1 /* $NetBSD: res_send.c,v 1.15 2008/06/21 23:37:53 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1985, 1989, 1993 5 * The Regents of the University of California. 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 /* 37 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 38 * 39 * Permission to use, copy, modify, and distribute this software for any 40 * purpose with or without fee is hereby granted, provided that the above 41 * copyright notice and this permission notice appear in all copies, and that 42 * the name of Digital Equipment Corporation not be used in advertising or 43 * publicity pertaining to distribution of the document or software without 44 * specific, written prior permission. 45 * 46 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 47 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 48 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 49 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 50 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 51 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 52 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 53 * SOFTWARE. 54 */ 55 56 /* 57 * Copyright (c) 2005 by Internet Systems Consortium, Inc. ("ISC") 58 * Portions Copyright (c) 1996-1999 by Internet Software Consortium. 59 * 60 * Permission to use, copy, modify, and distribute this software for any 61 * purpose with or without fee is hereby granted, provided that the above 62 * copyright notice and this permission notice appear in all copies. 63 * 64 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 65 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 66 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 67 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 68 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 69 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 70 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 71 */ 72 73 #include <sys/cdefs.h> 74 #if defined(LIBC_SCCS) && !defined(lint) 75 #ifdef notdef 76 static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93"; 77 static const char rcsid[] = "Id: res_send.c,v 1.18.10.1 2008/01/27 02:06:46 marka Exp"; 78 #else 79 __RCSID("$NetBSD: res_send.c,v 1.15 2008/06/21 23:37:53 christos Exp $"); 80 #endif 81 #endif /* LIBC_SCCS and not lint */ 82 83 /*! \file 84 * \brief 85 * Send query to name server and wait for reply. 86 */ 87 88 #include "namespace.h" 89 #include "port_before.h" 90 #include "fd_setsize.h" 91 92 #include <sys/types.h> 93 #include <sys/param.h> 94 #include <sys/time.h> 95 #include <sys/socket.h> 96 #include <sys/uio.h> 97 98 #include <netinet/in.h> 99 #include <arpa/nameser.h> 100 #include <arpa/inet.h> 101 102 #include <errno.h> 103 #include <netdb.h> 104 #include <resolv.h> 105 #include <signal.h> 106 #include <stdio.h> 107 #include <stdlib.h> 108 #include <string.h> 109 #include <unistd.h> 110 111 #include <isc/eventlib.h> 112 113 #include "port_after.h" 114 115 #if 0 116 #ifdef __weak_alias 117 __weak_alias(res_ourserver_p,__res_ourserver_p) 118 __weak_alias(res_nameinquery,__res_nameinquery) 119 __weak_alias(res_queriesmatch,__res_queriesmatch) 120 __weak_alias(res_nsend,__res_nsend) 121 #endif 122 #endif 123 124 125 #ifdef USE_POLL 126 #ifdef HAVE_STROPTS_H 127 #include <stropts.h> 128 #endif 129 #include <poll.h> 130 #endif /* USE_POLL */ 131 132 /* Options. Leave them on. */ 133 #ifndef DEBUG 134 #define DEBUG 135 #endif 136 #include "res_debug.h" 137 #include "res_private.h" 138 139 #define EXT(res) ((res)->_u._ext) 140 141 #ifndef USE_POLL 142 static const int highestFD = FD_SETSIZE - 1; 143 #else 144 static int highestFD = 0; 145 #endif 146 147 /* Forward. */ 148 149 static int get_salen __P((const struct sockaddr *)); 150 static struct sockaddr * get_nsaddr __P((res_state, size_t)); 151 static int send_vc(res_state, const u_char *, int, 152 u_char *, int, int *, int); 153 static int send_dg(res_state, const u_char *, int, 154 u_char *, int, int *, int, int, 155 int *, int *); 156 static void Aerror(const res_state, FILE *, const char *, int, 157 const struct sockaddr *, int); 158 static void Perror(const res_state, FILE *, const char *, int); 159 static int sock_eq(struct sockaddr *, struct sockaddr *); 160 #if defined(NEED_PSELECT) && !defined(USE_POLL) 161 static int pselect(int, void *, void *, void *, 162 struct timespec *, 163 const sigset_t *); 164 #endif 165 void res_pquery(const res_state, const u_char *, int, FILE *); 166 167 static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV; 168 169 /* Public. */ 170 171 /*% 172 * looks up "ina" in _res.ns_addr_list[] 173 * 174 * returns: 175 *\li 0 : not found 176 *\li >0 : found 177 * 178 * author: 179 *\li paul vixie, 29may94 180 */ 181 int 182 res_ourserver_p(const res_state statp, const struct sockaddr *sa) { 183 const struct sockaddr_in *inp, *srv; 184 const struct sockaddr_in6 *in6p, *srv6; 185 int ns; 186 187 switch (sa->sa_family) { 188 case AF_INET: 189 inp = (const struct sockaddr_in *)(const void *)sa; 190 for (ns = 0; ns < statp->nscount; ns++) { 191 srv = (struct sockaddr_in *)(void *)get_nsaddr(statp, (size_t)ns); 192 if (srv->sin_family == inp->sin_family && 193 srv->sin_port == inp->sin_port && 194 (srv->sin_addr.s_addr == INADDR_ANY || 195 srv->sin_addr.s_addr == inp->sin_addr.s_addr)) 196 return (1); 197 } 198 break; 199 case AF_INET6: 200 if (EXT(statp).ext == NULL) 201 break; 202 in6p = (const struct sockaddr_in6 *)(const void *)sa; 203 for (ns = 0; ns < statp->nscount; ns++) { 204 srv6 = (struct sockaddr_in6 *)(void *)get_nsaddr(statp, (size_t)ns); 205 if (srv6->sin6_family == in6p->sin6_family && 206 srv6->sin6_port == in6p->sin6_port && 207 #ifdef HAVE_SIN6_SCOPE_ID 208 (srv6->sin6_scope_id == 0 || 209 srv6->sin6_scope_id == in6p->sin6_scope_id) && 210 #endif 211 (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) || 212 IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr))) 213 return (1); 214 } 215 break; 216 default: 217 break; 218 } 219 return (0); 220 } 221 222 /*% 223 * look for (name,type,class) in the query section of packet (buf,eom) 224 * 225 * requires: 226 *\li buf + HFIXEDSZ <= eom 227 * 228 * returns: 229 *\li -1 : format error 230 *\li 0 : not found 231 *\li >0 : found 232 * 233 * author: 234 *\li paul vixie, 29may94 235 */ 236 int 237 res_nameinquery(const char *name, int type, int class, 238 const u_char *buf, const u_char *eom) 239 { 240 const u_char *cp = buf + HFIXEDSZ; 241 int qdcount = ntohs(((const HEADER*)(const void *)buf)->qdcount); 242 243 while (qdcount-- > 0) { 244 char tname[MAXDNAME+1]; 245 int n, ttype, tclass; 246 247 n = dn_expand(buf, eom, cp, tname, sizeof tname); 248 if (n < 0) 249 return (-1); 250 cp += n; 251 if (cp + 2 * INT16SZ > eom) 252 return (-1); 253 ttype = ns_get16(cp); cp += INT16SZ; 254 tclass = ns_get16(cp); cp += INT16SZ; 255 if (ttype == type && tclass == class && 256 ns_samename(tname, name) == 1) 257 return (1); 258 } 259 return (0); 260 } 261 262 /*% 263 * is there a 1:1 mapping of (name,type,class) 264 * in (buf1,eom1) and (buf2,eom2)? 265 * 266 * returns: 267 *\li -1 : format error 268 *\li 0 : not a 1:1 mapping 269 *\li >0 : is a 1:1 mapping 270 * 271 * author: 272 *\li paul vixie, 29may94 273 */ 274 int 275 res_queriesmatch(const u_char *buf1, const u_char *eom1, 276 const u_char *buf2, const u_char *eom2) 277 { 278 const u_char *cp = buf1 + HFIXEDSZ; 279 int qdcount = ntohs(((const HEADER*)(const void *)buf1)->qdcount); 280 281 if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2) 282 return (-1); 283 284 /* 285 * Only header section present in replies to 286 * dynamic update packets. 