1 /*-
2 * SPDX-License-Identifier: (ISC AND BSD-3-Clause)
3 *
4 * Portions Copyright (C) 2004-2009 Internet Systems Consortium, Inc. ("ISC")
5 * Portions Copyright (C) 1996-2003 Internet Software Consortium.
6 *
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.
10 *
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.
18 */
19
20 /*
21 * Copyright (c) 1985, 1989, 1993
22 * The Regents of the University of California. All rights reserved.
23 *
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. Neither the name of the University nor the names of its contributors
33 * may be used to endorse or promote products derived from this software
34 * without specific prior written permission.
35 *
36 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
37 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
39 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
40 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
41 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
42 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
44 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
45 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46 * SUCH DAMAGE.
47 */
48
49 /*
50 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
51 *
52 * Permission to use, copy, modify, and distribute this software for any
53 * purpose with or without fee is hereby granted, provided that the above
54 * copyright notice and this permission notice appear in all copies, and that
55 * the name of Digital Equipment Corporation not be used in advertising or
56 * publicity pertaining to distribution of the document or software without
57 * specific, written prior permission.
58 *
59 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
60 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
61 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
62 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
63 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
64 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
65 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
66 * SOFTWARE.
67 */
68
69 #if defined(LIBC_SCCS) && !defined(lint)
70 static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
71 static const char rcsid[] = "$Id: res_send.c,v 1.22 2009/01/22 23:49:23 tbox Exp $";
72 #endif /* LIBC_SCCS and not lint */
73 #include <sys/cdefs.h>
74 __FBSDID("$FreeBSD$");
75
76 /*! \file
77 * \brief
78 * Send query to name server and wait for reply.
79 */
80
81 #include "port_before.h"
82 #if !defined(USE_KQUEUE) && !defined(USE_POLL)
83 #include "fd_setsize.h"
84 #endif
85
86 #include "namespace.h"
87 #include <sys/param.h>
88 #include <sys/time.h>
89 #include <sys/socket.h>
90 #include <sys/uio.h>
91
92 #include <netinet/in.h>
93 #include <arpa/nameser.h>
94 #include <arpa/inet.h>
95
96 #include <errno.h>
97 #include <netdb.h>
98 #include <resolv.h>
99 #include <signal.h>
100 #include <stdio.h>
101 #include <stdlib.h>
102 #include <string.h>
103 #include <unistd.h>
104
105 #include <isc/eventlib.h>
106
107 #include "port_after.h"
108
109 #ifdef USE_KQUEUE
110 #include <sys/event.h>
111 #else
112 #ifdef USE_POLL
113 #ifdef HAVE_STROPTS_H
114 #include <stropts.h>
115 #endif
116 #include <poll.h>
117 #endif /* USE_POLL */
118 #endif
119
120 #include "un-namespace.h"
121
122 /* Options. Leave them on. */
123 #ifndef DEBUG
124 #define DEBUG
125 #endif
126 #include "res_debug.h"
127 #include "res_private.h"
128
129 #define EXT(res) ((res)->_u._ext)
130
131 #if !defined(USE_POLL) && !defined(USE_KQUEUE)
132 static const int highestFD = FD_SETSIZE - 1;
133 #endif
134
135 /* Forward. */
136
137 static int get_salen(const struct sockaddr *);
138 static struct sockaddr * get_nsaddr(res_state, size_t);
139 static int send_vc(res_state, const u_char *, int,
140 u_char *, int, int *, int);
141 static int send_dg(res_state,
142 #ifdef USE_KQUEUE
143 int kq,
144 #endif
145 const u_char *, int,
146 u_char *, int, int *, int, int,
147 int *, int *);
148 static void Aerror(const res_state, FILE *, const char *, int,
149 const struct sockaddr *, int);
150 static void Perror(const res_state, FILE *, const char *, int);
151 static int sock_eq(struct sockaddr *, struct sockaddr *);
152 #if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE)
153 static int pselect(int, void *, void *, void *,
154 struct timespec *,
155 const sigset_t *);
156 #endif
157 void res_pquery(const res_state, const u_char *, int, FILE *);
158
159 static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
160
161 /* Public. */
162
163 /*%
164 * looks up "ina" in _res.ns_addr_list[]
165 *
166 * returns:
167 *\li 0 : not found
168 *\li >0 : found
169 *
170 * author:
171 *\li paul vixie, 29may94
172 */
173 int
