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     Change History (most recent first):
  18
  19 $Log: DNSCommon.h,v $
  20 Revision 1.59  2008/03/14 19:58:38  mcguire
  21 <rdar://problem/5500969> BTMM: Need ability to identify version of mDNSResponder client
  22 Make sure we add the record when sending LLQ refreshes
  23
  24 Revision 1.58  2008/03/06 21:26:10  cheshire
  25 Moved duplicated STRINGIFY macro from individual C files to DNSCommon.h
  26
  27 Revision 1.57  2007/12/13 20:20:17  cheshire
  28 Minor efficiency tweaks -- converted IdenticalResourceRecord, IdenticalSameNameRecord, and
  29 SameRData from functions to macros, which allows the code to be inlined (the compiler can't
  30 inline a function defined in a different compilation unit) and therefore optimized better.
  31
  32 Revision 1.56  2007/12/13 00:13:03  cheshire
  33 Simplified RDataHashValue to take a single ResourceRecord pointer, instead of separate rdlength and RDataBody
  34
  35 Revision 1.55  2007/12/13 00:09:28  cheshire
  36 For completeness added MX, AFSDB, RT, KX to list of RRTYPES that are considered to have a target domainname in their rdata
  37
  38 Revision 1.54  2007/10/05 17:56:10  cheshire
  39 Move CountLabels and SkipLeadingLabels to DNSCommon.c so they're callable from other files
  40
  41 Revision 1.53  2007/09/27 17:42:49  cheshire
  42 Fix naming: for consistency, "kDNSFlag1_RC" should be "kDNSFlag1_RC_Mask"
  43
  44 Revision 1.52  2007/09/26 00:49:46  cheshire
  45 Improve packet logging to show sent and received packets,
  46 transport protocol (UDP/TCP/TLS) and source/destination address:port
  47
  48 Revision 1.51  2007/09/21 21:12:36  cheshire
  49 <rdar://problem/5498009> BTMM: Need to log updates and query packet contents
  50
  51 Revision 1.50  2007/09/20 01:12:06  cheshire
  52 Moved HashSlot(X) from mDNS.c to DNSCommon.h so it's usable in other files
  53
  54 Revision 1.49  2007/08/30 00:31:20  cheshire
  55 Improve "locking failure" debugging messages to show function name using __func__ macro
  56
  57 Revision 1.48  2007/05/25 00:25:44  cheshire
  58 <rdar://problem/5227737> Need to enhance putRData to output all current known types
  59
  60 Revision 1.47  2007/05/01 21:46:31  cheshire
  61 Move GetLLQOptData/GetPktLease from uDNS.c into DNSCommon.c so that dnsextd can use them
  62
  63 Revision 1.46  2007/04/22 20:18:10  cheshire
  64 Add comment about mDNSRandom()
  65
  66 Revision 1.45  2007/04/22 06:02:02  cheshire
  67 <rdar://problem/4615977> Query should immediately return failure when no server
  68
  69 Revision 1.44  2007/03/28 01:20:05  cheshire
  70 <rdar://problem/4883206> Improve/create logging for secure browse
  71
  72 Revision 1.43  2007/03/20 17:07:15  cheshire
  73 Rename "struct uDNS_TCPSocket_struct" to "TCPSocket", "struct uDNS_UDPSocket_struct" to "UDPSocket"
  74
  75 Revision 1.42  2007/03/10 03:26:44  cheshire
  76 <rdar://problem/4961667> uDNS: LLQ refresh response packet causes cached records to be removed from cache
  77
  78 Revision 1.41  2007/01/18 23:18:17  cheshire
  79 Source code tidying: Delete extraneous white space
  80
  81 Revision 1.40  2007/01/05 08:30:40  cheshire
  82 Trim excessive "$Log" checkin history from before 2006
  83 (checkin history still available via "cvs log ..." of course)
  84
  85 Revision 1.39  2007/01/04 21:45:20  cheshire
  86 Added mDNS_DropLockBeforeCallback/mDNS_ReclaimLockAfterCallback macros,
  87 to do additional lock sanity checking around callback invocations
  88
  89 Revision 1.38  2006/12/22 20:59:49  cheshire
  90 <rdar://problem/4742742> Read *all* DNS keys from keychain,
  91  not just key for the system-wide default registration domain
  92
  93 Revision 1.37  2006/08/14 23:24:22  cheshire
  94 Re-licensed mDNSResponder daemon source code under Apache License, Version 2.0
  95
  96 Revision 1.36  2006/07/05 22:56:07  cheshire
