1/* $NetBSD: getaddrinfo.c,v 1.82 2006/03/25 12:09:40 rpaulo Exp $ */ 2/* $KAME: getaddrinfo.c,v 1.29 2000/08/31 17:26:57 itojun Exp $ */ 3 4/* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33/* 34 * Issues to be discussed: 35 * - Thread safe-ness must be checked. 36 * - Return values. There are nonstandard return values defined and used 37 * in the source code. This is because RFC2553 is silent about which error 38 * code must be returned for which situation. 39 * - IPv4 classful (shortened) form. RFC2553 is silent about it. XNET 5.2 40 * says to use inet_aton() to convert IPv4 numeric to binary (alows 41 * classful form as a result). 42 * current code - disallow classful form for IPv4 (due to use of inet_pton). 43 * - freeaddrinfo(NULL). RFC2553 is silent about it. XNET 5.2 says it is 44 * invalid. 45 * current code - SEGV on freeaddrinfo(NULL) 46 * Note: 47 * - We use getipnodebyname() just for thread-safeness. There's no intent 48 * to let it do PF_UNSPEC (actually we never pass PF_UNSPEC to 49 * getipnodebyname(). 50 * - The code filters out AFs that are not supported by the kernel, 51 * when globbing NULL hostname (to loopback, or wildcard). Is it the right 52 * thing to do? What is the relationship with post-RFC2553 AI_ADDRCONFIG 53 * in ai_flags? 54 * - (post-2553) semantics of AI_ADDRCONFIG itself is too vague. 55 * (1) what should we do against numeric hostname (2) what should we do 56 * against NULL hostname (3) what is AI_ADDRCONFIG itself. AF not ready? 57 * non-loopback address configured? global address configured? 58 * - To avoid search order issue, we have a big amount of code duplicate 59 * from gethnamaddr.c and some other places. The issues that there's no 60 * lower layer function to lookup "IPv4 or IPv6" record. Calling 61 * gethostbyname2 from getaddrinfo will end up in wrong search order, as 62 * follows: 63 * - The code makes use of following calls when asked to resolver with 64 * ai_family = PF_UNSPEC: 65 * getipnodebyname(host, AF_INET6); 66 * getipnodebyname(host, AF_INET); 67 * This will result in the following queries if the node is configure to 68 * prefer /etc/hosts than DNS: 69 * lookup /etc/hosts for IPv6 address 70 * lookup DNS for IPv6 address 71 * lookup /etc/hosts for IPv4 address 72 * lookup DNS for IPv4 address 73 * which may not meet people's requirement. 74 * The right thing to happen is to have underlying layer which does 75 * PF_UNSPEC lookup (lookup both) and return chain of addrinfos. 76 * This would result in a bit of code duplicate with _dns_ghbyname() and 77 * friends. 78 */ 79 80#include <fcntl.h> 81#include <sys/cdefs.h> 82#include <sys/types.h> 83#include <sys/stat.h> 84#include <sys/param.h> 85#include <sys/socket.h> 86#include <sys/un.h> 87#include <net/if.h> 88#include <netinet/in.h> 89#include <arpa/inet.h> 90#include "arpa_nameser.h" 91#include <assert.h> 92#include <ctype.h> 93#include <errno.h> 94#include <netdb.h> 95#include "resolv_private.h" 96#include <stddef.h> 97#include <stdio.h> 98#include <stdlib.h> 99#include <string.h> 100#include <strings.h> 101#include <unistd.h> 102 103#include <syslog.h> 104#include <stdarg.h> 105#include "nsswitch.h" 106 107#ifdef ANDROID_CHANGES 108#include <sys/system_properties.h> 109#endif /* ANDROID_CHANGES */ 110 111typedef union sockaddr_union { 112 struct sockaddr generic; 113 struct sockaddr_in in; 114 struct sockaddr_in6 in6; 115} sockaddr_union; 116 117#define SUCCESS 0 118#define ANY 0 119#define YES 1 120#define NO 0 121 122static const char in_addrany[] = { 0, 0, 0, 0 }; 123static const char in_loopback[] = { 127, 0, 0, 1 }; 124#ifdef INET6 125static const char in6_addrany[] = { 126 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 127}; 128static const char in6_loopback[] = { 129 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 130}; 131#endif 132 133// This should be synchronized to ResponseCode.h 134static const int DnsProxyQueryResult = 222; 135 136static const struct afd { 137 int a_af; 138 int a_addrlen; 139 int a_socklen; 140 int a_off; 141 const char *a_addrany; 142 const char *a_loopback; 143 int a_scoped; 144} afdl [] = { 145#ifdef INET6 146 {PF_INET6, sizeof(struct in6_addr), 147 sizeof(struct sockaddr_in6), 148 offsetof(struct sockaddr_in6, sin6_addr), 149 in6_addrany, in6_loopback, 1}, 150#endif 151 {PF_INET, sizeof(struct in_addr), 152 sizeof(struct sockaddr_in), 153 offsetof(struct sockaddr_in, sin_addr), 154 in_addrany, in_loopback, 0}, 155 {0, 0, 0, 0, NULL, NULL, 0}, 156}; 157 158struct explore { 159 int e_af; 160 int e_socktype; 161 int e_protocol; 162 const char *e_protostr; 163 int e_wild; 164#define WILD_AF(ex) ((ex)->e_wild & 0x01) 165#define WILD_SOCKTYPE(ex) ((ex)->e_wild & 0x02) 166#define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04) 167}; 168 169static const struct explore explore[] = { 170#if 0 171 { PF_LOCAL, 0, ANY, ANY, NULL, 0x01 }, 172#endif 173#ifdef INET6 174 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, 175 { PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, 176 { PF_INET6, SOCK_RAW, ANY, NULL, 0x05 }, 177#endif 178 { PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, 179 { PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, 180 { PF_INET, SOCK_RAW, ANY, NULL, 0x05 }, 181 { PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, 182 { PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, 183 { PF_UNSPEC, SOCK_RAW, ANY, NULL, 0x05 }, 184 { -1, 0, 0, NULL, 0 }, 185}; 186 187#ifdef INET6 188#define PTON_MAX 16 189#else 190#define PTON_MAX 4 191#endif 192 193static const ns_src default_dns_files[] = { 194 { NSSRC_FILES, NS_SUCCESS }, 195 { NSSRC_DNS, NS_SUCCESS }, 196 { 0, 0 } 197}; 198 199#define MAXPACKET (64*1024) 200 201typedef union { 202 HEADER hdr; 203 u_char buf[MAXPACKET]; 204} querybuf; 205 206struct res_target { 207 struct res_target *next; 208 const char *name; /* domain name */ 209 int qclass, qtype; /* class and type of query */ 210 u_char *answer; /* buffer to put answer */ 211 int anslen; /* size of answer buffer */ 212 int n; /* result length */ 213}; 214 215static int str2number(const char *); 216static int explore_fqdn(const struct addrinfo *, const char *, 217 const char *, struct addrinfo **); 218static int explore_null(const struct addrinfo *, 219 const char *, struct addrinfo **); 220static int explore_numeric(const struct addrinfo *, const char *, 221 const char *, struct addrinfo **, const char *); 222static int explore_numeric_scope(const struct addrinfo *, const char *, 223 const char *, struct addrinfo **); 224static int get_canonname(const struct addrinfo *, 225 struct addrinfo *, const char *); 226static struct addrinfo *get_ai(const struct addrinfo *, 227 const struct afd *, const char *); 228static int get_portmatch(const struct addrinfo *, const char *); 229static int get_port(const struct addrinfo *, const char *, int); 230static const struct afd *find_afd(int); 231#ifdef INET6 232static int ip6_str2scopeid(char *, struct sockaddr_in6 *, u_int32_t *); 233#endif 234 235static struct addrinfo *getanswer(const querybuf *, int, const char *, int, 236 const struct addrinfo *); 237static int _dns_getaddrinfo(void *, void *, va_list); 238static void _sethtent(FILE **); 239static void _endhtent(FILE **); 240static struct addrinfo *_gethtent(FILE **, const char *, 241 const struct addrinfo *); 242static int _files_getaddrinfo(void *, void *, va_list); 243 244static int res_queryN(const char *, struct res_target *, res_state); 245static int res_searchN(const char *, struct res_target *, res_state); 246static int res_querydomainN(const char *, const char *, 247 struct res_target *, res_state); 248 249static const char * const ai_errlist[] = { 250 "Success", 251 "Address family for hostname not supported", /* EAI_ADDRFAMILY */ 252 "Temporary failure in name resolution", /* EAI_AGAIN */ 253 "Invalid value for ai_flags", /* EAI_BADFLAGS */ 254 "Non-recoverable failure in name resolution", /* EAI_FAIL */ 255 "ai_family not supported", /* EAI_FAMILY */ 256 "Memory allocation failure", /* EAI_MEMORY */ 257 "No address associated with hostname", /* EAI_NODATA */ 258 "hostname nor servname provided, or not known", /* EAI_NONAME */ 259 "servname not supported for ai_socktype", /* EAI_SERVICE */ 260 "ai_socktype not supported", /* EAI_SOCKTYPE */ 261 "System error returned in errno", /* EAI_SYSTEM */ 262 "Invalid value for hints", /* EAI_BADHINTS */ 263 "Resolved protocol is unknown", /* EAI_PROTOCOL */ 264 "Argument buffer overflow", /* EAI_OVERFLOW */ 265 "Unknown error", /* EAI_MAX */ 266}; 267 268/* XXX macros that make external reference is BAD. */ 269 270#define GET_AI(ai, afd, addr) \ 271do { \ 272 /* external reference: pai, error, and label free */ \ 273 (ai) = get_ai(pai, (afd), (addr)); \ 274 if ((ai) == NULL) { \ 275 error = EAI_MEMORY; \ 276 goto free; \ 277 } \ 278} while (/*CONSTCOND*/0) 279 280#define GET_PORT(ai, serv) \ 281do { \ 282 /* external reference: error and label free */ \ 283 error = get_port((ai), (serv), 0); \ 284 if (error != 0) \ 285 goto free; \ 286} while (/*CONSTCOND*/0) 287 288#define GET_CANONNAME(ai, str) \ 289do { \ 290 /* external reference: pai, error and label free */ \ 291 error = get_canonname(pai, (ai), (str)); \ 292 if (error != 0) \ 293 goto free; \ 294} while (/*CONSTCOND*/0) 295 296#define ERR(err) \ 297do { \ 298 /* external reference: error, and label bad */ \ 299 error = (err); \ 300 goto bad; \ 301 /*NOTREACHED*/ \ 302} while (/*CONSTCOND*/0) 303 304#define MATCH_FAMILY(x, y, w) \ 305 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || \ 306 (y) == PF_UNSPEC))) 307#define MATCH(x, y, w) \ 308 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY))) 309 310const char * 311gai_strerror(int ecode) 312{ 313 if (ecode < 0 || ecode > EAI_MAX) 314 ecode = EAI_MAX; 315 return ai_errlist[ecode]; 316} 317 318void 319freeaddrinfo(struct addrinfo *ai) 320{ 321 struct addrinfo *next; 322 323 assert(ai != NULL); 324 325 do { 326 next = ai->ai_next; 327 if (ai->ai_canonname) 328 free(ai->ai_canonname); 329 /* no need to free(ai->ai_addr) */ 330 free(ai); 331 ai = next; 332 } while (ai); 333} 334 335static int 336str2number(const char *p) 337{ 338 char *ep; 339 unsigned long v; 340 341 assert(p != NULL); 342 343 if (*p == '\0') 344 return -1; 345 ep = NULL; 346 errno = 0; 347 v = strtoul(p, &ep, 10); 348 if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX) 349 return v; 350 else 351 return -1; 352} 353 354/* 355 * Connect a UDP socket to a given unicast address. This will cause no network 356 * traffic, but will fail fast if the system has no or limited reachability to 357 * the destination (e.g., no IPv4 address, no IPv6 default route, ...). 358 */ 359static int 360_test_connect(int pf, struct sockaddr *addr, size_t addrlen) { 361 int s = socket(pf, SOCK_DGRAM, IPPROTO_UDP); 362 if (s < 0) 363 return 0; 364 int ret; 365 do { 366 ret = connect(s, addr, addrlen); 367 } while (ret < 0 && errno == EINTR); 368 int success = (ret == 0); 369 do { 370 ret = close(s); 371 } while (ret < 0 && errno == EINTR); 372 return success; 373} 374 375/* 376 * The following functions determine whether IPv4 or IPv6 connectivity is 377 * available in order to implement AI_ADDRCONFIG. 378 * 379 * Strictly speaking, AI_ADDRCONFIG should not look at whether connectivity is 380 * available, but whether addresses of the specified family are "configured 381 * on the local system". However, bionic doesn't currently support getifaddrs, 382 * so checking for connectivity is the next best thing. 383 */ 384static int 385_have_ipv6() { 386 static const struct sockaddr_in6 sin6_test = { 387 .sin6_family = AF_INET6, 388 .sin6_addr.s6_addr = { // 2000:: 389 0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} 390 }; 391 sockaddr_union addr = { .in6 = sin6_test }; 392 return _test_connect(PF_INET6, &addr.generic, sizeof(addr.in6)); 393} 394 395static int 396_have_ipv4() { 397 static const struct sockaddr_in sin_test = { 398 .sin_family = AF_INET, 399 .sin_addr.s_addr = __constant_htonl(0x08080808L) // 8.8.8.8 400 }; 401 sockaddr_union addr = { .in = sin_test }; 402 return _test_connect(PF_INET, &addr.generic, sizeof(addr.in)); 403} 404 405// Returns 0 on success, else returns non-zero on error (in which case 406// getaddrinfo should continue as normal) 407static int 408android_getaddrinfo_proxy( 409 const char *hostname, const char *servname, 410 const struct addrinfo *hints, struct addrinfo **res) 411{ 412 int sock; 413 const int one = 1; 414 struct sockaddr_un proxy_addr; 415 const char* cache_mode = getenv("ANDROID_DNS_MODE"); 416 FILE* proxy = NULL; 417 int success = 0; 418 419 // Clear this at start, as we use its non-NULLness later (in the 420 // error path) to decide if we have to free up any memory we 421 // allocated in the process (before failing). 422 *res = NULL; 423 424 if (cache_mode != NULL && strcmp(cache_mode, "local") == 0) { 425 // Don't use the proxy in local mode. This is used by the 426 // proxy itself. 427 return -1; 428 } 429 430 // Temporary cautious hack to disable the DNS proxy for processes 431 // requesting special treatment. Ideally the DNS proxy should 432 // accomodate these apps, though. 433 char propname[PROP_NAME_MAX]; 434 char propvalue[PROP_VALUE_MAX]; 435 snprintf(propname, sizeof(propname), "net.dns1.%d", getpid()); 436 if (__system_property_get(propname, propvalue) > 0) { 437 return -1; 438 } 439 440 // Bogus things we can't serialize. Don't use the proxy. 441 if ((hostname != NULL && 442 strcspn(hostname, " \n\r\t^'\"") != strlen(hostname)) || 443 (servname != NULL && 444 strcspn(servname, " \n\r\t^'\"") != strlen(servname))) { 445 return -1; 446 } 447 448 sock = socket(AF_UNIX, SOCK_STREAM, 0); 449 if (sock < 0) { 450 return -1; 451 } 452 453 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); 454 memset(&proxy_addr, 0, sizeof(proxy_addr)); 455 proxy_addr.sun_family = AF_UNIX; 456 strlcpy(proxy_addr.sun_path, "/dev/socket/dnsproxyd", 457 sizeof(proxy_addr.sun_path)); 458 if (TEMP_FAILURE_RETRY(connect(sock, 459 (const struct sockaddr*) &proxy_addr, 460 sizeof(proxy_addr))) != 0) { 461 close(sock); 462 return -1; 463 } 464 465 // Send the request. 466 proxy = fdopen(sock, "r+"); 467 if (fprintf(proxy, "getaddrinfo %s %s %d %d %d %d", 468 hostname == NULL ? "^" : hostname, 469 servname == NULL ? "^" : servname, 470 hints == NULL ? -1 : hints->ai_flags, 471 hints == NULL ? -1 : hints->ai_family, 472 hints == NULL ? -1 : hints->ai_socktype, 473 hints == NULL ? -1 : hints->ai_protocol) < 0) { 474 goto exit; 475 } 476 // literal NULL byte at end, required by FrameworkListener 477 if (fputc(0, proxy) == EOF || 478 fflush(proxy) != 0) { 479 goto exit; 480 } 481 482 char buf[4]; 483 // read result code for gethostbyaddr 484 if (fread(buf, 1, sizeof(buf), proxy) != sizeof(buf)) { 485 goto exit; 486 } 487 488 int result_code = (int)strtol(buf, NULL, 10); 489 // verify the code itself 490 if (result_code != DnsProxyQueryResult ) { 491 goto exit; 492 } 493 494 struct addrinfo* ai = NULL; 495 struct addrinfo** nextres = res; 496 while (1) { 497 uint32_t addrinfo_len; 498 if (fread(&addrinfo_len, sizeof(addrinfo_len), 499 1, proxy) != 1) { 500 break; 501 } 502 addrinfo_len = ntohl(addrinfo_len); 503 if (addrinfo_len == 0) { 504 success = 1; 505 break; 506 } 507 508 if (addrinfo_len < sizeof(struct addrinfo)) { 509 break; 510 } 511 struct addrinfo* ai = calloc(1, addrinfo_len + 512 sizeof(struct sockaddr_storage)); 513 if (ai == NULL) { 514 break; 515 } 516 517 if (fread(ai, addrinfo_len, 1, proxy) != 1) { 518 // Error; fall through. 519 break; 520 } 521 522 // Zero out the pointer fields we copied which aren't 523 // valid in this address space. 524 ai->ai_addr = NULL; 525 ai->ai_canonname = NULL; 526 ai->ai_next = NULL; 527 528 // struct sockaddr 529 uint32_t addr_len; 530 if (fread(&addr_len, sizeof(addr_len), 1, proxy) != 1) { 531 break; 532 } 533 addr_len = ntohl(addr_len); 534 if (addr_len != 0) { 535 if (addr_len > sizeof(struct sockaddr_storage)) { 536 // Bogus; too big. 537 break; 538 } 539 struct sockaddr* addr = (struct sockaddr*)(ai + 1); 540 if (fread(addr, addr_len, 1, proxy) != 1) { 541 break; 542 } 543 ai->ai_addr = addr; 544 } 545 546 // cannonname 547 uint32_t name_len; 548 if (fread(&name_len, sizeof(name_len), 1, proxy) != 1) { 549 break; 550 } 551 name_len = ntohl(name_len); 552 if (name_len != 0) { 553 ai->ai_canonname = (char*) malloc(name_len); 554 if (fread(ai->ai_canonname, name_len, 1, proxy) != 1) { 555 break; 556 } 557 if (ai->ai_canonname[name_len - 1] != '\0') { 558 // The proxy should be returning this 559 // NULL-terminated. 