1 /* -*- Mode: C; tab-width: 4 -*- 2 * 3 * Copyright (c) 2002-2013 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 // Set mDNS_InstantiateInlines to tell mDNSEmbeddedAPI.h to instantiate inline functions, if necessary 19 #define mDNS_InstantiateInlines 1 20 #include "DNSCommon.h" 21 #include "CryptoAlg.h" 22 #include "anonymous.h" 23 24 // Disable certain benign warnings with Microsoft compilers 25 #if (defined(_MSC_VER)) 26 // Disable "conditional expression is constant" warning for debug macros. 27 // Otherwise, this generates warnings for the perfectly natural construct "while(1)" 28 // If someone knows a variant way of writing "while(1)" that doesn't generate warning messages, please let us know 29 #pragma warning(disable:4127) 30 // Disable "array is too small to include a terminating null character" warning 31 // -- domain labels have an initial length byte, not a terminating null character 32 #pragma warning(disable:4295) 33 #endif 34 35 // *************************************************************************** 36 #if COMPILER_LIKES_PRAGMA_MARK 37 #pragma mark - Program Constants 38 #endif 39 40 mDNSexport const mDNSInterfaceID mDNSInterface_Any = 0; 41 mDNSexport const mDNSInterfaceID mDNSInterfaceMark = (mDNSInterfaceID)-1; 42 mDNSexport const mDNSInterfaceID mDNSInterface_LocalOnly = (mDNSInterfaceID)-2; 43 mDNSexport const mDNSInterfaceID mDNSInterface_Unicast = (mDNSInterfaceID)-3; 44 mDNSexport const mDNSInterfaceID mDNSInterface_P2P = (mDNSInterfaceID)-4; 45 mDNSexport const mDNSInterfaceID uDNSInterfaceMark = (mDNSInterfaceID)-5; 46 47 // Note: Microsoft's proposed "Link Local Multicast Name Resolution Protocol" (LLMNR) is essentially a limited version of 48 // Multicast DNS, using the same packet formats, naming syntax, and record types as Multicast DNS, but on a different UDP 49 // port and multicast address, which means it won't interoperate with the existing installed base of Multicast DNS responders. 50 // LLMNR uses IPv4 multicast address 224.0.0.252, IPv6 multicast address FF02::0001:0003, and UDP port 5355. 51 // Uncomment the appropriate lines below to build a special Multicast DNS responder for testing interoperability 52 // with Microsoft's LLMNR client code. 53 54 #define DiscardPortAsNumber 9 55 #define SSHPortAsNumber 22 56 #define UnicastDNSPortAsNumber 53 57 #define SSDPPortAsNumber 1900 58 #define IPSECPortAsNumber 4500 59 #define NSIPCPortAsNumber 5030 // Port used for dnsextd to talk to local nameserver bound to loopback 60 #define NATPMPAnnouncementPortAsNumber 5350 61 #define NATPMPPortAsNumber 5351 62 #define DNSEXTPortAsNumber 5352 // Port used for end-to-end DNS operations like LLQ, Updates with Leases, etc. 63 #define MulticastDNSPortAsNumber 5353 64 #define LoopbackIPCPortAsNumber 5354 65 //#define MulticastDNSPortAsNumber 5355 // LLMNR 66 #define PrivateDNSPortAsNumber 5533 67 68 mDNSexport const mDNSIPPort DiscardPort = { { DiscardPortAsNumber >> 8, DiscardPortAsNumber & 0xFF } }; 69 mDNSexport const mDNSIPPort SSHPort = { { SSHPortAsNumber >> 8, SSHPortAsNumber & 0xFF } }; 70 mDNSexport const mDNSIPPort UnicastDNSPort = { { UnicastDNSPortAsNumber >> 8, UnicastDNSPortAsNumber & 0xFF } }; 71 mDNSexport const mDNSIPPort SSDPPort = { { SSDPPortAsNumber >> 8, SSDPPortAsNumber & 0xFF } }; 72 mDNSexport const mDNSIPPort IPSECPort = { { IPSECPortAsNumber >> 8, IPSECPortAsNumber & 0xFF } }; 73 mDNSexport const mDNSIPPort NSIPCPort = { { NSIPCPortAsNumber >> 8, NSIPCPortAsNumber & 0xFF } }; 74 mDNSexport const mDNSIPPort NATPMPAnnouncementPort = { { NATPMPAnnouncementPortAsNumber >> 8, NATPMPAnnouncementPortAsNumber & 0xFF } }; 75 mDNSexport const mDNSIPPort NATPMPPort = { { NATPMPPortAsNumber >> 8, NATPMPPortAsNumber & 0xFF } }; 76 mDNSexport const mDNSIPPort DNSEXTPort = { { DNSEXTPortAsNumber >> 8, DNSEXTPortAsNumber & 0xFF } }; 77 mDNSexport const mDNSIPPort MulticastDNSPort = { { MulticastDNSPortAsNumber >> 8, MulticastDNSPortAsNumber & 0xFF } }; 78 mDNSexport const mDNSIPPort LoopbackIPCPort = { { LoopbackIPCPortAsNumber >> 8, LoopbackIPCPortAsNumber & 0xFF } }; 79 mDNSexport const mDNSIPPort PrivateDNSPort = { { PrivateDNSPortAsNumber >> 8, PrivateDNSPortAsNumber & 0xFF } }; 80 81 mDNSexport const OwnerOptData zeroOwner = { 0, 0, { { 0 } }, { { 0 } }, { { 0 } } }; 82 83 mDNSexport const mDNSIPPort zeroIPPort = { { 0 } }; 84 mDNSexport const mDNSv4Addr zerov4Addr = { { 0 } }; 85 mDNSexport const mDNSv6Addr zerov6Addr = { { 0 } }; 86 mDNSexport const mDNSEthAddr zeroEthAddr = { { 0 } }; 87 mDNSexport const mDNSv4Addr onesIPv4Addr = { { 255, 255, 255, 255 } }; 88 mDNSexport const mDNSv6Addr onesIPv6Addr = { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 } }; 89 mDNSexport const mDNSEthAddr onesEthAddr = { { 255, 255, 255, 255, 255, 255 } }; 90 mDNSexport const mDNSAddr zeroAddr = { mDNSAddrType_None, {{{ 0 }}} }; 91 92 mDNSexport const mDNSv4Addr AllDNSAdminGroup = { { 239, 255, 255, 251 } }; 93 mDNSexport const mDNSv4Addr AllHosts_v4 = { { 224, 0, 0, 1 } }; // For NAT-PMP & PCP Annoucements 94 mDNSexport const mDNSv6Addr AllHosts_v6 = { { 0xFF,0x02,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x01 } }; 95 mDNSexport const mDNSv6Addr NDP_prefix = { { 0xFF,0x02,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x01, 0xFF,0x00,0x00,0xFB } }; // FF02:0:0:0:0:1:FF00::/104 96 mDNSexport const mDNSEthAddr AllHosts_v6_Eth = { { 0x33, 0x33, 0x00, 0x00, 0x00, 0x01 } }; 97 mDNSexport const mDNSAddr AllDNSLinkGroup_v4 = { mDNSAddrType_IPv4, { { { 224, 0, 0, 251 } } } }; 98 //mDNSexport const mDNSAddr AllDNSLinkGroup_v4 = { mDNSAddrType_IPv4, { { { 224, 0, 0, 252 } } } }; // LLMNR 99 mDNSexport const mDNSAddr AllDNSLinkGroup_v6 = { mDNSAddrType_IPv6, { { { 0xFF,0x02,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0xFB } } } }; 100 //mDNSexport const mDNSAddr AllDNSLinkGroup_v6 = { mDNSAddrType_IPv6, { { { 0xFF,0x02,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x00,0x00,0x00, 0x00,0x01,0x00,0x03 } } } }; // LLMNR 101 102 mDNSexport const mDNSOpaque16 zeroID = { { 0, 0 } }; 103 mDNSexport const mDNSOpaque16 onesID = { { 255, 255 } }; 104 mDNSexport const mDNSOpaque16 QueryFlags = { { kDNSFlag0_QR_Query | kDNSFlag0_OP_StdQuery, 0 } }; 105 mDNSexport const mDNSOpaque16 uQueryFlags = { { kDNSFlag0_QR_Query | kDNSFlag0_OP_StdQuery | kDNSFlag0_RD, 0 } }; 106 mDNSexport const mDNSOpaque16 DNSSecQFlags = { { kDNSFlag0_QR_Query | kDNSFlag0_OP_StdQuery | kDNSFlag0_RD, kDNSFlag1_CD } }; 107 mDNSexport const mDNSOpaque16 ResponseFlags = { { kDNSFlag0_QR_Response | kDNSFlag0_OP_StdQuery | kDNSFlag0_AA, 0 } }; 108 mDNSexport const mDNSOpaque16 UpdateReqFlags = { { kDNSFlag0_QR_Query | kDNSFlag0_OP_Update, 0 } }; 109 mDNSexport const mDNSOpaque16 UpdateRespFlags = { { kDNSFlag0_QR_Response | kDNSFlag0_OP_Update, 0 } }; 110 111 mDNSexport const mDNSOpaque64 zeroOpaque64 = { { 0 } }; 112 113 // *************************************************************************** 114 #if COMPILER_LIKES_PRAGMA_MARK 115 #pragma mark - 116 #pragma mark - General Utility Functions 117 #endif 118 119 // return true for RFC1918 private addresses 120 mDNSexport mDNSBool mDNSv4AddrIsRFC1918(const mDNSv4Addr * const addr) 121 { 122 return ((addr->b[0] == 10) || // 10/8 prefix 123 (addr->b[0] == 172 && (addr->b[1] & 0xF0) == 16) || // 172.16/12 124 (addr->b[0] == 192 && addr->b[1] == 168)); // 192.168/16 125 } 126 127 mDNSexport void mDNSAddrMapIPv4toIPv6(mDNSv4Addr* in, mDNSv6Addr* out) 128 { 129 out->l[0] = 0; 130 out->l[1] = 0; 131 out->w[4] = 0; 132 out->w[5] = 0xffff; 133 out->b[12] = in->b[0]; 134 out->b[13] = in->b[1]; 135 out->b[14] = in->b[2]; 136 out->b[15] = in->b[3]; 137 } 138 139 mDNSexport mDNSBool mDNSAddrIPv4FromMappedIPv6(mDNSv6Addr *in, mDNSv4Addr* out) 140 { 141 if (in->l[0] != 0 || in->l[1] != 0 || in->w[4] != 0 || in->w[5] != 0xffff) 142 return mDNSfalse; 143 144 out->NotAnInteger = in->l[3]; 145 return mDNStrue; 146 } 147 148 mDNSexport NetworkInterfaceInfo *GetFirstActiveInterface(NetworkInterfaceInfo *intf) 149 { 150 while (intf && !intf->InterfaceActive) intf = intf->next; 151 return(intf); 152 } 153 154 mDNSexport mDNSInterfaceID GetNextActiveInterfaceID(const NetworkInterfaceInfo *intf) 155 { 156 const NetworkInterfaceInfo *next = GetFirstActiveInterface(intf->next); 157 if (next) return(next->InterfaceID);else return(mDNSNULL); 158 } 159 160 mDNSexport mDNSu32 NumCacheRecordsForInterfaceID(const mDNS *const m, mDNSInterfaceID id) 161 { 162 mDNSu32 slot, used = 0; 163 CacheGroup *cg; 164 const CacheRecord *rr; 165 FORALL_CACHERECORDS(slot, cg, rr) 166 { 167 if (rr->resrec.InterfaceID == id) 168 used++; 169 } 170 return(used); 171 } 172 173 mDNSexport char *DNSTypeName(mDNSu16 rrtype) 174 { 175 switch (rrtype) 176 { 177 case kDNSType_A: return("Addr"); 178 case kDNSType_NS: return("NS"); 179 case kDNSType_CNAME: return("CNAME"); 180 case kDNSType_SOA: return("SOA"); 181 case kDNSType_NULL: return("NULL"); 182 case kDNSType_PTR: return("PTR"); 183 case kDNSType_HINFO: return("HINFO"); 184 case kDNSType_TXT: return("TXT"); 185 case kDNSType_AAAA: return("AAAA"); 186 case kDNSType_SRV: return("SRV"); 187 case kDNSType_OPT: return("OPT"); 188 case kDNSType_NSEC: return("NSEC"); 189 case kDNSType_NSEC3: return("NSEC3"); 190 case kDNSType_NSEC3PARAM: return("NSEC3PARAM"); 191 case kDNSType_TSIG: return("TSIG"); 192 case kDNSType_RRSIG: return("RRSIG"); 193 case kDNSType_DNSKEY: return("DNSKEY"); 194 case kDNSType_DS: return("DS"); 195 case kDNSQType_ANY: return("ANY"); 196 default: { 197 static char buffer[16]; 198 mDNS_snprintf(buffer, sizeof(buffer), "TYPE%d", rrtype); 199 return(buffer); 200 } 201 } 202 } 203 204 mDNSlocal char *DNSSECAlgName(mDNSu8 alg) 205 { 206 switch (alg) 207 { 208 case CRYPTO_RSA_SHA1: return "RSA_SHA1"; 209 case CRYPTO_DSA_NSEC3_SHA1: return "DSA_NSEC3_SHA1"; 210 case CRYPTO_RSA_NSEC3_SHA1: return "RSA_NSEC3_SHA1"; 211 case CRYPTO_RSA_SHA256: return "RSA_SHA256"; 212 case CRYPTO_RSA_SHA512: return "RSA_SHA512"; 213 default: { 214 static char algbuffer[16]; 215 mDNS_snprintf(algbuffer, sizeof(algbuffer), "ALG%d", alg); 216 return(algbuffer); 217 } 218 } 219 } 220 221 mDNSlocal char *DNSSECDigestName(mDNSu8 digest) 222 { 223 switch (digest) 224 { 225 case SHA1_DIGEST_TYPE: return "SHA1"; 226 case SHA256_DIGEST_TYPE: return "SHA256"; 227 default: 228 { 229 static char digbuffer[16]; 230 mDNS_snprintf(digbuffer, sizeof(digbuffer), "DIG%d", digest); 231 return(digbuffer); 232 } 233 } 234 } 235 236 mDNSexport mDNSu32 swap32(mDNSu32 x) 237 { 238 mDNSu8 *ptr = (mDNSu8 *)&x; 239 return (mDNSu32)((mDNSu32)ptr[0] << 24 | (mDNSu32)ptr[1] << 16 | (mDNSu32)ptr[2] << 8 | ptr[3]); 240 } 241 242 mDNSexport mDNSu16 swap16(mDNSu16 x) 243 { 244 mDNSu8 *ptr = (mDNSu8 *)&x; 245 return (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); 246 } 247 248 // RFC 4034 Appendix B: Get the keyid of a DNS KEY. It is not transmitted 249 // explicitly on the wire. 250 // 251 // Note: This just helps narrow down the list of keys to look at. It is possible 252 // for two DNS keys to have the same ID i.e., key ID is not a unqiue tag. We ignore 253 // MD5 keys. 254 // 255 // 1st argument - the RDATA part of the DNSKEY RR 256 // 2nd argument - the RDLENGTH 257 // 258 mDNSlocal mDNSu32 keytag(mDNSu8 *key, mDNSu32 keysize) 259 { 260 unsigned long ac; 261 unsigned int i; 262 263 for (ac = 0, i = 0; i < keysize; ++i) 264 ac += (i & 1) ? key[i] : key[i] << 8; 265 ac += (ac >> 16) & 0xFFFF; 266 return ac & 0xFFFF; 267 } 268 269 mDNSexport int baseEncode(char *buffer, int blen, const mDNSu8 *data, int len, int encAlg) 270 { 271 AlgContext *ctx; 272 mDNSu8 *outputBuffer; 273 int length; 274 275 ctx = AlgCreate(ENC_ALG, encAlg); 276 if (!ctx) 277 { 278 LogMsg("baseEncode: AlgCreate failed\n"); 279 return 0; 280 } 281 AlgAdd(ctx, data, len); 282 outputBuffer = AlgEncode(ctx); 283 length = 0; 284 if (outputBuffer) 285 { 286 // Note: don't include any spaces in the format string below. This 287 // is also used by NSEC3 code for proving non-existence where it 288 // needs the base32 encoding without any spaces etc. 289 length = mDNS_snprintf(buffer, blen, "%s", outputBuffer); 290 } 291 AlgDestroy(ctx); 292 return length; 293 } 294 295 mDNSlocal void PrintTypeBitmap(const mDNSu8 *bmap, int bitmaplen, char *const buffer, mDNSu32 length) 296 { 297 int win, wlen, type; 298 299 while (bitmaplen > 0) 300 { 301 int i; 302 303 if (bitmaplen < 3) 304 { 305 LogMsg("PrintTypeBitmap: malformed bitmap, bitmaplen %d short", bitmaplen); 306 break; 307 } 308 309 win = *bmap++; 310 wlen = *bmap++; 311 bitmaplen -= 2; 312 if (bitmaplen < wlen || wlen < 1 || wlen > 32) 313 { 314 LogInfo("PrintTypeBitmap: malformed nsec, bitmaplen %d wlen %d", bitmaplen, wlen); 315 break; 316 } 317 if (win < 0 || win >= 256) 318 { 319 LogInfo("PrintTypeBitmap: malformed nsec, bad window win %d", win); 320 break; 321 } 322 type = win * 256; 323 for (i = 0; i < wlen * 8; i++) 324 { 325 if (bmap[i>>3] & (128 >> (i&7))) 326 length += mDNS_snprintf(buffer+length, (MaxMsg - 1) - length, "%s ", DNSTypeName(type + i)); 327 } 328 bmap += wlen; 329 bitmaplen -= wlen; 330 } 331 } 332 333 // Parse the fields beyond the base header. NSEC3 should have been validated. 334 mDNSexport void NSEC3Parse(const ResourceRecord *const rr, mDNSu8 **salt, int *hashLength, mDNSu8 **nxtName, int *bitmaplen, mDNSu8 **bitmap) 335 { 336 const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; 337 rdataNSEC3 *nsec3 = (rdataNSEC3 *)rdb->data; 338 mDNSu8 *p = (mDNSu8 *)&nsec3->salt; 339 int hlen; 340 341 if (salt) 342 { 343 if (nsec3->saltLength) 344 *salt = p; 345 else 346 *salt = mDNSNULL; 347 } 348 p += nsec3->saltLength; 349 // p is pointing at hashLength 350 hlen = (int)*p; 351 if (hashLength) 352 *hashLength = hlen; 353 p++; 354 if (nxtName) 355 *nxtName = p; 356 p += hlen; 357 if (bitmaplen) 358 *bitmaplen = rr->rdlength - (int)(p - rdb->data); 359 if (bitmap) 360 *bitmap = p; 361 } 362 363 // Note slight bug: this code uses the rdlength from the ResourceRecord object, to display 364 // the rdata from the RDataBody object. Sometimes this could be the wrong length -- but as 365 // long as this routine is only used for debugging messages, it probably isn't a big problem. 366 mDNSexport char *GetRRDisplayString_rdb(const ResourceRecord *const rr, const RDataBody *const rd1, char *const buffer) 367 { 368 const RDataBody2 *const rd = (RDataBody2 *)rd1; 369 #define RemSpc (MaxMsg-1-length) 370 char *ptr = buffer; 371 mDNSu32 length = mDNS_snprintf(buffer, MaxMsg-1, "%4d %##s %s ", rr->rdlength, rr->name->c, DNSTypeName(rr->rrtype)); 372 if (rr->RecordType == kDNSRecordTypePacketNegative) return(buffer); 373 if (!rr->rdlength && rr->rrtype != kDNSType_OPT) { mDNS_snprintf(buffer+length, RemSpc, "<< ZERO RDATA LENGTH >>"); return(buffer); } 374 375 switch (rr->rrtype) 376 { 377 case kDNSType_A: mDNS_snprintf(buffer+length, RemSpc, "%.4a", &rd->ipv4); break; 378 379 case kDNSType_NS: // Same as PTR 380 case kDNSType_CNAME: // Same as PTR 381 case kDNSType_PTR: mDNS_snprintf(buffer+length, RemSpc, "%##s", rd->name.c); break; 382 383 case kDNSType_SOA: mDNS_snprintf(buffer+length, RemSpc, "%##s %##s %d %d %d %d %d", 384 rd->soa.mname.c, rd->soa.rname.c, 385 rd->soa.serial, rd->soa.refresh, rd->soa.retry, rd->soa.expire, rd->soa.min); 386 break; 387 388 case kDNSType_HINFO: // Display this the same as TXT (show all constituent strings) 389 case kDNSType_TXT: { 390 const mDNSu8 *t = rd->txt.c; 391 while (t < rd->txt.c + rr->rdlength) 392 { 393 length += mDNS_snprintf(buffer+length, RemSpc, "%s%#s", t > rd->txt.c ? "¦" : "", t); 394 t += 1 + t[0]; 395 } 396 } break; 397 398 case kDNSType_AAAA: mDNS_snprintf(buffer+length, RemSpc, "%.16a", &rd->ipv6); break; 399 case kDNSType_SRV: mDNS_snprintf(buffer+length, RemSpc, "%u %u %u %##s", 400 rd->srv.priority, rd->srv.weight, mDNSVal16(rd->srv.port), rd->srv.target.c); break; 401 402 case kDNSType_OPT: { 403 const rdataOPT *opt; 404 const rdataOPT *const end = (const rdataOPT *)&rd->data[rr->rdlength]; 405 length += mDNS_snprintf(buffer+length, RemSpc, "Max %d", rr->rrclass); 406 for (opt = &rd->opt[0]; opt < end; opt++) 407 { 408 switch(opt->opt) 409 { 410 case kDNSOpt_LLQ: 411 length += mDNS_snprintf(buffer+length, RemSpc, " LLQ"); 412 length += mDNS_snprintf(buffer+length, RemSpc, " Vers %d", opt->u.llq.vers); 413 length += mDNS_snprintf(buffer+length, RemSpc, " Op %d", opt->u.llq.llqOp); 414 length += mDNS_snprintf(buffer+length, RemSpc, " Err/Port %d", opt->u.llq.err); 415 length += mDNS_snprintf(buffer+length, RemSpc, " ID %08X%08X", opt->u.llq.id.l[0], opt->u.llq.id.l[1]); 416 length += mDNS_snprintf(buffer+length, RemSpc, " Lease %d", opt->u.llq.llqlease); 417 break; 418 case kDNSOpt_Lease: 419 length += mDNS_snprintf(buffer+length, RemSpc, " Lease %d", opt->u.updatelease); 420 break; 421 case kDNSOpt_Owner: 422 length += mDNS_snprintf(buffer+length, RemSpc, " Owner"); 423 length += mDNS_snprintf(buffer+length, RemSpc, " Vers %d", opt->u.owner.vers); 424 length += mDNS_snprintf(buffer+length, RemSpc, " Seq %3d", (mDNSu8)opt->u.owner.seq); // Display as unsigned 425 length += mDNS_snprintf(buffer+length, RemSpc, " MAC %.6a", opt->u.owner.HMAC.b); 426 if (opt->optlen >= DNSOpt_OwnerData_ID_Wake_Space-4) 427 { 428 length += mDNS_snprintf(buffer+length, RemSpc, " I-MAC %.6a", opt->u.owner.IMAC.b); 429 if (opt->optlen > DNSOpt_OwnerData_ID_Wake_Space-4) 430 length += mDNS_snprintf(buffer+length, RemSpc, " Password %.6a", opt->u.owner.password.b); 431 } 432 break; 433 case kDNSOpt_Trace: 434 length += mDNS_snprintf(buffer+length, RemSpc, " Trace"); 435 length += mDNS_snprintf(buffer+length, RemSpc, " Platform %d", opt->u.tracer.platf); 436 length += mDNS_snprintf(buffer+length, RemSpc, " mDNSVers %d", opt->u.tracer.mDNSv); 437 break; 438 default: 439 length += mDNS_snprintf(buffer+length, RemSpc, " Unknown %d", opt->opt); 440 break; 441 } 442 } 443 } 444 break; 445 446 case kDNSType_NSEC: { 447 domainname *next = (domainname *)rd->data; 448 int len, bitmaplen; 449 mDNSu8 *bmap; 450 len = DomainNameLength(next); 451 bitmaplen = rr->rdlength - len; 452 bmap = (mDNSu8 *)((mDNSu8 *)next + len); 453 454 if (UNICAST_NSEC(rr)) 455 length += mDNS_snprintf(buffer+length, RemSpc, "%##s ", next->c); 456 PrintTypeBitmap(bmap, bitmaplen, buffer, length); 457 458 } 459 break; 460 case kDNSType_NSEC3: { 461 rdataNSEC3 *nsec3 = (rdataNSEC3 *)rd->data; 462 const mDNSu8 *p = (mDNSu8 *)&nsec3->salt; 463 int hashLength, bitmaplen, i; 464 465 length += mDNS_snprintf(buffer+length, RemSpc, "\t%s %d %d ", 466 DNSSECDigestName(nsec3->alg), nsec3->flags, swap16(nsec3->iterations)); 467 468 if (!nsec3->saltLength) 469 { 470 length += mDNS_snprintf(buffer+length, RemSpc, "-"); 471 } 472 else 473 { 474 for (i = 0; i < nsec3->saltLength; i++) 475 { 476 length += mDNS_snprintf(buffer+length, RemSpc, "%x", p[i]); 477 } 478 } 479 480 // put a space at the end 481 length += mDNS_snprintf(buffer+length, RemSpc, " "); 482 483 p += nsec3->saltLength; 484 // p is pointing at hashLength 485 hashLength = (int)*p++; 486 487 length += baseEncode(buffer + length, RemSpc, p, hashLength, ENC_BASE32); 488 489 // put a space at the end 490 length += mDNS_snprintf(buffer+length, RemSpc, " "); 491 492 p += hashLength; 493 bitmaplen = rr->rdlength - (int)(p - rd->data); 494 PrintTypeBitmap(p, bitmaplen, buffer, length); 495 } 496 break; 497 case kDNSType_RRSIG: { 498 rdataRRSig *rrsig = (rdataRRSig *)rd->data; 499 mDNSu8 expTimeBuf[64]; 500 mDNSu8 inceptTimeBuf[64]; 501 unsigned long inceptClock; 502 unsigned long expClock; 503 int len; 504 505 expClock = (unsigned long)swap32(rrsig->sigExpireTime); 506 mDNSPlatformFormatTime(expClock, expTimeBuf, sizeof(expTimeBuf)); 507 508 inceptClock = (unsigned long)swap32(rrsig->sigInceptTime); 509 mDNSPlatformFormatTime(inceptClock, inceptTimeBuf, sizeof(inceptTimeBuf)); 510 511 length += mDNS_snprintf(buffer+length, RemSpc, "\t%s %s %d %d %s %s %d %##s ", 512 DNSTypeName(swap16(rrsig->typeCovered)), DNSSECAlgName(rrsig->alg), rrsig->labels, swap32(rrsig->origTTL), 513 expTimeBuf, inceptTimeBuf, swap16(rrsig->keyTag), ((domainname *)(&rrsig->signerName))->c); 514 515 len = DomainNameLength((domainname *)&rrsig->signerName); 516 length += baseEncode(buffer + length, RemSpc, (const mDNSu8 *)(rd->data + len + RRSIG_FIXED_SIZE), 517 rr->rdlength - (len + RRSIG_FIXED_SIZE), ENC_BASE64); 518 } 519 break; 520 case kDNSType_DNSKEY: { 521 rdataDNSKey *rrkey = (rdataDNSKey *)rd->data; 522 length += mDNS_snprintf(buffer+length, RemSpc, "\t%d %d %s %u ", swap16(rrkey->flags), rrkey->proto, 523 DNSSECAlgName(rrkey->alg), (unsigned int)keytag((mDNSu8 *)rrkey, rr->rdlength)); 524 length += baseEncode(buffer + length, RemSpc, (const mDNSu8 *)(rd->data + DNSKEY_FIXED_SIZE), 525 rr->rdlength - DNSKEY_FIXED_SIZE, ENC_BASE64); 526 } 527 break; 528 case kDNSType_DS: { 529 mDNSu8 *p; 530 int i; 531 rdataDS *rrds = (rdataDS *)rd->data; 532 533 length += mDNS_snprintf(buffer+length, RemSpc, "\t%s\t%d\t%s ", DNSSECAlgName(rrds->alg), swap16(rrds->keyTag), 534 DNSSECDigestName(rrds->digestType)); 535 536 p = (mDNSu8 *)(rd->data + DS_FIXED_SIZE); 537 for (i = 0; i < (rr->rdlength - DS_FIXED_SIZE); i++) 538 { 539 length += mDNS_snprintf(buffer+length, RemSpc, "%x", p[i]); 540 } 541 } 542 break; 543 544 default: mDNS_snprintf(buffer+length, RemSpc, "RDLen %d: %s", rr->rdlength, rd->data); 545 // Really should scan buffer to check if text is valid UTF-8 and only replace with dots if not 546 for (ptr = buffer; *ptr; ptr++) if (*ptr < ' ') *ptr = '.'; 547 break; 548 } 549 return(buffer); 550 } 551 552 // See comments in mDNSEmbeddedAPI.h 553 #if _PLATFORM_HAS_STRONG_PRNG_ 554 #define mDNSRandomNumber