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-rw-r--r--src/lib/libc/net/res_send.c879
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diff --git a/src/lib/libc/net/res_send.c b/src/lib/libc/net/res_send.c
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+++ b/src/lib/libc/net/res_send.c
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1/* $OpenBSD: res_send.c,v 1.18 2005/03/30 02:58:28 tedu Exp $ */
2
3/*
4 * ++Copyright++ 1985, 1989, 1993
5 * -
6 * Copyright (c) 1985, 1989, 1993
7 * The Regents of the University of California. All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 * -
33 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
34 *
35 * Permission to use, copy, modify, and distribute this software for any
36 * purpose with or without fee is hereby granted, provided that the above
37 * copyright notice and this permission notice appear in all copies, and that
38 * the name of Digital Equipment Corporation not be used in advertising or
39 * publicity pertaining to distribution of the document or software without
40 * specific, written prior permission.
41 *
42 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
43 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
44 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
45 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
46 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
47 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
48 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
49 * SOFTWARE.
50 * -
51 * --Copyright--
52 */
53
54#ifndef INET6
55#define INET6
56#endif
57
58#if defined(LIBC_SCCS) && !defined(lint)
59#if 0
60static char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
61static char rcsid[] = "$From: res_send.c,v 8.12 1996/10/08 04:51:06 vixie Exp $";
62#else
63static char rcsid[] = "$OpenBSD: res_send.c,v 1.18 2005/03/30 02:58:28 tedu Exp $";
64#endif
65#endif /* LIBC_SCCS and not lint */
66
67 /* change this to "0"
68 * if you talk to a lot
69 * of multi-homed SunOS
70 * ("broken") name servers.
71 */
72#define CHECK_SRVR_ADDR 1 /* XXX - should be in options.h */
73
74/*
75 * Send query to name server and wait for reply.
76 */
77
78#include <sys/types.h>
79#include <sys/param.h>
80#include <sys/time.h>
81#include <sys/socket.h>
82#include <sys/uio.h>
83#include <netinet/in.h>
84#include <arpa/nameser.h>
85#include <arpa/inet.h>
86
87#include <stdio.h>
88#include <netdb.h>
89#include <errno.h>
90#include <resolv.h>
91#include <stdlib.h>
92#include <string.h>
93#include <unistd.h>
94
95#include "thread_private.h"
96
97static int s = -1; /* socket used for communications */
98static int connected = 0; /* is the socket connected */
99static int vc = 0; /* is the socket a virtual ciruit? */
100static int af = 0; /* address family of socket */
101
102#ifndef FD_SET
103/* XXX - should be in portability.h */
104#define NFDBITS 32
105#define FD_SETSIZE 32
106#define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
107#define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
108#define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
109#define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))
110#endif
111
112#define CAN_RECONNECT 1
113
114#ifndef DEBUG
115# define Dprint(cond, args) /*empty*/
116# define DprintQ(cond, args, query, size) /*empty*/
117# define Aerror(file, string, error, address) /*empty*/
118# define Perror(file, string, error) /*empty*/
119#else
120# define Dprint(cond, args) if (cond) {fprintf args;} else {}
121# define DprintQ(cond, args, query, size) if (cond) {\
122 fprintf args;\
123 __fp_nquery(query, size, stdout);\
124 } else {}
125static char abuf[NI_MAXHOST];
126static char pbuf[NI_MAXSERV];
127static void Aerror(FILE *, char *, int, struct sockaddr *);
128static void Perror(FILE *, char *, int);
129
130 static void
131 Aerror(FILE *file, char *string, int error, struct sockaddr *address)
132 {
133 struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
134 int save = errno;
135
136 if (_resp->options & RES_DEBUG) {
137 if (getnameinfo(address, address->sa_len, abuf, sizeof(abuf),
138 pbuf, sizeof(pbuf), NI_NUMERICHOST | NI_NUMERICSERV) != 0) {
139 strlcpy(abuf, "?", sizeof(abuf));
140 strlcpy(pbuf, "?", sizeof(pbuf));
141 }
142 fprintf(file, "res_send: %s ([%s].%s): %s\n",
143 string, abuf, pbuf, strerror(error));
144 }
145 errno = save;
146 }
147 static void
148 Perror(FILE *file, char *string, int error)
149 {
150 struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
151 int save = errno;
152
153 if (_resp->options & RES_DEBUG) {
154 fprintf(file, "res_send: %s: %s\n",
155 string, strerror(error));
156 }
157 errno = save;
158 }
159#endif
160
161static res_send_qhook Qhook = NULL;
162static res_send_rhook Rhook = NULL;
163
164void
165res_send_setqhook(res_send_qhook hook)
166{
167
168 Qhook = hook;
169}
170
171void
172res_send_setrhook(res_send_rhook hook)
173{
174
175 Rhook = hook;
176}
177
178#ifdef INET6
179static struct sockaddr * get_nsaddr(size_t);
180
181/*
182 * pick appropriate nsaddr_list for use. see res_init() for initialization.
