1 /*
2 * Portions Copyright (C) 2004-2009 Internet Systems Consortium, Inc. ("ISC")
3 * Portions Copyright (C) 1996-2003 Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 /*
19 * Copyright (c) 1985, 1989, 1993
20 * The Regents of the University of California. All rights reserved.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the above copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 4. Neither the name of the University nor the names of its contributors
31 * may be used to endorse or promote products derived from this software
32 * without specific prior written permission.
33 *
34 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
35 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
37 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
38 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
39 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
40 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
41 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
42 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
43 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
44 * SUCH DAMAGE.
45 */
46
47 /*
48 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
49 *
50 * Permission to use, copy, modify, and distribute this software for any
51 * purpose with or without fee is hereby granted, provided that the above
52 * copyright notice and this permission notice appear in all copies, and that
53 * the name of Digital Equipment Corporation not be used in advertising or
54 * publicity pertaining to distribution of the document or software without
55 * specific, written prior permission.
56 *
57 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
58 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
59 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
60 * CORPORATION 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.
65 */
66
67 #if defined(LIBC_SCCS) && !defined(lint)
68 static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
69 static const char rcsid[] = "$Id: res_send.c,v 1.22 2009/01/22 23:49:23 tbox Exp $";
70 #endif /* LIBC_SCCS and not lint */
71 #include <sys/cdefs.h>
72 __FBSDID("$FreeBSD$");
73
74 /*! \file
75 * \brief
76 * Send query to name server and wait for reply.
77 */
78
79 #include "port_before.h"
80 #if !defined(USE_KQUEUE) && !defined(USE_POLL)
81 #include "fd_setsize.h"
82 #endif
83
84 #include "namespace.h"
85 #include <sys/param.h>
86 #include <sys/time.h>
87 #include <sys/socket.h>
88 #include <sys/uio.h>
89
90 #include <netinet/in.h>
91 #include <arpa/nameser.h>
92 #include <arpa/inet.h>
93
94 #include <errno.h>
95 #include <netdb.h>
96 #include <resolv.h>
97 #include <signal.h>
98 #include <stdio.h>
99 #include <stdlib.h>
100 #include <string.h>
101 #include <unistd.h>
102
103 #include <isc/eventlib.h>
104
105 #include "port_after.h"
106
107 #ifdef USE_KQUEUE
108 #include <sys/event.h>
109 #else
110 #ifdef USE_POLL
111 #ifdef HAVE_STROPTS_H
112 #include <stropts.h>
113 #endif
114 #include <poll.h>
115 #endif /* USE_POLL */
116 #endif
117
118 #include "un-namespace.h"
119
120 /* Options. Leave them on. */
121 #ifndef DEBUG
122 #define DEBUG
123 #endif
124 #include "res_debug.h"
125 #include "res_private.h"
126
127 #define EXT(res) ((res)->_u._ext)
128
129 #if !defined(USE_POLL) && !defined(USE_KQUEUE)
130 static const int highestFD = FD_SETSIZE - 1;
131 #endif
132
133 /* Forward. */
134
135 static int get_salen(const struct sockaddr *);
136 static struct sockaddr * get_nsaddr(res_state, size_t);
137 static int send_vc(res_state, const u_char *, int,
138 u_char *, int, int *, int);
139 static int send_dg(res_state,
140 #ifdef USE_KQUEUE
141 int kq,
142 #endif
143 const u_char *, int,
144 u_char *, int, int *, int, int,
145 int *, int *);
146 static void Aerror(const res_state, FILE *, const char *, int,
147 const struct sockaddr *, int);
148 static void Perror(const res_state, FILE *, const char *, int);
149 static int sock_eq(struct sockaddr *, struct sockaddr *);
150 #if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE)
151 static int pselect(int, void *, void *, void *,
152 struct timespec *,
153 const sigset_t *);
154 #endif
155 void res_pquery(const res_state, const u_char *, int, FILE *);
156
157 static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
158
159 /* Public. */
160
161 /*%
162 * looks up "ina" in _res.ns_addr_list[]
163 *
164 * returns:
165 *\li 0 : not found
166 *\li >0 : found
167 *
168 * author:
169 *\li paul vixie, 29may94
170 */
171 int
res_ourserver_p(const res_state statp,const struct sockaddr * sa)172 res_ourserver_p(const res_state statp, const struct sockaddr *sa) {
