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 "NetdClientDispatch.h" 96 #include "resolv_cache.h" 97 #include "resolv_netid.h" 98 #include "resolv_private.h" 99 #include <stdbool.h> 100 #include <stddef.h> 101 #include <stdio.h> 102 #include <stdlib.h> 103 #include <string.h> 104 #include <strings.h> 105 #include <unistd.h> 106 107 #include <syslog.h> 108 #include <stdarg.h> 109 #include "nsswitch.h" 110 111 typedef 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 0 121 122 static const char in_addrany[] = { 0, 0, 0, 0 }; 123 static const char in_loopback[] = { 127, 0, 0, 1 }; 124 #ifdef INET6 125 static const char in6_addrany[] = { 126 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 127 }; 128 static 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 #if defined(__ANDROID__) 134 // This should be synchronized to ResponseCode.h 135 static const int DnsProxyQueryResult = 222; 136 #endif 137 138 static const struct afd { 139 int a_af; 140 int a_addrlen; 141 int a_socklen; 142 int a_off; 143 const char *a_addrany; 144 const char *a_loopback; 145 int a_scoped; 146 } afdl [] = { 147 #ifdef INET6 148 {PF_INET6, sizeof(struct in6_addr), 149 sizeof(struct sockaddr_in6), 150 offsetof(struct sockaddr_in6, sin6_addr), 151 in6_addrany, in6_loopback, 1}, 152 #endif 153 {PF_INET, sizeof(struct in_addr), 154 sizeof(struct sockaddr_in), 155 offsetof(struct sockaddr_in, sin_addr), 156 in_addrany, in_loopback, 0}, 157 {0, 0, 0, 0, NULL, NULL, 0}, 158 }; 159 160 struct explore { 161 int e_af; 162 int e_socktype; 163 int e_protocol; 164 const char *e_protostr; 165 int e_wild; 166 #define WILD_AF(ex) ((ex)->e_wild & 0x01) 167 #define WILD_SOCKTYPE(ex) ((ex)->e_wild & 0x02) 168 #define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04) 169 }; 170 171 static const struct explore explore[] = { 172 #if 0 173 { PF_LOCAL, 0, ANY, ANY, NULL, 0x01 }, 174 #endif 175 #ifdef INET6 176 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, 177 { PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, 178 { PF_INET6, SOCK_RAW, ANY, NULL, 0x05 }, 179 #endif 180 { PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, 181 { PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, 182 { PF_INET, SOCK_RAW, ANY, NULL, 0x05 }, 183 { PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, 184 { PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, 185 { PF_UNSPEC, SOCK_RAW, ANY, NULL, 0x05 }, 186 { -1, 0, 0, NULL, 0 }, 187 }; 188 189 #ifdef INET6 190 #define PTON_MAX 16 191 #else 192 #define PTON_MAX 4 193 #endif 194 195 static const ns_src default_dns_files[] = { 196 { NSSRC_FILES, NS_SUCCESS }, 197 { NSSRC_DNS, NS_SUCCESS }, 198 { 0, 0 } 199 }; 200 201 #define MAXPACKET (64*1024) 202 203 typedef union { 204 HEADER hdr; 205 u_char buf[MAXPACKET]; 206 } querybuf; 207 208 struct res_target { 209 struct res_target *next; 210 const char *name; /* domain name */ 211 int qclass, qtype; /* class and type of query */ 212 u_char *answer; /* buffer to put answer */ 213 int anslen; /* size of answer buffer */ 214 int n; /* result length */ 215 }; 216 217 static int str2number(const char *); 218 static int explore_fqdn(const struct addrinfo *, const char *, 219 const char *, struct addrinfo **, const struct android_net_context *); 220 static int explore_null(const struct addrinfo *, 221 const char *, struct addrinfo **); 222 static int explore_numeric(const struct addrinfo *, const char *, 223 const char *, struct addrinfo **, const char *); 224 static int explore_numeric_scope(const struct addrinfo *, const char *, 225 const char *, struct addrinfo **); 226 static int get_canonname(const struct addrinfo *, 227 struct addrinfo *, const char *); 228 static struct addrinfo *get_ai(const struct addrinfo *, 229 const struct afd *, const char *); 230 static int get_portmatch(const struct addrinfo *, const char *); 231 static int get_port(const struct addrinfo *, const char *, int); 232 static const struct afd *find_afd(int); 233 #ifdef INET6 234 static int ip6_str2scopeid(char *, struct sockaddr_in6 *, u_int32_t *); 235 #endif 236 237 static struct addrinfo *getanswer(const querybuf *, int, const char *, int, 238 const struct addrinfo *); 239 static int _dns_getaddrinfo(void *, void *, va_list); 240 static void _sethtent(FILE **); 241 static void _endhtent(FILE **); 242 static struct addrinfo *_gethtent(FILE **, const char *, 243 const struct addrinfo *); 244 static int _files_getaddrinfo(void *, void *, va_list); 245 static int _find_src_addr(const struct sockaddr *, struct sockaddr *, unsigned , uid_t); 246 247 static int res_queryN(const char *, struct res_target *, res_state); 248 static int res_searchN(const char *, struct res_target *, res_state); 249 static int res_querydomainN(const char *, const char *, 250 struct res_target *, res_state); 251 252 static const char * const ai_errlist[] = { 253 "Success", 254 "Address family for hostname not supported", /* EAI_ADDRFAMILY */ 255 "Temporary failure in name resolution", /* EAI_AGAIN */ 256 "Invalid value for ai_flags", /* EAI_BADFLAGS */ 257 "Non-recoverable failure in name resolution", /* EAI_FAIL */ 258 "ai_family not supported", /* EAI_FAMILY */ 259 "Memory allocation failure", /* EAI_MEMORY */ 260 "No address associated with hostname", /* EAI_NODATA */ 261 "hostname nor servname provided, or not known", /* EAI_NONAME */ 262 "servname not supported for ai_socktype", /* EAI_SERVICE */ 263 "ai_socktype not supported", /* EAI_SOCKTYPE */ 264 "System error returned in errno", /* EAI_SYSTEM */ 265 "Invalid value for hints", /* EAI_BADHINTS */ 266 "Resolved protocol is unknown", /* EAI_PROTOCOL */ 267 "Argument buffer overflow", /* EAI_OVERFLOW */ 268 "Unknown error", /* EAI_MAX */ 269 }; 270 271 /* XXX macros that make external reference is BAD. */ 272 273 #define GET_AI(ai, afd, addr) \ 274 do { \ 275 /* external reference: pai, error, and label free */ \ 276 (ai) = get_ai(pai, (afd), (addr)); \ 277 if ((ai) == NULL) { \ 278 error = EAI_MEMORY; \ 279 goto free; \ 280 } \ 281 } while (/*CONSTCOND*/0) 282 283 #define GET_PORT(ai, serv) \ 284 do { \ 285 /* external reference: error and label free */ \ 286 error = get_port((ai), (serv), 0); \ 287 if (error != 0) \ 288 goto free; \ 289 } while (/*CONSTCOND*/0) 290 291 #define GET_CANONNAME(ai, str) \ 292 do { \ 293 /* external reference: pai, error and label free */ \ 294 error = get_canonname(pai, (ai), (str)); \ 295 if (error != 0) \ 296 goto free; \ 297 } while (/*CONSTCOND*/0) 298 299 #define ERR(err) \ 300 do { \ 301 /* external reference: error, and label bad */ \ 302 error = (err); \ 303 goto bad; \ 304 /*NOTREACHED*/ \ 305 } while (/*CONSTCOND*/0) 306 307 #define MATCH_FAMILY(x, y, w) \ 308 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || \ 309 (y) == PF_UNSPEC))) 310 #define MATCH(x, y, w) \ 311 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY))) 312 313 const char * 314 gai_strerror(int ecode) 315 { 316 if (ecode < 0 || ecode > EAI_MAX) 317 ecode = EAI_MAX; 318 return ai_errlist[ecode]; 319 } 320 321 void 322 freeaddrinfo(struct addrinfo *ai) 323 { 324 struct addrinfo *next; 325 326 #if defined(__BIONIC__) 327 if (ai == NULL) return; 328 #else 329 _DIAGASSERT(ai != NULL); 330 #endif 331 332 do { 333 next = ai->ai_next; 334 if (ai->ai_canonname) 335 free(ai->ai_canonname); 336 /* no need to free(ai->ai_addr) */ 337 free(ai); 338 ai = next; 339 } while (ai); 340 } 341 342 static int 343 str2number(const char *p) 344 { 345 char *ep; 346 unsigned long v; 347 348 assert(p != NULL); 349 350 if (*p == '\0') 351 return -1; 352 ep = NULL; 353 errno = 0; 354 v = strtoul(p, &ep, 10); 355 if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX) 356 return v; 357 else 358 return -1; 359 } 360 361 /* 362 * The following functions determine whether IPv4 or IPv6 connectivity is 363 * available in order to implement AI_ADDRCONFIG. 