mDNSCore/DNSCommon.h

   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 mDNSIsDigit(X)     ((X) >= '0' && (X) <= '9')
 105 #define mDNSIsUpperCase(X) ((X) >= 'A' && (X) <= 'Z')
 106 #define mDNSIsLowerCase(X) ((X) >= 'a' && (X) <= 'z')
 107 #define mDNSIsLetter(X)    (mDNSIsUpperCase(X) || mDNSIsLowerCase(X))
 108
 109 #define mDNSValidHostChar(X, notfirst, notlast) (mDNSIsLetter(X) || mDNSIsDigit(X) || ((notfirst) && (notlast) && (X) == '-') )
 110
 111 extern mDNSu16 CompressedDomainNameLength(const domainname *const name, const domainname *parent);
 112 extern int CountLabels(const domainname *d);
 113 extern const domainname *SkipLeadingLabels(const domainname *d, int skip);
 114
 115 extern mDNSu32 TruncateUTF8ToLength(mDNSu8 *string, mDNSu32 length, mDNSu32 max);
 116 extern mDNSBool LabelContainsSuffix(const domainlabel *const name, const mDNSBool RichText);
 117 extern mDNSu32 RemoveLabelSuffix(domainlabel *name, mDNSBool RichText);
 118 extern void AppendLabelSuffix(domainlabel *const name, mDNSu32 val, const mDNSBool RichText);
 119 #define ValidateDomainName(N) (DomainNameLength(N) <= MAX_DOMAIN_NAME)
 120
 121 // ***************************************************************************
 122 #if COMPILER_LIKES_PRAGMA_MARK
 123 #pragma mark -
 124 #pragma mark - Resource Record Utility Functions
 125 #endif
 126
 127 // IdenticalResourceRecord returns true if two resources records have
 128 // the same name, type, class, and identical rdata (InterfaceID and TTL may differ)
 129
 130 // IdenticalSameNameRecord is the same, except it skips the expensive SameDomainName() check,
 131 // which is at its most expensive and least useful in cases where we know in advance that the names match
 132
 133 // Note: The dominant use of IdenticalResourceRecord is from ProcessQuery(), handling known-answer lists. In this case
 134 // it's common to have a whole bunch or records with exactly the same name (e.g. "_http._tcp.local") but different RDATA.
 135 // The SameDomainName() check is expensive when the names match, and in this case *all* the names match, so we
 136 // used to waste a lot of CPU time verifying that the names match, only then to find that the RDATA is different.
 137 // We observed mDNSResponder spending 30% of its total CPU time on this single task alone.
 138 // By swapping the checks so that we check the RDATA first, we can quickly detect when it's different
 139 // (99% of the time) and then bail out before we waste time on the expensive SameDomainName() check.
 140
 141 #define IdenticalResourceRecord(r1,r2) ( \
 142         (r1)->rrtype    == (r2)->rrtype      && \
 143         (r1)->rrclass   == (r2)->rrclass     && \
 144         (r1)->namehash  == (r2)->namehash    && \
 145         (r1)->rdlength  == (r2)->rdlength    && \
 146         (r1)->rdatahash == (r2)->rdatahash   && \
 147         SameRDataBody((r1), &(r2)->rdata->u, SameDomainName) && \
 148         SameDomainName((r1)->name, (r2)->name))
 149
 150 #define IdenticalSameNameRecord(r1,r2) ( \
 151         (r1)->rrtype    == (r2)->rrtype      && \
 152         (r1)->rrclass   == (r2)->rrclass     && \
 153         (r1)->rdlength  == (r2)->rdlength    && \
 154         (r1)->rdatahash == (r2)->rdatahash   && \
 155         SameRDataBody((r1), &(r2)->rdata->u, SameDomainName))
 156
 157 // A given RRType answers a QuestionType if RRType is CNAME, or types match, or QuestionType is ANY,
 158 // or the RRType is NSEC and positively asserts the nonexistence of the type being requested