  97 <rdar://problem/4472014> Add Private DNS client functionality to mDNSResponder
  98 Update mDNSSendDNSMessage() to use uDNS_TCPSocket type instead of "int"
  99
 100 Revision 1.35  2006/06/29 07:42:14  cheshire
 101 <rdar://problem/3922989> Performance: Remove unnecessary SameDomainName() checks
 102
 103 Revision 1.34  2006/03/18 21:47:56  cheshire
 104 <rdar://problem/4073825> Improve logic for delaying packets after repeated interface transitions
 105
 106 Revision 1.33  2006/03/10 21:51:41  cheshire
 107 <rdar://problem/4111464> After record update, old record sometimes remains in cache
 108 Split out SameRDataBody() into a separate routine so it can be called from other code
 109
 110 */
 111
 112 #ifndef __DNSCOMMON_H_
 113 #define __DNSCOMMON_H_
 114
 115 #include "mDNSEmbeddedAPI.h"
 116
 117 #ifdef  __cplusplus
 118         extern "C" {
 119 #endif
 120
 121 //*************************************************************************************************************
 122 // Macros
 123
 124 // Note: The C preprocessor stringify operator ('#') makes a string from its argument, without macro expansion
 125 // e.g. If "version" is #define'd to be "4", then STRINGIFY_AWE(version) will return the string "version", not "4"
 126 // To expand "version" to its value before making the string, use STRINGIFY(version) instead
 127 #define STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s) #s
 128 #define STRINGIFY(s) STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s)
 129
 130 // ***************************************************************************
 131 #if COMPILER_LIKES_PRAGMA_MARK
 132 #pragma mark - DNS Protocol Constants
 133 #endif
 134
 135 typedef enum
 136         {
 137         kDNSFlag0_QR_Mask     = 0x80,           // Query or response?
 138         kDNSFlag0_QR_Query    = 0x00,
 139         kDNSFlag0_QR_Response = 0x80,
 140
 141         kDNSFlag0_OP_Mask     = 0x78,           // Operation type
 142         kDNSFlag0_OP_StdQuery = 0x00,
 143         kDNSFlag0_OP_Iquery   = 0x08,
 144         kDNSFlag0_OP_Status   = 0x10,
 145         kDNSFlag0_OP_Unused3  = 0x18,
 146         kDNSFlag0_OP_Notify   = 0x20,
 147         kDNSFlag0_OP_Update   = 0x28,
 148
 149         kDNSFlag0_QROP_Mask   = kDNSFlag0_QR_Mask | kDNSFlag0_OP_Mask,
 150
 151         kDNSFlag0_AA          = 0x04,           // Authoritative Answer?
 152         kDNSFlag0_TC          = 0x02,           // Truncated?
 153         kDNSFlag0_RD          = 0x01,           // Recursion Desired?
 154         kDNSFlag1_RA          = 0x80,           // Recursion Available?
 155
 156         kDNSFlag1_Zero        = 0x40,           // Reserved; must be zero
 157         kDNSFlag1_AD          = 0x20,           // Authentic Data [RFC 2535]
 158         kDNSFlag1_CD          = 0x10,           // Checking Disabled [RFC 2535]
 159
 160         kDNSFlag1_RC_Mask     = 0x0F,           // Response code
 161         kDNSFlag1_RC_NoErr    = 0x00,
 162         kDNSFlag1_RC_FmtErr   = 0x01,
 163         kDNSFlag1_RC_SrvErr   = 0x02,
 164         kDNSFlag1_RC_NXDomain = 0x03,
 165         kDNSFlag1_RC_NotImpl  = 0x04,
 166         kDNSFlag1_RC_Refused  = 0x05,
 167         kDNSFlag1_RC_YXDomain = 0x06,
 168         kDNSFlag1_RC_YXRRSet  = 0x07,
 169         kDNSFlag1_RC_NXRRSet  = 0x08,
 170         kDNSFlag1_RC_NotAuth  = 0x09,
 171         kDNSFlag1_RC_NotZone  = 0x0A
 172         } DNS_Flags;
 173
 174 typedef enum
 175         {
 176         TSIG_ErrBadSig  = 16,
 177         TSIG_ErrBadKey  = 17,
 178         TSIG_ErrBadTime = 18
 179         } TSIG_ErrorCode;
 180
 181 // ***************************************************************************
 182 #if COMPILER_LIKES_PRAGMA_MARK
 183 #pragma mark -
 184 #pragma mark - General Utility Functions
 185 #endif
 186
 187 extern const NetworkInterfaceInfo *GetFirstActiveInterface(const NetworkInterfaceInfo *intf);
 188 extern mDNSInterfaceID GetNextActiveInterfaceID(const NetworkInterfaceInfo *intf);
