numAnswers == 1 ? ", " : "s,", msg->h.numAuthorities, msg->h.numAuthorities == 1 ? "y, " : "ies,", msg->h.numAdditionals, msg->h.numAdditionals == 1 ? " " : "s", end - msg->data, reason); return; } verbosedebugf("Received Query from %#-15a:%-5d to %#-15a:%-5d on 0x%p with " "%2d Question%s %2d Answer%s %2d Authorit%s %2d Additional%s %d bytes", srcaddr, mDNSVal16(srcport), dstaddr, mDNSVal16(dstport), InterfaceID, msg->h.numQuestions, msg->h.numQuestions == 1 ? ", " : "s,", msg->h.numAnswers, msg->h.numAnswers == 1 ? ", " : "s,", msg->h.numAuthorities, msg->h.numAuthorities == 1 ? "y, " : "ies,", msg->h.numAdditionals, msg->h.numAdditionals == 1 ? " " : "s", end - msg->data); responseend = ProcessQuery(m, msg, end, srcaddr, InterfaceID, !mDNSSameIPPort(srcport, MulticastDNSPort), mDNSAddrIsDNSMulticast(dstaddr), QueryWasLocalUnicast, &m->omsg); if (responseend) // If responseend is non-null, that means we built a unicast response packet { debugf("Unicast Response: %d Question%s, %d Answer%s, %d Additional%s to %#-15a:%d on %p/%ld", m->omsg.h.numQuestions, m->omsg.h.numQuestions == 1 ? "" : "s", m->omsg.h.numAnswers, m->omsg.h.numAnswers == 1 ? "" : "s", m->omsg.h.numAdditionals, m->omsg.h.numAdditionals == 1 ? "" : "s", srcaddr, mDNSVal16(srcport), InterfaceID, srcaddr->type); mDNSSendDNSMessage(m, &m->omsg, responseend, InterfaceID, mDNSNULL, srcaddr, srcport, mDNSNULL, mDNSNULL, mDNSfalse); } } #if 0 mDNSlocal mDNSBool TrustedSource(const mDNS *const m, const mDNSAddr *const srcaddr) { DNSServer *s; (void)m; // Unused (void)srcaddr; // Unused for (s = m->DNSServers; s; s = s->next) if (mDNSSameAddress(srcaddr, &s->addr)) return(mDNStrue); return(mDNSfalse); } #endif struct UDPSocket_struct { mDNSIPPort port; // MUST BE FIRST FIELD -- mDNSCoreReceive expects every UDPSocket_struct to begin with mDNSIPPort port }; mDNSlocal DNSQuestion *ExpectingUnicastResponseForQuestion(const mDNS *const m, const mDNSIPPort port, const mDNSOpaque16 id, const DNSQuestion *const question, mDNSBool tcp) { DNSQuestion *q; for (q = m->Questions; q; q=q->next) { if (!tcp && !q->LocalSocket) continue; if (mDNSSameIPPort(tcp ? q->tcpSrcPort : q->LocalSocket->port, port) && mDNSSameOpaque16(q->TargetQID, id) && q->qtype == question->qtype && q->qclass == question->qclass && q->qnamehash == question->qnamehash && SameDomainName(&q->qname, &question->qname)) return(q); } return(mDNSNULL); } // This function is called when we receive a unicast response. This could be the case of a unicast response from the // DNS server or a response to the QU query. Hence, the cache record's InterfaceId can be both NULL or non-NULL (QU case) mDNSlocal DNSQuestion *ExpectingUnicastResponseForRecord(mDNS *const m, const mDNSAddr *const srcaddr, const mDNSBool SrcLocal, const mDNSIPPort port, const mDNSOpaque16 id, const CacheRecord *const rr, mDNSBool tcp) { DNSQuestion *q; (void)id; (void)srcaddr; for (q = m->Questions; q; q=q->next) { if (!q->DuplicateOf && ResourceRecordAnswersUnicastResponse(&rr->resrec, q)) { if (!mDNSOpaque16IsZero(q->TargetQID)) { debugf("ExpectingUnicastResponseForRecord msg->h.id %d q->TargetQID %d for %s", mDNSVal16(id), mDNSVal16(q->TargetQID), CRDisplayString(m, rr)); if (mDNSSameOpaque16(q->TargetQID, id)) { mDNSIPPort srcp; if (!tcp) { srcp = q->LocalSocket ? q->LocalSocket->port : zeroIPPort; } else { srcp = q->tcpSrcPort; } if (mDNSSameIPPort(srcp, port)) return(q); // if (mDNSSameAddress(srcaddr, &q->Target)) return(mDNStrue); // if (q->LongLived && mDNSSameAddress(srcaddr, &q->servAddr)) return(mDNStrue); Shouldn't need this now that we have LLQType checking // if (TrustedSource(m, srcaddr)) return(mDNStrue); LogInfo("WARNING: Ignoring suspect uDNS response for %##s (%s) [q->Target %#a:%d] from %#a:%d %s", q->qname.c, DNSTypeName(q->qtype), &q->Target, mDNSVal16(srcp), srcaddr, mDNSVal16(port), CRDisplayString(m, rr)); return(mDNSNULL); } } else { if (SrcLocal && q->ExpectUnicastResp && (mDNSu32)(m->timenow - q->ExpectUnicastResp) < (mDNSu32)(mDNSPlatformOneSecond*2)) return(q); } } } return(mDNSNULL); } // Certain data types need more space for in-memory storage than their in-packet rdlength would imply // Currently this applies only to rdata types containing more than one domainname, // or types where the domainname is not the last item in the structure. mDNSlocal mDNSu16 GetRDLengthMem(const ResourceRecord *const rr) { switch (rr->rrtype) { case kDNSType_SOA: return sizeof(rdataSOA); case kDNSType_RP: return sizeof(rdataRP); case kDNSType_PX: return sizeof(rdataPX); default: return rr->rdlength; } } mDNSexport CacheRecord *CreateNewCacheEntry(mDNS *const m, const mDNSu32 slot, CacheGroup *cg, mDNSs32 delay, mDNSBool Add, const mDNSAddr *sourceAddress) { CacheRecord *rr = mDNSNULL; mDNSu16 RDLength = GetRDLengthMem(&m->rec.r.resrec); if (!m->rec.r.resrec.InterfaceID) debugf("CreateNewCacheEntry %s", CRDisplayString(m, &m->rec.r)); //if (RDLength > InlineCacheRDSize) // LogInfo("Rdata len %4d > InlineCacheRDSize %d %s", RDLength, InlineCacheRDSize, CRDisplayString(m, &m->rec.r)); if (!cg) cg = GetCacheGroup(m, slot, &m->rec.r.resrec); // If we don't have a CacheGroup for this name, make one now if (cg) rr = GetCacheRecord(m, cg, RDLength); // Make a cache record, being careful not to recycle cg if (!rr) NoCacheAnswer(m, &m->rec.r); else { RData *saveptr = rr->resrec.rdata; // Save the rr->resrec.rdata pointer *rr = m->rec.r; // Block copy the CacheRecord object rr->resrec.rdata = saveptr; // Restore rr->resrec.rdata after the structure assignment rr->resrec.name = cg->name; // And set rr->resrec.name to point into our CacheGroup header // We need to add the anonymous info before we call CacheRecordAdd so that // if it finds a matching question with this record, it bumps up the counters like // CurrentAnswers etc. Otherwise, when a cache entry gets removed, CacheRecordRmv // will complain. if (m->rec.r.resrec.AnonInfo) { rr->resrec.AnonInfo = m->rec.r.resrec.AnonInfo; m->rec.r.resrec.AnonInfo = mDNSNULL; } rr->DelayDelivery = delay; // If this is an oversized record with external storage allocated, copy rdata to external storage if (rr->resrec.rdata == (RData*)&rr->smallrdatastorage && RDLength > InlineCacheRDSize) LogMsg("rr->resrec.rdata == &rr->rdatastorage but length > InlineCacheRDSize %##s", m->rec.r.resrec.name->c); else if (rr->resrec.rdata != (RData*)&rr->smallrdatastorage && RDLength <= InlineCacheRDSize) LogMsg("rr->resrec.rdata != &rr->rdatastorage but length <= InlineCacheRDSize %##s", m->rec.r.resrec.name->c); if (RDLength > InlineCacheRDSize) mDNSPlatformMemCopy(rr->resrec.rdata, m->rec.r.resrec.rdata, sizeofRDataHeader + RDLength); rr->next = mDNSNULL; // Clear 'next' pointer rr->nsec = mDNSNULL; rr->soa = mDNSNULL; if (sourceAddress) rr->sourceAddress = *sourceAddress; if (!rr->resrec.InterfaceID) { m->rrcache_totalused_unicast += rr->resrec.rdlength; if (DNSSECRecordType(rr->resrec.rrtype)) BumpDNSSECStats(m, kStatsActionIncrement, kStatsTypeMemoryUsage, rr->resrec.rdlength); } if (Add) { *(cg->rrcache_tail) = rr; // Append this record to tail of cache slot list cg->rrcache_tail = &(rr->next); // Advance tail pointer CacheRecordAdd(m, rr); // CacheRecordAdd calls SetNextCacheCheckTimeForRecord(m, rr); for us } else { // Can't use the "cg->name" if we are not adding to the cache as the // CacheGroup may be released anytime if it is empty domainname *name = mDNSPlatformMemAllocate(DomainNameLength(cg->name)); if (name) { AssignDomainName(name, cg->name); rr->resrec.name = name; } else { ReleaseCacheRecord(m, rr); NoCacheAnswer(m, &m->rec.r); rr = mDNSNULL; } } } return(rr); } mDNSlocal void RefreshCacheRecord(mDNS *const m, CacheRecord *rr, mDNSu32 ttl) { rr->TimeRcvd = m->timenow; rr->resrec.rroriginalttl = ttl; rr->UnansweredQueries = 0; SetNextCacheCheckTimeForRecord(m, rr); } mDNSexport void GrantCacheExtensions(mDNS *const m, DNSQuestion *q, mDNSu32 lease) { CacheRecord *rr; CacheGroup *cg = CacheGroupForName(m, q->qnamehash, &q->qname); for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) if (rr->CRActiveQuestion == q) { //LogInfo("GrantCacheExtensions: new lease %d / %s", lease, CRDisplayString(m, rr)); RefreshCacheRecord(m, rr, lease); } } mDNSlocal mDNSu32 GetEffectiveTTL(const uDNS_LLQType LLQType, mDNSu32 ttl) // TTL in seconds { if (LLQType == uDNS_LLQ_Entire) ttl = kLLQ_DefLease; else if (LLQType == uDNS_LLQ_Events) { // If the TTL is -1 for uDNS LLQ event packet, that means "remove" if (ttl == 0xFFFFFFFF) ttl = 0; else ttl = kLLQ_DefLease; } else // else not LLQ (standard uDNS response) { // The TTL is already capped to a maximum value in GetLargeResourceRecord, but just to be extra safe we // also do this check here to make sure we can't get overflow below when we add a quarter to the TTL if (ttl > 0x60000000UL / mDNSPlatformOneSecond) ttl = 0x60000000UL / mDNSPlatformOneSecond; ttl = RRAdjustTTL(ttl); // For mDNS, TTL zero means "delete this record" // For uDNS, TTL zero means: this data is true at this moment, but don't cache it. // For the sake of network efficiency, we impose a minimum effective TTL of 15 seconds. // This means that we'll do our 80, 85, 90, 95% queries at 12.00, 12.75, 13.50, 14.25 seconds // respectively, and then if we get no response, delete the record from the cache at 15 seconds. // This gives the server up to three seconds to respond between when we send our 80% query at 12 seconds // and when we delete the record at 15 seconds. Allowing cache lifetimes less than 15 seconds would // (with the current code) result in the server having even less than three seconds to respond // before we deleted the record and reported a "remove" event to any active questions. // Furthermore, with the current code, if we were to allow a TTL of less than 2 seconds // then things really break (e.g. we end up making a negative cache entry). // In the future we may want to revisit this and consider properly supporting non-cached (TTL=0) uDNS answers. if (ttl < 15) ttl = 15; } return ttl; } // When the response does not match the question directly, we still want to cache them sometimes. The current response is // in m->rec. mDNSlocal mDNSBool IsResponseAcceptable(mDNS *const m, const CacheRecord *crlist, DNSQuestion *q, mDNSBool *nseclist) { CacheRecord *const newcr = &m->rec.r; ResourceRecord *rr = &newcr->resrec; const CacheRecord *cr; *nseclist = mDNSfalse; for (cr = crlist; cr != (CacheRecord*)1; cr = cr->NextInCFList) { domainname *target = GetRRDomainNameTarget(&cr->resrec); // When we issue a query for A record, the response might contain both a CNAME and A records. Only the CNAME would // match the question and we already created a cache entry in the previous pass of this loop. Now when we process // the A record, it does not match the question because the record name here is the CNAME. Hence we try to // match with the previous records to make it an AcceptableResponse. We have to be careful about setting the // DNSServer value that we got in the previous pass. This can happen for other record types like SRV also. if (target && cr->resrec.rdatahash == rr->namehash && SameDomainName(target, rr->name)) { LogInfo("IsResponseAcceptable: Found a matching entry for %##s in the CacheFlushRecords %s", rr->name->c, CRDisplayString(m, cr)); return (mDNStrue); } } // Either the question requires validation or we are validating a response with DNSSEC in which case // we need to accept the RRSIGs also so that we can validate the response. It is also possible that // we receive NSECs for our query which does not match the qname and we need to cache in that case // too. nseclist is set if they have to be cached as part of the negative cache record. if (q && DNSSECQuestion(q)) { mDNSBool same = SameDomainName(&q->qname, rr->name); if (same && (q->qtype == rr->rrtype || rr->rrtype == kDNSType_CNAME)) { LogInfo("IsResponseAcceptable: Accepting, same name and qtype %s, CR %s", DNSTypeName(q->qtype), CRDisplayString(m, newcr)); return mDNStrue; } // We cache RRSIGS if it covers the question type or NSEC. If it covers a NSEC, // "nseclist" is set if (rr->rrtype == kDNSType_RRSIG) { RDataBody2 *const rdb = (RDataBody2 *)newcr->smallrdatastorage.data; rdataRRSig *rrsig = &rdb->rrsig; mDNSu16 typeCovered = swap16(rrsig->typeCovered); // Note the ordering. If we are looking up the NSEC record, then the RRSIG's typeCovered // would match the qtype and they are cached normally as they are not used to prove the // non-existence of any name. In that case, it is like any other normal dnssec validation // and hence nseclist should not be set. if (same && ((typeCovered == q->qtype) || (typeCovered == kDNSType_CNAME))) { LogInfo("IsResponseAcceptable: Accepting RRSIG %s matches question type %s", CRDisplayString(m, newcr), DNSTypeName(q->qtype)); return mDNStrue; } else if (typeCovered == kDNSType_NSEC || typeCovered == kDNSType_NSEC3) { LogInfo("IsResponseAcceptable: Accepting RRSIG %s matches %s type (nseclist = 1)", CRDisplayString(m, newcr), DNSTypeName(typeCovered)); *nseclist = mDNStrue; return mDNStrue; } else if (typeCovered == kDNSType_SOA) { LogInfo("IsResponseAcceptable: Accepting RRSIG %s matches SOA type (nseclist = 1)", CRDisplayString(m, newcr)); *nseclist = mDNStrue; return mDNStrue; } else return mDNSfalse; } if (rr->rrtype == kDNSType_NSEC) { if (!UNICAST_NSEC(rr)) { LogMsg("IsResponseAcceptable: ERROR!! Not a unicast NSEC %s", CRDisplayString(m, newcr)); return mDNSfalse; } LogInfo("IsResponseAcceptable: Accepting NSEC %s (nseclist = 1)", CRDisplayString(m, newcr)); *nseclist = mDNStrue; return mDNStrue; } if (rr->rrtype == kDNSType_SOA) { LogInfo("IsResponseAcceptable: Accepting SOA %s (nseclist = 1)", CRDisplayString(m, newcr)); *nseclist = mDNStrue; return mDNStrue; } else if (rr->rrtype == kDNSType_NSEC3) { LogInfo("IsResponseAcceptable: Accepting NSEC3 %s (nseclist = 1)", CRDisplayString(m, newcr)); *nseclist = mDNStrue; return mDNStrue; } } return mDNSfalse; } mDNSlocal void FreeNSECRecords(mDNS *const m, CacheRecord *NSECRecords) { CacheRecord *rp, *next; for (rp = NSECRecords; rp; rp = next) { next = rp->next; ReleaseCacheRecord(m, rp); } } // If we received zero DNSSEC records even when the DO/EDNS0 bit was set, we need to provide this // information to ValidatingResponse question to indicate the DNSSEC status to the application mDNSlocal void mDNSCoreReceiveNoDNSSECAnswers(mDNS *const m, const DNSMessage *const response, const mDNSu8 *end, const mDNSAddr *dstaddr, mDNSIPPort dstport, const mDNSInterfaceID InterfaceID) { int i; const mDNSu8 *ptr = response->data; for (i = 0; i < response->h.numQuestions && ptr && ptr < end; i++) { DNSQuestion pktq; DNSQuestion *qptr = mDNSNULL; ptr = getQuestion(response, ptr, end, InterfaceID, &pktq); if (ptr && (qptr = ExpectingUnicastResponseForQuestion(m, dstport, response->h.id, &pktq, !dstaddr)) && qptr->ValidatingResponse) { DNSQuestion *next, *q; if (qptr->DuplicateOf) LogMsg("mDNSCoreReceiveNoDNSSECAnswers: ERROR!! qptr %##s (%s) Duplicate question matching response", qptr->qname.c, DNSTypeName(qptr->qtype)); // Be careful to call the callback for duplicate questions first and then the original // question. If we called the callback on the original question, it could stop and // a duplicate question would become the original question. mDNS_DropLockBeforeCallback(); // Allow client (and us) to legally make mDNS API calls for (q = qptr->next ; q && q != m->NewQuestions; q = next) { next = q->next; if (q->DuplicateOf == qptr) { if (q->ValidatingResponse) LogInfo("mDNSCoreReceiveNoDNSSECAnswers: qptr %##s (%s) Duplicate question found", q->qname.c, DNSTypeName(q->qtype)); else LogMsg("mDNSCoreReceiveNoDNSSECAnswers: ERROR!! qptr %##s (%s) Duplicate question not ValidatingResponse", q->qname.c, DNSTypeName(q->qtype)); if (q->QuestionCallback) q->QuestionCallback(m, q, mDNSNULL, QC_nodnssec); } } if (qptr->QuestionCallback) qptr->QuestionCallback(m, qptr, mDNSNULL, QC_nodnssec); mDNS_ReclaimLockAfterCallback(); // Decrement mDNS_reentrancy to block mDNS API calls again } } } mDNSlocal void mDNSCoreReceiveNoUnicastAnswers(mDNS *const m, const DNSMessage *const response, const mDNSu8 *end, const mDNSAddr *dstaddr, mDNSIPPort dstport, const mDNSInterfaceID InterfaceID, uDNS_LLQType LLQType, mDNSu8 rcode, CacheRecord *NSECRecords) { int i; const mDNSu8 *ptr = response->data; CacheRecord *SOARecord = mDNSNULL; for (i = 0; i < response->h.numQuestions && ptr && ptr < end; i++) { DNSQuestion q; DNSQuestion *qptr = mDNSNULL; ptr = getQuestion(response, ptr, end, InterfaceID, &q); if (ptr && (qptr = ExpectingUnicastResponseForQuestion(m, dstport, response->h.id, &q, !dstaddr))) { CacheRecord *rr, *neg = mDNSNULL; CacheGroup *cg = CacheGroupForName(m, q.qnamehash, &q.qname); for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) if (SameNameRecordAnswersQuestion(&rr->resrec, qptr)) { // 1. If we got a fresh answer to this query, then don't need to generate a negative entry if (RRExpireTime(rr) - m->timenow > 0) break; // 2. If we already had a negative entry, keep track of it so we can resurrect it instead of creating a new one if (rr->resrec.RecordType == kDNSRecordTypePacketNegative) neg = rr; } // When we're doing parallel unicast and multicast queries for dot-local names (for supporting Microsoft // Active Directory sites) we don't want to waste memory making negative cache entries for all the unicast answers. // Otherwise we just fill up our cache with negative entries for just about every single multicast name we ever look up // (since the Microsoft Active Directory server is going to assert that pretty much every single multicast name doesn't exist). // This is not only a waste of memory, but there's also the problem of those negative entries confusing us later -- e.g. we // suppress sending our mDNS query packet because we think we already have a valid (negative) answer to that query in our cache. // The one exception is that we *DO* want to make a negative cache entry for "local. SOA", for the (common) case where we're // *not* on a Microsoft Active Directory network, and there is no authoritative server for "local". Note that this is not // in conflict with the mDNS spec, because that spec says, "Multicast DNS Zones have no SOA record," so it's okay to cache // negative answers for "local. SOA" from a uDNS server, because the mDNS spec already says that such records do not exist :-) // // By suppressing negative responses, it might take longer to timeout a .local question as it might be expecting a // response e.g., we deliver a positive "A" response and suppress negative "AAAA" response and the upper layer may // be waiting longer to get the AAAA response before returning the "A" response to the application. To handle this // case without creating the negative cache entries, we generate a negative response and let the layer above us // do the appropriate thing. This negative response is also needed for appending new search domains. if (!InterfaceID && q.qtype != kDNSType_SOA && IsLocalDomain(&q.qname)) { if (!rr) { LogInfo("mDNSCoreReceiveNoUnicastAnswers: Generate negative response for %##s (%s)", q.qname.c, DNSTypeName(q.qtype)); m->CurrentQuestion = qptr; // We are not creating a cache record in this case, we need to pass back // the error we got so that the proxy code can return the right one to // the application if (qptr->ProxyQuestion) qptr->responseFlags = response->h.flags; GenerateNegativeResponse(m, mDNSInterface_Any, QC_forceresponse); m->CurrentQuestion = mDNSNULL; } else { LogInfo("mDNSCoreReceiveNoUnicastAnswers: Skipping check and not creating a negative cache entry for %##s (%s)", q.qname.c, DNSTypeName(q.qtype)); } } else { if (!rr) { // We start off assuming a negative caching TTL of 60 seconds // but then look to see if we can find an SOA authority record to tell us a better value we should be using mDNSu32 negttl = 60; int repeat = 0; const domainname *name = &q.qname; mDNSu32 hash = q.qnamehash; // Special case for our special Microsoft Active Directory "local SOA" check. // Some cheap home gateways don't include an SOA record in the authority section when // they send negative responses, so we don't know how long to cache the negative result. // Because we don't want to keep hitting the root name servers with our query to find // if we're on a network using Microsoft Active Directory using "local" as a private // internal top-level domain, we make sure to cache the negative result for at least one day. if (q.qtype == kDNSType_SOA && SameDomainName(&q.qname, &localdomain)) negttl = 60 * 60 * 24; // If we're going to make (or update) a negative entry, then look for the appropriate TTL from the SOA record if (response->h.numAuthorities && (ptr = LocateAuthorities(response, end)) != mDNSNULL) { ptr = GetLargeResourceRecord(m, response, ptr, end, InterfaceID, kDNSRecordTypePacketAuth, &m->rec); if (ptr && m->rec.r.resrec.RecordType != kDNSRecordTypePacketNegative && m->rec.r.resrec.rrtype == kDNSType_SOA) { CacheGroup *cgSOA = CacheGroupForRecord(m, &m->rec.r.resrec); const rdataSOA *const soa = (const rdataSOA *)m->rec.r.resrec.rdata->u.data; mDNSu32 ttl_s = soa->min; // We use the lesser of the SOA.MIN field and the SOA record's TTL, *except* // for the SOA record for ".", where the record is reported as non-cacheable // (TTL zero) for some reason, so in this case we just take the SOA record's TTL as-is if (ttl_s > m->rec.r.resrec.rroriginalttl && m->rec.r.resrec.name->c[0]) ttl_s = m->rec.r.resrec.rroriginalttl; if (negttl < ttl_s) negttl = ttl_s; // Create the SOA record as we may have to return this to the questions // that we are acting as a proxy for currently or in the future. SOARecord = CreateNewCacheEntry(m, HashSlotFromNameHash(m->rec.r.resrec.namehash), cgSOA, 1, mDNSfalse, mDNSNULL); // Special check for SOA queries: If we queried for a.b.c.d.com, and got no answer, // with an Authority Section SOA record for d.com, then this is a hint that the authority // is d.com, and consequently SOA records b.c.d.com and c.d.com don't exist either. // To do this we set the repeat count so the while loop below will make a series of negative cache entries for us // // For ProxyQuestions, we don't do this as we need to create additional SOA records to cache them // along with the negative cache record. For simplicity, we don't create the additional records. if (!qptr->ProxyQuestion && q.qtype == kDNSType_SOA) { int qcount = CountLabels(&q.qname); int scount = CountLabels(m->rec.r.resrec.name); if (qcount - 1 > scount) if (SameDomainName(SkipLeadingLabels(&q.qname, qcount - scount), m->rec.r.resrec.name)) repeat = qcount - 1 - scount; } } m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it } // If we already had a negative entry in the cache, then we double our existing negative TTL. This is to avoid // the case where the record doesn't exist (e.g. particularly for things like our lb._dns-sd._udp. query), // and the server returns no SOA record (or an SOA record with a small MIN TTL) so we assume a TTL // of 60 seconds, and we end up polling the server every minute for a record that doesn't exist. // With this fix in place, when this happens, we double the effective TTL each time (up to one hour), // so that we back off our polling rate and don't keep hitting the server continually. if (neg) { if (negttl < neg->resrec.rroriginalttl * 2) negttl = neg->resrec.rroriginalttl * 2; if (negttl > 3600) negttl = 3600; } negttl = GetEffectiveTTL(LLQType, negttl); // Add 25% grace period if necessary // If we already had a negative cache entry just update it, else make one or more new negative cache entries. if (neg) { LogInfo("mDNSCoreReceiveNoUnicastAnswers: Renewing negative TTL from %d to %d %s", neg->resrec.rroriginalttl, negttl, CRDisplayString(m, neg)); RefreshCacheRecord(m, neg, negttl); // When we created the cache for the first time and answered the question, the question's // interval was set to MaxQuestionInterval. If the cache is about to expire and we are resending // the queries, the interval should still be at MaxQuestionInterval. If the query is being // restarted (setting it to InitialQuestionInterval) for other reasons e.g., wakeup, // we should reset its question interval here to MaxQuestionInterval. ResetQuestionState(m, qptr); if (DNSSECQuestion(qptr)) neg->CRDNSSECQuestion = 1; // Update the NSEC records again. // TBD: Need to purge and revalidate if the cached NSECS and the new set are not same. if (NSECRecords) { if (!AddNSECSForCacheRecord(m, NSECRecords, neg, rcode)) { // We might just have an SOA record for zones that are not signed and hence don't log // this as an error LogInfo("mDNSCoreReceiveNoUnicastAnswers: AddNSECSForCacheRecord failed to add NSEC for negcr %s during refresh", CRDisplayString(m, neg)); FreeNSECRecords(m, NSECRecords); neg->CRDNSSECQuestion = 0; } NSECRecords = mDNSNULL; } if (SOARecord) { if (neg->soa) ReleaseCacheRecord(m, neg->soa); neg->soa = SOARecord; SOARecord = mDNSNULL; } } else while (1) { CacheRecord *negcr; debugf("mDNSCoreReceiveNoUnicastAnswers making negative cache entry TTL %d for %##s (%s)", negttl, name->c, DNSTypeName(q.qtype)); MakeNegativeCacheRecord(m, &m->rec.r, name, hash, q.qtype, q.qclass, negttl, mDNSInterface_Any, qptr->qDNSServer); m->rec.r.responseFlags = response->h.flags; // We create SOA records above which might create new cache groups. Earlier // in the function we looked up the cache group for the name and it could have // been NULL. If we pass NULL cg to new cache entries that we create below, // it will create additional cache groups for the same name. To avoid that, // look up the cache group again to re-initialize cg again. cg = CacheGroupForName(m, hash, name); if (NSECRecords && DNSSECQuestion(qptr)) { // Create the cache entry with delay and then add the NSEC records // to it and add it immediately. negcr = CreateNewCacheEntry(m, HashSlotFromNameHash(hash), cg, 1, mDNStrue, mDNSNULL); if (negcr) { negcr->CRDNSSECQuestion = 0; if (!AddNSECSForCacheRecord(m, NSECRecords, negcr, rcode)) { LogInfo("mDNSCoreReceiveNoUnicastAnswers: AddNSECSForCacheRecord failed to add NSEC for negcr %s", CRDisplayString(m, negcr)); FreeNSECRecords(m, NSECRecords); } else { negcr->CRDNSSECQuestion = 1; LogInfo("mDNSCoreReceiveNoUnicastAnswers: AddNSECSForCacheRecord added neg NSEC for %s", CRDisplayString(m, negcr)); } NSECRecords = mDNSNULL; negcr->DelayDelivery = 0; CacheRecordDeferredAdd(m, negcr); } m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it break; } else { // Need to add with a delay so that we can tag the SOA record negcr = CreateNewCacheEntry(m, HashSlotFromNameHash(hash), cg, 1, mDNStrue, mDNSNULL); if (negcr) { negcr->CRDNSSECQuestion = 0; if (DNSSECQuestion(qptr)) negcr->CRDNSSECQuestion = 1; negcr->DelayDelivery = 0; if (SOARecord) { if (negcr->soa) ReleaseCacheRecord(m, negcr->soa); negcr->soa = SOARecord; SOARecord = mDNSNULL; } CacheRecordDeferredAdd(m, negcr); } } m->rec.r.responseFlags = zeroID; m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it if (!repeat) break; repeat--; name = (const domainname *)(name->c + 1 + name->c[0]); hash = DomainNameHashValue(name); } } } } } if (NSECRecords) { LogInfo("mDNSCoreReceiveNoUnicastAnswers: NSECRecords not used"); FreeNSECRecords(m, NSECRecords); } if (SOARecord) { LogInfo("mDNSCoreReceiveNoUnicastAnswers: SOARecord not used"); ReleaseCacheRecord(m, SOARecord); } } mDNSlocal void mDNSCorePrintStoredProxyRecords(mDNS *const m) { AuthRecord *rrPtr = mDNSNULL; LogSPS("Stored Proxy records :"); for (rrPtr = m->SPSRRSet; rrPtr; rrPtr = rrPtr->next) { LogSPS("%s", ARDisplayString(m, rrPtr)); } } mDNSlocal mDNSBool mDNSCoreRegisteredProxyRecord(mDNS *const m, AuthRecord *rr) { AuthRecord *rrPtr = mDNSNULL; for (rrPtr = m->SPSRRSet; rrPtr; rrPtr = rrPtr->next) { if (IdenticalResourceRecord(&rrPtr->resrec, &rr->resrec)) { LogSPS("mDNSCoreRegisteredProxyRecord: Ignoring packet registered with sleep proxy : %s ", ARDisplayString(m, rr)); return mDNStrue; } } mDNSCorePrintStoredProxyRecords(m); return mDNSfalse; } mDNSlocal CacheRecord* mDNSCoreReceiveCacheCheck(mDNS *const m, const DNSMessage *const response, uDNS_LLQType LLQType, const mDNSu32 slot, CacheGroup *cg, DNSQuestion *unicastQuestion, CacheRecord ***cfp, CacheRecord **NSECCachePtr, mDNSInterfaceID InterfaceID) { CacheRecord *rr; CacheRecord **cflocal = *cfp; for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) { mDNSBool match; // Resource record received via unicast, the resGroupID should match ? if (!InterfaceID) { mDNSu16 id1 = (rr->resrec.rDNSServer ? rr->resrec.rDNSServer->resGroupID : 0); mDNSu16 id2 = (m->rec.r.resrec.rDNSServer ? m->rec.r.resrec.rDNSServer->resGroupID : 0); match = (id1 == id2); } else match = (rr->resrec.InterfaceID == InterfaceID); // If we found this exact resource record, refresh its TTL if (match && IdenticalSameNameRecord(&m->rec.r.resrec, &rr->resrec)) { if (m->rec.r.resrec.rdlength > InlineCacheRDSize) verbosedebugf("mDNSCoreReceiveCacheCheck: Found record size %5d interface %p already in cache: %s", m->rec.r.resrec.rdlength, InterfaceID, CRDisplayString(m, &m->rec.r)); if (m->rec.r.resrec.RecordType & kDNSRecordTypePacketUniqueMask) { // If this packet record has the kDNSClass_UniqueRRSet flag set, then add it to our cache flushing list if (rr->NextInCFList == mDNSNULL && *cfp != &rr->NextInCFList && LLQType != uDNS_LLQ_Events) { *cflocal = rr; cflocal = &rr->NextInCFList; *cflocal = (CacheRecord*)1; *cfp = &rr->NextInCFList; } // If this packet record is marked unique, and our previous cached copy was not, then fix it if (!(rr->resrec.RecordType & kDNSRecordTypePacketUniqueMask)) { DNSQuestion *q; for (q = m->Questions; q; q=q->next) { if (ResourceRecordAnswersQuestion(&rr->resrec, q)) q->UniqueAnswers++; } rr->resrec.RecordType = m->rec.r.resrec.RecordType; } } if (!SameRDataBody(&m->rec.r.resrec, &rr->resrec.rdata->u, SameDomainNameCS)) { // If the rdata of the packet record differs in name capitalization from the record in our cache // then mDNSPlatformMemSame will detect this. In this case, throw the old record away, so that clients get // a 'remove' event for the record with the old capitalization, and then an 'add' event for the new one. // mDNS -F returns the same domain multiple times with different casing rr->resrec.rroriginalttl = 0; rr->TimeRcvd = m->timenow; rr->UnansweredQueries = MaxUnansweredQueries; SetNextCacheCheckTimeForRecord(m, rr); LogInfo("mDNSCoreReceiveCacheCheck: Discarding due to domainname case change old: %s", CRDisplayString(m, rr)); LogInfo("mDNSCoreReceiveCacheCheck: Discarding due to domainname case change new: %s", CRDisplayString(m, &m->rec.r)); LogInfo("mDNSCoreReceiveCacheCheck: Discarding due to domainname case change in %d slot %3d in %d %d", NextCacheCheckEvent(rr) - m->timenow, slot, m->rrcache_nextcheck[slot] - m->timenow, m->NextCacheCheck - m->timenow); // DO NOT break out here -- we want to continue as if we never found it } else if (!IdenticalAnonInfo(m->rec.r.resrec.AnonInfo, rr->resrec.AnonInfo)) { // If the NSEC3 record changed, a few possibilities // // 1) the peer reinitialized e.g., after network change and still part of the // same set. // 2) the peer went to a different set but we did not see the goodbyes. If we just // update the nsec3 record, it would be incorrect. Flush the cache so that we // can deliver a RMV followed by ADD. // 3) if the peer is ourselves and we see the goodbye when moving to a different set // and so we flush the cache and create a new cache record with the new set information. // Now we move back to the original set. In this case, we can't just update the // NSEC3 record alone. We need to flush so that we can deliver an RMV followed by ADD // when we create the new cache entry. // // Note: For case (1), we could avoid flushing the cache but we can't tell the difference // from the other cases. rr->resrec.rroriginalttl = 0; rr->TimeRcvd = m->timenow; rr->UnansweredQueries = MaxUnansweredQueries; SetNextCacheCheckTimeForRecord(m, rr); LogInfo("mDNSCoreReceiveCacheCheck: AnonInfo changed for %s", CRDisplayString(m, rr)); // DO NOT break out here -- we want to continue as if we never found it. When we return // from this function, we will create a new cache entry with the new NSEC3 record } else if (m->rec.r.resrec.rroriginalttl > 0) { DNSQuestion *q; m->mDNSStats.CacheRefreshed++; if (rr->resrec.rroriginalttl == 0) debugf("uDNS rescuing %s", CRDisplayString(m, rr)); RefreshCacheRecord(m, rr, m->rec.r.resrec.rroriginalttl); rr->responseFlags = response->h.flags; // If we may have NSEC records returned with the answer (which we don't know yet as it // has not been processed), we need to cache them along with the first cache // record in the list that answers the question so that it can be used for validation // later. The "type" check below is to make sure that we cache on the cache record // that would answer the question. It is possible that we might cache additional things // e.g., MX question might cache A records also, and we want to cache the NSEC on // the record that answers the question. if (response->h.numAnswers && unicastQuestion && unicastQuestion->qtype == rr->resrec.rrtype && !(*NSECCachePtr)) { LogInfo("mDNSCoreReceiveCacheCheck: rescuing RR %s", CRDisplayString(m, rr)); *NSECCachePtr = rr; } // We have to reset the question interval to MaxQuestionInterval so that we don't keep // polling the network once we get a valid response back. For the first time when a new // cache entry is created, AnswerCurrentQuestionWithResourceRecord does that. // Subsequently, if we reissue questions from within the mDNSResponder e.g., DNS server // configuration changed, without flushing the cache, we reset the question interval here. // Currently, we do this for for both multicast and unicast questions as long as the record // type is unique. For unicast, resource record is always unique and for multicast it is // true for records like A etc. but not for PTR. if (rr->resrec.RecordType & kDNSRecordTypePacketUniqueMask) { for (q = m->Questions; q; q=q->next) { if (!q->DuplicateOf && !q->LongLived && ActiveQuestion(q) && ResourceRecordAnswersQuestion(&rr->resrec, q)) { ResetQuestionState(m, q); debugf("mDNSCoreReceiveCacheCheck: Set MaxQuestionInterval for %p %##s (%s)", q, q->qname.c, DNSTypeName(q->qtype)); break; // Why break here? Aren't there other questions we might want to look at?