1 /* $NetBSD: res_send.c,v 1.13 2007/03/30 20:23:05 ghen 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 1.9.18.8 2006/10/16 23:00:58 marka Exp"; 78 #else 79 __RCSID("$NetBSD: res_send.c,v 1.13 2007/03/30 20:23:05 ghen 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 #endif 144 145 /* Forward. */ 146 147 static int get_salen __P((const struct sockaddr *)); 148 static struct sockaddr * get_nsaddr __P((res_state, size_t)); 149 static int send_vc(res_state, const u_char *, int, 150 u_char *, int, int *, int); 151 static int send_dg(res_state, const u_char *, int, 152 u_char *, int, int *, int, int, 153 int *, int *); 154 static void Aerror(const res_state, FILE *, const char *, int, 155 const struct sockaddr *, int); 156 static void Perror(const res_state, FILE *, const char *, int); 157 static int sock_eq(struct sockaddr *, struct sockaddr *); 158 #if defined(NEED_PSELECT) && !defined(USE_POLL) 159 static int pselect(int, void *, void *, void *, 160 struct timespec *, 161 const sigset_t *); 162 #endif 163 void res_pquery(const res_state, const u_char *, int, FILE *); 164 165 static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV; 166 167 /* Public. */ 168 169 /*% 170 * looks up "ina" in _res.ns_addr_list[] 171 * 172 * returns: 173 *\li 0 : not found 174 *\li >0 : found 175 * 176 * author: 177 *\li paul vixie, 29may94 178 */ 179 int 180 res_ourserver_p(const res_state statp, const struct sockaddr *sa) { 181 const struct sockaddr_in *inp, *srv; 182 const struct sockaddr_in6 *in6p, *srv6; 183 int ns; 184 185 switch (sa->sa_family) { 186 case AF_INET: 187 inp = (const struct sockaddr_in *)(const void *)sa; 188 for (ns = 0; ns < statp->nscount; ns++) { 189 srv = (struct sockaddr_in *)(void *)get_nsaddr(statp, (size_t)ns); 190 if (srv->sin_family == inp->sin_family && 191 srv->sin_port == inp->sin_port && 192 (srv->sin_addr.s_addr == INADDR_ANY || 193 srv->sin_addr.s_addr == inp->sin_addr.s_addr)) 194 return (1); 195 } 196 break; 197 case AF_INET6: 198 if (EXT(statp).ext == NULL) 199 break; 200 in6p = (const struct sockaddr_in6 *)(const void *)sa; 201 for (ns = 0; ns < statp->nscount; ns++) { 202 srv6 = (struct sockaddr_in6 *)(void *)get_nsaddr(statp, (size_t)ns); 203 if (srv6->sin6_family == in6p->sin6_family && 204 srv6->sin6_port == in6p->sin6_port && 205 #ifdef HAVE_SIN6_SCOPE_ID 206 (srv6->sin6_scope_id == 0 || 207 srv6->sin6_scope_id == in6p->sin6_scope_id) && 208 #endif 209 (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) || 210 IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr))) 211 return (1); 212 } 213 break; 214 default: 215 break; 216 } 217 return (0); 218 } 219 220 /*% 221 * look for (name,type,class) in the query section of packet (buf,eom) 222 * 223 * requires: 224 *\li buf + HFIXEDSZ <= eom 225 * 226 * returns: 227 *\li -1 : format error 228 *\li 0 : not found 229 *\li >0 : found 230 * 231 * author: 232 *\li paul vixie, 29may94 233 */ 234 int 235 res_nameinquery(const char *name, int type, int class, 236 const u_char *buf, const u_char *eom) 237 { 238 const u_char *cp = buf + HFIXEDSZ; 239 int qdcount = ntohs(((const HEADER*)(const void *)buf)->qdcount); 240 241 while (qdcount-- > 0) { 242 char tname[MAXDNAME+1]; 243 int n, ttype, tclass; 244 245 n = dn_expand(buf, eom, cp, tname, sizeof tname); 246 if (n < 0) 247 return (-1); 248 cp += n; 249 if (cp + 2 * INT16SZ > eom) 250 return (-1); 251 ttype = ns_get16(cp); cp += INT16SZ; 252 tclass = ns_get16(cp); cp += INT16SZ; 253 if (ttype == type && tclass == class && 254 ns_samename(tname, name) == 1) 255 return (1); 256 } 257 return (0); 258 } 259 260 /*% 261 * is there a 1:1 mapping of (name,type,class) 262 * in (buf1,eom1) and (buf2,eom2)? 