1 /* -*- Mode: C; tab-width: 4 -*- 2 * 3 * Copyright (c) 2002-2004 Apple Computer, Inc. All rights reserved. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 * Formatting notes: 18 * This code follows the "Whitesmiths style" C indentation rules. Plenty of discussion 19 * on C indentation can be found on the web, such as <http://www.kafejo.com/komp/1tbs.htm>, 20 * but for the sake of brevity here I will say just this: Curly braces are not syntactially 21 * part of an "if" statement; they are the beginning and ending markers of a compound statement; 22 * therefore common sense dictates that if they are part of a compound statement then they 23 * should be indented to the same level as everything else in that compound statement. 24 * Indenting curly braces at the same level as the "if" implies that curly braces are 25 * part of the "if", which is false. (This is as misleading as people who write "char* x,y;" 26 * thinking that variables x and y are both of type "char*" -- and anyone who doesn't 27 * understand why variable y is not of type "char*" just proves the point that poor code 28 * layout leads people to unfortunate misunderstandings about how the C language really works.) 29 */ 30 31 #include "mDNSEmbeddedAPI.h" // Defines the interface provided to the client layer above 32 #include "DNSCommon.h" 33 #include "mDNSPosix.h" // Defines the specific types needed to run mDNS on this platform 34 #include "dns_sd.h" 35 36 #include <assert.h> 37 #include <stdio.h> 38 #include <stdlib.h> 39 #include <errno.h> 40 #include <string.h> 41 #include <unistd.h> 42 #ifndef __ANDROID__ 43 #include <syslog.h> 44 #endif 45 #include <stdarg.h> 46 #include <fcntl.h> 47 #include <sys/types.h> 48 #include <sys/time.h> 49 #include <sys/socket.h> 50 #include <sys/uio.h> 51 #include <sys/select.h> 52 #include <netinet/in.h> 53 #include <arpa/inet.h> 54 #include <time.h> // platform support for UTC time 55 56 #if USES_NETLINK 57 #include <asm/types.h> 58 #include <linux/netlink.h> 59 #include <linux/rtnetlink.h> 60 #else // USES_NETLINK 61 #include <net/route.h> 62 #include <net/if.h> 63 #endif // USES_NETLINK 64 65 #include "mDNSUNP.h" 66 #include "GenLinkedList.h" 67 68 // Disallow SO_REUSEPORT on Android because we use >3.9 kernel headers to build binaries targeted to 3.4.x. 69 #ifdef __ANDROID__ 70 #undef SO_REUSEPORT 71 #endif 72 73 // __ANDROID__ : replaced assert(close(..)) at several points in this file. 74 75 // *************************************************************************** 76 // Structures 77 78 // We keep a list of client-supplied event sources in PosixEventSource records 79 struct PosixEventSource 80 { 81 mDNSPosixEventCallback Callback; 82 void *Context; 83 int fd; 84 struct PosixEventSource *Next; 85 }; 86 typedef struct PosixEventSource PosixEventSource; 87 88 // Context record for interface change callback 89 struct IfChangeRec 90 { 91 int NotifySD; 92 mDNS *mDNS; 93 }; 94 typedef struct IfChangeRec IfChangeRec; 95 96 // Note that static data is initialized to zero in (modern) C. 97 static fd_set gEventFDs; 98 static int gMaxFD; // largest fd in gEventFDs 99 static GenLinkedList gEventSources; // linked list of PosixEventSource's 100 static sigset_t gEventSignalSet; // Signals which event loop listens for 101 static sigset_t gEventSignals; // Signals which were received while inside loop 102 103 // *************************************************************************** 104 // Globals (for debugging) 105 106 static int num_registered_interfaces = 0; 107 static int num_pkts_accepted = 0; 108 static int num_pkts_rejected = 0; 109 110 // *************************************************************************** 111 // Functions 112 113 int gMDNSPlatformPosixVerboseLevel = 0; 114 115 #define PosixErrorToStatus(errNum) ((errNum) == 0 ? mStatus_NoError : mStatus_UnknownErr) 116 117 mDNSlocal void SockAddrTomDNSAddr(const struct sockaddr *const sa, mDNSAddr *ipAddr, mDNSIPPort *ipPort) 118 { 119 switch (sa->sa_family) 120 { 121 case AF_INET: 122 { 123 struct sockaddr_in *sin = (struct sockaddr_in*)sa; 124 ipAddr->type = mDNSAddrType_IPv4; 125 ipAddr->ip.v4.NotAnInteger = sin->sin_addr.s_addr; 126 if (ipPort) ipPort->NotAnInteger = sin->sin_port; 127 break; 128 } 129 130 #if HAVE_IPV6 131 case AF_INET6: 132 { 133 struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)sa; 134 #ifndef NOT_HAVE_SA_LEN 135 assert(sin6->sin6_len == sizeof(*sin6)); 136 #endif 137 ipAddr->type = mDNSAddrType_IPv6; 138 ipAddr->ip.v6 = *(mDNSv6Addr*)&sin6->sin6_addr; 139 if (ipPort) ipPort->NotAnInteger = sin6->sin6_port; 140 break; 141 } 142 #endif 143 144 default: 145 verbosedebugf("SockAddrTomDNSAddr: Uknown address family %d\n", sa->sa_family); 146 ipAddr->type = mDNSAddrType_None; 147 if (ipPort) ipPort->NotAnInteger = 0; 148 break; 149 } 150 } 151 152 #if COMPILER_LIKES_PRAGMA_MARK 153 #pragma mark ***** Send and Receive 154 #endif 155 156 // mDNS core calls this routine when it needs to send a packet. 157 mDNSexport mStatus mDNSPlatformSendUDP(const mDNS *const m, const void *const msg, const mDNSu8 *const end, 158 mDNSInterfaceID InterfaceID, UDPSocket *src, const mDNSAddr *dst, mDNSIPPort dstPort) 159 { 160 int err = 0; 161 struct sockaddr_storage to; 162 PosixNetworkInterface * thisIntf = (PosixNetworkInterface *)(InterfaceID); 163 int sendingsocket = -1; 164 165 (void)src; // Will need to use this parameter once we implement mDNSPlatformUDPSocket/mDNSPlatformUDPClose 166 167 assert(m != NULL); 168 assert(msg != NULL); 169 assert(end != NULL); 170 assert((((char *) end) - ((char *) msg)) > 0); 171 172 if (dstPort.NotAnInteger == 0) 173 { 174 LogMsg("mDNSPlatformSendUDP: Invalid argument -dstPort is set to 0"); 175 return PosixErrorToStatus(EINVAL); 176 } 177 if (dst->type == mDNSAddrType_IPv4) 178 { 179 struct sockaddr_in *sin = (struct sockaddr_in*)&to; 180 #ifndef NOT_HAVE_SA_LEN 181 sin->sin_len = sizeof(*sin); 182 #endif 183 sin->sin_family = AF_INET; 184 sin->sin_port = dstPort.NotAnInteger; 185 sin->sin_addr.s_addr = dst->ip.v4.NotAnInteger; 186 sendingsocket = thisIntf ? thisIntf->multicastSocket4 : m->p->unicastSocket4; 187 } 188 189 #if HAVE_IPV6 190 else if (dst->type == mDNSAddrType_IPv6) 191 { 192 struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&to; 193 mDNSPlatformMemZero(sin6, sizeof(*sin6)); 194 #ifndef NOT_HAVE_SA_LEN 195 sin6->sin6_len = sizeof(*sin6); 196 #endif 197 sin6->sin6_family = AF_INET6; 198 sin6->sin6_port = dstPort.NotAnInteger; 199 sin6->sin6_addr = *(struct in6_addr*)&dst->ip.v6; 200 sendingsocket = thisIntf ? thisIntf->multicastSocket6 : m->p->unicastSocket6; 201 } 202 #endif 203 204 if (sendingsocket >= 0) 205 err = sendto(sendingsocket, msg, (char*)end - (char*)msg, 0, (struct sockaddr *)&to, GET_SA_LEN(to)); 206 207 if (err > 0) err = 0; 208 else if (err < 0) 209 { 210 static int MessageCount = 0; 211 // Don't report EHOSTDOWN (i.e. ARP failure), ENETDOWN, or no route to host for unicast destinations 212 if (!mDNSAddressIsAllDNSLinkGroup(dst)) 213 if (errno == EHOSTDOWN || errno == ENETDOWN || errno == EHOSTUNREACH || errno == ENETUNREACH) return(mStatus_TransientErr); 214 215 if (MessageCount < 1000) 216 { 217 MessageCount++; 218 if (thisIntf) 219 LogMsg("mDNSPlatformSendUDP got error %d (%s) sending packet to %#a on interface %#a/%s/%d", 220 errno, strerror(errno), dst, &thisIntf->coreIntf.ip, thisIntf->intfName, thisIntf->index); 221 else 222 LogMsg("mDNSPlatformSendUDP got error %d (%s) sending packet to %#a", errno, strerror(errno), dst); 223 } 224 } 225 226 return PosixErrorToStatus(err); 227 } 228 229 // This routine is called when the main loop detects that data is available on a socket. 