287 */ 288 if ((((const HEADER *)(const void *)buf1)->opcode == ns_o_update) && 289 (((const HEADER *)(const void *)buf2)->opcode == ns_o_update)) 290 return (1); 291 292 if (qdcount != ntohs(((const HEADER*)(const void *)buf2)->qdcount)) 293 return (0); 294 while (qdcount-- > 0) { 295 char tname[MAXDNAME+1]; 296 int n, ttype, tclass; 297 298 n = dn_expand(buf1, eom1, cp, tname, sizeof tname); 299 if (n < 0) 300 return (-1); 301 cp += n; 302 if (cp + 2 * INT16SZ > eom1) 303 return (-1); 304 ttype = ns_get16(cp); cp += INT16SZ; 305 tclass = ns_get16(cp); cp += INT16SZ; 306 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) 307 return (0); 308 } 309 return (1); 310 } 311 312 int 313 res_nsend(res_state statp, 314 const u_char *buf, int buflen, u_char *ans, int anssiz) 315 { 316 int gotsomewhere, terrno, tries, v_circuit, resplen, ns, n; 317 char abuf[NI_MAXHOST]; 318 319 #ifdef USE_POLL 320 highestFD = sysconf(_SC_OPEN_MAX) - 1; 321 #endif 322 323 /* No name servers or res_init() failure */ 324 if (statp->nscount == 0 || EXT(statp).ext == NULL) { 325 errno = ESRCH; 326 return (-1); 327 } 328 if (anssiz < HFIXEDSZ) { 329 errno = EINVAL; 330 return (-1); 331 } 332 DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY), 333 (stdout, ";; res_send()\n"), buf, buflen); 334 v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ; 335 gotsomewhere = 0; 336 terrno = ETIMEDOUT; 337 338 /* 339 * If the ns_addr_list in the resolver context has changed, then 340 * invalidate our cached copy and the associated timing data. 341 */ 342 if (EXT(statp).nscount != 0) { 343 int needclose = 0; 344 struct sockaddr_storage peer; 345 ISC_SOCKLEN_T peerlen; 346 347 if (EXT(statp).nscount != statp->nscount) 348 needclose++; 349 else 350 for (ns = 0; ns < statp->nscount; ns++) { 351 if (statp->nsaddr_list[ns].sin_family && 352 !sock_eq((struct sockaddr *)(void *)&statp->nsaddr_list[ns], 353 (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[ns])) { 354 needclose++; 355 break; 356 } 357 358 if (EXT(statp).nssocks[ns] == -1) 359 continue; 360 peerlen = sizeof(peer); 361 if (getsockname(EXT(statp).nssocks[ns], 362 (struct sockaddr *)(void *)&peer, &peerlen) < 0) { 363 needclose++; 364 break; 365 } 366 if (!sock_eq((struct sockaddr *)(void *)&peer, 367 get_nsaddr(statp, (size_t)ns))) { 368 needclose++; 369 break; 370 } 371 } 372 if (needclose) { 373 res_nclose(statp); 374 EXT(statp).nscount = 0; 375 } 376 } 377 378 /* 379 * Maybe initialize our private copy of the ns_addr_list. 380 */ 381 if (EXT(statp).nscount == 0) { 382 for (ns = 0; ns < statp->nscount; ns++) { 383 EXT(statp).nstimes[ns] = RES_MAXTIME; 384 EXT(statp).nssocks[ns] = -1; 385 if (!statp->nsaddr_list[ns].sin_family) 386 continue; 387 EXT(statp).ext->nsaddrs[ns].sin = 388 statp->nsaddr_list[ns]; 389 } 390 EXT(statp).nscount = statp->nscount; 391 } 392 393 /* 394 * Some resolvers want to even out the load on their nameservers. 395 * Note that RES_BLAST overrides RES_ROTATE. 396 */ 397 if ((statp->options & RES_ROTATE) != 0U && 398 (statp->options & RES_BLAST) == 0U) { 399 union res_sockaddr_union inu; 400 struct sockaddr_in ina; 401 int lastns = statp->nscount - 1; 402 int fd; 403 u_int16_t nstime; 404 405 if (EXT(statp).ext != NULL) 406 inu = EXT(statp).ext->nsaddrs[0]; 407 ina = statp->nsaddr_list[0]; 408 fd = EXT(statp).nssocks[0]; 409 nstime = EXT(statp).nstimes[0]; 410 for (ns = 0; ns < lastns; ns++) { 411 if (EXT(statp).ext != NULL) 412 EXT(statp).ext->nsaddrs[ns] = 413 EXT(statp).ext->nsaddrs[ns + 1]; 414 statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1]; 415 EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1]; 416 EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1]; 417 } 418 if (EXT(statp).ext != NULL) 419 EXT(statp).ext->nsaddrs[lastns] = inu; 420 statp->nsaddr_list[lastns] = ina; 421 EXT(statp).nssocks[lastns] = fd; 422 EXT(statp).nstimes[lastns] = nstime; 423 } 424 425 /* 426 * Send request, RETRY times, or until successful. 