263 * 264 * returns: 265 *\li -1 : format error 266 *\li 0 : not a 1:1 mapping 267 *\li >0 : is a 1:1 mapping 268 * 269 * author: 270 *\li paul vixie, 29may94 271 */ 272 int 273 res_queriesmatch(const u_char *buf1, const u_char *eom1, 274 const u_char *buf2, const u_char *eom2) 275 { 276 const u_char *cp = buf1 + HFIXEDSZ; 277 int qdcount = ntohs(((const HEADER*)(const void *)buf1)->qdcount); 278 279 if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2) 280 return (-1); 281 282 /* 283 * Only header section present in replies to 284 * dynamic update packets. 285 */ 286 if ((((const HEADER *)(const void *)buf1)->opcode == ns_o_update) && 287 (((const HEADER *)(const void *)buf2)->opcode == ns_o_update)) 288 return (1); 289 290 if (qdcount != ntohs(((const HEADER*)(const void *)buf2)->qdcount)) 291 return (0); 292 while (qdcount-- > 0) { 293 char tname[MAXDNAME+1]; 294 int n, ttype, tclass; 295 296 n = dn_expand(buf1, eom1, cp, tname, sizeof tname); 297 if (n < 0) 298 return (-1); 299 cp += n; 300 if (cp + 2 * INT16SZ > eom1) 301 return (-1); 302 ttype = ns_get16(cp); cp += INT16SZ; 303 tclass = ns_get16(cp); cp += INT16SZ; 304 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) 305 return (0); 306 } 307 return (1); 308 } 309 310 int 311 res_nsend(res_state statp, 312 const u_char *buf, int buflen, u_char *ans, int anssiz) 313 { 314 int gotsomewhere, terrno, try, v_circuit, resplen, ns, n; 315 char abuf[NI_MAXHOST]; 316 317 /* No name servers or res_init() failure */ 318 if (statp->nscount == 0 || EXT(statp).ext == NULL) { 319 errno = ESRCH; 320 return (-1); 321 } 322 if (anssiz < HFIXEDSZ) { 323 errno = EINVAL; 324 return (-1); 325 } 326 DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY), 327 (stdout, ";; res_send()\n"), buf, buflen); 328 v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ; 329 gotsomewhere = 0; 330 terrno = ETIMEDOUT; 331 332 /* 333 * If the ns_addr_list in the resolver context has changed, then 334 * invalidate our cached copy and the associated timing data. 335 */ 336 if (EXT(statp).nscount != 0) { 337 int needclose = 0; 338 struct sockaddr_storage peer; 339 ISC_SOCKLEN_T peerlen; 340 341 if (EXT(statp).nscount != statp->nscount) 342 needclose++; 343 else 344 for (ns = 0; ns < statp->nscount; ns++) { 345 if (statp->nsaddr_list[ns].sin_family && 346 !sock_eq((struct sockaddr *)(void *)&statp->nsaddr_list[ns], 347 (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[ns])) { 348 needclose++; 349 break; 350 } 351 352 if (EXT(statp).nssocks[ns] == -1) 353 continue; 354 peerlen = sizeof(peer); 355 if (getsockname(EXT(statp).nssocks[ns], 356 (struct sockaddr *)(void *)&peer, &peerlen) < 0) { 357 needclose++; 358 break; 359 } 360 if (!sock_eq((struct sockaddr *)(void *)&peer, 361 get_nsaddr(statp, (size_t)ns))) { 362 needclose++; 363 break; 364 } 365 } 366 if (needclose) { 367 res_nclose(statp); 368 EXT(statp).nscount = 