res_send.c revision 270838
1/* 2 * Portions Copyright (C) 2004-2009 Internet Systems Consortium, Inc. ("ISC") 3 * Portions Copyright (C) 1996-2003 Internet Software Consortium. 4 * 5 * Permission to use, copy, modify, and/or distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH 10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 15 * PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18/* 19 * Copyright (c) 1985, 1989, 1993 20 * The Regents of the University of California. All rights reserved. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the above copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 4. Neither the name of the University nor the names of its contributors 31 * may be used to endorse or promote products derived from this software 32 * without specific prior written permission. 33 * 34 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 35 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 37 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 38 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 39 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 40 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 41 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 42 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 43 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 44 * SUCH DAMAGE. 45 */ 46 47/* 48 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 49 * 50 * Permission to use, copy, modify, and distribute this software for any 51 * purpose with or without fee is hereby granted, provided that the above 52 * copyright notice and this permission notice appear in all copies, and that 53 * the name of Digital Equipment Corporation not be used in advertising or 54 * publicity pertaining to distribution of the document or software without 55 * specific, written prior permission. 56 * 57 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 58 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 59 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 60 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 61 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 62 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 63 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 64 * SOFTWARE. 65 */ 66 67#if defined(LIBC_SCCS) && !defined(lint) 68static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93"; 69static const char rcsid[] = "$Id: res_send.c,v 1.22 2009/01/22 23:49:23 tbox Exp $"; 70#endif /* LIBC_SCCS and not lint */ 71#include <sys/cdefs.h> 72__FBSDID("$FreeBSD: stable/10/lib/libc/resolv/res_send.c 270838 2014-08-30 10:16:25Z ume $"); 73 74/*! \file 75 * \brief 76 * Send query to name server and wait for reply. 77 */ 78 79#include "port_before.h" 80#ifndef USE_KQUEUE 81#include "fd_setsize.h" 82#endif 83 84#include "namespace.h" 85#include <sys/types.h> 86#include <sys/param.h> 87#include <sys/time.h> 88#include <sys/socket.h> 89#include <sys/uio.h> 90 91#include <netinet/in.h> 92#include <arpa/nameser.h> 93#include <arpa/inet.h> 94 95#include <errno.h> 96#include <netdb.h> 97#include <resolv.h> 98#include <signal.h> 99#include <stdio.h> 100#include <stdlib.h> 101#include <string.h> 102#include <unistd.h> 103 104#include <isc/eventlib.h> 105 106#include "port_after.h" 107 108#ifdef USE_KQUEUE 109#include <sys/event.h> 110#else 111#ifdef USE_POLL 112#ifdef HAVE_STROPTS_H 113#include <stropts.h> 114#endif 115#include <poll.h> 116#endif /* USE_POLL */ 117#endif 118 119#include "un-namespace.h" 120 121/* Options. Leave