230 mDNSlocal void SocketDataReady(mDNS *const m, PosixNetworkInterface *intf, int skt) 231 { 232 mDNSAddr senderAddr, destAddr; 233 mDNSIPPort senderPort; 234 ssize_t packetLen; 235 DNSMessage packet; 236 struct my_in_pktinfo packetInfo; 237 struct sockaddr_storage from; 238 socklen_t fromLen; 239 int flags; 240 mDNSu8 ttl; 241 mDNSBool reject; 242 const mDNSInterfaceID InterfaceID = intf ? intf->coreIntf.InterfaceID : NULL; 243 244 assert(m != NULL); 245 assert(skt >= 0); 246 247 fromLen = sizeof(from); 248 flags = 0; 249 packetLen = recvfrom_flags(skt, &packet, sizeof(packet), &flags, (struct sockaddr *) &from, &fromLen, &packetInfo, &ttl); 250 251 if (packetLen >= 0) 252 { 253 SockAddrTomDNSAddr((struct sockaddr*)&from, &senderAddr, &senderPort); 254 SockAddrTomDNSAddr((struct sockaddr*)&packetInfo.ipi_addr, &destAddr, NULL); 255 256 // If we have broken IP_RECVDSTADDR functionality (so far 257 // I've only seen this on OpenBSD) then apply a hack to 258 // convince mDNS Core that this isn't a spoof packet. 259 // Basically what we do is check to see whether the 260 // packet arrived as a multicast and, if so, set its 261 // destAddr to the mDNS address. 262 // 263 // I must admit that I could just be doing something 264 // wrong on OpenBSD and hence triggering this problem 265 // but I'm at a loss as to how. 266 // 267 // If this platform doesn't have IP_PKTINFO or IP_RECVDSTADDR, then we have 268 // no way to tell the destination address or interface this packet arrived on, 269 // so all we can do is just assume it's a multicast 270 271 #if HAVE_BROKEN_RECVDSTADDR || (!defined(IP_PKTINFO) && !defined(IP_RECVDSTADDR)) 272 if ((destAddr.NotAnInteger == 0) && (flags & MSG_MCAST)) 273 { 274 destAddr.type = senderAddr.type; 275 if (senderAddr.type == mDNSAddrType_IPv4) destAddr.ip.v4 = AllDNSLinkGroup_v4.ip.v4; 276 else if (senderAddr.type == mDNSAddrType_IPv6) destAddr.ip.v6 = AllDNSLinkGroup_v6.ip.v6; 277 } 278 #endif 279 280 // We only accept the packet if the interface on which it came 281 // in matches the interface associated with this socket. 282 // We do this match by name or by index, depending on which 283 // information is available. recvfrom_flags sets the name 284 // to "" if the name isn't available, or the index to -1 285 // if the index is available. This accomodates the various 286 // different capabilities of our target platforms. 287 288 reject = mDNSfalse; 289 if (!intf) 290 { 291 // Ignore multicasts accidentally delivered to our unicast receiving socket 292 if (mDNSAddrIsDNSMulticast(&destAddr)) packetLen = -1; 293 } 294 else 295 { 296 if (packetInfo.ipi_ifname[0] != 0) reject = (strcmp(packetInfo.ipi_ifname, intf->intfName) != 0); 297 else if (packetInfo.ipi_ifindex != -1) reject = (packetInfo.ipi_ifindex != intf->index); 298 299 if (reject) 300 { 301 verbosedebugf("SocketDataReady ignored a packet from %#a to %#a on interface %s/%d expecting %#a/%s/%d/%d", 302 &senderAddr, &destAddr, packetInfo.ipi_ifname, packetInfo.ipi_ifindex, 303 &intf->coreIntf.ip, intf->intfName, intf->index, skt); 304 packetLen = -1; 305 num_pkts_rejected++; 306 if (num_pkts_rejected > (num_pkts_accepted + 1) * (num_registered_interfaces + 1) * 2) 307 { 308 fprintf(stderr, 309 "*** WARNING: Received %d packets; Accepted %d packets; Rejected %d packets because of interface mismatch\n", 310 num_pkts_accepted + num_pkts_rejected, num_pkts_accepted, num_pkts_rejected); 311 num_pkts_accepted = 0; 312 num_pkts_rejected = 0; 313 } 314 } 315 else 316 { 317 verbosedebugf("SocketDataReady got a packet from %#a to %#a on interface %#a/%s/%d/%d", 318 &senderAddr, &destAddr, &intf->coreIntf.ip, intf->intfName, intf->index, skt); 319 num_pkts_accepted++; 320 } 321 } 322 } 323 324 if (packetLen >= 0) 325 mDNSCoreReceive(m, &packet, (mDNSu8 *)&packet + packetLen, 326 &senderAddr, senderPort, &destAddr, MulticastDNSPort, InterfaceID); 327 } 328 329 mDNSexport TCPSocket *mDNSPlatformTCPSocket(mDNS * const m, TCPSocketFlags flags, mDNSIPPort * port) 330 { 331 (void)m; // Unused 332 (void)flags; // Unused 333 (void)port; // Unused 334 return NULL; 335 } 336 337 mDNSexport TCPSocket *mDNSPlatformTCPAccept(TCPSocketFlags flags, int sd) 338 { 339 (void)flags; // Unused 340 (void)sd; // Unused 341 return NULL; 342 } 343 344 mDNSexport int mDNSPlatformTCPGetFD(TCPSocket *sock) 345 { 346 (void)sock; // Unused 347 return -1; 348 } 349 350 mDNSexport mStatus mDNSPlatformTCPConnect(TCPSocket *sock, const mDNSAddr *dst, mDNSOpaque16 dstport, domainname *hostname, mDNSInterfaceID InterfaceID, 351 TCPConnectionCallback callback, void *context) 352 { 353 (void)sock; // Unused 354 (void)dst; // Unused 355 (void)dstport; // Unused 356 (void)hostname; // Unused 357 (void)InterfaceID; // Unused 358 (void)callback; // Unused 359 (void)context; // Unused 360 return(mStatus_UnsupportedErr); 361 } 362 363 mDNSexport void mDNSPlatformTCPCloseConnection(TCPSocket *sock) 364 { 365 (void)sock; // Unused 366 } 367 368 mDNSexport long mDNSPlatformReadTCP(TCPSocket *sock, void *buf, unsigned long buflen, mDNSBool * closed) 369 { 370 (void)sock; // Unused 371 (void)buf; // Unused 372 (void)buflen; // Unused 373 (void)closed; // Unused 374 return 0; 375 } 376 377 mDNSexport long mDNSPlatformWriteTCP(TCPSocket *sock, const char *msg, unsigned long len) 378 { 379 (void)sock; // Unused 380 (void)msg; // Unused 381 (void)len; // Unused 382 return 0; 383 } 384 385 mDNSexport UDPSocket *mDNSPlatformUDPSocket(mDNS * const m, mDNSIPPort port) 386 { 387 (void)m; // Unused 388 (void)port; // Unused 389 return NULL; 390 } 391 392 mDNSexport void mDNSPlatformUDPClose(UDPSocket *sock) 393 { 394 (void)sock; // Unused 395 } 396 397 mDNSexport void mDNSPlatformUpdateProxyList(mDNS *const m, const mDNSInterfaceID InterfaceID) 398 { 399 (void)m; // Unused 400 (void)InterfaceID; // Unused 401 } 402 403 mDNSexport void mDNSPlatformSendRawPacket(const void *const msg, const mDNSu8 *const end, mDNSInterfaceID InterfaceID) 404 { 405 (void)msg; // Unused 406 (void)end; // Unused 407 (void)InterfaceID; // Unused 408 } 409 410 mDNSexport void mDNSPlatformSetLocalAddressCacheEntry(mDNS *const m, const mDNSAddr *const tpa, const mDNSEthAddr *const tha, mDNSInterfaceID InterfaceID) 411 { 412 (void)m; // Unused 413 (void)tpa; // Unused 414 (void)tha; // Unused 415 (void)InterfaceID; // Unused 416 } 417 418 mDNSexport mStatus mDNSPlatformTLSSetupCerts(void) 419 { 420 return(mStatus_UnsupportedErr); 421 } 422 423 mDNSexport void mDNSPlatformTLSTearDownCerts(void) 424 { 425 } 426 427 mDNSexport void mDNSPlatformSetAllowSleep(mDNS *const m, mDNSBool allowSleep, const char *reason) 428 { 429 (void) m; 430 (void) allowSleep; 431 (void) reason; 432 } 433 434 #if COMPILER_LIKES_PRAGMA_MARK 435 #pragma mark - 436 #pragma mark - /etc/hosts support 437 #endif 438 439 mDNSexport void FreeEtcHosts(mDNS *const