res_ourserver_p(const res_state statp,const struct sockaddr * sa)174 res_ourserver_p(const res_state statp, const struct sockaddr *sa) {
175 const struct sockaddr_in *inp, *srv;
176 const struct sockaddr_in6 *in6p, *srv6;
177 int ns;
178
179 switch (sa->sa_family) {
180 case AF_INET:
181 inp = (const struct sockaddr_in *)sa;
182 for (ns = 0; ns < statp->nscount; ns++) {
183 srv = (struct sockaddr_in *)get_nsaddr(statp, ns);
184 if (srv->sin_family == inp->sin_family &&
185 srv->sin_port == inp->sin_port &&
186 (srv->sin_addr.s_addr == INADDR_ANY ||
187 srv->sin_addr.s_addr == inp->sin_addr.s_addr))
188 return (1);
189 }
190 break;
191 case AF_INET6:
192 if (EXT(statp).ext == NULL)
193 break;
194 in6p = (const struct sockaddr_in6 *)sa;
195 for (ns = 0; ns < statp->nscount; ns++) {
196 srv6 = (struct sockaddr_in6 *)get_nsaddr(statp, ns);
197 if (srv6->sin6_family == in6p->sin6_family &&
198 srv6->sin6_port == in6p->sin6_port &&
199 #ifdef HAVE_SIN6_SCOPE_ID
200 (srv6->sin6_scope_id == 0 ||
201 srv6->sin6_scope_id == in6p->sin6_scope_id) &&
202 #endif
203 (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) ||
204 IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr)))
205 return (1);
206 }
207 break;
208 default:
209 break;
210 }
211 return (0);
212 }
213
214 /*%
215 * look for (name,type,class) in the query section of packet (buf,eom)
216 *
217 * requires:
218 *\li buf + HFIXEDSZ <= eom
219 *
220 * returns:
221 *\li -1 : format error
222 *\li 0 : not found
223 *\li >0 : found
224 *
225 * author:
226 *\li paul vixie, 29may94
227 */
228 int
res_nameinquery(const char * name,int type,int class,const u_char * buf,const u_char * eom)229 res_nameinquery(const char *name, int type, int class,
230 const u_char *buf, const u_char *eom)
231 {
232 const u_char *cp = buf + HFIXEDSZ;
233 int qdcount = ntohs(((const HEADER*)buf)->qdcount);
234
235 while (qdcount-- > 0) {
236 char tname[MAXDNAME+1];
237 int n, ttype, tclass;
238
239 n = dn_expand(buf, eom, cp, tname, sizeof tname);
240 if (n < 0)
241 return (-1);
242 cp += n;
243 if (cp + 2 * INT16SZ > eom)
244 return (-1);
245 ttype = ns_get16(cp); cp += INT16SZ;
246 tclass = ns_get16(cp); cp += INT16SZ;
247 if (ttype == type && tclass == class &&
248 ns_samename(tname, name) == 1)
249 return (1);
250 }
251 return (0);
252 }
253
254 /*%
255 * is there a 1:1 mapping of (name,type,class)
256 * in (buf1,eom1) and (buf2,eom2)?
257 *
258 * returns:
259 *\li -1 : format error
260 *\li 0 : not a 1:1 mapping
261 *\li >0 : is a 1:1 mapping
262 *
263 * author:
264 *\li paul vixie, 29may94
265 */
266 int
res_queriesmatch(const u_char * buf1,const u_char * eom1,const u_char * buf2,const u_char * eom2)267 res_queriesmatch(const u_char *buf1, const u_char *eom1,
268 const u_char *buf2, const u_char *eom2)
269 {
270 const u_char *cp = buf1 + HFIXEDSZ;
271 int qdcount = ntohs(((const HEADER*)buf1)->qdcount);
272
273 if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
274 return (-1);
275
276 /*
277 * Only header section present in replies to
278 * dynamic update packets.
279 */
280 if ((((const HEADER *)buf1)->opcode == ns_o_update) &&
281 (((const HEADER *)buf2)->opcode == ns_o_update))
282 return (1);
283
284 if (qdcount != ntohs(((const HEADER*)buf2)->qdcount))
285 return (0);
286 while (qdcount-- > 0) {
287 char tname[MAXDNAME+1];
288 int n, ttype, tclass;
289
290 n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
291 if (n < 0)
292 return (-1);
293 cp += n;
294 if (cp + 2 * INT16SZ > eom1)
295 return (-1);
296 ttype = ns_get16(cp); cp += INT16SZ;
297 tclass = ns_get16(cp); cp += INT16SZ;
298 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
299 return (0);
300 }
301 return (1);
302 }
303
304 int
res_nsend(res_state statp,const u_char * buf,int buflen,u_char * ans,int anssiz)305 res_nsend(res_state statp,
306 const u_char *buf, int buflen, u_char *ans, int anssiz)
307 {
308 int gotsomewhere, terrno, tries, v_circuit, resplen, ns, n;
309 #ifdef USE_KQUEUE
310 int kq;
311 #endif
312 char abuf[NI_MAXHOST];
313
314 /* No name servers or res_init() failure */
315 if (statp->nscount == 0 || EXT(statp).ext == NULL) {
316 errno = ESRCH;
317 return (-1);
318 }
319 if (anssiz < HFIXEDSZ) {
320 errno = EINVAL;
321 return (-1);
322 }
323 DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY),
324 (stdout, ";; res_send()\n"), buf, buflen);
325 v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ;
326 gotsomewhere = 0;
327 terrno = ETIMEDOUT;
328
329 #ifdef USE_KQUEUE
330 if ((kq = kqueue()) < 0) {
331 Perror(statp, stderr, "kqueue", errno);
332 return (-1);
333 }
334 #endif
335
336 /*
337 * If the ns_addr_list in the resolver context has changed, then
338 * invalidate our cached copy and the associated timing data.