560 break; 561 } 562 } 563 564 *nextres = ai; 565 nextres = &ai->ai_next; 566 ai = NULL; 567 } 568 569 if (ai != NULL) { 570 // Clean up partially-built addrinfo that we never ended up 571 // attaching to the response. 572 freeaddrinfo(ai); 573 } 574exit: 575 if (proxy != NULL) { 576 fclose(proxy); 577 } 578 579 if (success) { 580 return 0; 581 } 582 583 // Proxy failed; fall through to local 584 // resolver case. But first clean up any 585 // memory we might've allocated. 586 if (*res) { 587 freeaddrinfo(*res); 588 *res = NULL; 589 } 590 return -1; 591} 592 593int 594getaddrinfo(const char *hostname, const char *servname, 595 const struct addrinfo *hints, struct addrinfo **res) 596{ 597 struct addrinfo sentinel; 598 struct addrinfo *cur; 599 int error = 0; 600 struct addrinfo ai; 601 struct addrinfo ai0; 602 struct addrinfo *pai; 603 const struct explore *ex; 604 605 /* hostname is allowed to be NULL */ 606 /* servname is allowed to be NULL */ 607 /* hints is allowed to be NULL */ 608 assert(res != NULL); 609 610 memset(&sentinel, 0, sizeof(sentinel)); 611 cur = &sentinel; 612 pai = &ai; 613 pai->ai_flags = 0; 614 pai->ai_family = PF_UNSPEC; 615 pai->ai_socktype = ANY; 616 pai->ai_protocol = ANY; 617 pai->ai_addrlen = 0; 618 pai->ai_canonname = NULL; 619 pai->ai_addr = NULL; 620 pai->ai_next = NULL; 621 622 if (hostname == NULL && servname == NULL) 623 return EAI_NONAME; 624 if (hints) { 625 /* error check for hints */ 626 if (hints->ai_addrlen || hints->ai_canonname || 627 hints->ai_addr || hints->ai_next) 628 ERR(EAI_BADHINTS); /* xxx */ 629 if (hints->ai_flags & ~AI_MASK) 630 ERR(EAI_BADFLAGS); 631 switch (hints->ai_family) { 632 case PF_UNSPEC: 633 case PF_INET: 634#ifdef INET6 635 case PF_INET6: 636#endif 637 break; 638 default: 639 ERR(EAI_FAMILY); 640 } 641 memcpy(pai, hints, sizeof(*pai)); 642 643 /* 644 * if both socktype/protocol are specified, check if they 645 * are meaningful combination. 646 */ 647 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) { 648 for (ex = explore; ex->e_af >= 0; ex++) { 649 if (pai->ai_family != ex->e_af) 650 continue; 651 if (ex->e_socktype == ANY) 652 continue; 653 if (ex->e_protocol == ANY) 654 continue; 655 if (pai->ai_socktype == ex->e_socktype 656 && pai->ai_protocol != ex->e_protocol) { 657 ERR(EAI_BADHINTS); 658 } 659 } 660 } 661 } 662 663 /* 664 * check for special cases. (1) numeric servname is disallowed if 665 * socktype/protocol are left unspecified. (2) servname is disallowed 666 * for raw and other inet{,6} sockets. 667 */ 668 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1) 669#ifdef PF_INET6 670 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1) 671#endif 672 ) { 673 ai0 = *pai; /* backup *pai */ 674 675 if (pai->ai_family == PF_UNSPEC) { 676#ifdef PF_INET6 677 pai->ai_family = PF_INET6; 678#else 679 pai->ai_family = PF_INET; 680#endif 681 } 682 error = get_portmatch(pai, servname); 683 if (error) 684 ERR(error); 685 686 *pai = ai0; 687 } 688 689 ai0 = *pai; 690 691 /* NULL hostname, or numeric hostname */ 692 for (ex = explore; ex->e_af >= 0; ex++) { 693 *pai = ai0; 694 695 /* PF_UNSPEC entries are prepared for DNS queries only */ 696 if (ex->e_af == PF_UNSPEC) 697 continue; 698 699 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex))) 700 continue; 701 if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex))) 702 continue; 703 if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex))) 704 continue; 705 706 if (pai->ai_family == PF_UNSPEC) 707 pai->ai_family = ex->e_af; 708 if (pai->ai_socktype == ANY && ex->e_socktype != ANY) 709 pai->ai_socktype = ex->e_socktype; 710 if (pai->ai_protocol == ANY && ex->e_protocol != ANY) 711 pai->ai_protocol = ex->e_protocol; 712 713 if (hostname == NULL) 714 error = explore_null(pai, servname, &cur->ai_next); 715 else 716 error = explore_numeric_scope(pai, hostname, servname, 717 &cur->ai_next); 718 719 if (error) 720 goto free; 721 722 while (cur->ai_next) 723 cur = cur->ai_next; 724 } 725 726 /* 727 * XXX 728 * If numeric representation of AF1 can be interpreted as FQDN 729 * representation of AF2, we need to think again about the code below. 730 */ 731 if (sentinel.ai_next) 732 goto good; 733 734 if (hostname == NULL) 735 ERR(EAI_NODATA); 736 if (pai->ai_flags & AI_NUMERICHOST) 737 ERR(EAI_NONAME); 738 739 /* 740 * BEGIN ANDROID CHANGES; proxying to the cache 741 */ 742 if (android_getaddrinfo_proxy(hostname, servname, hints, res) == 0) { 743 return 0; 744 } 745 746 /* 747 * hostname as alphabetical name. 748 * we would like to prefer AF_INET6 than AF_INET, so we'll make a 749 * outer loop by AFs. 750 */ 751 for (ex = explore; ex->e_af >= 0; ex++) { 752 *pai = ai0; 753 754 /* require exact match for family field */ 755 if (pai->ai_family != ex->e_af) 756 continue; 757 758 if (!MATCH(pai->ai_socktype, ex->e_socktype, 759 WILD_SOCKTYPE(ex))) { 760 continue; 761 } 762 if (!MATCH(pai->ai_protocol, ex->e_protocol, 763 WILD_PROTOCOL(ex))) { 764 continue; 765 } 766 767 if (pai->ai_socktype == ANY && ex->e_socktype != ANY) 768 pai->ai_socktype = ex->e_socktype; 769 if (pai->ai_protocol == ANY && ex->e_protocol != ANY) 770 pai->ai_protocol = ex->e_protocol; 771 772 error = explore_fqdn(pai, hostname, servname, 773 &cur->ai_next); 774 775 while (cur && cur->ai_next) 776 cur = cur->ai_next; 777 } 778 779 /* XXX */ 780 if (sentinel.ai_next) 781 error = 0; 782 783 if (error) 784 goto free; 785 if (error == 0) { 786 if (sentinel.ai_next) { 787 good: 788 *res = sentinel.ai_next; 789 return SUCCESS; 790 } else 791 error = EAI_FAIL; 792 } 793 free: 794 bad: 795 if (sentinel.ai_next) 796 freeaddrinfo(sentinel.ai_next); 797 *res = NULL; 798 return error; 799} 800 801/* 802 * FQDN hostname, DNS lookup 803 */ 804static int 805explore_fqdn(const struct addrinfo *pai, const char *hostname, 806 const char *servname, struct addrinfo **res) 807{ 808 struct addrinfo *result; 809 struct addrinfo *cur; 810 int error = 0; 811 static const ns_dtab dtab[] = { 812 NS_FILES_CB(_files_getaddrinfo, NULL) 813 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */ 814 NS_NIS_CB(_yp_getaddrinfo, NULL) 815 { 0, 0, 0 } 816 }; 817 818 assert(pai != NULL); 819 /* hostname may be NULL */ 820 /* servname may be NULL */ 821 assert(res != NULL); 822 823 result = NULL; 824 825 /* 826 * if the servname does not match socktype/protocol, ignore it. 827 */ 828 if (get_portmatch(pai, servname) != 0) 829 return 0; 830 831 switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo", 832 default_dns_files, hostname, pai)) { 833 case NS_TRYAGAIN: 834 error = EAI_AGAIN; 835 goto free; 836 case NS_UNAVAIL: 837 error = EAI_FAIL; 838 goto free; 839 case NS_NOTFOUND: 840 error = EAI_NODATA; 841 goto free; 842 case NS_SUCCESS: 843 error = 0; 844 for (cur = result; cur; cur = cur->ai_next) { 845 GET_PORT(cur, servname); 846 /* canonname should be filled already */ 847 } 848 break; 849 } 850 851 *res = result; 852 853 return 0; 854 855free: 856 if (result) 857 freeaddrinfo(result); 858 return error; 859} 860 861/* 862 * hostname == NULL. 863 * passive socket -> anyaddr (0.0.0.0 or ::) 864 * non-passive socket -> localhost (127.0.0.1 or ::1) 865 */ 866static int 867explore_null(const struct addrinfo *pai, const char *servname, 868 struct addrinfo **res) 869{ 870 int s; 871 const struct afd *afd; 872 struct addrinfo *cur; 873 struct addrinfo sentinel; 874 int error; 875 876 assert(pai != NULL); 877 /* servname may be NULL */ 878 assert(res != NULL); 879 880 *res = NULL; 881 sentinel.ai_next = NULL; 882 cur = &sentinel; 883 884 /* 885 * filter out AFs that are not supported by the kernel 886 * XXX errno? 