1 /* $NetBSD: res_send.c,v 1.1.1.2 2012/09/09 16:08:10 christos Exp $ */
2
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. All advertising materials mentioning features or use of this software
33 * must display the following acknowledgement:
34 * This product includes software developed by the University of
35 * California, Berkeley and its contributors.
36 * 4. Neither the name of the University nor the names of its contributors
37 * may be used to endorse or promote products derived from this software
38 * without specific prior written permission.
39 *
40 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 */
52
53 /*
54 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
55 *
56 * Permission to use, copy, modify, and distribute this software for any
57 * purpose with or without fee is hereby granted, provided that the above
58 * copyright notice and this permission notice appear in all copies, and that
59 * the name of Digital Equipment Corporation not be used in advertising or
60 * publicity pertaining to distribution of the document or software without
61 * specific, written prior permission.
62 *
63 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
64 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
65 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
66 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
67 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
68 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
69 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
70 * SOFTWARE.
71 */
72
73 #if defined(LIBC_SCCS) && !defined(lint)
74 static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
75 static const char rcsid[] = "Id: res_send.c,v 1.22 2009/01/22 23:49:23 tbox Exp ";
76 #endif /* LIBC_SCCS and not lint */
77
78 /*! \file
79 * \brief
80 * Send query to name server and wait for reply.
81 */
82
83 #include "port_before.h"
84 #include "fd_setsize.h"
85
86 #include <sys/types.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_POLL
110 #ifdef HAVE_STROPTS_H
111 #include <stropts.h>
112 #endif
113 #include <poll.h>
114 #endif /* USE_POLL */
115
116 /* Options. Leave them on. */
117 #define DEBUG
118 #include "res_debug.h"
119 #include "res_private.h"
120
121 #define EXT(res) ((res)->_u._ext)
122
123 #ifndef USE_POLL
124 static const int highestFD = FD_SETSIZE - 1;
125 #else
126 static int highestFD = 0;
127 #endif
128
129 /* Forward. */
130
131 static int get_salen __P((const struct sockaddr *));
132 static struct sockaddr * get_nsaddr __P((res_state, size_t));
133 static int send_vc(res_state, const u_char *, int,
134 u_char *, int, int *, int);
135 static int send_dg(res_state, const u_char *, int,
136 u_char *, int, int *, int, int,
137 int *, int *);
138 static void Aerror(const res_state, FILE *, const char *, int,
139 const struct sockaddr *, int);
140 static void Perror(const res_state, FILE *, const char *, int);
141 static int sock_eq(struct sockaddr *, struct sockaddr *);
142 #if defined(NEED_PSELECT) && !defined(USE_POLL)
143 static int pselect(int, void *, void *, void *,
144 struct timespec *,
145 const sigset_t *);
146 #endif
147 void res_pquery(const res_state, const u_char *, int, FILE *);
148
149 static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
150
151 /* Public. */
152
153 /*%
154 * looks up "ina" in _res.ns_addr_list[]
155 *
156 * returns:
157 *\li 0 : not found
158 *\li >0 : found
159 *
160 * author:
161 *\li paul vixie, 29may94
162 */
163 int
res_ourserver_p(const res_state statp,const struct sockaddr * sa)164 res_ourserver_p(const res_state statp, const struct sockaddr *sa) {
165 const struct sockaddr_in *inp, *srv;
166 const struct sockaddr_in6 *in6p, *srv6;
167 int ns;
168
169 switch (sa->sa_family) {
170 case AF_INET:
171 inp = (const struct sockaddr_in *)sa;
172 for (ns = 0; ns < statp->nscount; ns++) {
173 srv = (struct sockaddr_in *)get_nsaddr(statp, ns);
174 if (srv->sin_family == inp->sin_family &&
175 srv->sin_port == inp->sin_port &&
176 (srv->sin_addr.s_addr == INADDR_ANY ||