0; 369 } 370 } 371 372 /* 373 * Maybe initialize our private copy of the ns_addr_list. 374 */ 375 if (EXT(statp).nscount == 0) { 376 for (ns = 0; ns < statp->nscount; ns++) { 377 EXT(statp).nstimes[ns] = RES_MAXTIME; 378 EXT(statp).nssocks[ns] = -1; 379 if (!statp->nsaddr_list[ns].sin_family) 380 continue; 381 EXT(statp).ext->nsaddrs[ns].sin = 382 statp->nsaddr_list[ns]; 383 } 384 EXT(statp).nscount = statp->nscount; 385 } 386 387 /* 388 * Some resolvers want to even out the load on their nameservers. 389 * Note that RES_BLAST overrides RES_ROTATE. 390 */ 391 if ((statp->options & RES_ROTATE) != 0U && 392 (statp->options & RES_BLAST) == 0U) { 393 union res_sockaddr_union inu; 394 struct sockaddr_in ina; 395 int lastns = statp->nscount - 1; 396 int fd; 397 u_int16_t nstime; 398 399 if (EXT(statp).ext != NULL) 400 inu = EXT(statp).ext->nsaddrs[0]; 401 ina = statp->nsaddr_list[0]; 402 fd = EXT(statp).nssocks[0]; 403 nstime = EXT(statp).nstimes[0]; 404 for (ns = 0; ns < lastns; ns++) { 405 if (EXT(statp).ext != NULL) 406 EXT(statp).ext->nsaddrs[ns] = 407 EXT(statp).ext->nsaddrs[ns + 1]; 408 statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1]; 409 EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1]; 410 EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1]; 411 } 412 if (EXT(statp).ext != NULL) 413 EXT(statp).ext->nsaddrs[lastns] = inu; 414 statp->nsaddr_list[lastns] = ina; 415 EXT(statp).nssocks[lastns] = fd; 416 EXT(statp).nstimes[lastns] = nstime; 417 } 418 419 /* 420 * Send request, RETRY times, or until successful. 421 */ 422 for (try = 0; try < statp->retry; try++) { 423 for (ns = 0; ns < statp->nscount; ns++) { 424 struct sockaddr *nsap; 425 int nsaplen; 426 nsap = get_nsaddr(statp, (size_t)ns); 427 nsaplen = get_salen(nsap); 428 statp->_flags &= ~RES_F_LASTMASK; 429 statp->_flags |= (ns << RES_F_LASTSHIFT); 430 same_ns: 431 if (statp->qhook) { 432 int done = 0, loops = 0; 433 434 do { 435 res_sendhookact act; 436 437 act = (*statp->qhook)(&nsap, &buf, &buflen, 438 ans, anssiz, &resplen); 439 switch (act) { 440 case res_goahead: 441 done = 1; 442 break; 443 case res_nextns: 444 res_nclose(statp); 445 goto next_ns; 446 case res_done: 447 return (resplen); 448 case res_modified: 449 /* give the hook another try */ 450 if (++loops < 42) /*doug adams*/ 451 break; 452 /*FALLTHROUGH*/ 453 case res_error: 454 /*FALLTHROUGH*/ 455 default: 456 goto fail; 457 } 458 } while (!done); 459 } 460 461 Dprint(((statp->options & RES_DEBUG) && 462 getnameinfo(nsap, (socklen_t)nsaplen, abuf, sizeof(abuf), 463 NULL, 0, niflags) == 0), 464 (stdout, ";; Querying server (# %d) address = %s\n", 465 ns + 1, abuf)); 466 467 468 if (v_circuit) { 469 /* Use VC; at most one attempt per server. */ 470 try = statp->retry; 471 n = send_vc(statp, buf, buflen, ans, anssiz, &terrno, 472 ns); 473 if (n < 0) 474 goto fail; 475 if (n == 0) 476 goto next_ns; 477 resplen = n; 478 } else { 479 /* Use datagrams. */ 480 n = send_dg(statp, buf, buflen, ans, anssiz, &terrno, 481 ns, try, &v_circuit, &gotsomewhere); 482 if (n < 0) 483 goto fail; 484 if (n == 0) 485 goto next_ns; 486 if (v_circuit) 487 goto same_ns; 488 resplen = n; 489 } 490 491 Dprint((statp->options & RES_DEBUG) || 492 ((statp->pfcode & RES_PRF_REPLY) && 493 (statp->pfcode & RES_PRF_HEAD1)), 494 (stdout, ";; got answer:\n")); 495 496 DprintQ((statp->options & RES_DEBUG) || 497 (statp->pfcode & RES_PRF_REPLY), 498 (stdout, "%s", ""), 499 ans, (resplen > anssiz) ? anssiz : resplen); 500 501 /* 502 * If we have temporarily opened a virtual circuit, 503 * or if we haven't been asked to keep a socket open, 504 * close the socket. 