 189
 190 extern mDNSu32 mDNSRandom(mDNSu32 max);         // Returns pseudo-random result from zero to max inclusive
 191 extern mDNSu32 mDNSRandomFromFixedSeed(mDNSu32 seed, mDNSu32 max);
 192
 193 // ***************************************************************************
 194 #if COMPILER_LIKES_PRAGMA_MARK
 195 #pragma mark -
 196 #pragma mark - Domain Name Utility Functions
 197 #endif
 198
 199 #define mdnsIsDigit(X)     ((X) >= '0' && (X) <= '9')
 200 #define mDNSIsUpperCase(X) ((X) >= 'A' && (X) <= 'Z')
 201 #define mDNSIsLowerCase(X) ((X) >= 'a' && (X) <= 'z')
 202 #define mdnsIsLetter(X)    (mDNSIsUpperCase(X) || mDNSIsLowerCase(X))
 203
 204 #define mdnsValidHostChar(X, notfirst, notlast) (mdnsIsLetter(X) || mdnsIsDigit(X) || ((notfirst) && (notlast) && (X) == '-') )
 205
 206 extern mDNSu16 CompressedDomainNameLength(const domainname *const name, const domainname *parent);
 207 extern int CountLabels(const domainname *d);
 208 extern const domainname *SkipLeadingLabels(const domainname *d, int skip);
 209
 210 extern mDNSu32 TruncateUTF8ToLength(mDNSu8 *string, mDNSu32 length, mDNSu32 max);
 211 extern mDNSBool LabelContainsSuffix(const domainlabel *const name, const mDNSBool RichText);
 212 extern mDNSu32 RemoveLabelSuffix(domainlabel *name, mDNSBool RichText);
 213 extern void AppendLabelSuffix(domainlabel *name, mDNSu32 val, mDNSBool RichText);
 214 #define ValidateDomainName(N) (DomainNameLength(N) <= MAX_DOMAIN_NAME)
 215
 216 // ***************************************************************************
 217 #if COMPILER_LIKES_PRAGMA_MARK
 218 #pragma mark -
 219 #pragma mark - Resource Record Utility Functions
 220 #endif
 221
 222 // IdenticalResourceRecord returns true if two resources records have
 223 // the same name, type, class, and identical rdata (InterfaceID and TTL may differ)
 224
 225 // IdenticalSameNameRecord is the same, except it skips the expensive SameDomainName() check,
 226 // which is at its most expensive and least useful in cases where we know in advance that the names match
 227
 228 // Note: The dominant use of IdenticalResourceRecord is from ProcessQuery(), handling known-answer lists. In this case
 229 // it's common to have a whole bunch or records with exactly the same name (e.g. "_http._tcp.local") but different RDATA.
 230 // The SameDomainName() check is expensive when the names match, and in this case *all* the names match, so we
 231 // used to waste a lot of CPU time verifying that the names match, only then to find that the RDATA is different.
 232 // We observed mDNSResponder spending 30% of its total CPU time on this single task alone.
 233 // By swapping the checks so that we check the RDATA first, we can quickly detect when it's different
 234 // (99% of the time) and then bail out before we waste time on the expensive SameDomainName() check.
 235
 236 #define IdenticalResourceRecord(r1,r2) ( \
 237         (r1)->rrtype    == (r2)->rrtype      && \
 238         (r1)->rrclass   == (r2)->rrclass     && \
 239         (r1)->namehash  == (r2)->namehash    && \
 240         (r1)->rdlength  == (r2)->rdlength    && \
 241         (r1)->rdatahash == (r2)->rdatahash   && \
 242         SameRDataBody((r1), &(r2)->rdata->u) && \
 243         SameDomainName((r1)->name, (r2)->name))
 244
 245 #define IdenticalSameNameRecord(r1,r2) ( \
 246         (r1)->rrtype    == (r2)->rrtype      && \
 247         (r1)->rrclass   == (r2)->rrclass     && \
 248         (r1)->rdlength  == (r2)->rdlength    && \
 249         (r1)->rdatahash == (r2)->rdatahash   && \
 250         SameRDataBody((r1), &(r2)->rdata->u))
 251
 252 extern mDNSu32 RDataHashValue(const ResourceRecord *const rr);
 253 extern mDNSBool SameRDataBody(const ResourceRecord *const r1, const RDataBody *const r2);
 254 #define SameRData(r1,r2) ((r1)->rrtype == (r2)->rrtype && (r1)->rdlength == (r2)->rdlength && (r1)->rdatahash == (r2)->rdatahash && SameRDataBody((r1), &(r2)->rdata->u))