mDNSPlatformRandomNumber 555 #else 556 mDNSlocal mDNSu32 mDNSRandomFromSeed(mDNSu32 seed) 557 { 558 return seed * 21 + 1; 559 } 560 561 mDNSlocal mDNSu32 mDNSMixRandomSeed(mDNSu32 seed, mDNSu8 iteration) 562 { 563 return iteration ? mDNSMixRandomSeed(mDNSRandomFromSeed(seed), --iteration) : seed; 564 } 565 566 mDNSlocal mDNSu32 mDNSRandomNumber() 567 { 568 static mDNSBool seeded = mDNSfalse; 569 static mDNSu32 seed = 0; 570 if (!seeded) 571 { 572 seed = mDNSMixRandomSeed(mDNSPlatformRandomSeed(), 100); 573 seeded = mDNStrue; 574 } 575 return (seed = mDNSRandomFromSeed(seed)); 576 } 577 #endif // ! _PLATFORM_HAS_STRONG_PRNG_ 578 579 mDNSexport mDNSu32 mDNSRandom(mDNSu32 max) // Returns pseudo-random result from zero to max inclusive 580 { 581 mDNSu32 ret = 0; 582 mDNSu32 mask = 1; 583 584 while (mask < max) mask = (mask << 1) | 1; 585 586 do ret = mDNSRandomNumber() & mask; 587 while (ret > max); 588 589 return ret; 590 } 591 592 mDNSexport mDNSBool mDNSSameAddress(const mDNSAddr *ip1, const mDNSAddr *ip2) 593 { 594 if (ip1->type == ip2->type) 595 { 596 switch (ip1->type) 597 { 598 case mDNSAddrType_None: return(mDNStrue); // Empty addresses have no data and are therefore always equal 599 case mDNSAddrType_IPv4: return (mDNSBool)(mDNSSameIPv4Address(ip1->ip.v4, ip2->ip.v4)); 600 case mDNSAddrType_IPv6: return (mDNSBool)(mDNSSameIPv6Address(ip1->ip.v6, ip2->ip.v6)); 601 } 602 } 603 return(mDNSfalse); 604 } 605 606 mDNSexport mDNSBool mDNSAddrIsDNSMulticast(const mDNSAddr *ip) 607 { 608 switch(ip->type) 609 { 610 case mDNSAddrType_IPv4: return (mDNSBool)(mDNSSameIPv4Address(ip->ip.v4, AllDNSLinkGroup_v4.ip.v4)); 611 case mDNSAddrType_IPv6: return (mDNSBool)(mDNSSameIPv6Address(ip->ip.v6, AllDNSLinkGroup_v6.ip.v6)); 612 default: return(mDNSfalse); 613 } 614 } 615 616 // *************************************************************************** 617 #if COMPILER_LIKES_PRAGMA_MARK 618 #pragma mark - 619 #pragma mark - Domain Name Utility Functions 620 #endif 621 622 mDNSexport mDNSBool SameDomainLabel(const mDNSu8 *a, const mDNSu8 *b) 623 { 624 int i; 625 const int len = *a++; 626 627 if (len > MAX_DOMAIN_LABEL) 628 { debugf("Malformed label (too long)"); return(mDNSfalse); } 629 630 if (len != *b++) return(mDNSfalse); 631 for (i=0; i<len; i++) 632 { 633 mDNSu8 ac = *a++; 634 mDNSu8 bc = *b++; 635 if (mDNSIsUpperCase(ac)) ac += 'a' - 'A'; 636 if (mDNSIsUpperCase(bc)) bc += 'a' - 'A'; 637 if (ac != bc) return(mDNSfalse); 638 } 639 return(mDNStrue); 640 } 641 642 mDNSexport mDNSBool SameDomainName(const domainname *const d1, const domainname *const d2) 643 { 644 const mDNSu8 * a = d1->c; 645 const mDNSu8 * b = d2->c; 646 const mDNSu8 *const max = d1->c + MAX_DOMAIN_NAME; // Maximum that's valid 647 648 while (*a || *b) 649 { 650 if (a + 1 + *a >= max) 651 { debugf("Malformed domain name (more than 256 characters)"); return(mDNSfalse); } 652 if (!SameDomainLabel(a, b)) return(mDNSfalse); 653 a += 1 + *a; 654 b += 1 + *b; 655 } 656 657 return(mDNStrue); 658 } 659 660 mDNSexport mDNSBool SameDomainNameCS(const domainname *const d1, const domainname *const d2) 661 { 662 mDNSu16 l1 = DomainNameLength(d1); 663 mDNSu16 l2 = DomainNameLength(d2); 664 return(l1 <= MAX_DOMAIN_NAME && l1 == l2 && mDNSPlatformMemSame(d1, d2, l1)); 665 } 666 667 mDNSexport mDNSBool IsLocalDomain(const domainname *d) 668 { 669 // Domains that are defined to be resolved via link-local multicast are: 670 // local., 254.169.in-addr.arpa., and {8,9,A,B}.E.F.ip6.arpa. 671 static const domainname *nL = (const domainname*)"\x5" "local"; 672 static const domainname *nR = (const domainname*)"\x3" "254" "\x3" "169" "\x7" "in-addr" "\x4" "arpa"; 673 static const domainname *n8 = (const domainname*)"\x1" "8" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa"; 674 static const domainname *n9 = (const domainname*)"\x1" "9" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa"; 675 static const domainname *nA = (const domainname*)"\x1" "a" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa"; 676 static const domainname *nB = (const domainname*)"\x1" "b" "\x1" "e" "\x1" "f" "\x3" "ip6" "\x4" "arpa"; 677 678 const domainname *d1, *d2, *d3, *d4, *d5; // Top-level domain, second-level domain, etc. 679 d1 = d2 = d3 = d4 = d5 = mDNSNULL; 680 while (d->c[0]) 681 { 682 d5 = d4; d4 = d3; d3 = d2; d2 = d1; d1 = d; 683 d = (const domainname*)(d->c + 1 + d->c[0]); 684 } 685 686 if (d1 && SameDomainName(d1, nL)) return(mDNStrue); 687 if (d4 && SameDomainName(d4, nR)) return(mDNStrue); 688 if (d5 && SameDomainName(d5, n8)) return(mDNStrue); 689 if (d5 && SameDomainName(d5, n9)) return(mDNStrue); 690 if (d5 && SameDomainName(d5, nA)) return(mDNStrue); 691 if (d5 && SameDomainName(d5, nB)) return(mDNStrue); 692 return(mDNSfalse); 693 } 694 695 mDNSexport const mDNSu8 *LastLabel(const domainname *d) 696 { 697 const mDNSu8 *p = d->c; 698 while (d->c[0]) 699 { 700 p = d->c; 701 d = (const domainname*)(d->c + 1 + d->c[0]); 702 } 703 return(p); 704 } 705 706 // Returns length of a domain name INCLUDING the byte for the final null label 707 // e.g. for the root label "." it returns one 708 // For the FQDN "com." it returns 5 (length byte, three data bytes, final zero) 709 // Legal results are 1 (just root label) to 256 (MAX_DOMAIN_NAME) 710 // If the given domainname is invalid, result is 257 (MAX_DOMAIN_NAME+1) 711 mDNSexport mDNSu16 DomainNameLengthLimit(const domainname *const name, const mDNSu8 *limit) 712 { 713 const mDNSu8 *src = name->c; 714 while (src < limit && *src <= MAX_DOMAIN_LABEL) 715 { 716 if (*src == 0) return((mDNSu16)(src - name->c + 1)); 717 src += 1 + *src; 718 } 719 return(MAX_DOMAIN_NAME+1); 720 } 721 722 // CompressedDomainNameLength returns the length of a domain name INCLUDING the byte 723 // for the final null label, e.g. for the root label "." it returns one. 724 // E.g. for the FQDN "foo.com." it returns 9 725 // (length, three data bytes, length, three more data bytes, final zero). 726 // In the case where a parent domain name is provided, and the given name is a child 727 // of that parent, CompressedDomainNameLength returns the length of the prefix portion 728 // of the child name, plus TWO bytes for the compression pointer. 729 // E.g. for the name "foo.com." with parent "com.", it returns 6 730 // (length, three data bytes, two-byte compression pointer). 731 mDNSexport mDNSu16 CompressedDomainNameLength(const domainname *const name, const domainname *parent) 732 { 733 const mDNSu8 *src = name->c; 734 if (parent && parent->c[0] == 0) parent = mDNSNULL; 735 while (*src) 736 { 737 if (*src > MAX_DOMAIN_LABEL) return(MAX_DOMAIN_NAME+1); 738 if (parent && SameDomainName((const domainname *)src, parent)) return((mDNSu16)(src - name->c + 2)); 739 src += 1 + *src; 740 if (src - name->c >= MAX_DOMAIN_NAME) return(MAX_DOMAIN_NAME+1); 741 } 742 return((mDNSu16)(src - name->c + 1)); 743 } 744 745 // CountLabels() returns number of labels in name, excluding final root label 746 // (e.g. for "apple.com." CountLabels returns 2.) 747 mDNSexport int CountLabels(const domainname *d) 748 { 749 int count = 0; 750 const mDNSu8 *ptr; 751 for (ptr = d->c; *ptr; ptr = ptr + ptr[0] + 1) count++; 752 return count; 753 } 754 755 // SkipLeadingLabels skips over the first 'skip' labels in the domainname, 756 // returning a pointer to the suffix with 'skip' labels removed. 757 mDNSexport const domainname *SkipLeadingLabels(const domainname *d, int skip) 758 { 759 while (skip > 0 && d->c[0]) { d = (const domainname *)(d->c + 1 + d->c[0]); skip--; } 760 return(d); 761 } 762 763 // AppendLiteralLabelString appends a single label to an existing (possibly empty) domainname. 764 // The C string contains the label as-is, with no escaping, etc. 765 // Any dots in the name are literal dots, not label separators 766 // If successful, AppendLiteralLabelString returns a pointer to the next unused byte 767 // in the domainname bufer (i.e. the next byte after the terminating zero). 768 // If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes) 769 // AppendLiteralLabelString returns mDNSNULL. 770 mDNSexport mDNSu8 *AppendLiteralLabelString(domainname *const name, const char *cstr) 771 { 772 mDNSu8 * ptr = name->c + DomainNameLength(name) - 1; // Find end of current name 773 const mDNSu8 *const lim1 = name->c + MAX_DOMAIN_NAME - 1; // Limit of how much we can add (not counting final zero) 774 const mDNSu8 *const lim2 = ptr + 1 + MAX_DOMAIN_LABEL; 775 const mDNSu8 *const lim = (lim1 < lim2) ? lim1 : lim2; 776 mDNSu8 *lengthbyte = ptr++; // Record where the length is going to go 777 778 while (*cstr && ptr < lim) *ptr++ = (mDNSu8)*cstr++; // Copy the data 779 *lengthbyte = (mDNSu8)(ptr - lengthbyte - 1); // Fill in the length byte 780 *ptr++ = 0; // Put the null root label on the end 781 if (*cstr) return(mDNSNULL); // Failure: We didn't successfully consume all input 782 else return(ptr); // Success: return new value of ptr 783 } 784 785 // AppendDNSNameString appends zero or more labels to an existing (possibly empty) domainname. 786 // The C string is in conventional DNS syntax: 787 // Textual labels, escaped as necessary using the usual DNS '\' notation, separated by dots. 788 // If successful, AppendDNSNameString returns a pointer to the next unused byte 789 // in the domainname bufer (i.e. the next byte after the terminating zero). 790 // If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes) 791 // AppendDNSNameString returns mDNSNULL. 792 mDNSexport mDNSu8 *AppendDNSNameString(domainname *const name, const char *cstring) 793 { 794 const char *cstr = cstring; 795 mDNSu8 * ptr = name->c + DomainNameLength(name) - 1; // Find end of current name 796 const mDNSu8 *const lim = name->c + MAX_DOMAIN_NAME - 1; // Limit of how much we can add (not counting final zero) 797 while (*cstr && ptr < lim) // While more characters, and space to put them... 798 { 799 mDNSu8 *lengthbyte = ptr++; // Record where the length is going to go 800 if (*cstr == '.') { LogMsg("AppendDNSNameString: Illegal empty label in name \"%s\"", cstring); return(mDNSNULL); } 801 while (*cstr && *cstr != '.' && ptr < lim) // While we have characters in the label... 802 { 803 mDNSu8 c = (mDNSu8)*cstr++; // Read the character 804 if (c == '\\') // If escape character, check next character 805 { 806 c = (mDNSu8)*cstr++; // Assume we'll just take the next character 807 if (mDNSIsDigit(cstr[-1]) && mDNSIsDigit(cstr[0]) && mDNSIsDigit(cstr[1])) 808 { // If three decimal digits, 809 int v0 = cstr[-1] - '0'; // then interpret as three-digit decimal 810 int v1 = cstr[ 0] - '0'; 811 int v2 = cstr[ 1] - '0'; 812 int val = v0 * 100 + v1 * 10 + v2; 813 if (val <= 255) { c = (mDNSu8)val; cstr += 2; } // If valid three-digit decimal value, use it 814 } 815 } 816 *ptr++ = c; // Write the character 817 } 818 if (*cstr) cstr++; // Skip over the trailing dot (if present) 819 if (ptr - lengthbyte - 1 > MAX_DOMAIN_LABEL) // If illegal label, abort 820 return(mDNSNULL); 821 *lengthbyte = (mDNSu8)(ptr - lengthbyte - 1); // Fill in the length byte 822 } 823 824 *ptr++ = 0; // Put the null root label on the end 825 if (*cstr) return(mDNSNULL); // Failure: We didn't successfully consume all input 826 else return(ptr); // Success: return new value of ptr 827 } 828 829 // AppendDomainLabel appends a single label to a name. 830 // If successful, AppendDomainLabel returns a pointer to the next unused byte 831 // in the domainname bufer (i.e. the next byte after the terminating zero). 832 // If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes) 833 // AppendDomainLabel returns mDNSNULL. 834 mDNSexport mDNSu8 *AppendDomainLabel(domainname *const name, const domainlabel *const label) 835 { 836 int i; 837 mDNSu8 *ptr = name->c + DomainNameLength(name) - 1; 838 839 // Check label is legal 840 if (label->c[0] > MAX_DOMAIN_LABEL) return(mDNSNULL); 841 842 // Check that ptr + length byte + data bytes + final zero does not exceed our limit 843 if (ptr + 1 + label->c[0] + 1 > name->c + MAX_DOMAIN_NAME) return(mDNSNULL); 844 845 for (i=0; i<=label->c[0]; i++) *ptr++ = label->c[i]; // Copy the label data 846 *ptr++ = 0; // Put the null root label on the end 847 return(ptr); 848 } 849 850 mDNSexport mDNSu8 *AppendDomainName(domainname *const name, const domainname *const append) 851 { 852 mDNSu8 * ptr = name->c + DomainNameLength(name) - 1; // Find end of current name 853 const mDNSu8 *const lim = name->c + MAX_DOMAIN_NAME - 1; // Limit of how much we can add (not counting final zero) 854 const mDNSu8 * src = append->c; 855 while (src[0]) 856 { 857 int i; 858 if (ptr + 1 + src[0] > lim) return(mDNSNULL); 859 for (i=0; i<=src[0]; i++) *ptr++ = src[i]; 860 *ptr = 0; // Put the null root label on the end 861 src += i; 862 } 863 return(ptr); 864 } 865 866 // MakeDomainLabelFromLiteralString makes a single domain label from a single literal C string (with no escaping). 867 // If successful, MakeDomainLabelFromLiteralString returns mDNStrue. 868 // If unable to convert the whole string to a legal domain label (i.e. because length is more than 63 bytes) then 869 // MakeDomainLabelFromLiteralString makes a legal domain label from the first 63 bytes of the string and returns mDNSfalse. 870 // In some cases silently truncated oversized names to 63 bytes is acceptable, so the return result may be ignored. 871 // In other cases silent truncation may not be acceptable, so in those cases the calling function needs to check the return result. 872 mDNSexport mDNSBool MakeDomainLabelFromLiteralString(domainlabel *const label, const char *cstr) 873 { 874 mDNSu8 * ptr = label->c + 1; // Where we're putting it 875 const mDNSu8 *const limit = label->c + 1 + MAX_DOMAIN_LABEL; // The maximum we can put 876 while (*cstr && ptr < limit) *ptr++ = (mDNSu8)*cstr++; // Copy the label 877 label->c[0] = (mDNSu8)(ptr - label->c - 1); // Set the length byte 878 return(*cstr == 0); // Return mDNStrue if we successfully consumed all input 879 } 880 881 // MakeDomainNameFromDNSNameString makes a native DNS-format domainname from a C string. 882 // The C string is in conventional DNS syntax: 883 // Textual labels, escaped as necessary using the usual DNS '\' notation, separated by dots. 884 // If successful, MakeDomainNameFromDNSNameString returns a pointer to the next unused byte 885 // in the domainname bufer (i.e. the next byte after the terminating zero). 886 // If unable to construct a legal domain name (i.e. label more than 63 bytes, or total more than 256 bytes) 887 // MakeDomainNameFromDNSNameString returns mDNSNULL. 888 mDNSexport mDNSu8 *MakeDomainNameFromDNSNameString(domainname *const name, const char *cstr) 889 { 890 name->c[0] = 0; // Make an empty domain name 891 return(AppendDNSNameString(name, cstr)); // And then add this string to it 892 } 893 894 mDNSexport char *ConvertDomainLabelToCString_withescape(const domainlabel *const label, char *ptr, char esc) 895 { 896 const mDNSu8 * src = label->c; // Domain label we're reading 897 const mDNSu8 len = *src++; // Read length of this (non-null) label 898 const mDNSu8 *const end = src + len; // Work out where the label ends 899 if (len > MAX_DOMAIN_LABEL) return(mDNSNULL); // If illegal label, abort 900 while (src < end) // While we have characters in the label 901 { 902 mDNSu8 c = *src++; 903 if (esc) 904 { 905 if (c == '.' || c == esc) // If character is a dot or the escape character 906 *ptr++ = esc; // Output escape character 907 else if (c <= ' ') // If non-printing ascii, 908 { // Output decimal escape sequence 909 *ptr++ = esc; 910 *ptr++ = (char) ('0' + (c / 100) ); 911 *ptr++ = (char) ('0' + (c / 10) % 10); 912 c = (mDNSu8)('0' + (c ) % 10); 913 } 914 } 915 *ptr++ = (char)c; // Copy the character 916 } 917 *ptr = 0; // Null-terminate the string 918 return(ptr); // and return 919 } 920 921 // Note: To guarantee that there will be no possible overrun, cstr must be at least MAX_ESCAPED_DOMAIN_NAME (1009 bytes) 922 mDNSexport char *ConvertDomainNameToCString_withescape(const domainname *const name, char *ptr, char esc) 923 { 924 const mDNSu8 *src = name->c; // Domain name we're reading 925 const mDNSu8 *const max = name->c + MAX_DOMAIN_NAME; // Maximum that's valid 926 927 if (*src == 0) *ptr++ = '.'; // Special case: For root, just write a dot 928 929 while (*src) // While more characters in the domain name 930 { 931 if (src + 1 + *src >= max) return(mDNSNULL); 932 ptr = ConvertDomainLabelToCString_withescape((const domainlabel *)src, ptr, esc); 933 if (!ptr) return(mDNSNULL); 934 src += 1 + *src; 935 *ptr++ = '.'; // Write the dot after the label 936 } 937 938 *ptr++ = 0; // Null-terminate the string 939 return(ptr); // and return 940 } 941 942 // RFC 1034 rules: 943 // Host names must start with a letter, end with a letter or digit, 944 // and have as interior characters only letters, digits, and hyphen. 945 // This was subsequently modified in RFC 1123 to allow the first character to be either a letter or a digit 946 947 mDNSexport void ConvertUTF8PstringToRFC1034HostLabel(const mDNSu8 UTF8Name[], domainlabel *const hostlabel) 948 { 949 const mDNSu8 * src = &UTF8Name[1]; 950 const mDNSu8 *const end = &UTF8Name[1] + UTF8Name[0]; 951 mDNSu8 * ptr = &hostlabel->c[1]; 952 const mDNSu8 *const lim = &hostlabel->c[1] + MAX_DOMAIN_LABEL; 953 while (src < end) 954 { 955 // Delete apostrophes from source name 956 if (src[0] == '\'') { src++; continue; } // Standard straight single quote 957 if (src + 2 < end && src[0] == 0xE2 && src[1] == 0x80 && src[2] == 0x99) 958 { src += 3; continue; } // Unicode curly apostrophe 959 if (ptr < lim) 960 { 961 if (mDNSValidHostChar(*src, (ptr > &hostlabel->c[1]), (src < end-1))) *ptr++ = *src; 962 else if (ptr > &hostlabel->c[1] && ptr[-1] != '-') *ptr++ = '-'; 963 } 964 src++; 965 } 966 while (ptr > &hostlabel->c[1] && ptr[-1] == '-') ptr--; // Truncate trailing '-' marks 967 hostlabel->c[0] = (mDNSu8)(ptr - &hostlabel->c[1]); 968 } 969 970 #define ValidTransportProtocol(X) ( (X)[0] == 4 && (X)[1] == '_' && \ 971 ((((X)[2] | 0x20) == 'u' && ((X)[3] | 0x20) == 'd') || (((X)[2] | 0x20) == 't' && ((X)[3] | 0x20) == 'c')) && \ 972 ((X)[4] | 0x20) == 'p') 973 974 mDNSexport mDNSu8 *ConstructServiceName(domainname *const fqdn, 975 const domainlabel *name, const domainname *type, const domainname *const domain) 976 { 977 int i, len; 978 mDNSu8 *dst = fqdn->c; 979 const mDNSu8 *src; 980 const char *errormsg; 981 #if APPLE_OSX_mDNSResponder 982 mDNSBool loggedUnderscore = mDNSfalse; 983 static char typeBuf[MAX_ESCAPED_DOMAIN_NAME]; 984 #endif 985 986 // In the case where there is no name (and ONLY in that case), 987 // a single-label subtype is allowed as the first label of a three-part "type" 988 if (!name && type) 989 { 990 const mDNSu8 *s0 = type->c; 991 if (s0[0] && s0[0] < 0x40) // If legal first label (at least one character, and no more than 63) 992 { 993 const mDNSu8 * s1 = s0 + 1 + s0[0]; 994 if (s1[0] && s1[0] < 0x40) // and legal second label (at least one character, and no more than 63) 995 { 996 const mDNSu8 *s2 = s1 + 1 + s1[0]; 997 if (s2[0] && s2[0] < 0x40 && s2[1+s2[0]] == 0) // and we have three and only three labels 998 { 999 static const mDNSu8 SubTypeLabel[5] = mDNSSubTypeLabel; 1000 src = s0; // Copy the first label 1001 len = *src; 1002 for (i=0; i <= len; i++) *dst++ = *src++; 1003 for (i=0; i < (int)sizeof(SubTypeLabel); i++) *dst++ = SubTypeLabel[i]; 1004 type = (const domainname *)s1; 1005 1006 // Special support to enable the DNSServiceBrowse call made by Bonjour Browser 1007 // For these queries, we retract the "._sub" we just added between the subtype and the main type 1008 // Remove after Bonjour Browser is updated to use DNSServiceQueryRecord instead of DNSServiceBrowse 1009 if (SameDomainName((domainname*)s0, (const domainname*)"\x09_services\x07_dns-sd\x04_udp")) 1010 dst -= sizeof(SubTypeLabel); 1011 } 1012 } 1013 } 1014 } 1015 1016 if (name && name->c[0]) 1017 { 1018 src = name->c; // Put the service name into the domain name 1019 len = *src; 1020 if (len >= 0x40) { errormsg = "Service instance name too long"; goto fail; } 1021 for (i=0; i<=len; i++) *dst++ = *src++; 1022 } 1023 else 1024 name = (domainlabel*)""; // Set this up to be non-null, to avoid errors if we have to call LogMsg() below 1025 1026 src = type->c; // Put the service type into the domain name 1027 len = *src; 1028 if (len < 2 || len > 16) 1029 { 1030 LogMsg("Bad service type in %#s.%##s%##s Application protocol name must be underscore plus 1-15 characters. " 1031 "See <http://www.dns-sd.org/ServiceTypes.html>", name->c, type->c, domain->c); 1032 #if APPLE_OSX_mDNSResponder 1033 ConvertDomainNameToCString(type, typeBuf); 1034 mDNSASLLog(mDNSNULL, "serviceType.nameTooLong", "noop", typeBuf, ""); 1035 #endif 1036 } 1037 if (len < 2 || len >= 0x40 || (len > 16 && !SameDomainName(domain, &localdomain))) return(mDNSNULL); 1038 if (src[1] != '_') { errormsg = "Application protocol name must begin with underscore"; goto fail; } 1039 for (i=2; i<=len; i++) 1040 { 1041 // Letters and digits are allowed anywhere 1042 if (mDNSIsLetter(src[i]) || mDNSIsDigit(src[i])) continue; 1043 // Hyphens are only allowed as interior characters 1044 // Underscores are not supposed to be allowed at all, but for backwards compatibility with some old products we do allow them, 1045 // with the same rule as hyphens 1046 if ((src[i] == '-' || src[i] == '_') && i > 2 && i < len) 1047 { 1048 #if APPLE_OSX_mDNSResponder 1049 if (src[i] == '_' && loggedUnderscore == mDNSfalse) 1050 { 1051 ConvertDomainNameToCString(type, typeBuf); 1052 mDNSASLLog(mDNSNULL, "serviceType.nameWithUnderscore", "noop", typeBuf, ""); 1053 loggedUnderscore = mDNStrue; 1054 } 1055 #endif 1056 continue; 1057 } 1058 errormsg = "Application protocol name must contain only letters, digits, and hyphens"; 1059 #if APPLE_OSX_mDNSResponder 1060 { 1061 ConvertDomainNameToCString(type, typeBuf); 1062 mDNSASLLog(mDNSNULL, "serviceType.nameWithIllegalCharacters", "noop", typeBuf, ""); 1063 } 1064 #endif 1065 goto fail; 1066 } 1067 for (i=0; i<=len; i++) *dst++ = *src++; 1068 1069 len = *src; 1070 if (!ValidTransportProtocol(src)) { errormsg = "Transport protocol name must be _udp or _tcp"; goto fail; } 1071 for (i=0; i<=len; i++) *dst++ = *src++; 1072 1073 if (*src) { errormsg = "Service type must have only two labels"; goto fail; } 1074 1075 *dst = 0; 1076 if (!domain->c[0]) { errormsg = "Service domain must be non-empty"; goto fail; } 1077 if (SameDomainName(domain, (const domainname*)"\x05" "local" "\x04" "arpa")) 1078 { errormsg = "Illegal domain \"local.arpa.