177 srv->sin_addr.s_addr == inp->sin_addr.s_addr))
178 return (1);
179 }
180 break;
181 case AF_INET6:
182 if (EXT(statp).ext == NULL)
183 break;
184 in6p = (const struct sockaddr_in6 *)sa;
185 for (ns = 0; ns < statp->nscount; ns++) {
186 srv6 = (struct sockaddr_in6 *)get_nsaddr(statp, ns);
187 if (srv6->sin6_family == in6p->sin6_family &&
188 srv6->sin6_port == in6p->sin6_port &&
189 #ifdef HAVE_SIN6_SCOPE_ID
190 (srv6->sin6_scope_id == 0 ||
191 srv6->sin6_scope_id == in6p->sin6_scope_id) &&
192 #endif
193 (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) ||
194 IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr)))
195 return (1);
196 }
197 break;
198 default:
199 break;
200 }
201 return (0);
202 }
203
204 /*%
205 * look for (name,type,class) in the query section of packet (buf,eom)
206 *
207 * requires:
208 *\li buf + HFIXEDSZ <= eom
209 *
210 * returns:
211 *\li -1 : format error
212 *\li 0 : not found
213 *\li >0 : found
214 *
215 * author:
216 *\li paul vixie, 29may94
217 */
218 int
res_nameinquery(const char * name,int type,int class,const u_char * buf,const u_char * eom)219 res_nameinquery(const char *name, int type, int class,
220 const u_char *buf, const u_char *eom)
221 {
222 const u_char *cp = buf + HFIXEDSZ;
223 int qdcount = ntohs(((const HEADER*)buf)->qdcount);
224
225 while (qdcount-- > 0) {
226 char tname[MAXDNAME+1];
227 int n, ttype, tclass;
228
229 n = dn_expand(buf, eom, cp, tname, sizeof tname);
230 if (n < 0)
231 return (-1);
232 cp += n;
233 if (cp + 2 * INT16SZ > eom)
234 return (-1);
235 ttype = ns_get16(cp); cp += INT16SZ;
236 tclass = ns_get16(cp); cp += INT16SZ;
237 if (ttype == type && tclass == class &&
238 ns_samename(tname, name) == 1)
239 return (1);
240 }
241 return (0);
242 }
243
244 /*%
245 * is there a 1:1 mapping of (name,type,class)
246 * in (buf1,eom1) and (buf2,eom2)?
247 *
248 * returns:
249 *\li -1 : format error
250 *\li 0 : not a 1:1 mapping
251 *\li >0 : is a 1:1 mapping
252 *
253 * author:
254 *\li paul vixie, 29may94
255 */
256 int
res_queriesmatch(const u_char * buf1,const u_char * eom1,const u_char * buf2,const u_char * eom2)257 res_queriesmatch(const u_char *buf1, const u_char *eom1,
258 const u_char *buf2, const u_char *eom2)
259 {
260 const u_char *cp = buf1 + HFIXEDSZ;
261 int qdcount = ntohs(((const HEADER*)buf1)->qdcount);
262
263 if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
264 return (-1);
265
266 /*
267 * Only header section present in replies to
268 * dynamic update packets.
269 */
270 if ((((const HEADER *)buf1)->opcode == ns_o_update) &&
271 (((const HEADER *)buf2)->opcode == ns_o_update))
272 return (1);
273
274 if (qdcount != ntohs(((const HEADER*)buf2)->qdcount))
275 return (0);
276 while (qdcount-- > 0) {
277 char tname[MAXDNAME+1];
278 int n, ttype, tclass;
279
280 n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
281 if (n < 0)
282 return (-1);
283 cp += n;
284 if (cp + 2 * INT16SZ > eom1)
285 return (-1);
286 ttype = ns_get16(cp); cp += INT16SZ;
287 tclass = ns_get16(cp); cp += INT16SZ;
288 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
289 return (0);
290 }
291 return (1);
292 }
293
294 int
res_nsend(res_state statp,const u_char * buf,int buflen,u_char * ans,int anssiz)295 res_nsend(res_state statp,
296 const u_char *buf, int buflen, u_char *ans, int anssiz)
297 {
298 int gotsomewhere, terrno, tries, v_circuit, resplen, ns, n;
299 char abuf[NI_MAXHOST];
300
301 #ifdef USE_POLL
302 highestFD = sysconf(_SC_OPEN_MAX) - 1;
303 #endif
304
305 /* No name servers or res_init() failure */
306 if (statp->nscount == 0 || EXT(statp).ext == NULL) {
307 errno = ESRCH;
308 return (-1);
309 }
310 if (anssiz < HFIXEDSZ) {
311 errno = EINVAL;
312 return (-1);
313 }
314 DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY),
315 (stdout, ";; res_send()\n"), buf, buflen);
316 v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ;
317 gotsomewhere = 0;
318 terrno = ETIMEDOUT;
319
320 /*
321 * If the ns_addr_list in the resolver context has changed, then
322 * invalidate our cached copy and the associated timing data.
