* manual/charset.texi (Converting a Character): Fix example code so a
[glibc.git] / resolv / res_send.c
blob19adc3e10325da0ec15672e972f119af31e098e0
1 /*
2 * Copyright (c) 1985, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
31 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
33 * Permission to use, copy, modify, and distribute this software for any
34 * purpose with or without fee is hereby granted, provided that the above
35 * copyright notice and this permission notice appear in all copies, and that
36 * the name of Digital Equipment Corporation not be used in advertising or
37 * publicity pertaining to distribution of the document or software without
38 * specific, written prior permission.
40 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
41 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
42 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
43 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
44 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
45 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
46 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
47 * SOFTWARE.
51 * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
53 * Permission to use, copy, modify, and distribute this software for any
54 * purpose with or without fee is hereby granted, provided that the above
55 * copyright notice and this permission notice appear in all copies.
57 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
58 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
59 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
60 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
61 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
62 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
63 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
64 * SOFTWARE.
67 #if defined(LIBC_SCCS) && !defined(lint)
68 static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
69 static const char rcsid[] = "$BINDId: res_send.c,v 8.38 2000/03/30 20:16:51 vixie Exp $";
70 #endif /* LIBC_SCCS and not lint */
73 * Send query to name server and wait for reply.
76 #include <sys/types.h>
77 #include <sys/param.h>
78 #include <sys/time.h>
79 #include <sys/socket.h>
80 #include <sys/uio.h>
81 #ifdef _LIBC
82 #include <sys/poll.h>
83 #endif
85 #include <netinet/in.h>
86 #include <arpa/nameser.h>
87 #include <arpa/inet.h>
88 #include <sys/ioctl.h>
90 #include <errno.h>
91 #include <netdb.h>
92 #include <resolv.h>
93 #include <signal.h>
94 #include <stdio.h>
95 #include <stdlib.h>
96 #include <string.h>
97 #include <unistd.h>
99 #if PACKETSZ > 65536
100 #define MAXPACKET PACKETSZ
101 #else
102 #define MAXPACKET 65536
103 #endif
105 #ifndef _LIBC
106 #include <isc/eventlib.h>
107 #else
109 /* From ev_streams.c. */
111 static inline void
112 __attribute ((always_inline))
113 evConsIovec(void *buf, size_t cnt, struct iovec *vec) {
114 memset(vec, 0xf5, sizeof (*vec));
115 vec->iov_base = buf;
116 vec->iov_len = cnt;
119 /* From ev_timers.c. */
121 #define BILLION 1000000000
123 static inline void
124 evConsTime(struct timespec *res, time_t sec, long nsec) {
125 res->tv_sec = sec;
126 res->tv_nsec = nsec;
129 static inline void
130 evAddTime(struct timespec *res, const struct timespec *addend1,
131 const struct timespec *addend2) {
132 res->tv_sec = addend1->tv_sec + addend2->tv_sec;
133 res->tv_nsec = addend1->tv_nsec + addend2->tv_nsec;
134 if (res->tv_nsec >= BILLION) {
135 res->tv_sec++;
136 res->tv_nsec -= BILLION;
140 static inline void
141 evSubTime(struct timespec *res, const struct timespec *minuend,
142 const struct timespec *subtrahend) {
143 res->tv_sec = minuend->tv_sec - subtrahend->tv_sec;
144 if (minuend->tv_nsec >= subtrahend->tv_nsec)
145 res->tv_nsec = minuend->tv_nsec - subtrahend->tv_nsec;
146 else {
147 res->tv_nsec = (BILLION
148 - subtrahend->tv_nsec + minuend->tv_nsec);
149 res->tv_sec--;
153 static inline int
154 evCmpTime(struct timespec a, struct timespec b) {
155 long x = a.tv_sec - b.tv_sec;
157 if (x == 0L)
158 x = a.tv_nsec - b.tv_nsec;
159 return (x < 0L ? (-1) : x > 0L ? (1) : (0));
162 static inline void
163 evNowTime(struct timespec *res) {
164 struct timeval now;
166 if (gettimeofday(&now, NULL) < 0)
167 evConsTime(res, 0, 0);
168 else
169 TIMEVAL_TO_TIMESPEC (&now, res);
172 #endif