-- SC July 2010 } } } break; } else { // If the packet TTL is zero, that means we're deleting this record. // To give other hosts on the network a chance to protest, we push the deletion // out one second into the future. Also, we set UnansweredQueries to MaxUnansweredQueries. // Otherwise, we'll do final queries for this record at 80% and 90% of its apparent // lifetime (800ms and 900ms from now) which is a pointless waste of network bandwidth. // If record's current expiry time is more than a second from now, we set it to expire in one second. // If the record is already going to expire in less than one second anyway, we leave it alone -- // we don't want to let the goodbye packet *extend* the record's lifetime in our cache. debugf("DE for %s", CRDisplayString(m, rr)); if (RRExpireTime(rr) - m->timenow > mDNSPlatformOneSecond) { rr->resrec.rroriginalttl = 1; rr->TimeRcvd = m->timenow; rr->UnansweredQueries = MaxUnansweredQueries; SetNextCacheCheckTimeForRecord(m, rr); } break; } } } return rr; } mDNSlocal void mDNSParseNSEC3Records(mDNS *const m, const DNSMessage *const response, const mDNSu8 *end, const mDNSInterfaceID InterfaceID, CacheRecord **NSEC3Records) { const mDNSu8 *ptr; CacheRecord *rr; int i; if (!response->h.numAuthorities) return; ptr = LocateAuthorities(response, end); if (!ptr) { LogInfo("mDNSParseNSEC3Records: ERROR can't locate authorities"); return; } for (i = 0; i < response->h.numAuthorities && ptr && ptr < end; i++) { CacheGroup *cg; ptr = GetLargeResourceRecord(m, response, ptr, end, InterfaceID, kDNSRecordTypePacketAuth, &m->rec); if (!ptr || m->rec.r.resrec.RecordType == kDNSRecordTypePacketNegative || m->rec.r.resrec.rrtype != kDNSType_NSEC3) { debugf("mDNSParseNSEC3Records: ptr %p, Record %s, ignoring", ptr, CRDisplayString(m, &m->rec.r)); m->rec.r.resrec.RecordType = 0; continue; } cg = CacheGroupForRecord(m, &m->rec.r.resrec); // Create the cache entry but don't add it to the cache it. We need // to cache this along with the main cache record. rr = CreateNewCacheEntry(m, HashSlotFromNameHash(m->rec.r.resrec.namehash), cg, 0, mDNSfalse, mDNSNULL); if (rr) { debugf("mDNSParseNSEC3Records: %s", CRDisplayString(m, rr)); *NSEC3Records = rr; NSEC3Records = &rr->next; } m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it } } mDNSlocal void mDNSCoreResetRecord(mDNS *const m) { m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it if (m->rec.r.resrec.AnonInfo) { FreeAnonInfo(m->rec.r.resrec.AnonInfo); m->rec.r.resrec.AnonInfo = mDNSNULL; } } // Note: mDNSCoreReceiveResponse calls mDNS_Deregister_internal which can call a user callback, which may change // the record list and/or question list. // Any code walking either list must use the CurrentQuestion and/or CurrentRecord mechanism to protect against this. // InterfaceID non-NULL tells us the interface this multicast response was received on // InterfaceID NULL tells us this was a unicast response // dstaddr NULL tells us we received this over an outgoing TCP connection we made mDNSlocal void mDNSCoreReceiveResponse(mDNS *const m, const DNSMessage *const response, const mDNSu8 *end, const mDNSAddr *srcaddr, const mDNSIPPort srcport, const mDNSAddr *dstaddr, mDNSIPPort dstport, const mDNSInterfaceID InterfaceID) { int i; mDNSBool ResponseMCast = dstaddr && mDNSAddrIsDNSMulticast(dstaddr); mDNSBool ResponseSrcLocal = !srcaddr || mDNS_AddressIsLocalSubnet(m, InterfaceID, srcaddr); DNSQuestion *llqMatch = mDNSNULL; DNSQuestion *unicastQuestion = mDNSNULL; uDNS_LLQType LLQType = uDNS_recvLLQResponse(m, response, end, srcaddr, srcport, &llqMatch); // "(CacheRecord*)1" is a special (non-zero) end-of-list marker // We use this non-zero marker so that records in our CacheFlushRecords list will always have NextInCFList // set non-zero, and that tells GetCacheEntity() that they're not, at this moment, eligible for recycling. CacheRecord *CacheFlushRecords = (CacheRecord*)1; CacheRecord **cfp = &CacheFlushRecords; CacheRecord *NSECRecords = mDNSNULL; CacheRecord *NSECCachePtr = mDNSNULL; CacheRecord **nsecp = &NSECRecords; CacheRecord *McastNSEC3Records = mDNSNULL; mDNSBool nseclist; mDNSu8 rcode = '\0'; mDNSBool rrsigsCreated = mDNSfalse; mDNSBool DNSSECQuestion = mDNSfalse; NetworkInterfaceInfo *llintf = FirstIPv4LLInterfaceForID(m, InterfaceID); mDNSBool recordAcceptedInResponse = mDNSfalse; // Set if a record is accepted from a unicast mDNS response that answers an existing question. // All records in a DNS response packet are treated as equally valid statements of truth. If we want // to guard against spoof responses, then the only credible protection against that is cryptographic // security, e.g. DNSSEC., not worrying about which section in the spoof packet contained the record. int firstauthority = response->h.numAnswers; int firstadditional = firstauthority + response->h.numAuthorities; int totalrecords = firstadditional + response->h.numAdditionals; const mDNSu8 *ptr = response->data; DNSServer *uDNSServer = mDNSNULL; debugf("Received Response from %#-15a addressed to %#-15a on %p with " "%2d Question%s %2d Answer%s %2d Authorit%s %2d Additional%s %d bytes LLQType %d", srcaddr, dstaddr, InterfaceID, response->h.numQuestions, response->h.numQuestions == 1 ? ", " : "s,", response->h.numAnswers, response->h.numAnswers == 1 ? ", " : "s,", response->h.numAuthorities, response->h.numAuthorities == 1 ? "y, " : "ies,", response->h.numAdditionals, response->h.numAdditionals == 1 ? " " : "s", end - response->data, LLQType); #if AWD_METRICS if (mDNSSameIPPort(srcport, UnicastDNSPort)) { MetricsUpdateDNSResponseSize((mDNSu32)(end - (mDNSu8 *)response)); } #endif // According to RFC 2181 // When a DNS client receives a reply with TC // set, it should ignore that response, and query again, using a // mechanism, such as a TCP connection, that will permit larger replies. // It feels wrong to be throwing away data after the network went to all the trouble of delivering it to us, but // delivering some records of the RRSet first and then the remainder a couple of milliseconds later was causing // failures in our Microsoft Active Directory client, which expects to get the entire set of answers at once. // Can't bind to Active Directory // In addition, if the client immediately canceled its query after getting the initial partial response, then we'll // abort our TCP connection, and not complete the operation, and end up with an incomplete RRSet in our cache. // Next time there's a query for this RRSet we'll see answers in our cache, and assume we have the whole RRSet already, // and not even do the TCP query. // Accordingly, if we get a uDNS reply with kDNSFlag0_TC set, we bail out and wait for the TCP response containing the entire RRSet. if (!InterfaceID && (response->h.flags.b[0] & kDNSFlag0_TC)) return; if (LLQType == uDNS_LLQ_Ignore) return; // 1. We ignore questions (if any) in mDNS response packets // 2. If this is an LLQ response, we handle it much the same // 3. If we get a uDNS UDP response with the TC (truncated) bit set, then we can't treat this // answer as being the authoritative complete RRSet, and respond by deleting all other // matching cache records that don't appear in this packet. // Otherwise, this is a authoritative uDNS answer, so arrange for any stale records to be purged if (ResponseMCast || LLQType == uDNS_LLQ_Events || (response->h.flags.b[0] & kDNSFlag0_TC)) ptr = LocateAnswers(response, end); // Otherwise, for one-shot queries, any answers in our cache that are not also contained // in this response packet are immediately deemed to be invalid. else { mDNSBool failure, returnEarly; rcode = (mDNSu8)(response->h.flags.b[1] & kDNSFlag1_RC_Mask); failure = !(rcode == kDNSFlag1_RC_NoErr || rcode == kDNSFlag1_RC_NXDomain || rcode == kDNSFlag1_RC_NotAuth); returnEarly = mDNSfalse; // We could possibly combine this with the similar loop at the end of this function -- // instead of tagging cache records here and then rescuing them if we find them in the answer section, // we could instead use the "m->PktNum" mechanism to tag each cache record with the packet number in // which it was received (or refreshed), and then at the end if we find any cache records which // answer questions in this packet's question section, but which aren't tagged with this packet's // packet number, then we deduce they are old and delete them for (i = 0; i < response->h.numQuestions && ptr && ptr < end; i++) { DNSQuestion q, *qptr = mDNSNULL; ptr = getQuestion(response, ptr, end, InterfaceID, &q); if (ptr && (qptr = ExpectingUnicastResponseForQuestion(m, dstport, response->h.id, &q, !dstaddr))) { if (!failure) { CacheRecord *rr; // Remember the unicast question that we found, which we use to make caching // decisions later on in this function CacheGroup *cg = CacheGroupForName(m, q.qnamehash, &q.qname); if (!mDNSOpaque16IsZero(response->h.id)) { unicastQuestion = qptr; if (qptr->qDNSServer && DNSSECQuestion(qptr)) { LogInfo("mDNSCoreReceiveResponse: Setting aware for %##s (%s) on %#a", qptr->qname.c, DNSTypeName(qptr->qtype), &qptr->qDNSServer->addr); qptr->qDNSServer->DNSSECAware = mDNStrue; qptr->qDNSServer->req_DO = mDNStrue; } if (qptr->ValidatingResponse) DNSSECQuestion = mDNStrue; } for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) if (SameNameRecordAnswersQuestion(&rr->resrec, qptr)) { debugf("uDNS marking %p %##s (%s) %p %s", q.InterfaceID, q.qname.c, DNSTypeName(q.qtype), rr->resrec.InterfaceID, CRDisplayString(m, rr)); // Don't want to disturb rroriginalttl here, because code below might need it for the exponential backoff doubling algorithm rr->TimeRcvd = m->timenow - TicksTTL(rr) - 1; rr->UnansweredQueries = MaxUnansweredQueries; rr->CRDNSSECQuestion = 0; if (unicastQuestion && DNSSECQuestion(unicastQuestion)) { LogInfo("mDNSCoreReceiveResponse: CRDNSSECQuestion set for record %s, question %##s (%s)", CRDisplayString(m, rr), unicastQuestion->qname.c, DNSTypeName(unicastQuestion->qtype)); rr->CRDNSSECQuestion = 1; } } } else { if (qptr) { // If we recv any error from the DNSServer for a DNSSEC Query and if we know that the server // is not DNSSEC aware, stop doing DNSSEC for that DNSServer. Note that by setting the // req_DO to false here, the next retransmission for this question will turn off validation // and hence retransmit without the EDNS0/DOK option. if (DNSSECOptionalQuestion(qptr) && qptr->qDNSServer && !qptr->qDNSServer->DNSSECAware) { LogInfo("mDNSCoreReceiveResponse: Server %p responded with code %d to DNSSEC Query %##s (%s), clear DO flag", qptr->qDNSServer, rcode, q.qname.c, DNSTypeName(q.qtype)); qptr->qDNSServer->req_DO = mDNSfalse; } // For Unicast DNS Queries, penalize the DNSServer else { LogInfo("mDNSCoreReceiveResponse: Server %p responded with code %d to query %##s (%s)", qptr->qDNSServer, rcode, q.qname.c, DNSTypeName(q.qtype)); PenalizeDNSServer(m, qptr, response->h.flags); } } returnEarly = mDNStrue; } } } if (returnEarly) { LogInfo("Ignoring %2d Answer%s %2d Authorit%s %2d Additional%s", response->h.numAnswers, response->h.numAnswers == 1 ? ", " : "s,", response->h.numAuthorities, response->h.numAuthorities == 1 ? "y, " : "ies,", response->h.numAdditionals, response->h.numAdditionals == 1 ? "" : "s"); // not goto exit because we won't have any CacheFlushRecords and we do not want to // generate negative cache entries (we want to query the next server) return; } if (unicastQuestion && DNSSECQuestion(unicastQuestion)) { BumpDNSSECStats(m, kStatsActionSet, kStatsTypeMsgSize, (end - response->data)); } } // Parse the NSEC3 records from the Authority section before we process // the Answer section so that we can cache them along with the proper // cache records we create. if (mDNSOpaque16IsZero(response->h.id)) mDNSParseNSEC3Records(m, response, end, InterfaceID, &McastNSEC3Records); for (i = 0; i < totalrecords && ptr && ptr < end; i++) { // All responses sent via LL multicast are acceptable for caching // All responses received over our outbound TCP connections are acceptable for caching // We accept all records in a unicast response to a multicast query once we find one that // answers an active question. mDNSBool AcceptableResponse = ResponseMCast || !dstaddr || LLQType || recordAcceptedInResponse; // (Note that just because we are willing to cache something, that doesn't necessarily make it a trustworthy answer // to any specific question -- any code reading records from the cache needs to make that determination for itself.) const mDNSu8 RecordType = (i < firstauthority ) ? (mDNSu8)kDNSRecordTypePacketAns : (i < firstadditional) ? (mDNSu8)kDNSRecordTypePacketAuth : (mDNSu8)kDNSRecordTypePacketAdd; ptr = GetLargeResourceRecord(m, response, ptr, end, InterfaceID, RecordType, &m->rec); if (!ptr) goto exit; // Break out of the loop and clean up our CacheFlushRecords list before exiting if (m->rec.r.resrec.RecordType == kDNSRecordTypePacketNegative) { mDNSCoreResetRecord(m); continue; } // We have already parsed the NSEC3 records and cached them approrpriately for // multicast responses. if (mDNSOpaque16IsZero(response->h.id) && m->rec.r.resrec.rrtype == kDNSType_NSEC3) { mDNSCoreResetRecord(m); continue; } // Don't want to cache OPT or TSIG pseudo-RRs if (m->rec.r.resrec.rrtype == kDNSType_TSIG) { mDNSCoreResetRecord(m); continue; } if (m->rec.r.resrec.rrtype == kDNSType_OPT) { const rdataOPT *opt; const rdataOPT *const e = (const rdataOPT *)&m->rec.r.resrec.rdata->u.data[m->rec.r.resrec.rdlength]; // Find owner sub-option(s). We verify that the MAC is non-zero, otherwise we could inadvertently // delete all our own AuthRecords (which are identified by having zero MAC tags on them). for (opt = &m->rec.r.resrec.rdata->u.opt[0]; opt < e; opt++) if (opt->opt == kDNSOpt_Owner && opt->u.owner.vers == 0 && opt->u.owner.HMAC.l[0]) { ClearProxyRecords(m, &opt->u.owner, m->DuplicateRecords); ClearProxyRecords(m, &opt->u.owner, m->ResourceRecords); } mDNSCoreResetRecord(m); continue; } // if a CNAME record points to itself, then don't add it to the cache if ((m->rec.r.resrec.rrtype == kDNSType_CNAME) && SameDomainName(m->rec.r.resrec.name, &m->rec.r.resrec.rdata->u.name)) { LogInfo("mDNSCoreReceiveResponse: CNAME loop domain name %##s", m->rec.r.resrec.name->c); mDNSCoreResetRecord(m); continue; } // When we receive uDNS LLQ responses, we assume a long cache lifetime -- // In the case of active LLQs, we'll get remove events when the records actually do go away // In the case of polling LLQs, we assume the record remains valid until the next poll if (!mDNSOpaque16IsZero(response->h.id)) m->rec.r.resrec.rroriginalttl = GetEffectiveTTL(LLQType, m->rec.r.resrec.rroriginalttl); // If response was not sent via LL multicast, // then see if it answers a recent query of ours, which would also make it acceptable for caching. if (!ResponseMCast) { if (LLQType) { // For Long Lived queries that are both sent over UDP and Private TCP, LLQType is set. // Even though it is AcceptableResponse, we need a matching DNSServer pointer for the // queries to get ADD/RMV events. To lookup the question, we can't use // ExpectingUnicastResponseForRecord as the port numbers don't match. uDNS_recvLLQRespose // has already matched the question using the 64 bit Id in the packet and we use that here. if (llqMatch != mDNSNULL) m->rec.r.resrec.rDNSServer = uDNSServer = llqMatch->qDNSServer; // If this is a DNSSEC question that is also LongLived, don't accept records from the // Additional/Authority section blindly. We need to go through IsAcceptableResponse below // so that NSEC/NSEC3 record are cached in the nseclist if we accept them. This can happen // for both negative responses and wildcard expanded positive responses as both of come // back with NSEC/NSEC3s. if (unicastQuestion && DNSSECQuestion(unicastQuestion)) AcceptableResponse = mDNSfalse; } else if (!AcceptableResponse || !dstaddr) { // For responses that come over TCP (Responses that can't fit within UDP) or TLS (Private queries // that are not long lived e.g., AAAA lookup in a Private domain), it is indicated by !dstaddr. // Even though it is AcceptableResponse, we still need a DNSServer pointer for the resource records that // we create. DNSQuestion *q = ExpectingUnicastResponseForRecord(m, srcaddr, ResponseSrcLocal, dstport, response->h.id, &m->rec.r, !dstaddr); // Initialize the DNS server on the resource record which will now filter what questions we answer with // this record. // // We could potentially lookup the DNS server based on the source address, but that may not work always // and that's why ExpectingUnicastResponseForRecord does not try to verify whether the response came // from the DNS server that queried. We follow the same logic here. If we can find a matching quetion based // on the "id" and "source port", then this response answers the question and assume the response // came from the same DNS server that we sent the query to. if (q != mDNSNULL) { AcceptableResponse = mDNStrue; if (!InterfaceID) { debugf("mDNSCoreReceiveResponse: InterfaceID %p %##s (%s)", q->InterfaceID, q->qname.c, DNSTypeName(q->qtype)); m->rec.r.resrec.rDNSServer = uDNSServer = q->qDNSServer; } else { // Accept all remaining records in this unicast response to an mDNS query. recordAcceptedInResponse = mDNStrue; LogInfo("mDNSCoreReceiveResponse: Accepting response for query: %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); } } else { // If we can't find a matching question, we need to see whether we have seen records earlier that matched // the question. The code below does that. So, make this record unacceptable for now if (!InterfaceID) { debugf("mDNSCoreReceiveResponse: Can't find question for record name %##s", m->rec.r.resrec.name->c); AcceptableResponse = mDNSfalse; } } } } else if (llintf && llintf->IgnoreIPv4LL && m->rec.r.resrec.rrtype == kDNSType_A) { // There are some routers (rare, thankfully) that generate bogus ARP responses for // any IPv4 address they don’t recognize, including RFC 3927 IPv4 link-local addresses. // To work with these broken routers, client devices need to blacklist these broken // routers and ignore their bogus ARP responses. Some devices implement a technique // such as the one described in US Patent 7436783, which lets clients detect and // ignore these broken routers: // OS X and iOS do not implement this defensive mechanism, instead taking a simpler // approach of just detecting these broken routers and completely disabling IPv4 // link-local communication on interfaces where a broken router is detected. // OS X and iOS set the IFEF_ARPLL interface flag on interfaces // that are deemed “safe” for IPv4 link-local communication; // the flag is cleared on interfaces where a broken router is detected. // OS X and iOS will not even try to communicate with an IPv4 // link-local destination on an interface without the IFEF_ARPLL flag set. // This can cause some badly written applications to freeze for a long time if they // attempt to connect to an IPv4 link-local destination address and then wait for // that connection attempt to time out before trying other candidate addresses. // To mask this client bug, we suppress acceptance of IPv4 link-local address // records on interfaces where we know the OS will be unwilling even to attempt // communication with those IPv4 link-local destination addresses. // kSuppress IPv4LL answers on interfaces without IFEF_ARPLL const CacheRecord *const rr = &m->rec.r; const RDataBody2 *const rdb = (RDataBody2 *)rr->smallrdatastorage.data; if (mDNSv4AddressIsLinkLocal(&rdb->ipv4)) { LogInfo("mDNSResponder: Dropping LinkLocal packet %s", CRDisplayString(m, &m->rec.r)); mDNSCoreResetRecord(m); continue; } } // 1. Check that this packet resource record does not conflict with any of ours if (mDNSOpaque16IsZero(response->h.id) && m->rec.r.resrec.rrtype != kDNSType_NSEC) { if (m->CurrentRecord) LogMsg("mDNSCoreReceiveResponse ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); m->CurrentRecord = m->ResourceRecords; while (m->CurrentRecord) { AuthRecord *rr = m->CurrentRecord; m->CurrentRecord = rr->next; // We accept all multicast responses, and unicast responses resulting from queries we issued // For other unicast responses, this code accepts them only for responses with an // (apparently) local source address that pertain to a record of our own that's in probing state if (!AcceptableResponse && !(ResponseSrcLocal && rr->resrec.RecordType == kDNSRecordTypeUnique)) continue; if (PacketRRMatchesSignature(&m->rec.r, rr)) // If interface, name, type (if shared record) and class match... { // ... check to see if type and rdata are identical if (IdenticalSameNameRecord(&m->rec.r.resrec, &rr->resrec)) { // If the RR in the packet is identical to ours, just check they're not trying to lower the TTL on us if (m->rec.r.resrec.rroriginalttl >= rr->resrec.rroriginalttl/2 || m->SleepState) { // If we were planning to send on this -- and only this -- interface, then we don't need to any more if (rr->ImmedAnswer == InterfaceID) { rr->ImmedAnswer = mDNSNULL; rr->ImmedUnicast = mDNSfalse; } } else { if (rr->ImmedAnswer == mDNSNULL) { rr->ImmedAnswer = InterfaceID; m->NextScheduledResponse = m->timenow; } else if (rr->ImmedAnswer != InterfaceID) { rr->ImmedAnswer = mDNSInterfaceMark; m->NextScheduledResponse = m->timenow; } } } // else, the packet RR has different type or different rdata -- check to see if this is a conflict else if (m->rec.r.resrec.rroriginalttl > 0 && PacketRRConflict(m, rr, &m->rec.r)) { LogInfo("mDNSCoreReceiveResponse: Pkt Record: %08lX %s", m->rec.r.resrec.rdatahash, CRDisplayString(m, &m->rec.r)); LogInfo("mDNSCoreReceiveResponse: Our Record: %08lX %s", rr->resrec.rdatahash, ARDisplayString(m, rr)); // If this record is marked DependentOn another record for conflict detection purposes, // then *that* record has to be bumped back to probing state to resolve the conflict if (rr->DependentOn) { while (rr->DependentOn) rr = rr->DependentOn; LogInfo("mDNSCoreReceiveResponse: Dep Record: %08lX %s", rr->resrec.rdatahash, ARDisplayString(m, rr)); } // If we've just whacked this record's ProbeCount, don't need to do it again if (rr->ProbeCount > DefaultProbeCountForTypeUnique) LogInfo("mDNSCoreReceiveResponse: Already reset to Probing: %s", ARDisplayString(m, rr)); else if (rr->ProbeCount == DefaultProbeCountForTypeUnique) LogInfo("mDNSCoreReceiveResponse: Ignoring response received before we even began probing: %s", ARDisplayString(m, rr)); else { LogMsg("mDNSCoreReceiveResponse: Received from %#a:%d %s", srcaddr, mDNSVal16(srcport), CRDisplayString(m, &m->rec.r)); // If we'd previously verified this record, put it back to probing state and try again if (rr->resrec.RecordType == kDNSRecordTypeVerified) { LogMsg("mDNSCoreReceiveResponse: Resetting to Probing: %s", ARDisplayString(m, rr)); rr->resrec.RecordType = kDNSRecordTypeUnique; // We set ProbeCount to one more than the usual value so we know we've already touched this record. // This is because our single probe for "example-name.local" could yield a response with (say) two A records and // three AAAA records in it, and we don't want to call RecordProbeFailure() five times and count that as five conflicts. // This special value is recognised and reset to DefaultProbeCountForTypeUnique in SendQueries(). rr->ProbeCount = DefaultProbeCountForTypeUnique + 1; rr->AnnounceCount = InitialAnnounceCount; InitializeLastAPTime(m, rr); RecordProbeFailure(m, rr); // Repeated late conflicts also cause us to back off to the slower probing rate } // If we're probing for this record, we just failed else if (rr->resrec.RecordType == kDNSRecordTypeUnique) { // At this point in the code, we're probing for uniqueness. // We've sent at least one probe (rr->ProbeCount < DefaultProbeCountForTypeUnique) // but we haven't completed probing yet (rr->resrec.RecordType == kDNSRecordTypeUnique). // Before we call deregister, check if this is a packet we registered with the sleep proxy. if (!mDNSCoreRegisteredProxyRecord(m, rr)) { // This may be a conflict due to stale packets on the network. Delay probing by a second. // If there are conflicts after 3 such attempts, then it is a true conflict. if (m->DelayConflictProcessing) { m->DelayConflictProcessing--; LogMsg("Possible spurious conflict for %s. Attempt %d at suppressing probes for one second", ARDisplayString(m, rr), (MAX_CONFLICT_PROCESSING_DELAYS - m->DelayConflictProcessing)); rr->ProbeCount = DefaultProbeCountForTypeUnique + 1; rr->AnnounceCount = InitialAnnounceCount; m->SuppressProbes = NonZeroTime(m->timenow + mDNSPlatformOneSecond); InitializeLastAPTime(m, rr); RecordProbeFailure(m, rr); // Repeated late conflicts also cause us to back off to the slower probing rate } else { LogMsg("mDNSCoreReceiveResponse: ProbeCount %d; will deregister %s", rr->ProbeCount, ARDisplayString(m, rr)); m->mDNSStats.NameConflicts++; #if APPLE_OSX_mDNSResponder // See if this record was also registered with any D2D plugins. D2D_stop_advertising_record(rr); #endif mDNS_Deregister_internal(m, rr, mDNS_Dereg_conflict); } } } // We assumed this record must be unique, but we were wrong. (e.g. There are two mDNSResponders on the // same machine giving different answers for the reverse mapping record, or there are two machines on the // network using the same IP address.) This is simply a misconfiguration, and there's nothing we can do // to fix it -- e.g. it's not our job to be trying to change the machine's IP address. We just discard our // record to avoid continued conflicts (as we do for a conflict on our Unique records) and get on with life. else if (rr->resrec.RecordType == kDNSRecordTypeKnownUnique) { LogMsg("mDNSCoreReceiveResponse: Unexpected conflict discarding %s", ARDisplayString(m, rr)); m->mDNSStats.KnownUniqueNameConflicts++; #if APPLE_OSX_mDNSResponder D2D_stop_advertising_record(rr); #endif mDNS_Deregister_internal(m, rr, mDNS_Dereg_conflict); } else LogMsg("mDNSCoreReceiveResponse: Unexpected record type %X %s", rr->resrec.RecordType, ARDisplayString(m, rr)); } } // Else, matching signature, different type or rdata, but not a considered a conflict. // If the packet record has the cache-flush bit set, then we check to see if we // have any record(s) of the same type that we should re-assert to rescue them // (see note about "multi-homing and bridged networks" at the end of this function). else if (m->rec.r.resrec.rrtype == rr->resrec.rrtype) if ((m->rec.r.resrec.RecordType & kDNSRecordTypePacketUniqueMask) && (mDNSu32)(m->timenow - rr->LastMCTime) > (mDNSu32)mDNSPlatformOneSecond/2) { rr->ImmedAnswer = mDNSInterfaceMark; m->NextScheduledResponse = m->timenow; } } } } nseclist = mDNSfalse; if (!AcceptableResponse) { AcceptableResponse = IsResponseAcceptable(m, CacheFlushRecords, unicastQuestion, &nseclist); if (AcceptableResponse) m->rec.r.resrec.rDNSServer = uDNSServer; } // 2. See if we want to add this packet resource record to our cache // We only try to cache answers if we have a cache to put them in // Also, we ignore any apparent attempts at cache poisoning unicast to us that do not answer any outstanding active query if (!AcceptableResponse) LogInfo("mDNSCoreReceiveResponse ignoring %s", CRDisplayString(m, &m->rec.r)); if (m->rrcache_size && AcceptableResponse) { const mDNSu32 slot = HashSlotFromNameHash(m->rec.r.resrec.namehash); CacheGroup *cg = CacheGroupForRecord(m, &m->rec.r.resrec); CacheRecord *rr = mDNSNULL; if (McastNSEC3Records) InitializeAnonInfoForCR(m, &McastNSEC3Records, &m->rec.r); // 2a. Check if this packet resource record is already in our cache. // // If this record should go in the nseclist, don't look in the cache for updating it. // They are supposed to be cached under the "nsec" field of the cache record for // validation. Just create the cache record. if (!nseclist) { rr = mDNSCoreReceiveCacheCheck(m, response, LLQType, slot, cg, unicastQuestion, &cfp, &NSECCachePtr, InterfaceID); } // If packet resource record not in our cache, add it now // (unless it is just a deletion of a record we never had, in which case we don't care) if (!rr && m->rec.r.resrec.rroriginalttl > 0) { const mDNSBool AddToCFList = (m->rec.r.resrec.RecordType & kDNSRecordTypePacketUniqueMask) && (LLQType != uDNS_LLQ_Events); mDNSs32 delay; if (AddToCFList) delay = NonZeroTime(m->timenow + mDNSPlatformOneSecond); else delay = CheckForSoonToExpireRecords(m, m->rec.r.resrec.name, m->rec.r.resrec.namehash, mDNSNULL); // If unique, assume we may have to delay delivery of this 'add' event. // Below, where we walk the CacheFlushRecords list, we either call CacheRecordDeferredAdd() // to immediately to generate answer callbacks, or we call ScheduleNextCacheCheckTime() // to schedule an mDNS_Execute task at the appropriate time. rr = CreateNewCacheEntry(m, slot, cg, delay, !nseclist, srcaddr); if (rr) { rr->responseFlags = response->h.flags; // If we are not creating signatures, then we need to inform DNSSEC so that // it does not wait forever. Don't do this if we got NSEC records // as it indicates that this name does not exist. if (rr->resrec.rrtype == kDNSType_RRSIG && !nseclist) { rrsigsCreated = mDNStrue; } // Remember whether we created a cache record in response to a DNSSEC question. // This helps DNSSEC code not to reissue the question to fetch the DNSSEC records. rr->CRDNSSECQuestion = 0; if (unicastQuestion && DNSSECQuestion(unicastQuestion)) { LogInfo("mDNSCoreReceiveResponse: CRDNSSECQuestion set for new record %s, question %##s (%s)", CRDisplayString(m, rr), unicastQuestion->qname.c, DNSTypeName(unicastQuestion->qtype)); rr->CRDNSSECQuestion = 1; } // NSEC/NSEC3 records and its signatures are cached with the negative cache entry // which we should be creating below. It is also needed in the wildcard // expanded answer case and in that case it is cached along with the answer. if (nseclist) { rr->TimeRcvd = m->timenow; *nsecp = rr; nsecp = &rr->next; } else if (AddToCFList) { *cfp = rr; cfp = &rr->NextInCFList; *cfp = (CacheRecord*)1; } else if (rr->DelayDelivery) { ScheduleNextCacheCheckTime(m, slot, rr->DelayDelivery); } } } else { if (rr && rr->resrec.AnonInfo && m->rec.r.resrec.AnonInfo) { CopyAnonInfoForCR(m, rr, &m->rec.r); } } } mDNSCoreResetRecord(m); } exit: mDNSCoreResetRecord(m); // If we've just received one or more records with their cache flush bits set, // then scan that cache slot to see if there are any old stale records we need to flush while (CacheFlushRecords != (CacheRecord*)1) { CacheRecord *r1 = CacheFlushRecords, *r2; const mDNSu32 slot = HashSlotFromNameHash(r1->resrec.namehash); const CacheGroup *cg = CacheGroupForRecord(m, &r1->resrec); CacheFlushRecords = CacheFlushRecords->NextInCFList; r1->NextInCFList = mDNSNULL; // Look for records in the cache with the same signature as this new one with the cache flush // bit set, and either (a) if they're fresh, just make sure the whole RRSet has the same TTL // (as required by DNS semantics) or (b) if they're old, mark them for deletion in one second. // We make these TTL adjustments *only* for records that still have *more* than one second // remaining to live. Otherwise, a record that we tagged for deletion half a second ago // (and now has half a second remaining) could inadvertently get its life extended, by either // (a) if we got an explicit goodbye packet half a second ago, the record would be considered // "fresh" and would be incorrectly resurrected back to the same TTL as the rest of the RRSet, // or (b) otherwise, the record would not be fully resurrected, but would be reset to expire // in one second, thereby inadvertently delaying its actual expiration, instead of hastening it. // If this were to happen repeatedly, the record's expiration could be deferred indefinitely. // To avoid this, we need to ensure that the cache flushing operation will only act to // *decrease* a record's remaining lifetime, never *increase* it. for (r2 = cg ? cg->members : mDNSNULL; r2; r2=r2->next) { mDNSu16 id1; mDNSu16 id2; if (!r1->resrec.InterfaceID) { id1 = (r1->resrec.rDNSServer ? r1->resrec.rDNSServer->resGroupID : 0); id2 = (r2->resrec.rDNSServer ? r2->resrec.rDNSServer->resGroupID : 0); } else { id1 = id2 = 0; } // When we receive new RRSIGs e.g., for DNSKEY record, we should not flush the old // RRSIGS e.g., for TXT record. To do so, we need to look at the typeCovered field of // the new RRSIG that we received. Process only if the typeCovered matches. if ((r1->resrec.rrtype == r2->resrec.rrtype) && (r1->resrec.rrtype == kDNSType_RRSIG)) { rdataRRSig *rrsig1 = (rdataRRSig *)(((RDataBody2 *)(r1->resrec.rdata->u.data))->data); rdataRRSig *rrsig2 = (rdataRRSig *)(((RDataBody2 *)(r2->resrec.rdata->u.data))->data); if (swap16(rrsig1->typeCovered) != swap16(rrsig2->typeCovered)) { debugf("mDNSCoreReceiveResponse: Received RRSIG typeCovered %s, found %s, not processing", DNSTypeName(swap16(rrsig1->typeCovered)), DNSTypeName(swap16(rrsig2->typeCovered))); continue; } } // For Unicast (null InterfaceID) the resolver IDs should also match if ((r1->resrec.InterfaceID == r2->resrec.InterfaceID) && (r1->resrec.InterfaceID || (id1 == id2)) && r1->resrec.rrtype == r2->resrec.rrtype && r1->resrec.rrclass == r2->resrec.rrclass) { // If record is recent, just ensure the whole RRSet has the same TTL (as required by DNS semantics) // else, if record is old, mark it to be flushed if (m->timenow - r2->TimeRcvd < mDNSPlatformOneSecond && RRExpireTime(r2) - m->timenow > mDNSPlatformOneSecond) { // If we find mismatched TTLs in an RRSet, correct them. // We only do this for records with a TTL of 2 or higher. It's possible to have a // goodbye announcement with the cache flush bit set (or a case-change on record rdata, // which we treat as a goodbye followed by an addition) and in that case it would be // inappropriate to synchronize all the other records to a TTL of 0 (or 1). // We suppress the message for the specific case of correcting from 240 to 60 for type TXT, // because certain early Bonjour devices are known to have this specific mismatch, and // there's no point filling syslog with messages about something we already know about. // We also don't log this for uDNS responses, since a caching name server is obliged // to give us an aged TTL to correct for how long it has held the record, // so our received TTLs are expected to vary in that case // We also suppress log message in the case of SRV records that are received // with a TTL of 4500 that are already cached with a TTL of 120 seconds, since // this behavior was observed for a number of discoveryd based AppleTV's in iOS 8 // GM builds. if (r2->resrec.rroriginalttl != r1->resrec.rroriginalttl && r1->resrec.rroriginalttl > 1) { if (!(r2->resrec.rroriginalttl == 240 && r1->resrec.rroriginalttl == 60 && r2->resrec.rrtype == kDNSType_TXT) && !