323 */
324 if (EXT(statp).nscount != 0) {
325 int needclose = 0;
326 struct sockaddr_storage peer;
327 ISC_SOCKLEN_T peerlen;
328
329 if (EXT(statp).nscount != statp->nscount)
330 needclose++;
331 else
332 for (ns = 0; ns < statp->nscount; ns++) {
333 if (statp->nsaddr_list[ns].sin_family &&
334 !sock_eq((struct sockaddr *)&statp->nsaddr_list[ns],
335 (struct sockaddr *)&EXT(statp).ext->nsaddrs[ns])) {
336 needclose++;
337 break;
338 }
339
340 if (EXT(statp).nssocks[ns] == -1)
341 continue;
342 peerlen = sizeof(peer);
343 if (getpeername(EXT(statp).nssocks[ns],
344 (struct sockaddr *)&peer, &peerlen) < 0) {
345 needclose++;
346 break;
347 }
348 if (!sock_eq((struct sockaddr *)&peer,
349 get_nsaddr(statp, ns))) {
350 needclose++;
351 break;
352 }
353 }
354 if (needclose) {
355 res_nclose(statp);
356 EXT(statp).nscount = 0;
357 }
358 }
359
360 /*
361 * Maybe initialize our private copy of the ns_addr_list.
362 */
363 if (EXT(statp).nscount == 0) {
364 for (ns = 0; ns < statp->nscount; ns++) {
365 EXT(statp).nstimes[ns] = RES_MAXTIME;
366 EXT(statp).nssocks[ns] = -1;
367 if (!statp->nsaddr_list[ns].sin_family)
368 continue;
369 EXT(statp).ext->nsaddrs[ns].sin =
370 statp->nsaddr_list[ns];
371 }
372 EXT(statp).nscount = statp->nscount;
373 }
374
375 /*
376 * Some resolvers want to even out the load on their nameservers.
377 * Note that RES_BLAST overrides RES_ROTATE.
378 */
379 if ((statp->options & RES_ROTATE) != 0U &&
380 (statp->options & RES_BLAST) == 0U) {
381 union res_sockaddr_union inu;
382 struct sockaddr_in ina;
383 int lastns = statp->nscount - 1;
384 int fd;
385 u_int16_t nstime;
386
387 if (EXT(statp).ext != NULL)
388 inu = EXT(statp).ext->nsaddrs[0];
389 ina = statp->nsaddr_list[0];
390 fd = EXT(statp).nssocks[0];
391 nstime = EXT(statp).nstimes[0];
392 for (ns = 0; ns < lastns; ns++) {
393 if (EXT(statp).ext != NULL)
394 EXT(statp).ext->nsaddrs[ns] =
395 EXT(statp).ext->nsaddrs[ns + 1];
396 statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1];
397 EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1];
398 EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1];
399 }
400 if (EXT(statp).ext != NULL)
401 EXT(statp).ext->nsaddrs[lastns] = inu;
402 statp->nsaddr_list[lastns] = ina;
403 EXT(statp).nssocks[lastns] = fd;
404 EXT(statp).nstimes[lastns] = nstime;
405 }
406
407 /*
408 * Send request, RETRY times, or until successful.
409 */
410 for (tries = 0; tries < statp->retry; tries++) {
411 for (ns = 0; ns < statp->nscount; ns++) {
412 struct sockaddr *nsap;
413 int nsaplen;
414 nsap = get_nsaddr(statp, ns);
415 nsaplen = get_salen(nsap);
416 statp->_flags &= ~RES_F_LASTMASK;
417 statp->_flags |= (ns << RES_F_LASTSHIFT);
418 same_ns:
419 if (statp->qhook) {
420 int done = 0, loops = 0;
421
422 do {
423 res_sendhookact act;
424
425 act = (*statp->qhook)(&nsap, &buf, &buflen,
426 ans, anssiz, &resplen);
427 switch (act) {
428 case res_goahead:
429 done = 1;
430 break;
431 case res_nextns:
432 res_nclose(statp);
433 goto next_ns;
434 case res_done:
435 return (resplen);
436 case res_modified:
437 /* give the hook another try */
438 if (++loops < 42) /*doug adams*/
439 break;
440 /*FALLTHROUGH*/
441 case res_error:
442 /*FALLTHROUGH*/
443 default:
444 goto fail;
445 }
446 } while (!done);
447 }
448
449 Dprint(((statp->options & RES_DEBUG) &&
450 getnameinfo(nsap, nsaplen, abuf, sizeof(abuf),
451 NULL, 0, niflags) == 0),
452 (stdout, ";; Querying server (# %d) address = %s\n",
453 ns + 1, abuf));
454
455
456 if (v_circuit) {
457 /* Use VC; at most one attempt per server. */
458 tries = statp->retry;
459 n = send_vc(statp, buf, buflen, ans, anssiz, &terrno,
460 ns);
461 if (n < 0)
462 goto fail;
463 if (n == 0)
464 goto next_ns;
465 resplen = n;
466 } else {
467 /* Use datagrams. */
468 n = send_dg(statp, buf, buflen, ans, anssiz, &terrno,
469 ns, tries, &v_circuit, &gotsomewhere);
470 if (n < 0)
471 goto fail;
472 if (n == 0)
473 goto next_ns;
474 if (v_circuit)
475 goto same_ns;
476 resplen = n;
477 }
478
479 Dprint((statp->options & RES_DEBUG) ||
480 ((statp->pfcode & RES_PRF_REPLY) &&
481 (statp->pfcode & RES_PRF_HEAD1)),
482 (stdout, ";; got answer:\n"));
483
484 DprintQ((statp->options & RES_DEBUG) ||
485 (statp->pfcode & RES_PRF_REPLY),
486 (stdout, "%s", ""),
487 ans, (resplen > anssiz) ? anssiz : resplen);
488
489 /*
490 * If we have temporarily opened a virtual circuit,
491 * or if we haven't been asked to keep a socket open,
492 * close the socket.
