res_send.c revision 156952
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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34/* 35 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 36 * 37 * Permission to use, copy, modify, and distribute this software for any 38 * purpose with or without fee is hereby granted, provided that the above 39 * copyright notice and this permission notice appear in all copies, and that 40 * the name of Digital Equipment Corporation not be used in advertising or 41 * publicity pertaining to distribution of the document or software without 42 * specific, written prior permission. 43 * 44 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 45 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 46 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 47 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 48 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 49 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 50 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 51 * SOFTWARE. 52 */ 53 54/* 55 * Copyright (c) 2005 by Internet Systems Consortium, Inc. ("ISC") 56 * Portions Copyright (c) 1996-1999 by Internet Software Consortium. 57 * 58 * Permission to use, copy, modify, and distribute this software for any 59 * purpose with or without fee is hereby granted, provided that the above 60 * copyright notice and this permission notice appear in all copies. 61 * 62 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 63 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 64 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 65 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 66 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 67 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 68 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 69 */ 70 71#if defined(LIBC_SCCS) && !defined(lint) 72static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93"; 73static const char rcsid[] = "$Id: res_send.c,v 1.5.2.2.4.7 2005/08/15 02:04:41 marka Exp $"; 74#endif /* LIBC_SCCS and not lint */ 75 76/* 77 * Send query to name server and wait for reply. 78 */ 79 80#include "port_before.h" 81#include "fd_setsize.h" 82 83#include <sys/types.h> 84#include <sys/param.h> 85#include <sys/time.h> 86#include <sys/socket.h> 87#include <sys/uio.h> 88 89#include <netinet/in.h> 90#include <arpa/nameser.h> 91#include <arpa/inet.h> 92 93#include <errno.h> 94#include <netdb.h> 95#include <resolv.h> 96#include <signal.h> 97#include <stdio.h> 98#include <stdlib.h> 99#include <string.h> 100#include <unistd.h> 101 102#include <isc/eventlib.h> 103 104#include "port_after.h" 105 106#ifdef USE_POLL 107#ifdef HAVE_STROPTS_H 108#include <stropts.h> 109#endif 110#include <poll.h> 111#endif /* USE_POLL */ 112 113/* Options. Leave them on. */ 114#define DEBUG 115#include "res_debug.h" 116#include "res_private.h" 117 118#define EXT(res) ((res)->_u._ext) 119 120#ifndef USE_POLL 121static const int highestFD = FD_SETSIZE - 1; 122#else 123static int highestFD = 0; 124#endif 125 126/* Forward. */ 127 128static int get_salen __P((const struct sockaddr *)); 129static struct sockaddr * get_nsaddr __P((res_state, size_t)); 130static int send_vc(res_state, const u_char *, int, 131 u_char *, int, int *, int); 132static int send_dg(res_state, const u_char *, int, 133 u_char *, int, int *, int, 134 int *, int *); 135static void Aerror(const res_state, FILE *, const char *, int, 136 const struct sockaddr *, int); 137static void Perror(const res_state, FILE *, const char *, int); 138static int sock_eq(struct