1 /* -*- Mode: C; tab-width: 4 -*- 2 * 3 * Copyright (c) 2002-2015 Apple 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 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 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->euid = 0; 1485 q->DisallowPID = mDNSfalse; 1486 q->ServiceID = -1; 1487 q->QuestionCallback = callback; 1488 q->QuestionContext = context; 1489 } 1490 1491 mDNSexport mDNSu32 RDataHashValue(const ResourceRecord *const rr) 1492 { 1493 int len = rr->rdlength; 1494 const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; 1495 const mDNSu8 *ptr = rdb->data; 1496 mDNSu32 sum = 0; 1497 1498 switch(rr->rrtype) 1499 { 1500 case kDNSType_NS: 1501 case kDNSType_MD: 1502 case kDNSType_MF: 1503 case kDNSType_CNAME: 1504 case kDNSType_MB: 1505 case kDNSType_MG: 1506 case kDNSType_MR: 1507 case kDNSType_PTR: 1508 case kDNSType_NSAP_PTR: 1509 case kDNSType_DNAME: return DomainNameHashValue(&rdb->name); 1510 1511 case kDNSType_SOA: return rdb->soa.serial + 1512 rdb->soa.refresh + 1513 rdb->soa.retry + 1514 rdb->soa.expire + 1515 rdb->soa.min + 1516 DomainNameHashValue(&rdb->soa.mname) + 1517 DomainNameHashValue(&rdb->soa.rname); 1518 1519 case kDNSType_MX: 1520 case kDNSType_AFSDB: 1521 case kDNSType_RT: 1522 case kDNSType_KX: return DomainNameHashValue(&rdb->mx.exchange); 1523 1524 case kDNSType_MINFO: 1525 case kDNSType_RP: return DomainNameHashValue(&rdb->rp.mbox) + DomainNameHashValue(&rdb->rp.txt); 1526 1527 case kDNSType_PX: return DomainNameHashValue(&rdb->px.map822) + DomainNameHashValue(&rdb->px.mapx400); 1528 1529 case kDNSType_SRV: return DomainNameHashValue(&rdb->srv.target); 1530 1531 case kDNSType_OPT: return 0; // OPT is a pseudo-RR container structure; makes no sense to compare 1532 1533 case kDNSType_NSEC: { 1534 int dlen; 1535 dlen = DomainNameLength((domainname *)rdb->data); 1536 sum = DomainNameHashValue((domainname *)rdb->data); 1537 ptr += dlen; 1538 len -= dlen; 1539 /* FALLTHROUGH */ 1540 } 1541 1542 default: 1543 { 1544 int i; 1545 for (i=0; i+1 < len; i+=2) 1546 { 1547 sum += (((mDNSu32)(ptr[i])) << 8) | ptr[i+1]; 1548 sum = (sum<<3) | (sum>>29); 1549 } 1550 if (i < len) 1551 { 1552 sum += ((mDNSu32)(ptr[i])) << 8; 1553 } 1554 return(sum); 1555 } 1556 } 1557 } 1558 1559 // r1 has to be a full ResourceRecord including rrtype and rdlength 1560 // r2 is just a bare RDataBody, which MUST be the same rrtype and rdlength as r1 1561 mDNSexport mDNSBool SameRDataBody(const ResourceRecord *const r1, const RDataBody *const r2, DomainNameComparisonFn *samename) 1562 { 1563 const RDataBody2 *const b1 = (RDataBody2 *)r1->rdata->u.data; 1564 const RDataBody2 *const b2 = (RDataBody2 *)r2; 1565 switch(r1->rrtype) 1566 { 1567 case kDNSType_NS: 1568 case kDNSType_MD: 1569 case kDNSType_MF: 1570 case kDNSType_CNAME: 1571 case kDNSType_MB: 1572 case kDNSType_MG: 1573 case kDNSType_MR: 1574 case kDNSType_PTR: 1575 case kDNSType_NSAP_PTR: 1576 case kDNSType_DNAME: return(SameDomainName(&b1->name, &b2->name)); 1577 1578 case kDNSType_SOA: return (mDNSBool)( b1->soa.serial == b2->soa.serial && 1579 b1->soa.refresh == b2->soa.refresh && 1580 b1->soa.retry == b2->soa.retry && 1581 b1->soa.expire == b2->soa.expire && 1582 b1->soa.min == b2->soa.min && 1583 samename(&b1->soa.mname, &b2->soa.mname) && 1584 samename(&b1->soa.rname, &b2->soa.rname)); 1585 1586 case kDNSType_MX: 1587 case kDNSType_AFSDB: 1588 case kDNSType_RT: 1589 case kDNSType_KX: return (mDNSBool)( b1->mx.preference == b2->mx.preference && 1590 samename(&b1->mx.exchange, &b2->mx.exchange)); 1591 1592 case kDNSType_MINFO: 1593 case kDNSType_RP: return (mDNSBool)( samename(&b1->rp.mbox, &b2->rp.mbox) && 1594 samename(&b1->rp.txt, &b2->rp.txt)); 1595 1596 case kDNSType_PX: return (mDNSBool)( b1->px.preference == b2->px.preference && 1597 samename(&b1->px.map822, &b2->px.map822) && 1598 samename(&b1->px.mapx400, &b2->px.mapx400)); 1599 1600 case kDNSType_SRV: return (mDNSBool)( b1->srv.priority == b2->srv.priority && 1601 b1->srv.weight == b2->srv.weight && 1602 mDNSSameIPPort(b1->srv.port, b2->srv.port) && 1603 samename(&b1->srv.target, &b2->srv.target)); 1604 1605 case kDNSType_OPT: return mDNSfalse; // OPT is a pseudo-RR container structure; makes no sense to compare 1606 case kDNSType_NSEC: { 1607 // If the "nxt" name changes in case, we want to delete the old 1608 // and store just the new one. If the caller passes in SameDomainCS for "samename", 1609 // we would return "false" when the only change between the two rdata is the case 1610 // change in "nxt". 1611 // 1612 // Note: rdlength of both the RData are same (ensured by the caller) and hence we can 1613 // use just r1->rdlength below 1614 1615 int dlen1 = DomainNameLength((domainname *)b1->data); 1616 int dlen2 = DomainNameLength((domainname *)b2->data); 1617 return (mDNSBool)(dlen1 == dlen2 && 1618 samename((domainname *)b1->data, (domainname *)b2->data) && 1619 mDNSPlatformMemSame(b1->data + dlen1, b2->data + dlen2, r1->rdlength - dlen1)); 1620 } 1621 1622 default: return(mDNSPlatformMemSame(b1->data, b2->data, r1->rdlength)); 1623 } 1624 } 1625 1626 mDNSexport mDNSBool BitmapTypeCheck(mDNSu8 *bmap, int bitmaplen, mDNSu16 type) 1627 { 1628 int win, wlen; 1629 int wintype; 1630 1631 // The window that this type belongs to. NSEC has 256 windows that 1632 // comprises of 256 types. 1633 wintype = type >> 8; 1634 1635 while (bitmaplen > 0) 1636 { 1637 if (bitmaplen < 3) 1638 { 1639 LogInfo("BitmapTypeCheck: malformed nsec, bitmaplen %d short", bitmaplen); 1640 return mDNSfalse; 1641 } 1642 1643 win = *bmap++; 1644 wlen = *bmap++; 1645 bitmaplen -= 2; 1646 if (bitmaplen < wlen || wlen < 1 || wlen > 32) 1647 { 1648 LogInfo("BitmapTypeCheck: malformed nsec, bitmaplen %d wlen %d, win %d", bitmaplen, wlen, win); 1649 return mDNSfalse; 1650 } 1651 if (win < 0 || win >= 256) 1652 { 1653 LogInfo("BitmapTypeCheck: malformed nsec, wlen %d", wlen); 1654 return mDNSfalse; 1655 } 1656 if (win == wintype) 1657 { 1658 // First byte in the window serves 0 to 7, the next one serves 8 to 15 and so on. 1659 // Calculate the right byte offset first. 1660 int boff = (type & 0xff ) >> 3; 1661 if (wlen <= boff) 1662 return mDNSfalse; 1663 // The last three bits values 0 to 7 corresponds to bit positions 1664 // within the byte. 1665 return (bmap[boff] & (0x80 >> (type & 7))); 1666 } 1667 else 1668 { 1669 // If the windows are ordered, then we could check to see 1670 // if wintype > win and then return early. 1671 bmap += wlen; 1672 bitmaplen -= wlen; 1673 } 1674 } 1675 return mDNSfalse; 1676 } 1677 1678 // Don't call this function if the resource record is not NSEC. It will return false 1679 // which means that the type does not exist. 1680 mDNSexport mDNSBool RRAssertsExistence(const ResourceRecord *const rr, mDNSu16 type) 1681 { 1682 const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; 1683 mDNSu8 *nsec = (mDNSu8 *)rdb->data; 1684 int len, bitmaplen; 1685 mDNSu8 *bmap; 1686 1687 if (rr->rrtype != kDNSType_NSEC) return mDNSfalse; 1688 1689 len = DomainNameLength((domainname *)nsec); 1690 1691 bitmaplen = rr->rdlength - len; 1692 bmap = nsec + len; 1693 return (BitmapTypeCheck(bmap, bitmaplen, type)); 1694 } 1695 1696 // Don't call this function if the resource record is not NSEC. It will return false 1697 // which means that the type exists. 1698 mDNSexport mDNSBool RRAssertsNonexistence(const ResourceRecord *const rr, mDNSu16 type) 1699 { 1700 if (rr->rrtype != kDNSType_NSEC) return mDNSfalse; 1701 1702 return !RRAssertsExistence(rr, type); 1703 } 1704 1705 // Checks whether the RRSIG or NSEC record answers the question "q". 1706 mDNSlocal mDNSBool DNSSECRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q, mDNSBool *checkType) 1707 { 1708 *checkType = mDNStrue; 1709 1710 // This function is called for all questions and as long as the type matches, 1711 // return true. For the types (RRSIG and NSEC) that are specifically checked in 1712 // this function, returning true still holds good. 1713 if (q->qtype == rr->rrtype) 1714 return mDNStrue; 1715 1716 // For DS and DNSKEY questions, the types should match i.e., don't answer using CNAME 1717 // records as it answers any question type. 1718 // 1719 // - DS record comes from the parent zone where CNAME record cannot coexist and hence 1720 // cannot possibly answer it. 1721 // 1722 // - For DNSKEY, one could potentially follow CNAME but there could be a DNSKEY at 1723 // the "qname" itself. To keep it simple, we don't follow CNAME. 1724 1725 if ((q->qtype == kDNSType_DS || q->qtype == kDNSType_DNSKEY) && (q->qtype != rr->rrtype)) 1726 { 1727 debugf("DNSSECRecordAnswersQuestion: %d type resource record matched question %##s (%s), ignoring", rr->rrtype, 1728 q->qname.c, DNSTypeName(q->qtype)); 1729 return mDNSfalse; 1730 } 1731 1732 // If we are validating a response using DNSSEC, we might already have the records 1733 // for the "q->qtype" in the cache but we issued a query with DO bit set 1734 // to get the RRSIGs e.g., if you have two questions one of which does not require 1735 // DNSSEC validation. When the RRSIG is added to the cache, we need to deliver 1736 // the response to the question. The RRSIG type won't match the q->qtype and hence 1737 // we need to bypass the check in that case. 1738 if (rr->rrtype == kDNSType_RRSIG && q->ValidatingResponse) 1739 { 1740 const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; 1741 rdataRRSig *rrsig = (rdataRRSig *)rdb->data; 1742 mDNSu16 typeCovered = swap16(rrsig->typeCovered); 1743 debugf("DNSSECRecordAnswersQuestion: Matching RRSIG typeCovered %s", DNSTypeName(typeCovered)); 1744 if (typeCovered != kDNSType_CNAME && typeCovered != q->qtype) 1745 { 1746 debugf("DNSSECRecordAnswersQuestion: RRSIG did not match question %##s (%s)", q->qname.c, 1747 DNSTypeName(q->qtype)); 1748 return mDNSfalse; 1749 } 1750 LogInfo("DNSSECRecordAnswersQuestion: RRSIG matched question %##s (%s)", q->qname.c, 1751 DNSTypeName(q->qtype)); 1752 *checkType = mDNSfalse; 1753 return mDNStrue; 1754 } 1755 // If the NSEC record asserts the non-existence of a name looked up by the question, we would 1756 // typically answer that e.g., the bitmap asserts that q->qtype does not exist. If we have 1757 // to prove the non-existence as required by ValidatingResponse and ValidationRequired question, 1758 // then we should not answer that as it may not be the right one always. We may need more than 1759 // one NSEC to prove the non-existence. 1760 if (rr->rrtype == kDNSType_NSEC && DNSSECQuestion(q)) 1761 { 1762 debugf("DNSSECRecordAnswersQuestion: Question %##s (%s) matched record %##s (NSEC)", q->qname.c, 1763 DNSTypeName(q->qtype), rr->name->c); 1764 return mDNSfalse; 1765 } 1766 return mDNStrue; 1767 } 1768 1769 // ResourceRecordAnswersQuestion returns mDNStrue if the given resource record is a valid answer to the given question. 1770 // SameNameRecordAnswersQuestion is the same, except it skips the expensive SameDomainName() call. 1771 // SameDomainName() is generally cheap when the names don't match, but expensive when they do match, 1772 // because it has to check all the way to the end of the names to be sure. 1773 // In cases where we know in advance that the names match it's especially advantageous to skip the 1774 // SameDomainName() call because that's precisely the time when it's most expensive and least useful. 1775 1776 mDNSexport mDNSBool SameNameRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q) 1777 { 1778 mDNSBool checkType = mDNStrue; 1779 1780 // LocalOnly/P2P questions can be answered with AuthRecordAny in this function. LocalOnly/P2P records 1781 // are handled in LocalOnlyRecordAnswersQuestion 1782 if ((rr->InterfaceID == mDNSInterface_LocalOnly) || (rr->InterfaceID == mDNSInterface_P2P)) 1783 { 1784 LogMsg("SameNameRecordAnswersQuestion: ERROR!! called with LocalOnly ResourceRecord %p, Question %p", rr->InterfaceID, q->InterfaceID); 1785 return mDNSfalse; 1786 } 1787 if (QuerySuppressed(q)) 1788 return mDNSfalse; 1789 1790 if (rr->InterfaceID && 1791 q->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly && 1792 rr->InterfaceID != q->InterfaceID) return(mDNSfalse); 1793 1794 // Resource record received via unicast, the resolver group ID should match ? 1795 if (!rr->InterfaceID) 1796 { 1797 mDNSu16 idr = (rr->rDNSServer ? rr->rDNSServer->resGroupID : 0); 1798 mDNSu16 idq = (q->qDNSServer ? q->qDNSServer->resGroupID : 0); 1799 if (idr != idq) return(mDNSfalse); 1800 if (!DNSSECRecordAnswersQuestion(rr, q, &checkType)) return mDNSfalse; 1801 } 1802 1803 // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question 1804 if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); 1805 1806 // CNAME answers question of any type and a negative cache record should not prevent us from querying other 1807 // valid types at the same name. 1808 if (rr->rrtype == kDNSType_CNAME && rr->RecordType == kDNSRecordTypePacketNegative && rr->rrtype != q->qtype) 1809 return mDNSfalse; 1810 1811 // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class. 1812 if (checkType && !RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse); 1813 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); 1814 1815 #if APPLE_OSX_mDNSResponder 1816 if (!mDNSPlatformValidRecordForQuestion(rr, q)) 1817 return mDNSfalse; 1818 #endif // APPLE_OSX_mDNSResponder 1819 1820 if (!AnonInfoAnswersQuestion(rr, q)) 1821 return mDNSfalse; 1822 1823 return(mDNStrue); 1824 } 1825 1826 mDNSexport mDNSBool ResourceRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q) 1827 { 1828 if (!SameNameRecordAnswersQuestion(rr, q)) 1829 return mDNSfalse; 1830 1831 return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); 1832 } 1833 1834 // We have a separate function to handle LocalOnly AuthRecords because they can be created with 1835 // a valid InterfaceID (e.g., scoped /etc/hosts) and can be used to answer unicast questions unlike 1836 // multicast resource records (which has a valid InterfaceID) which can't be used to answer 1837 // unicast questions. ResourceRecordAnswersQuestion/SameNameRecordAnswersQuestion can't tell whether 1838 // a resource record is multicast or LocalOnly by just looking at the ResourceRecord because 1839 // LocalOnly records are truly identified by ARType in the AuthRecord. As P2P and LocalOnly record 1840 // are kept in the same hash table, we use the same function to make it easy for the callers when 1841 // they walk the hash table to answer LocalOnly/P2P questions 1842 // 1843 mDNSexport mDNSBool LocalOnlyRecordAnswersQuestion(AuthRecord *const ar, const DNSQuestion *const q) 1844 { 1845 ResourceRecord *rr = &ar->resrec; 1846 1847 // mDNSInterface_Any questions can be answered with LocalOnly/P2P records in this function. AuthRecord_Any 1848 // records are handled in ResourceRecordAnswersQuestion/SameNameRecordAnswersQuestion 1849 if (RRAny(ar)) 1850 { 1851 LogMsg("LocalOnlyRecordAnswersQuestion: ERROR!! called with regular AuthRecordAny %##s", rr->name->c); 1852 return mDNSfalse; 1853 } 1854 1855 // Questions with mDNSInterface_LocalOnly InterfaceID should be answered with all resource records that are 1856 // *local* to the machine. These include resource records that have InterfaceID set to mDNSInterface_LocalOnly, 1857 // mDNSInterface_Any and any other real InterfaceID. Hence, LocalOnly questions should not be checked against 1858 // the InterfaceID in the resource record. 