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 1.9.18.8 2006/10/16 23:00:58 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, try, 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 (try = 0; try < statp->retry; try++) { 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 try = 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, try, &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; 635 636 nsap = get_nsaddr(statp, ns); 637 nsaplen = get_salen(nsap); 638 639 connreset = 0; 640 same_ns: 641 truncating = 0; 642 643 /* Are we still talking to whom we want to talk to? */ 644 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) { 645 struct sockaddr_storage peer; 646 ISC_SOCKLEN_T size = sizeof peer; 647 648 if (_getpeername(statp->_vcsock, 649 (struct sockaddr *)&peer, &size) < 0 || 650 !sock_eq((struct sockaddr *)&peer, nsap)) { 651 res_nclose(statp); 652 statp->_flags &= ~RES_F_VC; 653 } 654 } 655 656 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) { 657 if (statp->_vcsock >= 0) 658 res_nclose(statp); 659 660 statp->_vcsock = _socket(nsap->sa_family, SOCK_STREAM, 0); 661 #if !defined(USE_POLL) && !defined(USE_KQUEUE) 662 if (statp->_vcsock > highestFD) { 663 res_nclose(statp); 664 errno = ENOTSOCK; 665 } 666 #endif 667 if (statp->_vcsock < 0) { 668 switch (errno) { 669 case EPROTONOSUPPORT: 670 #ifdef EPFNOSUPPORT 671 case EPFNOSUPPORT: 672 #endif 673 case EAFNOSUPPORT: 674 Perror(statp, stderr, "socket(vc)", errno); 675 return (0); 676 default: 677 *terrno = errno; 678 Perror(statp, stderr, "socket(vc)", errno); 679 return (-1); 680 } 681 } 682 errno = 0; 683 if (_connect(statp->_vcsock, nsap, nsaplen) < 0) { 684 *terrno = errno; 685 Aerror(statp, stderr, "connect/vc", errno, nsap, 686 nsaplen); 687 res_nclose(statp); 688 return (0); 689 } 690 statp->_flags |= RES_F_VC; 691 } 692 693 /* 694 * Send length & message 695 */ 696 ns_put16((u_short)buflen, (u_char*)&len); 697 iov[0] = evConsIovec(&len, INT16SZ); 698 DE_CONST(buf, tmp); 699 iov[1] = evConsIovec(tmp, buflen); 700 if (_writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) { 701 *terrno = errno; 702 Perror(statp, stderr, "write failed", errno); 703 res_nclose(statp); 704 return (0); 705 } 706 /* 707 * Receive length & response 708 */ 709 read_len: 710 cp = ans; 711 len = INT16SZ; 712 while ((n = _read(statp->_vcsock, (char *)cp, (int)len)) > 0) { 713 cp += n; 714 if ((len -= n) == 0) 715 break; 716 } 717 if (n <= 0) { 718 *terrno = errno; 719 Perror(statp, stderr, "read failed", errno); 720 res_nclose(statp); 721 /* 722 * A long running process might get its TCP 723 * connection reset if the remote server was 724 * restarted. Requery the server instead of 725 * trying a new one. When there is only one 726 * server, this means that a query might work 727 * instead of failing. We only allow one reset 728 * per query to prevent looping. 729 */ 730 if (*terrno == ECONNRESET && !connreset) { 731 connreset = 1; 732 res_nclose(statp); 733 goto same_ns; 734 } 735 res_nclose(statp); 736 return (0); 737 } 738 resplen = ns_get16(ans); 739 if (resplen > anssiz) { 740 Dprint(statp->options & RES_DEBUG, 741 (stdout, ";; response truncated\n") 742 ); 743 truncating = 1; 744 len = anssiz; 745 } else 746 len = resplen; 747 if (len < HFIXEDSZ) { 748 /* 749 * Undersized message. 