res_send.c revision 267654
11573Srgrimes/* 2239589Spfg * Copyright (c) 1985, 1989, 1993 384260Sobrien * The Regents of the University of California. All rights reserved. 41573Srgrimes * 51573Srgrimes * Redistribution and use in source and binary forms, with or without 61573Srgrimes * modification, are permitted provided that the following conditions 71573Srgrimes * are met: 81573Srgrimes * 1. Redistributions of source code must retain the above copyright 91573Srgrimes * notice, this list of conditions and the following disclaimer. 101573Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 111573Srgrimes * notice, this list of conditions and the following disclaimer in the 121573Srgrimes * documentation and/or other materials provided with the distribution. 131573Srgrimes * 4. Neither the name of the University nor the names of its contributors 141573Srgrimes * may be used to endorse or promote products derived from this software 151573Srgrimes * without specific prior written permission. 161573Srgrimes * 171573Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 181573Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19148834Sstefanf * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 201573Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 211573Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 221573Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 231573Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 241573Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 251573Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 261573Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 271573Srgrimes * SUCH DAMAGE. 281573Srgrimes */ 291573Srgrimes 301573Srgrimes/* 311573Srgrimes * Portions Copyright (c) 1993 by Digital Equipment Corporation. 321573Srgrimes * 331573Srgrimes * Permission to use, copy, modify, and distribute this software for any 341573Srgrimes * purpose with or without fee is hereby granted, provided that the above 351573Srgrimes * copyright notice and this permission notice appear in all copies, and that 361573Srgrimes * the name of Digital Equipment Corporation not be used in advertising or 371573Srgrimes * publicity pertaining to distribution of the document or software without 381573Srgrimes * specific, written prior permission. 39148834Sstefanf * 4095258Sdes * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 411573Srgrimes * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 421573Srgrimes * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 431573Srgrimes * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 441573Srgrimes * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 451573Srgrimes * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 461573Srgrimes * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 471573Srgrimes * SOFTWARE. 481573Srgrimes */ 491573Srgrimes 501573Srgrimes/* 511573Srgrimes * Copyright (c) 2005 by Internet Systems Consortium, Inc. ("ISC") 521573Srgrimes * Portions Copyright (c) 1996-1999 by Internet Software Consortium. 531573Srgrimes * 5484260Sobrien * Permission to use, copy, modify, and distribute this software for any 5584260Sobrien * purpose with or without fee is hereby granted, provided that the above 5684260Sobrien * copyright notice and this permission notice appear in all copies. 571573Srgrimes * 5884260Sobrien * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 5984260Sobrien * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 601573Srgrimes * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 611573Srgrimes * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 621573Srgrimes * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 631573Srgrimes * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 641573Srgrimes * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 651573Srgrimes */ 661573Srgrimes 671573Srgrimes#if defined(LIBC_SCCS) && !defined(lint) 681573Srgrimesstatic const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93"; 6984260Sobrienstatic const char rcsid[] = "$Id: res_send.c,v 1.9.18.10 2008/01/27 02:06:26 marka Exp $"; 7084260Sobrien#endif /* LIBC_SCCS and not lint */ 7184260Sobrien#include <sys/cdefs.h> 7284260Sobrien__FBSDID("$FreeBSD: releng/9.3/lib/libc/resolv/res_send.c 229077 2011-12-31 12:45:43Z dim $"); 7384260Sobrien 741573Srgrimes/*! \file 751573Srgrimes * \brief 761573Srgrimes * Send query to name server and wait for reply. 