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