364 * 365 * Strictly speaking, AI_ADDRCONFIG should not look at whether connectivity is 366 * available, but whether addresses of the specified family are "configured 367 * on the local system". However, bionic doesn't currently support getifaddrs, 368 * so checking for connectivity is the next best thing. 369 */ 370 static int 371 _have_ipv6(unsigned mark, uid_t uid) { 372 static const struct sockaddr_in6 sin6_test = { 373 .sin6_family = AF_INET6, 374 .sin6_addr.s6_addr = { // 2000:: 375 0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} 376 }; 377 sockaddr_union addr = { .in6 = sin6_test }; 378 return _find_src_addr(&addr.generic, NULL, mark, uid) == 1; 379 } 380 381 static int 382 _have_ipv4(unsigned mark, uid_t uid) { 383 static const struct sockaddr_in sin_test = { 384 .sin_family = AF_INET, 385 .sin_addr.s_addr = __constant_htonl(0x08080808L) // 8.8.8.8 386 }; 387 sockaddr_union addr = { .in = sin_test }; 388 return _find_src_addr(&addr.generic, NULL, mark, uid) == 1; 389 } 390 391 bool readBE32(FILE* fp, int32_t* result) { 392 int32_t tmp; 393 if (fread(&tmp, sizeof(tmp), 1, fp) != 1) { 394 return false; 395 } 396 *result = ntohl(tmp); 397 return true; 398 } 399 400 #if defined(__ANDROID__) 401 // Returns 0 on success, else returns on error. 402 static int 403 android_getaddrinfo_proxy( 404 const char *hostname, const char *servname, 405 const struct addrinfo *hints, struct addrinfo **res, unsigned netid) 406 { 407 int success = 0; 408 409 // Clear this at start, as we use its non-NULLness later (in the 410 // error path) to decide if we have to free up any memory we 411 // allocated in the process (before failing). 412 *res = NULL; 413 414 // Bogus things we can't serialize. Don't use the proxy. These will fail - let them. 415 if ((hostname != NULL && 416 strcspn(hostname, " \n\r\t^'\"") != strlen(hostname)) || 417 (servname != NULL && 418 strcspn(servname, " \n\r\t^'\"") != strlen(servname))) { 419 return EAI_NODATA; 420 } 421 422 FILE* proxy = android_open_proxy(); 423 if (proxy == NULL) { 424 return EAI_SYSTEM; 425 } 426 427 netid = __netdClientDispatch.netIdForResolv(netid); 428 429 // Send the request. 430 if (fprintf(proxy, "getaddrinfo %s %s %d %d %d %d %u", 431 hostname == NULL ? "^" : hostname, 432 servname == NULL ? "^" : servname, 433 hints == NULL ? -1 : hints->ai_flags, 434 hints == NULL ? -1 : hints->ai_family, 435 hints == NULL ? -1 : hints->ai_socktype, 436 hints == NULL ? -1 : hints->ai_protocol, 437 netid) < 0) { 438 goto exit; 439 } 440 // literal NULL byte at end, required by FrameworkListener 441 if (fputc(0, proxy) == EOF || 442 fflush(proxy) != 0) { 443 goto exit; 444 } 445 446 char buf[4]; 447 // read result code for gethostbyaddr 448 if (fread(buf, 1, sizeof(buf), proxy) != sizeof(buf)) { 449 goto exit; 450 } 451 452 int result_code = (int)strtol(buf, NULL, 10); 453 // verify the code itself 454 if (result_code != DnsProxyQueryResult) { 455 fread(buf, 1, sizeof(buf), proxy); 456 goto exit; 457 } 458 459 struct addrinfo* ai = NULL; 460 struct addrinfo** nextres = res; 461 while (1) { 462 int32_t have_more; 463 if (!readBE32(proxy, &have_more)) { 464 break; 465 } 466 if (have_more == 0) { 467 success = 1; 468 break; 469 } 470 471 struct addrinfo* ai = calloc(1, sizeof(struct addrinfo) + sizeof(struct sockaddr_storage)); 472 if (ai == NULL) { 473 break; 474 } 475 ai->ai_addr = (struct sockaddr*)(ai + 1); 476 477 // struct addrinfo { 478 // int ai_flags; /* AI_PASSIVE, AI_CANONNAME, AI_NUMERICHOST */ 479 // int ai_family; /* PF_xxx */ 480 // int ai_socktype; /* SOCK_xxx */ 481 // int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */ 482 // socklen_t ai_addrlen; /* length of ai_addr */ 483 // char *ai_canonname; /* canonical name for hostname */ 484 // struct sockaddr *ai_addr; /* binary address */ 485 // struct addrinfo *ai_next; /* next structure in linked list */ 486 // }; 487 488 // Read the struct piece by piece because we might be a 32-bit process 489 // talking to a 64-bit netd. 490 int32_t addr_len; 491 bool success = 492 readBE32(proxy, &ai->ai_flags) && 493 readBE32(proxy, &ai->ai_family) && 494 readBE32(proxy, &ai->ai_socktype) && 495 readBE32(proxy, &ai->ai_protocol) && 496 readBE32(proxy, &addr_len); 497 if (!success) { 498 break; 499 } 500 501 // Set ai_addrlen and read the ai_addr data. 502 ai->ai_addrlen = addr_len; 503 if (addr_len != 0) { 504 if ((size_t) addr_len > sizeof(struct sockaddr_storage)) { 505 // Bogus; too big. 506 break; 507 } 508 if (fread(ai->ai_addr, addr_len, 1, proxy) != 1) { 509 break; 510 } 511 } 512 513 // The string for ai_cannonname. 514 int32_t name_len; 515 if (!readBE32(proxy, &name_len)) { 516 break; 517 } 518 if (name_len != 0) { 519 ai->ai_canonname = (char*) malloc(name_len); 520 if (fread(ai->ai_canonname, name_len, 1, proxy) != 1) { 521 break; 522 } 523 if (ai->ai_canonname[name_len - 1] != '\0') { 524 // The proxy should be returning this 525 // NULL-terminated. 526 break; 527 } 528 } 529 530 *nextres = ai; 531 nextres = &ai->ai_next; 532 ai = NULL; 533 } 534 535 if (ai != NULL) { 536 // Clean up partially-built addrinfo that we never ended up 537 // attaching to the response. 538 freeaddrinfo(ai); 539 } 540 exit: 541 if (proxy != NULL) { 542 fclose(proxy); 543 } 544 545 if (success) { 546 return 0; 547 } 548 549 // Proxy failed; 550 // clean up memory we might've allocated. 551 if (*res) { 552 freeaddrinfo(*res); 553 *res = NULL; 554 } 555 return EAI_NODATA; 556 } 557 #endif 558 559 int 560 getaddrinfo(const char *hostname, const char *servname, 561 const struct addrinfo *hints, struct addrinfo **res) 562 { 563 return android_getaddrinfofornet(hostname, servname, hints, NETID_UNSET, MARK_UNSET, res); 564 } 565 566 int 567 android_getaddrinfofornet(const char *hostname, const char *servname, 568 const struct addrinfo *hints, unsigned netid, unsigned mark, struct addrinfo **res) 569 { 570 struct android_net_context netcontext = { 571 .app_netid = netid, 572 .app_mark = mark, 573 .dns_netid = netid, 574 .dns_mark = mark, 575 .uid = NET_CONTEXT_INVALID_UID, 576 }; 577 return android_getaddrinfofornetcontext(hostname, servname, hints, &netcontext, res); 578 } 579 580 int 581 android_getaddrinfofornetcontext(const char *hostname, const char *servname, 582 const struct addrinfo *hints, const struct android_net_context *netcontext, 583 struct addrinfo **res) 584 { 585 struct addrinfo sentinel; 586 struct addrinfo *cur; 587 int error = 0; 588 struct addrinfo ai; 589 struct addrinfo ai0; 590 struct addrinfo *pai; 591 const struct explore *ex; 592 593 /* hostname is allowed to be NULL */ 594 /* servname is allowed to be NULL */ 595 /* hints is allowed to be NULL */ 596 assert(res != NULL); 597 assert(netcontext != NULL); 598 memset(&sentinel, 0, sizeof(sentinel)); 599 cur = &sentinel; 600 pai = &ai; 601 pai->ai_flags = 0; 602 pai->ai_family = PF_UNSPEC; 603 pai->ai_socktype = ANY; 604 pai->ai_protocol = ANY; 605 pai->ai_addrlen = 0; 606 pai->ai_canonname = NULL; 607 pai->ai_addr = NULL; 608 pai->ai_next = NULL; 609 610 if (hostname == NULL && servname == NULL) 611 return EAI_NONAME; 612 if (hints) { 613 /* error check for hints */ 614 if (hints->ai_addrlen || hints->ai_canonname || 615 hints->ai_addr || hints->ai_next) 616 ERR(EAI_BADHINTS); /* xxx */ 617 if (hints->ai_flags & ~AI_MASK) 618 ERR(EAI_BADFLAGS); 619 switch (hints->ai_family) { 620 case PF_UNSPEC: 621 case PF_INET: 622 #ifdef INET6 623 case PF_INET6: 624 #endif 625 break; 626 default: 627 ERR(EAI_FAMILY); 628 } 629 memcpy(pai, hints, sizeof(*pai)); 630 631 /* 632 * if both socktype/protocol are specified, check if they 633 * are meaningful combination. 