some coverity fixes.
[minix.git] / lib / libc / resolv / res_send.c
blob8e8bbb193607343d23e7689206ad00bfdc4b2b3c
1 /* $NetBSD: res_send.c,v 1.20 2009/10/24 17:24:01 christos Exp $ */
3 /*
4 * Portions Copyright (C) 2004-2009 Internet Systems Consortium, Inc. ("ISC")
5 * Portions Copyright (C) 1996-2003 Internet Software Consortium.
7 * Permission to use, copy, modify, and/or distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
12 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
13 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
14 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
15 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
16 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
17 * PERFORMANCE OF THIS SOFTWARE.
21 * Copyright (c) 1985, 1989, 1993
22 * The Regents of the University of California. All rights reserved.
24 * Redistribution and use in source and binary forms, with or without
25 * modification, are permitted provided that the following conditions
26 * are met:
27 * 1. Redistributions of source code must retain the above copyright
28 * notice, this list of conditions and the following disclaimer.
29 * 2. Redistributions in binary form must reproduce the above copyright
30 * notice, this list of conditions and the following disclaimer in the
31 * documentation and/or other materials provided with the distribution.
32 * 3. All advertising materials mentioning features or use of this software
33 * must display the following acknowledgement:
34 * This product includes software developed by the University of
35 * California, Berkeley and its contributors.
36 * 4. Neither the name of the University nor the names of its contributors
37 * may be used to endorse or promote products derived from this software
38 * without specific prior written permission.
40 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
54 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
56 * Permission to use, copy, modify, and distribute this software for any
57 * purpose with or without fee is hereby granted, provided that the above
58 * copyright notice and this permission notice appear in all copies, and that
59 * the name of Digital Equipment Corporation not be used in advertising or
60 * publicity pertaining to distribution of the document or software without
61 * specific, written prior permission.
63 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
64 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
65 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
66 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
67 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
68 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
69 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
70 * SOFTWARE.
74 * Copyright (c) 2005 by Internet Systems Consortium, Inc. ("ISC")
75 * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
77 * Permission to use, copy, modify, and distribute this software for any
78 * purpose with or without fee is hereby granted, provided that the above
79 * copyright notice and this permission notice appear in all copies.
81 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
82 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
83 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
84 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
85 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
86 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
87 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
90 #include <sys/cdefs.h>
91 #if defined(LIBC_SCCS) && !defined(lint)
92 #ifdef notdef
93 static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
94 static const char rcsid[] = "Id: res_send.c,v 1.22 2009/01/22 23:49:23 tbox Exp";
95 #else
96 __RCSID("$NetBSD: res_send.c,v 1.20 2009/10/24 17:24:01 christos Exp $");
97 #endif
98 #endif /* LIBC_SCCS and not lint */
100 /*! \file
101 * \brief
102 * Send query to name server and wait for reply.
105 #include "namespace.h"
106 #include "port_before.h"
107 #include "fd_setsize.h"
109 #include <sys/types.h>
110 #include <sys/param.h>
111 #include <sys/time.h>
112 #include <sys/socket.h>
113 #include <sys/uio.h>
115 #include <netinet/in.h>
116 #include <arpa/nameser.h>
117 #include <arpa/inet.h>
119 #include <errno.h>
120 #include <netdb.h>
121 #include <resolv.h>
122 #include <signal.h>
123 #include <stdio.h>
124 #include <stdlib.h>
125 #include <string.h>
126 #include <unistd.h>
128 #include <isc/eventlib.h>