493 */
494 if ((v_circuit && (statp->options & RES_USEVC) == 0U) ||
495 (statp->options & RES_STAYOPEN) == 0U) {
496 res_nclose(statp);
497 }
498 if (statp->rhook) {
499 int done = 0, loops = 0;
500
501 do {
502 res_sendhookact act;
503
504 act = (*statp->rhook)(nsap, buf, buflen,
505 ans, anssiz, &resplen);
506 switch (act) {
507 case res_goahead:
508 case res_done:
509 done = 1;
510 break;
511 case res_nextns:
512 res_nclose(statp);
513 goto next_ns;
514 case res_modified:
515 /* give the hook another try */
516 if (++loops < 42) /*doug adams*/
517 break;
518 /*FALLTHROUGH*/
519 case res_error:
520 /*FALLTHROUGH*/
521 default:
522 goto fail;
523 }
524 } while (!done);
525
526 }
527 return (resplen);
528 next_ns: ;
529 } /*foreach ns*/
530 } /*foreach retry*/
531 res_nclose(statp);
532 if (!v_circuit) {
533 if (!gotsomewhere)
534 errno = ECONNREFUSED; /*%< no nameservers found */
535 else
536 errno = ETIMEDOUT; /*%< no answer obtained */
537 } else
538 errno = terrno;
539 return (-1);
540 fail:
541 res_nclose(statp);
542 return (-1);
543 }
544
545 /* Private */
546
547 static int
get_salen(sa)548 get_salen(sa)
549 const struct sockaddr *sa;
550 {
551
552 #ifdef HAVE_SA_LEN
553 /* There are people do not set sa_len. Be forgiving to them. */
554 if (sa->sa_len)
555 return (sa->sa_len);
556 #endif
557
558 if (sa->sa_family == AF_INET)
559 return (sizeof(struct sockaddr_in));
560 else if (sa->sa_family == AF_INET6)
561 return (sizeof(struct sockaddr_in6));
562 else
563 return (0); /*%< unknown, die on connect */
564 }
565
566 /*%
567 * pick appropriate nsaddr_list for use. see res_init() for initialization.
568 */
569 static struct sockaddr *
get_nsaddr(statp,n)570 get_nsaddr(statp, n)
571 res_state statp;
572 size_t n;
573 {
574
575 if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) {
576 /*
577 * - EXT(statp).ext->nsaddrs[n] holds an address that is larger
578 * than struct sockaddr, and
579 * - user code did not update statp->nsaddr_list[n].
580 */
581 return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n];
582 } else {
583 /*
584 * - user code updated statp->nsaddr_list[n], or
585 * - statp->nsaddr_list[n] has the same content as
586 * EXT(statp).ext->nsaddrs[n].
