getaddrinfo.c revision 233770
1/* $KAME: getaddrinfo.c,v 1.15 2000/07/09 04:37:24 itojun Exp $ */ 2 3/* 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32/* 33 * "#ifdef FAITH" part is local hack for supporting IPv4-v6 translator. 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 - SEGV on freeaddrinfo(NULL) 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 $GAI. The code does not. 54 */ 55 56#include <sys/cdefs.h> 57__FBSDID("$FreeBSD: head/lib/libc/net/getaddrinfo.c 233770 2012-04-02 07:42:17Z delphij $"); 58 59#include "namespace.h" 60#include <sys/types.h> 61#include <sys/param.h> 62#include <sys/socket.h> 63#include <net/if.h> 64#include <netinet/in.h> 65#include <sys/queue.h> 66#ifdef INET6 67#include <net/if_var.h> 68#include <sys/sysctl.h> 69#include <sys/ioctl.h> 70#include <netinet6/in6_var.h> /* XXX */ 71#endif 72#include <arpa/inet.h> 73#include <arpa/nameser.h> 74#include <rpc/rpc.h> 75#include <rpcsvc/yp_prot.h> 76#include <rpcsvc/ypclnt.h> 77#include <netdb.h> 78#include <resolv.h> 79#include <string.h> 80#include <stdlib.h> 81#include <stddef.h> 82#include <ctype.h> 83#include <unistd.h> 84#include <stdio.h> 85#include <errno.h> 86 87#include "res_config.h" 88 89#ifdef DEBUG 90#include <syslog.h> 91#endif 92 93#include <stdarg.h> 94#include <nsswitch.h> 95#include "un-namespace.h" 96#include "libc_private.h" 97#ifdef NS_CACHING 98#include "nscache.h" 99#endif 100 101#if defined(__KAME__) && defined(INET6) 102# define FAITH 103#endif 104 105#define ANY 0 106#define YES 1 107#define NO 0 108 109static const char in_addrany[] = { 0, 0, 0, 0 }; 110static const char in_loopback[] = { 127, 0, 0, 1 }; 111#ifdef INET6 112static const char in6_addrany[] = { 113 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 114}; 115static const char in6_loopback[] = { 116 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 117}; 118#endif 119 120struct policyqueue { 121 TAILQ_ENTRY(policyqueue) pc_entry; 122#ifdef INET6 123 struct in6_addrpolicy pc_policy; 124#endif 125}; 126TAILQ_HEAD(policyhead, policyqueue); 127 128static const struct afd { 129 int a_af; 130 int a_addrlen; 131 socklen_t a_socklen; 132 int a_off; 133 const char *a_addrany; 134 const char *a_loopback; 135 int a_scoped; 136} afdl [] = { 137#ifdef INET6 138#define N_INET6 0 139 {PF_INET6, sizeof(struct in6_addr), 140 sizeof(struct sockaddr_in6), 141 offsetof(struct sockaddr_in6, sin6_addr), 142 in6_addrany, in6_loopback, 1}, 143#define N_INET 1 144#else 145#define N_INET 0 146#endif 147 {PF_INET, sizeof(struct in_addr), 148 sizeof(struct sockaddr_in), 149 offsetof(struct sockaddr_in, sin_addr), 150 in_addrany, in_loopback, 0}, 151 {0, 0, 0, 0, NULL, NULL, 0}, 152}; 153 154struct explore { 155 int e_af; 156 int e_socktype; 157 int e_protocol; 158 const char *e_protostr; 159 int e_wild; 160#define WILD_AF(ex) ((ex)->e_wild & 0x01) 161#define WILD_SOCKTYPE(ex) ((ex)->e_wild & 0x02) 162#define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04) 163}; 164 165static const struct explore explore[] = { 166#if 0 167 { PF_LOCAL, ANY, ANY, NULL, 0x01 }, 168#endif 169#ifdef INET6 170 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, 171 { PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, 172 { PF_INET6, SOCK_STREAM, IPPROTO_SCTP, "sctp", 0x03 }, 173 { PF_INET6, SOCK_SEQPACKET, IPPROTO_SCTP, "sctp", 0x07 }, 174 { PF_INET6, SOCK_RAW, ANY, NULL, 0x05 }, 175#endif 176 { PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, 177 { PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, 178 { PF_INET, SOCK_STREAM, IPPROTO_SCTP, "sctp", 0x03 }, 179 { PF_INET, SOCK_SEQPACKET, IPPROTO_SCTP, "sctp", 0x07 }, 180 { PF_INET, SOCK_RAW, ANY, NULL, 0x05 }, 181 { -1, 0, 0, NULL, 0 }, 182}; 183 184#ifdef INET6 185#define PTON_MAX 16 186#else 187#define PTON_MAX 4 188#endif 189 190#define AIO_SRCFLAG_DEPRECATED 0x1 191 192struct ai_order { 193 union { 194 struct sockaddr_storage aiou_ss; 195 struct sockaddr aiou_sa; 196 } aio_src_un; 197#define aio_srcsa aio_src_un.aiou_sa 198 u_int32_t aio_srcflag; 199 int aio_srcscope; 200 int aio_dstscope; 201 struct policyqueue *aio_srcpolicy; 202 struct policyqueue *aio_dstpolicy; 203 struct addrinfo *aio_ai; 204 int aio_matchlen; 205}; 206 207static const ns_src default_dns_files[] = { 208 { NSSRC_FILES, NS_SUCCESS }, 209 { NSSRC_DNS, NS_SUCCESS }, 210 { 0 } 211}; 212 213struct res_target { 214 struct res_target *next; 215 const char *name; /* domain name */ 216 int qclass, qtype; /* class and type of query */ 217 u_char *answer; /* buffer to put answer */ 218 int anslen; /* size of answer buffer */ 219 int n; /* result length */ 220}; 221 222#define MAXPACKET (64*1024) 223 224typedef union { 225 HEADER hdr; 226 u_char buf[MAXPACKET]; 227} querybuf; 228 229static int str2number(const char *, int *); 230static int explore_copy(const struct addrinfo *, const struct addrinfo *, 231 struct addrinfo **); 232static int explore_null(const struct addrinfo *, 233 const char *, struct addrinfo **); 234static int explore_numeric(const struct addrinfo *, const char *, 235 const char *, struct addrinfo **, const char *); 236static int explore_numeric_scope(const struct addrinfo *, const char *, 237 const char *, struct addrinfo **); 238static int get_canonname(const struct addrinfo *, 239 struct addrinfo *, const char *); 240static struct addrinfo *get_ai(const struct addrinfo *, 241 const struct afd *, const char *); 242static struct addrinfo *copy_ai(const struct addrinfo *); 243static int get_portmatch(const struct addrinfo *, const char *); 244static int get_port(struct addrinfo *, const char *, int); 245static const struct afd *find_afd(int); 246static int addrconfig(struct addrinfo *); 247static void set_source(struct ai_order *, struct policyhead *); 248static int comp_dst(const void *, const void *); 249#ifdef INET6 250static int ip6_str2scopeid(char *, struct sockaddr_in6 *, u_int32_t *); 251#endif 252static int gai_addr2scopetype(struct sockaddr *); 253 254static int explore_fqdn(const struct addrinfo *, const char *, 255 const char *, struct addrinfo **); 256 257static int reorder(struct addrinfo *); 258static int get_addrselectpolicy(struct policyhead *); 259static void free_addrselectpolicy(struct policyhead *); 260static struct policyqueue *match_addrselectpolicy(struct sockaddr *, 261 struct policyhead *); 262static int matchlen(struct sockaddr *, struct sockaddr *); 263 264static struct addrinfo *getanswer(const querybuf *, int, const char *, int, 265 const struct addrinfo *, res_state); 266#if defined(RESOLVSORT) 267static int addr4sort(struct addrinfo *, res_state); 268#endif 269static int _dns_getaddrinfo(void *, void *, va_list); 270static void _sethtent(FILE **); 271static void _endhtent(FILE **); 272static struct addrinfo *_gethtent(FILE **, const char *, 273 const struct addrinfo *); 274static int _files_getaddrinfo(void *, void *, va_list); 275#ifdef YP 276static struct addrinfo *_yphostent(char *, const struct addrinfo *); 277static int _yp_getaddrinfo(void *, void *, va_list); 278#endif 279#ifdef NS_CACHING 280static int addrinfo_id_func(char *, size_t *, va_list, void *); 281static int addrinfo_marshal_func(char *, size_t *, void *, va_list, void *); 282static int addrinfo_unmarshal_func(char *, size_t, void *, va_list, void *); 283#endif 284 285static int res_queryN(const char *, struct res_target *, res_state); 286static int res_searchN(const char *, struct res_target *, res_state); 287static int res_querydomainN(const char *, const char *, 288 struct res_target *, res_state); 289 290/* XXX macros that make external reference is BAD. */ 291 292#define GET_AI(ai, afd, addr) \ 293do { \ 294 /* external reference: pai, error, and label free */ \ 295 (ai) = get_ai(pai, (afd), (addr)); \ 296 if ((ai) == NULL) { \ 297 error = EAI_MEMORY; \ 298 goto free; \ 299 } \ 300} while (/*CONSTCOND*/0) 301 302#define GET_PORT(ai, serv) \ 303do { \ 304 /* external reference: error and label free */ \ 305 error = get_port((ai), (serv), 0); \ 306 if (error != 0) \ 307 goto free; \ 308} while (/*CONSTCOND*/0) 309 310#define GET_CANONNAME(ai, str) \ 311do { \ 312 /* external reference: pai, error and label free */ \ 313 error = get_canonname(pai, (ai), (str)); \ 314 if (error != 0) \ 315 goto free; \ 316} while (/*CONSTCOND*/0) 317 318#define ERR(err) \ 319do { \ 320 /* external reference: error, and label bad */ \ 321 error = (err); \ 322 goto bad; \ 323 /*NOTREACHED*/ \ 324} while (/*CONSTCOND*/0) 325 326#define MATCH_FAMILY(x, y, w) \ 327 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || (y) == PF_UNSPEC))) 328#define MATCH(x, y, w) \ 329 ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY))) 330 331void 332freeaddrinfo(struct addrinfo *ai) 333{ 334 struct addrinfo *next; 335 336 do { 337 next = ai->ai_next; 338 if (ai->ai_canonname) 339 free(ai->ai_canonname); 340 /* no need to free(ai->ai_addr) */ 341 free(ai); 342 ai = next; 343 } while (ai); 344} 345 346static int 347str2number(const char *p, int *portp) 348{ 349 char *ep; 350 unsigned long v; 351 352 if (*p == '\0') 353 return -1; 354 ep = NULL; 355 errno = 0; 356 v = strtoul(p, &ep, 