\" Use \"local.\" (or empty string)"; goto fail; } 1079 dst = AppendDomainName(fqdn, domain); 1080 if (!dst) { errormsg = "Service domain too long"; goto fail; } 1081 return(dst); 1082 1083 fail: 1084 LogMsg("ConstructServiceName: %s: %#s.%##s%##s", errormsg, name->c, type->c, domain->c); 1085 return(mDNSNULL); 1086 } 1087 1088 // A service name has the form: instance.application-protocol.transport-protocol.domain 1089 // DeconstructServiceName is currently fairly forgiving: It doesn't try to enforce character 1090 // set or length limits for the protocol names, and the final domain is allowed to be empty. 1091 // However, if the given FQDN doesn't contain at least three labels, 1092 // DeconstructServiceName will reject it and return mDNSfalse. 1093 mDNSexport mDNSBool DeconstructServiceName(const domainname *const fqdn, 1094 domainlabel *const name, domainname *const type, domainname *const domain) 1095 { 1096 int i, len; 1097 const mDNSu8 *src = fqdn->c; 1098 const mDNSu8 *max = fqdn->c + MAX_DOMAIN_NAME; 1099 mDNSu8 *dst; 1100 1101 dst = name->c; // Extract the service name 1102 len = *src; 1103 if (!len) { debugf("DeconstructServiceName: FQDN empty!"); return(mDNSfalse); } 1104 if (len >= 0x40) { debugf("DeconstructServiceName: Instance name too long"); return(mDNSfalse); } 1105 for (i=0; i<=len; i++) *dst++ = *src++; 1106 1107 dst = type->c; // Extract the service type 1108 len = *src; 1109 if (!len) { debugf("DeconstructServiceName: FQDN contains only one label!"); return(mDNSfalse); } 1110 if (len >= 0x40) { debugf("DeconstructServiceName: Application protocol name too long"); return(mDNSfalse); } 1111 if (src[1] != '_') { debugf("DeconstructServiceName: No _ at start of application protocol"); return(mDNSfalse); } 1112 for (i=0; i<=len; i++) *dst++ = *src++; 1113 1114 len = *src; 1115 if (!len) { debugf("DeconstructServiceName: FQDN contains only two labels!"); return(mDNSfalse); } 1116 if (!ValidTransportProtocol(src)) 1117 { debugf("DeconstructServiceName: Transport protocol must be _udp or _tcp"); return(mDNSfalse); } 1118 for (i=0; i<=len; i++) *dst++ = *src++; 1119 *dst++ = 0; // Put terminator on the end of service type 1120 1121 dst = domain->c; // Extract the service domain 1122 while (*src) 1123 { 1124 len = *src; 1125 if (len >= 0x40) 1126 { debugf("DeconstructServiceName: Label in service domain too long"); return(mDNSfalse); } 1127 if (src + 1 + len + 1 >= max) 1128 { debugf("DeconstructServiceName: Total service domain too long"); return(mDNSfalse); } 1129 for (i=0; i<=len; i++) *dst++ = *src++; 1130 } 1131 *dst++ = 0; // Put the null root label on the end 1132 1133 return(mDNStrue); 1134 } 1135 1136 mDNSexport mStatus DNSNameToLowerCase(domainname *d, domainname *result) 1137 { 1138 const mDNSu8 *a = d->c; 1139 mDNSu8 *b = result->c; 1140 const mDNSu8 *const max = d->c + MAX_DOMAIN_NAME; 1141 int i, len; 1142 1143 while (*a) 1144 { 1145 if (a + 1 + *a >= max) 1146 { 1147 LogMsg("DNSNameToLowerCase: ERROR!! Malformed Domain name"); 1148 return mStatus_BadParamErr; 1149 } 1150 len = *a++; 1151 *b++ = len; 1152 for (i = 0; i < len; i++) 1153 { 1154 mDNSu8 ac = *a++; 1155 if (mDNSIsUpperCase(ac)) ac += 'a' - 'A'; 1156 *b++ = ac; 1157 } 1158 } 1159 *b = 0; 1160 1161 return mStatus_NoError; 1162 } 1163 1164 mDNSexport const mDNSu8 *NSEC3HashName(const domainname *name, rdataNSEC3 *nsec3, const mDNSu8 *AnonData, int AnonDataLen, 1165 const mDNSu8 hash[NSEC3_MAX_HASH_LEN], int *dlen) 1166 { 1167 AlgContext *ctx; 1168 int i; 1169 domainname lname; 1170 mDNSu8 *p = (mDNSu8 *)&nsec3->salt; 1171 const mDNSu8 *digest; 1172 int digestlen; 1173 mDNSBool first = mDNStrue; 1174 1175 if (DNSNameToLowerCase((domainname *)name, &lname) != mStatus_NoError) 1176 { 1177 LogMsg("NSEC3HashName: ERROR!! DNSNameToLowerCase failed"); 1178 return mDNSNULL; 1179 } 1180 1181 digest = lname.c; 1182 digestlen = DomainNameLength(&lname); 1183 1184 // Note that it is "i <=". The first iteration is for digesting the name and salt. 1185 // The iteration count does not include that. 1186 for (i = 0; i <= swap16(nsec3->iterations); i++) 1187 { 1188 ctx = AlgCreate(DIGEST_ALG, nsec3->alg); 1189 if (!ctx) 1190 { 1191 LogMsg("NSEC3HashName: ERROR!! Cannot allocate context"); 1192 return mDNSNULL; 1193 } 1194 1195 AlgAdd(ctx, digest, digestlen); 1196 if (nsec3->saltLength) 1197 AlgAdd(ctx, p, nsec3->saltLength); 1198 if (AnonDataLen) 1199 AlgAdd(ctx, AnonData, AnonDataLen); 1200 if (first) 1201 { 1202 first = mDNSfalse; 1203 digest = hash; 1204 digestlen = AlgLength(ctx); 1205 } 1206 AlgFinal(ctx, (void *)digest, digestlen); 1207 AlgDestroy(ctx); 1208 } 1209 *dlen = digestlen; 1210 return digest; 1211 } 1212 1213 // Notes on UTF-8: 1214 // 0xxxxxxx represents a 7-bit ASCII value from 0x00 to 0x7F 1215 // 10xxxxxx is a continuation byte of a multi-byte character 1216 // 110xxxxx is the first byte of a 2-byte character (11 effective bits; values 0x 80 - 0x 800-1) 1217 // 1110xxxx is the first byte of a 3-byte character (16 effective bits; values 0x 800 - 0x 10000-1) 1218 // 11110xxx is the first byte of a 4-byte character (21 effective bits; values 0x 10000 - 0x 200000-1) 1219 // 111110xx is the first byte of a 5-byte character (26 effective bits; values 0x 200000 - 0x 4000000-1) 1220 // 1111110x is the first byte of a 6-byte character (31 effective bits; values 0x4000000 - 0x80000000-1) 1221 // 1222 // UTF-16 surrogate pairs are used in UTF-16 to encode values larger than 0xFFFF. 1223 // Although UTF-16 surrogate pairs are not supposed to appear in legal UTF-8, we want to be defensive 1224 // about that too. (See <http://www.unicode.org/faq/utf_bom.html#34>, "What are surrogates?") 1225 // The first of pair is a UTF-16 value in the range 0xD800-0xDBFF (11101101 1010xxxx 10xxxxxx in UTF-8), 1226 // and the second is a UTF-16 value in the range 0xDC00-0xDFFF (11101101 1011xxxx 10xxxxxx in UTF-8). 1227 1228 mDNSexport mDNSu32 TruncateUTF8ToLength(mDNSu8 *string, mDNSu32 length, mDNSu32 max) 1229 { 1230 if (length > max) 1231 { 1232 mDNSu8 c1 = string[max]; // First byte after cut point 1233 mDNSu8 c2 = (max+1 < length) ? string[max+1] : (mDNSu8)0xB0; // Second byte after cut point 1234 length = max; // Trim length down 1235 while (length > 0) 1236 { 1237 // Check if the byte right after the chop point is a UTF-8 continuation byte, 1238 // or if the character right after the chop point is the second of a UTF-16 surrogate pair. 1239 // If so, then we continue to chop more bytes until we get to a legal chop point. 1240 mDNSBool continuation = ((c1 & 0xC0) == 0x80); 1241 mDNSBool secondsurrogate = (c1 == 0xED && (c2 & 0xF0) == 0xB0); 1242 if (!continuation && !secondsurrogate) break; 1243 c2 = c1; 1244 c1 = string[--length]; 1245 } 1246 // Having truncated characters off the end of our string, also cut off any residual white space 1247 while (length > 0 && string[length-1] <= ' ') length--; 1248 } 1249 return(length); 1250 } 1251 1252 // Returns true if a rich text label ends in " (nnn)", or if an RFC 1034 1253 // name ends in "-nnn", where n is some decimal number. 1254 mDNSexport mDNSBool LabelContainsSuffix(const domainlabel *const name, const mDNSBool RichText) 1255 { 1256 mDNSu16 l = name->c[0]; 1257 1258 if (RichText) 1259 { 1260 if (l < 4) return mDNSfalse; // Need at least " (2)" 1261 if (name->c[l--] != ')') return mDNSfalse; // Last char must be ')' 1262 if (!mDNSIsDigit(name->c[l])) return mDNSfalse; // Preceeded by a digit 1263 l--; 1264 while (l > 2 && mDNSIsDigit(name->c[l])) l--; // Strip off digits 1265 return (name->c[l] == '(' && name->c[l - 1] == ' '); 1266 } 1267 else 1268 { 1269 if (l < 2) return mDNSfalse; // Need at least "-2" 1270 if (!mDNSIsDigit(name->c[l])) return mDNSfalse; // Last char must be a digit 1271 l--; 1272 while (l > 2 && mDNSIsDigit(name->c[l])) l--; // Strip off digits 1273 return (name->c[l] == '-'); 1274 } 1275 } 1276 1277 // removes an auto-generated suffix (appended on a name collision) from a label. caller is 1278 // responsible for ensuring that the label does indeed contain a suffix. returns the number 1279 // from the suffix that was removed. 1280 mDNSexport mDNSu32 RemoveLabelSuffix(domainlabel *name, mDNSBool RichText) 1281 { 1282 mDNSu32 val = 0, multiplier = 1; 1283 1284 // Chop closing parentheses from RichText suffix 1285 if (RichText && name->c[0] >= 1 && name->c[name->c[0]] == ')') name->c[0]--; 1286 1287 // Get any existing numerical suffix off the name 1288 while (mDNSIsDigit(name->c[name->c[0]])) 1289 { val += (name->c[name->c[0]] - '0') * multiplier; multiplier *= 10; name->c[0]--; } 1290 1291 // Chop opening parentheses or dash from suffix 1292 if (RichText) 1293 { 1294 if (name->c[0] >= 2 && name->c[name->c[0]] == '(' && name->c[name->c[0]-1] == ' ') name->c[0] -= 2; 1295 } 1296 else 1297 { 1298 if (name->c[0] >= 1 && name->c[name->c[0]] == '-') name->c[0] -= 1; 1299 } 1300 1301 return(val); 1302 } 1303 1304 // appends a numerical suffix to a label, with the number following a whitespace and enclosed 1305 // in parentheses (rich text) or following two consecutive hyphens (RFC 1034 domain label). 1306 mDNSexport void AppendLabelSuffix(domainlabel *const name, mDNSu32 val, const mDNSBool RichText) 1307 { 1308 mDNSu32 divisor = 1, chars = 2; // Shortest possible RFC1034 name suffix is 2 characters ("-2") 1309 if (RichText) chars = 4; // Shortest possible RichText suffix is 4 characters (" (2)") 1310 1311 // Truncate trailing spaces from RichText names 1312 if (RichText) while (name->c[name->c[0]] == ' ') name->c[0]--; 1313 1314 while (divisor < 0xFFFFFFFFUL/10 && val >= divisor * 10) { divisor *= 10; chars++; } 1315 1316 name->c[0] = (mDNSu8) TruncateUTF8ToLength(name->c+1, name->c[0], MAX_DOMAIN_LABEL - chars); 1317 1318 if (RichText) { name->c[++name->c[0]] = ' '; name->c[++name->c[0]] = '('; } 1319 else { name->c[++name->c[0]] = '-'; } 1320 1321 while (divisor) 1322 { 1323 name->c[++name->c[0]] = (mDNSu8)('0' + val / divisor); 1324 val %= divisor; 1325 divisor /= 10; 1326 } 1327 1328 if (RichText) name->c[++name->c[0]] = ')'; 1329 } 1330 1331 mDNSexport void IncrementLabelSuffix(domainlabel *name, mDNSBool RichText) 1332 { 1333 mDNSu32 val = 0; 1334 1335 if (LabelContainsSuffix(name, RichText)) 1336 val = RemoveLabelSuffix(name, RichText); 1337 1338 // If no existing suffix, start by renaming "Foo" as "Foo (2)" or "Foo-2" as appropriate. 1339 // If existing suffix in the range 2-9, increment it. 1340 // If we've had ten conflicts already, there are probably too many hosts trying to use the same name, 1341 // so add a random increment to improve the chances of finding an available name next time. 1342 if (val == 0) val = 2; 1343 else if (val < 10) val++; 1344 else val += 1 + mDNSRandom(99); 1345 1346 AppendLabelSuffix(name, val, RichText); 1347 } 1348 1349 // *************************************************************************** 1350 #if COMPILER_LIKES_PRAGMA_MARK 1351 #pragma mark - 1352 #pragma mark - Resource Record Utility Functions 1353 #endif 1354 1355 // Set up a AuthRecord with sensible default values. 1356 // These defaults may be overwritten with new values before mDNS_Register is called 1357 mDNSexport void mDNS_SetupResourceRecord(AuthRecord *rr, RData *RDataStorage, mDNSInterfaceID InterfaceID, 1358 mDNSu16 rrtype, mDNSu32 ttl, mDNSu8 RecordType, AuthRecType artype, mDNSRecordCallback Callback, void *Context) 1359 { 1360 // 1361 // LocalOnly auth record can be created with LocalOnly InterfaceID or a valid InterfaceID. 1362 // Most of the applications normally create with LocalOnly InterfaceID and we store them as 1363 // such, so that we can deliver the response to questions that specify LocalOnly InterfaceID. 1364 // LocalOnly resource records can also be created with valid InterfaceID which happens today 1365 // when we create LocalOnly records for /etc/hosts. 1366 1367 if (InterfaceID == mDNSInterface_LocalOnly && artype != AuthRecordLocalOnly) 1368 { 1369 LogMsg("mDNS_SetupResourceRecord: ERROR!! Mismatch LocalOnly record InterfaceID %p called with artype %d", InterfaceID, artype); 1370 return; 1371 } 1372 else if (InterfaceID == mDNSInterface_P2P && artype != AuthRecordP2P) 1373 { 1374 LogMsg("mDNS_SetupResourceRecord: ERROR!! Mismatch P2P record InterfaceID %p called with artype %d", InterfaceID, artype); 1375 return; 1376 } 1377 else if (!InterfaceID && (artype == AuthRecordP2P || artype == AuthRecordLocalOnly)) 1378 { 1379 LogMsg("mDNS_SetupResourceRecord: ERROR!! Mismatch InterfaceAny record InterfaceID %p called with artype %d", InterfaceID, artype); 1380 return; 1381 } 1382 1383 // Don't try to store a TTL bigger than we can represent in platform time units 1384 if (ttl > 0x7FFFFFFFUL / mDNSPlatformOneSecond) 1385 ttl = 0x7FFFFFFFUL / mDNSPlatformOneSecond; 1386 else if (ttl == 0) // And Zero TTL is illegal 1387 ttl = DefaultTTLforRRType(rrtype); 1388 1389 // Field Group 1: The actual information pertaining to this resource record 1390 rr->resrec.RecordType = RecordType; 1391 rr->resrec.InterfaceID = InterfaceID; 1392 rr->resrec.name = &rr->namestorage; 1393 rr->resrec.rrtype = rrtype; 1394 rr->resrec.rrclass = kDNSClass_IN; 1395 rr->resrec.rroriginalttl = ttl; 1396 rr->resrec.rDNSServer = mDNSNULL; 1397 rr->resrec.AnonInfo = mDNSNULL; 1398 // rr->resrec.rdlength = MUST set by client and/or in mDNS_Register_internal 1399 // rr->resrec.rdestimate = set in mDNS_Register_internal 1400 // rr->resrec.rdata = MUST be set by client 1401 1402 if (RDataStorage) 1403 rr->resrec.rdata = RDataStorage; 1404 else 1405 { 1406 rr->resrec.rdata = &rr->rdatastorage; 1407 rr->resrec.rdata->MaxRDLength = sizeof(RDataBody); 1408 } 1409 1410 // Field Group 2: Persistent metadata for Authoritative Records 1411 rr->Additional1 = mDNSNULL; 1412 rr->Additional2 = mDNSNULL; 1413 rr->DependentOn = mDNSNULL; 1414 rr->RRSet = mDNSNULL; 1415 rr->RecordCallback = Callback; 1416 rr->RecordContext = Context; 1417 1418 rr->AutoTarget = Target_Manual; 1419 rr->AllowRemoteQuery = mDNSfalse; 1420 rr->ForceMCast = mDNSfalse; 1421 1422 rr->WakeUp = zeroOwner; 1423 rr->AddressProxy = zeroAddr; 1424 rr->TimeRcvd = 0; 1425 rr->TimeExpire = 0; 1426 rr->ARType = artype; 1427 rr->AuthFlags = 0; 1428 1429 // Field Group 3: Transient state for Authoritative Records (set in mDNS_Register_internal) 1430 // Field Group 4: Transient uDNS state for Authoritative Records (set in mDNS_Register_internal) 1431 1432 // For now, until the uDNS code is fully integrated, it's helpful to zero the uDNS state fields here too, just in case 1433 // (e.g. uDNS_RegisterService short-circuits the usual mDNS_Register_internal record registration calls, so a bunch 1434 // of fields don't get set up properly. In particular, if we don't zero rr->QueuedRData then the uDNS code crashes.) 1435 rr->state = regState_Zero; 1436 rr->uselease = 0; 1437 rr->expire = 0; 1438 rr->Private = 0; 1439 rr->updateid = zeroID; 1440 rr->zone = rr->resrec.name; 1441 rr->nta = mDNSNULL; 1442 rr->tcp = mDNSNULL; 1443 rr->OrigRData = 0; 1444 rr->OrigRDLen = 0; 1445 rr->InFlightRData = 0; 1446 rr->InFlightRDLen = 0; 1447 rr->QueuedRData = 0; 1448 rr->QueuedRDLen = 0; 1449 mDNSPlatformMemZero(&rr->NATinfo, sizeof(rr->NATinfo)); 1450 rr->SRVChanged = mDNSfalse; 1451 rr->mState = mergeState_Zero; 1452 1453 rr->namestorage.c[0] = 0; // MUST be set by client before calling mDNS_Register() 1454 } 1455 1456 mDNSexport void mDNS_SetupQuestion(DNSQuestion *const q, const mDNSInterfaceID InterfaceID, const domainname *const name, 1457 const mDNSu16 qtype, mDNSQuestionCallback *const callback, void *const context) 1458 { 1459 q->InterfaceID = InterfaceID; 1460 q->flags = 0; 1461 q->Target = zeroAddr; 1462 AssignDomainName(&q->qname, name); 1463 q->qtype = qtype; 1464 q->qclass = kDNSClass_IN; 1465 q->LongLived = (qtype == kDNSType_PTR); 1466 q->ExpectUnique = (qtype != kDNSType_PTR); 1467 q->ForceMCast = mDNSfalse; 1468 q->ReturnIntermed = mDNSfalse; 1469 q->SuppressUnusable = mDNSfalse; 1470 q->DenyOnCellInterface = mDNSfalse; 1471 q->DenyOnExpInterface = mDNSfalse; 1472 q->SearchListIndex = 0; 1473 q->AppendSearchDomains = 0; 1474 q->RetryWithSearchDomains = mDNSfalse; 1475 q->TimeoutQuestion = 0; 1476 q->WakeOnResolve = 0; 1477 q->UseBackgroundTrafficClass = mDNSfalse; 1478 q->ValidationRequired = 0; 1479 q->ValidatingResponse = 0; 1480 q->ProxyQuestion = 0; 1481 q->qnameOrig = mDNSNULL; 1482 q->AnonInfo = mDNSNULL; 1483 q->pid = mDNSPlatformGetPID(); 1484 q->DisallowPID = mDNSfalse; 1485 q->ServiceID = -1; 1486 q->QuestionCallback = callback; 1487 q->QuestionContext = context; 1488 } 1489 1490 mDNSexport mDNSu32 RDataHashValue(const ResourceRecord *const rr) 1491 { 1492 int len = rr->rdlength; 1493 const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; 1494 const mDNSu8 *ptr = rdb->data; 1495 mDNSu32 sum = 0; 1496 1497 switch(rr->rrtype) 1498 { 1499 case kDNSType_NS: 1500 case kDNSType_MD: 1501 case kDNSType_MF: 1502 case kDNSType_CNAME: 1503 case kDNSType_MB: 1504 case kDNSType_MG: 1505 case kDNSType_MR: 1506 case kDNSType_PTR: 1507 case kDNSType_NSAP_PTR: 1508 case kDNSType_DNAME: return DomainNameHashValue(&rdb->name); 1509 1510 case kDNSType_SOA: return rdb->soa.serial + 1511 rdb->soa.refresh + 1512 rdb->soa.retry + 1513 rdb->soa.expire + 1514 rdb->soa.min + 1515 DomainNameHashValue(&rdb->soa.mname) + 1516 DomainNameHashValue(&rdb->soa.rname); 1517 1518 case kDNSType_MX: 1519 case kDNSType_AFSDB: 1520 case kDNSType_RT: 1521 case kDNSType_KX: return DomainNameHashValue(&rdb->mx.exchange); 1522 1523 case kDNSType_MINFO: 1524 case kDNSType_RP: return DomainNameHashValue(&rdb->rp.mbox) + DomainNameHashValue(&rdb->rp.txt); 1525 1526 case kDNSType_PX: return DomainNameHashValue(&rdb->px.map822) + DomainNameHashValue(&rdb->px.mapx400); 1527 1528 case kDNSType_SRV: return DomainNameHashValue(&rdb->srv.target); 1529 1530 case kDNSType_OPT: return 0; // OPT is a pseudo-RR container structure; makes no sense to compare 1531 1532 case kDNSType_NSEC: { 1533 int dlen; 1534 dlen = DomainNameLength((domainname *)rdb->data); 1535 sum = DomainNameHashValue((domainname *)rdb->data); 1536 ptr += dlen; 1537 len -= dlen; 1538 /* FALLTHROUGH */ 1539 } 1540 1541 default: 1542 { 1543 int i; 1544 for (i=0; i+1 < len; i+=2) 1545 { 1546 sum += (((mDNSu32)(ptr[i])) << 8) | ptr[i+1]; 1547 sum = (sum<<3) | (sum>>29); 1548 } 1549 if (i < len) 1550 { 1551 sum += ((mDNSu32)(ptr[i])) << 8; 1552 } 1553 return(sum); 1554 } 1555 } 1556 } 1557 1558 // r1 has to be a full ResourceRecord including rrtype and rdlength 1559 // r2 is just a bare RDataBody, which MUST be the same rrtype and rdlength as r1 1560 mDNSexport mDNSBool SameRDataBody(const ResourceRecord *const r1, const RDataBody *const r2, DomainNameComparisonFn *samename) 1561 { 1562 const RDataBody2 *const b1 = (RDataBody2 *)r1->rdata->u.data; 1563 const RDataBody2 *const b2 = (RDataBody2 *)r2; 1564 switch(r1->rrtype) 1565 { 1566 case kDNSType_NS: 1567 case kDNSType_MD: 1568 case kDNSType_MF: 1569 case kDNSType_CNAME: 1570 case kDNSType_MB: 1571 case kDNSType_MG: 1572 case kDNSType_MR: 1573 case kDNSType_PTR: 1574 case kDNSType_NSAP_PTR: 1575 case kDNSType_DNAME: return(SameDomainName(&b1->name, &b2->name)); 1576 1577 case kDNSType_SOA: return (mDNSBool)( b1->soa.serial == b2->soa.serial && 1578 b1->soa.refresh == b2->soa.refresh && 1579 b1->soa.retry == b2->soa.retry && 1580 b1->soa.expire == b2->soa.expire && 1581 b1->soa.min == b2->soa.min && 1582 samename(&b1->soa.mname, &b2->soa.mname) && 1583 samename(&b1->soa.rname, &b2->soa.rname)); 1584 1585 case kDNSType_MX: 1586 case kDNSType_AFSDB: 1587 case kDNSType_RT: 1588 case kDNSType_KX: return (mDNSBool)( b1->mx.preference == b2->mx.preference && 1589 samename(&b1->mx.exchange, &b2->mx.exchange)); 1590 1591 case kDNSType_MINFO: 1592 case kDNSType_RP: return (mDNSBool)( samename(&b1->rp.mbox, &b2->rp.mbox) && 1593 samename(&b1->rp.txt, &b2->rp.txt)); 1594 1595 case kDNSType_PX: return (mDNSBool)( b1->px.preference == b2->px.preference && 1596 samename(&b1->px.map822, &b2->px.map822) && 1597 samename(&b1->px.mapx400, &b2->px.mapx400)); 1598 1599 case kDNSType_SRV: return (mDNSBool)( b1->srv.priority == b2->srv.priority && 1600 b1->srv.weight == b2->srv.weight && 1601 mDNSSameIPPort(b1->srv.port, b2->srv.port) && 1602 samename(&b1->srv.target, &b2->srv.target)); 1603 1604 case kDNSType_OPT: return mDNSfalse; // OPT is a pseudo-RR container structure; makes no sense to compare 1605 case kDNSType_NSEC: { 1606 // If the "nxt" name changes in case, we want to delete the old 1607 // and store just the new one. If the caller passes in SameDomainCS for "samename", 1608 // we would return "false" when the only change between the two rdata is the case 1609 // change in "nxt". 