587 */
588 return (struct sockaddr *)(void *)&statp->nsaddr_list[n];
589 }
590 }
591
592 static int
send_vc(res_state statp,const u_char * buf,int buflen,u_char * ans,int anssiz,int * terrno,int ns)593 send_vc(res_state statp,
594 const u_char *buf, int buflen, u_char *ans, int anssiz,
595 int *terrno, int ns)
596 {
597 const HEADER *hp = (const HEADER *) buf;
598 HEADER *anhp = (HEADER *) ans;
599 struct sockaddr *nsap;
600 int nsaplen;
601 int truncating, connreset, resplen, n;
602 struct iovec iov[2];
603 u_short len;
604 u_char *cp;
605 void *tmp;
606 #ifdef SO_NOSIGPIPE
607 int on = 1;
608 #endif
609
610 nsap = get_nsaddr(statp, ns);
611 nsaplen = get_salen(nsap);
612
613 connreset = 0;
614 same_ns:
615 truncating = 0;
616
617 /* Are we still talking to whom we want to talk to? */
618 if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) {
619 struct sockaddr_storage peer;
620 ISC_SOCKLEN_T size = sizeof peer;
621
622 if (getpeername(statp->_vcsock,
623 (struct sockaddr *)&peer, &size) < 0 ||
624 !sock_eq((struct sockaddr *)&peer, nsap)) {
625 res_nclose(statp);
626 statp->_flags &= ~RES_F_VC;
627 }
628 }
629
630 if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) {
631 if (statp->_vcsock >= 0)
632 res_nclose(statp);
633
634 statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM, 0);
635 if (statp->_vcsock > highestFD) {
636 res_nclose(statp);
637 errno = ENOTSOCK;
638 }
639 if (statp->_vcsock < 0) {
640 switch (errno) {
641 case EPROTONOSUPPORT:
642 #ifdef EPFNOSUPPORT
643 case EPFNOSUPPORT:
644 #endif
645 case EAFNOSUPPORT:
646 Perror(statp, stderr, "socket(vc)", errno);
647 return (0);
648 default:
649 *terrno = errno;
650 Perror(statp, stderr, "socket(vc)", errno);
651 return (-1);
652 }
653 }
654 #ifdef SO_NOSIGPIPE
655 /*
656 * Disable generation of SIGPIPE when writing to a closed
657 * socket. Write should return -1 and set errno to EPIPE
658 * instead.
659 *
660 * Push on even if setsockopt(SO_NOSIGPIPE) fails.
661 */
662 (void)setsockopt(statp->_vcsock, SOL_SOCKET, SO_NOSIGPIPE, &on,
663 sizeof(on));
664 #endif
665 errno = 0;
666 if (connect(statp->_vcsock, nsap, nsaplen) < 0) {
667 *terrno = errno;
668 Aerror(statp, stderr, "connect/vc", errno, nsap,
669 nsaplen);
670 res_nclose(statp);
671 return (0);
672 }
673 statp->_flags |= RES_F_VC;
674 }
675
676 /*
677 * Send length & message
678 */
679 ns_put16((u_short)buflen, (u_char*)&len);
680 iov[0] = evConsIovec(&len, INT16SZ);
681 DE_CONST(buf, tmp);
682 iov[1] = evConsIovec(tmp, buflen);
683 if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) {
684 *terrno = errno;
685 Perror(statp, stderr, "write failed", errno);
686 res_nclose(statp);
687 return (0);
688 }
689 /*
690 * Receive length & response
691 */
692 read_len:
693 cp = ans;
694 len = INT16SZ;
695 while ((n = read(statp->_vcsock, (char *)cp, (int)len)) > 0) {
696 cp += n;
697 if ((len -= n) == 0)
698 break;
699 }
700 if (n <= 0) {
701 *terrno = errno;
702 Perror(statp, stderr, "read failed", errno);
703 res_nclose(statp);
704 /*
705 * A long running process might get its TCP
706 * connection reset if the remote server was
707 * restarted. Requery the server instead of
708 * trying a new one. When there is only one
709 * server, this means that a query might work
710 * instead of failing. We only allow one reset
711 * per query to prevent looping.
712 */
713 if (*terrno == ECONNRESET && !connreset) {
714 connreset = 1;
715 res_nclose(statp);
716 goto same_ns;
717 }
718 res_nclose(statp);
719 return (0);
720 }
721 resplen = ns_get16(ans);
722 if (resplen > anssiz) {
723 Dprint(statp->options & RES_DEBUG,
724 (stdout, ";; response truncated\n")
725 );
726 truncating = 1;
727 len = anssiz;
728 } else
729 len = resplen;
730 if (len < HFIXEDSZ) {
731 /*
732 * Undersized message.
733 */
734 Dprint(statp->options & RES_DEBUG,
735 (stdout, ";; undersized: %d\n", len));
736 *terrno = EMSGSIZE;
737 res_nclose(statp);
738 return (0);
739 }
740 cp = ans;
741 while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (int)len)) > 0){
742 cp += n;
743 len -= n;
744 }
745 if (n <= 0) {
746 *terrno = errno;
747 Perror(statp, stderr, "read(vc)", errno);
748 res_nclose(statp);
749 return (0);
750 }
751 if (truncating) {
752 /*
753 * Flush rest of answer so connection stays in synch.