10); 357 if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX) { 358 *portp = v; 359 return 0; 360 } else 361 return -1; 362} 363 364int 365getaddrinfo(const char *hostname, const char *servname, 366 const struct addrinfo *hints, struct addrinfo **res) 367{ 368 struct addrinfo sentinel; 369 struct addrinfo *cur; 370 int error = 0; 371 struct addrinfo ai, ai0, *afai; 372 struct addrinfo *pai; 373 const struct afd *afd; 374 const struct explore *ex; 375 struct addrinfo *afailist[sizeof(afdl)/sizeof(afdl[0])]; 376 struct addrinfo *afai_unspec; 377 int found; 378 int numeric = 0; 379 380 /* ensure we return NULL on errors */ 381 *res = NULL; 382 383 memset(&ai, 0, sizeof(ai)); 384 385 memset(afailist, 0, sizeof(afailist)); 386 afai_unspec = NULL; 387 388 memset(&sentinel, 0, sizeof(sentinel)); 389 cur = &sentinel; 390 pai = &ai; 391 pai->ai_flags = 0; 392 pai->ai_family = PF_UNSPEC; 393 pai->ai_socktype = ANY; 394 pai->ai_protocol = ANY; 395 pai->ai_addrlen = 0; 396 pai->ai_canonname = NULL; 397 pai->ai_addr = NULL; 398 pai->ai_next = NULL; 399 400 if (hostname == NULL && servname == NULL) 401 return EAI_NONAME; 402 if (hints) { 403 /* error check for hints */ 404 if (hints->ai_addrlen || hints->ai_canonname || 405 hints->ai_addr || hints->ai_next) 406 ERR(EAI_BADHINTS); /* xxx */ 407 if (hints->ai_flags & ~AI_MASK) 408 ERR(EAI_BADFLAGS); 409 switch (hints->ai_family) { 410 case PF_UNSPEC: 411 case PF_INET: 412#ifdef INET6 413 case PF_INET6: 414#endif 415 break; 416 default: 417 ERR(EAI_FAMILY); 418 } 419 memcpy(pai, hints, sizeof(*pai)); 420 421 /* 422 * if both socktype/protocol are specified, check if they 423 * are meaningful combination. 424 */ 425 if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) { 426 for (ex = explore; ex->e_af >= 0; ex++) { 427 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, 428 WILD_AF(ex))) 429 continue; 430 if (!MATCH(pai->ai_socktype, ex->e_socktype, 431 WILD_SOCKTYPE(ex))) 432 continue; 433 if (!MATCH(pai->ai_protocol, ex->e_protocol, 434 WILD_PROTOCOL(ex))) 435 continue; 436 437 /* matched */ 438 break; 439 } 440 441 if (ex->e_af < 0) 442 ERR(EAI_BADHINTS); 443 } 444 } 445 446 /* 447 * check for special cases. (1) numeric servname is disallowed if 448 * socktype/protocol are left unspecified. (2) servname is disallowed 449 * for raw and other inet{,6} sockets. 450 */ 451 if (MATCH_FAMILY(pai->ai_family, PF_INET, 1) 452#ifdef PF_INET6 453 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1) 454#endif 455 ) { 456 ai0 = *pai; /* backup *pai */ 457 458 if (pai->ai_family == PF_UNSPEC) { 459#ifdef PF_INET6 460 pai->ai_family = PF_INET6; 461#else 462 pai->ai_family = PF_INET; 463#endif 464 } 465 error = get_portmatch(pai, servname); 466 if (error) 467 ERR(error); 468 469 *pai = ai0; 470 } 471 472 ai0 = *pai; 473 474 /* 475 * NULL hostname, or numeric hostname. 476 * If numeric representation of AF1 can be interpreted as FQDN 477 * representation of AF2, we need to think again about the code below. 478 */ 479 found = 0; 480 for (afd = afdl; afd->a_af; afd++) { 481 *pai = ai0; 482 483 if (!MATCH_FAMILY(pai->ai_family, afd->a_af, 1)) 484 continue; 485 486 if (pai->ai_family == PF_UNSPEC) 487 pai->ai_family = afd->a_af; 488 489 if (hostname == NULL) { 490 error = explore_null(pai, servname, 491 &afailist[afd - afdl]); 492 493 /* 494 * Errors from explore_null should be unexpected and 495 * be caught to avoid returning an incomplete result. 496 */ 497 if (error != 0) 498 goto bad; 499 } else { 500 error = explore_numeric_scope(pai, hostname, servname, 501 &afailist[afd - afdl]); 502 503 /* 504 * explore_numeric_scope returns an error for address 505 * families that do not match that of hostname. 506 * Thus we should not catch the error at this moment. 507 */ 508 } 509 510 if (!error && afailist[afd - afdl]) 511 found++; 512 } 513 if (found) { 514 numeric = 1; 515 goto globcopy; 516 } 517 518 if (hostname == NULL) 519 ERR(EAI_NONAME); /* used to be EAI_NODATA */ 520 if (pai->ai_flags & AI_NUMERICHOST) 521 ERR(EAI_NONAME); 522 523 if ((pai->ai_flags & AI_ADDRCONFIG) != 0 && !addrconfig(&ai0)) 524 ERR(EAI_FAIL); 525 526 /* 527 * hostname as alphabetical name. 528 */ 529 *pai = ai0; 530 error = explore_fqdn(pai, hostname, servname, &afai_unspec); 531 532globcopy: 533 for (ex = explore; ex->e_af >= 0; ex++) { 534 *pai = ai0; 535 536 if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex))) 537 continue; 538 if (!MATCH(pai->ai_socktype, ex->e_socktype, 539 WILD_SOCKTYPE(ex))) 540 continue; 541 if (!MATCH(pai->ai_protocol, ex->e_protocol, 542 WILD_PROTOCOL(ex))) 543 continue; 544 545 if (pai->ai_family == PF_UNSPEC) 546 pai->ai_family = ex->e_af; 547 if (pai->ai_socktype == ANY && ex->e_socktype != ANY) 548 pai->ai_socktype = ex->e_socktype; 549 if (pai->ai_protocol == ANY && ex->e_protocol != ANY) 550 pai->ai_protocol = ex->e_protocol; 551 552 /* 553 * if the servname does not match socktype/protocol, ignore it. 554 */ 555 if (get_portmatch(pai, servname) != 0) 556 continue; 557 558 if (afai_unspec) 559 afai = afai_unspec; 560 else { 561 if ((afd = find_afd(pai->ai_family)) == NULL) 562 continue; 563 /* XXX assumes that afd points inside afdl[] */ 564 afai = afailist[afd - afdl]; 565 } 566 if (!afai) 567 continue; 568 569 error = explore_copy(pai, afai, &cur->ai_next); 570 if (error != 0) 571 goto bad; 572 573 while (cur && cur->ai_next) 574 cur = cur->ai_next; 575 } 576 577 /* 578 * ensure we return either: 579 * - error == 0, non-NULL *res 580 * - error != 0, NULL *res 581 */ 582 if (error == 0) { 583 if (sentinel.ai_next) { 584 /* 585 * If the returned entry is for an active connection, 586 * and the given name is not numeric, reorder the 587 * list, so that the application would try the list 588 * in the most efficient order. Since the head entry 589 * of the original list may contain ai_canonname and 590 * that entry may be moved elsewhere in the new list, 591 * we keep the pointer and will restore it in the new 592 * head entry. (Note that RFC3493 requires the head 593 * entry store it when requested by the caller). 594 */ 595 if (hints == NULL || !(hints->ai_flags & AI_PASSIVE)) { 596 if (!numeric) { 597 char *canonname; 598 599 canonname = 600 sentinel.ai_next->ai_canonname; 601 sentinel.ai_next->ai_canonname = NULL; 602 (void)reorder(&sentinel); 603 if (sentinel.ai_next->ai_canonname == 604 NULL) { 605 sentinel.ai_next->ai_canonname 606 = canonname; 607 } else if (canonname != NULL) 608 free(canonname); 609 } 610 } 611 *res = sentinel.ai_next; 612 } else 613 error = EAI_FAIL; 614 } 615 616bad: 617 if (afai_unspec) 618 freeaddrinfo(afai_unspec); 619 for (afd = afdl; afd->a_af; afd++) { 620 if (afailist[afd - afdl]) 621 freeaddrinfo(afailist[afd - afdl]); 622 } 623 if (!*res) 624 if (sentinel.ai_next) 625 freeaddrinfo(sentinel.ai_next); 626 627 return (error); 628} 629 630static int 631reorder(struct addrinfo *sentinel) 632{ 633 struct addrinfo *ai, **aip; 634 struct ai_order *aio; 635 int i, n; 636 struct policyhead policyhead; 637 638 /* count the number of addrinfo elements for sorting. */ 639 for (n = 0, ai = sentinel->ai_next; ai != NULL; ai = ai->ai_next, n++) 640 ; 641 642 /* 643 * If the number is small enough, we can skip the reordering process. 644 */ 645 if (n <= 1) 646 return(n); 647 648 /* allocate a temporary array for sort and initialization of it. */ 649 if ((aio = malloc(sizeof(*aio) * n)) == NULL) 650 return(n); /* give up reordering */ 651 memset(aio, 0, sizeof(*aio) * n); 652 653 /* retrieve address selection policy from the kernel */ 654 TAILQ_INIT(&policyhead); 655 if (!get_addrselectpolicy(&policyhead)) { 656 /* no policy is installed into kernel, we don't sort. */ 657 free(aio); 658 return (n); 659 } 660 661 for (i = 0, ai = sentinel->ai_next; i < n; ai = ai->ai_next, i++) { 662 aio[i].aio_ai = ai; 663 aio[i].aio_dstscope = gai_addr2scopetype(ai->ai_addr); 664 aio[i].aio_dstpolicy = match_addrselectpolicy(ai->ai_addr, 665 &policyhead); 666 set_source(&aio[i], &policyhead); 667 } 668 669 /* perform sorting. */ 670 qsort(aio, n, sizeof(*aio), comp_dst); 671 672 /* reorder the addrinfo chain. */ 673 for (i = 0, aip = &sentinel->ai_next; i < n; i++) { 674 *aip = aio[i].aio_ai; 675 aip = &aio[i].aio_ai->ai_next; 676 } 677 *aip = NULL; 678 679 /* cleanup and return */ 680 free(aio); 681 free_addrselectpolicy(&policyhead); 682 return(n); 683} 684 685static int 686get_addrselectpolicy(struct policyhead *head) 687{ 688#ifdef INET6 689 int mib[] = { CTL_NET, PF_INET6, IPPROTO_IPV6, IPV6CTL_ADDRCTLPOLICY }; 690 size_t l; 691 char *buf; 692 struct in6_addrpolicy *pol, *ep; 693 694 if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), NULL, &l, NULL, 0) < 0) 695 return (0); 696 if ((buf = malloc(l)) == NULL) 697 return (0); 698 if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), buf, &l, NULL, 0) < 0) { 699 free(buf); 700 return (0); 701 } 702 703 ep = (struct in6_addrpolicy *)(buf + l); 704 for (pol = (struct in6_addrpolicy *)buf; pol + 1 <= ep; pol++) { 705 struct policyqueue *new; 706 707 if ((new = malloc(sizeof(*new))) == NULL) { 708 free_addrselectpolicy(head); /* make