771573Srgrimes */ 7884260Sobrien 7984260Sobrien#include "port_before.h" 8084260Sobrien#ifndef USE_KQUEUE 8184260Sobrien#include "fd_setsize.h" 8284260Sobrien#endif 831573Srgrimes 841573Srgrimes#include "namespace.h" 851573Srgrimes#include <sys/types.h> 861573Srgrimes#include <sys/param.h> 871573Srgrimes#include <sys/time.h> 8884260Sobrien#include <sys/socket.h> 891573Srgrimes#include <sys/uio.h> 901573Srgrimes 911573Srgrimes#include <netinet/in.h> 921573Srgrimes#include <arpa/nameser.h> 931573Srgrimes#include <arpa/inet.h> 941573Srgrimes 951573Srgrimes#include <errno.h> 961573Srgrimes#include <netdb.h> 971573Srgrimes#include <resolv.h> 981573Srgrimes#include <signal.h> 991573Srgrimes#include <stdio.h> 1001573Srgrimes#include <stdlib.h> 1011573Srgrimes#include <string.h> 1021573Srgrimes#include <unistd.h> 1031573Srgrimes 1041573Srgrimes#include <isc/eventlib.h> 1051573Srgrimes 1061573Srgrimes#include "port_after.h" 10784260Sobrien 1081573Srgrimes#ifdef USE_KQUEUE 10984260Sobrien#include <sys/event.h> 1101573Srgrimes#else 1111573Srgrimes#ifdef USE_POLL 1121573Srgrimes#ifdef HAVE_STROPTS_H 1131573Srgrimes#include <stropts.h> 1141573Srgrimes#endif 1151573Srgrimes#include <poll.h> 1161573Srgrimes#endif /* USE_POLL */ 1171573Srgrimes#endif 1181573Srgrimes 1191573Srgrimes#include "un-namespace.h" 1201573Srgrimes 1211573Srgrimes/* Options. Leave them on. */ 1221573Srgrimes#define DEBUG 12384260Sobrien#include "res_debug.h" 1241573Srgrimes#include "res_private.h" 12584260Sobrien 12684260Sobrien#define EXT(res) ((res)->_u._ext) 12784260Sobrien 12884260Sobrien#if !defined(USE_POLL) && !defined(USE_KQUEUE) 12984260Sobrienstatic const int highestFD = FD_SETSIZE - 1; 1301573Srgrimes#endif 1311573Srgrimes 13284260Sobrien/* Forward. */ 1331573Srgrimes 1341573Srgrimesstatic int get_salen(const struct sockaddr *); 13584260Sobrienstatic struct sockaddr * get_nsaddr(res_state, size_t); 1361573Srgrimesstatic int send_vc(res_state, const u_char *, int, 13784260Sobrien u_char *, int, int *, int); 13884260Sobrienstatic int send_dg(res_state, 13984260Sobrien#ifdef USE_KQUEUE 14084260Sobrien int kq, 14184260Sobrien#endif 1421573Srgrimes const u_char *, int, 1431573Srgrimes u_char *, int, int *, int, int, 144239589Spfg int *, int *); 14584260Sobrienstatic void Aerror(const res_state, FILE *, const char *, int, 1461573Srgrimes const struct sockaddr *, int); 1471573Srgrimesstatic void Perror(const res_state, FILE *, const char *, int); 14884260Sobrienstatic int sock_eq(struct sockaddr *, struct sockaddr *); 1491573Srgrimes#if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE) 15084260Sobrienstatic int pselect(int, void *, void *, void *, 1511573Srgrimes struct timespec *, 1521573Srgrimes const sigset_t *); 1531573Srgrimes#endif 1541573Srgrimesvoid res_pquery(const res_state, const u_char *, int, FILE *); 1551573Srgrimes 15684260Sobrienstatic const int niflags = NI_NUMERICHOST | NI_NUMERICSERV; 15784260Sobrien 1581573Srgrimes/* Public. */ 15984260Sobrien 16084260Sobrien/*% 16184260Sobrien * looks up "ina" in _res.ns_addr_list[] 16284260Sobrien * 16384260Sobrien * returns: 1641573Srgrimes *\li 0 : not found 1651573Srgrimes *\li >0 : found 1661573Srgrimes * 1671573Srgrimes * author: 1681573Srgrimes *\li paul vixie, 29may94 16984260Sobrien */ 1701573Srgrimesint 1711573Srgrimesres_ourserver_p(const res_state statp, const struct sockaddr *sa) { 1721573Srgrimes const struct sockaddr_in *inp, *srv; 1731573Srgrimes const struct sockaddr_in6 *in6p, *srv6; 1741573Srgrimes int ns; 1751573Srgrimes 1761573Srgrimes switch (sa->sa_family) { 17784260Sobrien case AF_INET: 1781573Srgrimes inp = (const struct sockaddr_in *)sa; 1791573Srgrimes for (ns = 0; ns < statp->nscount; ns++) { 1801573Srgrimes srv = (struct sockaddr_in *)get_nsaddr(statp, ns); 1811573Srgrimes if (srv->sin_family == inp->sin_family && 1821573Srgrimes srv->sin_port == inp->sin_port && 1831573Srgrimes (srv->sin_addr.s_addr == INADDR_ANY || 1841573Srgrimes srv->sin_addr.s_addr == inp->sin_addr.s_addr)) 1851573Srgrimes return (1); 1861573Srgrimes } 1871573Srgrimes break; 1881573Srgrimes case AF_INET6: 18984260Sobrien if (EXT(statp).ext == NULL) 19084260Sobrien break; 19184260Sobrien in6p = (const struct sockaddr_in6 *)sa; 19284260Sobrien for (ns = 0; ns < statp->nscount; ns++) { 19384260Sobrien srv6 = (struct sockaddr_in6 *)get_nsaddr(statp, ns); 