427 */ 428 for (tries = 0; tries < statp->retry; tries++) { 429 for (ns = 0; ns < statp->nscount; ns++) { 430 struct sockaddr *nsap; 431 int nsaplen; 432 nsap = get_nsaddr(statp, (size_t)ns); 433 nsaplen = get_salen(nsap); 434 statp->_flags &= ~RES_F_LASTMASK; 435 statp->_flags |= (ns << RES_F_LASTSHIFT); 436 same_ns: 437 if (statp->qhook) { 438 int done = 0, loops = 0; 439 440 do { 441 res_sendhookact act; 442 443 act = (*statp->qhook)(&nsap, &buf, &buflen, 444 ans, anssiz, &resplen); 445 switch (act) { 446 case res_goahead: 447 done = 1; 448 break; 449 case res_nextns: 450 res_nclose(statp); 451 goto next_ns; 452 case res_done: 453 return (resplen); 454 case res_modified: 455 /* give the hook another try */ 456 if (++loops < 42) /*doug adams*/ 457 break; 458 /*FALLTHROUGH*/ 459 case res_error: 460 /*FALLTHROUGH*/ 461 default: 462 goto fail; 463 } 464 } while (!done); 465 } 466 467 Dprint(((statp->options & RES_DEBUG) && 468 getnameinfo(nsap, (socklen_t)nsaplen, abuf, sizeof(abuf), 469 NULL, 0, niflags) == 0), 470 (stdout, ";; Querying server (# %d) address = %s\n", 471 ns + 1, abuf)); 472 473 474 if (v_circuit) { 475 /* Use VC; at most one attempt per server. */ 476 tries = statp->retry; 477 n = send_vc(statp, buf, buflen, ans, anssiz, &terrno, 478 ns); 479 if (n < 0) 480 goto fail; 481 if (n == 0) 482 goto next_ns; 483 resplen = n; 484 } else { 485 /* Use datagrams. */ 486 n = send_dg(statp, buf, buflen, ans, anssiz, &terrno, 487 ns, tries, &v_circuit, &gotsomewhere); 488 if (n < 0) 489 goto fail; 490 if (n == 0) 491 goto next_ns; 492 if (v_circuit) 493 goto same_ns; 494 resplen = n; 495 } 496 497 Dprint((statp->options & RES_DEBUG) || 498 ((statp->pfcode & RES_PRF_REPLY) && 499 (statp->pfcode & RES_PRF_HEAD1)), 500 (stdout, ";; got answer:\n")); 501 502 DprintQ((statp->options & RES_DEBUG) || 503 (statp->pfcode & RES_PRF_REPLY), 504 (stdout, "%s", ""), 505 ans, (resplen > anssiz) ? anssiz : resplen); 506 507 /* 508 * If we have temporarily opened a virtual circuit, 509 * or if we haven't been asked to keep a socket open, 510 * close the socket. 511 */ 512 if ((v_circuit && (statp->options & RES_USEVC) == 0U) || 513 (statp->options & RES_STAYOPEN) == 0U) { 514 res_nclose(statp); 515 } 516 if (statp->rhook) { 517 int done = 0, loops = 0; 518 519 do { 520 res_sendhookact act; 521 522 act = (*statp->rhook)(nsap, buf, buflen, 523 ans, anssiz, &resplen); 524 switch (act) { 525 case res_goahead: 526 case res_done: 527 done = 1; 528 break; 529 case res_nextns: 530 res_nclose(statp); 531 goto next_ns; 532 case res_modified: 533 /* give the hook another try */ 534 if (++loops < 42) /*doug adams*/ 535 break; 536 /*FALLTHROUGH*/ 537 case res_error: 538 /*FALLTHROUGH*/ 539 default: 540 goto fail; 541 } 542 } while (!done); 543 544 } 545 return (resplen); 546 next_ns: ; 547 } /*foreach ns*/ 548 } /*foreach retry*/ 549 res_nclose(statp); 550 if (!v_circuit) { 551 if (!gotsomewhere) 552 errno = ECONNREFUSED; /*%< no nameservers found */ 553 else 554 errno = ETIMEDOUT; /*%< no answer obtained */ 555 } else 556 errno = terrno; 557 return (-1); 558 fail: 559 res_nclose(statp); 560 return (-1); 561 } 562 563 /* Private */ 564 565 static int 566 get_salen(sa) 567 const struct sockaddr *sa; 568 { 569 570 #ifdef HAVE_SA_LEN 571 /* There are people do not set sa_len. Be forgiving to them. */ 572 if (sa->sa_len) 573 return (sa->sa_len); 574 #endif 575 576 if (sa->sa_family == AF_INET) 577 return (sizeof(struct sockaddr_in)); 578 else if (sa->sa_family == AF_INET6) 579 return (sizeof(struct sockaddr_in6)); 580 else 581 return (0); /*%< unknown, die on connect */ 582 } 583 584 /*% 585 * pick appropriate nsaddr_list for use. see res_init() for initialization. 