339 */
340 if (EXT(statp).nscount != 0) {
341 int needclose = 0;
342 struct sockaddr_storage peer;
343 ISC_SOCKLEN_T peerlen;
344
345 if (EXT(statp).nscount != statp->nscount)
346 needclose++;
347 else
348 for (ns = 0; ns < statp->nscount; ns++) {
349 if (statp->nsaddr_list[ns].sin_family &&
350 !sock_eq((struct sockaddr *)&statp->nsaddr_list[ns],
351 (struct sockaddr *)&EXT(statp).ext->nsaddrs[ns])) {
352 needclose++;
353 break;
354 }
355
356 if (EXT(statp).nssocks[ns] == -1)
357 continue;
358 peerlen = sizeof(peer);
359 if (_getpeername(EXT(statp).nssocks[ns],
360 (struct sockaddr *)&peer, &peerlen) < 0) {
361 needclose++;
362 break;
363 }
364 if (!sock_eq((struct sockaddr *)&peer,
365 get_nsaddr(statp, ns))) {
366 needclose++;
367 break;
368 }
369 }
370 if (needclose) {
371 res_nclose(statp);
372 EXT(statp).nscount = 0;
373 }
374 }
375
376 /*
377 * Maybe initialize our private copy of the ns_addr_list.
378 */
379 if (EXT(statp).nscount == 0) {
380 for (ns = 0; ns < statp->nscount; ns++) {
381 EXT(statp).nstimes[ns] = RES_MAXTIME;
382 EXT(statp).nssocks[ns] = -1;
383 if (!statp->nsaddr_list[ns].sin_family)
384 continue;
385 EXT(statp).ext->nsaddrs[ns].sin =
386 statp->nsaddr_list[ns];
387 }
388 EXT(statp).nscount = statp->nscount;
389 }
390
391 /*
392 * Some resolvers want to even out the load on their nameservers.
393 * Note that RES_BLAST overrides RES_ROTATE.
394 */
395 if ((statp->options & RES_ROTATE) != 0U &&
396 (statp->options & RES_BLAST) == 0U) {
397 union res_sockaddr_union inu;
398 struct sockaddr_in ina;
399 int lastns = statp->nscount - 1;
400 int fd;
401 u_int16_t nstime;
402
403 if (EXT(statp).ext != NULL)
404 inu = EXT(statp).ext->nsaddrs[0];
405 ina = statp->nsaddr_list[0];
406 fd = EXT(statp).nssocks[0];
407 nstime = EXT(statp).nstimes[0];
408 for (ns = 0; ns < lastns; ns++) {
409 if (EXT(statp).ext != NULL)
410 EXT(statp).ext->nsaddrs[ns] =
411 EXT(statp).ext->nsaddrs[ns + 1];
412 statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1];
413 EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1];
414 EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1];
415 }
416 if (EXT(statp).ext != NULL)
417 EXT(statp).ext->nsaddrs[lastns] = inu;
418 statp->nsaddr_list[lastns] = ina;
419 EXT(statp).nssocks[lastns] = fd;
420 EXT(statp).nstimes[lastns] = nstime;
421 }
422
423 /*
424 * Send request, RETRY times, or until successful.