sockaddr *, struct sockaddr *); 139#if defined(NEED_PSELECT) && !defined(USE_POLL) 140static int pselect(int, void *, void *, void *, 141 struct timespec *, 142 const sigset_t *); 143#endif 144void res_pquery(const res_state, const u_char *, int, FILE *); 145 146static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV; 147 148/* Public. */ 149 150/* int 151 * res_isourserver(ina) 152 * looks up "ina" in _res.ns_addr_list[] 153 * returns: 154 * 0 : not found 155 * >0 : found 156 * author: 157 * paul vixie, 29may94 158 */ 159int 160res_ourserver_p(const res_state statp, const struct sockaddr *sa) { 161 const struct sockaddr_in *inp, *srv; 162 const struct sockaddr_in6 *in6p, *srv6; 163 int ns; 164 165 switch (sa->sa_family) { 166 case AF_INET: 167 inp = (const struct sockaddr_in *)sa; 168 for (ns = 0; ns < statp->nscount; ns++) { 169 srv = (struct sockaddr_in *)get_nsaddr(statp, ns); 170 if (srv->sin_family == inp->sin_family && 171 srv->sin_port == inp->sin_port && 172 (srv->sin_addr.s_addr == INADDR_ANY || 173 srv->sin_addr.s_addr == inp->sin_addr.s_addr)) 174 return (1); 175 } 176 break; 177 case AF_INET6: 178 if (EXT(statp).ext == NULL) 179 break; 180 in6p = (const struct sockaddr_in6 *)sa; 181 for (ns = 0; ns < statp->nscount; ns++) { 182 srv6 = (struct sockaddr_in6 *)get_nsaddr(statp, ns); 183 if (srv6->sin6_family == in6p->sin6_family && 184 srv6->sin6_port == in6p->sin6_port && 185#ifdef HAVE_SIN6_SCOPE_ID 186 (srv6->sin6_scope_id == 0 || 187 srv6->sin6_scope_id == in6p->sin6_scope_id) && 188#endif 189 (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) || 190 IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr))) 191 return (1); 192 } 193 break; 194 default: 195 break; 196 } 197 return (0); 198} 199 200/* int 201 * res_nameinquery(name, type, class, buf, eom) 202 * look for (name,type,class) in the query section of packet (buf,eom) 203 * requires: 204 * buf + HFIXEDSZ <= eom 205 * returns: 206 * -1 : format error 207 * 0 : not found 208 * >0 : found 209 * author: 210 * paul vixie, 29may94 211 */ 212int 213res_nameinquery(const char *name, int type, int class, 214 const u_char *buf, const u_char *eom) 215{ 216 const u_char *cp = buf + HFIXEDSZ; 217 int qdcount = ntohs(((const HEADER*)buf)->qdcount); 218 219 while (qdcount-- > 0) { 220 char tname[MAXDNAME+1]; 221 int n, ttype, tclass; 222 223 n = dn_expand(buf, eom, cp, tname, sizeof tname); 224 if (n < 0) 225 return (-1); 226 cp += n; 227 if (cp + 2 * INT16SZ > eom) 228 return (-1); 229 ttype = ns_get16(cp); cp += INT16SZ; 230 tclass = ns_get16(cp); cp += INT16SZ; 231 if (ttype == type && tclass == class && 232 ns_samename(tname, name) == 1) 233 return (1); 234 } 235 return (0); 236} 237 238/* int 239 * res_queriesmatch(buf1, eom1, buf2, eom2) 240 * is there a 1:1 mapping of (name,type,class) 241 * in (buf1,eom1) and (buf2,eom2)? 242 * returns: 243 * -1 : format error 244 * 0 : not a 1:1 mapping 245 * >0 : is a 1:1 mapping 246 * author: 247 * paul vixie, 29may94 248 */ 249int 250res_queriesmatch(const u_char *buf1, const u_char *eom1, 251 const u_char *buf2, const u_char *eom2) 252{ 253 const u_char *cp = buf1 + HFIXEDSZ; 254 int qdcount = ntohs(((const HEADER*)buf1)->qdcount); 255 256 if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2) 257 return (-1); 258 259 /* 260 * Only header section present in replies to 261 * dynamic update packets. 