634 */ 635 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) { 636 for (ex = explore; ex->e_af >= 0; ex++) { 637 if (pai->ai_family != ex->e_af) 638 continue; 639 if (ex->e_socktype == ANY) 640 continue; 641 if (ex->e_protocol == ANY) 642 continue; 643 if (pai->ai_socktype == ex->e_socktype 644 && pai->ai_protocol != ex->e_protocol) { 645 ERR(EAI_BADHINTS); 646 } 647 } 648 } 649 } 650 651 /* 652 * check for special cases. (1) numeric servname is disallowed if 653 * socktype/protocol are left unspecified. (2) servname is disallowed 654 * for raw and other inet{,6} sockets. 655 */ 656 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1) 657 #ifdef PF_INET6 658 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1) 659 #endif 660 ) { 661 ai0 = *pai; /* backup *pai */ 662 663 if (pai->ai_family == PF_UNSPEC) { 664 #ifdef PF_INET6 665 pai->ai_family = PF_INET6; 666 #else 667 pai->ai_family = PF_INET; 668 #endif 669 } 670 error = get_portmatch(pai, servname); 671 if (error) 672 ERR(error); 673 674 *pai = ai0; 675 } 676 677 ai0 = *pai; 678 679 /* NULL hostname, or numeric hostname */ 680 for (ex = explore; ex->e_af >= 0; ex++) { 681 *pai = ai0; 682 683 /* PF_UNSPEC entries are prepared for DNS queries only */ 684 if (ex->e_af == PF_UNSPEC) 685 continue; 686 687 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex))) 688 continue; 689 if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex))) 690 continue; 691 if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex))) 692 continue; 693 694 if (pai->ai_family == PF_UNSPEC) 695 pai->ai_family = ex->e_af; 696 if (pai->ai_socktype == ANY && ex->e_socktype != ANY) 697 pai->ai_socktype = ex->e_socktype; 698 if (pai->ai_protocol == ANY && ex->e_protocol != ANY) 699 pai->ai_protocol = ex->e_protocol; 700 701 if (hostname == NULL) 702 error = explore_null(pai, servname, &cur->ai_next); 703 else 704 error = explore_numeric_scope(pai, hostname, servname, 705 &cur->ai_next); 706 707 if (error) 708 goto free; 709 710 while (cur->ai_next) 711 cur = cur->ai_next; 712 } 713 714 /* 715 * XXX 716 * If numeric representation of AF1 can be interpreted as FQDN 717 * representation of AF2, we need to think again about the code below. 718 */ 719 if (sentinel.ai_next) 720 goto good; 721 722 if (hostname == NULL) 723 ERR(EAI_NODATA); 724 if (pai->ai_flags & AI_NUMERICHOST) 725 ERR(EAI_NONAME); 726 727 #if defined(__ANDROID__) 728 int gai_error = android_getaddrinfo_proxy( 729 hostname, servname, hints, res, netcontext->app_netid); 730 if (gai_error != EAI_SYSTEM) { 731 return gai_error; 732 } 733 #endif 734 735 /* 736 * hostname as alphabetical name. 737 * we would like to prefer AF_INET6 than AF_INET, so we'll make a 738 * outer loop by AFs. 739 */ 740 for (ex = explore; ex->e_af >= 0; ex++) { 741 *pai = ai0; 742 743 /* require exact match for family field */ 744 if (pai->ai_family != ex->e_af) 745 continue; 746 747 if (!MATCH(pai->ai_socktype, ex->e_socktype, 748 WILD_SOCKTYPE(ex))) { 749 continue; 750 } 751 if (!MATCH(pai->ai_protocol, ex->e_protocol, 752 WILD_PROTOCOL(ex))) { 753 continue; 754 } 755 756 if (pai->ai_socktype == ANY && ex->e_socktype != ANY) 757 pai->ai_socktype = ex->e_socktype; 758 if (pai->ai_protocol == ANY && ex->e_protocol != ANY) 759 pai->ai_protocol = ex->e_protocol; 760 761 error = explore_fqdn( 762 pai, hostname, servname, &cur->ai_next, netcontext); 763 764 while (cur && cur->ai_next) 765 cur = cur->ai_next; 766 } 767 768 /* XXX */ 769 if (sentinel.ai_next) 770 error = 0; 771 772 if (error) 773 goto free; 774 if (error == 0) { 775 if (sentinel.ai_next) { 776 good: 777 *res = sentinel.ai_next; 778 return SUCCESS; 779 } else 780 error = EAI_FAIL; 781 } 782 free: 783 bad: 784 if (sentinel.ai_next) 785 freeaddrinfo(sentinel.ai_next); 786 *res = NULL; 787 return error; 788 } 789 790 /* 791 * FQDN hostname, DNS lookup 792 */ 793 static int 794 explore_fqdn(const struct addrinfo *pai, const char *hostname, 795 const char *servname, struct addrinfo **res, 796 const struct android_net_context *netcontext) 797 { 798 struct addrinfo *result; 799 struct addrinfo *cur; 800 int error = 0; 801 static const ns_dtab dtab[] = { 802 NS_FILES_CB(_files_getaddrinfo, NULL) 803 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */ 804 NS_NIS_CB(_yp_getaddrinfo, NULL) 805 { 0, 0, 0 } 806 }; 807 808 assert(pai != NULL); 809 /* hostname may be NULL */ 810 /* servname may be NULL */ 811 assert(res != NULL); 812 813 result = NULL; 814 815 /* 816 * if the servname does not match socktype/protocol, ignore it. 817 */ 818 if (get_portmatch(pai, servname) != 0) 819 return 0; 820 821 switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo", 822 default_dns_files, hostname, pai, netcontext)) { 823 case NS_TRYAGAIN: 824 error = EAI_AGAIN; 825 goto free; 826 case NS_UNAVAIL: 827 error = EAI_FAIL; 828 goto free; 829 case NS_NOTFOUND: 830 error = EAI_NODATA; 831 goto free; 832 case NS_SUCCESS: 833 error = 0; 834 for (cur = result; cur; cur = cur->ai_next) { 835 GET_PORT(cur, servname); 836 /* canonname should be filled already */ 837 } 838 break; 839 } 840 841 *res = result; 842 843 return 0; 844 845 free: 846 if (result) 847 freeaddrinfo(result); 848 return error; 849 } 850 851 /* 852 * hostname == NULL. 853 * passive socket -> anyaddr (0.0.0.0 or ::) 854 * non-passive socket -> localhost (127.0.0.1 or ::1) 855 */ 856 static int 857 explore_null(const struct addrinfo *pai, const char *servname, 858 struct addrinfo **res) 859 { 860 int s; 861 const struct afd *afd; 862 struct addrinfo *cur; 863 struct addrinfo sentinel; 864 int error; 865 866 assert(pai != NULL); 867 /* servname may be NULL */ 868 assert(res != NULL); 869 870 *res = NULL; 871 sentinel.ai_next = NULL; 872 cur = &sentinel; 873 874 /* 875 * filter out AFs that are not supported by the kernel 876 * XXX errno? 877 */ 878 s = socket(pai->ai_family, SOCK_DGRAM | SOCK_CLOEXEC, 0); 879 if (s < 0) { 880 if (errno != EMFILE) 881 return 0; 882 } else 883 close(s); 884 885 /* 886 * if the servname does not match socktype/protocol, ignore it. 887 */ 888 if (get_portmatch(pai, servname) != 0) 889 return 0; 890 891 afd = find_afd(pai->ai_family); 892 if (afd == NULL) 893 return 0; 894 895 if (pai->ai_flags & AI_PASSIVE) { 896 GET_AI(cur->ai_next, afd, afd->a_addrany); 897 /* xxx meaningless? 898 * GET_CANONNAME(cur->ai_next, "anyaddr"); 899 */ 900 GET_PORT(cur->ai_next, servname); 901 } else { 902 GET_AI(cur->ai_next, afd, afd->a_loopback); 903 /* xxx meaningless? 904 * GET_CANONNAME(cur->ai_next, "localhost"); 905 */ 906 GET_PORT(cur->ai_next, servname); 907 } 908 cur = cur->ai_next; 909 910 *res = sentinel.ai_next; 911 return 0; 912 913 free: 914 if (sentinel.ai_next) 915 freeaddrinfo(sentinel.ai_next); 916 return error; 917 } 918 919 /* 920 * numeric hostname 921 */ 922 static int 923 explore_numeric(const struct addrinfo *pai, const char *hostname, 924 const char *servname, struct addrinfo **res, const char *canonname) 925 { 926 const struct afd *afd; 927 struct addrinfo *cur; 928 struct addrinfo sentinel; 929 int error; 930 char pton[PTON_MAX]; 931 932 assert(pai != NULL); 933 /* hostname may be NULL */ 934 /* servname may be NULL */ 935 assert(res != NULL); 936 937 *res = NULL; 938 sentinel.ai_next = NULL; 939 cur = &sentinel; 940 941 /* 942 * if the servname does not match socktype/protocol, ignore it. 943 */ 944 if (get_portmatch(pai, servname) != 0) 945 return 0; 946 947 afd = find_afd(pai->ai_family); 948 if (afd == NULL) 949 return 0; 950 951 switch (afd->a_af) { 952 #if 0 /*X/Open spec*/ 953 case AF_INET: 954 if (inet_aton(hostname, (struct in_addr *)pton) == 1) { 955 if (pai->ai_family == afd->a_af || 956 pai->ai_family == PF_UNSPEC /*?*/) { 957 GET_AI(cur->ai_next, afd, pton); 958 GET_PORT(cur->ai_next, servname); 959 if ((pai->ai_flags & AI_CANONNAME)) { 960 /* 961 * Set the numeric address itself as 962 * the canonical name, based on a 963 * clarification in rfc2553bis-03. 