1 /* $KAME: getaddrinfo.c,v 1.15 2000/07/09 04:37:24 itojun Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-3-Clause 5 * 6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the project nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 /* 35 * Issues to be discussed: 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 * - freeaddrinfo(NULL). RFC2553 is silent about it. XNET 5.2 says it is 40 * invalid. Current code accepts NULL to be compatible with other OSes. 41 * 42 * Note: 43 * - The code filters out AFs that are not supported by the kernel, 44 * when globbing NULL hostname (to loopback, or wildcard). Is it the right 45 * thing to do? What is the relationship with post-RFC2553 AI_ADDRCONFIG 46 * in ai_flags? 47 * - (post-2553) semantics of AI_ADDRCONFIG itself is too vague. 48 * (1) what should we do against numeric hostname (2) what should we do 49 * against NULL hostname (3) what is AI_ADDRCONFIG itself. AF not ready? 50 * non-loopback address configured? global address configured? 51 * 52 * OS specific notes for freebsd4: 53 * - FreeBSD supported $GAI. The code does not. 54 */ 55 56 #include "namespace.h" 57 #include <sys/param.h> 58 #include <sys/socket.h> 59 #include <net/if.h> 60 #include <netinet/in.h> 61 #include <net/if_types.h> 62 #include <ifaddrs.h> 63 #include <sys/queue.h> 64 #ifdef INET6 65 #include <sys/sysctl.h> 66 #include <sys/ioctl.h> 67 #include <netinet6/in6_var.h> 68 #include <netinet6/nd6.h> 69 #endif 70 #include <arpa/inet.h> 71 #include <arpa/nameser.h> 72 #include <rpc/rpc.h> 73 #include <rpcsvc/yp_prot.h> 74 #include <rpcsvc/ypclnt.h> 75 #include <netdb.h> 76 #include <resolv.h> 77 #include <string.h> 78 #include <stdlib.h> 79 #include <stddef.h> 80 #include <ctype.h> 81 #include <unistd.h> 82 #include <stdio.h> 83 #include <errno.h> 84 85 #include "res_config.h" 86 87 #ifdef DEBUG 88 #include <syslog.h> 89 #endif 90 91 #include <stdarg.h> 92 #include <nsswitch.h> 93 #include "un-namespace.h" 94 #include "netdb_private.h" 95 #include "libc_private.h" 96 #ifdef NS_CACHING 97 #include "nscache.h" 98 #endif 99 100 #define ANY 0 101 #define YES 1 102 #define NO 0 103 104 static const char in_addrany[] = { 0, 0, 0, 0 }; 105 static const char in_loopback[] = { 127, 0, 0, 1 }; 106 #ifdef INET6 107 static const char in6_addrany[] = { 108 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 109 }; 110 static const char in6_loopback[] = { 111 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 112 }; 113 #endif 114 115 struct policyqueue { 116 TAILQ_ENTRY(policyqueue) pc_entry; 117 #ifdef INET6 118 struct in6_addrpolicy pc_policy; 119 #endif 120 }; 121 TAILQ_HEAD(policyhead, policyqueue); 122 123 static const struct afd { 124 int a_af; 125 int a_addrlen; 126 socklen_t a_socklen; 127 int a_off; 128 const char *a_addrany; 129 const char *a_loopback; 130 int a_scoped; 131 } afdl [] = { 132 #ifdef INET6 133 #define N_INET6 0 134 {PF_INET6, sizeof(struct in6_addr), 135 sizeof(struct sockaddr_in6), 136 offsetof(struct sockaddr_in6, sin6_addr), 137 in6_addrany, in6_loopback, 1}, 138 #define N_INET 1 139 #define N_LOCAL 2 140 #else 141 #define N_INET 0 142 #define N_LOCAL 1 143 #endif 144 {PF_INET, sizeof(struct in_addr), 145 sizeof(struct sockaddr_in), 146 offsetof(struct sockaddr_in, sin_addr), 147 in_addrany, in_loopback, 0}, 148 #define sizeofmember(type, member) (sizeof(((type *)0)->member)) 149 {PF_LOCAL, sizeofmember(struct sockaddr_un, sun_path), 150 sizeof(struct sockaddr_un), 151 offsetof(struct sockaddr_un, sun_path), 152 NULL, NULL, 0}, 153 {0, 0, 0, 0, NULL, NULL, 0}, 154 }; 155 156 struct explore { 157 int e_af; 158 int e_socktype; 159 int e_protocol; 160 int e_wild; 161 #define AF_ANY 0x01 162 #define SOCKTYPE_ANY 0x02 163 #define PROTOCOL_ANY 0x04 164 #define WILD_AF(ex) ((ex)->e_wild & AF_ANY) 165 #define WILD_SOCKTYPE(ex) ((ex)->e_wild & SOCKTYPE_ANY) 166 #define WILD_PROTOCOL(ex) ((ex)->e_wild & PROTOCOL_ANY) 167 }; 168 169 static const struct explore explore[] = { 170 #ifdef INET6 171 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP, 172 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY }, 173 { PF_INET6, SOCK_STREAM, IPPROTO_TCP, 174 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY }, 175 { PF_INET6, SOCK_STREAM, IPPROTO_SCTP, 176 AF_ANY | SOCKTYPE_ANY }, 177 { PF_INET6, SOCK_SEQPACKET, IPPROTO_SCTP, 178 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY }, 179 { PF_INET6, SOCK_DGRAM, IPPROTO_UDPLITE, 180 AF_ANY | SOCKTYPE_ANY }, 181 { PF_INET6, SOCK_RAW, ANY, 182 AF_ANY | PROTOCOL_ANY }, 183 #endif 184 { PF_INET, SOCK_DGRAM, IPPROTO_UDP, 185 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY }, 186 { PF_INET, SOCK_STREAM, IPPROTO_TCP, 187 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY }, 188 { PF_INET, SOCK_STREAM, IPPROTO_SCTP, 189 AF_ANY | SOCKTYPE_ANY }, 190 { PF_INET, SOCK_SEQPACKET, IPPROTO_SCTP, 191 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY }, 192 { PF_INET, SOCK_DGRAM, IPPROTO_UDPLITE, 193 AF_ANY | SOCKTYPE_ANY }, 194 { PF_INET, SOCK_RAW, ANY, 195 AF_ANY | PROTOCOL_ANY }, 196 { PF_LOCAL, SOCK_DGRAM, ANY, 197 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY }, 198 { PF_LOCAL, SOCK_STREAM, ANY, 199 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY }, 200 { PF_LOCAL, SOCK_SEQPACKET, ANY, 201 AF_ANY | SOCKTYPE_ANY | PROTOCOL_ANY }, 202 { -1, 0, 0, 0 }, 203 }; 204 205 #ifdef INET6 206 #define PTON_MAX 16 207 #else 208 #define PTON_MAX 4 209 #endif 210 211 #define AIO_SRCFLAG_DEPRECATED 0x1 212 213 struct ai_order { 214 union { 215 struct sockaddr_storage aiou_ss; 216 struct sockaddr aiou_sa; 217 } aio_src_un; 218 #define aio_srcsa aio_src_un.aiou_sa 219 u_int32_t aio_srcflag; 220 int aio_srcscope; 221 int aio_dstscope; 222 struct policyqueue *aio_srcpolicy; 223 struct policyqueue *aio_dstpolicy; 224 struct addrinfo *aio_ai; 225 int aio_matchlen; 226 int aio_initial_sequence; 227 }; 228 229 static const ns_src default_dns_files[] = { 230 { NSSRC_FILES, NS_SUCCESS }, 231 { NSSRC_DNS, NS_SUCCESS }, 232 { 0 } 233 }; 234 235 struct res_target { 236 struct res_target *next; 237 const char *name; /* domain name */ 238 int qclass, qtype; /* class and type of query */ 239 u_char *answer; /* buffer to put answer */ 240 int anslen; /* size of answer buffer */ 241 int n; /* result length */ 242 }; 243 244 #define MAXPACKET (64*1024) 245 246 typedef union { 247 HEADER hdr; 248 u_char buf[MAXPACKET]; 249 } querybuf; 250 251 static int str2number(const char *, int *); 252 static int explore_copy(const struct addrinfo *, const struct addrinfo *, 253 struct addrinfo **); 254 static int explore_null(const struct addrinfo *, 255 const char *, struct addrinfo **); 256 static int explore_numeric(const struct addrinfo *, const char *, 257 const char *, struct addrinfo **, const char *); 258 static int explore_numeric_scope(const struct addrinfo *, const char *, 259 const char *, struct addrinfo **); 260 static int get_canonname(const struct addrinfo *, 261 struct addrinfo *, const char *); 262 static struct addrinfo *get_ai(const struct addrinfo *, 263 const struct afd *, const char *); 264 static struct addrinfo *copy_ai(const struct addrinfo *); 265 static int get_portmatch(const struct addrinfo *, const char *); 266 static int get_port(struct addrinfo *, const char *, int); 267 static const struct afd *find_afd(int); 268 static int addrconfig(struct addrinfo *); 269 #ifdef INET6 270 static int is_ifdisabled(char *); 271 #endif 272 static void set_source(struct ai_order *, struct policyhead *); 273 static int comp_dst(const void *, const void *); 274 #ifdef INET6 275 static int ip6_str2scopeid(const char *, struct sockaddr_in6 *, u_int32_t *); 276 #endif 277 static int gai_addr2scopetype(struct sockaddr *); 278 279 static int explore_fqdn(const struct addrinfo *, const char *, 280 const char *, struct addrinfo **); 281 282 static int reorder(struct addrinfo *); 283 static int get_addrselectpolicy(struct policyhead *); 284 static void free_addrselectpolicy(struct policyhead *); 285 static struct policyqueue *match_addrselectpolicy(struct sockaddr *, 286 struct policyhead *); 287 static int matchlen(struct sockaddr *, struct sockaddr *); 288 289 static struct addrinfo *getanswer(const querybuf *, int, const char *, int, 290 const struct addrinfo *, res_state); 291 #if defined(RESOLVSORT) 292 static int addr4sort(struct addrinfo *, res_state); 293 #endif 294 static int _dns_getaddrinfo(void *, void *, va_list); 295 static void _sethtent(FILE **); 296 static void _endhtent(FILE **); 297 static struct addrinfo *_gethtent(FILE **, const char *, 298 const struct addrinfo *); 299 static int _files_getaddrinfo(void *, void *, va_list); 300 #ifdef YP 301 static struct addrinfo *_yphostent(char *, const struct addrinfo *); 302 static int _yp_getaddrinfo(void *, void *, va_list); 303 #endif 304 #ifdef NS_CACHING 305 static int addrinfo_id_func(char *, size_t *, va_list, void *); 306 static int addrinfo_marshal_func(char *, size_t *, void *, va_list, void *); 307 static int addrinfo_unmarshal_func(char *, size_t, void *, va_list, void *); 308 #endif 309 310 static int res_queryN(const char *, struct res_target *, res_state); 311 static int res_searchN(const char *, struct res_target *, res_state); 312 static int res_querydomainN(const char *, const char *, 313 struct res_target *, res_state); 314 315 /* XXX macros that make external reference is BAD. */ 316 317 #define GET_AI(ai, afd, addr) \ 318 do { \ 319 /* external reference: pai, error, and label free */ \ 320 (ai) = get_ai(pai, (afd), (addr)); \ 321 if ((ai) == NULL) { \ 322 error = EAI_MEMORY; \ 323 goto free; \ 324 } \ 325 } while (/*CONSTCOND*/0) 326 327 #define GET_PORT(ai, serv) \ 328 do { \ 329 /* external reference: error and label free */ \ 330 error = get_port((ai), (serv), 0); \ 331 if (error != 0) \ 332 goto free; \ 333 } while (/*CONSTCOND*/0) 334 335 #define GET_CANONNAME(ai, str) \ 336 do { \ 337 /* external reference: pai, error and label free */ \ 338 error = get_canonname(pai, (ai), (str)); \ 339 if (error != 0) \ 340 goto free; \ 341 } while (/*CONSTCOND*/0) 342 343 #define