262 */ 263 if ((((const HEADER *)buf1)->opcode == ns_o_update) && 264 (((const HEADER *)buf2)->opcode == ns_o_update)) 265 return (1); 266 267 if (qdcount != ntohs(((const HEADER*)buf2)->qdcount)) 268 return (0); 269 while (qdcount-- > 0) { 270 char tname[MAXDNAME+1]; 271 int n, ttype, tclass; 272 273 n = dn_expand(buf1, eom1, cp, tname, sizeof tname); 274 if (n < 0) 275 return (-1); 276 cp += n; 277 if (cp + 2 * INT16SZ > eom1) 278 return (-1); 279 ttype = ns_get16(cp); cp += INT16SZ; 280 tclass = ns_get16(cp); cp += INT16SZ; 281 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) 282 return (0); 283 } 284 return (1); 285} 286 287int 288res_nsend(res_state statp, 289 const u_char *buf, int buflen, u_char *ans, int anssiz) 290{ 291 int gotsomewhere, terrno, try, v_circuit, resplen, ns, n; 292 char abuf[NI_MAXHOST]; 293 294#ifdef USE_POLL 295 highestFD = sysconf(_SC_OPEN_MAX) - 1; 296#endif 297 298 if (statp->nscount == 0) { 299 errno = ESRCH; 300 return (-1); 301 } 302 if (anssiz < HFIXEDSZ) { 303 errno = EINVAL; 304 return (-1); 305 } 306 DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY), 307 (stdout, ";; res_send()\n"), buf, buflen); 308 v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ; 309 gotsomewhere = 0; 310 terrno = ETIMEDOUT; 311 312 /* 313 * If the ns_addr_list in the resolver context has changed, then 314 * invalidate our cached copy and the associated timing data. 315 */ 316 if (EXT(statp).nscount != 0) { 317 int needclose = 0; 318 struct sockaddr_storage peer; 319 ISC_SOCKLEN_T peerlen; 320 321 if (EXT(statp).nscount != statp->nscount) 322 needclose++; 323 else 324 for (ns = 0; ns < statp->nscount; ns++) { 325 if (statp->nsaddr_list[ns].sin_family && 326 !sock_eq((struct sockaddr *)&statp->nsaddr_list[ns], 327 (struct sockaddr *)&EXT(statp).ext->nsaddrs[ns])) { 328 needclose++; 329 break; 330 } 331 332 if (EXT(statp).nssocks[ns] == -1) 333 continue; 334 peerlen = sizeof(peer); 335 if (getsockname(EXT(statp).nssocks[ns], 336 (struct sockaddr *)&peer, &peerlen) < 0) { 337 needclose++; 338 break; 339 } 340 if (!sock_eq((struct sockaddr *)&peer, 341 get_nsaddr(statp, ns))) { 342 needclose++; 343 break; 344 } 345 } 346 if (needclose) { 347 res_nclose(statp); 348 EXT(statp).nscount = 0; 349 } 350 } 351 352 /* 353 * Maybe initialize our private copy of the ns_addr_list. 354 */ 355 if (EXT(statp).nscount == 0) { 356 for (ns = 0; ns < statp->nscount; ns++) { 357 EXT(statp).nstimes[ns] = RES_MAXTIME; 358 EXT(statp).nssocks[ns] = -1; 359 if (!statp->nsaddr_list[ns].sin_family) 360 continue; 361 EXT(statp).ext->nsaddrs[ns].sin = 362 statp->nsaddr_list[ns]; 363 } 364 EXT(statp).nscount = statp->nscount; 365 } 366 367 /* 368 * Some resolvers want to even out the load on their nameservers. 369 * Note that RES_BLAST overrides RES_ROTATE. 370 */ 371 if ((statp->options & RES_ROTATE) != 0U && 372 (statp->options & RES_BLAST) == 0U) { 373 union res_sockaddr_union inu; 374 struct sockaddr_in ina; 375 int lastns = statp->nscount - 1; 376 int fd; 377 u_int16_t nstime; 378 379 if (EXT(statp).ext != NULL) 380 inu = EXT(statp).ext->nsaddrs[0]; 381 ina = statp->nsaddr_list[0]; 382 fd = EXT(statp).nssocks[0]; 383 nstime = EXT(statp).nstimes[0]; 384 for (ns = 0; ns < lastns; ns++) { 385 if (EXT(statp).ext != NULL) 386 EXT(statp).ext->nsaddrs[ns] = 387 EXT(statp).ext->nsaddrs[ns + 1]; 388 statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1]; 389 EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1]; 390 EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1]; 391 } 392 if (EXT(statp).ext != NULL) 393 EXT(statp).ext->nsaddrs[lastns] = inu; 394 statp->nsaddr_list[lastns] = ina; 395 EXT(statp).nssocks[lastns] = fd; 396 EXT(statp).nstimes[lastns] = nstime; 397 } 398 399 /* 400 * Send request, RETRY times, or until successful. 