1859 // 1860 // mDNSInterface_Unicast does not indicate any scope and hence treat them like mDNSInterface_Any. 1861 1862 if (rr->InterfaceID && 1863 q->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly && q->InterfaceID != mDNSInterface_Unicast && 1864 rr->InterfaceID != q->InterfaceID) return(mDNSfalse); 1865 1866 // Entries in /etc/hosts are added as LocalOnly resource records. The LocalOnly resource records 1867 // may have a scope e.g., fe80::1%en0. The question may be scoped or not: the InterfaceID may be set 1868 // to mDNSInterface_Any, mDNSInterface_LocalOnly or a real InterfaceID (scoped). 1869 // 1870 // 1) Question: Any, LocalOnly Record: no scope. This question should be answered with this record. 1871 // 1872 // 2) Question: Any, LocalOnly Record: scoped. This question should be answered with the record because 1873 // traditionally applications never specify scope e.g., getaddrinfo, but need to be able 1874 // to get to /etc/hosts entries. 1875 // 1876 // 3) Question: Scoped (LocalOnly or InterfaceID), LocalOnly Record: no scope. This is the inverse of (2). 1877 // If we register a LocalOnly record, we need to answer a LocalOnly question. If the /etc/hosts has a 1878 // non scoped entry, it may not make sense to answer a scoped question. But we can't tell these two 1879 // cases apart. As we currently answer LocalOnly question with LocalOnly record, we continue to do so. 1880 // 1881 // 4) Question: Scoped (LocalOnly or InterfaceID), LocalOnly Record: scoped. LocalOnly questions should be 1882 // answered with any resource record where as if it has a valid InterfaceID, the scope should match. 1883 // 1884 // (1) and (2) is bypassed because we check for a non-NULL InterfaceID above. For (3), the InterfaceID is NULL 1885 // and hence bypassed above. For (4) we bypassed LocalOnly questions and checked the scope of the record 1886 // against the question. 1887 // 1888 // For P2P, InterfaceIDs of the question and the record should match. 1889 1890 // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question. 1891 // LocalOnly authoritative answers are exempt. LocalOnly authoritative answers are used for /etc/host entries. 1892 // We don't want a local process to be able to create a fake LocalOnly address record for "www.bigbank.com" which would then 1893 // cause other applications (e.g. Safari) to connect to the wrong address. The rpc to register records filters out records 1894 // with names that don't end in local and have mDNSInterface_LocalOnly set. 1895 // 1896 // Note: The check is bypassed for LocalOnly and for P2P it is not needed as only .local records are registered and for 1897 // a question to match its names, it also has to end in .local and that question can't be a unicast question (See 1898 // Question_uDNS macro and its usage). As P2P does not enforce .local only registrations we still make this check 1899 // and also makes it future proof. 1900 1901 if (ar->ARType != AuthRecordLocalOnly && rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); 1902 1903 // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class. 1904 if (!RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse); 1905 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); 1906 1907 if (!AnonInfoAnswersQuestion(rr, q)) 1908 return mDNSfalse; 1909 1910 return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); 1911 } 1912 1913 mDNSexport mDNSBool AnyTypeRecordAnswersQuestion(const ResourceRecord *const rr, const DNSQuestion *const q) 1914 { 1915 // LocalOnly/P2P questions can be answered with AuthRecordAny in this function. LocalOnly/P2P records 1916 // are handled in LocalOnlyRecordAnswersQuestion 1917 if ((rr->InterfaceID == mDNSInterface_LocalOnly) || (rr->InterfaceID == mDNSInterface_P2P)) 1918 { 1919 LogMsg("AnyTypeRecordAnswersQuestion: ERROR!! called with LocalOnly ResourceRecord %p, Question %p", rr->InterfaceID, q->InterfaceID); 1920 return mDNSfalse; 1921 } 1922 if (rr->InterfaceID && 1923 q->InterfaceID && q->InterfaceID != mDNSInterface_LocalOnly && 1924 rr->InterfaceID != q->InterfaceID) return(mDNSfalse); 1925 1926 // Resource record received via unicast, the resolver group ID should match ? 1927 // Note that Auth Records are normally setup with NULL InterfaceID and 1928 // both the DNSServers are assumed to be NULL in that case 1929 if (!rr->InterfaceID) 1930 { 1931 mDNSu16 idr = (rr->rDNSServer ? rr->rDNSServer->resGroupID : 0); 1932 mDNSu16 idq = (q->qDNSServer ? q->qDNSServer->resGroupID : 0); 1933 if (idr != idq) return(mDNSfalse); 1934 } 1935 1936 // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question 1937 if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); 1938 1939 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); 1940 1941 if (!AnonInfoAnswersQuestion(rr, q)) 1942 return mDNSfalse; 1943 1944 return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); 1945 } 1946 1947 // This is called with both unicast resource record and multicast resource record. The question that 1948 // received the unicast response could be the regular unicast response from a DNS server or a response 1949 // to a mDNS QU query. The main reason we need this function is that we can't compare DNSServers between the 1950 // question and the resource record because the resource record is not completely initialized in 1951 // mDNSCoreReceiveResponse when this function is called. 1952 mDNSexport mDNSBool ResourceRecordAnswersUnicastResponse(const ResourceRecord *const rr, const DNSQuestion *const q) 1953 { 1954 mDNSBool checkType = mDNStrue; 1955 1956 if (QuerySuppressed(q)) 1957 return mDNSfalse; 1958 1959 // For resource records created using multicast, the InterfaceIDs have to match 1960 if (rr->InterfaceID && 1961 q->InterfaceID && rr->InterfaceID != q->InterfaceID) return(mDNSfalse); 1962 1963 // If ResourceRecord received via multicast, but question was unicast, then shouldn't use record to answer this question. 1964 if (rr->InterfaceID && !mDNSOpaque16IsZero(q->TargetQID)) return(mDNSfalse); 1965 1966 if (!DNSSECRecordAnswersQuestion(rr, q, &checkType)) return mDNSfalse; 1967 1968 // RR type CNAME matches any query type. QTYPE ANY matches any RR type. QCLASS ANY matches any RR class. 1969 if (checkType && !RRTypeAnswersQuestionType(rr,q->qtype)) return(mDNSfalse); 1970 1971 if (rr->rrclass != q->qclass && q->qclass != kDNSQClass_ANY) return(mDNSfalse); 1972 1973 return(rr->namehash == q->qnamehash && SameDomainName(rr->name, &q->qname)); 1974 } 1975 1976 mDNSexport mDNSu16 GetRDLength(const ResourceRecord *const rr, mDNSBool estimate) 1977 { 1978 const RDataBody2 *const rd = (RDataBody2 *)rr->rdata->u.data; 1979 const domainname *const name = estimate ? rr->name : mDNSNULL; 1980 if (rr->rrclass == kDNSQClass_ANY) return(rr->rdlength); // Used in update packets to mean "Delete An RRset" (RFC 2136) 1981 else switch (rr->rrtype) 1982 { 1983 case kDNSType_A: return(sizeof(rd->ipv4)); 1984 1985 case kDNSType_NS: 1986 case kDNSType_CNAME: 1987 case kDNSType_PTR: 1988 case kDNSType_DNAME: return(CompressedDomainNameLength(&rd->name, name)); 1989 1990 case kDNSType_SOA: return (mDNSu16)(CompressedDomainNameLength(&rd->soa.mname, name) + 1991 CompressedDomainNameLength(&rd->soa.rname, name) + 1992 5 * sizeof(mDNSOpaque32)); 1993 1994 case kDNSType_NULL: 1995 case kDNSType_TSIG: 1996 case kDNSType_TXT: 1997 case kDNSType_X25: 1998 case kDNSType_ISDN: 1999 case kDNSType_LOC: 2000 case kDNSType_DHCID: return(rr->rdlength); // Not self-describing, so have to just trust rdlength 2001 2002 case kDNSType_HINFO: return (mDNSu16)(2 + (int)rd->data[0] + (int)rd->data[1 + (int)rd->data[0]]); 2003 2004 case kDNSType_MX: 2005 case kDNSType_AFSDB: 2006 case kDNSType_RT: 2007 case kDNSType_KX: return (mDNSu16)(2 + CompressedDomainNameLength(&rd->mx.exchange, name)); 2008 2009 case kDNSType_RP: return (mDNSu16)(CompressedDomainNameLength(&rd->rp.mbox, name) + 2010 CompressedDomainNameLength(&rd->rp.txt, name)); 2011 2012 case kDNSType_PX: return (mDNSu16)(2 + CompressedDomainNameLength(&rd->px.map822, name) + 2013 CompressedDomainNameLength(&rd->px.mapx400, name)); 2014 2015 case kDNSType_AAAA: return(sizeof(rd->ipv6)); 2016 2017 case kDNSType_SRV: return (mDNSu16)(6 + CompressedDomainNameLength(&rd->srv.target, name)); 2018 2019 case kDNSType_OPT: return(rr->rdlength); 2020 2021 case kDNSType_NSEC: { 2022 domainname *next = (domainname *)rd->data; 2023 int dlen = DomainNameLength(next); 2024 // 2025 if (UNICAST_NSEC(rr)) 2026 return (mDNSu16)(CompressedDomainNameLength(next, name) + rr->rdlength - dlen); 2027 else 2028 return (mDNSu16)((estimate ? 2 : dlen) + rr->rdlength - dlen); 2029 } 2030 2031 default: debugf("Warning! Don't know how to get length of resource type %d", rr->rrtype); 2032 return(rr->rdlength); 2033 } 2034 } 2035 2036 // When a local client registers (or updates) a record, we use this routine to do some simple validation checks 2037 // to help reduce the risk of bogus malformed data on the network 2038 mDNSexport mDNSBool ValidateRData(const mDNSu16 rrtype, const mDNSu16 rdlength, const RData *const rd) 2039 { 2040 mDNSu16 len; 2041 2042 switch(rrtype) 2043 { 2044 case kDNSType_A: return(rdlength == sizeof(mDNSv4Addr)); 2045 2046 case kDNSType_NS: // Same as PTR 2047 case kDNSType_MD: // Same as PTR 2048 case kDNSType_MF: // Same as PTR 2049 case kDNSType_CNAME: // Same as PTR 2050 //case kDNSType_SOA not checked 2051 case kDNSType_MB: // Same as PTR 2052 case kDNSType_MG: // Same as PTR 2053 case kDNSType_MR: // Same as PTR 2054 //case kDNSType_NULL not checked (no specified format, so always valid) 2055 //case kDNSType_WKS not checked 2056 case kDNSType_PTR: len = DomainNameLengthLimit(&rd->u.name, rd->u.data + rdlength); 2057 return(len <= MAX_DOMAIN_NAME && rdlength == len); 2058 2059 case kDNSType_HINFO: // Same as TXT (roughly) 2060 case kDNSType_MINFO: // Same as TXT (roughly) 2061 case kDNSType_TXT: if (!rdlength) return(mDNSfalse); // TXT record has to be at least one byte (RFC 1035) 2062 { 2063 const mDNSu8 *ptr = rd->u.txt.c; 2064 const mDNSu8 *end = rd->u.txt.c + rdlength; 2065 while (ptr < end) ptr += 1 + ptr[0]; 2066 return (ptr == end); 2067 } 2068 2069 case kDNSType_AAAA: return(rdlength == sizeof(mDNSv6Addr)); 2070 2071 case kDNSType_MX: // Must be at least two-byte preference, plus domainname 2072 // Call to DomainNameLengthLimit() implicitly enforces both requirements for us 2073 len = DomainNameLengthLimit(&rd->u.mx.exchange, rd->u.data + rdlength); 2074 return(len <= MAX_DOMAIN_NAME && rdlength == 2+len); 2075 2076 case kDNSType_SRV: // Must be at least priority+weight+port, plus domainname 2077 // Call to DomainNameLengthLimit() implicitly enforces both requirements for us 2078 len = DomainNameLengthLimit(&rd->u.srv.target, rd->u.data + rdlength); 2079 return(len <= MAX_DOMAIN_NAME && rdlength == 6+len); 2080 2081 //case kDNSType_NSEC not checked 2082 2083 default: return(mDNStrue); // Allow all other types without checking 2084 } 2085 } 2086 2087 // *************************************************************************** 2088 #if COMPILER_LIKES_PRAGMA_MARK 2089 #pragma mark - 2090 #pragma mark - DNS Message Creation Functions 2091 #endif 2092 2093 mDNSexport void InitializeDNSMessage(DNSMessageHeader *h, mDNSOpaque16 id, mDNSOpaque16 flags) 2094 { 2095 h->id = id; 2096 h->flags = flags; 2097 h->numQuestions = 0; 2098 h->numAnswers = 0; 2099 h->numAuthorities = 0; 2100 h->numAdditionals = 0; 2101 } 2102 2103 mDNSexport const mDNSu8 *FindCompressionPointer(const mDNSu8 *const base, const mDNSu8 *const end, const mDNSu8 *const domname) 2104 { 2105 const mDNSu8 *result = end - *domname - 1; 2106 2107 if (*domname == 0) return(mDNSNULL); // There's no point trying to match just the root label 2108 2109 // This loop examines each possible starting position in packet, starting end of the packet and working backwards 2110 while (result >= base) 2111 { 2112 // If the length byte and first character of the label match, then check further to see 2113 // if this location in the packet will yield a useful name compression pointer. 2114 if (result[0] == domname[0] && result[1] == domname[1]) 2115 { 2116 const mDNSu8 *name = domname; 2117 const mDNSu8 *targ = result; 2118 while (targ + *name < end) 2119 { 2120 // First see if this label matches 2121 int i; 2122 const mDNSu8 *pointertarget; 2123 for (i=0; i <= *name; i++) if (targ[i] != name[i]) break; 2124 if (i <= *name) break; // If label did not match, bail out 2125 targ += 1 + *name; // Else, did match, so advance target pointer 2126 name += 1 + *name; // and proceed to check next label 2127 if (*name == 0 && *targ == 0) return(result); // If no more labels, we found a match! 2128 if (*name == 0) break; // If no more labels to match, we failed, so bail out 2129 2130 // The label matched, so now follow the pointer (if appropriate) and then see if the next label matches 2131 if (targ[0] < 0x40) continue; // If length value, continue to check next label 2132 if (targ[0] < 0xC0) break; // If 40-BF, not valid 2133 if (targ+1 >= end) break; // Second byte not present! 