130 #include "port_after.h"
132 #if 0
133 #ifdef __weak_alias
134 __weak_alias(res_ourserver_p,__res_ourserver_p)
135 __weak_alias(res_nameinquery,__res_nameinquery)
136 __weak_alias(res_queriesmatch,__res_queriesmatch)
137 __weak_alias(res_nsend,__res_nsend)
138 #endif
139 #endif
142 #ifdef USE_POLL
143 #ifdef HAVE_STROPTS_H
144 #include <stropts.h>
145 #endif
146 #include <poll.h>
147 #endif /* USE_POLL */
149 /* Options. Leave them on. */
150 #ifndef DEBUG
151 #define DEBUG
152 #endif
153 #include "res_debug.h"
154 #include "res_private.h"
156 #define EXT(res) ((res)->_u._ext)
158 #ifndef USE_POLL
159 static const int highestFD = FD_SETSIZE - 1;
160 #else
161 static int highestFD = 0;
162 #endif
164 /* Forward. */
166 static int get_salen __P((const struct sockaddr *));
167 static struct sockaddr * get_nsaddr __P((res_state, size_t));
168 static int send_vc(res_state, const u_char *, int,
169 u_char *, int, int *, int);
170 static int send_dg(res_state, const u_char *, int,
171 u_char *, int, int *, int, int,
172 int *, int *);
173 static void Aerror(const res_state, FILE *, const char *, int,
174 const struct sockaddr *, int);
175 static void Perror(const res_state, FILE *, const char *, int);
176 static int sock_eq(struct sockaddr *, struct sockaddr *);
177 #if defined(NEED_PSELECT) && !defined(USE_POLL)
178 static int pselect(int, void *, void *, void *,
179 struct timespec *,
180 const sigset_t *);
181 #endif
182 void res_pquery(const res_state, const u_char *, int, FILE *);
184 static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
186 /* Public. */
189 * looks up "ina" in _res.ns_addr_list[]
191 * returns:
192 *\li 0 : not found
193 *\li >0 : found
195 * author:
196 *\li paul vixie, 29may94
199 res_ourserver_p(const res_state statp, const struct sockaddr *sa) {
200 const struct sockaddr_in *inp, *srv;
201 const struct sockaddr_in6 *in6p, *srv6;
202 int ns;
204 switch (sa->sa_family) {
205 case AF_INET:
206 inp = (const struct sockaddr_in *)(const void *)sa;
207 for (ns = 0; ns < statp->nscount; ns++) {
208 srv = (struct sockaddr_in *)(void *)get_nsaddr(statp, (size_t)ns);
209 if (srv->sin_family == inp->sin_family &&
210 srv->sin_port == inp->sin_port &&
211 (srv->sin_addr.s_addr == INADDR_ANY ||
212 srv->sin_addr.s_addr == inp->sin_addr.s_addr))
213 return (1);
215 break;
216 case AF_INET6:
217 if (EXT(statp).ext == NULL)
218 break;
219 in6p = (const struct sockaddr_in6 *)(const void *)sa;
220 for (ns = 0; ns < statp->nscount; ns++) {
221 srv6 = (struct sockaddr_in6 *)(void *)get_nsaddr(statp, (size_t)ns);
222 if (srv6->sin6_family == in6p->sin6_family &&
223 srv6->sin6_port == in6p->sin6_port &&
224 #ifdef HAVE_SIN6_SCOPE_ID
225 (srv6->sin6_scope_id == 0 ||
226 srv6->sin6_scope_id == in6p->sin6_scope_id) &&
227 #endif
228 (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) ||
229 IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr)))
230 return (1);
232 break;
233 default:
234 break;
236 return (0);
240 * look for (name,type,class) in the query section of packet (buf,eom)
242 * requires:
243 *\li buf + HFIXEDSZ <= eom
245 * returns:
246 *\li -1 : format error
247 *\li 0 : not found
248 *\li >0 : found
250 * author:
251 *\li paul vixie, 29may94
254 res_nameinquery(const char *name, int type, int class,
255 const u_char *buf, const u_char *eom)
257 const u_char *cp = buf + HFIXEDSZ;
258 int qdcount = ntohs(((const HEADER*)(const void *)buf)->qdcount);
260 while (qdcount-- > 0) {
261 char tname[MAXDNAME+1];
262 int n, ttype, tclass;
264 n = dn_expand(buf, eom, cp, tname, sizeof tname);
265 if (n < 0)
266 return (-1);
267 cp += n;
268 if (cp + 2 * INT16SZ > eom)
269 return (-1);
270 ttype = ns_get16(cp); cp += INT16SZ;
271 tclass = ns_get16(cp); cp += INT16SZ;
272 if (ttype == type && tclass == class &&
273 ns_samename(tname, name) == 1)
274 return (1);
276 return (0);
280 * is there a 1:1 mapping of (name,type,class)
281 * in (buf1,eom1) and (buf2,eom2)?
283 * returns:
284 *\li -1 : format error
285 *\li 0 : not a 1:1 mapping
286 *\li >0 : is a 1:1 mapping
288 * author:
289 *\li paul vixie, 29may94
292 res_queriesmatch(const u_char *buf1, const u_char *eom1,
293 const u_char *buf2, const u_char *eom2)
295 const u_char *cp = buf1 + HFIXEDSZ;
296 int qdcount = ntohs(((const HEADER*)(const void *)buf1)->qdcount);
298 if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
299 return (-1);
302 * Only header section present in replies to
303 * dynamic update packets.