1610 // 1611 // Note: rdlength of both the RData are same (ensured by the caller) and hence we can 1612 // use just r1->rdlength below 1613 1614 int dlen1 = DomainNameLength((domainname *)b1->data); 1615 int dlen2 = DomainNameLength((domainname *)b2->data); 1616 return (mDNSBool)(dlen1 == dlen2 && 1617 samename((domainname *)b1->data, (domainname *)b2->data) && 1618 mDNSPlatformMemSame(b1->data + dlen1, b2->data + dlen2, r1->rdlength - dlen1)); 1619 } 1620 1621 default: return(mDNSPlatformMemSame(b1->data, b2->data, r1->rdlength)); 1622 } 1623 } 1624 1625 mDNSexport mDNSBool BitmapTypeCheck(mDNSu8 *bmap, int bitmaplen, mDNSu16 type) 1626 { 1627 int win, wlen; 1628 int wintype; 1629 1630 // The window that this type belongs to. NSEC has 256 windows that 1631 // comprises of 256 types. 1632 wintype = type >> 8; 1633 1634 while (bitmaplen > 0) 1635 { 1636 if (bitmaplen < 3) 1637 { 1638 LogInfo("BitmapTypeCheck: malformed nsec, bitmaplen %d short", bitmaplen); 1639 return mDNSfalse; 1640 } 1641 1642 win = *bmap++; 1643 wlen = *bmap++; 1644 bitmaplen -= 2; 1645 if (bitmaplen < wlen || wlen < 1 || wlen > 32) 1646 { 1647 LogInfo("BitmapTypeCheck: malformed nsec, bitmaplen %d wlen %d, win %d", bitmaplen, wlen, win); 1648 return mDNSfalse; 1649 } 1650 if (win < 0 || win >= 256) 1651 { 1652 LogInfo("BitmapTypeCheck: malformed nsec, wlen %d", wlen); 1653 return mDNSfalse; 1654 } 1655 if (win == wintype) 1656 { 1657 // First byte in the window serves 0 to 7, the next one serves 8 to 15 and so on. 1658 // Calculate the right byte offset first. 1659 int boff = (type & 0xff ) >> 3; 1660 if (wlen <= boff) 1661 return mDNSfalse; 1662 // The last three bits values 0 to 7 corresponds to bit positions 1663 // within the byte. 1664 return (bmap[boff] & (0x80 >> (type & 7))); 1665 } 1666 else 1667 { 1668 // If the windows are ordered, then we could check to see 1669 // if wintype > win and then return early. 1670 bmap += wlen; 1671 bitmaplen -= wlen; 1672 } 1673 } 1674 return mDNSfalse; 1675 } 1676 1677 // Don't call this function if the resource record is not NSEC. It will return false 1678 // which means that the type does not exist. 1679 mDNSexport mDNSBool RRAssertsExistence(const ResourceRecord *const rr, mDNSu16 type) 1680 { 1681 const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; 1682 mDNSu8 *nsec = (mDNSu8 *)rdb->data; 1683 int len, bitmaplen; 1684 mDNSu8 *bmap; 1685 1686 if (rr->rrtype != kDNSType_NSEC) return mDNSfalse; 1687 1688 len = DomainNameLength((domainname *)nsec); 1689 1690 bitmaplen = rr->rdlength - len; 1691 bmap = nsec + len; 1692 return (BitmapTypeCheck(bmap, bitmaplen, type)); 1693 } 1694 1695 // Don't call this function if the resource record is not NSEC. It will return false 1696 // which means that the type exists. 1697 mDNSexport mDNSBool RRAssertsNonexistence(const ResourceRecord *const rr, mDNSu16 type) 1698 { 1699 if (rr->rrtype != kDNSType_NSEC) return mDNSfalse; 1700 1701 return !RRAssertsExistence(rr, type); 1702 } 1703 1704 // Checks whether the RRSIG or NSEC record answers the question "q". 1705 mDNSlocal mDNSBool DNSSECRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q, mDNSBool *checkType) 1706 { 1707 *checkType = mDNStrue; 1708 1709 // This function is called for all questions and as long as the type matches, 1710 // return true. For the types (RRSIG and NSEC) that are specifically checked in 1711 // this function, returning true still holds good. 1712 if (q->qtype == rr->rrtype) 1713 return mDNStrue; 1714 1715 // For DS and DNSKEY questions, the types should match i.e., don't answer using CNAME 1716 // records as it answers any question type. 1717 // 1718 // - DS record comes from the parent zone where CNAME record cannot coexist and hence 1719 // cannot possibly answer it. 1720 // 1721 // - For DNSKEY, one could potentially follow CNAME but there could be a DNSKEY at 1722 // the "qname" itself. To keep it simple, we don't follow CNAME. 1723 1724 if ((q->qtype == kDNSType_DS || q->qtype == kDNSType_DNSKEY) && (q->qtype != rr->rrtype)) 1725 { 1726 debugf("DNSSECRecordAnswersQuestion: %d type resource record matched question %##s (%s), ignoring", rr->rrtype, 1727 q->qname.c, DNSTypeName(q->qtype)); 1728 return mDNSfalse; 1729 } 1730 1731 // If we are validating a response using DNSSEC, we might already have the records 1732 // for the "q->qtype" in the cache but we issued a query with DO bit set 1733 // to get the RRSIGs e.g., if you have two questions one of which does not require 1734 // DNSSEC validation. When the RRSIG is added to the cache, we need to deliver 1735 // the response to the question. The RRSIG type won't match the q->qtype and hence 1736 // we need to bypass the check in that case. 1737 if (rr->rrtype == kDNSType_RRSIG && q->ValidatingResponse) 1738 { 1739 const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; 1740 rdataRRSig *rrsig = (rdataRRSig *)rdb->data; 1741 mDNSu16 typeCovered = swap16(rrsig->typeCovered); 1742 debugf("DNSSECRecordAnswersQuestion: Matching RRSIG typeCovered %s", DNSTypeName(typeCovered)); 1743 if (typeCovered != kDNSType_CNAME && typeCovered != q->qtype) 1744 { 1745 debugf("DNSSECRecordAnswersQuestion: RRSIG did not match question %##s (%s)", q->qname.c, 1746 DNSTypeName(q->qtype)); 1747 return mDNSfalse; 1748 } 1749 LogInfo("DNSSECRecordAnswersQuestion: RRSIG matched question %##s (%s)", q->qname.c, 1750 DNSTypeName(q->qtype)); 1751 *checkType = mDNSfalse; 1752 return mDNStrue; 1753 } 1754 // If the NSEC record asserts the non-existence of a name looked up by the question, we would 1755 // typically answer that e.g., the bitmap asserts that q->qtype does not exist. If we have 1756 // to prove the non-existence as required by ValidatingResponse and ValidationRequired question, 1757 // then we should not answer that as it may not be the right one always. We may need more than 1758 // one NSEC to prove the non-existence. 1759 if (rr->rrtype == kDNSType_NSEC && DNSSECQuestion(q)) 1760 { 1761 debugf("DNSSECRecordAnswersQuestion: Question %##s (%s) matched record %##s (NSEC)", q->qname.c, 1762 DNSTypeName(q->qtype), rr->name->c); 1763 return mDNSfalse; 1764 } 1765 return mDNStrue; 1766 } 1767 1768 // ResourceRecordAnswersQuestion returns mDNStrue if the given resource record is a valid answer to the given question. 1769 // SameNameRecordAnswersQuestion is the same, except it skips the expensive SameDomainName() call. 1770 // SameDomainName() is generally cheap when the names don't match, but expensive when they do match, 1771 // because it has to check all the way to the end of the names to be sure. 1772 // In cases where we know in advance that the names match it's especially advantageous to skip the 1773 // SameDomainName() call because that's precisely the time when it's most expensive and least useful. 1774 1775 mDNSexport mDNSBool SameNameRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q) 1776 { 1777 mDNSBool checkType = mDNStrue; 1778 1779 // LocalOnly/P2P questions can be answered with AuthRecordAny in this function. LocalOnly/P2P records 1780 // are handled in LocalOnlyRecordAnswersQuestion 1781 if ((rr->InterfaceID == mDNSInterface_LocalOnly) || (rr->InterfaceID == mDNSInterface_P2P)) 1782 { 1783 LogMsg("SameNameRecordAnswersQuestion: ERROR!! called with LocalOnly ResourceRecord %p, Question %p", rr->InterfaceID, q->InterfaceID); 1784 return mDNSfalse; 1785 } 1786 if (QuerySuppressed(q)) 1787 return mDNSfalse; 1788 1789 if (rr->InterfaceID && 1790 q->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly && 1791 rr->InterfaceID != q->InterfaceID) return(mDNSfalse); 1792 1793 // Resource record received via unicast, the resolver group ID should match ? 1794 if (!rr->InterfaceID) 1795 { 1796 mDNSu16 idr = (rr->rDNSServer ? rr->rDNSServer->resGroupID : 0); 1797 mDNSu16 idq = (q->qDNSServer ? q->qDNSServer->resGroupID : 0); 1798 if (idr != idq) return(mDNSfalse); 1799 if (!DNSSECRecordAnswersQuestion(rr, q, &checkType)) return mDNSfalse; 1800 } 1801 1802 // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question 1803 if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); 1804 1805 // CNAME answers question of any type and a negative cache record should not prevent us from querying other 1806 // valid types at the same name. 1807 if (rr->rrtype == kDNSType_CNAME && rr->RecordType == kDNSRecordTypePacketNegative && rr->rrtype != q->qtype) 1808 return mDNSfalse; 1809 1810 // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class. 1811 if (checkType && !RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse); 1812 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); 1813 1814 #if APPLE_OSX_mDNSResponder 1815 if (!mDNSPlatformValidRecordForQuestion(rr, q)) 1816 return mDNSfalse; 1817 #endif // APPLE_OSX_mDNSResponder 1818 1819 if (!AnonInfoAnswersQuestion(rr, q)) 1820 return mDNSfalse; 1821 1822 return(mDNStrue); 1823 } 1824 1825 mDNSexport mDNSBool ResourceRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q) 1826 { 1827 if (!SameNameRecordAnswersQuestion(rr, q)) 1828 return mDNSfalse; 1829 1830 return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); 1831 } 1832 1833 // We have a separate function to handle LocalOnly AuthRecords because they can be created with 1834 // a valid InterfaceID (e.g., scoped /etc/hosts) and can be used to answer unicast questions unlike 1835 // multicast resource records (which has a valid InterfaceID) which can't be used to answer 1836 // unicast questions. ResourceRecordAnswersQuestion/SameNameRecordAnswersQuestion can't tell whether 1837 // a resource record is multicast or LocalOnly by just looking at the ResourceRecord because 1838 // LocalOnly records are truly identified by ARType in the AuthRecord. As P2P and LocalOnly record 1839 // are kept in the same hash table, we use the same function to make it easy for the callers when 1840 // they walk the hash table to answer LocalOnly/P2P questions 1841 // 1842 mDNSexport mDNSBool LocalOnlyRecordAnswersQuestion(AuthRecord *const ar, const DNSQuestion *const q) 1843 { 1844 ResourceRecord *rr = &ar->resrec; 1845 1846 // mDNSInterface_Any questions can be answered with LocalOnly/P2P records in this function. AuthRecord_Any 1847 // records are handled in ResourceRecordAnswersQuestion/SameNameRecordAnswersQuestion 1848 if (RRAny(ar)) 1849 { 1850 LogMsg("LocalOnlyRecordAnswersQuestion: ERROR!! called with regular AuthRecordAny %##s", rr->name->c); 1851 return mDNSfalse; 1852 } 1853 1854 // Questions with mDNSInterface_LocalOnly InterfaceID should be answered with all resource records that are 1855 // *local* to the machine. These include resource records that have InterfaceID set to mDNSInterface_LocalOnly, 1856 // mDNSInterface_Any and any other real InterfaceID. Hence, LocalOnly questions should not be checked against 1857 // the InterfaceID in the resource record. 1858 // 1859 // mDNSInterface_Unicast does not indicate any scope and hence treat them like mDNSInterface_Any. 1860 1861 if (rr->InterfaceID && 1862 q->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly && q->InterfaceID != mDNSInterface_Unicast && 1863 rr->InterfaceID != q->InterfaceID) return(mDNSfalse); 1864 1865 // Entries in /etc/hosts are added as LocalOnly resource records. The LocalOnly resource records 1866 // may have a scope e.g., fe80::1%en0. The question may be scoped or not: the InterfaceID may be set 1867 // to mDNSInterface_Any, mDNSInterface_LocalOnly or a real InterfaceID (scoped). 1868 // 1869 // 1) Question: Any, LocalOnly Record: no scope. This question should be answered with this record. 1870 // 1871 // 2) Question: Any, LocalOnly Record: scoped. This question should be answered with the record because 1872 // traditionally applications never specify scope e.g., getaddrinfo, but need to be able 1873 // to get to /etc/hosts entries. 1874 // 1875 // 3) Question: Scoped (LocalOnly or InterfaceID), LocalOnly Record: no scope. This is the inverse of (2). 1876 // If we register a LocalOnly record, we need to answer a LocalOnly question. If the /etc/hosts has a 1877 // non scoped entry, it may not make sense to answer a scoped question. But we can't tell these two 1878 // cases apart. As we currently answer LocalOnly question with LocalOnly record, we continue to do so. 1879 // 1880 // 4) Question: Scoped (LocalOnly or InterfaceID), LocalOnly Record: scoped. LocalOnly questions should be 1881 // answered with any resource record where as if it has a valid InterfaceID, the scope should match. 1882 // 1883 // (1) and (2) is bypassed because we check for a non-NULL InterfaceID above. For (3), the InterfaceID is NULL 1884 // and hence bypassed above. For (4) we bypassed LocalOnly questions and checked the scope of the record 1885 // against the question. 1886 // 1887 // For P2P, InterfaceIDs of the question and the record should match. 1888 1889 // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question. 1890 // LocalOnly authoritative answers are exempt. LocalOnly authoritative answers are used for /etc/host entries. 1891 // We don't want a local process to be able to create a fake LocalOnly address record for "www.bigbank.com" which would then 1892 // cause other applications (e.g. Safari) to connect to the wrong address. The rpc to register records filters out records 1893 // with names that don't end in local and have mDNSInterface_LocalOnly set. 1894 // 1895 // Note: The check is bypassed for LocalOnly and for P2P it is not needed as only .local records are registered and for 1896 // a question to match its names, it also has to end in .local and that question can't be a unicast question (See 1897 // Question_uDNS macro and its usage). As P2P does not enforce .local only registrations we still make this check 1898 // and also makes it future proof. 1899 1900 if (ar->ARType != AuthRecordLocalOnly && rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); 1901 1902 // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class. 1903 if (!RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse); 1904 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); 1905 1906 if (!AnonInfoAnswersQuestion(rr, q)) 1907 return mDNSfalse; 1908 1909 return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); 1910 } 1911 1912 mDNSexport mDNSBool AnyTypeRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q) 1913 { 1914 // LocalOnly/P2P questions can be answered with AuthRecordAny in this function. LocalOnly/P2P records 1915 // are handled in LocalOnlyRecordAnswersQuestion 1916 if ((rr->InterfaceID == mDNSInterface_LocalOnly) || (rr->InterfaceID == mDNSInterface_P2P)) 1917 { 1918 LogMsg("AnyTypeRecordAnswersQuestion: ERROR!! called with LocalOnly ResourceRecord %p, Question %p", rr->InterfaceID, q->InterfaceID); 1919 return mDNSfalse; 1920 } 1921 if (rr->InterfaceID && 1922 q->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly && 1923 rr->InterfaceID != q->InterfaceID) return(mDNSfalse); 1924 1925 // Resource record received via unicast, the resolver group ID should match ? 1926 // Note that Auth Records are normally setup with NULL InterfaceID and 1927 // both the DNSServers are assumed to be NULL in that case 1928 if (!rr->InterfaceID) 1929 { 1930 mDNSu16 idr = (rr->rDNSServer ? rr->rDNSServer->resGroupID : 0); 1931 mDNSu16 idq = (q->qDNSServer ? q->qDNSServer->resGroupID : 0); 1932 if (idr != idq) return(mDNSfalse); 1933 } 1934 1935 // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question 1936 if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); 1937 1938 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); 1939 1940 if (!AnonInfoAnswersQuestion(rr, q)) 1941 return mDNSfalse; 1942 1943 return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); 1944 } 1945 1946 // This is called with both unicast resource record and multicast resource record. The question that 1947 // received the unicast response could be the regular unicast response from a DNS server or a response 1948 // to a mDNS QU query. The main reason we need this function is that we can't compare DNSServers between the 1949 // question and the resource record because the resource record is not completely initialized in 1950 // mDNSCoreReceiveResponse when this function is called. 1951 mDNSexport mDNSBool ResourceRecordAnswersUnicastResponse(const ResourceRecord *const rr, const DNSQuestion *const q) 1952 { 1953 mDNSBool checkType = mDNStrue; 1954 1955 if (QuerySuppressed(q)) 1956 return mDNSfalse; 1957 1958 // For resource records created using multicast, the InterfaceIDs have to match 1959 if (rr->InterfaceID && 1960 q->InterfaceID && rr->InterfaceID != q->InterfaceID) return(mDNSfalse); 1961 1962 // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question. 1963 if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); 1964 1965 if (!DNSSECRecordAnswersQuestion(rr, q, &checkType)) return mDNSfalse; 1966 1967 // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class. 1968 if (checkType && !RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse); 1969 1970 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); 1971 1972 return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); 1973 } 1974 1975 mDNSexport mDNSu16 GetRDLength(const ResourceRecord *const rr, mDNSBool estimate) 1976 { 1977 const RDataBody2 *const rd = (RDataBody2 *)rr->rdata->u.data; 1978 const domainname *const name = estimate ? rr->name : mDNSNULL; 1979 if (rr->rrclass == kDNSQClass_ANY) return(rr->rdlength); // Used in update packets to mean "Delete An RRset" (RFC 2136) 1980 else switch (rr->rrtype) 1981 { 1982 case kDNSType_A: return(sizeof(rd->ipv4)); 1983 1984 case kDNSType_NS: 1985 case kDNSType_CNAME: 1986 case kDNSType_PTR: 1987 case kDNSType_DNAME: return(CompressedDomainNameLength(&rd->name, name)); 1988 1989 case kDNSType_SOA: return (mDNSu16)(CompressedDomainNameLength(&rd->soa.mname, name) + 1990 CompressedDomainNameLength(&rd->soa.rname, name) + 1991 5 * sizeof(mDNSOpaque32)); 1992 1993 case kDNSType_NULL: 1994 case kDNSType_TSIG: 1995 case kDNSType_TXT: 1996 case kDNSType_X25: 1997 case kDNSType_ISDN: 1998 case kDNSType_LOC: 1999 case kDNSType_DHCID: return(rr->rdlength); // Not self-describing, so have to just trust rdlength 2000 2001 case kDNSType_HINFO: return (mDNSu16)(2 + (int)rd->data[0] + (int)rd->data[1 + (int)rd->data[0]]); 2002 2003 case kDNSType_MX: 2004 case kDNSType_AFSDB: 2005 case kDNSType_RT: 2006 case kDNSType_KX: return (mDNSu16)(2 + CompressedDomainNameLength(&rd->mx.exchange, name)); 2007 2008 case kDNSType_RP: return (mDNSu16)(CompressedDomainNameLength(&rd->rp.mbox, name) + 2009 CompressedDomainNameLength(&rd->rp.txt, name)); 2010 2011 case kDNSType_PX: return (mDNSu16)(2 + CompressedDomainNameLength(&rd->px.map822, name) + 2012 CompressedDomainNameLength(&rd->px.mapx400, name)); 2013 2014 case kDNSType_AAAA: return(sizeof(rd->ipv6)); 2015 2016 case kDNSType_SRV: return (mDNSu16)(6 + CompressedDomainNameLength(&rd->srv.target, name)); 2017 2018 case kDNSType_OPT: return(rr->rdlength); 2019 2020 case kDNSType_NSEC: { 2021 domainname *next = (domainname *)rd->data; 2022 int dlen = DomainNameLength(next); 2023 // 2024 if (UNICAST_NSEC(rr)) 2025 return (mDNSu16)(CompressedDomainNameLength(next, name) + rr->rdlength - dlen); 2026 else 2027 return (mDNSu16)((estimate ? 2 : dlen) + rr->rdlength - dlen); 2028 } 2029 2030 default: debugf("Warning! Don't know how to get length of resource type %d", rr->rrtype); 2031 return(rr->rdlength); 2032 } 2033 } 2034 2035 // When a local client registers (or updates) a record, we use this routine to do some simple validation checks 2036 // to help reduce the risk of bogus malformed data on the network 2037 mDNSexport mDNSBool ValidateRData(const mDNSu16 rrtype, const mDNSu16 rdlength, const RData *const rd) 2038 { 2039 mDNSu16 len; 2040 2041 switch(rrtype) 2042 { 2043 case kDNSType_A: return(rdlength == sizeof(mDNSv4Addr)); 2044 2045 case kDNSType_NS: // Same as PTR 2046 case kDNSType_MD: // Same as PTR 2047 case kDNSType_MF: // Same as PTR 2048 case kDNSType_CNAME: // Same as PTR 2049 //case kDNSType_SOA not checked 2050 case kDNSType_MB: // Same as PTR 2051 case kDNSType_MG: // Same as PTR 2052 case kDNSType_MR: // Same as PTR 2053 //case kDNSType_NULL not checked (no specified format, so always valid) 2054 //case kDNSType_WKS not checked 2055 case kDNSType_PTR: len = DomainNameLengthLimit(&rd->u.name, rd->u.data + rdlength); 2056 return(len <= MAX_DOMAIN_NAME && rdlength == len); 2057 2058 case kDNSType_HINFO: // Same as TXT (roughly) 2059 case kDNSType_MINFO: // Same as TXT (roughly) 2060 case kDNSType_TXT: if (!rdlength) return(mDNSfalse); // TXT record has to be at least one byte (RFC 1035) 2061 { 2062 const mDNSu8 *ptr = rd->u.txt.c; 2063 const mDNSu8 *end = rd->u.txt.c + rdlength; 2064 while (ptr < end) ptr += 1 + ptr[0]; 2065 return (ptr == end); 2066 } 2067 2068 case kDNSType_AAAA: return(rdlength == sizeof(mDNSv6Addr)); 2069 2070 case kDNSType_MX: // Must be at least two-byte preference, plus domainname 2071 // Call to DomainNameLengthLimit() implicitly enforces both requirements for us 2072 len = DomainNameLengthLimit(&rd->u.mx.exchange, rd->u.data + rdlength); 2073 return(len <= MAX_DOMAIN_NAME && rdlength == 2+len); 2074 2075 case kDNSType_SRV: // Must be at least priority+weight+port, plus domainname 2076 // Call to DomainNameLengthLimit() implicitly enforces both requirements for us 2077 len = DomainNameLengthLimit(&rd->u.srv.target, rd->u.data + rdlength); 2078 return(len <= MAX_DOMAIN_NAME && rdlength == 6+len); 2079 2080 //case kDNSType_NSEC not checked 2081 2082 default: return(mDNStrue); // Allow all other types without checking 2083 } 2084 } 2085 2086 // *************************************************************************** 2087 #if COMPILER_LIKES_PRAGMA_MARK 2088 #pragma mark - 2089 #pragma mark - DNS Message Creation Functions 2090 #endif 2091 2092 mDNSexport void InitializeDNSMessage(DNSMessageHeader *h, mDNSOpaque16 id, mDNSOpaque16 flags) 2093 { 2094 h->id = id; 2095 h->flags = flags; 2096 h->numQuestions = 0; 2097 h->numAnswers = 0; 2098 h->numAuthorities = 0; 2099 h->numAdditionals = 0; 2100 } 2101 2102 mDNSexport const mDNSu8 *FindCompressionPointer(const mDNSu8 *const base, const mDNSu8 *const end, const mDNSu8 *const domname) 2103 { 2104 const mDNSu8 *result = end - *domname - 1; 2105 2106 if (*domname == 0) return(mDNSNULL); // There's no point trying to match just the root label 2107 2108 // This loop examines each possible starting position in packet, starting end of the packet and working backwards 2109 while (result >= base) 2110 { 2111 // If the length byte and first character of the label match, then check further to see 2112 // if this location in the packet will yield a useful name compression pointer. 