754 */
755 anhp->tc = 1;
756 len = resplen - anssiz;
757 while (len != 0) {
758 char junk[PACKETSZ];
759
760 n = read(statp->_vcsock, junk,
761 (len > sizeof junk) ? sizeof junk : len);
762 if (n > 0)
763 len -= n;
764 else
765 break;
766 }
767 }
768 /*
769 * If the calling applicating has bailed out of
770 * a previous call and failed to arrange to have
771 * the circuit closed or the server has got
772 * itself confused, then drop the packet and
773 * wait for the correct one.
774 */
775 if (hp->id != anhp->id) {
776 DprintQ((statp->options & RES_DEBUG) ||
777 (statp->pfcode & RES_PRF_REPLY),
778 (stdout, ";; old answer (unexpected):\n"),
779 ans, (resplen > anssiz) ? anssiz: resplen);
780 goto read_len;
781 }
782
783 /*
784 * All is well, or the error is fatal. Signal that the
785 * next nameserver ought not be tried.
786 */
787 return (resplen);
788 }
789
790 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)791 send_dg(res_state statp, const u_char *buf, int buflen, u_char *ans,
792 int anssiz, int *terrno, int ns, int tries, int *v_circuit,
793 int *gotsomewhere)
794 {
795 const HEADER *hp = (const HEADER *) buf;
796 HEADER *anhp = (HEADER *) ans;
797 const struct sockaddr *nsap;
798 int nsaplen;
799 struct timespec now, timeout, finish;
800 struct sockaddr_storage from;
801 ISC_SOCKLEN_T fromlen;
802 int resplen, seconds, n, s;
803 #ifdef USE_POLL
804 int polltimeout;
805 struct pollfd pollfd;
806 #else
807 fd_set dsmask;
808 #endif
809
810 nsap = get_nsaddr(statp, ns);
811 nsaplen = get_salen(nsap);
812 if (EXT(statp).nssocks[ns] == -1) {
813 EXT(statp).nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM, 0);
814 if (EXT(statp).nssocks[ns] > highestFD) {
815 res_nclose(statp);
816 errno = ENOTSOCK;
817 }
818 if (EXT(statp).nssocks[ns] < 0) {
819 switch (errno) {
820 case EPROTONOSUPPORT:
821 #ifdef EPFNOSUPPORT
822 case EPFNOSUPPORT:
823 #endif
824 case EAFNOSUPPORT:
825 Perror(statp, stderr, "socket(dg)", errno);
826 return (0);
827 default:
828 *terrno = errno;
829 Perror(statp, stderr, "socket(dg)", errno);
830 return (-1);
831 }
832 }
833 #ifndef CANNOT_CONNECT_DGRAM
834 /*
835 * On a 4.3BSD+ machine (client and server,
836 * actually), sending to a nameserver datagram
837 * port with no nameserver will cause an
838 * ICMP port unreachable message to be returned.
839 * If our datagram socket is "connected" to the
840 * server, we get an ECONNREFUSED error on the next
841 * socket operation, and select returns if the
842 * error message is received. We can thus detect
843 * the absence of a nameserver without timing out.
844 */
845 if (connect(EXT(statp).nssocks[ns], nsap, nsaplen) < 0) {
846 Aerror(statp, stderr, "connect(dg)", errno, nsap,
847 nsaplen);
848 res_nclose(statp);
849 return (0);
850 }
851 #endif /* !CANNOT_CONNECT_DGRAM */
852 Dprint(statp->options & RES_DEBUG,
853 (stdout, ";; new DG socket\n"))
854 }
855 s = EXT(statp).nssocks[ns];
856 #ifndef CANNOT_CONNECT_DGRAM
857 if (send(s, (const char*)buf, buflen, 0) != buflen) {
858 Perror(statp, stderr, "send", errno);
859 res_nclose(statp);
860 return (0);
861 }
862 #else /* !CANNOT_CONNECT_DGRAM */
863 if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen)
864 {
865 Aerror(statp, stderr, "sendto", errno, nsap, nsaplen);
866 res_nclose(statp);
867 return (0);
868 }
869 #endif /* !CANNOT_CONNECT_DGRAM */
870
871 /*
872 * Wait for reply.