425 */
426 for (tries = 0; tries < statp->retry; tries++) {
427 for (ns = 0; ns < statp->nscount; ns++) {
428 struct sockaddr *nsap;
429 int nsaplen;
430 nsap = get_nsaddr(statp, ns);
431 nsaplen = get_salen(nsap);
432 statp->_flags &= ~RES_F_LASTMASK;
433 statp->_flags |= (ns << RES_F_LASTSHIFT);
434 same_ns:
435 if (statp->qhook) {
436 int done = 0, loops = 0;
437
438 do {
439 res_sendhookact act;
440
441 act = (*statp->qhook)(&nsap, &buf, &buflen,
442 ans, anssiz, &resplen);
443 switch (act) {
444 case res_goahead:
445 done = 1;
446 break;
447 case res_nextns:
448 res_nclose(statp);
449 goto next_ns;
450 case res_done:
451 #ifdef USE_KQUEUE
452 _close(kq);
453 #endif
454 return (resplen);
455 case res_modified:
456 /* give the hook another try */
457 if (++loops < 42) /*doug adams*/
458 break;
459 /*FALLTHROUGH*/
460 case res_error:
461 /*FALLTHROUGH*/
462 default:
463 goto fail;
464 }
465 } while (!done);
466 }
467
468 Dprint(((statp->options & RES_DEBUG) &&
469 getnameinfo(nsap, nsaplen, abuf, sizeof(abuf),
470 NULL, 0, niflags) == 0),
471 (stdout, ";; Querying server (# %d) address = %s\n",
472 ns + 1, abuf));
473
474
475 if (v_circuit) {
476 /* Use VC; at most one attempt per server. */
477 tries = statp->retry;
478 n = send_vc(statp, buf, buflen, ans, anssiz, &terrno,
479 ns);
480 if (n < 0)
481 goto fail;
482 if (n == 0)
483 goto next_ns;
484 resplen = n;
485 } else {
486 /* Use datagrams. */
487 n = send_dg(statp,
488 #ifdef USE_KQUEUE
489 kq,
490 #endif
491 buf, buflen, ans, anssiz, &terrno,
492 ns, tries, &v_circuit, &gotsomewhere);
493 if (n < 0)
494 goto fail;
495 if (n == 0)
496 goto next_ns;
497 if (v_circuit)
498 goto same_ns;
499 resplen = n;
500 }
501
502 Dprint((statp->options & RES_DEBUG) ||
503 ((statp->pfcode & RES_PRF_REPLY) &&
504 (statp->pfcode & RES_PRF_HEAD1)),
505 (stdout, ";; got answer:\n"));
506
507 DprintQ((statp->options & RES_DEBUG) ||
508 (statp->pfcode & RES_PRF_REPLY),
509 (stdout, "%s", ""),
510 ans, (resplen > anssiz) ? anssiz : resplen);
511
512 /*
513 * If we have temporarily opened a virtual circuit,
514 * or if we haven't been asked to keep a socket open,
515 * close the socket.
516 */
517 if ((v_circuit && (statp->options & RES_USEVC) == 0U) ||
518 (statp->options & RES_STAYOPEN) == 0U) {
519 res_nclose(statp);
520 }
521 if (statp->rhook) {
522 int done = 0, loops = 0;
523
524 do {
525 res_sendhookact act;
526
527 act = (*statp->rhook)(nsap, buf, buflen,
528 ans, anssiz, &resplen);
529 switch (act) {
530 case res_goahead:
531 case res_done:
532 done = 1;
533 break;
534 case res_nextns:
535 res_nclose(statp);
536 goto next_ns;
537 case res_modified:
538 /* give the hook another try */
539 if (++loops < 42) /*doug adams*/
540 break;
541 /*FALLTHROUGH*/
542 case res_error:
543 /*FALLTHROUGH*/
544 default:
545 goto fail;
546 }
547 } while (!done);
548
549 }
550 #ifdef USE_KQUEUE
551 _close(kq);
552 #endif
553 return (resplen);
554 next_ns: ;
555 } /*foreach ns*/
556 } /*foreach retry*/
557 res_nclose(statp);
558 #ifdef USE_KQUEUE
559 _close(kq);
560 #endif
561 if (!v_circuit) {
562 if (!gotsomewhere)
563 errno = ECONNREFUSED; /*%< no nameservers found */
564 else
565 errno = ETIMEDOUT; /*%< no answer obtained */
566 } else
567 errno = terrno;
568 return (-1);
569 fail:
570 res_nclose(statp);
571 #ifdef USE_KQUEUE
572 _close(kq);
573 #endif
574 return (-1);
575 }
576
577 /* Private */
578
579 static int
get_salen(const struct sockaddr * sa)580 get_salen(const struct sockaddr *sa)
581 {
582
583 #ifdef HAVE_SA_LEN
584 /* There are people do not set sa_len. Be forgiving to them. */
585 if (sa->sa_len)
586 return (sa->sa_len);
587 #endif
588
589 if (sa->sa_family == AF_INET)
590 return (sizeof(struct sockaddr_in));
591 else if (sa->sa_family == AF_INET6)
592 return (sizeof(struct sockaddr_in6));
593 else
594 return (0); /*%< unknown, die on connect */
595 }
596
597 /*%
598 * pick appropriate nsaddr_list for use. see res_init() for initialization.
599 */
600 static struct sockaddr *
get_nsaddr(res_state statp,size_t n)601 get_nsaddr(res_state statp, size_t n)
602 {
603
604 if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) {
605 /*
606 * - EXT(statp).ext->nsaddrs[n] holds an address that is larger
607 * than struct sockaddr, and
608 * - user code did not update statp->nsaddr_list[n].
609 */
610 return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n];
611 } else {
612 /*
613 * - user code updated statp->nsaddr_list[n], or
614 * - statp->nsaddr_list[n] has the same content as
615 * EXT(statp).ext->nsaddrs[n].