173 const struct sockaddr_in *inp, *srv;
174 const struct sockaddr_in6 *in6p, *srv6;
175 int ns;
176
177 switch (sa->sa_family) {
178 case AF_INET:
179 inp = (const struct sockaddr_in *)sa;
180 for (ns = 0; ns < statp->nscount; ns++) {
181 srv = (struct sockaddr_in *)get_nsaddr(statp, ns);
182 if (srv->sin_family == inp->sin_family &&
183 srv->sin_port == inp->sin_port &&
184 (srv->sin_addr.s_addr == INADDR_ANY ||
185 srv->sin_addr.s_addr == inp->sin_addr.s_addr))
186 return (1);
187 }
188 break;
189 case AF_INET6:
190 if (EXT(statp).ext == NULL)
191 break;
192 in6p = (const struct sockaddr_in6 *)sa;
193 for (ns = 0; ns < statp->nscount; ns++) {
194 srv6 = (struct sockaddr_in6 *)get_nsaddr(statp, ns);
195 if (srv6->sin6_family == in6p->sin6_family &&
196 srv6->sin6_port == in6p->sin6_port &&
197 #ifdef HAVE_SIN6_SCOPE_ID
198 (srv6->sin6_scope_id == 0 ||
199 srv6->sin6_scope_id == in6p->sin6_scope_id) &&
200 #endif
201 (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) ||
202 IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr)))
203 return (1);
204 }
205 break;
206 default:
207 break;
208 }
209 return (0);
210 }
211
212 /*%
213 * look for (name,type,class) in the query section of packet (buf,eom)
214 *
215 * requires:
216 *\li buf + HFIXEDSZ <= eom
217 *
218 * returns:
219 *\li -1 : format error
220 *\li 0 : not found
221 *\li >0 : found
222 *
223 * author:
224 *\li paul vixie, 29may94
225 */
226 int
res_nameinquery(const char * name,int type,int class,const u_char * buf,const u_char * eom)227 res_nameinquery(const char *name, int type, int class,
228 const u_char *buf, const u_char *eom)
229 {
230 const u_char *cp = buf + HFIXEDSZ;
231 int qdcount = ntohs(((const HEADER*)buf)->qdcount);
232
233 while (qdcount-- > 0) {
234 char tname[MAXDNAME+1];
235 int n, ttype, tclass;
236
237 n = dn_expand(buf, eom, cp, tname, sizeof tname);
238 if (n < 0)
239 return (-1);
240 cp += n;
241 if (cp + 2 * INT16SZ > eom)
242 return (-1);
243 ttype = ns_get16(cp); cp += INT16SZ;
244 tclass = ns_get16(cp); cp += INT16SZ;
245 if (ttype == type && tclass == class &&
246 ns_samename(tname, name) == 1)
247 return (1);
248 }
249 return (0);
250 }
251
252 /*%
253 * is there a 1:1 mapping of (name,type,class)
254 * in (buf1,eom1) and (buf2,eom2)?
255 *
256 * returns:
257 *\li -1 : format error
258 *\li 0 : not a 1:1 mapping
259 *\li >0 : is a 1:1 mapping
260 *
261 * author:
262 *\li paul vixie, 29may94
263 */
264 int
res_queriesmatch(const u_char * buf1,const u_char * eom1,const u_char * buf2,const u_char * eom2)265 res_queriesmatch(const u_char *buf1, const u_char *eom1,
266 const u_char *buf2, const u_char *eom2)
267 {
268 const u_char *cp = buf1 + HFIXEDSZ;
269 int qdcount = ntohs(((const HEADER*)buf1)->qdcount);
270
271 if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
272 return (-1);
273
274 /*
275 * Only header section present in replies to
276 * dynamic update packets.
277 */
278 if ((((const HEADER *)buf1)->opcode == ns_o_update) &&
279 (((const HEADER *)buf2)->opcode == ns_o_update))
280 return (1);
281
282 if (qdcount != ntohs(((const HEADER*)buf2)->qdcount))
283 return (0);
284 while (qdcount-- > 0) {
285 char tname[MAXDNAME+1];
286 int n, ttype, tclass;
287
288 n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
289 if (n < 0)
290 return (-1);
291 cp += n;
292 if (cp + 2 * INT16SZ > eom1)
293 return (-1);
294 ttype = ns_get16(cp); cp += INT16SZ;
295 tclass = ns_get16(cp); cp += INT16SZ;
296 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
297 return (0);
298 }
299 return (1);
300 }
301
302 int
res_nsend(res_state statp,const u_char * buf,int buflen,u_char * ans,int anssiz)303 res_nsend(res_state statp,
304 const u_char *buf, int buflen, u_char *ans, int anssiz)
305 {
306 int gotsomewhere, terrno, tries, v_circuit, resplen, ns, n;
307 #ifdef USE_KQUEUE
308 int kq;
309 #endif
310 char abuf[NI_MAXHOST];
311
312 /* No name servers or res_init() failure */
313 if (statp->nscount == 0 || EXT(statp).ext == NULL) {
314 errno = ESRCH;
315 return (-1);
316 }
317 if (anssiz < HFIXEDSZ) {
318 errno = EINVAL;
319 return (-1);
320 }
321 DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY),
322 (stdout, ";; res_send()\n"), buf, buflen);
323 v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ;
324 gotsomewhere = 0;
325 terrno = ETIMEDOUT;
326
327 #ifdef USE_KQUEUE
328 if ((kq = kqueue()) < 0) {
329 Perror(statp, stderr, "kqueue", errno);
330 return (-1);
331 }
332 #endif
333
334 /*
335 * If the ns_addr_list in the resolver context has changed, then
336 * invalidate our cached copy and the associated timing data.