2134 pointertarget = base + (((mDNSu16)(targ[0] & 0x3F)) << 8) + targ[1]; 2135 if (targ < pointertarget) break; // Pointertarget must point *backwards* in the packet 2136 if (pointertarget[0] >= 0x40) break; // Pointertarget must point to a valid length byte 2137 targ = pointertarget; 2138 } 2139 } 2140 result--; // We failed to match at this search position, so back up the tentative result pointer and try again 2141 } 2142 return(mDNSNULL); 2143 } 2144 2145 // Put a string of dot-separated labels as length-prefixed labels 2146 // domainname is a fully-qualified name (i.e. assumed to be ending in a dot, even if it doesn't) 2147 // msg points to the message we're building (pass mDNSNULL if we don't want to use compression pointers) 2148 // end points to the end of the message so far 2149 // ptr points to where we want to put the name 2150 // limit points to one byte past the end of the buffer that we must not overrun 2151 // domainname is the name to put 2152 mDNSexport mDNSu8 *putDomainNameAsLabels(const DNSMessage *const msg, 2153 mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name) 2154 { 2155 const mDNSu8 *const base = (const mDNSu8 *)msg; 2156 const mDNSu8 * np = name->c; 2157 const mDNSu8 *const max = name->c + MAX_DOMAIN_NAME; // Maximum that's valid 2158 const mDNSu8 * pointer = mDNSNULL; 2159 const mDNSu8 *const searchlimit = ptr; 2160 2161 if (!ptr) { LogMsg("putDomainNameAsLabels %##s ptr is null", name->c); return(mDNSNULL); } 2162 2163 if (!*np) // If just writing one-byte root label, make sure we have space for that 2164 { 2165 if (ptr >= limit) return(mDNSNULL); 2166 } 2167 else // else, loop through writing labels and/or a compression offset 2168 { 2169 do { 2170 if (*np > MAX_DOMAIN_LABEL) 2171 { LogMsg("Malformed domain name %##s (label more than 63 bytes)", name->c); return(mDNSNULL); } 2172 2173 // This check correctly allows for the final trailing root label: 2174 // e.g. 2175 // Suppose our domain name is exactly 256 bytes long, including the final trailing root label. 2176 // Suppose np is now at name->c[249], and we're about to write our last non-null label ("local"). 2177 // We know that max will be at name->c[256] 2178 // That means that np + 1 + 5 == max - 1, so we (just) pass the "if" test below, write our 2179 // six bytes, then exit the loop, write the final terminating root label, and the domain 2180 // name we've written is exactly 256 bytes long, exactly at the correct legal limit. 2181 // If the name is one byte longer, then we fail the "if" test below, and correctly bail out. 2182 if (np + 1 + *np >= max) 2183 { LogMsg("Malformed domain name %##s (more than 256 bytes)", name->c); return(mDNSNULL); } 2184 2185 if (base) pointer = FindCompressionPointer(base, searchlimit, np); 2186 if (pointer) // Use a compression pointer if we can 2187 { 2188 const mDNSu16 offset = (mDNSu16)(pointer - base); 2189 if (ptr+2 > limit) return(mDNSNULL); // If we don't have two bytes of space left, give up 2190 *ptr++ = (mDNSu8)(0xC0 | (offset >> 8)); 2191 *ptr++ = (mDNSu8)( offset & 0xFF); 2192 return(ptr); 2193 } 2194 else // Else copy one label and try again 2195 { 2196 int i; 2197 mDNSu8 len = *np++; 2198 // If we don't at least have enough space for this label *plus* a terminating zero on the end, give up 2199 if (ptr + 1 + len >= limit) return(mDNSNULL); 2200 *ptr++ = len; 2201 for (i=0; i<len; i++) *ptr++ = *np++; 2202 } 2203 } while (*np); // While we've got characters remaining in the name, continue 2204 } 2205 2206 *ptr++ = 0; // Put the final root label 2207 return(ptr); 2208 } 2209 2210 mDNSlocal mDNSu8 *putVal16(mDNSu8 *ptr, mDNSu16 val) 2211 { 2212 ptr[0] = (mDNSu8)((val >> 8 ) & 0xFF); 2213 ptr[1] = (mDNSu8)((val ) & 0xFF); 2214 return ptr + sizeof(mDNSOpaque16); 2215 } 2216 2217 mDNSlocal mDNSu8 *putVal32(mDNSu8 *ptr, mDNSu32 val) 2218 { 2219 ptr[0] = (mDNSu8)((val >> 24) & 0xFF); 2220 ptr[1] = (mDNSu8)((val >> 16) & 0xFF); 2221 ptr[2] = (mDNSu8)((val >> 8) & 0xFF); 2222 ptr[3] = (mDNSu8)((val ) & 0xFF); 2223 return ptr + sizeof(mDNSu32); 2224 } 2225 2226 // Copy the RDATA information. The actual in memory storage for the data might be bigger than what the rdlength 2227 // says. Hence, the only way to copy out the data from a resource record is to use putRData. 2228 // msg points to the message we're building (pass mDNSNULL for "msg" if we don't want to use compression pointers) 2229 mDNSexport mDNSu8 *putRData(const DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const ResourceRecord *const rr) 2230 { 2231 const RDataBody2 *const rdb = (RDataBody2 *)rr->rdata->u.data; 2232 switch (rr->rrtype) 2233 { 2234 case kDNSType_A: if (rr->rdlength != 4) 2235 { debugf("putRData: Illegal length %d for kDNSType_A", rr->rdlength); return(mDNSNULL); } 2236 if (ptr + 4 > limit) return(mDNSNULL); 2237 *ptr++ = rdb->ipv4.b[0]; 2238 *ptr++ = rdb->ipv4.b[1]; 2239 *ptr++ = rdb->ipv4.b[2]; 2240 *ptr++ = rdb->ipv4.b[3]; 2241 return(ptr); 2242 2243 case kDNSType_NS: 2244 case kDNSType_CNAME: 2245 case kDNSType_PTR: 2246 case kDNSType_DNAME: return(putDomainNameAsLabels(msg, ptr, limit, &rdb->name)); 2247 2248 case kDNSType_SOA: ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->soa.mname); 2249 if (!ptr) return(mDNSNULL); 2250 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->soa.rname); 2251 if (!ptr || ptr + 20 > limit) return(mDNSNULL); 2252 ptr = putVal32(ptr, rdb->soa.serial); 2253 ptr = putVal32(ptr, rdb->soa.refresh); 2254 ptr = putVal32(ptr, rdb->soa.retry); 2255 ptr = putVal32(ptr, rdb->soa.expire); 2256 ptr = putVal32(ptr, rdb->soa.min); 2257 return(ptr); 2258 2259 case kDNSType_NULL: 2260 case kDNSType_HINFO: 2261 case kDNSType_TSIG: 2262 case kDNSType_TXT: 2263 case kDNSType_X25: 2264 case kDNSType_ISDN: 2265 case kDNSType_LOC: 2266 case kDNSType_DHCID: if (ptr + rr->rdlength > limit) return(mDNSNULL); 2267 mDNSPlatformMemCopy(ptr, rdb->data, rr->rdlength); 2268 return(ptr + rr->rdlength); 2269 2270 case kDNSType_MX: 2271 case kDNSType_AFSDB: 2272 case kDNSType_RT: 2273 case kDNSType_KX: if (ptr + 3 > limit) return(mDNSNULL); 2274 ptr = putVal16(ptr, rdb->mx.preference); 2275 return(putDomainNameAsLabels(msg, ptr, limit, &rdb->mx.exchange)); 2276 2277 case kDNSType_RP: ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->rp.mbox); 2278 if (!ptr) return(mDNSNULL); 2279 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->rp.txt); 2280 return(ptr); 2281 2282 case kDNSType_PX: if (ptr + 5 > limit) return(mDNSNULL); 2283 ptr = putVal16(ptr, rdb->px.preference); 2284 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->px.map822); 2285 if (!ptr) return(mDNSNULL); 2286 ptr = putDomainNameAsLabels(msg, ptr, limit, &rdb->px.mapx400); 2287 return(ptr); 2288 2289 case kDNSType_AAAA: if (rr->rdlength != sizeof(rdb->ipv6)) 2290 { debugf("putRData: Illegal length %d for kDNSType_AAAA", rr->rdlength); return(mDNSNULL); } 2291 if (ptr + sizeof(rdb->ipv6) > limit) return(mDNSNULL); 2292 mDNSPlatformMemCopy(ptr, &rdb->ipv6, sizeof(rdb->ipv6)); 2293 return(ptr + sizeof(rdb->ipv6)); 2294 2295 case kDNSType_SRV: if (ptr + 7 > limit) return(mDNSNULL); 2296 *ptr++ = (mDNSu8)(rdb->srv.priority >> 8); 2297 *ptr++ = (mDNSu8)(rdb->srv.priority & 0xFF); 2298 *ptr++ = (mDNSu8)(rdb->srv.weight >> 8); 2299 *ptr++ = (mDNSu8)(rdb->srv.weight & 0xFF); 2300 *ptr++ = rdb->srv.port.b[0]; 2301 *ptr++ = rdb->srv.port.b[1]; 2302 return(putDomainNameAsLabels(msg, ptr, limit, &rdb->srv.target)); 2303 2304 case kDNSType_OPT: { 2305 int len = 0; 2306 const rdataOPT *opt; 2307 const rdataOPT *const end = (const rdataOPT *)&rr->rdata->u.data[rr->rdlength]; 2308 for (opt = &rr->rdata->u.opt[0]; opt < end; opt++) 2309 len += DNSOpt_Data_Space(opt); 2310 if (ptr + len > limit) 2311 { 2312 LogMsg("ERROR: putOptRData - out of space"); 2313 return mDNSNULL; 2314 } 2315 for (opt = &rr->rdata->u.opt[0]; opt < end; opt++) 2316 { 2317 const int space = DNSOpt_Data_Space(opt); 2318 ptr = putVal16(ptr, opt->opt); 2319 ptr = putVal16(ptr, (mDNSu16)space - 4); 2320 switch (opt->opt) 2321 { 2322 case kDNSOpt_LLQ: 2323 ptr = putVal16(ptr, opt->u.llq.vers); 2324 ptr = putVal16(ptr, opt->u.llq.llqOp); 2325 ptr = putVal16(ptr, opt->u.llq.err); 2326 mDNSPlatformMemCopy(ptr, opt->u.llq.id.b, 8); // 8-byte id 2327 ptr += 8; 2328 ptr = putVal32(ptr, opt->u.llq.llqlease); 2329 break; 2330 case kDNSOpt_Lease: 2331 ptr = putVal32(ptr, opt->u.updatelease); 2332 break; 2333 case kDNSOpt_Owner: 2334 *ptr++ = opt->u.owner.vers; 2335 *ptr++ = opt->u.owner.seq; 2336 mDNSPlatformMemCopy(ptr, opt->u.owner.HMAC.b, 6); // 6-byte Host identifier 2337 ptr += 6; 2338 if (space >= DNSOpt_OwnerData_ID_Wake_Space) 2339 { 2340 mDNSPlatformMemCopy(ptr, opt->u.owner.IMAC.b, 6); // 6-byte interface MAC 2341 ptr += 6; 2342 if (space > DNSOpt_OwnerData_ID_Wake_Space) 2343 { 2344 mDNSPlatformMemCopy(ptr, opt->u.owner.password.b, space - DNSOpt_OwnerData_ID_Wake_Space); 2345 ptr += space - DNSOpt_OwnerData_ID_Wake_Space; 2346 } 2347 } 2348 break; 2349 case kDNSOpt_Trace: 2350 *ptr++ = opt->u.tracer.platf; 2351 ptr = putVal32(ptr, opt->u.tracer.mDNSv); 2352 break; 2353 } 2354 } 2355 return ptr; 2356 } 2357 2358 case kDNSType_NSEC: { 2359 // For NSEC records, rdlength represents the exact number of bytes 2360 // of in memory storage. 2361 mDNSu8 *nsec = (mDNSu8 *)rdb->data; 2362 domainname *name = (domainname *)nsec; 2363 const int dlen = DomainNameLength(name); 2364 nsec += dlen; 2365 // This function is called when we are sending a NSEC record as part of mDNS, 2366 // or to copy the data to any other buffer needed which could be a mDNS or uDNS 2367 // NSEC record. The only time compression is used that when we are sending it 2368 // in mDNS (indicated by non-NULL "msg") and hence we handle mDNS case 2369 // separately. 2370 if (!UNICAST_NSEC(rr)) 2371 { 2372 mDNSu8 *save = ptr; 2373 int i, j, wlen; 2374 wlen = *(nsec + 1); 2375 nsec += 2; // Skip the window number and len 2376 2377 // For our simplified use of NSEC synthetic records: 2378 // 2379 // nextname is always the record's own name, 2380 // the block number is always 0, 2381 // the count byte is a value in the range 1-32, 2382 // followed by the 1-32 data bytes 2383 // 2384 // Note: When we send the NSEC record in mDNS, the window size is set to 32. 2385 // We need to find out what the last non-NULL byte is. If we are copying out 2386 // from an RDATA, we have the right length. As we need to handle both the case, 2387 // we loop to find the right value instead of blindly using len to copy. 2388 2389 for (i=wlen; i>0; i--) if (nsec[i-1]) break; 2390 2391 ptr = putDomainNameAsLabels(msg, ptr, limit, rr->name); 2392 if (!ptr) { LogInfo("putRData: Can't put name, Length %d, record %##s", limit - save, rr->name->c); return(mDNSNULL); } 2393 if (i) // Only put a block if at least one type exists for this name 2394 { 2395 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); } 2396 *ptr++ = 0; 2397 *ptr++ = (mDNSu8)i; 2398 for (j=0; j<i; j++) *ptr++ = nsec[j]; 2399 } 2400 return ptr; 2401 } 2402 else 2403 { 2404 int win, wlen; 2405 int len = rr->rdlength - dlen; 2406 2407 // Sanity check whether the bitmap is good 2408 while (len) 2409 { 2410 if (len < 3) 2411 { LogMsg("putRData: invalid length %d", len); return mDNSNULL; } 2412 2413 win = *nsec++; 2414 wlen = *nsec++; 2415 len -= 2; 2416 if (len < wlen || wlen < 1 || wlen > 32) 2417 { LogMsg("putRData: invalid window length %d", wlen); return mDNSNULL; } 2418 if (win < 0 || win >= 256) 2419 { LogMsg("putRData: invalid window %d", win); return mDNSNULL; } 2420 2421 nsec += wlen; 2422 len -= wlen; 2423 } 2424 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);} 2425 2426 // No compression allowed for "nxt", just copy the data. 2427 mDNSPlatformMemCopy(ptr, rdb->data, rr->rdlength); 2428 return(ptr + rr->rdlength); 2429 } 2430 } 2431 2432 default: debugf("putRData: Warning! Writing unknown resource type %d as raw data", rr->rrtype); 2433 if (ptr + rr->rdlength > limit) return(mDNSNULL); 2434 mDNSPlatformMemCopy(ptr, rdb->data, rr->rdlength); 2435 return(ptr + rr->rdlength); 2436 } 2437 } 2438 2439 #define IsUnicastUpdate(X) (!mDNSOpaque16IsZero((X)->h.id) && ((X)->h.flags.b[0] & kDNSFlag0_OP_Mask) == kDNSFlag0_OP_Update) 2440 2441 mDNSexport mDNSu8 *PutResourceRecordTTLWithLimit(DNSMessage *const msg, mDNSu8 *ptr, mDNSu16 *count, ResourceRecord *rr, mDNSu32 ttl, const mDNSu8 *limit) 2442 { 2443 mDNSu8 *endofrdata; 2444 mDNSu16 actualLength; 2445 // When sending SRV to conventional DNS server (i.e. in DNS update requests) we should not do name compression on the rdata (RFC 2782) 2446 const DNSMessage *const rdatacompressionbase = (IsUnicastUpdate(msg) && rr->rrtype == kDNSType_SRV) ? mDNSNULL : msg; 2447 2448 if (rr->RecordType == kDNSRecordTypeUnregistered) 2449 { 2450 LogMsg("PutResourceRecordTTLWithLimit ERROR! Attempt to put kDNSRecordTypeUnregistered %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype)); 2451 return(ptr); 2452 } 2453 2454 if (!ptr) 2455 { 2456 LogMsg("PutResourceRecordTTLWithLimit ptr is null %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype)); 2457 return(mDNSNULL); 2458 } 2459 2460 ptr = putDomainNameAsLabels(msg, ptr, limit, rr->name); 2461 // If we're out-of-space, return mDNSNULL 2462 if (!ptr || ptr + 10 >= limit) 2463 { 2464 LogInfo("PutResourceRecordTTLWithLimit: can't put name, out of space %##s (%s), ptr %p, limit %p", rr->name->c, 2465 DNSTypeName(rr->rrtype), ptr, limit); 2466 return(mDNSNULL); 2467 } 2468 ptr[0] = (mDNSu8)(rr->rrtype >> 8); 2469 ptr[1] = (mDNSu8)(rr->rrtype & 0xFF); 2470 ptr[2] = (mDNSu8)(rr->rrclass >> 8); 2471 ptr[3] = (mDNSu8)(rr->rrclass & 0xFF); 2472 ptr[4] = (mDNSu8)((ttl >> 24) & 0xFF); 2473 ptr[5] = (mDNSu8)((ttl >> 16) & 0xFF); 2474 ptr[6] = (mDNSu8)((ttl >> 8) & 0xFF); 2475 ptr[7] = (mDNSu8)( ttl & 0xFF); 2476 // ptr[8] and ptr[9] filled in *after* we find out how much space the rdata takes 2477 2478 endofrdata = putRData(rdatacompressionbase, ptr+10, limit, rr); 2479 if (!endofrdata) 2480 { 2481 LogInfo("PutResourceRecordTTLWithLimit: Ran out of space in PutResourceRecord for %##s (%s), ptr %p, limit %p", rr->name->c, 