964 */ 965 GET_CANONNAME(cur->ai_next, canonname); 966 } 967 while (cur && cur->ai_next) 968 cur = cur->ai_next; 969 } else 970 ERR(EAI_FAMILY); /*xxx*/ 971 } 972 break; 973 #endif 974 default: 975 if (inet_pton(afd->a_af, hostname, pton) == 1) { 976 if (pai->ai_family == afd->a_af || 977 pai->ai_family == PF_UNSPEC /*?*/) { 978 GET_AI(cur->ai_next, afd, pton); 979 GET_PORT(cur->ai_next, servname); 980 if ((pai->ai_flags & AI_CANONNAME)) { 981 /* 982 * Set the numeric address itself as 983 * the canonical name, based on a 984 * clarification in rfc2553bis-03. 985 */ 986 GET_CANONNAME(cur->ai_next, canonname); 987 } 988 while (cur->ai_next) 989 cur = cur->ai_next; 990 } else 991 ERR(EAI_FAMILY); /*xxx*/ 992 } 993 break; 994 } 995 996 *res = sentinel.ai_next; 997 return 0; 998 999 free: 1000 bad: 1001 if (sentinel.ai_next) 1002 freeaddrinfo(sentinel.ai_next); 1003 return error; 1004 } 1005 1006 /* 1007 * numeric hostname with scope 1008 */ 1009 static int 1010 explore_numeric_scope(const struct addrinfo *pai, const char *hostname, 1011 const char *servname, struct addrinfo **res) 1012 { 1013 #if !defined(SCOPE_DELIMITER) || !defined(INET6) 1014 return explore_numeric(pai, hostname, servname, res, hostname); 1015 #else 1016 const struct afd *afd; 1017 struct addrinfo *cur; 1018 int error; 1019 char *cp, *hostname2 = NULL, *scope, *addr; 1020 struct sockaddr_in6 *sin6; 1021 1022 assert(pai != NULL); 1023 /* hostname may be NULL */ 1024 /* servname may be NULL */ 1025 assert(res != NULL); 1026 1027 /* 1028 * if the servname does not match socktype/protocol, ignore it. 1029 */ 1030 if (get_portmatch(pai, servname) != 0) 1031 return 0; 1032 1033 afd = find_afd(pai->ai_family); 1034 if (afd == NULL) 1035 return 0; 1036 1037 if (!afd->a_scoped) 1038 return explore_numeric(pai, hostname, servname, res, hostname); 1039 1040 cp = strchr(hostname, SCOPE_DELIMITER); 1041 if (cp == NULL) 1042 return explore_numeric(pai, hostname, servname, res, hostname); 1043 1044 /* 1045 * Handle special case of <scoped_address><delimiter><scope id> 1046 */ 1047 hostname2 = strdup(hostname); 1048 if (hostname2 == NULL) 1049 return EAI_MEMORY; 1050 /* terminate at the delimiter */ 1051 hostname2[cp - hostname] = '\0'; 1052 addr = hostname2; 1053 scope = cp + 1; 1054 1055 error = explore_numeric(pai, addr, servname, res, hostname); 1056 if (error == 0) { 1057 u_int32_t scopeid; 1058 1059 for (cur = *res; cur; cur = cur->ai_next) { 1060 if (cur->ai_family != AF_INET6) 1061 continue; 1062 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr; 1063 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) { 1064 free(hostname2); 1065 return(EAI_NODATA); /* XXX: is return OK? */ 1066 } 1067 sin6->sin6_scope_id = scopeid; 1068 } 1069 } 1070 1071 free(hostname2); 1072 1073 return error; 1074 #endif 1075 } 1076 1077 static int 1078 get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str) 1079 { 1080 1081 assert(pai != NULL); 1082 assert(ai != NULL); 1083 assert(str != NULL); 1084 1085 if ((pai->ai_flags & AI_CANONNAME) != 0) { 1086 ai->ai_canonname = strdup(str); 1087 if (ai->ai_canonname == NULL) 1088 return EAI_MEMORY; 1089 } 1090 return 0; 1091 } 1092 1093 static struct addrinfo * 1094 get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr) 1095 { 1096 char *p; 1097 struct addrinfo *ai; 1098 1099 assert(pai != NULL); 1100 assert(afd != NULL); 1101 assert(addr != NULL); 1102 1103 ai = (struct addrinfo *)malloc(sizeof(struct addrinfo) 1104 + (afd->a_socklen)); 1105 if (ai == NULL) 1106 return NULL; 1107 1108 memcpy(ai, pai, sizeof(struct addrinfo)); 1109 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1); 1110 memset(ai->ai_addr, 0, (size_t)afd->a_socklen); 1111 1112 #ifdef HAVE_SA_LEN 1113 ai->ai_addr->sa_len = afd->a_socklen; 1114 #endif 1115 1116 ai->ai_addrlen = afd->a_socklen; 1117 #if defined (__alpha__) || (defined(__i386__) && defined(_LP64)) || defined(__sparc64__) 1118 ai->__ai_pad0 = 0; 1119 #endif 1120 ai->ai_addr->sa_family = ai->ai_family = afd->a_af; 1121 p = (char *)(void *)(ai->ai_addr); 1122 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen); 1123 return ai; 1124 } 1125 1126 static int 1127 get_portmatch(const struct addrinfo *ai, const char *servname) 1128 { 1129 1130 assert(ai != NULL); 1131 /* servname may be NULL */ 1132 1133 return get_port(ai, servname, 1); 1134 } 1135 1136 static int 1137 get_port(const struct addrinfo *ai, const char *servname, int matchonly) 1138 { 1139 const char *proto; 1140 struct servent *sp; 1141 int port; 1142 int allownumeric; 1143 1144 assert(ai != NULL); 1145 /* servname may be NULL */ 1146 1147 if (servname == NULL) 1148 return 0; 1149 switch (ai->ai_family) { 1150 case AF_INET: 1151 #ifdef AF_INET6 1152 case AF_INET6: 1153 #endif 1154 break; 1155 default: 1156 return 0; 1157 } 1158 1159 switch (ai->ai_socktype) { 1160 case SOCK_RAW: 1161 return EAI_SERVICE; 1162 case SOCK_DGRAM: 1163 case SOCK_STREAM: 1164 allownumeric = 1; 1165 break; 1166 case ANY: 1167 #if 1 /* ANDROID-SPECIFIC CHANGE TO MATCH GLIBC */ 1168 allownumeric = 1; 1169 #else 1170 allownumeric = 0; 1171 #endif 1172 break; 1173 default: 1174 return EAI_SOCKTYPE; 1175 } 1176 1177 port = str2number(servname); 1178 if (port >= 0) { 1179 if (!allownumeric) 1180 return EAI_SERVICE; 1181 if (port < 0 || port > 65535) 1182 return EAI_SERVICE; 1183 port = htons(port); 1184 } else { 1185 if (ai->ai_flags & AI_NUMERICSERV) 1186 return EAI_NONAME; 1187 1188 switch (ai->ai_socktype) { 1189 case SOCK_DGRAM: 1190 proto = "udp"; 1191 break; 1192 case SOCK_STREAM: 1193 proto = "tcp"; 1194 break; 1195 default: 1196 proto = NULL; 1197 break; 1198 } 1199 1200 if ((sp = getservbyname(servname, proto)) == NULL) 1201 return EAI_SERVICE; 1202 port = sp->s_port; 1203 } 1204 1205 if (!matchonly) { 1206 switch (ai->ai_family) { 1207 case AF_INET: 1208 ((struct sockaddr_in *)(void *) 1209 ai->ai_addr)->sin_port = port; 1210 break; 1211 #ifdef INET6 1212 case AF_INET6: 1213 ((struct sockaddr_in6 *)(void *) 1214 ai->ai_addr)->sin6_port = port; 1215 break; 1216 #endif 1217 } 1218 } 1219 1220 return 0; 1221 } 1222 1223 static const struct afd * 1224 find_afd(int af) 1225 { 1226 const struct afd *afd; 1227 1228 if (af == PF_UNSPEC) 1229 return NULL; 1230 for (afd = afdl; afd->a_af; afd++) { 1231 if (afd->a_af == af) 1232 return afd; 1233 } 1234 return NULL; 1235 } 1236 1237 #ifdef INET6 1238 /* convert a string to a scope identifier. XXX: IPv6 specific */ 1239 static int 1240 ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid) 1241 { 1242 u_long lscopeid; 1243 struct in6_addr *a6; 1244 char *ep; 1245 1246 assert(scope != NULL); 1247 assert(sin6 != NULL); 1248 assert(scopeid != NULL); 1249 1250 a6 = &sin6->sin6_addr; 1251 1252 /* empty scopeid portion is invalid */ 1253 if (*scope == '\0') 1254 return -1; 1255 1256 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) { 1257 /* 1258 * We currently assume a one-to-one mapping between links 1259 * and interfaces, so we simply use interface indices for 1260 * like-local scopes. 