ERR(err) \ 344 do { \ 345 /* external reference: error, and label bad */ \ 346 error = (err); \ 347 goto bad; \ 348 /*NOTREACHED*/ \ 349 } while (/*CONSTCOND*/0) 350 351 #define MATCH_FAMILY(x, y, w) \ 352 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || (y) == PF_UNSPEC))) 353 #define MATCH(x, y, w) \ 354 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY))) 355 356 void 357 freeaddrinfo(struct addrinfo *ai) 358 { 359 struct addrinfo *next; 360 361 while (ai != NULL) { 362 next = ai->ai_next; 363 free(ai->ai_canonname); 364 /* no need to free(ai->ai_addr) */ 365 free(ai); 366 ai = next; 367 } 368 } 369 370 static int 371 str2number(const char *p, int *portp) 372 { 373 char *ep; 374 unsigned long v; 375 376 if (*p == '\0') 377 return -1; 378 ep = NULL; 379 errno = 0; 380 v = strtoul(p, &ep, 10); 381 if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX) { 382 *portp = v; 383 return 0; 384 } else 385 return -1; 386 } 387 388 int 389 getaddrinfo(const char *hostname, const char *servname, 390 const struct addrinfo *hints, struct addrinfo **res) 391 { 392 struct addrinfo sentinel; 393 struct addrinfo *cur; 394 int error = 0; 395 struct addrinfo ai, ai0, *afai; 396 struct addrinfo *pai; 397 const struct afd *afd; 398 const struct explore *ex; 399 struct addrinfo *afailist[nitems(afdl)]; 400 struct addrinfo *afai_unspec; 401 int found; 402 int numeric = 0; 403 404 /* ensure we return NULL on errors */ 405 *res = NULL; 406 407 memset(&ai, 0, sizeof(ai)); 408 409 memset(afailist, 0, sizeof(afailist)); 410 afai_unspec = NULL; 411 412 memset(&sentinel, 0, sizeof(sentinel)); 413 cur = &sentinel; 414 pai = &ai; 415 pai->ai_flags = 0; 416 pai->ai_family = PF_UNSPEC; 417 pai->ai_socktype = ANY; 418 pai->ai_protocol = ANY; 419 pai->ai_addrlen = 0; 420 pai->ai_canonname = NULL; 421 pai->ai_addr = NULL; 422 pai->ai_next = NULL; 423 424 if (hostname == NULL && servname == NULL) 425 return EAI_NONAME; 426 if (hints) { 427 /* error check for hints */ 428 if (hints->ai_addrlen || hints->ai_canonname || 429 hints->ai_addr || hints->ai_next) 430 ERR(EAI_BADHINTS); /* xxx */ 431 if (hints->ai_flags & ~AI_MASK) 432 ERR(EAI_BADFLAGS); 433 switch (hints->ai_family) { 434 case PF_UNSPEC: 435 case PF_LOCAL: 436 case PF_INET: 437 #ifdef INET6 438 case PF_INET6: 439 #endif 440 break; 441 default: 442 ERR(EAI_FAMILY); 443 } 444 memcpy(pai, hints, sizeof(*pai)); 445 446 /* 447 * if both socktype/protocol are specified, check if they 448 * are meaningful combination. 449 */ 450 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) { 451 for (ex = explore; ex->e_af >= 0; ex++) { 452 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, 453 WILD_AF(ex))) 454 continue; 455 if (!MATCH(pai->ai_socktype, ex->e_socktype, 456 WILD_SOCKTYPE(ex))) 457 continue; 458 if (!MATCH(pai->ai_protocol, ex->e_protocol, 459 WILD_PROTOCOL(ex))) 460 continue; 461 462 /* matched */ 463 break; 464 } 465 466 if (ex->e_af < 0) 467 ERR(EAI_BADHINTS); 468 } 469 } 470 471 /* 472 * RFC 3493: AI_ALL and AI_V4MAPPED are effective only against 473 * AF_INET6 query. They need to be ignored if specified in other 474 * occasions. 475 */ 476 switch (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) { 477 case AI_V4MAPPED: 478 case AI_ALL | AI_V4MAPPED: 479 #ifdef INET6 480 if (pai->ai_family != AF_INET6) 481 pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED); 482 break; 483 #endif 484 case AI_ALL: 485 pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED); 486 break; 487 } 488 489 /* 490 * check for special cases. (1) numeric servname is disallowed if 491 * socktype/protocol are left unspecified. (2) servname is disallowed 492 * for raw and other inet{,6} sockets. 493 */ 494 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1) 495 #ifdef PF_INET6 496 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1) 497 #endif 498 ) { 499 ai0 = *pai; /* backup *pai */ 500 501 if (pai->ai_family == PF_UNSPEC) { 502 #ifdef PF_INET6 503 pai->ai_family = PF_INET6; 504 #else 505 pai->ai_family = PF_INET; 506 #endif 507 } 508 error = get_portmatch(pai, servname); 509 if (error) 510 goto bad; 511 512 *pai = ai0; 513 } 514 515 ai0 = *pai; 516 517 /* 518 * NULL hostname, or numeric hostname. 519 * If numeric representation of AF1 can be interpreted as FQDN 520 * representation of AF2, we need to think again about the code below. 521 */ 522 found = 0; 523 for (afd = afdl; afd->a_af; afd++) { 524 *pai = ai0; 525 526 if (!MATCH_FAMILY(pai->ai_family, afd->a_af, 1)) 527 continue; 528 529 if (pai->ai_family == PF_UNSPEC) 530 pai->ai_family = afd->a_af; 531 532 if (hostname == NULL) { 533 error = explore_null(pai, servname, 534 &afailist[afd - afdl]); 535 536 /* 537 * Errors from explore_null should be unexpected and 538 * be caught to avoid returning an incomplete result. 539 */ 540 if (error != 0) 541 goto bad; 542 } else { 543 error = explore_numeric_scope(pai, hostname, servname, 544 &afailist[afd - afdl]); 545 546 /* 547 * explore_numeric_scope returns an error for address 548 * families that do not match that of hostname. 549 * Thus we should not catch the error at this moment. 550 */ 551 } 552 553 if (!error && afailist[afd - afdl]) 554 found++; 555 } 556 if (found) { 557 numeric = 1; 558 goto globcopy; 559 } 560 561 if (hostname == NULL) 562 ERR(EAI_NONAME); /* used to be EAI_NODATA */ 563 if (pai->ai_flags & AI_NUMERICHOST) 564 ERR(EAI_NONAME); 565 566 if ((pai->ai_flags & AI_ADDRCONFIG) != 0 && !addrconfig(&ai0)) 567 ERR(EAI_FAIL); 568 569 /* 570 * hostname as alphabetical name. 571 */ 572 *pai = ai0; 573 error = explore_fqdn(pai, hostname, servname, &afai_unspec); 574 575 globcopy: 576 for (ex = explore; ex->e_af >= 0; ex++) { 577 *pai = ai0; 578 579 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex))) 580 continue; 581 if (!MATCH(pai->ai_socktype, ex->e_socktype, 582 WILD_SOCKTYPE(ex))) 583 continue; 584 if (!MATCH(pai->ai_protocol, ex->e_protocol, 585 WILD_PROTOCOL(ex))) 586 continue; 587 588 if (pai->ai_family == PF_UNSPEC) 589 pai->ai_family = ex->e_af; 590 if (pai->ai_socktype == ANY && ex->e_socktype != ANY) 591 pai->ai_socktype = ex->e_socktype; 592 if (pai->ai_protocol == ANY && ex->e_protocol != ANY) 593 pai->ai_protocol = ex->e_protocol; 594 595 /* 596 * if the servname does not match socktype/protocol, ignore it. 597 */ 598 if (get_portmatch(pai, servname) != 0) 599 continue; 600 601 if (afai_unspec) 602 afai = afai_unspec; 603 else { 604 if ((afd = find_afd(pai->ai_family)) == NULL) 605 continue; 606 /* XXX assumes that afd points inside afdl[] */ 607 afai = afailist[afd - afdl]; 608 } 609 if (!afai) 610 continue; 611 612 error = explore_copy(pai, afai, &cur->ai_next); 613 if (error != 0) 614 goto bad; 615 616 while (cur && cur->ai_next) 617 cur = cur->ai_next; 618 } 619 620 /* 621 * ensure we return either: 622 * - error == 0, non-NULL *res 623 * - error != 0, NULL *res 624 */ 625 if (error == 0) { 626 if (sentinel.ai_next) { 627 /* 628 * If the returned entry is for an active connection, 629 * and the given name is not numeric, reorder the 630 * list, so that the application would try the list 631 * in the most efficient order. Since the head entry 632 * of the original list may contain ai_canonname and 633 * that entry may be moved elsewhere in the new list, 634 * we keep the pointer and will restore it in the new 635 * head entry. (Note that RFC3493 requires the head 636 * entry store it when requested by the caller). 637 */ 638 if (hints == NULL || !(hints->ai_flags & AI_PASSIVE)) { 639 if (!numeric) { 640 char *canonname; 641 642 canonname = 643 sentinel.ai_next->ai_canonname; 644 sentinel.ai_next->ai_canonname = NULL; 645 (void)reorder(&sentinel); 646 if (sentinel.ai_next->ai_canonname == 647 NULL) { 648 sentinel.ai_next->ai_canonname 649 = canonname; 650 } else if (canonname != NULL) 651 free(canonname); 652 } 653 } 654 *res = sentinel.ai_next; 655 } else 656 error = EAI_FAIL; 657 } 658 659 bad: 660 if (afai_unspec) 661 freeaddrinfo(afai_unspec); 662 for (afd = afdl; afd->a_af; afd++) { 663 if (afailist[afd - afdl]) 664 freeaddrinfo(afailist[afd - afdl]); 665 } 666 if (!*res) 667 if (sentinel.ai_next) 668 freeaddrinfo(sentinel.ai_next); 669 670 return (error); 671 } 672 673 static int 674 reorder(struct addrinfo *sentinel) 675 { 676 struct addrinfo *ai, **aip; 677 struct ai_order *aio; 678 int i, n; 679 struct policyhead policyhead; 680 681 /* count the number of addrinfo elements for sorting. */ 682 for (n = 0, ai = sentinel->ai_next; ai != NULL; ai = ai->ai_next, n++) 683 ; 684 685 /* 686 * If the number is small enough, we can skip the reordering process. 687 */ 688 if (n <= 1) 689 return(n); 690 691 /* allocate a temporary array for sort and initialization of it. */ 692 if ((aio = calloc(n, sizeof(*aio))) == NULL) 693 return(n); /* give up reordering */ 694 695 /* retrieve address selection policy from the kernel */ 696 TAILQ_INIT(&policyhead); 697 if (!get_addrselectpolicy(&policyhead)) { 698 /* no policy is installed into kernel, we don't sort. */ 699 free(aio); 700 return (n); 701 } 702 703 for (i = 0, ai = sentinel->ai_next; i < n; ai = ai->ai_next, i++) { 704 aio[i].aio_ai = ai; 705 aio[i].aio_dstscope = gai_addr2scopetype(ai->ai_addr); 706 aio[i].aio_dstpolicy = match_addrselectpolicy(ai->ai_addr, 707 &policyhead); 708 set_source(&aio[i], &policyhead); 709 aio[i].aio_initial_sequence = i; 710 } 711 712 /* perform sorting. */ 713 qsort(aio, n, sizeof(*aio), comp_dst); 714 715 /* reorder the addrinfo chain. */ 716 for (i = 0, aip = &sentinel->ai_next; i < n; i++) { 717 *aip = aio[i].aio_ai; 718 aip = &aio[i].aio_ai->ai_next; 719 } 720 *aip = NULL; 721 722 /* cleanup and return */ 723 free(aio); 724 free_addrselectpolicy(&policyhead); 725 return(n); 726 } 727 728 static int 729 get_addrselectpolicy(struct policyhead *head) 730 { 731 #ifdef INET6 732 int mib[] = { CTL_NET, PF_INET6, IPPROTO_IPV6, IPV6CTL_ADDRCTLPOLICY }; 733 size_t l; 734 char *buf; 735 struct in6_addrpolicy *pol, *ep; 736 737 if (sysctl(mib, nitems(mib), NULL, &l, NULL, 0) < 0) 738 return (0); 739 if (l == 0) 740 return (0); 741 if ((buf = malloc(l)) == NULL) 742 return (0); 