887 */ 888 s = socket(pai->ai_family, SOCK_DGRAM, 0); 889 if (s < 0) { 890 if (errno != EMFILE) 891 return 0; 892 } else 893 close(s); 894 895 /* 896 * if the servname does not match socktype/protocol, ignore it. 897 */ 898 if (get_portmatch(pai, servname) != 0) 899 return 0; 900 901 afd = find_afd(pai->ai_family); 902 if (afd == NULL) 903 return 0; 904 905 if (pai->ai_flags & AI_PASSIVE) { 906 GET_AI(cur->ai_next, afd, afd->a_addrany); 907 /* xxx meaningless? 908 * GET_CANONNAME(cur->ai_next, "anyaddr"); 909 */ 910 GET_PORT(cur->ai_next, servname); 911 } else { 912 GET_AI(cur->ai_next, afd, afd->a_loopback); 913 /* xxx meaningless? 914 * GET_CANONNAME(cur->ai_next, "localhost"); 915 */ 916 GET_PORT(cur->ai_next, servname); 917 } 918 cur = cur->ai_next; 919 920 *res = sentinel.ai_next; 921 return 0; 922 923free: 924 if (sentinel.ai_next) 925 freeaddrinfo(sentinel.ai_next); 926 return error; 927} 928 929/* 930 * numeric hostname 931 */ 932static int 933explore_numeric(const struct addrinfo *pai, const char *hostname, 934 const char *servname, struct addrinfo **res, const char *canonname) 935{ 936 const struct afd *afd; 937 struct addrinfo *cur; 938 struct addrinfo sentinel; 939 int error; 940 char pton[PTON_MAX]; 941 942 assert(pai != NULL); 943 /* hostname may be NULL */ 944 /* servname may be NULL */ 945 assert(res != NULL); 946 947 *res = NULL; 948 sentinel.ai_next = NULL; 949 cur = &sentinel; 950 951 /* 952 * if the servname does not match socktype/protocol, ignore it. 953 */ 954 if (get_portmatch(pai, servname) != 0) 955 return 0; 956 957 afd = find_afd(pai->ai_family); 958 if (afd == NULL) 959 return 0; 960 961 switch (afd->a_af) { 962#if 0 /*X/Open spec*/ 963 case AF_INET: 964 if (inet_aton(hostname, (struct in_addr *)pton) == 1) { 965 if (pai->ai_family == afd->a_af || 966 pai->ai_family == PF_UNSPEC /*?*/) { 967 GET_AI(cur->ai_next, afd, pton); 968 GET_PORT(cur->ai_next, servname); 969 if ((pai->ai_flags & AI_CANONNAME)) { 970 /* 971 * Set the numeric address itself as 972 * the canonical name, based on a 973 * clarification in rfc2553bis-03. 974 */ 975 GET_CANONNAME(cur->ai_next, canonname); 976 } 977 while (cur && cur->ai_next) 978 cur = cur->ai_next; 979 } else 980 ERR(EAI_FAMILY); /*xxx*/ 981 } 982 break; 983#endif 984 default: 985 if (inet_pton(afd->a_af, hostname, pton) == 1) { 986 if (pai->ai_family == afd->a_af || 987 pai->ai_family == PF_UNSPEC /*?*/) { 988 GET_AI(cur->ai_next, afd, pton); 989 GET_PORT(cur->ai_next, servname); 990 if ((pai->ai_flags & AI_CANONNAME)) { 991 /* 992 * Set the numeric address itself as 993 * the canonical name, based on a 994 * clarification in rfc2553bis-03. 995 */ 996 GET_CANONNAME(cur->ai_next, canonname); 997 } 998 while (cur->ai_next) 999 cur = cur->ai_next; 1000 } else 1001 ERR(EAI_FAMILY); /*xxx*/ 1002 } 1003 break; 1004 } 1005 1006 *res = sentinel.ai_next; 1007 return 0; 1008 1009free: 1010bad: 1011 if (sentinel.ai_next) 1012 freeaddrinfo(sentinel.ai_next); 1013 return error; 1014} 1015 1016/* 1017 * numeric hostname with scope 1018 */ 1019static int 1020explore_numeric_scope(const struct addrinfo *pai, const char *hostname, 1021 const char *servname, struct addrinfo **res) 1022{ 1023#if !defined(SCOPE_DELIMITER) || !defined(INET6) 1024 return explore_numeric(pai, hostname, servname, res, hostname); 1025#else 1026 const struct afd *afd; 1027 struct addrinfo *cur; 1028 int error; 1029 char *cp, *hostname2 = NULL, *scope, *addr; 1030 struct sockaddr_in6 *sin6; 1031 1032 assert(pai != NULL); 1033 /* hostname may be NULL */ 1034 /* servname may be NULL */ 1035 assert(res != NULL); 1036 1037 /* 1038 * if the servname does not match socktype/protocol, ignore it. 1039 */ 1040 if (get_portmatch(pai, servname) != 0) 1041 return 0; 1042 1043 afd = find_afd(pai->ai_family); 1044 if (afd == NULL) 1045 return 0; 1046 1047 if (!afd->a_scoped) 1048 return explore_numeric(pai, hostname, servname, res, hostname); 1049 1050 cp = strchr(hostname, SCOPE_DELIMITER); 1051 if (cp == NULL) 1052 return explore_numeric(pai, hostname, servname, res, hostname); 1053 1054 /* 1055 * Handle special case of <scoped_address><delimiter><scope id> 1056 */ 1057 hostname2 = strdup(hostname); 1058 if (hostname2 == NULL) 1059 return EAI_MEMORY; 1060 /* terminate at the delimiter */ 1061 hostname2[cp - hostname] = '\0'; 1062 addr = hostname2; 1063 scope = cp + 1; 1064 1065 error = explore_numeric(pai, addr, servname, res, hostname); 1066 if (error == 0) { 1067 u_int32_t scopeid; 1068 1069 for (cur = *res; cur; cur = cur->ai_next) { 1070 if (cur->ai_family != AF_INET6) 1071 continue; 1072 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr; 1073 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) { 1074 free(hostname2); 1075 return(EAI_NODATA); /* XXX: is return OK? */ 1076 } 1077 sin6->sin6_scope_id = scopeid; 1078 } 1079 } 1080 1081 free(hostname2); 1082 1083 return error; 1084#endif 1085} 1086 1087static int 1088get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str) 1089{ 1090 1091 assert(pai != NULL); 1092 assert(ai != NULL); 1093 assert(str != NULL); 1094 1095 if ((pai->ai_flags & AI_CANONNAME) != 0) { 1096 ai->ai_canonname = strdup(str); 1097 if (ai->ai_canonname == NULL) 1098 return EAI_MEMORY; 1099 } 1100 return 0; 1101} 1102 1103static struct addrinfo * 1104get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr) 1105{ 1106 char *p; 1107 struct addrinfo *ai; 1108 1109 assert(pai != NULL); 1110 assert(afd != NULL); 1111 assert(addr != NULL); 1112 1113 ai = (struct addrinfo *)malloc(sizeof(struct addrinfo) 1114 + (afd->a_socklen)); 1115 if (ai == NULL) 1116 return NULL; 1117 1118 memcpy(ai, pai, sizeof(struct addrinfo)); 1119 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1); 1120 memset(ai->ai_addr, 0, (size_t)afd->a_socklen); 1121 1122#ifdef HAVE_SA_LEN 1123 ai->ai_addr->sa_len = afd->a_socklen; 1124#endif 1125 1126 ai->ai_addrlen = afd->a_socklen; 1127#if defined (__alpha__) || (defined(__i386__) && defined(_LP64)) || defined(__sparc64__) 1128 ai->__ai_pad0 = 0; 1129#endif 1130 ai->ai_addr->sa_family = ai->ai_family = afd->a_af; 1131 p = (char *)(void *)(ai->ai_addr); 1132 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen); 1133 return ai; 1134} 1135 1136static int 1137get_portmatch(const struct addrinfo *ai, const char *servname) 1138{ 1139 1140 assert(ai != NULL); 1141 /* servname may be NULL */ 1142 1143 return get_port(ai, servname, 1); 1144} 1145 1146static int 1147get_port(const struct addrinfo *ai, const char *servname, int matchonly) 1148{ 1149 const char *proto; 1150 struct servent *sp; 1151 int port; 1152 int allownumeric; 1153 1154 assert(ai != NULL); 1155 /* servname may be NULL */ 1156 1157 if (servname == NULL) 1158 return 0; 1159 switch (ai->ai_family) { 1160 case AF_INET: 1161#ifdef AF_INET6 1162 case AF_INET6: 1163#endif 1164 break; 1165 default: 1166 return 0; 1167 } 1168 1169 switch (ai->ai_socktype) { 1170 case SOCK_RAW: 1171 return EAI_SERVICE; 1172 case SOCK_DGRAM: 1173 case SOCK_STREAM: 1174 allownumeric = 1; 1175 break; 1176 case ANY: 1177#if 1 /* ANDROID-SPECIFIC CHANGE TO MATCH GLIBC */ 1178 allownumeric = 1; 1179#else 1180 allownumeric = 0; 1181#endif 1182 break; 1183 default: 1184 return EAI_SOCKTYPE; 1185 } 1186 1187 port = str2number(servname); 1188 if (port >= 0) { 1189 if (!allownumeric) 1190 return EAI_SERVICE; 1191 if (port < 0 || port > 65535) 1192 return EAI_SERVICE; 1193 port = htons(port); 1194 } else { 1195 if (ai->ai_flags & AI_NUMERICSERV) 1196 return EAI_NONAME; 1197 1198 switch (ai->ai_socktype) { 1199 case SOCK_DGRAM: 1200 proto = "udp"; 1201 break; 1202 case SOCK_STREAM: 1203 proto = "tcp"; 1204 break; 1205 default: 1206 proto = NULL; 1207 break; 1208 } 1209 1210 if ((sp = getservbyname(servname, proto)) == NULL) 1211 return EAI_SERVICE; 1212 port = sp->s_port; 1213 } 1214 1215 if (!matchonly) { 1216 switch (ai->ai_family) { 1217 case AF_INET: 1218 ((struct sockaddr_in *)(void *) 1219 ai->ai_addr)->sin_port = port; 1220 break; 1221#ifdef INET6 1222 case AF_INET6: 1223 ((struct sockaddr_in6 *)(void *) 1224 ai->ai_addr)->sin6_port = port; 1225 break; 1226#endif 1227 } 1228 } 1229 1230 return 0; 1231} 1232 1233static const struct afd * 1234find_afd(int af) 1235{ 1236 const struct afd *afd; 1237 1238 if (af == PF_UNSPEC) 1239 return NULL; 1240 for (afd = afdl; afd->a_af; afd++) { 1241 if (afd->a_af == af) 1242 return afd; 1243 } 1244 return NULL; 1245} 1246 1247#ifdef INET6 1248/* convert a string to a scope identifier. XXX: IPv6 specific */ 1249static int 1250ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid) 1251{ 1252 u_long lscopeid; 1253 struct in6_addr *a6; 1254 char *ep; 1255 1256 assert(scope != NULL); 1257 assert(sin6 != NULL); 1258 assert(scopeid != NULL); 1259 1260 a6 = &sin6->sin6_addr; 1261 1262 /* empty scopeid portion is invalid */ 1263 if (*scope == '\0') 1264 return -1; 1265 1266 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) { 1267 /* 1268 * We currently assume a one-to-one mapping between links 1269 * and interfaces, so we simply use interface indices for 1270 * like-local scopes. 