19484260Sobrien if (srv6->sin6_family == in6p->sin6_family && 1951573Srgrimes srv6->sin6_port == in6p->sin6_port && 1961573Srgrimes#ifdef HAVE_SIN6_SCOPE_ID 1971573Srgrimes (srv6->sin6_scope_id == 0 || 1981573Srgrimes srv6->sin6_scope_id == in6p->sin6_scope_id) && 1991573Srgrimes#endif 2001573Srgrimes (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) || 2011573Srgrimes IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr))) 2021573Srgrimes return (1); 2031573Srgrimes } 20484260Sobrien break; 20584260Sobrien default: 20684260Sobrien break; 20784260Sobrien } 20884260Sobrien return (0); 20984260Sobrien} 21084260Sobrien 21184260Sobrien/*% 21284260Sobrien * look for (name,type,class) in the query section of packet (buf,eom) 21384260Sobrien * 21484260Sobrien * requires: 21584260Sobrien *\li buf + HFIXEDSZ <= eom 21684260Sobrien * 21784260Sobrien * returns: 21884260Sobrien *\li -1 : format error 21984260Sobrien *\li 0 : not found 22084260Sobrien *\li >0 : found 22184260Sobrien * 22284260Sobrien * author: 22384260Sobrien *\li paul vixie, 29may94 22484260Sobrien */ 22584260Sobrienint 22684260Sobrienres_nameinquery(const char *name, int type, int class, 22784260Sobrien const u_char *buf, const u_char *eom) 22884260Sobrien{ 22984260Sobrien const u_char *cp = buf + HFIXEDSZ; 23084260Sobrien int qdcount = ntohs(((const HEADER*)buf)->qdcount); 23184260Sobrien 23284260Sobrien while (qdcount-- > 0) { 23384260Sobrien char tname[MAXDNAME+1]; 23484260Sobrien int n, ttype, tclass; 23584260Sobrien 23684260Sobrien n = dn_expand(buf, eom, cp, tname, sizeof tname); 23784260Sobrien if (n < 0) 23884260Sobrien return (-1); 23984260Sobrien cp += n; 24084260Sobrien if (cp + 2 * INT16SZ > eom) 24184260Sobrien return (-1); 24284260Sobrien ttype = ns_get16(cp); cp += INT16SZ; 24384260Sobrien tclass = ns_get16(cp); cp += INT16SZ; 24484260Sobrien if (ttype == type && tclass == class && 2451573Srgrimes ns_samename(tname, name) == 1) 2461573Srgrimes return (1); 24784260Sobrien } 24884260Sobrien return (0); 24984260Sobrien} 2501573Srgrimes 251/*% 252 * is there a 1:1 mapping of (name,type,class) 253 * in (buf1,eom1) and (buf2,eom2)? 254 * 255 * returns: 256 *\li -1 : format error 257 *\li 0 : not a 1:1 mapping 258 *\li >0 : is a 1:1 mapping 259 * 260 * author: 261 *\li paul vixie, 29may94 262 */ 263int 264res_queriesmatch(const u_char *buf1, const u_char *eom1, 265 const u_char *buf2, const u_char *eom2) 266{ 267 const u_char *cp = buf1 + HFIXEDSZ; 268 int qdcount = ntohs(((const HEADER*)buf1)->qdcount); 269 270 if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2) 271 return (-1); 272 273 /* 274 * Only header section present in replies to 275 * dynamic update packets. 276 */ 277 if ((((const HEADER *)buf1)->opcode == ns_o_update) && 278 (((const HEADER *)buf2)->opcode == ns_o_update)) 279 return (1); 280 281 if (qdcount != ntohs(((const HEADER*)buf2)->qdcount)) 282 return (0); 283 while (qdcount-- > 0) { 284 char tname[MAXDNAME+1]; 285 int n, ttype, tclass; 286 287 n = dn_expand(buf1, eom1, cp, tname, sizeof tname); 288 if (n < 0) 289 return (-1); 290 cp += n; 291 if (cp + 2 * INT16SZ > eom1) 292 return (-1); 293 ttype = ns_get16(cp); cp += INT16SZ; 294 tclass = ns_get16(cp); cp += INT16SZ; 295 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) 296 return (0); 297 } 298 return (1); 299} 300 301int 302res_nsend(res_state statp, 303 const u_char *buf, int buflen, u_char *ans, int anssiz) 304{ 305 int gotsomewhere, terrno, tries, v_circuit, resplen, ns, n; 306#ifdef USE_KQUEUE 307 int kq; 308#endif 309 char abuf[NI_MAXHOST]; 310 311 /* No name servers or res_init() failure */ 312 if (statp->nscount == 0 || EXT(statp).ext == NULL) { 313 errno = ESRCH; 314 return (-1); 315 } 316 if (anssiz < HFIXEDSZ) { 317 errno = EINVAL; 318 return (-1); 319 } 320 DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY), 321 (stdout, ";; res_send()\n"), buf, buflen); 322 v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ; 323 gotsomewhere = 0; 324 terrno = ETIMEDOUT; 325 326#ifdef USE_KQUEUE 327 if ((kq = kqueue()) < 0) { 328 Perror(statp, stderr, "kqueue", errno); 329 return (-1); 330 } 331#endif 332 333 /* 334 * If the ns_addr_list in the resolver context has changed, then 335 * invalidate our cached copy and the associated timing data. 336 */ 337 if (EXT(statp).nscount != 0) { 338 int needclose = 0; 339 struct sockaddr_storage peer; 340 ISC_SOCKLEN_T