m, AuthRecord *const rr, mStatus result) 440 { 441 (void)m; // unused 442 (void)rr; 443 (void)result; 444 } 445 446 447 #if COMPILER_LIKES_PRAGMA_MARK 448 #pragma mark ***** DDNS Config Platform Functions 449 #endif 450 451 mDNSexport void mDNSPlatformSetDNSConfig(mDNS *const m, mDNSBool setservers, mDNSBool setsearch, domainname *const fqdn, DNameListElem **RegDomains, DNameListElem **BrowseDomains) 452 { 453 (void) m; 454 (void) setservers; 455 (void) fqdn; 456 (void) setsearch; 457 (void) RegDomains; 458 (void) BrowseDomains; 459 } 460 461 mDNSexport mStatus mDNSPlatformGetPrimaryInterface(mDNS * const m, mDNSAddr * v4, mDNSAddr * v6, mDNSAddr * router) 462 { 463 (void) m; 464 (void) v4; 465 (void) v6; 466 (void) router; 467 468 return mStatus_UnsupportedErr; 469 } 470 471 mDNSexport void mDNSPlatformDynDNSHostNameStatusChanged(const domainname *const dname, const mStatus status) 472 { 473 (void) dname; 474 (void) status; 475 } 476 477 #if COMPILER_LIKES_PRAGMA_MARK 478 #pragma mark ***** Init and Term 479 #endif 480 481 // This gets the current hostname, truncating it at the first dot if necessary 482 mDNSlocal void GetUserSpecifiedRFC1034ComputerName(domainlabel *const namelabel) 483 { 484 int len = 0; 485 #ifndef __ANDROID__ 486 gethostname((char *)(&namelabel->c[1]), MAX_DOMAIN_LABEL); 487 #else 488 // use an appropriate default label rather than the linux default of 'localhost' 489 strncpy(&namelabel->c[1], "Android", MAX_DOMAIN_LABEL); 490 #endif 491 while (len < MAX_DOMAIN_LABEL && namelabel->c[len+1] && namelabel->c[len+1] != '.') len++; 492 namelabel->c[0] = len; 493 } 494 495 // On OS X this gets the text of the field labelled "Computer Name" in the Sharing Prefs Control Panel 496 // Other platforms can either get the information from the appropriate place, 497 // or they can alternatively just require all registering services to provide an explicit name 498 mDNSlocal void GetUserSpecifiedFriendlyComputerName(domainlabel *const namelabel) 499 { 500 // On Unix we have no better name than the host name, so we just use that. 501 GetUserSpecifiedRFC1034ComputerName(namelabel); 502 } 503 504 mDNSexport int ParseDNSServers(mDNS *m, const char *filePath) 505 { 506 char line[256]; 507 char nameserver[16]; 508 char keyword[10]; 509 int numOfServers = 0; 510 FILE *fp = fopen(filePath, "r"); 511 if (fp == NULL) return -1; 512 while (fgets(line,sizeof(line),fp)) 513 { 514 struct in_addr ina; 515 line[255]='\0'; // just to be safe 516 if (sscanf(line,"%10s %15s", keyword, nameserver) != 2) continue; // it will skip whitespaces 517 if (strncasecmp(keyword,"nameserver",10)) continue; 518 if (inet_aton(nameserver, (struct in_addr *)&ina) != 0) 519 { 520 mDNSAddr DNSAddr; 521 DNSAddr.type = mDNSAddrType_IPv4; 522 DNSAddr.ip.v4.NotAnInteger = ina.s_addr; 523 mDNS_AddDNSServer(m, NULL, mDNSInterface_Any, &DNSAddr, UnicastDNSPort, mDNSfalse, 0); 524 numOfServers++; 525 } 526 } 527 // __ANDROID__ : if fp was opened, it needs to be closed 528 int fp_closed = fclose(fp); 529 assert(fp_closed == 0); 530 return (numOfServers > 0) ? 0 : -1; 531 } 532 533 // Searches the interface list looking for the named interface. 534 // Returns a pointer to if it found, or NULL otherwise. 535 mDNSlocal PosixNetworkInterface *SearchForInterfaceByName(mDNS *const m, const char *intfName) 536 { 537 PosixNetworkInterface *intf; 538 539 assert(m != NULL); 540 assert(intfName != NULL); 541 542 intf = (PosixNetworkInterface*)(m->HostInterfaces); 543 while ((intf != NULL) && (strcmp(intf->intfName, intfName) != 0)) 544 intf = (PosixNetworkInterface *)(intf->coreIntf.next); 545 546 return intf; 547 } 548 549 mDNSexport mDNSInterfaceID mDNSPlatformInterfaceIDfromInterfaceIndex(mDNS *const m, mDNSu32 index) 550 { 551 PosixNetworkInterface *intf; 552 553 assert(m != NULL); 554 555 if (index == kDNSServiceInterfaceIndexLocalOnly) return(mDNSInterface_LocalOnly); 556 if (index == kDNSServiceInterfaceIndexP2P ) return(mDNSInterface_P2P); 557 if (index == kDNSServiceInterfaceIndexAny ) return(mDNSInterface_Any); 558 559 intf = (PosixNetworkInterface*)(m->HostInterfaces); 560 while ((intf != NULL) && (mDNSu32) intf->index != index) 561 intf = (PosixNetworkInterface *)(intf->coreIntf.next); 562 563 return (mDNSInterfaceID) intf; 564 } 565 566 mDNSexport mDNSu32 mDNSPlatformInterfaceIndexfromInterfaceID(mDNS *const m, mDNSInterfaceID id, mDNSBool suppressNetworkChange) 567 { 568 PosixNetworkInterface *intf; 569 (void) suppressNetworkChange; // Unused 570 571 assert(m != NULL); 572 573 if (id == mDNSInterface_LocalOnly) return(kDNSServiceInterfaceIndexLocalOnly); 574 if (id == mDNSInterface_P2P ) return(kDNSServiceInterfaceIndexP2P); 575 if (id == mDNSInterface_Any ) return(kDNSServiceInterfaceIndexAny); 576 577 intf = (PosixNetworkInterface*)(m->HostInterfaces); 578 while ((intf != NULL) && (mDNSInterfaceID) intf != id) 579 intf = (PosixNetworkInterface *)(intf->coreIntf.next); 580 581 return intf ? intf->index : 0; 582 } 583 584 // Frees the specified PosixNetworkInterface structure. The underlying 585 // interface must have already been deregistered with the mDNS core. 586 mDNSlocal void FreePosixNetworkInterface(PosixNetworkInterface *intf) 587 { 588 assert(intf != NULL); 589 if (intf->intfName != NULL) free((void *)intf->intfName); 590 if (intf->multicastSocket4 != -1) 591 { 592 int ipv4_closed = close(intf->multicastSocket4); 593 assert(ipv4_closed == 0); 594 } 595 #if HAVE_IPV6 596 if (intf->multicastSocket6 != -1) 597 { 598 int ipv6_closed = close(intf->multicastSocket6); 599 assert(ipv6_closed == 0); 600 } 601 #endif 602 free(intf); 603 } 604 605 // Grab the first interface, deregister it, free it, and repeat until done. 606 mDNSlocal void ClearInterfaceList(mDNS *const m) 607 { 608 assert(m != NULL); 609 610 while (m->HostInterfaces) 611 { 612 PosixNetworkInterface *intf = (PosixNetworkInterface*)(m->HostInterfaces); 613 mDNS_DeregisterInterface(m, &intf->coreIntf, mDNSfalse); 614 if (gMDNSPlatformPosixVerboseLevel > 0) fprintf(stderr, "Deregistered interface %s\n", intf->intfName); 615 FreePosixNetworkInterface(intf); 616 } 617 num_registered_interfaces = 0; 618 num_pkts_accepted = 0; 619 num_pkts_rejected = 0; 620 } 621 622 // Sets up a send/receive socket. 623 // If mDNSIPPort port is non-zero, then it's a multicast socket on the specified interface 624 // If mDNSIPPort port is zero, then it's a randomly assigned port number, used for sending unicast queries 625 mDNSlocal int SetupSocket(struct sockaddr *intfAddr, mDNSIPPort port, int interfaceIndex, int *sktPtr) 626 { 627 int err = 0; 628 static const int kOn = 1; 629 static const int kIntTwoFiveFive = 255; 630 static const unsigned char kByteTwoFiveFive = 255; 631 const mDNSBool JoinMulticastGroup = (port.NotAnInteger != 0); 632 633 (void) interfaceIndex; // This parameter unused on plaforms that don't have IPv6 634 assert(intfAddr != NULL); 635 assert(sktPtr != NULL); 636 assert(*sktPtr == -1); 637 638 // Open the socket... 