750 */ 751 Dprint(statp->options & RES_DEBUG, 752 (stdout, ";; undersized: %d\n", len)); 753 *terrno = EMSGSIZE; 754 res_nclose(statp); 755 return (0); 756 } 757 cp = ans; 758 while (len != 0 && 759 (n = _read(statp->_vcsock, (char *)cp, (int)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, 810 #ifdef USE_KQUEUE 811 int kq, 812 #endif 813 const u_char *buf, int buflen, u_char *ans, 814 int anssiz, int *terrno, int ns, int try, int *v_circuit, 815 int *gotsomewhere) 816 { 817 const HEADER *hp = (const HEADER *) buf; 818 HEADER *anhp = (HEADER *) ans; 819 const struct sockaddr *nsap; 820 int nsaplen; 821 struct timespec now, timeout, finish; 822 struct sockaddr_storage from; 823 ISC_SOCKLEN_T fromlen; 824 int resplen, seconds, n, s; 825 #ifdef USE_KQUEUE 826 struct kevent kv; 827 #else 828 #ifdef USE_POLL 829 int polltimeout; 830 struct pollfd pollfd; 831 #else 832 fd_set dsmask; 833 #endif 834 #endif 835 836 nsap = get_nsaddr(statp, ns); 837 nsaplen = get_salen(nsap); 838 if (EXT(statp).nssocks[ns] == -1) { 839 EXT(statp).nssocks[ns] = _socket(nsap->sa_family, 840 SOCK_DGRAM, 0); 841 #if !defined(USE_POLL) && !defined(USE_KQUEUE) 842 if (EXT(statp).nssocks[ns] > highestFD) { 843 res_nclose(statp); 844 errno = ENOTSOCK; 845 } 846 #endif 847 if (EXT(statp).nssocks[ns] < 0) { 848 switch (errno) { 849 case EPROTONOSUPPORT: 850 #ifdef EPFNOSUPPORT 851 case EPFNOSUPPORT: 852 #endif 853 case EAFNOSUPPORT: 854 Perror(statp, stderr, "socket(dg)", errno); 855 return (0); 856 default: 857 *terrno = errno; 858 Perror(statp, stderr, "socket(dg)", errno); 859 return (-1); 860 } 861 } 862 #ifndef CANNOT_CONNECT_DGRAM 863 /* 864 * On a 4.3BSD+ machine (client and server, 865 * actually), sending to a nameserver datagram 866 * port with no nameserver will cause an 867 * ICMP port unreachable message to be returned. 868 * If our datagram socket is "connected" to the 869 * server, we get an ECONNREFUSED error on the next 870 * socket operation, and select returns if the 871 * error message is received. We can thus detect 872 * the absence of a nameserver without timing out. 873 * 874 * When the option "insecure1" is specified, we'd 875 * rather expect to see responses from an "unknown" 876 * address. In order to let the kernel accept such 877 * responses, do not connect the socket here. 878 * XXX: or do we need an explicit option to disable 879 * connecting? 880 */ 881 if (!(statp->options & RES_INSECURE1) && 882 _connect(EXT(statp).nssocks[ns], nsap, nsaplen) < 0) { 883 Aerror(statp, stderr, "connect(dg)", errno, nsap, 884 nsaplen); 885 res_nclose(statp); 886 return (0); 887 } 888 #endif /* !CANNOT_CONNECT_DGRAM */ 889 Dprint(statp->options & RES_DEBUG, 890 (stdout, ";; new DG socket\n")) 891 } 892 s = EXT(statp).nssocks[ns]; 893 #ifndef CANNOT_CONNECT_DGRAM 894 if (statp->options & RES_INSECURE1) { 895 if (_sendto(s, 896 (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) { 897 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); 898 res_nclose(statp); 899 return (0); 900 } 901 } else if (send(s, (const char*)buf, buflen, 0) != buflen) { 902 Perror(statp, stderr, "send", errno); 903 res_nclose(statp); 904 return (0); 905 } 906 #else /* !CANNOT_CONNECT_DGRAM */ 907 if (_sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) 908 { 909 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); 910 res_nclose(statp); 911 return (0); 912 } 913 #endif /* !CANNOT_CONNECT_DGRAM */ 914 915 /* 916 * Wait for reply. 