 255 extern mDNSBool ResourceRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q);
 256 extern mDNSBool SameNameRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q);
 257 extern mDNSu16 GetRDLength(const ResourceRecord *const rr, mDNSBool estimate);
 258 extern mDNSBool ValidateRData(const mDNSu16 rrtype, const mDNSu16 rdlength, const RData *const rd);
 259
 260 #define GetRRDomainNameTarget(RR) (                                                                          \
 261         ((RR)->rrtype == kDNSType_NS || (RR)->rrtype == kDNSType_CNAME || (RR)->rrtype == kDNSType_PTR || (RR)->rrtype == kDNSType_DNAME) ? &(RR)->rdata->u.name        : \
 262         ((RR)->rrtype == kDNSType_MX || (RR)->rrtype == kDNSType_AFSDB || (RR)->rrtype == kDNSType_RT  || (RR)->rrtype == kDNSType_KX   ) ? &(RR)->rdata->u.mx.exchange : \
 263         ((RR)->rrtype == kDNSType_SRV                                  ) ? &(RR)->rdata->u.srv.target : mDNSNULL )
 264
 265 #define LocalRecordReady(X) ((X)->resrec.RecordType != kDNSRecordTypeUnique && (X)->resrec.RecordType != kDNSRecordTypeDeregistering)
 266
 267 // ***************************************************************************
 268 #if COMPILER_LIKES_PRAGMA_MARK
 269 #pragma mark -
 270 #pragma mark - DNS Message Creation Functions
 271 #endif
 272
 273 extern void InitializeDNSMessage(DNSMessageHeader *h, mDNSOpaque16 id, mDNSOpaque16 flags);
 274 extern const mDNSu8 *FindCompressionPointer(const mDNSu8 *const base, const mDNSu8 *const end, const mDNSu8 *const domname);
 275 extern mDNSu8 *putDomainNameAsLabels(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name);
 276 extern mDNSu8 *putRData(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const ResourceRecord *const rr);
 277
 278 // If we have a single large record to put in the packet, then we allow the packet to be up to 9K bytes,
 279 // but in the normal case we try to keep the packets below 1500 to avoid IP fragmentation on standard Ethernet
 280 extern mDNSu8 *PutResourceRecordTTLWithLimit(DNSMessage *const msg, mDNSu8 *ptr, mDNSu16 *count, ResourceRecord *rr, mDNSu32 ttl, const mDNSu8 *limit);
 281 #define PutResourceRecordTTL(msg, ptr, count, rr, ttl) PutResourceRecordTTLWithLimit((msg), (ptr), (count), (rr), (ttl), \
 282         ((msg)->h.numAnswers || (msg)->h.numAuthorities || (msg)->h.numAdditionals) ? (msg)->data + NormalMaxDNSMessageData : (msg)->data + AbsoluteMaxDNSMessageData)
 283 #define PutResourceRecordTTLJumbo(msg, ptr, count, rr, ttl) PutResourceRecordTTLWithLimit((msg), (ptr), (count), (rr), (ttl), \
 284         (msg)->data + AbsoluteMaxDNSMessageData)
 285 extern mDNSu8 *PutResourceRecordCappedTTL(DNSMessage *const msg, mDNSu8 *ptr, mDNSu16 *count, ResourceRecord *rr, mDNSu32 maxttl);
 286 extern mDNSu8 *putEmptyResourceRecord(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, mDNSu16 *count, const AuthRecord *rr);
 287
 288 extern mDNSu8 *putQuestion(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name, mDNSu16 rrtype, mDNSu16 rrclass);
 289 extern mDNSu8 *putZone(DNSMessage *const msg, mDNSu8 *ptr, mDNSu8 *limit, const domainname *zone, mDNSOpaque16 zoneClass);
 290 extern mDNSu8 *putPrereqNameNotInUse(const domainname *const name, DNSMessage *msg, mDNSu8 *ptr, mDNSu8 *end);
 291 extern mDNSu8 *putDeletionRecord(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr);
 292 extern  mDNSu8 *putDeleteRRSet(DNSMessage *msg, mDNSu8 *ptr, const domainname *name, mDNSu16 rrtype);
 293 extern mDNSu8 *putDeleteAllRRSets(DNSMessage *msg, mDNSu8 *ptr, const domainname *name);
 294 extern mDNSu8 *putUpdateLease(DNSMessage *msg, mDNSu8 *end, mDNSu32 lease);
 295 #define PutResourceRecord(MSG, P, C, RR) PutResourceRecordTTL((MSG), (P), (C), (RR), (RR)->rroriginalttl)
 296
 297 extern mDNSu8 *putHINFO(const mDNS *const m, DNSMessage *const msg, mDNSu8 *end, DomainAuthInfo *authInfo);
 298