873 */
874 seconds = (statp->retrans << tries);
875 if (ns > 0)
876 seconds /= statp->nscount;
877 if (seconds <= 0)
878 seconds = 1;
879 now = evNowTime();
880 timeout = evConsTime(seconds, 0);
881 finish = evAddTime(now, timeout);
882 goto nonow;
883 wait:
884 now = evNowTime();
885 nonow:
886 #ifndef USE_POLL
887 FD_ZERO(&dsmask);
888 FD_SET(s, &dsmask);
889 if (evCmpTime(finish, now) > 0)
890 timeout = evSubTime(finish, now);
891 else
892 timeout = evConsTime(0, 0);
893 n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL);
894 #else
895 timeout = evSubTime(finish, now);
896 if (timeout.tv_sec < 0)
897 timeout = evConsTime(0, 0);
898 polltimeout = 1000*timeout.tv_sec +
899 timeout.tv_nsec/1000000;
900 pollfd.fd = s;
901 pollfd.events = POLLRDNORM;
902 n = poll(&pollfd, 1, polltimeout);
903 #endif /* USE_POLL */
904
905 if (n == 0) {
906 Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n"));
907 *gotsomewhere = 1;
908 return (0);
909 }
910 if (n < 0) {
911 if (errno == EINTR)
912 goto wait;
913 #ifndef USE_POLL
914 Perror(statp, stderr, "select", errno);
915 #else
916 Perror(statp, stderr, "poll", errno);
917 #endif /* USE_POLL */
918 res_nclose(statp);
919 return (0);
920 }
921 errno = 0;
922 fromlen = sizeof(from);
923 resplen = recvfrom(s, (char*)ans, anssiz,0,
924 (struct sockaddr *)&from, &fromlen);
925 if (resplen <= 0) {
926 Perror(statp, stderr, "recvfrom", errno);
927 res_nclose(statp);
928 return (0);
929 }
930 *gotsomewhere = 1;
931 if (resplen < HFIXEDSZ) {
932 /*
933 * Undersized message.
934 */
935 Dprint(statp->options & RES_DEBUG,
936 (stdout, ";; undersized: %d\n",
937 resplen));
938 *terrno = EMSGSIZE;
939 res_nclose(statp);
940 return (0);
941 }
942 if (hp->id != anhp->id) {
943 /*
944 * response from old query, ignore it.
945 * XXX - potential security hazard could
946 * be detected here.
947 */
948 DprintQ((statp->options & RES_DEBUG) ||
949 (statp->pfcode & RES_PRF_REPLY),
950 (stdout, ";; old answer:\n"),
951 ans, (resplen > anssiz) ? anssiz : resplen);
952 goto wait;
953 }
954 if (!(statp->options & RES_INSECURE1) &&
955 !res_ourserver_p(statp, (struct sockaddr *)&from)) {
956 /*
957 * response from wrong server? ignore it.
958 * XXX - potential security hazard could
959 * be detected here.
960 */
961 DprintQ((statp->options & RES_DEBUG) ||
962 (statp->pfcode & RES_PRF_REPLY),
963 (stdout, ";; not our server:\n"),
964 ans, (resplen > anssiz) ? anssiz : resplen);
965 goto wait;
966 }
967 #ifdef RES_USE_EDNS0
968 if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) {
969 /*
970 * Do not retry if the server do not understand EDNS0.
971 * The case has to be captured here, as FORMERR packet do not
972 * carry query section, hence res_queriesmatch() returns 0.
973 */
974 DprintQ(statp->options & RES_DEBUG,
975 (stdout, "server rejected query with EDNS0:\n"),
976 ans, (resplen > anssiz) ? anssiz : resplen);
977 /* record the error */
978 statp->_flags |= RES_F_EDNS0ERR;
979 res_nclose(statp);
980 return (0);
981 }
982 #endif
983 if (!(statp->options & RES_INSECURE2) &&
984 !res_queriesmatch(buf, buf + buflen,
985 ans, ans + anssiz)) {
986 /*
987 * response contains wrong query? ignore it.
988 * XXX - potential security hazard could
989 * be detected here.
990 */
991 DprintQ((statp->options & RES_DEBUG) ||
992 (statp->pfcode & RES_PRF_REPLY),
993 (stdout, ";; wrong query name:\n"),
994 ans, (resplen > anssiz) ? anssiz : resplen);
995 goto wait;
996 }
997 if (anhp->rcode == SERVFAIL ||
998 anhp->rcode == NOTIMP ||
999 anhp->rcode == REFUSED) {
1000 DprintQ(statp->options & RES_DEBUG,
1001 (stdout, "server rejected query:\n"),
1002 ans, (resplen > anssiz) ? anssiz : resplen);
1003 res_nclose(statp);
1004 /* don't retry if called from dig */
1005 if (!statp->pfcode)
1006 return (0);
1007 }
1008 if (!(statp->options & RES_IGNTC) && anhp->tc) {
1009 /*
1010 * To get the rest of answer,
1011 * use TCP with same server.