183 */
184static struct sockaddr *
185get_nsaddr(size_t n)
186{
187 struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
188 struct __res_state_ext *_res_extp = _THREAD_PRIVATE(_res_ext, _res_ext,
189 &_res_ext);
190
191 if (!_resp->nsaddr_list[n].sin_family) {
192 /*
193 * - _res_extp->nsaddr_list[n] holds an address that is larger
194 * than struct sockaddr, and
195 * - user code did not update _resp->nsaddr_list[n].
196 */
197 return (struct sockaddr *)&_res_extp->nsaddr_list[n];
198 } else {
199 /*
200 * - user code updated _res.nsaddr_list[n], or
201 * - _resp->nsaddr_list[n] has the same content as
202 * _res_extp->nsaddr_list[n].
203 */
204 return (struct sockaddr *)&_resp->nsaddr_list[n];
205 }
206}
207#else
208#define get_nsaddr(n) ((struct sockaddr *)&_resp->nsaddr_list[(n)])
209#endif
210
211/* int
212 * res_isourserver(ina)
213 * looks up "ina" in _resp->ns_addr_list[]
214 * returns:
215 * 0 : not found
216 * >0 : found
217 * author:
218 * paul vixie, 29may94
219 */
220int
221res_isourserver(const struct sockaddr_in *inp)
222{
223 struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
224#ifdef INET6
225 const struct sockaddr_in6 *in6p = (const struct sockaddr_in6 *)inp;
226 const struct sockaddr_in6 *srv6;
227#endif
228 const struct sockaddr_in *srv;
229 int ns, ret;
230
231 ret = 0;
232 switch (inp->sin_family) {
233#ifdef INET6
234 case AF_INET6:
235 for (ns = 0; ns < _resp->nscount; ns++) {
236 srv6 = (struct sockaddr_in6 *)get_nsaddr(ns);
237 if (srv6->sin6_family == in6p->sin6_family &&
238 srv6->sin6_port == in6p->sin6_port &&
239 srv6->sin6_scope_id == in6p->sin6_scope_id &&
240 (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) ||
241 IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr,
242 &in6p->sin6_addr))) {
243 ret++;
244 break;
245 }
246 }
247 break;
248#endif
249 case AF_INET:
250 for (ns = 0; ns < _resp->nscount; ns++) {
251 srv = (struct sockaddr_in *)get_nsaddr(ns);
252 if (srv->sin_family == inp->sin_family &&
253 srv->sin_port == inp->sin_port &&
254 (srv->sin_addr.s_addr == INADDR_ANY ||
255 srv->sin_addr.s_addr == inp->sin_addr.s_addr)) {
256 ret++;
257 break;
258 }
259 }
260 break;
261 }
262 return (ret);
263}
264
265/* int
266 * res_nameinquery(name, type, class, buf, eom)
267 * look for (name,type,class) in the query section of packet (buf,eom)
268 * returns:
269 * -1 : format error
270 * 0 : not found
271 * >0 : found
272 * author:
273 * paul vixie, 29may94
274 */
275int
276res_nameinquery(const char *name, int type, int class, const u_char *buf,
277 const u_char *eom)
278{
279 const u_char *cp = buf + HFIXEDSZ;
280 int qdcount = ntohs(((HEADER*)buf)->qdcount);
281
282 while (qdcount-- > 0) {
283 char tname[MAXDNAME+1];
284 int n, ttype, tclass;
285
286 n = dn_expand(buf, eom, cp, tname, sizeof tname);
287 if (n < 0)
288 return (-1);
289 cp += n;
290 ttype = _getshort(cp); cp += INT16SZ;