743 if (sysctl(mib, nitems(mib), buf, &l, NULL, 0) < 0) { 744 free(buf); 745 return (0); 746 } 747 748 ep = (struct in6_addrpolicy *)(buf + l); 749 for (pol = (struct in6_addrpolicy *)buf; pol + 1 <= ep; pol++) { 750 struct policyqueue *new; 751 752 if ((new = malloc(sizeof(*new))) == NULL) { 753 free_addrselectpolicy(head); /* make the list empty */ 754 break; 755 } 756 new->pc_policy = *pol; 757 TAILQ_INSERT_TAIL(head, new, pc_entry); 758 } 759 760 free(buf); 761 return (1); 762 #else 763 return (0); 764 #endif 765 } 766 767 static void 768 free_addrselectpolicy(struct policyhead *head) 769 { 770 struct policyqueue *ent, *nent; 771 772 for (ent = TAILQ_FIRST(head); ent; ent = nent) { 773 nent = TAILQ_NEXT(ent, pc_entry); 774 TAILQ_REMOVE(head, ent, pc_entry); 775 free(ent); 776 } 777 } 778 779 static struct policyqueue * 780 match_addrselectpolicy(struct sockaddr *addr, struct policyhead *head) 781 { 782 #ifdef INET6 783 struct policyqueue *ent, *bestent = NULL; 784 struct in6_addrpolicy *pol; 785 int matchlen, bestmatchlen = -1; 786 u_char *mp, *ep, *k, *p, m; 787 struct sockaddr_in6 key; 788 789 switch(addr->sa_family) { 790 case AF_INET6: 791 key = *(struct sockaddr_in6 *)addr; 792 break; 793 case AF_INET: 794 /* convert the address into IPv4-mapped IPv6 address. */ 795 memset(&key, 0, sizeof(key)); 796 key.sin6_family = AF_INET6; 797 key.sin6_len = sizeof(key); 798 _map_v4v6_address( 799 (char *)&((struct sockaddr_in *)addr)->sin_addr, 800 (char *)&key.sin6_addr); 801 break; 802 default: 803 return(NULL); 804 } 805 806 for (ent = TAILQ_FIRST(head); ent; ent = TAILQ_NEXT(ent, pc_entry)) { 807 pol = &ent->pc_policy; 808 matchlen = 0; 809 810 mp = (u_char *)&pol->addrmask.sin6_addr; 811 ep = mp + 16; /* XXX: scope field? */ 812 k = (u_char *)&key.sin6_addr; 813 p = (u_char *)&pol->addr.sin6_addr; 814 for (; mp < ep && *mp; mp++, k++, p++) { 815 m = *mp; 816 if ((*k & m) != *p) 817 goto next; /* not match */ 818 if (m == 0xff) /* short cut for a typical case */ 819 matchlen += 8; 820 else { 821 while (m >= 0x80) { 822 matchlen++; 823 m <<= 1; 824 } 825 } 826 } 827 828 /* matched. check if this is better than the current best. */ 829 if (matchlen > bestmatchlen) { 830 bestent = ent; 831 bestmatchlen = matchlen; 832 } 833 834 next: 835 continue; 836 } 837 838 return(bestent); 839 #else 840 return(NULL); 841 #endif 842 843 } 844 845 static void 846 set_source(struct ai_order *aio, struct policyhead *ph) 847 { 848 struct addrinfo ai = *aio->aio_ai; 849 struct sockaddr_storage ss; 850 socklen_t srclen; 851 int s; 852 853 /* set unspec ("no source is available"), just in case */ 854 aio->aio_srcsa.sa_family = AF_UNSPEC; 855 aio->aio_srcscope = -1; 856 857 switch(ai.ai_family) { 858 case AF_INET: 859 #ifdef INET6 860 case AF_INET6: 861 #endif 862 break; 863 default: /* ignore unsupported AFs explicitly */ 864 return; 865 } 866 867 /* XXX: make a dummy addrinfo to call connect() */ 868 ai.ai_socktype = SOCK_DGRAM; 869 ai.ai_protocol = IPPROTO_UDP; /* is UDP too specific? */ 870 ai.ai_next = NULL; 871 memset(&ss, 0, sizeof(ss)); 872 memcpy(&ss, ai.ai_addr, ai.ai_addrlen); 873 ai.ai_addr = (struct sockaddr *)&ss; 874 get_port(&ai, "1", 0); 875 876 /* open a socket to get the source address for the given dst */ 877 if ((s = _socket(ai.ai_family, ai.ai_socktype | SOCK_CLOEXEC, 878 ai.ai_protocol)) < 0) 879 return; /* give up */ 880 #ifdef INET6 881 if (ai.ai_family == AF_INET6) { 882 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)ai.ai_addr; 883 int off = 0; 884 885 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 886 (void)_setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, 887 (char *)&off, sizeof(off)); 888 } 889 #endif 890 if (_connect(s, ai.ai_addr, ai.ai_addrlen) < 0) 891 goto cleanup; 892 srclen = ai.ai_addrlen; 893 if (_getsockname(s, &aio->aio_srcsa, &srclen) < 0) { 894 aio->aio_srcsa.sa_family = AF_UNSPEC; 895 goto cleanup; 896 } 897 aio->aio_srcscope = gai_addr2scopetype(&aio->aio_srcsa); 898 aio->aio_srcpolicy = match_addrselectpolicy(&aio->aio_srcsa, ph); 899 aio->aio_matchlen = matchlen(&aio->aio_srcsa, aio->aio_ai->ai_addr); 900 #ifdef INET6 901 if (ai.ai_family == AF_INET6) { 902 struct in6_ifreq ifr6; 903 u_int32_t flags6; 904 905 memset(&ifr6, 0, sizeof(ifr6)); 906 memcpy(&ifr6.ifr_addr, ai.ai_addr, ai.ai_addrlen); 907 if (_ioctl(s, SIOCGIFAFLAG_IN6, &ifr6) == 0) { 908 flags6 = ifr6.ifr_ifru.ifru_flags6; 909 if ((flags6 & IN6_IFF_DEPRECATED)) 910 aio->aio_srcflag |= AIO_SRCFLAG_DEPRECATED; 911 } 912 } 913 #endif 914 915 cleanup: 916 _close(s); 917 return; 918 } 919 920 static int 921 matchlen(struct sockaddr *src, struct sockaddr *dst) 922 { 923 int match = 0; 924 u_char *s, *d; 925 u_char *lim, r; 926 int addrlen; 927 928 switch (src->sa_family) { 929 #ifdef INET6 930 case AF_INET6: 931 s = (u_char *)&((struct sockaddr_in6 *)src)->sin6_addr; 932 d = (u_char *)&((struct sockaddr_in6 *)dst)->sin6_addr; 933 addrlen = sizeof(struct in6_addr); 934 lim = s + addrlen; 935 break; 936 #endif 937 case AF_INET: 938 s = (u_char *)&((struct sockaddr_in *)src)->sin_addr; 939 d = (u_char *)&((struct sockaddr_in *)dst)->sin_addr; 940 addrlen = sizeof(struct in_addr); 941 lim = s + addrlen; 942 break; 943 default: 944 return(0); 945 } 946 947 while (s < lim) 948 if ((r = (*d++ ^ *s++)) != 0) { 949 while ((r & 0x80) == 0) { 950 match++; 951 r <<= 1; 952 } 953 break; 954 } else 955 match += 8; 956 return(match); 957 } 958 959 static int 960 comp_dst(const void *arg1, const void *arg2) 961 { 962 const struct ai_order *dst1 = arg1, *dst2 = arg2; 963 964 /* 965 * Rule 1: Avoid unusable destinations. 966 * XXX: we currently do not consider if an appropriate route exists. 967 */ 968 if (dst1->aio_srcsa.sa_family != AF_UNSPEC && 969 dst2->aio_srcsa.sa_family == AF_UNSPEC) { 970 return(-1); 971 } 972 if (dst1->aio_srcsa.sa_family == AF_UNSPEC && 973 dst2->aio_srcsa.sa_family != AF_UNSPEC) { 974 return(1); 975 } 976 977 /* Rule 2: Prefer matching scope. */ 978 if (dst1->aio_dstscope == dst1->aio_srcscope && 979 dst2->aio_dstscope != dst2->aio_srcscope) { 980 return(-1); 981 } 982 if (dst1->aio_dstscope != dst1->aio_srcscope && 983 dst2->aio_dstscope == dst2->aio_srcscope) { 984 return(1); 985 } 986 987 /* Rule 3: Avoid deprecated addresses. */ 988 if (dst1->aio_srcsa.sa_family != AF_UNSPEC && 989 dst2->aio_srcsa.sa_family != AF_UNSPEC) { 990 if (!(dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) && 991 (dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) { 992 return(-1); 993 } 994 if ((dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) && 995 !(dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) { 996 return(1); 997 } 998 } 999 1000 /* Rule 4: Prefer home addresses. */ 1001 /* XXX: not implemented yet */ 1002 1003 /* Rule 5: Prefer matching label. */ 1004 #ifdef INET6 1005 if (dst1->aio_srcpolicy && dst1->aio_dstpolicy && 1006 dst1->aio_srcpolicy->pc_policy.label == 1007 dst1->aio_dstpolicy->pc_policy.label && 1008 (dst2->aio_srcpolicy == NULL || dst2->aio_dstpolicy == NULL || 1009 dst2->aio_srcpolicy->pc_policy.label != 1010 dst2->aio_dstpolicy->pc_policy.label)) { 1011 return(-1); 1012 } 1013 if (dst2->aio_srcpolicy && dst2->aio_dstpolicy && 1014 dst2->aio_srcpolicy->pc_policy.label == 1015 dst2->aio_dstpolicy->pc_policy.label && 1016 (dst1->aio_srcpolicy == NULL || dst1->aio_dstpolicy == NULL || 1017 dst1->aio_srcpolicy->pc_policy.label != 1018 dst1->aio_dstpolicy->pc_policy.label)) { 1019 return(1); 1020 } 1021 #endif 1022 1023 /* Rule 6: Prefer higher precedence. */ 1024 #ifdef INET6 1025 if (dst1->aio_dstpolicy && 1026 (dst2->aio_dstpolicy == NULL || 1027 dst1->aio_dstpolicy->pc_policy.preced > 1028 dst2->aio_dstpolicy->pc_policy.preced)) { 1029 return(-1); 1030 } 1031 if (dst2->aio_dstpolicy && 1032 (dst1->aio_dstpolicy == NULL || 1033 dst2->aio_dstpolicy->pc_policy.preced > 1034 dst1->aio_dstpolicy->pc_policy.preced)) { 1035 return(1); 1036 } 1037 #endif 1038 1039 /* Rule 7: Prefer native transport. */ 1040 /* XXX: not implemented yet */ 1041 1042 /* Rule 8: Prefer smaller scope. */ 1043 if (dst1->aio_dstscope >= 0 && 1044 dst1->aio_dstscope < dst2->aio_dstscope) { 1045 return(-1); 1046 } 1047 if (dst2->aio_dstscope >= 0 && 1048 dst2->aio_dstscope < dst1->aio_dstscope) { 1049 return(1); 1050 } 1051 1052 /* 1053 * Rule 9: Use longest matching prefix. 1054 * We compare the match length in a same AF only. 1055 */ 1056 if (dst1->aio_ai->ai_addr->sa_family == 1057 dst2->aio_ai->ai_addr->sa_family && 1058 dst1->aio_ai->ai_addr->sa_family != AF_INET) { 1059 if (dst1->aio_matchlen > dst2->aio_matchlen) { 1060 return(-1); 1061 } 1062 if (dst1->aio_matchlen < dst2->aio_matchlen) { 1063 return(1); 1064 } 1065 } 1066 1067 /* Rule 10: Otherwise, leave the order unchanged. */ 1068 1069 /* 1070 * Note that qsort is unstable; so, we can't return zero and 1071 * expect the order to be unchanged. 1072 * That also means we can't depend on the current position of 1073 * dst2 being after dst1. We must enforce the initial order 1074 * with an explicit compare on the original position. 1075 * The qsort specification requires that "When the same objects 1076 * (consisting of width bytes, irrespective of their current 1077 * positions in the array) are passed more than once to the 1078 * comparison function, the results shall be consistent with one 1079 * another." 1080 * In other words, If A < B, then we must also return B > A. 1081 */ 1082 if (dst2->aio_initial_sequence < dst1->aio_initial_sequence) 1083 return(1); 1084 1085 return(-1); 1086 } 1087 1088 /* 1089 * Copy from scope.c. 1090 * XXX: we should standardize the functions and link them as standard 1091 * library. 1092 */ 1093 static int 1094 gai_addr2scopetype(struct sockaddr *sa) 1095 { 1096 #ifdef INET6 1097 struct sockaddr_in6 *sa6; 1098 #endif 1099 struct sockaddr_in *sa4; 1100 1101 switch(sa->sa_family) { 1102 #ifdef INET6 1103 case AF_INET6: 1104 sa6 = (struct sockaddr_in6 *)sa; 1105 if (IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) { 1106 /* just use the scope field of the multicast address */ 1107 return(sa6->sin6_addr.s6_addr[2] & 0x0f); 1108 } 1109 /* 1110 * Unicast addresses: map scope type to corresponding scope 1111 * value defined for multcast addresses. 