174 /* Options. Leave them on. */
175 /* #undef DEBUG */
176 #include "res_debug.h"
178 #define EXT(res) ((res)->_u._ext)
180 #ifndef _LIBC
181 static const int highestFD = FD_SETSIZE - 1;
182 #endif
184 /* Forward. */
186 static int send_vc(res_state, const u_char *, int,
187 u_char **, int *, int *, int, u_char **);
188 static int send_dg(res_state, const u_char *, int,
189 u_char **, int *, int *, int,
190 int *, int *, u_char **);
191 #ifdef DEBUG
192 static void Aerror(const res_state, FILE *, const char *, int,
193 struct sockaddr_in);
194 static void Perror(const res_state, FILE *, const char *, int);
195 #endif
196 #ifdef _LIBC
197 static int sock_eq(struct sockaddr_in6 *, struct sockaddr_in6 *);
198 #else
199 static int sock_eq(struct sockaddr_in *, struct sockaddr_in *);
200 #endif
201 #ifdef NEED_PSELECT
202 static int pselect(int, void *, void *, void *,
203 struct timespec *,
204 const sigset_t *);
205 #endif
207 /* Reachover. */
209 #ifdef _LIBC
210 static void convaddr4to6(struct sockaddr_in6 *sa);
211 #endif
212 void res_pquery(const res_state, const u_char *, int, FILE *);
214 /* Public. */
216 /* int
217 * res_isourserver(ina)
218 * looks up "ina" in _res.ns_addr_list[]
219 * returns:
220 * 0 : not found
221 * >0 : found
222 * author:
223 * paul vixie, 29may94
226 #ifdef _LIBC
227 res_ourserver_p(const res_state statp, const struct sockaddr_in6 *inp)
228 #else
229 res_ourserver_p(const res_state statp, const struct sockaddr_in *inp)
230 #endif
232 int ns;
234 #ifdef _LIBC
235 if (inp->sin6_family == AF_INET) {
236 struct sockaddr_in *in4p = (struct sockaddr_in *) inp;
237 in_port_t port = in4p->sin_port;
238 in_addr_t addr = in4p->sin_addr.s_addr;
240 for (ns = 0; ns < MAXNS; ns++) {
241 const struct sockaddr_in *srv =
242 (struct sockaddr_in *)EXT(statp).nsaddrs[ns];
244 if ((srv != NULL) && (srv->sin_family == AF_INET) &&
245 (srv->sin_port == port) &&
246 (srv->sin_addr.s_addr == INADDR_ANY ||
247 srv->sin_addr.s_addr == addr))
248 return (1);
250 } else if (inp->sin6_family == AF_INET6) {
251 for (ns = 0; ns < MAXNS; ns++) {
252 const struct sockaddr_in6 *srv = EXT(statp).nsaddrs[ns];
253 if ((srv != NULL) && (srv->sin6_family == AF_INET6) &&
254 (srv->sin6_port == inp->sin6_port) &&
255 !(memcmp(&srv->sin6_addr, &in6addr_any,
256 sizeof (struct in6_addr)) &&
257 memcmp(&srv->sin6_addr, &inp->sin6_addr,
258 sizeof (struct in6_addr))))
259 return (1);
262 #else
263 struct sockaddr_in ina = *inp;
264 for (ns = 0; ns < statp->nscount; ns++) {
265 const struct sockaddr_in *srv = &statp->nsaddr_list[ns];
267 if (srv->sin_family == ina.sin_family &&
268 srv->sin_port == ina.sin_port &&
269 (srv->sin_addr.s_addr == INADDR_ANY ||
270 srv->sin_addr.s_addr == ina.sin_addr.s_addr))
271 return (1);
273 #endif
274 return (0);
277 /* int
278 * res_nameinquery(name, type, class, buf, eom)
279 * look for (name,type,class) in the query section of packet (buf,eom)
280 * requires:
281 * buf + HFIXEDSZ <= eom
282 * returns:
283 * -1 : format error
284 * 0 : not found
285 * >0 : found
286 * author:
287 * paul vixie, 29may94
290 res_nameinquery(const char *name, int type, int class,
291 const u_char *buf, const u_char *eom)
293 const u_char *cp = buf + HFIXEDSZ;
294 int qdcount = ntohs(((HEADER*)buf)->qdcount);
296 while (qdcount-- > 0) {
297 char tname[MAXDNAME+1];
298 int n, ttype, tclass;
300 n = dn_expand(buf, eom, cp, tname, sizeof tname);
301 if (n < 0)
302 return (-1);
303 cp += n;
304 if (cp + 2 * INT16SZ > eom)
305 return (-1);
306 ttype = ns_get16(cp); cp += INT16SZ;
307 tclass = ns_get16(cp); cp += INT16SZ;
308 if (ttype == type && tclass == class &&
309 ns_samename(tname, name) == 1)
310 return (1);
312 return (0);
315 /* int
316 * res_queriesmatch(buf1, eom1, buf2, eom2)
317 * is there a 1:1 mapping of (name,type,class)
318 * in (buf1,eom1) and (buf2,eom2)?
319 * returns:
320 * -1 : format error
321 * 0 : not a 1:1 mapping
322 * >0 : is a 1:1 mapping
323 * author:
324 * paul vixie, 29may94
327 res_queriesmatch(const u_char *buf1, const u_char *eom1,
328 const u_char *buf2, const u_char *eom2)
330 const u_char *cp = buf1 + HFIXEDSZ;
331 int qdcount = ntohs(((HEADER*)buf1)->qdcount);
333 if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
334 return (-1);
337 * Only header section present in replies to
338 * dynamic update packets.