the list empty */ 709 break; 710 } 711 new->pc_policy = *pol; 712 TAILQ_INSERT_TAIL(head, new, pc_entry); 713 } 714 715 free(buf); 716 return (1); 717#else 718 return (0); 719#endif 720} 721 722static void 723free_addrselectpolicy(struct policyhead *head) 724{ 725 struct policyqueue *ent, *nent; 726 727 for (ent = TAILQ_FIRST(head); ent; ent = nent) { 728 nent = TAILQ_NEXT(ent, pc_entry); 729 TAILQ_REMOVE(head, ent, pc_entry); 730 free(ent); 731 } 732} 733 734static struct policyqueue * 735match_addrselectpolicy(struct sockaddr *addr, struct policyhead *head) 736{ 737#ifdef INET6 738 struct policyqueue *ent, *bestent = NULL; 739 struct in6_addrpolicy *pol; 740 int matchlen, bestmatchlen = -1; 741 u_char *mp, *ep, *k, *p, m; 742 struct sockaddr_in6 key; 743 744 switch(addr->sa_family) { 745 case AF_INET6: 746 key = *(struct sockaddr_in6 *)addr; 747 break; 748 case AF_INET: 749 /* convert the address into IPv4-mapped IPv6 address. */ 750 memset(&key, 0, sizeof(key)); 751 key.sin6_family = AF_INET6; 752 key.sin6_len = sizeof(key); 753 key.sin6_addr.s6_addr[10] = 0xff; 754 key.sin6_addr.s6_addr[11] = 0xff; 755 memcpy(&key.sin6_addr.s6_addr[12], 756 &((struct sockaddr_in *)addr)->sin_addr, 4); 757 break; 758 default: 759 return(NULL); 760 } 761 762 for (ent = TAILQ_FIRST(head); ent; ent = TAILQ_NEXT(ent, pc_entry)) { 763 pol = &ent->pc_policy; 764 matchlen = 0; 765 766 mp = (u_char *)&pol->addrmask.sin6_addr; 767 ep = mp + 16; /* XXX: scope field? */ 768 k = (u_char *)&key.sin6_addr; 769 p = (u_char *)&pol->addr.sin6_addr; 770 for (; mp < ep && *mp; mp++, k++, p++) { 771 m = *mp; 772 if ((*k & m) != *p) 773 goto next; /* not match */ 774 if (m == 0xff) /* short cut for a typical case */ 775 matchlen += 8; 776 else { 777 while (m >= 0x80) { 778 matchlen++; 779 m <<= 1; 780 } 781 } 782 } 783 784 /* matched. check if this is better than the current best. */ 785 if (matchlen > bestmatchlen) { 786 bestent = ent; 787 bestmatchlen = matchlen; 788 } 789 790 next: 791 continue; 792 } 793 794 return(bestent); 795#else 796 return(NULL); 797#endif 798 799} 800 801static void 802set_source(struct ai_order *aio, struct policyhead *ph) 803{ 804 struct addrinfo ai = *aio->aio_ai; 805 struct sockaddr_storage ss; 806 socklen_t srclen; 807 int s; 808 809 /* set unspec ("no source is available"), just in case */ 810 aio->aio_srcsa.sa_family = AF_UNSPEC; 811 aio->aio_srcscope = -1; 812 813 switch(ai.ai_family) { 814 case AF_INET: 815#ifdef INET6 816 case AF_INET6: 817#endif 818 break; 819 default: /* ignore unsupported AFs explicitly */ 820 return; 821 } 822 823 /* XXX: make a dummy addrinfo to call connect() */ 824 ai.ai_socktype = SOCK_DGRAM; 825 ai.ai_protocol = IPPROTO_UDP; /* is UDP too specific? */ 826 ai.ai_next = NULL; 827 memset(&ss, 0, sizeof(ss)); 828 memcpy(&ss, ai.ai_addr, ai.ai_addrlen); 829 ai.ai_addr = (struct sockaddr *)&ss; 830 get_port(&ai, "1", 0); 831 832 /* open a socket to get the source address for the given dst */ 833 if ((s = _socket(ai.ai_family, ai.ai_socktype, ai.ai_protocol)) < 0) 834 return; /* give up */ 835 if (_connect(s, ai.ai_addr, ai.ai_addrlen) < 0) 836 goto cleanup; 837 srclen = ai.ai_addrlen; 838 if (_getsockname(s, &aio->aio_srcsa, &srclen) < 0) { 839 aio->aio_srcsa.sa_family = AF_UNSPEC; 840 goto cleanup; 841 } 842 aio->aio_srcscope = gai_addr2scopetype(&aio->aio_srcsa); 843 aio->aio_srcpolicy = match_addrselectpolicy(&aio->aio_srcsa, ph); 844 aio->aio_matchlen = matchlen(&aio->aio_srcsa, aio->aio_ai->ai_addr); 845#ifdef INET6 846 if (ai.ai_family == AF_INET6) { 847 struct in6_ifreq ifr6; 848 u_int32_t flags6; 849 850 memset(&ifr6, 0, sizeof(ifr6)); 851 memcpy(&ifr6.ifr_addr, ai.ai_addr, ai.ai_addrlen); 852 if (_ioctl(s, SIOCGIFAFLAG_IN6, &ifr6) == 0) { 853 flags6 = ifr6.ifr_ifru.ifru_flags6; 854 if ((flags6 & IN6_IFF_DEPRECATED)) 855 aio->aio_srcflag |= AIO_SRCFLAG_DEPRECATED; 856 } 857 } 858#endif 859 860 cleanup: 861 _close(s); 862 return; 863} 864 865static int 866matchlen(struct sockaddr *src, struct sockaddr *dst) 867{ 868 int match = 0; 869 u_char *s, *d; 870 u_char *lim, r; 871 int addrlen; 872 873 switch (src->sa_family) { 874#ifdef INET6 875 case AF_INET6: 876 s = (u_char *)&((struct sockaddr_in6 *)src)->sin6_addr; 877 d = (u_char *)&((struct sockaddr_in6 *)dst)->sin6_addr; 878 addrlen = sizeof(struct in6_addr); 879 lim = s + addrlen; 880 break; 881#endif 882 case AF_INET: 883 s = (u_char *)&((struct sockaddr_in *)src)->sin_addr; 884 d = (u_char *)&((struct sockaddr_in *)dst)->sin_addr; 885 addrlen = sizeof(struct in_addr); 886 lim = s + addrlen; 887 break; 888 default: 889 return(0); 890 } 891 892 while (s < lim) 893 if ((r = (*d++ ^ *s++)) != 0) { 894 while (r < addrlen * 8) { 895 match++; 896 r <<= 1; 897 } 898 break; 899 } else 900 match += 8; 901 return(match); 902} 903 904static int 905comp_dst(const void *arg1, const void *arg2) 906{ 907 const struct ai_order *dst1 = arg1, *dst2 = arg2; 908 909 /* 910 * Rule 1: Avoid unusable destinations. 911 * XXX: we currently do not consider if an appropriate route exists. 912 */ 913 if (dst1->aio_srcsa.sa_family != AF_UNSPEC && 914 dst2->aio_srcsa.sa_family == AF_UNSPEC) { 915 return(-1); 916 } 917 if (dst1->aio_srcsa.sa_family == AF_UNSPEC && 918 dst2->aio_srcsa.sa_family != AF_UNSPEC) { 919 return(1); 920 } 921 922 /* Rule 2: Prefer matching scope. */ 923 if (dst1->aio_dstscope == dst1->aio_srcscope && 924 dst2->aio_dstscope != dst2->aio_srcscope) { 925 return(-1); 926 } 927 if (dst1->aio_dstscope != dst1->aio_srcscope && 928 dst2->aio_dstscope == dst2->aio_srcscope) { 929 return(1); 930 } 931 932 /* Rule 3: Avoid deprecated addresses. */ 933 if (dst1->aio_srcsa.sa_family != AF_UNSPEC && 934 dst2->aio_srcsa.sa_family != AF_UNSPEC) { 935 if (!(dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) && 936 (dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) { 937 return(-1); 938 } 939 if ((dst1->aio_srcflag & AIO_SRCFLAG_DEPRECATED) && 940 !(dst2->aio_srcflag & AIO_SRCFLAG_DEPRECATED)) { 941 return(1); 942 } 943 } 944 945 /* Rule 4: Prefer home addresses. */ 946 /* XXX: not implemented yet */ 947 948 /* Rule 5: Prefer matching label. */ 949#ifdef INET6 950 if (dst1->aio_srcpolicy && dst1->aio_dstpolicy && 951 dst1->aio_srcpolicy->pc_policy.label == 952 dst1->aio_dstpolicy->pc_policy.label && 953 (dst2->aio_srcpolicy == NULL || dst2->aio_dstpolicy == NULL || 954 dst2->aio_srcpolicy->pc_policy.label != 955 dst2->aio_dstpolicy->pc_policy.label)) { 956 return(-1); 957 } 958 if (dst2->aio_srcpolicy && dst2->aio_dstpolicy && 959 dst2->aio_srcpolicy->pc_policy.label == 960 dst2->aio_dstpolicy->pc_policy.label && 961 (dst1->aio_srcpolicy == NULL || dst1->aio_dstpolicy == NULL || 962 dst1->aio_srcpolicy->pc_policy.label != 963 dst1->aio_dstpolicy->pc_policy.label)) { 964 return(1); 965 } 966#endif 967 968 /* Rule 6: Prefer higher precedence. */ 969#ifdef INET6 970 if (dst1->aio_dstpolicy && 971 (dst2->aio_dstpolicy == NULL || 972 dst1->aio_dstpolicy->pc_policy.preced > 973 dst2->aio_dstpolicy->pc_policy.preced)) { 974 return(-1); 975 } 976 if (dst2->aio_dstpolicy && 977 (dst1->aio_dstpolicy == NULL || 978 dst2->aio_dstpolicy->pc_policy.preced > 979 dst1->aio_dstpolicy->pc_policy.preced)) { 980 return(1); 981 } 982#endif 983 984 /* Rule 7: Prefer native transport. */ 985 /* XXX: not implemented yet */ 986 987 /* Rule 8: Prefer smaller scope. */ 988 if (dst1->aio_dstscope >= 0 && 989 dst1->aio_dstscope < dst2->aio_dstscope) { 990 return(-1); 991 } 992 if (dst2->aio_dstscope >= 0 && 993 dst2->aio_dstscope < dst1->aio_dstscope) { 994 return(1); 995 } 996 997 /* 998 * Rule 9: Use longest matching prefix. 999 * We compare the match length in a same AF only. 1000 */ 1001 if (dst1->aio_ai->ai_addr->sa_family == 1002 dst2->aio_ai->ai_addr->sa_family) { 1003 if (dst1->aio_matchlen > dst2->aio_matchlen) { 1004 return(-1); 1005 } 1006 if (dst1->aio_matchlen < dst2->aio_matchlen) { 1007 return(1); 1008 } 1009 } 1010 1011 /* Rule 10: Otherwise, leave the order unchanged. */ 1012 return(-1); 1013} 1014 1015/* 1016 * Copy from scope.c. 1017 * XXX: we should standardize the functions and link them as standard 1018 * library. 1019 */ 1020static int 1021gai_addr2scopetype(struct sockaddr *sa) 1022{ 1023#ifdef INET6 1024 struct sockaddr_in6 *sa6; 1025#endif 1026 struct sockaddr_in *sa4; 1027 1028 switch(sa->sa_family) { 1029#ifdef INET6 1030 case AF_INET6: 1031 sa6 = (struct sockaddr_in6 *)sa; 1032 if (IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr)) { 1033 /* just use the scope field of the multicast address */ 1034 return(sa6->sin6_addr.s6_addr[2] & 0x0f); 1035 } 1036 /* 1037 * Unicast addresses: map scope type to corresponding scope 1038 * value defined for multcast addresses. 1039 * XXX: hardcoded scope type values are bad... 1040 */ 1041 if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr)) 1042 return(1); /* node local scope */ 1043 if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr)) 1044 return(2); /* link-local scope */ 1045 if (IN6_IS_ADDR_SITELOCAL(&sa6->sin6_addr)) 1046 return(5); /* site-local scope */ 1047 return(14); /* global scope */ 1048 break; 1049#endif 1050 case AF_INET: 1051 /* 1052 * IPv4 pseudo scoping according to RFC 3484. 