616 */
617 return (struct sockaddr *)(void *)&statp->nsaddr_list[n];
618 }
619 }
620
621 static int
send_vc(res_state statp,const u_char * buf,int buflen,u_char * ans,int anssiz,int * terrno,int ns)622 send_vc(res_state statp,
623 const u_char *buf, int buflen, u_char *ans, int anssiz,
624 int *terrno, int ns)
625 {
626 const HEADER *hp = (const HEADER *) buf;
627 HEADER *anhp = (HEADER *) ans;
628 struct sockaddr *nsap;
629 int nsaplen;
630 int truncating, connreset, resplen, n;
631 struct iovec iov[2];
632 u_short len;
633 u_char *cp;
634 void *tmp;
635 #ifdef SO_NOSIGPIPE
636 int on = 1;
637 #endif
638
639 nsap = get_nsaddr(statp, ns);
640 nsaplen = get_salen(nsap);
641
642 connreset = 0;
643 same_ns:
644 truncating = 0;
645
646 /* Are we still talking to whom we want to talk to? */
647 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) {
648 struct sockaddr_storage peer;
649 ISC_SOCKLEN_T size = sizeof peer;
650
651 if (_getpeername(statp->_vcsock,
652 (struct sockaddr *)&peer, &size) < 0 ||
653 !sock_eq((struct sockaddr *)&peer, nsap)) {
654 res_nclose(statp);
655 statp->_flags &= ~RES_F_VC;
656 }
657 }
658
659 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) {
660 if (statp->_vcsock >= 0)
661 res_nclose(statp);
662
663 statp->_vcsock = _socket(nsap->sa_family, SOCK_STREAM |
664 SOCK_CLOEXEC, 0);
665 #if !defined(USE_POLL) && !defined(USE_KQUEUE)
666 if (statp->_vcsock > highestFD) {
667 res_nclose(statp);
668 errno = ENOTSOCK;
669 }
670 #endif
671 if (statp->_vcsock < 0) {
672 switch (errno) {
673 case EPROTONOSUPPORT:
674 #ifdef EPFNOSUPPORT
675 case EPFNOSUPPORT:
676 #endif
677 case EAFNOSUPPORT:
678 Perror(statp, stderr, "socket(vc)", errno);
679 return (0);
680 default:
681 *terrno = errno;
682 Perror(statp, stderr, "socket(vc)", errno);
683 return (-1);
684 }
685 }
686 #ifdef SO_NOSIGPIPE
687 /*
688 * Disable generation of SIGPIPE when writing to a closed
689 * socket. Write should return -1 and set errno to EPIPE
690 * instead.
691 *
692 * Push on even if setsockopt(SO_NOSIGPIPE) fails.
693 */
694 (void)_setsockopt(statp->_vcsock, SOL_SOCKET, SO_NOSIGPIPE, &on,
695 sizeof(on));
696 #endif
697 errno = 0;
698 if (_connect(statp->_vcsock, nsap, nsaplen) < 0) {
699 *terrno = errno;
700 Aerror(statp, stderr, "connect/vc", errno, nsap,
701 nsaplen);
702 res_nclose(statp);
703 return (0);
704 }
705 statp->_flags |= RES_F_VC;
706 }
707
708 /*
709 * Send length & message
710 */
711 ns_put16((u_short)buflen, (u_char*)&len);
712 iov[0] = evConsIovec(&len, INT16SZ);
713 DE_CONST(buf, tmp);
714 iov[1] = evConsIovec(tmp, buflen);
715 if (_writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) {
716 *terrno = errno;
717 Perror(statp, stderr, "write failed", errno);
718 res_nclose(statp);
719 return (0);
720 }
721 /*
722 * Receive length & response
723 */
724 read_len:
725 cp = ans;
726 len = INT16SZ;
727 while ((n = _read(statp->_vcsock, (char *)cp, (int)len)) > 0) {
728 cp += n;
729 if ((len -= n) == 0)
730 break;
731 }
732 if (n <= 0) {
733 *terrno = errno;
734 Perror(statp, stderr, "read failed", errno);
735 res_nclose(statp);
736 /*
737 * A long running process might get its TCP
738 * connection reset if the remote server was
739 * restarted. Requery the server instead of
740 * trying a new one. When there is only one
741 * server, this means that a query might work
742 * instead of failing. We only allow one reset
743 * per query to prevent looping.
744 */
745 if (*terrno == ECONNRESET && !connreset) {
746 connreset = 1;
747 res_nclose(statp);
748 goto same_ns;
749 }
750 res_nclose(statp);
751 return (0);
752 }
753 resplen = ns_get16(ans);
754 if (resplen > anssiz) {
755 Dprint(statp->options & RES_DEBUG,
756 (stdout, ";; response truncated\n")
757 );
758 truncating = 1;
759 len = anssiz;
760 } else
761 len = resplen;
762 if (len < HFIXEDSZ) {
763 /*
764 * Undersized message.
765 */
766 Dprint(statp->options & RES_DEBUG,
767 (stdout, ";; undersized: %d\n", len));
768 *terrno = EMSGSIZE;
769 res_nclose(statp);
770 return (0);
771 }
772 cp = ans;
773 while (len != 0 &&
774 (n = _read(statp->_vcsock, (char *)cp, (int)len)) > 0) {
775 cp += n;
776 len -= n;
777 }
778 if (n <= 0) {
779 *terrno = errno;
780 Perror(statp, stderr, "read(vc)", errno);
781 res_nclose(statp);
782 return (0);
783 }
784 if (truncating) {
785 /*
786 * Flush rest of answer so connection stays in synch.