2482 DNSTypeName(rr->rrtype), ptr+10, limit); 2483 return(mDNSNULL); 2484 } 2485 2486 // Go back and fill in the actual number of data bytes we wrote 2487 // (actualLength can be less than rdlength when domain name compression is used) 2488 actualLength = (mDNSu16)(endofrdata - ptr - 10); 2489 ptr[8] = (mDNSu8)(actualLength >> 8); 2490 ptr[9] = (mDNSu8)(actualLength & 0xFF); 2491 2492 if (count) (*count)++; 2493 else LogMsg("PutResourceRecordTTL: ERROR: No target count to update for %##s (%s)", rr->name->c, DNSTypeName(rr->rrtype)); 2494 return(endofrdata); 2495 } 2496 2497 mDNSlocal mDNSu8 *putEmptyResourceRecord(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, mDNSu16 *count, const AuthRecord *rr) 2498 { 2499 ptr = putDomainNameAsLabels(msg, ptr, limit, rr->resrec.name); 2500 if (!ptr || ptr + 10 > limit) return(mDNSNULL); // If we're out-of-space, return mDNSNULL 2501 ptr[0] = (mDNSu8)(rr->resrec.rrtype >> 8); // Put type 2502 ptr[1] = (mDNSu8)(rr->resrec.rrtype & 0xFF); 2503 ptr[2] = (mDNSu8)(rr->resrec.rrclass >> 8); // Put class 2504 ptr[3] = (mDNSu8)(rr->resrec.rrclass & 0xFF); 2505 ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // TTL is zero 2506 ptr[8] = ptr[9] = 0; // RDATA length is zero 2507 (*count)++; 2508 return(ptr + 10); 2509 } 2510 2511 mDNSexport mDNSu8 *putQuestion(DNSMessage *const msg, mDNSu8 *ptr, const mDNSu8 *const limit, const domainname *const name, mDNSu16 rrtype, mDNSu16 rrclass) 2512 { 2513 ptr = putDomainNameAsLabels(msg, ptr, limit, name); 2514 if (!ptr || ptr+4 >= limit) return(mDNSNULL); // If we're out-of-space, return mDNSNULL 2515 ptr[0] = (mDNSu8)(rrtype >> 8); 2516 ptr[1] = (mDNSu8)(rrtype & 0xFF); 2517 ptr[2] = (mDNSu8)(rrclass >> 8); 2518 ptr[3] = (mDNSu8)(rrclass & 0xFF); 2519 msg->h.numQuestions++; 2520 return(ptr+4); 2521 } 2522 2523 // for dynamic updates 2524 mDNSexport mDNSu8 *putZone(DNSMessage *const msg, mDNSu8 *ptr, mDNSu8 *limit, const domainname *zone, mDNSOpaque16 zoneClass) 2525 { 2526 ptr = putDomainNameAsLabels(msg, ptr, limit, zone); 2527 if (!ptr || ptr + 4 > limit) return mDNSNULL; // If we're out-of-space, return NULL 2528 *ptr++ = (mDNSu8)(kDNSType_SOA >> 8); 2529 *ptr++ = (mDNSu8)(kDNSType_SOA & 0xFF); 2530 *ptr++ = zoneClass.b[0]; 2531 *ptr++ = zoneClass.b[1]; 2532 msg->h.mDNS_numZones++; 2533 return ptr; 2534 } 2535 2536 // for dynamic updates 2537 mDNSexport mDNSu8 *putPrereqNameNotInUse(const domainname *const name, DNSMessage *const msg, mDNSu8 *const ptr, mDNSu8 *const end) 2538 { 2539 AuthRecord prereq; 2540 mDNS_SetupResourceRecord(&prereq, mDNSNULL, mDNSInterface_Any, kDNSQType_ANY, kStandardTTL, 0, AuthRecordAny, mDNSNULL, mDNSNULL); 2541 AssignDomainName(&prereq.namestorage, name); 2542 prereq.resrec.rrtype = kDNSQType_ANY; 2543 prereq.resrec.rrclass = kDNSClass_NONE; 2544 return putEmptyResourceRecord(msg, ptr, end, &msg->h.mDNS_numPrereqs, &prereq); 2545 } 2546 2547 // for dynamic updates 2548 mDNSexport mDNSu8 *putDeletionRecord(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr) 2549 { 2550 // deletion: specify record w/ TTL 0, class NONE 2551 const mDNSu16 origclass = rr->rrclass; 2552 rr->rrclass = kDNSClass_NONE; 2553 ptr = PutResourceRecordTTLJumbo(msg, ptr, &msg->h.mDNS_numUpdates, rr, 0); 2554 rr->rrclass = origclass; 2555 return ptr; 2556 } 2557 2558 // for dynamic updates 2559 mDNSexport mDNSu8 *putDeletionRecordWithLimit(DNSMessage *msg, mDNSu8 *ptr, ResourceRecord *rr, mDNSu8 *limit) 2560 { 2561 // deletion: specify record w/ TTL 0, class NONE 2562 const mDNSu16 origclass = rr->rrclass; 2563 rr->rrclass = kDNSClass_NONE; 2564 ptr = PutResourceRecordTTLWithLimit(msg, ptr, &msg->h.mDNS_numUpdates, rr, 0, limit); 2565 rr->rrclass = origclass; 2566 return ptr; 2567 } 2568 2569 mDNSexport mDNSu8 *putDeleteRRSetWithLimit(DNSMessage *msg, mDNSu8 *ptr, const domainname *name, mDNSu16 rrtype, mDNSu8 *limit) 2570 { 2571 mDNSu16 class = kDNSQClass_ANY; 2572 2573 ptr = putDomainNameAsLabels(msg, ptr, limit, name); 2574 if (!ptr || ptr + 10 >= limit) return mDNSNULL; // If we're out-of-space, return mDNSNULL 2575 ptr[0] = (mDNSu8)(rrtype >> 8); 2576 ptr[1] = (mDNSu8)(rrtype & 0xFF); 2577 ptr[2] = (mDNSu8)(class >> 8); 2578 ptr[3] = (mDNSu8)(class & 0xFF); 2579 ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // zero ttl 2580 ptr[8] = ptr[9] = 0; // zero rdlength/rdata 2581 2582 msg->h.mDNS_numUpdates++; 2583 return ptr + 10; 2584 } 2585 2586 // for dynamic updates 2587 mDNSexport mDNSu8 *putDeleteAllRRSets(DNSMessage *msg, mDNSu8 *ptr, const domainname *name) 2588 { 2589 const mDNSu8 *limit = msg->data + AbsoluteMaxDNSMessageData; 2590 mDNSu16 class = kDNSQClass_ANY; 2591 mDNSu16 rrtype = kDNSQType_ANY; 2592 2593 ptr = putDomainNameAsLabels(msg, ptr, limit, name); 2594 if (!ptr || ptr + 10 >= limit) return mDNSNULL; // If we're out-of-space, return mDNSNULL 2595 ptr[0] = (mDNSu8)(rrtype >> 8); 2596 ptr[1] = (mDNSu8)(rrtype & 0xFF); 2597 ptr[2] = (mDNSu8)(class >> 8); 2598 ptr[3] = (mDNSu8)(class & 0xFF); 2599 ptr[4] = ptr[5] = ptr[6] = ptr[7] = 0; // zero ttl 2600 ptr[8] = ptr[9] = 0; // zero rdlength/rdata 2601 2602 msg->h.mDNS_numUpdates++; 2603 return ptr + 10; 2604 } 2605 2606 // for dynamic updates 2607 mDNSexport mDNSu8 *putUpdateLease(DNSMessage *msg, mDNSu8 *ptr, mDNSu32 lease) 2608 { 2609 AuthRecord rr; 2610 mDNS_SetupResourceRecord(&rr, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); 2611 rr.resrec.rrclass = NormalMaxDNSMessageData; 2612 rr.resrec.rdlength = sizeof(rdataOPT); // One option in this OPT record 2613 rr.resrec.rdestimate = sizeof(rdataOPT); 2614 rr.resrec.rdata->u.opt[0].opt = kDNSOpt_Lease; 2615 rr.resrec.rdata->u.opt[0].u.updatelease = lease; 2616 ptr = PutResourceRecordTTLJumbo(msg, ptr, &msg->h.numAdditionals, &rr.resrec, 0); 2617 if (!ptr) { LogMsg("ERROR: putUpdateLease - PutResourceRecordTTL"); return mDNSNULL; } 2618 return ptr; 2619 } 2620 2621 // for dynamic updates 2622 mDNSexport mDNSu8 *putUpdateLeaseWithLimit(DNSMessage *msg, mDNSu8 *ptr, mDNSu32 lease, mDNSu8 *limit) 2623 { 2624 AuthRecord rr; 2625 mDNS_SetupResourceRecord(&rr, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); 2626 rr.resrec.rrclass = NormalMaxDNSMessageData; 2627 rr.resrec.rdlength = sizeof(rdataOPT); // One option in this OPT record 2628 rr.resrec.rdestimate = sizeof(rdataOPT); 2629 rr.resrec.rdata->u.opt[0].opt = kDNSOpt_Lease; 2630 rr.resrec.rdata->u.opt[0].u.updatelease = lease; 2631 ptr = PutResourceRecordTTLWithLimit(msg, ptr, &msg->h.numAdditionals, &rr.resrec, 0, limit); 2632 if (!ptr) { LogMsg("ERROR: putUpdateLeaseWithLimit - PutResourceRecordTTLWithLimit"); return mDNSNULL; } 2633 return ptr; 2634 } 2635 2636 mDNSexport mDNSu8 *putDNSSECOption(DNSMessage *msg, mDNSu8 *end, mDNSu8 *limit) 2637 { 2638 AuthRecord rr; 2639 mDNSu32 ttl = 0; 2640 2641 mDNS_SetupResourceRecord(&rr, mDNSNULL, mDNSInterface_Any, kDNSType_OPT, kStandardTTL, kDNSRecordTypeKnownUnique, AuthRecordAny, mDNSNULL, mDNSNULL); 2642 // It is still not clear what the right size is. We will have to fine tune this once we do 2643 // a lot of testing with DNSSEC. 2644 rr.resrec.rrclass = 4096; 2645 rr.resrec.rdlength = 0; 2646 rr.resrec.rdestimate = 0; 2647 // set the DO bit 2648 ttl |= 0x8000; 2649 end = PutResourceRecordTTLWithLimit(msg, end, &msg->h.numAdditionals, &rr.resrec, ttl, limit); 2650 if (!end) { LogMsg("ERROR: putDNSSECOption - PutResourceRecordTTLWithLimit"); return mDNSNULL; } 2651 return end; 2652 } 2653 2654 mDNSexport mDNSu8 *putHINFO(const mDNS *const m, DNSMessage *const msg, mDNSu8 *end, DomainAuthInfo *authInfo, mDNSu8 *limit) 2655 { 2656 if (authInfo && authInfo->AutoTunnel) 2657 { 2658 AuthRecord hinfo; 2659 mDNSu8 *h = hinfo.rdatastorage.u.data; 2660 mDNSu16 len = 2 + m->HIHardware.c[0] + m->HISoftware.c[0]; 2661 mDNSu8 *newptr; 2662 mDNS_SetupResourceRecord(&hinfo, mDNSNULL, mDNSInterface_Any, kDNSType_HINFO, 0, kDNSRecordTypeUnique, AuthRecordAny, mDNSNULL, mDNSNULL); 2663 AppendDomainLabel(&hinfo.namestorage, &m->hostlabel); 2664 AppendDomainName (&hinfo.namestorage, &authInfo->domain); 2665 hinfo.resrec.rroriginalttl = 0; 2666 mDNSPlatformMemCopy(h, &m->HIHardware, 1 + (mDNSu32)m->HIHardware.c[0]); 2667 h += 1 + (int)h[0]; 2668 mDNSPlatformMemCopy(h, &m->HISoftware, 1 + (mDNSu32)m->HISoftware.c[0]); 2669 hinfo.resrec.rdlength = len; 2670 hinfo.resrec.rdestimate = len; 2671 newptr = PutResourceRecordTTLWithLimit(msg, end, &msg->h.numAdditionals, &hinfo.resrec, 0, limit); 2672 return newptr; 2673 } 2674 else 2675 return end; 2676 } 2677 2678 // *************************************************************************** 2679 #if COMPILER_LIKES_PRAGMA_MARK 2680 #pragma mark - 2681 #pragma mark - DNS Message Parsing Functions 2682 #endif 2683 2684 mDNSexport mDNSu32 DomainNameHashValue(const domainname *const name) 2685 { 2686 mDNSu32 sum = 0; 2687 const mDNSu8 *c; 2688 2689 for (c = name->c; c[0] != 0 && c[1] != 0; c += 2) 2690 { 2691 sum += ((mDNSIsUpperCase(c[0]) ? c[0] + 'a' - 'A' : c[0]) << 8) | 2692 (mDNSIsUpperCase(c[1]) ? c[1] + 'a' - 'A' : c[1]); 2693 sum = (sum<<3) | (sum>>29); 2694 } 2695 if (c[0]) sum += ((mDNSIsUpperCase(c[0]) ? c[0] + 'a' - 'A' : c[0]) << 8); 2696 return(sum); 2697 } 2698 2699 mDNSexport void SetNewRData(ResourceRecord *const rr, RData *NewRData, mDNSu16 rdlength) 2700 { 2701 domainname *target; 2702 if (NewRData) 2703 { 2704 rr->rdata = NewRData; 2705 rr->rdlength = rdlength; 2706 } 2707 // Must not try to get target pointer until after updating rr->rdata 2708 target = GetRRDomainNameTarget(rr); 2709 rr->rdlength = GetRDLength(rr, mDNSfalse); 2710 rr->rdestimate = GetRDLength(rr, mDNStrue); 2711 rr->rdatahash = target ? DomainNameHashValue(target) : RDataHashValue(rr); 2712 } 2713 2714 mDNSexport const mDNSu8 *skipDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end) 2715 { 2716 mDNSu16 total = 0; 2717 2718 if (ptr < (mDNSu8*)msg || ptr >= end) 2719 { debugf("skipDomainName: Illegal ptr not within packet boundaries"); return(mDNSNULL); } 2720 2721 while (1) // Read sequence of labels 2722 { 2723 const mDNSu8 len = *ptr++; // Read length of this label 2724 if (len == 0) return(ptr); // If length is zero, that means this name is complete 2725 switch (len & 0xC0) 2726 { 2727 case 0x00: if (ptr + len >= end) // Remember: expect at least one more byte for the root label 2728 { debugf("skipDomainName: Malformed domain name (overruns packet end)"); return(mDNSNULL); } 2729 if (total + 1 + len >= MAX_DOMAIN_NAME) // Remember: expect at least one more byte for the root label 2730 { debugf("skipDomainName: Malformed domain name (more than 256 characters)"); return(mDNSNULL); } 2731 ptr += len; 2732 total += 1 + len; 2733 break; 2734 2735 case 0x40: debugf("skipDomainName: Extended EDNS0 label types 0x%X not supported", len); return(mDNSNULL); 2736 case 0x80: debugf("skipDomainName: Illegal label length 0x%X", len); return(mDNSNULL); 2737 case 0xC0: return(ptr+1); 2738 } 2739 } 2740 } 2741 2742 // Routine to fetch an FQDN from the DNS message, following compression pointers if necessary. 2743 mDNSexport const mDNSu8 *getDomainName(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end, 2744 domainname *const name) 2745 { 2746 const mDNSu8 *nextbyte = mDNSNULL; // Record where we got to before we started following pointers 2747 mDNSu8 *np = name->c; // Name pointer 2748 const mDNSu8 *const limit = np + MAX_DOMAIN_NAME; // Limit so we don't overrun buffer 2749 2750 if (ptr < (mDNSu8*)msg || ptr >= end) 2751 { debugf("getDomainName: Illegal ptr not within packet boundaries"); return(mDNSNULL); } 2752 2753 *np = 0; // Tentatively place the root label here (may be overwritten if we have more labels) 2754 2755 while (1) // Read sequence of labels 2756 { 2757 const mDNSu8 len = *ptr++; // Read length of this label 2758 if (len == 0) break; // If length is zero, that means this name is complete 2759 switch (len & 0xC0) 2760 { 2761 int i; 2762 mDNSu16 offset; 2763 2764 case 0x00: if (ptr + len >= end) // Remember: expect at least one more byte for the root label 2765 { debugf("getDomainName: Malformed domain name (overruns packet end)"); return(mDNSNULL); } 2766 if (np + 1 + len >= limit) // Remember: expect at least one more byte for the root label 2767 { debugf("getDomainName: Malformed domain name (more than 256 characters)"); return(mDNSNULL); } 2768 *np++ = len; 2769 for (i=0; i<len; i++) *np++ = *ptr++; 2770 *np = 0; // Tentatively place the root label here (may be overwritten if we have more labels) 2771 break; 2772 2773 case 0x40: debugf("getDomainName: Extended EDNS0 label types 0x%X not supported in name %##s", len, name->c); 2774 return(mDNSNULL); 2775 2776 case 0x80: debugf("getDomainName: Illegal label length 0x%X in domain name %##s", len, name->c); return(mDNSNULL); 2777 2778 case 0xC0: offset = (mDNSu16)((((mDNSu16)(len & 0x3F)) << 8) | *ptr++); 2779 if (!nextbyte) nextbyte = ptr; // Record where we got to before we started following pointers 2780 ptr = (mDNSu8 *)msg + offset; 2781 if (ptr < (mDNSu8*)msg || ptr >= end) 2782 { debugf("getDomainName: Illegal compression pointer not within packet boundaries"); return(mDNSNULL); } 2783 if (*ptr & 0xC0) 2784 { debugf("getDomainName: Compression pointer must point to real label"); return(mDNSNULL); } 2785 break; 2786 } 2787 } 2788 2789 if (nextbyte) return(nextbyte); 2790 else return(ptr); 2791 } 2792 2793 mDNSexport const mDNSu8 *skipResourceRecord(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end) 2794 { 2795 mDNSu16 pktrdlength; 2796 2797 ptr = skipDomainName(msg, ptr, end); 2798 if (!ptr) { debugf("skipResourceRecord: Malformed RR name"); return(mDNSNULL); } 2799 2800 if (ptr + 10 > end) { debugf("skipResourceRecord: Malformed RR -- no type/class/ttl/len!"); return(mDNSNULL); } 2801 pktrdlength = (mDNSu16)((mDNSu16)ptr[8] << 8 | ptr[9]); 2802 ptr += 10; 2803 if (ptr + pktrdlength > end) { debugf("skipResourceRecord: RDATA exceeds end of packet"); return(mDNSNULL); } 2804 2805 return(ptr + pktrdlength); 2806 } 2807 2808 // Sanity check whether the NSEC/NSEC3 bitmap is good 2809 mDNSlocal mDNSu8 *SanityCheckBitMap(const mDNSu8 *bmap, const mDNSu8 *end, int len) 2810 { 2811 int win, wlen; 2812 2813 while (bmap < end) 2814 { 2815 if (len < 3) 2816 { 2817 LogInfo("SanityCheckBitMap: invalid length %d", len); 2818 return mDNSNULL; 2819 } 2820 2821 win = *bmap++; 2822 wlen = *bmap++; 2823 len -= 2; 2824 if (len < wlen || wlen < 1 || wlen > 32) 2825 { 2826 LogInfo("SanityCheckBitMap: invalid window length %d", wlen); 2827 return mDNSNULL; 2828 } 2829 if (win < 0 || win >= 256) 2830 { 2831 LogInfo("SanityCheckBitMap: invalid window %d", win); 2832 return mDNSNULL; 2833 } 2834 2835 bmap += wlen; 2836 len -= wlen; 2837 } 2838 return (mDNSu8 *)bmap; 2839 } 2840 2841 // This function is called with "msg" when we receive a DNS message and needs to parse a single resource record 2842 // pointed to by "ptr". Some resource records like SOA, SRV are converted to host order and also expanded 2843 // (domainnames are expanded to 255 bytes) when stored in memory. 