1053 */ 1054 sa4 = (struct sockaddr_in *)sa; 1055 /* IPv4 autoconfiguration addresses have link-local scope. */ 1056 if (((u_char *)&sa4->sin_addr)[0] == 169 && 1057 ((u_char *)&sa4->sin_addr)[1] == 254) 1058 return(2); 1059 /* Private addresses have site-local scope. */ 1060 if (((u_char *)&sa4->sin_addr)[0] == 10 || 1061 (((u_char *)&sa4->sin_addr)[0] == 172 && 1062 (((u_char *)&sa4->sin_addr)[1] & 0xf0) == 16) || 1063 (((u_char *)&sa4->sin_addr)[0] == 192 && 1064 ((u_char *)&sa4->sin_addr)[1] == 168)) 1065 return(14); /* XXX: It should be 5 unless NAT */ 1066 /* Loopback addresses have link-local scope. */ 1067 if (((u_char *)&sa4->sin_addr)[0] == 127) 1068 return(2); 1069 return(14); 1070 break; 1071 default: 1072 errno = EAFNOSUPPORT; /* is this a good error? */ 1073 return(-1); 1074 } 1075} 1076 1077static int 1078explore_copy(const struct addrinfo *pai, const struct addrinfo *src0, 1079 struct addrinfo **res) 1080{ 1081 int error; 1082 struct addrinfo sentinel, *cur; 1083 const struct addrinfo *src; 1084 1085 error = 0; 1086 sentinel.ai_next = NULL; 1087 cur = &sentinel; 1088 1089 for (src = src0; src != NULL; src = src->ai_next) { 1090 if (src->ai_family != pai->ai_family) 1091 continue; 1092 1093 cur->ai_next = copy_ai(src); 1094 if (!cur->ai_next) { 1095 error = EAI_MEMORY; 1096 goto fail; 1097 } 1098 1099 cur->ai_next->ai_socktype = pai->ai_socktype; 1100 cur->ai_next->ai_protocol = pai->ai_protocol; 1101 cur = cur->ai_next; 1102 } 1103 1104 *res = sentinel.ai_next; 1105 return 0; 1106 1107fail: 1108 freeaddrinfo(sentinel.ai_next); 1109 return error; 1110} 1111 1112/* 1113 * hostname == NULL. 1114 * passive socket -> anyaddr (0.0.0.0 or ::) 1115 * non-passive socket -> localhost (127.0.0.1 or ::1) 1116 */ 1117static int 1118explore_null(const struct addrinfo *pai, const char *servname, 1119 struct addrinfo **res) 1120{ 1121 int s; 1122 const struct afd *afd; 1123 struct addrinfo *ai; 1124 int error; 1125 1126 *res = NULL; 1127 ai = NULL; 1128 1129 /* 1130 * filter out AFs that are not supported by the kernel 1131 * XXX errno? 1132 */ 1133 s = _socket(pai->ai_family, SOCK_DGRAM, 0); 1134 if (s < 0) { 1135 if (errno != EMFILE) 1136 return 0; 1137 } else 1138 _close(s); 1139 1140 afd = find_afd(pai->ai_family); 1141 if (afd == NULL) 1142 return 0; 1143 1144 if (pai->ai_flags & AI_PASSIVE) { 1145 GET_AI(ai, afd, afd->a_addrany); 1146 GET_PORT(ai, servname); 1147 } else { 1148 GET_AI(ai, afd, afd->a_loopback); 1149 GET_PORT(ai, servname); 1150 } 1151 1152 *res = ai; 1153 return 0; 1154 1155free: 1156 if (ai != NULL) 1157 freeaddrinfo(ai); 1158 return error; 1159} 1160 1161/* 1162 * numeric hostname 1163 */ 1164static int 1165explore_numeric(const struct addrinfo *pai, const char *hostname, 1166 const char *servname, struct addrinfo **res, const char *canonname) 1167{ 1168 const struct afd *afd; 1169 struct addrinfo *ai; 1170 int error; 1171 char pton[PTON_MAX]; 1172 1173 *res = NULL; 1174 ai = NULL; 1175 1176 afd = find_afd(pai->ai_family); 1177 if (afd == NULL) 1178 return 0; 1179 1180 switch (afd->a_af) { 1181 case AF_INET: 1182 /* 1183 * RFC3493 requires getaddrinfo() to accept AF_INET formats 1184 * that are accepted by inet_addr() and its family. The 1185 * accepted forms includes the "classful" one, which inet_pton 1186 * does not accept. So we need to separate the case for 1187 * AF_INET. 1188 */ 1189 if (inet_aton(hostname, (struct in_addr *)pton) != 1) 1190 return 0; 1191 break; 1192 default: 1193 if (inet_pton(afd->a_af, hostname, pton) != 1) 1194 return 0; 1195 break; 1196 } 1197 1198 if (pai->ai_family == afd->a_af) { 1199 GET_AI(ai, afd, pton); 1200 GET_PORT(ai, servname); 1201 if ((pai->ai_flags & AI_CANONNAME)) { 1202 /* 1203 * Set the numeric address itself as the canonical 1204 * name, based on a clarification in RFC3493. 1205 */ 1206 GET_CANONNAME(ai, canonname); 1207 } 1208 } else { 1209 /* 1210 * XXX: This should not happen since we already matched the AF 1211 * by find_afd. 1212 */ 1213 ERR(EAI_FAMILY); 1214 } 1215 1216 *res = ai; 1217 return 0; 1218 1219free: 1220bad: 1221 if (ai != NULL) 1222 freeaddrinfo(ai); 1223 return error; 1224} 1225 1226/* 1227 * numeric hostname with scope 1228 */ 1229static int 1230explore_numeric_scope(const struct addrinfo *pai, const char *hostname, 1231 const char *servname, struct addrinfo **res) 1232{ 1233#if !defined(SCOPE_DELIMITER) || !defined(INET6) 1234 return explore_numeric(pai, hostname, servname, res, hostname); 1235#else 1236 const struct afd *afd; 1237 struct addrinfo *cur; 1238 int error; 1239 char *cp, *hostname2 = NULL, *scope, *addr; 1240 struct sockaddr_in6 *sin6; 1241 1242 afd = find_afd(pai->ai_family); 1243 if (afd == NULL) 1244 return 0; 1245 1246 if (!afd->a_scoped) 1247 return explore_numeric(pai, hostname, servname, res, hostname); 1248 1249 cp = strchr(hostname, SCOPE_DELIMITER); 1250 if (cp == NULL) 1251 return explore_numeric(pai, hostname, servname, res, hostname); 1252 1253 /* 1254 * Handle special case of <scoped_address><delimiter><scope id> 1255 */ 1256 hostname2 = strdup(hostname); 1257 if (hostname2 == NULL) 1258 return EAI_MEMORY; 1259 /* terminate at the delimiter */ 1260 hostname2[cp - hostname] = '\0'; 1261 addr = hostname2; 1262 scope = cp + 1; 1263 1264 error = explore_numeric(pai, addr, servname, res, hostname); 1265 if (error == 0) { 1266 u_int32_t scopeid; 1267 1268 for (cur = *res; cur; cur = cur->ai_next) { 1269 if (cur->ai_family != AF_INET6) 1270 continue; 1271 sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr; 1272 if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) { 1273 free(hostname2); 1274 freeaddrinfo(*res); 1275 *res = NULL; 1276 return(EAI_NONAME); /* XXX: is return OK? */ 1277 } 1278 sin6->sin6_scope_id = scopeid; 1279 } 1280 } 1281 1282 free(hostname2); 1283 1284 if (error && *res) { 1285 freeaddrinfo(*res); 1286 *res = NULL; 1287 } 1288 return error; 1289#endif 1290} 1291 1292static int 1293get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str) 1294{ 1295 if ((pai->ai_flags & AI_CANONNAME) != 0) { 1296 ai->ai_canonname = strdup(str); 1297 if (ai->ai_canonname == NULL) 1298 return EAI_MEMORY; 1299 } 1300 return 0; 1301} 1302 1303static struct addrinfo * 1304get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr) 1305{ 1306 char *p; 1307 struct addrinfo *ai; 1308#ifdef FAITH 1309 struct in6_addr faith_prefix; 1310 char *fp_str; 1311 int translate = 0; 1312#endif 1313 1314#ifdef FAITH 1315 /* 1316 * Transfrom an IPv4 addr into a special IPv6 addr format for 1317 * IPv6->IPv4 translation gateway. (only TCP is supported now) 1318 * 1319 * +-----------------------------------+------------+ 1320 * | faith prefix part (12 bytes) | embedded | 1321 * | | IPv4 addr part (4 bytes) 1322 * +-----------------------------------+------------+ 1323 * 1324 * faith prefix part is specified as ascii IPv6 addr format 1325 * in environmental variable GAI. 1326 * For FAITH to work correctly, routing to faith prefix must be 1327 * setup toward a machine where a FAITH daemon operates. 1328 * Also, the machine must enable some mechanizm 1329 * (e.g. faith interface hack) to divert those packet with 1330 * faith prefixed destination addr to user-land FAITH daemon. 1331 */ 1332 fp_str = getenv("GAI"); 1333 if (fp_str && inet_pton(AF_INET6, fp_str, &faith_prefix) == 1 && 1334 afd->a_af == AF_INET && pai->ai_socktype == SOCK_STREAM) { 1335 u_int32_t v4a; 1336 u_int8_t v4a_top; 1337 1338 memcpy(&v4a, addr, sizeof v4a); 1339 v4a_top = v4a >> IN_CLASSA_NSHIFT; 1340 if (!IN_MULTICAST(v4a) && !IN_EXPERIMENTAL(v4a) && 1341 v4a_top != 0 && v4a != IN_LOOPBACKNET) { 1342 afd = &afdl[N_INET6]; 1343 memcpy(&faith_prefix.s6_addr[12], addr, 1344 sizeof(struct in_addr)); 1345 translate = 1; 1346 } 1347 } 1348#endif 1349 1350 ai = (struct addrinfo *)malloc(sizeof(struct addrinfo) 1351 + (afd->a_socklen)); 1352 if (ai == NULL) 1353 return NULL; 1354 1355 memcpy(ai, pai, sizeof(struct addrinfo)); 1356 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1); 1357 memset(ai->ai_addr, 0, (size_t)afd->a_socklen); 1358 ai->ai_addr->sa_len = afd->a_socklen; 1359 ai->ai_addrlen = afd->a_socklen; 1360 ai->ai_addr->sa_family = ai->ai_family = afd->a_af; 1361 p = (char *)(void *)(ai->ai_addr); 1362#ifdef FAITH 1363 if (translate == 1) 1364 memcpy(p + afd->a_off, &faith_prefix, (size_t)afd->a_addrlen); 1365 else 1366#endif 1367 memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen); 1368 return ai; 1369} 1370 1371/* XXX need to malloc() the same way we do from other functions! */ 1372static struct addrinfo * 1373copy_ai(const struct addrinfo *pai) 1374{ 1375 struct addrinfo *ai; 1376 size_t l; 1377 1378 l = sizeof(*ai) + pai->ai_addrlen; 1379 if ((ai = (struct addrinfo *)malloc(l)) == NULL) 1380 return NULL; 1381 memset(ai, 0, l); 1382 memcpy(ai, pai, sizeof(*ai)); 1383 ai->ai_addr = (struct sockaddr *)(void *)(ai + 1); 1384 memcpy(ai->ai_addr, pai->ai_addr, pai->ai_addrlen); 1385 1386 if (pai->ai_canonname) { 1387 l = strlen(pai->ai_canonname) + 1; 1388 if ((ai->ai_canonname = malloc(l)) == NULL) { 1389 free(ai); 1390 return NULL; 1391 } 1392 strlcpy(ai->ai_canonname, pai->ai_canonname, l); 1393 } else { 1394 /* just to make sure */ 1395 ai->ai_canonname = NULL; 1396 } 1397 1398 ai->ai_next = NULL; 1399 1400 return ai; 1401} 1402 1403static int 1404get_portmatch(const struct addrinfo *ai, const char *servname) 1405{ 1406 1407 /* get_port does not touch first argument when matchonly == 1. */ 1408 /* LINTED const cast */ 1409 return get_port((struct addrinfo *)ai, servname, 1); 1410} 1411 1412static int 1413get_port(struct addrinfo *ai, const char *servname, int matchonly) 1414{ 1415 const char *proto; 1416 struct servent *sp; 1417 int port, error; 1418 int allownumeric; 1419 1420 if (servname == NULL) 1421 return 0; 1422 switch (ai->ai_family) { 1423 case AF_INET: 1424#ifdef AF_INET6 1425 case AF_INET6: 1426#endif 1427 break; 1428 default: 1429 return 0; 1430 } 1431 1432 switch (ai->ai_socktype) { 1433 case SOCK_RAW: 1434 return EAI_SERVICE; 1435 case SOCK_DGRAM: 1436 case SOCK_STREAM: 1437 case SOCK_SEQPACKET: 1438 allownumeric = 1; 1439 break; 1440 case ANY: 1441 switch (ai->ai_family) { 1442 case AF_INET: 1443#ifdef AF_INET6 1444 case AF_INET6: 1445#endif 1446 allownumeric = 1; 1447 break; 1448 default: 1449 allownumeric = 0; 1450 break; 1451 } 1452 break; 1453 default: 1454 return EAI_SOCKTYPE; 1455 } 1456 1457 error = str2number(servname, &port); 1458 if (error == 0) { 1459 if (!allownumeric) 1460 return EAI_SERVICE; 1461 if (port < 0 || port > 65535) 1462 return EAI_SERVICE; 1463 port = htons(port); 1464 } else { 1465 if (ai->ai_flags & AI_NUMERICSERV) 1466 return EAI_NONAME; 1467 1468 switch (ai->ai_protocol) { 1469 case IPPROTO_UDP: 1470 proto = "udp"; 1471 break; 1472 case IPPROTO_TCP: 1473 proto = "tcp"; 1474 break; 1475 case IPPROTO_SCTP: 1476 proto = "sctp"; 1477 break; 1478 default: 1479 proto = NULL; 1480 break; 1481 } 1482 1483 if ((sp = getservbyname(servname, proto)) == NULL) 1484 return EAI_SERVICE; 1485 port = sp->s_port; 1486 } 1487 1488 if (!matchonly) { 1489 switch (ai->ai_family) { 1490 case AF_INET: 1491 ((struct sockaddr_in *)(void *) 1492 ai->ai_addr)->sin_port = port; 1493 break; 1494#ifdef INET6 1495 case AF_INET6: 1496 ((struct sockaddr_in6 *)(void *) 1497 ai->ai_addr)->sin6_port = port; 1498 break; 1499#endif 1500 } 1501 } 1502 1503 return 0; 1504} 1505 1506static const struct afd * 1507find_afd(int af) 1508{ 1509 const struct afd *afd; 1510 1511 if (af == PF_UNSPEC) 1512 return NULL; 1513 for (afd = afdl; afd->a_af; afd++) { 1514 if (afd->a_af == af) 1515 return afd; 1516 } 1517 return NULL; 1518} 1519 1520/* 1521 * post-2553: AI_ADDRCONFIG check. if we use getipnodeby* as backend, backend 1522 * will take care of it. 1523 * the semantics of AI_ADDRCONFIG is not defined well. we are not sure 1524 * if the code is right or not. 1525 * 1526 * XXX PF_UNSPEC -> PF_INET6 + PF_INET mapping needs to be in sync with 1527 * _dns_getaddrinfo. 1528 */ 1529static int 1530addrconfig(struct addrinfo *pai) 1531{ 1532 int s, af; 1533 1534 /* 1535 * TODO: 1536 * Note that implementation dependent test for address 1537 * configuration should be done everytime called 1538 * (or apropriate interval), 1539 * because addresses will be dynamically assigned or deleted. 1540 */ 1541 af = pai->ai_family; 1542 if (af == AF_UNSPEC) { 1543 if ((s = _socket(AF_INET6, SOCK_DGRAM, 0)) < 0) 1544 af = AF_INET; 1545 else { 1546 _close(s); 1547 if ((s = _socket(AF_INET, SOCK_DGRAM, 0)) < 0) 1548 af = AF_INET6; 1549 else 1550 _close(s); 1551 } 1552 } 1553 if (af != AF_UNSPEC) { 1554 if ((s = _socket(af, SOCK_DGRAM, 0)) < 0) 1555 return 0; 1556 _close(s); 1557 } 1558 pai->ai_family = af; 1559 return 1; 1560} 1561 1562#ifdef INET6 1563/* convert a string to a scope identifier. XXX: IPv6 specific */ 1564static int 1565ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid) 1566{ 1567 u_long lscopeid; 1568 struct in6_addr *a6; 1569 char *ep; 1570 1571 a6 = &sin6->sin6_addr; 1572 1573 /* empty scopeid portion is invalid */ 1574 if (*scope == '\0') 1575 return -1; 1576 1577 if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6) || 1578 IN6_IS_ADDR_MC_NODELOCAL(a6)) { 1579 /* 1580 * We currently assume a one-to-one mapping between links 1581 * and interfaces, so we simply use interface indices for 1582 * like-local scopes. 1583 */ 1584 *scopeid = if_nametoindex(scope); 1585 if (*scopeid == 0) 1586 goto trynumeric; 1587 return 0; 1588 } 1589 1590 /* still unclear about literal, allow numeric only - placeholder */ 1591 if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6)) 1592 goto trynumeric; 1593 if (IN6_IS_ADDR_MC_ORGLOCAL(a6)) 1594 goto trynumeric; 1595 else 1596 goto trynumeric; /* global */ 1597 1598 /* try to convert to a numeric id as a last resort */ 1599 trynumeric: 1600 errno = 0; 1601 lscopeid = strtoul(scope, &ep, 10); 1602 *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL); 1603 if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid) 1604 return 0; 1605 else 1606 return -1; 1607} 1608#endif 1609 1610 1611#ifdef NS_CACHING 1612static int 1613addrinfo_id_func(char *buffer, size_t *buffer_size, va_list ap, 1614 void *cache_mdata) 1615{ 1616 res_state statp; 1617 u_long res_options; 1618 1619 const int op_id = 0; /* identifies the getaddrinfo for the cache */ 1620 char *hostname; 1621 struct addrinfo *hints; 1622 1623 char *p; 1624 int ai_flags, ai_family, ai_socktype, ai_protocol; 1625 size_t desired_size, size; 1626 1627 statp = __res_state(); 1628 res_options = statp->options & (RES_RECURSE | RES_DEFNAMES | 1629 RES_DNSRCH | RES_NOALIASES | RES_USE_INET6); 1630 1631 hostname = va_arg(ap, char *); 1632 hints = va_arg(ap, struct addrinfo *); 1633 1634 desired_size = sizeof(res_options) + sizeof(int) + sizeof(int) * 4; 1635 if (hostname != NULL) { 1636 size = strlen(hostname); 1637 desired_size += size + 1; 1638 } else 1639 size = 0; 1640 1641 if (desired_size > *buffer_size) { 1642 *buffer_size = desired_size; 1643 return (NS_RETURN); 1644 } 1645 1646 if (hints == NULL) 1647 ai_flags = ai_family = ai_socktype = ai_protocol = 0; 1648 else { 1649 ai_flags = hints->ai_flags; 1650 ai_family = hints->ai_family; 1651 ai_socktype = hints->ai_socktype; 1652 ai_protocol = hints->ai_protocol; 1653 } 1654 1655 p = buffer; 1656 memcpy(p, &res_options, sizeof(res_options)); 1657 p += sizeof(res_options); 1658 1659 memcpy(p, &op_id, sizeof(int)); 1660 p += sizeof(int); 1661 1662 memcpy(p, &ai_flags, sizeof(int)); 1663 p += sizeof(int); 1664 1665 memcpy(p, &ai_family, sizeof(int)); 1666 p += sizeof(int); 1667 1668 memcpy(p, &ai_socktype, sizeof(int)); 1669 p += sizeof(int); 1670 1671 memcpy(p, &ai_protocol, sizeof(int)); 1672 p += sizeof(int); 1673 1674 if (hostname != NULL) 1675 memcpy(p, hostname, size); 1676 1677 *buffer_size = desired_size; 1678 return (NS_SUCCESS); 1679} 1680 1681static int 1682addrinfo_marshal_func(char *buffer, size_t *buffer_size, void *retval, 1683 va_list ap, void *cache_mdata) 1684{ 1685 struct addrinfo *ai, *cai; 1686 char *p; 1687 size_t desired_size, size, ai_size; 1688 1689 ai = *((struct addrinfo **)retval); 1690 1691 desired_size = sizeof(size_t); 1692 ai_size = 0; 1693 for (cai = ai; cai != NULL; cai = cai->ai_next) { 1694 desired_size += sizeof(struct addrinfo) + cai->ai_addrlen; 1695 if (cai->ai_canonname != NULL) 1696 desired_size += sizeof(size_t) + 1697 strlen(cai->ai_canonname); 1698 ++ai_size; 1699 } 1700 1701 if (desired_size > *buffer_size) { 1702 /* this assignment is here for future use */ 1703 errno = ERANGE; 1704 *buffer_size = desired_size; 1705 return (NS_RETURN); 1706 } 1707 1708 memset(buffer, 0, desired_size); 1709 p = buffer; 1710 1711 memcpy(p, &ai_size, sizeof(size_t)); 1712 p += sizeof(size_t); 1713 for (cai = ai; cai != NULL; cai = cai->ai_next) { 1714 memcpy(p, cai, sizeof(struct addrinfo)); 1715 p += sizeof(struct addrinfo); 1716 1717 memcpy(p, cai->ai_addr, cai->ai_addrlen); 1718 p += cai->ai_addrlen; 1719 1720 if (cai->ai_canonname != NULL) { 1721 size = strlen(cai->ai_canonname); 1722 memcpy(p, &size, sizeof(size_t)); 1723 p += sizeof(size_t); 1724 1725 memcpy(p, cai->ai_canonname, size); 1726 p += size; 1727 } 1728 } 1729 1730 return (NS_SUCCESS); 1731} 1732 1733static int 1734addrinfo_unmarshal_func(char *buffer, size_t buffer_size, void *retval, 1735 va_list ap, void *cache_mdata) 1736{ 1737 struct addrinfo new_ai, *result, *sentinel, *lasts; 1738 1739 char *p; 1740 size_t ai_size, ai_i, size; 1741 1742 p = buffer; 1743 memcpy(&ai_size, p, sizeof(size_t)); 1744 p += sizeof(size_t); 1745 1746 result = NULL; 1747 lasts = NULL; 1748 for (ai_i = 0; ai_i < ai_size; ++ai_i) { 1749 memcpy(&new_ai, p, sizeof(struct addrinfo)); 1750 p += sizeof(struct addrinfo); 1751 size = new_ai.ai_addrlen + sizeof(struct addrinfo) + 1752 _ALIGNBYTES; 1753 1754 sentinel = (struct addrinfo *)malloc(size); 1755 memset(sentinel, 0, size); 1756 1757 memcpy(sentinel, &new_ai, sizeof(struct addrinfo)); 1758 sentinel->ai_addr = (struct sockaddr *)_ALIGN((char *)sentinel + 1759 sizeof(struct addrinfo)); 1760 1761 memcpy(sentinel->ai_addr, p, new_ai.ai_addrlen); 1762 p += new_ai.ai_addrlen; 