340 if ((((HEADER *)buf1)->opcode == ns_o_update) &&
341 (((HEADER *)buf2)->opcode == ns_o_update))
342 return (1);
344 if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
345 return (0);
346 while (qdcount-- > 0) {
347 char tname[MAXDNAME+1];
348 int n, ttype, tclass;
350 n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
351 if (n < 0)
352 return (-1);
353 cp += n;
354 if (cp + 2 * INT16SZ > eom1)
355 return (-1);
356 ttype = ns_get16(cp); cp += INT16SZ;
357 tclass = ns_get16(cp); cp += INT16SZ;
358 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
359 return (0);
361 return (1);
365 __libc_res_nsend(res_state statp, const u_char *buf, int buflen,
366 u_char *ans, int anssiz, u_char **ansp)
368 int gotsomewhere, terrno, try, v_circuit, resplen, ns, n;
370 if (statp->nscount == 0) {
371 __set_errno (ESRCH);
372 return (-1);
375 if (anssiz < HFIXEDSZ) {
376 __set_errno (EINVAL);
377 return (-1);
380 if ((statp->qhook || statp->rhook) && anssiz < MAXPACKET && ansp) {
381 u_char *buf = malloc (MAXPACKET);
382 if (buf == NULL)
383 return (-1);
384 memcpy (buf, ans, HFIXEDSZ);
385 *ansp = buf;
386 ans = buf;
387 anssiz = MAXPACKET;
390 DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY),
391 (stdout, ";; res_send()\n"), buf, buflen);
392 v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ;
393 gotsomewhere = 0;
394 terrno = ETIMEDOUT;
397 * If the ns_addr_list in the resolver context has changed, then
398 * invalidate our cached copy and the associated timing data.
400 if (EXT(statp).nsinit) {
401 int needclose = 0;
403 if (EXT(statp).nscount != statp->nscount)
404 needclose++;
405 else
406 #ifdef _LIBC
407 for (ns = 0; ns < MAXNS; ns++) {
408 unsigned int map = EXT(statp).nsmap[ns];
409 if (map < MAXNS
410 && !sock_eq((struct sockaddr_in6 *)
411 &statp->nsaddr_list[map],
412 EXT(statp).nsaddrs[ns]))
413 #else
414 for (ns = 0; ns < statp->nscount; ns++) {
415 if (!sock_eq(&statp->nsaddr_list[ns],
416 &EXT(statp).nsaddrs[ns]))
417 #endif
419 needclose++;
420 break;
423 if (needclose)
424 res_nclose(statp);
428 * Maybe initialize our private copy of the ns_addr_list.
430 if (EXT(statp).nsinit == 0) {
431 #ifdef _LIBC
432 unsigned char map[MAXNS];
434 memset (map, MAXNS, sizeof (map));
435 for (n = 0; n < MAXNS; n++) {
436 ns = EXT(statp).nsmap[n];
437 if (ns < statp->nscount)
438 map[ns] = n;
439 else if (ns < MAXNS) {
440 free(EXT(statp).nsaddrs[n]);
441 EXT(statp).nsaddrs[n] = NULL;
442 EXT(statp).nsmap[n] = MAXNS;
445 n = statp->nscount;
446 if (statp->nscount > EXT(statp).nscount)
447 for (n = EXT(statp).nscount, ns = 0;
448 n < statp->nscount; n++) {
449 while (ns < MAXNS
450 && EXT(statp).nsmap[ns] != MAXNS)
451 ns++;
452 if (ns == MAXNS)
453 break;
454 EXT(statp).nsmap[ns] = n;
455 map[n] = ns++;
457 EXT(statp).nscount = n;
458 for (ns = 0; ns < EXT(statp).nscount; ns++) {
459 n = map[ns];
460 if (EXT(statp).nsaddrs[n] == NULL)
461 EXT(statp).nsaddrs[n] =
462 malloc(sizeof (struct sockaddr_in6));
463 if (EXT(statp).nsaddrs[n] != NULL) {
464 memcpy(EXT(statp).nsaddrs[n],
465 &statp->nsaddr_list[ns],
466 sizeof (struct sockaddr_in));
467 EXT(statp).nssocks[n] = -1;
468 n++;
471 #else
472 for (ns = 0; ns < statp->nscount; ns++) {
473 EXT(statp).nsaddrs[ns] = statp->nsaddr_list[ns];
474 EXT(statp).nssocks[ns] = -1;
476 EXT(statp).nscount = ns;
477 #endif
478 EXT(statp).nsinit = 1;
482 * Some resolvers want to even out the load on their nameservers.
483 * Note that RES_BLAST overrides RES_ROTATE.