337 */
338 if (EXT(statp).nscount != 0) {
339 int needclose = 0;
340 struct sockaddr_storage peer;
341 ISC_SOCKLEN_T peerlen;
342
343 if (EXT(statp).nscount != statp->nscount)
344 needclose++;
345 else
346 for (ns = 0; ns < statp->nscount; ns++) {
347 if (statp->nsaddr_list[ns].sin_family &&
348 !sock_eq((struct sockaddr *)&statp->nsaddr_list[ns],
349 (struct sockaddr *)&EXT(statp).ext->nsaddrs[ns])) {
350 needclose++;
351 break;
352 }
353
354 if (EXT(statp).nssocks[ns] == -1)
355 continue;
356 peerlen = sizeof(peer);
357 if (_getpeername(EXT(statp).nssocks[ns],
358 (struct sockaddr *)&peer, &peerlen) < 0) {
359 needclose++;
360 break;
361 }
362 if (!sock_eq((struct sockaddr *)&peer,
363 get_nsaddr(statp, ns))) {
364 needclose++;
365 break;
366 }
367 }
368 if (needclose) {
369 res_nclose(statp);
370 EXT(statp).nscount = 0;
371 }
372 }
373
374 /*
375 * Maybe initialize our private copy of the ns_addr_list.
376 */
377 if (EXT(statp).nscount == 0) {
378 for (ns = 0; ns < statp->nscount; ns++) {
379 EXT(statp).nstimes[ns] = RES_MAXTIME;
380 EXT(statp).nssocks[ns] = -1;
381 if (!statp->nsaddr_list[ns].sin_family)
382 continue;
383 EXT(statp).ext->nsaddrs[ns].sin =
384 statp->nsaddr_list[ns];
385 }
386 EXT(statp).nscount = statp->nscount;
387 }
388
389 /*
390 * Some resolvers want to even out the load on their nameservers.
391 * Note that RES_BLAST overrides RES_ROTATE.
392 */
393 if ((statp->options & RES_ROTATE) != 0U &&
394 (statp->options & RES_BLAST) == 0U) {
395 union res_sockaddr_union inu;
396 struct sockaddr_in ina;
397 int lastns = statp->nscount - 1;
398 int fd;
399 u_int16_t nstime;
400
401 if (EXT(statp).ext != NULL)
402 inu = EXT(statp).ext->nsaddrs[0];
403 ina = statp->nsaddr_list[0];
404 fd = EXT(statp).nssocks[0];
405 nstime = EXT(statp).nstimes[0];
406 for (ns = 0; ns < lastns; ns++) {
407 if (EXT(statp).ext != NULL)
408 EXT(statp).ext->nsaddrs[ns] =
409 EXT(statp).ext->nsaddrs[ns + 1];
410 statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1];
411 EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1];
412 EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1];
413 }
414 if (EXT(statp).ext != NULL)
415 EXT(statp).ext->nsaddrs[lastns] = inu;
416 statp->nsaddr_list[lastns] = ina;
417 EXT(statp).nssocks[lastns] = fd;
418 EXT(statp).nstimes[lastns] = nstime;
419 }
420
421 /*
422 * Send request, RETRY times, or until successful.
423 */
424 for (tries = 0; tries < statp->retry; tries++) {
425 for (ns = 0; ns < statp->nscount; ns++) {
426 struct sockaddr *nsap;
427 int nsaplen;
428 nsap = get_nsaddr(statp, ns);
429 nsaplen = get_salen(nsap);
430 statp->_flags &= ~RES_F_LASTMASK;
431 statp->_flags |= (ns << RES_F_LASTSHIFT);
432 same_ns:
433 if (statp->qhook) {
434 int done = 0, loops = 0;
435
436 do {
437 res_sendhookact act;
438
439 act = (*statp->qhook)(&nsap, &buf, &buflen,
440 ans, anssiz, &resplen);
441 switch (act) {
442 case res_goahead:
443 done = 1;
444 break;
445 case res_nextns:
446 res_nclose(statp);
447 goto next_ns;
448 case res_done:
449 #ifdef USE_KQUEUE
450 _close(kq);
451 #endif
452 return (resplen);
453 case res_modified:
454 /* give the hook another try */
455 if (++loops < 42) /*doug adams*/
456 break;
457 /*FALLTHROUGH*/
458 case res_error:
459 /*FALLTHROUGH*/
460 default:
461 goto fail;
462 }
463 } while (!done);
464 }
465
466 Dprint(((statp->options & RES_DEBUG) &&
467 getnameinfo(nsap, nsaplen, abuf, sizeof(abuf),
468 NULL, 0, niflags) == 0),
469 (stdout, ";; Querying server (# %d) address = %s\n",
470 ns + 1, abuf));
471
472
473 if (v_circuit) {
474 /* Use VC; at most one attempt per server. */
475 tries = statp->retry;
476 n = send_vc(statp, buf, buflen, ans, anssiz, &terrno,
477 ns);
478 if (n < 0)
479 goto fail;
480 if (n == 0)
481 goto next_ns;
482 resplen = n;
483 } else {
484 /* Use datagrams. */
485 n = send_dg(statp,
486 #ifdef USE_KQUEUE
487 kq,
488 #endif
489 buf, buflen, ans, anssiz, &terrno,
490 ns, tries, &v_circuit, &gotsomewhere);
491 if (n < 0)
492 goto fail;
493 if (n == 0)
494 goto next_ns;
495 if (v_circuit)
496 goto same_ns;
497 resplen = n;
498 }
499
500 Dprint((statp->options & RES_DEBUG) ||
501 ((statp->pfcode & RES_PRF_REPLY) &&
502 (statp->pfcode & RES_PRF_HEAD1)),
503 (stdout, ";; got answer:\n"));
504
505 DprintQ((statp->options & RES_DEBUG) ||
506 (statp->pfcode & RES_PRF_REPLY),
507 (stdout, "%s", ""),
508 ans, (resplen > anssiz) ? anssiz : resplen);
509
510 /*
511 * If we have temporarily opened a virtual circuit,
512 * or if we haven't been asked to keep a socket open,
513 * close the socket.