peerlen; 341 342 if (EXT(statp).nscount != statp->nscount) 343 needclose++; 344 else 345 for (ns = 0; ns < statp->nscount; ns++) { 346 if (statp->nsaddr_list[ns].sin_family && 347 !sock_eq((struct sockaddr *)&statp->nsaddr_list[ns], 348 (struct sockaddr *)&EXT(statp).ext->nsaddrs[ns])) { 349 needclose++; 350 break; 351 } 352 353 if (EXT(statp).nssocks[ns] == -1) 354 continue; 355 peerlen = sizeof(peer); 356 if (_getsockname(EXT(statp).nssocks[ns], 357 (struct sockaddr *)&peer, &peerlen) < 0) { 358 needclose++; 359 break; 360 } 361 if (!sock_eq((struct sockaddr *)&peer, 362 get_nsaddr(statp, ns))) { 363 needclose++; 364 break; 365 } 366 } 367 if (needclose) { 368 res_nclose(statp); 369 EXT(statp).nscount = 0; 370 } 371 } 372 373 /* 374 * Maybe initialize our private copy of the ns_addr_list. 375 */ 376 if (EXT(statp).nscount == 0) { 377 for (ns = 0; ns < statp->nscount; ns++) { 378 EXT(statp).nstimes[ns] = RES_MAXTIME; 379 EXT(statp).nssocks[ns] = -1; 380 if (!statp->nsaddr_list[ns].sin_family) 381 continue; 382 EXT(statp).ext->nsaddrs[ns].sin = 383 statp->nsaddr_list[ns]; 384 } 385 EXT(statp).nscount = statp->nscount; 386 } 387 388 /* 389 * Some resolvers want to even out the load on their nameservers. 390 * Note that RES_BLAST overrides RES_ROTATE. 391 */ 392 if ((statp->options & RES_ROTATE) != 0U && 393 (statp->options & RES_BLAST) == 0U) { 394 union res_sockaddr_union inu; 395 struct sockaddr_in ina; 396 int lastns = statp->nscount - 1; 397 int fd; 398 u_int16_t nstime; 399 400 if (EXT(statp).ext != NULL) 401 inu = EXT(statp).ext->nsaddrs[0]; 402 ina = statp->nsaddr_list[0]; 403 fd = EXT(statp).nssocks[0]; 404 nstime = EXT(statp).nstimes[0]; 405 for (ns = 0; ns < lastns; ns++) { 406 if (EXT(statp).ext != NULL) 407 EXT(statp).ext->nsaddrs[ns] = 408 EXT(statp).ext->nsaddrs[ns + 1]; 409 statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1]; 410 EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1]; 411 EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1]; 412 } 413 if (EXT(statp).ext != NULL) 414 EXT(statp).ext->nsaddrs[lastns] = inu; 415 statp->nsaddr_list[lastns] = ina; 416 EXT(statp).nssocks[lastns] = fd; 417 EXT(statp).nstimes[lastns] = nstime; 418 } 419 420 /* 421 * Send request, RETRY times, or until successful. 422 */ 423 for (tries = 0; tries < statp->retry; tries++) { 424 for (ns = 0; ns < statp->nscount; ns++) { 425 struct sockaddr *nsap; 426 int nsaplen; 427 nsap = get_nsaddr(statp, ns); 428 nsaplen = get_salen(nsap); 429 statp->_flags &= ~RES_F_LASTMASK; 430 statp->_flags |= (ns << RES_F_LASTSHIFT); 431 same_ns: 432 if (statp->qhook) { 433 int done = 0, loops = 0; 434 435 do { 436 res_sendhookact act; 437 438 act = (*statp->qhook)(&nsap, &buf, &buflen, 439 ans, anssiz, &resplen); 440 switch (act) { 441 case res_goahead: 442 done = 1; 443 break; 444 case res_nextns: 445 res_nclose(statp); 446 goto next_ns; 447 case res_done: 448#ifdef USE_KQUEUE 449 _close(kq); 450#endif 451 return (resplen); 452 case res_modified: 453 /* give the hook another try */ 454 if (++loops < 42) /*doug adams*/ 455 break; 456 /*FALLTHROUGH*/ 457 case res_error: 458 /*FALLTHROUGH*/ 459 default: 460 goto fail; 461 } 462 } while (!done); 463 } 464 465 Dprint(((statp->options & RES_DEBUG) && 466 getnameinfo(nsap, nsaplen, abuf, sizeof(abuf), 467 NULL, 0, niflags) == 0), 468 (stdout, ";; Querying server (# %d) address = %s\n", 469 ns + 1, abuf)); 470 471 472 if (v_circuit) { 473 /* Use VC; at most one attempt per server. */ 474 tries = statp->retry; 475 n = send_vc(statp, buf, buflen, ans, anssiz, &terrno, 476 ns); 477 if (n < 0) 478 goto fail; 479 if (n == 0) 480 goto next_ns; 481 resplen = n; 482 } else { 483 /* Use datagrams. */ 484 n = send_dg(statp, 485#ifdef USE_KQUEUE 486 kq, 487#endif 488 buf, buflen, ans, anssiz, &terrno, 489 ns, tries, &v_circuit, &gotsomewhere); 490 if (n < 0) 491 goto fail; 492 if (n == 0) 493 goto next_ns; 494 if (v_circuit) 495 goto same_ns; 496 resplen = n; 497 } 498 499 Dprint((statp->options & RES_DEBUG) || 500 ((statp->pfcode & RES_PRF_REPLY) && 501 (statp->pfcode & RES_PRF_HEAD1)), 502 (stdout, ";; got answer:\n")); 503 504 DprintQ((statp->options & RES_DEBUG) || 505 (statp->pfcode & RES_PRF_REPLY), 506 (stdout, "%s", ""), 507 ans, (resplen > anssiz) ? anssiz : resplen); 508 509 /* 510 * If we have temporarily opened a virtual circuit, 511 * or if we haven't been asked to keep a socket open, 512 * close the socket. 