them on. */ 122#define DEBUG 123#include "res_debug.h" 124#include "res_private.h" 125 126#define EXT(res) ((res)->_u._ext) 127 128#if !defined(USE_POLL) && !defined(USE_KQUEUE) 129static const int highestFD = FD_SETSIZE - 1; 130#endif 131 132/* Forward. */ 133 134static int get_salen(const struct sockaddr *); 135static struct sockaddr * get_nsaddr(res_state, size_t); 136static int send_vc(res_state, const u_char *, int, 137 u_char *, int, int *, int); 138static int send_dg(res_state, 139#ifdef USE_KQUEUE 140 int kq, 141#endif 142 const u_char *, int, 143 u_char *, int, int *, int, int, 144 int *, int *); 145static void Aerror(const res_state, FILE *, const char *, int, 146 const struct sockaddr *, int); 147static void Perror(const res_state, FILE *, const char *, int); 148static int sock_eq(struct sockaddr *, struct sockaddr *); 149#if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE) 150static int pselect(int, void *, void *, void *, 151 struct timespec *, 152 const sigset_t *); 153#endif 154void res_pquery(const res_state, const u_char *, int, FILE *); 155 156static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV; 157 158/* Public. */ 159 160/*% 161 * looks up "ina" in _res.ns_addr_list[] 162 * 163 * returns: 164 *\li 0 : not found 165 *\li >0 : found 166 * 167 * author: 168 *\li paul vixie, 29may94 169 */ 170int 171res_ourserver_p(const res_state statp, const struct sockaddr *sa) { 172 const struct sockaddr_in *inp, *srv; 173 const struct sockaddr_in6 *in6p, *srv6; 174 int ns; 175 176 switch (sa->sa_family) { 177 case AF_INET: 178 inp = (const struct sockaddr_in *)sa; 179 for (ns = 0; ns < statp->nscount; ns++) { 180 srv = (struct sockaddr_in *)get_nsaddr(statp, ns); 181 if (srv->sin_family == inp->sin_family && 182 srv->sin_port == inp->sin_port && 183 (srv->sin_addr.s_addr == INADDR_ANY || 184 srv->sin_addr.s_addr == inp->sin_addr.s_addr)) 185 return (1); 186 } 187 break; 188 case AF_INET6: 189 if (EXT(statp).ext == NULL) 190 break; 191 in6p = (const struct sockaddr_in6 *)sa; 192 for (ns = 0; ns < statp->nscount; ns++) { 193 srv6 = (struct sockaddr_in6 *)get_nsaddr(statp, ns); 194 if (srv6->sin6_family == in6p->sin6_family && 195 srv6->sin6_port == in6p->sin6_port && 196#ifdef HAVE_SIN6_SCOPE_ID 197 (srv6->sin6_scope_id == 0 || 198 srv6->sin6_scope_id == in6p->sin6_scope_id) && 199#endif 200 (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) || 201 IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr))) 202 return (1); 203 } 204 break; 205 default: 206 break; 207 } 208 return (0); 209} 210 211/*% 212 * look for (name,type,class) in the query section of packet (buf,eom) 213 * 214 * requires: 215 *\li buf + HFIXEDSZ <= eom 216 * 217 * returns: 218 *\li -1 : format error 219 *\li 0 : not found 220 *\li >0 : found 221 * 222 * author: 223 *\li paul vixie, 29may94 224 */ 225int 226res_nameinquery(const char *name, int type, int class, 227 const u_char *buf, const u_char *eom) 228{ 229 const u_char *cp = buf + HFIXEDSZ; 230 int qdcount = ntohs(((const HEADER*)buf)->qdcount); 231 232 while (qdcount-- > 0) { 233 char tname[MAXDNAME+1]; 234 int n, ttype, tclass; 235 236 n = dn_expand(buf, eom, cp, tname, sizeof tname); 237 if (n < 0) 238 return (-1); 239 cp += n; 240 if (cp + 2 * INT16SZ > eom) 241 return (-1); 242 ttype = ns_get16(cp); cp += INT16SZ; 243 tclass = ns_get16(cp); cp += INT16SZ; 244 if (ttype == type && tclass == class && 245 ns_samename(tname, name) == 1) 246 return (1); 247 } 248 return (0); 249} 250 251/*% 