505 */ 506 if ((v_circuit && (statp->options & RES_USEVC) == 0U) || 507 (statp->options & RES_STAYOPEN) == 0U) { 508 res_nclose(statp); 509 } 510 if (statp->rhook) { 511 int done = 0, loops = 0; 512 513 do { 514 res_sendhookact act; 515 516 act = (*statp->rhook)(nsap, buf, buflen, 517 ans, anssiz, &resplen); 518 switch (act) { 519 case res_goahead: 520 case res_done: 521 done = 1; 522 break; 523 case res_nextns: 524 res_nclose(statp); 525 goto next_ns; 526 case res_modified: 527 /* give the hook another try */ 528 if (++loops < 42) /*doug adams*/ 529 break; 530 /*FALLTHROUGH*/ 531 case res_error: 532 /*FALLTHROUGH*/ 533 default: 534 goto fail; 535 } 536 } while (!done); 537 538 } 539 return (resplen); 540 next_ns: ; 541 } /*foreach ns*/ 542 } /*foreach retry*/ 543 res_nclose(statp); 544 if (!v_circuit) { 545 if (!gotsomewhere) 546 errno = ECONNREFUSED; /*%< no nameservers found */ 547 else 548 errno = ETIMEDOUT; /*%< no answer obtained */ 549 } else 550 errno = terrno; 551 return (-1); 552 fail: 553 res_nclose(statp); 554 return (-1); 555 } 556 557 /* Private */ 558 559 static int 560 get_salen(sa) 561 const struct sockaddr *sa; 562 { 563 564 #ifdef HAVE_SA_LEN 565 /* There are people do not set sa_len. Be forgiving to them. */ 566 if (sa->sa_len) 567 return (sa->sa_len); 568 #endif 569 570 if (sa->sa_family == AF_INET) 571 return (sizeof(struct sockaddr_in)); 572 else if (sa->sa_family == AF_INET6) 573 return (sizeof(struct sockaddr_in6)); 574 else 575 return (0); /*%< unknown, die on connect */ 576 } 577 578 /*% 579 * pick appropriate nsaddr_list for use. see res_init() for initialization. 580 */ 581 static struct sockaddr * 582 get_nsaddr(statp, n) 583 res_state statp; 584 size_t n; 585 { 586 587 if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) { 588 /* 589 * - EXT(statp).ext->nsaddrs[n] holds an address that is larger 590 * than struct sockaddr, and 591 * - user code did not update statp->nsaddr_list[n]. 592 */ 593 return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n]; 594 } else { 595 /* 596 * - user code updated statp->nsaddr_list[n], or 597 * - statp->nsaddr_list[n] has the same content as 598 * EXT(statp).ext->nsaddrs[n]. 599 */ 600 return (struct sockaddr *)(void *)&statp->nsaddr_list[n]; 601 } 602 } 603 604 static int 605 send_vc(res_state statp, 606 const u_char *buf, int buflen, u_char *ans, int anssiz, 607 int *terrno, int ns) 608 { 609 const HEADER *hp = (const HEADER *)(const void *)buf; 610 HEADER *anhp = (HEADER *)(void *)ans; 611 struct sockaddr *nsap; 612 int nsaplen; 613 int truncating, connreset, resplen, n; 614 struct iovec iov[2]; 615 u_short len; 616 u_char *cp; 617 void *tmp; 618 619 nsap = get_nsaddr(statp, (size_t)ns); 620 nsaplen = get_salen(nsap); 621 622 connreset = 0; 623 same_ns: 624 truncating = 0; 625 626 /* Are we still talking to whom we want to talk to? */ 627 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) { 628 struct sockaddr_storage peer; 629 