485 if ((statp->options & RES_ROTATE) != 0 &&
486 (statp->options & RES_BLAST) == 0) {
487 #ifdef _LIBC
488 struct sockaddr_in6 *ina;
489 unsigned int map;
491 n = 0;
492 while (n < MAXNS && EXT(statp).nsmap[n] == MAXNS)
493 n++;
494 if (n < MAXNS) {
495 ina = EXT(statp).nsaddrs[n];
496 map = EXT(statp).nsmap[n];
497 for (;;) {
498 ns = n + 1;
499 while (ns < MAXNS
500 && EXT(statp).nsmap[ns] == MAXNS)
501 ns++;
502 if (ns == MAXNS)
503 break;
504 EXT(statp).nsaddrs[n] = EXT(statp).nsaddrs[ns];
505 EXT(statp).nsmap[n] = EXT(statp).nsmap[ns];
506 n = ns;
508 EXT(statp).nsaddrs[n] = ina;
509 EXT(statp).nsmap[n] = map;
511 #else
512 struct sockaddr_in ina;
513 int lastns = statp->nscount - 1;
515 ina = statp->nsaddr_list[0];
516 for (ns = 0; ns < lastns; ns++)
517 statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1];
518 statp->nsaddr_list[lastns] = ina;
519 #endif
523 * Send request, RETRY times, or until successful.
525 for (try = 0; try < statp->retry; try++) {
526 #ifdef _LIBC
527 for (ns = 0; ns < MAXNS; ns++)
528 #else
529 for (ns = 0; ns < statp->nscount; ns++)
530 #endif
532 #ifdef _LIBC
533 struct sockaddr_in6 *nsap = EXT(statp).nsaddrs[ns];
535 if (nsap == NULL)
536 goto next_ns;
537 #else
538 struct sockaddr_in *nsap = &statp->nsaddr_list[ns];
539 #endif
540 same_ns:
541 if (statp->qhook) {
542 int done = 0, loops = 0;
544 do {
545 res_sendhookact act;
547 #ifdef _LIBC
548 struct sockaddr_in *nsap4;
549 nsap4 = (struct sockaddr_in *) nsap;
550 act = (*statp->qhook)(&nsap4, &buf, &buflen,
551 ans, anssiz, &resplen);
552 nsap = (struct sockaddr_in6 *) nsap4;
553 #else
554 act = (*statp->qhook)(&nsap, &buf, &buflen,
555 ans, anssiz, &resplen);
556 #endif
557 switch (act) {
558 case res_goahead:
559 done = 1;
560 break;
561 case res_nextns:
562 res_nclose(statp);
563 goto next_ns;
564 case res_done:
565 return (resplen);
566 case res_modified:
567 /* give the hook another try */
568 if (++loops < 42) /*doug adams*/
569 break;
570 /*FALLTHROUGH*/
571 case res_error:
572 /*FALLTHROUGH*/
573 default:
574 return (-1);
576 } while (!done);
579 Dprint(statp->options & RES_DEBUG,
580 (stdout, ";; Querying server (# %d) address = %s\n",
581 ns + 1, inet_ntoa(nsap->sin_addr)));
583 if (v_circuit) {
584 /* Use VC; at most one attempt per server. */
585 try = statp->retry;
586 n = send_vc(statp, buf, buflen, &ans, &anssiz, &terrno,
587 ns, ansp);
588 if (n < 0)
589 return (-1);
590 if (n == 0)
591 goto next_ns;
592 resplen = n;
593 } else {
594 /* Use datagrams. */
595 n = send_dg(statp, buf, buflen, &ans, &anssiz, &terrno,
596 ns, &v_circuit, &gotsomewhere, ansp);
597 if (n < 0)
598 return (-1);
599 if (n == 0)
600 goto next_ns;
601 if (v_circuit)
602 goto same_ns;
603 resplen = n;
606 Dprint((statp->options & RES_DEBUG) ||
607 ((statp->pfcode & RES_PRF_REPLY) &&
608 (statp->pfcode & RES_PRF_HEAD1)),
609 (stdout, ";; got answer:\n"));
611 DprintQ((statp->options & RES_DEBUG) ||
612 (statp->pfcode & RES_PRF_REPLY),
613 (stdout, ""),
614 ans, (resplen > anssiz) ? anssiz : resplen);
617 * If we have temporarily opened a virtual circuit,
618 * or if we haven't been asked to keep a socket open,
619 * close the socket.