1271 */ 1272 *scopeid = if_nametoindex(scope); 1273 if (*scopeid == 0) 1274 goto trynumeric; 1275 return 0; 1276 } 1277 1278 /* still unclear about literal, allow numeric only - placeholder */ 1279 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6)) 1280 goto trynumeric; 1281 if (IN6_IS_ADDR_MC_ORGLOCAL(a6)) 1282 goto trynumeric; 1283 else 1284 goto trynumeric; /* global */ 1285 1286 /* try to convert to a numeric id as a last resort */ 1287 trynumeric: 1288 errno = 0; 1289 lscopeid = strtoul(scope, &ep, 10); 1290 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL); 1291 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid) 1292 return 0; 1293 else 1294 return -1; 1295} 1296#endif 1297 1298/* code duplicate with gethnamaddr.c */ 1299 1300static const char AskedForGot[] = 1301 "gethostby*.getanswer: asked for \"%s\", got \"%s\""; 1302 1303static struct addrinfo * 1304getanswer(const querybuf *answer, int anslen, const char *qname, int qtype, 1305 const struct addrinfo *pai) 1306{ 1307 struct addrinfo sentinel, *cur; 1308 struct addrinfo ai; 1309 const struct afd *afd; 1310 char *canonname; 1311 const HEADER *hp; 1312 const u_char *cp; 1313 int n; 1314 const u_char *eom; 1315 char *bp, *ep; 1316 int type, class, ancount, qdcount; 1317 int haveanswer, had_error; 1318 char tbuf[MAXDNAME]; 1319 int (*name_ok) (const char *); 1320 char hostbuf[8*1024]; 1321 1322 assert(answer != NULL); 1323 assert(qname != NULL); 1324 assert(pai != NULL); 1325 1326 memset(&sentinel, 0, sizeof(sentinel)); 1327 cur = &sentinel; 1328 1329 canonname = NULL; 1330 eom = answer->buf + anslen; 1331 switch (qtype) { 1332 case T_A: 1333 case T_AAAA: 1334 case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/ 1335 name_ok = res_hnok; 1336 break; 1337 default: 1338 return NULL; /* XXX should be abort(); */ 1339 } 1340 /* 1341 * find first satisfactory answer 1342 */ 1343 hp = &answer->hdr; 1344 ancount = ntohs(hp->ancount); 1345 qdcount = ntohs(hp->qdcount); 1346 bp = hostbuf; 1347 ep = hostbuf + sizeof hostbuf; 1348 cp = answer->buf + HFIXEDSZ; 1349 if (qdcount != 1) { 1350 h_errno = NO_RECOVERY; 1351 return (NULL); 1352 } 1353 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 1354 if ((n < 0) || !(*name_ok)(bp)) { 1355 h_errno = NO_RECOVERY; 1356 return (NULL); 1357 } 1358 cp += n + QFIXEDSZ; 1359 if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) { 1360 /* res_send() has already verified that the query name is the 1361 * same as the one we sent; this just gets the expanded name 1362 * (i.e., with the succeeding search-domain tacked on). 1363 */ 1364 n = strlen(bp) + 1; /* for the \0 */ 1365 if (n >= MAXHOSTNAMELEN) { 1366 h_errno = NO_RECOVERY; 1367 return (NULL); 1368 } 1369 canonname = bp; 1370 bp += n; 1371 /* The qname can be abbreviated, but h_name is now absolute. */ 1372 qname = canonname; 1373 } 1374 haveanswer = 0; 1375 had_error = 0; 1376 while (ancount-- > 0 && cp < eom && !had_error) { 1377 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 1378 if ((n < 0) || !(*name_ok)(bp)) { 1379 had_error++; 1380 continue; 1381 } 1382 cp += n; /* name */ 1383 type = _getshort(cp); 1384 cp += INT16SZ; /* type */ 1385 class = _getshort(cp); 1386 cp += INT16SZ + INT32SZ; /* class, TTL */ 1387 n = _getshort(cp); 1388 cp += INT16SZ; /* len */ 1389 if (class != C_IN) { 1390 /* XXX - debug? syslog? */ 1391 cp += n; 1392 continue; /* XXX - had_error++ ? */ 1393 } 1394 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) && 1395 type == T_CNAME) { 1396 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); 1397 if ((n < 0) || !(*name_ok)(tbuf)) { 1398 had_error++; 1399 continue; 1400 } 1401 cp += n; 1402 /* Get canonical name. */ 1403 n = strlen(tbuf) + 1; /* for the \0 */ 1404 if (n > ep - bp || n >= MAXHOSTNAMELEN) { 1405 had_error++; 1406 continue; 1407 } 1408 strlcpy(bp, tbuf, (size_t)(ep - bp)); 1409 canonname = bp; 1410 bp += n; 1411 continue; 1412 } 1413 if (qtype == T_ANY) { 1414 if (!(type == T_A || type == T_AAAA)) { 1415 cp += n; 1416 continue; 1417 } 1418 } else if (type != qtype) { 1419 if (type != T_KEY && type != T_SIG) 1420 syslog(LOG_NOTICE|LOG_AUTH, 1421 "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"", 1422 qname, p_class(C_IN), p_type(qtype), 1423 p_type(type)); 1424 cp += n; 1425 continue; /* XXX - had_error++ ? */ 1426 } 1427 switch (type) { 1428 case T_A: 1429 case T_AAAA: 1430 if (strcasecmp(canonname, bp) != 0) { 1431 syslog(LOG_NOTICE|LOG_AUTH, 1432 AskedForGot, canonname, bp); 1433 cp += n; 1434 continue; /* XXX - had_error++ ? */ 1435 } 1436 if (type == T_A && n != INADDRSZ) { 1437 cp += n; 1438 continue; 1439 } 1440 if (type == T_AAAA && n != IN6ADDRSZ) { 1441 cp += n; 1442 continue; 1443 } 1444 if (type == T_AAAA) { 1445 struct in6_addr in6; 1446 memcpy(&in6, cp, IN6ADDRSZ); 1447 if (IN6_IS_ADDR_V4MAPPED(&in6)) { 1448 cp += n; 1449 continue; 1450 } 1451 } 1452 if (!haveanswer) { 1453 int nn; 1454 1455 canonname = bp; 1456 nn = strlen(bp) + 1; /* for the \0 */ 1457 bp += nn; 1458 } 1459 1460 /* don't overwrite pai */ 1461 ai = *pai; 1462 ai.ai_family = (type == T_A) ? AF_INET : AF_INET6; 1463 afd = find_afd(ai.ai_family); 1464 if (afd == NULL) { 1465 cp += n; 1466 continue; 1467 } 1468 cur->ai_next = get_ai(&ai, afd, (const char *)cp); 1469 if (cur->ai_next == NULL) 1470 had_error++; 1471 while (cur && cur->ai_next) 1472 cur = cur->ai_next; 1473 cp += n; 1474 break; 1475 default: 1476 abort(); 1477 } 1478 if (!had_error) 1479 haveanswer++; 1480 } 1481 if (haveanswer) { 1482 if (!canonname) 1483 (void)get_canonname(pai, sentinel.ai_next, qname); 1484 else 1485 (void)get_canonname(pai, sentinel.ai_next, canonname); 1486 h_errno = NETDB_SUCCESS; 1487 return sentinel.ai_next; 1488 } 1489 1490 h_errno = NO_RECOVERY; 1491 return NULL; 1492} 1493 1494struct addrinfo_sort_elem { 1495 struct addrinfo *ai; 1496 int has_src_addr; 1497 sockaddr_union src_addr; 1498 int original_order; 1499}; 1500 1501/*ARGSUSED*/ 1502static int 1503_get_scope(const struct sockaddr *addr) 1504{ 1505 if (addr->sa_family == AF_INET6) { 1506 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr; 1507 if (IN6_IS_ADDR_MULTICAST(&addr6->sin6_addr)) { 1508 return IPV6_ADDR_MC_SCOPE(&addr6->sin6_addr); 1509 } else if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr) || 1510 IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr)) { 1511 /* 1512 * RFC 4291 section 2.5.3 says loopback is to be treated as having 1513 * link-local scope. 1514 */ 1515 return IPV6_ADDR_SCOPE_LINKLOCAL; 1516 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) { 1517 return IPV6_ADDR_SCOPE_SITELOCAL; 1518 } else { 1519 return IPV6_ADDR_SCOPE_GLOBAL; 1520 } 1521 } else if (addr->sa_family == AF_INET) { 1522 const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr; 1523 unsigned long int na = ntohl(addr4->sin_addr.s_addr); 1524 1525 if (IN_LOOPBACK(na) || /* 127.0.0.0/8 */ 1526 (na & 0xffff0000) == 0xa9fe0000) { /* 169.254.0.0/16 */ 1527 return IPV6_ADDR_SCOPE_LINKLOCAL; 1528 } else { 1529 /* 1530 * According to draft-ietf-6man-rfc3484-revise-01 section 2.3, 1531 * it is best not to treat the private IPv4 ranges 1532 * (10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16) as being 1533 * in a special scope, so we don't. 1534 */ 1535 return IPV6_ADDR_SCOPE_GLOBAL; 1536 } 1537 } else { 1538 /* 1539 * This should never happen. 