ISC_SOCKLEN_T size = sizeof peer; 630 631 if (getpeername(statp->_vcsock, 632 (struct sockaddr *)(void *)&peer, &size) < 0 || 633 !sock_eq((struct sockaddr *)(void *)&peer, nsap)) { 634 res_nclose(statp); 635 statp->_flags &= ~RES_F_VC; 636 } 637 } 638 639 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) { 640 if (statp->_vcsock >= 0) 641 res_nclose(statp); 642 643 statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM, 0); 644 #ifndef USE_POLL 645 if (statp->_vcsock > highestFD) { 646 res_nclose(statp); 647 errno = ENOTSOCK; 648 } 649 #endif 650 if (statp->_vcsock < 0) { 651 switch (errno) { 652 case EPROTONOSUPPORT: 653 #ifdef EPFNOSUPPORT 654 case EPFNOSUPPORT: 655 #endif 656 case EAFNOSUPPORT: 657 Perror(statp, stderr, "socket(vc)", errno); 658 return (0); 659 default: 660 *terrno = errno; 661 Perror(statp, stderr, "socket(vc)", errno); 662 return (-1); 663 } 664 } 665 errno = 0; 666 if (connect(statp->_vcsock, nsap, (socklen_t)nsaplen) < 0) { 667 *terrno = errno; 668 Aerror(statp, stderr, "connect/vc", errno, nsap, 669 nsaplen); 670 res_nclose(statp); 671 return (0); 672 } 673 statp->_flags |= RES_F_VC; 674 } 675 676 /* 677 * Send length & message 678 */ 679 ns_put16((u_short)buflen, (u_char*)(void *)&len); 680 iov[0] = evConsIovec(&len, INT16SZ); 681 DE_CONST(buf, tmp); 682 iov[1] = evConsIovec(tmp, (size_t)buflen); 683 if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) { 684 *terrno = errno; 685 Perror(statp, stderr, "write failed", errno); 686 res_nclose(statp); 687 return (0); 688 } 689 /* 690 * Receive length & response 691 */ 692 read_len: 693 cp = ans; 694 len = INT16SZ; 695 while ((n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0) { 696 cp += n; 697 if ((len -= n) == 0) 698 break; 699 } 700 if (n <= 0) { 701 *terrno = errno; 702 Perror(statp, stderr, "read failed", errno); 703 res_nclose(statp); 704 /* 705 * A long running process might get its TCP 706 * connection reset if the remote server was 707 * restarted. Requery the server instead of 708 * trying a new one. When there is only one 709 * server, this means that a query might work 710 * instead of failing. We only allow one reset 711 * per query to prevent looping. 712 */ 713 if (*terrno == ECONNRESET && !connreset) { 714 connreset = 1; 715 res_nclose(statp); 716 goto same_ns; 717 } 718 res_nclose(statp); 719 return (0); 720 } 721 resplen = ns_get16(ans); 722 if (resplen > anssiz) { 723 Dprint(statp->options & RES_DEBUG, 724 (stdout, ";; response truncated\n") 725 ); 726 truncating = 1; 727 len = anssiz; 728 } else 729 len = resplen; 730 if (len < HFIXEDSZ) { 731 /* 732 * Undersized message. 733 */ 734 Dprint(statp->options & RES_DEBUG, 735 (stdout, ";; undersized: %d\n", len)); 736 *terrno = EMSGSIZE; 737 res_nclose(statp); 738 return (0); 739 } 740 cp = ans; 741 while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0){ 742 cp += n; 743 len -= n; 744 } 745 if (n <= 0) { 746 *terrno = errno; 747 Perror(statp, stderr, "read(vc)", errno); 748 res_nclose(statp); 749 return (0); 750 } 751 if (truncating) { 752 /* 753 * Flush rest of answer so connection stays in synch. 