2113 if (result[0] == domname[0] && result[1] == domname[1]) 2114 { 2115 const mDNSu8 *name = domname; 2116 const mDNSu8 *targ = result; 2117 while (targ + *name < end) 2118 { 2119 // First see if this label matches 2120 int i; 2121 const mDNSu8 *pointertarget; 2122 for (i=0; i <= *name; i++) if (targ[i] != name[i]) break; 2123 if (i <= *name) break; // If label did not match, bail out 2124 targ += 1 + *name; // Else, did match, so advance target pointer 2125 name += 1 + *name; // and proceed to check next label 2126 if (*name == 0 && *targ == 0) return(result); // If no more labels, we found a match! 2127 if (*name == 0) break; // If no more labels to match, we failed, so bail out 2128 2129 // The label matched, so now follow the pointer (if appropriate) and then see if the next label matches 2130 if (targ[0] < 0x40) continue; // If length value, continue to check next label 2131 if (targ[0] < 0xC0) break; // If 40-BF, not valid 2132 if (targ+1 >= end) break; // Second byte not present! 2133 pointertarget = base + (((mDNSu16)(targ[0] & 0x3F)) << 8) + targ[1]; 2134 if (targ < pointertarget) break; // Pointertarget must point *backwards* in the packet 2135 if (pointertarget[0] >= 0x40) break; // Pointertarget must point to a valid length byte 2136 targ = pointertarget; 2137 } 2138 } 2139 result--; // We failed to match at this search position, so back up the tentative result pointer and try again 2140 } 2141 return(mDNSNULL); 2142 } 2143 2144 // Put a string of dot-separated labels as length-prefixed labels 2145 // domainname is a fully-qualified name (i.e. assumed to be ending in a dot, even if it doesn't) 2146 // msg points to the message we're building (pass mDNSNULL if we don't want to use compression pointers) 2147 // end points to the end of the message so far 2148 // ptr points to where we want to put the name 2149 // limit points to one byte past the end of the buffer that we must not overrun 2150 // domainname is the name to put 2151 mDNSexport mDNSu8 *putDomainNameAsLabels(const DNSMessage *const msg, 2152 mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name) 2153 { 2154 const mDNSu8 *const base = (const mDNSu8 *)msg; 2155 const mDNSu8 * np = name->c; 2156 const mDNSu8 *const max = name->c + MAX_DOMAIN_NAME; // Maximum that's valid 2157 const mDNSu8 * pointer = mDNSNULL; 2158 const mDNSu8 *const searchlimit = ptr; 2159 2160 if (!ptr) { LogMsg("putDomainNameAsLabels %##s ptr is null", name->c); return(mDNSNULL); } 2161 2162 if (!*np) // If just writing one-byte root label, make sure we have space for that 2163 { 2164 if (ptr >= limit) return(mDNSNULL); 2165 } 2166 else // else, loop through writing labels and/or a compression offset 2167 { 2168 do { 2169 if (*np > MAX_DOMAIN_LABEL) 2170 { LogMsg("Malformed domain name %##s (label more than 63 bytes)", name->c); return(mDNSNULL); } 2171 2172 // This check correctly allows for the final trailing root label: 2173 // e.g. 2174 // Suppose our domain name is exactly 256 bytes long, including the final trailing root label. 2175 // Suppose np is now at name->c[249], and we're about to write our last non-null label ("local"). 2176 // We know that max will be at name->c[256] 2177 // That means that np + 1 + 5 == max - 1, so we (just) pass the "if" test below, write our 2178 // six bytes, then exit the loop, write the final terminating root label, and the domain 2179 // name we've written is exactly 256 bytes long, exactly at the correct legal limit. 2180 // If the name is one byte longer, then we fail the "if" test below, and correctly bail out. 2181 if (np + 1 + *np >= max) 2182 { LogMsg("Malformed domain name %##s (more than 256 bytes)", name->c); return(mDNSNULL); } 2183 2184 if (base) pointer = FindCompressionPointer(base, searchlimit, np); 2185 if (pointer) // Use a compression pointer if we can 2186 { 2187 const mDNSu16 offset = (mDNSu16)(pointer - base); 2188 if (ptr+2 > limit) return(mDNSNULL); // If we don't have two bytes of space left, give up 2189 *ptr++ = (mDNSu8)(0xC0 | (offset >> 8)); 2190 *ptr++ = (mDNSu8)( offset & 0xFF); 2191 return(ptr); 2192 } 2193 else // Else copy one label and try again 2194 { 2195 int i; 2196 mDNSu8 len = *np++; 2197 // If we don't at least have enough space for this label *plus* a terminating zero on the end, give up 2198 if (ptr + 1 + len >= limit) return(mDNSNULL); 2199 *ptr++ = len; 2200 for (i=0; i<len; i++) *ptr++ = *np++; 2201 } 2202 } while (*np); // While we've got characters remaining in the name, continue 2203 } 2204 2205 *ptr++ = 0; // Put the final root label 2206 return(ptr); 2207 } 2208 2209 mDNSlocal mDNSu8 *putVal16(mDNSu8 *ptr, mDNSu16 val) 2210 { 2211 ptr[0] = (mDNSu8)((val >> 8 ) & 0xFF); 2212 ptr[1] = (mDNSu8)((val ) & 0xFF); 2213 return ptr + sizeof(mDNSOpaque16); 2214 } 2215 2216 mDNSlocal mDNSu8 *putVal32(mDNSu8 *ptr, mDNSu32 val) 2217 { 2218 ptr[0] = (mDNSu8)((val >> 24) & 0xFF); 2219 ptr[1] = (mDNSu8)((val >> 16) & 0xFF); 2220 ptr[2] = (mDNSu8)((val >> 8) & 0xFF); 2221 ptr[3] = (mDNSu8)((val ) & 0xFF); 2222 return ptr + sizeof(mDNSu32); 2223 } 2224 2225 // Copy the RDATA information. The actual in memory storage for the data might be bigger than what the rdlength 2226 // says. Hence, the only way to copy out the data from a resource record is to use putRData. 2227 // msg points to the message we're building (pass mDNSNULL for "msg" if we don't want to use compression pointers) 2228 mDNSexport mDNSu8 *putRData(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const ResourceRecord *const rr) 2229 { 2230 const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; 2231 switch (rr->rrtype) 2232 { 2233 case kDNSType_A: if (rr->rdlength != 4) 2234 { debugf("putRData: Illegal length %d for kDNSType_A", rr->rdlength); return(mDNSNULL); } 2235 if (ptr + 4 > limit) return(mDNSNULL); 2236 *ptr++ = rdb->ipv4.b[0]; 2237 *ptr++ = rdb->ipv4.b[1]; 2238 *ptr++ = rdb->ipv4.b[2]; 2239 *ptr++ = rdb->ipv4.b[3]; 2240 return(ptr); 2241 2242 case kDNSType_NS: 2243 case kDNSType_CNAME: 2244 case kDNSType_PTR: 2245 case kDNSType_DNAME: return(putDomainNameAsLabels(msg, ptr, limit, &rdb->name)); 2246 2247 case kDNSType_SOA: ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->soa.mname); 2248 if (!ptr) return(mDNSNULL); 2249 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->soa.rname); 2250 if (!ptr || ptr + 20 > limit) return(mDNSNULL); 2251 ptr = putVal32(ptr, rdb->soa.serial); 2252 ptr = putVal32(ptr, rdb->soa.refresh); 2253 ptr = putVal32(ptr, rdb->soa.retry); 2254 ptr = putVal32(ptr, rdb->soa.expire); 2255 ptr = putVal32(ptr, rdb->soa.min); 2256 return(ptr); 2257 2258 case kDNSType_NULL: 2259 case kDNSType_HINFO: 2260 case kDNSType_TSIG: 2261 case kDNSType_TXT: 2262 case kDNSType_X25: 2263 case kDNSType_ISDN: 2264 case kDNSType_LOC: 2265 case kDNSType_DHCID: if (ptr + rr->rdlength > limit) return(mDNSNULL); 2266 mDNSPlatformMemCopy(ptr, rdb->data, rr->rdlength); 2267 return(ptr + rr->rdlength); 2268 2269 case kDNSType_MX: 2270 case kDNSType_AFSDB: 2271 case kDNSType_RT: 2272 case kDNSType_KX: if (ptr + 3 > limit) return(mDNSNULL); 2273 ptr = putVal16(ptr, rdb->mx.preference); 2274 return(putDomainNameAsLabels(msg, ptr, limit, &rdb->mx.exchange)); 2275 2276 case kDNSType_RP: ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->rp.mbox); 2277 if (!ptr) return(mDNSNULL); 2278 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->rp.txt); 2279 return(ptr); 2280 2281 case kDNSType_PX: if (ptr + 5 > limit) return(mDNSNULL); 2282 ptr = putVal16(ptr, rdb->px.preference); 2283 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->px.map822); 2284 if (!ptr) return(mDNSNULL); 2285 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->px.mapx400); 2286 return(ptr); 2287 2288 case kDNSType_AAAA: if (rr->rdlength != sizeof(rdb->ipv6)) 2289 { debugf("putRData: Illegal length %d for kDNSType_AAAA", rr->rdlength); return(mDNSNULL); } 2290 if (ptr + sizeof(rdb->ipv6) > limit) return(mDNSNULL); 2291 mDNSPlatformMemCopy(ptr, &rdb->ipv6, sizeof(rdb->ipv6)); 2292 return(ptr + sizeof(rdb->ipv6)); 2293 2294 case kDNSType_SRV: if (ptr + 7 > limit) return(mDNSNULL); 2295 *ptr++ = (mDNSu8)(rdb->srv.priority >> 8); 2296 *ptr++ = (mDNSu8)(rdb->srv.priority & 0xFF); 2297 *ptr++ = (mDNSu8)(rdb->srv.weight >> 8); 2298 *ptr++ = (mDNSu8)(rdb->srv.weight & 0xFF); 2299 *ptr++ = rdb->srv.port.b[0]; 2300 *ptr++ = rdb->srv.port.b[1]; 2301 return(putDomainNameAsLabels(msg, ptr, limit, &rdb->srv.target)); 2302 2303 case kDNSType_OPT: { 2304 int len = 0; 2305 const rdataOPT *opt; 2306 const rdataOPT *const end = (const rdataOPT *)&rr->rdata->u.data[rr->rdlength]; 2307 for (opt = &rr->rdata->u.opt[0]; opt < end; opt++) 2308 len += DNSOpt_Data_Space(opt); 2309 if (ptr + len > limit) 2310 { 2311 LogMsg("ERROR: putOptRData - out of space"); 2312 return mDNSNULL; 2313 } 2314 for (opt = &rr->rdata->u.opt[0]; opt < end; opt++) 2315 { 2316 const int space = DNSOpt_Data_Space(opt); 2317 ptr = putVal16(ptr, opt->opt); 2318 ptr = putVal16(ptr, (mDNSu16)space - 4); 2319 switch (opt->opt) 2320 { 2321 case kDNSOpt_LLQ: 2322 ptr = putVal16(ptr, opt->u.llq.vers); 2323 ptr = putVal16(ptr, opt->u.llq.llqOp); 2324 ptr = putVal16(ptr, opt->u.llq.err); 2325 mDNSPlatformMemCopy(ptr, opt->u.llq.id.b, 8); // 8-byte id 2326 ptr += 8; 2327 ptr = putVal32(ptr, opt->u.llq.llqlease); 2328 break; 2329 case kDNSOpt_Lease: 2330 ptr = putVal32(ptr, opt->u.updatelease); 2331 break; 2332 case kDNSOpt_Owner: 2333 *ptr++ = opt->u.owner.vers; 2334 *ptr++ = opt->u.owner.seq; 2335 mDNSPlatformMemCopy(ptr, opt->u.owner.HMAC.b, 6); // 6-byte Host identifier 2336 ptr += 6; 2337 if (space >= DNSOpt_OwnerData_ID_Wake_Space) 2338 { 2339 mDNSPlatformMemCopy(ptr, opt->u.owner.IMAC.b, 6); // 6-byte interface MAC 2340 ptr += 6; 2341 if (space > DNSOpt_OwnerData_ID_Wake_Space) 2342 { 2343 mDNSPlatformMemCopy(ptr, opt->u.owner.password.b, space - DNSOpt_OwnerData_ID_Wake_Space); 2344 ptr += space - DNSOpt_OwnerData_ID_Wake_Space; 2345 } 2346 } 2347 break; 2348 case kDNSOpt_Trace: 2349 *ptr++ = opt->u.tracer.platf; 2350 ptr = putVal32(ptr, opt->u.tracer.mDNSv); 2351 break; 2352 } 2353 } 2354 return ptr; 2355 } 2356 2357 case kDNSType_NSEC: { 2358 // For NSEC records, rdlength represents the exact number of bytes 2359 // of in memory storage. 2360 int len = rr->rdlength; 2361 mDNSu8 *nsec = (mDNSu8 *)rdb->data; 2362 domainname *name = (domainname *)nsec; 2363 int dlen; 2364 2365 dlen = DomainNameLength(name); 2366 len -= dlen; 2367 nsec += dlen; 2368 // This function is called when we are sending a NSEC record as part of mDNS, 2369 // or to copy the data to any other buffer needed which could be a mDNS or uDNS 2370 // NSEC record. The only time compression is used that when we are sending it 2371 // in mDNS (indicated by non-NULL "msg") and hence we handle mDNS case 2372 // separately. 2373 if (!UNICAST_NSEC(rr)) 2374 { 2375 mDNSu8 *save = ptr; 2376 int i, j, wlen; 2377 wlen = *(nsec + 1); 2378 nsec += 2; // Skip the window number and len 2379 len -= 2; 2380 2381 // For our simplified use of NSEC synthetic records: 2382 // 2383 // nextname is always the record's own name, 2384 // the block number is always 0, 2385 // the count byte is a value in the range 1-32, 2386 // followed by the 1-32 data bytes 2387 // 2388 // Note: When we send the NSEC record in mDNS, the window size is set to 32. 2389 // We need to find out what the last non-NULL byte is. If we are copying out 2390 // from an RDATA, we have the right length. As we need to handle both the case, 2391 // we loop to find the right value instead of blindly using len to copy. 2392 2393 for (i=wlen; i>0; i--) if (nsec[i-1]) break; 2394 2395 ptr = putDomainNameAsLabels(msg, ptr, limit, rr->name); 2396 if (!ptr) { LogInfo("putRData: Can't put name, Length %d, record %##s", limit - save, rr->name->c); return(mDNSNULL); } 2397 if (i) // Only put a block if at least one type exists for this name 2398 { 2399 if (ptr + 2 + i > limit) { LogInfo("putRData: Can't put window, Length %d, i %d, record %##s", limit - ptr, i, rr->name->c); return(mDNSNULL); } 2400 *ptr++ = 0; 2401 *ptr++ = (mDNSu8)i; 2402 for (j=0; j<i; j++) *ptr++ = nsec[j]; 2403 } 2404 return ptr; 2405 } 2406 else 2407 { 2408 int win, wlen; 2409 2410 // Sanity check whether the bitmap is good 2411 while (len) 2412 { 2413 if (len < 3) 2414 { LogMsg("putRData: invalid length %d", len); return mDNSNULL; } 2415 2416 win = *nsec++; 2417 wlen = *nsec++; 2418 len -= 2; 2419 if (len < wlen || wlen < 1 || wlen > 32) 2420 { LogMsg("putRData: invalid window length %d", wlen); return mDNSNULL; } 2421 if (win < 0 || win >= 256) 2422 { LogMsg("putRData: invalid window %d", win); return mDNSNULL; } 2423 2424 nsec += wlen; 2425 len -= wlen; 2426 } 2427 if (ptr + rr->rdlength > limit) { LogMsg("putRData: NSEC rdlength beyond limit %##s (%s), ptr %p, rdlength %d, limit %p", rr->name->c, DNSTypeName(rr->rrtype), ptr, rr->rdlength, limit); return(mDNSNULL);} 2428 2429 // No compression allowed for "nxt", just copy the data. 2430 mDNSPlatformMemCopy(ptr, rdb->data, rr->rdlength); 2431 return(ptr + rr->rdlength); 2432 } 2433 } 2434 2435 default: debugf("putRData: Warning! Writing unknown resource type %d as raw data", rr->rrtype); 2436 if (ptr + rr->rdlength > limit) return(mDNSNULL); 2437 mDNSPlatformMemCopy(ptr, rdb->data, rr->rdlength); 2438 return(ptr + rr->rdlength); 2439 } 2440 } 2441 2442 #define IsUnicastUpdate(X) (!mDNSOpaque16IsZero((X)->h.id) && ((X)->h.flags.b[0] & kDNSFlag0_OP_Mask) == kDNSFlag0_OP_Update) 2443 2444 mDNSexport mDNSu8 *PutResourceRecordTTLWithLimit(DNSMessage *const msg, mDNSu8 *ptr, mDNSu16 *count, ResourceRecord *rr, mDNSu32 ttl, const mDNSu8 *limit) 2445 { 2446 mDNSu8 *endofrdata; 2447 mDNSu16 actualLength; 2448 // When sending SRV to conventional DNS server (i.e. in DNS update requests) we should not do name compression on the rdata (RFC 2782) 2449 const DNSMessage *const rdatacompressionbase = (IsUnicastUpdate(msg) && rr->rrtype == kDNSType_SRV) ? mDNSNULL : msg; 2450 2451 if (rr->RecordType == kDNSRecordTypeUnregistered) 2452 { 2453 LogMsg("PutResourceRecordTTLWithLimit ERROR! Attempt to put kDNSRecordTypeUnregistered %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype)); 2454 return(ptr); 2455 } 2456 2457 if (!ptr) 2458 { 2459 LogMsg("PutResourceRecordTTLWithLimit ptr is null %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype)); 2460 return(mDNSNULL); 2461 } 2462 2463 ptr = putDomainNameAsLabels(msg, ptr, limit, rr->name); 2464 // If we're out-of-space, return mDNSNULL 2465 if (!ptr || ptr + 10 >= limit) 2466 { 2467 LogInfo("PutResourceRecordTTLWithLimit: can't put name, out of space %##s (%s), ptr %p, limit %p", rr->name->c, 2468 DNSTypeName(rr->rrtype), ptr, limit); 2469 return(mDNSNULL); 2470 } 2471 ptr[0] = (mDNSu8)(rr->rrtype >> 8); 2472 ptr[1] = (mDNSu8)(rr->rrtype & 0xFF); 2473 ptr[2] = (mDNSu8)(rr->rrclass >> 8); 2474 ptr[3] = (mDNSu8)(rr->rrclass & 0xFF); 2475 ptr[4] = (mDNSu8)((ttl >> 24) & 0xFF); 2476 ptr[5] = (mDNSu8)((ttl >> 16) & 0xFF); 2477 ptr[6] = (mDNSu8)((ttl >> 8) & 0xFF); 2478 ptr[7] = (mDNSu8)( ttl & 0xFF); 2479 // ptr[8] and ptr[9] filled in *after* we find out how much space the rdata takes 2480 2481 endofrdata = putRData(rdatacompressionbase, ptr+10, limit, rr); 2482 if (!endofrdata) 2483 { 2484 LogInfo("PutResourceRecordTTLWithLimit: Ran out of space in PutResourceRecord for %##s (%s), ptr %p, limit %p", rr->name->c, 2485 DNSTypeName(rr->rrtype), ptr+10, limit); 2486 return(mDNSNULL); 2487 } 2488 2489 // Go back and fill in the actual number of data bytes we wrote 2490 // (actualLength can be less than rdlength when domain name compression is used) 2491 actualLength = (mDNSu16)(endofrdata - ptr - 10); 2492 ptr[8] = (mDNSu8)(actualLength >> 8); 2493 ptr[9] = (mDNSu8)(actualLength & 0xFF); 2494 2495 if (count) (*count)++; 2496 else LogMsg("PutResourceRecordTTL: ERROR: No target count to update for %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype)); 2497 return(endofrdata); 2498 } 2499 2500 mDNSlocal mDNSu8 *putEmptyResourceRecord(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, mDNSu16 *count, const AuthRecord *rr) 2501 { 2502 ptr = putDomainNameAsLabels(msg, ptr, limit, rr->resrec.name); 2503 if (!ptr || ptr + 10 > limit) return(mDNSNULL); // If we're out-of-space, return mDNSNULL 2504 ptr[0] = (mDNSu8)(rr->resrec.rrtype >> 8); // Put type 2505 ptr[1] = (mDNSu8)(rr->resrec.rrtype & 0xFF); 2506 ptr[2] = (mDNSu8)(rr->resrec.rrclass >> 8); // Put class 2507 ptr[3] = (mDNSu8)(rr->resrec.rrclass & 0xFF); 2508 ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // TTL is zero 2509 ptr[8] = ptr[9] = 0; // RDATA length is zero 2510 (*count)++; 2511 return(ptr + 10); 2512 } 2513 2514 mDNSexport mDNSu8 *putQuestion(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name, mDNSu16 rrtype, mDNSu16 rrclass) 2515 { 2516 ptr = putDomainNameAsLabels(msg, ptr, limit, name); 2517 if (!ptr || ptr+4 >= limit) return(mDNSNULL); // If we're out-of-space, return mDNSNULL 2518 ptr[0] = (mDNSu8)(rrtype >> 8); 2519 ptr[1] = (mDNSu8)(rrtype & 0xFF); 2520 ptr[2] = (mDNSu8)(rrclass >> 8); 2521 ptr[3] = (mDNSu8)(rrclass & 0xFF); 2522 msg->h.numQuestions++; 2523 return(ptr+4); 2524 } 2525 2526 // for dynamic updates 2527 mDNSexport mDNSu8 *putZone(DNSMessage *const msg, mDNSu8 *ptr, mDNSu8 *limit, const domainname *zone, mDNSOpaque16 zoneClass) 2528 { 2529 ptr = putDomainNameAsLabels(msg, ptr, limit, zone); 2530 if (!ptr || ptr + 4 > limit) return mDNSNULL; // If we're out-of-space, return NULL 2531 *ptr++ = (mDNSu8)(kDNSType_SOA >> 8); 2532 *ptr++ = (mDNSu8)(kDNSType_SOA & 0xFF); 2533 *ptr++ = zoneClass.b[0]; 2534 *ptr++ = zoneClass.b[1]; 2535 msg->h.mDNS_numZones++; 2536 return ptr; 2537 } 2538 2539 // for dynamic updates 2540 mDNSexport mDNSu8 *putPrereqNameNotInUse(const domainname *const name, DNSMessage *const msg, mDNSu8 *const ptr, mDNSu8 *const end) 2541 { 2542 AuthRecord prereq; 2543 mDNS_SetupResourceRecord(&prereq, mDNSNULL, mDNSInterface_Any, kDNSQType_ANY, kStandardTTL, 0, AuthRecordAny, mDNSNULL, mDNSNULL); 2544 AssignDomainName(&prereq.namestorage, name); 2545 prereq.resrec.rrtype = kDNSQType_ANY; 2546 prereq.resrec.rrclass = kDNSClass_NONE; 2547 return putEmptyResourceRecord(msg, ptr, end, &msg->h.mDNS_numPrereqs, &prereq); 2548 } 2549 2550 // for dynamic updates 2551 mDNSexport mDNSu8 *putDeletionRecord(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr) 2552 { 2553 // deletion: specify record w/ TTL 0, class NONE 2554 const mDNSu16 origclass = rr->rrclass; 2555 rr->rrclass = kDNSClass_NONE; 2556 ptr = PutResourceRecordTTLJumbo(msg, ptr, &msg->h.mDNS_numUpdates, rr, 0); 2557 rr->rrclass = origclass; 2558 return ptr; 2559 } 2560 2561 // for dynamic updates 2562 mDNSexport mDNSu8 *putDeletionRecordWithLimit(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr, mDNSu8 *limit) 2563 { 2564 // deletion: specify record w/ TTL 0, class NONE 2565 const mDNSu16 origclass = rr->rrclass; 2566 rr->rrclass = kDNSClass_NONE; 2567 ptr = PutResourceRecordTTLWithLimit(msg, ptr, &msg->h.mDNS_numUpdates, rr, 0, limit); 2568 rr->rrclass = origclass; 2569 return ptr; 2570 } 2571 2572 mDNSexport mDNSu8 *putDeleteRRSetWithLimit(DNSMessage *msg, mDNSu8 *ptr, const domainname *name, mDNSu16 rrtype, mDNSu8 *limit) 2573 { 2574 mDNSu16 class = kDNSQClass_ANY; 2575 2576 ptr = putDomainNameAsLabels(msg, ptr, limit, name); 2577 if (!ptr || ptr + 10 >= limit) return mDNSNULL; // If we're out-of-space, return mDNSNULL 2578 ptr[0] = (mDNSu8)(rrtype >> 8); 2579 ptr[1] = (mDNSu8)(rrtype & 0xFF); 2580 ptr[2] = (mDNSu8)(class >> 8); 2581 ptr[3] = (mDNSu8)(class & 0xFF); 2582 ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // zero ttl 2583 ptr[8] = ptr[9] = 0; // zero rdlength/rdata 2584 2585 msg->h.mDNS_numUpdates++; 2586 return ptr + 10; 2587 } 2588 2589 // for dynamic updates 2590 mDNSexport mDNSu8 *putDeleteAllRRSets(DNSMessage *msg, mDNSu8 *ptr, const domainname *name) 2591 { 2592 const mDNSu8 *limit = msg->data + AbsoluteMaxDNSMessageData; 2593 mDNSu16 class = kDNSQClass_ANY; 2594 mDNSu16 rrtype = kDNSQType_ANY; 2595 2596 ptr = putDomainNameAsLabels(msg, ptr, limit, name); 2597 if (!ptr || ptr + 10 >= limit) return mDNSNULL; // If we're out-of-space, return mDNSNULL 2598 ptr[0] = (mDNSu8)(rrtype >> 8); 2599 ptr[1] = (mDNSu8)(rrtype & 0xFF); 2600 ptr[2] = (mDNSu8)(class >> 8); 2601 ptr[3] = (mDNSu8)(class & 0xFF); 2602 ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // zero ttl 2603 ptr[8] = ptr[9] = 0; // zero rdlength/rdata 2604 2605 msg->h.mDNS_numUpdates++; 2606 return ptr + 10; 2607 } 2608 2609 // for dynamic updates 2610 mDNSexport mDNSu8 *putUpdateLease(DNSMessage *msg, mDNSu8 *end, mDNSu32 lease) 2611 { 2612 AuthRecord rr; 2613 mDNS_SetupResourceRecord(&rr, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); 2614 rr.resrec.rrclass = NormalMaxDNSMessageData; 2615 rr.resrec.rdlength = sizeof(rdataOPT); // One option in this OPT record 2616 rr.resrec.rdestimate = sizeof(rdataOPT); 2617 rr.resrec.rdata->u.opt[0].opt = kDNSOpt_Lease; 2618 rr.resrec.rdata->u.opt[0].u.updatelease = lease; 2619 end = PutResourceRecordTTLJumbo(msg, end, &msg->h.numAdditionals, &rr.resrec, 0); 2620 if (!end) { LogMsg("ERROR: putUpdateLease - PutResourceRecordTTL"); return mDNSNULL; } 2621 return end; 2622 } 2623 2624 // for dynamic updates 2625 mDNSexport mDNSu8 *putUpdateLeaseWithLimit(DNSMessage *msg, mDNSu8 *end, mDNSu32 lease, mDNSu8 *limit) 2626 { 2627 AuthRecord rr; 2628 mDNS_SetupResourceRecord(&rr, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); 2629 rr.resrec.rrclass = NormalMaxDNSMessageData; 2630 rr.resrec.rdlength = sizeof(rdataOPT); // One option in this OPT record 2631 rr.resrec.rdestimate = sizeof(rdataOPT); 2632 rr.resrec.rdata->u.opt[0].opt = kDNSOpt_Lease; 2633 rr.resrec.rdata->u.opt[0].u.updatelease = lease; 2634 end = PutResourceRecordTTLWithLimit(msg, end, &msg->h.numAdditionals, &rr.resrec, 0, limit); 2635 if (!end) { LogMsg("ERROR: putUpdateLease - PutResourceRecordTTLWithLimit"); return mDNSNULL; } 2636 return end; 2637 } 2638 2639 mDNSexport mDNSu8 *putDNSSECOption(DNSMessage *msg, mDNSu8 *end, mDNSu8 *limit) 2640 { 2641 AuthRecord rr; 2642 mDNSu32 ttl = 0; 2643 2644 mDNS_SetupResourceRecord(&rr, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); 2645 // It is still not clear what the right size is. We will have to fine tune this once we do 2646 // a lot of testing with DNSSEC. 