1 /* -*- Mode: C; tab-width: 4 -*- 2 * 3 * Copyright (c) 2002-2003 Apple Computer, Inc. All rights reserved. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 #ifndef __DNSCOMMON_H_ 19 #define __DNSCOMMON_H_ 20 21 #include "mDNSEmbeddedAPI.h" 22 23 #ifdef __cplusplus 24 extern "C" { 25 #endif 26 27 //************************************************************************************************************* 28 // Macros 29 30 // Note: The C preprocessor stringify operator ('#') makes a string from its argument, without macro expansion 31 // e.g. If "version" is #define'd to be "4", then STRINGIFY_AWE(version) will return the string "version", not "4" 32 // To expand "version" to its value before making the string, use STRINGIFY(version) instead 33 #define STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s) # s 34 #define STRINGIFY(s) STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s) 35 36 // *************************************************************************** 37 #if COMPILER_LIKES_PRAGMA_MARK 38 #pragma mark - DNS Protocol Constants 39 #endif 40 41 typedef enum 42 { 43 kDNSFlag0_QR_Mask = 0x80, // Query or response? 44 kDNSFlag0_QR_Query = 0x00, 45 kDNSFlag0_QR_Response = 0x80, 46 47 kDNSFlag0_OP_Mask = 0x78, // Operation type 48 kDNSFlag0_OP_StdQuery = 0x00, 49 kDNSFlag0_OP_Subscribe = 0x06, 50 kDNSFlag0_OP_UnSubscribe = 0x07, 51 kDNSFlag0_OP_Iquery = 0x08, 52 kDNSFlag0_OP_Status = 0x10, 53 kDNSFlag0_OP_Unused3 = 0x18, 54 kDNSFlag0_OP_Notify = 0x20, 55 kDNSFlag0_OP_Update = 0x28, 56 57 kDNSFlag0_QROP_Mask = kDNSFlag0_QR_Mask | kDNSFlag0_OP_Mask, 58 59 kDNSFlag0_AA = 0x04, // Authoritative Answer? 60 kDNSFlag0_TC = 0x02, // Truncated? 61 kDNSFlag0_RD = 0x01, // Recursion Desired? 62 kDNSFlag1_RA = 0x80, // Recursion Available? 63 64 kDNSFlag1_Zero = 0x40, // Reserved; must be zero 65 kDNSFlag1_AD = 0x20, // Authentic Data [RFC 2535] 66 kDNSFlag1_CD = 0x10, // Checking Disabled [RFC 2535] 67 68 kDNSFlag1_RC_Mask = 0x0F, // Response code 69 kDNSFlag1_RC_NoErr = 0x00, 70 kDNSFlag1_RC_FormErr = 0x01, 71 kDNSFlag1_RC_ServFail = 0x02, 72 kDNSFlag1_RC_NXDomain = 0x03, 73 kDNSFlag1_RC_NotImpl = 0x04, 74 kDNSFlag1_RC_Refused = 0x05, 75 kDNSFlag1_RC_YXDomain = 0x06, 76 kDNSFlag1_RC_YXRRSet = 0x07, 77 kDNSFlag1_RC_NXRRSet = 0x08, 78 kDNSFlag1_RC_NotAuth = 0x09, 79 kDNSFlag1_RC_NotZone = 0x0A 80 } DNS_Flags; 81 82 typedef enum 83 { 84 TSIG_ErrBadSig = 16, 85 TSIG_ErrBadKey = 17, 86 TSIG_ErrBadTime = 18 87 } TSIG_ErrorCode; 88 89 90 // *************************************************************************** 91 #if COMPILER_LIKES_PRAGMA_MARK 92 #pragma mark - 93 #pragma mark - General Utility Functions 94 #endif 95 96 extern NetworkInterfaceInfo *GetFirstActiveInterface(NetworkInterfaceInfo *intf); 97 extern mDNSInterfaceID GetNextActiveInterfaceID(const NetworkInterfaceInfo *intf); 98 99 extern mDNSu32 mDNSRandom(mDNSu32 max); // Returns pseudo-random result from zero to max inclusive 100 101 // *************************************************************************** 102 #if COMPILER_LIKES_PRAGMA_MARK 103 #pragma mark - 104 #pragma mark - Domain Name Utility Functions 105 #endif 106 107 #define mDNSSubTypeLabel "\x04_sub" 108 109 #define mDNSIsDigit(X) ((X) >= '0' && (X) <= '9') 110 #define mDNSIsUpperCase(X) ((X) >= 'A' && (X) <= 