1112 * XXX: hardcoded scope type values are bad... 1113 */ 1114 if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr)) 1115 return(1); /* node local scope */ 1116 if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr)) 1117 return(2); /* link-local scope */ 1118 if (IN6_IS_ADDR_SITELOCAL(&sa6->sin6_addr)) 1119 return(5); /* site-local scope */ 1120 return(14); /* global scope */ 1121 break; 1122 #endif 1123 case AF_INET: 1124 /* 1125 * IPv4 pseudo scoping according to RFC 3484. 1126 */ 1127 sa4 = (struct sockaddr_in *)sa; 1128 /* IPv4 autoconfiguration addresses have link-local scope. */ 1129 if (((u_char *)&sa4->sin_addr)[0] == 169 && 1130 ((u_char *)&sa4->sin_addr)[1] == 254) 1131 return(2); 1132 /* Private addresses have site-local scope. */ 1133 if (((u_char *)&sa4->sin_addr)[0] == 10 || 1134 (((u_char *)&sa4->sin_addr)[0] == 172 && 1135 (((u_char *)&sa4->sin_addr)[1] & 0xf0) == 16) || 1136 (((u_char *)&sa4->sin_addr)[0] == 192 && 1137 ((u_char *)&sa4->sin_addr)[1] == 168)) 1138 return(14); /* XXX: It should be 5 unless NAT */ 1139 /* Loopback addresses have link-local scope. */ 1140 if (((u_char *)&sa4->sin_addr)[0] == 127) 1141 return(2); 1142 return(14); 1143 break; 1144 default: 1145 errno = EAFNOSUPPORT; /* is this a good error? */ 1146 return(-1); 1147 } 1148 } 1149 1150 static int 1151 explore_copy(const struct addrinfo *pai, const struct addrinfo *src0, 1152 struct addrinfo **res) 1153 { 1154 int error; 1155 struct addrinfo sentinel, *cur; 1156 const struct addrinfo *src; 1157 1158 error = 0; 1159 sentinel.ai_next = NULL; 1160 cur = &sentinel; 1161 1162 for (src = src0; src != NULL; src = src->ai_next) { 1163 if (src->ai_family != pai->ai_family) 1164 continue; 1165 1166 cur->ai_next = copy_ai(src); 1167 if (!cur->ai_next) { 1168 error = EAI_MEMORY; 1169 goto fail; 1170 } 1171 1172 cur->ai_next->ai_socktype = pai->ai_socktype; 1173 cur->ai_next->ai_protocol = pai->ai_protocol; 1174 cur = cur->ai_next; 1175 } 1176 1177 *res = sentinel.ai_next; 1178 return 0; 1179 1180 fail: 1181 freeaddrinfo(sentinel.ai_next); 1182 return error; 1183 } 1184 1185 /* 1186 * hostname == NULL. 1187 * passive socket -> anyaddr (0.0.0.0 or ::) 1188 * non-passive socket -> localhost (127.0.0.1 or ::1) 1189 */ 1190 static int 1191 explore_null(const struct addrinfo *pai, const char *servname, 1192 struct addrinfo **res) 1193 { 1194 int s; 1195 const struct afd *afd; 1196 struct addrinfo *ai; 1197 int error; 1198 1199 *res = NULL; 1200 ai = NULL; 1201 1202 if (pai->ai_family == PF_LOCAL) 1203 return (0); 1204 1205 /* 1206 * filter out AFs that are not supported by the kernel 1207 * XXX errno? 1208 */ 1209 s = _socket(pai->ai_family, SOCK_DGRAM | SOCK_CLOEXEC, 0); 1210 if (s < 0) { 1211 if (errno != EMFILE) 1212 return 0; 1213 } else 1214 _close(s); 1215 1216 afd = find_afd(pai->ai_family); 1217 if (afd == NULL) 1218 return 0; 1219 1220 if (pai->ai_flags & AI_PASSIVE) { 1221 GET_AI(ai, afd, afd->a_addrany); 1222 GET_PORT(ai, servname); 1223 } else { 1224 GET_AI(ai, afd, afd->a_loopback); 1225 GET_PORT(ai, servname); 1226 } 1227 1228 *res = ai; 1229 return 0; 1230 1231 free: 1232 if (ai != NULL) 1233 freeaddrinfo(ai); 1234 return error; 1235 } 1236 1237 /* 1238 * numeric hostname 1239 */ 1240 static int 1241 explore_numeric(const struct addrinfo *pai, const char *hostname, 1242 const char *servname, struct addrinfo **res, const char *canonname) 1243 { 1244 const struct afd *afd; 1245 struct addrinfo *ai, ai0; 1246 int error; 1247 char pton[PTON_MAX], path[PATH_MAX], *p; 1248 1249 #ifdef CTASSERT 1250 CTASSERT(sizeofmember(struct sockaddr_un, sun_path) <= PATH_MAX); 1251 #endif 1252 *res = NULL; 1253 ai = NULL; 1254 1255 afd = find_afd(pai->ai_family); 1256 if (afd == NULL) 1257 return 0; 1258 1259 switch (afd->a_af) { 1260 case AF_LOCAL: 1261 if (hostname[0] != '/') 1262 ERR(EAI_NONAME); 1263 if (strlen(hostname) > afd->a_addrlen) 1264 ERR(EAI_MEMORY); 1265 /* NUL-termination does not need to be guaranteed. */ 1266 strncpy(path, hostname, afd->a_addrlen); 1267 p = &path[0]; 1268 break; 1269 case AF_INET: 1270 /* 1271 * RFC3493 requires getaddrinfo() to accept AF_INET formats 1272 * that are accepted by inet_addr() and its family. The 1273 * accepted forms includes the "classful" one, which inet_pton 1274 * does not accept. So we need to separate the case for 1275 * AF_INET. 1276 */ 1277 if (inet_aton(hostname, (struct in_addr *)pton) != 1 || 1278 hostname[strspn(hostname, "0123456789.xabcdefXABCDEF")] != '\0') 1279 return 0; 1280 p = pton; 1281 break; 1282 default: 1283 if (inet_pton(afd->a_af, hostname, pton) != 1) { 1284 if (pai->ai_family != AF_INET6 || 1285 (pai->ai_flags & AI_V4MAPPED) != AI_V4MAPPED) 1286 return 0; 1287 if (inet_aton(hostname, (struct in_addr *)pton) != 1) 1288 return 0; 1289 afd = &afdl[N_INET]; 1290 ai0 = *pai; 1291 ai0.ai_family = AF_INET; 1292 pai = &ai0; 1293 } 1294 p = pton; 1295 break; 1296 } 1297 1298 if (pai->ai_family == afd->a_af) { 1299 GET_AI(ai, afd, p); 1300 GET_PORT(ai, servname); 1301 if ((pai->ai_family == AF_INET || 1302 pai->ai_family == AF_INET6) && 1303 (pai->ai_flags & AI_CANONNAME)) { 1304 /* 1305 * Set the numeric address itself as the canonical 1306 * name, based on a clarification in RFC3493. 1307 */ 1308 GET_CANONNAME(ai, canonname); 1309 } 1310 } else { 1311 /* 1312 * XXX: This should not happen since we already matched the AF 1313 * by find_afd. 1314 */ 1315 ERR(EAI_FAMILY); 1316 } 1317 1318 *res = ai; 1319 return 0; 1320 1321 free: 1322 bad: 1323 if (ai != NULL) 1324 freeaddrinfo(ai); 1325 return error; 1326 } 1327 1328 /* 1329 * numeric hostname with scope 1330 */ 1331 static int 1332 explore_numeric_scope(const struct addrinfo *pai, const char *hostname, 1333 const char *servname, struct addrinfo **res) 1334 { 1335 #if !defined(SCOPE_DELIMITER) || !defined(INET6) 1336 return explore_numeric(pai, hostname, servname, res, hostname); 1337 #else 1338 const struct afd *afd; 1339 struct addrinfo *cur; 1340 int error; 1341 char *hostname2 = NULL, *addr; 1342 const char *cp, *scope; 1343 struct sockaddr_in6 *sin6; 1344 1345 afd = find_afd(pai->ai_family); 1346 if (afd == NULL) 1347 return 0; 1348 1349 if (!afd->a_scoped) 1350 return explore_numeric(pai, hostname, servname, res, hostname); 1351 1352 cp = strchr(hostname, SCOPE_DELIMITER); 1353 if (cp == NULL) 1354 return explore_numeric(pai, hostname, servname, res, hostname); 1355 1356 /* 1357 * Handle special case of <scoped_address><delimiter><scope id> 1358 */ 1359 hostname2 = strdup(hostname); 1360 if (hostname2 == NULL) 1361 return EAI_MEMORY; 1362 /* terminate at the delimiter */ 1363 hostname2[cp - hostname] = '\0'; 1364 addr = hostname2; 1365 scope = cp + 1; 1366 1367 error = explore_numeric(pai, addr, servname, res, hostname); 1368 if (error == 0) { 1369 u_int32_t scopeid; 1370 1371 for (cur = *res; cur; cur = cur->ai_next) { 1372 if (cur->ai_family != AF_INET6) 1373 continue; 1374 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr; 1375 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) { 1376 free(hostname2); 1377 freeaddrinfo(*res); 1378 *res = NULL; 1379 return(EAI_NONAME); /* XXX: is return OK? */ 1380 } 1381 sin6->sin6_scope_id = scopeid; 1382 } 1383 } 1384 1385 free(hostname2); 1386 1387 if (error && *res) { 1388 freeaddrinfo(*res); 1389 *res = NULL; 1390 } 1391 return error; 1392 #endif 1393 } 1394 1395 static int 1396 get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str) 1397 { 1398 if ((pai->ai_flags & AI_CANONNAME) != 0) { 1399 ai->ai_canonname = strdup(str); 1400 if (ai->ai_canonname == NULL) 1401 return EAI_MEMORY; 1402 } 1403 return 0; 1404 } 1405 1406 static struct addrinfo * 1407 get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr) 1408 { 1409 char *p; 1410 struct addrinfo *ai; 1411 #ifdef INET6 1412 struct in6_addr mapaddr; 1413 1414 if (afd->a_af == AF_INET && (pai->ai_flags & AI_V4MAPPED) != 0) { 1415 afd = &afdl[N_INET6]; 1416 _map_v4v6_address(addr, (char *)&mapaddr); 1417 addr = (char *)&mapaddr; 1418 } 1419 #endif 1420 1421 ai = (struct addrinfo *)malloc(sizeof(struct addrinfo) 1422 + (afd->a_socklen)); 1423 if (ai == NULL) 1424 return NULL; 1425 1426 memcpy(ai, pai, sizeof(struct addrinfo)); 1427 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1); 1428 memset(ai->ai_addr, 0, (size_t)afd->a_socklen); 1429 ai->ai_addr->sa_len = afd->a_socklen; 1430 ai->ai_addrlen = afd->a_socklen; 1431 if (ai->ai_family == PF_LOCAL) { 1432 size_t n = strnlen(addr, afd->a_addrlen); 1433 1434 ai->ai_addrlen -= afd->a_addrlen - n; 1435 ai->ai_addr->sa_len -= afd->a_addrlen - n; 1436 } 1437 ai->ai_addr->sa_family = ai->ai_family = afd->a_af; 1438 p = (char *)(void *)(ai->ai_addr); 1439 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen); 1440 return ai; 1441 } 1442 1443 /* XXX need to malloc() the same way we do from other functions! */ 1444 static struct addrinfo * 1445 copy_ai(const struct addrinfo *pai) 1446 { 1447 struct addrinfo *ai; 1448 size_t l; 1449 1450 l = sizeof(*ai) + pai->ai_addrlen; 1451 if ((ai = calloc(1, l)) == NULL) 1452 return NULL; 1453 memcpy(ai, pai, sizeof(*ai)); 1454 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1); 1455 memcpy(ai->ai_addr, pai->ai_addr, pai->ai_addrlen); 1456 1457 if (pai->ai_canonname) { 1458 l = strlen(pai->ai_canonname) + 1; 1459 if ((ai->ai_canonname = malloc(l)) == NULL) { 1460 free(ai); 1461 return NULL; 1462 } 1463 strlcpy(ai->ai_canonname, pai->ai_canonname, l); 1464 } else { 1465 /* just to make sure */ 1466 ai->ai_canonname = NULL; 1467 } 1468 1469 ai->ai_next = NULL; 1470 1471 return ai; 1472 } 1473 1474 static int 1475 get_portmatch(const struct addrinfo *ai, const char *servname) 1476 { 1477 1478 /* get_port does not touch first argument when matchonly == 1. */ 1479 /* LINTED const cast */ 1480 return get_port((struct addrinfo *)ai, servname, 1); 1481 } 1482 1483 static int 1484 get_port(struct addrinfo *ai, const char *servname, int matchonly) 1485 { 1486 const char *proto; 1487 struct servent *sp; 1488 int port, error; 