305 if ((((const HEADER *)(const void *)buf1)->opcode == ns_o_update) &&
306 (((const HEADER *)(const void *)buf2)->opcode == ns_o_update))
307 return (1);
309 if (qdcount != ntohs(((const HEADER*)(const void *)buf2)->qdcount))
310 return (0);
311 while (qdcount-- > 0) {
312 char tname[MAXDNAME+1];
313 int n, ttype, tclass;
315 n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
316 if (n < 0)
317 return (-1);
318 cp += n;
319 if (cp + 2 * INT16SZ > eom1)
320 return (-1);
321 ttype = ns_get16(cp); cp += INT16SZ;
322 tclass = ns_get16(cp); cp += INT16SZ;
323 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
324 return (0);
326 return (1);
330 res_nsend(res_state statp,
331 const u_char *buf, int buflen, u_char *ans, int anssiz)
333 int gotsomewhere, terrno, tries, v_circuit, resplen, ns, n;
334 char abuf[NI_MAXHOST];
336 #ifdef USE_POLL
337 highestFD = sysconf(_SC_OPEN_MAX) - 1;
338 #endif
340 (void)res_check(statp, NULL);
342 /* No name servers or res_init() failure */
343 if (statp->nscount == 0 || EXT(statp).ext == NULL) {
344 errno = ESRCH;
345 return (-1);
347 if (anssiz < HFIXEDSZ) {
348 errno = EINVAL;
349 return (-1);
351 DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY),
352 (stdout, ";; res_send()\n"), buf, buflen);
353 v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ;
354 gotsomewhere = 0;
355 terrno = ETIMEDOUT;
358 * If the ns_addr_list in the resolver context has changed, then
359 * invalidate our cached copy and the associated timing data.
361 if (EXT(statp).nscount != 0) {
362 int needclose = 0;
363 struct sockaddr_storage peer;
364 ISC_SOCKLEN_T peerlen;
366 if (EXT(statp).nscount != statp->nscount)
367 needclose++;
368 else
369 for (ns = 0; ns < statp->nscount; ns++) {
370 if (statp->nsaddr_list[ns].sin_family &&
371 !sock_eq((struct sockaddr *)(void *)&statp->nsaddr_list[ns],
372 (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[ns])) {
373 needclose++;
374 break;
377 if (EXT(statp).nssocks[ns] == -1)
378 continue;
379 peerlen = sizeof(peer);
380 if (getpeername(EXT(statp).nssocks[ns],
381 (struct sockaddr *)(void *)&peer, &peerlen) < 0) {
382 needclose++;
383 break;
385 if (!sock_eq((struct sockaddr *)(void *)&peer,
386 get_nsaddr(statp, (size_t)ns))) {
387 needclose++;
388 break;
391 if (needclose) {
392 res_nclose(statp);
393 EXT(statp).nscount = 0;
398 * Maybe initialize our private copy of the ns_addr_list.
400 if (EXT(statp).nscount == 0) {
401 for (ns = 0; ns < statp->nscount; ns++) {
402 EXT(statp).nstimes[ns] = RES_MAXTIME;
403 EXT(statp).nssocks[ns] = -1;
404 if (!statp->nsaddr_list[ns].sin_family)
405 continue;
406 EXT(statp).ext->nsaddrs[ns].sin =
407 statp->nsaddr_list[ns];
409 EXT(statp).nscount = statp->nscount;
413 * Some resolvers want to even out the load on their nameservers.
414 * Note that RES_BLAST overrides RES_ROTATE.
416 if ((statp->options & RES_ROTATE) != 0U &&
417 (statp->options & RES_BLAST) == 0U) {
418 union res_sockaddr_union inu;
419 struct sockaddr_in ina;
420 int lastns = statp->nscount - 1;
421 int fd;
422 u_int16_t nstime;
424 if (EXT(statp).ext != NULL)
425 inu = EXT(statp).ext->nsaddrs[0];
426 ina = statp->nsaddr_list[0];
427 fd = EXT(statp).nssocks[0];
428 nstime = EXT(statp).nstimes[0];
429 for (ns = 0; ns < lastns; ns++) {
430 if (EXT(statp).ext != NULL)
431 EXT(statp).ext->nsaddrs[ns] =
432 EXT(statp).ext->nsaddrs[ns + 1];
433 statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1];
434 EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1];
435 EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1];
437 if (EXT(statp).ext != NULL)
438 EXT(statp).ext->nsaddrs[lastns] = inu;
439 statp->nsaddr_list[lastns] = ina;
440 EXT(statp).nssocks[lastns] = fd;
441 EXT(statp).nstimes[lastns] = nstime;
445 * Send request, RETRY times, or until successful.