'Z') 111 #define mDNSIsLowerCase(X) ((X) >= 'a' && (X) <= 'z') 112 #define mDNSIsLetter(X) (mDNSIsUpperCase(X) || mDNSIsLowerCase(X)) 113 114 #define mDNSValidHostChar(X, notfirst, notlast) (mDNSIsLetter(X) || mDNSIsDigit(X) || ((notfirst) && (notlast) && (X) == '-') ) 115 116 extern mDNSu16 CompressedDomainNameLength(const domainname *const name, const domainname *parent); 117 extern int CountLabels(const domainname *d); 118 extern const domainname *SkipLeadingLabels(const domainname *d, int skip); 119 120 extern mDNSu32 TruncateUTF8ToLength(mDNSu8 *string, mDNSu32 length, mDNSu32 max); 121 extern mDNSBool LabelContainsSuffix(const domainlabel *const name, const mDNSBool RichText); 122 extern mDNSu32 RemoveLabelSuffix(domainlabel *name, mDNSBool RichText); 123 extern void AppendLabelSuffix(domainlabel *const name, mDNSu32 val, const mDNSBool RichText); 124 #define ValidateDomainName(N) (DomainNameLength(N) <= MAX_DOMAIN_NAME) 125 126 // *************************************************************************** 127 #if COMPILER_LIKES_PRAGMA_MARK 128 #pragma mark - 129 #pragma mark - Resource Record Utility Functions 130 #endif 131 132 // IdenticalResourceRecord returns true if two resources records have 133 // the same name, type, class, and identical rdata (InterfaceID and TTL may differ) 134 135 // IdenticalSameNameRecord is the same, except it skips the expensive SameDomainName() check, 136 // which is at its most expensive and least useful in cases where we know in advance that the names match 137 138 // Note: The dominant use of IdenticalResourceRecord is from ProcessQuery(), handling known-answer lists. In this case 139 // it's common to have a whole bunch or records with exactly the same name (e.g. "_http._tcp.local") but different RDATA. 140 // The SameDomainName() check is expensive when the names match, and in this case *all* the names match, so we 141 // used to waste a lot of CPU time verifying that the names match, only then to find that the RDATA is different. 142 // We observed mDNSResponder spending 30% of its total CPU time on this single task alone. 143 // By swapping the checks so that we check the RDATA first, we can quickly detect when it's different 144 // (99% of the time) and then bail out before we waste time on the expensive SameDomainName() check. 145 146 #define IdenticalResourceRecord(r1,r2) ( \ 147 (r1)->rrtype == (r2)->rrtype && \ 148 (r1)->rrclass == (r2)->rrclass && \ 149 (r1)->namehash == (r2)->namehash && \ 150 (r1)->rdlength == (r2)->rdlength && \ 151 (r1)->rdatahash == (r2)->rdatahash && \ 152 SameRDataBody((r1), &(r2)->rdata->u, SameDomainName) && \ 153 SameDomainName((r1)->name, (r2)->name)) 154 155 #define IdenticalSameNameRecord(r1,r2) ( \ 156 (r1)->rrtype == (r2)->rrtype && \ 157 (r1)->rrclass == (r2)->rrclass && \ 158 (r1)->rdlength == (r2)->rdlength && \ 159 (r1)->rdatahash == (r2)->rdatahash && \ 160 SameRDataBody((r1), &(r2)->rdata->u, SameDomainName)) 161 162 // A given RRType answers a QuestionType if RRType is CNAME, or types match, or QuestionType is ANY, 163 // or the RRType is NSEC and positively asserts the nonexistence of the type being requested 164 #define RRTypeAnswersQuestionType(R,Q) ((R)->rrtype == kDNSType_CNAME || (R)->rrtype == (Q) || (Q) == kDNSQType_ANY || RRAssertsNonexistence((R),(Q))) 