2844 // 2845 // This function can also be called with "NULL" msg to parse a single resource record pointed to by ptr. 2846 // The caller can do this only if the names in the resource records are compressed and validity of the 2847 // resource record has already been done before. DNSSEC currently uses it this way. 2848 mDNSexport mDNSBool SetRData(const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *end, 2849 LargeCacheRecord *const largecr, mDNSu16 rdlength) 2850 { 2851 CacheRecord *const rr = &largecr->r; 2852 RDataBody2 *const rdb = (RDataBody2 *)rr->smallrdatastorage.data; 2853 2854 switch (rr->resrec.rrtype) 2855 { 2856 case kDNSType_A: 2857 if (rdlength != sizeof(mDNSv4Addr)) 2858 goto fail; 2859 rdb->ipv4.b[0] = ptr[0]; 2860 rdb->ipv4.b[1] = ptr[1]; 2861 rdb->ipv4.b[2] = ptr[2]; 2862 rdb->ipv4.b[3] = ptr[3]; 2863 break; 2864 2865 case kDNSType_NS: 2866 case kDNSType_MD: 2867 case kDNSType_MF: 2868 case kDNSType_CNAME: 2869 case kDNSType_MB: 2870 case kDNSType_MG: 2871 case kDNSType_MR: 2872 case kDNSType_PTR: 2873 case kDNSType_NSAP_PTR: 2874 case kDNSType_DNAME: 2875 if (msg) 2876 { 2877 ptr = getDomainName(msg, ptr, end, &rdb->name); 2878 } 2879 else 2880 { 2881 AssignDomainName(&rdb->name, (domainname *)ptr); 2882 ptr += DomainNameLength(&rdb->name); 2883 } 2884 if (ptr != end) 2885 { 2886 debugf("SetRData: Malformed CNAME/PTR RDATA name"); 2887 goto fail; 2888 } 2889 break; 2890 2891 case kDNSType_SOA: 2892 if (msg) 2893 { 2894 ptr = getDomainName(msg, ptr, end, &rdb->soa.mname); 2895 } 2896 else 2897 { 2898 AssignDomainName(&rdb->soa.mname, (domainname *)ptr); 2899 ptr += DomainNameLength(&rdb->soa.mname); 2900 } 2901 if (!ptr) 2902 { 2903 debugf("SetRData: Malformed SOA RDATA mname"); 2904 goto fail; 2905 } 2906 if (msg) 2907 { 2908 ptr = getDomainName(msg, ptr, end, &rdb->soa.rname); 2909 } 2910 else 2911 { 2912 AssignDomainName(&rdb->soa.rname, (domainname *)ptr); 2913 ptr += DomainNameLength(&rdb->soa.rname); 2914 } 2915 if (!ptr) 2916 { 2917 debugf("SetRData: Malformed SOA RDATA rname"); 2918 goto fail; 2919 } 2920 if (ptr + 0x14 != end) 2921 { 2922 debugf("SetRData: Malformed SOA RDATA"); 2923 goto fail; 2924 } 2925 rdb->soa.serial = (mDNSs32) ((mDNSs32)ptr[0x00] << 24 | (mDNSs32)ptr[0x01] << 16 | (mDNSs32)ptr[0x02] << 8 | ptr[0x03]); 2926 rdb->soa.refresh = (mDNSu32) ((mDNSu32)ptr[0x04] << 24 | (mDNSu32)ptr[0x05] << 16 | (mDNSu32)ptr[0x06] << 8 | ptr[0x07]); 2927 rdb->soa.retry = (mDNSu32) ((mDNSu32)ptr[0x08] << 24 | (mDNSu32)ptr[0x09] << 16 | (mDNSu32)ptr[0x0A] << 8 | ptr[0x0B]); 2928 rdb->soa.expire = (mDNSu32) ((mDNSu32)ptr[0x0C] << 24 | (mDNSu32)ptr[0x0D] << 16 | (mDNSu32)ptr[0x0E] << 8 | ptr[0x0F]); 2929 rdb->soa.min = (mDNSu32) ((mDNSu32)ptr[0x10] << 24 | (mDNSu32)ptr[0x11] << 16 | (mDNSu32)ptr[0x12] << 8 | ptr[0x13]); 2930 break; 2931 2932 case kDNSType_NULL: 2933 case kDNSType_HINFO: 2934 case kDNSType_TXT: 2935 case kDNSType_X25: 2936 case kDNSType_ISDN: 2937 case kDNSType_LOC: 2938 case kDNSType_DHCID: 2939 rr->resrec.rdlength = rdlength; 2940 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 2941 break; 2942 2943 case kDNSType_MX: 2944 case kDNSType_AFSDB: 2945 case kDNSType_RT: 2946 case kDNSType_KX: 2947 // Preference + domainname 2948 if (rdlength < 3) 2949 goto fail; 2950 rdb->mx.preference = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); 2951 ptr += 2; 2952 if (msg) 2953 { 2954 ptr = getDomainName(msg, ptr, end, &rdb->mx.exchange); 2955 } 2956 else 2957 { 2958 AssignDomainName(&rdb->mx.exchange, (domainname *)ptr); 2959 ptr += DomainNameLength(&rdb->mx.exchange); 2960 } 2961 if (ptr != end) 2962 { 2963 debugf("SetRData: Malformed MX name"); 2964 goto fail; 2965 } 2966 break; 2967 2968 case kDNSType_MINFO: 2969 case kDNSType_RP: 2970 // Domainname + domainname 2971 if (msg) 2972 { 2973 ptr = getDomainName(msg, ptr, end, &rdb->rp.mbox); 2974 } 2975 else 2976 { 2977 AssignDomainName(&rdb->rp.mbox, (domainname *)ptr); 2978 ptr += DomainNameLength(&rdb->rp.mbox); 2979 } 2980 if (!ptr) 2981 { 2982 debugf("SetRData: Malformed RP mbox"); 2983 goto fail; 2984 } 2985 if (msg) 2986 { 2987 ptr = getDomainName(msg, ptr, end, &rdb->rp.txt); 2988 } 2989 else 2990 { 2991 AssignDomainName(&rdb->rp.txt, (domainname *)ptr); 2992 ptr += DomainNameLength(&rdb->rp.txt); 2993 } 2994 if (ptr != end) 2995 { 2996 debugf("SetRData: Malformed RP txt"); 2997 goto fail; 2998 } 2999 break; 3000 3001 case kDNSType_PX: 3002 // Preference + domainname + domainname 3003 if (rdlength < 4) 3004 goto fail; 3005 rdb->px.preference = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); 3006 ptr += 2; 3007 if (msg) 3008 { 3009 ptr = getDomainName(msg, ptr, end, &rdb->px.map822); 3010 } 3011 else 3012 { 3013 AssignDomainName(&rdb->px.map822, (domainname *)ptr); 3014 ptr += DomainNameLength(&rdb->px.map822); 3015 } 3016 if (!ptr) 3017 { 3018 debugf("SetRData: Malformed PX map822"); 3019 goto fail; 3020 } 3021 if (msg) 3022 { 3023 ptr = getDomainName(msg, ptr, end, &rdb->px.mapx400); 3024 } 3025 else 3026 { 3027 AssignDomainName(&rdb->px.mapx400, (domainname *)ptr); 3028 ptr += DomainNameLength(&rdb->px.mapx400); 3029 } 3030 if (ptr != end) 3031 { 3032 debugf("SetRData: Malformed PX mapx400"); 3033 goto fail; 3034 } 3035 break; 3036 3037 case kDNSType_AAAA: 3038 if (rdlength != sizeof(mDNSv6Addr)) 3039 goto fail; 3040 mDNSPlatformMemCopy(&rdb->ipv6, ptr, sizeof(rdb->ipv6)); 3041 break; 3042 3043 case kDNSType_SRV: 3044 // Priority + weight + port + domainname 3045 if (rdlength < 7) 3046 goto fail; 3047 rdb->srv.priority = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); 3048 rdb->srv.weight = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); 3049 rdb->srv.port.b[0] = ptr[4]; 3050 rdb->srv.port.b[1] = ptr[5]; 3051 ptr += 6; 3052 if (msg) 3053 { 3054 ptr = getDomainName(msg, ptr, end, &rdb->srv.target); 3055 } 3056 else 3057 { 3058 AssignDomainName(&rdb->srv.target, (domainname *)ptr); 3059 ptr += DomainNameLength(&rdb->srv.target); 3060 } 3061 if (ptr != end) 3062 { 3063 debugf("SetRData: Malformed SRV RDATA name"); 3064 goto fail; 3065 } 3066 break; 3067 3068 case kDNSType_NAPTR: 3069 { 3070 int savelen, len; 3071 domainname name; 3072 const mDNSu8 *orig = ptr; 3073 3074 // Make sure the data is parseable and within the limits. DNSSEC code looks at 3075 // the domain name in the end for a valid domainname. 3076 // 3077 // Fixed length: Order, preference (4 bytes) 3078 // Variable length: flags, service, regexp, domainname 3079 3080 if (rdlength < 8) 3081 goto fail; 3082 // Order, preference. 3083 ptr += 4; 3084 // Parse flags, Service and Regexp 3085 // length in the first byte does not include the length byte itself 3086 len = *ptr + 1; 3087 ptr += len; 3088 if (ptr >= end) 3089 { 3090 LogInfo("SetRData: Malformed NAPTR flags"); 3091 goto fail; 3092 } 3093 3094 // Service 3095 len = *ptr + 1; 3096 ptr += len; 3097 if (ptr >= end) 3098 { 3099 LogInfo("SetRData: Malformed NAPTR service"); 3100 goto fail; 3101 } 3102 3103 // Regexp 3104 len = *ptr + 1; 3105 ptr += len; 3106 if (ptr >= end) 3107 { 3108 LogInfo("SetRData: Malformed NAPTR regexp"); 3109 goto fail; 3110 } 3111 3112 savelen = ptr - orig; 3113 3114 // RFC 2915 states that name compression is not allowed for this field. But RFC 3597 3115 // states that for NAPTR we should decompress. We make sure that we store the full 3116 // name rather than the compressed name 3117 if (msg) 3118 { 3119 ptr = getDomainName(msg, ptr, end, &name); 3120 } 3121 else 3122 { 3123 AssignDomainName(&name, (domainname *)ptr); 3124 ptr += DomainNameLength(&name); 3125 } 3126 if (ptr != end) 3127 { 3128 LogInfo("SetRData: Malformed NAPTR RDATA name"); 3129 goto fail; 3130 } 3131 3132 rr->resrec.rdlength = savelen + DomainNameLength(&name); 3133 // The uncompressed size should not exceed the limits 3134 if (rr->resrec.rdlength > MaximumRDSize) 3135 { 3136 LogInfo("SetRData: Malformed NAPTR rdlength %d, rr->resrec.rdlength %d, " 3137 "bmaplen %d, name %##s", rdlength, rr->resrec.rdlength, name.c); 3138 goto fail; 3139 } 3140 mDNSPlatformMemCopy(rdb->data, orig, savelen); 3141 AssignDomainName((domainname *)(rdb->data + savelen), &name); 3142 break; 3143 } 3144 case kDNSType_OPT: { 3145 mDNSu8 *dataend = rr->resrec.rdata->u.data; 3146 rdataOPT *opt = rr->resrec.rdata->u.opt; 3147 rr->resrec.rdlength = 0; 3148 while (ptr < end && (mDNSu8 *)(opt+1) < &dataend[MaximumRDSize]) 3149 { 3150 const rdataOPT *const currentopt = opt; 3151 if (ptr + 4 > end) { LogInfo("SetRData: OPT RDATA ptr + 4 > end"); goto fail; } 3152 opt->opt = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); 3153 opt->optlen = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); 3154 ptr += 4; 3155 if (ptr + opt->optlen > end) { LogInfo("SetRData: ptr + opt->optlen > end"); goto fail; } 3156 switch (opt->opt) 3157 { 3158 case kDNSOpt_LLQ: 3159 if (opt->optlen == DNSOpt_LLQData_Space - 4) 3160 { 3161 opt->u.llq.vers = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); 3162 opt->u.llq.llqOp = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); 3163 opt->u.llq.err = (mDNSu16)((mDNSu16)ptr[4] << 8 | ptr[5]); 3164 mDNSPlatformMemCopy(opt->u.llq.id.b, ptr+6, 8); 3165 opt->u.llq.llqlease = (mDNSu32) ((mDNSu32)ptr[14] << 24 | (mDNSu32)ptr[15] << 16 | (mDNSu32)ptr[16] << 8 | ptr[17]); 3166 if (opt->u.llq.llqlease > 0x70000000UL / mDNSPlatformOneSecond) 3167 opt->u.llq.llqlease = 0x70000000UL / mDNSPlatformOneSecond; 3168 opt++; 3169 } 3170 break; 3171 case kDNSOpt_Lease: 3172 if (opt->optlen == DNSOpt_LeaseData_Space - 4) 3173 { 3174 opt->u.updatelease = (mDNSu32) ((mDNSu32)ptr[0] << 24 | (mDNSu32)ptr[1] << 16 | (mDNSu32)ptr[2] << 8 | ptr[3]); 3175 if (opt->u.updatelease > 0x70000000UL / mDNSPlatformOneSecond) 3176 opt->u.updatelease = 0x70000000UL / mDNSPlatformOneSecond; 3177 opt++; 3178 } 3179 break; 3180 case kDNSOpt_Owner: 3181 if (ValidOwnerLength(opt->optlen)) 3182 { 3183 opt->u.owner.vers = ptr[0]; 3184 opt->u.owner.seq = ptr[1]; 3185 mDNSPlatformMemCopy(opt->u.owner.HMAC.b, ptr+2, 6); // 6-byte MAC address 3186 mDNSPlatformMemCopy(opt->u.owner.IMAC.b, ptr+2, 6); // 6-byte MAC address 3187 opt->u.owner.password = zeroEthAddr; 3188 if (opt->optlen >= DNSOpt_OwnerData_ID_Wake_Space-4) 3189 { 3190 mDNSPlatformMemCopy(opt->u.owner.IMAC.b, ptr+8, 6); // 6-byte MAC address 3191 // This mDNSPlatformMemCopy is safe because the ValidOwnerLength(opt->optlen) check above 3192 // ensures that opt->optlen is no more than DNSOpt_OwnerData_ID_Wake_PW6_Space - 4 3193 if (opt->optlen > DNSOpt_OwnerData_ID_Wake_Space-4) 3194 mDNSPlatformMemCopy(opt->u.owner.password.b, ptr+14, opt->optlen - (DNSOpt_OwnerData_ID_Wake_Space-4)); 3195 } 3196 opt++; 3197 } 3198 break; 3199 case kDNSOpt_Trace: 3200 if (opt->optlen == DNSOpt_TraceData_Space - 4) 3201 { 3202 opt->u.tracer.platf = ptr[0]; 3203 opt->u.tracer.mDNSv = (mDNSu32) ((mDNSu32)ptr[1] << 24 | (mDNSu32)ptr[2] << 16 | (mDNSu32)ptr[3] << 8 | ptr[4]); 3204 opt++; 3205 } 3206 else 3207 { 3208 opt->u.tracer.platf = 0xFF; 3209 opt->u.tracer.mDNSv = 0xFFFFFFFF; 3210 opt++; 3211 } 3212 break; 3213 } 3214 ptr += currentopt->optlen; 3215 } 3216 rr->resrec.rdlength = (mDNSu16)((mDNSu8*)opt - rr->resrec.rdata->u.data); 3217 if (ptr != end) { LogInfo("SetRData: Malformed OptRdata"); goto fail; } 3218 break; 3219 } 3220 3221 case kDNSType_NSEC: { 3222 domainname name; 3223 int len = rdlength; 3224 int bmaplen, dlen; 3225 const mDNSu8 *orig = ptr; 3226 const mDNSu8 *bmap; 3227 3228 if (msg) 3229 { 3230 ptr = getDomainName(msg, ptr, end, &name); 3231 } 3232 else 3233 { 3234 AssignDomainName(&name, (domainname *)ptr); 3235 ptr += DomainNameLength(&name); 3236 } 3237 if (!ptr) 3238 { 3239 LogInfo("SetRData: Malformed NSEC nextname"); 3240 goto fail; 3241 } 3242 3243 dlen = DomainNameLength(&name); 3244 3245 // Multicast NSECs use name compression for this field unlike the unicast case which 3246 // does not use compression. And multicast case always succeeds in compression. So, 3247 // the rdlength includes only the compressed space in that case. So, can't 3248 // use the DomainNameLength of name to reduce the length here. 3249 len -= (ptr - orig); 3250 bmaplen = len; // Save the length of the bitmap 3251 bmap = ptr; 3252 ptr = SanityCheckBitMap(bmap, end, len); 3253 if (!ptr) 3254 goto fail; 3255 if (ptr != end) 3256 { 3257 LogInfo("SetRData: Malformed NSEC length not right"); 3258 goto fail; 3259 } 3260 3261 // Initialize the right length here. When we call SetNewRData below which in turn calls 3262 // GetRDLength and for NSEC case, it assumes that rdlength is intitialized 3263 rr->resrec.rdlength = DomainNameLength(&name) + bmaplen; 3264 3265 // Do we have space after the name expansion ? 