(r2->resrec.rroriginalttl == 120 && r1->resrec.rroriginalttl == 4500 && r2->resrec.rrtype == kDNSType_SRV) && mDNSOpaque16IsZero(response->h.id)) LogInfo("Correcting TTL from %4d to %4d for %s", r2->resrec.rroriginalttl, r1->resrec.rroriginalttl, CRDisplayString(m, r2)); r2->resrec.rroriginalttl = r1->resrec.rroriginalttl; } r2->TimeRcvd = m->timenow; } else // else, if record is old, mark it to be flushed { verbosedebugf("Cache flush new %p age %d expire in %d %s", r1, m->timenow - r1->TimeRcvd, RRExpireTime(r1) - m->timenow, CRDisplayString(m, r1)); verbosedebugf("Cache flush old %p age %d expire in %d %s", r2, m->timenow - r2->TimeRcvd, RRExpireTime(r2) - m->timenow, CRDisplayString(m, r2)); // We set stale records to expire in one second. // This gives the owner a chance to rescue it if necessary. // This is important in the case of multi-homing and bridged networks: // Suppose host X is on Ethernet. X then connects to an AirPort base station, which happens to be // bridged onto the same Ethernet. When X announces its AirPort IP address with the cache-flush bit // set, the AirPort packet will be bridged onto the Ethernet, and all other hosts on the Ethernet // will promptly delete their cached copies of the (still valid) Ethernet IP address record. // By delaying the deletion by one second, we give X a change to notice that this bridging has // happened, and re-announce its Ethernet IP address to rescue it from deletion from all our caches. // We set UnansweredQueries to MaxUnansweredQueries to avoid expensive and unnecessary // final expiration queries for this record. // If a record is deleted twice, first with an explicit DE record, then a second time by virtue of the cache // flush bit on the new record replacing it, then we allow the record to be deleted immediately, without the usual // one-second grace period. This improves responsiveness for mDNS_Update(), as used for things like iChat status updates. // Updating TXT records is too slow // We check for "rroriginalttl == 1" because we want to include records tagged by the "packet TTL is zero" check above, // which sets rroriginalttl to 1, but not records tagged by the rdata case-change check, which sets rroriginalttl to 0. if (r2->TimeRcvd == m->timenow && r2->resrec.rroriginalttl == 1 && r2->UnansweredQueries == MaxUnansweredQueries) { LogInfo("Cache flush for DE record %s", CRDisplayString(m, r2)); r2->resrec.rroriginalttl = 0; } else if (RRExpireTime(r2) - m->timenow > mDNSPlatformOneSecond) { // We only set a record to expire in one second if it currently has *more* than a second to live // If it's already due to expire in a second or less, we just leave it alone r2->resrec.rroriginalttl = 1; r2->UnansweredQueries = MaxUnansweredQueries; r2->TimeRcvd = m->timenow - 1; // We use (m->timenow - 1) instead of m->timenow, because we use that to identify records // that we marked for deletion via an explicit DE record } } SetNextCacheCheckTimeForRecord(m, r2); } } if (r1->DelayDelivery) // If we were planning to delay delivery of this record, see if we still need to { // If we had a unicast question for this response with at least one positive answer and we // have NSECRecords, it is most likely a wildcard expanded answer. Cache the NSEC and its // signatures along with the cache record which will be used for validation later. If // we rescued a few records earlier in this function, then NSECCachePtr would be set. In that // use that instead. if (response->h.numAnswers && unicastQuestion && NSECRecords) { if (!NSECCachePtr) { LogInfo("mDNSCoreReceiveResponse: Updating NSECCachePtr to %s", CRDisplayString(m, r1)); NSECCachePtr = r1; } // Note: We need to do this before we call CacheRecordDeferredAdd as this // might start the verification process which needs these NSEC records if (!AddNSECSForCacheRecord(m, NSECRecords, NSECCachePtr, rcode)) { LogInfo("mDNSCoreReceiveResponse: AddNSECSForCacheRecord failed to add NSEC for %s", CRDisplayString(m, NSECCachePtr)); FreeNSECRecords(m, NSECRecords); } NSECRecords = mDNSNULL; NSECCachePtr = mDNSNULL; } r1->DelayDelivery = CheckForSoonToExpireRecords(m, r1->resrec.name, r1->resrec.namehash, mDNSNULL); // If no longer delaying, deliver answer now, else schedule delivery for the appropriate time if (!r1->DelayDelivery) CacheRecordDeferredAdd(m, r1); else ScheduleNextCacheCheckTime(m, slot, r1->DelayDelivery); } } // If we have not consumed the NSEC records yet e.g., just refreshing the cache, // update them now for future validations. if (NSECRecords && NSECCachePtr) { LogInfo("mDNSCoreReceieveResponse: Updating NSEC records in %s", CRDisplayString(m, NSECCachePtr)); if (!AddNSECSForCacheRecord(m, NSECRecords, NSECCachePtr, rcode)) { LogInfo("mDNSCoreReceiveResponse: AddNSECSForCacheRecord failed to add NSEC for %s", CRDisplayString(m, NSECCachePtr)); FreeNSECRecords(m, NSECRecords); } NSECRecords = mDNSNULL; NSECCachePtr = mDNSNULL; } // If there is at least one answer and we did not create RRSIGs and there was a // ValidatingResponse question waiting for this response, give a hint that no RRSIGs // were created. We don't need to give a hint: // // - if we have no answers, the mDNSCoreReceiveNoUnicastAnswers below should // generate a negative response // // - if we have NSECRecords, it means we might have a potential proof for // non-existence of name that we are looking for // if (response->h.numAnswers && !rrsigsCreated && DNSSECQuestion && !NSECRecords) mDNSCoreReceiveNoDNSSECAnswers(m, response, end, dstaddr, dstport, InterfaceID); // See if we need to generate negative cache entries for unanswered unicast questions mDNSCoreReceiveNoUnicastAnswers(m, response, end, dstaddr, dstport, InterfaceID, LLQType, rcode, NSECRecords); if (McastNSEC3Records) { debugf("mDNSCoreReceiveResponse: McastNSEC3Records not used"); FreeNSECRecords(m, McastNSEC3Records); } } // ScheduleWakeup causes all proxy records with WakeUp.HMAC matching mDNSEthAddr 'e' to be deregistered, causing // multiple wakeup magic packets to be sent if appropriate, and all records to be ultimately freed after a few seconds. // ScheduleWakeup is called on mDNS record conflicts, ARP conflicts, NDP conflicts, or reception of trigger traffic // that warrants waking the sleeping host. // ScheduleWakeup must be called with the lock held (ScheduleWakeupForList uses mDNS_Deregister_internal) mDNSlocal void ScheduleWakeupForList(mDNS *const m, mDNSInterfaceID InterfaceID, mDNSEthAddr *e, AuthRecord *const thelist) { // We need to use the m->CurrentRecord mechanism here when dealing with DuplicateRecords list as // mDNS_Deregister_internal deregisters duplicate records immediately as they are not used // to send wakeups or goodbyes. See the comment in that function for more details. To keep it // simple, we use the same mechanism for both lists. if (!e->l[0]) { LogMsg("ScheduleWakeupForList ERROR: Target HMAC is zero"); return; } m->CurrentRecord = thelist; while (m->CurrentRecord) { AuthRecord *const rr = m->CurrentRecord; if (rr->resrec.InterfaceID == InterfaceID && rr->resrec.RecordType != kDNSRecordTypeDeregistering && mDNSSameEthAddress(&rr->WakeUp.HMAC, e)) { LogInfo("ScheduleWakeupForList: Scheduling wakeup packets for %s", ARDisplayString(m, rr)); mDNS_Deregister_internal(m, rr, mDNS_Dereg_normal); } if (m->CurrentRecord == rr) // If m->CurrentRecord was not advanced for us, do it now m->CurrentRecord = rr->next; } } mDNSlocal void ScheduleWakeup(mDNS *const m, mDNSInterfaceID InterfaceID, mDNSEthAddr *e) { if (!e->l[0]) { LogMsg("ScheduleWakeup ERROR: Target HMAC is zero"); return; } ScheduleWakeupForList(m, InterfaceID, e, m->DuplicateRecords); ScheduleWakeupForList(m, InterfaceID, e, m->ResourceRecords); } mDNSlocal void SPSRecordCallback(mDNS *const m, AuthRecord *const ar, mStatus result) { if (result && result != mStatus_MemFree) LogInfo("SPS Callback %d %s", result, ARDisplayString(m, ar)); if (result == mStatus_NameConflict) { mDNS_Lock(m); LogMsg("%-7s Conflicting mDNS -- waking %.6a %s", InterfaceNameForID(m, ar->resrec.InterfaceID), &ar->WakeUp.HMAC, ARDisplayString(m, ar)); if (ar->WakeUp.HMAC.l[0]) { SendWakeup(m, ar->resrec.InterfaceID, &ar->WakeUp.IMAC, &ar->WakeUp.password, mDNSfalse); // Send one wakeup magic packet ScheduleWakeup(m, ar->resrec.InterfaceID, &ar->WakeUp.HMAC); // Schedule all other records with the same owner to be woken } mDNS_Unlock(m); } if (result == mStatus_NameConflict || result == mStatus_MemFree) { m->ProxyRecords--; mDNSPlatformMemFree(ar); mDNS_UpdateAllowSleep(m); } } mDNSlocal mDNSu8 *GetValueForMACAddr(mDNSu8 *ptr, mDNSu8 *limit, mDNSEthAddr *eth) { int i; mDNSs8 hval = 0; int colons = 0; mDNSu8 val = 0; for (i = 0; ptr < limit && *ptr != ' ' && i < 17; i++, ptr++) { hval = HexVal(*ptr); if (hval != -1) { val <<= 4; val |= hval; } else if (*ptr == ':') { if (colons >=5) { LogMsg("GetValueForMACAddr: Address malformed colons %d val %d", colons, val); return mDNSNULL; } eth->b[colons] = val; colons++; val = 0; } } if (colons != 5) { LogMsg("GetValueForMACAddr: Address malformed colons %d", colons); return mDNSNULL; } eth->b[colons] = val; return ptr; } mDNSlocal mDNSu8 *GetValueForIPv6Addr(mDNSu8 *ptr, mDNSu8 *limit, mDNSv6Addr *v6) { int hval; int value; int numBytes; int digitsProcessed; int zeroFillStart; int numColons; mDNSu8 v6addr[16]; // RFC 3513: Section 2.2 specifies IPv6 presentation format. The following parsing // handles both (1) and (2) and does not handle embedded IPv4 addresses. // // First forms a address in "v6addr", then expands to fill the zeroes in and returns // the result in "v6" numColons = numBytes = value = digitsProcessed = zeroFillStart = 0; while (ptr < limit && *ptr != ' ') { hval = HexVal(*ptr); if (hval != -1) { value <<= 4; value |= hval; digitsProcessed = 1; } else if (*ptr == ':') { if (!digitsProcessed) { // If we have already seen a "::", we should not see one more. Handle the special // case of "::" if (numColons) { // if we never filled any bytes and the next character is space (we have reached the end) // we are done if (!numBytes && (ptr + 1) < limit && *(ptr + 1) == ' ') { mDNSPlatformMemZero(v6->b, 16); return ptr + 1; } LogMsg("GetValueForIPv6Addr: zeroFillStart non-zero %d", zeroFillStart); return mDNSNULL; } // We processed "::". We need to fill zeroes later. For now, mark the // point where we will start filling zeroes from. zeroFillStart = numBytes; numColons++; } else if ((ptr + 1) < limit && *(ptr + 1) == ' ') { // We have a trailing ":" i.e., no more characters after ":" LogMsg("GetValueForIPv6Addr: Trailing colon"); return mDNSNULL; } else { // For a fully expanded IPv6 address, we fill the 14th and 15th byte outside of this while // loop below as there is no ":" at the end. Hence, the last two bytes that can possibly // filled here is 12 and 13. if (numBytes > 13) { LogMsg("GetValueForIPv6Addr:1: numBytes is %d", numBytes); return mDNSNULL; } v6addr[numBytes++] = (mDNSu8) ((value >> 8) & 0xFF); v6addr[numBytes++] = (mDNSu8) (value & 0xFF); digitsProcessed = value = 0; // Make sure that we did not fill the 13th and 14th byte above if (numBytes > 14) { LogMsg("GetValueForIPv6Addr:2: numBytes is %d", numBytes); return mDNSNULL; } } } ptr++; } // We should be processing the last set of bytes following the last ":" here if (!digitsProcessed) { LogMsg("GetValueForIPv6Addr: no trailing bytes after colon, numBytes is %d", numBytes); return mDNSNULL; } if (numBytes > 14) { LogMsg("GetValueForIPv6Addr:3: numBytes is %d", numBytes); return mDNSNULL; } v6addr[numBytes++] = (mDNSu8) ((value >> 8) & 0xFF); v6addr[numBytes++] = (mDNSu8) (value & 0xFF); if (zeroFillStart) { int i, j, n; for (i = 0; i < zeroFillStart; i++) v6->b[i] = v6addr[i]; for (j = i, n = 0; n < 16 - numBytes; j++, n++) v6->b[j] = 0; for (; j < 16; i++, j++) v6->b[j] = v6addr[i]; } else if (numBytes == 16) mDNSPlatformMemCopy(v6->b, v6addr, 16); else { LogMsg("GetValueForIPv6addr: Not enough bytes for IPv6 address, numBytes is %d", numBytes); return mDNSNULL; } return ptr; } mDNSlocal mDNSu8 *GetValueForIPv4Addr(mDNSu8 *ptr, mDNSu8 *limit, mDNSv4Addr *v4) { mDNSu32 val; int dots = 0; val = 0; for ( ; ptr < limit && *ptr != ' '; ptr++) { if (*ptr >= '0' && *ptr <= '9') val = val * 10 + *ptr - '0'; else if (*ptr == '.') { if (val > 255 || dots >= 3) { LogMsg("GetValueForIPv4Addr: something wrong ptr(%p) %c, limit %p, dots %d", ptr, *ptr, limit, dots); return mDNSNULL; } v4->b[dots++] = val; val = 0; } else { // We have a zero at the end and if we reached that, then we are done. if (*ptr == 0 && ptr == limit - 1 && dots == 3) { v4->b[dots] = val; return ptr + 1; } else { LogMsg("GetValueForIPv4Addr: something wrong ptr(%p) %c, limit %p, dots %d", ptr, *ptr, limit, dots); return mDNSNULL; } } } if (dots != 3) { LogMsg("GetValueForIPv4Addr: Address malformed dots %d", dots); return mDNSNULL; } v4->b[dots] = val; return ptr; } mDNSlocal mDNSu8 *GetValueForKeepalive(mDNSu8 *ptr, mDNSu8 *limit, mDNSu32 *value) { mDNSu32 val; val = 0; for ( ; ptr < limit && *ptr != ' '; ptr++) { if (*ptr < '0' || *ptr > '9') { // We have a zero at the end and if we reached that, then we are done. if (*ptr == 0 && ptr == limit - 1) { *value = val; return ptr + 1; } else { LogMsg("GetValueForKeepalive: *ptr %d, ptr %p, limit %p, ptr +1 %d", *ptr, ptr, limit, *(ptr + 1)); return mDNSNULL; } } val = val * 10 + *ptr - '0'; } *value = val; return ptr; } mDNSexport mDNSBool mDNSValidKeepAliveRecord(AuthRecord *rr) { mDNSAddr laddr, raddr; mDNSEthAddr eth; mDNSIPPort lport, rport; mDNSu32 timeout, seq, ack; mDNSu16 win; if (!mDNS_KeepaliveRecord(&rr->resrec)) { return mDNSfalse; } timeout = seq = ack = 0; win = 0; laddr = raddr = zeroAddr; lport = rport = zeroIPPort; eth = zeroEthAddr; mDNS_ExtractKeepaliveInfo(rr, &timeout, &laddr, &raddr, ð, &seq, &ack, &lport, &rport, &win); if (mDNSAddressIsZero(&laddr) || mDNSIPPortIsZero(lport) || mDNSAddressIsZero(&raddr) || mDNSIPPortIsZero(rport) || mDNSEthAddressIsZero(eth)) { return mDNSfalse; } return mDNStrue; } mDNSlocal void mDNS_ExtractKeepaliveInfo(AuthRecord *ar, mDNSu32 *timeout, mDNSAddr *laddr, mDNSAddr *raddr, mDNSEthAddr *eth, mDNSu32 *seq, mDNSu32 *ack, mDNSIPPort *lport, mDNSIPPort *rport, mDNSu16 *win) { if (ar->resrec.rrtype != kDNSType_NULL) return; if (mDNS_KeepaliveRecord(&ar->resrec)) { int len = ar->resrec.rdlength; mDNSu8 *ptr = &ar->resrec.rdata->u.txt.c[1]; mDNSu8 *limit = ptr + len - 1; // Exclude the first byte that is the length mDNSu32 value = 0; while (ptr < limit) { mDNSu8 param = *ptr; ptr += 2; // Skip the letter and the "=" if (param == 'h') { laddr->type = mDNSAddrType_IPv4; ptr = GetValueForIPv4Addr(ptr, limit, &laddr->ip.v4); } else if (param == 'd') { raddr->type = mDNSAddrType_IPv4; ptr = GetValueForIPv4Addr(ptr, limit, &raddr->ip.v4); } else if (param == 'H') { laddr->type = mDNSAddrType_IPv6; ptr = GetValueForIPv6Addr(ptr, limit, &laddr->ip.v6); } else if (param == 'D') { raddr->type = mDNSAddrType_IPv6; ptr = GetValueForIPv6Addr(ptr, limit, &raddr->ip.v6); } else if (param == 'm') { ptr = GetValueForMACAddr(ptr, limit, eth); } else { ptr = GetValueForKeepalive(ptr, limit, &value); } if (!ptr) { LogMsg("mDNS_ExtractKeepaliveInfo: Cannot parse\n"); return; } // Extract everything in network order so that it is easy for sending a keepalive and also // for matching incoming TCP packets switch (param) { case 't': *timeout = value; //if (*timeout < 120) *timeout = 120; break; case 'h': case 'H': case 'd': case 'D': case 'm': case 'i': case 'c': break; case 'l': lport->NotAnInteger = swap16((mDNSu16)value); break; case 'r': rport->NotAnInteger = swap16((mDNSu16)value); break; case 's': *seq = swap32(value); break; case 'a': *ack = swap32(value); break; case 'w': *win = swap16((mDNSu16)value); break; default: LogMsg("mDNS_ExtractKeepaliveInfo: unknown value %c\n", param); ptr = limit; break; } ptr++; // skip the space } } } // Matches the proxied auth records to the incoming TCP packet and returns the match and its sequence and ack in "rseq" and "rack" so that // the clients need not retrieve this information from the auth record again. mDNSlocal AuthRecord* mDNS_MatchKeepaliveInfo(mDNS *const m, const mDNSAddr* pladdr, const mDNSAddr* praddr, const mDNSIPPort plport, const mDNSIPPort prport, mDNSu32 *rseq, mDNSu32 *rack) { AuthRecord *ar; mDNSAddr laddr, raddr; mDNSEthAddr eth; mDNSIPPort lport, rport; mDNSu32 timeout, seq, ack; mDNSu16 win; for (ar = m->ResourceRecords; ar; ar=ar->next) { timeout = seq = ack = 0; win = 0; laddr = raddr = zeroAddr; lport = rport = zeroIPPort; if (!ar->WakeUp.HMAC.l[0]) continue; mDNS_ExtractKeepaliveInfo(ar, &timeout, &laddr, &raddr, ð, &seq, &ack, &lport, &rport, &win); // Did we parse correctly ? if (!timeout || mDNSAddressIsZero(&laddr) || mDNSAddressIsZero(&raddr) || !seq || !ack || mDNSIPPortIsZero(lport) || mDNSIPPortIsZero(rport) || !win) { debugf("mDNS_MatchKeepaliveInfo: not a valid record %s for keepalive", ARDisplayString(m, ar)); continue; } debugf("mDNS_MatchKeepaliveInfo: laddr %#a pladdr %#a, raddr %#a praddr %#a, lport %d plport %d, rport %d prport %d", &laddr, pladdr, &raddr, praddr, mDNSVal16(lport), mDNSVal16(plport), mDNSVal16(rport), mDNSVal16(prport)); // Does it match the incoming TCP packet ? if (mDNSSameAddress(&laddr, pladdr) && mDNSSameAddress(&raddr, praddr) && mDNSSameIPPort(lport, plport) && mDNSSameIPPort(rport, prport)) { // returning in network order *rseq = seq; *rack = ack; return ar; } } return mDNSNULL; } mDNSlocal void mDNS_SendKeepalives(mDNS *const m) { AuthRecord *ar; for (ar = m->ResourceRecords; ar; ar=ar->next) { mDNSu32 timeout, seq, ack; mDNSu16 win; mDNSAddr laddr, raddr; mDNSEthAddr eth; mDNSIPPort lport, rport; timeout = seq = ack = 0; win = 0; laddr = raddr = zeroAddr; lport = rport = zeroIPPort; if (!ar->WakeUp.HMAC.l[0]) continue; mDNS_ExtractKeepaliveInfo(ar, &timeout, &laddr, &raddr, ð, &seq, &ack, &lport, &rport, &win); if (!timeout || mDNSAddressIsZero(&laddr) || mDNSAddressIsZero(&raddr) || !seq || !ack || mDNSIPPortIsZero(lport) || mDNSIPPortIsZero(rport) || !win) { debugf("mDNS_SendKeepalives: not a valid record %s for keepalive", ARDisplayString(m, ar)); continue; } LogMsg("mDNS_SendKeepalives: laddr %#a raddr %#a lport %d rport %d", &laddr, &raddr, mDNSVal16(lport), mDNSVal16(rport)); // When we receive a proxy update, we set KATimeExpire to zero so that we always send a keepalive // immediately (to detect any potential problems). After that we always set it to a non-zero value. if (!ar->KATimeExpire || (m->timenow - ar->KATimeExpire >= 0)) { mDNSPlatformSendKeepalive(&laddr, &raddr, &lport, &rport, seq, ack, win); ar->KATimeExpire = NonZeroTime(m->timenow + timeout * mDNSPlatformOneSecond); } if (m->NextScheduledKA - ar->KATimeExpire > 0) m->NextScheduledKA = ar->KATimeExpire; } } mDNSlocal void mDNS_SendKeepaliveACK(mDNS *const m, AuthRecord *ar) { mDNSu32 timeout, seq, ack, seqInc; mDNSu16 win; mDNSAddr laddr, raddr; mDNSEthAddr eth; mDNSIPPort lport, rport; mDNSu8 *ptr; if (ar == mDNSNULL) { LogInfo("mDNS_SendKeepalivesACK: AuthRecord is NULL"); return; } timeout = seq = ack = 0; win = 0; laddr = raddr = zeroAddr; lport = rport = zeroIPPort; mDNS_ExtractKeepaliveInfo(ar, &timeout, &laddr, &raddr, ð, &seq, &ack, &lport, &rport, &win); if (!timeout || mDNSAddressIsZero(&laddr) || mDNSAddressIsZero(&raddr) || !seq || !ack || mDNSIPPortIsZero(lport) || mDNSIPPortIsZero(rport) || !win) { LogInfo("mDNS_SendKeepaliveACK: not a valid record %s for keepalive", ARDisplayString(m, ar)); return; } // To send a keepalive ACK, we need to add one to the sequence number from the keepalive // record, which is the TCP connection's "next" sequence number minus one. Otherwise, the // keepalive ACK also ends up being a keepalive probe. Also, seq is in network byte order, so // it's converted to host byte order before incrementing it by one. ptr = (mDNSu8 *)&seq; seqInc = (mDNSu32)((ptr[0] << 24) | (ptr[1] << 16) | (ptr[2] << 8) | ptr[3]) + 1; ptr[0] = (mDNSu8)((seqInc >> 24) & 0xFF); ptr[1] = (mDNSu8)((seqInc >> 16) & 0xFF); ptr[2] = (mDNSu8)((seqInc >> 8) & 0xFF); ptr[3] = (mDNSu8)((seqInc ) & 0xFF); LogMsg("mDNS_SendKeepaliveACK: laddr %#a raddr %#a lport %d rport %d", &laddr, &raddr, mDNSVal16(lport), mDNSVal16(rport)); mDNSPlatformSendKeepalive(&laddr, &raddr, &lport, &rport, seq, ack, win); } mDNSlocal void mDNSCoreReceiveUpdate(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *end, const mDNSAddr *srcaddr, const mDNSIPPort srcport, const mDNSAddr *dstaddr, mDNSIPPort dstport, const mDNSInterfaceID InterfaceID) { int i; AuthRecord opt; mDNSu8 *p = m->omsg.data; OwnerOptData owner = zeroOwner; // Need to zero this, so we'll know if this Update packet was missing its Owner option mDNSu32 updatelease = 0; const mDNSu8 *ptr; LogSPS("Received Update from %#-15a:%-5d to %#-15a:%-5d on 0x%p with " "%2d Question%s %2d Answer%s %2d Authorit%s %2d Additional%s %d bytes", srcaddr, mDNSVal16(srcport), dstaddr, mDNSVal16(dstport), InterfaceID, msg->h.numQuestions, msg->h.numQuestions == 1 ? ", " : "s,", msg->h.numAnswers, msg->h.numAnswers == 1 ? ", " : "s,", msg->h.numAuthorities, msg->h.numAuthorities == 1 ? "y, " : "ies,", msg->h.numAdditionals, msg->h.numAdditionals == 1 ? " " : "s", end - msg->data); if (!InterfaceID || !m->SPSSocket || !mDNSSameIPPort(dstport, m->SPSSocket->port)) return; if (mDNS_PacketLoggingEnabled) DumpPacket(m, mStatus_NoError, mDNSfalse, "UDP", srcaddr, srcport, dstaddr, dstport, msg, end); ptr = LocateOptRR(msg, end, DNSOpt_LeaseData_Space + DNSOpt_OwnerData_ID_Space); if (ptr) { ptr = GetLargeResourceRecord(m, msg, ptr, end, 0, kDNSRecordTypePacketAdd, &m->rec); if (ptr && m->rec.r.resrec.RecordType != kDNSRecordTypePacketNegative && m->rec.r.resrec.rrtype == kDNSType_OPT) { const rdataOPT *o; const rdataOPT *const e = (const rdataOPT *)&m->rec.r.resrec.rdata->u.data[m->rec.r.resrec.rdlength]; for (o = &m->rec.r.resrec.rdata->u.opt[0]; o < e; o++) { if (o->opt == kDNSOpt_Lease) updatelease = o->u.updatelease; else if (o->opt == kDNSOpt_Owner && o->u.owner.vers == 0) owner = o->u.owner; } } m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it } InitializeDNSMessage(&m->omsg.h, msg->h.id, UpdateRespFlags); if (!updatelease || !owner.HMAC.l[0]) { static int msgs = 0; if (msgs < 100) { msgs++; LogMsg("Refusing sleep proxy registration from %#a:%d:%s%s", srcaddr, mDNSVal16(srcport), !updatelease ? " No lease" : "", !owner.HMAC.l[0] ? " No owner" : ""); } m->omsg.h.flags.b[1] |= kDNSFlag1_RC_FormErr; } else if (m->ProxyRecords + msg->h.mDNS_numUpdates > MAX_PROXY_RECORDS) { static int msgs = 0; if (msgs < 100) { msgs++; LogMsg("Refusing sleep proxy registration from %#a:%d: Too many records %d + %d = %d > %d", srcaddr, mDNSVal16(srcport), m->ProxyRecords, msg->h.mDNS_numUpdates, m->ProxyRecords + msg->h.mDNS_numUpdates, MAX_PROXY_RECORDS); } m->omsg.h.flags.b[1] |= kDNSFlag1_RC_Refused; } else { LogSPS("Received Update for H-MAC %.6a I-MAC %.6a Password %.6a seq %d", &owner.HMAC, &owner.IMAC, &owner.password, owner.seq); if (updatelease > 24 * 60 * 60) updatelease = 24 * 60 * 60; if (updatelease > 0x40000000UL / mDNSPlatformOneSecond) updatelease = 0x40000000UL / mDNSPlatformOneSecond; ptr = LocateAuthorities(msg, end); // Clear any stale TCP keepalive records that may exist ClearKeepaliveProxyRecords(m, &owner, m->DuplicateRecords, InterfaceID); ClearKeepaliveProxyRecords(m, &owner, m->ResourceRecords, InterfaceID); for (i = 0; i < msg->h.mDNS_numUpdates && ptr && ptr < end; i++) { ptr = GetLargeResourceRecord(m, msg, ptr, end, InterfaceID, kDNSRecordTypePacketAuth, &m->rec); if (ptr && m->rec.r.resrec.RecordType != kDNSRecordTypePacketNegative) { mDNSu16 RDLengthMem = GetRDLengthMem(&m->rec.r.resrec); AuthRecord *ar = mDNSPlatformMemAllocate(sizeof(AuthRecord) - sizeof(RDataBody) + RDLengthMem); if (!ar) { m->omsg.h.flags.b[1] |= kDNSFlag1_RC_Refused; break; } else { mDNSu8 RecordType = m->rec.r.resrec.RecordType & kDNSRecordTypePacketUniqueMask ? kDNSRecordTypeUnique : kDNSRecordTypeShared; m->rec.r.resrec.rrclass &= ~kDNSClass_UniqueRRSet; // All stale keepalive records have been flushed prior to this loop. if (!mDNS_KeepaliveRecord(&m->rec.r.resrec)) { ClearIdenticalProxyRecords(m, &owner, m->DuplicateRecords); // Make sure we don't have any old stale duplicates of this record ClearIdenticalProxyRecords(m, &owner, m->ResourceRecords); } mDNS_SetupResourceRecord(ar, mDNSNULL, InterfaceID, m->rec.r.resrec.rrtype, m->rec.r.resrec.rroriginalttl, RecordType, AuthRecordAny, SPSRecordCallback, ar); AssignDomainName(&ar->namestorage, m->rec.r.resrec.name); ar->resrec.rdlength = GetRDLength(&m->rec.r.resrec, mDNSfalse); ar->resrec.rdata->MaxRDLength = RDLengthMem; mDNSPlatformMemCopy(ar->resrec.rdata->u.data, m->rec.r.resrec.rdata->u.data, RDLengthMem); ar->ForceMCast = mDNStrue; ar->WakeUp = owner; if (m->rec.r.resrec.rrtype == kDNSType_PTR) { mDNSs32 t = ReverseMapDomainType(m->rec.r.resrec.name); if (t == mDNSAddrType_IPv4) GetIPv4FromName(&ar->AddressProxy, m->rec.r.resrec.name); else if (t == mDNSAddrType_IPv6) GetIPv6FromName(&ar->AddressProxy, m->rec.r.resrec.name); debugf("mDNSCoreReceiveUpdate: PTR %d %d %#a %s", t, ar->AddressProxy.type, &ar->AddressProxy, ARDisplayString(m, ar)); if (ar->AddressProxy.type) SetSPSProxyListChanged(InterfaceID); } ar->TimeRcvd = m->timenow; ar->TimeExpire = m->timenow + updatelease * mDNSPlatformOneSecond; if (m->NextScheduledSPS - ar->TimeExpire > 0) m->NextScheduledSPS = ar->TimeExpire; ar->KATimeExpire = 0; mDNS_Register_internal(m, ar); m->ProxyRecords++; mDNS_UpdateAllowSleep(m); LogSPS("SPS Registered %4d %X %s", m->ProxyRecords, RecordType, ARDisplayString(m,ar)); } } m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it } if (m->omsg.h.flags.b[1] & kDNSFlag1_RC_Mask) { LogMsg("Refusing sleep proxy registration from %#a:%d: Out of memory", srcaddr, mDNSVal16(srcport)); ClearProxyRecords(m, &owner, m->DuplicateRecords); ClearProxyRecords(m, &owner, m->ResourceRecords); } else { mDNS_SetupResourceRecord(&opt, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); opt.resrec.rrclass = NormalMaxDNSMessageData; opt.resrec.rdlength = sizeof(rdataOPT); // One option in this OPT record opt.resrec.rdestimate = sizeof(rdataOPT); opt.resrec.rdata->u.opt[0].opt = kDNSOpt_Lease; opt.resrec.rdata->u.opt[0].u.updatelease = updatelease; p = PutResourceRecordTTLWithLimit(&m->omsg, p, &m->omsg.h.numAdditionals, &opt.resrec, opt.resrec.rroriginalttl, m->omsg.data + AbsoluteMaxDNSMessageData); } } if (p) mDNSSendDNSMessage(m, &m->omsg, p, InterfaceID, m->SPSSocket, srcaddr, srcport, mDNSNULL, mDNSNULL, mDNSfalse); mDNS_SendKeepalives(m); } mDNSlocal mDNSu32 mDNSGenerateOwnerOptForInterface(mDNS *const m, const mDNSInterfaceID InterfaceID, DNSMessage *msg) { mDNSu8 *ptr = msg->data; mDNSu8 *end = mDNSNULL; mDNSu32 length = 0; AuthRecord opt; NetworkInterfaceInfo *intf; mDNS_SetupResourceRecord(&opt, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); opt.resrec.rrclass = NormalMaxDNSMessageData; opt.resrec.rdlength = sizeof(rdataOPT); opt.resrec.rdestimate = sizeof(rdataOPT); intf = FirstInterfaceForID(m, InterfaceID); SetupOwnerOpt(m, intf, &opt.resrec.rdata->u.opt[0]); LogSPS("Generated OPT record : %s", ARDisplayString(m, &opt)); end = PutResourceRecord(msg, ptr, &msg->h.numAdditionals, &opt.resrec); if (end != mDNSNULL) { // Put all the integer values in IETF byte-order (MSB first, LSB second) SwapDNSHeaderBytes(msg); length = (end - msg->data); } else LogSPS("mDNSGenerateOwnerOptForInterface: Failed to generate owner OPT record"); return length; } // Note that this routine is called both for Sleep Proxy Registrations, and for Standard Dynamic // DNS registrations, but (currently) only has to handle the Sleep Proxy Registration reply case, // and should ignore Standard Dynamic DNS registration replies, because those are handled elsewhere. // Really, both should be unified and handled in one place. mDNSlocal void mDNSCoreReceiveUpdateR(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *end, const mDNSAddr *srcaddr, const mDNSInterfaceID InterfaceID) { if (InterfaceID) { mDNSu32 pktlease = 0, spsupdates = 0; const mDNSBool gotlease = GetPktLease(m, msg, end, &pktlease); const mDNSu32 updatelease = gotlease ? pktlease : 60 * 60; // If SPS fails to indicate lease time, assume one hour if (gotlease) LogSPS("DNS Update response contains lease option granting %4d seconds, updateid %d, InterfaceID %p", updatelease, mDNSVal16(msg->h.id), InterfaceID); if (m->CurrentRecord) LogMsg("mDNSCoreReceiveUpdateR ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); m->CurrentRecord = m->ResourceRecords; while (m->CurrentRecord) { AuthRecord *const rr = m->CurrentRecord; if (rr->resrec.InterfaceID == InterfaceID || (!rr->resrec.InterfaceID && (rr->ForceMCast || IsLocalDomain(rr->resrec.name)))) if (mDNSSameOpaque16(rr->updateid, msg->h.id)) { // We successfully completed this record's registration on this "InterfaceID". Clear that bit. // Clear the updateid when we are done sending on all interfaces. mDNSu32 scopeid = mDNSPlatformInterfaceIndexfromInterfaceID(m, InterfaceID, mDNStrue); if (scopeid < (sizeof(rr->updateIntID) * mDNSNBBY)) bit_clr_opaque64(rr->updateIntID, scopeid); if (mDNSOpaque64IsZero(&rr->updateIntID)) rr->updateid = zeroID; rr->expire = NonZeroTime(m->timenow + updatelease * mDNSPlatformOneSecond); spsupdates++; LogSPS("Sleep Proxy %s record %2d %5d 0x%x 0x%x (%d) %s", rr->WakeUp.HMAC.l[0] ? "transferred" : "registered", spsupdates, updatelease, rr->updateIntID.l[1], rr->updateIntID.l[0], mDNSVal16(rr->updateid), ARDisplayString(m,rr)); if (rr->WakeUp.HMAC.l[0]) { rr->WakeUp.HMAC = zeroEthAddr; // Clear HMAC so that mDNS_Deregister_internal doesn't waste packets trying to wake this host rr->RequireGoodbye = mDNSfalse; // and we don't want to send goodbye for it mDNS_Deregister_internal(m, rr, mDNS_Dereg_normal); } } // Mustn't advance m->CurrentRecord until *after* mDNS_Deregister_internal, because // new records could have been added to the end of the list as a result of that call. if (m->CurrentRecord == rr) // If m->CurrentRecord was not advanced for us, do it now m->CurrentRecord = rr->next; } if (spsupdates) // Only do this dynamic store stuff if this was, in fact, a Sleep Proxy Update response { char *ifname; mDNSAddr spsaddr; DNSMessage optMsg; int length; // Update the dynamic store with the IP Address and MAC address of the sleep proxy ifname = InterfaceNameForID(m, InterfaceID); mDNSPlatformMemCopy(&spsaddr, srcaddr, sizeof (mDNSAddr)); mDNSPlatformStoreSPSMACAddr(&spsaddr, ifname); // Store the Owner OPT record for this interface. // Configd may use the OPT record if it detects a conflict with the BSP when the system wakes up InitializeDNSMessage(&optMsg.h, zeroID, ResponseFlags); length = mDNSGenerateOwnerOptForInterface(m, InterfaceID, &optMsg); if (length != 0) { length += sizeof(DNSMessageHeader); mDNSPlatformStoreOwnerOptRecord(ifname, &optMsg, length); } } } // If we were waiting to go to sleep, then this SPS registration or wide-area record deletion // may have been the thing we were waiting for, so schedule another check to see if we can sleep now. if (m->SleepLimit) m->NextScheduledSPRetry = m->timenow; } mDNSexport void MakeNegativeCacheRecord(mDNS *const m, CacheRecord *const cr, const domainname *const name, const mDNSu32 namehash, const mDNSu16 rrtype, const mDNSu16 rrclass, mDNSu32 ttl_seconds, mDNSInterfaceID InterfaceID, DNSServer *dnsserver) { if (cr == &m->rec.r && m->rec.r.resrec.RecordType) LogFatalError("MakeNegativeCacheRecord: m->rec appears to be already in use for %s", CRDisplayString(m, &m->rec.r)); // Create empty resource record cr->resrec.RecordType = kDNSRecordTypePacketNegative; cr->resrec.InterfaceID = InterfaceID; cr->resrec.rDNSServer = dnsserver; cr->resrec.name = name; // Will be updated to point to cg->name when we call CreateNewCacheEntry cr->resrec.rrtype = rrtype; cr->resrec.rrclass = rrclass; cr->resrec.rroriginalttl = ttl_seconds; cr->resrec.rdlength = 0; cr->resrec.rdestimate = 0; cr->resrec.namehash = namehash; cr->resrec.rdatahash = 0; cr->resrec.rdata = (RData*)&cr->smallrdatastorage; cr->resrec.rdata->MaxRDLength = 0; cr->NextInKAList = mDNSNULL; cr->TimeRcvd = m->timenow; cr->DelayDelivery = 0; cr->NextRequiredQuery = m->timenow; cr->LastUsed = m->timenow; cr->CRActiveQuestion = mDNSNULL; cr->UnansweredQueries = 0; cr->LastUnansweredTime = 0; cr->NextInCFList = mDNSNULL; cr->nsec = mDNSNULL; cr->soa = mDNSNULL; cr->CRDNSSECQuestion = 0; // Initialize to the basic one and the caller can set it to more // specific based on the response if any cr->responseFlags = ResponseFlags; } mDNSexport void mDNSCoreReceive(mDNS *const m, DNSMessage *const msg, const mDNSu8 *const end, const mDNSAddr *const srcaddr, const mDNSIPPort srcport, const mDNSAddr *dstaddr, const mDNSIPPort dstport, const mDNSInterfaceID InterfaceID) { mDNSInterfaceID ifid = InterfaceID; const mDNSu8 *const pkt = (mDNSu8 *)msg; const mDNSu8 StdQ = kDNSFlag0_QR_Query | kDNSFlag0_OP_StdQuery; const mDNSu8 StdR = kDNSFlag0_QR_Response | kDNSFlag0_OP_StdQuery; const mDNSu8 UpdQ = kDNSFlag0_QR_Query | kDNSFlag0_OP_Update; const mDNSu8 UpdR = kDNSFlag0_QR_Response | kDNSFlag0_OP_Update; mDNSu8 QR_OP; mDNSu8 *ptr = mDNSNULL; mDNSBool TLS = (dstaddr == (mDNSAddr *)1); // For debug logs: dstaddr = 0 means TCP; dstaddr = 1 means TLS if (TLS) dstaddr = mDNSNULL; #ifndef UNICAST_DISABLED if (mDNSSameAddress(srcaddr, &m->Router)) { #ifdef _LEGACY_NAT_TRAVERSAL_ if (mDNSSameIPPort(srcport, SSDPPort) || (m->SSDPSocket && mDNSSameIPPort(dstport, m->SSDPSocket->port))) { mDNS_Lock(m); LNT_ConfigureRouterInfo(m, InterfaceID, (mDNSu8 *)msg, (mDNSu16)(end - pkt)); mDNS_Unlock(m); return; } #endif if (mDNSSameIPPort(srcport, NATPMPPort)) { mDNS_Lock(m); uDNS_ReceiveNATPacket(m, InterfaceID, (mDNSu8 *)msg, (mDNSu16)(end - pkt)); mDNS_Unlock(m); return; } } #ifdef _LEGACY_NAT_TRAVERSAL_ else if (m->SSDPSocket && mDNSSameIPPort(dstport, m->SSDPSocket->port)) { debugf("Ignoring SSDP response from %#a:%d", srcaddr, mDNSVal16(srcport)); return; } #endif #endif if ((unsigned)(end - pkt) < sizeof(DNSMessageHeader)) { LogMsg("DNS Message from %#a:%d to %#a:%d length %d too short", srcaddr, mDNSVal16(srcport), dstaddr, mDNSVal16(dstport), (int)(end - pkt)); return; } QR_OP = (mDNSu8)(msg->h.flags.b[0] & kDNSFlag0_QROP_Mask); // Read the integer parts which are in IETF byte-order (MSB first, LSB second) ptr = (mDNSu8 *)&msg->h.numQuestions; msg->h.numQuestions = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); msg->h.numAnswers = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); msg->h.numAuthorities = (mDNSu16)((mDNSu16)ptr[4] << 8 | ptr[5]); msg->h.numAdditionals = (mDNSu16)((mDNSu16)ptr[6] << 8 | ptr[7]); if (!m) { LogMsg("mDNSCoreReceive ERROR m is NULL"); return; } // We use zero addresses and all-ones addresses at various places in the code to indicate special values like "no address" // If we accept and try to process a packet with zero or all-ones source address, that could really mess things up if (srcaddr && !mDNSAddressIsValid(srcaddr)) { debugf("mDNSCoreReceive ignoring packet from %#a", srcaddr); return; } mDNS_Lock(m); m->PktNum++; if (mDNSOpaque16IsZero(msg->h.id)) { m->MPktNum++; #if APPLE_OSX_mDNSResponder // Track the number of multicast packets received from a source outside our subnet. // Check the destination address to avoid accounting for spurious packets that // comes in with message id zero. if (!mDNS_AddressIsLocalSubnet(m, InterfaceID, srcaddr) && dstaddr && mDNSAddressIsAllDNSLinkGroup(dstaddr)) { m->RemoteSubnet++; } #endif // #if APPLE_OSX_mDNSResponder } #ifndef UNICAST_DISABLED if (!dstaddr || (!mDNSAddressIsAllDNSLinkGroup(dstaddr) && (QR_OP == StdR || QR_OP == UpdR))) if (!mDNSOpaque16IsZero(msg->h.id)) // uDNS_ReceiveMsg only needs to get real uDNS responses, not "QU" mDNS responses { ifid = mDNSInterface_Any; if (mDNS_PacketLoggingEnabled) DumpPacket(m, mStatus_NoError, mDNSfalse, TLS ? "TLS" : !dstaddr ? "TCP" : "UDP", srcaddr, srcport, dstaddr, dstport, msg, end); uDNS_ReceiveMsg(m, msg, end, srcaddr, srcport); // Note: mDNSCore also needs to get access to received unicast responses } #endif if (QR_OP == StdQ) mDNSCoreReceiveQuery (m, msg, end, srcaddr, srcport, dstaddr, dstport, ifid); else if (QR_OP == StdR) mDNSCoreReceiveResponse(m, msg, end, srcaddr, srcport, dstaddr, dstport, ifid); else if (QR_OP == UpdQ) mDNSCoreReceiveUpdate (m, msg, end, srcaddr, srcport, dstaddr, dstport, InterfaceID); else if (QR_OP == UpdR) mDNSCoreReceiveUpdateR (m, msg, end, srcaddr, InterfaceID); else { if (mDNS_LoggingEnabled) { static int msgCount = 0; if (msgCount < 1000) { int i = 0; msgCount++; LogInfo("Unknown DNS packet type %02X%02X from %#-15a:%-5d to %#-15a:%-5d length %d on %p (ignored)", msg->h.flags.b[0], msg->h.flags.b[1], srcaddr, mDNSVal16(srcport), dstaddr, mDNSVal16(dstport), (int)(end - pkt), InterfaceID); while (i < (int)(end - pkt)) { char buffer[128]; char *p = buffer + mDNS_snprintf(buffer, sizeof(buffer), "%04X", i); do if (i < (int)(end - pkt)) p += mDNS_snprintf(p, sizeof(buffer), " %02X", pkt[i]);while (++i & 15); LogInfo("%s", buffer); } } } } // Packet reception often causes a change to the task list: // 1. Inbound queries can cause us to need to send responses // 2. Conflicing response packets received from other hosts can cause us to need to send defensive responses // 3. Other hosts announcing deletion of shared records can cause us to need to re-assert those records // 4. Response packets that answer questions may cause our client to issue new questions mDNS_Unlock(m); } // *************************************************************************** #if COMPILER_LIKES_PRAGMA_MARK #pragma mark - #pragma mark - Searcher Functions #endif // Targets are considered the same if both queries are untargeted, or // if both are targeted to the same address+port // (If Target address is zero, TargetPort is undefined) #define SameQTarget(A,B) (((A)->Target.type == mDNSAddrType_None && (B)->Target.type == mDNSAddrType_None) || \ (mDNSSameAddress(& (A)->Target, & (B)->Target) && mDNSSameIPPort((A)->TargetPort, (B)->TargetPort))) // SameQuestionKind is true if *both* questions are either multicast or unicast // TargetQID is used for this determination. #define SameQuestionKind(A,B) ((mDNSOpaque16IsZero(A) && mDNSOpaque16IsZero(B)) || \ ((!mDNSOpaque16IsZero(A)) && (!mDNSOpaque16IsZero(B)))) // Note: We explicitly disallow making a public query be a duplicate of a private one. This is to avoid the // circular deadlock where a client does a query for something like "dns-sd -Q _dns-query-tls._tcp.company.com SRV" // and we have a key for company.com, so we try to locate the private query server for company.com, which necessarily entails // doing a standard DNS query for the _dns-query-tls._tcp SRV record for company.com. If we make the latter (public) query // a duplicate of the former (private) query, then it will block forever waiting for an answer that will never come. // // We keep SuppressUnusable questions separate so that we can return a quick response to them and not get blocked behind // the queries that are not marked SuppressUnusable. But if the query is not suppressed, they are treated the same as // non-SuppressUnusable questions. This should be fine as the goal of SuppressUnusable is to return quickly only if it // is suppressed. If it is not suppressed, we do try all the DNS servers for valid answers like any other question. // The main reason for this design is that cache entries point to a *single* question and that question is responsible // for keeping the cache fresh as long as it is active. Having multiple active question for a single cache entry // breaks this design principle. // // If IsLLQ(Q) is true, it means the question is both: // (a) long-lived and // (b) being performed by a unicast DNS long-lived query (either full LLQ, or polling) // for multicast questions, we don't want to treat LongLived as anything special #define IsLLQ(Q) ((Q)->LongLived && !mDNSOpaque16IsZero((Q)->TargetQID)) #define IsAWDLIncluded(Q) (((Q)->flags & kDNSServiceFlagsIncludeAWDL) != 0) mDNSlocal DNSQuestion *FindDuplicateQuestion(const mDNS *const m, const DNSQuestion *const question) { DNSQuestion *q; // Note: A question can only be marked as a duplicate of one that occurs *earlier* in the list. // This prevents circular references, where two questions are each marked as a duplicate of the other. // Accordingly, we break out of the loop when we get to 'question', because there's no point searching // further in the list. for (q = m->Questions; q && q != question; q=q->next) // Scan our list for another question if (q->InterfaceID == question->InterfaceID && // with the same InterfaceID, SameQTarget(q, question) && // and same unicast/multicast target settings q->qtype == question->qtype && // type, q->qclass == question->qclass && // class, IsLLQ(q) == IsLLQ(question) && // and long-lived status matches (!q->AuthInfo || question->AuthInfo) && // to avoid deadlock, don't make public query dup of a private one (q->AnonInfo == question->AnonInfo) && // Anonymous query not a dup of normal query (q->SuppressQuery == question->SuppressQuery) && // Questions that are suppressed/not suppressed (q->ValidationRequired == question->ValidationRequired) && // Questions that require DNSSEC validation (q->ValidatingResponse == question->ValidatingResponse) && // Questions that are validating responses using DNSSEC (q->DisallowPID == question->DisallowPID) && // Disallowing a PID should not affect a PID that is allowed (q->BrowseThreshold == question->BrowseThreshold) && // browse thresholds must match q->qnamehash == question->qnamehash && (IsAWDLIncluded(q) == IsAWDLIncluded(question)) && // Inclusion of AWDL interface must match SameQuestionKind(q->TargetQID, question->TargetQID) && // mDNS or uDNS must match SameDomainName(&q->qname, &question->qname)) // and name return(q); return(mDNSNULL); } // This is called after a question is deleted, in case other identical questions were being suppressed as duplicates mDNSlocal void UpdateQuestionDuplicates(mDNS *const m, DNSQuestion *const question) { DNSQuestion *q; DNSQuestion *first = mDNSNULL; // This is referring to some other question as duplicate. No other question can refer to this // question as a duplicate. if (question->DuplicateOf) { LogInfo("UpdateQuestionDuplicates: question %p %##s (%s) duplicate of %p %##s (%s)", question, question->qname.c, DNSTypeName(question->qtype), question->DuplicateOf, question->DuplicateOf->qname.c, DNSTypeName(question->DuplicateOf->qtype)); return; } for (q = m->Questions; q; q=q->next) // Scan our list of questions if (q->DuplicateOf == question) // To see if any questions were referencing this as their duplicate { q->DuplicateOf = first; if (!first) { first = q; // If q used to be a duplicate, but now is not, // then inherit the state from the question that's going away q->LastQTime = question->LastQTime; q->ThisQInterval = question->ThisQInterval; q->ExpectUnicastResp = question->ExpectUnicastResp; q->LastAnswerPktNum = question->LastAnswerPktNum; q->RecentAnswerPkts = question->RecentAnswerPkts; q->RequestUnicast = question->RequestUnicast; q->LastQTxTime = question->LastQTxTime; q->CNAMEReferrals = question->CNAMEReferrals; q->nta = question->nta; q->servAddr = question->servAddr; q->servPort = question->servPort; q->qDNSServer = question->qDNSServer; q->validDNSServers = question->validDNSServers; q->unansweredQueries = question->unansweredQueries; q->noServerResponse = question->noServerResponse; q->triedAllServersOnce = question->triedAllServersOnce; q->TargetQID = question->TargetQID; q->LocalSocket = question->LocalSocket; // No need to close old q->LocalSocket first -- duplicate questions can't have their own sockets q->state = question->state; // q->tcp = question->tcp; q->ReqLease = question->ReqLease; q->expire = question->expire; q->ntries = question->ntries; q->id = question->id; question->LocalSocket = mDNSNULL; question->nta = mDNSNULL; // If we've got a GetZoneData in progress, transfer it to the newly active question // question->tcp = mDNSNULL; if (q->LocalSocket) debugf("UpdateQuestionDuplicates transferred LocalSocket pointer for %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); if (q->nta) { LogInfo("UpdateQuestionDuplicates transferred nta pointer for %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); q->nta->ZoneDataContext = q; } // Need to work out how to safely transfer this state too -- appropriate context pointers need to be updated or the code will crash if (question->tcp) LogInfo("UpdateQuestionDuplicates did not transfer tcp pointer"); if (question->state == LLQ_Established) { LogInfo("UpdateQuestionDuplicates transferred LLQ state for %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); question->state = 0; // Must zero question->state, or mDNS_StopQuery_internal will clean up and cancel our LLQ from the server } SetNextQueryTime(m,q); } } } mDNSexport McastResolver *mDNS_AddMcastResolver(mDNS *const m, const domainname *d, const mDNSInterfaceID interface, mDNSu32 timeout) { McastResolver **p = &m->McastResolvers; McastResolver *tmp = mDNSNULL; if (!d) d = (const domainname *)""; LogInfo("mDNS_AddMcastResolver: Adding %##s, InterfaceID %p, timeout %u", d->c, interface, timeout); mDNS_CheckLock(m); while (*p) // Check if we already have this {interface, domain} tuple registered { if ((*p)->interface == interface && SameDomainName(&(*p)->domain, d)) { if (!((*p)->flags & McastResolver_FlagDelete)) LogMsg("Note: Mcast Resolver domain %##s (%p) registered more than once", d->c, interface); (*p)->flags &= ~McastResolver_FlagDelete; tmp = *p; *p = tmp->next; tmp->next = mDNSNULL; } else p=&(*p)->next; } if (tmp) *p = tmp; // move to end of list, to ensure ordering from platform layer else { // allocate, add to list *p = mDNSPlatformMemAllocate(sizeof(**p)); if (!*p) LogMsg("mDNS_AddMcastResolver: ERROR!! - malloc"); else { (*p)->interface = interface; (*p)->flags = McastResolver_FlagNew; (*p)->timeout = timeout; AssignDomainName(&(*p)->domain, d); (*p)->next = mDNSNULL; } } return(*p); } mDNSinline mDNSs32 PenaltyTimeForServer(mDNS *m, DNSServer *server) { mDNSs32 ptime = 0; if (server->penaltyTime != 0) { ptime = server->penaltyTime - m->timenow; if (ptime < 0) { // This should always be a positive value between 0 and DNSSERVER_PENALTY_TIME // If it does not get reset in ResetDNSServerPenalties for some reason, we do it // here LogMsg("PenaltyTimeForServer: PenaltyTime negative %d, (server penaltyTime %d, timenow %d) resetting the penalty", ptime, server->penaltyTime, m->timenow); server->penaltyTime = 0; ptime = 0; } } return ptime; } //Checks to see whether the newname is a better match for the name, given the best one we have //seen so far (given in bestcount). //Returns -1 if the newname is not a better match //Returns 0 if the newname is the same as the old match //Returns 1 if the newname is a better match mDNSlocal int BetterMatchForName(const domainname *name, int namecount, const domainname *newname, int newcount, int bestcount) { // If the name contains fewer labels than the new server's domain or the new name // contains fewer labels than the current best, then it can't possibly be a better match if (namecount < newcount || newcount < bestcount) return -1; // If there is no match, return -1 and the caller will skip this newname for // selection // // If we find a match and the number of labels is the same as bestcount, then // we return 0 so that the caller can do additional logic to pick one of // the best based on some other factors e.g., penaltyTime // // If we find a match and the number of labels is more than bestcount, then we // return 1 so that the caller can pick this over the old one. // // Note: newcount can either be equal or greater than bestcount beause of the // check above. if (SameDomainName(SkipLeadingLabels(name, namecount - newcount), newname)) return bestcount == newcount ? 0 : 1; else return -1; } // Normally, we have McastResolvers for .local, in-addr.arpa and ip6.arpa. But there // can be queries that can forced to multicast (ForceMCast) even though they don't end in these // names. In that case, we give a default timeout of 5 seconds #define DEFAULT_MCAST_TIMEOUT 5 mDNSlocal mDNSu32 GetTimeoutForMcastQuestion(mDNS *m, DNSQuestion *question) { McastResolver *curmatch = mDNSNULL; int bestmatchlen = -1, namecount = CountLabels(&question->qname); McastResolver *curr; int bettermatch, currcount; for (curr = m->McastResolvers; curr; curr = curr->next) { currcount = CountLabels(&curr->domain); bettermatch = BetterMatchForName(&question->qname, namecount, &curr->domain, currcount, bestmatchlen); // Take the first best match. If there are multiple equally good matches (bettermatch = 0), we take // the timeout value from the first one if (bettermatch == 1) { curmatch = curr; bestmatchlen = currcount; } } LogInfo("GetTimeoutForMcastQuestion: question %##s curmatch %p, Timeout %d", question->qname.c, curmatch, curmatch ? curmatch->timeout : DEFAULT_MCAST_TIMEOUT); return ( curmatch ? curmatch->timeout : DEFAULT_MCAST_TIMEOUT); } // Returns true if it is a Domain Enumeration Query mDNSexport mDNSBool DomainEnumQuery(const domainname *qname) { const mDNSu8 *mDNS_DEQLabels[] = { (const mDNSu8 *)"\001b", (const mDNSu8 *)"\002db", (const mDNSu8 *)"\002lb", (const mDNSu8 *)"\001r", (const mDNSu8 *)"\002dr", (const mDNSu8 *)mDNSNULL, }; const domainname *d = qname; const mDNSu8 *label; int i = 0; // We need at least 3 labels (DEQ prefix) + one more label to make a meaningful DE query if (CountLabels(qname) < 4) { debugf("DomainEnumQuery: question %##s, not enough labels", qname->c); return mDNSfalse; } label = (const mDNSu8 *)d; while (mDNS_DEQLabels[i] != (const mDNSu8 *)mDNSNULL) { if (SameDomainLabel(mDNS_DEQLabels[i], label)) {debugf("DomainEnumQuery: DEQ %##s, label1 match", qname->c); break;} i++; } if (mDNS_DEQLabels[i] == (const mDNSu8 *)mDNSNULL) { debugf("DomainEnumQuery: Not a DEQ %##s, label1 mismatch", qname->c); return mDNSfalse; } debugf("DomainEnumQuery: DEQ %##s, label1 match", qname->c); // CountLabels already verified the number of labels d = (const domainname *)(d->c + 1 + d->c[0]); // Second Label label = (const mDNSu8 *)d; if (!SameDomainLabel(label, (const mDNSu8 *)"\007_dns-sd")) { debugf("DomainEnumQuery: Not a DEQ %##s, label2 mismatch", qname->c); return(mDNSfalse); } debugf("DomainEnumQuery: DEQ %##s, label2 match", qname->c); d = (const domainname *)(d->c + 1 + d->c[0]); // Third Label label = (const mDNSu8 *)d; if (!SameDomainLabel(label, (const mDNSu8 *)"\004_udp")) { debugf("DomainEnumQuery: Not a DEQ %##s, label3 mismatch", qname->c); return(mDNSfalse); } debugf("DomainEnumQuery: DEQ %##s, label3 match", qname->c); debugf("DomainEnumQuery: Question %##s is a Domain Enumeration query", qname->c); return mDNStrue; } // Note: InterfaceID is the InterfaceID of the question mDNSlocal mDNSBool DNSServerMatch(DNSServer *d, mDNSInterfaceID InterfaceID, mDNSs32 ServiceID) { // 1) Unscoped questions (NULL InterfaceID) should consider *only* unscoped DNSServers ( DNSServer // with "scoped" set to kScopeNone) // // 2) Scoped questions (non-NULL InterfaceID) should consider *only* scoped DNSServers (DNSServer // with "scoped" set to kScopeInterfaceId) and their InterfaceIDs should match. // // 3) Scoped questions (non-zero ServiceID) should consider *only* scoped DNSServers (DNSServer // with "scoped" set to kScopeServiceID) and their ServiceIDs should match. // // The first condition in the "if" statement checks to see if both the question and the DNSServer are // unscoped. The question is unscoped only if InterfaceID is zero and ServiceID is -1. // // If the first condition fails, following are the possible cases (the notes below are using // InterfaceID for discussion and the same holds good for ServiceID): // // - DNSServer is not scoped, InterfaceID is not NULL - we should skip the current DNSServer entry // as scoped questions should not pick non-scoped DNSServer entry (Refer to (2) above). // // - DNSServer is scoped, InterfaceID is NULL - we should skip the current DNSServer entry as // unscoped question should not match scoped DNSServer (Refer to (1) above). The InterfaceID check // would fail in this case. // // - DNSServer is scoped and InterfaceID is not NULL - the InterfaceID of the question and the DNSServer // should match (Refer to (2) above). // // Note: mDNSInterface_Unicast is used only by .local unicast questions and are treated as unscoped. // If a question is scoped both to InterfaceID and ServiceID, the question will be scoped to InterfaceID. if (((d->scoped == kScopeNone) && ((!InterfaceID && ServiceID == -1) || InterfaceID == mDNSInterface_Unicast)) || ((d->scoped == kScopeInterfaceID) && d->interface == InterfaceID) || ((d->scoped == kScopeServiceID) && d->serviceID == ServiceID)) { return mDNStrue; } return mDNSfalse; } // Sets all the Valid DNS servers for a question mDNSexport mDNSu32 SetValidDNSServers(mDNS *m, DNSQuestion *question) { int bestmatchlen = -1, namecount = CountLabels(&question->qname); DNSServer *curr; int bettermatch, currcount; int index = 0; mDNSu32 timeout = 0; mDNSBool DEQuery; question->validDNSServers = zeroOpaque128; DEQuery = DomainEnumQuery(&question->qname); for (curr = m->DNSServers; curr; curr = curr->next) { debugf("SetValidDNSServers: Parsing DNS server Address %#a (Domain %##s), Scope: %d", &curr->addr, curr->domain.c, curr->scoped); // skip servers that will soon be deleted if (curr->flags & DNSServer_FlagDelete) { debugf("SetValidDNSServers: Delete set for index %d, DNS server %#a (Domain %##s), scoped %d", index, &curr->addr, curr->domain.c, curr->scoped); continue; } // This happens normally when you unplug the interface where we reset the interfaceID to mDNSInterface_Any for all // the DNS servers whose scope match the interfaceID. Few seconds later, we also receive the updated DNS configuration. // But any questions that has mDNSInterface_Any scope that are started/restarted before we receive the update // (e.g., CheckSuppressUnusableQuestions is called when interfaces are deregistered with the core) should not // match the scoped entries by mistake. // // Note: DNS configuration change will help pick the new dns servers but currently it does not affect the timeout // Skip DNSServers that are InterfaceID Scoped but have no valid interfaceid set OR DNSServers that are ServiceID Scoped but have no valid serviceid set if ((curr->scoped == kScopeInterfaceID && curr->interface == mDNSInterface_Any) || (curr->scoped == kScopeServiceID && curr->serviceID <= 0)) { LogInfo("SetValidDNSServers: ScopeType[%d] Skipping DNS server %#a (Domain %##s) Interface:[%p] Serviceid:[%d]", curr->scoped, &curr->addr, curr->domain.c, curr->interface, curr->serviceID); continue; } currcount = CountLabels(&curr->domain); if ((!curr->cellIntf || (!DEQuery && !(question->flags & kDNSServiceFlagsDenyCellular))) && (!curr->isExpensive || !(question->flags & kDNSServiceFlagsDenyExpensive)) && DNSServerMatch(curr, question->InterfaceID, question->ServiceID)) { bettermatch = BetterMatchForName(&question->qname, namecount, &curr->domain, currcount, bestmatchlen); // If we found a better match (bettermatch == 1) then clear all the bits // corresponding to the old DNSServers that we have may set before and start fresh. // If we find an equal match, then include that DNSServer also by setting the corresponding // bit if ((bettermatch == 1) || (bettermatch == 0)) { bestmatchlen = currcount; if (bettermatch) { debugf("SetValidDNSServers: Resetting all the bits"); question->validDNSServers = zeroOpaque128; timeout = 0; } debugf("SetValidDNSServers: question %##s Setting the bit for DNS server Address %#a (Domain %##s), Scoped:%d index %d," " Timeout %d, interface %p", question->qname.c, &curr->addr, curr->domain.c, curr->scoped, index, curr->timeout, curr->interface); timeout += curr->timeout; if (DEQuery) debugf("DomainEnumQuery: Question %##s, DNSServer %#a, cell %d", question->qname.c, &curr->addr, curr->cellIntf); bit_set_opaque128(question->validDNSServers, index); } } index++; } question->noServerResponse = 0; debugf("SetValidDNSServers: ValidDNSServer bits 0x%x%x%x%x for question %p %##s (%s)", question->validDNSServers.l[3], question->validDNSServers.l[2], question->validDNSServers.l[1], question->validDNSServers.l[0], question, question->qname.c, DNSTypeName(question->qtype)); // If there are no matching resolvers, then use the default timeout value. // For ProxyQuestion, shorten the timeout so that dig does not timeout on us in case of no response. return ((question->ProxyQuestion || question->ValidatingResponse) ? DEFAULT_UDNSSEC_TIMEOUT : timeout ? timeout : DEFAULT_UDNS_TIMEOUT); } // Get the Best server that matches a name. If you find penalized servers, look for the one // that will come out of the penalty box soon mDNSlocal DNSServer *GetBestServer(mDNS *m, const domainname *name, mDNSInterfaceID InterfaceID, mDNSs32 ServiceID, mDNSOpaque128 validBits, int *selected, mDNSBool nameMatch) { DNSServer *curmatch = mDNSNULL; int bestmatchlen = -1, namecount = name ? CountLabels(name) : 0; DNSServer *curr; mDNSs32 bestPenaltyTime, currPenaltyTime; int bettermatch, currcount; int index = 0; int currindex = -1; debugf("GetBestServer: ValidDNSServer bits 0x%x%x", validBits.l[1], validBits.l[0]); bestPenaltyTime = DNSSERVER_PENALTY_TIME + 1; for (curr = m->DNSServers; curr; curr = curr->next) { // skip servers that will soon be deleted if (curr->flags & DNSServer_FlagDelete) { debugf("GetBestServer: Delete set for index %d, DNS server %#a (Domain %##s), scoped %d", index, &curr->addr, curr->domain.c, curr->scoped); continue; } // Check if this is a valid DNSServer if (!bit_get_opaque64(validBits, index)) { debugf("GetBestServer: continuing for index %d", index); index++; continue; } currcount = CountLabels(&curr->domain); currPenaltyTime = PenaltyTimeForServer(m, curr); debugf("GetBestServer: Address %#a (Domain %##s), PenaltyTime(abs) %d, PenaltyTime(rel) %d", &curr->addr, curr->domain.c, curr->penaltyTime, currPenaltyTime); // If there are multiple best servers for a given question, we will pick the first one // if none of them are penalized. If some of them are penalized in that list, we pick // the least penalized one. BetterMatchForName walks through all best matches and // "currPenaltyTime < bestPenaltyTime" check lets us either pick the first best server // in the list when there are no penalized servers and least one among them // when there are some penalized servers. if (DNSServerMatch(curr, InterfaceID, ServiceID)) { // If we know that all the names are already equally good matches, then skip calling BetterMatchForName. // This happens when we initially walk all the DNS servers and set the validity bit on the question. // Actually we just need PenaltyTime match, but for the sake of readability we just skip the expensive // part and still do some redundant steps e.g., InterfaceID match if (nameMatch) bettermatch = BetterMatchForName(name, namecount, &curr->domain, currcount, bestmatchlen); else bettermatch = 0; // If we found a better match (bettermatch == 1) then we don't need to // compare penalty times. But if we found an equal match, then we compare // the penalty times to pick a better match if ((bettermatch == 1) || ((bettermatch == 0) && currPenaltyTime < bestPenaltyTime)) { currindex = index; curmatch = curr; bestmatchlen = currcount; bestPenaltyTime = currPenaltyTime; } } index++; } if (selected) *selected = currindex; return curmatch; } // Look up a DNS Server, matching by name and InterfaceID mDNSlocal DNSServer *GetServerForName(mDNS *m, const domainname *name, mDNSInterfaceID InterfaceID, mDNSs32 ServiceID) { DNSServer *curmatch = mDNSNULL; char *ifname = mDNSNULL; // for logging purposes only mDNSOpaque128 allValid; if ((InterfaceID == mDNSInterface_Unicast) || (InterfaceID == mDNSInterface_LocalOnly)) InterfaceID = mDNSNULL; if (InterfaceID) ifname = InterfaceNameForID(m, InterfaceID); // By passing in all ones, we make sure that every DNS server is considered allValid.l[0] = allValid.l[1] = allValid.l[2] = allValid.l[3] = 0xFFFFFFFF; curmatch = GetBestServer(m, name, InterfaceID, ServiceID, allValid, mDNSNULL, mDNStrue); if (curmatch != mDNSNULL) LogInfo("GetServerForName: DNS server %#a:%d (Penalty Time Left %d) (Scope %s:%p) found for name %##s", &curmatch->addr, mDNSVal16(curmatch->port), (curmatch->penaltyTime ? (curmatch->penaltyTime - m->timenow) : 0), ifname ? ifname : "None", InterfaceID, name); else LogInfo("GetServerForName: no DNS server (Scope %s:%p) found for name %##s", ifname ? ifname : "None", InterfaceID, name); return(curmatch); } // Look up a DNS Server for a question within its valid DNSServer bits mDNSexport DNSServer *GetServerForQuestion(mDNS *m, DNSQuestion *question) { DNSServer *curmatch = mDNSNULL; char *ifname = mDNSNULL; // for logging purposes only mDNSInterfaceID InterfaceID = question->InterfaceID; const domainname *name = &question->qname; int currindex; if ((InterfaceID == mDNSInterface_Unicast) || (InterfaceID == mDNSInterface_LocalOnly)) InterfaceID = mDNSNULL; if (InterfaceID) ifname = InterfaceNameForID(m, InterfaceID); if (!mDNSOpaque128IsZero(&question->validDNSServers)) { curmatch = GetBestServer(m, name, InterfaceID, question->ServiceID, question->validDNSServers, &currindex, mDNSfalse); if (currindex != -1) bit_clr_opaque128(question->validDNSServers, currindex); } if (curmatch != mDNSNULL) { LogInfo("GetServerForQuestion: %p DNS server (%p) %#a:%d (Penalty Time Left %d) (Scope %s:%p:%d) found for name %##s (%s)", question, curmatch, &curmatch->addr, mDNSVal16(curmatch->port), (curmatch->penaltyTime ? (curmatch->penaltyTime - m->timenow) : 0), ifname ? ifname : "None", InterfaceID, question->ServiceID, name, DNSTypeName(question->qtype)); } else { LogInfo("GetServerForQuestion: %p no DNS server (Scope %s:%p:%d) found for name %##s (%s)", question, ifname ? ifname : "None", InterfaceID, question->ServiceID, name, DNSTypeName(question->qtype)); } return(curmatch); } #define ValidQuestionTarget(Q) (((Q)->Target.type == mDNSAddrType_IPv4 || (Q)->Target.type == mDNSAddrType_IPv6) && \ (mDNSSameIPPort((Q)->TargetPort, UnicastDNSPort) || mDNSSameIPPort((Q)->TargetPort, MulticastDNSPort))) // Called in normal client context (lock not held) mDNSlocal void LLQNATCallback(mDNS *m, NATTraversalInfo *n) { DNSQuestion *q; mDNS_Lock(m); LogInfo("LLQNATCallback external address:port %.4a:%u, NAT result %d", &n->ExternalAddress, mDNSVal16(n->ExternalPort), n->Result); n->clientContext = mDNSNULL; // we received at least one callback since starting this NAT-T for (q = m->Questions; q; q=q->next) if (ActiveQuestion(q) && !mDNSOpaque16IsZero(q->TargetQID) && q->LongLived) startLLQHandshake(m, q); // If ExternalPort is zero, will do StartLLQPolling instead #if APPLE_OSX_mDNSResponder UpdateAutoTunnelDomainStatuses(m); #endif mDNS_Unlock(m); } mDNSlocal mDNSBool IsPrivateDomain(mDNS *const m, DNSQuestion *q) { DomainAuthInfo *AuthInfo; // Skip Private domains as we have special addresses to get the hosts in the Private domain AuthInfo = GetAuthInfoForName_internal(m, &q->qname); if (AuthInfo && !AuthInfo->deltime && AuthInfo->AutoTunnel) { debugf("IsPrivateDomain: %##s true", q->qname.c); return mDNStrue; } else { debugf("IsPrivateDomain: %##s false", q->qname.c); return mDNSfalse; } } // This function takes the DNSServer as a separate argument because sometimes the // caller has not yet assigned the DNSServer, but wants to evaluate the SuppressQuery // status before switching to it. mDNSlocal mDNSBool ShouldSuppressUnicastQuery(mDNS *const m, DNSQuestion *q, DNSServer *d) { // Some callers don't check for the qtype if (q->qtype != kDNSType_A && q->qtype != kDNSType_AAAA) { LogInfo("ShouldSuppressUnicastQuery: Query not suppressed for %##s, qtype %s, not A/AAAA type", q->qname.c, DNSTypeName(q->qtype)); return mDNSfalse; } // Private domains are exempted irrespective of what the DNSServer says if (IsPrivateDomain(m, q)) { LogInfo("ShouldSuppressUnicastQuery: Query not suppressed for %##s, qtype %s, Private Domain", q->qname.c, DNSTypeName(q->qtype)); return mDNSfalse; } if (!d) { LogInfo("ShouldSuppressUnicastQuery: Query suppressed for %##s, qtype %s, as the DNS server is NULL", q->qname.c, DNSTypeName(q->qtype)); return mDNStrue; } // Check if the DNS Configuration allows A/AAAA queries to be sent if ((q->qtype == kDNSType_A) && (d->req_A)) { LogInfo("ShouldSuppressUnicastQuery: Query not suppressed for %##s, qtype %s, DNSServer %##s %#a:%d allows A queries", q->qname.c, DNSTypeName(q->qtype), d->domain.c, &d->addr, mDNSVal16(d->port)); return mDNSfalse; } if ((q->qtype == kDNSType_AAAA) && (d->req_AAAA)) { LogInfo("ShouldSuppressUnicastQuery: Query not suppressed for %##s, qtype %s, DNSServer %##s %#a:%d allows AAAA queries", q->qname.c, DNSTypeName(q->qtype), d->domain.c, &d->addr, mDNSVal16(d->port)); return mDNSfalse; } #if USE_DNS64 if (DNS64IsQueryingARecord(q->dns64.state)) { LogInfo("ShouldSuppressUnicastQuery: DNS64 query not suppressed for %##s, qtype %s", q->qname.c, DNSTypeName(q->qtype)); return mDNSfalse; } #endif LogInfo("ShouldSuppressUnicastQuery: Query suppressed for %##s, qtype %s, since DNS Configuration does not allow (req_A is %s and req_AAAA is %s)", q->qname.c, DNSTypeName(q->qtype), d->req_A ? "true" : "false", d->req_AAAA ? "true" : "false"); return mDNStrue; } mDNSlocal mDNSBool ShouldSuppressDotLocalQuery(mDNS *const m, DNSQuestion *q) { NetworkInterfaceInfo *intf; AuthRecord *rr; mDNSBool ret; // Check to see if there is at least one interface other than loopback and don't suppress // .local questions if you find one. If we have at least one interface, it means that // we can send unicast queries for the .local name and we don't want to suppress // multicast in that case as upper layers don't know how to handle if we return a // negative response for multicast followed by a positive response for unicast. // // Note: we used to check for multicast capable interfaces instead of just any interface // present. That did not work in the case where we have a valid interface for unicast // but not multicast capable e.g., cellular, as we ended up delivering a negative response // first and the upper layer did not wait for the positive response that came later. for (intf = m->HostInterfaces; intf; intf = intf->next) { if (intf->InterfaceActive && !intf->Loopback) { LogInfo("ShouldSuppressDotLocalQuery: Found interface %s, not suppressing", intf->ifname); return mDNSfalse; } } // 1. If we find a LocalOnly or P2P record answering this question, then don't suppress it. // Set m->CurrentQuestion as it is required by AnswerQuestionWithLORecord. m->CurrentQuestion = q; ret = AnswerQuestionWithLORecord(m, q, mDNStrue); m->CurrentQuestion = mDNSNULL; if (ret) { LogInfo("ShouldSuppressDotLocalQuery: Found LocalOnly record for %##s (%s), not suppressing", q->qname.c, DNSTypeName(q->qtype)); return mDNSfalse; } // 2. If we find a local AuthRecord answering this question, then don't suppress it. for (rr = m->ResourceRecords; rr; rr = rr->next) { if (ResourceRecordAnswersQuestion(&rr->resrec, q)) { LogInfo("ShouldSuppressDotLocalQuery: Found resource record %s for %##s (%s) not suppressing", ARDisplayString(m, rr), q->qname.c, DNSTypeName(q->qtype)); return mDNSfalse; } } return mDNStrue; } mDNSlocal mDNSBool ShouldSuppressQuery(mDNS *const m, DNSQuestion *q) { if (q->InterfaceID == mDNSInterface_LocalOnly) { LogInfo("ShouldSuppressQuery: LocalOnly query not suppressed for %##s, qtype %s", q->qname.c, DNSTypeName(q->qtype)); return mDNSfalse; } if (q->qtype != kDNSType_A && q->qtype != kDNSType_AAAA) { LogInfo("ShouldSuppressQuery: Query not suppressed for %##s, qtype %s, not A/AAAA type", q->qname.c, DNSTypeName(q->qtype)); return mDNSfalse; } // We still want the ability to be able to listen to the local services and hence // don't fail .local query if we have local records that can potentially answer // the question. if (q->InterfaceID != mDNSInterface_Unicast && IsLocalDomain(&q->qname)) { if (!ShouldSuppressDotLocalQuery(m, q)) { LogInfo("ShouldSuppressQuery: Query not suppressed for %##s, qtype %s, Local question", q->qname.c, DNSTypeName(q->qtype)); return mDNSfalse; } else { LogInfo("ShouldSuppressQuery: Query suppressed for %##s, qtype %s, Local question", q->qname.c, DNSTypeName(q->qtype)); return mDNStrue; } } return (ShouldSuppressUnicastQuery(m, q, q->qDNSServer)); } mDNSlocal void CacheRecordRmvEventsForCurrentQuestion(mDNS *const m, DNSQuestion *q) { CacheRecord *rr; CacheGroup *cg; cg = CacheGroupForName(m, q->qnamehash, &q->qname); for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) { // Don't deliver RMV events for negative records if (rr->resrec.RecordType == kDNSRecordTypePacketNegative) { LogInfo("CacheRecordRmvEventsForCurrentQuestion: CacheRecord %s Suppressing RMV events for question %p %##s (%s), CRActiveQuestion %p, CurrentAnswers %d", CRDisplayString(m, rr), q, q->qname.c, DNSTypeName(q->qtype), rr->CRActiveQuestion, q->CurrentAnswers); continue; } if (SameNameRecordAnswersQuestion(&rr->resrec, q)) { LogInfo("CacheRecordRmvEventsForCurrentQuestion: Calling AnswerCurrentQuestionWithResourceRecord (RMV) for question %##s using resource record %s LocalAnswers %d", q->qname.c, CRDisplayString(m, rr), q->LOAddressAnswers); q->CurrentAnswers--; if (rr->resrec.rdlength > SmallRecordLimit) q->LargeAnswers--; if (rr->resrec.RecordType & kDNSRecordTypePacketUniqueMask) q->UniqueAnswers--; if (rr->CRActiveQuestion == q) { DNSQuestion *qptr; // If this was the active question for this cache entry, it was the one that was // responsible for keeping the cache entry fresh when the cache entry was reaching // its expiry. We need to handover the responsibility to someone else. Otherwise, // when the cache entry is about to expire, we won't find an active question // (pointed by CRActiveQuestion) to refresh the cache. for (qptr = m->Questions; qptr; qptr=qptr->next) if (qptr != q && ActiveQuestion(qptr) && ResourceRecordAnswersQuestion(&rr->resrec, qptr)) break; if (qptr) LogInfo("CacheRecordRmvEventsForCurrentQuestion: Updating CRActiveQuestion to %p for cache record %s, " "Original question CurrentAnswers %d, new question CurrentAnswers %d, SuppressUnusable %d, SuppressQuery %d", qptr, CRDisplayString(m,rr), q->CurrentAnswers, qptr->CurrentAnswers, qptr->SuppressUnusable, qptr->SuppressQuery); rr->CRActiveQuestion = qptr; // Question used to be active; new value may or may not be null if (!qptr) m->rrcache_active--; // If no longer active, decrement rrcache_active count } AnswerCurrentQuestionWithResourceRecord(m, rr, QC_rmv); if (m->CurrentQuestion != q) break; // If callback deleted q, then we're finished here } } } mDNSlocal mDNSBool IsQuestionNew(mDNS *const m, DNSQuestion *question) { DNSQuestion *q; for (q = m->NewQuestions; q; q = q->next) if (q == question) return mDNStrue; return mDNSfalse; } mDNSlocal mDNSBool LocalRecordRmvEventsForQuestion(mDNS *const m, DNSQuestion *q) { AuthRecord *rr; AuthGroup *ag; if (m->CurrentQuestion) LogMsg("LocalRecordRmvEventsForQuestion: ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); if (IsQuestionNew(m, q)) { LogInfo("LocalRecordRmvEventsForQuestion: New Question %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); return mDNStrue; } m->CurrentQuestion = q; ag = AuthGroupForName(&m->rrauth, q->qnamehash, &q->qname); if (ag) { for (rr = ag->members; rr; rr=rr->next) // Filter the /etc/hosts records - LocalOnly, Unique, A/AAAA/CNAME if (UniqueLocalOnlyRecord(rr) && LocalOnlyRecordAnswersQuestion(rr, q)) { LogInfo("LocalRecordRmvEventsForQuestion: Delivering possible Rmv events with record %s", ARDisplayString(m, rr)); if (q->CurrentAnswers <= 0 || q->LOAddressAnswers <= 0) { LogMsg("LocalRecordRmvEventsForQuestion: ERROR!! CurrentAnswers or LOAddressAnswers is zero %p %##s" " (%s) CurrentAnswers %d, LOAddressAnswers %d", q, q->qname.c, DNSTypeName(q->qtype), q->CurrentAnswers, q->LOAddressAnswers); continue; } AnswerLocalQuestionWithLocalAuthRecord(m, rr, QC_rmv); // MUST NOT dereference q again if (m->CurrentQuestion != q) { m->CurrentQuestion = mDNSNULL; return mDNSfalse; } } } m->CurrentQuestion = mDNSNULL; return mDNStrue; } // Returns false if the question got deleted while delivering the RMV events // The caller should handle the case mDNSexport mDNSBool CacheRecordRmvEventsForQuestion(mDNS *const m, DNSQuestion *q) { if (m->CurrentQuestion) LogMsg("CacheRecordRmvEventsForQuestion: ERROR m->CurrentQuestion already set: %##s (%s)", m->CurrentQuestion->qname.c, DNSTypeName(m->CurrentQuestion->qtype)); // If it is a new question, we have not delivered any ADD events yet. So, don't deliver RMV events. // If this question was answered using local auth records, then you can't deliver RMVs using cache if (!IsQuestionNew(m, q) && !q->LOAddressAnswers) { m->CurrentQuestion = q; CacheRecordRmvEventsForCurrentQuestion(m, q); if (m->CurrentQuestion != q) { m->CurrentQuestion = mDNSNULL; return mDNSfalse; } m->CurrentQuestion = mDNSNULL; } else { LogInfo("CacheRecordRmvEventsForQuestion: Question %p %##s (%s) is a new question", q, q->qname.c, DNSTypeName(q->qtype)); } return mDNStrue; } mDNSlocal void SuppressStatusChanged(mDNS *const m, DNSQuestion *q, DNSQuestion **restart) { // NOTE: CacheRecordRmvEventsForQuestion will not generate RMV events for queries that have non-zero // LOAddressAnswers. Hence it is important that we call CacheRecordRmvEventsForQuestion before // LocalRecordRmvEventsForQuestion (which decrements LOAddressAnswers) if (q->SuppressQuery) { q->SuppressQuery = mDNSfalse; if (!CacheRecordRmvEventsForQuestion(m, q)) { LogInfo("SuppressStatusChanged: Question deleted while delivering RMV events from cache"); return; } q->SuppressQuery = mDNStrue; } // SuppressUnusable does not affect questions that are answered from the local records (/etc/hosts) // and SuppressQuery status does not mean anything for these questions. As we are going to stop the // question below, we need to deliver the RMV events so that the ADDs that will be delivered during // the restart will not be a duplicate ADD if (!LocalRecordRmvEventsForQuestion(m, q)) { LogInfo("SuppressStatusChanged: Question deleted while delivering RMV events from Local AuthRecords"); return; } // There are two cases here. // // 1. Previously it was suppressed and now it is not suppressed, restart the question so // that it will start as a new question. Note that we can't just call ActivateUnicastQuery // because when we get the response, if we had entries in the cache already, it will not answer // this question if the cache entry did not change. Hence, we need to restart // the query so that it can be answered from the cache. // // 2. Previously it was not suppressed and now it is suppressed. We need to restart the questions // so that we redo the duplicate checks in mDNS_StartQuery_internal. A SuppressUnusable question // is a duplicate of non-SuppressUnusable question if it is not suppressed (SuppressQuery is false). // A SuppressUnusable question is not a duplicate of non-SuppressUnusable question if it is suppressed // (SuppressQuery is true). The reason for this is that when a question is suppressed, we want an // immediate response and not want to be blocked behind a question that is querying DNS servers. When // the question is not suppressed, we don't want two active questions sending packets on the wire. // This affects both efficiency and also the current design where there is only one active question // pointed to from a cache entry. // // We restart queries in a two step process by first calling stop and build a temporary list which we // will restart at the end. The main reason for the two step process is to handle duplicate questions. // If there are duplicate questions, calling stop inherits