401 */ 402 for (try = 0; try < statp->retry; try++) { 403 for (ns = 0; ns < statp->nscount; ns++) { 404 struct sockaddr *nsap; 405 int nsaplen; 406 nsap = get_nsaddr(statp, ns); 407 nsaplen = get_salen(nsap); 408 statp->_flags &= ~RES_F_LASTMASK; 409 statp->_flags |= (ns << RES_F_LASTSHIFT); 410 same_ns: 411 if (statp->qhook) { 412 int done = 0, loops = 0; 413 414 do { 415 res_sendhookact act; 416 417 act = (*statp->qhook)(&nsap, &buf, &buflen, 418 ans, anssiz, &resplen); 419 switch (act) { 420 case res_goahead: 421 done = 1; 422 break; 423 case res_nextns: 424 res_nclose(statp); 425 goto next_ns; 426 case res_done: 427 return (resplen); 428 case res_modified: 429 /* give the hook another try */ 430 if (++loops < 42) /*doug adams*/ 431 break; 432 /*FALLTHROUGH*/ 433 case res_error: 434 /*FALLTHROUGH*/ 435 default: 436 goto fail; 437 } 438 } while (!done); 439 } 440 441 Dprint(((statp->options & RES_DEBUG) && 442 getnameinfo(nsap, nsaplen, abuf, sizeof(abuf), 443 NULL, 0, niflags) == 0), 444 (stdout, ";; Querying server (# %d) address = %s\n", 445 ns + 1, abuf)); 446 447 448 if (v_circuit) { 449 /* Use VC; at most one attempt per server. */ 450 try = statp->retry; 451 n = send_vc(statp, buf, buflen, ans, anssiz, &terrno, 452 ns); 453 if (n < 0) 454 goto fail; 455 if (n == 0) 456 goto next_ns; 457 resplen = n; 458 } else { 459 /* Use datagrams. */ 460 n = send_dg(statp, buf, buflen, ans, anssiz, &terrno, 461 ns, &v_circuit, &gotsomewhere); 462 if (n < 0) 463 goto fail; 464 if (n == 0) 465 goto next_ns; 466 if (v_circuit) 467 goto same_ns; 468 resplen = n; 469 } 470 471 Dprint((statp->options & RES_DEBUG) || 472 ((statp->pfcode & RES_PRF_REPLY) && 473 (statp->pfcode & RES_PRF_HEAD1)), 474 (stdout, ";; got answer:\n")); 475 476 DprintQ((statp->options & RES_DEBUG) || 477 (statp->pfcode & RES_PRF_REPLY), 478 (stdout, "%s", ""), 479 ans, (resplen > anssiz) ? anssiz : resplen); 480 481 /* 482 * If we have temporarily opened a virtual circuit, 483 * or if we haven't been asked to keep a socket open, 484 * close the socket. 485 */ 486 if ((v_circuit && (statp->options & RES_USEVC) == 0U) || 487 (statp->options & RES_STAYOPEN) == 0U) { 488 res_nclose(statp); 489 } 490 if (statp->rhook) { 491 int done = 0, loops = 0; 492 493 do { 494 res_sendhookact act; 495 496 act = (*statp->rhook)(nsap, buf, buflen, 497 ans, anssiz, &resplen); 498 switch (act) { 499 case res_goahead: 500 case res_done: 501 done = 1; 502 break; 503 case res_nextns: 504 res_nclose(statp); 505 goto next_ns; 506 case res_modified: 507 /* give the hook another try */ 508 if (++loops < 42) /*doug adams*/ 509 break; 510 /*FALLTHROUGH*/ 511 case res_error: 512 /*FALLTHROUGH*/ 513 default: 514 goto fail; 515 } 516 } while (!done); 517 518 } 519 return (resplen); 520 next_ns: ; 521 } /*foreach ns*/ 522 } /*foreach retry*/ 523 res_nclose(statp); 524 if (!v_circuit) { 525 if (!gotsomewhere) 526 errno = ECONNREFUSED; /* no nameservers found */ 527 else 528 errno = ETIMEDOUT; /* no answer obtained */ 529 } else 530 errno = terrno; 531 return (-1); 532 fail: 533 res_nclose(statp); 534 return (-1); 535} 536 537/* Private */ 538 539static int 540get_salen(sa) 541 const struct sockaddr *sa; 542{ 543 544#ifdef HAVE_SA_LEN 545 /* There are people do not set sa_len. Be forgiving to them. */ 546 if (sa->sa_len) 547 return (sa->sa_len); 548#endif 549 550 if (sa->sa_family == AF_INET) 551 return (sizeof(struct sockaddr_in)); 552 else if (sa->sa_family == AF_INET6) 553 return (sizeof(struct sockaddr_in6)); 554 else 555 return (0); /* unknown, die on connect */ 556} 557 558/* 559 * pick appropriate nsaddr_list for use. see res_init() for initialization. 