165 // Unicast NSEC records have the NSEC bit set whereas the multicast NSEC ones don't 166 #define UNICAST_NSEC(rr) ((rr)->rrtype == kDNSType_NSEC && RRAssertsExistence((rr), kDNSType_NSEC)) 167 168 extern mDNSu32 RDataHashValue(const ResourceRecord *const rr); 169 extern mDNSBool SameRDataBody(const ResourceRecord *const r1, const RDataBody *const r2, DomainNameComparisonFn *samename); 170 extern mDNSBool SameNameRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q); 171 extern mDNSBool ResourceRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q); 172 extern mDNSBool AnyTypeRecordAnswersQuestion (const ResourceRecord *const rr, const DNSQuestion *const q); 173 extern mDNSBool ResourceRecordAnswersUnicastResponse(const ResourceRecord *const rr, const DNSQuestion *const q); 174 extern mDNSBool LocalOnlyRecordAnswersQuestion(AuthRecord *const rr, const DNSQuestion *const q); 175 extern mDNSu16 GetRDLength(const ResourceRecord *const rr, mDNSBool estimate); 176 extern mDNSBool ValidateRData(const mDNSu16 rrtype, const mDNSu16 rdlength, const RData *const rd); 177 extern mStatus DNSNameToLowerCase(domainname *d, domainname *result); 178 179 #define GetRRDomainNameTarget(RR) ( \ 180 ((RR)->rrtype == kDNSType_NS || (RR)->rrtype == kDNSType_CNAME || (RR)->rrtype == kDNSType_PTR || (RR)->rrtype == kDNSType_DNAME) ? &(RR)->rdata->u.name : \ 181 ((RR)->rrtype == kDNSType_MX || (RR)->rrtype == kDNSType_AFSDB || (RR)->rrtype == kDNSType_RT || (RR)->rrtype == kDNSType_KX ) ? &(RR)->rdata->u.mx.exchange : \ 182 ((RR)->rrtype == kDNSType_SRV ) ? &(RR)->rdata->u.srv.target : mDNSNULL ) 183 184 #define LocalRecordReady(X) ((X)->resrec.RecordType != kDNSRecordTypeUnique) 185 186 // *************************************************************************** 187 #if COMPILER_LIKES_PRAGMA_MARK 188 #pragma mark - 189 #pragma mark - DNS Message Creation Functions 190 #endif 191 192 extern void InitializeDNSMessage(DNSMessageHeader *h, mDNSOpaque16 id, mDNSOpaque16 flags); 193 extern const mDNSu8 *FindCompressionPointer(const mDNSu8 *const base, const mDNSu8 *const end, const mDNSu8 *const domname); 194 extern mDNSu8 *putDomainNameAsLabels(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name); 195 extern mDNSu8 *putRData(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const ResourceRecord *const rr); 196 197 // If we have a single large record to put in the packet, then we allow the packet to be up to 9K bytes, 198 // but in the normal case we try to keep the packets below 1500 to avoid IP fragmentation on standard Ethernet 199 200 #define AllowedRRSpace(msg) (((msg)->h.numAnswers || (msg)->h.numAuthorities || (msg)->h.numAdditionals) ? NormalMaxDNSMessageData : AbsoluteMaxDNSMessageData) 201 202 extern mDNSu8 *PutResourceRecordTTLWithLimit(DNSMessage *const msg, mDNSu8 *ptr, mDNSu16 *count, ResourceRecord *rr, mDNSu32 ttl, const mDNSu8 *limit); 203 204 #define PutResourceRecordTTL(msg, ptr, count, rr, ttl) \ 205 PutResourceRecordTTLWithLimit((msg), (ptr), (count), (rr), (ttl), (msg)->data + AllowedRRSpace(msg)) 206 207 #define PutResourceRecordTTLJumbo(msg, ptr, count, rr, ttl) \ 208 PutResourceRecordTTLWithLimit((msg), (ptr), (count), (rr), (ttl), (msg)->data + AbsoluteMaxDNSMessageData) 209 210 #define