513 */ 514 if ((v_circuit && (statp->options & RES_USEVC) == 0U) || 515 (statp->options & RES_STAYOPEN) == 0U) { 516 res_nclose(statp); 517 } 518 if (statp->rhook) { 519 int done = 0, loops = 0; 520 521 do { 522 res_sendhookact act; 523 524 act = (*statp->rhook)(nsap, buf, buflen, 525 ans, anssiz, &resplen); 526 switch (act) { 527 case res_goahead: 528 case res_done: 529 done = 1; 530 break; 531 case res_nextns: 532 res_nclose(statp); 533 goto next_ns; 534 case res_modified: 535 /* give the hook another try */ 536 if (++loops < 42) /*doug adams*/ 537 break; 538 /*FALLTHROUGH*/ 539 case res_error: 540 /*FALLTHROUGH*/ 541 default: 542 goto fail; 543 } 544 } while (!done); 545 546 } 547#ifdef USE_KQUEUE 548 _close(kq); 549#endif 550 return (resplen); 551 next_ns: ; 552 } /*foreach ns*/ 553 } /*foreach retry*/ 554 res_nclose(statp); 555#ifdef USE_KQUEUE 556 _close(kq); 557#endif 558 if (!v_circuit) { 559 if (!gotsomewhere) 560 errno = ECONNREFUSED; /*%< no nameservers found */ 561 else 562 errno = ETIMEDOUT; /*%< no answer obtained */ 563 } else 564 errno = terrno; 565 return (-1); 566 fail: 567 res_nclose(statp); 568#ifdef USE_KQUEUE 569 _close(kq); 570#endif 571 return (-1); 572} 573 574/* Private */ 575 576static int 577get_salen(sa) 578 const struct sockaddr *sa; 579{ 580 581#ifdef HAVE_SA_LEN 582 /* There are people do not set sa_len. Be forgiving to them. */ 583 if (sa->sa_len) 584 return (sa->sa_len); 585#endif 586 587 if (sa->sa_family == AF_INET) 588 return (sizeof(struct sockaddr_in)); 589 else if (sa->sa_family == AF_INET6) 590 return (sizeof(struct sockaddr_in6)); 591 else 592 return (0); /*%< unknown, die on connect */ 593} 594 595/*% 596 * pick appropriate nsaddr_list for use. see res_init() for initialization. 597 */ 598static struct sockaddr * 599get_nsaddr(statp, n) 600 res_state statp; 601 size_t n; 602{ 603 604 if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) { 605 /* 606 * - EXT(statp).ext->nsaddrs[n] holds an address that is larger 607 * than struct sockaddr, and 608 * - user code did not update statp->nsaddr_list[n]. 609 */ 610 return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n]; 611 } else { 612 /* 613 * - user code updated statp->nsaddr_list[n], or 614 * - statp->nsaddr_list[n] has the same content as 615 * EXT(statp).ext->nsaddrs[n]. 616 */ 617 return (struct sockaddr *)(void *)&statp->nsaddr_list[n]; 618 } 619} 620 621static int 622send_vc(res_state statp, 623 const u_char *buf, int buflen, u_char *ans, int anssiz, 624 int *terrno, int ns) 625{ 626 const HEADER *hp = (const HEADER *) buf; 627 HEADER *anhp = (HEADER *) ans; 628 struct sockaddr *nsap; 629 int nsaplen; 630 int truncating, connreset, resplen, n; 631 struct iovec iov[2]; 632 u_short len; 633 u_char *cp; 634 void *tmp; 635#ifdef SO_NOSIGPIPE 636 int on = 1; 637#endif 638 639 nsap = get_nsaddr(statp, ns); 640 nsaplen = get_salen(nsap); 641 642 connreset = 0; 643 same_ns: 644 truncating = 0; 645 646 /* Are we still talking to whom we want to talk to? */ 647 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) { 648 struct sockaddr_storage peer; 649 ISC_SOCKLEN_T size = sizeof peer; 650 651 if (_getpeername(statp->_vcsock, 652 (struct sockaddr *)&peer, &size) < 0 || 653 !sock_eq((struct sockaddr *)&peer, nsap)) { 654 res_nclose(statp); 655 statp->_flags &= ~RES_F_VC; 656 } 657 } 658 659 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) { 660 if (statp->_vcsock >= 0) 661 res_nclose(statp); 662 663 statp->_vcsock = _socket(nsap->sa_family, SOCK_STREAM, 0); 664#if !defined(USE_POLL) && !defined(USE_KQUEUE) 665 if (statp->_vcsock > highestFD) { 666 res_nclose(statp); 667 errno = ENOTSOCK; 668 } 669#endif 670 if (statp->_vcsock < 0) { 671 switch (errno) { 672 case EPROTONOSUPPORT: 673#ifdef EPFNOSUPPORT 674 case EPFNOSUPPORT: 675#endif 676 case EAFNOSUPPORT: 677 Perror(statp, stderr, "socket(vc)", errno); 678 return (0); 679 default: 680 *terrno = errno; 681 Perror(statp, stderr, "socket(vc)", errno); 682 return (-1); 683 } 684 } 685#ifdef SO_NOSIGPIPE 686 /* 687 * Disable generation of SIGPIPE when writing to a closed 688 * socket. Write should return -1 and set errno to EPIPE 689 * instead. 690 * 691 * Push on even if setsockopt(SO_NOSIGPIPE) fails. 