1763 1764 if (new_ai.ai_canonname != NULL) { 1765 memcpy(&size, p, sizeof(size_t)); 1766 p += sizeof(size_t); 1767 1768 sentinel->ai_canonname = (char *)malloc(size + 1); 1769 memset(sentinel->ai_canonname, 0, size + 1); 1770 1771 memcpy(sentinel->ai_canonname, p, size); 1772 p += size; 1773 } 1774 1775 if (result == NULL) { 1776 result = sentinel; 1777 lasts = sentinel; 1778 } else { 1779 lasts->ai_next = sentinel; 1780 lasts = sentinel; 1781 } 1782 } 1783 1784 *((struct addrinfo **)retval) = result; 1785 return (NS_SUCCESS); 1786} 1787#endif /* NS_CACHING */ 1788 1789/* 1790 * FQDN hostname, DNS lookup 1791 */ 1792static int 1793explore_fqdn(const struct addrinfo *pai, const char *hostname, 1794 const char *servname, struct addrinfo **res) 1795{ 1796 struct addrinfo *result; 1797 struct addrinfo *cur; 1798 int error = 0; 1799 1800#ifdef NS_CACHING 1801 static const nss_cache_info cache_info = 1802 NS_COMMON_CACHE_INFO_INITIALIZER( 1803 hosts, NULL, addrinfo_id_func, addrinfo_marshal_func, 1804 addrinfo_unmarshal_func); 1805#endif 1806 static const ns_dtab dtab[] = { 1807 NS_FILES_CB(_files_getaddrinfo, NULL) 1808 { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */ 1809 NS_NIS_CB(_yp_getaddrinfo, NULL) 1810#ifdef NS_CACHING 1811 NS_CACHE_CB(&cache_info) 1812#endif 1813 { 0 } 1814 }; 1815 1816 result = NULL; 1817 1818 /* 1819 * if the servname does not match socktype/protocol, ignore it. 1820 */ 1821 if (get_portmatch(pai, servname) != 0) 1822 return 0; 1823 1824 switch (_nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo", 1825 default_dns_files, hostname, pai)) { 1826 case NS_TRYAGAIN: 1827 error = EAI_AGAIN; 1828 goto free; 1829 case NS_UNAVAIL: 1830 error = EAI_FAIL; 1831 goto free; 1832 case NS_NOTFOUND: 1833 error = EAI_NONAME; 1834 goto free; 1835 case NS_SUCCESS: 1836 error = 0; 1837 for (cur = result; cur; cur = cur->ai_next) { 1838 GET_PORT(cur, servname); 1839 /* canonname should be filled already */ 1840 } 1841 break; 1842 } 1843 1844 *res = result; 1845 1846 return 0; 1847 1848free: 1849 if (result) 1850 freeaddrinfo(result); 1851 return error; 1852} 1853 1854#ifdef DEBUG 1855static const char AskedForGot[] = 1856 "gethostby*.getanswer: asked for \"%s\", got \"%s\""; 1857#endif 1858 1859static struct addrinfo * 1860getanswer(const querybuf *answer, int anslen, const char *qname, int qtype, 1861 const struct addrinfo *pai, res_state res) 1862{ 1863 struct addrinfo sentinel, *cur; 1864 struct addrinfo ai; 1865 const struct afd *afd; 1866 char *canonname; 1867 const HEADER *hp; 1868 const u_char *cp; 1869 int n; 1870 const u_char *eom; 1871 char *bp, *ep; 1872 int type, class, ancount, qdcount; 1873 int haveanswer, had_error; 1874 char tbuf[MAXDNAME]; 1875 int (*name_ok)(const char *); 1876 char hostbuf[8*1024]; 1877 1878 memset(&sentinel, 0, sizeof(sentinel)); 1879 cur = &sentinel; 1880 1881 canonname = NULL; 1882 eom = answer->buf + anslen; 1883 switch (qtype) { 1884 case T_A: 1885 case T_AAAA: 1886 case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/ 1887 name_ok = res_hnok; 1888 break; 1889 default: 1890 return (NULL); /* XXX should be abort(); */ 1891 } 1892 /* 1893 * find first satisfactory answer 1894 */ 1895 hp = &answer->hdr; 1896 ancount = ntohs(hp->ancount); 1897 qdcount = ntohs(hp->qdcount); 1898 bp = hostbuf; 1899 ep = hostbuf + sizeof hostbuf; 1900 cp = answer->buf + HFIXEDSZ; 1901 if (qdcount != 1) { 1902 RES_SET_H_ERRNO(res, NO_RECOVERY); 1903 return (NULL); 1904 } 1905 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 1906 if ((n < 0) || !(*name_ok)(bp)) { 1907 RES_SET_H_ERRNO(res, NO_RECOVERY); 1908 return (NULL); 1909 } 1910 cp += n + QFIXEDSZ; 1911 if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) { 1912 /* res_send() has already verified that the query name is the 1913 * same as the one we sent; this just gets the expanded name 1914 * (i.e., with the succeeding search-domain tacked on). 1915 */ 1916 n = strlen(bp) + 1; /* for the \0 */ 1917 if (n >= MAXHOSTNAMELEN) { 1918 RES_SET_H_ERRNO(res, NO_RECOVERY); 1919 return (NULL); 1920 } 1921 canonname = bp; 1922 bp += n; 1923 /* The qname can be abbreviated, but h_name is now absolute. */ 1924 qname = canonname; 1925 } 1926 haveanswer = 0; 1927 had_error = 0; 1928 while (ancount-- > 0 && cp < eom && !had_error) { 1929 n = dn_expand(answer->buf, eom, cp, bp, ep - bp); 1930 if ((n < 0) || !(*name_ok)(bp)) { 1931 had_error++; 1932 continue; 1933 } 1934 cp += n; /* name */ 1935 type = _getshort(cp); 1936 cp += INT16SZ; /* type */ 1937 class = _getshort(cp); 1938 cp += INT16SZ + INT32SZ; /* class, TTL */ 1939 n = _getshort(cp); 1940 cp += INT16SZ; /* len */ 1941 if (class != C_IN) { 1942 /* XXX - debug? syslog? */ 1943 cp += n; 1944 continue; /* XXX - had_error++ ? */ 1945 } 1946 if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) && 1947 type == T_CNAME) { 1948 n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); 1949 if ((n < 0) || !(*name_ok)(tbuf)) { 1950 had_error++; 1951 continue; 1952 } 1953 cp += n; 1954 /* Get canonical name. */ 1955 n = strlen(tbuf) + 1; /* for the \0 */ 1956 if (n > ep - bp || n >= MAXHOSTNAMELEN) { 1957 had_error++; 1958 continue; 1959 } 1960 strlcpy(bp, tbuf, ep - bp); 1961 canonname = bp; 1962 bp += n; 1963 continue; 1964 } 1965 if (qtype == T_ANY) { 1966 if (!(type == T_A || type == T_AAAA)) { 1967 cp += n; 1968 continue; 1969 } 1970 } else if (type != qtype) { 1971#ifdef DEBUG 1972 if (type != T_KEY && type != T_SIG && 1973 type != ns_t_dname) 1974 syslog(LOG_NOTICE|LOG_AUTH, 1975 "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"", 1976 qname, p_class(C_IN), p_type(qtype), 1977 p_type(type)); 1978#endif 1979 cp += n; 1980 continue; /* XXX - had_error++ ? */ 1981 } 1982 switch (type) { 1983 case T_A: 1984 case T_AAAA: 1985 if (strcasecmp(canonname, bp) != 0) { 1986#ifdef DEBUG 1987 syslog(LOG_NOTICE|LOG_AUTH, 1988 AskedForGot, canonname, bp); 1989#endif 1990 cp += n; 1991 continue; /* XXX - had_error++ ? */ 1992 } 1993 if (type == T_A && n != INADDRSZ) { 1994 cp += n; 1995 continue; 1996 } 1997 if (type == T_AAAA && n != IN6ADDRSZ) { 1998 cp += n; 1999 continue; 2000 } 2001#ifdef FILTER_V4MAPPED 2002 if (type == T_AAAA) { 2003 struct in6_addr in6; 2004 memcpy(&in6, cp, sizeof(in6)); 2005 if (IN6_IS_ADDR_V4MAPPED(&in6)) { 2006 cp += n; 2007 continue; 2008 } 2009 } 2010#endif 2011 if (!haveanswer) { 2012 int nn; 2013 2014 canonname = bp; 2015 nn = strlen(bp) + 1; /* for the \0 */ 2016 bp += nn; 2017 } 2018 2019 /* don't overwrite pai */ 2020 ai = *pai; 2021 ai.ai_family = (type == T_A) ? AF_INET : AF_INET6; 2022 afd = find_afd(ai.ai_family); 2023 if (afd == NULL) { 2024 cp += n; 2025 continue; 2026 } 2027 cur->ai_next = get_ai(&ai, afd, (const char *)cp); 2028 if (cur->ai_next == NULL) 2029 had_error++; 2030 while (cur && cur->ai_next) 2031 cur = cur->ai_next; 2032 cp += n; 2033 break; 2034 default: 2035 abort(); 2036 } 2037 if (!had_error) 2038 haveanswer++; 2039 } 2040 if (haveanswer) { 2041#if defined(RESOLVSORT) 2042 /* 2043 * We support only IPv4 address for backward 2044 * compatibility against gethostbyname(3). 2045 */ 2046 if (res->nsort && qtype == T_A) { 2047 if (addr4sort(&sentinel, res) < 0) { 2048 freeaddrinfo(sentinel.ai_next); 2049 RES_SET_H_ERRNO(res, NO_RECOVERY); 2050 return NULL; 2051 } 2052 } 2053#endif /*RESOLVSORT*/ 2054 if (!canonname) 2055 (void)get_canonname(pai, sentinel.ai_next, qname); 2056 else 2057 (void)get_canonname(pai, sentinel.ai_next, canonname); 2058 RES_SET_H_ERRNO(res, NETDB_SUCCESS); 2059 return sentinel.ai_next; 2060 } 2061 2062 RES_SET_H_ERRNO(res, NO_RECOVERY); 2063 return NULL; 2064} 2065 2066#ifdef RESOLVSORT 2067struct addr_ptr { 2068 struct addrinfo *ai; 2069 int aval; 2070}; 2071 2072static int 2073addr4sort(struct addrinfo *sentinel, res_state res) 2074{ 2075 struct addrinfo *ai; 2076 struct addr_ptr *addrs, addr; 2077 struct sockaddr_in *sin; 2078 int naddrs, i, j; 2079 int needsort = 0; 2080 2081 if (!sentinel) 2082 return -1; 2083 naddrs = 0; 2084 for (ai = sentinel->ai_next; ai; ai = ai->ai_next) 2085 naddrs++; 2086 if (naddrs < 2) 2087 return 0; /* We don't need sorting. */ 2088 if ((addrs = malloc(sizeof(struct addr_ptr) * naddrs)) == NULL) 2089 return -1; 2090 i = 0; 2091 for (ai = sentinel->ai_next; ai; ai = ai->ai_next) { 2092 sin = (struct sockaddr_in *)ai->ai_addr; 2093 for (j = 0; (unsigned)j < res->nsort; j++) { 2094 if (res->sort_list[j].addr.s_addr == 2095 (sin->sin_addr.s_addr & res->sort_list[j].mask)) 2096 break; 2097 } 2098 addrs[i].ai = ai; 2099 addrs[i].aval = j; 2100 if (needsort == 0 && i > 0 && j < addrs[i - 1].aval) 2101 needsort = i; 2102 i++; 2103 } 2104 if (!needsort) { 2105 free(addrs); 2106 return 0; 2107 } 2108 2109 while (needsort < naddrs) { 2110 for (j = needsort - 1; j >= 0; j--) { 2111 if (addrs[j].aval > addrs[j+1].aval) { 2112 addr = addrs[j]; 2113 addrs[j] = addrs[j + 1]; 2114 addrs[j + 1] = addr; 2115 } else 2116 break; 2117 } 2118 needsort++; 2119 } 2120 2121 ai = sentinel; 2122 for (i = 0; i < naddrs; ++i) { 2123 ai->ai_next = addrs[i].ai; 2124 ai = ai->ai_next; 2125 } 2126 ai->ai_next = NULL; 2127 