447 for (tries = 0; tries < statp->retry; tries++) {
448 for (ns = 0; ns < statp->nscount; ns++) {
449 struct sockaddr *nsap;
450 int nsaplen;
451 nsap = get_nsaddr(statp, (size_t)ns);
452 nsaplen = get_salen(nsap);
453 statp->_flags &= ~RES_F_LASTMASK;
454 statp->_flags |= (ns << RES_F_LASTSHIFT);
455 same_ns:
456 if (statp->qhook) {
457 int done = 0, loops = 0;
459 do {
460 res_sendhookact act;
462 act = (*statp->qhook)(&nsap, &buf, &buflen,
463 ans, anssiz, &resplen);
464 switch (act) {
465 case res_goahead:
466 done = 1;
467 break;
468 case res_nextns:
469 res_nclose(statp);
470 goto next_ns;
471 case res_done:
472 return (resplen);
473 case res_modified:
474 /* give the hook another try */
475 if (++loops < 42) /*doug adams*/
476 break;
477 /*FALLTHROUGH*/
478 case res_error:
479 /*FALLTHROUGH*/
480 default:
481 goto fail;
483 } while (!done);
486 Dprint(((statp->options & RES_DEBUG) &&
487 getnameinfo(nsap, (socklen_t)nsaplen, abuf, sizeof(abuf),
488 NULL, 0, niflags) == 0),
489 (stdout, ";; Querying server (# %d) address = %s\n",
490 ns + 1, abuf));
493 if (v_circuit) {
494 /* Use VC; at most one attempt per server. */
495 tries = statp->retry;
496 n = send_vc(statp, buf, buflen, ans, anssiz, &terrno,
497 ns);
498 if (n < 0)
499 goto fail;
500 if (n == 0)
501 goto next_ns;
502 resplen = n;
503 } else {
504 /* Use datagrams. */
505 n = send_dg(statp, buf, buflen, ans, anssiz, &terrno,
506 ns, tries, &v_circuit, &gotsomewhere);
507 if (n < 0)
508 goto fail;
509 if (n == 0)
510 goto next_ns;
511 if (v_circuit)
512 goto same_ns;
513 resplen = n;
516 Dprint((statp->options & RES_DEBUG) ||
517 ((statp->pfcode & RES_PRF_REPLY) &&
518 (statp->pfcode & RES_PRF_HEAD1)),
519 (stdout, ";; got answer:\n"));
521 DprintQ((statp->options & RES_DEBUG) ||
522 (statp->pfcode & RES_PRF_REPLY),
523 (stdout, "%s", ""),
524 ans, (resplen > anssiz) ? anssiz : resplen);
527 * If we have temporarily opened a virtual circuit,
528 * or if we haven't been asked to keep a socket open,
529 * close the socket.
531 if ((v_circuit && (statp->options & RES_USEVC) == 0U) ||
532 (statp->options & RES_STAYOPEN) == 0U) {
533 res_nclose(statp);
535 if (statp->rhook) {
536 int done = 0, loops = 0;
538 do {
539 res_sendhookact act;
541 act = (*statp->rhook)(nsap, buf, buflen,
542 ans, anssiz, &resplen);
543 switch (act) {
544 case res_goahead:
545 case res_done:
546 done = 1;
547 break;
548 case res_nextns:
549 res_nclose(statp);
550 goto next_ns;
551 case res_modified:
552 /* give the hook another try */
553 if (++loops < 42) /*doug adams*/
554 break;
555 /*FALLTHROUGH*/
556 case res_error:
557 /*FALLTHROUGH*/
558 default:
559 goto fail;
561 } while (!done);
564 return (resplen);
565 next_ns: ;
566 } /*foreach ns*/
567 } /*foreach retry*/
568 res_nclose(statp);
569 if (!v_circuit) {
570 if (!gotsomewhere)
571 errno = ECONNREFUSED; /*%< no nameservers found */
572 else
573 errno = ETIMEDOUT; /*%< no answer obtained */
574 } else
575 errno = terrno;
576 return (-1);
577 fail:
578 res_nclose(statp);
579 return (-1);
582 /* Private */
584 static int
585 get_salen(sa)
586 const struct sockaddr *sa;
589 #ifdef HAVE_SA_LEN
590 /* There are people do not set sa_len. Be forgiving to them. */
591 if (sa->sa_len)
592 return (sa->sa_len);
593 #endif
595 if (sa->sa_family == AF_INET)
596 return (sizeof(struct sockaddr_in));
597 else if (sa->sa_family == AF_INET6)
598 return (sizeof(struct sockaddr_in6));
599 else
600 return (0); /*%< unknown, die on connect */
604 * pick appropriate nsaddr_list for use. see res_init() for initialization.