1261 */ 1262 *scopeid = if_nametoindex(scope); 1263 if (*scopeid == 0) 1264 goto trynumeric; 1265 return 0; 1266 } 1267 1268 /* still unclear about literal, allow numeric only - placeholder */ 1269 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6)) 1270 goto trynumeric; 1271 if (IN6_IS_ADDR_MC_ORGLOCAL(a6)) 1272 goto trynumeric; 1273 else 1274 goto trynumeric; /* global */ 1275 1276 /* try to convert to a numeric id as a last resort */ 1277 trynumeric: 1278 errno = 0; 1279 lscopeid = strtoul(scope, &ep, 10); 1280 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL); 1281 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid) 1282 return 0; 1283 else 1284 return -1; 1285 } 1286 #endif 1287 1288 /* code duplicate with gethnamaddr.c */ 1289 1290 static const char AskedForGot[] = 1291 "gethostby*.getanswer: asked for \"%s\", got \"%s\""; 1292 1293 #define BOUNDED_INCR(x) \ 1294 do { \ 1295 BOUNDS_CHECK(cp, x); \ 1296 cp += (x); \ 1297 } while (/*CONSTCOND*/0) 1298 1299 #define BOUNDS_CHECK(ptr, count) \ 1300 do { \ 1301 if (eom - (ptr) < (count)) { h_errno = NO_RECOVERY; return NULL; } \ 1302 } while (/*CONSTCOND*/0) 1303 1304 static struct addrinfo * 1305 getanswer(const querybuf *answer, int anslen, const char *qname, int qtype, 1306 const struct addrinfo *pai) 1307 { 1308 struct addrinfo sentinel, *cur; 1309 struct addrinfo ai; 1310 const struct afd *afd; 1311 char *canonname; 1312 const HEADER *hp; 1313 const u_char *cp; 1314 int n; 1315 const u_char *eom; 1316 char *bp, *ep; 1317 int type, class, ancount, qdcount; 1318 int haveanswer, had_error; 1319 char tbuf[MAXDNAME]; 1320 int (*name_ok) (const char *); 1321 char hostbuf[8*1024]; 1322 1323 assert(answer != NULL); 1324 assert(qname != NULL); 1325 assert(pai != NULL); 1326 1327 memset(&sentinel, 0, sizeof(sentinel)); 1328 cur = &sentinel; 1329 1330 canonname = NULL; 1331 eom = answer->buf + anslen; 1332 switch (qtype) { 1333 case T_A: 1334 case T_AAAA: 1335 case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/ 1336 name_ok = res_hnok; 1337 break; 1338 default: 1339 return NULL; /* XXX should be abort(); */ 1340 } 1341 /* 1342 * find first satisfactory answer 1343 */ 1344 hp = &answer->hdr; 1345 ancount = ntohs(hp->ancount); 1346 qdcount = ntohs(hp->qdcount); 1347 bp = hostbuf; 1348 ep = hostbuf + sizeof hostbuf; 1349 cp = answer->buf; 1350 BOUNDED_INCR(HFIXEDSZ); 1351 if (qdcount != 1) { 1352 h_errno = NO_RECOVERY; 1353 return (NULL); 1354 } 1355 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 1356 if ((n < 0) || !(*name_ok)(bp)) { 1357 h_errno = NO_RECOVERY; 1358 return (NULL); 1359 } 1360 BOUNDED_INCR(n + QFIXEDSZ); 1361 if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) { 1362 /* res_send() has already verified that the query name is the 1363 * same as the one we sent; this just gets the expanded name 1364 * (i.e., with the succeeding search-domain tacked on). 1365 */ 1366 n = strlen(bp) + 1; /* for the \0 */ 1367 if (n >= MAXHOSTNAMELEN) { 1368 h_errno = NO_RECOVERY; 1369 return (NULL); 1370 } 1371 canonname = bp; 1372 bp += n; 1373 /* The qname can be abbreviated, but h_name is now absolute. */ 1374 qname = canonname; 1375 } 1376 haveanswer = 0; 1377 had_error = 0; 1378 while (ancount-- > 0 && cp < eom && !had_error) { 1379 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 1380 if ((n < 0) || !(*name_ok)(bp)) { 1381 had_error++; 1382 continue; 1383 } 1384 cp += n; /* name */ 1385 BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ); 1386 type = _getshort(cp); 1387 cp += INT16SZ; /* type */ 1388 class = _getshort(cp); 1389 cp += INT16SZ + INT32SZ; /* class, TTL */ 1390 n = _getshort(cp); 1391 cp += INT16SZ; /* len */ 1392 BOUNDS_CHECK(cp, n); 1393 if (class != C_IN) { 1394 /* XXX - debug? syslog? */ 1395 cp += n; 1396 continue; /* XXX - had_error++ ? */ 1397 } 1398 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) && 1399 type == T_CNAME) { 1400 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); 1401 if ((n < 0) || !(*name_ok)(tbuf)) { 1402 had_error++; 1403 continue; 1404 } 1405 cp += n; 1406 /* Get canonical name. */ 1407 n = strlen(tbuf) + 1; /* for the \0 */ 1408 if (n > ep - bp || n >= MAXHOSTNAMELEN) { 1409 had_error++; 1410 continue; 1411 } 1412 strlcpy(bp, tbuf, (size_t)(ep - bp)); 1413 canonname = bp; 1414 bp += n; 1415 continue; 1416 } 1417 if (qtype == T_ANY) { 1418 if (!(type == T_A || type == T_AAAA)) { 1419 cp += n; 1420 continue; 1421 } 1422 } else if (type != qtype) { 1423 if (type != T_KEY && type != T_SIG) 1424 syslog(LOG_NOTICE|LOG_AUTH, 1425 "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"", 1426 qname, p_class(C_IN), p_type(qtype), 1427 p_type(type)); 1428 cp += n; 1429 continue; /* XXX - had_error++ ? */ 1430 } 1431 switch (type) { 1432 case T_A: 1433 case T_AAAA: 1434 if (strcasecmp(canonname, bp) != 0) { 1435 syslog(LOG_NOTICE|LOG_AUTH, 1436 AskedForGot, canonname, bp); 1437 cp += n; 1438 continue; /* XXX - had_error++ ? */ 1439 } 1440 if (type == T_A && n != INADDRSZ) { 1441 cp += n; 1442 continue; 1443 } 1444 if (type == T_AAAA && n != IN6ADDRSZ) { 1445 cp += n; 1446 continue; 1447 } 1448 if (type == T_AAAA) { 1449 struct in6_addr in6; 1450 memcpy(&in6, cp, IN6ADDRSZ); 1451 if (IN6_IS_ADDR_V4MAPPED(&in6)) { 1452 cp += n; 1453 continue; 1454 } 1455 } 1456 if (!haveanswer) { 1457 int nn; 1458 1459 canonname = bp; 1460 nn = strlen(bp) + 1; /* for the \0 */ 1461 bp += nn; 1462 } 1463 1464 /* don't overwrite pai */ 1465 ai = *pai; 1466 ai.ai_family = (type == T_A) ? AF_INET : AF_INET6; 1467 afd = find_afd(ai.ai_family); 1468 if (afd == NULL) { 1469 cp += n; 1470 continue; 1471 } 1472 cur->ai_next = get_ai(&ai, afd, (const char *)cp); 1473 if (cur->ai_next == NULL) 1474 had_error++; 1475 while (cur && cur->ai_next) 1476 cur = cur->ai_next; 1477 cp += n; 1478 break; 1479 default: 1480 abort(); 1481 } 1482 if (!had_error) 1483 haveanswer++; 1484 } 1485 if (haveanswer) { 1486 if (!canonname) 1487 (void)get_canonname(pai, sentinel.ai_next, qname); 1488 else 1489 (void)get_canonname(pai, sentinel.ai_next, canonname); 1490 h_errno = NETDB_SUCCESS; 1491 return sentinel.ai_next; 1492 } 1493 1494 h_errno = NO_RECOVERY; 1495 return NULL; 1496 } 1497 1498 struct addrinfo_sort_elem { 1499 struct addrinfo *ai; 1500 int has_src_addr; 1501 sockaddr_union src_addr; 1502 int original_order; 1503 }; 1504 1505 /*ARGSUSED*/ 1506 static int 1507 _get_scope(const struct sockaddr *addr) 1508 { 1509 if (addr->sa_family == AF_INET6) { 1510 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr; 1511 if (IN6_IS_ADDR_MULTICAST(&addr6->sin6_addr)) { 1512 return IPV6_ADDR_MC_SCOPE(&addr6->sin6_addr); 1513 } else if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr) || 1514 IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr)) { 1515 /* 1516 * RFC 4291 section 2.5.3 says loopback is to be treated as having 1517 * link-local scope. 1518 */ 1519 return IPV6_ADDR_SCOPE_LINKLOCAL; 1520 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) { 1521 return IPV6_ADDR_SCOPE_SITELOCAL; 1522 } else { 1523 return IPV6_ADDR_SCOPE_GLOBAL; 1524 } 1525 } else if (addr->sa_family == AF_INET) { 1526 const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr; 1527 unsigned long int na = ntohl(addr4->sin_addr.s_addr); 1528 1529 if (IN_LOOPBACK(na) || /* 127.0.0.0/8 */ 1530 (na & 0xffff0000) == 0xa9fe0000) { /* 169.254.0.0/16 */ 1531 return IPV6_ADDR_SCOPE_LINKLOCAL; 1532 } else { 1533 /* 1534 * RFC 6724 section 3.2. Other IPv4 addresses, including private addresses 1535 * and shared addresses (100.64.0.0/10), are assigned global scope. 1536 */ 1537 return IPV6_ADDR_SCOPE_GLOBAL; 1538 } 1539 } else { 1540 /* 1541 * This should never happen. 1542 * Return a scope with low priority as a last resort. 1543 */ 1544 return IPV6_ADDR_SCOPE_NODELOCAL; 1545 } 1546 } 1547 1548 /* These macros are modelled after the ones in <netinet/in6.h>. */ 1549 1550 /* RFC 4380, section 2.6 */ 1551 #define IN6_IS_ADDR_TEREDO(a) \ 1552 ((*(const uint32_t *)(const void *)(&(a)->s6_addr[0]) == ntohl(0x20010000))) 1553 1554 /* RFC 3056, section 2. */ 1555 #define IN6_IS_ADDR_6TO4(a) \ 1556 (((a)->s6_addr[0] == 0x20) && ((a)->s6_addr[1] == 0x02)) 1557 1558 /* 6bone testing address area (3ffe::/16), deprecated in RFC 3701. */ 1559 #define IN6_IS_ADDR_6BONE(a) \ 1560 (((a)->s6_addr[0] == 0x3f) && ((a)->s6_addr[1] == 0xfe)) 1561 1562 /* 1563 * Get the label for a given IPv4/IPv6 address. 1564 * RFC 6724, section 2.1. 