917 */ 918 seconds = (statp->retrans << try); 919 if (ns > 0) 920 seconds /= statp->nscount; 921 if (seconds <= 0) 922 seconds = 1; 923 now = evNowTime(); 924 timeout = evConsTime(seconds, 0); 925 finish = evAddTime(now, timeout); 926 goto nonow; 927 wait: 928 now = evNowTime(); 929 nonow: 930 #ifndef USE_POLL 931 if (evCmpTime(finish, now) > 0) 932 timeout = evSubTime(finish, now); 933 else 934 timeout = evConsTime(0, 0); 935 #ifdef USE_KQUEUE 936 EV_SET(&kv, s, EVFILT_READ, EV_ADD | EV_ONESHOT, 0, 0, 0); 937 n = _kevent(kq, &kv, 1, &kv, 1, &timeout); 938 #else 939 FD_ZERO(&dsmask); 940 FD_SET(s, &dsmask); 941 n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL); 942 #endif 943 #else 944 timeout = evSubTime(finish, now); 945 if (timeout.tv_sec < 0) 946 timeout = evConsTime(0, 0); 947 polltimeout = 1000*timeout.tv_sec + 948 timeout.tv_nsec/1000000; 949 pollfd.fd = s; 950 pollfd.events = POLLRDNORM; 951 n = poll(&pollfd, 1, polltimeout); 952 #endif /* USE_POLL */ 953 954 if (n == 0) { 955 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); 956 *gotsomewhere = 1; 957 return (0); 958 } 959 if (n < 0) { 960 if (errno == EINTR) 961 goto wait; 962 #ifdef USE_KQUEUE 963 Perror(statp, stderr, "kevent", errno); 964 #else 965 #ifndef USE_POLL 966 Perror(statp, stderr, "select", errno); 967 #else 968 Perror(statp, stderr, "poll", errno); 969 #endif /* USE_POLL */ 970 #endif 971 res_nclose(statp); 972 return (0); 973 } 974 #ifdef USE_KQUEUE 975 if (kv.ident != s) 976 goto wait; 977 #endif 978 errno = 0; 979 fromlen = sizeof(from); 980 resplen = _recvfrom(s, (char*)ans, anssiz,0, 981 (struct sockaddr *)&from, &fromlen); 982 if (resplen <= 0) { 983 Perror(statp, stderr, "recvfrom", errno); 984 res_nclose(statp); 985 return (0); 986 } 987 *gotsomewhere = 1; 988 if (resplen < HFIXEDSZ) { 989 /* 990 * Undersized message. 991 */ 992 Dprint(statp->options & RES_DEBUG, 993 (stdout, ";; undersized: %d\n", 994 resplen)); 995 *terrno = EMSGSIZE; 996 res_nclose(statp); 997 return (0); 998 } 999 if (hp->id != anhp->id) { 1000 /* 1001 * response from old query, ignore it. 1002 * XXX - potential security hazard could 1003 * be detected here. 1004 */ 1005 DprintQ((statp->options & RES_DEBUG) || 1006 (statp->pfcode & RES_PRF_REPLY), 1007 (stdout, ";; old answer:\n"), 1008 ans, (resplen > anssiz) ? anssiz : resplen); 1009 goto wait; 1010 } 1011 if (!(statp->options & RES_INSECURE1) && 1012 !res_ourserver_p(statp, (struct sockaddr *)&from)) { 1013 /* 1014 * response from wrong server? ignore it. 1015 * XXX - potential security hazard could 1016 * be detected here. 1017 */ 1018 DprintQ((statp->options & RES_DEBUG) || 1019 (statp->pfcode & RES_PRF_REPLY), 1020 (stdout, ";; not our server:\n"), 1021 ans, (resplen > anssiz) ? anssiz : resplen); 1022 goto wait; 1023 } 1024 #ifdef RES_USE_EDNS0 1025 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) { 1026 /* 1027 * Do not retry if the server do not understand EDNS0. 1028 * The case has to be captured here, as FORMERR packet do not 1029 * carry query section, hence res_queriesmatch() returns 0. 1030 */ 1031 DprintQ(statp->options & RES_DEBUG, 1032 (stdout, "server rejected query with EDNS0:\n"), 1033 ans, (resplen > anssiz) ? anssiz : resplen); 1034 /* record the error */ 1035 statp->_flags |= RES_F_EDNS0ERR; 1036 res_nclose(statp); 1037 return (0); 1038 } 1039 #endif 1040 if (!