692 */ 693 (void)_setsockopt(statp->_vcsock, SOL_SOCKET, SO_NOSIGPIPE, &on, 694 sizeof(on)); 695#endif 696 errno = 0; 697 if (_connect(statp->_vcsock, nsap, nsaplen) < 0) { 698 *terrno = errno; 699 Aerror(statp, stderr, "connect/vc", errno, nsap, 700 nsaplen); 701 res_nclose(statp); 702 return (0); 703 } 704 statp->_flags |= RES_F_VC; 705 } 706 707 /* 708 * Send length & message 709 */ 710 ns_put16((u_short)buflen, (u_char*)&len); 711 iov[0] = evConsIovec(&len, INT16SZ); 712 DE_CONST(buf, tmp); 713 iov[1] = evConsIovec(tmp, buflen); 714 if (_writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) { 715 *terrno = errno; 716 Perror(statp, stderr, "write failed", errno); 717 res_nclose(statp); 718 return (0); 719 } 720 /* 721 * Receive length & response 722 */ 723 read_len: 724 cp = ans; 725 len = INT16SZ; 726 while ((n = _read(statp->_vcsock, (char *)cp, (int)len)) > 0) { 727 cp += n; 728 if ((len -= n) == 0) 729 break; 730 } 731 if (n <= 0) { 732 *terrno = errno; 733 Perror(statp, stderr, "read failed", errno); 734 res_nclose(statp); 735 /* 736 * A long running process might get its TCP 737 * connection reset if the remote server was 738 * restarted. Requery the server instead of 739 * trying a new one. When there is only one 740 * server, this means that a query might work 741 * instead of failing. We only allow one reset 742 * per query to prevent looping. 743 */ 744 if (*terrno == ECONNRESET && !connreset) { 745 connreset = 1; 746 res_nclose(statp); 747 goto same_ns; 748 } 749 res_nclose(statp); 750 return (0); 751 } 752 resplen = ns_get16(ans); 753 if (resplen > anssiz) { 754 Dprint(statp->options & RES_DEBUG, 755 (stdout, ";; response truncated\n") 756 ); 757 truncating = 1; 758 len = anssiz; 759 } else 760 len = resplen; 761 if (len < HFIXEDSZ) { 762 /* 763 * Undersized message. 764 */ 765 Dprint(statp->options & RES_DEBUG, 766 (stdout, ";; undersized: %d\n", len)); 767 *terrno = EMSGSIZE; 768 res_nclose(statp); 769 return (0); 770 } 771 cp = ans; 772 while (len != 0 && 773 (n = _read(statp->_vcsock, (char *)cp, (int)len)) > 0) { 774 cp += n; 775 len -= n; 776 } 777 if (n <= 0) { 778 *terrno = errno; 779 Perror(statp, stderr, "read(vc)", errno); 780 res_nclose(statp); 781 return (0); 782 } 783 if (truncating) { 784 /* 785 * Flush rest of answer so connection stays in synch. 786 */ 787 anhp->tc = 1; 788 len = resplen - anssiz; 789 while (len != 0) { 790 char junk[PACKETSZ]; 791 792 n = _read(statp->_vcsock, junk, 793 (len > sizeof junk) ? sizeof junk : len); 794 if (n > 0) 795 len -= n; 796 else 797 break; 798 } 799 } 800 /* 801 * If the calling applicating has bailed out of 802 * a previous call and failed to arrange to have 803 * the circuit closed or the server has got 804 * itself confused, then drop the packet and 805 * wait for the correct one. 806 */ 807 if (hp->id != anhp->id) { 808 DprintQ((statp->options & RES_DEBUG) || 809 (statp->pfcode & RES_PRF_REPLY), 810 (stdout, ";; old answer (unexpected):\n"), 811 ans, (resplen > anssiz) ? anssiz: resplen); 812 goto read_len; 813 } 814 815 /* 816 * All is well, or the error is fatal. Signal that the 817 * next nameserver ought not be tried. 818 */ 819 return (resplen); 820} 821 822static int 823send_dg(res_state statp, 824#ifdef USE_KQUEUE 825 int kq, 826#endif 827 const u_char *buf, int buflen, u_char *ans, 828 int anssiz, int *terrno, int ns, int tries, int *v_circuit, 829 int *gotsomewhere) 830{ 831 const HEADER *hp = (const HEADER *) buf; 832 HEADER *anhp = (HEADER *) ans; 833 const struct sockaddr *nsap; 834 int nsaplen; 835 struct timespec now, timeout, finish; 836 struct sockaddr_storage from; 837 ISC_SOCKLEN_T fromlen; 838 int resplen, seconds, n, s; 839#ifdef USE_KQUEUE 840 struct kevent kv; 841#else 842#ifdef USE_POLL 843 int polltimeout; 844 struct pollfd pollfd; 845#else 846 fd_set dsmask; 847#endif 848#endif 849 850 nsap = get_nsaddr(statp, ns); 851 nsaplen = get_salen(nsap); 852 if (EXT(statp).nssocks[ns] == -1) { 853 EXT(statp).nssocks[ns] = _socket(nsap->sa_family, 854 SOCK_DGRAM, 0); 855#if !defined(USE_POLL) && !defined(USE_KQUEUE) 856 if (EXT(statp).nssocks[ns] > highestFD) { 857 res_nclose(statp); 858 errno = ENOTSOCK; 859 } 860#endif 861 if (EXT(statp).nssocks[ns] < 0) { 862 switch (errno) { 863 case EPROTONOSUPPORT: 864#ifdef EPFNOSUPPORT 865 case EPFNOSUPPORT: 866#endif 867 case EAFNOSUPPORT: 868 Perror(statp, stderr, "socket(dg)", errno); 869 return (0); 870 default: 871 *terrno = errno; 872 Perror(statp, stderr, "socket(dg)", errno); 873 return (-1); 874 } 875 } 876#ifndef CANNOT_CONNECT_DGRAM 877 /* 878 * On a 4.3BSD+ machine (client and server, 879 * actually), sending to a nameserver datagram 880 * port with no nameserver will cause an 881 * ICMP port unreachable message to be returned. 