3266 if (rr->resrec.rdlength > MaximumRDSize) 3267 { 3268 LogInfo("SetRData: Malformed NSEC rdlength %d, rr->resrec.rdlength %d, " 3269 "bmaplen %d, name %##s", rdlength, rr->resrec.rdlength, name.c); 3270 goto fail; 3271 } 3272 AssignDomainName((domainname *)rdb->data, &name); 3273 mDNSPlatformMemCopy(rdb->data + dlen, bmap, bmaplen); 3274 break; 3275 } 3276 case kDNSType_NSEC3: 3277 { 3278 rdataNSEC3 *nsec3 = (rdataNSEC3 *)ptr; 3279 mDNSu8 *p = (mDNSu8 *)&nsec3->salt; 3280 int hashLength, bitmaplen; 3281 3282 if (rdlength < NSEC3_FIXED_SIZE + 1) 3283 { 3284 LogInfo("SetRData: NSEC3 too small length %d", rdlength); 3285 goto fail; 3286 } 3287 if (nsec3->alg != SHA1_DIGEST_TYPE) 3288 { 3289 LogInfo("SetRData: nsec3 alg %d not supported", nsec3->alg); 3290 goto fail; 3291 } 3292 if (swap16(nsec3->iterations) > NSEC3_MAX_ITERATIONS) 3293 { 3294 LogInfo("SetRData: nsec3 iteration count %d too big", swap16(nsec3->iterations)); 3295 goto fail; 3296 } 3297 p += nsec3->saltLength; 3298 // There should at least be one byte beyond saltLength 3299 if (p >= end) 3300 { 3301 LogInfo("SetRData: nsec3 too small, at saltlength %d, p %p, end %p", nsec3->saltLength, p, end); 3302 goto fail; 3303 } 3304 // p is pointing at hashLength 3305 hashLength = (int)*p++; 3306 if (!hashLength) 3307 { 3308 LogInfo("SetRData: hashLength zero"); 3309 goto fail; 3310 } 3311 p += hashLength; 3312 if (p > end) 3313 { 3314 LogInfo("SetRData: nsec3 too small, at hashLength %d, p %p, end %p", hashLength, p, end); 3315 goto fail; 3316 } 3317 3318 bitmaplen = rdlength - (int)(p - ptr); 3319 p = SanityCheckBitMap(p, end, bitmaplen); 3320 if (!p) 3321 goto fail; 3322 rr->resrec.rdlength = rdlength; 3323 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 3324 break; 3325 } 3326 case kDNSType_TKEY: 3327 case kDNSType_TSIG: 3328 { 3329 domainname name; 3330 int dlen, rlen; 3331 3332 // The name should not be compressed. But we take the conservative approach 3333 // and uncompress the name before we store it. 3334 if (msg) 3335 { 3336 ptr = getDomainName(msg, ptr, end, &name); 3337 } 3338 else 3339 { 3340 AssignDomainName(&name, (domainname *)ptr); 3341 ptr += DomainNameLength(&name); 3342 } 3343 if (!ptr) 3344 { 3345 LogInfo("SetRData: Malformed name for TSIG/TKEY type %d", rr->resrec.rrtype); 3346 goto fail; 3347 } 3348 dlen = DomainNameLength(&name); 3349 rlen = end - ptr; 3350 rr->resrec.rdlength = dlen + rlen; 3351 AssignDomainName((domainname *)rdb->data, &name); 3352 mDNSPlatformMemCopy(rdb->data + dlen, ptr, rlen); 3353 break; 3354 } 3355 case kDNSType_RRSIG: 3356 { 3357 const mDNSu8 *sig = ptr + RRSIG_FIXED_SIZE; 3358 const mDNSu8 *orig = sig; 3359 domainname name; 3360 if (rdlength < RRSIG_FIXED_SIZE + 1) 3361 { 3362 LogInfo("SetRData: RRSIG too small length %d", rdlength); 3363 goto fail; 3364 } 3365 if (msg) 3366 { 3367 sig = getDomainName(msg, sig, end, &name); 3368 } 3369 else 3370 { 3371 AssignDomainName(&name, (domainname *)sig); 3372 sig += DomainNameLength(&name); 3373 } 3374 if (!sig) 3375 { 3376 LogInfo("SetRData: Malformed RRSIG record"); 3377 goto fail; 3378 } 3379 3380 if ((sig - orig) != DomainNameLength(&name)) 3381 { 3382 LogInfo("SetRData: Malformed RRSIG record, signer name compression"); 3383 goto fail; 3384 } 3385 // Just ensure that we have at least one byte of the signature 3386 if (sig + 1 >= end) 3387 { 3388 LogInfo("SetRData: Not enough bytes for signature type %d", rr->resrec.rrtype); 3389 goto fail; 3390 } 3391 rr->resrec.rdlength = rdlength; 3392 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 3393 break; 3394 } 3395 case kDNSType_DNSKEY: 3396 { 3397 if (rdlength < DNSKEY_FIXED_SIZE + 1) 3398 { 3399 LogInfo("SetRData: DNSKEY too small length %d", rdlength); 3400 goto fail; 3401 } 3402 rr->resrec.rdlength = rdlength; 3403 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 3404 break; 3405 } 3406 case kDNSType_DS: 3407 { 3408 if (rdlength < DS_FIXED_SIZE + 1) 3409 { 3410 LogInfo("SetRData: DS too small length %d", rdlength); 3411 goto fail; 3412 } 3413 rr->resrec.rdlength = rdlength; 3414 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 3415 break; 3416 } 3417 default: 3418 debugf("SetRData: Warning! Reading resource type %d (%s) as opaque data", 3419 rr->resrec.rrtype, DNSTypeName(rr->resrec.rrtype)); 3420 // Note: Just because we don't understand the record type, that doesn't 3421 // mean we fail. The DNS protocol specifies rdlength, so we can 3422 // safely skip over unknown records and ignore them. 3423 // We also grab a binary copy of the rdata anyway, since the caller 3424 // might know how to interpret it even if we don't. 3425 rr->resrec.rdlength = rdlength; 3426 mDNSPlatformMemCopy(rdb->data, ptr, rdlength); 3427 break; 3428 } 3429 return mDNStrue; 3430 fail: 3431 return mDNSfalse; 3432 } 3433 3434 mDNSexport const mDNSu8 *GetLargeResourceRecord(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *ptr, 3435 const mDNSu8 *end, const mDNSInterfaceID InterfaceID, mDNSu8 RecordType, LargeCacheRecord *const largecr) 3436 { 3437 CacheRecord *const rr = &largecr->r; 3438 mDNSu16 pktrdlength; 3439 3440 if (largecr == &m->rec && m->rec.r.resrec.RecordType) 3441 LogFatalError("GetLargeResourceRecord: m->rec appears to be already in use for %s", CRDisplayString(m, &m->rec.r)); 3442 3443 rr->next = mDNSNULL; 3444 rr->resrec.name = &largecr->namestorage; 3445 3446 rr->NextInKAList = mDNSNULL; 3447 rr->TimeRcvd = m ? m->timenow : 0; 3448 rr->DelayDelivery = 0; 3449 rr->NextRequiredQuery = m ? m->timenow : 0; // Will be updated to the real value when we call SetNextCacheCheckTimeForRecord() 3450 rr->LastUsed = m ? m->timenow : 0; 3451 rr->CRActiveQuestion = mDNSNULL; 3452 rr->UnansweredQueries = 0; 3453 rr->LastUnansweredTime= 0; 3454 #if ENABLE_MULTI_PACKET_QUERY_SNOOPING 3455 rr->MPUnansweredQ = 0; 3456 rr->MPLastUnansweredQT= 0; 3457 rr->MPUnansweredKA = 0; 3458 rr->MPExpectingKA = mDNSfalse; 3459 #endif 3460 rr->NextInCFList = mDNSNULL; 3461 3462 rr->resrec.InterfaceID = InterfaceID; 3463 rr->resrec.rDNSServer = mDNSNULL; 3464 3465 ptr = getDomainName(msg, ptr, end, &largecr->namestorage); // Will bail out correctly if ptr is NULL 3466 if (!ptr) { debugf("GetLargeResourceRecord: Malformed RR name"); return(mDNSNULL); } 3467 rr->resrec.namehash = DomainNameHashValue(rr->resrec.name); 3468 3469 if (ptr + 10 > end) { debugf("GetLargeResourceRecord: Malformed RR -- no type/class/ttl/len!"); return(mDNSNULL); } 3470 3471 rr->resrec.rrtype = (mDNSu16) ((mDNSu16)ptr[0] << 8 | ptr[1]); 3472 rr->resrec.rrclass = (mDNSu16)(((mDNSu16)ptr[2] << 8 | ptr[3]) & kDNSClass_Mask); 3473 rr->resrec.rroriginalttl = (mDNSu32) ((mDNSu32)ptr[4] << 24 | (mDNSu32)ptr[5] << 16 | (mDNSu32)ptr[6] << 8 | ptr[7]); 3474 if (rr->resrec.rroriginalttl > 0x70000000UL / mDNSPlatformOneSecond && (mDNSs32)rr->resrec.rroriginalttl != -1) 3475 rr->resrec.rroriginalttl = 0x70000000UL / mDNSPlatformOneSecond; 3476 // Note: We don't have to adjust m->NextCacheCheck here -- this is just getting a record into memory for 3477 // us to look at. If we decide to copy it into the cache, then we'll update m->NextCacheCheck accordingly. 3478 pktrdlength = (mDNSu16)((mDNSu16)ptr[8] << 8 | ptr[9]); 3479 3480 // If mDNS record has cache-flush bit set, we mark it unique 3481 // For uDNS records, all are implicitly deemed unique (a single DNS server is always 3482 // authoritative for the entire RRSet), unless this is a truncated response 3483 if (ptr[2] & (kDNSClass_UniqueRRSet >> 8) || (!InterfaceID && !(msg->h.flags.b[0] & kDNSFlag0_TC))) 3484 RecordType |= kDNSRecordTypePacketUniqueMask; 3485 ptr += 10; 3486 if (ptr + pktrdlength > end) { debugf("GetLargeResourceRecord: RDATA exceeds end of packet"); return(mDNSNULL); } 3487 end = ptr + pktrdlength; // Adjust end to indicate the end of the rdata for this resource record 3488 3489 rr->resrec.rdata = (RData*)&rr->smallrdatastorage; 3490 rr->resrec.rdata->MaxRDLength = MaximumRDSize; 3491 3492 if (pktrdlength > MaximumRDSize) 3493 { 3494 LogInfo("GetLargeResourceRecord: %s rdata size (%d) exceeds storage (%d)", 3495 DNSTypeName(rr->resrec.rrtype), pktrdlength, rr->resrec.rdata->MaxRDLength); 3496 goto fail; 3497 } 3498 3499 if (!RecordType) LogMsg("GetLargeResourceRecord: No RecordType for %##s", rr->resrec.name->c); 3500 3501 // IMPORTANT: Any record type we understand and unpack into a structure containing domainnames needs to have corresponding 3502 // cases in SameRDataBody() and RDataHashValue() to do a semantic comparison (or checksum) of the structure instead of a blind 3503 // bitwise memory compare (or sum). This is because a domainname is a fixed size structure holding variable-length data. 3504 // Any bytes past the logical end of the name are undefined, and a blind bitwise memory compare may indicate that 3505 // two domainnames are different when semantically they are the same name and it's only the unused bytes that differ. 3506 if (rr->resrec.rrclass == kDNSQClass_ANY && pktrdlength == 0) // Used in update packets to mean "Delete An RRset" (RFC 2136) 3507 rr->resrec.rdlength = 0; 3508 else if (!SetRData(msg, ptr, end, largecr, pktrdlength)) 3509 goto fail; 3510 3511 SetNewRData(&rr->resrec, mDNSNULL, 0); // Sets rdlength, rdestimate, rdatahash for us 3512 3513 // Success! Now fill in RecordType to show this record contains valid data 3514 rr->resrec.RecordType = RecordType; 3515 return(end); 3516 3517 fail: 3518 // If we were unable to parse the rdata in this record, we indicate that by 3519 // returing a 'kDNSRecordTypePacketNegative' record with rdlength set to zero 3520 rr->resrec.RecordType = kDNSRecordTypePacketNegative; 3521 rr->resrec.rdlength = 0; 3522 rr->resrec.rdestimate = 0; 3523 rr->resrec.rdatahash = 0; 3524 return(end); 3525 } 3526 3527 mDNSexport const mDNSu8 *skipQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end) 3528 { 3529 ptr = skipDomainName(msg, ptr, end); 3530 if (!ptr) { debugf("skipQuestion: Malformed domain name in DNS question section"); return(mDNSNULL); } 3531 if (ptr+4 > end) { debugf("skipQuestion: Malformed DNS question section -- no query type and class!"); return(mDNSNULL); } 3532 return(ptr+4); 3533 } 3534 3535 mDNSexport const mDNSu8 *getQuestion(const DNSMessage *msg, const mDNSu8 *ptr, const mDNSu8 *end, const mDNSInterfaceID InterfaceID, 3536 DNSQuestion *question) 3537 { 3538 mDNSPlatformMemZero(question, sizeof(*question)); 3539 question->InterfaceID = InterfaceID; 3540 if (!InterfaceID) question->TargetQID = onesID; // In DNSQuestions we use TargetQID as the indicator of whether it's unicast or multicast 3541 ptr = getDomainName(msg, ptr, end, &question->qname); 3542 if (!ptr) { debugf("Malformed domain name in DNS question section"); return(mDNSNULL); } 3543 if (ptr+4 > end) { debugf("Malformed DNS question section -- no query type and class!"); return(mDNSNULL); } 3544 3545 question->qnamehash = DomainNameHashValue(&question->qname); 3546 question->qtype = (mDNSu16)((mDNSu16)ptr[0] << 8 | ptr[1]); // Get type 3547 question->qclass = (mDNSu16)((mDNSu16)ptr[2] << 8 | ptr[3]); // and class 3548 return(ptr+4); 3549 } 3550 3551 mDNSexport const mDNSu8 *LocateAnswers(const DNSMessage *const msg, const mDNSu8 *const end) 3552 { 3553 int i; 3554 const mDNSu8 *ptr = msg->data; 3555 for (i = 0; i < msg->h.numQuestions && ptr; i++) ptr = skipQuestion(msg, ptr, end); 3556 return(ptr); 3557 } 3558 3559 mDNSexport const mDNSu8 *LocateAuthorities(const DNSMessage *const msg, const mDNSu8 *const end) 3560 { 3561 int i; 3562 const mDNSu8 *ptr = LocateAnswers(msg, end); 3563 for (i = 0; i < msg->h.numAnswers && ptr; i++) ptr = skipResourceRecord(msg, ptr, end); 3564 return(ptr); 3565 } 3566 3567 mDNSexport const mDNSu8 *LocateAdditionals(const DNSMessage *const msg, const mDNSu8 *const end) 3568 { 3569 int i; 3570 const mDNSu8 *ptr = LocateAuthorities(msg, end); 3571 for (i = 0; i < msg->h.numAuthorities; i++) ptr = skipResourceRecord(msg, ptr, end); 3572 return (ptr); 3573 } 3574 3575 mDNSexport const mDNSu8 *LocateOptRR(const DNSMessage *const msg, const mDNSu8 *const end, int minsize) 3576 { 3577 int i; 3578 const mDNSu8 *ptr = LocateAdditionals(msg, end); 3579 3580 // Locate the OPT record. 3581 // According to RFC 2671, "One OPT pseudo-RR can be added to the additional data section of either a request or a response." 3582 // This implies that there may be *at most* one OPT record per DNS message, in the Additional Section, 3583 // but not necessarily the *last* entry in the Additional Section. 3584 for (i = 0; ptr && i < msg->h.numAdditionals; i++) 3585 { 3586 if (ptr + DNSOpt_Header_Space + minsize <= end && // Make sure we have 11+minsize bytes of data 3587 ptr[0] == 0 && // Name must be root label 3588 ptr[1] == (kDNSType_OPT >> 8 ) && // rrtype OPT 3589 ptr[2] == (kDNSType_OPT & 0xFF) && 3590 ((mDNSu16)ptr[9] << 8 | (mDNSu16)ptr[10]) >= (mDNSu16)minsize) 3591 return(ptr); 3592 else 3593 ptr = skipResourceRecord(msg, ptr, end); 3594 } 3595 return(mDNSNULL); 3596 } 3597 3598 // On success, GetLLQOptData returns pointer to storage within shared "m->rec"; 3599 // it is caller's responsibilty to clear m->rec.r.resrec.RecordType after use 3600 // Note: An OPT RDataBody actually contains one or more variable-length rdataOPT objects packed together 3601 // The code that currently calls this assumes there's only one, instead of iterating through the set 3602 mDNSexport const rdataOPT *GetLLQOptData(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *const end) 3603 { 3604 const mDNSu8 *ptr = LocateOptRR(msg, end, DNSOpt_LLQData_Space); 3605 if (ptr) 3606 { 3607 ptr = GetLargeResourceRecord(m, msg, ptr, end, 0, kDNSRecordTypePacketAdd, &m->rec); 3608 if (ptr && m->rec.r.resrec.RecordType != kDNSRecordTypePacketNegative) return(&m->rec.r.resrec.rdata->u.opt[0]); 3609 } 3610 return(mDNSNULL); 3611 } 3612 3613 // Get the lease life of records in a dynamic update 3614 // returns 0 on error or if no lease present 3615 mDNSexport mDNSu32 GetPktLease(mDNS *m, DNSMessage *msg, const mDNSu8 *end) 3616 { 3617 mDNSu32 result = 0; 3618 const mDNSu8 *ptr = LocateOptRR(msg, end, DNSOpt_LeaseData_Space); 3619 if (ptr) ptr = GetLargeResourceRecord(m, msg, ptr, end, 0, kDNSRecordTypePacketAdd, &m->rec); 3620 if (ptr && m->rec.r.resrec.rdlength >= DNSOpt_LeaseData_Space && m->rec.r.resrec.rdata->u.opt[0].opt == kDNSOpt_Lease) 3621 result = m->rec.r.resrec.rdata->u.opt[0].u.updatelease; 3622 m->rec.r.resrec.RecordType = 0; // Clear RecordType to show we're not still using it 3623 return(result); 3624 } 3625 3626 mDNSlocal const mDNSu8 *DumpRecords(mDNS *const m, const DNSMessage *const msg, const mDNSu8 *ptr, const mDNSu8 *const end, int count, char *label) 3627 { 3628 int i; 3629 LogMsg("%2d %s", count, label); 3630 for (i = 0; i < count && ptr; i++) 3631 { 3632 // This puts a LargeCacheRecord on the stack instead of using the shared m->rec storage, 3633 // but since it's only used for debugging (and probably only on OS X, not on 3634 // embedded systems) putting a 9kB object on the stack isn't a big problem. 