514 */
515 if ((v_circuit && (statp->options & RES_USEVC) == 0U) ||
516 (statp->options & RES_STAYOPEN) == 0U) {
517 res_nclose(statp);
518 }
519 if (statp->rhook) {
520 int done = 0, loops = 0;
521
522 do {
523 res_sendhookact act;
524
525 act = (*statp->rhook)(nsap, buf, buflen,
526 ans, anssiz, &resplen);
527 switch (act) {
528 case res_goahead:
529 case res_done:
530 done = 1;
531 break;
532 case res_nextns:
533 res_nclose(statp);
534 goto next_ns;
535 case res_modified:
536 /* give the hook another try */
537 if (++loops < 42) /*doug adams*/
538 break;
539 /*FALLTHROUGH*/
540 case res_error:
541 /*FALLTHROUGH*/
542 default:
543 goto fail;
544 }
545 } while (!done);
546
547 }
548 #ifdef USE_KQUEUE
549 _close(kq);
550 #endif
551 return (resplen);
552 next_ns: ;
553 } /*foreach ns*/
554 } /*foreach retry*/
555 res_nclose(statp);
556 #ifdef USE_KQUEUE
557 _close(kq);
558 #endif
559 if (!v_circuit) {
560 if (!gotsomewhere)
561 errno = ECONNREFUSED; /*%< no nameservers found */
562 else
563 errno = ETIMEDOUT; /*%< no answer obtained */
564 } else
565 errno = terrno;
566 return (-1);
567 fail:
568 res_nclose(statp);
569 #ifdef USE_KQUEUE
570 _close(kq);
571 #endif
572 return (-1);
573 }
574
575 /* Private */
576
577 static int
get_salen(const struct sockaddr * sa)578 get_salen(const struct sockaddr *sa)
579 {
580
581 #ifdef HAVE_SA_LEN
582 /* There are people do not set sa_len. Be forgiving to them. */
583 if (sa->sa_len)
584 return (sa->sa_len);
585 #endif
586
587 if (sa->sa_family == AF_INET)
588 return (sizeof(struct sockaddr_in));
589 else if (sa->sa_family == AF_INET6)
590 return (sizeof(struct sockaddr_in6));
591 else
592 return (0); /*%< unknown, die on connect */
593 }
594
595 /*%
596 * pick appropriate nsaddr_list for use. see res_init() for initialization.
597 */
598 static struct sockaddr *
get_nsaddr(res_state statp,size_t n)599 get_nsaddr(res_state statp, size_t n)
600 {
601
602 if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) {
603 /*
604 * - EXT(statp).ext->nsaddrs[n] holds an address that is larger
605 * than struct sockaddr, and
606 * - user code did not update statp->nsaddr_list[n].
607 */
608 return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n];
609 } else {
610 /*
611 * - user code updated statp->nsaddr_list[n], or
612 * - statp->nsaddr_list[n] has the same content as
613 * EXT(statp).ext->nsaddrs[n].