 299 // ***************************************************************************
 300 #if COMPILER_LIKES_PRAGMA_MARK
 301 #pragma mark -
 302 #pragma mark - DNS Message Parsing Functions
 303 #endif
 304
 305 #define HashSlot(X) (DomainNameHashValue(X) % CACHE_HASH_SLOTS)
 306 extern mDNSu32 DomainNameHashValue(const domainname *const name);
 307 extern void SetNewRData(ResourceRecord *const rr, RData *NewRData, mDNSu16 rdlength);
 308 extern const mDNSu8 *skipDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end);
 309 extern const mDNSu8 *getDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end,
 310         domainname *const name);
 311 extern const mDNSu8 *skipResourceRecord(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end);
 312 extern const mDNSu8 *GetLargeResourceRecord(mDNS *const m, const DNSMessage * const msg, const mDNSu8 *ptr,
 313     const mDNSu8 * end, const mDNSInterfaceID InterfaceID, mDNSu8 RecordType, LargeCacheRecord *largecr);
 314 extern const mDNSu8 *skipQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end);
 315 extern const mDNSu8 *getQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end, const mDNSInterfaceID InterfaceID,
 316         DNSQuestion *question);
 317 extern const mDNSu8 *LocateAnswers(const DNSMessage *const msg, const mDNSu8 *const end);
 318 extern const mDNSu8 *LocateAuthorities(const DNSMessage *const msg, const mDNSu8 *const end);
 319 extern const mDNSu8 *LocateAdditionals(const DNSMessage *const msg, const mDNSu8 *const end);
 320 extern const mDNSu8 *LocateLLQOptData(const DNSMessage *const msg, const mDNSu8 *const end);
 321 extern const rdataOPT *GetLLQOptData(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end);
 322 extern const mDNSu8 *LocateLeaseOptData(const DNSMessage *const msg, const mDNSu8 *const end);
 323 extern mDNSu32 GetPktLease(mDNS *m, DNSMessage *msg, const mDNSu8 *end);
 324 extern void DumpPacket(mDNS *const m, mDNSBool sent, char *type, const mDNSAddr *addr, mDNSIPPort port, const DNSMessage *const msg, const mDNSu8 *const end);
 325
 326 // ***************************************************************************
 327 #if COMPILER_LIKES_PRAGMA_MARK
 328 #pragma mark -
 329 #pragma mark - Packet Sending Functions
 330 #endif
 331
 332 extern mStatus mDNSSendDNSMessage(mDNS *const m, DNSMessage *const msg, mDNSu8 *end,
 333         mDNSInterfaceID InterfaceID, const mDNSAddr *dst, mDNSIPPort dstport, TCPSocket *sock, DomainAuthInfo *authInfo);
 334
 335 // ***************************************************************************
 336 #if COMPILER_LIKES_PRAGMA_MARK
 337 #pragma mark -
 338 #pragma mark - RR List Management & Task Management
 339 #endif
 340
 341 extern void mDNS_Lock_(mDNS *const m);
 342 extern void mDNS_Unlock_(mDNS *const m);
 343
 344 #define mDNS_Lock(X) do { \
 345         if ((X)->mDNS_busy != (X)->mDNS_reentrancy) LogMsg("%s: mDNS_Lock locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, (X)->mDNS_busy, (X)->mDNS_reentrancy); \
 346         mDNS_Lock_(X); } while (0)
 347
 348 #define mDNS_Unlock(X) do { mDNS_Unlock_(X); \
 349         if ((X)->mDNS_busy != (X)->mDNS_reentrancy) LogMsg("%s: mDNS_Unlock locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, (X)->mDNS_busy, (X)->mDNS_reentrancy); \
 350         } while (0)
 351
 352 #define mDNS_DropLockBeforeCallback() do { m->mDNS_reentrancy++; \
 353         if (m->mDNS_busy != m->mDNS_reentrancy) LogMsg("%s: Locking Failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, m->mDNS_busy, m->mDNS_reentrancy); \
 354         } while (0)
 355
 356 #define mDNS_ReclaimLockAfterCallback() do { \
 357         if (m->mDNS_busy != m->mDNS_reentrancy) LogMsg("%s: Unlocking Failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", __func__, m->mDNS_busy, m->mDNS_reentrancy); \
 358         m->mDNS_reentrancy--; } while (0)
 359
 360 #ifdef  __cplusplus
 361         }
 362 #endif
 363
 364 #endif // __DNSCOMMON_H_