291 tclass = _getshort(cp); cp += INT16SZ;
292 if (ttype == type &&
293 tclass == class &&
294 strcasecmp(tname, name) == 0)
295 return (1);
296 }
297 return (0);
298}
299
300/* int
301 * res_queriesmatch(buf1, eom1, buf2, eom2)
302 * is there a 1:1 mapping of (name,type,class)
303 * in (buf1,eom1) and (buf2,eom2)?
304 * returns:
305 * -1 : format error
306 * 0 : not a 1:1 mapping
307 * >0 : is a 1:1 mapping
308 * author:
309 * paul vixie, 29may94
310 */
311int
312res_queriesmatch(const u_char *buf1, const u_char *eom1, const u_char *buf2,
313 const u_char *eom2)
314{
315 const u_char *cp = buf1 + HFIXEDSZ;
316 int qdcount = ntohs(((HEADER*)buf1)->qdcount);
317
318 if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
319 return (0);
320 while (qdcount-- > 0) {
321 char tname[MAXDNAME+1];
322 int n, ttype, tclass;
323
324 n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
325 if (n < 0)
326 return (-1);
327 cp += n;
328 ttype = _getshort(cp); cp += INT16SZ;
329 tclass = _getshort(cp); cp += INT16SZ;
330 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
331 return (0);
332 }
333 return (1);
334}
335
336int
337res_send(const u_char *buf, int buflen, u_char *ans, int anssiz)
338{
339 struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
340 HEADER *hp = (HEADER *) buf;
341 HEADER *anhp = (HEADER *) ans;
342 int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns;
343 int n;
344 u_int badns; /* XXX NSMAX can't exceed #/bits in this var */
345
346 if (_res_init(0) == -1) {
347 /* errno should have been set by res_init() in this case. */
348 return (-1);
349 }
350 DprintQ((_resp->options & RES_DEBUG) || (_resp->pfcode & RES_PRF_QUERY),
351 (stdout, ";; res_send()\n"), buf, buflen);
352 v_circuit = (_resp->options & RES_USEVC) || buflen > PACKETSZ;
353 gotsomewhere = 0;
354 connreset = 0;
355 terrno = ETIMEDOUT;
356 badns = 0;
357
358 /*
359 * Send request, RETRY times, or until successful
360 */
361 for (try = 0; try < _resp->retry; try++) {
362 for (ns = 0; ns < _resp->nscount; ns++) {
363 struct sockaddr *nsap = get_nsaddr(ns);
364 socklen_t salen;
365
366 if (nsap->sa_len)
367 salen = nsap->sa_len;
368#ifdef INET6
369 else if (nsap->sa_family == AF_INET6)
370 salen = sizeof(struct sockaddr_in6);
371#endif
372 else if (nsap->sa_family == AF_INET)
373 salen = sizeof(struct sockaddr_in);
374 else
375 salen = 0; /*unknown, die on connect*/
376
377 same_ns:
378 if (badns & (1 << ns)) {
379 res_close();
380 goto next_ns;
381 }
382
383 if (Qhook) {
384 int done = 0, loops = 0;
385
386 do {
387 res_sendhookact act;
388
389 act = (*Qhook)((struct sockaddr_in **)&nsap,
390 &buf, &buflen,
391 ans, anssiz, &resplen);
392 switch (act) {
393 case res_goahead:
394 done = 1;
395 break;
396 case res_nextns:
397 res_close();
398 goto next_ns;
399 case res_done:
400 return (resplen);
401 case res_modified:
402 /* give the hook another try */