586 */ 587 static struct sockaddr * 588 get_nsaddr(statp, n) 589 res_state statp; 590 size_t n; 591 { 592 593 if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) { 594 /* 595 * - EXT(statp).ext->nsaddrs[n] holds an address that is larger 596 * than struct sockaddr, and 597 * - user code did not update statp->nsaddr_list[n]. 598 */ 599 return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n]; 600 } else { 601 /* 602 * - user code updated statp->nsaddr_list[n], or 603 * - statp->nsaddr_list[n] has the same content as 604 * EXT(statp).ext->nsaddrs[n]. 605 */ 606 return (struct sockaddr *)(void *)&statp->nsaddr_list[n]; 607 } 608 } 609 610 static int 611 send_vc(res_state statp, 612 const u_char *buf, int buflen, u_char *ans, int anssiz, 613 int *terrno, int ns) 614 { 615 const HEADER *hp = (const HEADER *)(const void *)buf; 616 HEADER *anhp = (HEADER *)(void *)ans; 617 struct sockaddr *nsap; 618 int nsaplen; 619 int truncating, connreset, resplen, n; 620 struct iovec iov[2]; 621 u_short len; 622 u_char *cp; 623 void *tmp; 624 #ifdef SO_NOSIGPIPE 625 int on = 1; 626 #endif 627 628 nsap = get_nsaddr(statp, (size_t)ns); 629 nsaplen = get_salen(nsap); 630 631 connreset = 0; 632 same_ns: 633 truncating = 0; 634 635 /* Are we still talking to whom we want to talk to? */ 636 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) { 637 struct sockaddr_storage peer; 638 ISC_SOCKLEN_T size = sizeof peer; 639 640 if (getpeername(statp->_vcsock, 641 (struct sockaddr *)(void *)&peer, &size) < 0 || 642 !sock_eq((struct sockaddr *)(void *)&peer, nsap)) { 643 res_nclose(statp); 644 statp->_flags &= ~RES_F_VC; 645 } 646 } 647 648 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) { 649 if (statp->_vcsock >= 0) 650 res_nclose(statp); 651 652 statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM, 0); 653 if (statp->_vcsock > highestFD) { 654 res_nclose(statp); 655 errno = ENOTSOCK; 656 } 657 if (statp->_vcsock < 0) { 658 switch (errno) { 659 case EPROTONOSUPPORT: 660 #ifdef EPFNOSUPPORT 661 case EPFNOSUPPORT: 662 #endif 663 case EAFNOSUPPORT: 664 Perror(statp, stderr, "socket(vc)", errno); 665 return (0); 666 default: 667 *terrno = errno; 668 Perror(statp, stderr, "socket(vc)", errno); 669 return (-1); 670 } 671 } 672 #ifdef SO_NOSIGPIPE 673 /* 674 * Disable generation of SIGPIPE when writing to a closed 675 * socket. Write should return -1 and set errno to EPIPE 676 * instead. 677 * 678 * Push on even if setsockopt(SO_NOSIGPIPE) fails. 679 */ 680 (void)setsockopt(statp->_vcsock, SOL_SOCKET, SO_NOSIGPIPE, &on, 681 sizeof(on)); 682 #endif 683 errno = 0; 684 if (connect(statp->_vcsock, nsap, (socklen_t)nsaplen) < 0) { 685 *terrno = errno; 686 Aerror(statp, stderr, "connect/vc", errno, nsap, 687 nsaplen); 688 res_nclose(statp); 689 return (0); 690 } 691 statp->_flags |= RES_F_VC; 692 } 693 694 /* 695 * Send length & message 696 */ 697 ns_put16((u_short)buflen, (u_char*)(void *)&len); 698 iov[0] = evConsIovec(&len, INT16SZ); 699 DE_CONST(buf, tmp); 700 iov[1] = evConsIovec(tmp, (size_t)buflen); 701 if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) { 702 *terrno = errno; 703 Perror(statp, stderr, "write failed", errno); 704 res_nclose(statp); 705 return (0); 706 } 707 /* 708 * Receive length & response 709 */ 710 read_len: 711 cp = ans; 712 len = INT16SZ; 713 while ((n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0) { 714 cp += n; 715 if ((len -= n) == 0) 716 break; 717 } 718 if (n <= 0) { 719 *terrno = errno; 720 Perror(statp, stderr, "read failed", errno); 721 res_nclose(statp); 722 /* 723 * A long running process might get its TCP 724 * connection reset if the remote server was 725 * restarted. Requery the server instead of 726 * trying a new one. When there is only one 727 * server, this means that a query might work 728 * instead of failing. We only allow one reset 729 * per query to prevent looping. 