1565 */ 1566 1567 /*ARGSUSED*/ 1568 static int 1569 _get_label(const struct sockaddr *addr) 1570 { 1571 if (addr->sa_family == AF_INET) { 1572 return 4; 1573 } else if (addr->sa_family == AF_INET6) { 1574 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *) addr; 1575 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) { 1576 return 0; 1577 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) { 1578 return 4; 1579 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) { 1580 return 2; 1581 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) { 1582 return 5; 1583 } else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) { 1584 return 13; 1585 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr)) { 1586 return 3; 1587 } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) { 1588 return 11; 1589 } else if (IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) { 1590 return 12; 1591 } else { 1592 /* All other IPv6 addresses, including global unicast addresses. */ 1593 return 1; 1594 } 1595 } else { 1596 /* 1597 * This should never happen. 1598 * Return a semi-random label as a last resort. 1599 */ 1600 return 1; 1601 } 1602 } 1603 1604 /* 1605 * Get the precedence for a given IPv4/IPv6 address. 1606 * RFC 6724, section 2.1. 1607 */ 1608 1609 /*ARGSUSED*/ 1610 static int 1611 _get_precedence(const struct sockaddr *addr) 1612 { 1613 if (addr->sa_family == AF_INET) { 1614 return 35; 1615 } else if (addr->sa_family == AF_INET6) { 1616 const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr; 1617 if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) { 1618 return 50; 1619 } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) { 1620 return 35; 1621 } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) { 1622 return 30; 1623 } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) { 1624 return 5; 1625 } else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) { 1626 return 3; 1627 } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr) || 1628 IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr) || 1629 IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) { 1630 return 1; 1631 } else { 1632 /* All other IPv6 addresses, including global unicast addresses. */ 1633 return 40; 1634 } 1635 } else { 1636 return 1; 1637 } 1638 } 1639 1640 /* 1641 * Find number of matching initial bits between the two addresses a1 and a2. 1642 */ 1643 1644 /*ARGSUSED*/ 1645 static int 1646 _common_prefix_len(const struct in6_addr *a1, const struct in6_addr *a2) 1647 { 1648 const char *p1 = (const char *)a1; 1649 const char *p2 = (const char *)a2; 1650 unsigned i; 1651 1652 for (i = 0; i < sizeof(*a1); ++i) { 1653 int x, j; 1654 1655 if (p1[i] == p2[i]) { 1656 continue; 1657 } 1658 x = p1[i] ^ p2[i]; 1659 for (j = 0; j < CHAR_BIT; ++j) { 1660 if (x & (1 << (CHAR_BIT - 1))) { 1661 return i * CHAR_BIT + j; 1662 } 1663 x <<= 1; 1664 } 1665 } 1666 return sizeof(*a1) * CHAR_BIT; 1667 } 1668 1669 /* 1670 * Compare two source/destination address pairs. 1671 * RFC 6724, section 6. 1672 */ 1673 1674 /*ARGSUSED*/ 1675 static int 1676 _rfc6724_compare(const void *ptr1, const void* ptr2) 1677 { 1678 const struct addrinfo_sort_elem *a1 = (const struct addrinfo_sort_elem *)ptr1; 1679 const struct addrinfo_sort_elem *a2 = (const struct addrinfo_sort_elem *)ptr2; 1680 int scope_src1, scope_dst1, scope_match1; 1681 int scope_src2, scope_dst2, scope_match2; 1682 int label_src1, label_dst1, label_match1; 1683 int label_src2, label_dst2, label_match2; 1684 int precedence1, precedence2; 1685 int prefixlen1, prefixlen2; 1686 1687 /* Rule 1: Avoid unusable destinations. */ 1688 if (a1->has_src_addr != a2->has_src_addr) { 1689 return a2->has_src_addr - a1->has_src_addr; 1690 } 1691 1692 /* Rule 2: Prefer matching scope. */ 1693 scope_src1 = _get_scope(&a1->src_addr.generic); 1694 scope_dst1 = _get_scope(a1->ai->ai_addr); 1695 scope_match1 = (scope_src1 == scope_dst1); 1696 1697 scope_src2 = _get_scope(&a2->src_addr.generic); 1698 scope_dst2 = _get_scope(a2->ai->ai_addr); 1699 scope_match2 = (scope_src2 == scope_dst2); 1700 1701 if (scope_match1 != scope_match2) { 1702 return scope_match2 - scope_match1; 1703 } 1704 1705 /* 1706 * Rule 3: Avoid deprecated addresses. 1707 * TODO(sesse): We don't currently have a good way of finding this. 1708 */ 1709 1710 /* 1711 * Rule 4: Prefer home addresses. 1712 * TODO(sesse): We don't currently have a good way of finding this. 1713 */ 1714 1715 /* Rule 5: Prefer matching label. */ 1716 label_src1 = _get_label(&a1->src_addr.generic); 1717 label_dst1 = _get_label(a1->ai->ai_addr); 1718 label_match1 = (label_src1 == label_dst1); 1719 1720 label_src2 = _get_label(&a2->src_addr.generic); 1721 label_dst2 = _get_label(a2->ai->ai_addr); 1722 label_match2 = (label_src2 == label_dst2); 1723 1724 if (label_match1 != label_match2) { 1725 return label_match2 - label_match1; 1726 } 1727 1728 /* Rule 6: Prefer higher precedence. */ 1729 precedence1 = _get_precedence(a1->ai->ai_addr); 1730 precedence2 = _get_precedence(a2->ai->ai_addr); 1731 if (precedence1 != precedence2) { 1732 return precedence2 - precedence1; 1733 } 1734 1735 /* 1736 * Rule 7: Prefer native transport. 1737 * TODO(sesse): We don't currently have a good way of finding this. 1738 */ 1739 1740 /* Rule 8: Prefer smaller scope. */ 1741 if (scope_dst1 != scope_dst2) { 1742 return scope_dst1 - scope_dst2; 1743 } 1744 1745 /* 1746 * Rule 9: Use longest matching prefix. 1747 * We implement this for IPv6 only, as the rules in RFC 6724 don't seem 1748 * to work very well directly applied to IPv4. (glibc uses information from 1749 * the routing table for a custom IPv4 implementation here.) 1750 */ 1751 if (a1->has_src_addr && a1->ai->ai_addr->sa_family == AF_INET6 && 1752 a2->has_src_addr && a2->ai->ai_addr->sa_family == AF_INET6) { 1753 const struct sockaddr_in6 *a1_src = &a1->src_addr.in6; 1754 const struct sockaddr_in6 *a1_dst = (const struct sockaddr_in6 *)a1->ai->ai_addr; 1755 const struct sockaddr_in6 *a2_src = &a2->src_addr.in6; 1756 const struct sockaddr_in6 *a2_dst = (const struct sockaddr_in6 *)a2->ai->ai_addr; 1757 prefixlen1 = _common_prefix_len(&a1_src->sin6_addr, &a1_dst->sin6_addr); 1758 prefixlen2 = _common_prefix_len(&a2_src->sin6_addr, &a2_dst->sin6_addr); 1759 if (prefixlen1 != prefixlen2) { 1760 return prefixlen2 - prefixlen1; 1761 } 1762 } 1763 1764 /* 1765 * Rule 10: Leave the order unchanged. 1766 * We need this since qsort() is not necessarily stable. 1767 */ 1768 return a1->original_order - a2->original_order; 1769 } 1770 1771 /* 1772 * Find the source address that will be used if trying to connect to the given 1773 * address. src_addr must be large enough to hold a struct sockaddr_in6. 1774 * 1775 * Returns 1 if a source address was found, 0 if the address is unreachable, 1776 * and -1 if a fatal error occurred. If 0 or -1, the contents of src_addr are 1777 * undefined. 1778 */ 1779 1780 /*ARGSUSED*/ 1781 static int 1782 _find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr, unsigned mark, uid_t uid) 1783 { 1784 int sock; 1785 int ret; 1786 socklen_t len; 1787 1788 switch (addr->sa_family) { 1789 case AF_INET: 1790 len = sizeof(struct sockaddr_in); 1791 break; 1792 case AF_INET6: 1793 len = sizeof(struct sockaddr_in6); 1794 break; 1795 default: 1796 /* No known usable source address for non-INET families. */ 1797 return 0; 1798 } 1799 1800 sock = socket(addr->sa_family, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP); 1801 if (sock == -1) { 1802 if (errno == EAFNOSUPPORT) { 1803 return 0; 1804 } else { 1805 return -1; 1806 } 1807 } 1808 if (mark != MARK_UNSET && setsockopt(sock, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)) < 0) { 1809 close(sock); 1810 return 0; 1811 } 1812 if (uid > 0 && uid != NET_CONTEXT_INVALID_UID && fchown(sock, uid, (gid_t)-1) < 0) { 1813 close(sock); 1814 return 0; 1815 } 1816 do { 1817 ret = __connect(sock, addr, len); 1818 } while (ret == -1 && errno == EINTR); 1819 1820 if (ret == -1) { 1821 close(sock); 1822 return 0; 1823 } 1824 1825 if (src_addr && getsockname(sock, src_addr, &len) == -1) { 1826 close(sock); 1827 return -1; 1828 } 1829 close(sock); 1830 return 1; 1831 } 1832 1833 /* 1834 * Sort the linked list starting at sentinel->ai_next in RFC6724 order. 