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 (_getpeername(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 | 664 SOCK_CLOEXEC, 0); 665#if !defined(USE_POLL) && !defined(USE_KQUEUE) 666 if (statp->_vcsock > highestFD) { 667 res_nclose(statp); 668 errno = ENOTSOCK; 669 } 670#endif 671 if (statp->_vcsock < 0) { 672 switch (errno) { 673 case EPROTONOSUPPORT: 674#ifdef EPFNOSUPPORT 675 case EPFNOSUPPORT: 676#endif 677 case EAFNOSUPPORT: 678 Perror(statp, stderr, "socket(vc)", errno); 679 return (0); 680 default: 681 *terrno = errno; 682 Perror(statp, stderr, "socket(vc)", errno); 683 return (-1); 684 } 685 } 686#ifdef SO_NOSIGPIPE 687 /* 688 * Disable generation of SIGPIPE when writing to a closed 689 * socket. Write should return -1 and set errno to EPIPE 690 * instead. 691 * 692 * Push on even if setsockopt(SO_NOSIGPIPE) fails. 693 */ 694 (void)_setsockopt(statp->_vcsock, SOL_SOCKET, SO_NOSIGPIPE, &on, 695 sizeof(on)); 696#endif 697 errno = 0; 698 if (_connect(statp->_vcsock, nsap, nsaplen) < 0) { 699 *terrno = errno; 700 Aerror(statp, stderr, "connect/vc", errno, nsap, 701 nsaplen); 702 res_nclose(statp); 703 return (0); 704 } 705 statp->_flags |= RES_F_VC; 706 } 707 708 /* 709 * Send length & message 710 */ 711 ns_put16((u_short)buflen, (u_char*)&len); 712 iov[0] = evConsIovec(&len, INT16SZ); 713 DE_CONST(buf, tmp); 714 iov[1] = evConsIovec(tmp, buflen); 715 if (_writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) { 716 *terrno = errno; 717 Perror(statp, stderr, "write failed", errno); 718 res_nclose(statp); 719 return (0); 720 } 721 /* 722 * Receive length & response 723 */ 724 read_len: 725 cp = ans; 726 len = INT16SZ; 727 while ((n = _read(statp->_vcsock, (char *)cp, (int)len)) > 0) { 728 cp += n; 729 if ((len -= n) == 0) 730 break; 731 } 732 if (n <= 0) { 733 *terrno = errno; 734 Perror(statp, stderr, "read failed", errno); 735 res_nclose(statp); 736 /* 737 * A long running process might get its TCP 738 * connection reset if the remote server was 739 * restarted. Requery the server instead of 740 * trying a new one. When there is only one 741 * server, this means that a query might work 742 * instead of failing. We only allow one reset 743 * per query to prevent looping. 744 */ 745 if (*terrno == ECONNRESET && !connreset) { 746 connreset = 1; 747 res_nclose(statp); 748 goto same_ns; 749 } 750 res_nclose(statp); 751 return (0); 752 } 753 resplen = ns_get16(ans); 754 if (resplen > anssiz) { 755 Dprint(statp->options & RES_DEBUG, 756 (stdout, ";; response truncated\n") 757 ); 758 truncating = 1; 759 len = anssiz; 760 } else 761 len = resplen; 762 if (len < HFIXEDSZ) { 763 /* 764 * Undersized message. 765 */ 766 Dprint(statp->options & RES_DEBUG, 767 (stdout, ";; undersized: %d\n", len)); 768 *terrno = EMSGSIZE; 769 res_nclose(statp); 770 return (0); 771 } 772 cp = ans; 773 while (len != 0 && 774 (n = _read(statp->_vcsock, (char *)cp, (int)len)) > 0) { 775 cp += n; 776 len -= n; 777 } 778 if (n <= 0) { 779 *terrno = errno; 780 Perror(statp, stderr, "read(vc)", errno); 781 res_nclose(statp); 782 return (0); 783 } 784 if (truncating) { 785 /* 786 * Flush rest of answer so connection stays in synch. 