621 if ((v_circuit && (statp->options & RES_USEVC) == 0) ||
622 (statp->options & RES_STAYOPEN) == 0) {
623 res_nclose(statp);
625 if (statp->rhook) {
626 int done = 0, loops = 0;
628 do {
629 res_sendhookact act;
631 #ifdef _LIBC
632 act = (*statp->rhook)((struct sockaddr_in *)
633 nsap, buf, buflen,
634 ans, anssiz, &resplen);
635 #else
636 act = (*statp->rhook)(nsap, buf, buflen,
637 ans, anssiz, &resplen);
638 #endif
639 switch (act) {
640 case res_goahead:
641 case res_done:
642 done = 1;
643 break;
644 case res_nextns:
645 res_nclose(statp);
646 goto next_ns;
647 case res_modified:
648 /* give the hook another try */
649 if (++loops < 42) /*doug adams*/
650 break;
651 /*FALLTHROUGH*/
652 case res_error:
653 /*FALLTHROUGH*/
654 default:
655 return (-1);
657 } while (!done);
660 return (resplen);
661 next_ns: ;
662 } /*foreach ns*/
663 } /*foreach retry*/
664 res_nclose(statp);
665 if (!v_circuit) {
666 if (!gotsomewhere)
667 __set_errno (ECONNREFUSED); /* no nameservers found */
668 else
669 __set_errno (ETIMEDOUT); /* no answer obtained */
670 } else
671 __set_errno (terrno);
672 return (-1);
676 res_nsend(res_state statp,
677 const u_char *buf, int buflen, u_char *ans, int anssiz)
679 return __libc_res_nsend(statp, buf, buflen, ans, anssiz, NULL);
682 /* Private */
684 static int
685 send_vc(res_state statp,
686 const u_char *buf, int buflen, u_char **ansp, int *anssizp,
687 int *terrno, int ns, u_char **anscp)
689 const HEADER *hp = (HEADER *) buf;
690 u_char *ans = *ansp;
691 int anssiz = *anssizp;
692 HEADER *anhp = (HEADER *) ans;
693 #ifdef _LIBC
694 struct sockaddr_in6 *nsap = EXT(statp).nsaddrs[ns];
695 #else
696 struct sockaddr_in *nsap = &statp->nsaddr_list[ns];
697 #endif
698 int truncating, connreset, resplen, n;
699 struct iovec iov[2];
700 u_short len;
701 u_char *cp;
703 connreset = 0;
704 same_ns:
705 truncating = 0;
707 /* Are we still talking to whom we want to talk to? */
708 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) {
709 #ifdef _LIBC
710 struct sockaddr_in6 peer;
711 #else
712 struct sockaddr_in peer;
713 #endif
714 int size = sizeof peer;
716 if (getpeername(statp->_vcsock,
717 (struct sockaddr *)&peer, &size) < 0 ||
718 !sock_eq(&peer, nsap)) {
719 res_nclose(statp);
720 statp->_flags &= ~RES_F_VC;
724 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) {
725 if (statp->_vcsock >= 0)
726 res_nclose(statp);
728 #ifdef _LIBC
729 statp->_vcsock = socket(nsap->sin6_family, SOCK_STREAM, 0);
730 #else
731 statp->_vcsock = socket(PF_INET, SOCK_STREAM, 0);
732 if (statp->_vcsock > highestFD) {
733 res_nclose(statp);
734 __set_errno (ENOTSOCK);
736 #endif
737 if (statp->_vcsock < 0) {
738 *terrno = errno;
739 Perror(statp, stderr, "socket(vc)", errno);
740 return (-1);
742 __set_errno (0);
743 if (connect(statp->_vcsock, (struct sockaddr *)nsap,
744 sizeof *nsap) < 0) {
745 *terrno = errno;
746 Aerror(statp, stderr, "connect/vc", errno, *nsap);
747 res_nclose(statp);
748 return (0);
750 statp->_flags |= RES_F_VC;
754 * Send length & message
756 putshort((u_short)buflen, (u_char*)&len);
757 evConsIovec(&len, INT16SZ, &iov[0]);
758 evConsIovec((void*)buf, buflen, &iov[1]);
759 if (TEMP_FAILURE_RETRY (writev(statp->_vcsock, iov, 2))
760 != (INT16SZ + buflen)) {
761 *terrno = errno;
762 Perror(statp, stderr, "write failed", errno);
763 res_nclose(statp);
764 return (0);
767 * Receive length & response
769 read_len:
770 cp = ans;
771 len = INT16SZ;
772 while ((n = TEMP_FAILURE_RETRY (read(statp->_vcsock, (char *)cp,
773 (int)len))) > 0) {
774 cp += n;
775 if ((len -= n) <= 0)
776 break;
778 if (n <= 0) {
779 *terrno = errno;
780 Perror(statp, stderr, "read failed", errno);
781 res_nclose(statp);
783 * A long running process might get its TCP
784 * connection reset if the remote server was
785 * restarted. Requery the server instead of
786 * trying a new one. When there is only one
787 * server, this means that a query might work
788 * instead of failing. We only allow one reset
789 * per query to prevent looping.
791 if (*terrno == ECONNRESET && !connreset) {
792 connreset = 1;
793 res_nclose(statp);
794 goto same_ns;
796 res_nclose(statp);
797 return (0);
799 resplen = ns_get16(ans);
800 if (resplen > anssiz) {
801 if (anscp) {
802 ans = malloc (MAXPACKET);
803 if (ans == NULL) {
804 *terrno = ENOMEM;
805 res_nclose(statp);
806 return (0);
808 anssiz = MAXPACKET;
809 *anssizp = MAXPACKET;
810 *ansp = ans;
811 *anscp = ans;
812 anhp = (HEADER *) ans;
813 len = resplen;
814 } else {
815 Dprint(statp->options & RES_DEBUG,
816 (stdout, ";; response truncated\n")
818 truncating = 1;
819 len = anssiz;
821 } else
822 len = resplen;
823 if (len < HFIXEDSZ) {
825 * Undersized message.