639 if (intfAddr->sa_family == AF_INET) *sktPtr = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); 640 #if HAVE_IPV6 641 else if (intfAddr->sa_family == AF_INET6) *sktPtr = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP); 642 #endif 643 else return EINVAL; 644 645 if (*sktPtr < 0) { err = errno; perror((intfAddr->sa_family == AF_INET) ? "socket AF_INET" : "socket AF_INET6"); } 646 647 // ... with a shared UDP port, if it's for multicast receiving 648 if (err == 0 && port.NotAnInteger) 649 { 650 #if defined(SO_REUSEPORT) 651 err = setsockopt(*sktPtr, SOL_SOCKET, SO_REUSEPORT, &kOn, sizeof(kOn)); 652 #elif defined(SO_REUSEADDR) 653 err = setsockopt(*sktPtr, SOL_SOCKET, SO_REUSEADDR, &kOn, sizeof(kOn)); 654 #else 655 #error This platform has no way to avoid address busy errors on multicast. 656 #endif 657 if (err < 0) { err = errno; perror("setsockopt - SO_REUSExxxx"); } 658 } 659 660 // We want to receive destination addresses and interface identifiers. 661 if (intfAddr->sa_family == AF_INET) 662 { 663 struct ip_mreq imr; 664 struct sockaddr_in bindAddr; 665 if (err == 0) 666 { 667 #if defined(IP_PKTINFO) // Linux 668 err = setsockopt(*sktPtr, IPPROTO_IP, IP_PKTINFO, &kOn, sizeof(kOn)); 669 if (err < 0) { err = errno; perror("setsockopt - IP_PKTINFO"); } 670 #elif defined(IP_RECVDSTADDR) || defined(IP_RECVIF) // BSD and Solaris 671 #if defined(IP_RECVDSTADDR) 672 err = setsockopt(*sktPtr, IPPROTO_IP, IP_RECVDSTADDR, &kOn, sizeof(kOn)); 673 if (err < 0) { err = errno; perror("setsockopt - IP_RECVDSTADDR"); } 674 #endif 675 #if defined(IP_RECVIF) 676 if (err == 0) 677 { 678 err = setsockopt(*sktPtr, IPPROTO_IP, IP_RECVIF, &kOn, sizeof(kOn)); 679 if (err < 0) { err = errno; perror("setsockopt - IP_RECVIF"); } 680 } 681 #endif 682 #else 683 #warning This platform has no way to get the destination interface information -- will only work for single-homed hosts 684 #endif 685 } 686 #if defined(IP_RECVTTL) // Linux 687 if (err == 0) 688 { 689 setsockopt(*sktPtr, IPPROTO_IP, IP_RECVTTL, &kOn, sizeof(kOn)); 690 // We no longer depend on being able to get the received TTL, so don't worry if the option fails 691 } 692 #endif 693 694 // Add multicast group membership on this interface 695 if (err == 0 && JoinMulticastGroup) 696 { 697 imr.imr_multiaddr.s_addr = AllDNSLinkGroup_v4.ip.v4.NotAnInteger; 698 imr.imr_interface = ((struct sockaddr_in*)intfAddr)->sin_addr; 699 err = setsockopt(*sktPtr, IPPROTO_IP, IP_ADD_MEMBERSHIP, &imr, sizeof(imr)); 700 if (err < 0) { err = errno; perror("setsockopt - IP_ADD_MEMBERSHIP"); } 701 } 702 703 // Specify outgoing interface too 704 if (err == 0 && JoinMulticastGroup) 705 { 706 err = setsockopt(*sktPtr, IPPROTO_IP, IP_MULTICAST_IF, &((struct sockaddr_in*)intfAddr)->sin_addr, sizeof(struct in_addr)); 707 if (err < 0) { err = errno; perror("setsockopt - IP_MULTICAST_IF"); } 708 } 709 710 // Per the mDNS spec, send unicast packets with TTL 255 711 if (err == 0) 712 { 713 err = setsockopt(*sktPtr, IPPROTO_IP, IP_TTL, &kIntTwoFiveFive, sizeof(kIntTwoFiveFive)); 714 if (err < 0) { err = errno; perror("setsockopt - IP_TTL"); } 715 } 716 717 // and multicast packets with TTL 255 too 718 // There's some debate as to whether IP_MULTICAST_TTL is an int or a byte so we just try both. 719 if (err == 0) 720 { 721 err = setsockopt(*sktPtr, IPPROTO_IP, IP_MULTICAST_TTL, &kByteTwoFiveFive, sizeof(kByteTwoFiveFive)); 722 if (err < 0 && errno == EINVAL) 723 err = setsockopt(*sktPtr, IPPROTO_IP, IP_MULTICAST_TTL, &kIntTwoFiveFive, sizeof(kIntTwoFiveFive)); 724 if (err < 0) { err = errno; perror("setsockopt - IP_MULTICAST_TTL"); } 725 } 726 727 // And start listening for packets 728 if (err == 0) 729 { 730 bindAddr.sin_family = AF_INET; 731 bindAddr.sin_port = port.NotAnInteger; 732 bindAddr.sin_addr.s_addr = INADDR_ANY; // Want to receive multicasts AND unicasts on this socket 733 err = bind(*sktPtr, (struct sockaddr *) &bindAddr, sizeof(bindAddr)); 734 if (err < 0) { err = errno; perror("bind"); fflush(stderr); } 735 } 736 } // endif (intfAddr->sa_family == AF_INET) 737 738 #if HAVE_IPV6 739 else if (intfAddr->sa_family == AF_INET6) 740 { 741 struct ipv6_mreq imr6; 742 struct sockaddr_in6 bindAddr6; 743 #if defined(IPV6_PKTINFO) 744 if (err == 0) 745 { 746 err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_2292_PKTINFO, &kOn, sizeof(kOn)); 747 if (err < 0) { err = errno; perror("setsockopt - IPV6_PKTINFO"); } 748 } 749 #else 750 #warning This platform has no way to get the destination interface information for IPv6 -- will only work for single-homed hosts 751 #endif 752 #if defined(IPV6_HOPLIMIT) 753 if (err == 0) 754 { 755 err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_2292_HOPLIMIT, &kOn, sizeof(kOn)); 756 if (err < 0) { err = errno; perror("setsockopt - IPV6_HOPLIMIT"); } 757 } 758 #endif 759 760 // Add multicast group membership on this interface 761 if (err == 0 && JoinMulticastGroup) 762 { 763 imr6.ipv6mr_multiaddr = *(const struct in6_addr*)&AllDNSLinkGroup_v6.ip.v6; 764 imr6.ipv6mr_interface = interfaceIndex; 765 //LogMsg("Joining %.16a on %d", &imr6.ipv6mr_multiaddr, imr6.ipv6mr_interface); 766 err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_JOIN_GROUP, &imr6, sizeof(imr6)); 767 if (err < 0) 768 { 769 err = errno; 770 verbosedebugf("IPV6_JOIN_GROUP %.16a on %d failed.\n", &imr6.ipv6mr_multiaddr, imr6.ipv6mr_interface); 771 perror("setsockopt - IPV6_JOIN_GROUP"); 772 } 773 } 774 775 // Specify outgoing interface too 776 if (err == 0 && JoinMulticastGroup) 777 { 778 u_int multicast_if = interfaceIndex; 779 err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_MULTICAST_IF, &multicast_if, sizeof(multicast_if)); 780 if (err < 0) { err = errno; perror("setsockopt - IPV6_MULTICAST_IF"); } 781 } 782 783 // We want to receive only IPv6 packets on this socket. 784 // Without this option, we may get IPv4 addresses as mapped addresses. 785 if (err == 0) 786 { 787 err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_V6ONLY, &kOn, sizeof(kOn)); 788 if (err < 0) { err = errno; perror("setsockopt - IPV6_V6ONLY"); } 789 } 790 791 // Per the mDNS spec, send unicast packets with TTL 255 792 if (err == 0) 793 { 794 err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &kIntTwoFiveFive, sizeof(kIntTwoFiveFive)); 795 if (err < 0) { err = errno; perror("setsockopt - IPV6_UNICAST_HOPS"); } 796 } 797 798 // and multicast packets with TTL 255 too 799 // There's some debate as to whether IPV6_MULTICAST_HOPS is an int or a byte so we just try both. 800 if (err == 0) 801 { 802 err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &kByteTwoFiveFive, sizeof(kByteTwoFiveFive)); 803 if (err < 0 && errno == EINVAL) 804 err = setsockopt(*sktPtr, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &kIntTwoFiveFive, sizeof(kIntTwoFiveFive)); 805 if (err < 0) { err = errno; perror("setsockopt - IPV6_MULTICAST_HOPS"); } 806 } 807 808 // And start listening for packets 809 if (err == 0) 810 { 811 mDNSPlatformMemZero(&bindAddr6, sizeof(bindAddr6)); 812 #ifndef NOT_HAVE_SA_LEN 813 bindAddr6.sin6_len = sizeof(bindAddr6); 814 #endif 815 bindAddr6.sin6_family = AF_INET6; 816 bindAddr6.sin6_port = port.NotAnInteger; 817 bindAddr6.sin6_flowinfo = 0; 818 bindAddr6.sin6_addr = in6addr_any; // Want to receive multicasts AND unicasts on this socket 819 bindAddr6.sin6_scope_id = 0; 820 err = bind(*sktPtr, (struct sockaddr *) &bindAddr6, sizeof(bindAddr6)); 821 if (err < 0) { err = errno; perror("bind"); fflush(stderr); } 822 } 823 } // endif (intfAddr->sa_family == AF_INET6) 824 #endif 825 826 // Set the socket to non-blocking. 