606 static struct sockaddr *
607 get_nsaddr(statp, n)
608 res_state statp;
609 size_t n;
612 if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) {
614 * - EXT(statp).ext->nsaddrs[n] holds an address that is larger
615 * than struct sockaddr, and
616 * - user code did not update statp->nsaddr_list[n].
618 return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n];
619 } else {
621 * - user code updated statp->nsaddr_list[n], or
622 * - statp->nsaddr_list[n] has the same content as
623 * EXT(statp).ext->nsaddrs[n].
625 return (struct sockaddr *)(void *)&statp->nsaddr_list[n];
629 static int
630 send_vc(res_state statp,
631 const u_char *buf, int buflen, u_char *ans, int anssiz,
632 int *terrno, int ns)
634 const HEADER *hp = (const HEADER *)(const void *)buf;
635 HEADER *anhp = (HEADER *)(void *)ans;
636 struct sockaddr *nsap;
637 int nsaplen;
638 int truncating, connreset, resplen, n;
639 struct iovec iov[2];
640 u_short len;
641 u_char *cp;
642 void *tmp;
643 #ifdef SO_NOSIGPIPE
644 int on = 1;
645 #endif
647 nsap = get_nsaddr(statp, (size_t)ns);
648 nsaplen = get_salen(nsap);
650 connreset = 0;
651 same_ns:
652 truncating = 0;
654 /* Are we still talking to whom we want to talk to? */
655 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) {
656 struct sockaddr_storage peer;
657 ISC_SOCKLEN_T size = sizeof peer;
659 if (getpeername(statp->_vcsock,
660 (struct sockaddr *)(void *)&peer, &size) < 0 ||
661 !sock_eq((struct sockaddr *)(void *)&peer, nsap)) {
662 res_nclose(statp);
663 statp->_flags &= ~RES_F_VC;
667 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) {
668 if (statp->_vcsock >= 0)
669 res_nclose(statp);
671 statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM, 0);
672 if (statp->_vcsock > highestFD) {
673 res_nclose(statp);
674 errno = ENOTSOCK;
676 if (statp->_vcsock < 0) {
677 switch (errno) {
678 case EPROTONOSUPPORT:
679 #ifdef EPFNOSUPPORT
680 case EPFNOSUPPORT:
681 #endif
682 case EAFNOSUPPORT:
683 Perror(statp, stderr, "socket(vc)", errno);
684 return (0);
685 default:
686 *terrno = errno;
687 Perror(statp, stderr, "socket(vc)", errno);
688 return (-1);
691 #ifdef SO_NOSIGPIPE
693 * Disable generation of SIGPIPE when writing to a closed
694 * socket. Write should return -1 and set errno to EPIPE
695 * instead.
697 * Push on even if setsockopt(SO_NOSIGPIPE) fails.
699 (void)setsockopt(statp->_vcsock, SOL_SOCKET, SO_NOSIGPIPE, &on,
700 sizeof(on));
701 #endif
702 errno = 0;
703 if (connect(statp->_vcsock, nsap, (socklen_t)nsaplen) < 0) {
704 *terrno = errno;
705 Aerror(statp, stderr, "connect/vc", errno, nsap,
706 nsaplen);
707 res_nclose(statp);
708 return (0);
710 statp->_flags |= RES_F_VC;
714 * Send length & message
716 ns_put16((u_short)buflen, (u_char*)(void *)&len);
717 iov[0] = evConsIovec(&len, INT16SZ);
718 DE_CONST(buf, tmp);
719 iov[1] = evConsIovec(tmp, (size_t)buflen);
720 if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) {
721 *terrno = errno;
722 Perror(statp, stderr, "write failed", errno);
723 res_nclose(statp);
724 return (0);
727 * Receive length & response
729 read_len:
730 cp = ans;
731 len = INT16SZ;
732 while ((n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0) {
733 cp += n;
734 if ((len -= n) == 0)
735 break;
737 if (n <= 0) {
738 *terrno = errno;
739 Perror(statp, stderr, "read failed", errno);
740 res_nclose(statp);
742 * A long running process might get its TCP
743 * connection reset if the remote server was
744 * restarted. Requery the server instead of
745 * trying a new one. When there is only one
746 * server, this means that a query might work
747 * instead of failing. We only allow one reset
748 * per query to prevent looping.