1489 int allownumeric; 1490 1491 if (servname == NULL) 1492 return 0; 1493 switch (ai->ai_family) { 1494 case AF_LOCAL: 1495 /* AF_LOCAL ignores servname silently. */ 1496 return (0); 1497 case AF_INET: 1498 #ifdef AF_INET6 1499 case AF_INET6: 1500 #endif 1501 break; 1502 default: 1503 return 0; 1504 } 1505 1506 switch (ai->ai_socktype) { 1507 case SOCK_RAW: 1508 return EAI_SERVICE; 1509 case SOCK_DGRAM: 1510 case SOCK_STREAM: 1511 case SOCK_SEQPACKET: 1512 allownumeric = 1; 1513 break; 1514 case ANY: 1515 switch (ai->ai_family) { 1516 case AF_INET: 1517 #ifdef AF_INET6 1518 case AF_INET6: 1519 #endif 1520 allownumeric = 1; 1521 break; 1522 default: 1523 allownumeric = 0; 1524 break; 1525 } 1526 break; 1527 default: 1528 return EAI_SOCKTYPE; 1529 } 1530 1531 error = str2number(servname, &port); 1532 if (error == 0) { 1533 if (!allownumeric) 1534 return EAI_SERVICE; 1535 if (port < 0 || port > 65535) 1536 return EAI_SERVICE; 1537 port = htons(port); 1538 } else { 1539 if (ai->ai_flags & AI_NUMERICSERV) 1540 return EAI_NONAME; 1541 1542 switch (ai->ai_protocol) { 1543 case IPPROTO_UDP: 1544 proto = "udp"; 1545 break; 1546 case IPPROTO_TCP: 1547 proto = "tcp"; 1548 break; 1549 case IPPROTO_SCTP: 1550 proto = "sctp"; 1551 break; 1552 case IPPROTO_UDPLITE: 1553 proto = "udplite"; 1554 break; 1555 default: 1556 proto = NULL; 1557 break; 1558 } 1559 1560 if ((sp = getservbyname(servname, proto)) == NULL) 1561 return EAI_SERVICE; 1562 port = sp->s_port; 1563 } 1564 1565 if (!matchonly) { 1566 switch (ai->ai_family) { 1567 case AF_INET: 1568 ((struct sockaddr_in *)(void *) 1569 ai->ai_addr)->sin_port = port; 1570 break; 1571 #ifdef INET6 1572 case AF_INET6: 1573 ((struct sockaddr_in6 *)(void *) 1574 ai->ai_addr)->sin6_port = port; 1575 break; 1576 #endif 1577 } 1578 } 1579 1580 return 0; 1581 } 1582 1583 static const struct afd * 1584 find_afd(int af) 1585 { 1586 const struct afd *afd; 1587 1588 if (af == PF_UNSPEC) 1589 return NULL; 1590 for (afd = afdl; afd->a_af; afd++) { 1591 if (afd->a_af == af) 1592 return afd; 1593 } 1594 return NULL; 1595 } 1596 1597 /* 1598 * RFC 3493: AI_ADDRCONFIG check. Determines which address families are 1599 * configured on the local system and correlates with pai->ai_family value. 1600 * If an address family is not configured on the system, it will not be 1601 * queried for. For this purpose, loopback addresses are not considered 1602 * configured addresses. 1603 * 1604 * XXX PF_UNSPEC -> PF_INET6 + PF_INET mapping needs to be in sync with 1605 * _dns_getaddrinfo. 1606 */ 1607 static int 1608 addrconfig(struct addrinfo *pai) 1609 { 1610 struct ifaddrs *ifaddrs, *ifa; 1611 struct sockaddr_in *sin; 1612 #ifdef INET6 1613 struct sockaddr_in6 *sin6; 1614 #endif 1615 int seen_inet = 0, seen_inet6 = 0; 1616 1617 if (getifaddrs(&ifaddrs) != 0) 1618 return (0); 1619 1620 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 1621 if (ifa->ifa_addr == NULL || (ifa->ifa_flags & IFF_UP) == 0) 1622 continue; 1623 switch (ifa->ifa_addr->sa_family) { 1624 case AF_INET: 1625 if (seen_inet) 1626 continue; 1627 sin = (struct sockaddr_in *)(ifa->ifa_addr); 1628 if (htonl(sin->sin_addr.s_addr) == INADDR_LOOPBACK) 1629 continue; 1630 seen_inet = 1; 1631 break; 1632 #ifdef INET6 1633 case AF_INET6: 1634 if (seen_inet6) 1635 continue; 1636 sin6 = (struct sockaddr_in6 *)(ifa->ifa_addr); 1637 if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr)) 1638 continue; 1639 if ((ifa->ifa_flags & IFT_LOOP) != 0 && 1640 IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) 1641 continue; 1642 if (is_ifdisabled(ifa->ifa_name)) 1643 continue; 1644 seen_inet6 = 1; 1645 break; 1646 #endif 1647 } 1648 } 1649 freeifaddrs(ifaddrs); 1650 1651 switch(pai->ai_family) { 1652 case AF_INET6: 1653 return (seen_inet6); 1654 case AF_INET: 1655 return (seen_inet); 1656 case AF_UNSPEC: 1657 if (seen_inet == seen_inet6) 1658 return (seen_inet); 1659 pai->ai_family = seen_inet ? AF_INET : AF_INET6; 1660 return (1); 1661 } 1662 return (1); 1663 } 1664 1665 #ifdef INET6 1666 static int 1667 is_ifdisabled(char *name) 1668 { 1669 struct in6_ndireq nd; 1670 int fd; 1671 1672 if ((fd = _socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0)) < 0) 1673 return (-1); 1674 memset(&nd, 0, sizeof(nd)); 1675 strlcpy(nd.ifname, name, sizeof(nd.ifname)); 1676 if (_ioctl(fd, SIOCGIFINFO_IN6, &nd) < 0) { 1677 _close(fd); 1678 return (-1); 1679 } 1680 _close(fd); 1681 return ((nd.ndi.flags & ND6_IFF_IFDISABLED) != 0); 1682 } 1683 1684 /* convert a string to a scope identifier. XXX: IPv6 specific */ 1685 static int 1686 ip6_str2scopeid(const char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid) 1687 { 1688 u_long lscopeid; 1689 struct in6_addr *a6; 1690 char *ep; 1691 1692 a6 = &sin6->sin6_addr; 1693 1694 /* empty scopeid portion is invalid */ 1695 if (*scope == '\0') 1696 return -1; 1697 1698 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 1699 IN6_IS_ADDR_MC_NODELOCAL(a6)) { 1700 /* 1701 * We currently assume a one-to-one mapping between links 1702 * and interfaces, so we simply use interface indices for 1703 * like-local scopes. 1704 */ 1705 *scopeid = if_nametoindex(scope); 1706 if (*scopeid == 0) 1707 goto trynumeric; 1708 return 0; 1709 } 1710 1711 /* still unclear about literal, allow numeric only - placeholder */ 1712 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6)) 1713 goto trynumeric; 1714 if (IN6_IS_ADDR_MC_ORGLOCAL(a6)) 1715 goto trynumeric; 1716 else 1717 goto trynumeric; /* global */ 1718 1719 /* try to convert to a numeric id as a last resort */ 1720 trynumeric: 1721 errno = 0; 1722 lscopeid = strtoul(scope, &ep, 10); 1723 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL); 1724 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid) 1725 return 0; 1726 else 1727 return -1; 1728 } 1729 #endif 1730 1731 1732 #ifdef NS_CACHING 1733 static int 1734 addrinfo_id_func(char *buffer, size_t *buffer_size, va_list ap, 1735 void *cache_mdata) 1736 { 1737 res_state statp; 1738 u_long res_options; 1739 1740 const int op_id = 0; /* identifies the getaddrinfo for the cache */ 1741 char *hostname; 1742 struct addrinfo *hints; 1743 1744 char *p; 1745 int ai_flags, ai_family, ai_socktype, ai_protocol; 1746 size_t desired_size, size; 1747 1748 statp = __res_state(); 1749 res_options = statp->options & (RES_RECURSE | RES_DEFNAMES | 1750 RES_DNSRCH | RES_NOALIASES | RES_USE_INET6); 1751 1752 hostname = va_arg(ap, char *); 1753 hints = va_arg(ap, struct addrinfo *); 1754 1755 desired_size = sizeof(res_options) + sizeof(int) + sizeof(int) * 4; 1756 if (hostname != NULL) { 1757 size = strlen(hostname); 1758 desired_size += size + 1; 1759 } else 1760 size = 0; 1761 1762 if (desired_size > *buffer_size) { 1763 *buffer_size = desired_size; 1764 return (NS_RETURN); 1765 } 1766 1767 if (hints == NULL) 1768 ai_flags = ai_family = ai_socktype = ai_protocol = 0; 1769 else { 1770 ai_flags = hints->ai_flags; 1771 ai_family = hints->ai_family; 1772 ai_socktype = hints->ai_socktype; 1773 ai_protocol = hints->ai_protocol; 1774 } 1775 1776 p = buffer; 1777 memcpy(p, &res_options, sizeof(res_options)); 1778 p += sizeof(res_options); 1779 1780 memcpy(p, &op_id, sizeof(int)); 1781 p += sizeof(int); 1782 1783 memcpy(p, &ai_flags, sizeof(int)); 1784 p += sizeof(int); 1785 1786 memcpy(p, &ai_family, sizeof(int)); 1787 p += sizeof(int); 1788 1789 memcpy(p, &ai_socktype, sizeof(int)); 1790 p += sizeof(int); 1791 1792 memcpy(p, &ai_protocol, sizeof(int)); 1793 p += sizeof(int); 1794 1795 if (hostname != NULL) 1796 memcpy(p, hostname, size); 1797 1798 *buffer_size = desired_size; 1799 return (NS_SUCCESS); 1800 } 1801 1802 static int 1803 addrinfo_marshal_func(char *buffer, size_t *buffer_size, void *retval, 1804 va_list ap, void *cache_mdata) 1805 { 1806 struct addrinfo *ai, *cai; 1807 char *p; 1808 size_t desired_size, size, ai_size; 1809 1810 ai = *((struct addrinfo **)retval); 1811 1812 desired_size = sizeof(size_t); 1813 ai_size = 0; 1814 for (cai = ai; cai != NULL; cai = cai->ai_next) { 1815 desired_size += sizeof(struct addrinfo) + cai->ai_addrlen; 1816 if (cai->ai_canonname != NULL) 1817 desired_size += sizeof(size_t) + 1818 strlen(cai->ai_canonname); 1819 ++ai_size; 1820 } 1821 1822 if (desired_size > *buffer_size) { 1823 /* this assignment is here for future use */ 1824 errno = ERANGE; 1825 *buffer_size = desired_size; 1826 return (NS_RETURN); 1827 } 1828 1829 memset(buffer, 0, desired_size); 1830 p = buffer; 1831 1832 memcpy(p, &ai_size, sizeof(size_t)); 1833 p += sizeof(size_t); 1834 for (cai = ai; cai != NULL; cai = cai->ai_next) { 1835 memcpy(p, cai, sizeof(struct addrinfo)); 1836 p += sizeof(struct addrinfo); 1837 1838 memcpy(p, cai->ai_addr, cai->ai_addrlen); 1839 p += cai->ai_addrlen; 1840 1841 if (cai->ai_canonname != NULL) { 1842 size = strlen(cai->ai_canonname); 1843 memcpy(p, &size, sizeof(size_t)); 1844 p += sizeof(size_t); 1845 1846 memcpy(p, cai->ai_canonname, size); 1847 p += size; 1848 } 1849 } 1850 1851 return (NS_SUCCESS); 1852 } 1853 1854 static int 1855 addrinfo_unmarshal_func(char *buffer, size_t buffer_size, void *retval, 1856 va_list ap, void *cache_mdata) 1857 { 1858 struct addrinfo new_ai, *result, *sentinel, *lasts; 1859 1860 char *p; 1861 size_t ai_size, ai_i, size; 1862 1863 p = buffer; 1864 memcpy(&ai_size, p, sizeof(size_t)); 1865 p += sizeof(size_t); 1866 1867 result = NULL; 1868 lasts = NULL; 1869 for (ai_i = 0; ai_i < ai_size; ++ai_i) { 1870 memcpy(&new_ai, p, sizeof(struct addrinfo)); 1871 p += sizeof(struct addrinfo); 1872 size = new_ai.ai_addrlen + sizeof(struct addrinfo) + 1873 _ALIGNBYTES; 1874 1875 sentinel = calloc(1, size); 1876 1877 memcpy(sentinel, &new_ai, sizeof(struct addrinfo)); 1878 sentinel->ai_addr = (struct sockaddr *)_ALIGN((char *)sentinel + 1879 sizeof(struct addrinfo)); 1880 1881 memcpy(sentinel->ai_addr, p, new_ai.ai_addrlen); 1882 p += new_ai.ai_addrlen; 1883 1884 if (new_ai.ai_canonname != NULL) { 1885 memcpy(&size, p, sizeof(size_t)); 1886 p += sizeof(size_t); 1887 1888 sentinel->ai_canonname = calloc(1, size + 1); 1889 1890 memcpy(sentinel->ai_canonname, p, size); 1891 p += size; 1892 } 1893 1894 