614 */
615 return (struct sockaddr *)(void *)&statp->nsaddr_list[n];
616 }
617 }
618
619 static int
send_vc(res_state statp,const u_char * buf,int buflen,u_char * ans,int anssiz,int * terrno,int ns)620 send_vc(res_state statp,
621 const u_char *buf, int buflen, u_char *ans, int anssiz,
622 int *terrno, int ns)
623 {
624 const HEADER *hp = (const HEADER *) buf;
625 HEADER *anhp = (HEADER *) ans;
626 struct sockaddr *nsap;
627 int nsaplen;
628 int truncating, connreset, resplen, n;
629 struct iovec iov[2];
630 u_short len;
631 u_char *cp;
632 void *tmp;
633 #ifdef SO_NOSIGPIPE
634 int on = 1;
635 #endif
636
637 nsap = get_nsaddr(statp, ns);
638 nsaplen = get_salen(nsap);
639
640 connreset = 0;
641 same_ns:
642 truncating = 0;
643
644 /* Are we still talking to whom we want to talk to? */
645 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) {
646 struct sockaddr_storage peer;
647 ISC_SOCKLEN_T size = sizeof peer;
648
649 if (_getpeername(statp->_vcsock,
650 (struct sockaddr *)&peer, &size) < 0 ||
651 !sock_eq((struct sockaddr *)&peer, nsap)) {
652 res_nclose(statp);
653 statp->_flags &= ~RES_F_VC;
654 }
655 }
656
657 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) {
658 if (statp->_vcsock >= 0)
659 res_nclose(statp);
660
661 statp->_vcsock = _socket(nsap->sa_family, SOCK_STREAM |
662 SOCK_CLOEXEC, 0);
663 #if !defined(USE_POLL) && !defined(USE_KQUEUE)
664 if (statp->_vcsock > highestFD) {
665 res_nclose(statp);
666 errno = ENOTSOCK;
667 }
668 #endif
669 if (statp->_vcsock < 0) {
670 switch (errno) {
671 case EPROTONOSUPPORT:
672 #ifdef EPFNOSUPPORT
673 case EPFNOSUPPORT:
674 #endif
675 case EAFNOSUPPORT:
676 Perror(statp, stderr, "socket(vc)", errno);
677 return (0);
678 default:
679 *terrno = errno;
680 Perror(statp, stderr, "socket(vc)", errno);
681 return (-1);
682 }
683 }
684 #ifdef SO_NOSIGPIPE
685 /*
686 * Disable generation of SIGPIPE when writing to a closed
687 * socket. Write should return -1 and set errno to EPIPE
688 * instead.
689 *
690 * Push on even if setsockopt(SO_NOSIGPIPE) fails.
691 */
692 (void)_setsockopt(statp->_vcsock, SOL_SOCKET, SO_NOSIGPIPE, &on,
693 sizeof(on));
694 #endif
695 errno = 0;
696 if (_connect(statp->_vcsock, nsap, nsaplen) < 0) {
697 *terrno = errno;
698 Aerror(statp, stderr, "connect/vc", errno, nsap,
699 nsaplen);
700 res_nclose(statp);
701 return (0);
702 }
703 statp->_flags |= RES_F_VC;
704 }
705
706 /*
707 * Send length & message
708 */
709 ns_put16((u_short)buflen, (u_char*)&len);
710 iov[0] = evConsIovec(&len, INT16SZ);
711 DE_CONST(buf, tmp);
712 iov[1] = evConsIovec(tmp, buflen);
713 if (_writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) {
714 *terrno = errno;
715 Perror(statp, stderr, "write failed", errno);
716 res_nclose(statp);
717 return (0);
718 }
719 /*
720 * Receive length & response
721 */
722 read_len:
723 cp = ans;
724 len = INT16SZ;
725 while ((n = _read(statp->_vcsock, (char *)cp, (int)len)) > 0) {
726 cp += n;
727 if ((len -= n) == 0)
728 break;
729 }
730 if (n <= 0) {
731 *terrno = errno;
732 Perror(statp, stderr, "read failed", errno);
733 res_nclose(statp);
734 /*
735 * A long running process might get its TCP
736 * connection reset if the remote server was
737 * restarted. Requery the server instead of
738 * trying a new one. When there is only one
739 * server, this means that a query might work
740 * instead of failing. We only allow one reset
741 * per query to prevent looping.
742 */
743 if (*terrno == ECONNRESET && !connreset) {
744 connreset = 1;
745 res_nclose(statp);
746 goto same_ns;
747 }
748 res_nclose(statp);
749 return (0);
750 }
751 resplen = ns_get16(ans);
752 if (resplen > anssiz) {
753 Dprint(statp->options & RES_DEBUG,
754 (stdout, ";; response truncated\n")
755 );
756 truncating = 1;
757 len = anssiz;
758 } else
759 len = resplen;
760 if (len < HFIXEDSZ) {
761 /*
762 * Undersized message.
763 */
764 Dprint(statp->options & RES_DEBUG,
765 (stdout, ";; undersized: %d\n", len));
766 *terrno = EMSGSIZE;
767 res_nclose(statp);
768 return (0);
769 }
770 cp = ans;
771 while (len != 0 &&
772 (n = _read(statp->_vcsock, (char *)cp, (int)len)) > 0) {
773 cp += n;
774 len -= n;
775 }
776 if (n <= 0) {
777 *terrno = errno;
778 Perror(statp, stderr, "read(vc)", errno);
779 res_nclose(statp);
780 return (0);
781 }
782 if (truncating) {
783 /*
784 * Flush rest of answer so connection stays in synch.
