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