750 if (*terrno == ECONNRESET && !connreset) {
751 connreset = 1;
752 res_nclose(statp);
753 goto same_ns;
755 res_nclose(statp);
756 return (0);
758 resplen = ns_get16(ans);
759 if (resplen > anssiz) {
760 Dprint(statp->options & RES_DEBUG,
761 (stdout, ";; response truncated\n")
763 truncating = 1;
764 len = anssiz;
765 } else
766 len = resplen;
767 if (len < HFIXEDSZ) {
769 * Undersized message.
771 Dprint(statp->options & RES_DEBUG,
772 (stdout, ";; undersized: %d\n", len));
773 *terrno = EMSGSIZE;
774 res_nclose(statp);
775 return (0);
777 cp = ans;
778 while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0){
779 cp += n;
780 len -= n;
782 if (n <= 0) {
783 *terrno = errno;
784 Perror(statp, stderr, "read(vc)", errno);
785 res_nclose(statp);
786 return (0);
788 if (truncating) {
790 * Flush rest of answer so connection stays in synch.
792 anhp->tc = 1;
793 len = resplen - anssiz;
794 while (len != 0) {
795 char junk[PACKETSZ];
797 n = read(statp->_vcsock, junk,
798 (len > sizeof junk) ? sizeof junk : len);
799 if (n > 0)
800 len -= n;
801 else
802 break;
806 * If the calling applicating has bailed out of
807 * a previous call and failed to arrange to have
808 * the circuit closed or the server has got
809 * itself confused, then drop the packet and
810 * wait for the correct one.
812 if (hp->id != anhp->id) {
813 DprintQ((statp->options & RES_DEBUG) ||
814 (statp->pfcode & RES_PRF_REPLY),
815 (stdout, ";; old answer (unexpected):\n"),
816 ans, (resplen > anssiz) ? anssiz: resplen);
817 goto read_len;
821 * All is well, or the error is fatal. Signal that the
822 * next nameserver ought not be tried.
824 return (resplen);
827 static int
828 send_dg(res_state statp, const u_char *buf, int buflen, u_char *ans,
829 int anssiz, int *terrno, int ns, int tries, int *v_circuit,
830 int *gotsomewhere)
832 const HEADER *hp = (const HEADER *)(const void *)buf;
833 HEADER *anhp = (HEADER *)(void *)ans;
834 const struct sockaddr *nsap;
835 int nsaplen;
836 struct timespec now, timeout, finish;
837 struct sockaddr_storage from;
838 ISC_SOCKLEN_T fromlen;
839 int resplen, seconds, n, s;
840 #ifdef USE_POLL
841 int polltimeout;
842 struct pollfd pollfd;
843 #else
844 fd_set dsmask;
845 #endif
847 nsap = get_nsaddr(statp, (size_t)ns);
848 nsaplen = get_salen(nsap);
849 if (EXT(statp).nssocks[ns] == -1) {
850 EXT(statp).nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM, 0);
851 if (EXT(statp).nssocks[ns] > highestFD) {
852 res_nclose(statp);
853 errno = ENOTSOCK;
855 if (EXT(statp).nssocks[ns] < 0) {
856 switch (errno) {
857 case EPROTONOSUPPORT:
858 #ifdef EPFNOSUPPORT
859 case EPFNOSUPPORT:
860 #endif
861 case EAFNOSUPPORT:
862 Perror(statp, stderr, "socket(dg)", errno);
863 return (0);
864 default:
865 *terrno = errno;
866 Perror(statp, stderr, "socket(dg)", errno);
867 return (-1);
870 #ifndef CANNOT_CONNECT_DGRAM
872 * On a 4.3BSD+ machine (client and server,
873 * actually), sending to a nameserver datagram
874 * port with no nameserver will cause an
875 * ICMP port unreachable message to be returned.
876 * If our datagram socket is "connected" to the
877 * server, we get an ECONNREFUSED error on the next
878 * socket operation, and select returns if the
879 * error message is received. We can thus detect
880 * the absence of a nameserver without timing out.