3635 LargeCacheRecord largecr; 3636 ptr = GetLargeResourceRecord(m, msg, ptr, end, mDNSInterface_Any, kDNSRecordTypePacketAns, &largecr); 3637 if (ptr) LogMsg("%2d TTL%8d %s", i, largecr.r.resrec.rroriginalttl, CRDisplayString(m, &largecr.r)); 3638 } 3639 if (!ptr) LogMsg("DumpRecords: ERROR: Premature end of packet data"); 3640 return(ptr); 3641 } 3642 3643 #define DNS_OP_Name(X) ( \ 3644 (X) == kDNSFlag0_OP_StdQuery ? "" : \ 3645 (X) == kDNSFlag0_OP_Iquery ? "Iquery " : \ 3646 (X) == kDNSFlag0_OP_Status ? "Status " : \ 3647 (X) == kDNSFlag0_OP_Unused3 ? "Unused3 " : \ 3648 (X) == kDNSFlag0_OP_Notify ? "Notify " : \ 3649 (X) == kDNSFlag0_OP_Update ? "Update " : "?? " ) 3650 3651 #define DNS_RC_Name(X) ( \ 3652 (X) == kDNSFlag1_RC_NoErr ? "NoErr" : \ 3653 (X) == kDNSFlag1_RC_FormErr ? "FormErr" : \ 3654 (X) == kDNSFlag1_RC_ServFail ? "ServFail" : \ 3655 (X) == kDNSFlag1_RC_NXDomain ? "NXDomain" : \ 3656 (X) == kDNSFlag1_RC_NotImpl ? "NotImpl" : \ 3657 (X) == kDNSFlag1_RC_Refused ? "Refused" : \ 3658 (X) == kDNSFlag1_RC_YXDomain ? "YXDomain" : \ 3659 (X) == kDNSFlag1_RC_YXRRSet ? "YXRRSet" : \ 3660 (X) == kDNSFlag1_RC_NXRRSet ? "NXRRSet" : \ 3661 (X) == kDNSFlag1_RC_NotAuth ? "NotAuth" : \ 3662 (X) == kDNSFlag1_RC_NotZone ? "NotZone" : "??" ) 3663 3664 // Note: DumpPacket expects the packet header fields in host byte order, not network byte order 3665 mDNSexport void DumpPacket(mDNS *const m, mStatus status, mDNSBool sent, char *transport, 3666 const mDNSAddr *srcaddr, mDNSIPPort srcport, 3667 const mDNSAddr *dstaddr, mDNSIPPort dstport, const DNSMessage *const msg, const mDNSu8 *const end) 3668 { 3669 mDNSBool IsUpdate = ((msg->h.flags.b[0] & kDNSFlag0_OP_Mask) == kDNSFlag0_OP_Update); 3670 const mDNSu8 *ptr = msg->data; 3671 int i; 3672 DNSQuestion q; 3673 char tbuffer[64], sbuffer[64], dbuffer[64] = ""; 3674 if (!status) tbuffer[mDNS_snprintf(tbuffer, sizeof(tbuffer), sent ? "Sent" : "Received" )] = 0; 3675 else tbuffer[mDNS_snprintf(tbuffer, sizeof(tbuffer), "ERROR %d %sing", status, sent ? "Send" : "Receive")] = 0; 3676 if (sent) sbuffer[mDNS_snprintf(sbuffer, sizeof(sbuffer), "port " )] = 0; 3677 else sbuffer[mDNS_snprintf(sbuffer, sizeof(sbuffer), "%#a:", srcaddr)] = 0; 3678 if (dstaddr || !mDNSIPPortIsZero(dstport)) 3679 dbuffer[mDNS_snprintf(dbuffer, sizeof(dbuffer), " to %#a:%d", dstaddr, mDNSVal16(dstport))] = 0; 3680 3681 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 --", 3682 tbuffer, transport, 3683 DNS_OP_Name(msg->h.flags.b[0] & kDNSFlag0_OP_Mask), 3684 msg->h.flags.b[0] & kDNSFlag0_QR_Response ? "Response" : "Query", 3685 msg->h.flags.b[0], msg->h.flags.b[1], 3686 DNS_RC_Name(msg->h.flags.b[1] & kDNSFlag1_RC_Mask), 3687 msg->h.flags.b[1] & kDNSFlag1_RC_Mask, 3688 msg->h.flags.b[0] & kDNSFlag0_AA ? "AA " : "", 3689 msg->h.flags.b[0] & kDNSFlag0_TC ? "TC " : "", 3690 msg->h.flags.b[0] & kDNSFlag0_RD ? "RD " : "", 3691 msg->h.flags.b[1] & kDNSFlag1_RA ? "RA " : "", 3692 msg->h.flags.b[1] & kDNSFlag1_AD ? "AD " : "", 3693 msg->h.flags.b[1] & kDNSFlag1_CD ? "CD " : "", 3694 mDNSVal16(msg->h.id), 3695 end - msg->data, 3696 sbuffer, mDNSVal16(srcport), dbuffer, 3697 (msg->h.flags.b[0] & kDNSFlag0_TC) ? " (truncated)" : "" 3698 ); 3699 3700 LogMsg("%2d %s", msg->h.numQuestions, IsUpdate ? "Zone" : "Questions"); 3701 for (i = 0; i < msg->h.numQuestions && ptr; i++) 3702 { 3703 ptr = getQuestion(msg, ptr, end, mDNSInterface_Any, &q); 3704 if (ptr) LogMsg("%2d %##s %s", i, q.qname.c, DNSTypeName(q.qtype)); 3705 } 3706 ptr = DumpRecords(m, msg, ptr, end, msg->h.numAnswers, IsUpdate ? "Prerequisites" : "Answers"); 3707 ptr = DumpRecords(m, msg, ptr, end, msg->h.numAuthorities, IsUpdate ? "Updates" : "Authorities"); 3708 DumpRecords(m, msg, ptr, end, msg->h.numAdditionals, "Additionals"); 3709 LogMsg("--------------"); 3710 } 3711 3712 // *************************************************************************** 3713 #if COMPILER_LIKES_PRAGMA_MARK 3714 #pragma mark - 3715 #pragma mark - Packet Sending Functions 3716 #endif 3717 3718 // Stub definition of TCPSocket_struct so we can access flags field. (Rest of TCPSocket_struct is platform-dependent.) 3719 struct TCPSocket_struct { TCPSocketFlags flags; /* ... */ }; 3720 // Stub definition of UDPSocket_struct so we can access port field. (Rest of UDPSocket_struct is platform-dependent.) 3721 struct UDPSocket_struct { mDNSIPPort port; /* ... */ }; 3722 3723 // Note: When we sign a DNS message using DNSDigest_SignMessage(), the current real-time clock value is used, which 3724 // is why we generally defer signing until we send the message, to ensure the signature is as fresh as possible. 3725 mDNSexport mStatus mDNSSendDNSMessage(mDNS *const m, DNSMessage *const msg, mDNSu8 *end, 3726 mDNSInterfaceID InterfaceID, UDPSocket *src, const mDNSAddr *dst, 3727 mDNSIPPort dstport, TCPSocket *sock, DomainAuthInfo *authInfo, 3728 mDNSBool useBackgroundTrafficClass) 3729 { 3730 mStatus status = mStatus_NoError; 3731 const mDNSu16 numAdditionals = msg->h.numAdditionals; 3732 mDNSu8 *newend; 3733 mDNSu8 *limit = msg->data + AbsoluteMaxDNSMessageData; 3734 3735 #if APPLE_OSX_mDNSResponder 3736 // maintain outbound packet statistics 3737 if (mDNSOpaque16IsZero(msg->h.id)) 3738 m->MulticastPacketsSent++; 3739 else 3740 m->UnicastPacketsSent++; 3741 #endif // APPLE_OSX_mDNSResponder 3742 3743 // Zero-length message data is okay (e.g. for a DNS Update ack, where all we need is an ID and an error code 3744 if (end < msg->data || end - msg->data > AbsoluteMaxDNSMessageData) 3745 { 3746 LogMsg("mDNSSendDNSMessage: invalid message %p %p %d", msg->data, end, end - msg->data); 3747 return mStatus_BadParamErr; 3748 } 3749 3750 newend = putHINFO(m, msg, end, authInfo, limit); 3751 if (!newend) LogMsg("mDNSSendDNSMessage: putHINFO failed msg %p end %p, limit %p", msg->data, end, limit); // Not fatal 3752 else end = newend; 3753 3754 // Put all the integer values in IETF byte-order (MSB first, LSB second) 3755 SwapDNSHeaderBytes(msg); 3756 3757 if (authInfo) DNSDigest_SignMessage(msg, &end, authInfo, 0); // DNSDigest_SignMessage operates on message in network byte order 3758 if (!end) { LogMsg("mDNSSendDNSMessage: DNSDigest_SignMessage failed"); status = mStatus_NoMemoryErr; } 3759 else 3760 { 3761 // Send the packet on the wire 3762 if (!sock) 3763 status = mDNSPlatformSendUDP(m, msg, end, InterfaceID, src, dst, dstport, useBackgroundTrafficClass); 3764 else 3765 { 3766 mDNSu16 msglen = (mDNSu16)(end - (mDNSu8 *)msg); 3767 mDNSu8 lenbuf[2] = { (mDNSu8)(msglen >> 8), (mDNSu8)(msglen & 0xFF) }; 3768 char *buf; 3769 long nsent; 3770 3771 // Try to send them in one packet if we can allocate enough memory 3772 buf = mDNSPlatformMemAllocate(msglen + 2); 3773 if (buf) 3774 { 3775 buf[0] = lenbuf[0]; 3776 buf[1] = lenbuf[1]; 3777 mDNSPlatformMemCopy(buf+2, msg, msglen); 3778 nsent = mDNSPlatformWriteTCP(sock, buf, msglen+2); 3779 if (nsent != (msglen + 2)) 3780 { 3781 LogMsg("mDNSSendDNSMessage: write message failed %d/%d", nsent, msglen); 3782 status = mStatus_ConnFailed; 3783 } 3784 mDNSPlatformMemFree(buf); 3785 } 3786 else 3787 { 3788 nsent = mDNSPlatformWriteTCP(sock, (char*)lenbuf, 2); 3789 if (nsent != 2) 3790 { 3791 LogMsg("mDNSSendDNSMessage: write msg length failed %d/%d", nsent, 2); 3792 status = mStatus_ConnFailed; 3793 } 3794 else 3795 { 3796 nsent = mDNSPlatformWriteTCP(sock, (char *)msg, msglen); 3797 if (nsent != msglen) 3798 { 3799 LogMsg("mDNSSendDNSMessage: write msg body failed %d/%d", nsent, msglen); 3800 status = mStatus_ConnFailed; 3801 } 3802 } 3803 } 3804 } 3805 } 3806 3807 // Swap the integer values back the way they were (remember that numAdditionals may have been changed by putHINFO and/or SignMessage) 3808 SwapDNSHeaderBytes(msg); 3809 3810 // Dump the packet with the HINFO and TSIG 3811 if (mDNS_PacketLoggingEnabled && !mDNSOpaque16IsZero(msg->h.id)) { 3812 mDNSIPPort port = MulticastDNSPort; 3813 DumpPacket(m, status, mDNStrue, 3814 sock && (sock->flags & kTCPSocketFlags_UseTLS) ? 3815 "TLS" : sock ? "TCP" : "UDP", mDNSNULL, 3816 src ? src->port : port, dst, dstport, msg, end); 3817 } 3818 3819 // put the number of additionals back the way it was 3820 msg->h.numAdditionals = numAdditionals; 3821 3822 return(status); 3823 } 3824 3825 // *************************************************************************** 3826 #if COMPILER_LIKES_PRAGMA_MARK 3827 #pragma mark - 3828 #pragma mark - RR List Management & Task Management 3829 #endif 3830 3831 mDNSexport void mDNS_Lock_(mDNS *const m, const char * const functionname) 3832 { 3833 // MUST grab the platform lock FIRST! 3834 mDNSPlatformLock(m); 3835 3836 // Normally, mDNS_reentrancy is zero and so is mDNS_busy 3837 // However, when we call a client callback mDNS_busy is one, and we increment mDNS_reentrancy too 3838 // If that client callback does mDNS API calls, mDNS_reentrancy and mDNS_busy will both be one 3839 // If mDNS_busy != mDNS_reentrancy that's a bad sign 3840 if (m->mDNS_busy != m->mDNS_reentrancy) 3841 LogFatalError("%s: mDNS_Lock: Locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", functionname, m->mDNS_busy, m->mDNS_reentrancy); 3842 3843 // If this is an initial entry into the mDNSCore code, set m->timenow 3844 // else, if this is a re-entrant entry into the mDNSCore code, m->timenow should already be set 3845 if (m->mDNS_busy == 0) 3846 { 3847 if (m->timenow) 3848 LogMsg("%s: mDNS_Lock: m->timenow already set (%ld/%ld)", functionname, m->timenow, mDNS_TimeNow_NoLock(m)); 3849 m->timenow = mDNS_TimeNow_NoLock(m); 3850 if (m->timenow == 0) m->timenow = 1; 3851 } 3852 else if (m->timenow == 0) 3853 { 3854 LogMsg("%s: mDNS_Lock: m->mDNS_busy is %ld but m->timenow not set", functionname, m->mDNS_busy); 3855 m->timenow = mDNS_TimeNow_NoLock(m); 3856 if (m->timenow == 0) m->timenow = 1; 3857 } 3858 3859 if (m->timenow_last - m->timenow > 0) 3860 { 3861 m->timenow_adjust += m->timenow_last - m->timenow; 3862 LogMsg("%s: mDNSPlatformRawTime went backwards by %ld ticks; setting correction factor to %ld", functionname, m->timenow_last - m->timenow, m->timenow_adjust); 3863 m->timenow = m->timenow_last; 3864 } 3865 m->timenow_last = m->timenow; 3866 3867 // Increment mDNS_busy so we'll recognise re-entrant calls 3868 m->mDNS_busy++; 3869 } 3870 3871 mDNSlocal AuthRecord *AnyLocalRecordReady(const mDNS *const m) 3872 { 3873 AuthRecord *rr; 3874 for (rr = m->NewLocalRecords; rr; rr = rr->next) 3875 if (LocalRecordReady(rr)) return rr; 3876 return mDNSNULL; 3877 } 3878 3879 mDNSlocal mDNSs32 GetNextScheduledEvent(const mDNS *const m) 3880 { 3881 mDNSs32 e = m->timenow + 0x78000000; 3882 if (m->mDNSPlatformStatus != mStatus_NoError) return(e); 3883 if (m->NewQuestions) 3884 { 3885 if (m->NewQuestions->DelayAnswering) e = m->NewQuestions->DelayAnswering; 3886 else return(m->timenow); 3887 } 3888 if (m->NewLocalOnlyQuestions) return(m->timenow); 3889 if (m->NewLocalRecords && AnyLocalRecordReady(m)) return(m->timenow); 3890 if (m->NewLocalOnlyRecords) return(m->timenow); 3891 if (m->SPSProxyListChanged) return(m->timenow); 3892 if (m->LocalRemoveEvents) return(m->timenow); 3893 3894 #ifndef UNICAST_DISABLED 3895 if (e - m->NextuDNSEvent > 0) e = m->NextuDNSEvent; 3896 if (e - m->NextScheduledNATOp > 0) e = m->NextScheduledNATOp; 3897 if (m->NextSRVUpdate && e - m->NextSRVUpdate > 0) e = m->NextSRVUpdate; 3898 #endif 3899 3900 if (e - m->NextCacheCheck > 0) e = m->NextCacheCheck; 3901 if (e - m->NextScheduledSPS > 0) e = m->NextScheduledSPS; 3902 if (e - m->NextScheduledKA > 0) e = m->NextScheduledKA; 3903 3904 // NextScheduledSPRetry only valid when DelaySleep not set 3905 if (!m->DelaySleep && m->SleepLimit && e - m->NextScheduledSPRetry > 0) e = m->NextScheduledSPRetry; 3906 if (m->DelaySleep && e - m->DelaySleep > 0) e = m->DelaySleep; 3907 3908 if (m->SuppressSending) 3909 { 3910 if (e - m->SuppressSending > 0) e = m->SuppressSending; 3911 } 3912 else 3913 { 3914 if (e - m->NextScheduledQuery > 0) e = m->NextScheduledQuery; 3915 if (e - m->NextScheduledProbe > 0) e = m->NextScheduledProbe; 3916 if (e - m->NextScheduledResponse > 0) e = m->NextScheduledResponse; 3917 } 3918 if (e - m->NextScheduledStopTime > 0) e = m->NextScheduledStopTime; 3919 return(e); 3920 } 3921 3922 #define LogTSE TSE++,LogMsg 3923 3924 mDNSexport void ShowTaskSchedulingError(mDNS *const m) 3925 { 3926 int TSE = 0; 3927 AuthRecord *rr; 3928 mDNS_Lock(m); 3929 3930 LogMsg("Task Scheduling Error: *** Continuously busy for more than a second"); 3931 3932 // Note: To accurately diagnose *why* we're busy, the debugging code here needs to mirror the logic in GetNextScheduledEvent above 3933 3934 if (m->NewQuestions && (!m->NewQuestions->DelayAnswering || m->timenow - m->NewQuestions->DelayAnswering >= 0)) 3935 LogTSE("Task Scheduling Error: NewQuestion %##s (%s)", 3936 m->NewQuestions->qname.c, DNSTypeName(m->NewQuestions->qtype)); 3937 3938 if (m->NewLocalOnlyQuestions) 3939 LogTSE("Task Scheduling Error: NewLocalOnlyQuestions %##s (%s)", 3940 m->NewLocalOnlyQuestions->qname.c, DNSTypeName(m->NewLocalOnlyQuestions->qtype)); 3941 3942 if (m->NewLocalRecords) 3943 { 3944 rr = AnyLocalRecordReady(m); 3945 if (rr) LogTSE("Task Scheduling Error: NewLocalRecords %s", ARDisplayString(m, rr)); 3946 } 3947 3948 if (m->NewLocalOnlyRecords) LogTSE("Task Scheduling Error: NewLocalOnlyRecords"); 3949 3950 if (m->SPSProxyListChanged) LogTSE("Task Scheduling Error: SPSProxyListChanged"); 3951 3952 if (m->LocalRemoveEvents) LogTSE("Task Scheduling Error: LocalRemoveEvents"); 3953 3954 #ifndef UNICAST_DISABLED 3955 if (m->timenow - m->NextuDNSEvent >= 0) 3956 LogTSE("Task Scheduling Error: m->NextuDNSEvent %d", m->timenow - m->NextuDNSEvent); 3957 if (m->timenow - m->NextScheduledNATOp >= 0) 3958 LogTSE("Task Scheduling Error: m->NextScheduledNATOp %d", m->timenow - m->NextScheduledNATOp); 3959 if (m->NextSRVUpdate && m->timenow - m->NextSRVUpdate >= 0) 3960 LogTSE("Task Scheduling Error: m->NextSRVUpdate %d", m->timenow - m->NextSRVUpdate); 3961 #endif 3962 3963 if (m->timenow - m->NextCacheCheck >= 0) 3964 