1012 */
1013 Dprint(statp->options & RES_DEBUG,
1014 (stdout, ";; truncated answer\n"));
1015 *v_circuit = 1;
1016 res_nclose(statp);
1017 return (1);
1018 }
1019 /*
1020 * All is well, or the error is fatal. Signal that the
1021 * next nameserver ought not be tried.
1022 */
1023 return (resplen);
1024 }
1025
1026 static void
Aerror(const res_state statp,FILE * file,const char * string,int error,const struct sockaddr * address,int alen)1027 Aerror(const res_state statp, FILE *file, const char *string, int error,
1028 const struct sockaddr *address, int alen)
1029 {
1030 int save = errno;
1031 char hbuf[NI_MAXHOST];
1032 char sbuf[NI_MAXSERV];
1033
1034 alen = alen;
1035
1036 if ((statp->options & RES_DEBUG) != 0U) {
1037 if (getnameinfo(address, alen, hbuf, sizeof(hbuf),
1038 sbuf, sizeof(sbuf), niflags)) {
1039 strncpy(hbuf, "?", sizeof(hbuf) - 1);
1040 hbuf[sizeof(hbuf) - 1] = '\0';
1041 strncpy(sbuf, "?", sizeof(sbuf) - 1);
1042 sbuf[sizeof(sbuf) - 1] = '\0';
1043 }
1044 fprintf(file, "res_send: %s ([%s].%s): %s\n",
1045 string, hbuf, sbuf, strerror(error));
1046 }
1047 errno = save;
1048 }
1049
1050 static void
Perror(const res_state statp,FILE * file,const char * string,int error)1051 Perror(const res_state statp, FILE *file, const char *string, int error) {
1052 int save = errno;
1053
1054 if ((statp->options & RES_DEBUG) != 0U)
1055 fprintf(file, "res_send: %s: %s\n",
1056 string, strerror(error));
1057 errno = save;
1058 }
1059
1060 static int
sock_eq(struct sockaddr * a,struct sockaddr * b)1061 sock_eq(struct sockaddr *a, struct sockaddr *b) {
1062 struct sockaddr_in *a4, *b4;
1063 struct sockaddr_in6 *a6, *b6;
1064
1065 if (a->sa_family != b->sa_family)
1066 return 0;
1067 switch (a->sa_family) {
1068 case AF_INET:
1069 a4 = (struct sockaddr_in *)a;
1070 b4 = (struct sockaddr_in *)b;
1071 return a4->sin_port == b4->sin_port &&
1072 a4->sin_addr.s_addr == b4->sin_addr.s_addr;
1073 case AF_INET6:
1074 a6 = (struct sockaddr_in6 *)a;
1075 b6 = (struct sockaddr_in6 *)b;
1076 return a6->sin6_port == b6->sin6_port &&
1077 #ifdef HAVE_SIN6_SCOPE_ID
1078 a6->sin6_scope_id == b6->sin6_scope_id &&
1079 #endif
1080 IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr);
1081 default:
1082 return 0;
1083 }
1084 }
1085
1086 #if defined(NEED_PSELECT) && !defined(USE_POLL)
1087 /* XXX needs to move to the porting library. */
1088 static int
pselect(int nfds,void * rfds,void * wfds,void * efds,struct timespec * tsp,const sigset_t * sigmask)1089 pselect(int nfds, void *rfds, void *wfds, void *efds,
1090 struct timespec *tsp, const sigset_t *sigmask)
1091 {
1092 struct timeval tv, *tvp;
1093 sigset_t sigs;
1094 int n;
1095
1096 if (tsp) {
1097 tvp = &tv;
1098 tv = evTimeVal(*tsp);
1099 } else
1100 tvp = NULL;
1101 if (sigmask)
1102 sigprocmask(SIG_SETMASK, sigmask, &sigs);
1103 n = select(nfds, rfds, wfds, efds, tvp);
1104 if (sigmask)
1105 sigprocmask(SIG_SETMASK, &sigs, NULL);
1106 if (tsp)
1107 *tsp = evTimeSpec(tv);
1108 return (n);
1109 }
1110 #endif
1111