the values from another question on the list (which // will soon become the real question) including q->ThisQInterval which might be zero if it was // suppressed before. At the end when we have restarted all questions, none of them is active as each // inherits from one another and we need to reactivate one of the questions here which is a little hacky. // // It is much cleaner and less error prone to build a list of questions and restart at the end. LogInfo("SuppressStatusChanged: Stop question %p %##s (%s)", q, q->qname.c, DNSTypeName(q->qtype)); mDNS_StopQuery_internal(m, q); q->next = *restart; *restart = q; } // The caller should hold the lock mDNSexport void CheckSuppressUnusableQuestions(mDNS *const m) { DNSQuestion *q; DNSQuestion *restart = mDNSNULL; // We look through all questions including new questions. During network change events, // we potentially restart questions here in this function that ends up as new questions, // which may be suppressed at this instance. Before it is handled we get another network // event that changes the status e.g., address becomes available. If we did not process // new questions, we would never change its SuppressQuery status. // // CurrentQuestion is used by RmvEventsForQuestion below. While delivering RMV events, the // application callback can potentially stop the current question (detected by CurrentQuestion) or // *any* other question which could be the next one that we may process here. RestartQuestion // points to the "next" question which will be automatically advanced in mDNS_StopQuery_internal // if the "next" question is stopped while the CurrentQuestion is stopped if (m->RestartQuestion) LogMsg("CheckSuppressUnusableQuestions: ERROR!! m->RestartQuestion already set: %##s (%s)", m->RestartQuestion->qname.c, DNSTypeName(m->RestartQuestion->qtype)); m->RestartQuestion = m->Questions; while (m->RestartQuestion) { q = m->RestartQuestion; m->RestartQuestion = q->next; if (q->SuppressUnusable) { mDNSBool old = q->SuppressQuery; q->SuppressQuery = ShouldSuppressQuery(m, q); if (q->SuppressQuery != old) { // Previously it was not suppressed, Generate RMV events for the ADDs that we might have delivered before // followed by a negative cache response. Temporarily turn off suppression so that // AnswerCurrentQuestionWithResourceRecord can answer the question SuppressStatusChanged(m, q, &restart); } } } while (restart) { q = restart; restart = restart->next; q->next = mDNSNULL; LogInfo("CheckSuppressUnusableQuestions: Start question %p %##s (%s)", q, q->qname.c, DNSTypeName(q->qtype)); mDNS_StartQuery_internal(m, q); } } mDNSlocal void RestartUnicastQuestions(mDNS *const m) { DNSQuestion *q; DNSQuestion *restart = mDNSNULL; if (m->RestartQuestion) LogMsg("RestartUnicastQuestions: ERROR!! m->RestartQuestion already set: %##s (%s)", m->RestartQuestion->qname.c, DNSTypeName(m->RestartQuestion->qtype)); m->RestartQuestion = m->Questions; while (m->RestartQuestion) { q = m->RestartQuestion; m->RestartQuestion = q->next; if (q->Restart) { if (mDNSOpaque16IsZero(q->TargetQID)) LogMsg("RestartUnicastQuestions: ERROR!! Restart set for multicast question %##s (%s)", q->qname.c, DNSTypeName(q->qtype)); q->Restart = 0; SuppressStatusChanged(m, q, &restart); } } while (restart) { q = restart; restart = restart->next; q->next = mDNSNULL; LogInfo("RestartUnicastQuestions: Start question %p %##s (%s)", q, q->qname.c, DNSTypeName(q->qtype)); mDNS_StartQuery_internal(m, q); } } // ValidateParameters() is called by mDNS_StartQuery_internal() to check the client parameters of // DNS Question that are already set by the client before calling mDNS_StartQuery() mDNSlocal mStatus ValidateParameters(mDNS *const m, DNSQuestion *const question) { if (question->Target.type && !ValidQuestionTarget(question)) { LogMsg("ValidateParameters: Warning! Target.type = %ld port = %u (Client forgot to initialize before calling mDNS_StartQuery? for question %##s)", question->Target.type, mDNSVal16(question->TargetPort), question->qname.c); question->Target.type = mDNSAddrType_None; } // If no question->Target specified, clear TargetPort if (!question->Target.type) question->TargetPort = zeroIPPort; if (!ValidateDomainName(&question->qname)) { LogMsg("ValidateParameters: Attempt to start query with invalid qname %##s (%s)", question->qname.c, DNSTypeName(question->qtype)); return(mStatus_Invalid); } // If this question is referencing a specific interface, verify it exists if (question->InterfaceID && !LocalOnlyOrP2PInterface(question->InterfaceID) && question->InterfaceID != mDNSInterface_Unicast) { NetworkInterfaceInfo *intf = FirstInterfaceForID(m, question->InterfaceID); if (!intf) LogInfo("ValidateParameters: Note: InterfaceID %d for question %##s (%s) not currently found in active interface list", IID(question->InterfaceID), question->qname.c, DNSTypeName(question->qtype)); } return(mStatus_NoError); } // InitDNSConfig() is called by InitCommonState() to initialize the DNS configuration of the Question. // These are a subset of the internal uDNS fields. Must be done before ShouldSuppressQuery() & mDNS_PurgeForQuestion() mDNSlocal void InitDNSConfig(mDNS *const m, DNSQuestion *const question) { // First reset all DNS Configuration question->qDNSServer = mDNSNULL; question->validDNSServers = zeroOpaque128; question->triedAllServersOnce = 0; question->noServerResponse = 0; question->StopTime = (question->TimeoutQuestion) ? question->StopTime : 0; #if AWD_METRICS mDNSPlatformMemZero(&question->metrics, sizeof(question->metrics)); #endif // Need not initialize the DNS Configuration for Local Only OR P2P Questions when timeout not specified if (LocalOnlyOrP2PInterface(question->InterfaceID) && !question->TimeoutQuestion) return; // Proceed to initialize DNS Configuration (some are set in SetValidDNSServers()) if (!mDNSOpaque16IsZero(question->TargetQID)) { mDNSu32 timeout = SetValidDNSServers(m, question); // We set the timeout value the first time mDNS_StartQuery_internal is called for a question. // So if a question is restarted when a network change occurs, the StopTime is not reset. // Note that we set the timeout for all questions. If this turns out to be a duplicate, // it gets a full timeout value even if the original question times out earlier. if (question->TimeoutQuestion && !question->StopTime) { question->StopTime = NonZeroTime(m->timenow + timeout * mDNSPlatformOneSecond); LogInfo("InitDNSConfig: Setting StopTime on the uDNS question %p %##s (%s)", question, question->qname.c, DNSTypeName(question->qtype)); } question->qDNSServer = GetServerForQuestion(m, question); LogInfo("InitDNSConfig: question %p %##s (%s) Timeout %d, DNS Server %#a:%d", question, question->qname.c, DNSTypeName(question->qtype), timeout, question->qDNSServer ? &question->qDNSServer->addr : mDNSNULL, mDNSVal16(question->qDNSServer ? question->qDNSServer->port : zeroIPPort)); } else if (question->TimeoutQuestion && !question->StopTime) { // If the question is to be timed out and its a multicast, local-only or P2P case, // then set it's stop time. mDNSu32 timeout = LocalOnlyOrP2PInterface(question->InterfaceID) ? DEFAULT_LO_OR_P2P_TIMEOUT : GetTimeoutForMcastQuestion(m, question); question->StopTime = NonZeroTime(m->timenow + timeout * mDNSPlatformOneSecond); LogInfo("InitDNSConfig: Setting StopTime on question %p %##s (%s)", question, question->qname.c, DNSTypeName(question->qtype)); } // Set StopTime here since it is a part of DNS Configuration if (question->StopTime) SetNextQueryStopTime(m, question); // Don't call SetNextQueryTime() if a LocalOnly OR P2P Question since those questions // will never be transmitted on the wire. if (!(LocalOnlyOrP2PInterface(question->InterfaceID))) SetNextQueryTime(m,question); } // InitCommonState() is called by mDNS_StartQuery_internal() to initialize the common(uDNS/mDNS) internal // state fields of the DNS Question. These are independent of the Client layer. mDNSlocal mDNSBool InitCommonState(mDNS *const m, DNSQuestion *const question) { mDNSBool purge; int i; mDNSBool isBlocked = mDNSfalse; // Note: In the case where we already have the answer to this question in our cache, that may be all the client // wanted, and they may immediately cancel their question. In this case, sending an actual query on the wire would // be a waste. For that reason, we schedule our first query to go out in half a second (InitialQuestionInterval). // If AnswerNewQuestion() finds that we have *no* relevant answers currently in our cache, then it will accelerate // that to go out immediately. question->next = mDNSNULL; // ThisQInterval should be initialized before any memory allocations occur. If malloc // debugging is turned on within mDNSResponder (see mDNSDebug.h for details) it validates // the question list to check if ThisQInterval is negative which means the question has been // stopped and can't be on the list. The question is already on the list and ThisQInterval // can be negative if the caller just stopped it and starting it again. Hence, it always has to // be initialized. CheckForSoonToExpireRecords below prints the cache records when logging is // turned ON which can allocate memory e.g., base64 encoding, in the case of DNSSEC. question->ThisQInterval = InitialQuestionInterval; // MUST be > zero for an active question question->qnamehash = DomainNameHashValue(&question->qname); question->DelayAnswering = CheckForSoonToExpireRecords(m, &question->qname, question->qnamehash, &purge); question->LastQTime = m->timenow; question->ExpectUnicastResp = 0; question->LastAnswerPktNum = m->PktNum; question->RecentAnswerPkts = 0; question->CurrentAnswers = 0; #if APPLE_OSX_mDNSResponder // Initial browse threshold used by Finder. #define mDNSFinderBrowseThreshold 20 // Set the threshold at which we move to a passive browse state, // not actively sending queries. if (question->flags & kDNSServiceFlagsThresholdOne) question->BrowseThreshold = 1; else if (question->flags & kDNSServiceFlagsThresholdFinder) question->BrowseThreshold = mDNSFinderBrowseThreshold; else question->BrowseThreshold = 0; #else // APPLE_OSX_mDNSResponder question->BrowseThreshold = 0; #endif // APPLE_OSX_mDNSResponder question->CachedAnswerNeedsUpdate = mDNSfalse; question->LargeAnswers = 0; question->UniqueAnswers = 0; question->LOAddressAnswers = 0; question->FlappingInterface1 = mDNSNULL; question->FlappingInterface2 = mDNSNULL; // if kDNSServiceFlagsServiceIndex flag is SET by the client, then do NOT call mDNSPlatformGetDNSRoutePolicy() // since we would already have the question->ServiceID in that case. if (!(question->flags & kDNSServiceFlagsServiceIndex)) { #if APPLE_OSX_mDNSResponder mDNSPlatformGetDNSRoutePolicy(question, &isBlocked); #else question->ServiceID = -1; #endif } else LogInfo("InitCommonState: Query for %##s (%s), PID[%d], EUID[%d], ServiceID[%d] is already set by client", question->qname.c, DNSTypeName(question->qtype), question->pid, question->euid, question->ServiceID); InitDNSConfig(m, question); question->AuthInfo = GetAuthInfoForQuestion(m, question); question->SuppressQuery = 0; if (question->SuppressUnusable) question->SuppressQuery = ShouldSuppressQuery(m, question); // If ServiceID is 0 or the policy disallows making DNS requests, // set DisallowPID question->DisallowPID = (question->ServiceID == 0 || isBlocked); if (question->DisallowPID) LogInfo("InitCommonState: Query suppressed for %##s (%s), PID %d/ServiceID %d not allowed", question->qname.c, DNSTypeName(question->qtype), question->pid, question->ServiceID); question->NextInDQList = mDNSNULL; question->SendQNow = mDNSNULL; question->SendOnAll = mDNSfalse; question->RequestUnicast = kDefaultRequestUnicastCount; #if APPLE_OSX_mDNSResponder // Set the QU bit in the first query for the following options. if ((question->flags & kDNSServiceFlagsUnicastResponse) || (question->flags & kDNSServiceFlagsThresholdFinder)) { question->RequestUnicast = SET_QU_IN_FIRST_QUERY; LogInfo("InitCommonState: setting RequestUnicast = %d for %##s (%s)", question->RequestUnicast, question->qname.c, DNSTypeName(question->qtype)); } #endif // APPLE_OSX_mDNSResponder question->LastQTxTime = m->timenow; question->CNAMEReferrals = 0; question->WakeOnResolveCount = 0; if (question->WakeOnResolve) { question->WakeOnResolveCount = InitialWakeOnResolveCount; purge = mDNStrue; } for (i=0; iDupSuppress[i].InterfaceID = mDNSNULL; question->Restart = 0; debugf("InitCommonState: Question %##s (%s) Interface %p Now %d Send in %d Answer in %d (%p) %s (%p)", question->qname.c, DNSTypeName(question->qtype), question->InterfaceID, m->timenow, NextQSendTime(question) - m->timenow, question->DelayAnswering ? question->DelayAnswering - m->timenow : 0, question, question->DuplicateOf ? "duplicate of" : "not duplicate", question->DuplicateOf); if (question->DelayAnswering) LogInfo("InitCommonState: Delaying answering for %d ticks while cache stabilizes for %##s (%s)", question->DelayAnswering - m->timenow, question->qname.c, DNSTypeName(question->qtype)); return(purge); } // Excludes the DNS Config fields which are already handled by InitDNSConfig() mDNSlocal void InitWABState(DNSQuestion *const question) { // We'll create our question->LocalSocket on demand, if needed. // We won't need one for duplicate questions, or from questions answered immediately out of the cache. // We also don't need one for LLQs because (when we're using NAT) we want them all to share a single // NAT mapping for receiving inbound add/remove events. question->LocalSocket = mDNSNULL; question->unansweredQueries = 0; question->nta = mDNSNULL; question->servAddr = zeroAddr; question->servPort = zeroIPPort; question->tcp = mDNSNULL; question->NoAnswer = NoAnswer_Normal; } mDNSlocal void InitLLQNATState(mDNS *const m) { // If we don't have our NAT mapping active, start it now if (!m->LLQNAT.clientCallback) { m->LLQNAT.Protocol = NATOp_MapUDP; m->LLQNAT.IntPort = m->UnicastPort4; m->LLQNAT.RequestedPort = m->UnicastPort4; m->LLQNAT.clientCallback = LLQNATCallback; m->LLQNAT.clientContext = (void*)1; // Means LLQ NAT Traversal just started mDNS_StartNATOperation_internal(m, &m->LLQNAT); } } mDNSlocal void InitLLQState(DNSQuestion *const question) { question->state = LLQ_InitialRequest; question->ReqLease = 0; question->expire = 0; question->ntries = 0; question->id = zeroOpaque64; } #ifdef DNS_PUSH_ENABLED mDNSlocal void InitDNSPNState(DNSQuestion *const question) { question->dnsPushState = DNSPUSH_INIT; } #endif // DNS_PUSH_ENABLED // InitDNSSECProxyState() is called by mDNS_StartQuery_internal() to initialize // DNSSEC & DNS Proxy fields of the DNS Question. mDNSlocal void InitDNSSECProxyState(mDNS *const m, DNSQuestion *const question) { (void) m; // DNS server selection affects DNSSEC. Turn off validation if req_DO is not set // or the request is going over cellular interface. // // Note: This needs to be done here before we call FindDuplicateQuestion as it looks // at ValidationRequired setting also. if (question->qDNSServer) { if (question->qDNSServer->cellIntf) { debugf("InitDNSSECProxyState: Turning off validation for %##s (%s); going over cell", question->qname.c, DNSTypeName(question->qtype)); question->ValidationRequired = mDNSfalse; } if (DNSSECOptionalQuestion(question) && !(question->qDNSServer->req_DO)) { LogInfo("InitDNSSECProxyState: Turning off validation for %##s (%s); req_DO false", question->qname.c, DNSTypeName(question->qtype)); question->ValidationRequired = DNSSEC_VALIDATION_NONE; } } question->ValidationState = (question->ValidationRequired ? DNSSECValRequired : DNSSECValNotRequired); question->ValidationStatus = 0; question->responseFlags = zeroID; } // Once the question is completely initialized including the duplicate logic, this function // is called to finalize the unicast question which requires flushing the cache if needed, // activating the query etc. mDNSlocal void FinalizeUnicastQuestion(mDNS *const m, DNSQuestion *question, mDNSBool purge) { // Ensure DNS related info of duplicate question is same as the orig question if (question->DuplicateOf) { question->validDNSServers = question->DuplicateOf->validDNSServers; // If current(dup) question has DNS Server assigned but the original question has no DNS Server assigned to it, // then we log a line as it could indicate an issue if (question->DuplicateOf->qDNSServer == mDNSNULL) { if (question->qDNSServer) LogInfo("FinalizeUnicastQuestion: Current(dup) question %p has DNSServer(%#a:%d) but original question(%p) has no DNS Server! %##s (%s)", question, question->qDNSServer ? &question->qDNSServer->addr : mDNSNULL, mDNSVal16(question->qDNSServer ? question->qDNSServer->port : zeroIPPort), question->DuplicateOf, question->qname.c, DNSTypeName(question->qtype)); } question->qDNSServer = question->DuplicateOf->qDNSServer; LogInfo("FinalizeUnicastQuestion: Duplicate question %p (%p) %##s (%s), DNS Server %#a:%d", question, question->DuplicateOf, question->qname.c, DNSTypeName(question->qtype), question->qDNSServer ? &question->qDNSServer->addr : mDNSNULL, mDNSVal16(question->qDNSServer ? question->qDNSServer->port : zeroIPPort)); } ActivateUnicastQuery(m, question, mDNSfalse); // If purge was set above, flush the cache. Need to do this after we set the // DNS server on the question if (purge) { question->DelayAnswering = 0; mDNS_PurgeForQuestion(m, question); } else if (!question->DuplicateOf && DNSSECQuestion(question)) { // For DNSSEC questions, we need to have the RRSIGs also for verification. CheckForDNSSECRecords(m, question); } if (question->LongLived) { // Unlike other initializations, InitLLQNATState should be done after // we determine that it is a unicast question. LongLived is set for // both multicast and unicast browse questions but we should initialize // the LLQ NAT state only for unicast. Otherwise we will unnecessarily // start the NAT traversal that is not needed. InitLLQNATState(m); #if APPLE_OSX_mDNSResponder UpdateAutoTunnelDomainStatuses(m); #endif } } mDNSexport mStatus mDNS_StartQuery_internal(mDNS *const m, DNSQuestion *const question) { DNSQuestion **q; mStatus vStatus; mDNSBool purge; // First check for cache space (can't do queries if there is no cache space allocated) if (m->rrcache_size == 0) return(mStatus_NoCache); vStatus = ValidateParameters(m, question); if (vStatus) return(vStatus); #ifdef USE_LIBIDN // If the TLD includes high-ascii bytes, assume it will need to be converted to Punycode. // (In the future the root name servers may answer UTF-8 queries directly, but for now they do not.) if (IsHighASCIILabel(LastLabel(&question->qname))) { domainname newname; if (PerformNextPunycodeConversion(question, &newname)) AssignDomainName(&question->qname, &newname); } #endif // USE_LIBIDN question->TargetQID = #ifndef UNICAST_DISABLED (question->Target.type || Question_uDNS(question)) ? mDNS_NewMessageID(m) : #endif // UNICAST_DISABLED zeroID; debugf("mDNS_StartQuery_internal: %##s (%s)", question->qname.c, DNSTypeName(question->qtype)); // Note: It important that new questions are appended at the *end* of the list, not prepended at the start q = &m->Questions; if (LocalOnlyOrP2PInterface(question->InterfaceID)) q = &m->LocalOnlyQuestions; while (*q && *q != question) q=&(*q)->next; if (*q) { LogMsg("mDNS_StartQuery_internal: Error! Tried to add a question %##s (%s) %p that's already in the active list", question->qname.c, DNSTypeName(question->qtype), question); return(mStatus_AlreadyRegistered); } *q = question; // Intialize the question. The only ordering constraint we have today is that // InitDNSSECProxyState should be called after the DNS server is selected (in // InitCommonState -> InitDNSConfig) as DNS server selection affects DNSSEC // validation. purge = InitCommonState(m, question); InitWABState(question); InitLLQState(question); #ifdef DNS_PUSH_ENABLED InitDNSPNState(question); #endif // DNS_PUSH_ENABLED InitDNSSECProxyState(m, question); // FindDuplicateQuestion should be called last after all the intialization // as the duplicate logic could be potentially based on any field in the // question. question->DuplicateOf = FindDuplicateQuestion(m, question); if (question->DuplicateOf) question->AuthInfo = question->DuplicateOf->AuthInfo; if (LocalOnlyOrP2PInterface(question->InterfaceID)) { if (!m->NewLocalOnlyQuestions) m->NewLocalOnlyQuestions = question; } else { if (!m->NewQuestions) m->NewQuestions = question; // If the question's id is non-zero, then it's Wide Area // MUST NOT do this Wide Area setup until near the end of // mDNS_StartQuery_internal -- this code may itself issue queries (e.g. SOA, // NS, etc.) and if we haven't finished setting up our own question and setting // m->NewQuestions if necessary then we could end up recursively re-entering // this routine with the question list data structures in an inconsistent state. if (!mDNSOpaque16IsZero(question->TargetQID)) { FinalizeUnicastQuestion(m, question, purge); } else { #if BONJOUR_ON_DEMAND m->NumAllInterfaceQuestions++; LogInfo("mDNS_StartQuery_internal: NumAllInterfaceRecords %d NumAllInterfaceQuestions %d %##s (%s)", m->NumAllInterfaceRecords, m->NumAllInterfaceQuestions, question->qname.c, DNSTypeName(question->qtype)); if (m->NumAllInterfaceRecords + m->NumAllInterfaceQuestions == 1) { m->NextBonjourDisableTime = 0; if (m->BonjourEnabled == 0) { // Enable Bonjour immediately by scheduling network changed processing where // we will join the multicast group on each active interface. m->BonjourEnabled = 1; m->NetworkChanged = m->timenow; } } #endif // BONJOUR_ON_DEMAND if (purge) { LogInfo("mDNS_StartQuery_internal: Purging for %##s", question->qname.c); mDNS_PurgeForQuestion(m, question); } } } return(mStatus_NoError); } // CancelGetZoneData is an internal routine (i.e. must be called with the lock already held) mDNSexport void CancelGetZoneData(mDNS *const m, ZoneData *nta) { debugf("CancelGetZoneData %##s (%s)", nta->question.qname.c, DNSTypeName(nta->question.qtype)); // This function may be called anytime to free the zone information.The question may or may not have stopped. // If it was already stopped, mDNS_StopQuery_internal would have set q->ThisQInterval to -1 and should not // call it again if (nta->question.ThisQInterval != -1) { mDNS_StopQuery_internal(m, &nta->question); if (nta->question.ThisQInterval != -1) LogMsg("CancelGetZoneData: Question %##s (%s) ThisQInterval %d not -1", nta->question.qname.c, DNSTypeName(nta->question.qtype), nta->question.ThisQInterval); } mDNSPlatformMemFree(nta); } mDNSexport mStatus mDNS_StopQuery_internal(mDNS *const m, DNSQuestion *const question) { CacheGroup *cg = CacheGroupForName(m, question->qnamehash, &question->qname); CacheRecord *rr; DNSQuestion **qp = &m->Questions; //LogInfo("mDNS_StopQuery_internal %##s (%s)", question->qname.c, DNSTypeName(question->qtype)); if (LocalOnlyOrP2PInterface(question->InterfaceID)) qp = &m->LocalOnlyQuestions; while (*qp && *qp != question) qp=&(*qp)->next; if (*qp) *qp = (*qp)->next; else { #if !ForceAlerts if (question->ThisQInterval >= 0) // Only log error message if the query was supposed to be active #endif LogFatalError("mDNS_StopQuery_internal: Question %##s (%s) not found in active list", question->qname.c, DNSTypeName(question->qtype)); return(mStatus_BadReferenceErr); } #if BONJOUR_ON_DEMAND if (!LocalOnlyOrP2PInterface(question->InterfaceID) && mDNSOpaque16IsZero(question->TargetQID)) { if (m->NumAllInterfaceRecords + m->NumAllInterfaceQuestions == 1) m->NextBonjourDisableTime = NonZeroTime(m->timenow + (BONJOUR_DISABLE_DELAY * mDNSPlatformOneSecond)); m->NumAllInterfaceQuestions--; LogInfo("mDNS_StopQuery_internal: NumAllInterfaceRecords %d NumAllInterfaceQuestions %d %##s (%s)", m->NumAllInterfaceRecords, m->NumAllInterfaceQuestions, question->qname.c, DNSTypeName(question->qtype)); } #endif // BONJOUR_ON_DEMAND #if AWD_METRICS if (Question_uDNS(question) && !question->metrics.answered && (question->metrics.querySendCount > 0)) { const domainname * queryName; mDNSBool isForCell; mDNSu32 durationMs; queryName = question->metrics.originalQName ? question->metrics.originalQName : &question->qname; isForCell = (question->qDNSServer && question->qDNSServer->cellIntf); durationMs = ((m->timenow - question->metrics.firstQueryTime) * 1000) / mDNSPlatformOneSecond; MetricsUpdateDNSQueryStats(queryName, question->qtype, mDNSNULL, question->metrics.querySendCount, durationMs, isForCell); } #endif // Take care to cut question from list *before* calling UpdateQuestionDuplicates UpdateQuestionDuplicates(m, question); // But don't trash ThisQInterval until afterwards. question->ThisQInterval = -1; // If there are any cache records referencing this as their active question, then see if there is any // other question that is also referencing them, else their CRActiveQuestion needs to get set to NULL. for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) { if (rr->CRActiveQuestion == question) { DNSQuestion *q; DNSQuestion *replacement = mDNSNULL; // If we find an active question that is answered by this cached record, use it as the cache record's // CRActiveQuestion replacement. If there are no such questions, but there's at least one unsuppressed inactive // question that is answered by this cache record, then use an inactive one to not forgo generating RMV events // via CacheRecordRmv() when the cache record expires. for (q = m->Questions; q && (q != m->NewQuestions); q = q->next) { if (!q->DuplicateOf && !QuerySuppressed(q) && ResourceRecordAnswersQuestion(&rr->resrec, q)) { if (q->ThisQInterval > 0) { replacement = q; break; } else if (!replacement) { replacement = q; } } } if (replacement) debugf("mDNS_StopQuery_internal: Updating CRActiveQuestion to %p for cache record %s, Original question CurrentAnswers %d, new question " "CurrentAnswers %d, SuppressQuery %d", replacement, CRDisplayString(m,rr), question->CurrentAnswers, replacement->CurrentAnswers, replacement->SuppressQuery); rr->CRActiveQuestion = replacement; // Question used to be active; new value may or may not be null if (!replacement) m->rrcache_active--; // If no longer active, decrement rrcache_active count } } // If we just deleted the question that CacheRecordAdd() or CacheRecordRmv() is about to look at, // bump its pointer forward one question. if (m->CurrentQuestion == question) { debugf("mDNS_StopQuery_internal: Just deleted the currently active question: %##s (%s)", question->qname.c, DNSTypeName(question->qtype)); m->CurrentQuestion = question->next; } if (m->NewQuestions == question) { debugf("mDNS_StopQuery_internal: Just deleted a new question that wasn't even answered yet: %##s (%s)", question->qname.c, DNSTypeName(question->qtype)); m->NewQuestions = question->next; } if (m->NewLocalOnlyQuestions == question) m->NewLocalOnlyQuestions = question->next; if (m->RestartQuestion == question) { LogMsg("mDNS_StopQuery_internal: Just deleted the current restart question: %##s (%s)", question->qname.c, DNSTypeName(question->qtype)); m->RestartQuestion = question->next; } if (m->ValidationQuestion == question) { LogInfo("mDNS_StopQuery_internal: Just deleted the current Validation question: %##s (%s)", question->qname.c, DNSTypeName(question->qtype)); m->ValidationQuestion = question->next; } // Take care not to trash question->next until *after* we've updated m->CurrentQuestion and m->NewQuestions question->next = mDNSNULL; // LogMsg("mDNS_StopQuery_internal: Question %##s (%s) removed", question->qname.c, DNSTypeName(question->qtype)); // And finally, cancel any associated GetZoneData operation that's still running. // Must not do this until last, because there's a good chance the GetZoneData question is the next in the list, // so if we delete it earlier in this routine, we could find that our "question->next" pointer above is already // invalid before we even use it. By making sure that we update m->CurrentQuestion and m->NewQuestions if necessary // *first*, then they're all ready to be updated a second time if necessary when we cancel our GetZoneData query. if (question->tcp) { DisposeTCPConn(question->tcp); question->tcp = mDNSNULL; } if (question->LocalSocket) { mDNSPlatformUDPClose(question->LocalSocket); question->LocalSocket = mDNSNULL; } if (!mDNSOpaque16IsZero(question->TargetQID) && question->LongLived) { // Scan our list to see if any more wide-area LLQs remain. If not, stop our NAT Traversal. DNSQuestion *q; for (q = m->Questions; q; q=q->next) if (!mDNSOpaque16IsZero(q->TargetQID) && q->LongLived) break; if (!q) { if (!m->LLQNAT.clientCallback) // Should never happen, but just in case... { LogMsg("mDNS_StopQuery ERROR LLQNAT.clientCallback NULL"); } else { LogInfo("Stopping LLQNAT"); mDNS_StopNATOperation_internal(m, &m->LLQNAT); m->LLQNAT.clientCallback = mDNSNULL; // Means LLQ NAT Traversal not running } } // If necessary, tell server it can delete this LLQ state if (question->state == LLQ_Established) { question->ReqLease = 0; sendLLQRefresh(m, question); // If we need need to make a TCP connection to cancel the LLQ, that's going to take a little while. // We clear the tcp->question backpointer so that when the TCP connection completes, it doesn't // crash trying to access our cancelled question, but we don't cancel the TCP operation itself -- // we let that run out its natural course and complete asynchronously. if (question->tcp) { question->tcp->question = mDNSNULL; question->tcp = mDNSNULL; } } #ifdef DNS_PUSH_ENABLED else if (question->dnsPushState == DNSPUSH_ESTABLISHED) { if (question->tcp) { UnSubscribeToDNSPushNotificationServer(m, q); question->tcp->question = mDNSNULL; question->tcp = mDNSNULL; } } #endif // DNS_PUSH_ENABLED #if APPLE_OSX_mDNSResponder UpdateAutoTunnelDomainStatuses(m); #endif } // wait until we send the refresh above which needs the nta if (question->nta) { CancelGetZoneData(m, question->nta); question->nta = mDNSNULL; } if (question->ValidationRequired && question->DNSSECAuthInfo) { LogInfo("mDNS_StopQuery_internal: freeing DNSSECAuthInfo %##s", question->qname.c); question->DAIFreeCallback(m, question->DNSSECAuthInfo); question->DNSSECAuthInfo = mDNSNULL; } if (question->AnonInfo) { FreeAnonInfo(question->AnonInfo); question->AnonInfo = mDNSNULL; } #if AWD_METRICS if (question->metrics.originalQName) { mDNSPlatformMemFree(question->metrics.originalQName); question->metrics.originalQName = mDNSNULL; } #endif #if USE_DNS64 DNS64ResetState(question); #endif return(mStatus_NoError); } mDNSexport mStatus mDNS_StartQuery(mDNS *const m, DNSQuestion *const question) { mStatus status; mDNS_Lock(m); status = mDNS_StartQuery_internal(m, question); mDNS_Unlock(m); return(status); } mDNSexport mStatus mDNS_StopQuery(mDNS *const m, DNSQuestion *const question) { mStatus status; mDNS_Lock(m); status = mDNS_StopQuery_internal(m, question); mDNS_Unlock(m); return(status); } // Note that mDNS_StopQueryWithRemoves() does not currently implement the full generality of the other APIs // Specifically, question callbacks invoked as a result of this call cannot themselves make API calls. // We invoke the callback without using mDNS_DropLockBeforeCallback/mDNS_ReclaimLockAfterCallback // specifically to catch and report if the client callback does try to make API calls mDNSexport mStatus mDNS_StopQueryWithRemoves(mDNS *const m, DNSQuestion *const question) { mStatus status; DNSQuestion *qq; mDNS_Lock(m); // Check if question is new -- don't want to give remove events for a question we haven't even answered yet for (qq = m->NewQuestions; qq; qq=qq->next) if (qq == question) break; status = mDNS_StopQuery_internal(m, question); if (status == mStatus_NoError && !qq) { const CacheRecord *rr; CacheGroup *const cg = CacheGroupForName(m, question->qnamehash, &question->qname); LogInfo("Generating terminal removes for %##s (%s)", question->qname.c, DNSTypeName(question->qtype)); for (rr = cg ? cg->members : mDNSNULL; rr; rr=rr->next) if (rr->resrec.RecordType != kDNSRecordTypePacketNegative && SameNameRecordAnswersQuestion(&rr->resrec, question)) { // Don't use mDNS_DropLockBeforeCallback() here, since we don't allow API calls if (question->QuestionCallback) question->QuestionCallback(m, question, &rr->resrec, mDNSfalse); } } mDNS_Unlock(m); return(status); } mDNSexport mStatus mDNS_Reconfirm(mDNS *const m, CacheRecord *const cr) { mStatus status; mDNS_Lock(m); status = mDNS_Reconfirm_internal(m, cr, kDefaultReconfirmTimeForNoAnswer); if (status == mStatus_NoError) ReconfirmAntecedents(m, cr->resrec.name, cr->resrec.namehash, 0); mDNS_Unlock(m); return(status); } mDNSexport mStatus mDNS_ReconfirmByValue(mDNS *const m, ResourceRecord *const rr) { mStatus status = mStatus_BadReferenceErr; CacheRecord *cr; mDNS_Lock(m); cr = FindIdenticalRecordInCache(m, rr); debugf("mDNS_ReconfirmByValue: %p %s", cr, RRDisplayString(m, rr)); if (cr) status = mDNS_Reconfirm_internal(m, cr, kDefaultReconfirmTimeForNoAnswer); if (status == mStatus_NoError) ReconfirmAntecedents(m, cr->resrec.name, cr->resrec.namehash, 0); mDNS_Unlock(m); return(status); } mDNSlocal mStatus mDNS_StartBrowse_internal(mDNS *const m, DNSQuestion *const question, const domainname *const srv, const domainname *const domain, const mDNSu8 *anondata, const mDNSInterfaceID InterfaceID, mDNSu32 flags, mDNSBool ForceMCast, mDNSBool useBackgroundTrafficClass, mDNSQuestionCallback *Callback, void *Context) { question->InterfaceID = InterfaceID; question->flags = flags; question->Target = zeroAddr; question->qtype = kDNSType_PTR; question->qclass = kDNSClass_IN; question->LongLived = mDNStrue; question->ExpectUnique = mDNSfalse; question->ForceMCast = ForceMCast; question->ReturnIntermed = (flags & kDNSServiceFlagsReturnIntermediates) != 0; question->SuppressUnusable = mDNSfalse; question->SearchListIndex = 0; question->AppendSearchDomains = 0; question->RetryWithSearchDomains = mDNSfalse; question->TimeoutQuestion = 0; question->WakeOnResolve = 0; question->UseBackgroundTrafficClass = useBackgroundTrafficClass; question->ValidationRequired = 0; question->ValidatingResponse = 0; question->ProxyQuestion = 0; question->qnameOrig = mDNSNULL; question->AnonInfo = mDNSNULL; question->QuestionCallback = Callback; question->QuestionContext = Context; if (!ConstructServiceName(&question->qname, mDNSNULL, srv, domain)) return(mStatus_BadParamErr); if (anondata) { question->AnonInfo = AllocateAnonInfo(&question->qname, anondata, mDNSPlatformStrLen(anondata), mDNSNULL); if (!question->AnonInfo) return(mStatus_BadParamErr); } return(mDNS_StartQuery_internal(m, question)); } mDNSexport mStatus mDNS_StartBrowse(mDNS *const m, DNSQuestion *const question, const domainname *const srv, const domainname *const domain, const mDNSu8 *anondata, const mDNSInterfaceID InterfaceID, mDNSu32 flags, mDNSBool ForceMCast, mDNSBool useBackgroundTrafficClass, mDNSQuestionCallback *Callback, void *Context) { mStatus status; mDNS_Lock(m); status = mDNS_StartBrowse_internal(m, question, srv, domain, anondata, InterfaceID, flags, ForceMCast, useBackgroundTrafficClass, Callback, Context); mDNS_Unlock(m); return(status); } mDNSexport mStatus mDNS_GetDomains(mDNS *const m, DNSQuestion *const question, mDNS_DomainType DomainType, const domainname *dom, const mDNSInterfaceID InterfaceID, mDNSQuestionCallback *Callback, void *Context) { question->InterfaceID = InterfaceID; question->flags = 0; question->Target = zeroAddr; question->qtype = kDNSType_PTR; question->qclass = kDNSClass_IN; question->LongLived = mDNSfalse; question->ExpectUnique = mDNSfalse; question->ForceMCast = mDNSfalse; question->ReturnIntermed = mDNSfalse; question->SuppressUnusable = mDNSfalse; question->SearchListIndex = 0; question->AppendSearchDomains = 0; question->RetryWithSearchDomains = mDNSfalse; question->TimeoutQuestion = 0; question->WakeOnResolve = 0; question->UseBackgroundTrafficClass = mDNSfalse; question->ValidationRequired = 0; question->ValidatingResponse = 0; question->ProxyQuestion = 0; question->qnameOrig = mDNSNULL; question->AnonInfo = mDNSNULL; question->pid = mDNSPlatformGetPID(); question->euid = 0; question->QuestionCallback = Callback; question->QuestionContext = Context; if (DomainType > mDNS_DomainTypeMax) return(mStatus_BadParamErr); if (!MakeDomainNameFromDNSNameString(&question->qname, mDNS_DomainTypeNames[DomainType])) return(mStatus_BadParamErr); if (!dom) dom = &localdomain; if (!AppendDomainName(&question->qname, dom)) return(mStatus_BadParamErr); return(mDNS_StartQuery(m, question)); } // *************************************************************************** #if COMPILER_LIKES_PRAGMA_MARK #pragma mark - #pragma mark - Responder Functions #endif mDNSexport mStatus mDNS_Register(mDNS *const m, AuthRecord *const rr) { mStatus status; mDNS_Lock(m); status = mDNS_Register_internal(m, rr); mDNS_Unlock(m); return(status); } mDNSexport mStatus mDNS_Update(mDNS *const m, AuthRecord *const rr, mDNSu32 newttl, const mDNSu16 newrdlength, RData *const newrdata, mDNSRecordUpdateCallback *Callback) { if (!ValidateRData(rr->resrec.rrtype, newrdlength, newrdata)) { LogMsg("Attempt to update record with invalid rdata: %s", GetRRDisplayString_rdb(&rr->resrec, &newrdata->u, m->MsgBuffer)); return(mStatus_Invalid); } mDNS_Lock(m); // If TTL is unspecified, leave TTL unchanged if (newttl == 0) newttl = rr->resrec.rroriginalttl; // If we already have an update queued up which has not gone through yet, give the client a chance to free that memory if (rr->NewRData) { RData *n = rr->NewRData; rr->NewRData = mDNSNULL; // Clear the NewRData pointer ... if (rr->UpdateCallback) rr->UpdateCallback(m, rr, n, rr->newrdlength); // ...and let the client free this memory, if necessary } rr->NewRData = newrdata; rr->newrdlength = newrdlength; rr->UpdateCallback = Callback; #ifndef UNICAST_DISABLED if (rr->ARType != AuthRecordLocalOnly && rr->ARType != AuthRecordP2P && !IsLocalDomain(rr->resrec.name)) { mStatus status = uDNS_UpdateRecord(m, rr); // The caller frees the memory on error, don't retain stale pointers if (status != mStatus_NoError) { rr->NewRData = mDNSNULL; rr->newrdlength = 0; } mDNS_Unlock(m); return(status); } #endif if (RRLocalOnly(rr) || (rr->resrec.rroriginalttl == newttl && rr->resrec.rdlength == newrdlength && mDNSPlatformMemSame(rr->resrec.rdata->u.data, newrdata->u.data, newrdlength))) CompleteRDataUpdate(m, rr); else { rr->AnnounceCount = InitialAnnounceCount; InitializeLastAPTime(m, rr); while (rr->NextUpdateCredit && m->timenow - rr->NextUpdateCredit >= 0) GrantUpdateCredit(rr); if (!rr->UpdateBlocked && rr->UpdateCredits) rr->UpdateCredits--; if (!rr->NextUpdateCredit) rr->NextUpdateCredit = NonZeroTime(m->timenow + kUpdateCreditRefreshInterval); if (rr->AnnounceCount > rr->UpdateCredits + 1) rr->AnnounceCount = (mDNSu8)(rr->UpdateCredits + 1); if (rr->UpdateCredits <= 5) { mDNSu32 delay = 6 - rr->UpdateCredits; // Delay 1 second, then 2, then 3, etc. up to 6 seconds maximum if (!rr->UpdateBlocked) rr->UpdateBlocked = NonZeroTime(m->timenow + (mDNSs32)delay * mDNSPlatformOneSecond); rr->ThisAPInterval *= 4; rr->LastAPTime = rr->UpdateBlocked - rr->ThisAPInterval; LogMsg("Excessive update rate for %##s; delaying announcement by %ld second%s", rr->resrec.name->c, delay, delay > 1 ? "s" : ""); } rr->resrec.rroriginalttl = newttl; } mDNS_Unlock(m); return(mStatus_NoError); } // Note: mDNS_Deregister calls mDNS_Deregister_internal which can call a user callback, which may change // the record list and/or question list. // Any code walking either list must use the CurrentQuestion and/or CurrentRecord mechanism to protect against this. mDNSexport mStatus mDNS_Deregister(mDNS *const m, AuthRecord *const rr) { mStatus status; mDNS_Lock(m); status = mDNS_Deregister_internal(m, rr, mDNS_Dereg_normal); mDNS_Unlock(m); return(status); } // Circular reference: AdvertiseInterface references mDNS_HostNameCallback, which calls mDNS_SetFQDN, which call AdvertiseInterface mDNSlocal void mDNS_HostNameCallback(mDNS *const m, AuthRecord *const rr, mStatus result); mDNSlocal NetworkInterfaceInfo *FindFirstAdvertisedInterface(mDNS *const m) { NetworkInterfaceInfo *intf; for (intf = m->HostInterfaces; intf; intf = intf->next) if (intf->Advertise) break; return(intf); } // The parameter "set" here refers to the set of AuthRecords used to advertise this interface. // (It's a set of records, not a set of interfaces.) mDNSlocal void AdvertiseInterface(mDNS *const m, NetworkInterfaceInfo *set) { char buffer[MAX_REVERSE_MAPPING_NAME]; NetworkInterfaceInfo *primary; mDNSu8 recordType; if (m->AutoTargetServices == 0) { LogInfo("AdvertiseInterface: Returning due to AutoTargetServices zero for %s", set->ifname); return; } primary = FindFirstAdvertisedInterface(m); if (!primary) primary = set; // If no existing advertised interface, this new NetworkInterfaceInfo becomes our new primary // We should never have primary be NULL, because even if there is // no other interface yet, we should always find ourself in the list. // If interface is marked as a direct link, we can assume the address record is unique // and does not need to go through the probe phase of the probe/announce packet sequence. recordType = (set->DirectLink ? kDNSRecordTypeKnownUnique : kDNSRecordTypeUnique); if (set->DirectLink) LogInfo("AdvertiseInterface: Marking address record as kDNSRecordTypeKnownUnique for %s", set->ifname); // Send dynamic update for non-linklocal IPv4 Addresses mDNS_SetupResourceRecord(&set->RR_A, mDNSNULL, set->InterfaceID, kDNSType_A, kHostNameTTL, recordType, AuthRecordAny, mDNS_HostNameCallback, set); mDNS_SetupResourceRecord(&set->RR_PTR, mDNSNULL, set->InterfaceID, kDNSType_PTR, kHostNameTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); mDNS_SetupResourceRecord(&set->RR_HINFO, mDNSNULL, set->InterfaceID, kDNSType_HINFO, kHostNameTTL, kDNSRecordTypeUnique, AuthRecordAny, mDNSNULL, mDNSNULL); #if ANSWER_REMOTE_HOSTNAME_QUERIES set->RR_A.AllowRemoteQuery = mDNStrue; set->RR_PTR.AllowRemoteQuery = mDNStrue; set->RR_HINFO.AllowRemoteQuery = mDNStrue; #endif // 1. Set up Address record to map from host name ("foo.local.") to IP address // 2. Set up reverse-lookup PTR record to map from our address back to our host name AssignDomainName(&set->RR_A.namestorage, &m->MulticastHostname); if (set->ip.type == mDNSAddrType_IPv4) { set->RR_A.resrec.rrtype = kDNSType_A; set->RR_A.resrec.rdata->u.ipv4 = set->ip.ip.v4; // Note: This is reverse order compared to a normal dotted-decimal IP address, so we can't use our customary "%.4a" format code mDNS_snprintf(buffer, sizeof(buffer), "%d.%d.%d.%d.in-addr.arpa.", set->ip.ip.v4.b[3], set->ip.ip.v4.b[2], set->ip.ip.v4.b[1], set->ip.ip.v4.b[0]); } else if (set->ip.type == mDNSAddrType_IPv6) { int i; set->RR_A.resrec.rrtype = kDNSType_AAAA; set->RR_A.resrec.rdata->u.ipv6 = set->ip.ip.v6; for (i = 0; i < 16; i++) { static const char hexValues[] = "0123456789ABCDEF"; buffer[i * 4 ] = hexValues[set->ip.ip.v6.b[15 - i] & 0x0F]; buffer[i * 4 + 1] = '.'; buffer[i * 4 + 2] = hexValues[set->ip.ip.v6.b[15 - i] >> 4]; buffer[i * 4 + 3] = '.'; } mDNS_snprintf(&buffer[64], sizeof(buffer)-64, "ip6.arpa."); } MakeDomainNameFromDNSNameString(&set->RR_PTR.namestorage, buffer); set->RR_PTR.AutoTarget = Target_AutoHost; // Tell mDNS that the target of this PTR is to be kept in sync with our host name set->RR_PTR.ForceMCast = mDNStrue; // This PTR points to our dot-local name, so don't ever try to write it into a uDNS server set->RR_A.RRSet = &primary->RR_A; // May refer to self mDNS_Register_internal(m, &set->RR_A); mDNS_Register_internal(m, &set->RR_PTR); #if APPLE_OSX_mDNSResponder // must be after the mDNS_Register_internal() calls so that records have complete rdata fields, etc D2D_start_advertising_interface(set); #endif // APPLE_OSX_mDNSResponder if (!NO_HINFO && m->HIHardware.c[0] > 0 && m->HISoftware.c[0] > 0 && m->HIHardware.c[0] + m->HISoftware.c[0] <= 254) { mDNSu8 *p = set->RR_HINFO.resrec.rdata->u.data; AssignDomainName(&set->RR_HINFO.namestorage, &m->MulticastHostname); set->RR_HINFO.DependentOn = &set->RR_A; mDNSPlatformMemCopy(p, &m->HIHardware, 1 + (mDNSu32)m->HIHardware.c[0]); p += 1 + (int)p[0]; mDNSPlatformMemCopy(p, &m->HISoftware, 1 + (mDNSu32)m->HISoftware.c[0]); mDNS_Register_internal(m, &set->RR_HINFO); } else { debugf("Not creating HINFO record: platform support layer provided no information"); set->RR_HINFO.resrec.RecordType = kDNSRecordTypeUnregistered; } } mDNSlocal void DeadvertiseInterface(mDNS *const m, NetworkInterfaceInfo *set) { if (m->AutoTargetServices == 0) { LogInfo("DeadvertiseInterface: Returning due to AutoTargetServices zero for %s", set->ifname); return; } #if APPLE_OSX_mDNSResponder D2D_stop_advertising_interface(set); #endif // APPLE_OSX_mDNSResponder // Unregister these records. // When doing the mDNS_Exit processing, we first call DeadvertiseInterface for each interface, so by the time the platform // support layer gets to call mDNS_DeregisterInterface, the address and PTR records have already been deregistered for it. // Also, in the event of a name conflict, one or more of our records will have been forcibly deregistered. // To avoid unnecessary and misleading warning messages, we check the RecordType before calling mDNS_Deregister_internal(). if (set->RR_A .resrec.RecordType) mDNS_Deregister_internal(m, &set->RR_A, mDNS_Dereg_normal); if (set->RR_PTR .resrec.RecordType) mDNS_Deregister_internal(m, &set->RR_PTR, mDNS_Dereg_normal); if (set->RR_HINFO.resrec.RecordType) mDNS_Deregister_internal(m, &set->RR_HINFO, mDNS_Dereg_normal); } mDNSlocal void AdvertiseAllInterfaceRecords(mDNS *const m) { NetworkInterfaceInfo *intf; for (intf = m->HostInterfaces; intf; intf = intf->next) { if (intf->Advertise) { LogInfo("AdvertiseInterface: Advertising for ifname %s", intf->ifname); AdvertiseInterface(m, intf); } } } mDNSlocal void DeadvertiseAllInterfaceRecords(mDNS *const m) { NetworkInterfaceInfo *intf; for (intf = m->HostInterfaces; intf; intf = intf->next) { if (intf->Advertise) { LogInfo("DeadvertiseInterface: Deadvertising for ifname %s", intf->ifname); DeadvertiseInterface(m, intf); } } } // Change target host name for record. mDNSlocal void UpdateTargetHostName(mDNS *const m, AuthRecord *const rr) { #if APPLE_OSX_mDNSResponder // If this record was also registered with any D2D plugins, stop advertising // the version with the old host name. D2D_stop_advertising_record(rr); #endif SetTargetToHostName(m, rr); #if APPLE_OSX_mDNSResponder // Advertise the record with the updated host name with the D2D plugins if appropriate. D2D_start_advertising_record(rr); #endif } mDNSexport void mDNS_SetFQDN(mDNS *const m) { domainname newmname; AuthRecord *rr; newmname.c[0] = 0; if (!AppendDomainLabel(&newmname, &m->hostlabel)) { LogMsg("ERROR: mDNS_SetFQDN: Cannot create MulticastHostname"); return; } if (!AppendLiteralLabelString(&newmname, "local")) { LogMsg("ERROR: mDNS_SetFQDN: Cannot create MulticastHostname"); return; } mDNS_Lock(m); if (SameDomainNameCS(&m->MulticastHostname, &newmname)) debugf("mDNS_SetFQDN - hostname unchanged"); else { AssignDomainName(&m->MulticastHostname, &newmname); DeadvertiseAllInterfaceRecords(m); AdvertiseAllInterfaceRecords(m); } // 3. Make sure that any AutoTarget SRV records (and the like) get updated for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->AutoTarget) UpdateTargetHostName(m, rr); for (rr = m->DuplicateRecords; rr; rr=rr->next) if (rr->AutoTarget) UpdateTargetHostName(m, rr); mDNS_Unlock(m); } mDNSlocal void mDNS_HostNameCallback(mDNS *const m, AuthRecord *const rr, mStatus result) { (void)rr; // Unused parameter #if MDNS_DEBUGMSGS { char *msg = "Unknown result"; if (result == mStatus_NoError) msg = "Name registered"; else if (result == mStatus_NameConflict) msg = "Name conflict"; debugf("mDNS_HostNameCallback: %##s (%s) %s (%ld)", rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype), msg, result); } #endif if (result == mStatus_NoError) { // Notify the client that the host name is successfully registered if (m->MainCallback) m->MainCallback(m, mStatus_NoError); } else if (result == mStatus_NameConflict) { domainlabel oldlabel = m->hostlabel; // 1. First give the client callback a chance to pick a new name if (m->MainCallback) m->MainCallback(m, mStatus_NameConflict); // 2. If the client callback didn't do it, add (or increment) an index ourselves // This needs to be case-INSENSITIVE compare, because we need to know that the name has been changed so as to // remedy the conflict, and a name that differs only in capitalization will just suffer the exact same conflict again. if (SameDomainLabel(m->hostlabel.c, oldlabel.c)) IncrementLabelSuffix(&m->hostlabel, mDNSfalse); // 3. Generate the FQDNs from the hostlabel, // and make sure all SRV records, etc., are updated to reference our new hostname mDNS_SetFQDN(m); LogMsg("Local Hostname %#s.local already in use; will try %#s.local instead", oldlabel.c, m->hostlabel.c); } else if (result == mStatus_MemFree) { // .local hostnames do not require goodbyes - we ignore the MemFree (which is sent directly by // mDNS_Deregister_internal), and allow the caller to deallocate immediately following mDNS_DeadvertiseInterface debugf("mDNS_HostNameCallback: MemFree (ignored)"); } else LogMsg("mDNS_HostNameCallback: Unknown error %d for registration of record %s", result, rr->resrec.name->c); } mDNSlocal void UpdateInterfaceProtocols(mDNS *const m, NetworkInterfaceInfo *active) { NetworkInterfaceInfo *intf; active->IPv4Available = mDNSfalse; active->IPv6Available = mDNSfalse; for (intf = m->HostInterfaces; intf; intf = intf->next) if (intf->InterfaceID == active->InterfaceID) { if (intf->ip.type == mDNSAddrType_IPv4 && intf->McastTxRx) active->IPv4Available = mDNStrue; if (intf->ip.type == mDNSAddrType_IPv6 && intf->McastTxRx) active->IPv6Available = mDNStrue; } } mDNSlocal void RestartRecordGetZoneData(mDNS * const m) { AuthRecord *rr; LogInfo("RestartRecordGetZoneData: ResourceRecords"); for (rr = m->ResourceRecords; rr; rr=rr->next) if (AuthRecord_uDNS(rr) && rr->state != regState_NoTarget) { debugf("RestartRecordGetZoneData: StartGetZoneData for %##s", rr->resrec.name->c); // Zero out the updateid so that if we have a pending response from the server, it won't // be accepted as a valid response. If we accept the response, we might free the new "nta" if (rr->nta) { rr->updateid = zeroID; CancelGetZoneData(m, rr->nta); } rr->nta = StartGetZoneData(m, rr->resrec.name, ZoneServiceUpdate, RecordRegistrationGotZoneData, rr); } } mDNSlocal void InitializeNetWakeState(mDNS *const m, NetworkInterfaceInfo *set) { int i; // We initialize ThisQInterval to -1 indicating that the question has not been started // yet. If the question (browse) is started later during interface registration, it will // be stopped during interface deregistration. We can't sanity check to see if the // question has been stopped or not before initializing it to -1 because we need to // initialize it to -1 the very first time. set->NetWakeBrowse.ThisQInterval = -1; for (i=0; i<3; i++) { set->NetWakeResolve[i].ThisQInterval = -1; set->SPSAddr[i].type = mDNSAddrType_None; } set->NextSPSAttempt = -1; set->NextSPSAttemptTime = m->timenow; } mDNSexport void mDNS_ActivateNetWake_internal(mDNS *const m, NetworkInterfaceInfo *set) { NetworkInterfaceInfo *p = m->HostInterfaces; while (p && p != set) p=p->next; if (!p) { LogMsg("mDNS_ActivateNetWake_internal: NetworkInterfaceInfo %p not found in active list", set); return; } if (set->InterfaceActive) { LogSPS("ActivateNetWake for %s (%#a)", set->ifname, &set->ip); mDNS_StartBrowse_internal(m, &set->NetWakeBrowse, &SleepProxyServiceType, &localdomain, mDNSNULL, set->InterfaceID, 0, mDNSfalse, mDNSfalse, m->SPSBrowseCallback, set); } } mDNSexport void mDNS_DeactivateNetWake_internal(mDNS *const m, NetworkInterfaceInfo *set) { NetworkInterfaceInfo *p = m->HostInterfaces; while (p && p != set) p=p->next; if (!p) { LogMsg("mDNS_DeactivateNetWake_internal: NetworkInterfaceInfo %p not found in active list", set); return; } // Note: We start the browse only if the interface is NetWake capable and we use this to // stop the resolves also. Hence, the resolves should not be started without the browse // being started i.e, resolves should not happen unless NetWake capable which is // guaranteed by BeginSleepProcessing. if (set->NetWakeBrowse.ThisQInterval >= 0) { int i; LogSPS("DeactivateNetWake for %s (%#a)", set->ifname, &set->ip); // Stop our browse and resolve operations mDNS_StopQuery_internal(m, &set->NetWakeBrowse); for (i=0; i<3; i++) if (set->NetWakeResolve[i].ThisQInterval >= 0) mDNS_StopQuery_internal(m, &set->NetWakeResolve[i]); // Make special call to the browse callback to let it know it can to remove all records for this interface if (m->SPSBrowseCallback) { mDNS_DropLockBeforeCallback(); // Allow client to legally make mDNS API calls from the callback m->SPSBrowseCallback(m, &set->NetWakeBrowse, mDNSNULL, mDNSfalse); mDNS_ReclaimLockAfterCallback(); // Decrement mDNS_reentrancy to block mDNS API calls again } // Reset our variables back to initial state, so we're ready for when NetWake is turned back on // (includes resetting NetWakeBrowse.ThisQInterval back to -1) InitializeNetWakeState(m, set); } } mDNSexport mStatus mDNS_RegisterInterface(mDNS *const m, NetworkInterfaceInfo *set, InterfaceActivationSpeed activationSpeed) { AuthRecord *rr; mDNSBool FirstOfType = mDNStrue; NetworkInterfaceInfo **p = &m->HostInterfaces; if (!set->InterfaceID) { LogMsg("mDNS_RegisterInterface: Error! Tried to register a NetworkInterfaceInfo %#a with zero InterfaceID", &set->ip); return(mStatus_Invalid); } if (!mDNSAddressIsValidNonZero(&set->mask)) { LogMsg("mDNS_RegisterInterface: Error! Tried to register a NetworkInterfaceInfo %#a with invalid mask %#a", &set->ip, &set->mask); return(mStatus_Invalid); } mDNS_Lock(m); // Assume this interface will be active now, unless we find a duplicate already in the list set->InterfaceActive = mDNStrue; set->IPv4Available = (mDNSu8)(set->ip.type == mDNSAddrType_IPv4 && set->McastTxRx); set->IPv6Available = (mDNSu8)(set->ip.type == mDNSAddrType_IPv6 && set->McastTxRx); InitializeNetWakeState(m, set); // Scan list to see if this InterfaceID is already represented while (*p) { if (*p == set) { LogMsg("mDNS_RegisterInterface: Error! Tried to register a NetworkInterfaceInfo that's already in the list"); mDNS_Unlock(m); return(mStatus_AlreadyRegistered); } if ((*p)->InterfaceID == set->InterfaceID) { // This InterfaceID already represented by a different interface in the list, so mark this instance inactive for now set->InterfaceActive = mDNSfalse; if (set->ip.type == (*p)->ip.type) FirstOfType = mDNSfalse; if (set->ip.type == mDNSAddrType_IPv4 && set->McastTxRx) (*p)->IPv4Available = mDNStrue; if (set->ip.type == mDNSAddrType_IPv6 && set->McastTxRx) (*p)->IPv6Available = mDNStrue; } p=&(*p)->next; } set->next = mDNSNULL; *p = set; if (set->Advertise) AdvertiseInterface(m, set); LogInfo("mDNS_RegisterInterface: InterfaceID %d %s (%#a) %s", IID(set->InterfaceID), set->ifname, &set->ip, set->InterfaceActive ? "not represented in list; marking active and retriggering queries" : "already represented in list; marking inactive for now"); if (set->NetWake) mDNS_ActivateNetWake_internal(m, set); // In early versions of OS X the IPv6 address remains on an interface even when the interface is turned off, // giving the false impression that there's an active representative of this interface when there really isn't. // Therefore, when registering an interface, we want to re-trigger our questions and re-probe our Resource Records, // even if we believe that we previously had an active representative of this interface. if (set->McastTxRx && (FirstOfType || set->InterfaceActive)) { DNSQuestion *q; // Normally, after an interface comes up, we pause half a second before beginning probing. // This is to guard against cases where there's rapid interface changes, where we could be confused by // seeing packets we ourselves sent just moments ago (perhaps when this interface had a different address) // which are then echoed back after a short delay by some Ethernet switches and some 802.11 base stations. // We don't want to do a probe, and then see a stale echo of an announcement we ourselves sent, // and think it's a conflicting answer to our probe. // In the case of a flapping interface, we pause for five seconds, and reduce the announcement count to one packet. mDNSs32 probedelay; mDNSu8 numannounce; switch (activationSpeed) { case FastActivation: probedelay = (mDNSs32)0; numannounce = InitialAnnounceCount; LogMsg("mDNS_RegisterInterface: Using fast activation for DirectLink interface %s (%#a)", set->ifname, &set->ip); break; case SlowActivation: probedelay = mDNSPlatformOneSecond * 5; numannounce = (mDNSu8)1; LogMsg("mDNS_RegisterInterface: Frequent transitions for interface %s (%#a), doing slow activation", set->ifname, &set->ip); m->mDNSStats.InterfaceUpFlap++; break; case NormalActivation: default: probedelay = mDNSPlatformOneSecond / 2; numannounce = InitialAnnounceCount; break; } LogInfo("mDNS_RegisterInterface: %s (%#a) probedelay %d", set->ifname, &set->ip, probedelay); // No probe or sending suppression on DirectLink type interfaces. if (activationSpeed == FastActivation) { m->SuppressSending = 0; m->SuppressProbes = 0; } else { // Use a small amount of randomness: // In the case of a network administrator turning on an Ethernet hub so that all the // connected machines establish link at exactly the same time, we don't want them all // to go and hit the network with identical queries at exactly the same moment. // We set a random delay of up to InitialQuestionInterval (1/3 second). // We must *never* set m->SuppressSending to more than that (or set it repeatedly in a way // that causes mDNSResponder to remain in a prolonged state of SuppressSending, because // suppressing packet sending for more than about 1/3 second can cause protocol correctness // to start to break down (e.g. we don't answer probes fast enough, and get name conflicts). // See mDNS: m->SuppressSending set too enthusiastically if (!m->SuppressSending) m->SuppressSending = m->timenow + (mDNSs32)mDNSRandom((mDNSu32)InitialQuestionInterval); if (m->SuppressProbes == 0 || m->SuppressProbes - NonZeroTime(m->timenow + probedelay) < 0) m->SuppressProbes = NonZeroTime(m->timenow + probedelay); } // Include OWNER option in packets for 60 seconds after connecting to the network. Setting // it here also handles the wake up case as the network link comes UP after waking causing // us to reconnect to the network. If we do this as part of the wake up code, it is possible // that the network link comes UP after 60 seconds and we never set the OWNER option m->AnnounceOwner = NonZeroTime(m->timenow + 60 * mDNSPlatformOneSecond); LogInfo("mDNS_RegisterInterface: Setting AnnounceOwner"); m->mDNSStats.InterfaceUp++; for (q = m->Questions; q; q=q->next) // Scan our list of questions { if (mDNSOpaque16IsZero(q->TargetQID)) { if (!q->InterfaceID || q->InterfaceID == set->InterfaceID) // If non-specific Q, or Q on this specific interface, { // then reactivate this question // If flapping, delay between first and second queries is nine seconds instead of one second mDNSBool dodelay = (activationSpeed == SlowActivation) && (q->FlappingInterface1 == set->InterfaceID || q->FlappingInterface2 == set->InterfaceID); mDNSs32 initial = dodelay ? InitialQuestionInterval * QuestionIntervalStep2 : InitialQuestionInterval; mDNSs32 qdelay = dodelay ? kDefaultQueryDelayTimeForFlappingInterface : 0; if (dodelay) LogInfo("No cache records expired for %##s (%s); delaying questions by %d seconds", q->qname.c, DNSTypeName(q->qtype), qdelay); if (!q->ThisQInterval || q->ThisQInterval > initial) { q->ThisQInterval = initial; q->RequestUnicast = kDefaultRequestUnicastCount; } q->LastQTime = m->timenow - q->ThisQInterval + qdelay; q->RecentAnswerPkts = 0; // Change the salt ReInitAnonInfo(&q->AnonInfo, &q->qname); SetNextQueryTime(m,q); } } } // For all our non-specific authoritative resource records (and any dormant records specific to this interface) // we now need them to re-probe if necessary, and then re-announce. for (rr = m->ResourceRecords; rr; rr=rr->next) { if (!rr->resrec.InterfaceID || rr->resrec.InterfaceID == set->InterfaceID) { // Change the salt ReInitAnonInfo(&rr->resrec.AnonInfo, rr->resrec.name); mDNSCoreRestartRegistration(m, rr, numannounce); } } #if APPLE_OSX_mDNSResponder && !TARGET_OS_IPHONE DNSSECProbe(m); #endif } RestartRecordGetZoneData(m); mDNS_UpdateAllowSleep(m); mDNS_Unlock(m); return(mStatus_NoError); } // Note: mDNS_DeregisterInterface calls mDNS_Deregister_internal which can call a user callback, which may change // the record list and/or question list. // Any code walking either list must use the CurrentQuestion and/or CurrentRecord mechanism to protect against this. mDNSexport void mDNS_DeregisterInterface(mDNS *const m, NetworkInterfaceInfo *set, InterfaceActivationSpeed activationSpeed) { NetworkInterfaceInfo **p = &m->HostInterfaces; mDNSBool revalidate = mDNSfalse; NetworkInterfaceInfo *primary; NetworkInterfaceInfo *intf; AuthRecord *A; mDNS_Lock(m); // Find this record in our list while (*p && *p != set) p=&(*p)->next; if (!*p) { debugf("mDNS_DeregisterInterface: NetworkInterfaceInfo not found in list"); mDNS_Unlock(m); return; } mDNS_DeactivateNetWake_internal(m, set); // Unlink this record from our list *p = (*p)->next; set->next = mDNSNULL; if (!set->InterfaceActive) { // If this interface not the active member of its set, update the v4/v6Available flags for the active member for (intf = m->HostInterfaces; intf; intf = intf->next) if (intf->InterfaceActive && intf->InterfaceID == set->InterfaceID) UpdateInterfaceProtocols(m, intf); } else { intf = FirstInterfaceForID(m, set->InterfaceID); if (intf) { LogInfo("mDNS_DeregisterInterface: Another representative of InterfaceID %d %s (%#a) exists;" " making it active", IID(set->InterfaceID), set->ifname, &set->ip); if (intf->InterfaceActive) LogMsg("mDNS_DeregisterInterface: ERROR intf->InterfaceActive already set for %s (%#a)", set->ifname, &set->ip); intf->InterfaceActive = mDNStrue; UpdateInterfaceProtocols(m, intf); if (intf->NetWake) mDNS_ActivateNetWake_internal(m, intf); // See if another representative *of the same type* exists. If not, we mave have gone from // dual-stack to v6-only (or v4-only) so we need to reconfirm which records are still valid. for (intf = m->HostInterfaces; intf; intf = intf->next) if (intf->InterfaceID == set->InterfaceID && intf->ip.type == set->ip.type) break; if (!intf) revalidate = mDNStrue; } else { mDNSu32 slot; CacheGroup *cg; CacheRecord *rr; DNSQuestion *q; LogInfo("mDNS_DeregisterInterface: Last representative of InterfaceID %d %s (%#a) deregistered;" " marking questions etc. dormant", IID(set->InterfaceID), set->ifname, &set->ip); m->mDNSStats.InterfaceDown++; if (set->McastTxRx && (activationSpeed == SlowActivation)) { LogMsg("mDNS_DeregisterInterface: Frequent transitions for interface %s (%#a)", set->ifname, &set->ip); m->mDNSStats.InterfaceDownFlap++; } // 1. Deactivate any questions specific to this interface, and tag appropriate questions // so that mDNS_RegisterInterface() knows how swiftly it needs to reactivate them for (q = m->Questions; q; q=q->next) { if (q->InterfaceID == set->InterfaceID) q->ThisQInterval = 0; if (!q->InterfaceID || q->InterfaceID == set->InterfaceID) { q->FlappingInterface2 = q->FlappingInterface1; q->FlappingInterface1 = set->InterfaceID; // Keep history of the last two interfaces to go away } } // 2. Flush any cache records received on this interface revalidate = mDNSfalse; // Don't revalidate if we're flushing the records FORALL_CACHERECORDS(slot, cg, rr) { if (rr->resrec.InterfaceID == set->InterfaceID) { // If this interface is deemed flapping, // postpone deleting the cache records in case the interface comes back again if (set->McastTxRx && (activationSpeed == SlowActivation)) { // For a flapping interface we want these records to go away after // kDefaultReconfirmTimeForFlappingInterface seconds if they are not reconfirmed. mDNS_Reconfirm_internal(m, rr, kDefaultReconfirmTimeForFlappingInterface); // We set UnansweredQueries = MaxUnansweredQueries so we don't waste time doing any queries for them -- // if the interface does come back, any relevant questions will be reactivated anyway rr->UnansweredQueries = MaxUnansweredQueries; } else { mDNS_PurgeCacheResourceRecord(m, rr); } } } } } // If we still have address records referring to this one, update them. // This is safe, because this NetworkInterfaceInfo has already been unlinked from the list, // so the call to FindFirstAdvertisedInterface() won’t accidentally find it. primary = FindFirstAdvertisedInterface(m); A = primary ? &primary->RR_A : mDNSNULL; for (intf = m->HostInterfaces; intf; intf = intf->next) if (intf->RR_A.RRSet == &set->RR_A) intf->RR_A.RRSet = A; // If we were advertising on this interface, deregister those address and reverse-lookup records now if (set->Advertise) DeadvertiseInterface(m, set); // If we have any cache records received on this interface that went away, then re-verify them. // In some versions of OS X the IPv6 address remains on an interface even when the interface is turned off, // giving the false impression that there's an active representative of this interface when there really isn't. // Don't need to do this when shutting down, because *all* interfaces are about to go away if (revalidate && !m->ShutdownTime) { mDNSu32 slot; CacheGroup *cg; CacheRecord *rr; FORALL_CACHERECORDS(slot, cg, rr) if (rr->resrec.InterfaceID == set->InterfaceID) mDNS_Reconfirm_internal(m, rr, kDefaultReconfirmTimeForFlappingInterface); } mDNS_UpdateAllowSleep(m); mDNS_Unlock(m); } mDNSlocal void SetAnonInfoSRS(ServiceRecordSet *sr, int NumSubTypes) { int i, len; if (!sr->AnonData) return; len = mDNSPlatformStrLen(sr->AnonData); if (sr->RR_PTR.resrec.AnonInfo) { LogMsg("SetAnonInfoSRS: Freeing AnonInfo for PTR record %##s, should have been freed already", sr->RR_PTR.resrec.name->c); FreeAnonInfo(sr->RR_PTR.resrec.AnonInfo); } sr->RR_PTR.resrec.AnonInfo = AllocateAnonInfo(sr->RR_PTR.resrec.name, sr->AnonData, len, mDNSNULL); for (i=0; iSubTypes[i].resrec.AnonInfo) { LogMsg("SetAnonInfoSRS: Freeing AnonInfo for subtype record %##s, should have been freed already", sr->SubTypes[i].resrec.name->c); FreeAnonInfo(sr->SubTypes[i].resrec.AnonInfo); } sr->SubTypes[i].resrec.AnonInfo = AllocateAnonInfo(sr->SubTypes[i].resrec.name, sr->AnonData, len, mDNSNULL); } } mDNSlocal void ResetAnonInfoSRS(ServiceRecordSet *sr, int NumSubTypes) { int i; if (!sr->AnonData) return; if (sr->RR_PTR.resrec.AnonInfo) { FreeAnonInfo(sr->RR_PTR.resrec.AnonInfo); sr->RR_PTR.resrec.AnonInfo = mDNSNULL; } for (i=0; iSubTypes[i].resrec.AnonInfo) { FreeAnonInfo(sr->SubTypes[i].resrec.AnonInfo); sr->SubTypes[i].resrec.AnonInfo = mDNSNULL; } } } mDNSlocal void ServiceCallback(mDNS *const m, AuthRecord *const rr, mStatus result) { ServiceRecordSet *sr = (ServiceRecordSet *)rr->RecordContext; (void)m; // Unused parameter #if MDNS_DEBUGMSGS { char *msg = "Unknown result"; if (result == mStatus_NoError) msg = "Name Registered"; else if (result == mStatus_NameConflict) msg = "Name Conflict"; else if (result == mStatus_MemFree) msg = "Memory Free"; debugf("ServiceCallback: %##s (%s) %s (%d)", rr->resrec.name->c, DNSTypeName(rr->resrec.rrtype), msg, result); } #endif // Only pass on the NoError acknowledgement for the SRV record (when it finishes probing) if (result == mStatus_NoError && rr != &sr->RR_SRV) return; // If we got a name conflict on either SRV or TXT, forcibly deregister this service, and record that we did that if (result == mStatus_NameConflict) { sr->Conflict = mDNStrue; // Record that this service set had a conflict mDNS_DeregisterService(m, sr); // Unlink the records from our list return; } if (result == mStatus_MemFree) { // If the SRV/TXT/PTR records, or the _services._dns-sd._udp record, or any of the subtype PTR records, // are still in the process of deregistering, don't pass on the NameConflict/MemFree message until // every record is finished cleaning up. mDNSu32 i; ExtraResourceRecord *e = sr->Extras; if (sr->RR_SRV.resrec.RecordType != kDNSRecordTypeUnregistered) return; if (sr->RR_TXT.resrec.RecordType != kDNSRecordTypeUnregistered) return; if (sr->RR_PTR.resrec.RecordType != kDNSRecordTypeUnregistered) return; if (sr->RR_ADV.resrec.RecordType != kDNSRecordTypeUnregistered) return; for (i=0; iNumSubTypes; i++) if (sr->SubTypes[i].resrec.RecordType != kDNSRecordTypeUnregistered) return; while (e) { if (e->r.resrec.RecordType != kDNSRecordTypeUnregistered) return; e = e->next; } ResetAnonInfoSRS(sr, sr->NumSubTypes); // If this ServiceRecordSet was forcibly deregistered, and now its memory is ready for reuse, // then we can now report the NameConflict to the client if (sr->Conflict) result = mStatus_NameConflict; } LogInfo("ServiceCallback: All records %s for %##s", (result == mStatus_MemFree ? "Unregistered" : "Registered"), sr->RR_PTR.resrec.name->c); // CAUTION: MUST NOT do anything more with sr after calling sr->Callback(), because the client's callback // function is allowed to do anything, including deregistering this service and freeing its memory. if (sr->ServiceCallback) sr->ServiceCallback(m, sr, result); } mDNSlocal void NSSCallback(mDNS *const m, AuthRecord *const rr, mStatus result) { ServiceRecordSet *sr = (ServiceRecordSet *)rr->RecordContext; if (sr->ServiceCallback) sr->ServiceCallback(m, sr, result); } // Derive AuthRecType from the kDNSServiceFlags* values. mDNSlocal AuthRecType setAuthRecType(mDNSInterfaceID InterfaceID, mDNSu32 flags) { AuthRecType artype; if (InterfaceID == mDNSInterface_LocalOnly) artype = AuthRecordLocalOnly; else if (InterfaceID == mDNSInterface_P2P || InterfaceID == mDNSInterface_BLE) artype = AuthRecordP2P; else if ((InterfaceID == mDNSInterface_Any) && (flags & kDNSServiceFlagsIncludeP2P) && (flags & kDNSServiceFlagsIncludeAWDL)) artype = AuthRecordAnyIncludeAWDLandP2P; else if ((InterfaceID == mDNSInterface_Any) && (flags & kDNSServiceFlagsIncludeP2P)) artype = AuthRecordAnyIncludeP2P; else if ((InterfaceID == mDNSInterface_Any) && (flags & kDNSServiceFlagsIncludeAWDL)) artype = AuthRecordAnyIncludeAWDL; else artype = AuthRecordAny; return artype; } // Used to derive the original D2D specific flags specified by the client in the registration // when we don't have access to the original flag (kDNSServiceFlags*) values. mDNSexport mDNSu32 deriveD2DFlagsFromAuthRecType(AuthRecType authRecType) { mDNSu32 flags = 0; if ((authRecType == AuthRecordAnyIncludeP2P) || (authRecType == AuthRecordAnyIncludeAWDLandP2P)) flags |= kDNSServiceFlagsIncludeP2P; else if ((authRecType == AuthRecordAnyIncludeAWDL) || (authRecType == AuthRecordAnyIncludeAWDLandP2P)) flags |= kDNSServiceFlagsIncludeAWDL; return flags; } // Note: // Name is first label of domain name (any dots in the name are actual dots, not label separators) // Type is service type (e.g. "_ipp._tcp.") // Domain is fully qualified domain name (i.e. ending with a null label) // We always register a TXT, even if it is empty (so that clients are not // left waiting forever looking for a nonexistent record.) // If the host parameter is mDNSNULL or the root domain (ASCII NUL), // then the default host name (m->MulticastHostname) is automatically used // If the optional target host parameter is set, then the storage it points to must remain valid for the lifetime of the service registration mDNSexport mStatus mDNS_RegisterService(mDNS *const m, ServiceRecordSet *sr, const domainlabel *const name, const domainname *const type, const domainname *const domain, const domainname *const host, mDNSIPPort port, const mDNSu8 txtinfo[], mDNSu16 txtlen, AuthRecord *SubTypes, mDNSu32 NumSubTypes, mDNSInterfaceID InterfaceID, mDNSServiceCallback Callback, void *Context, mDNSu32 flags) { mStatus err; mDNSu32 i; mDNSu32 hostTTL; AuthRecType artype; mDNSu8 recordType = (flags & kDNSServiceFlagsKnownUnique) ? kDNSRecordTypeKnownUnique : kDNSRecordTypeUnique; sr->ServiceCallback = Callback; sr->ServiceContext = Context; sr->Conflict = mDNSfalse; sr->Extras = mDNSNULL; sr->NumSubTypes = NumSubTypes; sr->SubTypes = SubTypes; sr->flags = flags; artype = setAuthRecType(InterfaceID, flags); // Initialize the AuthRecord objects to sane values // Need to initialize everything correctly *before* making the decision whether to do a RegisterNoSuchService and bail out