827 Dprint(statp->options & RES_DEBUG,
828 (stdout, ";; undersized: %d\n", len));
829 *terrno = EMSGSIZE;
830 res_nclose(statp);
831 return (0);
833 cp = ans;
834 while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (int)len)) > 0){
835 cp += n;
836 len -= n;
838 if (n <= 0) {
839 *terrno = errno;
840 Perror(statp, stderr, "read(vc)", errno);
841 res_nclose(statp);
842 return (0);
844 if (truncating) {
846 * Flush rest of answer so connection stays in synch.
848 anhp->tc = 1;
849 len = resplen - anssiz;
850 while (len != 0) {
851 char junk[PACKETSZ];
853 n = read(statp->_vcsock, junk,
854 (len > sizeof junk) ? sizeof junk : len);
855 if (n > 0)
856 len -= n;
857 else
858 break;
862 * If the calling applicating has bailed out of
863 * a previous call and failed to arrange to have
864 * the circuit closed or the server has got
865 * itself confused, then drop the packet and
866 * wait for the correct one.
868 if (hp->id != anhp->id) {
869 DprintQ((statp->options & RES_DEBUG) ||
870 (statp->pfcode & RES_PRF_REPLY),
871 (stdout, ";; old answer (unexpected):\n"),
872 ans, (resplen > anssiz) ? anssiz: resplen);
873 goto read_len;
877 * All is well, or the error is fatal. Signal that the
878 * next nameserver ought not be tried.
880 return (resplen);
883 static int
884 send_dg(res_state statp,
885 const u_char *buf, int buflen, u_char **ansp, int *anssizp,
886 int *terrno, int ns, int *v_circuit, int *gotsomewhere, u_char **anscp)
888 const HEADER *hp = (HEADER *) buf;
889 u_char *ans = *ansp;
890 int anssiz = *anssizp;
891 HEADER *anhp = (HEADER *) ans;
892 #ifdef _LIBC
893 struct sockaddr_in6 *nsap = EXT(statp).nsaddrs[ns];
894 #else
895 const struct sockaddr_in *nsap = &statp->nsaddr_list[ns];
896 #endif
897 struct timespec now, timeout, finish;
898 #ifdef _LIBC
899 struct pollfd pfd[1];
900 int ptimeout;
901 struct sockaddr_in6 from;
902 static int socket_pf = 0;
903 #else
904 fd_set dsmask;
905 struct sockaddr_in from;
906 #endif
907 int fromlen, resplen, seconds, n, s;
909 if (EXT(statp).nssocks[ns] == -1) {
910 #ifdef _LIBC
911 /* only try IPv6 if IPv6 NS and if not failed before */
912 if ((EXT(statp).nscount6 > 0) && (socket_pf != PF_INET)) {
913 EXT(statp).nssocks[ns] =
914 socket(PF_INET6, SOCK_DGRAM, 0);
915 socket_pf = EXT(statp).nssocks[ns] < 0 ? PF_INET
916 : PF_INET6;
918 if (EXT(statp).nssocks[ns] < 0)
919 EXT(statp).nssocks[ns] = socket(PF_INET, SOCK_DGRAM, 0);
920 #else
921 EXT(statp).nssocks[ns] = socket(PF_INET, SOCK_DGRAM, 0);
922 if (EXT(statp).nssocks[ns] > highestFD) {
923 res_nclose(statp);
924 __set_errno (ENOTSOCK);
926 #endif
927 if (EXT(statp).nssocks[ns] < 0) {
928 *terrno = errno;
929 Perror(statp, stderr, "socket(dg)", errno);
930 return (-1);
932 #ifndef CANNOT_CONNECT_DGRAM
933 #ifdef _LIBC
934 /* If IPv6 socket and nsap is IPv4, make it IPv4-mapped */
935 if ((socket_pf == PF_INET6) && (nsap->sin6_family == AF_INET))
936 convaddr4to6(nsap);
937 #endif
939 * On a 4.3BSD+ machine (client and server,
940 * actually), sending to a nameserver datagram
941 * port with no nameserver will cause an
942 * ICMP port unreachable message to be returned.
943 * If our datagram socket is "connected" to the
944 * server, we get an ECONNREFUSED error on the next
945 * socket operation, and select returns if the
946 * error message is received. We can thus detect
947 * the absence of a nameserver without timing out.
949 if (connect(EXT(statp).nssocks[ns], (struct sockaddr *)nsap,
950 sizeof *nsap) < 0) {
951 Aerror(statp, stderr, "connect(dg)", errno, *nsap);
952 res_nclose(statp);
953 return (0);
955 #endif /* !CANNOT_CONNECT_DGRAM */
956 Dprint(statp->options & RES_DEBUG,
957 (stdout, ";; new DG socket\n"))
959 s = EXT(statp).nssocks[ns];
960 #ifndef CANNOT_CONNECT_DGRAM
961 if (send(s, (char*)buf, buflen, 0) != buflen) {
962 Perror(statp, stderr, "send", errno);
963 res_nclose(statp);
964 return (0);
966 #else /* !CANNOT_CONNECT_DGRAM */
967 #ifdef _LIBC
968 /* If IPv6 socket and nsap is IPv4, make it IPv4-mapped */
969 if ((socket_pf == PF_INET6) && (nsap->sin6_family == AF_INET))
970 convaddr4to6(nsap);
971 #endif
972 if (sendto(s, (char*)buf, buflen, 0,
973 (struct sockaddr *)nsap, sizeof *nsap) != buflen)
975 Aerror(statp, stderr, "sendto", errno, *nsap);
976 res_nclose(statp);
977 return (0);
979 #endif /* !CANNOT_CONNECT_DGRAM */
982 * Wait for reply.