882 * If our datagram socket is "connected" to the 883 * server, we get an ECONNREFUSED error on the next 884 * socket operation, and select returns if the 885 * error message is received. We can thus detect 886 * the absence of a nameserver without timing out. 887 * 888 * When the option "insecure1" is specified, we'd 889 * rather expect to see responses from an "unknown" 890 * address. In order to let the kernel accept such 891 * responses, do not connect the socket here. 892 * XXX: or do we need an explicit option to disable 893 * connecting? 894 */ 895 if (!(statp->options & RES_INSECURE1) && 896 _connect(EXT(statp).nssocks[ns], nsap, nsaplen) < 0) { 897 Aerror(statp, stderr, "connect(dg)", errno, nsap, 898 nsaplen); 899 res_nclose(statp); 900 return (0); 901 } 902#endif /* !CANNOT_CONNECT_DGRAM */ 903 Dprint(statp->options & RES_DEBUG, 904 (stdout, ";; new DG socket\n")) 905 } 906 s = EXT(statp).nssocks[ns]; 907#ifndef CANNOT_CONNECT_DGRAM 908 if (statp->options & RES_INSECURE1) { 909 if (_sendto(s, 910 (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) { 911 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); 912 res_nclose(statp); 913 return (0); 914 } 915 } else if (send(s, (const char*)buf, buflen, 0) != buflen) { 916 Perror(statp, stderr, "send", errno); 917 res_nclose(statp); 918 return (0); 919 } 920#else /* !CANNOT_CONNECT_DGRAM */ 921 if (_sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) 922 { 923 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); 924 res_nclose(statp); 925 return (0); 926 } 927#endif /* !CANNOT_CONNECT_DGRAM */ 928 929 /* 930 * Wait for reply. 931 */ 932 seconds = (statp->retrans << tries); 933 if (ns > 0) 934 seconds /= statp->nscount; 935 if (seconds <= 0) 936 seconds = 1; 937 now = evNowTime(); 938 timeout = evConsTime(seconds, 0); 939 finish = evAddTime(now, timeout); 940 goto nonow; 941 wait: 942 now = evNowTime(); 943 nonow: 944#ifndef USE_POLL 945 if (evCmpTime(finish, now) > 0) 946 timeout = evSubTime(finish, now); 947 else 948 timeout = evConsTime(0, 0); 949#ifdef USE_KQUEUE 950 EV_SET(&kv, s, EVFILT_READ, EV_ADD | EV_ONESHOT, 0, 0, 0); 951 n = _kevent(kq, &kv, 1, &kv, 1, &timeout); 952#else 953 FD_ZERO(&dsmask); 954 FD_SET(s, &dsmask); 955 n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL); 956#endif 957#else 958 timeout = evSubTime(finish, now); 959 if (timeout.tv_sec < 0) 960 timeout = evConsTime(0, 0); 961 polltimeout = 1000*timeout.tv_sec + 962 timeout.tv_nsec/1000000; 963 pollfd.fd = s; 964 pollfd.events = POLLRDNORM; 965 n = poll(&pollfd, 1, polltimeout); 966#endif /* USE_POLL */ 967 968 if (n == 0) { 969 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); 970 *gotsomewhere = 1; 971 return (0); 972 } 973 if (n < 0) { 974 if (errno == EINTR) 975 goto wait; 976#ifdef USE_KQUEUE 977 Perror(statp, stderr, "kevent", errno); 978#else 979#ifndef USE_POLL 980 Perror(statp, stderr, "select", errno); 981#else 982 Perror(statp, stderr, "poll", errno); 983#endif /* USE_POLL */ 984#endif 985 res_nclose(statp); 986 return (0); 987 } 988#ifdef USE_KQUEUE 989 if (kv.ident != s) 990 goto wait; 991#endif 992 errno = 0; 993 fromlen = sizeof(from); 994 resplen = _recvfrom(s, (char*)ans, anssiz,0, 995 (struct sockaddr *)&from, &fromlen); 996 if (resplen <= 0) { 997 Perror(statp, stderr, "recvfrom", errno); 998 res_nclose(statp); 999 return (0); 1000 } 1001 *gotsomewhere = 1; 1002 if (resplen < HFIXEDSZ) { 1003 /* 1004 * Undersized message. 1005 */ 1006 Dprint(statp->options & RES_DEBUG, 1007 (stdout, ";; undersized: %d\n", 1008 resplen)); 1009 *terrno = EMSGSIZE; 1010 res_nclose(statp); 1011 return (0); 1012 } 1013 if (hp->id != anhp->id) { 1014 /* 1015 * response from old query, ignore it. 1016 * XXX - potential security hazard could 1017 * be detected here. 1018 */ 1019 DprintQ((statp->options & RES_DEBUG) || 1020 (statp->pfcode & RES_PRF_REPLY), 1021 (stdout, ";; old answer:\n"), 1022 ans, (resplen > anssiz) ? anssiz : resplen); 1023 goto wait; 1024 } 1025 if (!