787 */ 788 anhp->tc = 1; 789 len = resplen - anssiz; 790 while (len != 0) { 791 char junk[PACKETSZ]; 792 793 n = _read(statp->_vcsock, junk, 794 (len > sizeof junk) ? sizeof junk : len); 795 if (n > 0) 796 len -= n; 797 else 798 break; 799 } 800 } 801 /* 802 * If the calling applicating has bailed out of 803 * a previous call and failed to arrange to have 804 * the circuit closed or the server has got 805 * itself confused, then drop the packet and 806 * wait for the correct one. 807 */ 808 if (hp->id != anhp->id) { 809 DprintQ((statp->options & RES_DEBUG) || 810 (statp->pfcode & RES_PRF_REPLY), 811 (stdout, ";; old answer (unexpected):\n"), 812 ans, (resplen > anssiz) ? anssiz: resplen); 813 goto read_len; 814 } 815 816 /* 817 * All is well, or the error is fatal. Signal that the 818 * next nameserver ought not be tried. 819 */ 820 return (resplen); 821} 822 823static int 824send_dg(res_state statp, 825#ifdef USE_KQUEUE 826 int kq, 827#endif 828 const u_char *buf, int buflen, u_char *ans, 829 int anssiz, int *terrno, int ns, int tries, int *v_circuit, 830 int *gotsomewhere) 831{ 832 const HEADER *hp = (const HEADER *) buf; 833 HEADER *anhp = (HEADER *) ans; 834 const struct sockaddr *nsap; 835 int nsaplen; 836 struct timespec now, timeout, finish; 837 struct sockaddr_storage from; 838 ISC_SOCKLEN_T fromlen; 839 int resplen, seconds, n, s; 840#ifdef USE_KQUEUE 841 struct kevent kv; 842#else 843#ifdef USE_POLL 844 int polltimeout; 845 struct pollfd pollfd; 846#else 847 fd_set dsmask; 848#endif 849#endif 850 851 nsap = get_nsaddr(statp, ns); 852 nsaplen = get_salen(nsap); 853 if (EXT(statp).nssocks[ns] == -1) { 854 EXT(statp).nssocks[ns] = _socket(nsap->sa_family, 855 SOCK_DGRAM | SOCK_CLOEXEC, 0); 856#if !defined(USE_POLL) && !defined(USE_KQUEUE) 857 if (EXT(statp).nssocks[ns] > highestFD) { 858 res_nclose(statp); 859 errno = ENOTSOCK; 860 } 861#endif 862 if (EXT(statp).nssocks[ns] < 0) { 863 switch (errno) { 864 case EPROTONOSUPPORT: 865#ifdef EPFNOSUPPORT 866 case EPFNOSUPPORT: 867#endif 868 case EAFNOSUPPORT: 869 Perror(statp, stderr, "socket(dg)", errno); 870 return (0); 871 default: 872 *terrno = errno; 873 Perror(statp, stderr, "socket(dg)", errno); 874 return (-1); 875 } 876 } 877#ifndef CANNOT_CONNECT_DGRAM 878 /* 879 * On a 4.3BSD+ machine (client and server, 880 * actually), sending to a nameserver datagram 881 * port with no nameserver will cause an 882 * ICMP port unreachable message to be returned. 883 * If our datagram socket is "connected" to the 884 * server, we get an ECONNREFUSED error on the next 885 * socket operation, and select returns if the 886 * error message is received. We can thus detect 887 * the absence of a nameserver without timing out. 888 * 889 * When the option "insecure1" is specified, we'd 890 * rather expect to see responses from an "unknown" 891 * address. In order to let the kernel accept such 892 * responses, do not connect the socket here. 893 * XXX: or do we need an explicit option to disable 894 * connecting? 895 */ 896 if (!(statp->options & RES_INSECURE1) && 897 _connect(EXT(statp).nssocks[ns], nsap, nsaplen) < 0) { 898 Aerror(statp, stderr, "connect(dg)", errno, nsap, 899 nsaplen); 900 res_nclose(statp); 901 return (0); 902 } 903#endif /* !CANNOT_CONNECT_DGRAM */ 904 Dprint(statp->options & RES_DEBUG, 905 (stdout, ";; new DG socket\n")) 906 } 907 s = EXT(statp).nssocks[ns]; 908#ifndef CANNOT_CONNECT_DGRAM 909 if (statp->options & RES_INSECURE1) { 910 if (_sendto(s, 911 (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) { 912 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); 913 res_nclose(statp); 914 return (0); 915 } 916 } else if (send(s, (const char*)buf, buflen, 0) != buflen) { 917 Perror(statp, stderr, "send", errno); 918 res_nclose(statp); 919 return (0); 920 } 921#else /* !CANNOT_CONNECT_DGRAM */ 922 if (_sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) 923 { 924 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); 925 res_nclose(statp); 926 return (0); 927 } 928#endif /* !CANNOT_CONNECT_DGRAM */ 929 930 /* 931 * Wait for reply. 