 159 #define RRTypeAnswersQuestionType(R,Q) ((R)->rrtype == kDNSType_CNAME || (R)->rrtype == (Q) || (Q) == kDNSQType_ANY || RRAssertsNonexistence((R),(Q)))
 160 // Unicast NSEC records have the NSEC bit set whereas the multicast NSEC ones don't
 161 #define UNICAST_NSEC(rr) ((rr)->rrtype == kDNSType_NSEC && RRAssertsExistence((rr), kDNSType_NSEC))
 162
 163 extern mDNSu32 RDataHashValue(const ResourceRecord *const rr);
 164 extern mDNSBool SameRDataBody(const ResourceRecord *const r1, const RDataBody *const r2, DomainNameComparisonFn *samename);
 165 extern mDNSBool SameNameRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q);
 166 extern mDNSBool ResourceRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q);
 167 extern mDNSBool AnyTypeRecordAnswersQuestion (const ResourceRecord *const rr, const DNSQuestion *const q);
 168 extern mDNSBool ResourceRecordAnswersUnicastResponse(const ResourceRecord *const rr, const DNSQuestion *const q);
 169 extern mDNSBool LocalOnlyRecordAnswersQuestion(AuthRecord *const rr, const DNSQuestion *const q);
 170 extern mDNSu16 GetRDLength(const ResourceRecord *const rr, mDNSBool estimate);
 171 extern mDNSBool ValidateRData(const mDNSu16 rrtype, const mDNSu16 rdlength, const RData *const rd);
 172
 173 #define GetRRDomainNameTarget(RR) (                                                                          \
 174         ((RR)->rrtype == kDNSType_NS || (RR)->rrtype == kDNSType_CNAME || (RR)->rrtype == kDNSType_PTR || (RR)->rrtype == kDNSType_DNAME) ? &(RR)->rdata->u.name        : \
 175         ((RR)->rrtype == kDNSType_MX || (RR)->rrtype == kDNSType_AFSDB || (RR)->rrtype == kDNSType_RT  || (RR)->rrtype == kDNSType_KX   ) ? &(RR)->rdata->u.mx.exchange : \
 176         ((RR)->rrtype == kDNSType_SRV                                  ) ? &(RR)->rdata->u.srv.target : mDNSNULL )
 177
 178 #define LocalRecordReady(X) ((X)->resrec.RecordType != kDNSRecordTypeUnique)
 179
 180 // ***************************************************************************
 181 #if COMPILER_LIKES_PRAGMA_MARK
 182 #pragma mark -
 183 #pragma mark - DNS Message Creation Functions
 184 #endif
 185
 186 extern void InitializeDNSMessage(DNSMessageHeader *h, mDNSOpaque16 id, mDNSOpaque16 flags);
 187 extern const mDNSu8 *FindCompressionPointer(const mDNSu8 *const base, const mDNSu8 *const end, const mDNSu8 *const domname);
 188 extern mDNSu8 *putDomainNameAsLabels(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name);
 189 extern mDNSu8 *putRData(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const ResourceRecord *const rr);
 190
 191 // If we have a single large record to put in the packet, then we allow the packet to be up to 9K bytes,
 192 // but in the normal case we try to keep the packets below 1500 to avoid IP fragmentation on standard Ethernet
 193
 194 #define AllowedRRSpace(msg) (((msg)->h.numAnswers || (msg)->h.numAuthorities || (msg)->h.numAdditionals) ? NormalMaxDNSMessageData : AbsoluteMaxDNSMessageData)
 195
 196 extern mDNSu8 *PutResourceRecordTTLWithLimit(DNSMessage *const msg, mDNSu8 *ptr, mDNSu16 *count, ResourceRecord *rr, mDNSu32 ttl, const mDNSu8 *limit);
 197
 198 #define PutResourceRecordTTL(msg, ptr, count, rr, ttl) \
 199     PutResourceRecordTTLWithLimit((msg), (ptr), (count), (rr), (ttl), (msg)->data + AllowedRRSpace(msg))
 200
 201 #define PutResourceRecordTTLJumbo(msg, ptr, count, rr, ttl) \
 202     PutResourceRecordTTLWithLimit((msg), (ptr), (count), (rr), (ttl), (msg)->data + AbsoluteMaxDNSMessageData)