1835 * Will leave the list unchanged if an error occurs. 1836 */ 1837 1838 /*ARGSUSED*/ 1839 static void 1840 _rfc6724_sort(struct addrinfo *list_sentinel, unsigned mark, uid_t uid) 1841 { 1842 struct addrinfo *cur; 1843 int nelem = 0, i; 1844 struct addrinfo_sort_elem *elems; 1845 1846 cur = list_sentinel->ai_next; 1847 while (cur) { 1848 ++nelem; 1849 cur = cur->ai_next; 1850 } 1851 1852 elems = (struct addrinfo_sort_elem *)malloc(nelem * sizeof(struct addrinfo_sort_elem)); 1853 if (elems == NULL) { 1854 goto error; 1855 } 1856 1857 /* 1858 * Convert the linked list to an array that also contains the candidate 1859 * source address for each destination address. 1860 */ 1861 for (i = 0, cur = list_sentinel->ai_next; i < nelem; ++i, cur = cur->ai_next) { 1862 int has_src_addr; 1863 assert(cur != NULL); 1864 elems[i].ai = cur; 1865 elems[i].original_order = i; 1866 1867 has_src_addr = _find_src_addr(cur->ai_addr, &elems[i].src_addr.generic, mark, uid); 1868 if (has_src_addr == -1) { 1869 goto error; 1870 } 1871 elems[i].has_src_addr = has_src_addr; 1872 } 1873 1874 /* Sort the addresses, and rearrange the linked list so it matches the sorted order. */ 1875 qsort((void *)elems, nelem, sizeof(struct addrinfo_sort_elem), _rfc6724_compare); 1876 1877 list_sentinel->ai_next = elems[0].ai; 1878 for (i = 0; i < nelem - 1; ++i) { 1879 elems[i].ai->ai_next = elems[i + 1].ai; 1880 } 1881 elems[nelem - 1].ai->ai_next = NULL; 1882 1883 error: 1884 free(elems); 1885 } 1886 1887 /*ARGSUSED*/ 1888 static int 1889 _dns_getaddrinfo(void *rv, void *cb_data, va_list ap) 1890 { 1891 struct addrinfo *ai; 1892 querybuf *buf, *buf2; 1893 const char *name; 1894 const struct addrinfo *pai; 1895 struct addrinfo sentinel, *cur; 1896 struct res_target q, q2; 1897 res_state res; 1898 const struct android_net_context *netcontext; 1899 1900 name = va_arg(ap, char *); 1901 pai = va_arg(ap, const struct addrinfo *); 1902 netcontext = va_arg(ap, const struct android_net_context *); 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 query_ipv6 = _have_ipv6(netcontext->app_mark, netcontext->uid); 1932 query_ipv4 = _have_ipv4(netcontext->app_mark, netcontext->uid); 1933 } 1934 if (query_ipv6) { 1935 q.qtype = T_AAAA; 1936 if (query_ipv4) { 1937 q.next = &q2; 1938 q2.name = name; 1939 q2.qclass = C_IN; 1940 q2.qtype = T_A; 1941 q2.answer = buf2->buf; 1942 q2.anslen = sizeof(buf2->buf); 1943 } 1944 } else if (query_ipv4) { 1945 q.qtype = T_A; 1946 } else { 1947 free(buf); 1948 free(buf2); 1949 return NS_NOTFOUND; 1950 } 1951 break; 1952 case AF_INET: 1953 q.name = name; 1954 q.qclass = C_IN; 1955 q.qtype = T_A; 1956 q.answer = buf->buf; 1957 q.anslen = sizeof(buf->buf); 1958 break; 1959 case AF_INET6: 1960 q.name = name; 1961 q.qclass = C_IN; 1962 q.qtype = T_AAAA; 1963 q.answer = buf->buf; 1964 q.anslen = sizeof(buf->buf); 1965 break; 1966 default: 1967 free(buf); 1968 free(buf2); 1969 return NS_UNAVAIL; 1970 } 1971 1972 res = __res_get_state(); 1973 if (res == NULL) { 1974 free(buf); 1975 free(buf2); 1976 return NS_NOTFOUND; 1977 } 1978 1979 /* this just sets our netid val in the thread private data so we don't have to 1980 * modify the api's all the way down to res_send.c's res_nsend. We could 1981 * fully populate the thread private data here, but if we get down there 1982 * and have a cache hit that would be wasted, so we do the rest there on miss 1983 */ 1984 res_setnetid(res, netcontext->dns_netid); 1985 res_setmark(res, netcontext->dns_mark); 1986 if (res_searchN(name, &q, res) < 0) { 1987 __res_put_state(res); 1988 free(buf); 1989 free(buf2); 1990 return NS_NOTFOUND; 1991 } 1992 ai = getanswer(buf, q.n, q.name, q.qtype, pai); 1993 if (ai) { 1994 cur->ai_next = ai; 1995 while (cur && cur->ai_next) 1996 cur = cur->ai_next; 1997 } 1998 if (q.next) { 1999 ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai); 2000 if (ai) 2001 cur->ai_next = ai; 2002 } 2003 free(buf); 2004 free(buf2); 2005 if (sentinel.ai_next == NULL) { 2006 __res_put_state(res); 2007 switch (h_errno) { 2008 case HOST_NOT_FOUND: 2009 return NS_NOTFOUND; 2010 case TRY_AGAIN: 2011 return NS_TRYAGAIN; 2012 default: 2013 return NS_UNAVAIL; 2014 } 2015 } 2016 2017 _rfc6724_sort(&sentinel, netcontext->app_mark, netcontext->uid); 2018 2019 __res_put_state(res); 2020 2021 *((struct addrinfo **)rv) = sentinel.ai_next; 2022 return NS_SUCCESS; 2023 } 2024 2025 static void 2026 _sethtent(FILE **hostf) 2027 { 2028 2029 if (!*hostf) 2030 *hostf = fopen(_PATH_HOSTS, "re"); 2031 else 2032 rewind(*hostf); 2033 } 2034 2035 static void 2036 _endhtent(FILE **hostf) 2037 { 2038 2039 if (*hostf) { 2040 (void) fclose(*hostf); 2041 *hostf = NULL; 2042 } 2043 } 2044 2045 static struct addrinfo * 2046 _gethtent(FILE **hostf, const char *name, const struct addrinfo *pai) 2047 { 2048 char *p; 2049 char *cp, *tname, *cname; 2050 struct addrinfo hints, *res0, *res; 2051 int error; 2052 const char *addr; 2053 char hostbuf[8*1024]; 2054 2055 // fprintf(stderr, "_gethtent() name = '%s'\n", name); 2056 assert(name != NULL); 2057 assert(pai != NULL); 2058 2059 if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "re"))) 2060 return (NULL); 2061 again: 2062 if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf))) 2063 return (NULL); 2064 if (*p == '#') 2065 goto again; 2066 if (!(cp = strpbrk(p, "#\n"))) 2067 goto again; 2068 *cp = '\0'; 2069 if (!(cp = strpbrk(p, " \t"))) 2070 goto again; 2071 *cp++ = '\0'; 2072 addr = p; 2073 /* if this is not something we're looking for, skip it. */ 2074 cname = NULL; 2075 while (cp && *cp) { 2076 if (*cp == ' ' || *cp == '\t') { 2077 cp++; 2078 continue; 2079 } 2080 if (!cname) 2081 cname = cp; 2082 tname = cp; 2083 if ((cp = strpbrk(cp, " \t")) != NULL) 2084 *cp++ = '\0'; 2085 // fprintf(stderr, "\ttname = '%s'", tname); 2086 if (strcasecmp(name, tname) == 0) 2087 goto found; 2088 } 2089 goto again; 2090 2091 found: 2092 hints = *pai; 2093 hints.ai_flags = AI_NUMERICHOST; 2094 error = getaddrinfo(addr, NULL, &hints, &res0); 2095 if (error) 2096 goto again; 2097 for (res = res0; res; res = res->ai_next) { 2098 /* cover it up */ 2099 res->ai_flags = pai->ai_flags; 2100 2101 if (pai->ai_flags & AI_CANONNAME) { 2102 if (get_canonname(pai, res, cname) != 0) { 2103 freeaddrinfo(res0); 2104 goto again; 2105 } 2106 } 2107 } 2108 return res0; 2109 } 2110 2111 /*ARGSUSED*/ 2112 static int 2113 _files_getaddrinfo(void *rv, void *cb_data, va_list ap) 2114 { 2115 const char *name; 2116 const struct addrinfo *pai; 2117 struct addrinfo sentinel, *cur; 2118 struct addrinfo *p; 2119 FILE *hostf = NULL; 2120 2121 name = va_arg(ap, char *); 2122 pai = va_arg(ap, struct addrinfo *); 2123 2124 // fprintf(stderr, "_files_getaddrinfo() name = '%s'\n", name); 2125 memset(&sentinel, 0, sizeof(sentinel)); 2126 cur = &sentinel; 2127 2128 _sethtent(&hostf); 2129 while ((p = _gethtent(&hostf, name, pai)) != NULL) { 2130 cur->ai_next = p; 2131 while (cur && cur->ai_next) 2132 cur = cur->ai_next; 2133 } 2134 _endhtent(&hostf); 2135 2136 *((struct addrinfo **)rv) = sentinel.ai_next; 2137 if (sentinel.ai_next == NULL) 2138 return NS_NOTFOUND; 2139 return NS_SUCCESS; 2140 } 2141 2142 /* resolver logic */ 2143 2144 /* 2145 * Formulate a normal query, send, and await answer. 2146 * Returned answer is placed in supplied buffer "answer". 2147 * Perform preliminary check of answer, returning success only 2148 * if no error is indicated and the answer count is nonzero. 2149 * Return the size of the response on success, -1 on error. 2150 * Error number is left in h_errno. 2151 * 2152 * Caller must parse answer and determine whether it answers the question. 