932 */ 933 seconds = (statp->retrans << tries); 934 if (ns > 0) 935 seconds /= statp->nscount; 936 if (seconds <= 0) 937 seconds = 1; 938 now = evNowTime(); 939 timeout = evConsTime(seconds, 0); 940 finish = evAddTime(now, timeout); 941 goto nonow; 942 wait: 943 now = evNowTime(); 944 nonow: 945#ifndef USE_POLL 946 if (evCmpTime(finish, now) > 0) 947 timeout = evSubTime(finish, now); 948 else 949 timeout = evConsTime(0, 0); 950#ifdef USE_KQUEUE 951 EV_SET(&kv, s, EVFILT_READ, EV_ADD | EV_ONESHOT, 0, 0, 0); 952 n = _kevent(kq, &kv, 1, &kv, 1, &timeout); 953#else 954 FD_ZERO(&dsmask); 955 FD_SET(s, &dsmask); 956 n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL); 957#endif 958#else 959 timeout = evSubTime(finish, now); 960 if (timeout.tv_sec < 0) 961 timeout = evConsTime(0, 0); 962 polltimeout = 1000*timeout.tv_sec + 963 timeout.tv_nsec/1000000; 964 pollfd.fd = s; 965 pollfd.events = POLLRDNORM; 966 n = poll(&pollfd, 1, polltimeout); 967#endif /* USE_POLL */ 968 969 if (n == 0) { 970 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); 971 *gotsomewhere = 1; 972 return (0); 973 } 974 if (n < 0) { 975 if (errno == EINTR) 976 goto wait; 977#ifdef USE_KQUEUE 978 Perror(statp, stderr, "kevent", errno); 979#else 980#ifndef USE_POLL 981 Perror(statp, stderr, "select", errno); 982#else 983 Perror(statp, stderr, "poll", errno); 984#endif /* USE_POLL */ 985#endif 986 res_nclose(statp); 987 return (0); 988 } 989#ifdef USE_KQUEUE 990 if (kv.ident != s) 991 goto wait; 992#endif 993 errno = 0; 994 fromlen = sizeof(from); 995 resplen = _recvfrom(s, (char*)ans, anssiz,0, 996 (struct sockaddr *)&from, &fromlen); 997 if (resplen <= 0) { 998 Perror(statp, stderr, "recvfrom", errno); 999 res_nclose(statp); 1000 return (0); 1001 } 1002 *gotsomewhere = 1; 1003 if (resplen < HFIXEDSZ) { 1004 /* 1005 * Undersized message. 1006 */ 1007 Dprint(statp->options & RES_DEBUG, 1008 (stdout, ";; undersized: %d\n", 1009 resplen)); 1010 *terrno = EMSGSIZE; 1011 res_nclose(statp); 1012 return (0); 1013 } 1014 if (hp->id != anhp->id) { 1015 /* 1016 * response from old query, ignore it. 1017 * XXX - potential security hazard could 1018 * be detected here. 1019 */ 1020 DprintQ((statp->options & RES_DEBUG) || 1021 (statp->pfcode & RES_PRF_REPLY), 1022 (stdout, ";; old answer:\n"), 1023 ans, (resplen > anssiz) ? anssiz : resplen); 1024 goto wait; 1025 } 1026 if (!(statp->options & RES_INSECURE1) && 1027 !res_ourserver_p(statp, (struct sockaddr *)&from)) { 1028 /* 1029 * response from wrong server? ignore it. 1030 * XXX - potential security hazard could 1031 * be detected here. 1032 */ 1033 DprintQ((statp->options & RES_DEBUG) || 1034 (statp->pfcode & RES_PRF_REPLY), 1035 (stdout, ";; not our server:\n"), 1036 ans, (resplen > anssiz) ? anssiz : resplen); 1037 goto wait; 1038 } 1039#ifdef RES_USE_EDNS0 1040 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) { 1041 /* 1042 * Do not retry if the server do not understand EDNS0. 1043 * The case has to be captured here, as FORMERR packet do not 1044 * carry query section, hence res_queriesmatch() returns 0. 1045 */ 1046 DprintQ(statp->options & RES_DEBUG, 1047 (stdout, "server rejected query with EDNS0:\n"), 1048 ans, (resplen > anssiz) ? anssiz : resplen); 1049 /* record the error */ 1050 statp->_flags |= RES_F_EDNS0ERR; 1051 res_nclose(statp); 1052 return (0); 1053 } 1054#endif 1055 if (!