754 */ 755 anhp->tc = 1; 756 len = resplen - anssiz; 757 while (len != 0) { 758 char junk[PACKETSZ]; 759 760 n = read(statp->_vcsock, junk, 761 (len > sizeof junk) ? sizeof junk : len); 762 if (n > 0) 763 len -= n; 764 else 765 break; 766 } 767 } 768 /* 769 * If the calling applicating has bailed out of 770 * a previous call and failed to arrange to have 771 * the circuit closed or the server has got 772 * itself confused, then drop the packet and 773 * wait for the correct one. 774 */ 775 if (hp->id != anhp->id) { 776 DprintQ((statp->options & RES_DEBUG) || 777 (statp->pfcode & RES_PRF_REPLY), 778 (stdout, ";; old answer (unexpected):\n"), 779 ans, (resplen > anssiz) ? anssiz: resplen); 780 goto read_len; 781 } 782 783 /* 784 * All is well, or the error is fatal. Signal that the 785 * next nameserver ought not be tried. 786 */ 787 return (resplen); 788 } 789 790 static int 791 send_dg(res_state statp, const u_char *buf, int buflen, u_char *ans, 792 int anssiz, int *terrno, int ns, int try, int *v_circuit, 793 int *gotsomewhere) 794 { 795 const HEADER *hp = (const HEADER *)(const void *)buf; 796 HEADER *anhp = (HEADER *)(void *)ans; 797 const struct sockaddr *nsap; 798 int nsaplen; 799 struct timespec now, timeout, finish; 800 struct sockaddr_storage from; 801 ISC_SOCKLEN_T fromlen; 802 int resplen, seconds, n, s; 803 #ifdef USE_POLL 804 int polltimeout; 805 struct pollfd pollfd; 806 #else 807 fd_set dsmask; 808 #endif 809 810 nsap = get_nsaddr(statp, (size_t)ns); 811 nsaplen = get_salen(nsap); 812 if (EXT(statp).nssocks[ns] == -1) { 813 EXT(statp).nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM, 0); 814 #ifndef USE_POLL 815 if (EXT(statp).nssocks[ns] > highestFD) { 816 res_nclose(statp); 817 errno = ENOTSOCK; 818 } 819 #endif 820 if (EXT(statp).nssocks[ns] < 0) { 821 switch (errno) { 822 case EPROTONOSUPPORT: 823 #ifdef EPFNOSUPPORT 824 case EPFNOSUPPORT: 825 #endif 826 case EAFNOSUPPORT: 827 Perror(statp, stderr, "socket(dg)", errno); 828 return (0); 829 default: 830 *terrno = errno; 831 Perror(statp, stderr, "socket(dg)", errno); 832 return (-1); 833 } 834 } 835 #ifndef CANNOT_CONNECT_DGRAM 836 /* 837 * On a 4.3BSD+ machine (client and server, 838 * actually), sending to a nameserver datagram 839 * port with no nameserver will cause an 840 * ICMP port unreachable message to be returned. 841 * If our datagram socket is "connected" to the 842 * server, we get an ECONNREFUSED error on the next 843 * socket operation, and select returns if the 844 * error message is received. We can thus detect 845 * the absence of a nameserver without timing out. 846 */ 847 if (connect(EXT(statp).nssocks[ns], nsap, (socklen_t)nsaplen) < 0) { 848 Aerror(statp, stderr, "connect(dg)", errno, nsap, 849 nsaplen); 850 res_nclose(statp); 851 return (0); 852 } 853 #endif /* !CANNOT_CONNECT_DGRAM */ 854 Dprint(statp->options & RES_DEBUG, 855 (stdout, ";; new DG socket\n")) 856 } 857 s = EXT(statp).nssocks[ns]; 858 #ifndef CANNOT_CONNECT_DGRAM 859 if (send(s, (const char*)buf, (size_t)buflen, 0) != buflen) { 860 Perror(statp, stderr, "send", errno); 861 res_nclose(statp); 862 return (0); 863 } 864 #else /* !CANNOT_CONNECT_DGRAM */ 865 if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) 866 { 867 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); 868 res_nclose(statp); 869 return (0); 870 } 871 #endif /* !CANNOT_CONNECT_DGRAM */ 872 873 /* 874 * Wait for reply. 