2647 rr.resrec.rrclass = 4096; 2648 rr.resrec.rdlength = 0; 2649 rr.resrec.rdestimate = 0; 2650 // set the DO bit 2651 ttl |= 0x8000; 2652 end = PutResourceRecordTTLWithLimit(msg, end, &msg->h.numAdditionals, &rr.resrec, ttl, limit); 2653 if (!end) { LogMsg("ERROR: putUpdateLease - PutResourceRecordTTLWithLimit"); return mDNSNULL; } 2654 return end; 2655 } 2656 2657 mDNSexport mDNSu8 *putHINFO(const mDNS *const m, DNSMessage *const msg, mDNSu8 *end, DomainAuthInfo *authInfo, mDNSu8 *limit) 2658 { 2659 if (authInfo && authInfo->AutoTunnel) 2660 { 2661 AuthRecord hinfo; 2662 mDNSu8 *h = hinfo.rdatastorage.u.data; 2663 mDNSu16 len = 2 + m->HIHardware.c[0] + m->HISoftware.c[0]; 2664 mDNSu8 *newptr; 2665 mDNS_SetupResourceRecord(&hinfo, mDNSNULL, mDNSInterface_Any, kDNSType_HINFO, 0, kDNSRecordTypeUnique, AuthRecordAny, mDNSNULL, mDNSNULL); 2666 AppendDomainLabel(&hinfo.namestorage, &m->hostlabel); 2667 AppendDomainName (&hinfo.namestorage, &authInfo->domain); 2668 hinfo.resrec.rroriginalttl = 0; 2669 mDNSPlatformMemCopy(h, &m->HIHardware, 1 + (mDNSu32)m->HIHardware.c[0]); 2670 h += 1 + (int)h[0]; 2671 mDNSPlatformMemCopy(h, &m->HISoftware, 1 + (mDNSu32)m->HISoftware.c[0]); 2672 hinfo.resrec.rdlength = len; 2673 hinfo.resrec.rdestimate = len; 2674 newptr = PutResourceRecordTTLWithLimit(msg, end, &msg->h.numAdditionals, &hinfo.resrec, 0, limit); 2675 return newptr; 2676 } 2677 else 2678 return end; 2679 } 2680 2681 // *************************************************************************** 2682 #if COMPILER_LIKES_PRAGMA_MARK 2683 #pragma mark - 2684 #pragma mark - DNS Message Parsing Functions 2685 #endif 2686 2687 mDNSexport mDNSu32 DomainNameHashValue(const domainname *const name) 2688 { 2689 mDNSu32 sum = 0; 2690 const mDNSu8 *c; 2691 2692 for (c = name->c; c[0] != 0 && c[1] != 0; c += 2) 2693 { 2694 sum += ((mDNSIsUpperCase(c[0]) ? c[0] + 'a' - 'A' : c[0]) << 8) | 2695 (mDNSIsUpperCase(c[1]) ? c[1] + 'a' - 'A' : c[1]); 2696 sum = (sum<<3) | (sum>>29); 2697 } 2698 if (c[0]) sum += ((mDNSIsUpperCase(c[0]) ? c[0] + 'a' - 'A' : c[0]) << 8); 2699 return(sum); 2700 } 2701 2702 mDNSexport void SetNewRData(ResourceRecord *const rr, RData *NewRData, mDNSu16 rdlength) 2703 { 2704 domainname *target; 2705 if (NewRData) 2706 { 2707 rr->rdata = NewRData; 2708 rr->rdlength = rdlength; 2709 } 2710 // Must not try to get target pointer until after updating rr->rdata 2711 target = GetRRDomainNameTarget(rr); 2712 rr->rdlength = GetRDLength(rr, mDNSfalse); 2713 rr->rdestimate = GetRDLength(rr, mDNStrue); 2714 rr->rdatahash = target ? DomainNameHashValue(target) : RDataHashValue(rr); 2715 } 2716 2717 mDNSexport const mDNSu8 *skipDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end) 2718 { 2719 mDNSu16 total = 0; 2720 2721 if (ptr < (mDNSu8*)msg || ptr >= end) 2722 { debugf("skipDomainName: Illegal ptr not within packet boundaries"); return(mDNSNULL); } 2723 2724 while (1) // Read sequence of labels 2725 { 2726 const mDNSu8 len = *ptr++; // Read length of this label 2727 if (len == 0) return(ptr); // If length is zero, that means this name is complete 2728 switch (len & 0xC0) 2729 { 2730 case 0x00: if (ptr + len >= end) // Remember: expect at least one more byte for the root label 2731 { debugf("skipDomainName: Malformed domain name (overruns packet end)"); return(mDNSNULL); } 2732 if (total + 1 + len >= MAX_DOMAIN_NAME) // Remember: expect at least one more byte for the root label 2733 { debugf("skipDomainName: Malformed domain name (more than 256 characters)"); return(mDNSNULL); } 2734 ptr += len; 2735 total += 1 + len; 2736 break; 2737 2738 case 0x40: debugf("skipDomainName: Extended EDNS0 label types 0x%X not supported", len); return(mDNSNULL); 2739 case 0x80: debugf("skipDomainName: Illegal label length 0x%X", len); return(mDNSNULL); 2740 case 0xC0: return(ptr+1); 2741 } 2742 } 2743 } 2744 2745 // Routine to fetch an FQDN from the DNS message, following compression pointers if necessary. 2746 mDNSexport const mDNSu8 *getDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end, 2747 domainname *const name) 2748 { 2749 const mDNSu8 *nextbyte = mDNSNULL; // Record where we got to before we started following pointers 2750 mDNSu8 *np = name->c; // Name pointer 2751 const mDNSu8 *const limit = np + MAX_DOMAIN_NAME; // Limit so we don't overrun buffer 2752 2753 if (ptr < (mDNSu8*)msg || ptr >= end) 2754 { debugf("getDomainName: Illegal ptr not within packet boundaries"); return(mDNSNULL); } 2755 2756 *np = 0; // Tentatively place the root label here (may be overwritten if we have more labels) 2757 2758 while (1) // Read sequence of labels 2759 { 2760 const mDNSu8 len = *ptr++; // Read length of this label 2761 if (len == 0) break; // If length is zero, that means this name is complete 2762 switch (len & 0xC0) 2763 { 2764 int i; 2765 mDNSu16 offset; 2766 2767 case 0x00: if (ptr + len >= end) // Remember: expect at least one more byte for the root label 2768 { debugf("getDomainName: Malformed domain name (overruns packet end)"); return(mDNSNULL); } 2769 if (np + 1 + len >= limit) // Remember: expect at least one more byte for the root label 2770 { debugf("getDomainName: Malformed domain name (more than 256 characters)"); return(mDNSNULL); } 2771 *np++ = len; 2772 for (i=0; i<len; i++) *np++ = *ptr++; 2773 *np = 0; // Tentatively place the root label here (may be overwritten if we have more labels) 2774 break; 2775 2776 case 0x40: debugf("getDomainName: Extended EDNS0 label types 0x%X not supported in name %##s", len, name->c); 2777 return(mDNSNULL); 2778 2779 case 0x80: debugf("getDomainName: Illegal label length 0x%X in domain name %##s", len, name->c); return(mDNSNULL); 2780 2781 case 0xC0: offset = (mDNSu16)((((mDNSu16)(len & 0x3F)) << 8) | *ptr++); 2782 if (!nextbyte) nextbyte = ptr; // Record where we got to before we started following pointers 2783 ptr = (mDNSu8 *)msg + offset; 2784 if (ptr < (mDNSu8*)msg || ptr >= end) 2785 { debugf("getDomainName: Illegal compression pointer not within packet boundaries"); return(mDNSNULL); } 2786 if (*ptr & 0xC0) 2787 { debugf("getDomainName: Compression pointer must point to real label"); return(mDNSNULL); } 2788 break; 2789 } 2790 } 2791 2792 if (nextbyte) return(nextbyte); 2793 else return(ptr); 2794 } 2795 2796 mDNSexport const mDNSu8 *skipResourceRecord(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end) 2797 { 2798 mDNSu16 pktrdlength; 2799 2800 ptr = skipDomainName(msg, ptr, end); 2801 if (!ptr) { debugf("skipResourceRecord: Malformed RR name"); return(mDNSNULL); } 2802 2803 if (ptr + 10 > end) { debugf("skipResourceRecord: Malformed RR -- no type/class/ttl/len!"); return(mDNSNULL); } 2804 pktrdlength = (mDNSu16)((mDNSu16)ptr[8] << 8 | ptr[9]); 2805 ptr += 10; 2806 if (ptr + pktrdlength > end) { debugf("skipResourceRecord: RDATA exceeds end of packet"); return(mDNSNULL); } 2807 2808 return(ptr + pktrdlength); 2809 } 2810 2811 // Sanity check whether the NSEC/NSEC3 bitmap is good 2812 mDNSlocal mDNSu8 *SanityCheckBitMap(const mDNSu8 *bmap, const mDNSu8 *end, int len) 2813 { 2814 int win, wlen; 2815 2816 while (bmap < end) 2817 { 2818 if (len < 3) 2819 { 2820 LogInfo("SanityCheckBitMap: invalid length %d", len); 2821 return mDNSNULL; 2822 } 2823 2824 win = *bmap++; 2825 wlen = *bmap++; 2826 len -= 2; 2827 if (len < wlen || wlen < 1 || wlen > 32) 2828 { 2829 LogInfo("SanityCheckBitMap: invalid window length %d", wlen); 2830 return mDNSNULL; 2831 } 2832 if (win < 0 || win >= 256) 2833 { 2834 LogInfo("SanityCheckBitMap: invalid window %d", win); 2835 return mDNSNULL; 2836 } 2837 2838 bmap += wlen; 2839 len -= wlen; 2840 } 2841 return (mDNSu8 *)bmap; 2842 } 2843 2844 // This function is called with "msg" when we receive a DNS message and needs to parse a single resource record 2845 // pointed to by "ptr". Some resource records like SOA, SRV are converted to host order and also expanded 2846 // (domainnames are expanded to 255 bytes) when stored in memory. 2847 // 2848 // This function can also be called with "NULL" msg to parse a single resource record pointed to by ptr. 2849 // The caller can do this only if the names in the resource records are compressed and validity of the 2850 // resource record has already been done before. DNSSEC currently uses it this way. 2851 mDNSexport mDNSBool SetRData(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *end, 2852 LargeCacheRecord *const largecr, mDNSu16 rdlength) 2853 { 2854 CacheRecord *const rr = &largecr->r; 2855 RDataBody2 *const rdb = (RDataBody2 *)rr->smallrdatastorage.data; 2856 2857 switch (rr->resrec.rrtype) 2858 { 2859 case kDNSType_A: 2860 if (rdlength != sizeof(mDNSv4Addr)) 2861 goto fail; 2862 rdb->ipv4.b[0] = ptr[0]; 2863 rdb->ipv4.b[1] = ptr[1]; 2864 rdb->ipv4.b[2] = ptr[2]; 2865 rdb->ipv4.b[3] = ptr[3]; 2866 break; 2867 2868 case kDNSType_NS: 2869 case kDNSType_MD: 2870 case kDNSType_MF: 2871 case kDNSType_CNAME: 2872 case kDNSType_MB: 2873 case kDNSType_MG: 2874 case kDNSType_MR: 2875 case kDNSType_PTR: 2876 case kDNSType_NSAP_PTR: 2877 case kDNSType_DNAME: 2878 if (msg) 2879 { 2880 ptr = getDomainName(msg, ptr, end, &rdb->name); 2881 } 2882 else 2883 { 2884 AssignDomainName(&rdb->name, (domainname *)ptr); 2885 ptr += DomainNameLength(&rdb->name); 2886 } 2887 if (ptr != end) 2888 { 2889 debugf("SetRData: Malformed CNAME/PTR RDATA name"); 2890 goto fail; 2891 } 2892 break; 2893 2894 case kDNSType_SOA: 2895 if (msg) 2896 { 2897 ptr = getDomainName(msg, ptr, end, &rdb->soa.mname); 2898 } 2899 else 2900 { 2901 AssignDomainName(&rdb->soa.mname, (domainname *)ptr); 2902 ptr += DomainNameLength(&rdb->soa.mname); 2903 } 2904 if (!ptr) 2905 { 2906 debugf("SetRData: Malformed SOA RDATA mname"); 2907 goto fail; 2908 } 2909 if (msg) 2910 { 2911 ptr = getDomainName(msg, ptr, end, &rdb->soa.rname); 2912 } 2913 else 2914 { 2915 AssignDomainName(&rdb->soa.rname, (domainname *)ptr); 2916 ptr += DomainNameLength(&rdb->soa.rname); 2917 } 2918 if (!ptr) 2919 { 2920 debugf("SetRData: Malformed SOA RDATA rname"); 2921 goto fail; 2922 } 2923 if (ptr + 0x14 != end) 2924 { 2925 debugf("SetRData: Malformed SOA RDATA"); 2926 goto fail; 2927 } 2928 rdb->soa.serial = (mDNSs32) ((mDNSs32)ptr[0x00] << 24 | (mDNSs32)ptr[0x01] << 16 | (mDNSs32)ptr[0x02] << 8 | ptr[0x03]); 2929 rdb->soa.refresh = (mDNSu32) ((mDNSu32)ptr[0x04] << 24 | (mDNSu32)ptr[0x05] << 16 | (mDNSu32)ptr[0x06] << 8 | ptr[0x07]); 2930 rdb->soa.retry = (mDNSu32) ((mDNSu32)ptr[0x08] << 24 | (mDNSu32)ptr[0x09] << 16 | (mDNSu32)ptr[0x0A] << 8 | ptr[0x0B]); 2931 rdb->soa.expire = (mDNSu32) ((mDNSu32)ptr[0x0C] << 24 | (mDNSu32)ptr[0x0D] << 16 | (mDNSu32)ptr[0x0E] << 8 | ptr[0x0F]); 2932 rdb->soa.min = (mDNSu32) ((mDNSu32)ptr[0x10] << 24 | (mDNSu32)ptr[0x11] << 16 | (mDNSu32)ptr[0x12] << 8 | ptr[0x13]); 2933 break; 2934 2935 case kDNSType_NULL: 2936 case kDNSType_HINFO: 2937 case kDNSType_TXT: 2938 case kDNSType_X25: 2939 case kDNSType_ISDN: 2940 case kDNSType_LOC: 2941 case kDNSType_DHCID: 2942 rr->resrec.rdlength = rdlength; 2943 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 2944 break; 2945 2946 case kDNSType_MX: 2947 case kDNSType_AFSDB: 2948 case kDNSType_RT: 2949 case kDNSType_KX: 2950 // Preference + domainname 2951 if (rdlength < 3) 2952 goto fail; 2953 rdb->mx.preference = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); 2954 ptr += 2; 2955 if (msg) 2956 { 2957 ptr = getDomainName(msg, ptr, end, &rdb->mx.exchange); 2958 } 2959 else 2960 { 2961 AssignDomainName(&rdb->mx.exchange, (domainname *)ptr); 2962 ptr += DomainNameLength(&rdb->mx.exchange); 2963 } 2964 if (ptr != end) 2965 { 2966 debugf("SetRData: Malformed MX name"); 2967 goto fail; 2968 } 2969 break; 2970 2971 case kDNSType_MINFO: 2972 case kDNSType_RP: 2973 // Domainname + domainname 2974 if (msg) 2975 { 2976 ptr = getDomainName(msg, ptr, end, &rdb->rp.mbox); 2977 } 2978 else 2979 { 2980 AssignDomainName(&rdb->rp.mbox, (domainname *)ptr); 2981 ptr += DomainNameLength(&rdb->rp.mbox); 2982 } 2983 if (!ptr) 2984 { 2985 debugf("SetRData: Malformed RP mbox"); 2986 goto fail; 2987 } 2988 if (msg) 2989 { 2990 ptr = getDomainName(msg, ptr, end, &rdb->rp.txt); 2991 } 2992 else 2993 { 2994 AssignDomainName(&rdb->rp.txt, (domainname *)ptr); 2995 ptr += DomainNameLength(&rdb->rp.txt); 2996 } 2997 if (ptr != end) 2998 { 2999 debugf("SetRData: Malformed RP txt"); 3000 goto fail; 3001 } 3002 break; 3003 3004 case kDNSType_PX: 3005 // Preference + domainname + domainname 3006 if (rdlength < 4) 3007 goto fail; 3008 rdb->px.preference = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); 3009 ptr += 2; 3010 if (msg) 3011 { 3012 ptr = getDomainName(msg, ptr, end, &rdb->px.map822); 3013 } 3014 else 3015 { 3016 AssignDomainName(&rdb->px.map822, (domainname *)ptr); 3017 ptr += DomainNameLength(&rdb->px.map822); 3018 } 3019 if (!ptr) 3020 { 3021 debugf("SetRData: Malformed PX map822"); 3022 goto fail; 3023 } 3024 if (msg) 3025 { 3026 ptr = getDomainName(msg, ptr, end, &rdb->px.mapx400); 3027 } 3028 else 3029 { 3030 AssignDomainName(&rdb->px.mapx400, (domainname *)ptr); 3031 ptr += DomainNameLength(&rdb->px.mapx400); 3032 } 3033 if (ptr != end) 3034 { 3035 debugf("SetRData: Malformed PX mapx400"); 3036 goto fail; 3037 } 3038 break; 3039 3040 case kDNSType_AAAA: 3041 if (rdlength != sizeof(mDNSv6Addr)) 3042 goto fail; 3043 mDNSPlatformMemCopy(&rdb->ipv6, ptr, sizeof(rdb->ipv6)); 3044 break; 3045 3046 case kDNSType_SRV: 3047 // Priority + weight + port + domainname 3048 if (rdlength < 7) 3049 goto fail; 3050 rdb->srv.priority = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); 3051 rdb->srv.weight = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); 3052 rdb->srv.port.b[0] = ptr[4]; 3053 rdb->srv.port.b[1] = ptr[5]; 3054 ptr += 6; 3055 if (msg) 3056 { 3057 ptr = getDomainName(msg, ptr, end, &rdb->srv.target); 3058 } 3059 else 3060 { 3061 AssignDomainName(&rdb->srv.target, (domainname *)ptr); 3062 ptr += DomainNameLength(&rdb->srv.target); 3063 } 3064 if (ptr != end) 3065 { 3066 debugf("SetRData: Malformed SRV RDATA name"); 3067 goto fail; 3068 } 3069 break; 3070 3071 case kDNSType_NAPTR: 3072 { 3073 int savelen, len; 3074 domainname name; 3075 const mDNSu8 *orig = ptr; 3076 3077 // Make sure the data is parseable and within the limits. DNSSEC code looks at 3078 // the domain name in the end for a valid domainname. 3079 // 3080 // Fixed length: Order, preference (4 bytes) 3081 // Variable length: flags, service, regexp, domainname 3082 3083 if (rdlength < 8) 3084 goto fail; 3085 // Order, preference. 3086 ptr += 4; 3087 // Parse flags, Service and Regexp 3088 // length in the first byte does not include the length byte itself 3089 len = *ptr + 1; 3090 ptr += len; 3091 if (ptr >= end) 3092 { 3093 LogInfo("SetRData: Malformed NAPTR flags"); 3094 goto fail; 3095 } 3096 3097 // Service 3098 len = *ptr + 1; 3099 ptr += len; 3100 if (ptr >= end) 3101 { 3102 LogInfo("SetRData: Malformed NAPTR service"); 3103 goto fail; 3104 } 3105 3106 // Regexp 3107 len = *ptr + 1; 3108 ptr += len; 3109 if (ptr >= end) 3110 { 3111 LogInfo("SetRData: Malformed NAPTR regexp"); 3112 goto fail; 3113 } 3114 3115 savelen = ptr - orig; 3116 3117 // RFC 2915 states that name compression is not allowed for this field. But RFC 3597 3118 // states that for NAPTR we should decompress. We make sure that we store the full 3119 // name rather than the compressed name 3120 if (msg) 3121 { 3122 ptr = getDomainName(msg, ptr, end, &name); 3123 } 3124 else 3125 { 3126 AssignDomainName(&name, (domainname *)ptr); 3127 ptr += DomainNameLength(&name); 3128 } 3129 if (ptr != end) 3130 { 3131 LogInfo("SetRData: Malformed NAPTR RDATA name"); 3132 goto fail; 3133 } 3134 3135 rr->resrec.rdlength = savelen + DomainNameLength(&name); 3136 // The uncompressed size should not exceed the limits 3137 if (rr->resrec.rdlength > MaximumRDSize) 3138 { 3139 LogInfo("SetRData: Malformed NAPTR rdlength %d, rr->resrec.rdlength %d, " 3140 "bmaplen %d, name %##s", rdlength, rr->resrec.rdlength, name.c); 3141 goto fail; 3142 } 3143 mDNSPlatformMemCopy(rdb->data, orig, savelen); 3144 AssignDomainName((domainname *)(rdb->data + savelen), &name); 3145 break; 3146 } 3147 case kDNSType_OPT: { 3148 mDNSu8 *dataend = rr->resrec.rdata->u.data; 3149 rdataOPT *opt = rr->resrec.rdata->u.opt; 3150 rr->resrec.rdlength = 0; 3151 while (ptr < end && (mDNSu8 *)(opt+1) < &dataend[MaximumRDSize]) 3152 { 3153 const rdataOPT *const currentopt = opt; 3154 if (ptr + 4 > end) { LogInfo("SetRData: OPT RDATA ptr + 4 > end"); goto fail; } 3155 opt->opt = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); 3156 opt->optlen = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); 3157 ptr += 4; 3158 if (ptr + opt->optlen > end) { LogInfo("SetRData: ptr + opt->optlen > end"); goto fail; } 3159 switch (opt->opt) 3160 { 3161 case kDNSOpt_LLQ: 3162 if (opt->optlen == DNSOpt_LLQData_Space - 4) 3163 { 3164 opt->u.llq.vers = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); 3165 opt->u.llq.llqOp = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); 3166 opt->u.llq.err = (mDNSu16)((mDNSu16)ptr[4] << 8 | ptr[5]); 3167 mDNSPlatformMemCopy(opt->u.llq.id.b, ptr+6, 8); 3168 opt->u.llq.llqlease = (mDNSu32) ((mDNSu32)ptr[14] << 24 | (mDNSu32)ptr[15] << 16 | (mDNSu32)ptr[16] << 8 | ptr[17]); 3169 if (opt->u.llq.llqlease > 0x70000000UL / mDNSPlatformOneSecond) 3170 opt->u.llq.llqlease = 0x70000000UL / mDNSPlatformOneSecond; 3171 opt++; 3172 } 3173 break; 3174 case kDNSOpt_Lease: 3175 if (opt->optlen == DNSOpt_LeaseData_Space - 4) 3176 { 3177 opt->u.updatelease = (mDNSu32) ((mDNSu32)ptr[0] << 24 | (mDNSu32)ptr[1] << 16 | (mDNSu32)ptr[2] << 8 | ptr[3]); 3178 if (opt->u.updatelease > 0x70000000UL / mDNSPlatformOneSecond) 3179 opt->u.updatelease = 0x70000000UL / mDNSPlatformOneSecond; 3180 opt++; 3181 } 3182 break; 3183 case kDNSOpt_Owner: 3184 if (ValidOwnerLength(opt->optlen)) 3185 { 3186 opt->u.owner.vers = ptr[0]; 3187 opt->u.owner.seq = ptr[1]; 3188 mDNSPlatformMemCopy(opt->u.owner.HMAC.b, ptr+2, 6); // 6-byte MAC address 3189 mDNSPlatformMemCopy(opt->u.owner.IMAC.b, ptr+2, 6); // 6-byte MAC address 3190 opt->u.owner.password = zeroEthAddr; 3191 if (opt->optlen >= DNSOpt_OwnerData_ID_Wake_Space-4) 3192 { 3193 mDNSPlatformMemCopy(opt->u.owner.IMAC.b, ptr+8, 6); // 6-byte MAC address 3194 // This mDNSPlatformMemCopy is safe because the ValidOwnerLength(opt->optlen) check above 3195 // ensures that opt->optlen is no more than DNSOpt_OwnerData_ID_Wake_PW6_Space - 4 3196 if (opt->optlen > DNSOpt_OwnerData_ID_Wake_Space-4) 3197 mDNSPlatformMemCopy(opt->u.owner.password.b, ptr+14, opt->optlen - (DNSOpt_OwnerData_ID_Wake_Space-4)); 3198 } 3199 opt++; 3200 } 3201 break; 3202 case kDNSOpt_Trace: 3203 if (opt->optlen == DNSOpt_TraceData_Space - 4) 3204 { 3205 opt->u.tracer.platf = ptr[0]; 3206 opt->u.tracer.mDNSv = (mDNSu32) ((mDNSu32)ptr[1] << 24 | (mDNSu32)ptr[2] << 16 | (mDNSu32)ptr[3] << 8 | ptr[4]); 3207 opt++; 3208 } 3209 else 3210 { 3211 opt->u.tracer.platf = 0xFF; 3212 opt->u.tracer.mDNSv = 0xFFFFFFFF; 3213 opt++; 3214 } 3215 break; 3216 } 3217 ptr += currentopt->optlen; 3218 } 3219 rr->resrec.rdlength = (mDNSu16)((mDNSu8*)opt - rr->resrec.rdata->u.data); 3220 if (ptr != end) { LogInfo("SetRData: Malformed OptRdata"); goto fail; } 3221 break; 3222 } 3223 3224 case kDNSType_NSEC: { 3225 domainname name; 3226 int len = rdlength; 3227 int bmaplen, dlen; 3228 const mDNSu8 *orig = ptr; 3229 const mDNSu8 *bmap; 3230 3231 if (msg) 3232 { 3233 ptr = getDomainName(msg, ptr, end, &name); 3234 } 3235 else 3236 { 3237 AssignDomainName(&name, (domainname *)ptr); 3238 ptr += DomainNameLength(&name); 3239 } 3240 if (!ptr) 3241 { 3242 LogInfo("SetRData: Malformed NSEC nextname"); 3243 goto fail; 3244 } 3245 3246 dlen = DomainNameLength(&name); 3247 3248 // Multicast NSECs use name compression for this field unlike the unicast case which 3249 // does not use compression. And multicast case always succeeds in compression. So, 3250 // the rdlength includes only the compressed space in that case. So, can't 3251 // use the DomainNameLength of name to reduce the length here. 3252 len -= (ptr - orig); 3253 bmaplen = len; // Save the length of the bitmap 3254 bmap = ptr; 3255 ptr = SanityCheckBitMap(bmap, end, len); 3256 if (!ptr) 3257 goto fail; 3258 if (ptr != end) 3259 { 3260 LogInfo("SetRData: Malformed NSEC length not right"); 3261 goto fail; 3262 } 3263 3264 // Initialize the right length here. When we call SetNewRData below which in turn calls 3265 // GetRDLength and for NSEC case, it assumes that rdlength is intitialized 3266 rr->resrec.rdlength = DomainNameLength(&name) + bmaplen; 3267 3268 // Do we have space after the name expansion ? 