827 if (err == 0) 828 { 829 err = fcntl(*sktPtr, F_GETFL, 0); 830 if (err < 0) err = errno; 831 else 832 { 833 err = fcntl(*sktPtr, F_SETFL, err | O_NONBLOCK); 834 if (err < 0) err = errno; 835 } 836 } 837 838 // Clean up 839 if (err != 0 && *sktPtr != -1) 840 { 841 int sktClosed = close(*sktPtr); 842 assert(sktClosed == 0); 843 *sktPtr = -1; 844 } 845 assert((err == 0) == (*sktPtr != -1)); 846 return err; 847 } 848 849 // Creates a PosixNetworkInterface for the interface whose IP address is 850 // intfAddr and whose name is intfName and registers it with mDNS core. 851 mDNSlocal int SetupOneInterface(mDNS *const m, struct sockaddr *intfAddr, struct sockaddr *intfMask, const char *intfName, int intfIndex) 852 { 853 int err = 0; 854 PosixNetworkInterface *intf; 855 PosixNetworkInterface *alias = NULL; 856 857 assert(m != NULL); 858 assert(intfAddr != NULL); 859 assert(intfName != NULL); 860 assert(intfMask != NULL); 861 862 // Allocate the interface structure itself. 863 intf = (PosixNetworkInterface*)malloc(sizeof(*intf)); 864 if (intf == NULL) { assert(0); err = ENOMEM; } 865 866 // And make a copy of the intfName. 867 if (err == 0) 868 { 869 intf->intfName = strdup(intfName); 870 if (intf->intfName == NULL) { assert(0); err = ENOMEM; } 871 } 872 873 if (err == 0) 874 { 875 // Set up the fields required by the mDNS core. 876 SockAddrTomDNSAddr(intfAddr, &intf->coreIntf.ip, NULL); 877 SockAddrTomDNSAddr(intfMask, &intf->coreIntf.mask, NULL); 878 879 //LogMsg("SetupOneInterface: %#a %#a", &intf->coreIntf.ip, &intf->coreIntf.mask); 880 strncpy(intf->coreIntf.ifname, intfName, sizeof(intf->coreIntf.ifname)); 881 intf->coreIntf.ifname[sizeof(intf->coreIntf.ifname)-1] = 0; 882 intf->coreIntf.Advertise = m->AdvertiseLocalAddresses; 883 intf->coreIntf.McastTxRx = mDNStrue; 884 885 // Set up the extra fields in PosixNetworkInterface. 886 assert(intf->intfName != NULL); // intf->intfName already set up above 887 intf->index = intfIndex; 888 intf->multicastSocket4 = -1; 889 #if HAVE_IPV6 890 intf->multicastSocket6 = -1; 891 #endif 892 alias = SearchForInterfaceByName(m, intf->intfName); 893 if (alias == NULL) alias = intf; 894 intf->coreIntf.InterfaceID = (mDNSInterfaceID)alias; 895 896 if (alias != intf) 897 debugf("SetupOneInterface: %s %#a is an alias of %#a", intfName, &intf->coreIntf.ip, &alias->coreIntf.ip); 898 } 899 900 // Set up the multicast socket 901 if (err == 0) 902 { 903 if (alias->multicastSocket4 == -1 && intfAddr->sa_family == AF_INET) 904 err = SetupSocket(intfAddr, MulticastDNSPort, intf->index, &alias->multicastSocket4); 905 #if HAVE_IPV6 906 else if (alias->multicastSocket6 == -1 && intfAddr->sa_family == AF_INET6) 907 err = SetupSocket(intfAddr, MulticastDNSPort, intf->index, &alias->multicastSocket6); 908 #endif 909 } 910 911 // The interface is all ready to go, let's register it with the mDNS core. 912 if (err == 0) 913 err = mDNS_RegisterInterface(m, &intf->coreIntf, mDNSfalse); 914 915 // Clean up. 916 if (err == 0) 917 { 918 num_registered_interfaces++; 919 debugf("SetupOneInterface: %s %#a Registered", intf->intfName, &intf->coreIntf.ip); 920 if (gMDNSPlatformPosixVerboseLevel > 0) 921 fprintf(stderr, "Registered interface %s\n", intf->intfName); 922 } 923 else 924 { 925 // Use intfName instead of intf->intfName in the next line to avoid dereferencing NULL. 926 debugf("SetupOneInterface: %s %#a failed to register %d", intfName, &intf->coreIntf.ip, err); 927 if (intf) { FreePosixNetworkInterface(intf); intf = NULL; } 928 } 929 930 assert((err == 0) == (intf != NULL)); 931 932 return err; 933 } 934 935 // Call get_ifi_info() to obtain a list of active interfaces and call SetupOneInterface() on each one. 936 mDNSlocal int SetupInterfaceList(mDNS *const m) 937 { 938 mDNSBool foundav4 = mDNSfalse; 939 int err = 0; 940 struct ifi_info *intfList = get_ifi_info(AF_INET, mDNStrue); 941 struct ifi_info *firstLoopback = NULL; 942 943 assert(m != NULL); 944 debugf("SetupInterfaceList"); 945 946 if (intfList == NULL) err = ENOENT; 947 948 #if HAVE_IPV6 949 if (err == 0) /* Link the IPv6 list to the end of the IPv4 list */ 950 { 951 struct ifi_info **p = &intfList; 952 while (*p) p = &(*p)->ifi_next; 953 *p = get_ifi_info(AF_INET6, mDNStrue); 954 } 955 #endif 956 957 if (err == 0) 958 { 959 struct ifi_info *i = intfList; 960 while (i) 961 { 962 if ( ((i->ifi_addr->sa_family == AF_INET) 963 #if HAVE_IPV6 964 || (i->ifi_addr->sa_family == AF_INET6) 965 #endif 966 ) && (i->ifi_flags & IFF_UP) && !(i->ifi_flags & IFF_POINTOPOINT)) 967 { 968 if (i->ifi_flags & IFF_LOOPBACK) 969 { 970 if (firstLoopback == NULL) 971 firstLoopback = i; 972 } 973 else 974 { 975 if (SetupOneInterface(m, i->ifi_addr, i->ifi_netmask, i->ifi_name, i->ifi_index) == 0) 976 if (i->ifi_addr->sa_family == AF_INET) 977 foundav4 = mDNStrue; 978 } 979 } 980 i = i->ifi_next; 981 } 982 983 // If we found no normal interfaces but we did find a loopback interface, register the 984 // loopback interface. This allows self-discovery if no interfaces are configured. 985 // Temporary workaround: Multicast loopback on IPv6 interfaces appears not to work. 986 // In the interim, we skip loopback interface only if we found at least one v4 interface to use 987 // if ((m->HostInterfaces == NULL) && (firstLoopback != NULL)) 988 if (!foundav4 && firstLoopback) 989 (void) SetupOneInterface(m, firstLoopback->ifi_addr, firstLoopback->ifi_netmask, firstLoopback->ifi_name, firstLoopback->ifi_index); 990 } 991 992 // Clean up. 993 if (intfList != NULL) free_ifi_info(intfList); 994 return err; 995 } 996 997 #if USES_NETLINK 998 999 // See <http://www.faqs.org/rfcs/rfc3549.html> for a description of NetLink 1000 1001 // Open a socket that will receive interface change notifications 1002 mDNSlocal mStatus OpenIfNotifySocket(int *pFD) 1003 { 1004 mStatus err = mStatus_NoError; 1005 struct sockaddr_nl snl; 1006 int sock; 1007 int ret; 1008 1009 sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); 1010 if (sock < 0) 1011 return errno; 1012 1013 // Configure read to be non-blocking because inbound msg size is not known in advance 1014 (void) fcntl(sock, F_SETFL, O_NONBLOCK); 1015 1016 /* Subscribe the socket to Link & IP addr notifications. */ 1017 mDNSPlatformMemZero(&snl, sizeof snl); 1018 snl.nl_family = AF_NETLINK; 1019 snl.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR; 1020 ret = bind(sock, (struct sockaddr *) &snl, sizeof snl); 1021 if (0 == ret) 1022 *pFD = sock; 1023 else 1024 err = errno; 1025 1026 return err; 1027 } 1028 1029 #if MDNS_DEBUGMSGS 1030 mDNSlocal void PrintNetLinkMsg(const struct nlmsghdr *pNLMsg) 1031 { 1032 const char *kNLMsgTypes[] = { "", "NLMSG_NOOP", "NLMSG_ERROR", "NLMSG_DONE", "NLMSG_OVERRUN" }; 1033 const char *kNLRtMsgTypes[] = { "RTM_NEWLINK", "RTM_DELLINK", "RTM_GETLINK", "RTM_NEWADDR", "RTM_DELADDR", "RTM_GETADDR" }; 1034 1035 printf("nlmsghdr len=%d, type=%s, flags=0x%x\n", pNLMsg->nlmsg_len, 1036 pNLMsg->nlmsg_type < RTM_BASE ? kNLMsgTypes[pNLMsg->nlmsg_type] : kNLRtMsgTypes[pNLMsg->nlmsg_type - RTM_BASE], 1037 pNLMsg->nlmsg_flags); 1038 1039 if (RTM_NEWLINK <= pNLMsg->nlmsg_type && pNLMsg->nlmsg_type <= RTM_GETLINK) 1040 { 1041 struct ifinfomsg *pIfInfo = (struct ifinfomsg*) NLMSG_DATA(pNLMsg); 1042 printf("ifinfomsg family=%d, type=%d, index=%d, flags=0x%x, change=0x%x\n", pIfInfo->ifi_family, 1043 pIfInfo->ifi_type, pIfInfo->ifi_index, pIfInfo->ifi_flags, pIfInfo->ifi_change); 1044 1045 } 1046 else if (RTM_NEWADDR <= pNLMsg->nlmsg_type && pNLMsg->nlmsg_type <= RTM_GETADDR) 1047 { 1048 struct ifaddrmsg *pIfAddr = (struct ifaddrmsg*) NLMSG_DATA(pNLMsg); 1049 printf("ifaddrmsg family=%d, index=%d, flags=0x%x\n", pIfAddr->ifa_family, 1050 pIfAddr->ifa_index, pIfAddr->ifa_flags); 1051 } 1052 printf("\n"); 1053 } 1054 #endif 1055 1056 mDNSlocal mDNSu32 ProcessRoutingNotification(int sd) 1057 // Read through the messages on sd and if any indicate that any interface records should 1058 // be torn down and rebuilt, return affected indices as a bitmask. Otherwise return 0. 