882 if (connect(EXT(statp).nssocks[ns], nsap, (socklen_t)nsaplen) < 0) {
883 Aerror(statp, stderr, "connect(dg)", errno, nsap,
884 nsaplen);
885 res_nclose(statp);
886 return (0);
888 #endif /* !CANNOT_CONNECT_DGRAM */
889 Dprint(statp->options & RES_DEBUG,
890 (stdout, ";; new DG socket\n"))
892 s = EXT(statp).nssocks[ns];
893 #ifndef CANNOT_CONNECT_DGRAM
894 if (send(s, (const char*)buf, (size_t)buflen, 0) != buflen) {
895 Perror(statp, stderr, "send", errno);
896 res_nclose(statp);
897 return (0);
899 #else /* !CANNOT_CONNECT_DGRAM */
900 if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen)
902 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen);
903 res_nclose(statp);
904 return (0);
906 #endif /* !CANNOT_CONNECT_DGRAM */
909 * Wait for reply.
911 seconds = (statp->retrans << tries);
912 if (ns > 0)
913 seconds /= statp->nscount;
914 if (seconds <= 0)
915 seconds = 1;
916 now = evNowTime();
917 timeout = evConsTime((long)seconds, 0L);
918 finish = evAddTime(now, timeout);
919 goto nonow;
920 wait:
921 now = evNowTime();
922 nonow:
923 #ifndef USE_POLL
924 FD_ZERO(&dsmask);
925 FD_SET(s, &dsmask);
926 if (evCmpTime(finish, now) > 0)
927 timeout = evSubTime(finish, now);
928 else
929 timeout = evConsTime(0L, 0L);
930 n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL);
931 #else
932 timeout = evSubTime(finish, now);
933 if (timeout.tv_sec < 0)
934 timeout = evConsTime(0L, 0L);
935 polltimeout = 1000*(int)timeout.tv_sec +
936 (int)timeout.tv_nsec/1000000;
937 pollfd.fd = s;
938 pollfd.events = POLLRDNORM;
939 n = poll(&pollfd, 1, polltimeout);
940 #endif /* USE_POLL */
942 if (n == 0) {
943 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n"));
944 *gotsomewhere = 1;
945 return (0);
947 if (n < 0) {
948 if (errno == EINTR)
949 goto wait;
950 #ifndef USE_POLL
951 Perror(statp, stderr, "select", errno);
952 #else
953 Perror(statp, stderr, "poll", errno);
954 #endif /* USE_POLL */
955 res_nclose(statp);
956 return (0);
958 errno = 0;
959 fromlen = sizeof(from);
960 resplen = recvfrom(s, (char*)ans, (size_t)anssiz,0,
961 (struct sockaddr *)(void *)&from, &fromlen);
962 if (resplen <= 0) {
963 Perror(statp, stderr, "recvfrom", errno);
964 res_nclose(statp);
965 return (0);
967 *gotsomewhere = 1;
968 if (resplen < HFIXEDSZ) {
970 * Undersized message.
972 Dprint(statp->options & RES_DEBUG,
973 (stdout, ";; undersized: %d\n",
974 resplen));
975 *terrno = EMSGSIZE;
976 res_nclose(statp);
977 return (0);
979 if (hp->id != anhp->id) {
981 * response from old query, ignore it.
982 * XXX - potential security hazard could
983 * be detected here.
985 DprintQ((statp->options & RES_DEBUG) ||
986 (statp->pfcode & RES_PRF_REPLY),
987 (stdout, ";; old answer:\n"),
988 ans, (resplen > anssiz) ? anssiz : resplen);
989 goto wait;
991 if (!(statp->options & RES_INSECURE1) &&
992 !res_ourserver_p(statp, (struct sockaddr *)(void *)&from)) {
994 * response from wrong server? ignore it.
995 * XXX - potential security hazard could
996 * be detected here.
998 DprintQ((statp->options & RES_DEBUG) ||
999 (statp->pfcode & RES_PRF_REPLY),
1000 (stdout, ";; not our server:\n"),
1001 ans, (resplen > anssiz) ? anssiz : resplen);
1002 goto wait;
1004 #ifdef RES_USE_EDNS0
1005 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) {
1007 * Do not retry if the server do not understand EDNS0.
1008 * The case has to be captured here, as FORMERR packet do not
1009 * carry query section, hence res_queriesmatch() returns 0.
1011 DprintQ(statp->options & RES_DEBUG,
1012 (stdout, "server rejected query with EDNS0:\n"),
1013 ans, (resplen > anssiz) ? anssiz : resplen);
1014 /* record the error */
1015 statp->_flags |= RES_F_EDNS0ERR;
1016 res_nclose(statp);
1017 return (0);
1019 #endif
1020 if (!(statp->options & RES_INSECURE2) &&
1021 !res_queriesmatch(buf, buf + buflen,
1022 ans, ans + anssiz)) {
1024 * response contains wrong query? ignore it.