403 if (++loops < 42) /*doug adams*/
404 break;
405 /*FALLTHROUGH*/
406 case res_error:
407 /*FALLTHROUGH*/
408 default:
409 return (-1);
410 }
411 } while (!done);
412 }
413
414 Dprint((_resp->options & RES_DEBUG) &&
415 getnameinfo(nsap, salen, abuf, sizeof(abuf),
416 NULL, 0, NI_NUMERICHOST) == 0,
417 (stdout, ";; Querying server (# %d) address = %s\n",
418 ns + 1, abuf));
419
420 if (v_circuit) {
421 int truncated;
422 struct iovec iov[2];
423 u_short len;
424 u_char *cp;
425
426 /*
427 * Use virtual circuit;
428 * at most one attempt per server.
429 */
430 try = _resp->retry;
431 truncated = 0;
432 if ((s < 0) || (!vc) || (af != nsap->sa_family)) {
433 if (s >= 0)
434 res_close();
435
436 af = nsap->sa_family;
437 s = socket(af, SOCK_STREAM, 0);
438 if (s < 0) {
439 terrno = errno;
440 Perror(stderr, "socket(vc)", errno);
441#if 0
442 return (-1);
443#else
444 badns |= (1 << ns);
445 res_close();
446 goto next_ns;
447#endif
448 }
449 errno = 0;
450 if (connect(s, nsap, salen) < 0) {
451 terrno = errno;
452 Aerror(stderr, "connect/vc",
453 errno, nsap);
454 badns |= (1 << ns);
455 res_close();
456 goto next_ns;
457 }
458 vc = 1;
459 }
460 /*
461 * Send length & message
462 */
463 putshort((u_short)buflen, (u_char*)&len);
464 iov[0].iov_base = (caddr_t)&len;
465 iov[0].iov_len = INT16SZ;
466 iov[1].iov_base = (caddr_t)buf;
467 iov[1].iov_len = buflen;
468 if (writev(s, iov, 2) != (INT16SZ + buflen)) {
469 terrno = errno;
470 Perror(stderr, "write failed", errno);
471 badns |= (1 << ns);
472 res_close();
473 goto next_ns;
474 }
475 /*
476 * Receive length & response
477 */
478read_len:
479 cp = ans;
480 len = INT16SZ;
481 while ((n = read(s, (char *)cp, (int)len)) > 0) {
482 cp += n;
483 if ((len -= n) <= 0)
484 break;
485 }
486 if (n <= 0) {
487 terrno = errno;
488 Perror(stderr, "read failed", errno);
489 res_close();
490 /*
491 * A long running process might get its TCP
492 * connection reset if the remote server was
493 * restarted. Requery the server instead of
494 * trying a new one. When there is only one
495 * server, this means that a query might work
496 * instead of failing. We only allow one reset
497 * per query to prevent looping.
498 */
499 if (terrno == ECONNRESET && !connreset) {
500 connreset = 1;
501 res_close();
502 goto same_ns;
503 }
504 res_close();
505 goto next_ns;
506 }
507 resplen = _getshort(ans);
508 if (resplen > anssiz) {
509 Dprint(_resp->options & RES_DEBUG,
510 (stdout, ";; response truncated\n")
511 );
512 truncated = 1;
513 len = anssiz;
514 } else
515 len = resplen;
516 cp = ans;
517 while (len != 0 &&
518 (n = read(s, (char *)cp, (int)len)) > 0) {
519 cp += n;
520 len -= n;
521 }
522 if (n <= 0) {
523 terrno = errno;
524 Perror(stderr, "read(vc)", errno);
525 res_close();
526 goto next_ns;
527 }
528 if (truncated) {
529 /*
530 * Flush rest of answer
531 * so connection stays in synch.