2153 */ 2154 static int 2155 res_queryN(const char *name, /* domain name */ struct res_target *target, 2156 res_state res) 2157 { 2158 u_char buf[MAXPACKET]; 2159 HEADER *hp; 2160 int n; 2161 struct res_target *t; 2162 int rcode; 2163 int ancount; 2164 2165 assert(name != NULL); 2166 /* XXX: target may be NULL??? */ 2167 2168 rcode = NOERROR; 2169 ancount = 0; 2170 2171 for (t = target; t; t = t->next) { 2172 int class, type; 2173 u_char *answer; 2174 int anslen; 2175 2176 hp = (HEADER *)(void *)t->answer; 2177 hp->rcode = NOERROR; /* default */ 2178 2179 /* make it easier... */ 2180 class = t->qclass; 2181 type = t->qtype; 2182 answer = t->answer; 2183 anslen = t->anslen; 2184 #ifdef DEBUG 2185 if (res->options & RES_DEBUG) 2186 printf(";; res_nquery(%s, %d, %d)\n", name, class, type); 2187 #endif 2188 2189 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL, 2190 buf, sizeof(buf)); 2191 #ifdef RES_USE_EDNS0 2192 if (n > 0 && (res->options & RES_USE_EDNS0) != 0) 2193 n = res_nopt(res, n, buf, sizeof(buf), anslen); 2194 #endif 2195 if (n <= 0) { 2196 #ifdef DEBUG 2197 if (res->options & RES_DEBUG) 2198 printf(";; res_nquery: mkquery failed\n"); 2199 #endif 2200 h_errno = NO_RECOVERY; 2201 return n; 2202 } 2203 n = res_nsend(res, buf, n, answer, anslen); 2204 #if 0 2205 if (n < 0) { 2206 #ifdef DEBUG 2207 if (res->options & RES_DEBUG) 2208 printf(";; res_query: send error\n"); 2209 #endif 2210 h_errno = TRY_AGAIN; 2211 return n; 2212 } 2213 #endif 2214 2215 if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) { 2216 rcode = hp->rcode; /* record most recent error */ 2217 #ifdef DEBUG 2218 if (res->options & RES_DEBUG) 2219 printf(";; rcode = %u, ancount=%u\n", hp->rcode, 2220 ntohs(hp->ancount)); 2221 #endif 2222 continue; 2223 } 2224 2225 ancount += ntohs(hp->ancount); 2226 2227 t->n = n; 2228 } 2229 2230 if (ancount == 0) { 2231 switch (rcode) { 2232 case NXDOMAIN: 2233 h_errno = HOST_NOT_FOUND; 2234 break; 2235 case SERVFAIL: 2236 h_errno = TRY_AGAIN; 2237 break; 2238 case NOERROR: 2239 h_errno = NO_DATA; 2240 break; 2241 case FORMERR: 2242 case NOTIMP: 2243 case REFUSED: 2244 default: 2245 h_errno = NO_RECOVERY; 2246 break; 2247 } 2248 return -1; 2249 } 2250 return ancount; 2251 } 2252 2253 /* 2254 * Formulate a normal query, send, and retrieve answer in supplied buffer. 2255 * Return the size of the response on success, -1 on error. 2256 * If enabled, implement search rules until answer or unrecoverable failure 2257 * is detected. Error code, if any, is left in h_errno. 2258 */ 2259 static int 2260 res_searchN(const char *name, struct res_target *target, res_state res) 2261 { 2262 const char *cp, * const *domain; 2263 HEADER *hp; 2264 u_int dots; 2265 int trailing_dot, ret, saved_herrno; 2266 int got_nodata = 0, got_servfail = 0, tried_as_is = 0; 2267 2268 assert(name != NULL); 2269 assert(target != NULL); 2270 2271 hp = (HEADER *)(void *)target->answer; /*XXX*/ 2272 2273 errno = 0; 2274 h_errno = HOST_NOT_FOUND; /* default, if we never query */ 2275 dots = 0; 2276 for (cp = name; *cp; cp++) 2277 dots += (*cp == '.'); 2278 trailing_dot = 0; 2279 if (cp > name && *--cp == '.') 2280 trailing_dot++; 2281 2282 2283 //fprintf(stderr, "res_searchN() name = '%s'\n", name); 2284 2285 /* 2286 * if there aren't any dots, it could be a user-level alias 2287 */ 2288 if (!dots && (cp = __hostalias(name)) != NULL) { 2289 ret = res_queryN(cp, target, res); 2290 return ret; 2291 } 2292 2293 /* 2294 * If there are dots in the name already, let's just give it a try 2295 * 'as is'. The threshold can be set with the "ndots" option. 2296 */ 2297 saved_herrno = -1; 2298 if (dots >= res->ndots) { 2299 ret = res_querydomainN(name, NULL, target, res); 2300 if (ret > 0) 2301 return (ret); 2302 saved_herrno = h_errno; 2303 tried_as_is++; 2304 } 2305 2306 /* 2307 * We do at least one level of search if 2308 * - there is no dot and RES_DEFNAME is set, or 2309 * - there is at least one dot, there is no trailing dot, 2310 * and RES_DNSRCH is set. 2311 */ 2312 if ((!dots && (res->options & RES_DEFNAMES)) || 2313 (dots && !trailing_dot && (res->options & RES_DNSRCH))) { 2314 int done = 0; 2315 2316 /* Unfortunately we need to set stuff up before 2317 * the domain stuff is tried. Will have a better 2318 * fix after thread pools are used. 2319 */ 2320 _resolv_populate_res_for_net(res); 2321 2322 for (domain = (const char * const *)res->dnsrch; 2323 *domain && !done; 2324 domain++) { 2325 2326 ret = res_querydomainN(name, *domain, target, res); 2327 if (ret > 0) 2328 return ret; 2329 2330 /* 2331 * If no server present, give up. 2332 * If name isn't found in this domain, 2333 * keep trying higher domains in the search list 2334 * (if that's enabled). 2335 * On a NO_DATA error, keep trying, otherwise 2336 * a wildcard entry of another type could keep us 2337 * from finding this entry higher in the domain. 2338 * If we get some other error (negative answer or 2339 * server failure), then stop searching up, 2340 * but try the input name below in case it's 2341 * fully-qualified. 2342 */ 2343 if (errno == ECONNREFUSED) { 2344 h_errno = TRY_AGAIN; 2345 return -1; 2346 } 2347 2348 switch (h_errno) { 2349 case NO_DATA: 2350 got_nodata++; 2351 /* FALLTHROUGH */ 2352 case HOST_NOT_FOUND: 2353 /* keep trying */ 2354 break; 2355 case TRY_AGAIN: 2356 if (hp->rcode == SERVFAIL) { 2357 /* try next search element, if any */ 2358 got_servfail++; 2359 break; 2360 } 2361 /* FALLTHROUGH */ 2362 default: 2363 /* anything else implies that we're done */ 2364 done++; 2365 } 2366 /* 2367 * if we got here for some reason other than DNSRCH, 2368 * we only wanted one iteration of the loop, so stop. 2369 */ 2370 if (!(res->options & RES_DNSRCH)) 2371 done++; 2372 } 2373 } 2374 2375 /* 2376 * if we have not already tried the name "as is", do that now. 2377 * note that we do this regardless of how many dots were in the 2378 * name or whether it ends with a dot. 2379 */ 2380 if (!tried_as_is) { 2381 ret = res_querydomainN(name, NULL, target, res); 2382 if (ret > 0) 2383 return ret; 2384 } 2385 2386 /* 2387 * if we got here, we didn't satisfy the search. 2388 * if we did an initial full query, return that query's h_errno 2389 * (note that we wouldn't be here if that query had succeeded). 2390 * else if we ever got a nodata, send that back as the reason. 2391 * else send back meaningless h_errno, that being the one from 2392 * the last DNSRCH we did. 2393 */ 2394 if (saved_herrno != -1) 2395 h_errno = saved_herrno; 2396 else if (got_nodata) 2397 h_errno = NO_DATA; 2398 else if (got_servfail) 2399 h_errno = TRY_AGAIN; 2400 return -1; 2401 } 2402 2403 /* 2404 * Perform a call on res_query on the concatenation of name and domain, 2405 * removing a trailing dot from name if domain is NULL. 2406 */ 2407 static int 2408 res_querydomainN(const char *name, const char *domain, 2409 struct res_target *target, res_state res) 2410 { 2411 char nbuf[MAXDNAME]; 2412 const char *longname = nbuf; 2413 size_t n, d; 2414 2415 assert(name != NULL); 2416 /* XXX: target may be NULL??? */ 2417 2418 #ifdef DEBUG 2419 if (res->options & RES_DEBUG) 2420 printf(";; res_querydomain(%s, %s)\n", 2421 name, domain?domain:"<Nil>"); 2422 #endif 2423 if (domain == NULL) { 2424 /* 2425 * Check for trailing '.'; 2426 * copy without '.' if present. 2427 */ 2428 n = strlen(name); 2429 if (n + 1 > sizeof(nbuf)) { 2430 h_errno = NO_RECOVERY; 2431 return -1; 2432 } 2433 if (n > 0 && name[--n] == '.') { 2434 strncpy(nbuf, name, n); 2435 nbuf[n] = '\0'; 2436 } else 2437 longname = name; 2438 } else { 2439 n = strlen(name); 2440 d = strlen(domain); 2441 if (n + 1 + d + 1 > sizeof(nbuf)) { 2442 h_errno = NO_RECOVERY; 2443 return -1; 2444 } 2445 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain); 2446 } 2447 return res_queryN(longname, target, res); 2448 } 2449