560 */ 561static struct sockaddr * 562get_nsaddr(statp, n) 563 res_state statp; 564 size_t n; 565{ 566 567 if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) { 568 /* 569 * - EXT(statp).ext->nsaddrs[n] holds an address that is larger 570 * than struct sockaddr, and 571 * - user code did not update statp->nsaddr_list[n]. 572 */ 573 return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n]; 574 } else { 575 /* 576 * - user code updated statp->nsaddr_list[n], or 577 * - statp->nsaddr_list[n] has the same content as 578 * EXT(statp).ext->nsaddrs[n]. 579 */ 580 return (struct sockaddr *)(void *)&statp->nsaddr_list[n]; 581 } 582} 583 584static int 585send_vc(res_state statp, 586 const u_char *buf, int buflen, u_char *ans, int anssiz, 587 int *terrno, int ns) 588{ 589 const HEADER *hp = (const HEADER *) buf; 590 HEADER *anhp = (HEADER *) ans; 591 struct sockaddr *nsap; 592 int nsaplen; 593 int truncating, connreset, resplen, n; 594 struct iovec iov[2]; 595 u_short len; 596 u_char *cp; 597 void *tmp; 598 599 nsap = get_nsaddr(statp, ns); 600 nsaplen = get_salen(nsap); 601 602 connreset = 0; 603 same_ns: 604 truncating = 0; 605 606 /* Are we still talking to whom we want to talk to? */ 607 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) { 608 struct sockaddr_storage peer; 609 ISC_SOCKLEN_T size = sizeof peer; 610 611 if (getpeername(statp->_vcsock, 612 (struct sockaddr *)&peer, &size) < 0 || 613 !sock_eq((struct sockaddr *)&peer, nsap)) { 614 res_nclose(statp); 615 statp->_flags &= ~RES_F_VC; 616 } 617 } 618 619 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) { 620 if (statp->_vcsock >= 0) 621 res_nclose(statp); 622 623 statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM, 0); 624 if (statp->_vcsock > highestFD) { 625 res_nclose(statp); 626 errno = ENOTSOCK; 627 } 628 if (statp->_vcsock < 0) { 629 switch (errno) { 630 case EPROTONOSUPPORT: 631#ifdef EPFNOSUPPORT 632 case EPFNOSUPPORT: 633#endif 634 case EAFNOSUPPORT: 635 Perror(statp, stderr, "socket(vc)", errno); 636 return (0); 637 default: 638 *terrno = errno; 639 Perror(statp, stderr, "socket(vc)", errno); 640 return (-1); 641 } 642 } 643 errno = 0; 644 if (connect(statp->_vcsock, nsap, nsaplen) < 0) { 645 *terrno = errno; 646 Aerror(statp, stderr, "connect/vc", errno, nsap, 647 nsaplen); 648 res_nclose(statp); 649 return (0); 650 } 651 statp->_flags |= RES_F_VC; 652 } 653 654 /* 655 * Send length & message 656 */ 657 ns_put16((u_short)buflen, (u_char*)&len); 658 iov[0] = evConsIovec(&len, INT16SZ); 659 DE_CONST(buf, tmp); 660 iov[1] = evConsIovec(tmp, buflen); 661 if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) { 662 *terrno = errno; 663 Perror(statp, stderr, "write failed", errno); 664 res_nclose(statp); 665 return (0); 666 } 667 /* 668 * Receive length & response 669 */ 670 read_len: 671 cp = ans; 672 len = INT16SZ; 673 while ((n = read(statp->_vcsock, (char *)cp, (int)len)) > 0) { 674 cp += n; 675 if ((len -= n) == 0) 676 break; 677 } 678 if (n <= 0) { 679 *terrno = errno; 680 Perror(statp, stderr, "read failed", errno); 681 res_nclose(statp); 682 /* 683 * A long running process might get its TCP 684 * connection reset if the remote server was 685 * restarted. Requery the server instead of 686 * trying a new one. When there is only one 687 * server, this means that a query might work 688 * instead of failing. We only allow one reset 689 * per query to prevent looping. 