LogTSE("Task Scheduling Error: m->NextCacheCheck %d", m->timenow - m->NextCacheCheck); 3965 if (m->timenow - m->NextScheduledSPS >= 0) 3966 LogTSE("Task Scheduling Error: m->NextScheduledSPS %d", m->timenow - m->NextScheduledSPS); 3967 if (m->timenow - m->NextScheduledKA >= 0) 3968 LogTSE("Task Scheduling Error: m->NextScheduledKA %d", m->timenow - m->NextScheduledKA); 3969 if (!m->DelaySleep && m->SleepLimit && m->timenow - m->NextScheduledSPRetry >= 0) 3970 LogTSE("Task Scheduling Error: m->NextScheduledSPRetry %d", m->timenow - m->NextScheduledSPRetry); 3971 if (m->DelaySleep && m->timenow - m->DelaySleep >= 0) 3972 LogTSE("Task Scheduling Error: m->DelaySleep %d", m->timenow - m->DelaySleep); 3973 3974 if (m->SuppressSending && m->timenow - m->SuppressSending >= 0) 3975 LogTSE("Task Scheduling Error: m->SuppressSending %d", m->timenow - m->SuppressSending); 3976 if (m->timenow - m->NextScheduledQuery >= 0) 3977 LogTSE("Task Scheduling Error: m->NextScheduledQuery %d", m->timenow - m->NextScheduledQuery); 3978 if (m->timenow - m->NextScheduledProbe >= 0) 3979 LogTSE("Task Scheduling Error: m->NextScheduledProbe %d", m->timenow - m->NextScheduledProbe); 3980 if (m->timenow - m->NextScheduledResponse >= 0) 3981 LogTSE("Task Scheduling Error: m->NextScheduledResponse %d", m->timenow - m->NextScheduledResponse); 3982 if (m->timenow - m->NextScheduledStopTime >= 0) 3983 LogTSE("Task Scheduling Error: m->NextScheduledStopTime %d", m->timenow - m->NextScheduledStopTime); 3984 3985 if (m->timenow - m->NextScheduledEvent >= 0) 3986 LogTSE("Task Scheduling Error: m->NextScheduledEvent %d", m->timenow - m->NextScheduledEvent); 3987 3988 if (m->NetworkChanged && m->timenow - m->NetworkChanged >= 0) 3989 LogTSE("Task Scheduling Error: NetworkChanged %d", m->timenow - m->NetworkChanged); 3990 3991 if (!TSE) LogMsg("Task Scheduling Error: *** No likely causes identified"); 3992 else LogMsg("Task Scheduling Error: *** %d potential cause%s identified (significant only if the same cause consistently appears)", TSE, TSE > 1 ? "s" : ""); 3993 3994 mDNS_Unlock(m); 3995 } 3996 3997 mDNSexport void mDNS_Unlock_(mDNS *const m, const char *const functionname) 3998 { 3999 // Decrement mDNS_busy 4000 m->mDNS_busy--; 4001 4002 // Check for locking failures 4003 if (m->mDNS_busy != m->mDNS_reentrancy) 4004 LogFatalError("%s: mDNS_Unlock: Locking failure! mDNS_busy (%ld) != mDNS_reentrancy (%ld)", functionname, m->mDNS_busy, m->mDNS_reentrancy); 4005 4006 // If this is a final exit from the mDNSCore code, set m->NextScheduledEvent and clear m->timenow 4007 if (m->mDNS_busy == 0) 4008 { 4009 m->NextScheduledEvent = GetNextScheduledEvent(m); 4010 if (m->timenow == 0) LogMsg("%s: mDNS_Unlock: ERROR! m->timenow aready zero", functionname); 4011 m->timenow = 0; 4012 } 4013 4014 // MUST release the platform lock LAST! 4015 mDNSPlatformUnlock(m); 4016 } 4017 4018 // *************************************************************************** 4019 #if COMPILER_LIKES_PRAGMA_MARK 4020 #pragma mark - 4021 #pragma mark - Specialized mDNS version of vsnprintf 4022 #endif 4023 4024 static const struct mDNSprintf_format 4025 { 4026 unsigned leftJustify : 1; 4027 unsigned forceSign : 1; 4028 unsigned zeroPad : 1; 4029 unsigned havePrecision : 1; 4030 unsigned hSize : 1; 4031 unsigned lSize : 1; 4032 char altForm; 4033 char sign; // +, - or space 4034 unsigned int fieldWidth; 4035 unsigned int precision; 4036 } mDNSprintf_format_default = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; 4037 4038 mDNSexport mDNSu32 mDNS_vsnprintf(char *sbuffer, mDNSu32 buflen, const char *fmt, va_list arg) 4039 { 4040 mDNSu32 nwritten = 0; 4041 int c; 4042 if (buflen == 0) return(0); 4043 buflen--; // Pre-reserve one space in the buffer for the terminating null 4044 if (buflen == 0) goto exit; 4045 4046 for (c = *fmt; c != 0; c = *++fmt) 4047 { 4048 if (c != '%') 4049 { 4050 *sbuffer++ = (char)c; 4051 if (++nwritten >= buflen) goto exit; 4052 } 4053 else 4054 { 4055 unsigned int i=0, j; 4056 // The mDNS Vsprintf Argument Conversion Buffer is used as a temporary holding area for 4057 // generating decimal numbers, hexdecimal numbers, IP addresses, domain name strings, etc. 4058 // The size needs to be enough for a 256-byte domain name plus some error text. 4059 #define mDNS_VACB_Size 300 4060 char mDNS_VACB[mDNS_VACB_Size]; 4061 #define mDNS_VACB_Lim (&mDNS_VACB[mDNS_VACB_Size]) 4062 #define mDNS_VACB_Remain(s) ((mDNSu32)(mDNS_VACB_Lim - s)) 4063 char *s = mDNS_VACB_Lim, *digits; 4064 struct mDNSprintf_format F = mDNSprintf_format_default; 4065 4066 while (1) // decode flags 4067 { 4068 c = *++fmt; 4069 if (c == '-') F.leftJustify = 1; 4070 else if (c == '+') F.forceSign = 1; 4071 else if (c == ' ') F.sign = ' '; 4072 else if (c == '#') F.altForm++; 4073 else if (c == '0') F.zeroPad = 1; 4074 else break; 4075 } 4076 4077 if (c == '*') // decode field width 4078 { 4079 int f = va_arg(arg, int); 4080 if (f < 0) { f = -f; F.leftJustify = 1; } 4081 F.fieldWidth = (unsigned int)f; 4082 c = *++fmt; 4083 } 4084 else 4085 { 4086 for (; c >= '0' && c <= '9'; c = *++fmt) 4087 F.fieldWidth = (10 * F.fieldWidth) + (c - '0'); 4088 } 4089 4090 if (c == '.') // decode precision 4091 { 4092 if ((c = *++fmt) == '*') 4093 { F.precision = va_arg(arg, unsigned int); c = *++fmt; } 4094 else for (; c >= '0' && c <= '9'; c = *++fmt) 4095 F.precision = (10 * F.precision) + (c - '0'); 4096 F.havePrecision = 1; 4097 } 4098 4099 if (F.leftJustify) F.zeroPad = 0; 4100 4101 conv: 4102 switch (c) // perform appropriate conversion 4103 { 4104 unsigned long n; 4105 case 'h': F.hSize = 1; c = *++fmt; goto conv; 4106 case 'l': // fall through 4107 case 'L': F.lSize = 1; c = *++fmt; goto conv; 4108 case 'd': 4109 case 'i': if (F.lSize) n = (unsigned long)va_arg(arg, long); 4110 else n = (unsigned long)va_arg(arg, int); 4111 if (F.hSize) n = (short) n; 4112 if ((long) n < 0) { n = (unsigned long)-(long)n; F.sign = '-'; } 4113 else if (F.forceSign) F.sign = '+'; 4114 goto decimal; 4115 case 'u': if (F.lSize) n = va_arg(arg, unsigned long); 4116 else n = va_arg(arg, unsigned int); 4117 if (F.hSize) n = (unsigned short) n; 4118 F.sign = 0; 4119 goto decimal; 4120 decimal: if (!F.havePrecision) 4121 { 4122 if (F.zeroPad) 4123 { 4124 F.precision = F.fieldWidth; 4125 if (F.sign) --F.precision; 4126 } 4127 if (F.precision < 1) F.precision = 1; 4128 } 4129 if (F.precision > mDNS_VACB_Size - 1) 4130 F.precision = mDNS_VACB_Size - 1; 4131 for (i = 0; n; n /= 10, i++) *--s = (char)(n % 10 + '0'); 4132 for (; i < F.precision; i++) *--s = '0'; 4133 if (F.sign) { *--s = F.sign; i++; } 4134 break; 4135 4136 case 'o': if (F.lSize) n = va_arg(arg, unsigned long); 4137 else n = va_arg(arg, unsigned int); 4138 if (F.hSize) n = (unsigned short) n; 4139 if (!F.havePrecision) 4140 { 4141 if (F.zeroPad) F.precision = F.fieldWidth; 4142 if (F.precision < 1) F.precision = 1; 4143 } 4144 if (F.precision > mDNS_VACB_Size - 1) 4145 F.precision = mDNS_VACB_Size - 1; 4146 for (i = 0; n; n /= 8, i++) *--s = (char)(n % 8 + '0'); 4147 if (F.altForm && i && *s != '0') { *--s = '0'; i++; } 4148 for (; i < F.precision; i++) *--s = '0'; 4149 break; 4150 4151 case 'a': { 4152 unsigned char *a = va_arg(arg, unsigned char *); 4153 if (!a) { static char emsg[] = "<<NULL>>"; s = emsg; i = sizeof(emsg)-1; } 4154 else 4155 { 4156 s = mDNS_VACB; // Adjust s to point to the start of the buffer, not the end 4157 if (F.altForm) 4158 { 4159 mDNSAddr *ip = (mDNSAddr*)a; 4160 switch (ip->type) 4161 { 4162 case mDNSAddrType_IPv4: F.precision = 4; a = (unsigned char *)&ip->ip.v4; break; 4163 case mDNSAddrType_IPv6: F.precision = 16; a = (unsigned char *)&ip->ip.v6; break; 4164 default: F.precision = 0; break; 4165 } 4166 } 4167 if (F.altForm && !F.precision) 4168 i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "«ZERO ADDRESS»"); 4169 else switch (F.precision) 4170 { 4171 case 4: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%d.%d.%d.%d", 4172 a[0], a[1], a[2], a[3]); break; 4173 case 6: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%02X:%02X:%02X:%02X:%02X:%02X", 4174 a[0], a[1], a[2], a[3], a[4], a[5]); break; 4175 case 16: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), 4176 "%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X", 4177 a[0x0], a[0x1], a[0x2], a[0x3], a[0x4], a[0x5], a[0x6], a[0x7], 4178 a[0x8], a[0x9], a[0xA], a[0xB], a[0xC], a[0xD], a[0xE], a[0xF]); break; 4179 default: i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "%s", "<< ERROR: Must specify" 4180 " address size (i.e. %.4a=IPv4, %.6a=Ethernet, %.16a=IPv6) >>"); break; 4181 } 4182 } 4183 } 4184 break; 4185 4186 case 'p': F.havePrecision = F.lSize = 1; 4187 F.precision = sizeof(void*) * 2; // 8 characters on 32-bit; 16 characters on 64-bit 4188 case 'X': digits = "0123456789ABCDEF"; 4189 goto hexadecimal; 4190 case 'x': digits = "0123456789abcdef"; 4191 hexadecimal: if (F.lSize) n = va_arg(arg, unsigned long); 4192 else n = va_arg(arg, unsigned int); 4193 if (F.hSize) n = (unsigned short) n; 4194 if (!F.havePrecision) 4195 { 4196 if (F.zeroPad) 4197 { 4198 F.precision = F.fieldWidth; 4199 if (F.altForm) F.precision -= 2; 4200 } 4201 if (F.precision < 1) F.precision = 1; 4202 } 4203 if (F.precision > mDNS_VACB_Size - 1) 4204 F.precision = mDNS_VACB_Size - 1; 4205 for (i = 0; n; n /= 16, i++) *--s = digits[n % 16]; 4206 for (; i < F.precision; i++) *--s = '0'; 4207 if (F.altForm) { *--s = (char)c; *--s = '0'; i += 2; } 4208 break; 4209 4210 case 'c': *--s = (char)va_arg(arg, int); i = 1; break; 4211 4212 case 's': s = va_arg(arg, char *); 4213 if (!s) { static char emsg[] = "<<NULL>>"; s = emsg; i = sizeof(emsg)-1; } 4214 else switch (F.altForm) 4215 { 4216 case 0: i=0; 4217 if (!F.havePrecision) // C string 4218 while (s[i]) i++; 4219 else 4220 { 4221 while ((i < F.precision) && s[i]) i++; 4222 // Make sure we don't truncate in the middle of a UTF-8 character 4223 // If last character we got was any kind of UTF-8 multi-byte character, 4224 // then see if we have to back up. 4225 // This is not as easy as the similar checks below, because 4226 // here we can't assume it's safe to examine the *next* byte, so we 4227 // have to confine ourselves to working only backwards in the string. 4228 j = i; // Record where we got to 4229 // Now, back up until we find first non-continuation-char 4230 while (i>0 && (s[i-1] & 0xC0) == 0x80) i--; 4231 // Now s[i-1] is the first non-continuation-char 4232 // and (j-i) is the number of continuation-chars we found 4233 if (i>0 && (s[i-1] & 0xC0) == 0xC0) // If we found a start-char 4234 { 4235 i--; // Tentatively eliminate this start-char as well 4236 // Now (j-i) is the number of characters we're considering eliminating. 4237 // To be legal UTF-8, the start-char must contain (j-i) one-bits, 4238 // followed by a zero bit. If we shift it right by (7-(j-i)) bits 4239 // (with sign extension) then the result has to be 0xFE. 4240 // If this is right, then we reinstate the tentatively eliminated bytes. 4241 if (((j-i) < 7) && (((s[i] >> (7-(j-i))) & 0xFF) == 0xFE)) i = j; 4242 } 4243 } 4244 break; 4245 case 1: i = (unsigned char) *s++; break; // Pascal string 4246 case 2: { // DNS label-sequence name 4247 unsigned char *a = (unsigned char *)s; 4248 s = mDNS_VACB; // Adjust s to point to the start of the buffer, not the end 4249 if (*a == 0) *s++ = '.'; // Special case for root DNS name 4250 while (*a) 4251 { 4252 char buf[63*4+1]; 4253 if (*a > 63) 4254 { s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "<<INVALID LABEL LENGTH %u>>", *a); break; } 4255 if (s + *a >= &mDNS_VACB[254]) 4256 { s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "<<NAME TOO LONG>>"); break; } 4257 // Need to use ConvertDomainLabelToCString to do proper escaping here, 4258 // so it's clear what's a literal dot and what's a label separator 4259 ConvertDomainLabelToCString((domainlabel*)a, buf); 4260 s += mDNS_snprintf(s, mDNS_VACB_Remain(s), "%s.", buf); 4261 a += 1 + *a; 4262 } 4263 i = (mDNSu32)(s - mDNS_VACB); 4264 s = mDNS_VACB; // Reset s back to the start of the buffer 4265 break; 4266 } 4267 } 4268 // Make sure we don't truncate in the middle of a UTF-8 character (see similar comment below) 4269 if (F.havePrecision && i > F.precision) 4270 { i = F.precision; while (i>0 && (s[i] & 0xC0) == 0x80) i--;} 4271 break; 4272 4273 case 'n': s = va_arg(arg, char *); 4274 if (F.hSize) *(short *) s = (short)nwritten; 4275 else if (F.lSize) *(long *) s = (long)nwritten; 4276 else *(int *) s = (int)nwritten; 4277 continue; 4278 4279 default: s = mDNS_VACB; 4280 i = mDNS_snprintf(mDNS_VACB, sizeof(mDNS_VACB), "<<UNKNOWN FORMAT CONVERSION CODE %%%c>>", c); 4281 4282 case '%': *sbuffer++ = (char)c; 4283 if (++nwritten >= buflen) goto exit; 4284 break; 4285 } 4286 4287 if (i < F.fieldWidth && !F.leftJustify) // Pad on the left 4288 do { 4289 *sbuffer++ = ' '; 4290 if (++nwritten >= buflen) goto exit; 4291 } while (i < --F.fieldWidth); 4292 4293 // Make sure we don't truncate in the middle of a UTF-8 character. 4294 // Note: s[i] is the first eliminated character; i.e. the next character *after* the last character of the 4295 // allowed output. If s[i] is a UTF-8 continuation character, then we've cut a unicode character in half, 4296 // so back up 'i' until s[i] is no longer a UTF-8 continuation character. (if the input was proprly 4297 // formed, s[i] will now be the UTF-8 start character of the multi-byte character we just eliminated). 4298 if (i > buflen - nwritten) 4299 { i = buflen - nwritten; while (i>0 && (s[i] & 0xC0) == 0x80) i--;} 4300 for (j=0; j<i; j++) *sbuffer++ = *s++; // Write the converted result 4301 nwritten += i; 4302 if (nwritten >= buflen) goto exit; 4303 4304 for (; i < F.fieldWidth; i++) // Pad on the right 4305 { 4306 *sbuffer++ = ' '; 4307 if (++nwritten >= buflen) goto exit; 4308 } 4309 } 4310 } 4311 exit: 4312 *sbuffer++ = 0; 4313 return(nwritten); 4314 } 4315 4316 mDNSexport mDNSu32 mDNS_snprintf(char *sbuffer, mDNSu32 buflen, const char *fmt, ...) 4317 { 4318 mDNSu32 length; 4319 4320 va_list ptr; 4321 va_start(ptr,fmt); 4322 length = mDNS_vsnprintf(sbuffer, buflen, fmt, ptr); 4323 va_end(ptr); 4324 4325 return(length); 4326 } 4327