1059 { 1060 ssize_t readCount; 1061 char buff[4096]; 1062 struct nlmsghdr *pNLMsg = (struct nlmsghdr*) buff; 1063 mDNSu32 result = 0; 1064 1065 // The structure here is more complex than it really ought to be because, 1066 // unfortunately, there's no good way to size a buffer in advance large 1067 // enough to hold all pending data and so avoid message fragmentation. 1068 // (Note that FIONREAD is not supported on AF_NETLINK.) 1069 1070 readCount = read(sd, buff, sizeof buff); 1071 while (1) 1072 { 1073 // Make sure we've got an entire nlmsghdr in the buffer, and payload, too. 1074 // If not, discard already-processed messages in buffer and read more data. 1075 if (((char*) &pNLMsg[1] > (buff + readCount)) || // i.e. *pNLMsg extends off end of buffer 1076 ((char*) pNLMsg + pNLMsg->nlmsg_len > (buff + readCount))) 1077 { 1078 if (buff < (char*) pNLMsg) // we have space to shuffle 1079 { 1080 // discard processed data 1081 readCount -= ((char*) pNLMsg - buff); 1082 memmove(buff, pNLMsg, readCount); 1083 pNLMsg = (struct nlmsghdr*) buff; 1084 1085 // read more data 1086 readCount += read(sd, buff + readCount, sizeof buff - readCount); 1087 continue; // spin around and revalidate with new readCount 1088 } 1089 else 1090 break; // Otherwise message does not fit in buffer 1091 } 1092 1093 #if MDNS_DEBUGMSGS 1094 PrintNetLinkMsg(pNLMsg); 1095 #endif 1096 1097 // Process the NetLink message 1098 if (pNLMsg->nlmsg_type == RTM_GETLINK || pNLMsg->nlmsg_type == RTM_NEWLINK) 1099 result |= 1 << ((struct ifinfomsg*) NLMSG_DATA(pNLMsg))->ifi_index; 1100 else if (pNLMsg->nlmsg_type == RTM_DELADDR || pNLMsg->nlmsg_type == RTM_NEWADDR) 1101 result |= 1 << ((struct ifaddrmsg*) NLMSG_DATA(pNLMsg))->ifa_index; 1102 1103 // Advance pNLMsg to the next message in the buffer 1104 if ((pNLMsg->nlmsg_flags & NLM_F_MULTI) != 0 && pNLMsg->nlmsg_type != NLMSG_DONE) 1105 { 1106 ssize_t len = readCount - ((char*)pNLMsg - buff); 1107 pNLMsg = NLMSG_NEXT(pNLMsg, len); 1108 } 1109 else 1110 break; // all done! 1111 } 1112 1113 return result; 1114 } 1115 1116 #else // USES_NETLINK 1117 1118 // Open a socket that will receive interface change notifications 1119 mDNSlocal mStatus OpenIfNotifySocket(int *pFD) 1120 { 1121 *pFD = socket(AF_ROUTE, SOCK_RAW, 0); 1122 1123 if (*pFD < 0) 1124 return mStatus_UnknownErr; 1125 1126 // Configure read to be non-blocking because inbound msg size is not known in advance 1127 (void) fcntl(*pFD, F_SETFL, O_NONBLOCK); 1128 1129 return mStatus_NoError; 1130 } 1131 1132 #if MDNS_DEBUGMSGS 1133 mDNSlocal void PrintRoutingSocketMsg(const struct ifa_msghdr *pRSMsg) 1134 { 1135 const char *kRSMsgTypes[] = { "", "RTM_ADD", "RTM_DELETE", "RTM_CHANGE", "RTM_GET", "RTM_LOSING", 1136 "RTM_REDIRECT", "RTM_MISS", "RTM_LOCK", "RTM_OLDADD", "RTM_OLDDEL", "RTM_RESOLVE", 1137 "RTM_NEWADDR", "RTM_DELADDR", "RTM_IFINFO", "RTM_NEWMADDR", "RTM_DELMADDR" }; 1138 1139 int index = pRSMsg->ifam_type == RTM_IFINFO ? ((struct if_msghdr*) pRSMsg)->ifm_index : pRSMsg->ifam_index; 1140 1141 printf("ifa_msghdr len=%d, type=%s, index=%d\n", pRSMsg->ifam_msglen, kRSMsgTypes[pRSMsg->ifam_type], index); 1142 } 1143 #endif 1144 1145 mDNSlocal mDNSu32 ProcessRoutingNotification(int sd) 1146 // Read through the messages on sd and if any indicate that any interface records should 1147 // be torn down and rebuilt, return affected indices as a bitmask. Otherwise return 0. 1148 { 1149 ssize_t readCount; 1150 char buff[4096]; 1151 struct ifa_msghdr *pRSMsg = (struct ifa_msghdr*) buff; 1152 mDNSu32 result = 0; 1153 1154 readCount = read(sd, buff, sizeof buff); 1155 if (readCount < (ssize_t) sizeof(struct ifa_msghdr)) 1156 return mStatus_UnsupportedErr; // cannot decipher message 1157 1158 #if MDNS_DEBUGMSGS 1159 PrintRoutingSocketMsg(pRSMsg); 1160 #endif 1161 1162 // Process the message 1163 if (pRSMsg->ifam_type == RTM_NEWADDR || pRSMsg->ifam_type == RTM_DELADDR || 1164 pRSMsg->ifam_type == RTM_IFINFO) 1165 { 1166 if (pRSMsg->ifam_type == RTM_IFINFO) 1167 result |= 1 << ((struct if_msghdr*) pRSMsg)->ifm_index; 1168 else 1169 result |= 1 << pRSMsg->ifam_index; 1170 } 1171 1172 return result; 1173 } 1174 1175 #endif // USES_NETLINK 1176 1177 // Called when data appears on interface change notification socket 1178 mDNSlocal void InterfaceChangeCallback(int fd, short filter, void *context) 1179 { 1180 IfChangeRec *pChgRec = (IfChangeRec*) context; 1181 fd_set readFDs; 1182 mDNSu32 changedInterfaces = 0; 1183 struct timeval zeroTimeout = { 0, 0 }; 1184 1185 (void)fd; // Unused 1186 (void)filter; // Unused 1187 1188 FD_ZERO(&readFDs); 1189 FD_SET(pChgRec->NotifySD, &readFDs); 1190 1191 do 1192 { 1193 changedInterfaces |= ProcessRoutingNotification(pChgRec->NotifySD); 1194 } 1195 while (0 < select(pChgRec->NotifySD + 1, &readFDs, (fd_set*) NULL, (fd_set*) NULL, &zeroTimeout)); 1196 1197 // Currently we rebuild the entire interface list whenever any interface change is 1198 // detected. If this ever proves to be a performance issue in a multi-homed 1199 // configuration, more care should be paid to changedInterfaces. 1200 if (changedInterfaces) 1201 mDNSPlatformPosixRefreshInterfaceList(pChgRec->mDNS); 1202 } 1203 1204 // Register with either a Routing Socket or RtNetLink to listen for interface changes. 1205 mDNSlocal mStatus WatchForInterfaceChange(mDNS *const m) 1206 { 1207 mStatus err; 1208 IfChangeRec *pChgRec; 1209 1210 pChgRec = (IfChangeRec*) mDNSPlatformMemAllocate(sizeof *pChgRec); 1211 if (pChgRec == NULL) 1212 return mStatus_NoMemoryErr; 1213 1214 pChgRec->mDNS = m; 1215 err = OpenIfNotifySocket(&pChgRec->NotifySD); 1216 if (err == 0) 1217 err = mDNSPosixAddFDToEventLoop(pChgRec->NotifySD, InterfaceChangeCallback, pChgRec); 1218 1219 return err; 1220 } 1221 1222 // Test to see if we're the first client running on UDP port 5353, by trying to bind to 5353 without using SO_REUSEPORT. 1223 // If we fail, someone else got here first. That's not a big problem; we can share the port for multicast responses -- 1224 // we just need to be aware that we shouldn't expect to successfully receive unicast UDP responses. 