690 */ 691 if (*terrno == ECONNRESET && !connreset) { 692 connreset = 1; 693 res_nclose(statp); 694 goto same_ns; 695 } 696 res_nclose(statp); 697 return (0); 698 } 699 resplen = ns_get16(ans); 700 if (resplen > anssiz) { 701 Dprint(statp->options & RES_DEBUG, 702 (stdout, ";; response truncated\n") 703 ); 704 truncating = 1; 705 len = anssiz; 706 } else 707 len = resplen; 708 if (len < HFIXEDSZ) { 709 /* 710 * Undersized message. 711 */ 712 Dprint(statp->options & RES_DEBUG, 713 (stdout, ";; undersized: %d\n", len)); 714 *terrno = EMSGSIZE; 715 res_nclose(statp); 716 return (0); 717 } 718 cp = ans; 719 while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (int)len)) > 0){ 720 cp += n; 721 len -= n; 722 } 723 if (n <= 0) { 724 *terrno = errno; 725 Perror(statp, stderr, "read(vc)", errno); 726 res_nclose(statp); 727 return (0); 728 } 729 if (truncating) { 730 /* 731 * Flush rest of answer so connection stays in synch. 732 */ 733 anhp->tc = 1; 734 len = resplen - anssiz; 735 while (len != 0) { 736 char junk[PACKETSZ]; 737 738 n = read(statp->_vcsock, junk, 739 (len > sizeof junk) ? sizeof junk : len); 740 if (n > 0) 741 len -= n; 742 else 743 break; 744 } 745 } 746 /* 747 * If the calling applicating has bailed out of 748 * a previous call and failed to arrange to have 749 * the circuit closed or the server has got 750 * itself confused, then drop the packet and 751 * wait for the correct one. 752 */ 753 if (hp->id != anhp->id) { 754 DprintQ((statp->options & RES_DEBUG) || 755 (statp->pfcode & RES_PRF_REPLY), 756 (stdout, ";; old answer (unexpected):\n"), 757 ans, (resplen > anssiz) ? anssiz: resplen); 758 goto read_len; 759 } 760 761 /* 762 * All is well, or the error is fatal. Signal that the 763 * next nameserver ought not be tried. 764 */ 765 return (resplen); 766} 767 768static int 769send_dg(res_state statp, 770 const u_char *buf, int buflen, u_char *ans, int anssiz, 771 int *terrno, int ns, int *v_circuit, int *gotsomewhere) 772{ 773 const HEADER *hp = (const HEADER *) buf; 774 HEADER *anhp = (HEADER *) ans; 775 const struct sockaddr *nsap; 776 int nsaplen; 777 struct timespec now, timeout, finish; 778 struct sockaddr_storage from; 779 ISC_SOCKLEN_T fromlen; 780 int resplen, seconds, n, s; 781#ifdef USE_POLL 782 int polltimeout; 783 struct pollfd pollfd; 784#else 785 fd_set dsmask; 786#endif 787 788 nsap = get_nsaddr(statp, ns); 789 nsaplen = get_salen(nsap); 790 if (EXT(statp).nssocks[ns] == -1) { 791 EXT(statp).nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM, 0); 792 if (EXT(statp).nssocks[ns] > highestFD) { 793 res_nclose(statp); 794 errno = ENOTSOCK; 795 } 796 if (EXT(statp).nssocks[ns] < 0) { 797 switch (errno) { 798 case EPROTONOSUPPORT: 799#ifdef EPFNOSUPPORT 800 case EPFNOSUPPORT: 801#endif 802 case EAFNOSUPPORT: 803 Perror(statp, stderr, "socket(dg)", errno); 804 return (0); 805 default: 806 *terrno = errno; 807 Perror(statp, stderr, "socket(dg)", errno); 808 return (-1); 809 } 810 } 811#ifndef CANNOT_CONNECT_DGRAM 812 /* 813 * On a 4.3BSD+ machine (client and server, 814 * actually), sending to a nameserver datagram 815 * port with no nameserver will cause an 816 * ICMP port unreachable message to be returned. 