 203
 204 #define PutResourceRecord(MSG, P, C, RR) PutResourceRecordTTL((MSG), (P), (C), (RR), (RR)->rroriginalttl)
 205
 206 // The PutRR_OS variants assume a local variable 'm', put build the packet at m->omsg,
 207 // and assume a local variable 'OwnerRecordSpace' indicating how many bytes (if any) to reserve to add an OWNER option at the end
 208 #define PutRR_OS_TTL(ptr, count, rr, ttl) \
 209     PutResourceRecordTTLWithLimit(&m->omsg, (ptr), (count), (rr), (ttl), m->omsg.data + AllowedRRSpace(&m->omsg) - OwnerRecordSpace)
 210
 211 #define PutRR_OS(P, C, RR) PutRR_OS_TTL((P), (C), (RR), (RR)->rroriginalttl)
 212
 213 extern mDNSu8 *putQuestion(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name, mDNSu16 rrtype, mDNSu16 rrclass);
 214 extern mDNSu8 *putZone(DNSMessage *const msg, mDNSu8 *ptr, mDNSu8 *limit, const domainname *zone, mDNSOpaque16 zoneClass);
 215 extern mDNSu8 *putPrereqNameNotInUse(const domainname *const name, DNSMessage *const msg, mDNSu8 *const ptr, mDNSu8 *const end);
 216 extern mDNSu8 *putDeletionRecord(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr);
 217 extern mDNSu8 *putDeletionRecordWithLimit(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr, mDNSu8 *limit);
 218 extern mDNSu8 *putDeleteRRSetWithLimit(DNSMessage *msg, mDNSu8 *ptr, const domainname *name, mDNSu16 rrtype, mDNSu8 *limit);
 219 extern mDNSu8 *putDeleteAllRRSets(DNSMessage *msg, mDNSu8 *ptr, const domainname *name);
 220 extern mDNSu8 *putUpdateLease(DNSMessage *msg, mDNSu8 *end, mDNSu32 lease);
 221 extern mDNSu8 *putUpdateLeaseWithLimit(DNSMessage *msg, mDNSu8 *ptr, mDNSu32 lease, mDNSu8 *limit);
 222
 223 extern mDNSu8 *putHINFO(const mDNS *const m, DNSMessage *const msg, mDNSu8 *ptr, DomainAuthInfo *authInfo, mDNSu8 *limit);
 224 mDNSexport mDNSu8 *putDNSSECOption(DNSMessage *msg, mDNSu8 *end, mDNSu8 *limit);
 225
 226 // ***************************************************************************
 227 #if COMPILER_LIKES_PRAGMA_MARK
 228 #pragma mark -
 229 #pragma mark - DNS Message Parsing Functions
 230 #endif
 231
 232 #define AuthHashSlot(X) (DomainNameHashValue(X) % AUTH_HASH_SLOTS)
 233 #define HashSlot(X) (DomainNameHashValue(X) % CACHE_HASH_SLOTS)
 234 extern mDNSu32 DomainNameHashValue(const domainname *const name);
 235 extern void SetNewRData(ResourceRecord *const rr, RData *NewRData, mDNSu16 rdlength);
 236 extern const mDNSu8 *skipDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end);
 237 extern const mDNSu8 *getDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end,
 238                                    domainname *const name);
 239 extern const mDNSu8 *skipResourceRecord(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end);
 240 extern const mDNSu8 *GetLargeResourceRecord(mDNS *const m, const DNSMessage * const msg, const mDNSu8 *ptr,
 241                                             const mDNSu8 * end, const mDNSInterfaceID InterfaceID, mDNSu8 RecordType, LargeCacheRecord *const largecr);
 242 extern mDNSBool SetRData(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *end,
 243     LargeCacheRecord *const largecr, mDNSu16 rdlength);
 244 extern const mDNSu8 *skipQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end);
 245 extern const mDNSu8 *getQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end, const mDNSInterfaceID InterfaceID,
 246                                  DNSQuestion *question);
 247 extern const mDNSu8 *LocateAnswers(const DNSMessage *const msg, const mDNSu8 *const end);