730 */ 731 if (*terrno == ECONNRESET && !connreset) { 732 connreset = 1; 733 res_nclose(statp); 734 goto same_ns; 735 } 736 res_nclose(statp); 737 return (0); 738 } 739 resplen = ns_get16(ans); 740 if (resplen > anssiz) { 741 Dprint(statp->options & RES_DEBUG, 742 (stdout, ";; response truncated\n") 743 ); 744 truncating = 1; 745 len = anssiz; 746 } else 747 len = resplen; 748 if (len < HFIXEDSZ) { 749 /* 750 * Undersized message. 751 */ 752 Dprint(statp->options & RES_DEBUG, 753 (stdout, ";; undersized: %d\n", len)); 754 *terrno = EMSGSIZE; 755 res_nclose(statp); 756 return (0); 757 } 758 cp = ans; 759 while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0){ 760 cp += n; 761 len -= n; 762 } 763 if (n <= 0) { 764 *terrno = errno; 765 Perror(statp, stderr, "read(vc)", errno); 766 res_nclose(statp); 767 return (0); 768 } 769 if (truncating) { 770 /* 771 * Flush rest of answer so connection stays in synch. 772 */ 773 anhp->tc = 1; 774 len = resplen - anssiz; 775 while (len != 0) { 776 char junk[PACKETSZ]; 777 778 n = read(statp->_vcsock, junk, 779 (len > sizeof junk) ? sizeof junk : len); 780 if (n > 0) 781 len -= n; 782 else 783 break; 784 } 785 } 786 /* 787 * If the calling applicating has bailed out of 788 * a previous call and failed to arrange to have 789 * the circuit closed or the server has got 790 * itself confused, then drop the packet and 791 * wait for the correct one. 792 */ 793 if (hp->id != anhp->id) { 794 DprintQ((statp->options & RES_DEBUG) || 795 (statp->pfcode & RES_PRF_REPLY), 796 (stdout, ";; old answer (unexpected):\n"), 797 ans, (resplen > anssiz) ? anssiz: resplen); 798 goto read_len; 799 } 800 801 /* 802 * All is well, or the error is fatal. Signal that the 803 * next nameserver ought not be tried. 804 */ 805 return (resplen); 806 } 807 808 static int 809 send_dg(res_state statp, const u_char *buf, int buflen, u_char *ans, 810 int anssiz, int *terrno, int ns, int tries, int *v_circuit, 811 int *gotsomewhere) 812 { 813 const HEADER *hp = (const HEADER *)(const void *)buf; 814 HEADER *anhp = (HEADER *)(void *)ans; 815 const struct sockaddr *nsap; 816 int nsaplen; 817 struct timespec now, timeout, finish; 818 struct sockaddr_storage from; 819 ISC_SOCKLEN_T fromlen; 820 int resplen, seconds, n, s; 821 #ifdef USE_POLL 822 int polltimeout; 823 struct pollfd pollfd; 824 #else 825 fd_set dsmask; 826 #endif 827 828 nsap = get_nsaddr(statp, (size_t)ns); 829 nsaplen = get_salen(nsap); 830 if (EXT(statp).nssocks[ns] == -1) { 831 EXT(statp).nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM, 0); 832 if (EXT(statp).nssocks[ns] > highestFD) { 833 res_nclose(statp); 834 errno = ENOTSOCK; 835 } 836 if (EXT(statp).nssocks[ns] < 0) { 837 switch (errno) { 838 case EPROTONOSUPPORT: 839 #ifdef EPFNOSUPPORT 840 case EPFNOSUPPORT: 841 #endif 842 case EAFNOSUPPORT: 843 Perror(statp, stderr, "socket(dg)", errno); 844 return (0); 845 default: 846 *terrno = errno; 847 Perror(statp, stderr, "socket(dg)", errno); 848 return (-1); 849 } 850 } 851 #ifndef CANNOT_CONNECT_DGRAM 852 /* 853 * On a 4.3BSD+ machine (client and server, 854 * actually), sending to a nameserver datagram 855 * port with no nameserver will cause an 856 * ICMP port unreachable message to be returned. 