532 */
533 anhp->tc = 1;
534 len = resplen - anssiz;
535 while (len != 0) {
536 char junk[PACKETSZ];
537
538 n = (len > sizeof(junk)
539 ? sizeof(junk)
540 : len);
541 if ((n = read(s, junk, n)) > 0)
542 len -= n;
543 else
544 break;
545 }
546 }
547 /*
548 * The calling applicating has bailed out of
549 * a previous call and failed to arrange to have
550 * the circuit closed or the server has got
551 * itself confused. Anyway drop the packet and
552 * wait for the correct one.
553 */
554 if (hp->id != anhp->id) {
555 DprintQ((_resp->options & RES_DEBUG) ||
556 (_resp->pfcode & RES_PRF_REPLY),
557 (stdout, ";; old answer (unexpected):\n"),
558 ans, (resplen>anssiz)?anssiz:resplen);
559 goto read_len;
560 }
561 } else {
562 /*
563 * Use datagrams.
564 */
565 struct timeval timeout;
566 fd_set *dsmaskp;
567 struct sockaddr_storage from;
568 socklen_t fromlen;
569
570 if ((s < 0) || vc || (af != nsap->sa_family)) {
571 if (vc)
572 res_close();
573 af = nsap->sa_family;
574 s = socket(af, SOCK_DGRAM, 0);
575 if (s < 0) {
576#if !CAN_RECONNECT
577 bad_dg_sock:
578#endif
579 terrno = errno;
580 Perror(stderr, "socket(dg)", errno);
581#if 0
582 return (-1);
583#else
584 badns |= (1 << ns);
585 res_close();
586 goto next_ns;
587#endif
588 }
589#ifdef IPV6_MINMTU
590 if (af == AF_INET6) {
591 const int yes = 1;
592 (void)setsockopt(s, IPPROTO_IPV6,
593 IPV6_USE_MIN_MTU, &yes,
594 sizeof(yes));
595 }
596#endif
597 connected = 0;
598 }
599 /*
600 * On a 4.3BSD+ machine (client and server,
601 * actually), sending to a nameserver datagram
602 * port with no nameserver will cause an
603 * ICMP port unreachable message to be returned.
604 * If our datagram socket is "connected" to the
605 * server, we get an ECONNREFUSED error on the next
606 * socket operation, and select returns if the
607 * error message is received. We can thus detect
608 * the absence of a nameserver without timing out.
609 * If we have sent queries to at least two servers,
610 * however, we don't want to remain connected,
611 * as we wish to receive answers from the first
612 * server to respond.
613 */
614 if (!(_resp->options & RES_INSECURE1) &&
615 (_resp->nscount == 1 || (try == 0 && ns == 0))) {
616 /*
617 * Connect only if we are sure we won't
618 * receive a response from another server.
619 */
620 if (!connected) {
621 if (connect(s, nsap, salen) < 0) {
622 Aerror(stderr,
623 "connect(dg)",
624 errno, nsap);
625 badns |= (1 << ns);
626 res_close();
627 goto next_ns;
628 }
629 connected = 1;
630 }
631 if (send(s, (char*)buf, buflen, 0) != buflen) {
632 Perror(stderr, "send", errno);
633 badns |= (1 << ns);
634 res_close();
635 goto next_ns;
636 }
637 } else {
638 /*
639 * Disconnect if we want to listen
640 * for responses from more than one server.