1540 * Return a scope with low priority as a last resort. 1541 */ 1542 return IPV6_ADDR_SCOPE_NODELOCAL; 1543 } 1544} 1545 1546/* These macros are modelled after the ones in <netinet/in6.h>. */ 1547 1548/* RFC 4380, section 2.6 */ 1549#define IN6_IS_ADDR_TEREDO(a) \ 1550 ((*(const uint32_t *)(const void *)(&(a)->s6_addr[0]) == ntohl(0x20010000))) 1551 1552/* RFC 3056, section 2. */ 1553#define IN6_IS_ADDR_6TO4(a) \ 1554 (((a)->s6_addr[0] == 0x20) && ((a)->s6_addr[1] == 0x02)) 1555 1556/* 6bone testing address area (3ffe::/16), deprecated in RFC 3701. */ 1557#define IN6_IS_ADDR_6BONE(a) \ 1558 (((a)->s6_addr[0] == 0x3f) && ((a)->s6_addr[1] == 0xfe)) 1559 1560/* 1561 * Get the label for a given IPv4/IPv6 address. 1562 * RFC 3484, section 2.1, plus changes from draft-ietf-6man-rfc3484-revise-01. 1563 */ 1564 1565/*ARGSUSED*/ 1566static int 1567_get_label(const struct sockaddr *addr) 1568{ 1569 if (addr->sa_family == AF_INET) { 1570 return 3; 1571 } else if (addr->sa_family == AF_INET6) { 1572 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr; 1573 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) { 1574 return 0; 1575 } else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) { 1576 return 1; 1577 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) { 1578 return 3; 1579 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) { 1580 return 4; 1581 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) { 1582 return 5; 1583 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr)) { 1584 return 10; 1585 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) { 1586 return 11; 1587 } else if (IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) { 1588 return 12; 1589 } else { 1590 return 2; 1591 } 1592 } else { 1593 /* 1594 * This should never happen. 1595 * Return a semi-random label as a last resort. 1596 */ 1597 return 1; 1598 } 1599} 1600 1601/* 1602 * Get the precedence for a given IPv4/IPv6 address. 1603 * RFC 3484, section 2.1, plus changes from draft-ietf-6man-rfc3484-revise-01. 1604 */ 1605 1606/*ARGSUSED*/ 1607static int 1608_get_precedence(const struct sockaddr *addr) 1609{ 1610 if (addr->sa_family == AF_INET) { 1611 return 30; 1612 } else if (addr->sa_family == AF_INET6) { 1613 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr; 1614 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) { 1615 return 60; 1616 } else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) { 1617 return 50; 1618 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) { 1619 return 30; 1620 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) { 1621 return 20; 1622 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) { 1623 return 10; 1624 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr) || 1625 IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr) || 1626 IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) { 1627 return 1; 1628 } else { 1629 return 40; 1630 } 1631 } else { 1632 return 1; 1633 } 1634} 1635 1636/* 1637 * Find number of matching initial bits between the two addresses a1 and a2. 1638 */ 1639 1640/*ARGSUSED*/ 1641static int 1642_common_prefix_len(const struct in6_addr *a1, const struct in6_addr *a2) 1643{ 1644 const char *p1 = (const char *)a1; 1645 const char *p2 = (const char *)a2; 1646 unsigned i; 1647 1648 for (i = 0; i < sizeof(*a1); ++i) { 1649 int x, j; 1650 1651 if (p1[i] == p2[i]) { 1652 continue; 1653 } 1654 x = p1[i] ^ p2[i]; 1655 for (j = 0; j < CHAR_BIT; ++j) { 1656 if (x & (1 << (CHAR_BIT - 1))) { 1657 return i * CHAR_BIT + j; 1658 } 1659 x <<= 1; 1660 } 1661 } 1662 return sizeof(*a1) * CHAR_BIT; 1663} 1664 1665/* 1666 * Compare two source/destination address pairs. 1667 * RFC 3484, section 6. 1668 */ 1669 1670/*ARGSUSED*/ 1671static int 1672_rfc3484_compare(const void *ptr1, const void* ptr2) 1673{ 1674 const struct addrinfo_sort_elem *a1 = (const struct addrinfo_sort_elem *)ptr1; 1675 const struct addrinfo_sort_elem *a2 = (const struct addrinfo_sort_elem *)ptr2; 1676 int scope_src1, scope_dst1, scope_match1; 1677 int scope_src2, scope_dst2, scope_match2; 1678 int label_src1, label_dst1, label_match1; 1679 int label_src2, label_dst2, label_match2; 1680 int precedence1, precedence2; 1681 int prefixlen1, prefixlen2; 1682 1683 /* Rule 1: Avoid unusable destinations. */ 1684 if (a1->has_src_addr != a2->has_src_addr) { 1685 return a2->has_src_addr - a1->has_src_addr; 1686 } 1687 1688 /* Rule 2: Prefer matching scope. */ 1689 scope_src1 = _get_scope(&a1->src_addr.generic); 1690 scope_dst1 = _get_scope(a1->ai->ai_addr); 1691 scope_match1 = (scope_src1 == scope_dst1); 1692 1693 scope_src2 = _get_scope(&a2->src_addr.generic); 1694 scope_dst2 = _get_scope(a2->ai->ai_addr); 1695 scope_match2 = (scope_src2 == scope_dst2); 1696 1697 if (scope_match1 != scope_match2) { 1698 return scope_match2 - scope_match1; 1699 } 1700 1701 /* 1702 * Rule 3: Avoid deprecated addresses. 1703 * TODO(sesse): We don't currently have a good way of finding this. 1704 */ 1705 1706 /* 1707 * Rule 4: Prefer home addresses. 1708 * TODO(sesse): We don't currently have a good way of finding this. 1709 */ 1710 1711 /* Rule 5: Prefer matching label. */ 1712 label_src1 = _get_label(&a1->src_addr.generic); 1713 label_dst1 = _get_label(a1->ai->ai_addr); 1714 label_match1 = (label_src1 == label_dst1); 1715 1716 label_src2 = _get_label(&a2->src_addr.generic); 1717 label_dst2 = _get_label(a2->ai->ai_addr); 1718 label_match2 = (label_src2 == label_dst2); 1719 1720 if (label_match1 != label_match2) { 1721 return label_match2 - label_match1; 1722 } 1723 1724 /* Rule 6: Prefer higher precedence. */ 1725 precedence1 = _get_precedence(a1->ai->ai_addr); 1726 precedence2 = _get_precedence(a2->ai->ai_addr); 1727 if (precedence1 != precedence2) { 1728 return precedence2 - precedence1; 1729 } 1730 1731 /* 1732 * Rule 7: Prefer native transport. 1733 * TODO(sesse): We don't currently have a good way of finding this. 1734 */ 1735 1736 /* Rule 8: Prefer smaller scope. */ 1737 if (scope_dst1 != scope_dst2) { 1738 return scope_dst1 - scope_dst2; 1739 } 1740 1741 /* 1742 * Rule 9: Use longest matching prefix. 1743 * We implement this for IPv6 only, as the rules in RFC 3484 don't seem 1744 * to work very well directly applied to IPv4. (glibc uses information from 1745 * the routing table for a custom IPv4 implementation here.) 1746 */ 1747 if (a1->has_src_addr && a1->ai->ai_addr->sa_family == AF_INET6 && 1748 a2->has_src_addr && a2->ai->ai_addr->sa_family == AF_INET6) { 1749 const struct sockaddr_in6 *a1_src = &a1->src_addr.in6; 1750 const struct sockaddr_in6 *a1_dst = (const struct sockaddr_in6 *)a1->ai->ai_addr; 1751 const struct sockaddr_in6 *a2_src = &a2->src_addr.in6; 1752 const struct sockaddr_in6 *a2_dst = (const struct sockaddr_in6 *)a2->ai->ai_addr; 1753 prefixlen1 = _common_prefix_len(&a1_src->sin6_addr, &a1_dst->sin6_addr); 1754 prefixlen2 = _common_prefix_len(&a2_src->sin6_addr, &a2_dst->sin6_addr); 1755 if (prefixlen1 != prefixlen2) { 1756 return prefixlen2 - prefixlen1; 1757 } 1758 } 1759 1760 /* 1761 * Rule 10: Leave the order unchanged. 1762 * We need this since qsort() is not necessarily stable. 1763 */ 1764 return a1->original_order - a2->original_order; 1765} 1766 1767/* 1768 * Find the source address that will be used if trying to connect to the given 1769 * address. src_addr must be large enough to hold a struct sockaddr_in6. 1770 * 1771 * Returns 1 if a source address was found, 0 if the address is unreachable, 1772 * and -1 if a fatal error occurred. If 0 or 1, the contents of src_addr are 1773 * undefined. 