PutResourceRecord(MSG, P, C, RR) PutResourceRecordTTL((MSG), (P), (C), (RR), (RR)->rroriginalttl) 211 212 // The PutRR_OS variants assume a local variable 'm', put build the packet at m->omsg, 213 // and assume local variables 'OwnerRecordSpace' & 'TraceRecordSpace' indicating how many bytes (if any) to reserve to add an OWNER/TRACER option at the end 214 #define PutRR_OS_TTL(ptr, count, rr, ttl) \ 215 PutResourceRecordTTLWithLimit(&m->omsg, (ptr), (count), (rr), (ttl), m->omsg.data + AllowedRRSpace(&m->omsg) - OwnerRecordSpace - TraceRecordSpace) 216 217 #define PutRR_OS(P, C, RR) PutRR_OS_TTL((P), (C), (RR), (RR)->rroriginalttl) 218 219 extern mDNSu8 *putQuestion(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name, mDNSu16 rrtype, mDNSu16 rrclass); 220 extern mDNSu8 *putZone(DNSMessage *const msg, mDNSu8 *ptr, mDNSu8 *limit, const domainname *zone, mDNSOpaque16 zoneClass); 221 extern mDNSu8 *putPrereqNameNotInUse(const domainname *const name, DNSMessage *const msg, mDNSu8 *const ptr, mDNSu8 *const end); 222 extern mDNSu8 *putDeletionRecord(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr); 223 extern mDNSu8 *putDeletionRecordWithLimit(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr, mDNSu8 *limit); 224 extern mDNSu8 *putDeleteRRSetWithLimit(DNSMessage *msg, mDNSu8 *ptr, const domainname *name, mDNSu16 rrtype, mDNSu8 *limit); 225 extern mDNSu8 *putDeleteAllRRSets(DNSMessage *msg, mDNSu8 *ptr, const domainname *name); 226 extern mDNSu8 *putUpdateLease(DNSMessage *msg, mDNSu8 *ptr, mDNSu32 lease); 227 extern mDNSu8 *putUpdateLeaseWithLimit(DNSMessage *msg, mDNSu8 *ptr, mDNSu32 lease, mDNSu8 *limit); 228 229 extern mDNSu8 *putHINFO(const mDNS *const m, DNSMessage *const msg, mDNSu8 *ptr, DomainAuthInfo *authInfo, mDNSu8 *limit); 230 extern mDNSu8 *putDNSSECOption(DNSMessage *msg, mDNSu8 *end, mDNSu8 *limit); 231 extern int baseEncode(char *buffer, int blen, const mDNSu8 *data, int len, int encAlg); 232 extern void NSEC3Parse(const ResourceRecord *const rr, mDNSu8 **salt, int *hashLength, mDNSu8 **nxtName, int *bitmaplen, mDNSu8 **bitmap); 233 234 extern const mDNSu8 *NSEC3HashName(const domainname *name, rdataNSEC3 *nsec3, const mDNSu8 *AnonData, int AnonDataLen, 235 const mDNSu8 hash[NSEC3_MAX_HASH_LEN], int *dlen); 236 237 // *************************************************************************** 238 #if COMPILER_LIKES_PRAGMA_MARK 239 #pragma mark - 240 #pragma mark - DNS Message Parsing Functions 241 #endif 242 243 #define HashSlotFromNameHash(X) ((X) % CACHE_HASH_SLOTS) 244 extern mDNSu32 DomainNameHashValue(const domainname *const name); 245 extern void SetNewRData(ResourceRecord *const rr, RData *NewRData, mDNSu16 rdlength); 246 extern const mDNSu8 *skipDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end); 247 extern const mDNSu8 *getDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end, 248 domainname *const name); 249 extern const mDNSu8 *skipResourceRecord(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end); 250 extern const mDNSu8 *GetLargeResourceRecord(mDNS *const m, const DNSMessage * const msg, const mDNSu8 *ptr, 251 const mDNSu8 * end, const mDNSInterfaceID InterfaceID, mDNSu8 RecordType, LargeCacheRecord *const largecr); 252 extern mDNSBool SetRData(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *end, 253 LargeCacheRecord *const