641 */
642 if (connected) {
643#if CAN_RECONNECT
644#ifdef INET6
645 /* XXX: any errornous address */
646#endif /* INET6 */
647 struct sockaddr_in no_addr;
648
649 no_addr.sin_family = AF_INET;
650 no_addr.sin_addr.s_addr = INADDR_ANY;
651 no_addr.sin_port = 0;
652 (void) connect(s,
653 (struct sockaddr *)
654 &no_addr,
655 sizeof(no_addr));
656#else
657 int s1 = socket(af, SOCK_DGRAM,0);
658 if (s1 < 0)
659 goto bad_dg_sock;
660 (void) dup2(s1, s);
661 (void) close(s1);
662 Dprint(_resp->options & RES_DEBUG,
663 (stdout, ";; new DG socket\n"))
664#endif
665#ifdef IPV6_MINMTU
666 if (af == AF_INET6) {
667 const int yes = 1;
668 (void)setsockopt(s, IPPROTO_IPV6,
669 IPV6_USE_MIN_MTU, &yes,
670 sizeof(yes));
671 }
672#endif
673 connected = 0;
674 errno = 0;
675 }
676 if (sendto(s, (char*)buf, buflen, 0,
677 nsap, salen) != buflen) {
678 Aerror(stderr, "sendto", errno, nsap);
679 badns |= (1 << ns);
680 res_close();
681 goto next_ns;
682 }
683 }
684
685 /*
686 * Wait for reply
687 */
688 timeout.tv_sec = (_resp->retrans << try);
689 if (try > 0)
690 timeout.tv_sec /= _resp->nscount;
691 if ((long) timeout.tv_sec <= 0)
692 timeout.tv_sec = 1;
693 timeout.tv_usec = 0;
694 wait:
695 dsmaskp = (fd_set *)calloc(howmany(s+1, NFDBITS),
696 sizeof(fd_mask));
697 if (dsmaskp == NULL) {
698 res_close();
699 goto next_ns;
700 }
701 FD_SET(s, dsmaskp);
702 n = select(s+1, dsmaskp, (fd_set *)NULL,
703 (fd_set *)NULL, &timeout);
704 free(dsmaskp);
705 if (n < 0) {
706 if (errno == EINTR)
707 goto wait;
708 Perror(stderr, "select", errno);
709 res_close();
710 goto next_ns;
711 }
712 if (n == 0) {
713 /*
714 * timeout
715 */
716 Dprint(_resp->options & RES_DEBUG,
717 (stdout, ";; timeout\n"));
718 gotsomewhere = 1;
719 res_close();
720 goto next_ns;
721 }
722 errno = 0;
723 fromlen = sizeof(from);
724 resplen = recvfrom(s, (char*)ans, anssiz, 0,
725 (struct sockaddr *)&from, &fromlen);
726 if (resplen <= 0) {
727 Perror(stderr, "recvfrom", errno);
728 res_close();
729 goto next_ns;
730 }
731 gotsomewhere = 1;
732 if (hp->id != anhp->id) {
733 /*
734 * response from old query, ignore it.
735 * XXX - potential security hazard could
736 * be detected here.
737 */
738 DprintQ((_resp->options & RES_DEBUG) ||
739 (_resp->pfcode & RES_PRF_REPLY),
740 (stdout, ";; old answer:\n"),
741 ans, (resplen>anssiz)?anssiz:resplen);
742 goto wait;
743 }
744#if CHECK_SRVR_ADDR
745 if (!(_resp->options & RES_INSECURE1) &&
746 !res_isourserver((struct sockaddr_in *)&from)) {
747 /*
748 * response from wrong server? ignore it.
749 * XXX - potential security hazard could
750 * be detected here.
751 */
752 DprintQ((_resp->options & RES_DEBUG) ||
753 (_resp->pfcode & RES_PRF_REPLY),
754 (stdout, ";; not our server:\n"),
755 ans, (resplen>anssiz)?anssiz:resplen);
756 goto wait;
757 }
758#endif
759 if (!(_resp->options & RES_INSECURE2) &&
760 !res_queriesmatch(buf, buf + buflen,
761 ans, ans + anssiz)) {
762 /*
763 * response contains wrong query? ignore it.