817 * If our datagram socket is "connected" to the 818 * server, we get an ECONNREFUSED error on the next 819 * socket operation, and select returns if the 820 * error message is received. We can thus detect 821 * the absence of a nameserver without timing out. 822 */ 823 if (connect(EXT(statp).nssocks[ns], nsap, nsaplen) < 0) { 824 Aerror(statp, stderr, "connect(dg)", errno, nsap, 825 nsaplen); 826 res_nclose(statp); 827 return (0); 828 } 829#endif /* !CANNOT_CONNECT_DGRAM */ 830 Dprint(statp->options & RES_DEBUG, 831 (stdout, ";; new DG socket\n")) 832 } 833 s = EXT(statp).nssocks[ns]; 834#ifndef CANNOT_CONNECT_DGRAM 835 if (send(s, (const char*)buf, buflen, 0) != buflen) { 836 Perror(statp, stderr, "send", errno); 837 res_nclose(statp); 838 return (0); 839 } 840#else /* !CANNOT_CONNECT_DGRAM */ 841 if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) 842 { 843 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen); 844 res_nclose(statp); 845 return (0); 846 } 847#endif /* !CANNOT_CONNECT_DGRAM */ 848 849 /* 850 * Wait for reply. 851 */ 852 seconds = (statp->retrans << ns); 853 if (ns > 0) 854 seconds /= statp->nscount; 855 if (seconds <= 0) 856 seconds = 1; 857 now = evNowTime(); 858 timeout = evConsTime(seconds, 0); 859 finish = evAddTime(now, timeout); 860 goto nonow; 861 wait: 862 now = evNowTime(); 863 nonow: 864#ifndef USE_POLL 865 FD_ZERO(&dsmask); 866 FD_SET(s, &dsmask); 867 if (evCmpTime(finish, now) > 0) 868 timeout = evSubTime(finish, now); 869 else 870 timeout = evConsTime(0, 0); 871 n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL); 872#else 873 timeout = evSubTime(finish, now); 874 if (timeout.tv_sec < 0) 875 timeout = evConsTime(0, 0); 876 polltimeout = 1000*timeout.tv_sec + 877 timeout.tv_nsec/1000000; 878 pollfd.fd = s; 879 pollfd.events = POLLRDNORM; 880 n = poll(&pollfd, 1, polltimeout); 881#endif /* USE_POLL */ 882 883 if (n == 0) { 884 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n")); 885 *gotsomewhere = 1; 886 return (0); 887 } 888 if (n < 0) { 889 if (errno == EINTR) 890 goto wait; 891#ifndef USE_POLL 892 Perror(statp, stderr, "select", errno); 893#else 894 Perror(statp, stderr, "poll", errno); 895#endif /* USE_POLL */ 896 res_nclose(statp); 897 return (0); 898 } 899 errno = 0; 900 fromlen = sizeof(from); 901 resplen = recvfrom(s, (char*)ans, anssiz,0, 902 (struct sockaddr *)&from, &fromlen); 903 if (resplen <= 0) { 904 Perror(statp, stderr, "recvfrom", errno); 905 res_nclose(statp); 906 return (0); 907 } 908 *gotsomewhere = 1; 909 if (resplen < HFIXEDSZ) { 910 /* 911 * Undersized message. 912 */ 913 Dprint(statp->options & RES_DEBUG, 914 (stdout, ";; undersized: %d\n", 915 resplen)); 916 *terrno = EMSGSIZE; 917 res_nclose(statp); 918 return (0); 919 } 920 if (hp->id != anhp->id) { 921 /* 922 * response from old query, ignore it. 923 * XXX - potential security hazard could 924 * be detected here. 925 */ 926 DprintQ((statp->options & RES_DEBUG) || 927 (statp->pfcode & RES_PRF_REPLY), 928 (stdout, ";; old answer:\n"), 929 ans, (resplen > anssiz) ? anssiz : resplen); 930 goto wait; 931 } 932 if (!(statp->options & RES_INSECURE1) && 933 !res_ourserver_p(statp, (struct sockaddr *)&from)) { 934 /* 935 * response from wrong server? ignore it. 936 * XXX - potential security hazard could 937 * be detected here. 938 */ 939 DprintQ((statp->options & RES_DEBUG) || 940 (statp->pfcode & RES_PRF_REPLY), 941 (stdout, ";; not our server:\n"), 942 ans, (resplen > anssiz) ? anssiz : resplen); 943 goto wait; 944 } 945#ifdef RES_USE_EDNS0 946 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) { 947 /* 948 * Do not retry if the server do not understand EDNS0. 949 * The case has to be captured here, as FORMERR packet do not 950 * carry query section, hence res_queriesmatch() returns 0. 951 */ 952 DprintQ(statp->options & RES_DEBUG, 953 (stdout, "server rejected query with EDNS0:\n"), 954 ans, (resplen > anssiz) ? anssiz : resplen); 955 /* record the error */ 956 statp->_flags |= RES_F_EDNS0ERR; 957 res_nclose(statp); 958 return (0); 959 } 960#endif 961 if (!