787 */
788 anhp->tc = 1;
789 len = resplen - anssiz;
790 while (len != 0) {
791 char junk[PACKETSZ];
792
793 n = _read(statp->_vcsock, junk,
794 (len > sizeof junk) ? sizeof junk : len);
795 if (n > 0)
796 len -= n;
797 else
798 break;
799 }
800 }
801 /*
802 * If the calling applicating has bailed out of
803 * a previous call and failed to arrange to have
804 * the circuit closed or the server has got
805 * itself confused, then drop the packet and
806 * wait for the correct one.
807 */
808 if (hp->id != anhp->id) {
809 DprintQ((statp->options & RES_DEBUG) ||
810 (statp->pfcode & RES_PRF_REPLY),
811 (stdout, ";; old answer (unexpected):\n"),
812 ans, (resplen > anssiz) ? anssiz: resplen);
813 goto read_len;
814 }
815
816 /*
817 * All is well, or the error is fatal. Signal that the
818 * next nameserver ought not be tried.
819 */
820 return (resplen);
821 }
822
823 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)824 send_dg(res_state statp,
825 #ifdef USE_KQUEUE
826 int kq,
827 #endif
828 const u_char *buf, int buflen, u_char *ans,
829 int anssiz, int *terrno, int ns, int tries, int *v_circuit,
830 int *gotsomewhere)
831 {
832 const HEADER *hp = (const HEADER *) buf;
833 HEADER *anhp = (HEADER *) 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_KQUEUE
841 struct kevent kv;
842 #else
843 #ifdef USE_POLL
844 int polltimeout;
845 struct pollfd pollfd;
846 #else
847 fd_set dsmask;
848 #endif
849 #endif
850
851 nsap = get_nsaddr(statp, ns);
852 nsaplen = get_salen(nsap);
853 if (EXT(statp).nssocks[ns] == -1) {
854 EXT(statp).nssocks[ns] = _socket(nsap->sa_family,
855 SOCK_DGRAM | SOCK_CLOEXEC, 0);
856 #if !defined(USE_POLL) && !defined(USE_KQUEUE)
857 if (EXT(statp).nssocks[ns] > highestFD) {
858 res_nclose(statp);
859 errno = ENOTSOCK;
860 }
861 #endif
862 if (EXT(statp).nssocks[ns] < 0) {
863 switch (errno) {
864 case EPROTONOSUPPORT:
865 #ifdef EPFNOSUPPORT
866 case EPFNOSUPPORT:
867 #endif
868 case EAFNOSUPPORT:
869 Perror(statp, stderr, "socket(dg)", errno);
870 return (0);
871 default:
872 *terrno = errno;
873 Perror(statp, stderr, "socket(dg)", errno);
874 return (-1);
875 }
876 }
877 #ifndef CANNOT_CONNECT_DGRAM
878 /*
879 * On a 4.3BSD+ machine (client and server,
880 * actually), sending to a nameserver datagram
881 * port with no nameserver will cause an
882 * ICMP port unreachable message to be returned.
883 * If our datagram socket is "connected" to the
884 * server, we get an ECONNREFUSED error on the next
885 * socket operation, and select returns if the
886 * error message is received. We can thus detect
887 * the absence of a nameserver without timing out.
888 *
889 * When the option "insecure1" is specified, we'd
890 * rather expect to see responses from an "unknown"
891 * address. In order to let the kernel accept such
892 * responses, do not connect the socket here.
893 * XXX: or do we need an explicit option to disable
894 * connecting?
895 */
896 if (!(statp->options & RES_INSECURE1) &&
897 _connect(EXT(statp).nssocks[ns], nsap, nsaplen) < 0) {
898 Aerror(statp, stderr, "connect(dg)", errno, nsap,
899 nsaplen);
900 res_nclose(statp);
901 return (0);
902 }
903 #endif /* !CANNOT_CONNECT_DGRAM */
904 Dprint(statp->options & RES_DEBUG,
905 (stdout, ";; new DG socket\n"))
906 }
907 s = EXT(statp).nssocks[ns];
908 #ifndef CANNOT_CONNECT_DGRAM
909 if (statp->options & RES_INSECURE1) {
910 if (_sendto(s,
911 (const char*)buf, buflen, 0, nsap, nsaplen) != buflen) {
912 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen);
913 res_nclose(statp);
914 return (0);
915 }
916 } else if (send(s, (const char*)buf, buflen, 0) != buflen) {
917 Perror(statp, stderr, "send", errno);
918 res_nclose(statp);
919 return (0);
920 }
921 #else /* !CANNOT_CONNECT_DGRAM */
922 if (_sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen)
923 {
924 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen);
925 res_nclose(statp);
926 return (0);
927 }
928 #endif /* !CANNOT_CONNECT_DGRAM */
929
930 /*
931 * Wait for reply.