1025 * XXX - potential security hazard could
1026 * be detected here.
1028 DprintQ((statp->options & RES_DEBUG) ||
1029 (statp->pfcode & RES_PRF_REPLY),
1030 (stdout, ";; wrong query name:\n"),
1031 ans, (resplen > anssiz) ? anssiz : resplen);
1032 goto wait;
1034 if (anhp->rcode == SERVFAIL ||
1035 anhp->rcode == NOTIMP ||
1036 anhp->rcode == REFUSED) {
1037 DprintQ(statp->options & RES_DEBUG,
1038 (stdout, "server rejected query:\n"),
1039 ans, (resplen > anssiz) ? anssiz : resplen);
1040 res_nclose(statp);
1041 /* don't retry if called from dig */
1042 if (!statp->pfcode)
1043 return (0);
1045 if (!(statp->options & RES_IGNTC) && anhp->tc) {
1047 * To get the rest of answer,
1048 * use TCP with same server.
1050 Dprint(statp->options & RES_DEBUG,
1051 (stdout, ";; truncated answer\n"));
1052 *v_circuit = 1;
1053 res_nclose(statp);
1054 return (1);
1057 * All is well, or the error is fatal. Signal that the
1058 * next nameserver ought not be tried.
1060 return (resplen);
1063 static void
1064 Aerror(const res_state statp, FILE *file, const char *string, int error,
1065 const struct sockaddr *address, int alen)
1067 int save = errno;
1068 char hbuf[NI_MAXHOST];
1069 char sbuf[NI_MAXSERV];
1071 if ((statp->options & RES_DEBUG) != 0U) {
1072 if (getnameinfo(address, (socklen_t)alen, hbuf, sizeof(hbuf),
1073 sbuf, sizeof(sbuf), niflags)) {
1074 strncpy(hbuf, "?", sizeof(hbuf) - 1);
1075 hbuf[sizeof(hbuf) - 1] = '\0';
1076 strncpy(sbuf, "?", sizeof(sbuf) - 1);
1077 sbuf[sizeof(sbuf) - 1] = '\0';
1079 fprintf(file, "res_send: %s ([%s].%s): %s\n",
1080 string, hbuf, sbuf, strerror(error));
1082 errno = save;
1085 static void
1086 Perror(const res_state statp, FILE *file, const char *string, int error) {
1087 int save = errno;
1089 if ((statp->options & RES_DEBUG) != 0U)
1090 fprintf(file, "res_send: %s: %s\n",
1091 string, strerror(error));
1092 errno = save;
1095 static int
1096 sock_eq(struct sockaddr *a, struct sockaddr *b) {
1097 struct sockaddr_in *a4, *b4;
1098 struct sockaddr_in6 *a6, *b6;
1100 if (a->sa_family != b->sa_family)
1101 return 0;
1102 switch (a->sa_family) {
1103 case AF_INET:
1104 a4 = (struct sockaddr_in *)(void *)a;
1105 b4 = (struct sockaddr_in *)(void *)b;
1106 return a4->sin_port == b4->sin_port &&
1107 a4->sin_addr.s_addr == b4->sin_addr.s_addr;
1108 case AF_INET6:
1109 a6 = (struct sockaddr_in6 *)(void *)a;
1110 b6 = (struct sockaddr_in6 *)(void *)b;
1111 return a6->sin6_port == b6->sin6_port &&
1112 #ifdef HAVE_SIN6_SCOPE_ID
1113 a6->sin6_scope_id == b6->sin6_scope_id &&
1114 #endif
1115 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr);
1116 default:
1117 return 0;
1121 #if defined(NEED_PSELECT) && !defined(USE_POLL)
1122 /* XXX needs to move to the porting library. */
1123 static int
1124 pselect(int nfds, void *rfds, void *wfds, void *efds,
1125 struct timespec *tsp, const sigset_t *sigmask)
1127 struct timeval tv, *tvp;
1128 sigset_t sigs;
1129 int n;
1131 if (tsp) {
1132 tvp = &tv;
1133 tv = evTimeVal(*tsp);
1134 } else
1135 tvp = NULL;
1136 if (sigmask)
1137 sigprocmask(SIG_SETMASK, sigmask, &sigs);
1138 n = select(nfds, rfds, wfds, efds, tvp);
1139 if (sigmask)
1140 sigprocmask(SIG_SETMASK, &sigs, NULL);
1141 if (tsp)
1142 *tsp = evTimeSpec(tv);
1143 return (n);
1145 #endif