984 seconds = (statp->retrans << ns);
985 if (ns > 0)
986 seconds /= statp->nscount;
987 if (seconds <= 0)
988 seconds = 1;
989 evNowTime(&now);
990 evConsTime(&timeout, seconds, 0);
991 evAddTime(&finish, &now, &timeout);
992 wait:
993 #ifdef _LIBC
994 /* Convert struct timespec in milliseconds. */
995 ptimeout = timeout.tv_sec * 1000 + timeout.tv_nsec / 1000000;
997 pfd[0].fd = s;
998 pfd[0].events = POLLIN;
999 n = __poll (pfd, 1, ptimeout);
1000 #else
1001 FD_ZERO(&dsmask);
1002 FD_SET(s, &dsmask);
1003 n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL);
1004 #endif
1005 if (n == 0) {
1006 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n"));
1007 *gotsomewhere = 1;
1008 return (0);
1010 if (n < 0) {
1011 if (errno == EINTR) {
1012 evNowTime(&now);
1013 if (evCmpTime(finish, now) > 0) {
1014 evSubTime(&timeout, &finish, &now);
1015 goto wait;
1018 Perror(statp, stderr, "select", errno);
1019 res_nclose(statp);
1020 return (0);
1022 __set_errno (0);
1023 #ifdef _LIBC
1024 fromlen = sizeof(struct sockaddr_in6);
1025 #else
1026 fromlen = sizeof(struct sockaddr_in);
1027 #endif
1028 if (anssiz < MAXPACKET
1029 && anscp
1030 && (ioctl (s, FIONREAD, &resplen) < 0
1031 || anssiz < resplen)) {
1032 ans = malloc (MAXPACKET);
1033 if (ans == NULL)
1034 ans = *ansp;
1035 else {
1036 anssiz = MAXPACKET;
1037 *anssizp = MAXPACKET;
1038 *ansp = ans;
1039 *anscp = ans;
1040 anhp = (HEADER *) ans;
1043 resplen = recvfrom(s, (char*)ans, anssiz,0,
1044 (struct sockaddr *)&from, &fromlen);
1045 if (resplen <= 0) {
1046 Perror(statp, stderr, "recvfrom", errno);
1047 res_nclose(statp);
1048 return (0);
1050 *gotsomewhere = 1;
1051 if (resplen < HFIXEDSZ) {
1053 * Undersized message.
1055 Dprint(statp->options & RES_DEBUG,
1056 (stdout, ";; undersized: %d\n",
1057 resplen));
1058 *terrno = EMSGSIZE;
1059 res_nclose(statp);
1060 return (0);
1062 if (hp->id != anhp->id) {
1064 * response from old query, ignore it.
1065 * XXX - potential security hazard could
1066 * be detected here.
1068 DprintQ((statp->options & RES_DEBUG) ||
1069 (statp->pfcode & RES_PRF_REPLY),
1070 (stdout, ";; old answer:\n"),
1071 ans, (resplen > anssiz) ? anssiz : resplen);
1072 goto wait;
1074 if (!(statp->options & RES_INSECURE1) &&
1075 !res_ourserver_p(statp, &from)) {
1077 * response from wrong server? ignore it.
1078 * XXX - potential security hazard could
1079 * be detected here.
1081 DprintQ((statp->options & RES_DEBUG) ||
1082 (statp->pfcode & RES_PRF_REPLY),
1083 (stdout, ";; not our server:\n"),
1084 ans, (resplen > anssiz) ? anssiz : resplen);
1085 goto wait;
1087 if (!(statp->options & RES_INSECURE2) &&
1088 !res_queriesmatch(buf, buf + buflen,
1089 ans, ans + anssiz)) {
1091 * response contains wrong query? ignore it.
1092 * XXX - potential security hazard could
1093 * be detected here.
1095 DprintQ((statp->options & RES_DEBUG) ||
1096 (statp->pfcode & RES_PRF_REPLY),
1097 (stdout, ";; wrong query name:\n"),
1098 ans, (resplen > anssiz) ? anssiz : resplen);
1099 goto wait;
1101 if (anhp->rcode == SERVFAIL ||
1102 anhp->rcode == NOTIMP ||
1103 anhp->rcode == REFUSED) {
1104 DprintQ(statp->options & RES_DEBUG,
1105 (stdout, "server rejected query:\n"),
1106 ans, (resplen > anssiz) ? anssiz : resplen);
1107 res_nclose(statp);
1108 /* don't retry if called from dig */
1109 if (!statp->pfcode)
1110 return (0);
1112 if (!(statp->options & RES_IGNTC) && anhp->tc) {
1114 * To get the rest of answer,
1115 * use TCP with same server.