932 */
933 seconds = (statp->retrans << tries);
934 if (ns > 0)
935 seconds /= statp->nscount;
936 if (seconds <= 0)
937 seconds = 1;
938 now = evNowTime();
939 timeout = evConsTime(seconds, 0);
940 finish = evAddTime(now, timeout);
941 goto nonow;
942 wait:
943 now = evNowTime();
944 nonow:
945 #ifndef USE_POLL
946 if (evCmpTime(finish, now) > 0)
947 timeout = evSubTime(finish, now);
948 else
949 timeout = evConsTime(0, 0);
950 #ifdef USE_KQUEUE
951 EV_SET(&kv, s, EVFILT_READ, EV_ADD | EV_ONESHOT, 0, 0, 0);
952 n = _kevent(kq, &kv, 1, &kv, 1, &timeout);
953 #else
954 FD_ZERO(&dsmask);
955 FD_SET(s, &dsmask);
956 n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL);
957 #endif
958 #else
959 timeout = evSubTime(finish, now);
960 if (timeout.tv_sec < 0)
961 timeout = evConsTime(0, 0);
962 polltimeout = 1000*timeout.tv_sec +
963 timeout.tv_nsec/1000000;
964 pollfd.fd = s;
965 pollfd.events = POLLRDNORM;
966 n = _poll(&pollfd, 1, polltimeout);
967 #endif /* USE_POLL */
968
969 if (n == 0) {
970 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n"));
971 *gotsomewhere = 1;
972 return (0);
973 }
974 if (n < 0) {
975 if (errno == EINTR)
976 goto wait;
977 #ifdef USE_KQUEUE
978 Perror(statp, stderr, "kevent", errno);
979 #else
980 #ifndef USE_POLL
981 Perror(statp, stderr, "select", errno);
982 #else
983 Perror(statp, stderr, "poll", errno);
984 #endif /* USE_POLL */
985 #endif
986 res_nclose(statp);
987 return (0);
988 }
989 #ifdef USE_KQUEUE
990 if (kv.ident != s)
991 goto wait;
992 #endif
993 errno = 0;
994 fromlen = sizeof(from);
995 resplen = _recvfrom(s, (char*)ans, anssiz,0,
996 (struct sockaddr *)&from, &fromlen);
997 if (resplen <= 0) {
998 Perror(statp, stderr, "recvfrom", errno);
999 res_nclose(statp);
1000 return (0);
1001 }
1002 *gotsomewhere = 1;
1003 if (resplen < HFIXEDSZ) {
1004 /*
1005 * Undersized message.
1006 */
1007 Dprint(statp->options & RES_DEBUG,
1008 (stdout, ";; undersized: %d\n",
1009 resplen));
1010 *terrno = EMSGSIZE;
1011 res_nclose(statp);
1012 return (0);
1013 }
1014 if (hp->id != anhp->id) {
1015 /*
1016 * response from old query, ignore it.
1017 * XXX - potential security hazard could
1018 * be detected here.
1019 */
1020 DprintQ((statp->options & RES_DEBUG) ||
1021 (statp->pfcode & RES_PRF_REPLY),
1022 (stdout, ";; old answer:\n"),
1023 ans, (resplen > anssiz) ? anssiz : resplen);
1024 goto wait;
1025 }
1026 if (!(statp->options & RES_INSECURE1) &&
1027 !res_ourserver_p(statp, (struct sockaddr *)&from)) {
1028 /*
1029 * response from wrong server? ignore it.
1030 * XXX - potential security hazard could
1031 * be detected here.
1032 */
1033 DprintQ((statp->options & RES_DEBUG) ||
1034 (statp->pfcode & RES_PRF_REPLY),
1035 (stdout, ";; not our server:\n"),
1036 ans, (resplen > anssiz) ? anssiz : resplen);
1037 goto wait;
1038 }
1039 #ifdef RES_USE_EDNS0
1040 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) {
1041 /*
1042 * Do not retry if the server do not understand EDNS0.
1043 * The case has to be captured here, as FORMERR packet do not
1044 * carry query section, hence res_queriesmatch() returns 0.
1045 */
1046 DprintQ(statp->options & RES_DEBUG,
1047 (stdout, "server rejected query with EDNS0:\n"),
1048 ans, (resplen > anssiz) ? anssiz : resplen);
1049 /* record the error */
1050 statp->_flags |= RES_F_EDNS0ERR;
1051 res_nclose(statp);
1052 return (0);
1053 }
1054 #endif
1055 if (!(statp->options & RES_INSECURE2) &&
1056 !res_queriesmatch(buf, buf + buflen,
1057 ans, ans + anssiz)) {
1058 /*
1059 * response contains wrong query? ignore it.
1060 * XXX - potential security hazard could
1061 * be detected here.
