1 /* 2 * Copyright (c) 1985, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 /* 31 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 32 * 33 * Permission to use, copy, modify, and distribute this software for any 34 * purpose with or without fee is hereby granted, provided that the above 35 * copyright notice and this permission notice appear in all copies, and that 36 * the name of Digital Equipment Corporation not be used in advertising or 37 * publicity pertaining to distribution of the document or software without 38 * specific, written prior permission. 39 * 40 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 41 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 42 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 43 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 44 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 45 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 46 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 47 * SOFTWARE. 48 */ 49 50 /* 51 * Copyright (c) 2005 by Internet Systems Consortium, Inc. ("ISC") 52 * Portions Copyright (c) 1996-1999 by Internet Software Consortium. 53 * 54 * Permission to use, copy, modify, and distribute this software for any 55 * purpose with or without fee is hereby granted, provided that the above 56 * copyright notice and this permission notice appear in all copies. 57 * 58 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 59 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 60 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 61 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 62 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 63 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 64 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 65 */ 66 67 #if defined(LIBC_SCCS) && !defined(lint) 68 static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93"; 69 static const char rcsid[] = "$Id: res_send.c,v 1.9.18.10 2008/01/27 02:06:26 marka Exp $"; 70 #endif /* LIBC_SCCS and not lint */ 71 #include <sys/cdefs.h> 72 __FBSDID("$FreeBSD$"); 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) 129 static const int highestFD = FD_SETSIZE - 1; 130 #endif 131 132 /* Forward. */ 133 134 static int get_salen(const struct sockaddr *); 135 static struct sockaddr * get_nsaddr(res_state, size_t); 136 static int send_vc(res_state, const u_char *, int, 137 u_char *, int, int *, int); 138 static 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 *); 145 static void Aerror(const res_state, FILE *, const char *, int, 146 const struct sockaddr *, int); 147 static void Perror(const res_state, FILE *, const char *, int); 148 static int sock_eq(struct sockaddr *, struct sockaddr *); 149 #if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE) 150 static int pselect(int, void *, void *, void *, 151 struct timespec *, 152 const sigset_t *); 153 #endif 154 void res_pquery(const res_state, const u_char *, int, FILE *); 155 156 static 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 */ 170 int 171 res_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 */ 225 int 226 res_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 */ 263 int 264 res_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 } 300 301 int 302 res_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 */ 575 576 static int 577 get_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 */ 598 static struct sockaddr * 599 get_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 } 620 621 static int 622 send_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 } 821 822 static int 823 send_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 1097 static void 1098 Aerror(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 alen = alen; 1106 1107 if ((statp->options & RES_DEBUG) != 0U) { 1108 if (getnameinfo(address, alen, hbuf, sizeof(hbuf), 1109 sbuf, sizeof(sbuf), niflags)) { 1110 strncpy(hbuf, "?", sizeof(hbuf) - 1); 1111 hbuf[sizeof(hbuf) - 1] = '\0'; 1112 strncpy(sbuf, "?", sizeof(sbuf) - 1); 1113 sbuf[sizeof(sbuf) - 1] = '\0'; 1114 } 1115 fprintf(file, "res_send: %s ([%s].%s): %s\n", 1116 string, hbuf, sbuf, strerror(error)); 1117 } 1118 errno = save; 1119 } 1120 1121 static void 1122 Perror(const res_state statp, FILE *file, const char *string, int error) { 1123 int save = errno; 1124 1125 if ((statp->options & RES_DEBUG) != 0U) 1126 fprintf(file, "res_send: %s: %s\n", 1127 string, strerror(error)); 1128 errno = save; 1129 } 1130 1131 static int 1132 sock_eq(struct sockaddr *a, struct sockaddr *b) { 1133 struct sockaddr_in *a4, *b4; 1134 struct sockaddr_in6 *a6, *b6; 1135 1136 if (a->sa_family != b->sa_family) 1137 return 0; 1138 switch (a->sa_family) { 1139 case AF_INET: 1140 a4 = (struct sockaddr_in *)a; 1141 b4 = (struct sockaddr_in *)b; 1142 return a4->sin_port == b4->sin_port && 1143 a4->sin_addr.s_addr == b4->sin_addr.s_addr; 1144 case AF_INET6: 1145 a6 = (struct sockaddr_in6 *)a; 1146 b6 = (struct sockaddr_in6 *)b; 1147 return a6->sin6_port == b6->sin6_port && 1148 #ifdef HAVE_SIN6_SCOPE_ID 1149 a6->sin6_scope_id == b6->sin6_scope_id && 1150 #endif 1151 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr); 1152 default: 1153 return 0; 1154 } 1155 } 1156 1157 #if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE) 1158 /* XXX needs to move to the porting library. */ 1159 static int 1160 pselect(int nfds, void *rfds, void *wfds, void *efds, 1161 struct timespec *tsp, const sigset_t *sigmask) 1162 { 1163 struct timeval tv, *tvp; 1164 sigset_t sigs; 1165 int n; 1166 1167 if (tsp) { 1168 tvp = &tv; 1169 tv = evTimeVal(*tsp); 1170 } else 1171 tvp = NULL; 1172 if (sigmask) 1173 sigprocmask(SIG_SETMASK, sigmask, &sigs); 1174 n = select(nfds, rfds, wfds, efds, tvp); 1175 if (sigmask) 1176 sigprocmask(SIG_SETMASK, &sigs, NULL); 1177 if (tsp) 1178 *tsp = evTimeSpec(tv); 1179 return (n); 1180 } 1181 #endif 1182