3269 if (rr->resrec.rdlength > MaximumRDSize) 3270 { 3271 LogInfo("SetRData: Malformed NSEC rdlength %d, rr->resrec.rdlength %d, " 3272 "bmaplen %d, name %##s", rdlength, rr->resrec.rdlength, name.c); 3273 goto fail; 3274 } 3275 AssignDomainName((domainname *)rdb->data, &name); 3276 mDNSPlatformMemCopy(rdb->data + dlen, bmap, bmaplen); 3277 break; 3278 } 3279 case kDNSType_NSEC3: 3280 { 3281 rdataNSEC3 *nsec3 = (rdataNSEC3 *)ptr; 3282 mDNSu8 *p = (mDNSu8 *)&nsec3->salt; 3283 int hashLength, bitmaplen; 3284 3285 if (rdlength < NSEC3_FIXED_SIZE + 1) 3286 { 3287 LogInfo("SetRData: NSEC3 too small length %d", rdlength); 3288 goto fail; 3289 } 3290 if (nsec3->alg != SHA1_DIGEST_TYPE) 3291 { 3292 LogInfo("SetRData: nsec3 alg %d not supported", nsec3->alg); 3293 goto fail; 3294 } 3295 if (swap16(nsec3->iterations) > NSEC3_MAX_ITERATIONS) 3296 { 3297 LogInfo("SetRData: nsec3 iteration count %d too big", swap16(nsec3->iterations)); 3298 goto fail; 3299 } 3300 p += nsec3->saltLength; 3301 // There should at least be one byte beyond saltLength 3302 if (p >= end) 3303 { 3304 LogInfo("SetRData: nsec3 too small, at saltlength %d, p %p, end %p", nsec3->saltLength, p, end); 3305 goto fail; 3306 } 3307 // p is pointing at hashLength 3308 hashLength = (int)*p++; 3309 if (!hashLength) 3310 { 3311 LogInfo("SetRData: hashLength zero"); 3312 goto fail; 3313 } 3314 p += hashLength; 3315 if (p > end) 3316 { 3317 LogInfo("SetRData: nsec3 too small, at hashLength %d, p %p, end %p", hashLength, p, end); 3318 goto fail; 3319 } 3320 3321 bitmaplen = rdlength - (int)(p - ptr); 3322 p = SanityCheckBitMap(p, end, bitmaplen); 3323 if (!p) 3324 goto fail; 3325 rr->resrec.rdlength = rdlength; 3326 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 3327 break; 3328 } 3329 case kDNSType_TKEY: 3330 case kDNSType_TSIG: 3331 { 3332 domainname name; 3333 int dlen, rlen; 3334 3335 // The name should not be compressed. But we take the conservative approach 3336 // and uncompress the name before we store it. 3337 if (msg) 3338 { 3339 ptr = getDomainName(msg, ptr, end, &name); 3340 } 3341 else 3342 { 3343 AssignDomainName(&name, (domainname *)ptr); 3344 ptr += DomainNameLength(&name); 3345 } 3346 if (!ptr) 3347 { 3348 LogInfo("SetRData: Malformed name for TSIG/TKEY type %d", rr->resrec.rrtype); 3349 goto fail; 3350 } 3351 dlen = DomainNameLength(&name); 3352 rlen = end - ptr; 3353 rr->resrec.rdlength = dlen + rlen; 3354 AssignDomainName((domainname *)rdb->data, &name); 3355 mDNSPlatformMemCopy(rdb->data + dlen, ptr, rlen); 3356 break; 3357 } 3358 case kDNSType_RRSIG: 3359 { 3360 const mDNSu8 *sig = ptr + RRSIG_FIXED_SIZE; 3361 const mDNSu8 *orig = sig; 3362 domainname name; 3363 if (rdlength < RRSIG_FIXED_SIZE + 1) 3364 { 3365 LogInfo("SetRData: RRSIG too small length %d", rdlength); 3366 goto fail; 3367 } 3368 if (msg) 3369 { 3370 sig = getDomainName(msg, sig, end, &name); 3371 } 3372 else 3373 { 3374 AssignDomainName(&name, (domainname *)sig); 3375 sig += DomainNameLength(&name); 3376 } 3377 if (!sig) 3378 { 3379 LogInfo("SetRData: Malformed RRSIG record"); 3380 goto fail; 3381 } 3382 3383 if ((sig - orig) != DomainNameLength(&name)) 3384 { 3385 LogInfo("SetRData: Malformed RRSIG record, signer name compression"); 3386 goto fail; 3387 } 3388 // Just ensure that we have at least one byte of the signature 3389 if (sig + 1 >= end) 3390 { 3391 LogInfo("SetRData: Not enough bytes for signature type %d", rr->resrec.rrtype); 3392 goto fail; 3393 } 3394 rr->resrec.rdlength = rdlength; 3395 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 3396 break; 3397 } 3398 case kDNSType_DNSKEY: 3399 { 3400 if (rdlength < DNSKEY_FIXED_SIZE + 1) 3401 { 3402 LogInfo("SetRData: DNSKEY too small length %d", rdlength); 3403 goto fail; 3404 } 3405 rr->resrec.rdlength = rdlength; 3406 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 3407 break; 3408 } 3409 case kDNSType_DS: 3410 { 3411 if (rdlength < DS_FIXED_SIZE + 1) 3412 { 3413 LogInfo("SetRData: DS too small length %d", rdlength); 3414 goto fail; 3415 } 3416 rr->resrec.rdlength = rdlength; 3417 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 3418 break; 3419 } 3420 default: 3421 debugf("SetRData: Warning! Reading resource type %d (%s) as opaque data", 3422 rr->resrec.rrtype, DNSTypeName(rr->resrec.rrtype)); 3423 // Note: Just because we don't understand the record type, that doesn't 3424 // mean we fail. The DNS protocol specifies rdlength, so we can 3425 // safely skip over unknown records and ignore them. 3426 // We also grab a binary copy of the rdata anyway, since the caller 3427 // might know how to interpret it even if we don't. 3428 rr->resrec.rdlength = rdlength; 3429 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 3430 break; 3431 } 3432 return mDNStrue; 3433 fail: 3434 return mDNSfalse; 3435 } 3436 3437 mDNSexport const mDNSu8 *GetLargeResourceRecord(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *ptr, 3438 const mDNSu8 *end, const mDNSInterfaceID InterfaceID, mDNSu8 RecordType, LargeCacheRecord *const largecr) 3439 { 3440 CacheRecord *const rr = &largecr->r; 3441 mDNSu16 pktrdlength; 3442 3443 if (largecr == &m->rec && m->rec.r.resrec.RecordType) 3444 { 3445 LogMsg("GetLargeResourceRecord: m->rec appears to be already in use for %s", CRDisplayString(m, &m->rec.r)); 3446 #if ForceAlerts 3447 *(long*)0 = 0; 3448 #endif 3449 } 3450 3451 rr->next = mDNSNULL; 3452 rr->resrec.name = &largecr->namestorage; 3453 3454 rr->NextInKAList = mDNSNULL; 3455 rr->TimeRcvd = m ? m->timenow : 0; 3456 rr->DelayDelivery = 0; 3457 rr->NextRequiredQuery = m ? m->timenow : 0; // Will be updated to the real value when we call SetNextCacheCheckTimeForRecord() 3458 rr->LastUsed = m ? m->timenow : 0; 3459 rr->CRActiveQuestion = mDNSNULL; 3460 rr->UnansweredQueries = 0; 3461 rr->LastUnansweredTime= 0; 3462 #if ENABLE_MULTI_PACKET_QUERY_SNOOPING 3463 rr->MPUnansweredQ = 0; 3464 rr->MPLastUnansweredQT= 0; 3465 rr->MPUnansweredKA = 0; 3466 rr->MPExpectingKA = mDNSfalse; 3467 #endif 3468 rr->NextInCFList = mDNSNULL; 3469 3470 rr->resrec.InterfaceID = InterfaceID; 3471 rr->resrec.rDNSServer = mDNSNULL; 3472 3473 ptr = getDomainName(msg, ptr, end, &largecr->namestorage); // Will bail out correctly if ptr is NULL 3474 if (!ptr) { debugf("GetLargeResourceRecord: Malformed RR name"); return(mDNSNULL); } 3475 rr->resrec.namehash = DomainNameHashValue(rr->resrec.name); 3476 3477 if (ptr + 10 > end) { debugf("GetLargeResourceRecord: Malformed RR -- no type/class/ttl/len!"); return(mDNSNULL); } 3478 3479 rr->resrec.rrtype = (mDNSu16) ((mDNSu16)ptr[0] << 8 | ptr[1]); 3480 rr->resrec.rrclass = (mDNSu16)(((mDNSu16)ptr[2] << 8 | ptr[3]) & kDNSClass_Mask); 3481 rr->resrec.rroriginalttl = (mDNSu32) ((mDNSu32)ptr[4] << 24 | (mDNSu32)ptr[5] << 16 | (mDNSu32)ptr[6] << 8 | ptr[7]); 3482 if (rr->resrec.rroriginalttl > 0x70000000UL / mDNSPlatformOneSecond && (mDNSs32)rr->resrec.rroriginalttl != -1) 3483 rr->resrec.rroriginalttl = 0x70000000UL / mDNSPlatformOneSecond; 3484 // Note: We don't have to adjust m->NextCacheCheck here -- this is just getting a record into memory for 3485 // us to look at. If we decide to copy it into the cache, then we'll update m->NextCacheCheck accordingly. 3486 pktrdlength = (mDNSu16)((mDNSu16)ptr[8] << 8 | ptr[9]); 3487 3488 // If mDNS record has cache-flush bit set, we mark it unique 3489 // For uDNS records, all are implicitly deemed unique (a single DNS server is always 3490 // authoritative for the entire RRSet), unless this is a truncated response 3491 if (ptr[2] & (kDNSClass_UniqueRRSet >> 8) || (!InterfaceID && !(msg->h.flags.b[0] & kDNSFlag0_TC))) 3492 RecordType |= kDNSRecordTypePacketUniqueMask; 3493 ptr += 10; 3494 if (ptr + pktrdlength > end) { debugf("GetLargeResourceRecord: RDATA exceeds end of packet"); return(mDNSNULL); } 3495 end = ptr + pktrdlength; // Adjust end to indicate the end of the rdata for this resource record 3496 3497 rr->resrec.rdata = (RData*)&rr->smallrdatastorage; 3498 rr->resrec.rdata->MaxRDLength = MaximumRDSize; 3499 3500 if (pktrdlength > MaximumRDSize) 3501 { 3502 LogInfo("GetLargeResourceRecord: %s rdata size (%d) exceeds storage (%d)", 3503 DNSTypeName(rr->resrec.rrtype), pktrdlength, rr->resrec.rdata->MaxRDLength); 3504 goto fail; 3505 } 3506 3507 if (!RecordType) LogMsg("GetLargeResourceRecord: No RecordType for %##s", rr->resrec.name->c); 3508 3509 // IMPORTANT: Any record type we understand and unpack into a structure containing domainnames needs to have corresponding 3510 // cases in SameRDataBody() and RDataHashValue() to do a semantic comparison (or checksum) of the structure instead of a blind 3511 // bitwise memory compare (or sum). This is because a domainname is a fixed size structure holding variable-length data. 3512 // Any bytes past the logical end of the name are undefined, and a blind bitwise memory compare may indicate that 3513 // two domainnames are different when semantically they are the same name and it's only the unused bytes that differ. 3514 if (rr->resrec.rrclass == kDNSQClass_ANY && pktrdlength == 0) // Used in update packets to mean "Delete An RRset" (RFC 2136) 3515 rr->resrec.rdlength = 0; 3516 else if (!SetRData(msg, ptr, end, largecr, pktrdlength)) 3517 goto fail; 3518 3519 SetNewRData(&rr->resrec, mDNSNULL, 0); // Sets rdlength, rdestimate, rdatahash for us 3520 3521 // Success! Now fill in RecordType to show this record contains valid data 3522 rr->resrec.RecordType = RecordType; 3523 return(end); 3524 3525 fail: 3526 // If we were unable to parse the rdata in this record, we indicate that by 3527 // returing a 'kDNSRecordTypePacketNegative' record with rdlength set to zero 3528 rr->resrec.RecordType = kDNSRecordTypePacketNegative; 3529 rr->resrec.rdlength = 0; 3530 rr->resrec.rdestimate = 0; 3531 rr->resrec.rdatahash = 0; 3532 return(end); 3533 } 3534 3535 mDNSexport const mDNSu8 *skipQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end) 3536 { 3537 ptr = skipDomainName(msg, ptr, end); 3538 if (!ptr) { debugf("skipQuestion: Malformed domain name in DNS question section"); return(mDNSNULL); } 3539 if (ptr+4 > end) { debugf("skipQuestion: Malformed DNS question section -- no query type and class!"); return(mDNSNULL); } 3540 return(ptr+4); 3541 } 3542 3543 mDNSexport const mDNSu8 *getQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end, const mDNSInterfaceID InterfaceID, 3544 DNSQuestion *question) 3545 { 3546 mDNSPlatformMemZero(question, sizeof(*question)); 3547 question->InterfaceID = InterfaceID; 3548 if (!InterfaceID) question->TargetQID = onesID; // In DNSQuestions we use TargetQID as the indicator of whether it's unicast or multicast 3549 ptr = getDomainName(msg, ptr, end, &question->qname); 3550 if (!ptr) { debugf("Malformed domain name in DNS question section"); return(mDNSNULL); } 3551 if (ptr+4 > end) { debugf("Malformed DNS question section -- no query type and class!"); return(mDNSNULL); } 3552 3553 question->qnamehash = DomainNameHashValue(&question->qname); 3554 question->qtype = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); // Get type 3555 question->qclass = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); // and class 3556 return(ptr+4); 3557 } 3558 3559 mDNSexport const mDNSu8 *LocateAnswers(const DNSMessage *const msg, const mDNSu8 *const end) 3560 { 3561 int i; 3562 const mDNSu8 *ptr = msg->data; 3563 for (i = 0; i < msg->h.numQuestions && ptr; i++) ptr = skipQuestion(msg, ptr, end); 3564 return(ptr); 3565 } 3566 3567 mDNSexport const mDNSu8 *LocateAuthorities(const DNSMessage *const msg, const mDNSu8 *const end) 3568 { 3569 int i; 3570 const mDNSu8 *ptr = LocateAnswers(msg, end); 3571 for (i = 0; i < msg->h.numAnswers && ptr; i++) ptr = skipResourceRecord(msg, ptr, end); 3572 return(ptr); 3573 } 3574 3575 mDNSexport const mDNSu8 *LocateAdditionals(const DNSMessage *const msg, const mDNSu8 *const end) 3576 { 3577 int i; 3578 const mDNSu8 *ptr = LocateAuthorities(msg, end); 3579 for (i = 0; i < msg->h.numAuthorities; i++) ptr = skipResourceRecord(msg, ptr, end); 3580 return (ptr); 3581 } 3582 3583 mDNSexport const mDNSu8 *LocateOptRR(const DNSMessage *const msg, const mDNSu8 *const end, int minsize) 3584 { 3585 int i; 3586 const mDNSu8 *ptr = LocateAdditionals(msg, end); 3587 3588 // Locate the OPT record. 3589 // According to RFC 2671, "One OPT pseudo-RR can be added to the additional data section of either a request or a response." 3590 // This implies that there may be *at most* one OPT record per DNS message, in the Additional Section, 3591 // but not necessarily the *last* entry in the Additional Section. 3592 for (i = 0; ptr && i < msg->h.numAdditionals; i++) 3593 { 3594 if (ptr + DNSOpt_Header_Space + minsize <= end && // Make sure we have 11+minsize bytes of data 3595 ptr[0] == 0 && // Name must be root label 3596 ptr[1] == (kDNSType_OPT >> 8 ) && // rrtype OPT 3597 ptr[2] == (kDNSType_OPT & 0xFF) && 3598 ((mDNSu16)ptr[9] << 8 | (mDNSu16)ptr[10]) >= (mDNSu16)minsize) 3599 return(ptr); 3600 else 3601 ptr = skipResourceRecord(msg, ptr, end); 3602 } 3603 return(mDNSNULL); 3604 } 3605 3606 // On success, GetLLQOptData returns pointer to storage within shared "m->rec"; 3607 // it is caller's responsibilty to clear m->rec.r.resrec.RecordType after use 3608 // Note: An OPT RDataBody actually contains one or more variable-length rdataOPT objects packed together 3609 // The code that currently calls this assumes there's only one, instead of iterating through the set 3610 mDNSexport const rdataOPT *GetLLQOptData(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end) 3611 { 3612 const mDNSu8 *ptr = LocateOptRR(msg, end, DNSOpt_LLQData_Space); 3613 if (ptr) 3614 { 3615 ptr = GetLargeResourceRecord(m, msg, ptr, end, 0, kDNSRecordTypePacketAdd, &m->rec); 3616 if (ptr && m->rec.r.resrec.RecordType != kDNSRecordTypePacketNegative) return(&m->rec.r.resrec.rdata->u.opt[0]); 3617 } 3618 return(mDNSNULL); 3619 } 3620 3621 // Get the lease life of records in a dynamic update 3622 // returns 0 on error or if no lease present 3623 mDNSexport mDNSu32 GetPktLease(mDNS *m, DNSMessage *msg, const mDNSu8 *end) 3624 { 3625 mDNSu32 result = 0; 3626 const mDNSu8 *ptr = LocateOptRR(msg, end, DNSOpt_LeaseData_Space); 3627 if (ptr) ptr = GetLargeResourceRecord(m, msg, ptr, end, 0, kDNSRecordTypePacketAdd, &m->rec); 3628 if (ptr && m->rec.r.resrec.rdlength >= DNSOpt_LeaseData_Space && m->rec.r.resrec.rdata->u.opt[0].opt == kDNSOpt_Lease) 3629 result = m->rec.r.resrec.rdata->u.opt[0].u.updatelease; 3630 m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it 3631 return(result); 3632 } 3633 3634 mDNSlocal const mDNSu8 *DumpRecords(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end, int count, char *label) 3635 { 3636 int i; 3637 LogMsg("%2d %s", count, label); 3638 for (i = 0; i < count && ptr; i++) 3639 { 3640 // This puts a LargeCacheRecord on the stack instead of using the shared m->rec storage, 3641 // but since it's only used for debugging (and probably only on OS X, not on 3642 // embedded systems) putting a 9kB object on the stack isn't a big problem. 3643 LargeCacheRecord largecr; 3644 ptr = GetLargeResourceRecord(m, msg, ptr, end, mDNSInterface_Any, kDNSRecordTypePacketAns, &largecr); 3645 if (ptr) LogMsg("%2d TTL%8d %s", i, largecr.r.resrec.rroriginalttl, CRDisplayString(m, &largecr.r)); 3646 } 3647 if (!ptr) LogMsg("DumpRecords: ERROR: Premature end of packet data"); 3648 return(ptr); 3649 } 3650 3651 #define DNS_OP_Name(X) ( \ 3652 (X) == kDNSFlag0_OP_StdQuery ? "" : \ 3653 (X) == kDNSFlag0_OP_Iquery ? "Iquery " : \ 3654 (X) == kDNSFlag0_OP_Status ? "Status " : \ 3655 (X) == kDNSFlag0_OP_Unused3 ? "Unused3 " : \ 3656 (X) == kDNSFlag0_OP_Notify ? "Notify " : \ 3657 (X) == kDNSFlag0_OP_Update ? "Update " : "?? " ) 3658 3659 #define DNS_RC_Name(X) ( \ 3660 (X) == kDNSFlag1_RC_NoErr ? "NoErr" : \ 3661 (X) == kDNSFlag1_RC_FormErr ? "FormErr" : \ 3662 (X) == kDNSFlag1_RC_ServFail ? "ServFail" : \ 3663 (X) == kDNSFlag1_RC_NXDomain ? "NXDomain" : \ 3664 (X) == kDNSFlag1_RC_NotImpl ? "NotImpl" : \ 3665 (X) == kDNSFlag1_RC_Refused ? "Refused" : \ 3666 (X) == kDNSFlag1_RC_YXDomain ? "YXDomain" : \ 3667 (X) == kDNSFlag1_RC_YXRRSet ? "YXRRSet" : \ 3668 (X) == kDNSFlag1_RC_NXRRSet ? "NXRRSet" : \ 3669 (X) == kDNSFlag1_RC_NotAuth ? "NotAuth" : \ 3670 (X) == kDNSFlag1_RC_NotZone ? "NotZone" : "??" ) 3671 3672 // Note: DumpPacket expects the packet header fields in host byte order, not network byte order 3673 mDNSexport void DumpPacket(mDNS *const m, mStatus status, mDNSBool sent, char *transport, 3674 const mDNSAddr *srcaddr, mDNSIPPort srcport, 3675 const mDNSAddr *dstaddr, mDNSIPPort dstport, const DNSMessage *const msg, const mDNSu8 *const end) 3676 { 3677 mDNSBool IsUpdate = ((msg->h.flags.b[0] & kDNSFlag0_OP_Mask) == kDNSFlag0_OP_Update); 3678 const mDNSu8 *ptr = msg->data; 3679 int i; 3680 DNSQuestion q; 3681 char tbuffer[64], sbuffer[64], dbuffer[64] = ""; 3682 if (!status) tbuffer[mDNS_snprintf(tbuffer, sizeof(tbuffer), sent ? "Sent" : "Received" )] = 0; 3683 else tbuffer[mDNS_snprintf(tbuffer, sizeof(tbuffer), "ERROR %d %sing", status, sent ? "Send" : "Receive")] = 0; 3684 if (sent) sbuffer[mDNS_snprintf(sbuffer, sizeof(sbuffer), "port " )] = 0; 3685 else sbuffer[mDNS_snprintf(sbuffer, sizeof(sbuffer), "%#a:", srcaddr)] = 0; 3686 if (dstaddr || !mDNSIPPortIsZero(dstport)) 3687 dbuffer[mDNS_snprintf(dbuffer, sizeof(dbuffer), " to %#a:%d", dstaddr, mDNSVal16(dstport))] = 0; 3688 3689 LogMsg("-- %s %s DNS %s%s (flags %02X%02X) RCODE: %s (%d) %s%s%s%s%s%sID: %d %d bytes from %s%d%s%s --", 3690 tbuffer, transport, 3691 DNS_OP_Name(msg->h.flags.b[0] & kDNSFlag0_OP_Mask), 3692 msg->h.flags.b[0] & kDNSFlag0_QR_Response ? "Response" : "Query", 3693 msg->h.flags.b[0], msg->h.flags.b[1], 3694 DNS_RC_Name(msg->h.flags.b[1] & kDNSFlag1_RC_Mask), 3695 msg->h.flags.b[1] & kDNSFlag1_RC_Mask, 3696 msg->h.flags.b[0] & kDNSFlag0_AA ? "AA " : "", 3697 msg->h.flags.b[0] & kDNSFlag0_TC ? "TC " : "", 3698 msg->h.flags.b[0] & kDNSFlag0_RD ? "RD " : "", 3699 msg->h.flags.b[1] & kDNSFlag1_RA ? "RA " : "", 3700 msg->h.flags.b[1] & kDNSFlag1_AD ? "AD " : "", 3701 msg->h.flags.b[1] & kDNSFlag1_CD ? "CD " : "", 3702 mDNSVal16(msg->h.id), 3703 end - msg->data, 3704 sbuffer, mDNSVal16(srcport), dbuffer, 3705 (msg->h.flags.b[0] & kDNSFlag0_TC) ? " (truncated)" : "" 3706 ); 3707 3708 LogMsg("%2d %s", msg->h.numQuestions, IsUpdate ? "Zone" : "Questions"); 3709 for (i = 0; i < msg->h.numQuestions && ptr; i++) 3710 { 3711 ptr = getQuestion(msg, ptr, end, mDNSInterface_Any, &q); 3712 if (ptr) LogMsg("%2d %##s %s", i, q.qname.c, DNSTypeName(q.qtype)); 3713 } 3714 ptr = DumpRecords(m, msg, ptr, end, msg->h.numAnswers, IsUpdate ? "Prerequisites" : "Answers"); 3715 ptr = DumpRecords(m, msg, ptr, end, msg->h.numAuthorities, IsUpdate ? "Updates" : "Authorities"); 3716 ptr = DumpRecords(m, msg, ptr, end, msg->h.numAdditionals, "Additionals"); 3717 LogMsg("--------------"); 3718 } 3719 3720 // *************************************************************************** 3721 #if COMPILER_LIKES_PRAGMA_MARK 3722 #pragma mark - 3723 #pragma mark - Packet Sending Functions 3724 #endif 3725 3726 // Stub definition of TCPSocket_struct so we can access flags field. (Rest of TCPSocket_struct is platform-dependent.) 3727 struct TCPSocket_struct { TCPSocketFlags flags; /* ... */ }; 3728 3729 struct UDPSocket_struct 3730 { 3731 mDNSIPPort port; // MUST BE FIRST FIELD -- mDNSCoreReceive expects every UDPSocket_struct to begin with mDNSIPPort port 3732 }; 3733 3734 // Note: When we sign a DNS message using DNSDigest_SignMessage(), the current real-time clock value is used, which 3735 // is why we generally defer signing until we send the message, to ensure the signature is as fresh as possible. 