1117 Dprint(statp->options & RES_DEBUG,
1118 (stdout, ";; truncated answer\n"));
1119 *v_circuit = 1;
1120 res_nclose(statp);
1121 return (1);
1124 * All is well, or the error is fatal. Signal that the
1125 * next nameserver ought not be tried.
1127 return (resplen);
1130 #ifdef DEBUG
1131 static void
1132 Aerror(const res_state statp, FILE *file, const char *string, int error,
1133 struct sockaddr_in address)
1135 int save = errno;
1137 if ((statp->options & RES_DEBUG) != 0) {
1138 char tmp[sizeof "255.255.255.255"];
1140 fprintf(file, "res_send: %s ([%s].%u): %s\n",
1141 string,
1142 inet_ntop(address.sin_family, &address.sin_addr,
1143 tmp, sizeof tmp),
1144 ntohs(address.sin_port),
1145 strerror(error));
1147 __set_errno (save);
1150 static void
1151 Perror(const res_state statp, FILE *file, const char *string, int error) {
1152 int save = errno;
1154 if ((statp->options & RES_DEBUG) != 0)
1155 fprintf(file, "res_send: %s: %s\n",
1156 string, strerror(error));
1157 __set_errno (save);
1159 #endif
1161 static int
1162 #ifdef _LIBC
1163 sock_eq(struct sockaddr_in6 *a1, struct sockaddr_in6 *a2) {
1164 if (a1->sin6_family == a2->sin6_family) {
1165 if (a1->sin6_family == AF_INET)
1166 return ((((struct sockaddr_in *)a1)->sin_port ==
1167 ((struct sockaddr_in *)a2)->sin_port) &&
1168 (((struct sockaddr_in *)a1)->sin_addr.s_addr ==
1169 ((struct sockaddr_in *)a2)->sin_addr.s_addr));
1170 else
1171 return ((a1->sin6_port == a2->sin6_port) &&
1172 !memcmp(&a1->sin6_addr, &a2->sin6_addr,
1173 sizeof (struct in6_addr)));
1175 if (a1->sin6_family == AF_INET) {
1176 struct sockaddr_in6 *sap = a1;
1177 a1 = a2;
1178 a2 = sap;
1179 } /* assumes that AF_INET and AF_INET6 are the only possibilities */
1180 return ((a1->sin6_port == ((struct sockaddr_in *)a2)->sin_port) &&
1181 IN6_IS_ADDR_V4MAPPED(&a1->sin6_addr) &&
1182 (a1->sin6_addr.s6_addr32[3] ==
1183 ((struct sockaddr_in *)a2)->sin_addr.s_addr));
1185 #else
1186 sock_eq(struct sockaddr_in *a1, struct sockaddr_in *a2) {
1187 return ((a1->sin_family == a2->sin_family) &&
1188 (a1->sin_port == a2->sin_port) &&
1189 (a1->sin_addr.s_addr == a2->sin_addr.s_addr));
1191 #endif
1193 #ifdef _LIBC
1195 * Converts IPv4 family, address and port to
1196 * IPv6 family, IPv4-mapped IPv6 address and port.
1198 static void
1199 convaddr4to6(struct sockaddr_in6 *sa)
1201 struct sockaddr_in *sa4p = (struct sockaddr_in *) sa;
1202 in_port_t port = sa4p->sin_port;
1203 in_addr_t addr = sa4p->sin_addr.s_addr;
1205 sa->sin6_family = AF_INET6;
1206 sa->sin6_port = port;
1207 sa->sin6_addr.s6_addr32[0] = 0;
1208 sa->sin6_addr.s6_addr32[1] = 0;
1209 sa->sin6_addr.s6_addr32[2] = htonl(0xFFFF);
1210 sa->sin6_addr.s6_addr32[3] = addr;
1212 #endif
1214 #ifdef NEED_PSELECT
1215 /* XXX needs to move to the porting library. */
1216 static int
1217 pselect(int nfds, void *rfds, void *wfds, void *efds,
1218 struct timespec *tsp, const sigset_t *sigmask)
1220 struct timeval tv, *tvp;
1221 sigset_t sigs;
1222 int n;
1224 if (tsp) {
1225 tvp = &tv;
1226 tv = evTimeVal(*tsp);
1227 } else
1228 tvp = NULL;
1229 if (sigmask)
1230 sigprocmask(SIG_SETMASK, sigmask, &sigs);
1231 n = select(nfds, rfds, wfds, efds, tvp);
1232 if (sigmask)
1233 sigprocmask(SIG_SETMASK, &sigs, NULL);
1234 if (tsp)
1235 TIMEVAL_TO_TIMESPEC (tv, *tsp);
1236 return (n);
1238 #endif