785 */
786 anhp->tc = 1;
787 len = resplen - anssiz;
788 while (len != 0) {
789 char junk[PACKETSZ];
790
791 n = _read(statp->_vcsock, junk,
792 (len > sizeof junk) ? sizeof junk : len);
793 if (n > 0)
794 len -= n;
795 else
796 break;
797 }
798 }
799 /*
800 * If the calling applicating has bailed out of
801 * a previous call and failed to arrange to have
802 * the circuit closed or the server has got
803 * itself confused, then drop the packet and
804 * wait for the correct one.
805 */
806 if (hp->id != anhp->id) {
807 DprintQ((statp->options & RES_DEBUG) ||
808 (statp->pfcode & RES_PRF_REPLY),
809 (stdout, ";; old answer (unexpected):\n"),
810 ans, (resplen > anssiz) ? anssiz: resplen);
811 goto read_len;
812 }
813
814 /*
815 * All is well, or the error is fatal. Signal that the
816 * next nameserver ought not be tried.
817 */
818 return (resplen);
819 }
820
821 static int
send_dg(res_state statp,int kq,const u_char * buf,int buflen,u_char * ans,int anssiz,int * terrno,int ns,int tries,int * v_circuit,int * gotsomewhere)822 send_dg(res_state statp,
823 #ifdef USE_KQUEUE
824 int kq,
825 #endif
826 const u_char *buf, int buflen, u_char *ans,
827 int anssiz, int *terrno, int ns, int tries, int *v_circuit,
828 int *gotsomewhere)
829 {
830 const HEADER *hp = (const HEADER *) buf;
831 HEADER *anhp = (HEADER *) ans;
832 const struct sockaddr *nsap;
833 int nsaplen;
834 struct timespec now, timeout, finish;
835 struct sockaddr_storage from;
836 ISC_SOCKLEN_T fromlen;
837 int resplen, seconds, n, s;
838 #ifdef USE_KQUEUE
839 struct kevent kv;
840 #else
841 #ifdef USE_POLL
842 int polltimeout;
843 struct pollfd pollfd;
844 #else
845 fd_set dsmask;
846 #endif
847 #endif
848
849 nsap = get_nsaddr(statp, ns);
850 nsaplen = get_salen(nsap);
851 if (EXT(statp).nssocks[ns] == -1) {
852 EXT(statp).nssocks[ns] = _socket(nsap->sa_family,
853 SOCK_DGRAM | SOCK_CLOEXEC, 0);
854 #if !defined(USE_POLL) && !defined(USE_KQUEUE)
855 if (EXT(statp).nssocks[ns] > highestFD) {
856 res_nclose(statp);
857 errno = ENOTSOCK;
858 }
859 #endif
860 if (EXT(statp).nssocks[ns] < 0) {
861 switch (errno) {
862 case EPROTONOSUPPORT:
863 #ifdef EPFNOSUPPORT
864 case EPFNOSUPPORT:
865 #endif
866 case EAFNOSUPPORT:
867 Perror(statp, stderr, "socket(dg)", errno);
868 return (0);
869 default:
870 *terrno = errno;
871 Perror(statp, stderr, "socket(dg)", errno);
872 return (-1);
873 }
874 }
875 #ifndef CANNOT_CONNECT_DGRAM
876 /*
877 * On a 4.3BSD+ machine (client and server,
878 * actually), sending to a nameserver datagram
879 * port with no nameserver will cause an
880 * ICMP port unreachable message to be returned.
881 * If our datagram socket is "connected" to the
882 * server, we get an ECONNREFUSED error on the next
883 * socket operation, and select returns if the
884 * error message is received. We can thus detect
885 * the absence of a nameserver without timing out.
886 *
887 * When the option "insecure1" is specified, we'd
888 * rather expect to see responses from an "unknown"
889 * address. In order to let the kernel accept such
890 * responses, do not connect the socket here.
891 * XXX: or do we need an explicit option to disable
892 * connecting?
893 */
894 if (!(statp->options & RES_INSECURE1) &&
895 _connect(EXT(statp).nssocks[ns], nsap, nsaplen) < 0) {
896 Aerror(statp, stderr, "connect(dg)", errno, nsap,
897 nsaplen);
898 res_nclose(statp);
899 return (0);
900 }
901 #endif /* !CANNOT_CONNECT_DGRAM */
902 Dprint(statp->options & RES_DEBUG,
903 (stdout, ";; new DG socket\n"))
904 }
905 s = EXT(statp).nssocks[ns];
906 #ifndef CANNOT_CONNECT_DGRAM
907 if (statp->options & RES_INSECURE1) {
908 if (_sendto(s,
909 (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) {
910 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen);
911 res_nclose(statp);
912 return (0);
913 }
914 } else if (send(s, (const char*)buf, buflen, 0) != buflen) {
915 Perror(statp, stderr, "send", errno);
916 res_nclose(statp);
917 return (0);
918 }
919 #else /* !CANNOT_CONNECT_DGRAM */
920 if (_sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen)
921 {
922 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen);
923 res_nclose(statp);
924 return (0);
925 }
926 #endif /* !CANNOT_CONNECT_DGRAM */
927
928 /*
929 * Wait for reply.