if (result == NULL) { 1895 result = sentinel; 1896 lasts = sentinel; 1897 } else { 1898 lasts->ai_next = sentinel; 1899 lasts = sentinel; 1900 } 1901 } 1902 1903 *((struct addrinfo **)retval) = result; 1904 return (NS_SUCCESS); 1905 } 1906 #endif /* NS_CACHING */ 1907 1908 /* 1909 * FQDN hostname, DNS lookup 1910 */ 1911 static int 1912 explore_fqdn(const struct addrinfo *pai, const char *hostname, 1913 const char *servname, struct addrinfo **res) 1914 { 1915 struct addrinfo *result; 1916 struct addrinfo *cur; 1917 int error = 0; 1918 1919 #ifdef NS_CACHING 1920 static const nss_cache_info cache_info = 1921 NS_COMMON_CACHE_INFO_INITIALIZER( 1922 hosts, NULL, addrinfo_id_func, addrinfo_marshal_func, 1923 addrinfo_unmarshal_func); 1924 #endif 1925 static const ns_dtab dtab[] = { 1926 NS_FILES_CB(_files_getaddrinfo, NULL) 1927 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */ 1928 NS_NIS_CB(_yp_getaddrinfo, NULL) 1929 #ifdef NS_CACHING 1930 NS_CACHE_CB(&cache_info) 1931 #endif 1932 { 0 } 1933 }; 1934 1935 result = NULL; 1936 1937 /* 1938 * if the servname does not match socktype/protocol, ignore it. 1939 */ 1940 if (get_portmatch(pai, servname) != 0) 1941 return 0; 1942 1943 switch (_nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo", 1944 default_dns_files, hostname, pai)) { 1945 case NS_TRYAGAIN: 1946 error = EAI_AGAIN; 1947 goto free; 1948 case NS_UNAVAIL: 1949 error = EAI_FAIL; 1950 goto free; 1951 case NS_NOTFOUND: 1952 error = EAI_NONAME; 1953 goto free; 1954 case NS_ADDRFAMILY: 1955 error = EAI_ADDRFAMILY; 1956 goto free; 1957 case NS_SUCCESS: 1958 error = 0; 1959 for (cur = result; cur; cur = cur->ai_next) { 1960 GET_PORT(cur, servname); 1961 /* canonname should be filled already */ 1962 } 1963 break; 1964 } 1965 1966 *res = result; 1967 1968 return 0; 1969 1970 free: 1971 if (result) 1972 freeaddrinfo(result); 1973 return error; 1974 } 1975 1976 #ifdef DEBUG 1977 static const char AskedForGot[] = 1978 "gethostby*.getanswer: asked for \"%s\", got \"%s\""; 1979 #endif 1980 1981 static struct addrinfo * 1982 getanswer(const querybuf *answer, int anslen, const char *qname, int qtype, 1983 const struct addrinfo *pai, res_state res) 1984 { 1985 struct addrinfo sentinel, *cur; 1986 struct addrinfo ai; 1987 const struct afd *afd; 1988 char *canonname; 1989 const HEADER *hp; 1990 const u_char *cp; 1991 int n; 1992 const u_char *eom; 1993 char *bp, *ep; 1994 int type, class, ancount, qdcount; 1995 int haveanswer, had_error; 1996 char tbuf[MAXDNAME]; 1997 int (*name_ok)(const char *); 1998 char hostbuf[8*1024]; 1999 2000 memset(&sentinel, 0, sizeof(sentinel)); 2001 cur = &sentinel; 2002 2003 canonname = NULL; 2004 eom = answer->buf + anslen; 2005 switch (qtype) { 2006 case T_A: 2007 case T_AAAA: 2008 case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/ 2009 name_ok = res_hnok; 2010 break; 2011 default: 2012 return (NULL); /* XXX should be abort(); */ 2013 } 2014 /* 2015 * find first satisfactory answer 2016 */ 2017 hp = &answer->hdr; 2018 ancount = ntohs(hp->ancount); 2019 qdcount = ntohs(hp->qdcount); 2020 bp = hostbuf; 2021 ep = hostbuf + sizeof hostbuf; 2022 cp = answer->buf + HFIXEDSZ; 2023 if (qdcount != 1) { 2024 RES_SET_H_ERRNO(res, NO_RECOVERY); 2025 return (NULL); 2026 } 2027 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 2028 if ((n < 0) || !(*name_ok)(bp)) { 2029 RES_SET_H_ERRNO(res, NO_RECOVERY); 2030 return (NULL); 2031 } 2032 cp += n + QFIXEDSZ; 2033 if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) { 2034 /* res_send() has already verified that the query name is the 2035 * same as the one we sent; this just gets the expanded name 2036 * (i.e., with the succeeding search-domain tacked on). 2037 */ 2038 n = strlen(bp) + 1; /* for the \0 */ 2039 if (n >= MAXHOSTNAMELEN) { 2040 RES_SET_H_ERRNO(res, NO_RECOVERY); 2041 return (NULL); 2042 } 2043 canonname = bp; 2044 bp += n; 2045 /* The qname can be abbreviated, but h_name is now absolute. */ 2046 qname = canonname; 2047 } 2048 haveanswer = 0; 2049 had_error = 0; 2050 while (ancount-- > 0 && cp < eom && !had_error) { 2051 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 2052 if ((n < 0) || !(*name_ok)(bp)) { 2053 had_error++; 2054 continue; 2055 } 2056 cp += n; /* name */ 2057 type = _getshort(cp); 2058 cp += INT16SZ; /* type */ 2059 class = _getshort(cp); 2060 cp += INT16SZ + INT32SZ; /* class, TTL */ 2061 n = _getshort(cp); 2062 cp += INT16SZ; /* len */ 2063 if (class != C_IN) { 2064 /* XXX - debug? syslog? */ 2065 cp += n; 2066 continue; /* XXX - had_error++ ? */ 2067 } 2068 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) && 2069 type == T_CNAME) { 2070 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); 2071 if ((n < 0) || !(*name_ok)(tbuf)) { 2072 had_error++; 2073 continue; 2074 } 2075 cp += n; 2076 /* Get canonical name. */ 2077 n = strlen(tbuf) + 1; /* for the \0 */ 2078 if (n > ep - bp || n >= MAXHOSTNAMELEN) { 2079 had_error++; 2080 continue; 2081 } 2082 strlcpy(bp, tbuf, ep - bp); 2083 canonname = bp; 2084 bp += n; 2085 continue; 2086 } 2087 if (qtype == T_ANY) { 2088 if (!(type == T_A || type == T_AAAA)) { 2089 cp += n; 2090 continue; 2091 } 2092 } else if (type != qtype) { 2093 #ifdef DEBUG 2094 if (type != T_KEY && type != T_SIG && 2095 type != T_DNAME && type != T_RRSIG) 2096 syslog(LOG_NOTICE|LOG_AUTH, 2097 "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"", 2098 qname, p_class(C_IN), p_type(qtype), 2099 p_type(type)); 2100 #endif 2101 cp += n; 2102 continue; /* XXX - had_error++ ? */ 2103 } 2104 switch (type) { 2105 case T_A: 2106 case T_AAAA: 2107 if (strcasecmp(canonname, bp) != 0) { 2108 #ifdef DEBUG 2109 syslog(LOG_NOTICE|LOG_AUTH, 2110 AskedForGot, canonname, bp); 2111 #endif 2112 cp += n; 2113 continue; /* XXX - had_error++ ? */ 2114 } 2115 if (type == T_A && n != INADDRSZ) { 2116 cp += n; 2117 continue; 2118 } 2119 if (type == T_AAAA && n != IN6ADDRSZ) { 2120 cp += n; 2121 continue; 2122 } 2123 #ifdef FILTER_V4MAPPED 2124 if (type == T_AAAA) { 2125 struct in6_addr in6; 2126 memcpy(&in6, cp, sizeof(in6)); 2127 if (IN6_IS_ADDR_V4MAPPED(&in6)) { 2128 cp += n; 2129 continue; 2130 } 2131 } 2132 #endif 2133 if (!haveanswer) { 2134 int nn; 2135 2136 canonname = bp; 2137 nn = strlen(bp) + 1; /* for the \0 */ 2138 bp += nn; 2139 } 2140 2141 /* don't overwrite pai */ 2142 ai = *pai; 2143 ai.ai_family = (type == T_A) ? AF_INET : AF_INET6; 2144 afd = find_afd(ai.ai_family); 2145 if (afd == NULL) { 2146 cp += n; 2147 continue; 2148 } 2149 cur->ai_next = get_ai(&ai, afd, (const char *)cp); 2150 if (cur->ai_next == NULL) 2151 had_error++; 2152 while (cur && cur->ai_next) 2153 cur = cur->ai_next; 2154 cp += n; 2155 break; 2156 default: 2157 abort(); 2158 } 2159 if (!had_error) 2160 haveanswer++; 2161 } 2162 if (haveanswer) { 2163 #if defined(RESOLVSORT) 2164 /* 2165 * We support only IPv4 address for backward 2166 * compatibility against gethostbyname(3). 2167 */ 2168 if (res->nsort && qtype == T_A) { 2169 if (addr4sort(&sentinel, res) < 0) { 2170 freeaddrinfo(sentinel.ai_next); 2171 RES_SET_H_ERRNO(res, NO_RECOVERY); 2172 return NULL; 2173 } 2174 } 2175 #endif /*RESOLVSORT*/ 2176 if (!canonname) 2177 (void)get_canonname(pai, sentinel.ai_next, qname); 2178 else 2179 (void)get_canonname(pai, sentinel.ai_next, canonname); 2180 RES_SET_H_ERRNO(res, NETDB_SUCCESS); 2181 return sentinel.ai_next; 2182 } 2183 2184 /* 2185 * We could have walked a CNAME chain, but the ultimate target 2186 * may not have what we looked for. 2187 */ 2188 RES_SET_H_ERRNO(res, ntohs(hp->ancount) > 0 ? NO_DATA : NO_RECOVERY); 2189 return NULL; 2190 } 2191 2192 #ifdef RESOLVSORT 2193 struct addr_ptr { 2194 struct addrinfo *ai; 2195 int aval; 2196 }; 2197 2198 static int 2199 addr4sort(struct addrinfo *sentinel, res_state res) 2200 { 2201 struct addrinfo *ai; 2202 struct addr_ptr *addrs, addr; 2203 struct sockaddr_in *sin; 2204 int naddrs, i, j; 2205 int needsort = 0; 2206 2207 if (!sentinel) 2208 return -1; 2209 naddrs = 0; 2210 for (ai = sentinel->ai_next; ai; ai = ai->ai_next) 2211 naddrs++; 2212 if (naddrs < 2) 2213 return 0; /* We don't need sorting. */ 2214 if ((addrs = malloc(sizeof(struct addr_ptr) * naddrs)) == NULL) 2215 return -1; 2216 i = 0; 2217 for (ai = sentinel->ai_next; ai; ai = ai->ai_next) { 2218 sin = (struct sockaddr_in *)ai->ai_addr; 2219 for (j = 0; (unsigned)j < res->nsort; j++) { 2220 if (res->sort_list[j].addr.s_addr == 2221 (sin->sin_addr.s_addr & res->sort_list[j].mask)) 2222 break; 2223 } 2224 addrs[i].ai = ai; 2225 addrs[i].aval = j; 2226 if (needsort == 0 && i > 0 && j < addrs[i - 1].aval) 2227 needsort = i; 2228 i++; 2229 } 2230 if (!needsort) { 2231 free(addrs); 2232 return 0; 2233 } 2234 2235 while (needsort < naddrs) { 2236 for (j = needsort - 1; j >= 0; j--) { 2237 if (addrs[j].aval > addrs[j+1].aval) { 2238 addr = addrs[j]; 2239 addrs[j] = addrs[j + 1]; 2240 addrs[j + 1] = addr; 2241 } else 2242 break; 2243 } 2244 needsort++; 2245 } 2246 2247 ai = sentinel; 2248 for (i = 0; i < naddrs; ++i) { 2249 ai->ai_next = addrs[i].ai; 2250 ai = ai->ai_next; 2251 } 2252 ai->ai_next = NULL; 2253 free(addrs); 2254 return 0; 2255 } 2256 #endif /*RESOLVSORT*/ 2257 2258 /*ARGSUSED*/ 2259 static int 2260 _dns_getaddrinfo(void *rv, void *cb_data, va_list ap) 2261 { 2262 struct addrinfo *ai, ai0; 2263 querybuf *buf, *buf2; 2264 const char *hostname; 2265 const struct addrinfo *pai; 2266 struct addrinfo sentinel, *cur; 2267 struct res_target q, q2; 2268 res_state res; 2269 2270 ai = NULL; 2271 2272 hostname = va_arg(ap, char *); 2273 pai = va_arg(ap, const struct addrinfo *); 2274 2275 memset(&q, 0, sizeof(q)); 2276 memset(&q2, 0, sizeof(q2)); 2277 memset(&sentinel, 0, sizeof(sentinel)); 2278 cur = &sentinel; 2279 2280 res = __res_state(); 2281 2282 buf = malloc(sizeof(*buf)); 2283 if (!buf) { 2284 RES_SET_H_ERRNO(res, NETDB_INTERNAL); 2285 return NS_NOTFOUND; 2286 } 2287 buf2 = malloc(sizeof(*buf2)); 2288 if (!buf2) { 2289 free(buf); 2290 RES_SET_H_ERRNO(res, NETDB_INTERNAL); 2291 return NS_NOTFOUND; 2292 } 2293 2294 if (pai->ai_family == AF_INET6 && 2295 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED) { 2296 ai0 = *pai; 2297 ai0.ai_family = AF_UNSPEC; 2298 pai = &ai0; 2299 } 2300 2301 switch (pai->ai_family) { 2302 case AF_UNSPEC: 2303 q.name = hostname; 2304 q.qclass = C_IN; 2305 q.qtype = T_A; 2306 q.answer = buf->buf; 2307 q.anslen = sizeof(buf->buf); 2308 q.next = &q2; 2309 q2.name = hostname; 2310 q2.qclass = C_IN; 2311 q2.qtype = T_AAAA; 2312 q2.answer = buf2->buf; 2313 q2.anslen = sizeof(buf2->buf); 2314 break; 2315 case AF_INET: 2316 q.name = hostname; 2317 q.qclass = C_IN; 2318 q.qtype = T_A; 2319 q.answer = buf->buf; 2320 q.anslen = sizeof(buf->buf); 2321 break; 2322 case AF_INET6: 2323 q.name = hostname; 2324 q.qclass = C_IN; 2325 q.qtype = T_AAAA; 2326 q.answer = buf->buf; 2327 q.anslen = sizeof(buf->buf); 2328 break; 2329 default: 2330 free(buf); 2331 free(buf2); 2332 return NS_UNAVAIL; 2333 } 2334 2335 if ((res->options & RES_INIT) == 0 && res_ninit(res) == -1) { 2336 RES_SET_H_ERRNO(res, NETDB_INTERNAL); 2337 free(buf); 2338 free(buf2); 2339 return NS_NOTFOUND; 2340 } 2341 2342 if (res_searchN(hostname, &q, res) < 0) { 2343 free(buf); 2344 free(buf2); 2345 switch (res->res_h_errno) { 2346 case NO_DATA: 2347 return (NS_ADDRFAMILY); 2348 case TRY_AGAIN: 2349 return (NS_TRYAGAIN); 2350 default: 2351 return (NS_NOTFOUND); 2352 } 2353 } 2354 /* prefer IPv6 */ 2355 if (q.next) { 2356 ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai, res); 2357 if (ai != NULL) { 2358 cur->ai_next = ai; 2359 while (cur && cur->ai_next) 2360 cur = cur->ai_next; 2361 } 2362 } 2363 if (ai == NULL || pai->ai_family != AF_UNSPEC || 2364 (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) != AI_V4MAPPED) { 2365 ai = getanswer(buf, q.n, q.name, q.qtype, pai, res); 2366 if (ai != NULL) 2367 cur->ai_next = ai; 2368 } 2369 free(buf); 2370 free(buf2); 2371 if (sentinel.ai_next == NULL) 2372 switch (res->res_h_errno) { 2373 case HOST_NOT_FOUND: 2374 return (NS_NOTFOUND); 2375 case NO_DATA: 2376 return (NS_ADDRFAMILY); 2377 case TRY_AGAIN: 2378 return (NS_TRYAGAIN); 2379 default: 2380 return (NS_UNAVAIL); 2381 } 2382 *((struct addrinfo **)rv) = sentinel.ai_next; 2383 return (NS_SUCCESS); 2384 } 2385 2386 static void 2387 _sethtent(FILE **hostf) 2388 { 2389 if (!*hostf) 2390 *hostf = fopen(_PATH_HOSTS, "re"); 2391 else 2392 rewind(*hostf); 2393 } 2394 2395 static void 2396 _endhtent(FILE **hostf) 2397 { 2398 if (*hostf) { 2399 (void) fclose(*hostf); 2400 *hostf = NULL; 2401 } 2402 } 2403 2404 static struct addrinfo * 2405 _gethtent(FILE **hostf, const char *name, const struct addrinfo *pai) 2406 { 2407 char *p; 2408 char *cp, *tname, *cname; 2409 struct addrinfo hints, *res0, *res; 2410 int error; 2411 const char *addr; 2412 char hostbuf[8*1024]; 2413 2414 if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "re"))) 2415 return (NULL); 2416 again: 2417 if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf))) 2418 return (NULL); 2419 if (*p == '#') 2420 goto again; 2421 cp = strpbrk(p, "#\n"); 2422 if (cp != NULL) 2423 *cp = '\0'; 2424 if (!(cp = strpbrk(p, " \t"))) 2425 goto again; 2426 *cp++ = '\0'; 2427 addr = p; 2428 cname = NULL; 2429 /* if this is not something we're looking for, skip it. */ 2430 while (cp && *cp) { 2431 if (*cp == ' ' || *cp == '\t') { 2432 cp++; 2433 continue; 2434 } 2435 tname = cp; 2436 if (cname == NULL) 2437 cname = cp; 2438 if ((cp = strpbrk(cp, " \t")) != NULL) 2439 *cp++ = '\0'; 2440 if (strcasecmp(name, tname) == 0) 2441 goto found; 2442 } 2443 goto again; 2444 2445 found: 2446 /* we should not glob socktype/protocol here */ 2447 memset(&hints, 0, sizeof(hints)); 2448 hints.ai_family = pai->ai_family; 2449 hints.ai_socktype = SOCK_DGRAM; 2450 hints.ai_protocol = 0; 2451 hints.ai_flags = AI_NUMERICHOST; 2452 if (pai->ai_family == AF_INET6 && 2453 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED) 2454 hints.ai_flags |= AI_V4MAPPED; 2455 error = getaddrinfo(addr, "0", &hints, &res0); 2456 if (error) 2457 goto again; 2458 #ifdef FILTER_V4MAPPED 2459 /* XXX should check all items in the chain */ 2460 if (res0->ai_family == AF_INET6 && 2461 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)res0->ai_addr)->sin6_addr)) { 2462 freeaddrinfo(res0); 2463 goto again; 2464 } 2465 #endif 2466 for (res = res0; res; res = res->ai_next) { 2467 /* cover it up */ 2468 res->ai_flags = pai->ai_flags; 2469 res->ai_socktype = pai->ai_socktype; 2470 res->ai_protocol = pai->ai_protocol; 2471 2472 if (pai->ai_flags & AI_CANONNAME) { 2473 if (get_canonname(pai, res, cname) != 0) { 2474 freeaddrinfo(res0); 2475 goto again; 2476 } 2477 } 2478 } 2479 return res0; 2480 } 2481 2482 static struct addrinfo * 2483 _getht(FILE **hostf, const char *name, const struct addrinfo *pai, 2484 struct addrinfo *cur) 2485 { 2486 struct addrinfo *p; 2487 2488 while ((p = _gethtent(hostf, name, pai)) != NULL) { 2489 cur->ai_next = p; 2490 while (cur && cur->ai_next) 2491 cur = cur->ai_next; 2492 } 2493 return (cur); 2494 } 2495 2496 /*ARGSUSED*/ 2497 static int 2498 _files_getaddrinfo(void *rv, void *cb_data, va_list ap) 2499 { 2500 const char *name; 2501 const struct addrinfo *pai; 2502 struct addrinfo sentinel, *cur; 2503 FILE *hostf = NULL; 2504 2505 name = va_arg(ap, char *); 2506 pai = va_arg(ap, struct addrinfo *); 2507 2508 memset(&sentinel, 0, sizeof(sentinel)); 2509 cur = &sentinel; 2510 2511 _sethtent(&hostf); 2512 if (pai->ai_family == AF_INET6 && 2513 (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) == AI_V4MAPPED) { 2514 struct addrinfo ai0 = *pai; 2515 2516 ai0.ai_flags &= ~AI_V4MAPPED; 2517 cur = _getht(&hostf, name, &ai0, cur); 2518 if (sentinel.ai_next == NULL) { 2519 _sethtent(&hostf); 2520 ai0.ai_flags |= AI_V4MAPPED; 2521 cur = _getht(&hostf, name, &ai0, cur); 2522 } 2523 } else 2524 cur = _getht(&hostf, name, pai, cur); 2525 _endhtent(&hostf); 2526 2527 *((struct addrinfo **)rv) = sentinel.ai_next; 2528 if (sentinel.ai_next == NULL) 2529 return NS_NOTFOUND; 2530 return NS_SUCCESS; 2531 } 2532 2533 #ifdef YP 2534 /*ARGSUSED*/ 2535 static struct addrinfo * 2536 _yphostent(char *line, const struct addrinfo *pai) 2537 { 2538 struct addrinfo sentinel, *cur; 2539 struct addrinfo hints, *res, *res0; 2540 int error; 2541 char *p = line; 2542 const char *addr, *canonname; 2543 char *nextline; 2544 char *cp; 2545 2546 addr = canonname = NULL; 2547 2548 memset(&sentinel, 0, sizeof(sentinel)); 2549 cur = &sentinel; 2550 2551 nextline: 2552 /* terminate line */ 2553 cp = strchr(p, '\n'); 2554 if (cp) { 2555 *cp++ = '\0'; 2556 nextline = cp; 2557 } else 2558 nextline = NULL; 2559 2560 cp = strpbrk(p, " \t"); 2561 if (cp == NULL) { 2562 if (canonname == NULL) 2563 return (NULL); 2564 else 2565 goto done; 2566 } 2567 *cp++ = '\0'; 2568 2569 addr = p; 2570 2571 while (cp && *cp) { 2572 if (*cp == ' ' || *cp == '\t') { 2573 cp++; 2574 continue; 2575 } 2576 if (!canonname) 2577 canonname = cp; 2578 if ((cp = strpbrk(cp, " \t")) != NULL) 2579 *cp++ = '\0'; 2580 } 2581 2582 hints = *pai; 2583 hints.ai_flags = AI_NUMERICHOST; 2584 if (pai->ai_family == AF_INET6 && 2585 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED) 2586 hints.ai_flags |= AI_V4MAPPED; 2587 error = getaddrinfo(addr, NULL, &hints, &res0); 2588 if (error == 0) { 2589 for (res = res0; res; res = res->ai_next) { 2590 /* cover it up */ 2591 res->ai_flags = pai->ai_flags; 2592 2593 if (pai->ai_flags & AI_CANONNAME) 2594 (void)get_canonname(pai, res, canonname); 2595 } 2596 } else 2597 res0 = NULL; 2598 if (res0) { 2599 cur->ai_next = res0; 2600 while (cur && cur->ai_next) 2601 cur = cur->ai_next; 2602 } 2603 2604 if (nextline) { 2605 p = nextline; 2606 goto nextline; 2607 } 2608 2609 done: 2610 return sentinel.ai_next; 2611 } 2612 2613 /*ARGSUSED*/ 2614 static int 2615 _yp_getaddrinfo(void *rv, void *cb_data, va_list ap) 2616 { 2617 struct addrinfo sentinel, *cur; 2618 struct addrinfo *ai = NULL; 2619 char *ypbuf; 2620 int ypbuflen, r; 2621 const char *name; 2622 const struct addrinfo *pai; 2623 char *ypdomain; 2624 2625 if (_yp_check(&ypdomain) == 0) 2626 return NS_UNAVAIL; 2627 2628 name = va_arg(ap, char *); 2629 pai = va_arg(ap, const struct addrinfo *); 2630 2631 memset(&sentinel, 0, sizeof(sentinel)); 2632 cur = &sentinel; 2633 2634 /* ipnodes.byname can hold both IPv4/v6 */ 2635 r = yp_match(ypdomain, "ipnodes.byname", name, 2636 (int)strlen(name), &ypbuf, &ypbuflen); 2637 if (r == 0) { 2638 ai = _yphostent(ypbuf, pai); 2639 if (ai) { 2640 cur->ai_next = ai; 2641 while (cur && cur->ai_next) 2642 cur = cur->ai_next; 2643 } 2644 free(ypbuf); 2645 } 2646 2647 if (ai != NULL) { 2648 struct sockaddr_in6 *sin6; 2649 2650 switch (ai->ai_family) { 2651 case AF_INET: 2652 goto done; 2653 case AF_INET6: 2654 sin6 = (struct sockaddr_in6 *)ai->ai_addr; 2655 if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 2656 goto done; 2657 break; 2658 } 2659 } 2660 2661 /* hosts.byname is only for IPv4 (Solaris8) */ 2662 if (pai->ai_family == AF_UNSPEC || pai->ai_family == AF_INET || 2663 ((pai->ai_family == AF_INET6 && 2664 (pai->ai_flags & AI_V4MAPPED) == AI_V4MAPPED) && 2665 (ai == NULL || (pai->ai_flags & AI_ALL) == AI_ALL))) { 2666 r = yp_match(ypdomain, "hosts.byname", name, 2667 (int)strlen(name), &ypbuf, &ypbuflen); 2668 if (r == 0) { 2669 struct addrinfo ai4; 2670 2671 ai4 = *pai; 2672 if (pai->ai_family == AF_UNSPEC) 2673 ai4.ai_family = AF_INET; 2674 ai = _yphostent(ypbuf, &ai4); 2675 if (ai) { 2676 cur->ai_next = ai; 2677 while (cur && cur->ai_next) 2678 cur = cur->ai_next; 2679 } 2680 free(ypbuf); 2681 } 2682 } 2683 2684 done: 2685 if (sentinel.ai_next == NULL) { 2686 RES_SET_H_ERRNO(__res_state(), HOST_NOT_FOUND); 2687 return NS_NOTFOUND; 2688 } 2689 *((struct addrinfo **)rv) = sentinel.ai_next; 2690 return NS_SUCCESS; 2691 } 2692 #endif 2693 2694 /* resolver logic */ 2695 2696 /* 2697 * Formulate a normal query, send, and await answer. 2698 * Returned answer is placed in supplied buffer "answer". 2699 * Perform preliminary check of answer, returning success only 2700 * if no error is indicated and the answer count is nonzero. 2701 * Return the size of the response on success, -1 on error. 2702 * Error number is left in h_errno. 2703 * 2704 * Caller must parse answer and determine whether it answers the question. 