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