1774 */ 1775 1776/*ARGSUSED*/ 1777static int 1778_find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr) 1779{ 1780 int sock; 1781 int ret; 1782 socklen_t len; 1783 1784 switch (addr->sa_family) { 1785 case AF_INET: 1786 len = sizeof(struct sockaddr_in); 1787 break; 1788 case AF_INET6: 1789 len = sizeof(struct sockaddr_in6); 1790 break; 1791 default: 1792 /* No known usable source address for non-INET families. */ 1793 return 0; 1794 } 1795 1796 sock = socket(addr->sa_family, SOCK_DGRAM, IPPROTO_UDP); 1797 if (sock == -1) { 1798 if (errno == EAFNOSUPPORT) { 1799 return 0; 1800 } else { 1801 return -1; 1802 } 1803 } 1804 1805 do { 1806 ret = connect(sock, addr, len); 1807 } while (ret == -1 && errno == EINTR); 1808 1809 if (ret == -1) { 1810 close(sock); 1811 return 0; 1812 } 1813 1814 if (getsockname(sock, src_addr, &len) == -1) { 1815 close(sock); 1816 return -1; 1817 } 1818 close(sock); 1819 return 1; 1820} 1821 1822/* 1823 * Sort the linked list starting at sentinel->ai_next in RFC3484 order. 1824 * Will leave the list unchanged if an error occurs. 1825 */ 1826 1827/*ARGSUSED*/ 1828static void 1829_rfc3484_sort(struct addrinfo *list_sentinel) 1830{ 1831 struct addrinfo *cur; 1832 int nelem = 0, i; 1833 struct addrinfo_sort_elem *elems; 1834 1835 cur = list_sentinel->ai_next; 1836 while (cur) { 1837 ++nelem; 1838 cur = cur->ai_next; 1839 } 1840 1841 elems = (struct addrinfo_sort_elem *)malloc(nelem * sizeof(struct addrinfo_sort_elem)); 1842 if (elems == NULL) { 1843 goto error; 1844 } 1845 1846 /* 1847 * Convert the linked list to an array that also contains the candidate 1848 * source address for each destination address. 1849 */ 1850 for (i = 0, cur = list_sentinel->ai_next; i < nelem; ++i, cur = cur->ai_next) { 1851 int has_src_addr; 1852 assert(cur != NULL); 1853 elems[i].ai = cur; 1854 elems[i].original_order = i; 1855 1856 has_src_addr = _find_src_addr(cur->ai_addr, &elems[i].src_addr.generic); 1857 if (has_src_addr == -1) { 1858 goto error; 1859 } 1860 elems[i].has_src_addr = has_src_addr; 1861 } 1862 1863 /* Sort the addresses, and rearrange the linked list so it matches the sorted order. */ 1864 qsort((void *)elems, nelem, sizeof(struct addrinfo_sort_elem), _rfc3484_compare); 1865 1866 list_sentinel->ai_next = elems[0].ai; 1867 for (i = 0; i < nelem - 1; ++i) { 1868 elems[i].ai->ai_next = elems[i + 1].ai; 1869 } 1870 elems[nelem - 1].ai->ai_next = NULL; 1871 1872error: 1873 free(elems); 1874} 1875 1876static int _using_alt_dns() 1877{ 1878 char propname[PROP_NAME_MAX]; 1879 char propvalue[PROP_VALUE_MAX]; 1880 1881 propvalue[0] = 0; 1882 snprintf(propname, sizeof(propname), "net.dns1.%d", getpid()); 1883 if (__system_property_get(propname, propvalue) > 0 ) { 1884 return 1; 1885 } 1886 return 0; 1887} 1888 1889/*ARGSUSED*/ 1890static int 1891_dns_getaddrinfo(void *rv, void *cb_data, va_list ap) 1892{ 1893 struct addrinfo *ai; 1894 querybuf *buf, *buf2; 1895 const char *name; 1896 const struct addrinfo *pai; 1897 struct addrinfo sentinel, *cur; 1898 struct res_target q, q2; 1899 res_state res; 1900 1901 name = va_arg(ap, char *); 1902 pai = va_arg(ap, const struct addrinfo *); 1903 //fprintf(stderr, "_dns_getaddrinfo() name = '%s'\n", name); 1904 1905 memset(&q, 0, sizeof(q)); 1906 memset(&q2, 0, sizeof(q2)); 1907 memset(&sentinel, 0, sizeof(sentinel)); 1908 cur = &sentinel; 1909 1910 buf = malloc(sizeof(*buf)); 1911 if (buf == NULL) { 1912 h_errno = NETDB_INTERNAL; 1913 return NS_NOTFOUND; 1914 } 1915 buf2 = malloc(sizeof(*buf2)); 1916 if (buf2 == NULL) { 1917 free(buf); 1918 h_errno = NETDB_INTERNAL; 1919 return NS_NOTFOUND; 1920 } 1921 1922 switch (pai->ai_family) { 1923 case AF_UNSPEC: 1924 /* prefer IPv6 */ 1925 q.name = name; 1926 q.qclass = C_IN; 1927 q.answer = buf->buf; 1928 q.anslen = sizeof(buf->buf); 1929 int query_ipv6 = 1, query_ipv4 = 1; 1930 if (pai->ai_flags & AI_ADDRCONFIG) { 1931 // Only implement AI_ADDRCONFIG if the application is not 1932 // using its own DNS servers, since our implementation 1933 // only works on the default connection. 1934 if (!_using_alt_dns()) { 1935 query_ipv6 = _have_ipv6(); 1936 query_ipv4 = _have_ipv4(); 1937 } 1938 } 1939 if (query_ipv6) { 1940 q.qtype = T_AAAA; 1941 if (query_ipv4) { 1942 q.next = &q2; 1943 q2.name = name; 1944 q2.qclass = C_IN; 1945 q2.qtype = T_A; 1946 q2.answer = buf2->buf; 1947 q2.anslen = sizeof(buf2->buf); 1948 } 1949 } else if (query_ipv4) { 1950 q.qtype = T_A; 1951 } else { 1952 free(buf); 1953 free(buf2); 1954 return NS_NOTFOUND; 1955 } 1956 break; 1957 case AF_INET: 1958 q.name = name; 1959 q.qclass = C_IN; 1960 q.qtype = T_A; 1961 q.answer = buf->buf; 1962 q.anslen = sizeof(buf->buf); 1963 break; 1964 case AF_INET6: 1965 q.name = name; 1966 q.qclass = C_IN; 1967 q.qtype = T_AAAA; 1968 q.answer = buf->buf; 1969 q.anslen = sizeof(buf->buf); 1970 break; 1971 default: 1972 free(buf); 1973 free(buf2); 1974 return NS_UNAVAIL; 1975 } 1976 1977 res = __res_get_state(); 1978 if (res == NULL) { 1979 free(buf); 1980 free(buf2); 1981 return NS_NOTFOUND; 1982 } 1983 1984 if (res_searchN(name, &q, res) < 0) { 1985 __res_put_state(res); 1986 free(buf); 1987 free(buf2); 1988 return NS_NOTFOUND; 1989 } 1990 ai = getanswer(buf, q.n, q.name, q.qtype, pai); 1991 if (ai) { 1992 cur->ai_next = ai; 1993 while (cur && cur->ai_next) 1994 cur = cur->ai_next; 1995 } 1996 if (q.next) { 1997 ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai); 1998 if (ai) 1999 cur->ai_next = ai; 2000 } 2001 free(buf); 2002 free(buf2); 2003 if (sentinel.ai_next == NULL) { 2004 __res_put_state(res); 2005 switch (h_errno) { 2006 case HOST_NOT_FOUND: 2007 return NS_NOTFOUND; 2008 case TRY_AGAIN: 2009 return NS_TRYAGAIN; 2010 default: 2011 return NS_UNAVAIL; 2012 } 2013 } 2014 2015 _rfc3484_sort(&sentinel); 2016 2017 __res_put_state(res); 2018 2019 *((struct addrinfo **)rv) = sentinel.ai_next; 2020 return NS_SUCCESS; 2021} 2022 2023static void 2024_sethtent(FILE **hostf) 2025{ 2026 2027 if (!*hostf) 2028 *hostf = fopen(_PATH_HOSTS, "r" ); 2029 else 2030 rewind(*hostf); 2031} 2032 2033static void 2034_endhtent(FILE **hostf) 2035{ 2036 2037 if (*hostf) { 2038 (void) fclose(*hostf); 2039 *hostf = NULL; 2040 } 2041} 2042 2043static struct addrinfo * 2044_gethtent(FILE **hostf, const char *name, const struct addrinfo *pai) 2045{ 2046 char *p; 2047 char *cp, *tname, *cname; 2048 struct addrinfo hints, *res0, *res; 2049 int error; 2050 const char *addr; 2051 char hostbuf[8*1024]; 2052 2053// fprintf(stderr, "_gethtent() name = '%s'\n", name); 2054 assert(name != NULL); 2055 assert(pai != NULL); 2056 2057 if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "r" ))) 2058 return (NULL); 2059 again: 2060 if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf))) 2061 return (NULL); 2062 if (*p == '#') 2063 goto again; 2064 if (!(cp = strpbrk(p, "#\n"))) 2065 goto again; 2066 *cp = '\0'; 2067 if (!(cp = strpbrk(p, " \t"))) 2068 goto again; 2069 *cp++ = '\0'; 2070 addr = p; 2071 /* if this is not something we're looking for, skip it. */ 2072 cname = NULL; 2073 while (cp && *cp) { 2074 if (*cp == ' ' || *cp == '\t') { 2075 cp++; 2076 continue; 2077 } 2078 if (!cname) 2079 cname = cp; 2080 tname = cp; 2081 if ((cp = strpbrk(cp, " \t")) != NULL) 2082 *cp++ = '\0'; 2083// fprintf(stderr, "\ttname = '%s'", tname); 2084 if (strcasecmp(name, tname) == 0) 2085 goto found; 2086 } 2087 goto again; 2088 2089found: 2090 hints = *pai; 2091 hints.ai_flags = AI_NUMERICHOST; 2092 error = getaddrinfo(addr, NULL, &hints, &res0); 2093 if (error) 2094 goto again; 2095 for (res = res0; res; res = res->ai_next) { 2096 /* cover it up */ 2097 res->ai_flags = pai->ai_flags; 2098 2099 if (pai->ai_flags & AI_CANONNAME) { 2100 if (get_canonname(pai, res, cname) != 0) { 2101 freeaddrinfo(res0); 2102 goto again; 2103 } 2104 } 2105 } 2106 return res0; 2107} 2108 2109/*ARGSUSED*/ 2110static int 2111_files_getaddrinfo(void *rv, void *cb_data, va_list ap) 2112{ 2113 const char *name; 2114 const struct addrinfo *pai; 2115 struct addrinfo sentinel, *cur; 2116 struct addrinfo *p; 2117 FILE *hostf = NULL; 2118 2119 name = va_arg(ap, char *); 2120 pai = va_arg(ap, struct addrinfo *); 2121 2122// fprintf(stderr, "_files_getaddrinfo() name = '%s'\n", name); 2123 memset(&sentinel, 0, sizeof(sentinel)); 2124 cur = &sentinel; 2125 2126 _sethtent(&hostf); 2127 while ((p = _gethtent(&hostf, name, pai)) != NULL) { 2128 cur->ai_next = p; 2129 while (cur && cur->ai_next) 2130 cur = cur->ai_next; 2131 } 2132 _endhtent(&hostf); 2133 2134 *((struct addrinfo **)rv) = sentinel.ai_next; 2135 if (sentinel.ai_next == NULL) 2136 return NS_NOTFOUND; 2137 return NS_SUCCESS; 2138} 2139 2140/* resolver logic */ 2141 2142/* 2143 * Formulate a normal query, send, and await answer. 