875 */ 876 seconds = (statp->retrans << try); 877 if (ns > 0) 878 seconds /= statp->nscount; 879 if (seconds <= 0) 880 seconds = 1; 881 now = evNowTime(); 882 timeout = evConsTime((long)seconds, 0L); 883 finish = evAddTime(now, timeout); 884 goto nonow; 885 wait: 886 now = evNowTime(); 887 nonow: 888 #ifndef USE_POLL 889 FD_ZERO(&dsmask); 890 FD_SET(s, &dsmask); 891 if (evCmpTime(finish, now) > 0) 892 timeout = evSubTime(finish, now); 893 else 894 timeout = evConsTime(0L, 0L); 895 n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL); 896 #else 897 timeout = evSubTime(finish, now); 898 if (timeout.tv_sec < 0) 899 timeout = evConsTime(0L, 0L); 900 polltimeout = 1000*timeout.tv_sec + 901 timeout.tv_nsec/1000000; 902 pollfd.fd = s; 903 pollfd.events = POLLRDNORM; 904 n = poll(&pollfd, 1, polltimeout); 905 #endif /* USE_POLL */ 906 907 if (n == 0) { 908 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); 909 *gotsomewhere = 1; 910 return (0); 911 } 912 if (n < 0) { 913 if (errno == EINTR) 914 goto wait; 915 #ifndef USE_POLL 916 Perror(statp, stderr, "select", errno); 917 #else 918 Perror(statp, stderr, "poll", errno); 919 #endif /* USE_POLL */ 920 res_nclose(statp); 921 return (0); 922 } 923 errno = 0; 924 fromlen = sizeof(from); 925 resplen = recvfrom(s, (char*)ans, (size_t)anssiz,0, 926 (struct sockaddr *)(void *)&from, &fromlen); 927 if (resplen <= 0) { 928 Perror(statp, stderr, "recvfrom", errno); 929 res_nclose(statp); 930 return (0); 931 } 932 *gotsomewhere = 1; 933 if (resplen < HFIXEDSZ) { 934 /* 935 * Undersized message. 936 */ 937 Dprint(statp->options & RES_DEBUG, 938 (stdout, ";; undersized: %d\n", 939 resplen)); 940 *terrno = EMSGSIZE; 941 res_nclose(statp); 942 return (0); 943 } 944 if (hp->id != anhp->id) { 945 /* 946 * response from old query, ignore it. 947 * XXX - potential security hazard could 948 * be detected here. 949 */ 950 DprintQ((statp->options & RES_DEBUG) || 951 (statp->pfcode & RES_PRF_REPLY), 952 (stdout, ";; old answer:\n"), 953 ans, (resplen > anssiz) ? anssiz : resplen); 954 goto wait; 955 } 956 if (!(statp->options & RES_INSECURE1) && 957 !res_ourserver_p(statp, (struct sockaddr *)(void *)&from)) { 958 /* 959 * response from wrong server? ignore it. 960 * XXX - potential security hazard could 961 * be detected here. 962 */ 963 DprintQ((statp->options & RES_DEBUG) || 964 (statp->pfcode & RES_PRF_REPLY), 965 (stdout, ";; not our server:\n"), 966 ans, (resplen > anssiz) ? anssiz : resplen); 967 goto wait; 968 } 969 #ifdef RES_USE_EDNS0 970 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) { 971 /* 972 * Do not retry if the server do not understand EDNS0. 973 * The case has to be captured here, as FORMERR packet do not 974 * carry query section, hence res_queriesmatch() returns 0. 975 */ 976 DprintQ(statp->options & RES_DEBUG, 977 (stdout, "server rejected query with EDNS0:\n"), 978 ans, (resplen > anssiz) ? anssiz : resplen); 979 /* record the error */ 980 statp->_flags |= RES_F_EDNS0ERR; 981 res_nclose(statp); 982 return (0); 983 } 984 #endif 985 if (!