mDNS_SetupResourceRecord(&sr->RR_ADV, mDNSNULL, InterfaceID, kDNSType_PTR, kStandardTTL, kDNSRecordTypeAdvisory, artype, ServiceCallback, sr); mDNS_SetupResourceRecord(&sr->RR_PTR, mDNSNULL, InterfaceID, kDNSType_PTR, kStandardTTL, kDNSRecordTypeShared, artype, ServiceCallback, sr); if (flags & kDNSServiceFlagsWakeOnlyService) { sr->RR_PTR.AuthFlags = AuthFlagsWakeOnly; } if (SameDomainName(type, (const domainname *) "\x4" "_ubd" "\x4" "_tcp")) hostTTL = kHostNameSmallTTL; else hostTTL = kHostNameTTL; mDNS_SetupResourceRecord(&sr->RR_SRV, mDNSNULL, InterfaceID, kDNSType_SRV, hostTTL, recordType, artype, ServiceCallback, sr); mDNS_SetupResourceRecord(&sr->RR_TXT, mDNSNULL, InterfaceID, kDNSType_TXT, kStandardTTL, recordType, artype, ServiceCallback, sr); // If port number is zero, that means the client is really trying to do a RegisterNoSuchService if (mDNSIPPortIsZero(port)) return(mDNS_RegisterNoSuchService(m, &sr->RR_SRV, name, type, domain, mDNSNULL, InterfaceID, NSSCallback, sr, flags)); // If the caller is registering an oversized TXT record, // it is the caller's responsibility to allocate a ServiceRecordSet structure that is large enough for it if (sr->RR_TXT.resrec.rdata->MaxRDLength < txtlen) sr->RR_TXT.resrec.rdata->MaxRDLength = txtlen; // Set up the record names // For now we only create an advisory record for the main type, not for subtypes // We need to gain some operational experience before we decide if there's a need to create them for subtypes too if (ConstructServiceName(&sr->RR_ADV.namestorage, (const domainlabel*)"\x09_services", (const domainname*)"\x07_dns-sd\x04_udp", domain) == mDNSNULL) return(mStatus_BadParamErr); if (ConstructServiceName(&sr->RR_PTR.namestorage, mDNSNULL, type, domain) == mDNSNULL) return(mStatus_BadParamErr); if (ConstructServiceName(&sr->RR_SRV.namestorage, name, type, domain) == mDNSNULL) return(mStatus_BadParamErr); AssignDomainName(&sr->RR_TXT.namestorage, sr->RR_SRV.resrec.name); // 1. Set up the ADV record rdata to advertise our service type AssignDomainName(&sr->RR_ADV.resrec.rdata->u.name, sr->RR_PTR.resrec.name); // 2. Set up the PTR record rdata to point to our service name // We set up two additionals, so when a client asks for this PTR we automatically send the SRV and the TXT too // Note: uDNS registration code assumes that Additional1 points to the SRV record AssignDomainName(&sr->RR_PTR.resrec.rdata->u.name, sr->RR_SRV.resrec.name); sr->RR_PTR.Additional1 = &sr->RR_SRV; sr->RR_PTR.Additional2 = &sr->RR_TXT; // 2a. Set up any subtype PTRs to point to our service name // If the client is using subtypes, it is the client's responsibility to have // already set the first label of the record name to the subtype being registered for (i=0; iSubTypes[i].resrec.name); st.c[1+st.c[0]] = 0; // Only want the first label, not the whole FQDN (particularly for mDNS_RenameAndReregisterService()) AppendDomainName(&st, type); mDNS_SetupResourceRecord(&sr->SubTypes[i], mDNSNULL, InterfaceID, kDNSType_PTR, kStandardTTL, kDNSRecordTypeShared, artype, ServiceCallback, sr); if (ConstructServiceName(&sr->SubTypes[i].namestorage, mDNSNULL, &st, domain) == mDNSNULL) return(mStatus_BadParamErr); AssignDomainName(&sr->SubTypes[i].resrec.rdata->u.name, &sr->RR_SRV.namestorage); sr->SubTypes[i].Additional1 = &sr->RR_SRV; sr->SubTypes[i].Additional2 = &sr->RR_TXT; } SetAnonInfoSRS(sr, NumSubTypes); // 3. Set up the SRV record rdata. sr->RR_SRV.resrec.rdata->u.srv.priority = 0; sr->RR_SRV.resrec.rdata->u.srv.weight = 0; sr->RR_SRV.resrec.rdata->u.srv.port = port; // Setting AutoTarget tells DNS that the target of this SRV is to be automatically kept in sync with our host name if (host && host->c[0]) AssignDomainName(&sr->RR_SRV.resrec.rdata->u.srv.target, host); else { sr->RR_SRV.AutoTarget = Target_AutoHost; sr->RR_SRV.resrec.rdata->u.srv.target.c[0] = '\0'; } // 4. Set up the TXT record rdata, // and set DependentOn because we're depending on the SRV record to find and resolve conflicts for us // Note: uDNS registration code assumes that DependentOn points to the SRV record if (txtinfo == mDNSNULL) sr->RR_TXT.resrec.rdlength = 0; else if (txtinfo != sr->RR_TXT.resrec.rdata->u.txt.c) { sr->RR_TXT.resrec.rdlength = txtlen; if (sr->RR_TXT.resrec.rdlength > sr->RR_TXT.resrec.rdata->MaxRDLength) return(mStatus_BadParamErr); mDNSPlatformMemCopy(sr->RR_TXT.resrec.rdata->u.txt.c, txtinfo, txtlen); } sr->RR_TXT.DependentOn = &sr->RR_SRV; mDNS_Lock(m); // It is important that we register SRV first. uDNS assumes that SRV is registered first so // that if the SRV cannot find a target, rest of the records that belong to this service // will not be activated. err = mDNS_Register_internal(m, &sr->RR_SRV); // If we can't register the SRV record due to errors, bail out. It has not been inserted in // any list and hence no need to deregister. We could probably do similar checks for other // records below and bail out. For now, this seems to be sufficient to address rdar://9304275 if (err) { mDNS_Unlock(m); return err; } if (!err) err = mDNS_Register_internal(m, &sr->RR_TXT); // We register the RR_PTR last, because we want to be sure that in the event of a forced call to // mDNS_StartExit, the RR_PTR will be the last one to be forcibly deregistered, since that is what triggers // the mStatus_MemFree callback to ServiceCallback, which in turn passes on the mStatus_MemFree back to // the client callback, which is then at liberty to free the ServiceRecordSet memory at will. We need to // make sure we've deregistered all our records and done any other necessary cleanup before that happens. if (!err) err = mDNS_Register_internal(m, &sr->RR_ADV); for (i=0; iSubTypes[i]); if (!err) err = mDNS_Register_internal(m, &sr->RR_PTR); mDNS_Unlock(m); if (err) mDNS_DeregisterService(m, sr); return(err); } mDNSexport mStatus mDNS_AddRecordToService(mDNS *const m, ServiceRecordSet *sr, ExtraResourceRecord *extra, RData *rdata, mDNSu32 ttl, mDNSu32 flags) { ExtraResourceRecord **e; mStatus status; AuthRecType artype; mDNSInterfaceID InterfaceID = sr->RR_PTR.resrec.InterfaceID; ResourceRecord *rr; artype = setAuthRecType(InterfaceID, flags); extra->next = mDNSNULL; mDNS_SetupResourceRecord(&extra->r, rdata, sr->RR_PTR.resrec.InterfaceID, extra->r.resrec.rrtype, ttl, kDNSRecordTypeUnique, artype, ServiceCallback, sr); AssignDomainName(&extra->r.namestorage, sr->RR_SRV.resrec.name); mDNS_Lock(m); rr = mDNSNULL; if (extra->r.resrec.rrtype == kDNSType_TXT) { if (sr->RR_TXT.resrec.RecordType & kDNSRecordTypeUniqueMask) rr = &sr->RR_TXT.resrec; } else if (extra->r.resrec.rrtype == kDNSType_SRV) { if (sr->RR_SRV.resrec.RecordType & kDNSRecordTypeUniqueMask) rr = &sr->RR_SRV.resrec; } if (!rr) { ExtraResourceRecord *srExtra; for (srExtra = sr->Extras; srExtra; srExtra = srExtra->next) { if ((srExtra->r.resrec.rrtype == extra->r.resrec.rrtype) && (srExtra->r.resrec.RecordType & kDNSRecordTypeUniqueMask)) { rr = &srExtra->r.resrec; break; } } } if (rr && (extra->r.resrec.rroriginalttl != rr->rroriginalttl)) { LogMsg("mDNS_AddRecordToService: Correcting TTL from %4d to %4d for %s", extra->r.resrec.rroriginalttl, rr->rroriginalttl, RRDisplayString(m, &extra->r.resrec)); extra->r.resrec.rroriginalttl = rr->rroriginalttl; } e = &sr->Extras; while (*e) e = &(*e)->next; extra->r.DependentOn = &sr->RR_SRV; debugf("mDNS_AddRecordToService adding record to %##s %s %d", extra->r.resrec.name->c, DNSTypeName(extra->r.resrec.rrtype), extra->r.resrec.rdlength); status = mDNS_Register_internal(m, &extra->r); if (status == mStatus_NoError) *e = extra; mDNS_Unlock(m); return(status); } mDNSexport mStatus mDNS_RemoveRecordFromService(mDNS *const m, ServiceRecordSet *sr, ExtraResourceRecord *extra, mDNSRecordCallback MemFreeCallback, void *Context) { ExtraResourceRecord **e; mStatus status; mDNS_Lock(m); e = &sr->Extras; while (*e && *e != extra) e = &(*e)->next; if (!*e) { debugf("mDNS_RemoveRecordFromService failed to remove record from %##s", extra->r.resrec.name->c); status = mStatus_BadReferenceErr; } else { debugf("mDNS_RemoveRecordFromService removing record from %##s", extra->r.resrec.name->c); extra->r.RecordCallback = MemFreeCallback; extra->r.RecordContext = Context; *e = (*e)->next; status = mDNS_Deregister_internal(m, &extra->r, mDNS_Dereg_normal); } mDNS_Unlock(m); return(status); } mDNSexport mStatus mDNS_RenameAndReregisterService(mDNS *const m, ServiceRecordSet *const sr, const domainlabel *newname) { // Note: Don't need to use mDNS_Lock(m) here, because this code is just using public routines // mDNS_RegisterService() and mDNS_AddRecordToService(), which do the right locking internally. domainlabel name1, name2; domainname type, domain; const domainname *host = sr->RR_SRV.AutoTarget ? mDNSNULL : &sr->RR_SRV.resrec.rdata->u.srv.target; ExtraResourceRecord *extras = sr->Extras; mStatus err; DeconstructServiceName(sr->RR_SRV.resrec.name, &name1, &type, &domain); if (!newname) { name2 = name1; IncrementLabelSuffix(&name2, mDNStrue); newname = &name2; } if (SameDomainName(&domain, &localdomain)) debugf("%##s service renamed from \"%#s\" to \"%#s\"", type.c, name1.c, newname->c); else debugf("%##s service (domain %##s) renamed from \"%#s\" to \"%#s\"",type.c, domain.c, name1.c, newname->c); err = mDNS_RegisterService(m, sr, newname, &type, &domain, host, sr->RR_SRV.resrec.rdata->u.srv.port, sr->RR_TXT.resrec.rdata->u.txt.c, sr->RR_TXT.resrec.rdlength, sr->SubTypes, sr->NumSubTypes, sr->RR_PTR.resrec.InterfaceID, sr->ServiceCallback, sr->ServiceContext, sr->flags); // mDNS_RegisterService() just reset sr->Extras to NULL. // Fortunately we already grabbed ourselves a copy of this pointer (above), so we can now run // through the old list of extra records, and re-add them to our freshly created service registration while (!err && extras) { ExtraResourceRecord *e = extras; extras = extras->next; err = mDNS_AddRecordToService(m, sr, e, e->r.resrec.rdata, e->r.resrec.rroriginalttl, 0); } return(err); } // Note: mDNS_DeregisterService calls mDNS_Deregister_internal which can call a user callback, // which may change the record list and/or question list. // Any code walking either list must use the CurrentQuestion and/or CurrentRecord mechanism to protect against this. mDNSexport mStatus mDNS_DeregisterService_drt(mDNS *const m, ServiceRecordSet *sr, mDNS_Dereg_type drt) { // If port number is zero, that means this was actually registered using mDNS_RegisterNoSuchService() if (mDNSIPPortIsZero(sr->RR_SRV.resrec.rdata->u.srv.port)) return(mDNS_DeregisterNoSuchService(m, &sr->RR_SRV)); if (sr->RR_PTR.resrec.RecordType == kDNSRecordTypeUnregistered) { debugf("Service set for %##s already deregistered", sr->RR_SRV.resrec.name->c); return(mStatus_BadReferenceErr); } else if (sr->RR_PTR.resrec.RecordType == kDNSRecordTypeDeregistering) { LogInfo("Service set for %##s already in the process of deregistering", sr->RR_SRV.resrec.name->c); // Avoid race condition: // If a service gets a conflict, then we set the Conflict flag to tell us to generate // an mStatus_NameConflict message when we get the mStatus_MemFree for our PTR record. // If the client happens to deregister the service in the middle of that process, then // we clear the flag back to the normal state, so that we deliver a plain mStatus_MemFree // instead of incorrectly promoting it to mStatus_NameConflict. // This race condition is exposed particularly when the conformance test generates // a whole batch of simultaneous conflicts across a range of services all advertised // using the same system default name, and if we don't take this precaution then // we end up incrementing m->nicelabel multiple times instead of just once. // Bug when auto-renaming Computer Name after name collision sr->Conflict = mDNSfalse; return(mStatus_NoError); } else { mDNSu32 i; mStatus status; ExtraResourceRecord *e; mDNS_Lock(m); e = sr->Extras; // We use mDNS_Dereg_repeat because, in the event of a collision, some or all of the // SRV, TXT, or Extra records could have already been automatically deregistered, and that's okay mDNS_Deregister_internal(m, &sr->RR_SRV, mDNS_Dereg_repeat); mDNS_Deregister_internal(m, &sr->RR_TXT, mDNS_Dereg_repeat); mDNS_Deregister_internal(m, &sr->RR_ADV, drt); // We deregister all of the extra records, but we leave the sr->Extras list intact // in case the client wants to do a RenameAndReregister and reinstate the registration while (e) { mDNS_Deregister_internal(m, &e->r, mDNS_Dereg_repeat); e = e->next; } for (i=0; iNumSubTypes; i++) mDNS_Deregister_internal(m, &sr->SubTypes[i], drt); status = mDNS_Deregister_internal(m, &sr->RR_PTR, drt); mDNS_Unlock(m); return(status); } } // Create a registration that asserts that no such service exists with this name. // This can be useful where there is a given function is available through several protocols. // For example, a printer called "Stuart's Printer" may implement printing via the "pdl-datastream" and "IPP" // protocols, but not via "LPR". In this case it would be prudent for the printer to assert the non-existence of an // "LPR" service called "Stuart's Printer". Without this precaution, another printer than offers only "LPR" printing // could inadvertently advertise its service under the same name "Stuart's Printer", which might be confusing for users. mDNSexport mStatus mDNS_RegisterNoSuchService(mDNS *const m, AuthRecord *const rr, const domainlabel *const name, const domainname *const type, const domainname *const domain, const domainname *const host, const mDNSInterfaceID InterfaceID, mDNSRecordCallback Callback, void *Context, mDNSu32 flags) { AuthRecType artype; artype = setAuthRecType(InterfaceID, flags); mDNS_SetupResourceRecord(rr, mDNSNULL, InterfaceID, kDNSType_SRV, kHostNameTTL, kDNSRecordTypeUnique, artype, Callback, Context); if (ConstructServiceName(&rr->namestorage, name, type, domain) == mDNSNULL) return(mStatus_BadParamErr); rr->resrec.rdata->u.srv.priority = 0; rr->resrec.rdata->u.srv.weight = 0; rr->resrec.rdata->u.srv.port = zeroIPPort; if (host && host->c[0]) AssignDomainName(&rr->resrec.rdata->u.srv.target, host); else rr->AutoTarget = Target_AutoHost; return(mDNS_Register(m, rr)); } mDNSexport mStatus mDNS_AdvertiseDomains(mDNS *const m, AuthRecord *rr, mDNS_DomainType DomainType, const mDNSInterfaceID InterfaceID, char *domname) { AuthRecType artype; if (InterfaceID == mDNSInterface_LocalOnly) artype = AuthRecordLocalOnly; else if (InterfaceID == mDNSInterface_P2P || InterfaceID == mDNSInterface_BLE) artype = AuthRecordP2P; else artype = AuthRecordAny; mDNS_SetupResourceRecord(rr, mDNSNULL, InterfaceID, kDNSType_PTR, kStandardTTL, kDNSRecordTypeShared, artype, mDNSNULL, mDNSNULL); if (!MakeDomainNameFromDNSNameString(&rr->namestorage, mDNS_DomainTypeNames[DomainType])) return(mStatus_BadParamErr); if (!MakeDomainNameFromDNSNameString(&rr->resrec.rdata->u.name, domname)) return(mStatus_BadParamErr); return(mDNS_Register(m, rr)); } mDNSlocal mDNSBool mDNS_IdUsedInResourceRecordsList(mDNS * const m, mDNSOpaque16 id) { AuthRecord *r; for (r = m->ResourceRecords; r; r=r->next) if (mDNSSameOpaque16(id, r->updateid)) return mDNStrue; return mDNSfalse; } mDNSlocal mDNSBool mDNS_IdUsedInQuestionsList(mDNS * const m, mDNSOpaque16 id) { DNSQuestion *q; for (q = m->Questions; q; q=q->next) if (mDNSSameOpaque16(id, q->TargetQID)) return mDNStrue; return mDNSfalse; } mDNSexport mDNSOpaque16 mDNS_NewMessageID(mDNS * const m) { mDNSOpaque16 id; int i; for (i=0; i<10; i++) { id = mDNSOpaque16fromIntVal(1 + (mDNSu16)mDNSRandom(0xFFFE)); if (!mDNS_IdUsedInResourceRecordsList(m, id) && !mDNS_IdUsedInQuestionsList(m, id)) break; } debugf("mDNS_NewMessageID: %5d", mDNSVal16(id)); return id; } // *************************************************************************** #if COMPILER_LIKES_PRAGMA_MARK #pragma mark - #pragma mark - Sleep Proxy Server #endif mDNSlocal void RestartARPProbing(mDNS *const m, AuthRecord *const rr) { // If we see an ARP from a machine we think is sleeping, then either // (i) the machine has woken, or // (ii) it's just a stray old packet from before the machine slept // To handle the second case, we reset ProbeCount, so we'll suppress our own answers for a while, to avoid // generating ARP conflicts with a waking machine, and set rr->LastAPTime so we'll start probing again in 10 seconds. // If the machine has just woken then we'll discard our records when we see the first new mDNS probe from that machine. // If it was a stray old packet, then after 10 seconds we'll probe again and then start answering ARPs again. In this case we *do* // need to send new ARP Announcements, because the owner's ARP broadcasts will have updated neighboring ARP caches, so we need to // re-assert our (temporary) ownership of that IP address in order to receive subsequent packets addressed to that IPv4 address. rr->resrec.RecordType = kDNSRecordTypeUnique; rr->ProbeCount = DefaultProbeCountForTypeUnique; rr->ProbeRestartCount++; // If we haven't started announcing yet (and we're not already in ten-second-delay mode) the machine is probably // still going to sleep, so we just reset rr->ProbeCount so we'll continue probing until it stops responding. // If we *have* started announcing, the machine is probably in the process of waking back up, so in that case // we're more cautious and we wait ten seconds before probing it again. We do this because while waking from // sleep, some network interfaces tend to lose or delay inbound packets, and without this delay, if the waking machine // didn't answer our three probes within three seconds then we'd announce and cause it an unnecessary address conflict. if (rr->AnnounceCount == InitialAnnounceCount && m->timenow - rr->LastAPTime >= 0) InitializeLastAPTime(m, rr); else { rr->AnnounceCount = InitialAnnounceCount; rr->ThisAPInterval = mDNSPlatformOneSecond; rr->LastAPTime = m->timenow + mDNSPlatformOneSecond * 9; // Send first packet at rr->LastAPTime + rr->ThisAPInterval, i.e. 10 seconds from now SetNextAnnounceProbeTime(m, rr); } } mDNSlocal void mDNSCoreReceiveRawARP(mDNS *const m, const ARP_EthIP *const arp, const mDNSInterfaceID InterfaceID) { static const mDNSOpaque16 ARP_op_request = { { 0, 1 } }; AuthRecord *rr; NetworkInterfaceInfo *intf = FirstInterfaceForID(m, InterfaceID); if (!intf) return; mDNS_Lock(m); // Pass 1: // Process ARP Requests and Probes (but not Announcements), and generate an ARP Reply if necessary. // We also process ARPs from our own kernel (and 'answer' them by injecting a local ARP table entry) // We ignore ARP Announcements here -- Announcements are not questions, they're assertions, so we don't need to answer them. // The times we might need to react to an ARP Announcement are: // (i) as an indication that the host in question has not gone to sleep yet (so we should delay beginning to proxy for it) or // (ii) if it's a conflicting Announcement from another host // -- and we check for these in Pass 2 below. if (mDNSSameOpaque16(arp->op, ARP_op_request) && !mDNSSameIPv4Address(arp->spa, arp->tpa)) { for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->resrec.InterfaceID == InterfaceID && rr->resrec.RecordType != kDNSRecordTypeDeregistering && rr->AddressProxy.type == mDNSAddrType_IPv4 && mDNSSameIPv4Address(rr->AddressProxy.ip.v4, arp->tpa)) { static const char msg1[] = "ARP Req from owner -- re-probing"; static const char msg2[] = "Ignoring ARP Request from "; static const char msg3[] = "Creating Local ARP Cache entry "; static const char msg4[] = "Answering ARP Request from "; const char *const msg = mDNSSameEthAddress(&arp->sha, &rr->WakeUp.IMAC) ? msg1 : (rr->AnnounceCount == InitialAnnounceCount) ? msg2 : mDNSSameEthAddress(&arp->sha, &intf->MAC) ? msg3 : msg4; LogMsg("Arp %-7s %s %.6a %.4a for %.4a -- H-MAC %.6a I-MAC %.6a %s", intf->ifname, msg, arp->sha.b, arp->spa.b, arp->tpa.b, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, ARDisplayString(m, rr)); if (msg == msg1) { if ( rr->ProbeRestartCount < MAX_PROBE_RESTARTS) RestartARPProbing(m, rr); else LogSPS("Reached maximum number of restarts for probing - %s", ARDisplayString(m,rr)); } else if (msg == msg3) { mDNSPlatformSetLocalAddressCacheEntry(&rr->AddressProxy, &rr->WakeUp.IMAC, InterfaceID); } else if (msg == msg4) { SendARP(m, 2, rr, (mDNSv4Addr *)arp->tpa.b, &arp->sha, (mDNSv4Addr *)arp->spa.b, &arp->sha); } } } // Pass 2: // For all types of ARP packet we check the Sender IP address to make sure it doesn't conflict with any AddressProxy record we're holding. // (Strictly speaking we're only checking Announcement/Request/Reply packets, since ARP Probes have zero Sender IP address, // so by definition (and by design) they can never conflict with any real (i.e. non-zero) IP address). // We ignore ARPs we sent ourselves (Sender MAC address is our MAC address) because our own proxy ARPs do not constitute a conflict that we need to handle. // If we see an apparently conflicting ARP, we check the sender hardware address: // If the sender hardware address is the original owner this is benign, so we just suppress our own proxy answering for a while longer. // If the sender hardware address is *not* the original owner, then this is a conflict, and we need to wake the sleeping machine to handle it. if (mDNSSameEthAddress(&arp->sha, &intf->MAC)) debugf("ARP from self for %.4a", arp->tpa.b); else { if (!mDNSSameIPv4Address(arp->spa, zerov4Addr)) for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->resrec.InterfaceID == InterfaceID && rr->resrec.RecordType != kDNSRecordTypeDeregistering && rr->AddressProxy.type == mDNSAddrType_IPv4 && mDNSSameIPv4Address(rr->AddressProxy.ip.v4, arp->spa) && (rr->ProbeRestartCount < MAX_PROBE_RESTARTS)) { if (mDNSSameEthAddress(&zeroEthAddr, &rr->WakeUp.HMAC)) { LogMsg("%-7s ARP from %.6a %.4a for %.4a -- Invalid H-MAC %.6a I-MAC %.6a %s", intf->ifname, arp->sha.b, arp->spa.b, arp->tpa.b, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, ARDisplayString(m, rr)); } else { RestartARPProbing(m, rr); if (mDNSSameEthAddress(&arp->sha, &rr->WakeUp.IMAC)) { LogMsg("%-7s ARP %s from owner %.6a %.4a for %-15.4a -- re-starting probing for %s", intf->ifname, mDNSSameIPv4Address(arp->spa, arp->tpa) ? "Announcement " : mDNSSameOpaque16(arp->op, ARP_op_request) ? "Request " : "Response ", arp->sha.b, arp->spa.b, arp->tpa.b, ARDisplayString(m, rr)); } else { LogMsg("%-7s Conflicting ARP from %.6a %.4a for %.4a -- waking H-MAC %.6a I-MAC %.6a %s", intf->ifname, arp->sha.b, arp->spa.b, arp->tpa.b, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, ARDisplayString(m, rr)); ScheduleWakeup(m, rr->resrec.InterfaceID, &rr->WakeUp.HMAC); } } } } mDNS_Unlock(m); } /* // Option 1 is Source Link Layer Address Option // Option 2 is Target Link Layer Address Option mDNSlocal const mDNSEthAddr *GetLinkLayerAddressOption(const IPv6NDP *const ndp, const mDNSu8 *const end, mDNSu8 op) { const mDNSu8 *options = (mDNSu8 *)(ndp+1); while (options < end) { debugf("NDP Option %02X len %2d %d", options[0], options[1], end - options); if (options[0] == op && options[1] == 1) return (const mDNSEthAddr*)(options+2); options += options[1] * 8; } return mDNSNULL; } */ mDNSlocal void mDNSCoreReceiveRawND(mDNS *const m, const mDNSEthAddr *const sha, const mDNSv6Addr *spa, const IPv6NDP *const ndp, const mDNSu8 *const end, const mDNSInterfaceID InterfaceID) { AuthRecord *rr; NetworkInterfaceInfo *intf = FirstInterfaceForID(m, InterfaceID); if (!intf) return; mDNS_Lock(m); // Pass 1: Process Neighbor Solicitations, and generate a Neighbor Advertisement if necessary. if (ndp->type == NDP_Sol) { //const mDNSEthAddr *const sha = GetLinkLayerAddressOption(ndp, end, NDP_SrcLL); (void)end; for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->resrec.InterfaceID == InterfaceID && rr->resrec.RecordType != kDNSRecordTypeDeregistering && rr->AddressProxy.type == mDNSAddrType_IPv6 && mDNSSameIPv6Address(rr->AddressProxy.ip.v6, ndp->target)) { static const char msg1[] = "NDP Req from owner -- re-probing"; static const char msg2[] = "Ignoring NDP Request from "; static const char msg3[] = "Creating Local NDP Cache entry "; static const char msg4[] = "Answering NDP Request from "; static const char msg5[] = "Answering NDP Probe from "; const char *const msg = sha && mDNSSameEthAddress(sha, &rr->WakeUp.IMAC) ? msg1 : (rr->AnnounceCount == InitialAnnounceCount) ? msg2 : sha && mDNSSameEthAddress(sha, &intf->MAC) ? msg3 : spa && mDNSIPv6AddressIsZero(*spa) ? msg4 : msg5; LogSPS("%-7s %s %.6a %.16a for %.16a -- H-MAC %.6a I-MAC %.6a %s", intf->ifname, msg, sha, spa, &ndp->target, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, ARDisplayString(m, rr)); if (msg == msg1) { if (rr->ProbeRestartCount < MAX_PROBE_RESTARTS) RestartARPProbing(m, rr); else LogSPS("Reached maximum number of restarts for probing - %s", ARDisplayString(m,rr)); } else if (msg == msg3) mDNSPlatformSetLocalAddressCacheEntry(&rr->AddressProxy, &rr->WakeUp.IMAC, InterfaceID); else if (msg == msg4) SendNDP(m, NDP_Adv, NDP_Solicited, rr, &ndp->target, mDNSNULL, spa, sha); else if (msg == msg5) SendNDP(m, NDP_Adv, 0, rr, &ndp->target, mDNSNULL, &AllHosts_v6, &AllHosts_v6_Eth); } } // Pass 2: For all types of NDP packet we check the Sender IP address to make sure it doesn't conflict with any AddressProxy record we're holding. if (mDNSSameEthAddress(sha, &intf->MAC)) debugf("NDP from self for %.16a", &ndp->target); else { // For Neighbor Advertisements we check the Target address field, not the actual IPv6 source address. // When a machine has both link-local and routable IPv6 addresses, it may send NDP packets making assertions // about its routable IPv6 address, using its link-local address as the source address for all NDP packets. // Hence it is the NDP target address we care about, not the actual packet source address. if (ndp->type == NDP_Adv) spa = &ndp->target; if (!mDNSSameIPv6Address(*spa, zerov6Addr)) for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->resrec.InterfaceID == InterfaceID && rr->resrec.RecordType != kDNSRecordTypeDeregistering && rr->AddressProxy.type == mDNSAddrType_IPv6 && mDNSSameIPv6Address(rr->AddressProxy.ip.v6, *spa) && (rr->ProbeRestartCount < MAX_PROBE_RESTARTS)) { if (mDNSSameEthAddress(&zeroEthAddr, &rr->WakeUp.HMAC)) { LogSPS("%-7s NDP from %.6a %.16a for %.16a -- Invalid H-MAC %.6a I-MAC %.6a %s", intf->ifname, sha, spa, &ndp->target, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, ARDisplayString(m, rr)); } else { RestartARPProbing(m, rr); if (mDNSSameEthAddress(sha, &rr->WakeUp.IMAC)) { LogSPS("%-7s NDP %s from owner %.6a %.16a for %.16a -- re-starting probing for %s", intf->ifname, ndp->type == NDP_Sol ? "Solicitation " : "Advertisement", sha, spa, &ndp->target, ARDisplayString(m, rr)); } else { LogMsg("%-7s Conflicting NDP from %.6a %.16a for %.16a -- waking H-MAC %.6a I-MAC %.6a %s", intf->ifname, sha, spa, &ndp->target, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, ARDisplayString(m, rr)); ScheduleWakeup(m, rr->resrec.InterfaceID, &rr->WakeUp.HMAC); } } } } mDNS_Unlock(m); } mDNSlocal void mDNSCoreReceiveRawTransportPacket(mDNS *const m, const mDNSEthAddr *const sha, const mDNSAddr *const src, const mDNSAddr *const dst, const mDNSu8 protocol, const mDNSu8 *const p, const TransportLayerPacket *const t, const mDNSu8 *const end, const mDNSInterfaceID InterfaceID, const mDNSu16 len) { const mDNSIPPort port = (protocol == 0x06) ? t->tcp.dst : (protocol == 0x11) ? t->udp.dst : zeroIPPort; mDNSBool wake = mDNSfalse; mDNSBool kaWake = mDNSfalse; switch (protocol) { #define XX wake ? "Received" : "Ignoring", end-p case 0x01: LogSPS("Ignoring %d-byte ICMP from %#a to %#a", end-p, src, dst); break; case 0x06: { AuthRecord *kr; mDNSu32 seq, ack; #define TH_FIN 0x01 #define TH_SYN 0x02 #define TH_RST 0x04 #define TH_ACK 0x10 kr = mDNS_MatchKeepaliveInfo(m, dst, src, port, t->tcp.src, &seq, &ack); if (kr) { LogSPS("mDNSCoreReceiveRawTransportPacket: Found a Keepalive record from %#a:%d to %#a:%d", src, mDNSVal16(t->tcp.src), dst, mDNSVal16(port)); // Plan to wake if // (a) RST or FIN is set (the keepalive that we sent could have caused a reset) // (b) packet that contains new data and acks a sequence number higher than the one // we have been sending in the keepalive wake = ((t->tcp.flags & TH_RST) || (t->tcp.flags & TH_FIN)) ; if (!wake) { mDNSu8 *ptr; mDNSu32 pseq, pack; mDNSBool data = mDNSfalse; mDNSu8 tcphlen; // Convert to host order ptr = (mDNSu8 *)&seq; seq = ptr[0] << 24 | ptr[1] << 16 | ptr[2] << 8 | ptr[3]; ptr = (mDNSu8 *)&ack; ack = ptr[0] << 24 | ptr[1] << 16 | ptr[2] << 8 | ptr[3]; pseq = t->tcp.seq; ptr = (mDNSu8 *)&pseq; pseq = ptr[0] << 24 | ptr[1] << 16 | ptr[2] << 8 | ptr[3]; pack = t->tcp.ack; ptr = (mDNSu8 *)&pack; pack = ptr[0] << 24 | ptr[1] << 16 | ptr[2] << 8 | ptr[3]; // If the other side is acking one more than our sequence number (keepalive is one // less than the last valid sequence sent) and it's sequence is more than what we // acked before //if (end - p - 34 - ((t->tcp.offset >> 4) * 4) > 0) data = mDNStrue; tcphlen = ((t->tcp.offset >> 4) * 4); if (end - ((mDNSu8 *)t + tcphlen) > 0) data = mDNStrue; wake = ((int)(pack - seq) > 0) && ((int)(pseq - ack) >= 0) && data; // If we got a regular keepalive on a connection that was registed with the KeepAlive API, respond with an ACK if ((t->tcp.flags & TH_ACK) && (data == mDNSfalse) && ((int)(ack - pseq) == 1)) { // Send an ACK; mDNS_SendKeepaliveACK(m, kr); } LogSPS("mDNSCoreReceiveRawTransportPacket: End %p, hlen %d, Datalen %d, pack %u, seq %u, pseq %u, ack %u, wake %d", end, tcphlen, end - ((mDNSu8 *)t + tcphlen), pack, seq, pseq, ack, wake); } else { LogSPS("mDNSCoreReceiveRawTransportPacket: waking because of RST or FIN th_flags %d", t->tcp.flags); } kaWake = wake; } else { // Plan to wake if // (a) RST is not set, AND // (b) packet is SYN, SYN+FIN, or plain data packet (no SYN or FIN). We won't wake for FIN alone. wake = (!(t->tcp.flags & TH_RST) && (t->tcp.flags & (TH_FIN|TH_SYN)) != TH_FIN); // For now, to reduce spurious wakeups, we wake only for TCP SYN, // except for ssh connections, where we'll wake for plain data packets too if (!mDNSSameIPPort(port, SSHPort) && !(t->tcp.flags & 2)) wake = mDNSfalse; LogSPS("%s %d-byte TCP from %#a:%d to %#a:%d%s%s%s", XX, src, mDNSVal16(t->tcp.src), dst, mDNSVal16(port), (t->tcp.flags & 2) ? " SYN" : "", (t->tcp.flags & 1) ? " FIN" : "", (t->tcp.flags & 4) ? " RST" : ""); } break; } case 0x11: { #define ARD_AsNumber 3283 static const mDNSIPPort ARD = { { ARD_AsNumber >> 8, ARD_AsNumber & 0xFF } }; const mDNSu16 udplen = (mDNSu16)((mDNSu16)t->bytes[4] << 8 | t->bytes[5]); // Length *including* 8-byte UDP header if (udplen >= sizeof(UDPHeader)) { const mDNSu16 datalen = udplen - sizeof(UDPHeader); wake = mDNStrue; // For Back to My Mac UDP port 4500 (IPSEC) packets, we do some special handling if (mDNSSameIPPort(port, IPSECPort)) { // Specifically ignore NAT keepalive packets if (datalen == 1 && end >= &t->bytes[9] && t->bytes[8] == 0xFF) wake = mDNSfalse; else { // Skip over the Non-ESP Marker if present const mDNSBool NonESP = (end >= &t->bytes[12] && t->bytes[8] == 0 && t->bytes[9] == 0 && t->bytes[10] == 0 && t->bytes[11] == 0); const IKEHeader *const ike = (IKEHeader *)(t + (NonESP ? 12 : 8)); const mDNSu16 ikelen = datalen - (NonESP ? 4 : 0); if (ikelen >= sizeof(IKEHeader) && end >= ((mDNSu8 *)ike) + sizeof(IKEHeader)) if ((ike->Version & 0x10) == 0x10) { // ExchangeType == 5 means 'Informational' // ExchangeType == 34 means 'IKE_SA_INIT' if (ike->ExchangeType == 5 || ike->ExchangeType == 34) wake = mDNSfalse; LogSPS("%s %d-byte IKE ExchangeType %d", XX, ike->ExchangeType); } } } // For now, because we haven't yet worked out a clean elegant way to do this, we just special-case the // Apple Remote Desktop port number -- we ignore all packets to UDP 3283 (the "Net Assistant" port), // except for Apple Remote Desktop's explicit manual wakeup packet, which looks like this: // UDP header (8 bytes) // Payload: 13 88 00 6a 41 4e 41 20 (8 bytes) ffffffffffff (6 bytes) 16xMAC (96 bytes) = 110 bytes total if (mDNSSameIPPort(port, ARD)) wake = (datalen >= 110 && end >= &t->bytes[10] && t->bytes[8] == 0x13 && t->bytes[9] == 0x88); LogSPS("%s %d-byte UDP from %#a:%d to %#a:%d", XX, src, mDNSVal16(t->udp.src), dst, mDNSVal16(port)); } } break; case 0x3A: if (&t->bytes[len] <= end) { mDNSu16 checksum = IPv6CheckSum(&src->ip.v6, &dst->ip.v6, protocol, t->bytes, len); if (!checksum) mDNSCoreReceiveRawND(m, sha, &src->ip.v6, &t->ndp, &t->bytes[len], InterfaceID); else LogInfo("IPv6CheckSum bad %04X %02X%02X from %#a to %#a", checksum, t->bytes[2], t->bytes[3], src, dst); } break; default: LogSPS("Ignoring %d-byte IP packet unknown protocol %d from %#a to %#a", end-p, protocol, src, dst); break; } if (wake) { AuthRecord *rr, *r2; mDNS_Lock(m); for (rr = m->ResourceRecords; rr; rr=rr->next) if (rr->resrec.InterfaceID == InterfaceID && rr->resrec.RecordType != kDNSRecordTypeDeregistering && rr->AddressProxy.type && mDNSSameAddress(&rr->AddressProxy, dst)) { const mDNSu8 *const tp = (protocol == 6) ? (const mDNSu8 *)"\x4_tcp" : (const mDNSu8 *)"\x4_udp"; for (r2 = m->ResourceRecords; r2; r2=r2->next) if (r2->resrec.InterfaceID == InterfaceID && mDNSSameEthAddress(&r2->WakeUp.HMAC, &rr->WakeUp.HMAC) && r2->resrec.RecordType != kDNSRecordTypeDeregistering && r2->resrec.rrtype == kDNSType_SRV && mDNSSameIPPort(r2->resrec.rdata->u.srv.port, port) && SameDomainLabel(ThirdLabel(r2->resrec.name)->c, tp)) break; if (!r2 && mDNSSameIPPort(port, IPSECPort)) r2 = rr; // So that we wake for BTMM IPSEC packets, even without a matching SRV record if (!r2 && kaWake) r2 = rr; // So that we wake for keepalive packets, even without a matching SRV record if (r2) { LogMsg("Waking host at %s %#a H-MAC %.6a I-MAC %.6a for %s", InterfaceNameForID(m, rr->resrec.InterfaceID), dst, &rr->WakeUp.HMAC, &rr->WakeUp.IMAC, ARDisplayString(m, r2)); ScheduleWakeup(m, rr->resrec.InterfaceID, &rr->WakeUp.HMAC); } else LogSPS("Sleeping host at %s %#a %.6a has no service on %#s %d", InterfaceNameForID(m, rr->resrec.InterfaceID), dst, &rr->WakeUp.HMAC, tp, mDNSVal16(port)); } mDNS_Unlock(m); } } mDNSexport void mDNSCoreReceiveRawPacket(mDNS *const m, const mDNSu8 *const p, const mDNSu8 *const end, const mDNSInterfaceID InterfaceID) { static const mDNSOpaque16 Ethertype_ARP = { { 0x08, 0x06 } }; // Ethertype 0x0806 = ARP static const mDNSOpaque16 Ethertype_IPv4 = { { 0x08, 0x00 } }; // Ethertype 0x0800 = IPv4 static const mDNSOpaque16 Ethertype_IPv6 = { { 0x86, 0xDD } }; // Ethertype 0x86DD = IPv6 static const mDNSOpaque16 ARP_hrd_eth = { { 0x00, 0x01 } }; // Hardware address space (Ethernet = 1) static const mDNSOpaque16 ARP_pro_ip = { { 0x08, 0x00 } }; // Protocol address space (IP = 0x0800) // Note: BPF guarantees that the NETWORK LAYER header will be word aligned, not the link-layer header. // In other words, we can safely assume that pkt below (ARP, IPv4 or IPv6) is properly word aligned, // but if pkt is 4-byte aligned, that necessarily means that eth CANNOT also be 4-byte aligned // since it points to a an address 14 bytes before pkt. const EthernetHeader *const eth = (const EthernetHeader *)p; const NetworkLayerPacket *const pkt = (const NetworkLayerPacket *)(eth+1); mDNSAddr src, dst; #define RequiredCapLen(P) ((P)==0x01 ? 4 : (P)==0x06 ? 20 : (P)==0x11 ? 8 : (P)==0x3A ? 24 : 0) // Is ARP? Length must be at least 14 + 28 = 42 bytes if (end >= p+42 && mDNSSameOpaque16(eth->ethertype, Ethertype_ARP) && mDNSSameOpaque16(pkt->arp.hrd, ARP_hrd_eth) && mDNSSameOpaque16(pkt->arp.pro, ARP_pro_ip)) mDNSCoreReceiveRawARP(m, &pkt->arp, InterfaceID); // Is IPv4 with zero fragmentation offset? Length must be at least 14 + 20 = 34 bytes else if (end >= p+34 && mDNSSameOpaque16(eth->ethertype, Ethertype_IPv4) && (pkt->v4.flagsfrags.b[0] & 0x1F) == 0 && pkt->v4.flagsfrags.b[1] == 0) { const mDNSu8 *const trans = p + 14 + (pkt->v4.vlen & 0xF) * 4; const mDNSu8 * transEnd = p + 14 + mDNSVal16(pkt->v4.totlen); if (transEnd > end) transEnd = end; debugf("Got IPv4 %02X from %.4a to %.4a", pkt->v4.protocol, &pkt->v4.src, &pkt->v4.dst); src.type = mDNSAddrType_IPv4; src.ip.v4 = pkt->v4.src; dst.type = mDNSAddrType_IPv4; dst.ip.v4 = pkt->v4.dst; if (transEnd >= trans + RequiredCapLen(pkt->v4.protocol)) mDNSCoreReceiveRawTransportPacket(m, ð->src, &src, &dst, pkt->v4.protocol, p, (TransportLayerPacket*)trans, transEnd, InterfaceID, 0); } // Is IPv6? Length must be at least 14 + 28 = 42 bytes else if (end >= p+54 && mDNSSameOpaque16(eth->ethertype, Ethertype_IPv6)) { const mDNSu8 *const trans = p + 54; debugf("Got IPv6 %02X from %.16a to %.16a", pkt->v6.pro, &pkt->v6.src, &pkt->v6.dst); src.type = mDNSAddrType_IPv6; src.ip.v6 = pkt->v6.src; dst.type = mDNSAddrType_IPv6; dst.ip.v6 = pkt->v6.dst; if (end >= trans + RequiredCapLen(pkt->v6.pro)) mDNSCoreReceiveRawTransportPacket(m, ð->src, &src, &dst, pkt->v6.pro, p, (TransportLayerPacket*)trans, end, InterfaceID, (mDNSu16)pkt->bytes[4] << 8 | pkt->bytes[5]); } } mDNSlocal void ConstructSleepProxyServerName(mDNS *const m, domainlabel *name) { name->c[0] = (mDNSu8)mDNS_snprintf((char*)name->c+1, 62, "%d-%d-%d-%d.