2144 * Returned answer is placed in supplied buffer "answer". 2145 * Perform preliminary check of answer, returning success only 2146 * if no error is indicated and the answer count is nonzero. 2147 * Return the size of the response on success, -1 on error. 2148 * Error number is left in h_errno. 2149 * 2150 * Caller must parse answer and determine whether it answers the question. 2151 */ 2152static int 2153res_queryN(const char *name, /* domain name */ struct res_target *target, 2154 res_state res) 2155{ 2156 u_char buf[MAXPACKET]; 2157 HEADER *hp; 2158 int n; 2159 struct res_target *t; 2160 int rcode; 2161 int ancount; 2162 2163 assert(name != NULL); 2164 /* XXX: target may be NULL??? */ 2165 2166 rcode = NOERROR; 2167 ancount = 0; 2168 2169 for (t = target; t; t = t->next) { 2170 int class, type; 2171 u_char *answer; 2172 int anslen; 2173 2174 hp = (HEADER *)(void *)t->answer; 2175 hp->rcode = NOERROR; /* default */ 2176 2177 /* make it easier... */ 2178 class = t->qclass; 2179 type = t->qtype; 2180 answer = t->answer; 2181 anslen = t->anslen; 2182#ifdef DEBUG 2183 if (res->options & RES_DEBUG) 2184 printf(";; res_nquery(%s, %d, %d)\n", name, class, type); 2185#endif 2186 2187 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL, 2188 buf, sizeof(buf)); 2189#ifdef RES_USE_EDNS0 2190 if (n > 0 && (res->options & RES_USE_EDNS0) != 0) 2191 n = res_nopt(res, n, buf, sizeof(buf), anslen); 2192#endif 2193 if (n <= 0) { 2194#ifdef DEBUG 2195 if (res->options & RES_DEBUG) 2196 printf(";; res_nquery: mkquery failed\n"); 2197#endif 2198 h_errno = NO_RECOVERY; 2199 return n; 2200 } 2201 n = res_nsend(res, buf, n, answer, anslen); 2202#if 0 2203 if (n < 0) { 2204#ifdef DEBUG 2205 if (res->options & RES_DEBUG) 2206 printf(";; res_query: send error\n"); 2207#endif 2208 h_errno = TRY_AGAIN; 2209 return n; 2210 } 2211#endif 2212 2213 if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) { 2214 rcode = hp->rcode; /* record most recent error */ 2215#ifdef DEBUG 2216 if (res->options & RES_DEBUG) 2217 printf(";; rcode = %u, ancount=%u\n", hp->rcode, 2218 ntohs(hp->ancount)); 2219#endif 2220 continue; 2221 } 2222 2223 ancount += ntohs(hp->ancount); 2224 2225 t->n = n; 2226 } 2227 2228 if (ancount == 0) { 2229 switch (rcode) { 2230 case NXDOMAIN: 2231 h_errno = HOST_NOT_FOUND; 2232 break; 2233 case SERVFAIL: 2234 h_errno = TRY_AGAIN; 2235 break; 2236 case NOERROR: 2237 h_errno = NO_DATA; 2238 break; 2239 case FORMERR: 2240 case NOTIMP: 2241 case REFUSED: 2242 default: 2243 h_errno = NO_RECOVERY; 2244 break; 2245 } 2246 return -1; 2247 } 2248 return ancount; 2249} 2250 2251/* 2252 * Formulate a normal query, send, and retrieve answer in supplied buffer. 2253 * Return the size of the response on success, -1 on error. 2254 * If enabled, implement search rules until answer or unrecoverable failure 2255 * is detected. Error code, if any, is left in h_errno. 2256 */ 2257static int 2258res_searchN(const char *name, struct res_target *target, res_state res) 2259{ 2260 const char *cp, * const *domain; 2261 HEADER *hp; 2262 u_int dots; 2263 int trailing_dot, ret, saved_herrno; 2264 int got_nodata = 0, got_servfail = 0, tried_as_is = 0; 2265 2266 assert(name != NULL); 2267 assert(target != NULL); 2268 2269 hp = (HEADER *)(void *)target->answer; /*XXX*/ 2270 2271 errno = 0; 2272 h_errno = HOST_NOT_FOUND; /* default, if we never query */ 2273 dots = 0; 2274 for (cp = name; *cp; cp++) 2275 dots += (*cp == '.'); 2276 trailing_dot = 0; 2277 if (cp > name && *--cp == '.') 2278 trailing_dot++; 2279 2280 2281 //fprintf(stderr, "res_searchN() name = '%s'\n", name); 2282 2283 /* 2284 * if there aren't any dots, it could be a user-level alias 2285 */ 2286 if (!dots && (cp = __hostalias(name)) != NULL) { 2287 ret = res_queryN(cp, target, res); 2288 return ret; 2289 } 2290 2291 /* 2292 * If there are dots in the name already, let's just give it a try 2293 * 'as is'. The threshold can be set with the "ndots" option. 2294 */ 2295 saved_herrno = -1; 2296 if (dots >= res->ndots) { 2297 ret = res_querydomainN(name, NULL, target, res); 2298 if (ret > 0) 2299 return (ret); 2300 saved_herrno = h_errno; 2301 tried_as_is++; 2302 } 2303 2304 /* 2305 * We do at least one level of search if 2306 * - there is no dot and RES_DEFNAME is set, or 2307 * - there is at least one dot, there is no trailing dot, 2308 * and RES_DNSRCH is set. 2309 */ 2310 if ((!dots && (res->options & RES_DEFNAMES)) || 2311 (dots && !trailing_dot && (res->options & RES_DNSRCH))) { 2312 int done = 0; 2313 2314 for (domain = (const char * const *)res->dnsrch; 2315 *domain && !done; 2316 domain++) { 2317 2318 ret = res_querydomainN(name, *domain, target, res); 2319 if (ret > 0) 2320 return ret; 2321 2322 /* 2323 * If no server present, give up. 2324 * If name isn't found in this domain, 2325 * keep trying higher domains in the search list 2326 * (if that's enabled). 2327 * On a NO_DATA error, keep trying, otherwise 2328 * a wildcard entry of another type could keep us 2329 * from finding this entry higher in the domain. 2330 * If we get some other error (negative answer or 2331 * server failure), then stop searching up, 2332 * but try the input name below in case it's 2333 * fully-qualified. 2334 */ 2335 if (errno == ECONNREFUSED) { 2336 h_errno = TRY_AGAIN; 2337 return -1; 2338 } 2339 2340 switch (h_errno) { 2341 case NO_DATA: 2342 got_nodata++; 2343 /* FALLTHROUGH */ 2344 case HOST_NOT_FOUND: 2345 /* keep trying */ 2346 break; 2347 case TRY_AGAIN: 2348 if (hp->rcode == SERVFAIL) { 2349 /* try next search element, if any */ 2350 got_servfail++; 2351 break; 2352 } 2353 /* FALLTHROUGH */ 2354 default: 2355 /* anything else implies that we're done */ 2356 done++; 2357 } 2358 /* 2359 * if we got here for some reason other than DNSRCH, 2360 * we only wanted one iteration of the loop, so stop. 2361 */ 2362 if (!(res->options & RES_DNSRCH)) 2363 done++; 2364 } 2365 } 2366 2367 /* 2368 * if we have not already tried the name "as is", do that now. 2369 * note that we do this regardless of how many dots were in the 2370 * name or whether it ends with a dot. 2371 */ 2372 if (!tried_as_is) { 2373 ret = res_querydomainN(name, NULL, target, res); 2374 if (ret > 0) 2375 return ret; 2376 } 2377 2378 /* 2379 * if we got here, we didn't satisfy the search. 2380 * if we did an initial full query, return that query's h_errno 2381 * (note that we wouldn't be here if that query had succeeded). 2382 * else if we ever got a nodata, send that back as the reason. 2383 * else send back meaningless h_errno, that being the one from 2384 * the last DNSRCH we did. 2385 */ 2386 if (saved_herrno != -1) 2387 h_errno = saved_herrno; 2388 else if (got_nodata) 2389 h_errno = NO_DATA; 2390 else if (got_servfail) 2391 h_errno = TRY_AGAIN; 2392 return -1; 2393} 2394 2395/* 2396 * Perform a call on res_query on the concatenation of name and domain, 2397 * removing a trailing dot from name if domain is NULL. 2398 */ 2399static int 2400res_querydomainN(const char *name, const char *domain, 2401 struct res_target *target, res_state res) 2402{ 2403 char nbuf[MAXDNAME]; 2404 const char *longname = nbuf; 2405 size_t n, d; 2406 2407 assert(name != NULL); 2408 /* XXX: target may be NULL??? */ 2409 2410#ifdef DEBUG 2411 if (res->options & RES_DEBUG) 2412 printf(";; res_querydomain(%s, %s)\n", 2413 name, domain?domain:"<Nil>"); 2414#endif 2415 if (domain == NULL) { 2416 /* 2417 * Check for trailing '.'; 2418 * copy without '.' if present. 2419 */ 2420 n = strlen(name); 2421 if (n + 1 > sizeof(nbuf)) { 2422 h_errno = NO_RECOVERY; 2423 return -1; 2424 } 2425 if (n > 0 && name[--n] == '.') { 2426 strncpy(nbuf, name, n); 2427 nbuf[n] = '\0'; 2428 } else 2429 longname = name; 2430 } else { 2431 n = strlen(name); 2432 d = strlen(domain); 2433 if (n + 1 + d + 1 > sizeof(nbuf)) { 2434 h_errno = NO_RECOVERY; 2435 return -1; 2436 } 2437 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain); 2438 } 2439 return res_queryN(longname, target, res); 2440} 2441