largecr, mDNSu16 rdlength); 254 extern const mDNSu8 *skipQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end); 255 extern const mDNSu8 *getQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end, const mDNSInterfaceID InterfaceID, 256 DNSQuestion *question); 257 extern const mDNSu8 *LocateAnswers(const DNSMessage *const msg, const mDNSu8 *const end); 258 extern const mDNSu8 *LocateAuthorities(const DNSMessage *const msg, const mDNSu8 *const end); 259 extern const mDNSu8 *LocateAdditionals(const DNSMessage *const msg, const mDNSu8 *const end); 260 extern const mDNSu8 *LocateOptRR(const DNSMessage *const msg, const mDNSu8 *const end, int minsize); 261 extern const rdataOPT *GetLLQOptData(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end); 262 extern mDNSBool GetPktLease(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end, mDNSu32 *const lease); 263 extern void DumpPacket(mDNS *const m, mStatus status, mDNSBool sent, char *transport, 264 const mDNSAddr *srcaddr, mDNSIPPort srcport, 265 const mDNSAddr *dstaddr, mDNSIPPort dstport, const DNSMessage *const msg, const mDNSu8 *const end); 266 extern mDNSBool RRAssertsNonexistence(const ResourceRecord *const rr, mDNSu16 type); 267 extern mDNSBool RRAssertsExistence(const ResourceRecord *const rr, mDNSu16 type); 268 extern mDNSBool BitmapTypeCheck(mDNSu8 *bmap, int bitmaplen, mDNSu16 type); 269 270 extern mDNSu16 swap16(mDNSu16 x); 271 extern mDNSu32 swap32(mDNSu32 x); 272 273 // *************************************************************************** 274 #if COMPILER_LIKES_PRAGMA_MARK 275 #pragma mark - 276 #pragma mark - Packet Sending Functions 277 #endif 278 279 extern mStatus mDNSSendDNSMessage(mDNS *const m, DNSMessage *const msg, mDNSu8 *end, 280 mDNSInterfaceID InterfaceID, UDPSocket *src, const mDNSAddr *dst, 281 mDNSIPPort dstport, TCPSocket *sock, DomainAuthInfo *authInfo, 282 mDNSBool useBackgroundTrafficClass); 283 284 // *************************************************************************** 285 #if COMPILER_LIKES_PRAGMA_MARK 286 #pragma mark - 287 #pragma mark - RR List Management & Task Management 288 #endif 289 290 extern void ShowTaskSchedulingError(mDNS *const m); 291 extern void mDNS_Lock_(mDNS *const m, const char * const functionname); 292 extern void mDNS_Unlock_(mDNS *const m, const char * const functionname); 293 294 #if defined(_WIN32) 295 #define __func__ __FUNCTION__ 296 #endif 297 298 #define mDNS_Lock(X) mDNS_Lock_((X), __func__) 299 300 #define mDNS_Unlock(X) mDNS_Unlock_((X), __func__) 301 302 #define mDNS_CheckLock(X) \ 303 if ((X)->mDNS_busy != (X)->mDNS_reentrancy+1) LogMsg("%s: Lock not held! mDNS_busy (%ld) mDNS_reentrancy (%ld)", __func__, (X)->mDNS_busy, (X)->mDNS_reentrancy) 304 305 #define mDNS_DropLockBeforeCallback() do { m->mDNS_reentrancy++; \ 306 if (m->mDNS_busy != m->mDNS_reentrancy) LogMsg("%s: Locking Failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, m->mDNS_busy, m->mDNS_reentrancy); \ 307 } while (0) 308 309 #define mDNS_ReclaimLockAfterCallback() do { \ 310 if (m->mDNS_busy != m->mDNS_reentrancy) LogMsg("%s: Unlocking Failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, m->mDNS_busy, m->mDNS_reentrancy); \ 311 m->mDNS_reentrancy--; } while (0) 312 313 #ifdef __cplusplus 314 } 315 #endif 316 317 #endif // __DNSCOMMON_H_ 318