(statp->options & RES_INSECURE2) && 962 !res_queriesmatch(buf, buf + buflen, 963 ans, ans + anssiz)) { 964 /* 965 * response contains wrong query? ignore it. 966 * XXX - potential security hazard could 967 * be detected here. 968 */ 969 DprintQ((statp->options & RES_DEBUG) || 970 (statp->pfcode & RES_PRF_REPLY), 971 (stdout, ";; wrong query name:\n"), 972 ans, (resplen > anssiz) ? anssiz : resplen); 973 goto wait; 974 } 975 if (anhp->rcode == SERVFAIL || 976 anhp->rcode == NOTIMP || 977 anhp->rcode == REFUSED) { 978 DprintQ(statp->options & RES_DEBUG, 979 (stdout, "server rejected query:\n"), 980 ans, (resplen > anssiz) ? anssiz : resplen); 981 res_nclose(statp); 982 /* don't retry if called from dig */ 983 if (!statp->pfcode) 984 return (0); 985 } 986 if (!(statp->options & RES_IGNTC) && anhp->tc) { 987 /* 988 * To get the rest of answer, 989 * use TCP with same server. 990 */ 991 Dprint(statp->options & RES_DEBUG, 992 (stdout, ";; truncated answer\n")); 993 *v_circuit = 1; 994 res_nclose(statp); 995 return (1); 996 } 997 /* 998 * All is well, or the error is fatal. Signal that the 999 * next nameserver ought not be tried. 1000 */ 1001 return (resplen); 1002} 1003 1004static void 1005Aerror(const res_state statp, FILE *file, const char *string, int error, 1006 const struct sockaddr *address, int alen) 1007{ 1008 int save = errno; 1009 char hbuf[NI_MAXHOST]; 1010 char sbuf[NI_MAXSERV]; 1011 1012 alen = alen; 1013 1014 if ((statp->options & RES_DEBUG) != 0U) { 1015 if (getnameinfo(address, alen, hbuf, sizeof(hbuf), 1016 sbuf, sizeof(sbuf), niflags)) { 1017 strncpy(hbuf, "?", sizeof(hbuf) - 1); 1018 hbuf[sizeof(hbuf) - 1] = '\0'; 1019 strncpy(sbuf, "?", sizeof(sbuf) - 1); 1020 sbuf[sizeof(sbuf) - 1] = '\0'; 1021 } 1022 fprintf(file, "res_send: %s ([%s].%s): %s\n", 1023 string, hbuf, sbuf, strerror(error)); 1024 } 1025 errno = save; 1026} 1027 1028static void 1029Perror(const res_state statp, FILE *file, const char *string, int error) { 1030 int save = errno; 1031 1032 if ((statp->options & RES_DEBUG) != 0U) 1033 fprintf(file, "res_send: %s: %s\n", 1034 string, strerror(error)); 1035 errno = save; 1036} 1037 1038static int 1039sock_eq(struct sockaddr *a, struct sockaddr *b) { 1040 struct sockaddr_in *a4, *b4; 1041 struct sockaddr_in6 *a6, *b6; 1042 1043 if (a->sa_family != b->sa_family) 1044 return 0; 1045 switch (a->sa_family) { 1046 case AF_INET: 1047 a4 = (struct sockaddr_in *)a; 1048 b4 = (struct sockaddr_in *)b; 1049 return a4->sin_port == b4->sin_port && 1050 a4->sin_addr.s_addr == b4->sin_addr.s_addr; 1051 case AF_INET6: 1052 a6 = (struct sockaddr_in6 *)a; 1053 b6 = (struct sockaddr_in6 *)b; 1054 return a6->sin6_port == b6->sin6_port && 1055#ifdef HAVE_SIN6_SCOPE_ID 1056 a6->sin6_scope_id == b6->sin6_scope_id && 1057#endif 1058 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr); 1059 default: 1060 return 0; 1061 } 1062} 1063 1064#if defined(NEED_PSELECT) && !defined(USE_POLL) 1065/* XXX needs to move to the porting library. */ 1066static int 1067pselect(int nfds, void *rfds, void *wfds, void *efds, 1068 struct timespec *tsp, const sigset_t *sigmask) 1069{ 1070 struct timeval tv, *tvp; 1071 sigset_t sigs; 1072 int n; 1073 1074 if (tsp) { 1075 tvp = &tv; 1076 tv = evTimeVal(*tsp); 1077 } else 1078 tvp = NULL; 1079 if (sigmask) 1080 sigprocmask(SIG_SETMASK, sigmask, &sigs); 1081 n = select(nfds, rfds, wfds, efds, tvp); 1082 if (sigmask) 1083 sigprocmask(SIG_SETMASK, &sigs, NULL); 1084 if (tsp) 1085 *tsp = evTimeSpec(tv); 1086 return (n); 1087} 1088#endif 1089