1225 mDNSlocal mDNSBool mDNSPlatformInit_CanReceiveUnicast(void) 1226 { 1227 int err; 1228 int s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); 1229 struct sockaddr_in s5353; 1230 s5353.sin_family = AF_INET; 1231 s5353.sin_port = MulticastDNSPort.NotAnInteger; 1232 s5353.sin_addr.s_addr = 0; 1233 err = bind(s, (struct sockaddr *)&s5353, sizeof(s5353)); 1234 close(s); 1235 if (err) debugf("No unicast UDP responses"); 1236 else debugf("Unicast UDP responses okay"); 1237 return(err == 0); 1238 } 1239 1240 // mDNS core calls this routine to initialise the platform-specific data. 1241 mDNSexport mStatus mDNSPlatformInit(mDNS *const m) 1242 { 1243 int err = 0; 1244 struct sockaddr sa; 1245 assert(m != NULL); 1246 1247 if (mDNSPlatformInit_CanReceiveUnicast()) m->CanReceiveUnicastOn5353 = mDNStrue; 1248 1249 // Tell mDNS core the names of this machine. 1250 1251 // Set up the nice label 1252 m->nicelabel.c[0] = 0; 1253 GetUserSpecifiedFriendlyComputerName(&m->nicelabel); 1254 if (m->nicelabel.c[0] == 0) MakeDomainLabelFromLiteralString(&m->nicelabel, "Computer"); 1255 1256 // Set up the RFC 1034-compliant label 1257 m->hostlabel.c[0] = 0; 1258 GetUserSpecifiedRFC1034ComputerName(&m->hostlabel); 1259 if (m->hostlabel.c[0] == 0) MakeDomainLabelFromLiteralString(&m->hostlabel, "Computer"); 1260 1261 mDNS_SetFQDN(m); 1262 1263 sa.sa_family = AF_INET; 1264 m->p->unicastSocket4 = -1; 1265 if (err == mStatus_NoError) err = SetupSocket(&sa, zeroIPPort, 0, &m->p->unicastSocket4); 1266 #if HAVE_IPV6 1267 sa.sa_family = AF_INET6; 1268 m->p->unicastSocket6 = -1; 1269 if (err == mStatus_NoError) err = SetupSocket(&sa, zeroIPPort, 0, &m->p->unicastSocket6); 1270 #endif 1271 1272 // Tell mDNS core about the network interfaces on this machine. 1273 if (err == mStatus_NoError) err = SetupInterfaceList(m); 1274 1275 // Tell mDNS core about DNS Servers 1276 mDNS_Lock(m); 1277 if (err == mStatus_NoError) ParseDNSServers(m, uDNS_SERVERS_FILE); 1278 mDNS_Unlock(m); 1279 1280 if (err == mStatus_NoError) 1281 { 1282 err = WatchForInterfaceChange(m); 1283 // Failure to observe interface changes is non-fatal. 1284 if (err != mStatus_NoError) 1285 { 1286 fprintf(stderr, "mDNS(%d) WARNING: Unable to detect interface changes (%d).\n", getpid(), err); 1287 err = mStatus_NoError; 1288 } 1289 } 1290 1291 // We don't do asynchronous initialization on the Posix platform, so by the time 1292 // we get here the setup will already have succeeded or failed. If it succeeded, 1293 // we should just call mDNSCoreInitComplete() immediately. 1294 if (err == mStatus_NoError) 1295 mDNSCoreInitComplete(m, mStatus_NoError); 1296 1297 return PosixErrorToStatus(err); 1298 } 1299 1300 // mDNS core calls this routine to clean up the platform-specific data. 1301 // In our case all we need to do is to tear down every network interface. 1302 mDNSexport void mDNSPlatformClose(mDNS *const m) 1303 { 1304 assert(m != NULL); 1305 ClearInterfaceList(m); 1306 if (m->p->unicastSocket4 != -1) 1307 { 1308 int ipv4_closed = close(m->p->unicastSocket4); 1309 assert(ipv4_closed == 0); 1310 } 1311 #if HAVE_IPV6 1312 if (m->p->unicastSocket6 != -1) 1313 { 1314 int ipv6_closed = close(m->p->unicastSocket6); 1315 assert(ipv6_closed == 0); 1316 } 1317 #endif 1318 } 1319 1320 mDNSexport mStatus mDNSPlatformPosixRefreshInterfaceList(mDNS *const m) 1321 { 1322 int err; 1323 ClearInterfaceList(m); 1324 err = SetupInterfaceList(m); 1325 return PosixErrorToStatus(err); 1326 } 1327 1328 #if COMPILER_LIKES_PRAGMA_MARK 1329 #pragma mark ***** Locking 1330 #endif 1331 1332 // On the Posix platform, locking is a no-op because we only ever enter 1333 // mDNS core on the main thread. 1334 1335 // mDNS core calls this routine when it wants to prevent 1336 // the platform from reentering mDNS core code. 1337 mDNSexport void mDNSPlatformLock (const mDNS *const m) 1338 { 1339 (void) m; // Unused 1340 } 1341 1342 // mDNS core calls this routine when it release the lock taken by 1343 // mDNSPlatformLock and allow the platform to reenter mDNS core code. 1344 mDNSexport void mDNSPlatformUnlock (const mDNS *const m) 1345 { 1346 (void) m; // Unused 1347 } 1348 1349 #if COMPILER_LIKES_PRAGMA_MARK 1350 #pragma mark ***** Strings 1351 #endif 1352 1353 // mDNS core calls this routine to copy C strings. 1354 // On the Posix platform this maps directly to the ANSI C strcpy. 1355 mDNSexport void mDNSPlatformStrCopy(void *dst, const void *src) 1356 { 1357 strcpy((char *)dst, (char *)src); 1358 } 1359 1360 // mDNS core calls this routine to get the length of a C string. 1361 // On the Posix platform this maps directly to the ANSI C strlen. 1362 mDNSexport mDNSu32 mDNSPlatformStrLen (const void *src) 1363 { 1364 return strlen((char*)src); 1365 } 1366 1367 // mDNS core calls this routine to copy memory. 1368 // On the Posix platform this maps directly to the ANSI C memcpy. 1369 mDNSexport void mDNSPlatformMemCopy(void *dst, const void *src, mDNSu32 len) 1370 { 1371 memcpy(dst, src, len); 1372 } 1373 1374 // mDNS core calls this routine to test whether blocks of memory are byte-for-byte 1375 // identical. On the Posix platform this is a simple wrapper around ANSI C memcmp. 1376 mDNSexport mDNSBool mDNSPlatformMemSame(const void *dst, const void *src, mDNSu32 len) 1377 { 1378 return memcmp(dst, src, len) == 0; 1379 } 1380 1381 // mDNS core calls this routine to clear blocks of memory. 1382 // On the Posix platform this is a simple wrapper around ANSI C memset. 1383 mDNSexport void mDNSPlatformMemZero(void *dst, mDNSu32 len) 1384 { 1385 memset(dst, 0, len); 1386 } 1387 1388 mDNSexport void * mDNSPlatformMemAllocate(mDNSu32 len) { return(malloc(len)); } 1389 mDNSexport void mDNSPlatformMemFree (void *mem) { free(mem); } 1390 1391 mDNSexport mDNSu32 mDNSPlatformRandomSeed(void) 1392 { 1393 struct timeval tv; 1394 gettimeofday(&tv, NULL); 1395 return(tv.tv_usec); 1396 } 1397 1398 mDNSexport mDNSs32 mDNSPlatformOneSecond = 1024; 1399 1400 mDNSexport mStatus mDNSPlatformTimeInit(void) 1401 { 1402 // No special setup is required on Posix -- we just use gettimeofday(); 1403 // This is not really safe, because gettimeofday can go backwards if the user manually changes the date or time 1404 // We should find a better way to do this 1405 return(mStatus_NoError); 1406 } 1407 1408 mDNSexport mDNSs32 mDNSPlatformRawTime() 1409 { 1410 struct timeval tv; 1411 gettimeofday(&tv, NULL); 1412 // tv.tv_sec is seconds since 1st January 1970 (GMT, with no adjustment for daylight savings time) 1413 // tv.tv_usec is microseconds since the start of this second (i.e. values 0 to 999999) 1414 // We use the lower 22 bits of tv.tv_sec for the top 22 bits of our result 1415 // and we multiply tv.tv_usec by 16 / 15625 to get a value in the range 0-1023 to go in the bottom 10 bits. 1416 // This gives us a proper modular (cyclic) counter that has a resolution of roughly 1ms (actually 1/1024 second) 1417 // and correctly cycles every 2^22 seconds (4194304 seconds = approx 48 days). 