%d %#s", m->SPSType, m->SPSPortability, m->SPSMarginalPower, m->SPSTotalPower, m->SPSFeatureFlags, &m->nicelabel); } #ifndef SPC_DISABLED mDNSlocal void SleepProxyServerCallback(mDNS *const m, ServiceRecordSet *const srs, mStatus result) { if (result == mStatus_NameConflict) mDNS_RenameAndReregisterService(m, srs, mDNSNULL); else if (result == mStatus_MemFree) { if (m->SleepState) m->SPSState = 3; else { m->SPSState = (mDNSu8)(m->SPSSocket != mDNSNULL); if (m->SPSState) { domainlabel name; ConstructSleepProxyServerName(m, &name); mDNS_RegisterService(m, srs, &name, &SleepProxyServiceType, &localdomain, mDNSNULL, m->SPSSocket->port, // Host, port (mDNSu8 *)"", 1, // TXT data, length mDNSNULL, 0, // Subtypes (none) mDNSInterface_Any, // Interface ID SleepProxyServerCallback, mDNSNULL, 0); // Callback, context, flags } LogSPS("Sleep Proxy Server %#s %s", srs->RR_SRV.resrec.name->c, m->SPSState ? "started" : "stopped"); } } } #endif // Called with lock held mDNSexport void mDNSCoreBeSleepProxyServer_internal(mDNS *const m, mDNSu8 sps, mDNSu8 port, mDNSu8 marginalpower, mDNSu8 totpower, mDNSu8 features) { // This routine uses mDNS_DeregisterService and calls SleepProxyServerCallback, so we execute in user callback context mDNS_DropLockBeforeCallback(); // If turning off SPS, close our socket // (Do this first, BEFORE calling mDNS_DeregisterService below) if (!sps && m->SPSSocket) { mDNSPlatformUDPClose(m->SPSSocket); m->SPSSocket = mDNSNULL; } // If turning off, or changing type, deregister old name #ifndef SPC_DISABLED if (m->SPSState == 1 && sps != m->SPSType) { m->SPSState = 2; mDNS_DeregisterService_drt(m, &m->SPSRecords, sps ? mDNS_Dereg_rapid : mDNS_Dereg_normal); } #endif // SPC_DISABLED // Record our new SPS parameters m->SPSType = sps; m->SPSPortability = port; m->SPSMarginalPower = marginalpower; m->SPSTotalPower = totpower; m->SPSFeatureFlags = features; // If turning on, open socket and advertise service if (sps) { if (!m->SPSSocket) { m->SPSSocket = mDNSPlatformUDPSocket(zeroIPPort); if (!m->SPSSocket) { LogMsg("mDNSCoreBeSleepProxyServer: Failed to allocate SPSSocket"); goto fail; } } #ifndef SPC_DISABLED if (m->SPSState == 0) SleepProxyServerCallback(m, &m->SPSRecords, mStatus_MemFree); #endif // SPC_DISABLED } else if (m->SPSState) { LogSPS("mDNSCoreBeSleepProxyServer turning off from state %d; will wake clients", m->SPSState); m->NextScheduledSPS = m->timenow; } fail: mDNS_ReclaimLockAfterCallback(); } // *************************************************************************** #if COMPILER_LIKES_PRAGMA_MARK #pragma mark - #pragma mark - Startup and Shutdown #endif mDNSlocal void mDNS_GrowCache_internal(mDNS *const m, CacheEntity *storage, mDNSu32 numrecords) { if (storage && numrecords) { mDNSu32 i; debugf("Adding cache storage for %d more records (%d bytes)", numrecords, numrecords*sizeof(CacheEntity)); for (i=0; irrcache_free; m->rrcache_free = storage; m->rrcache_size += numrecords; } } mDNSexport void mDNS_GrowCache(mDNS *const m, CacheEntity *storage, mDNSu32 numrecords) { mDNS_Lock(m); mDNS_GrowCache_internal(m, storage, numrecords); mDNS_Unlock(m); } mDNSlocal mStatus mDNS_InitStorage(mDNS *const m, mDNS_PlatformSupport *const p, CacheEntity *rrcachestorage, mDNSu32 rrcachesize, mDNSBool AdvertiseLocalAddresses, mDNSCallback *Callback, void *Context) { mDNSu32 slot; mDNSs32 timenow; mStatus result; if (!rrcachestorage) rrcachesize = 0; m->p = p; m->NetworkChanged = 0; m->CanReceiveUnicastOn5353 = mDNSfalse; // Assume we can't receive unicasts on 5353, unless platform layer tells us otherwise m->AdvertiseLocalAddresses = AdvertiseLocalAddresses; m->DivertMulticastAdvertisements = mDNSfalse; m->mDNSPlatformStatus = mStatus_Waiting; m->UnicastPort4 = zeroIPPort; m->UnicastPort6 = zeroIPPort; m->PrimaryMAC = zeroEthAddr; m->MainCallback = Callback; m->MainContext = Context; m->rec.r.resrec.RecordType = 0; m->rec.r.resrec.AnonInfo = mDNSNULL; // For debugging: To catch and report locking failures m->mDNS_busy = 0; m->mDNS_reentrancy = 0; m->ShutdownTime = 0; m->lock_rrcache = 0; m->lock_Questions = 0; m->lock_Records = 0; // Task Scheduling variables result = mDNSPlatformTimeInit(); if (result != mStatus_NoError) return(result); m->timenow_adjust = (mDNSs32)mDNSRandom(0xFFFFFFFF); timenow = mDNS_TimeNow_NoLock(m); m->timenow = 0; // MUST only be set within mDNS_Lock/mDNS_Unlock section m->timenow_last = timenow; m->NextScheduledEvent = timenow; m->SuppressSending = timenow; m->NextCacheCheck = timenow + FutureTime; m->NextScheduledQuery = timenow + FutureTime; m->NextScheduledProbe = timenow + FutureTime; m->NextScheduledResponse = timenow + FutureTime; m->NextScheduledNATOp = timenow + FutureTime; m->NextScheduledSPS = timenow + FutureTime; m->NextScheduledKA = timenow + FutureTime; m->NextScheduledStopTime = timenow + FutureTime; m->NextBLEServiceTime = 0; // zero indicates inactive #if BONJOUR_ON_DEMAND m->NextBonjourDisableTime = 0; // Timer active when non zero. m->BonjourEnabled = 0; // Set when Bonjour on Demand is enabled and Bonjour is currently enabled. #endif // BONJOUR_ON_DEMAND m->DelayConflictProcessing = MAX_CONFLICT_PROCESSING_DELAYS; m->RandomQueryDelay = 0; m->RandomReconfirmDelay = 0; m->PktNum = 0; m->MPktNum = 0; m->LocalRemoveEvents = mDNSfalse; m->SleepState = SleepState_Awake; m->SleepSeqNum = 0; m->SystemWakeOnLANEnabled = mDNSfalse; m->AnnounceOwner = NonZeroTime(timenow + 60 * mDNSPlatformOneSecond); m->DelaySleep = 0; m->SleepLimit = 0; #if APPLE_OSX_mDNSResponder m->UnicastPacketsSent = 0; m->MulticastPacketsSent = 0; m->RemoteSubnet = 0; #endif // APPLE_OSX_mDNSResponder // These fields only required for mDNS Searcher... m->Questions = mDNSNULL; m->NewQuestions = mDNSNULL; m->CurrentQuestion = mDNSNULL; m->LocalOnlyQuestions = mDNSNULL; m->NewLocalOnlyQuestions = mDNSNULL; m->RestartQuestion = mDNSNULL; m->ValidationQuestion = mDNSNULL; m->rrcache_size = 0; m->rrcache_totalused = 0; m->rrcache_active = 0; m->rrcache_report = 10; m->rrcache_free = mDNSNULL; for (slot = 0; slot < CACHE_HASH_SLOTS; slot++) { m->rrcache_hash[slot] = mDNSNULL; m->rrcache_nextcheck[slot] = timenow + FutureTime;; } mDNS_GrowCache_internal(m, rrcachestorage, rrcachesize); m->rrauth.rrauth_free = mDNSNULL; for (slot = 0; slot < AUTH_HASH_SLOTS; slot++) m->rrauth.rrauth_hash[slot] = mDNSNULL; // Fields below only required for mDNS Responder... m->hostlabel.c[0] = 0; m->nicelabel.c[0] = 0; m->MulticastHostname.c[0] = 0; m->HIHardware.c[0] = 0; m->HISoftware.c[0] = 0; m->ResourceRecords = mDNSNULL; m->DuplicateRecords = mDNSNULL; m->NewLocalRecords = mDNSNULL; m->NewLocalOnlyRecords = mDNSfalse; m->CurrentRecord = mDNSNULL; m->HostInterfaces = mDNSNULL; m->ProbeFailTime = 0; m->NumFailedProbes = 0; m->SuppressProbes = 0; #ifndef UNICAST_DISABLED m->NextuDNSEvent = timenow + FutureTime; m->NextSRVUpdate = timenow + FutureTime; m->DNSServers = mDNSNULL; m->Router = zeroAddr; m->AdvertisedV4 = zeroAddr; m->AdvertisedV6 = zeroAddr; m->AuthInfoList = mDNSNULL; m->ReverseMap.ThisQInterval = -1; m->StaticHostname.c[0] = 0; m->FQDN.c[0] = 0; m->Hostnames = mDNSNULL; m->AutoTunnelNAT.clientContext = mDNSNULL; m->WABBrowseQueriesCount = 0; m->WABLBrowseQueriesCount = 0; m->WABRegQueriesCount = 0; m->AutoTargetServices = 1; #if BONJOUR_ON_DEMAND m->NumAllInterfaceRecords = 0; m->NumAllInterfaceQuestions = 0; #endif // NAT traversal fields m->LLQNAT.clientCallback = mDNSNULL; m->LLQNAT.clientContext = mDNSNULL; m->NATTraversals = mDNSNULL; m->CurrentNATTraversal = mDNSNULL; m->retryIntervalGetAddr = 0; // delta between time sent and retry m->retryGetAddr = timenow + FutureTime; // absolute time when we retry m->ExtAddress = zerov4Addr; m->PCPNonce[0] = mDNSRandom(-1); m->PCPNonce[1] = mDNSRandom(-1); m->PCPNonce[2] = mDNSRandom(-1); m->NATMcastRecvskt = mDNSNULL; m->LastNATupseconds = 0; m->LastNATReplyLocalTime = timenow; m->LastNATMapResultCode = NATErr_None; m->UPnPInterfaceID = 0; m->SSDPSocket = mDNSNULL; m->SSDPWANPPPConnection = mDNSfalse; m->UPnPRouterPort = zeroIPPort; m->UPnPSOAPPort = zeroIPPort; m->UPnPRouterURL = mDNSNULL; m->UPnPWANPPPConnection = mDNSfalse; m->UPnPSOAPURL = mDNSNULL; m->UPnPRouterAddressString = mDNSNULL; m->UPnPSOAPAddressString = mDNSNULL; m->SPSType = 0; m->SPSPortability = 0; m->SPSMarginalPower = 0; m->SPSTotalPower = 0; m->SPSFeatureFlags = 0; m->SPSState = 0; m->SPSProxyListChanged = mDNSNULL; m->SPSSocket = mDNSNULL; m->SPSBrowseCallback = mDNSNULL; m->ProxyRecords = 0; m->DNSPushServers = mDNSNULL; m->DNSPushZones = mDNSNULL; #endif #if APPLE_OSX_mDNSResponder m->TunnelClients = mDNSNULL; #if !NO_WCF CHECK_WCF_FUNCTION(WCFConnectionNew) { m->WCF = WCFConnectionNew(); if (!m->WCF) { LogMsg("WCFConnectionNew failed"); return -1; } } #endif #endif return(result); } mDNSexport mStatus mDNS_Init(mDNS *const m, mDNS_PlatformSupport *const p, CacheEntity *rrcachestorage, mDNSu32 rrcachesize, mDNSBool AdvertiseLocalAddresses, mDNSCallback *Callback, void *Context) { mStatus result = mDNS_InitStorage(m, p, rrcachestorage, rrcachesize, AdvertiseLocalAddresses, Callback, Context); if (result != mStatus_NoError) return(result); result = mDNSPlatformInit(m); #ifndef UNICAST_DISABLED // It's better to do this *after* the platform layer has set up the // interface list and security credentials uDNS_SetupDNSConfig(m); // Get initial DNS configuration #endif return(result); } mDNSexport void mDNS_ConfigChanged(mDNS *const m) { if (m->SPSState == 1) { domainlabel name, newname; #ifndef SPC_DISABLED domainname type, domain; DeconstructServiceName(m->SPSRecords.RR_SRV.resrec.name, &name, &type, &domain); #endif // SPC_DISABLED ConstructSleepProxyServerName(m, &newname); if (!SameDomainLabelCS(name.c, newname.c)) { LogSPS("Renaming SPS from “%#s” to “%#s”", name.c, newname.c); // When SleepProxyServerCallback gets the mStatus_MemFree message, // it will reregister the service under the new name m->SPSState = 2; #ifndef SPC_DISABLED mDNS_DeregisterService_drt(m, &m->SPSRecords, mDNS_Dereg_rapid); #endif // SPC_DISABLED } } if (m->MainCallback) m->MainCallback(m, mStatus_ConfigChanged); } mDNSlocal void DynDNSHostNameCallback(mDNS *const m, AuthRecord *const rr, mStatus result) { (void)m; // unused debugf("NameStatusCallback: result %d for registration of name %##s", result, rr->resrec.name->c); mDNSPlatformDynDNSHostNameStatusChanged(rr->resrec.name, result); } mDNSlocal void PurgeOrReconfirmCacheRecord(mDNS *const m, CacheRecord *cr, const DNSServer * const ptr, mDNSBool lameduck) { mDNSBool purge = cr->resrec.RecordType == kDNSRecordTypePacketNegative || cr->resrec.rrtype == kDNSType_A || cr->resrec.rrtype == kDNSType_AAAA || cr->resrec.rrtype == kDNSType_SRV || cr->resrec.rrtype == kDNSType_CNAME; (void) lameduck; (void) ptr; debugf("PurgeOrReconfirmCacheRecord: %s cache record due to %s server %p %#a:%d (%##s): %s", purge ? "purging" : "reconfirming", lameduck ? "lame duck" : "new", ptr, &ptr->addr, mDNSVal16(ptr->port), ptr->domain.c, CRDisplayString(m, cr)); if (purge) { LogInfo("PurgeorReconfirmCacheRecord: Purging Resourcerecord %s, RecordType %x", CRDisplayString(m, cr), cr->resrec.RecordType); mDNS_PurgeCacheResourceRecord(m, cr); } else { LogInfo("PurgeorReconfirmCacheRecord: Reconfirming Resourcerecord %s, RecordType %x", CRDisplayString(m, cr), cr->resrec.RecordType); mDNS_Reconfirm_internal(m, cr, kDefaultReconfirmTimeForNoAnswer); } } mDNSlocal void mDNS_PurgeForQuestion(mDNS *const m, DNSQuestion *q) { CacheGroup *const cg = CacheGroupForName(m, q->qnamehash, &q->qname); CacheRecord *rp; mDNSu8 validatingResponse = 0; // For DNSSEC questions, purge the corresponding RRSIGs also. if (DNSSECQuestion(q)) { validatingResponse = q->ValidatingResponse; q->ValidatingResponse = mDNStrue; } for (rp = cg ? cg->members : mDNSNULL; rp; rp = rp->next) { if (SameNameRecordAnswersQuestion(&rp->resrec, q)) { LogInfo("mDNS_PurgeForQuestion: Flushing %s", CRDisplayString(m, rp)); mDNS_PurgeCacheResourceRecord(m, rp); } } if (DNSSECQuestion(q)) { q->ValidatingResponse = validatingResponse; } } // For DNSSEC question, we need the DNSSEC records also. If the cache does not // have the DNSSEC records, we need to re-issue the question with EDNS0/DO bit set. // Just re-issuing the question for RRSIGs does not work in practice as the response // may not contain the RRSIGs whose typeCovered field matches the question's qtype. // // For negative responses, we need the NSECs to prove the non-existence. If we don't // have the cached NSECs, purge them. For positive responses, if we don't have the // RRSIGs and if we have not already issued the question with EDNS0/DO bit set, purge // them. mDNSlocal void CheckForDNSSECRecords(mDNS *const m, DNSQuestion *q) { CacheGroup *const cg = CacheGroupForName(m, q->qnamehash, &q->qname); CacheRecord *rp; for (rp = cg ? cg->members : mDNSNULL; rp; rp = rp->next) { if (SameNameRecordAnswersQuestion(&rp->resrec, q)) { if (rp->resrec.RecordType != kDNSRecordTypePacketNegative || !rp->nsec) { if (!rp->CRDNSSECQuestion) { LogInfo("CheckForDNSSECRecords: Flushing %s", CRDisplayString(m, rp)); mDNS_PurgeCacheResourceRecord(m, rp); } } } } } // Check for a positive unicast response to the question but with qtype mDNSexport mDNSBool mDNS_CheckForCacheRecord(mDNS *const m, DNSQuestion *q, mDNSu16 qtype) { DNSQuestion question; CacheGroup *const cg = CacheGroupForName(m, q->qnamehash, &q->qname); CacheRecord *rp; // Create an identical question but with qtype mDNS_SetupQuestion(&question, q->InterfaceID, &q->qname, qtype, mDNSNULL, mDNSNULL); question.qDNSServer = q->qDNSServer; for (rp = cg ? cg->members : mDNSNULL; rp; rp = rp->next) { if (!rp->resrec.InterfaceID && rp->resrec.RecordType != kDNSRecordTypePacketNegative && SameNameRecordAnswersQuestion(&rp->resrec, &question)) { LogInfo("mDNS_CheckForCacheRecord: Found %s", CRDisplayString(m, rp)); return mDNStrue; } } return mDNSfalse; } mDNSexport void DNSServerChangeForQuestion(mDNS *const m, DNSQuestion *q, DNSServer *new) { DNSQuestion *qptr; (void) m; if (q->DuplicateOf) LogMsg("DNSServerChangeForQuestion: ERROR: Called for duplicate question %##s", q->qname.c); // Make sure all the duplicate questions point to the same DNSServer so that delivery // of events for all of them are consistent. Duplicates for a question are always inserted // after in the list. q->qDNSServer = new; for (qptr = q->next ; qptr; qptr = qptr->next) { if (qptr->DuplicateOf == q) { qptr->validDNSServers = q->validDNSServers; qptr->qDNSServer = new; } } } mDNSlocal void SetConfigState(mDNS *const m, mDNSBool delete) { McastResolver *mr; DNSServer *ptr; if (delete) { for (ptr = m->DNSServers; ptr; ptr = ptr->next) { ptr->penaltyTime = 0; NumUnicastDNSServers--; ptr->flags |= DNSServer_FlagDelete; #if APPLE_OSX_mDNSResponder if (ptr->flags & DNSServer_FlagUnreachable) NumUnreachableDNSServers--; #endif } // We handle the mcast resolvers here itself as mDNSPlatformSetDNSConfig looks at // mcast resolvers. Today we get both mcast and ucast configuration using the same // API for (mr = m->McastResolvers; mr; mr = mr->next) mr->flags |= McastResolver_FlagDelete; } else { for (ptr = m->DNSServers; ptr; ptr = ptr->next) { ptr->penaltyTime = 0; NumUnicastDNSServers++; ptr->flags &= ~DNSServer_FlagDelete; #if APPLE_OSX_mDNSResponder if (ptr->flags & DNSServer_FlagUnreachable) NumUnreachableDNSServers++; #endif } for (mr = m->McastResolvers; mr; mr = mr->next) mr->flags &= ~McastResolver_FlagDelete; } } mDNSlocal void SetDynDNSHostNameIfChanged(mDNS *const m, domainname *const fqdn) { // Did our FQDN change? if (!SameDomainName(fqdn, &m->FQDN)) { if (m->FQDN.c[0]) mDNS_RemoveDynDNSHostName(m, &m->FQDN); AssignDomainName(&m->FQDN, fqdn); if (m->FQDN.c[0]) { mDNSPlatformDynDNSHostNameStatusChanged(&m->FQDN, 1); mDNS_AddDynDNSHostName(m, &m->FQDN, DynDNSHostNameCallback, mDNSNULL); } } } mDNSexport mStatus uDNS_SetupDNSConfig(mDNS *const m) { mDNSu32 slot; CacheGroup *cg; CacheRecord *cr; mDNSBool Restart = mDNSfalse; mDNSAddr v4, v6, r; domainname fqdn; DNSServer *ptr, **p = &m->DNSServers; const DNSServer *oldServers = m->DNSServers; DNSQuestion *q; McastResolver *mr, **mres = &m->McastResolvers; debugf("uDNS_SetupDNSConfig: entry"); // Let the platform layer get the current DNS information and setup the WAB queries if needed. uDNS_SetupWABQueries(m); mDNS_Lock(m); // We need to first mark all the entries to be deleted. If the configuration changed, then // the entries would be undeleted appropriately. Otherwise, we need to clear them. // // Note: The last argument to mDNSPlatformSetDNSConfig is "mDNStrue" which means ack the // configuration. We already processed search domains in uDNS_SetupWABQueries above and // hence we are ready to ack the configuration as this is the last call to mDNSPlatformSetConfig // for the dns configuration change notification. SetConfigState(m, mDNStrue); if (!mDNSPlatformSetDNSConfig(mDNStrue, mDNSfalse, &fqdn, mDNSNULL, mDNSNULL, mDNStrue)) { SetDynDNSHostNameIfChanged(m, &fqdn); SetConfigState(m, mDNSfalse); mDNS_Unlock(m); LogInfo("uDNS_SetupDNSConfig: No configuration change"); return mStatus_NoError; } // For now, we just delete the mcast resolvers. We don't deal with cache or // questions here. Neither question nor cache point to mcast resolvers. Questions // do inherit the timeout values from mcast resolvers. But we don't bother // affecting them as they never change. while (*mres) { if (((*mres)->flags & McastResolver_FlagDelete) != 0) { mr = *mres; *mres = (*mres)->next; debugf("uDNS_SetupDNSConfig: Deleting mcast resolver %##s", mr, mr->domain.c); mDNSPlatformMemFree(mr); } else { (*mres)->flags &= ~McastResolver_FlagNew; mres = &(*mres)->next; } } // Update our qDNSServer pointers before we go and free the DNSServer object memory // // All non-scoped resolvers share the same resGroupID. At no point in time a cache entry using DNSServer // from scoped resolver will be used to answer non-scoped questions and vice versa, as scoped and non-scoped // resolvers don't share the same resGroupID. A few examples to describe the interaction with how we pick // DNSServers and flush the cache. // // - A non-scoped question picks DNSServer X, creates a cache entry with X. If a new resolver gets added later that // is a better match, we pick the new DNSServer for the question and activate the unicast query. We may or may not // flush the cache (See PurgeOrReconfirmCacheRecord). In either case, we don't change the cache record's DNSServer // pointer immediately (qDNSServer and rDNSServer may be different but still share the same resGroupID). If we don't // flush the cache immediately, the record's rDNSServer pointer will be updated (in mDNSCoreReceiveResponse) // later when we get the response. If we purge the cache, we still deliver a RMV when it is purged even though // we don't update the cache record's DNSServer pointer to match the question's DNSSever, as they both point to // the same resGroupID. // // Note: If the new DNSServer comes back with a different response than what we have in the cache, we will deliver a RMV // of the old followed by ADD of the new records. // // - A non-scoped question picks DNSServer X, creates a cache entry with X. If the resolver gets removed later, we will // pick a new DNSServer for the question which may or may not be NULL and set the cache record's pointer to the same // as in question's qDNSServer if the cache record is not flushed. If there is no active question, it will be set to NULL. // // - Two questions scoped and non-scoped for the same name will pick two different DNSServer and will end up creating separate // cache records and as the resGroupID is different, you can't use the cache record from the scoped DNSServer to answer the // non-scoped question and vice versa. // #if USE_DNS64 DNS64RestartQuestions(m); #endif for (q = m->Questions; q; q=q->next) { if (!mDNSOpaque16IsZero(q->TargetQID)) { DNSServer *s, *t; DNSQuestion *qptr; if (q->DuplicateOf) continue; SetValidDNSServers(m, q); q->triedAllServersOnce = 0; s = GetServerForQuestion(m, q); t = q->qDNSServer; if (t != s) { mDNSBool old, new; // If DNS Server for this question has changed, reactivate it LogInfo("uDNS_SetupDNSConfig: Updating DNS Server from %#a:%d (%##s) to %#a:%d (%##s) for question %##s (%s) (scope:%p)", t ? &t->addr : mDNSNULL, mDNSVal16(t ? t->port : zeroIPPort), t ? t->domain.c : (mDNSu8*)"", s ? &s->addr : mDNSNULL, mDNSVal16(s ? s->port : zeroIPPort), s ? s->domain.c : (mDNSu8*)"", q->qname.c, DNSTypeName(q->qtype), q->InterfaceID); old = q->SuppressQuery; new = ShouldSuppressUnicastQuery(m, q, s); if (old != new) { // Changing the DNS server affected the SuppressQuery status. We need to // deliver RMVs for the previous ADDs (if any) before switching to the new // DNSServer. To keep it simple, we walk all the questions and mark them // to be restarted and then handle all of them at once. q->Restart = 1; q->SuppressQuery = new; for (qptr = q->next ; qptr; qptr = qptr->next) { if (qptr->DuplicateOf == q) qptr->Restart = 1; } Restart = mDNStrue; } else { DNSServerChangeForQuestion(m, q, s); q->unansweredQueries = 0; // If we had sent a query out to DNSServer "t" and we are changing to "s", we // need to ignore the responses coming back from "t" as the DNS configuration // has changed e.g., when a new interface is coming up and that becomes the primary // interface, we switch to the DNS servers configured for the primary interface. In // this case, we should not accept responses associated with the previous interface as // the "name" could resolve differently on this new primary interface. Hence, discard // in-flight responses. q->TargetQID = mDNS_NewMessageID(m); if (!QuerySuppressed(q)) { debugf("uDNS_SetupDNSConfig: Activating query %p %##s (%s)", q, q->qname.c, DNSTypeName(q->qtype)); ActivateUnicastQuery(m, q, mDNStrue); // ActivateUnicastQuery is called for duplicate questions also as it does something // special for AutoTunnel questions for (qptr = q->next ; qptr; qptr = qptr->next) { if (qptr->DuplicateOf == q) ActivateUnicastQuery(m, qptr, mDNStrue); } } } } else { debugf("uDNS_SetupDNSConfig: Not Updating DNS server question %p %##s (%s) DNS server %#a:%d %p %d", q, q->qname.c, DNSTypeName(q->qtype), t ? &t->addr : mDNSNULL, mDNSVal16(t ? t->port : zeroIPPort), q->DuplicateOf, q->SuppressUnusable); for (qptr = q->next ; qptr; qptr = qptr->next) if (qptr->DuplicateOf == q) { qptr->validDNSServers = q->validDNSServers; qptr->qDNSServer = q->qDNSServer; } } } } if (Restart) RestartUnicastQuestions(m); FORALL_CACHERECORDS(slot, cg, cr) { if (cr->resrec.InterfaceID) continue; // We already walked the questions and restarted/reactivated them if the dns server // change affected the question. That should take care of updating the cache. But // what if there is no active question at this point when the DNS server change // happened ? There could be old cache entries lying around and if we don't flush // them, a new question after the DNS server change could pick up these stale // entries and get a wrong answer. // // For cache entries that have active questions we might have skipped rescheduling // the questions if they were suppressed (see above). To keep it simple, we walk // all the cache entries to make sure that there are no stale entries. We use the // active question's InterfaceID/ServiceID for looking up the right DNS server. // Note that the unscoped value for ServiceID is -1. // // Note: If GetServerForName returns NULL, it could either mean that there are no // DNS servers or no matching DNS servers for this question. In either case, // the cache should get purged below when we process deleted DNS servers. ptr = GetServerForName(m, cr->resrec.name, (cr->CRActiveQuestion ? cr->CRActiveQuestion->InterfaceID : mDNSNULL), (cr->CRActiveQuestion ? cr->CRActiveQuestion->ServiceID : -1)); // Purge or Reconfirm if this cache entry would use the new DNS server if (ptr && (ptr != cr->resrec.rDNSServer)) { // As the DNSServers for this cache record is not the same anymore, we don't // want any new questions to pick this old value. If there is no active question, // we can't possibly re-confirm, so purge in that case. If it is a DNSSEC question, // purge the cache as the DNSSEC capabilities of the DNS server may have changed. if (cr->CRActiveQuestion == mDNSNULL || DNSSECQuestion(cr->CRActiveQuestion)) { LogInfo("uDNS_SetupDNSConfig: Purging Resourcerecord %s, New DNS server %#a , Old DNS server %#a", CRDisplayString(m, cr), &ptr->addr, (cr->resrec.rDNSServer != mDNSNULL ? &cr->resrec.rDNSServer->addr : mDNSNULL)); mDNS_PurgeCacheResourceRecord(m, cr); } else { LogInfo("uDNS_SetupDNSConfig: Purging/Reconfirming Resourcerecord %s, New DNS server %#a, Old DNS server %#a", CRDisplayString(m, cr), &ptr->addr, (cr->resrec.rDNSServer != mDNSNULL ? &cr->resrec.rDNSServer->addr : mDNSNULL)); PurgeOrReconfirmCacheRecord(m, cr, ptr, mDNSfalse); } } // If a cache record's DNSServer pointer is NULL, but its active question got a DNSServer in this DNS configuration // update, then use its DNSServer. This way, the active question and its duplicates don't miss out on RMV events. if (!cr->resrec.rDNSServer && cr->CRActiveQuestion && cr->CRActiveQuestion->qDNSServer) { cr->resrec.rDNSServer = cr->CRActiveQuestion->qDNSServer; LogInfo("uDNS_SetupDNSConfig: Using active question's DNS server %#a for cache record %s", &cr->resrec.rDNSServer->addr, CRDisplayString(m, cr)); } } while (*p) { if (((*p)->flags & DNSServer_FlagDelete) != 0) { // Scan our cache, looking for uDNS records that we would have queried this server for. // We reconfirm any records that match, because in this world of split DNS, firewalls, etc. // different DNS servers can give different answers to the same question. ptr = *p; FORALL_CACHERECORDS(slot, cg, cr) { if (cr->resrec.InterfaceID) continue; if (cr->resrec.rDNSServer == ptr) { // If we don't have an active question for this cache record, neither Purge can // generate RMV events nor Reconfirm can send queries out. Just set the DNSServer // pointer on the record NULL so that we don't point to freed memory (We might dereference // DNSServer pointers from resource record for logging purposes). // // If there is an active question, point to its DNSServer as long as it does not point to the // freed one. We already went through the questions above and made them point at either the // new server or NULL if there is no server. if (cr->CRActiveQuestion) { DNSQuestion *qptr = cr->CRActiveQuestion; if (qptr->qDNSServer == ptr) { LogMsg("uDNS_SetupDNSConfig: ERROR!! Cache Record %s Active question %##s (%s) (scope:%p) pointing to DNSServer Address %#a" " to be freed", CRDisplayString(m, cr), qptr->qname.c, DNSTypeName(qptr->qtype), qptr->InterfaceID, &ptr->addr); qptr->validDNSServers = zeroOpaque128; qptr->qDNSServer = mDNSNULL; cr->resrec.rDNSServer = mDNSNULL; } else { LogInfo("uDNS_SetupDNSConfig: Cache Record %s, Active question %##s (%s) (scope:%p), pointing to DNSServer %#a (to be deleted)," " resetting to question's DNSServer Address %#a", CRDisplayString(m, cr), qptr->qname.c, DNSTypeName(qptr->qtype), qptr->InterfaceID, &ptr->addr, (qptr->qDNSServer) ? &qptr->qDNSServer->addr : mDNSNULL); cr->resrec.rDNSServer = qptr->qDNSServer; } } else { LogInfo("uDNS_SetupDNSConfig: Cache Record %##s has no Active question, Record's DNSServer Address %#a, Server to be deleted %#a", cr->resrec.name, &cr->resrec.rDNSServer->addr, &ptr->addr); cr->resrec.rDNSServer = mDNSNULL; } PurgeOrReconfirmCacheRecord(m, cr, ptr, mDNStrue); } } *p = (*p)->next; LogInfo("uDNS_SetupDNSConfig: Deleting server %p %#a:%d (%##s) %d", ptr, &ptr->addr, mDNSVal16(ptr->port), ptr->domain.c, NumUnicastDNSServers); mDNSPlatformMemFree(ptr); } else { (*p)->flags &= ~DNSServer_FlagNew; p = &(*p)->next; } } // If we now have no DNS servers at all and we used to have some, then immediately purge all unicast cache records (including for LLQs). // This is important for giving prompt remove events when the user disconnects the Ethernet cable or turns off wireless. // Otherwise, stale data lingers for 5-10 seconds, which is not the user-experience people expect from Bonjour. // Similarly, if we now have some DNS servers and we used to have none, we want to purge any fake negative results we may have generated. if ((m->DNSServers != mDNSNULL) != (oldServers != mDNSNULL)) { int count = 0; FORALL_CACHERECORDS(slot, cg, cr) { if (!cr->resrec.InterfaceID) { mDNS_PurgeCacheResourceRecord(m, cr); count++; } } LogInfo("uDNS_SetupDNSConfig: %s available; purged %d unicast DNS records from cache", m->DNSServers ? "DNS server became" : "No DNS servers", count); // Force anything that needs to get zone data to get that information again RestartRecordGetZoneData(m); } SetDynDNSHostNameIfChanged(m, &fqdn); mDNS_Unlock(m); // handle router and primary interface changes v4 = v6 = r = zeroAddr; v4.type = r.type = mDNSAddrType_IPv4; if (mDNSPlatformGetPrimaryInterface(&v4, &v6, &r) == mStatus_NoError && !mDNSv4AddressIsLinkLocal(&v4.ip.v4)) { mDNS_SetPrimaryInterfaceInfo(m, !mDNSIPv4AddressIsZero(v4.ip.v4) ? &v4 : mDNSNULL, !mDNSIPv6AddressIsZero(v6.ip.v6) ? &v6 : mDNSNULL, !mDNSIPv4AddressIsZero(r.ip.v4) ? &r : mDNSNULL); } else { mDNS_SetPrimaryInterfaceInfo(m, mDNSNULL, mDNSNULL, mDNSNULL); if (m->FQDN.c[0]) mDNSPlatformDynDNSHostNameStatusChanged(&m->FQDN, 1); // Set status to 1 to indicate temporary failure } debugf("uDNS_SetupDNSConfig: number of unicast DNS servers %d", NumUnicastDNSServers); return mStatus_NoError; } mDNSexport void mDNSCoreInitComplete(mDNS *const m, mStatus result) { m->mDNSPlatformStatus = result; if (m->MainCallback) { mDNS_Lock(m); mDNS_DropLockBeforeCallback(); // Allow client to legally make mDNS API calls from the callback m->MainCallback(m, mStatus_NoError); mDNS_ReclaimLockAfterCallback(); // Decrement mDNS_reentrancy to block mDNS API calls again mDNS_Unlock(m); } } mDNSlocal void DeregLoop(mDNS *const m, AuthRecord *const start) { m->CurrentRecord = start; while (m->CurrentRecord) { AuthRecord *rr = m->CurrentRecord; LogInfo("DeregLoop: %s deregistration for %p %02X %s", (rr->resrec.RecordType != kDNSRecordTypeDeregistering) ? "Initiating " : "Accelerating", rr, rr->resrec.RecordType, ARDisplayString(m, rr)); if (rr->resrec.RecordType != kDNSRecordTypeDeregistering) mDNS_Deregister_internal(m, rr, mDNS_Dereg_rapid); else if (rr->AnnounceCount > 1) { rr->AnnounceCount = 1; rr->LastAPTime = m->timenow - rr->ThisAPInterval; } // Mustn't advance m->CurrentRecord until *after* mDNS_Deregister_internal, because // new records could have been added to the end of the list as a result of that call. if (m->CurrentRecord == rr) // If m->CurrentRecord was not advanced for us, do it now m->CurrentRecord = rr->next; } } mDNSexport void mDNS_StartExit(mDNS *const m) { AuthRecord *rr; mDNS_Lock(m); LogInfo("mDNS_StartExit"); m->ShutdownTime = NonZeroTime(m->timenow + mDNSPlatformOneSecond * 5); mDNSCoreBeSleepProxyServer_internal(m, 0, 0, 0, 0, 0); #if APPLE_OSX_mDNSResponder #if !NO_WCF CHECK_WCF_FUNCTION(WCFConnectionDealloc) { if (m->WCF) WCFConnectionDealloc((WCFConnection *)m->WCF); } #endif #endif #ifndef UNICAST_DISABLED { SearchListElem *s; SuspendLLQs(m); // Don't need to do SleepRecordRegistrations() here // because we deregister all records and services later in this routine while (m->Hostnames) mDNS_RemoveDynDNSHostName(m, &m->Hostnames->fqdn); // For each member of our SearchList, deregister any records it may have created, and cut them from the list. // Otherwise they'll be forcibly deregistered for us (without being cut them from the appropriate list) // and we may crash because the list still contains dangling pointers. for (s = SearchList; s; s = s->next) while (s->AuthRecs) { ARListElem *dereg = s->AuthRecs; s->AuthRecs = s->AuthRecs->next; mDNS_Deregister_internal(m, &dereg->ar, mDNS_Dereg_normal); // Memory will be freed in the FreeARElemCallback } } #endif DeadvertiseAllInterfaceRecords(m); // Shut down all our active NAT Traversals while (m->NATTraversals) { NATTraversalInfo *t = m->NATTraversals; mDNS_StopNATOperation_internal(m, t); // This will cut 't' from the list, thereby advancing m->NATTraversals in the process // After stopping the NAT Traversal, we zero out the fields. // This has particularly important implications for our AutoTunnel records -- // when we deregister our AutoTunnel records below, we don't want their mStatus_MemFree // handlers to just turn around and attempt to re-register those same records. // Clearing t->ExternalPort/t->RequestedPort will cause the mStatus_MemFree callback handlers // to not do this. t->ExternalAddress = zerov4Addr; t->NewAddress = zerov4Addr; t->ExternalPort = zeroIPPort; t->RequestedPort = zeroIPPort; t->Lifetime = 0; t->Result = mStatus_NoError; } // Make sure there are nothing but deregistering records remaining in the list if (m->CurrentRecord) LogMsg("mDNS_StartExit: ERROR m->CurrentRecord already set %s", ARDisplayString(m, m->CurrentRecord)); // We're in the process of shutting down, so queries, etc. are no longer available. // Consequently, determining certain information, e.g. the uDNS update server's IP // address, will not be possible. The records on the main list are more likely to // already contain such information, so we deregister the duplicate records first. LogInfo("mDNS_StartExit: Deregistering duplicate resource records"); DeregLoop(m, m->DuplicateRecords); LogInfo("mDNS_StartExit: Deregistering resource records"); DeregLoop(m, m->ResourceRecords); // If we scheduled a response to send goodbye packets, we set NextScheduledResponse to now. Normally when deregistering records, // we allow up to 100ms delay (to help improve record grouping) but when shutting down we don't want any such delay. if (m->NextScheduledResponse - m->timenow < mDNSPlatformOneSecond) { m->NextScheduledResponse = m->timenow; m->SuppressSending = 0; } if (m->ResourceRecords) LogInfo("mDNS_StartExit: Sending final record deregistrations"); else LogInfo("mDNS_StartExit: No deregistering records remain"); for (rr = m->DuplicateRecords; rr; rr = rr->next) LogMsg("mDNS_StartExit: Should not still have Duplicate Records remaining: %02X %s", rr->resrec.RecordType, ARDisplayString(m, rr)); // If any deregistering records remain, send their deregistration announcements before we exit if (m->mDNSPlatformStatus != mStatus_NoError) DiscardDeregistrations(m); mDNS_Unlock(m); LogInfo("mDNS_StartExit: done"); } mDNSexport void mDNS_FinalExit(mDNS *const m) { mDNSu32 rrcache_active = 0; mDNSu32 rrcache_totalused = m->rrcache_totalused; mDNSu32 slot; AuthRecord *rr; LogInfo("mDNS_FinalExit: mDNSPlatformClose"); mDNSPlatformClose(m); for (slot = 0; slot < CACHE_HASH_SLOTS; slot++) { while (m->rrcache_hash[slot]) { CacheGroup *cg = m->rrcache_hash[slot]; while (cg->members) { CacheRecord *cr = cg->members; cg->members = cg->members->next; if (cr->CRActiveQuestion) rrcache_active++; ReleaseCacheRecord(m, cr); } cg->rrcache_tail = &cg->members; ReleaseCacheGroup(m, &m->rrcache_hash[slot]); } } debugf("mDNS_FinalExit: RR Cache was using %ld records, %lu active", rrcache_totalused, rrcache_active); if (rrcache_active != m->rrcache_active) LogMsg("*** ERROR *** rrcache_totalused %lu; rrcache_active %lu != m->rrcache_active %lu", rrcache_totalused, rrcache_active, m->rrcache_active); for (rr = m->ResourceRecords; rr; rr = rr->next) LogMsg("mDNS_FinalExit failed to send goodbye for: %p %02X %s", rr, rr->resrec.RecordType, ARDisplayString(m, rr)); LogInfo("mDNS_FinalExit: done"); } #ifdef UNIT_TEST #include "../unittests/mdns_ut.c" #endif