free(addrs); 2128 return 0; 2129} 2130#endif /*RESOLVSORT*/ 2131 2132/*ARGSUSED*/ 2133static int 2134_dns_getaddrinfo(void *rv, void *cb_data, va_list ap) 2135{ 2136 struct addrinfo *ai; 2137 querybuf *buf, *buf2; 2138 const char *hostname; 2139 const struct addrinfo *pai; 2140 struct addrinfo sentinel, *cur; 2141 struct res_target q, q2; 2142 res_state res; 2143 2144 hostname = va_arg(ap, char *); 2145 pai = va_arg(ap, const struct addrinfo *); 2146 2147 memset(&q, 0, sizeof(q)); 2148 memset(&q2, 0, sizeof(q2)); 2149 memset(&sentinel, 0, sizeof(sentinel)); 2150 cur = &sentinel; 2151 2152 buf = malloc(sizeof(*buf)); 2153 if (!buf) { 2154 RES_SET_H_ERRNO(res, NETDB_INTERNAL); 2155 return NS_NOTFOUND; 2156 } 2157 buf2 = malloc(sizeof(*buf2)); 2158 if (!buf2) { 2159 free(buf); 2160 RES_SET_H_ERRNO(res, NETDB_INTERNAL); 2161 return NS_NOTFOUND; 2162 } 2163 2164 switch (pai->ai_family) { 2165 case AF_UNSPEC: 2166 q.name = hostname; 2167 q.qclass = C_IN; 2168 q.qtype = T_A; 2169 q.answer = buf->buf; 2170 q.anslen = sizeof(buf->buf); 2171 q.next = &q2; 2172 q2.name = hostname; 2173 q2.qclass = C_IN; 2174 q2.qtype = T_AAAA; 2175 q2.answer = buf2->buf; 2176 q2.anslen = sizeof(buf2->buf); 2177 break; 2178 case AF_INET: 2179 q.name = hostname; 2180 q.qclass = C_IN; 2181 q.qtype = T_A; 2182 q.answer = buf->buf; 2183 q.anslen = sizeof(buf->buf); 2184 break; 2185 case AF_INET6: 2186 q.name = hostname; 2187 q.qclass = C_IN; 2188 q.qtype = T_AAAA; 2189 q.answer = buf->buf; 2190 q.anslen = sizeof(buf->buf); 2191 break; 2192 default: 2193 free(buf); 2194 free(buf2); 2195 return NS_UNAVAIL; 2196 } 2197 2198 res = __res_state(); 2199 if ((res->options & RES_INIT) == 0 && res_ninit(res) == -1) { 2200 RES_SET_H_ERRNO(res, NETDB_INTERNAL); 2201 free(buf); 2202 free(buf2); 2203 return NS_NOTFOUND; 2204 } 2205 2206 if (res_searchN(hostname, &q, res) < 0) { 2207 free(buf); 2208 free(buf2); 2209 return NS_NOTFOUND; 2210 } 2211 /* prefer IPv6 */ 2212 if (q.next) { 2213 ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai, res); 2214 if (ai) { 2215 cur->ai_next = ai; 2216 while (cur && cur->ai_next) 2217 cur = cur->ai_next; 2218 } 2219 } 2220 ai = getanswer(buf, q.n, q.name, q.qtype, pai, res); 2221 if (ai) 2222 cur->ai_next = ai; 2223 free(buf); 2224 free(buf2); 2225 if (sentinel.ai_next == NULL) 2226 switch (res->res_h_errno) { 2227 case HOST_NOT_FOUND: 2228 return NS_NOTFOUND; 2229 case TRY_AGAIN: 2230 return NS_TRYAGAIN; 2231 default: 2232 return NS_UNAVAIL; 2233 } 2234 *((struct addrinfo **)rv) = sentinel.ai_next; 2235 return NS_SUCCESS; 2236} 2237 2238static void 2239_sethtent(FILE **hostf) 2240{ 2241 if (!*hostf) 2242 *hostf = fopen(_PATH_HOSTS, "r"); 2243 else 2244 rewind(*hostf); 2245} 2246 2247static void 2248_endhtent(FILE **hostf) 2249{ 2250 if (*hostf) { 2251 (void) fclose(*hostf); 2252 *hostf = NULL; 2253 } 2254} 2255 2256static struct addrinfo * 2257_gethtent(FILE **hostf, const char *name, const struct addrinfo *pai) 2258{ 2259 char *p; 2260 char *cp, *tname, *cname; 2261 struct addrinfo hints, *res0, *res; 2262 int error; 2263 const char *addr; 2264 char hostbuf[8*1024]; 2265 2266 if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "r"))) 2267 return (NULL); 2268again: 2269 if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf))) 2270 return (NULL); 2271 if (*p == '#') 2272 goto again; 2273 cp = strpbrk(p, "#\n"); 2274 if (cp != NULL) 2275 *cp = '\0'; 2276 if (!(cp = strpbrk(p, " \t"))) 2277 goto again; 2278 *cp++ = '\0'; 2279 addr = p; 2280 cname = NULL; 2281 /* if this is not something we're looking for, skip it. */ 2282 while (cp && *cp) { 2283 if (*cp == ' ' || *cp == '\t') { 2284 cp++; 2285 continue; 2286 } 2287 tname = cp; 2288 if (cname == NULL) 2289 cname = cp; 2290 if ((cp = strpbrk(cp, " \t")) != NULL) 2291 *cp++ = '\0'; 2292 if (strcasecmp(name, tname) == 0) 2293 goto found; 2294 } 2295 goto again; 2296 2297found: 2298 /* we should not glob socktype/protocol here */ 2299 memset(&hints, 0, sizeof(hints)); 2300 hints.ai_family = pai->ai_family; 2301 hints.ai_socktype = SOCK_DGRAM; 2302 hints.ai_protocol = 0; 2303 hints.ai_flags = AI_NUMERICHOST; 2304 error = getaddrinfo(addr, "0", &hints, &res0); 2305 if (error) 2306 goto again; 2307#ifdef FILTER_V4MAPPED 2308 /* XXX should check all items in the chain */ 2309 if (res0->ai_family == AF_INET6 && 2310 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)res0->ai_addr)->sin6_addr)) { 2311 freeaddrinfo(res0); 2312 goto again; 2313 } 2314#endif 2315 for (res = res0; res; res = res->ai_next) { 2316 /* cover it up */ 2317 res->ai_flags = pai->ai_flags; 2318 res->ai_socktype = pai->ai_socktype; 2319 res->ai_protocol = pai->ai_protocol; 2320 2321 if (pai->ai_flags & AI_CANONNAME) { 2322 if (get_canonname(pai, res, cname) != 0) { 2323 freeaddrinfo(res0); 2324 goto again; 2325 } 2326 } 2327 } 2328 return res0; 2329} 2330 2331/*ARGSUSED*/ 2332static int 2333_files_getaddrinfo(void *rv, void *cb_data, va_list ap) 2334{ 2335 const char *name; 2336 const struct addrinfo *pai; 2337 struct addrinfo sentinel, *cur; 2338 struct addrinfo *p; 2339 FILE *hostf = NULL; 2340 2341 name = va_arg(ap, char *); 2342 pai = va_arg(ap, struct addrinfo *); 2343 2344 memset(&sentinel, 0, sizeof(sentinel)); 2345 cur = &sentinel; 2346 2347 _sethtent(&hostf); 2348 while ((p = _gethtent(&hostf, name, pai)) != NULL) { 2349 cur->ai_next = p; 2350 while (cur && cur->ai_next) 2351 cur = cur->ai_next; 2352 } 2353 _endhtent(&hostf); 2354 2355 *((struct addrinfo **)rv) = sentinel.ai_next; 2356 if (sentinel.ai_next == NULL) 2357 return NS_NOTFOUND; 2358 return NS_SUCCESS; 2359} 2360 2361#ifdef YP 2362/*ARGSUSED*/ 2363static struct addrinfo * 2364_yphostent(char *line, const struct addrinfo *pai) 2365{ 2366 struct addrinfo sentinel, *cur; 2367 struct addrinfo hints, *res, *res0; 2368 int error; 2369 char *p = line; 2370 const char *addr, *canonname; 2371 char *nextline; 2372 char *cp; 2373 2374 addr = canonname = NULL; 2375 2376 memset(&sentinel, 0, sizeof(sentinel)); 2377 cur = &sentinel; 2378 2379nextline: 2380 /* terminate line */ 2381 cp = strchr(p, '\n'); 2382 if (cp) { 2383 *cp++ = '\0'; 2384 nextline = cp; 2385 } else 2386 nextline = NULL; 2387 2388 cp = strpbrk(p, " \t"); 2389 if (cp == NULL) { 2390 if (canonname == NULL) 2391 return (NULL); 2392 else 2393 goto done; 2394 } 2395 *cp++ = '\0'; 2396 2397 addr = p; 2398 2399 while (cp && *cp) { 2400 if (*cp == ' ' || *cp == '\t') { 2401 cp++; 2402 continue; 2403 } 2404 if (!canonname) 2405 canonname = cp; 2406 if ((cp = strpbrk(cp, " \t")) != NULL) 2407 *cp++ = '\0'; 2408 } 2409 2410 hints = *pai; 2411 hints.ai_flags = AI_NUMERICHOST; 2412 error = getaddrinfo(addr, NULL, &hints, &res0); 2413 if (error == 0) { 2414 for (res = res0; res; res = res->ai_next) { 2415 /* cover it up */ 2416 res->ai_flags = pai->ai_flags; 2417 2418 if (pai->ai_flags & AI_CANONNAME) 2419 (void)get_canonname(pai, res, canonname); 2420 } 2421 } else 2422 res0 = NULL; 2423 if (res0) { 2424 cur->ai_next = res0; 2425 while (cur && cur->ai_next) 2426 cur = cur->ai_next; 2427 } 2428 2429 if (nextline) { 2430 p = nextline; 2431 goto nextline; 2432 } 2433 2434done: 2435 return sentinel.ai_next; 2436} 2437 2438/*ARGSUSED*/ 2439static int 2440_yp_getaddrinfo(void *rv, void *cb_data, va_list ap) 2441{ 2442 struct addrinfo sentinel, *cur; 2443 struct addrinfo *ai = NULL; 2444 char *ypbuf; 2445 int ypbuflen, r; 2446 const char *name; 2447 const struct addrinfo *pai; 2448 char *ypdomain; 2449 2450 if (_yp_check(&ypdomain) == 0) 2451 return NS_UNAVAIL; 2452 2453 name = va_arg(ap, char *); 2454 pai = va_arg(ap, const struct addrinfo *); 2455 2456 memset(&sentinel, 0, sizeof(sentinel)); 2457 cur = &sentinel; 2458 2459 /* hosts.byname is only for IPv4 (Solaris8) */ 2460 if (pai->ai_family == PF_UNSPEC || pai->ai_family == PF_INET) { 2461 r = yp_match(ypdomain, "hosts.byname", name, 2462 (int)strlen(name), &ypbuf, &ypbuflen); 2463 if (r == 0) { 2464 struct addrinfo ai4; 2465 2466 ai4 = *pai; 2467 ai4.ai_family = AF_INET; 2468 ai = _yphostent(ypbuf, &ai4); 2469 if (ai) { 2470 cur->ai_next = ai; 2471 while (cur && cur->ai_next) 2472 cur = cur->ai_next; 2473 } 2474 free(ypbuf); 2475 } 2476 } 2477 2478 /* ipnodes.byname can hold both IPv4/v6 */ 2479 r = yp_match(ypdomain, "ipnodes.byname", name, 2480 (int)strlen(name), &ypbuf, &ypbuflen); 2481 if (r == 0) { 2482 ai = _yphostent(ypbuf, pai); 2483 if (ai) 2484 cur->ai_next = ai; 2485 free(ypbuf); 2486 } 2487 2488 if (sentinel.ai_next == NULL) { 2489 RES_SET_H_ERRNO(__res_state(), HOST_NOT_FOUND); 2490 return NS_NOTFOUND; 2491 } 2492 *((struct addrinfo **)rv) = sentinel.ai_next; 2493 return NS_SUCCESS; 2494} 2495#endif 2496 2497/* resolver logic */ 2498 2499/* 2500 * Formulate a normal query, send, and await answer. 2501 * Returned answer is placed in supplied buffer "answer". 2502 * Perform preliminary check of answer, returning success only 2503 * if no error is indicated and the answer count is nonzero. 2504 * Return the size of the response on success, -1 on error. 2505 * Error number is left in h_errno. 2506 * 2507 * Caller must parse answer and determine whether it answers the question. 