1062 */
1063 DprintQ((statp->options & RES_DEBUG) ||
1064 (statp->pfcode & RES_PRF_REPLY),
1065 (stdout, ";; wrong query name:\n"),
1066 ans, (resplen > anssiz) ? anssiz : resplen);
1067 goto wait;
1068 }
1069 if (anhp->rcode == SERVFAIL ||
1070 anhp->rcode == NOTIMP ||
1071 anhp->rcode == REFUSED) {
1072 DprintQ(statp->options & RES_DEBUG,
1073 (stdout, "server rejected query:\n"),
1074 ans, (resplen > anssiz) ? anssiz : resplen);
1075 res_nclose(statp);
1076 /* don't retry if called from dig */
1077 if (!statp->pfcode)
1078 return (0);
1079 }
1080 if (!(statp->options & RES_IGNTC) && anhp->tc) {
1081 /*
1082 * To get the rest of answer,
1083 * use TCP with same server.
1084 */
1085 Dprint(statp->options & RES_DEBUG,
1086 (stdout, ";; truncated answer\n"));
1087 *v_circuit = 1;
1088 res_nclose(statp);
1089 return (1);
1090 }
1091 /*
1092 * All is well, or the error is fatal. Signal that the
1093 * next nameserver ought not be tried.
1094 */
1095 return (resplen);
1096 }
1097
1098 static void
Aerror(const res_state statp,FILE * file,const char * string,int error,const struct sockaddr * address,int alen)1099 Aerror(const res_state statp, FILE *file, const char *string, int error,
1100 const struct sockaddr *address, int alen)
1101 {
1102 int save = errno;
1103 char hbuf[NI_MAXHOST];
1104 char sbuf[NI_MAXSERV];
1105
1106 if ((statp->options & RES_DEBUG) != 0U) {
1107 if (getnameinfo(address, alen, hbuf, sizeof(hbuf),
1108 sbuf, sizeof(sbuf), niflags)) {
1109 strncpy(hbuf, "?", sizeof(hbuf) - 1);
1110 hbuf[sizeof(hbuf) - 1] = '\0';
1111 strncpy(sbuf, "?", sizeof(sbuf) - 1);
1112 sbuf[sizeof(sbuf) - 1] = '\0';
1113 }
1114 fprintf(file, "res_send: %s ([%s].%s): %s\n",
1115 string, hbuf, sbuf, strerror(error));
1116 }
1117 errno = save;
1118 }
1119
1120 static void
Perror(const res_state statp,FILE * file,const char * string,int error)1121 Perror(const res_state statp, FILE *file, const char *string, int error) {
1122 int save = errno;
1123
1124 if ((statp->options & RES_DEBUG) != 0U)
1125 fprintf(file, "res_send: %s: %s\n",
1126 string, strerror(error));
1127 errno = save;
1128 }
1129
1130 static int
sock_eq(struct sockaddr * a,struct sockaddr * b)1131 sock_eq(struct sockaddr *a, struct sockaddr *b) {
1132 struct sockaddr_in *a4, *b4;
1133 struct sockaddr_in6 *a6, *b6;
1134
1135 if (a->sa_family != b->sa_family)
1136 return 0;
1137 switch (a->sa_family) {
1138 case AF_INET:
1139 a4 = (struct sockaddr_in *)a;
1140 b4 = (struct sockaddr_in *)b;
1141 return a4->sin_port == b4->sin_port &&
1142 a4->sin_addr.s_addr == b4->sin_addr.s_addr;
1143 case AF_INET6:
1144 a6 = (struct sockaddr_in6 *)a;
1145 b6 = (struct sockaddr_in6 *)b;
1146 return a6->sin6_port == b6->sin6_port &&
1147 #ifdef HAVE_SIN6_SCOPE_ID
1148 a6->sin6_scope_id == b6->sin6_scope_id &&
1149 #endif
1150 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr);
1151 default:
1152 return 0;
1153 }
1154 }
1155
1156 #if defined(NEED_PSELECT) && !defined(USE_POLL) && !defined(USE_KQUEUE)
1157 /* XXX needs to move to the porting library. */
1158 static int
pselect(int nfds,void * rfds,void * wfds,void * efds,struct timespec * tsp,const sigset_t * sigmask)1159 pselect(int nfds, void *rfds, void *wfds, void *efds,
1160 struct timespec *tsp, const sigset_t *sigmask)
1161 {
1162 struct timeval tv, *tvp;
1163 sigset_t sigs;
1164 int n;
1165
1166 if (tsp) {
1167 tvp = &tv;
1168 tv = evTimeVal(*tsp);
1169 } else
1170 tvp = NULL;
1171 if (sigmask)
1172 sigprocmask(SIG_SETMASK, sigmask, &sigs);
1173 n = select(nfds, rfds, wfds, efds, tvp);
1174 if (sigmask)
1175 sigprocmask(SIG_SETMASK, &sigs, NULL);
1176 if (tsp)
1177 *tsp = evTimeSpec(tv);
1178 return (n);
1179 }
1180 #endif
1181