930 */
931 seconds = (statp->retrans << tries);
932 if (ns > 0)
933 seconds /= statp->nscount;
934 if (seconds <= 0)
935 seconds = 1;
936 now = evNowTime();
937 timeout = evConsTime(seconds, 0);
938 finish = evAddTime(now, timeout);
939 goto nonow;
940 wait:
941 now = evNowTime();
942 nonow:
943 #ifndef USE_POLL
944 if (evCmpTime(finish, now) > 0)
945 timeout = evSubTime(finish, now);
946 else
947 timeout = evConsTime(0, 0);
948 #ifdef USE_KQUEUE
949 EV_SET(&kv, s, EVFILT_READ, EV_ADD | EV_ONESHOT, 0, 0, 0);
950 n = _kevent(kq, &kv, 1, &kv, 1, &timeout);
951 #else
952 FD_ZERO(&dsmask);
953 FD_SET(s, &dsmask);
954 n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL);
955 #endif
956 #else
957 timeout = evSubTime(finish, now);
958 if (timeout.tv_sec < 0)
959 timeout = evConsTime(0, 0);
960 polltimeout = 1000*timeout.tv_sec +
961 timeout.tv_nsec/1000000;
962 pollfd.fd = s;
963 pollfd.events = POLLRDNORM;
964 n = _poll(&pollfd, 1, polltimeout);
965 #endif /* USE_POLL */
966
967 if (n == 0) {
968 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n"));
969 *gotsomewhere = 1;
970 return (0);
971 }
972 if (n < 0) {
973 if (errno == EINTR)
974 goto wait;
975 #ifdef USE_KQUEUE
976 Perror(statp, stderr, "kevent", errno);
977 #else
978 #ifndef USE_POLL
979 Perror(statp, stderr, "select", errno);
980 #else
981 Perror(statp, stderr, "poll", errno);
982 #endif /* USE_POLL */
983 #endif
984 res_nclose(statp);
985 return (0);
986 }
987 #ifdef USE_KQUEUE
988 if (kv.ident != s)
989 goto wait;
990 #endif
991 errno = 0;
992 fromlen = sizeof(from);
993 resplen = _recvfrom(s, (char*)ans, anssiz,0,
994 (struct sockaddr *)&from, &fromlen);
995 if (resplen <= 0) {
996 Perror(statp, stderr, "recvfrom", errno);
997 res_nclose(statp);
998 return (0);
999 }
1000 *gotsomewhere = 1;
1001 if (resplen < HFIXEDSZ) {
1002 /*
1003 * Undersized message.
1004 */
1005 Dprint(statp->options & RES_DEBUG,
1006 (stdout, ";; undersized: %d\n",
1007 resplen));
1008 *terrno = EMSGSIZE;
1009 res_nclose(statp);
1010 return (0);
1011 }
1012 if (hp->id != anhp->id) {
1013 /*
1014 * response from old query, ignore it.
1015 * XXX - potential security hazard could
1016 * be detected here.
1017 */
1018 DprintQ((statp->options & RES_DEBUG) ||
1019 (statp->pfcode & RES_PRF_REPLY),
1020 (stdout, ";; old answer:\n"),
1021 ans, (resplen > anssiz) ? anssiz : resplen);
1022 goto wait;
1023 }
1024 if (!(statp->options & RES_INSECURE1) &&
1025 !res_ourserver_p(statp, (struct sockaddr *)&from)) {
1026 /*
1027 * response from wrong server? ignore it.
1028 * XXX - potential security hazard could
1029 * be detected here.
1030 */
1031 DprintQ((statp->options & RES_DEBUG) ||
1032 (statp->pfcode & RES_PRF_REPLY),
1033 (stdout, ";; not our server:\n"),
1034 ans, (resplen > anssiz) ? anssiz : resplen);
1035 goto wait;
1036 }
1037 #ifdef RES_USE_EDNS0
1038 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) {
1039 /*
1040 * Do not retry if the server do not understand EDNS0.
1041 * The case has to be captured here, as FORMERR packet do not
1042 * carry query section, hence res_queriesmatch() returns 0.
1043 */
1044 DprintQ(statp->options & RES_DEBUG,
1045 (stdout, "server rejected query with EDNS0:\n"),
1046 ans, (resplen > anssiz) ? anssiz : resplen);
1047 /* record the error */
1048 statp->_flags |= RES_F_EDNS0ERR;
1049 res_nclose(statp);
1050 return (0);
1051 }
1052 #endif
1053 if (!(statp->options & RES_INSECURE2) &&
1054 !res_queriesmatch(buf, buf + buflen,
1055 ans, ans + anssiz)) {
1056 /*
1057 * response contains wrong query? ignore it.
1058 * XXX - potential security hazard could
1059 * be detected here.