(statp->options & RES_INSECURE2) && 1056 !res_queriesmatch(buf, buf + buflen, 1057 ans, ans + anssiz)) { 1058 /* 1059 * response contains wrong query? ignore it. 1060 * XXX - potential security hazard could 1061 * be detected here. 1062 */ 1063 DprintQ((statp->options & RES_DEBUG) || 1064 (statp->pfcode & RES_PRF_REPLY), 1065 (stdout, ";; wrong query name:\n"), 1066 ans, (resplen > anssiz) ? anssiz : resplen); 1067 goto wait; 1068 } 1069 if (anhp->rcode == SERVFAIL || 1070 anhp->rcode == NOTIMP || 1071 anhp->rcode == REFUSED) { 1072 DprintQ(statp->options & RES_DEBUG, 1073 (stdout, "server rejected query:\n"), 1074 ans, (resplen > anssiz) ? anssiz : resplen); 1075 res_nclose(statp); 1076 /* don't retry if called from dig */ 1077 if (!statp->pfcode) 1078 return (0); 1079 } 1080 if (!(statp->options & RES_IGNTC) && anhp->tc) { 1081 /* 1082 * To get the rest of answer, 1083 * use TCP with same server. 1084 */ 1085 Dprint(statp->options & RES_DEBUG, 1086 (stdout, ";; truncated answer\n")); 1087 *v_circuit = 1; 1088 res_nclose(statp); 1089 return (1); 1090 } 1091 /* 1092 * All is well, or the error is fatal. Signal that the 1093 * next nameserver ought not be tried. 1094 */ 1095 return (resplen); 1096} 1097 1098static void 1099Aerror(const res_state statp, FILE *file, const char *string, int error, 1100 const struct sockaddr *address, int alen) 1101{ 1102 int save = errno; 1103 char hbuf[NI_MAXHOST]; 1104 char sbuf[NI_MAXSERV]; 1105 1106 if ((statp->options & RES_DEBUG) != 0U) { 1107 if (getnameinfo(address, alen, hbuf, sizeof(hbuf), 1108 sbuf, sizeof(sbuf), niflags)) { 1109 strncpy(hbuf, "?", sizeof(hbuf) - 1); 1110 hbuf[sizeof(hbuf) - 1] = '\0'; 1111 strncpy(sbuf, "?", sizeof(sbuf) - 1); 1112 sbuf[sizeof(sbuf) - 1] = '\0'; 1113 } 1114 fprintf(file, "res_send: %s ([%s].%s): %s\n", 1115 string, hbuf, sbuf, strerror(error)); 1116 } 1117 errno = save; 1118} 1119 1120static void 1121Perror(const res_state statp, FILE *file, const char *string, int error) { 1122 int save = errno; 1123 1124 if ((statp->options & RES_DEBUG) != 0U) 1125 fprintf(file, "res_send: %s: %s\n", 1126 string, strerror(error)); 1127 errno = save; 1128} 1129 1130static int 1131sock_eq(struct sockaddr *a, struct sockaddr *b) { 1132 struct sockaddr_in *a4, *b4; 1133 struct sockaddr_in6 *a6, *b6; 1134 1135 if (a->sa_family != b->sa_family) 1136 return 0; 1137 switch (a->sa_family) { 1138 case AF_INET: 1139 a4 = (struct sockaddr_in *)a; 1140 b4 = (struct sockaddr_in *)b; 1141 return a4->sin_port == b4->sin_port && 1142 a4->sin_addr.s_addr == b4->sin_addr.s_addr; 1143 case AF_INET6: 1144 a6 = (struct sockaddr_in6 *)a; 1145 b6 = (struct sockaddr_in6 *)b; 1146 return a6->sin6_port == b6->sin6_port && 1147#ifdef HAVE_SIN6_SCOPE_ID 1148 a6->sin6_scope_id == b6->sin6_scope_id && 1149#endif 1150 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr); 1151 default: 1152 return 0; 1153 } 1154} 1155 1156#if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE) 1157/* XXX needs to move to the porting library. */ 1158static int 1159pselect(int nfds, void *rfds, void *wfds, void *efds, 1160 struct timespec *tsp, const sigset_t *sigmask) 1161{ 1162 struct timeval tv, *tvp; 1163 sigset_t sigs; 1164 int n; 1165 1166 if (tsp) { 1167 tvp = &tv; 1168 tv = evTimeVal(*tsp); 1169 } else 1170 tvp = NULL; 1171 if (sigmask) 1172 sigprocmask(SIG_SETMASK, sigmask, &sigs); 1173 n = select(nfds, rfds, wfds, efds, tvp); 1174 if (sigmask) 1175 sigprocmask(SIG_SETMASK, &sigs, NULL); 1176 if (tsp) 1177 *tsp = evTimeSpec(tv); 1178 return (n); 1179} 1180#endif 1181