2508 */ 2509static int 2510res_queryN(const char *name, struct res_target *target, res_state res) 2511{ 2512 u_char *buf; 2513 HEADER *hp; 2514 int n; 2515 u_int oflags; 2516 struct res_target *t; 2517 int rcode; 2518 int ancount; 2519 2520 rcode = NOERROR; 2521 ancount = 0; 2522 2523 buf = malloc(MAXPACKET); 2524 if (!buf) { 2525 RES_SET_H_ERRNO(res, NETDB_INTERNAL); 2526 return -1; 2527 } 2528 2529 for (t = target; t; t = t->next) { 2530 int class, type; 2531 u_char *answer; 2532 int anslen; 2533 2534 hp = (HEADER *)(void *)t->answer; 2535 2536 /* make it easier... */ 2537 class = t->qclass; 2538 type = t->qtype; 2539 answer = t->answer; 2540 anslen = t->anslen; 2541 2542 oflags = res->_flags; 2543 2544again: 2545 hp->rcode = NOERROR; /* default */ 2546 2547#ifdef DEBUG 2548 if (res->options & RES_DEBUG) 2549 printf(";; res_query(%s, %d, %d)\n", name, class, type); 2550#endif 2551 2552 n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL, 2553 buf, MAXPACKET); 2554 if (n > 0 && (res->_flags & RES_F_EDNS0ERR) == 0 && 2555 (res->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0U) 2556 n = res_nopt(res, n, buf, MAXPACKET, anslen); 2557 if (n <= 0) { 2558#ifdef DEBUG 2559 if (res->options & RES_DEBUG) 2560 printf(";; res_query: mkquery failed\n"); 2561#endif 2562 free(buf); 2563 RES_SET_H_ERRNO(res, NO_RECOVERY); 2564 return (n); 2565 } 2566 n = res_nsend(res, buf, n, answer, anslen); 2567 if (n < 0) { 2568 /* 2569 * if the query choked with EDNS0, retry 2570 * without EDNS0 2571 */ 2572 if ((res->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) 2573 != 0U && 2574 ((oflags ^ res->_flags) & RES_F_EDNS0ERR) != 0) { 2575 res->_flags |= RES_F_EDNS0ERR; 2576 if (res->options & RES_DEBUG) 2577 printf(";; res_nquery: retry without EDNS0\n"); 2578 goto again; 2579 } 2580 rcode = hp->rcode; /* record most recent error */ 2581#ifdef DEBUG 2582 if (res->options & RES_DEBUG) 2583 printf(";; res_query: send error\n"); 2584#endif 2585 continue; 2586 } 2587 2588 if (n > anslen) 2589 hp->rcode = FORMERR; /* XXX not very informative */ 2590 if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) { 2591 rcode = hp->rcode; /* record most recent error */ 2592#ifdef DEBUG 2593 if (res->options & RES_DEBUG) 2594 printf(";; rcode = %u, ancount=%u\n", hp->rcode, 2595 ntohs(hp->ancount)); 2596#endif 2597 continue; 2598 } 2599 2600 ancount += ntohs(hp->ancount); 2601 2602 t->n = n; 2603 } 2604 2605 free(buf); 2606 2607 if (ancount == 0) { 2608 switch (rcode) { 2609 case NXDOMAIN: 2610 RES_SET_H_ERRNO(res, HOST_NOT_FOUND); 2611 break; 2612 case SERVFAIL: 2613 RES_SET_H_ERRNO(res, TRY_AGAIN); 2614 break; 2615 case NOERROR: 2616 RES_SET_H_ERRNO(res, NO_DATA); 2617 break; 2618 case FORMERR: 2619 case NOTIMP: 2620 case REFUSED: 2621 default: 2622 RES_SET_H_ERRNO(res, NO_RECOVERY); 2623 break; 2624 } 2625 return (-1); 2626 } 2627 return (ancount); 2628} 2629 2630/* 2631 * Formulate a normal query, send, and retrieve answer in supplied buffer. 2632 * Return the size of the response on success, -1 on error. 2633 * If enabled, implement search rules until answer or unrecoverable failure 2634 * is detected. Error code, if any, is left in h_errno. 2635 */ 2636static int 2637res_searchN(const char *name, struct res_target *target, res_state res) 2638{ 2639 const char *cp, * const *domain; 2640 HEADER *hp = (HEADER *)(void *)target->answer; /*XXX*/ 2641 u_int dots; 2642 int trailing_dot, ret, saved_herrno; 2643 int got_nodata = 0, got_servfail = 0, root_on_list = 0; 2644 int tried_as_is = 0; 2645 int searched = 0; 2646 char abuf[MAXDNAME]; 2647 2648 errno = 0; 2649 RES_SET_H_ERRNO(res, HOST_NOT_FOUND); /* default, if we never query */ 2650 dots = 0; 2651 for (cp = name; *cp; cp++) 2652 dots += (*cp == '.'); 2653 trailing_dot = 0; 2654 if (cp > name && *--cp == '.') 2655 trailing_dot++; 2656 2657 /* 2658 * if there aren't any dots, it could be a user-level alias 2659 */ 2660 if (!dots && 2661 (cp = res_hostalias(res, name, abuf, sizeof(abuf))) != NULL) 2662 return (res_queryN(cp, target, res)); 2663 2664 /* 2665 * If there are enough dots in the name, let's just give it a 2666 * try 'as is'. The threshold can be set with the "ndots" option. 2667 * Also, query 'as is', if there is a trailing dot in the name. 2668 */ 2669 saved_herrno = -1; 2670 if (dots >= res->ndots || trailing_dot) { 2671 ret = res_querydomainN(name, NULL, target, res); 2672 if (ret > 0 || trailing_dot) 2673 return (ret); 2674 if (errno == ECONNREFUSED) { 2675 RES_SET_H_ERRNO(res, TRY_AGAIN); 2676 return (-1); 2677 } 2678 switch (res->res_h_errno) { 2679 case NO_DATA: 2680 case HOST_NOT_FOUND: 2681 break; 2682 case TRY_AGAIN: 2683 if (hp->rcode == SERVFAIL) 2684 break; 2685 /* FALLTHROUGH */ 2686 default: 2687 return (-1); 2688 } 2689 saved_herrno = res->res_h_errno; 2690 tried_as_is++; 2691 } 2692 2693 /* 2694 * We do at least one level of search if 2695 * - there is no dot and RES_DEFNAME is set, or 2696 * - there is at least one dot, there is no trailing dot, 2697 * and RES_DNSRCH is set. 2698 */ 2699 if ((!dots && (res->options & RES_DEFNAMES)) || 2700 (dots && !trailing_dot && (res->options & RES_DNSRCH))) { 2701 int done = 0; 2702 2703 for (domain = (const char * const *)res->dnsrch; 2704 *domain && !done; 2705 domain++) { 2706 searched = 1; 2707 2708 if (domain[0][0] == '\0' || 2709 (domain[0][0] == '.' && domain[0][1] == '\0')) 2710 root_on_list++; 2711 2712 if (root_on_list && tried_as_is) 2713 continue; 2714 2715 ret = res_querydomainN(name, *domain, target, res); 2716 if (ret > 0) 2717 return (ret); 2718 2719 /* 2720 * If no server present, give up. 2721 * If name isn't found in this domain, 2722 * keep trying higher domains in the search list 2723 * (if that's enabled). 2724 * On a NO_DATA error, keep trying, otherwise 2725 * a wildcard entry of another type could keep us 2726 * from finding this entry higher in the domain. 2727 * If we get some other error (negative answer or 2728 * server failure), then stop searching up, 2729 * but try the input name below in case it's 2730 * fully-qualified. 2731 */ 2732 if (errno == ECONNREFUSED) { 2733 RES_SET_H_ERRNO(res, TRY_AGAIN); 2734 return (-1); 2735 } 2736 2737 switch (res->res_h_errno) { 2738 case NO_DATA: 2739 got_nodata++; 2740 /* FALLTHROUGH */ 2741 case HOST_NOT_FOUND: 2742 /* keep trying */ 2743 break; 2744 case TRY_AGAIN: 2745 got_servfail++; 2746 if (hp->rcode == SERVFAIL) { 2747 /* try next search element, if any */ 2748 break; 2749 } 2750 /* FALLTHROUGH */ 2751 default: 2752 /* anything else implies that we're done */ 2753 done++; 2754 } 2755 /* 2756 * if we got here for some reason other than DNSRCH, 2757 * we only wanted one iteration of the loop, so stop. 2758 */ 2759 if (!(res->options & RES_DNSRCH)) 2760 done++; 2761 } 2762 } 2763 2764 switch (res->res_h_errno) { 2765 case NO_DATA: 2766 case HOST_NOT_FOUND: 2767 break; 2768 case TRY_AGAIN: 2769 if (hp->rcode == SERVFAIL) 2770 break; 2771 /* FALLTHROUGH */ 2772 default: 2773 goto giveup; 2774 } 2775 2776 /* 2777 * If the query has not already been tried as is then try it 2778 * unless RES_NOTLDQUERY is set and there were no dots. 2779 */ 2780 if ((dots || !searched || !(res->options & RES_NOTLDQUERY)) && 2781 !(tried_as_is || root_on_list)) { 2782 ret = res_querydomainN(name, NULL, target, res); 2783 if (ret > 0) 2784 return (ret); 2785 } 2786 2787 /* 2788 * if we got here, we didn't satisfy the search. 2789 * if we did an initial full query, return that query's h_errno 2790 * (note that we wouldn't be here if that query had succeeded). 2791 * else if we ever got a nodata, send that back as the reason. 2792 * else send back meaningless h_errno, that being the one from 2793 * the last DNSRCH we did. 2794 */ 2795giveup: 2796 if (saved_herrno != -1) 2797 RES_SET_H_ERRNO(res, saved_herrno); 2798 else if (got_nodata) 2799 RES_SET_H_ERRNO(res, NO_DATA); 2800 else if (got_servfail) 2801 RES_SET_H_ERRNO(res, TRY_AGAIN); 2802 return (-1); 2803} 2804 2805/* 2806 * Perform a call on res_query on the concatenation of name and domain, 2807 * removing a trailing dot from name if domain is NULL. 2808 */ 2809static int 2810res_querydomainN(const char *name, const char *domain, 2811 struct res_target *target, res_state res) 2812{ 2813 char nbuf[MAXDNAME]; 2814 const char *longname = nbuf; 2815 size_t n, d; 2816 2817#ifdef DEBUG 2818 if (res->options & RES_DEBUG) 2819 printf(";; res_querydomain(%s, %s)\n", 2820 name, domain?domain:"<Nil>"); 2821#endif 2822 if (domain == NULL) { 2823 /* 2824 * Check for trailing '.'; 2825 * copy without '.' if present. 2826 */ 2827 n = strlen(name); 2828 if (n >= MAXDNAME) { 2829 RES_SET_H_ERRNO(res, NO_RECOVERY); 2830 return (-1); 2831 } 2832 if (n > 0 && name[--n] == '.') { 2833 strncpy(nbuf, name, n); 2834 nbuf[n] = '\0'; 2835 } else 2836 longname = name; 2837 } else { 2838 n = strlen(name); 2839 d = strlen(domain); 2840 if (n + d + 1 >= MAXDNAME) { 2841 RES_SET_H_ERRNO(res, NO_RECOVERY); 2842 return (-1); 2843 } 2844 snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain); 2845 } 2846 return (res_queryN(longname, target, res)); 2847} 2848