857 * If our datagram socket is "connected" to the 858 * server, we get an ECONNREFUSED error on the next 859 * socket operation, and select returns if the 860 * error message is received. We can thus detect 861 * the absence of a nameserver without timing out. 862 */ 863 if (connect(EXT(statp).nssocks[ns], nsap, (socklen_t)nsaplen) < 0) { 864 Aerror(statp, stderr, "connect(dg)", errno, nsap, 865 nsaplen); 866 res_nclose(statp); 867 return (0); 868 } 869 #endif /* !CANNOT_CONNECT_DGRAM */ 870 Dprint(statp->options & RES_DEBUG, 871 (stdout, ";; new DG socket\n")) 872 } 873 s = EXT(statp).nssocks[ns]; 874 #ifndef CANNOT_CONNECT_DGRAM 875 if (send(s, (const char*)buf, (size_t)buflen, 0) != buflen) { 876 Perror(statp, stderr, "send", errno); 877 res_nclose(statp); 878 return (0); 879 } 880 #else /* !CANNOT_CONNECT_DGRAM */ 881 if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) 882 { 883 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); 884 res_nclose(statp); 885 return (0); 886 } 887 #endif /* !CANNOT_CONNECT_DGRAM */ 888 889 /* 890 * Wait for reply. 891 */ 892 seconds = (statp->retrans << tries); 893 if (ns > 0) 894 seconds /= statp->nscount; 895 if (seconds <= 0) 896 seconds = 1; 897 now = evNowTime(); 898 timeout = evConsTime((long)seconds, 0L); 899 finish = evAddTime(now, timeout); 900 goto nonow; 901 wait: 902 now = evNowTime(); 903 nonow: 904 #ifndef USE_POLL 905 FD_ZERO(&dsmask); 906 FD_SET(s, &dsmask); 907 if (evCmpTime(finish, now) > 0) 908 timeout = evSubTime(finish, now); 909 else 910 timeout = evConsTime(0L, 0L); 911 n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL); 912 #else 913 timeout = evSubTime(finish, now); 914 if (timeout.tv_sec < 0) 915 timeout = evConsTime(0L, 0L); 916 polltimeout = 1000*timeout.tv_sec + 917 timeout.tv_nsec/1000000; 918 pollfd.fd = s; 919 pollfd.events = POLLRDNORM; 920 n = poll(&pollfd, 1, polltimeout); 921 #endif /* USE_POLL */ 922 923 if (n == 0) { 924 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); 925 *gotsomewhere = 1; 926 return (0); 927 } 928 if (n < 0) { 929 if (errno == EINTR) 930 goto wait; 931 #ifndef USE_POLL 932 Perror(statp, stderr, "select", errno); 933 #else 934 Perror(statp, stderr, "poll", errno); 935 #endif /* USE_POLL */ 936 res_nclose(statp); 937 return (0); 938 } 939 errno = 0; 940 fromlen = sizeof(from); 941 resplen = recvfrom(s, (char*)ans, (size_t)anssiz,0, 942 (struct sockaddr *)(void *)&from, &fromlen); 943 if (resplen <= 0) { 944 Perror(statp, stderr, "recvfrom", errno); 945 res_nclose(statp); 946 return (0); 947 } 948 *gotsomewhere = 1; 949 if (resplen < HFIXEDSZ) { 950 /* 951 * Undersized message. 952 */ 953 Dprint(statp->options & RES_DEBUG, 954 (stdout, ";; undersized: %d\n", 955 resplen)); 956 *terrno = EMSGSIZE; 957 res_nclose(statp); 958 return (0); 959 } 960 if (hp->id != anhp->id) { 961 /* 962 * response from old query, ignore it. 963 * XXX - potential security hazard could 964 * be detected here. 965 */ 966 DprintQ((statp->options & RES_DEBUG) || 967 (statp->pfcode & RES_PRF_REPLY), 968 (stdout, ";; old answer:\n"), 969 ans, (resplen > anssiz) ? anssiz : resplen); 970 goto wait; 971 } 972 if (!(statp->options & RES_INSECURE1) && 973 !res_ourserver_p(statp, (struct sockaddr *)(void *)&from)) { 974 /* 975 * response from wrong server? ignore it. 976 * XXX - potential security hazard could 977 * be detected here. 978 */ 979 DprintQ((statp->options & RES_DEBUG) || 980 (statp->pfcode & RES_PRF_REPLY), 981 (stdout, ";; not our server:\n"), 982 ans, (resplen > anssiz) ? anssiz : resplen); 983 goto wait; 984 } 985 #ifdef RES_USE_EDNS0 986 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) { 987 /* 988 * Do not retry if the server do not understand EDNS0. 989 * The case has to be captured here, as FORMERR packet do not 990 * carry query section, hence res_queriesmatch() returns 0. 