(statp->options & RES_INSECURE2) && 1041 !res_queriesmatch(buf, buf + buflen, 1042 ans, ans + anssiz)) { 1043 /* 1044 * response contains wrong query? ignore it. 1045 * XXX - potential security hazard could 1046 * be detected here. 1047 */ 1048 DprintQ((statp->options & RES_DEBUG) || 1049 (statp->pfcode & RES_PRF_REPLY), 1050 (stdout, ";; wrong query name:\n"), 1051 ans, (resplen > anssiz) ? anssiz : resplen); 1052 goto wait; 1053 } 1054 if (anhp->rcode == SERVFAIL || 1055 anhp->rcode == NOTIMP || 1056 anhp->rcode == REFUSED) { 1057 DprintQ(statp->options & RES_DEBUG, 1058 (stdout, "server rejected query:\n"), 1059 ans, (resplen > anssiz) ? anssiz : resplen); 1060 res_nclose(statp); 1061 /* don't retry if called from dig */ 1062 if (!statp->pfcode) 1063 return (0); 1064 } 1065 if (!(statp->options & RES_IGNTC) && anhp->tc) { 1066 /* 1067 * To get the rest of answer, 1068 * use TCP with same server. 1069 */ 1070 Dprint(statp->options & RES_DEBUG, 1071 (stdout, ";; truncated answer\n")); 1072 *v_circuit = 1; 1073 res_nclose(statp); 1074 return (1); 1075 } 1076 /* 1077 * All is well, or the error is fatal. Signal that the 1078 * next nameserver ought not be tried. 1079 */ 1080 return (resplen); 1081 } 1082 1083 static void 1084 Aerror(const res_state statp, FILE *file, const char *string, int error, 1085 const struct sockaddr *address, int alen) 1086 { 1087 int save = errno; 1088 char hbuf[NI_MAXHOST]; 1089 char sbuf[NI_MAXSERV]; 1090 1091 alen = alen; 1092 1093 if ((statp->options & RES_DEBUG) != 0U) { 1094 if (getnameinfo(address, alen, hbuf, sizeof(hbuf), 1095 sbuf, sizeof(sbuf), niflags)) { 1096 strncpy(hbuf, "?", sizeof(hbuf) - 1); 1097 hbuf[sizeof(hbuf) - 1] = '\0'; 1098 strncpy(sbuf, "?", sizeof(sbuf) - 1); 1099 sbuf[sizeof(sbuf) - 1] = '\0'; 1100 } 1101 fprintf(file, "res_send: %s ([%s].%s): %s\n", 1102 string, hbuf, sbuf, strerror(error)); 1103 } 1104 errno = save; 1105 } 1106 1107 static void 1108 Perror(const res_state statp, FILE *file, const char *string, int error) { 1109 int save = errno; 1110 1111 if ((statp->options & RES_DEBUG) != 0U) 1112 fprintf(file, "res_send: %s: %s\n", 1113 string, strerror(error)); 1114 errno = save; 1115 } 1116 1117 static int 1118 sock_eq(struct sockaddr *a, struct sockaddr *b) { 1119 struct sockaddr_in *a4, *b4; 1120 struct sockaddr_in6 *a6, *b6; 1121 1122 if (a->sa_family != b->sa_family) 1123 return 0; 1124 switch (a->sa_family) { 1125 case AF_INET: 1126 a4 = (struct sockaddr_in *)a; 1127 b4 = (struct sockaddr_in *)b; 1128 return a4->sin_port == b4->sin_port && 1129 a4->sin_addr.s_addr == b4->sin_addr.s_addr; 1130 case AF_INET6: 1131 a6 = (struct sockaddr_in6 *)a; 1132 b6 = (struct sockaddr_in6 *)b; 1133 return a6->sin6_port == b6->sin6_port && 1134 #ifdef HAVE_SIN6_SCOPE_ID 1135 a6->sin6_scope_id == b6->sin6_scope_id && 1136 #endif 1137 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr); 1138 default: 1139 return 0; 1140 } 1141 } 1142 1143 #if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE) 1144 /* XXX needs to move to the porting library. */ 1145 static int 1146 pselect(int nfds, void *rfds, void *wfds, void *efds, 1147 struct timespec *tsp, const sigset_t *sigmask) 1148 { 1149 struct timeval tv, *tvp; 1150 sigset_t sigs; 1151 int n; 1152 1153 if (tsp) { 1154 tvp = &tv; 1155 tv = evTimeVal(*tsp); 1156 } else 1157 tvp = NULL; 1158 if (sigmask) 1159 sigprocmask(SIG_SETMASK, sigmask, &sigs); 1160 n = select(nfds, rfds, wfds, efds, tvp); 1161 if (sigmask) 1162 sigprocmask(SIG_SETMASK, &sigs, NULL); 1163 if (tsp) 1164 *tsp = evTimeSpec(tv); 1165 return (n); 1166 } 1167 #endif 1168