1060 */
1061 DprintQ((statp->options & RES_DEBUG) ||
1062 (statp->pfcode & RES_PRF_REPLY),
1063 (stdout, ";; wrong query name:\n"),
1064 ans, (resplen > anssiz) ? anssiz : resplen);
1065 goto wait;
1066 }
1067 if (anhp->rcode == SERVFAIL ||
1068 anhp->rcode == NOTIMP ||
1069 anhp->rcode == REFUSED) {
1070 DprintQ(statp->options & RES_DEBUG,
1071 (stdout, "server rejected query:\n"),
1072 ans, (resplen > anssiz) ? anssiz : resplen);
1073 res_nclose(statp);
1074 /* don't retry if called from dig */
1075 if (!statp->pfcode)
1076 return (0);
1077 }
1078 if (!(statp->options & RES_IGNTC) && anhp->tc) {
1079 /*
1080 * To get the rest of answer,
1081 * use TCP with same server.
1082 */
1083 Dprint(statp->options & RES_DEBUG,
1084 (stdout, ";; truncated answer\n"));
1085 *v_circuit = 1;
1086 res_nclose(statp);
1087 return (1);
1088 }
1089 /*
1090 * All is well, or the error is fatal. Signal that the
1091 * next nameserver ought not be tried.
1092 */
1093 return (resplen);
1094 }
1095
1096 static void
Aerror(const res_state statp,FILE * file,const char * string,int error,const struct sockaddr * address,int alen)1097 Aerror(const res_state statp, FILE *file, const char *string, int error,
1098 const struct sockaddr *address, int alen)
1099 {
1100 int save = errno;
1101 char hbuf[NI_MAXHOST];
1102 char sbuf[NI_MAXSERV];
1103
1104 if ((statp->options & RES_DEBUG) != 0U) {
1105 if (getnameinfo(address, alen, hbuf, sizeof(hbuf),
1106 sbuf, sizeof(sbuf), niflags)) {
1107 strncpy(hbuf, "?", sizeof(hbuf) - 1);
1108 hbuf[sizeof(hbuf) - 1] = '\0';
1109 strncpy(sbuf, "?", sizeof(sbuf) - 1);
1110 sbuf[sizeof(sbuf) - 1] = '\0';
1111 }
1112 fprintf(file, "res_send: %s ([%s].%s): %s\n",
1113 string, hbuf, sbuf, strerror(error));
1114 }
1115 errno = save;
1116 }
1117
1118 static void
Perror(const res_state statp,FILE * file,const char * string,int error)1119 Perror(const res_state statp, FILE *file, const char *string, int error) {
1120 int save = errno;
1121
1122 if ((statp->options & RES_DEBUG) != 0U)
1123 fprintf(file, "res_send: %s: %s\n",
1124 string, strerror(error));
1125 errno = save;
1126 }
1127
1128 static int
sock_eq(struct sockaddr * a,struct sockaddr * b)1129 sock_eq(struct sockaddr *a, struct sockaddr *b) {
1130 struct sockaddr_in *a4, *b4;
1131 struct sockaddr_in6 *a6, *b6;
1132
1133 if (a->sa_family != b->sa_family)
1134 return 0;
1135 switch (a->sa_family) {
1136 case AF_INET:
1137 a4 = (struct sockaddr_in *)a;
1138 b4 = (struct sockaddr_in *)b;
1139 return a4->sin_port == b4->sin_port &&
1140 a4->sin_addr.s_addr == b4->sin_addr.s_addr;
1141 case AF_INET6:
1142 a6 = (struct sockaddr_in6 *)a;
1143 b6 = (struct sockaddr_in6 *)b;
1144 return a6->sin6_port == b6->sin6_port &&
1145 #ifdef HAVE_SIN6_SCOPE_ID
1146 a6->sin6_scope_id == b6->sin6_scope_id &&
1147 #endif
1148 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr);
1149 default:
1150 return 0;
1151 }
1152 }
1153
1154 #if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE)
1155 /* XXX needs to move to the porting library. */
1156 static int
pselect(int nfds,void * rfds,void * wfds,void * efds,struct timespec * tsp,const sigset_t * sigmask)1157 pselect(int nfds, void *rfds, void *wfds, void *efds,
1158 struct timespec *tsp, const sigset_t *sigmask)
1159 {
1160 struct timeval tv, *tvp;
1161 sigset_t sigs;
1162 int n;
1163
1164 if (tsp) {
1165 tvp = &tv;
1166 tv = evTimeVal(*tsp);
1167 } else
1168 tvp = NULL;
1169 if (sigmask)
1170 sigprocmask(SIG_SETMASK, sigmask, &sigs);
1171 n = select(nfds, rfds, wfds, efds, tvp);
1172 if (sigmask)
1173 sigprocmask(SIG_SETMASK, &sigs, NULL);
1174 if (tsp)
1175 *tsp = evTimeSpec(tv);
1176 return (n);
1177 }
1178 #endif
1179