(statp->options & RES_INSECURE2) && 986 !res_queriesmatch(buf, buf + buflen, 987 ans, ans + anssiz)) { 988 /* 989 * response contains wrong query? ignore it. 990 * XXX - potential security hazard could 991 * be detected here. 992 */ 993 DprintQ((statp->options & RES_DEBUG) || 994 (statp->pfcode & RES_PRF_REPLY), 995 (stdout, ";; wrong query name:\n"), 996 ans, (resplen > anssiz) ? anssiz : resplen); 997 goto wait; 998 } 999 if (anhp->rcode == SERVFAIL || 1000 anhp->rcode == NOTIMP || 1001 anhp->rcode == REFUSED) { 1002 DprintQ(statp->options & RES_DEBUG, 1003 (stdout, "server rejected query:\n"), 1004 ans, (resplen > anssiz) ? anssiz : resplen); 1005 res_nclose(statp); 1006 /* don't retry if called from dig */ 1007 if (!statp->pfcode) 1008 return (0); 1009 } 1010 if (!(statp->options & RES_IGNTC) && anhp->tc) { 1011 /* 1012 * To get the rest of answer, 1013 * use TCP with same server. 1014 */ 1015 Dprint(statp->options & RES_DEBUG, 1016 (stdout, ";; truncated answer\n")); 1017 *v_circuit = 1; 1018 res_nclose(statp); 1019 return (1); 1020 } 1021 /* 1022 * All is well, or the error is fatal. Signal that the 1023 * next nameserver ought not be tried. 1024 */ 1025 return (resplen); 1026 } 1027 1028 static void 1029 Aerror(const res_state statp, FILE *file, const char *string, int error, 1030 const struct sockaddr *address, int alen) 1031 { 1032 int save = errno; 1033 char hbuf[NI_MAXHOST]; 1034 char sbuf[NI_MAXSERV]; 1035 1036 alen = alen; 1037 1038 if ((statp->options & RES_DEBUG) != 0U) { 1039 if (getnameinfo(address, (socklen_t)alen, hbuf, sizeof(hbuf), 1040 sbuf, sizeof(sbuf), niflags)) { 1041 strncpy(hbuf, "?", sizeof(hbuf) - 1); 1042 hbuf[sizeof(hbuf) - 1] = '\0'; 1043 strncpy(sbuf, "?", sizeof(sbuf) - 1); 1044 sbuf[sizeof(sbuf) - 1] = '\0'; 1045 } 1046 fprintf(file, "res_send: %s ([%s].%s): %s\n", 1047 string, hbuf, sbuf, strerror(error)); 1048 } 1049 errno = save; 1050 } 1051 1052 static void 1053 Perror(const res_state statp, FILE *file, const char *string, int error) { 1054 int save = errno; 1055 1056 if ((statp->options & RES_DEBUG) != 0U) 1057 fprintf(file, "res_send: %s: %s\n", 1058 string, strerror(error)); 1059 errno = save; 1060 } 1061 1062 static int 1063 sock_eq(struct sockaddr *a, struct sockaddr *b) { 1064 struct sockaddr_in *a4, *b4; 1065 struct sockaddr_in6 *a6, *b6; 1066 1067 if (a->sa_family != b->sa_family) 1068 return 0; 1069 switch (a->sa_family) { 1070 case AF_INET: 1071 a4 = (struct sockaddr_in *)(void *)a; 1072 b4 = (struct sockaddr_in *)(void *)b; 1073 return a4->sin_port == b4->sin_port && 1074 a4->sin_addr.s_addr == b4->sin_addr.s_addr; 1075 case AF_INET6: 1076 a6 = (struct sockaddr_in6 *)(void *)a; 1077 b6 = (struct sockaddr_in6 *)(void *)b; 1078 return a6->sin6_port == b6->sin6_port && 1079 #ifdef HAVE_SIN6_SCOPE_ID 1080 a6->sin6_scope_id == b6->sin6_scope_id && 1081 #endif 1082 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr); 1083 default: 1084 return 0; 1085 } 1086 } 1087 1088 #if defined(NEED_PSELECT) && !defined(USE_POLL) 1089 /* XXX needs to move to the porting library. */ 1090 static int 1091 pselect(int nfds, void *rfds, void *wfds, void *efds, 1092 struct timespec *tsp, const sigset_t *sigmask) 1093 { 1094 struct timeval tv, *tvp; 1095 sigset_t sigs; 1096 int n; 1097 1098 if (tsp) { 1099 tvp = &tv; 1100 tv = evTimeVal(*tsp); 1101 } else 1102 tvp = NULL; 1103 if (sigmask) 1104 sigprocmask(SIG_SETMASK, sigmask, &sigs); 1105 n = select(nfds, rfds, wfds, efds, tvp); 1106 if (sigmask) 1107 sigprocmask(SIG_SETMASK, &sigs, NULL); 1108 if (tsp) 1109 *tsp = evTimeSpec(tv); 1110 return (n); 1111 } 1112 #endif 1113