991 */ 992 DprintQ(statp->options & RES_DEBUG, 993 (stdout, "server rejected query with EDNS0:\n"), 994 ans, (resplen > anssiz) ? anssiz : resplen); 995 /* record the error */ 996 statp->_flags |= RES_F_EDNS0ERR; 997 res_nclose(statp); 998 return (0); 999 } 1000 #endif 1001 if (!(statp->options & RES_INSECURE2) && 1002 !res_queriesmatch(buf, buf + buflen, 1003 ans, ans + anssiz)) { 1004 /* 1005 * response contains wrong query? ignore it. 1006 * XXX - potential security hazard could 1007 * be detected here. 1008 */ 1009 DprintQ((statp->options & RES_DEBUG) || 1010 (statp->pfcode & RES_PRF_REPLY), 1011 (stdout, ";; wrong query name:\n"), 1012 ans, (resplen > anssiz) ? anssiz : resplen); 1013 goto wait; 1014 } 1015 if (anhp->rcode == SERVFAIL || 1016 anhp->rcode == NOTIMP || 1017 anhp->rcode == REFUSED) { 1018 DprintQ(statp->options & RES_DEBUG, 1019 (stdout, "server rejected query:\n"), 1020 ans, (resplen > anssiz) ? anssiz : resplen); 1021 res_nclose(statp); 1022 /* don't retry if called from dig */ 1023 if (!statp->pfcode) 1024 return (0); 1025 } 1026 if (!(statp->options & RES_IGNTC) && anhp->tc) { 1027 /* 1028 * To get the rest of answer, 1029 * use TCP with same server. 1030 */ 1031 Dprint(statp->options & RES_DEBUG, 1032 (stdout, ";; truncated answer\n")); 1033 *v_circuit = 1; 1034 res_nclose(statp); 1035 return (1); 1036 } 1037 /* 1038 * All is well, or the error is fatal. Signal that the 1039 * next nameserver ought not be tried. 1040 */ 1041 return (resplen); 1042 } 1043 1044 static void 1045 Aerror(const res_state statp, FILE *file, const char *string, int error, 1046 const struct sockaddr *address, int alen) 1047 { 1048 int save = errno; 1049 char hbuf[NI_MAXHOST]; 1050 char sbuf[NI_MAXSERV]; 1051 1052 alen = alen; 1053 1054 if ((statp->options & RES_DEBUG) != 0U) { 1055 if (getnameinfo(address, (socklen_t)alen, hbuf, sizeof(hbuf), 1056 sbuf, sizeof(sbuf), niflags)) { 1057 strncpy(hbuf, "?", sizeof(hbuf) - 1); 1058 hbuf[sizeof(hbuf) - 1] = '\0'; 1059 strncpy(sbuf, "?", sizeof(sbuf) - 1); 1060 sbuf[sizeof(sbuf) - 1] = '\0'; 1061 } 1062 fprintf(file, "res_send: %s ([%s].%s): %s\n", 1063 string, hbuf, sbuf, strerror(error)); 1064 } 1065 errno = save; 1066 } 1067 1068 static void 1069 Perror(const res_state statp, FILE *file, const char *string, int error) { 1070 int save = errno; 1071 1072 if ((statp->options & RES_DEBUG) != 0U) 1073 fprintf(file, "res_send: %s: %s\n", 1074 string, strerror(error)); 1075 errno = save; 1076 } 1077 1078 static int 1079 sock_eq(struct sockaddr *a, struct sockaddr *b) { 1080 struct sockaddr_in *a4, *b4; 1081 struct sockaddr_in6 *a6, *b6; 1082 1083 if (a->sa_family != b->sa_family) 1084 return 0; 1085 switch (a->sa_family) { 1086 case AF_INET: 1087 a4 = (struct sockaddr_in *)(void *)a; 1088 b4 = (struct sockaddr_in *)(void *)b; 1089 return a4->sin_port == b4->sin_port && 1090 a4->sin_addr.s_addr == b4->sin_addr.s_addr; 1091 case AF_INET6: 1092 a6 = (struct sockaddr_in6 *)(void *)a; 1093 b6 = (struct sockaddr_in6 *)(void *)b; 1094 return a6->sin6_port == b6->sin6_port && 1095 #ifdef HAVE_SIN6_SCOPE_ID 1096 a6->sin6_scope_id == b6->sin6_scope_id && 1097 #endif 1098 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr); 1099 default: 1100 return 0; 1101 } 1102 } 1103 1104 #if defined(NEED_PSELECT) && !defined(USE_POLL) 1105 /* XXX needs to move to the porting library. */ 1106 static int 1107 pselect(int nfds, void *rfds, void *wfds, void *efds, 1108 struct timespec *tsp, const sigset_t *sigmask) 1109 { 1110 struct timeval tv, *tvp; 1111 sigset_t sigs; 1112 int n; 1113 1114 if (tsp) { 1115 tvp = &tv; 1116 tv = evTimeVal(*tsp); 1117 } else 1118 tvp = NULL; 1119 if (sigmask) 1120 sigprocmask(SIG_SETMASK, sigmask, &sigs); 1121 n = select(nfds, rfds, wfds, efds, tvp); 1122 if (sigmask) 1123 sigprocmask(SIG_SETMASK, &sigs, NULL); 1124 if (tsp) 1125 *tsp = evTimeSpec(tv); 1126 return (n); 1127 } 1128 #endif 1129