 248 extern const mDNSu8 *LocateAuthorities(const DNSMessage *const msg, const mDNSu8 *const end);
 249 extern const mDNSu8 *LocateAdditionals(const DNSMessage *const msg, const mDNSu8 *const end);
 250 extern const mDNSu8 *LocateOptRR(const DNSMessage *const msg, const mDNSu8 *const end, int minsize);
 251 extern const rdataOPT *GetLLQOptData(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end);
 252 extern mDNSu32 GetPktLease(mDNS *m, DNSMessage *msg, const mDNSu8 *end);
 253 extern void DumpPacket(mDNS *const m, mStatus status, mDNSBool sent, char *transport,
 254                        const mDNSAddr *srcaddr, mDNSIPPort srcport,
 255                        const mDNSAddr *dstaddr, mDNSIPPort dstport, const DNSMessage *const msg, const mDNSu8 *const end);
 256 extern mDNSBool RRAssertsNonexistence(const ResourceRecord *const rr, mDNSu16 type);
 257 extern mDNSBool RRAssertsExistence(const ResourceRecord *const rr, mDNSu16 type);
 258
 259 extern mDNSu16 swap16(mDNSu16 x);
 260 extern mDNSu32 swap32(mDNSu32 x);
 261
 262 // ***************************************************************************
 263 #if COMPILER_LIKES_PRAGMA_MARK
 264 #pragma mark -
 265 #pragma mark - Packet Sending Functions
 266 #endif
 267
 268 extern mStatus mDNSSendDNSMessage(mDNS *const m, DNSMessage *const msg, mDNSu8 *end,
 269                                   mDNSInterfaceID InterfaceID, UDPSocket *src, const mDNSAddr *dst,
 270                                   mDNSIPPort dstport, TCPSocket *sock, DomainAuthInfo *authInfo,
 271                                   mDNSBool useBackgroundTrafficClass);
 272
 273 // ***************************************************************************
 274 #if COMPILER_LIKES_PRAGMA_MARK
 275 #pragma mark -
 276 #pragma mark - RR List Management & Task Management
 277 #endif
 278
 279 extern void ShowTaskSchedulingError(mDNS *const m);
 280 extern void mDNS_Lock_(mDNS *const m, const char * const functionname);
 281 extern void mDNS_Unlock_(mDNS *const m, const char * const functionname);
 282
 283 #if defined(_WIN32)
 284  #define __func__ __FUNCTION__
 285 #endif
 286
 287 #define mDNS_Lock(X) mDNS_Lock_((X), __func__)
 288
 289 #define mDNS_Unlock(X) mDNS_Unlock_((X), __func__)
 290
 291 #define mDNS_CheckLock(X) { if ((X)->mDNS_busy != (X)->mDNS_reentrancy+1) \
 292                             LogMsg("%s: Lock not held! mDNS_busy (%ld) mDNS_reentrancy (%ld)", __func__, (X)->mDNS_busy, (X)->mDNS_reentrancy); }
 293
 294 #define mDNS_DropLockBeforeCallback() do { m->mDNS_reentrancy++; \
 295                                            if (m->mDNS_busy != m->mDNS_reentrancy) LogMsg("%s: Locking Failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, m->mDNS_busy, m->mDNS_reentrancy);                                                                                                                                                                  \
 296 } while (0)
 297
 298 #define mDNS_ReclaimLockAfterCallback() do { \
 299         if (m->mDNS_busy != m->mDNS_reentrancy) LogMsg("%s: Unlocking Failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, m->mDNS_busy, m->mDNS_reentrancy);                                                                                                                                                                    \
 300         m->mDNS_reentrancy--; } while (0)
 301
 302 #ifdef  __cplusplus
 303 }
 304 #endif
 305
 306 #endif // __DNSCOMMON_H_