764 * XXX - potential security hazard could
765 * be detected here.
766 */
767 DprintQ((_resp->options & RES_DEBUG) ||
768 (_resp->pfcode & RES_PRF_REPLY),
769 (stdout, ";; wrong query name:\n"),
770 ans, (resplen>anssiz)?anssiz:resplen);
771 goto wait;
772 }
773 if (anhp->rcode == SERVFAIL ||
774 anhp->rcode == NOTIMP ||
775 anhp->rcode == REFUSED) {
776 DprintQ(_resp->options & RES_DEBUG,
777 (stdout, "server rejected query:\n"),
778 ans, (resplen>anssiz)?anssiz:resplen);
779 badns |= (1 << ns);
780 res_close();
781 /* don't retry if called from dig */
782 if (!_resp->pfcode)
783 goto next_ns;
784 }
785 if (!(_resp->options & RES_IGNTC) && anhp->tc) {
786 /*
787 * get rest of answer;
788 * use TCP with same server.
789 */
790 Dprint(_resp->options & RES_DEBUG,
791 (stdout, ";; truncated answer\n"));
792 v_circuit = 1;
793 res_close();
794 goto same_ns;
795 }
796 } /*if vc/dg*/
797 Dprint((_resp->options & RES_DEBUG) ||
798 ((_resp->pfcode & RES_PRF_REPLY) &&
799 (_resp->pfcode & RES_PRF_HEAD1)),
800 (stdout, ";; got answer:\n"));
801 DprintQ((_resp->options & RES_DEBUG) ||
802 (_resp->pfcode & RES_PRF_REPLY),
803 (stdout, "%s", ""),
804 ans, (resplen>anssiz)?anssiz:resplen);
805 /*
806 * If using virtual circuits, we assume that the first server
807 * is preferred over the rest (i.e. it is on the local
808 * machine) and only keep that one open.
809 * If we have temporarily opened a virtual circuit,
810 * or if we haven't been asked to keep a socket open,
811 * close the socket.
812 */
813 if ((v_circuit && (!(_resp->options & RES_USEVC) || ns != 0)) ||
814 !(_resp->options & RES_STAYOPEN)) {
815 res_close();
816 }
817 if (Rhook) {
818 int done = 0, loops = 0;
819
820 do {
821 res_sendhookact act;
822
823 act = (*Rhook)((struct sockaddr_in *)nsap,
824 buf, buflen,
825 ans, anssiz, &resplen);
826 switch (act) {
827 case res_goahead:
828 case res_done:
829 done = 1;
830 break;
831 case res_nextns:
832 res_close();
833 goto next_ns;
834 case res_modified:
835 /* give the hook another try */
836 if (++loops < 42) /*doug adams*/
837 break;
838 /*FALLTHROUGH*/
839 case res_error:
840 /*FALLTHROUGH*/
841 default:
842 return (-1);
843 }
844 } while (!done);
845
846 }
847 return (resplen);
848 next_ns: ;
849 } /*foreach ns*/
850 } /*foreach retry*/
851 res_close();
852 if (!v_circuit) {
853 if (!gotsomewhere)
854 errno = ECONNREFUSED; /* no nameservers found */
855 else
856 errno = ETIMEDOUT; /* no answer obtained */
857 } else
858 errno = terrno;
859 return (-1);
860}
861
862/*
863 * This routine is for closing the socket if a virtual circuit is used and
864 * the program wants to close it. This provides support for endhostent()
865 * which expects to close the socket.
866 *
867 * This routine is not expected to be user visible.
868 */
869void
870res_close(void)
871{
872 if (s >= 0) {
873 (void) close(s);
874 s = -1;
875 connected = 0;
876 vc = 0;
877 af = 0;
878 }
879}
generated by cgit v1.2.3-55-g6feb (git 2.39.1) at 2025-05-03 11:25:29 +0000