(statp->options & RES_INSECURE1) && 1026 !res_ourserver_p(statp, (struct sockaddr *)&from)) { 1027 /* 1028 * response from wrong server? ignore it. 1029 * XXX - potential security hazard could 1030 * be detected here. 1031 */ 1032 DprintQ((statp->options & RES_DEBUG) || 1033 (statp->pfcode & RES_PRF_REPLY), 1034 (stdout, ";; not our server:\n"), 1035 ans, (resplen > anssiz) ? anssiz : resplen); 1036 goto wait; 1037 } 1038#ifdef RES_USE_EDNS0 1039 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) { 1040 /* 1041 * Do not retry if the server do not understand EDNS0. 1042 * The case has to be captured here, as FORMERR packet do not 1043 * carry query section, hence res_queriesmatch() returns 0. 1044 */ 1045 DprintQ(statp->options & RES_DEBUG, 1046 (stdout, "server rejected query with EDNS0:\n"), 1047 ans, (resplen > anssiz) ? anssiz : resplen); 1048 /* record the error */ 1049 statp->_flags |= RES_F_EDNS0ERR; 1050 res_nclose(statp); 1051 return (0); 1052 } 1053#endif 1054 if (!(statp->options & RES_INSECURE2) && 1055 !res_queriesmatch(buf, buf + buflen, 1056 ans, ans + anssiz)) { 1057 /* 1058 * response contains wrong query? ignore it. 1059 * XXX - potential security hazard could 1060 * be detected here. 1061 */ 1062 DprintQ((statp->options & RES_DEBUG) || 1063 (statp->pfcode & RES_PRF_REPLY), 1064 (stdout, ";; wrong query name:\n"), 1065 ans, (resplen > anssiz) ? anssiz : resplen); 1066 goto wait; 1067 } 1068 if (anhp->rcode == SERVFAIL || 1069 anhp->rcode == NOTIMP || 1070 anhp->rcode == REFUSED) { 1071 DprintQ(statp->options & RES_DEBUG, 1072 (stdout, "server rejected query:\n"), 1073 ans, (resplen > anssiz) ? anssiz : resplen); 1074 res_nclose(statp); 1075 /* don't retry if called from dig */ 1076 if (!statp->pfcode) 1077 return (0); 1078 } 1079 if (!(statp->options & RES_IGNTC) && anhp->tc) { 1080 /* 1081 * To get the rest of answer, 1082 * use TCP with same server. 1083 */ 1084 Dprint(statp->options & RES_DEBUG, 1085 (stdout, ";; truncated answer\n")); 1086 *v_circuit = 1; 1087 res_nclose(statp); 1088 return (1); 1089 } 1090 /* 1091 * All is well, or the error is fatal. Signal that the 1092 * next nameserver ought not be tried. 1093 */ 1094 return (resplen); 1095} 1096 1097static void 1098Aerror(const res_state statp, FILE *file, const char *string, int error, 1099 const struct sockaddr *address, int alen) 1100{ 1101 int save = errno; 1102 char hbuf[NI_MAXHOST]; 1103 char sbuf[NI_MAXSERV]; 1104 1105 if ((statp->options & RES_DEBUG) != 0U) { 1106 if (getnameinfo(address, alen, hbuf, sizeof(hbuf), 1107 sbuf, sizeof(sbuf), niflags)) { 1108 strncpy(hbuf, "?", sizeof(hbuf) - 1); 1109 hbuf[sizeof(hbuf) - 1] = '\0'; 1110 strncpy(sbuf, "?", sizeof(sbuf) - 1); 1111 sbuf[sizeof(sbuf) - 1] = '\0'; 1112 } 1113 fprintf(file, "res_send: %s ([%s].%s): %s\n", 1114 string, hbuf, sbuf, strerror(error)); 1115 } 1116 errno = save; 1117} 1118 1119static void 1120Perror(const res_state statp, FILE *file, const char *string, int error) { 1121 int save = errno; 1122 1123 if ((statp->options & RES_DEBUG) != 0U) 1124 fprintf(file, "res_send: %s: %s\n", 1125 string, strerror(error)); 1126 errno = save; 1127} 1128 1129static int 1130sock_eq(struct sockaddr *a, struct sockaddr *b) { 1131 struct sockaddr_in *a4, *b4; 1132 struct sockaddr_in6 *a6, *b6; 1133 1134 if (a->sa_family != b->sa_family) 1135 return 0; 1136 switch (a->sa_family) { 1137 case AF_INET: 1138 a4 = (struct sockaddr_in *)a; 1139 b4 = (struct sockaddr_in *)b; 1140 return a4->sin_port == b4->sin_port && 1141 a4->sin_addr.s_addr == b4->sin_addr.s_addr; 1142 case AF_INET6: 1143 a6 = (struct sockaddr_in6 *)a; 1144 b6 = (struct sockaddr_in6 *)b; 1145 return a6->sin6_port == b6->sin6_port && 1146#ifdef HAVE_SIN6_SCOPE_ID 1147 a6->sin6_scope_id == b6->sin6_scope_id && 1148#endif 1149 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr); 1150 default: 1151 return 0; 1152 } 1153} 1154 1155#if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE) 1156/* XXX needs to move to the porting library. */ 1157static int 1158pselect(int nfds, void *rfds, void *wfds, void *efds, 1159 struct timespec *tsp, const sigset_t *sigmask) 1160{ 1161 struct timeval tv, *tvp; 1162 sigset_t sigs; 1163 int n; 1164 1165 if (tsp) { 1166 tvp = &tv; 1167 tv = evTimeVal(*tsp); 1168 } else 1169 tvp = NULL; 1170 if (sigmask) 1171 sigprocmask(SIG_SETMASK, sigmask, &sigs); 1172 n = select(nfds, rfds, wfds, efds, tvp); 1173 if (sigmask) 1174 sigprocmask(SIG_SETMASK, &sigs, NULL); 1175 if (tsp) 1176 *tsp = evTimeSpec(tv); 1177 return (n); 1178} 1179#endif 1180