3736 mDNSexport mStatus mDNSSendDNSMessage(mDNS *const m, DNSMessage *const msg, mDNSu8 *end, 3737 mDNSInterfaceID InterfaceID, UDPSocket *src, const mDNSAddr *dst, 3738 mDNSIPPort dstport, TCPSocket *sock, DomainAuthInfo *authInfo, 3739 mDNSBool useBackgroundTrafficClass) 3740 { 3741 mStatus status = mStatus_NoError; 3742 const mDNSu16 numAdditionals = msg->h.numAdditionals; 3743 mDNSu8 *newend; 3744 mDNSu8 *limit = msg->data + AbsoluteMaxDNSMessageData; 3745 3746 #if APPLE_OSX_mDNSResponder 3747 // maintain outbound packet statistics 3748 if (mDNSOpaque16IsZero(msg->h.id)) 3749 m->MulticastPacketsSent++; 3750 else 3751 m->UnicastPacketsSent++; 3752 #endif // APPLE_OSX_mDNSResponder 3753 3754 // Zero-length message data is okay (e.g. for a DNS Update ack, where all we need is an ID and an error code 3755 if (end < msg->data || end - msg->data > AbsoluteMaxDNSMessageData) 3756 { 3757 LogMsg("mDNSSendDNSMessage: invalid message %p %p %d", msg->data, end, end - msg->data); 3758 return mStatus_BadParamErr; 3759 } 3760 3761 newend = putHINFO(m, msg, end, authInfo, limit); 3762 if (!newend) LogMsg("mDNSSendDNSMessage: putHINFO failed msg %p end %p, limit %p", msg->data, end, limit); // Not fatal 3763 else end = newend; 3764 3765 // Put all the integer values in IETF byte-order (MSB first, LSB second) 3766 SwapDNSHeaderBytes(msg); 3767 3768 if (authInfo) DNSDigest_SignMessage(msg, &end, authInfo, 0); // DNSDigest_SignMessage operates on message in network byte order 3769 if (!end) { LogMsg("mDNSSendDNSMessage: DNSDigest_SignMessage failed"); status = mStatus_NoMemoryErr; } 3770 else 3771 { 3772 // Send the packet on the wire 3773 if (!sock) 3774 status = mDNSPlatformSendUDP(m, msg, end, InterfaceID, src, dst, dstport, useBackgroundTrafficClass); 3775 else 3776 { 3777 mDNSu16 msglen = (mDNSu16)(end - (mDNSu8 *)msg); 3778 mDNSu8 lenbuf[2] = { (mDNSu8)(msglen >> 8), (mDNSu8)(msglen & 0xFF) }; 3779 char *buf; 3780 long nsent; 3781 3782 // Try to send them in one packet if we can allocate enough memory 3783 buf = mDNSPlatformMemAllocate(msglen + 2); 3784 if (buf) 3785 { 3786 buf[0] = lenbuf[0]; 3787 buf[1] = lenbuf[1]; 3788 mDNSPlatformMemCopy(buf+2, msg, msglen); 3789 nsent = mDNSPlatformWriteTCP(sock, buf, msglen+2); 3790 if (nsent != (msglen + 2)) 3791 { 3792 LogMsg("mDNSSendDNSMessage: write message failed %d/%d", nsent, msglen); 3793 status = mStatus_ConnFailed; 3794 } 3795 mDNSPlatformMemFree(buf); 3796 } 3797 else 3798 { 3799 nsent = mDNSPlatformWriteTCP(sock, (char*)lenbuf, 2); 3800 if (nsent != 2) 3801 { 3802 LogMsg("mDNSSendDNSMessage: write msg length failed %d/%d", nsent, 2); 3803 status = mStatus_ConnFailed; 3804 } 3805 else 3806 { 3807 nsent = mDNSPlatformWriteTCP(sock, (char *)msg, msglen); 3808 if (nsent != msglen) 3809 { 3810 LogMsg("mDNSSendDNSMessage: write msg body failed %d/%d", nsent, msglen); 3811 status = mStatus_ConnFailed; 3812 } 3813 } 3814 } 3815 } 3816 } 3817 3818 // Swap the integer values back the way they were (remember that numAdditionals may have been changed by putHINFO and/or SignMessage) 3819 SwapDNSHeaderBytes(msg); 3820 3821 // Dump the packet with the HINFO and TSIG 3822 if (mDNS_PacketLoggingEnabled && !mDNSOpaque16IsZero(msg->h.id)) { 3823 mDNSIPPort port = MulticastDNSPort; 3824 DumpPacket(m, status, mDNStrue, sock && 3825 (sock->flags & kTCPSocketFlags_UseTLS) ? 3826 "TLS" : sock ? "TCP" : "UDP", mDNSNULL, 3827 src ? src->port : port, dst, dstport, msg, end); 3828 } 3829 3830 // put the number of additionals back the way it was 3831 msg->h.numAdditionals = numAdditionals; 3832 3833 return(status); 3834 } 3835 3836 // *************************************************************************** 3837 #if COMPILER_LIKES_PRAGMA_MARK 3838 #pragma mark - 3839 #pragma mark - RR List Management & Task Management 3840 #endif 3841 3842 mDNSexport void mDNS_Lock_(mDNS *const m, const char * const functionname) 3843 { 3844 // MUST grab the platform lock FIRST! 3845 mDNSPlatformLock(m); 3846 3847 // Normally, mDNS_reentrancy is zero and so is mDNS_busy 3848 // However, when we call a client callback mDNS_busy is one, and we increment mDNS_reentrancy too 3849 // If that client callback does mDNS API calls, mDNS_reentrancy and mDNS_busy will both be one 3850 // If mDNS_busy != mDNS_reentrancy that's a bad sign 3851 if (m->mDNS_busy != m->mDNS_reentrancy) 3852 { 3853 LogMsg("%s: mDNS_Lock: Locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", functionname, m->mDNS_busy, m->mDNS_reentrancy); 3854 #if ForceAlerts 3855 *(long*)0 = 0; 3856 #endif 3857 } 3858 3859 // If this is an initial entry into the mDNSCore code, set m->timenow 3860 // else, if this is a re-entrant entry into the mDNSCore code, m->timenow should already be set 3861 if (m->mDNS_busy == 0) 3862 { 3863 if (m->timenow) 3864 LogMsg("%s: mDNS_Lock: m->timenow already set (%ld/%ld)", functionname, m->timenow, mDNS_TimeNow_NoLock(m)); 3865 m->timenow = mDNS_TimeNow_NoLock(m); 3866 if (m->timenow == 0) m->timenow = 1; 3867 } 3868 else if (m->timenow == 0) 3869 { 3870 LogMsg("%s: mDNS_Lock: m->mDNS_busy is %ld but m->timenow not set", functionname, m->mDNS_busy); 3871 m->timenow = mDNS_TimeNow_NoLock(m); 3872 if (m->timenow == 0) m->timenow = 1; 3873 } 3874 3875 if (m->timenow_last - m->timenow > 0) 3876 { 3877 m->timenow_adjust += m->timenow_last - m->timenow; 3878 LogMsg("%s: mDNSPlatformRawTime went backwards by %ld ticks; setting correction factor to %ld", functionname, m->timenow_last - m->timenow, m->timenow_adjust); 3879 m->timenow = m->timenow_last; 3880 } 3881 m->timenow_last = m->timenow; 3882 3883 // Increment mDNS_busy so we'll recognise re-entrant calls 3884 m->mDNS_busy++; 3885 } 3886 3887 mDNSlocal AuthRecord *AnyLocalRecordReady(const mDNS *const m) 3888 { 3889 AuthRecord *rr; 3890 for (rr = m->NewLocalRecords; rr; rr = rr->next) 3891 if (LocalRecordReady(rr)) return rr; 3892 return mDNSNULL; 3893 } 3894 3895 mDNSlocal mDNSs32 GetNextScheduledEvent(const mDNS *const m) 3896 { 3897 mDNSs32 e = m->timenow + 0x78000000; 3898 if (m->mDNSPlatformStatus != mStatus_NoError) return(e); 3899 if (m->NewQuestions) 3900 { 3901 if (m->NewQuestions->DelayAnswering) e = m->NewQuestions->DelayAnswering; 3902 else return(m->timenow); 3903 } 3904 if (m->NewLocalOnlyQuestions) return(m->timenow); 3905 if (m->NewLocalRecords && AnyLocalRecordReady(m)) return(m->timenow); 3906 if (m->NewLocalOnlyRecords) return(m->timenow); 3907 if (m->SPSProxyListChanged) return(m->timenow); 3908 if (m->LocalRemoveEvents) return(m->timenow); 3909 3910 #ifndef UNICAST_DISABLED 3911 if (e - m->NextuDNSEvent > 0) e = m->NextuDNSEvent; 3912 if (e - m->NextScheduledNATOp > 0) e = m->NextScheduledNATOp; 3913 if (m->NextSRVUpdate && e - m->NextSRVUpdate > 0) e = m->NextSRVUpdate; 3914 #endif 3915 3916 if (e - m->NextCacheCheck > 0) e = m->NextCacheCheck; 3917 if (e - m->NextScheduledSPS > 0) e = m->NextScheduledSPS; 3918 if (e - m->NextScheduledKA > 0) e = m->NextScheduledKA; 3919 3920 // NextScheduledSPRetry only valid when DelaySleep not set 3921 if (!m->DelaySleep && m->SleepLimit && e - m->NextScheduledSPRetry > 0) e = m->NextScheduledSPRetry; 3922 if (m->DelaySleep && e - m->DelaySleep > 0) e = m->DelaySleep; 3923 3924 if (m->SuppressSending) 3925 { 3926 if (e - m->SuppressSending > 0) e = m->SuppressSending; 3927 } 3928 else 3929 { 3930 if (e - m->NextScheduledQuery > 0) e = m->NextScheduledQuery; 3931 if (e - m->NextScheduledProbe > 0) e = m->NextScheduledProbe; 3932 if (e - m->NextScheduledResponse > 0) e = m->NextScheduledResponse; 3933 } 3934 if (e - m->NextScheduledStopTime > 0) e = m->NextScheduledStopTime; 3935 return(e); 3936 } 3937 3938 mDNSexport void ShowTaskSchedulingError(mDNS *const m) 3939 { 3940 AuthRecord *rr; 3941 mDNS_Lock(m); 3942 3943 LogMsg("Task Scheduling Error: Continuously busy for more than a second"); 3944 3945 // Note: To accurately diagnose *why* we're busy, the debugging code here needs to mirror the logic in GetNextScheduledEvent above 3946 3947 if (m->NewQuestions && (!m->NewQuestions->DelayAnswering || m->timenow - m->NewQuestions->DelayAnswering >= 0)) 3948 LogMsg("Task Scheduling Error: NewQuestion %##s (%s)", 3949 m->NewQuestions->qname.c, DNSTypeName(m->NewQuestions->qtype)); 3950 3951 if (m->NewLocalOnlyQuestions) 3952 LogMsg("Task Scheduling Error: NewLocalOnlyQuestions %##s (%s)", 3953 m->NewLocalOnlyQuestions->qname.c, DNSTypeName(m->NewLocalOnlyQuestions->qtype)); 3954 3955 if (m->NewLocalRecords) 3956 { 3957 rr = AnyLocalRecordReady(m); 3958 if (rr) LogMsg("Task Scheduling Error: NewLocalRecords %s", ARDisplayString(m, rr)); 3959 } 3960 3961 if (m->NewLocalOnlyRecords) LogMsg("Task Scheduling Error: NewLocalOnlyRecords"); 3962 3963 if (m->SPSProxyListChanged) LogMsg("Task Scheduling Error: SPSProxyListChanged"); 3964 if (m->LocalRemoveEvents) LogMsg("Task Scheduling Error: LocalRemoveEvents"); 3965 3966 if (m->timenow - m->NextScheduledEvent >= 0) 3967 LogMsg("Task Scheduling Error: m->NextScheduledEvent %d", m->timenow - m->NextScheduledEvent); 3968 3969 #ifndef UNICAST_DISABLED 3970 if (m->timenow - m->NextuDNSEvent >= 0) 3971 LogMsg("Task Scheduling Error: m->NextuDNSEvent %d", m->timenow - m->NextuDNSEvent); 3972 if (m->timenow - m->NextScheduledNATOp >= 0) 3973 LogMsg("Task Scheduling Error: m->NextScheduledNATOp %d", m->timenow - m->NextScheduledNATOp); 3974 if (m->NextSRVUpdate && m->timenow - m->NextSRVUpdate >= 0) 3975 LogMsg("Task Scheduling Error: m->NextSRVUpdate %d", m->timenow - m->NextSRVUpdate); 3976 #endif 3977 3978 if (m->timenow - m->NextCacheCheck >= 0) 3979 LogMsg("Task Scheduling Error: m->NextCacheCheck %d", m->timenow - m->NextCacheCheck); 3980 if (m->timenow - m->NextScheduledSPS >= 0) 3981 LogMsg("Task Scheduling Error: m->NextScheduledSPS %d", m->timenow - m->NextScheduledSPS); 3982 if (m->timenow - m->NextScheduledKA >= 0) 3983 LogMsg("Task Scheduling Error: m->NextScheduledKA %d", m->timenow - m->NextScheduledKA); 3984 if (!m->DelaySleep && m->SleepLimit && m->timenow - m->NextScheduledSPRetry >= 0) 3985 LogMsg("Task Scheduling Error: m->NextScheduledSPRetry %d", m->timenow - m->NextScheduledSPRetry); 3986 if (m->DelaySleep && m->timenow - m->DelaySleep >= 0) 3987 LogMsg("Task Scheduling Error: m->DelaySleep %d", m->timenow - m->DelaySleep); 3988 3989 if (m->SuppressSending && m->timenow - m->SuppressSending >= 0) 3990 LogMsg("Task Scheduling Error: m->SuppressSending %d", m->timenow - m->SuppressSending); 3991 if (m->timenow - m->NextScheduledQuery >= 0) 3992 LogMsg("Task Scheduling Error: m->NextScheduledQuery %d", m->timenow - m->NextScheduledQuery); 3993 if (m->timenow - m->NextScheduledProbe >= 0) 3994 LogMsg("Task Scheduling Error: m->NextScheduledProbe %d", m->timenow - m->NextScheduledProbe); 3995 if (m->timenow - m->NextScheduledResponse >= 0) 3996 LogMsg("Task Scheduling Error: m->NextScheduledResponse %d", m->timenow - m->NextScheduledResponse); 3997 3998 mDNS_Unlock(m); 3999 } 4000 4001 mDNSexport void mDNS_Unlock_(mDNS *const m, const char * const functionname) 4002 { 4003 // Decrement mDNS_busy 4004 m->mDNS_busy--; 4005 4006 // Check for locking failures 4007 if (m->mDNS_busy != m->mDNS_reentrancy) 4008 { 4009 LogMsg("%s: mDNS_Unlock: Locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", functionname, m->mDNS_busy, m->mDNS_reentrancy); 4010 #if ForceAlerts 4011 *(long*)0 = 0; 4012 #endif 4013 } 4014 4015 // If this is a final exit from the mDNSCore code, set m->NextScheduledEvent and clear m->timenow 4016 if (m->mDNS_busy == 0) 4017 { 4018 m->NextScheduledEvent = GetNextScheduledEvent(m); 4019 if (m->timenow == 0) LogMsg("%s: mDNS_Unlock: ERROR! m->timenow aready zero", functionname); 4020 m->timenow = 0; 4021 } 4022 4023 // MUST release the platform lock LAST! 4024 mDNSPlatformUnlock(m); 4025 } 4026 4027 // *************************************************************************** 4028 #if COMPILER_LIKES_PRAGMA_MARK 4029 #pragma mark - 4030 #pragma mark - Specialized mDNS version of vsnprintf 4031 #endif 4032 4033 static const struct mDNSprintf_format 4034 { 4035 unsigned leftJustify : 1; 4036 unsigned forceSign : 1; 4037 unsigned zeroPad : 1; 4038 unsigned havePrecision : 1; 4039 unsigned hSize : 1; 4040 unsigned lSize : 1; 4041 char altForm; 4042 char sign; // +, - or space 4043 unsigned int fieldWidth; 4044 unsigned int precision; 4045 } mDNSprintf_format_default = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; 4046 4047 mDNSexport mDNSu32 mDNS_vsnprintf(char *sbuffer, mDNSu32 buflen, const char *fmt, va_list arg) 4048 { 4049 mDNSu32 nwritten = 0; 4050 int c; 4051 if (buflen == 0) return(0); 4052 buflen--; // Pre-reserve one space in the buffer for the terminating null 4053 if (buflen == 0) goto exit; 4054 4055 for (c = *fmt; c != 0; c = *++fmt) 4056 { 4057 if (c != '%') 4058 { 4059 *sbuffer++ = (char)c; 4060 if (++nwritten >= buflen) goto exit; 4061 } 4062 else 4063 { 4064 unsigned int i=0, j; 4065 // The mDNS Vsprintf Argument Conversion Buffer is used as a temporary holding area for 4066 // generating decimal numbers, hexdecimal numbers, IP addresses, domain name strings, etc. 4067 // The size needs to be enough for a 256-byte domain name plus some error text. 4068 #define mDNS_VACB_Size 300 4069 char mDNS_VACB[mDNS_VACB_Size]; 4070 #define mDNS_VACB_Lim (&mDNS_VACB[mDNS_VACB_Size]) 4071 #define mDNS_VACB_Remain(s) ((mDNSu32)(mDNS_VACB_Lim - s)) 4072 char *s = mDNS_VACB_Lim, *digits; 4073 struct mDNSprintf_format F = mDNSprintf_format_default; 4074 4075 while (1) // decode flags 4076 { 4077 c = *++fmt; 4078 if (c == '-') F.leftJustify = 1; 4079 else if (c == '+') F.forceSign = 1; 4080 else if (c == ' ') F.sign = ' '; 4081 else if (c == '#') F.altForm++; 4082 else if (c == '0') F.zeroPad = 1; 4083 else break; 4084 } 4085 4086 if (c == '*') // decode field width 4087 { 4088 int f = va_arg(arg, int); 4089 if (f < 0) { f = -f; F.leftJustify = 1; } 4090 F.fieldWidth = (unsigned int)f; 4091 c = *++fmt; 4092 } 4093 else 4094 { 4095 for (; c >= '0' && c <= '9'; c = *++fmt) 4096 F.fieldWidth = (10 * F.fieldWidth) + (c - '0'); 4097 } 4098 4099 if (c == '.') // decode precision 4100 { 4101 if ((c = *++fmt) == '*') 4102 { F.precision = va_arg(arg, unsigned int); c = *++fmt; } 4103 else for (; c >= '0' && c <= '9'; c = *++fmt) 4104 F.precision = (10 * F.precision) + (c - '0'); 4105 F.havePrecision = 1; 4106 } 4107 4108 if (F.leftJustify) F.zeroPad = 0; 4109 4110 conv: 4111 switch (c) // perform appropriate conversion 4112 { 4113 unsigned long n; 4114 case 'h': F.hSize = 1; c = *++fmt; goto conv; 4115 case 'l': // fall through 4116 case 'L': F.lSize = 1; c = *++fmt; goto conv; 4117 case 'd': 4118 case 'i': if (F.lSize) n = (unsigned long)va_arg(arg, long); 4119 else n = (unsigned long)va_arg(arg, int); 4120 if (F.hSize) n = (short) n; 4121 if ((long) n < 0) { n = (unsigned long)-(long)n; F.sign = '-'; } 4122 else if (F.forceSign) F.sign = '+'; 4123 goto decimal; 4124 case 'u': if (F.lSize) n = va_arg(arg, unsigned long); 4125 else n = va_arg(arg, unsigned int); 4126 if (F.hSize) n = (unsigned short) n; 4127 F.sign = 0; 4128 goto decimal; 4129 decimal: if (!F.havePrecision) 4130 { 4131 if (F.zeroPad) 4132 { 4133 F.precision = F.fieldWidth; 4134 if (F.sign) --F.precision; 4135 } 4136 if (F.precision < 1) F.precision = 1; 4137 } 4138 if (F.precision > mDNS_VACB_Size - 1) 4139 F.precision = mDNS_VACB_Size - 1; 4140 for (i = 0; n; n /= 10, i++) *--s = (char)(n % 10 + '0'); 4141 for (; i < F.precision; i++) *--s = '0'; 4142 if (F.sign) { *--s = F.sign; i++; } 4143 break; 4144 4145 case 'o': if (F.lSize) n = va_arg(arg, unsigned long); 4146 else n = va_arg(arg, unsigned int); 4147 if (F.hSize) n = (unsigned short) n; 4148 if (!F.havePrecision) 4149 { 4150 if (F.zeroPad) F.precision = F.fieldWidth; 4151 if (F.precision < 1) F.precision = 1; 4152 } 4153 if (F.precision > mDNS_VACB_Size - 1) 4154 F.precision = mDNS_VACB_Size - 1; 4155 for (i = 0; n; n /= 8, i++) *--s = (char)(n % 8 + '0'); 4156 if (F.altForm && i && *s != '0') { *--s = '0'; i++; } 4157 for (; i < F.precision; i++) *--s = '0'; 4158 break; 4159 4160 case 'a': { 4161 unsigned char *a = va_arg(arg, unsigned char *); 4162 if (!a) { static char emsg[] = "<<NULL>>"; s = emsg; i = sizeof(emsg)-1; } 4163 else 4164 { 4165 s = mDNS_VACB; // Adjust s to point to the start of the buffer, not the end 4166 if (F.altForm) 4167 { 4168 mDNSAddr *ip = (mDNSAddr*)a; 4169 switch (ip->type) 4170 { 4171 case mDNSAddrType_IPv4: F.precision = 4; a = (unsigned char *)&ip->ip.v4; break; 4172 case mDNSAddrType_IPv6: F.precision = 16; a = (unsigned char *)&ip->ip.v6; break; 4173 default: F.precision = 0; break; 4174 } 4175 } 4176 if (F.altForm && !F.precision) 4177 i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "«ZERO ADDRESS»"); 4178 else switch (F.precision) 4179 { 4180 case 4: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%d.%d.%d.%d", 4181 a[0], a[1], a[2], a[3]); break; 4182 case 6: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%02X:%02X:%02X:%02X:%02X:%02X", 4183 a[0], a[1], a[2], a[3], a[4], a[5]); break; 4184 case 16: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), 4185 "%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X", 4186 a[0x0], a[0x1], a[0x2], a[0x3], a[0x4], a[0x5], a[0x6], a[0x7], 4187 a[0x8], a[0x9], a[0xA], a[0xB], a[0xC], a[0xD], a[0xE], a[0xF]); break; 4188 default: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%s", "<< ERROR: Must specify" 4189 " address size (i.e. %.4a=IPv4, %.6a=Ethernet, %.16a=IPv6) >>"); break; 4190 } 4191 } 4192 } 4193 break; 4194 4195 case 'p': F.havePrecision = F.lSize = 1; 4196 F.precision = sizeof(void*) * 2; // 8 characters on 32-bit; 16 characters on 64-bit 4197 case 'X': digits = "0123456789ABCDEF"; 4198 goto hexadecimal; 4199 case 'x': digits = "0123456789abcdef"; 4200 hexadecimal: if (F.lSize) n = va_arg(arg, unsigned long); 4201 else n = va_arg(arg, unsigned int); 4202 if (F.hSize) n = (unsigned short) n; 4203 if (!F.havePrecision) 4204 { 4205 if (F.zeroPad) 4206 { 4207 F.precision = F.fieldWidth; 4208 if (F.altForm) F.precision -= 2; 4209 } 4210 if (F.precision < 1) F.precision = 1; 4211 } 4212 if (F.precision > mDNS_VACB_Size - 1) 4213 F.precision = mDNS_VACB_Size - 1; 4214 for (i = 0; n; n /= 16, i++) *--s = digits[n % 16]; 4215 for (; i < F.precision; i++) *--s = '0'; 4216 if (F.altForm) { *--s = (char)c; *--s = '0'; i += 2; } 4217 break; 4218 4219 case 'c': *--s = (char)va_arg(arg, int); i = 1; break; 4220 4221 case 's': s = va_arg(arg, char *); 4222 if (!s) { static char emsg[] = "<<NULL>>"; s = emsg; i = sizeof(emsg)-1; } 4223 else switch (F.altForm) 4224 { 4225 case 0: i=0; 4226 if (!F.havePrecision) // C string 4227 while (s[i]) i++; 4228 else 4229 { 4230 while ((i < F.precision) && s[i]) i++; 4231 // Make sure we don't truncate in the middle of a UTF-8 character 4232 // If last character we got was any kind of UTF-8 multi-byte character, 4233 // then see if we have to back up. 4234 // This is not as easy as the similar checks below, because 4235 // here we can't assume it's safe to examine the *next* byte, so we 4236 // have to confine ourselves to working only backwards in the string. 4237 j = i; // Record where we got to 4238 // Now, back up until we find first non-continuation-char 4239 while (i>0 && (s[i-1] & 0xC0) == 0x80) i--; 4240 // Now s[i-1] is the first non-continuation-char 4241 // and (j-i) is the number of continuation-chars we found 4242 if (i>0 && (s[i-1] & 0xC0) == 0xC0) // If we found a start-char 4243 { 4244 i--; // Tentatively eliminate this start-char as well 4245 // Now (j-i) is the number of characters we're considering eliminating. 4246 // To be legal UTF-8, the start-char must contain (j-i) one-bits, 4247 // followed by a zero bit. If we shift it right by (7-(j-i)) bits 4248 // (with sign extension) then the result has to be 0xFE. 4249 // If this is right, then we reinstate the tentatively eliminated bytes. 4250 if (((j-i) < 7) && (((s[i] >> (7-(j-i))) & 0xFF) == 0xFE)) i = j; 4251 } 4252 } 4253 break; 4254 case 1: i = (unsigned char) *s++; break; // Pascal string 4255 case 2: { // DNS label-sequence name 4256 unsigned char *a = (unsigned char *)s; 4257 s = mDNS_VACB; // Adjust s to point to the start of the buffer, not the end 4258 if (*a == 0) *s++ = '.'; // Special case for root DNS name 4259 while (*a) 4260 { 4261 char buf[63*4+1]; 4262 if (*a > 63) 4263 { s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "<<INVALID LABEL LENGTH %u>>", *a); break; } 4264 if (s + *a >= &mDNS_VACB[254]) 4265 { s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "<<NAME TOO LONG>>"); break; } 4266 // Need to use ConvertDomainLabelToCString to do proper escaping here, 4267 // so it's clear what's a literal dot and what's a label separator 4268 ConvertDomainLabelToCString((domainlabel*)a, buf); 4269 s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "%s.", buf); 4270 a += 1 + *a; 4271 } 4272 i = (mDNSu32)(s - mDNS_VACB); 4273 s = mDNS_VACB; // Reset s back to the start of the buffer 4274 break; 4275 } 4276 } 4277 // Make sure we don't truncate in the middle of a UTF-8 character (see similar comment below) 4278 if (F.havePrecision && i > F.precision) 4279 { i = F.precision; while (i>0 && (s[i] & 0xC0) == 0x80) i--;} 4280 break; 4281 4282 case 'n': s = va_arg(arg, char *); 4283 if (F.hSize) *(short *) s = (short)nwritten; 4284 else if (F.lSize) *(long *) s = (long)nwritten; 4285 else *(int *) s = (int)nwritten; 4286 continue; 4287 4288 default: s = mDNS_VACB; 4289 i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "<<UNKNOWN FORMAT CONVERSION CODE %%%c>>", c); 4290 4291 case '%': *sbuffer++ = (char)c; 4292 if (++nwritten >= buflen) goto exit; 4293 break; 4294 } 4295 4296 if (i < F.fieldWidth && !F.leftJustify) // Pad on the left 4297 do { 4298 *sbuffer++ = ' '; 4299 if (++nwritten >= buflen) goto exit; 4300 } while (i < --F.fieldWidth); 4301 4302 // Make sure we don't truncate in the middle of a UTF-8 character. 4303 // Note: s[i] is the first eliminated character; i.e. the next character *after* the last character of the 4304 // allowed output. If s[i] is a UTF-8 continuation character, then we've cut a unicode character in half, 4305 // so back up 'i' until s[i] is no longer a UTF-8 continuation character. (if the input was proprly 4306 // formed, s[i] will now be the UTF-8 start character of the multi-byte character we just eliminated). 4307 if (i > buflen - nwritten) 4308 { i = buflen - nwritten; while (i>0 && (s[i] & 0xC0) == 0x80) i--;} 4309 for (j=0; j<i; j++) *sbuffer++ = *s++; // Write the converted result 4310 nwritten += i; 4311 if (nwritten >= buflen) goto exit; 4312 4313 for (; i < F.fieldWidth; i++) // Pad on the right 4314 { 4315 *sbuffer++ = ' '; 4316 if (++nwritten >= buflen) goto exit; 4317 } 4318 } 4319 } 4320 exit: 4321 *sbuffer++ = 0; 4322 return(nwritten); 4323 } 4324 4325 mDNSexport mDNSu32 mDNS_snprintf(char *sbuffer, mDNSu32 buflen, const char *fmt, ...) 4326 { 4327 mDNSu32 length; 4328 4329 va_list ptr; 4330 va_start(ptr,fmt); 4331 length = mDNS_vsnprintf(sbuffer, buflen, fmt, ptr); 4332 va_end(ptr); 4333 4334 return(length); 4335 } 4336