2705 */ 2706 static int 2707 res_queryN(const char *name, struct res_target *target, res_state res) 2708 { 2709 u_char *buf; 2710 HEADER *hp; 2711 int n; 2712 u_int oflags; 2713 struct res_target *t; 2714 u_int rcode; 2715 int ancount; 2716 2717 /* 2718 * Extend rcode values in the scope of this function. The DNS header 2719 * rcode we use in this function (hp->rcode) is limited by 4 bits, so 2720 * anything starting from 16 is safe wrt aliasing. However, nameser.h 2721 * already has extended enum __ns_rcode, so for future safety let's use 2722 * even larger values. 2723 */ 2724 #define RCODE_UNREACH 32 2725 #define RCODE_TIMEDOUT 33 2726 rcode = NOERROR; 2727 ancount = 0; 2728 2729 buf = malloc(MAXPACKET); 2730 if (!buf) { 2731 RES_SET_H_ERRNO(res, NETDB_INTERNAL); 2732 return -1; 2733 } 2734 2735 for (t = target; t; t = t->next) { 2736 int class, type; 2737 u_char *answer; 2738 int anslen; 2739 2740 hp = (HEADER *)(void *)t->answer; 2741 2742 /* make it easier... */ 2743 class = t->qclass; 2744 type = t->qtype; 2745 answer = t->answer; 2746 anslen = t->anslen; 2747 2748 oflags = res->_flags; 2749 2750 again: 2751 hp->rcode = NOERROR; /* default */ 2752 2753 #ifdef DEBUG 2754 if (res->options & RES_DEBUG) 2755 printf(";; res_query(%s, %d, %d)\n", name, class, type); 2756 #endif 2757 2758 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL, 2759 buf, MAXPACKET); 2760 if (n > 0 && (res->_flags & RES_F_EDNS0ERR) == 0 && 2761 (res->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0U) 2762 n = res_nopt(res, n, buf, MAXPACKET, anslen); 2763 if (n <= 0) { 2764 #ifdef DEBUG 2765 if (res->options & RES_DEBUG) 2766 printf(";; res_query: mkquery failed\n"); 2767 #endif 2768 free(buf); 2769 RES_SET_H_ERRNO(res, NO_RECOVERY); 2770 return (n); 2771 } 2772 n = res_nsend(res, buf, n, answer, anslen); 2773 if (n < 0) { 2774 /* 2775 * if the query choked with EDNS0, retry 2776 * without EDNS0 2777 */ 2778 if ((res->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) 2779 != 0U && 2780 ((oflags ^ res->_flags) & RES_F_EDNS0ERR) != 0) { 2781 res->_flags |= RES_F_EDNS0ERR; 2782 if (res->options & RES_DEBUG) 2783 printf(";; res_nquery: retry without EDNS0\n"); 2784 goto again; 2785 } 2786 /* 2787 * Historically if a DNS server replied with ICMP port 2788 * unreach res_nsend() would signal that with 2789 * ECONNREFUSED and the upper layers would convert that 2790 * into TRY_AGAIN. See 3a0b3b673936b and deeper. 2791 * Also, res_nsend() may set errno to ECONNREFUSED due 2792 * to internal failures. This may not be intentional, 2793 * but we also treat that as soft failures. 2794 * 2795 * A more practical case is when a DNS server(s) were 2796 * queried and didn't respond anything, which usually 2797 * indicates a soft network failure. 2798 */ 2799 switch (errno) { 2800 case ECONNREFUSED: 2801 rcode = RCODE_UNREACH; 2802 break; 2803 case ETIMEDOUT: 2804 rcode = RCODE_TIMEDOUT; 2805 break; 2806 default: 2807 rcode = hp->rcode; 2808 } 2809 #ifdef DEBUG 2810 if (res->options & RES_DEBUG) 2811 printf(";; res_query: send error\n"); 2812 #endif 2813 continue; 2814 } 2815 2816 if (n > anslen) 2817 hp->rcode = FORMERR; /* XXX not very informative */ 2818 if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) { 2819 rcode = hp->rcode; /* record most recent error */ 2820 #ifdef DEBUG 2821 if (res->options & RES_DEBUG) 2822 printf(";; rcode = %u, ancount=%u\n", hp->rcode, 2823 ntohs(hp->ancount)); 2824 #endif 2825 continue; 2826 } 2827 2828 ancount += ntohs(hp->ancount); 2829 2830 t->n = n; 2831 } 2832 2833 free(buf); 2834 2835 if (ancount == 0) { 2836 switch (rcode) { 2837 case NXDOMAIN: 2838 RES_SET_H_ERRNO(res, HOST_NOT_FOUND); 2839 break; 2840 case RCODE_UNREACH: 2841 case RCODE_TIMEDOUT: 2842 case SERVFAIL: 2843 RES_SET_H_ERRNO(res, TRY_AGAIN); 2844 break; 2845 case NOERROR: 2846 RES_SET_H_ERRNO(res, NO_DATA); 2847 break; 2848 case FORMERR: 2849 case NOTIMP: 2850 case REFUSED: 2851 default: 2852 RES_SET_H_ERRNO(res, NO_RECOVERY); 2853 break; 2854 } 2855 return (-1); 2856 } 2857 return (ancount); 2858 } 2859 2860 /* 2861 * Formulate a normal query, send, and retrieve answer in supplied buffer. 2862 * Return the size of the response on success, -1 on error. 2863 * If enabled, implement search rules until answer or unrecoverable failure 2864 * is detected. Error code, if any, is left in h_errno. 2865 */ 2866 static int 2867 res_searchN(const char *name, struct res_target *target, res_state res) 2868 { 2869 const char *cp, * const *domain; 2870 HEADER *hp = (HEADER *)(void *)target->answer; /*XXX*/ 2871 u_int dots; 2872 int trailing_dot, ret, saved_herrno; 2873 int got_nodata = 0, got_servfail = 0, root_on_list = 0; 2874 int tried_as_is = 0; 2875 int searched = 0; 2876 char abuf[MAXDNAME]; 2877 2878 errno = 0; 2879 RES_SET_H_ERRNO(res, HOST_NOT_FOUND); /* default, if we never query */ 2880 dots = 0; 2881 for (cp = name; *cp; cp++) 2882 dots += (*cp == '.'); 2883 trailing_dot = 0; 2884 if (cp > name && *--cp == '.') 2885 trailing_dot++; 2886 2887 /* 2888 * if there aren't any dots, it could be a user-level alias 2889 */ 2890 if (!dots && 2891 (cp = res_hostalias(res, name, abuf, sizeof(abuf))) != NULL) 2892 return (res_queryN(cp, target, res)); 2893 2894 /* 2895 * If there are enough dots in the name, let's just give it a 2896 * try 'as is'. The threshold can be set with the "ndots" option. 2897 * Also, query 'as is', if there is a trailing dot in the name. 2898 */ 2899 saved_herrno = -1; 2900 if (dots >= res->ndots || trailing_dot) { 2901 ret = res_querydomainN(name, NULL, target, res); 2902 if (ret > 0 || trailing_dot) 2903 return (ret); 2904 switch (res->res_h_errno) { 2905 case NO_DATA: 2906 case HOST_NOT_FOUND: 2907 break; 2908 case TRY_AGAIN: 2909 if (hp->rcode == SERVFAIL) 2910 break; 2911 /* FALLTHROUGH */ 2912 default: 2913 return (-1); 2914 } 2915 saved_herrno = res->res_h_errno; 2916 tried_as_is++; 2917 } 2918 2919 /* 2920 * We do at least one level of search if 2921 * - there is no dot and RES_DEFNAME is set, or 2922 * - there is at least one dot, there is no trailing dot, 2923 * and RES_DNSRCH is set. 2924 */ 2925 if ((!dots && (res->options & RES_DEFNAMES)) || 2926 (dots && !trailing_dot && (res->options & RES_DNSRCH))) { 2927 int done = 0; 2928 2929 for (domain = (const char * const *)res->dnsrch; 2930 *domain && !done; 2931 domain++) { 2932 searched = 1; 2933 2934 if (domain[0][0] == '\0' || 2935 (domain[0][0] == '.' && domain[0][1] == '\0')) 2936 root_on_list++; 2937 2938 if (root_on_list && tried_as_is) 2939 continue; 2940 2941 ret = res_querydomainN(name, *domain, target, res); 2942 if (ret > 0) 2943 return (ret); 2944 /* 2945 * If no server present, give up. 2946 * If name isn't found in this domain, 2947 * keep trying higher domains in the search list 2948 * (if that's enabled). 2949 * On a NO_DATA error, keep trying, otherwise 2950 * a wildcard entry of another type could keep us 2951 * from finding this entry higher in the domain. 2952 * If we get some other error (negative answer or 2953 * server failure), then stop searching up, 2954 * but try the input name below in case it's 2955 * fully-qualified. 2956 */ 2957 switch (res->res_h_errno) { 2958 case NO_DATA: 2959 got_nodata++; 2960 /* FALLTHROUGH */ 2961 case HOST_NOT_FOUND: 2962 /* keep trying */ 2963 break; 2964 case TRY_AGAIN: 2965 if (hp->rcode == SERVFAIL) { 2966 got_servfail++; 2967 /* try next search element, if any */ 2968 break; 2969 } 2970 /* FALLTHROUGH */ 2971 default: 2972 /* anything else implies that we're done */ 2973 done++; 2974 } 2975 /* 2976 * if we got here for some reason other than DNSRCH, 2977 * we only wanted one iteration of the loop, so stop. 2978 */ 2979 if (!(res->options & RES_DNSRCH)) 2980 done++; 2981 } 2982 } 2983 2984 switch (res->res_h_errno) { 2985 case NO_DATA: 2986 case HOST_NOT_FOUND: 2987 break; 2988 case TRY_AGAIN: 2989 if (hp->rcode == SERVFAIL) 2990 break; 2991 /* FALLTHROUGH */ 2992 default: 2993 goto giveup; 2994 } 2995 2996 /* 2997 * If the query has not already been tried as is then try it 2998 * unless RES_NOTLDQUERY is set and there were no dots. 2999 */ 3000 if ((dots || !searched || !(res->options & RES_NOTLDQUERY)) && 3001 !(tried_as_is || root_on_list)) { 3002 ret = res_querydomainN(name, NULL, target, res); 3003 if (ret > 0) 3004 return (ret); 3005 } 3006 3007 /* 3008 * if we got here, we didn't satisfy the search. 3009 * if we did an initial full query, return that query's h_errno 3010 * (note that we wouldn't be here if that query had succeeded). 3011 * else if we ever got a nodata, send that back as the reason. 3012 * else send back meaningless h_errno, that being the one from 3013 * the last DNSRCH we did. 3014 */ 3015 giveup: 3016 if (saved_herrno != -1) 3017 RES_SET_H_ERRNO(res, saved_herrno); 3018 else if (got_nodata) 3019 RES_SET_H_ERRNO(res, NO_DATA); 3020 else if (got_servfail) 3021 RES_SET_H_ERRNO(res, TRY_AGAIN); 3022 return (-1); 3023 } 3024 3025 /* 3026 * Perform a call on res_query on the concatenation of name and domain, 3027 * removing a trailing dot from name if domain is NULL. 3028 */ 3029 static int 3030 res_querydomainN(const char *name, const char *domain, 3031 struct res_target *target, res_state res) 3032 { 3033 char nbuf[MAXDNAME]; 3034 const char *longname = nbuf; 3035 size_t n, d; 3036 3037 #ifdef DEBUG 3038 if (res->options & RES_DEBUG) 3039 printf(";; res_querydomain(%s, %s)\n", 3040 name, domain?domain:"<Nil>"); 3041 #endif 3042 if (domain == NULL) { 3043 /* 3044 * Check for trailing '.'; 3045 * copy without '.' if present. 3046 */ 3047 n = strlen(name); 3048 if (n >= MAXDNAME) { 3049 RES_SET_H_ERRNO(res, NO_RECOVERY); 3050 return (-1); 3051 } 3052 if (n > 0 && name[--n] == '.') { 3053 strncpy(nbuf, name, n); 3054 nbuf[n] = '\0'; 3055 } else 3056 longname = name; 3057 } else { 3058 n = strlen(name); 3059 d = strlen(domain); 3060 if (n + d + 1 >= MAXDNAME) { 3061 RES_SET_H_ERRNO(res, NO_RECOVERY); 3062 return (-1); 3063 } 3064 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain); 3065 } 3066 return (res_queryN(longname, target, res)); 3067 } 3068