1418 return((tv.tv_sec << 10) | (tv.tv_usec * 16 / 15625)); 1419 } 1420 1421 mDNSexport mDNSs32 mDNSPlatformUTC(void) 1422 { 1423 return time(NULL); 1424 } 1425 1426 mDNSexport void mDNSPlatformSendWakeupPacket(mDNS *const m, mDNSInterfaceID InterfaceID, char *EthAddr, char *IPAddr, int iteration) 1427 { 1428 (void) m; 1429 (void) InterfaceID; 1430 (void) EthAddr; 1431 (void) IPAddr; 1432 (void) iteration; 1433 } 1434 1435 mDNSexport mDNSBool mDNSPlatformValidRecordForInterface(AuthRecord *rr, const NetworkInterfaceInfo *intf) 1436 { 1437 (void) rr; 1438 (void) intf; 1439 1440 return 1; 1441 } 1442 1443 mDNSlocal void mDNSPosixAddToFDSet(int *nfds, fd_set *readfds, int s) 1444 { 1445 if (*nfds < s + 1) *nfds = s + 1; 1446 FD_SET(s, readfds); 1447 } 1448 1449 mDNSexport void mDNSPosixGetFDSet(mDNS *m, int *nfds, fd_set *readfds, struct timeval *timeout) 1450 { 1451 mDNSs32 ticks; 1452 struct timeval interval; 1453 1454 // 1. Call mDNS_Execute() to let mDNSCore do what it needs to do 1455 mDNSs32 nextevent = mDNS_Execute(m); 1456 1457 // 2. Build our list of active file descriptors 1458 PosixNetworkInterface *info = (PosixNetworkInterface *)(m->HostInterfaces); 1459 if (m->p->unicastSocket4 != -1) mDNSPosixAddToFDSet(nfds, readfds, m->p->unicastSocket4); 1460 #if HAVE_IPV6 1461 if (m->p->unicastSocket6 != -1) mDNSPosixAddToFDSet(nfds, readfds, m->p->unicastSocket6); 1462 #endif 1463 while (info) 1464 { 1465 if (info->multicastSocket4 != -1) mDNSPosixAddToFDSet(nfds, readfds, info->multicastSocket4); 1466 #if HAVE_IPV6 1467 if (info->multicastSocket6 != -1) mDNSPosixAddToFDSet(nfds, readfds, info->multicastSocket6); 1468 #endif 1469 info = (PosixNetworkInterface *)(info->coreIntf.next); 1470 } 1471 1472 // 3. Calculate the time remaining to the next scheduled event (in struct timeval format) 1473 ticks = nextevent - mDNS_TimeNow(m); 1474 if (ticks < 1) ticks = 1; 1475 interval.tv_sec = ticks >> 10; // The high 22 bits are seconds 1476 interval.tv_usec = ((ticks & 0x3FF) * 15625) / 16; // The low 10 bits are 1024ths 1477 1478 // 4. If client's proposed timeout is more than what we want, then reduce it 1479 if (timeout->tv_sec > interval.tv_sec || 1480 (timeout->tv_sec == interval.tv_sec && timeout->tv_usec > interval.tv_usec)) 1481 *timeout = interval; 1482 } 1483 1484 mDNSexport void mDNSPosixProcessFDSet(mDNS *const m, fd_set *readfds) 1485 { 1486 PosixNetworkInterface *info; 1487 assert(m != NULL); 1488 assert(readfds != NULL); 1489 info = (PosixNetworkInterface *)(m->HostInterfaces); 1490 1491 if (m->p->unicastSocket4 != -1 && FD_ISSET(m->p->unicastSocket4, readfds)) 1492 { 1493 FD_CLR(m->p->unicastSocket4, readfds); 1494 SocketDataReady(m, NULL, m->p->unicastSocket4); 1495 } 1496 #if HAVE_IPV6 1497 if (m->p->unicastSocket6 != -1 && FD_ISSET(m->p->unicastSocket6, readfds)) 1498 { 1499 FD_CLR(m->p->unicastSocket6, readfds); 1500 SocketDataReady(m, NULL, m->p->unicastSocket6); 1501 } 1502 #endif 1503 1504 while (info) 1505 { 1506 if (info->multicastSocket4 != -1 && FD_ISSET(info->multicastSocket4, readfds)) 1507 { 1508 FD_CLR(info->multicastSocket4, readfds); 1509 SocketDataReady(m, info, info->multicastSocket4); 1510 } 1511 #if HAVE_IPV6 1512 if (info->multicastSocket6 != -1 && FD_ISSET(info->multicastSocket6, readfds)) 1513 { 1514 FD_CLR(info->multicastSocket6, readfds); 1515 SocketDataReady(m, info, info->multicastSocket6); 1516 } 1517 #endif 1518 info = (PosixNetworkInterface *)(info->coreIntf.next); 1519 } 1520 } 1521 1522 // update gMaxFD 1523 mDNSlocal void DetermineMaxEventFD(void) 1524 { 1525 PosixEventSource *iSource; 1526 1527 gMaxFD = 0; 1528 for (iSource=(PosixEventSource*)gEventSources.Head; iSource; iSource = iSource->Next) 1529 if (gMaxFD < iSource->fd) 1530 gMaxFD = iSource->fd; 1531 } 1532 1533 // Add a file descriptor to the set that mDNSPosixRunEventLoopOnce() listens to. 1534 mStatus mDNSPosixAddFDToEventLoop(int fd, mDNSPosixEventCallback callback, void *context) 1535 { 1536 PosixEventSource *newSource; 1537 1538 if (gEventSources.LinkOffset == 0) 1539 InitLinkedList(&gEventSources, offsetof(PosixEventSource, Next)); 1540 1541 if (fd >= (int) FD_SETSIZE || fd < 0) 1542 return mStatus_UnsupportedErr; 1543 if (callback == NULL) 1544 return mStatus_BadParamErr; 1545 1546 newSource = (PosixEventSource*) malloc(sizeof *newSource); 1547 if (NULL == newSource) 1548 return mStatus_NoMemoryErr; 1549 1550 newSource->Callback = callback; 1551 newSource->Context = context; 1552 newSource->fd = fd; 1553 1554 AddToTail(&gEventSources, newSource); 1555 FD_SET(fd, &gEventFDs); 1556 1557 DetermineMaxEventFD(); 1558 1559 return mStatus_NoError; 1560 } 1561 1562 // Remove a file descriptor from the set that mDNSPosixRunEventLoopOnce() listens to. 1563 mStatus mDNSPosixRemoveFDFromEventLoop(int fd) 1564 { 1565 PosixEventSource *iSource; 1566 1567 for (iSource=(PosixEventSource*)gEventSources.Head; iSource; iSource = iSource->Next) 1568 { 1569 if (fd == iSource->fd) 1570 { 1571 FD_CLR(fd, &gEventFDs); 1572 RemoveFromList(&gEventSources, iSource); 1573 free(iSource); 1574 DetermineMaxEventFD(); 1575 return mStatus_NoError; 1576 } 1577 } 1578 return mStatus_NoSuchNameErr; 1579 } 1580 1581 // Simply note the received signal in gEventSignals. 1582 mDNSlocal void NoteSignal(int signum) 1583 { 1584 sigaddset(&gEventSignals, signum); 1585 } 1586 1587 // Tell the event package to listen for signal and report it in mDNSPosixRunEventLoopOnce(). 1588 mStatus mDNSPosixListenForSignalInEventLoop(int signum) 1589 { 1590 struct sigaction action; 1591 mStatus err; 1592 1593 mDNSPlatformMemZero(&action, sizeof action); // more portable than member-wise assignment 1594 action.sa_handler = NoteSignal; 1595 err = sigaction(signum, &action, (struct sigaction*) NULL); 1596 1597 sigaddset(&gEventSignalSet, signum); 1598 1599 return err; 1600 } 1601 1602 // Tell the event package to stop listening for signal in mDNSPosixRunEventLoopOnce(). 1603 mStatus mDNSPosixIgnoreSignalInEventLoop(int signum) 1604 { 1605 struct sigaction action; 1606 mStatus err; 1607 1608 mDNSPlatformMemZero(&action, sizeof action); // more portable than member-wise assignment 1609 action.sa_handler = SIG_DFL; 1610 err = sigaction(signum, &action, (struct sigaction*) NULL); 1611 1612 sigdelset(&gEventSignalSet, signum); 1613 1614 return err; 1615 } 1616 1617 // Do a single pass through the attendent event sources and dispatch any found to their callbacks. 1618 // Return as soon as internal timeout expires, or a signal we're listening for is received. 1619 mStatus mDNSPosixRunEventLoopOnce(mDNS *m, const struct timeval *pTimeout, 1620 sigset_t *pSignalsReceived, mDNSBool *pDataDispatched) 1621 { 1622 fd_set listenFDs = gEventFDs; 1623 int fdMax = 0, numReady; 1624 struct timeval timeout = *pTimeout; 1625 1626 // Include the sockets that are listening to the wire in our select() set 1627 mDNSPosixGetFDSet(m, &fdMax, &listenFDs, &timeout); // timeout may get modified 1628 if (fdMax < gMaxFD) 1629 fdMax = gMaxFD; 1630 1631 numReady = select(fdMax + 1, &listenFDs, (fd_set*) NULL, (fd_set*) NULL, &timeout); 1632 1633 // If any data appeared, invoke its callback 1634 if (numReady > 0) 1635 { 1636 PosixEventSource *iSource; 1637 1638 (void) mDNSPosixProcessFDSet(m, &listenFDs); // call this first to process wire data for clients 1639 1640 for (iSource=(PosixEventSource*)gEventSources.Head; iSource; iSource = iSource->Next) 1641 { 1642 if (FD_ISSET(iSource->fd, &listenFDs)) 1643 { 1644 iSource->Callback(iSource->fd, 0, iSource->Context); 1645 break; // in case callback removed elements from gEventSources 1646 } 1647 } 1648 *pDataDispatched = mDNStrue; 1649 } 1650 else 1651 *pDataDispatched = mDNSfalse; 1652 1653 (void) sigprocmask(SIG_BLOCK, &gEventSignalSet, (sigset_t*) NULL); 1654 *pSignalsReceived = gEventSignals; 1655 sigemptyset(&gEventSignals); 1656 (void) sigprocmask(SIG_UNBLOCK, &gEventSignalSet, (sigset_t*) NULL); 1657 1658 return mStatus_NoError; 1659 } 1660
