1 /*
2 * ++Copyright++ 1985, 1989, 1993
3 * -
4 * Copyright (c) 1985, 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by the University of
18 * California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 * -
35 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
36 *
37 * Permission to use, copy, modify, and distribute this software for any
38 * purpose with or without fee is hereby granted, provided that the above
39 * copyright notice and this permission notice appear in all copies, and that
40 * the name of Digital Equipment Corporation not be used in advertising or
41 * publicity pertaining to distribution of the document or software without
42 * specific, written prior permission.
43 *
44 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
45 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
46 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
47 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
48 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
49 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
50 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
51 * SOFTWARE.
52 * -
53 * --Copyright--
54 */
55
56 #if defined(LIBC_SCCS) && !defined(lint)
57 static char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
58 static char rcsid[] = "$Id: res_send.c,v 8.13 1997/06/01 20:34:37 vixie Exp $";
59 #endif /* LIBC_SCCS and not lint */
60
61 /* change this to "0"
62 * if you talk to a lot
63 * of multi-homed SunOS
64 * ("broken") name servers.
65 */
66 #define CHECK_SRVR_ADDR 1 /* XXX - should be in options.h */
67
68 /*
69 * Send query to name server and wait for reply.
70 */
71
72 #include <sys/types.h>
73 #include <sys/param.h>
74 #include <sys/time.h>
75 #include <sys/socket.h>
76 #include <sys/uio.h>
77 #include <netinet/in.h>
78 #include <arpa/nameser.h>
79 #include <arpa/inet.h>
80
81 #include <stdio.h>
82 #include <netdb.h>
83 #include <errno.h>
84 #include <resolv.h>
85 #if defined(BSD) && (BSD >= 199306)
86 # include <stdlib.h>
87 # include <string.h>
88 # include <unistd.h>
89 #else
90 # include "../conf/portability.h"
91 #endif
92
93 #if defined(USE_OPTIONS_H)
94 # include <../conf/options.h>
95 #endif
96
97 static int s = -1; /* socket used for communications */
98 static int connected = 0; /* is the socket connected */
99 static int vc = 0; /* is the socket a virtual ciruit? */
100
101 #ifndef FD_SET
102 /* XXX - should be in portability.h */
103 #define NFDBITS 32
104 #define FD_SETSIZE 32
105 #define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
106 #define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
107 #define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
108 #define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))
109 #endif
110
111 /* XXX - this should be done in portability.h */
112 #if (defined(BSD) && (BSD >= 199103)) || defined(linux)
113 # define CAN_RECONNECT 1
114 #else
115 # define CAN_RECONNECT 0
116 #endif
117
118 #ifndef DEBUG
119 # define Dprint(cond, args) /*empty*/
120 # define DprintQ(cond, args, query, size) /*empty*/
121 # define Aerror(file, string, error, address) /*empty*/
122 # define Perror(file, string, error) /*empty*/
123 #else
124 # define Dprint(cond, args) if (cond) {fprintf args;} else {}
125 # define DprintQ(cond, args, query, size) if (cond) {\
126 fprintf args;\
127 __fp_nquery(query, size, stdout);\
128 } else {}
129 static void
Aerror(file,string,error,address)130 Aerror(file, string, error, address)
131 FILE *file;
132 char *string;
133 int error;
134 struct sockaddr_in address;
135 {
136 int save = errno;
137
138 if (_res.options & RES_DEBUG) {
139 fprintf(file, "res_send: %s ([%s].%u): %s\n",
140 string,
141 inet_ntoa(address.sin_addr),
142 ntohs(address.sin_port),
143 strerror(error));
144 }
145 errno = save;
146 }
147 static void
Perror(file,string,error)148 Perror(file, string, error)
149 FILE *file;
150 char *string;
151 int error;
152 {
153 int save = errno;
154
155 if (_res.options & RES_DEBUG) {
156 fprintf(file, "res_send: %s: %s\n",
157 string, strerror(error));
158 }
159 errno = save;
160 }
161 #endif
162
163 static res_send_qhook Qhook = NULL;
164 static res_send_rhook Rhook = NULL;
165
166 void
res_send_setqhook(hook)167 res_send_setqhook(hook)
168 res_send_qhook hook;
169 {
170
171 Qhook = hook;
172 }
173
174 void
res_send_setrhook(hook)175 res_send_setrhook(hook)
176 res_send_rhook hook;
177 {
178
179 Rhook = hook;
180 }
181
182 /* int
183 * res_isourserver(ina)
184 * looks up "ina" in _res.ns_addr_list[]
185 * returns:
186 * 0 : not found
187 * >0 : found
188 * author:
189 * paul vixie, 29may94
190 */
191 int
res_isourserver(inp)192 res_isourserver(inp)
193 const struct sockaddr_in *inp;
194 {
195 struct sockaddr_in ina;
196 register int ns, ret;
197
198 ina = *inp;
199 ret = 0;
200 for (ns = 0; ns < _res.nscount; ns++) {
201 register const struct sockaddr_in *srv = &_res.nsaddr_list[ns];
202
203 if (srv->sin_family == ina.sin_family &&
204 srv->sin_port == ina.sin_port &&
205 (srv->sin_addr.s_addr == INADDR_ANY ||
206 srv->sin_addr.s_addr == ina.sin_addr.s_addr)) {
207 ret++;
208 break;
209 }
210 }
211 return (ret);
212 }
213
214 /* int
215 * res_nameinquery(name, type, class, buf, eom)
216 * look for (name,type,class) in the query section of packet (buf,eom)
217 * returns:
218 * -1 : format error
219 * 0 : not found
220 * >0 : found
221 * author:
222 * paul vixie, 29may94
223 */
224 int
res_nameinquery(name,type,class,buf,eom)225 res_nameinquery(name, type, class, buf, eom)
226 const char *name;
227 register int type, class;
228 const u_char *buf, *eom;
229 {
230 register const u_char *cp = buf + HFIXEDSZ;
231 int qdcount = ntohs(((HEADER*)buf)->qdcount);
232
233 while (qdcount-- > 0) {
234 char tname[MAXDNAME+1];
235 register int n, ttype, tclass;
236
237 n = dn_expand(buf, eom, cp, tname, sizeof tname);
238 if (n < 0)
239 return (-1);
240 cp += n;
241 ttype = _getshort(cp); cp += INT16SZ;
242 tclass = _getshort(cp); cp += INT16SZ;
243 if (ttype == type &&
244 tclass == class &&
245 strcasecmp(tname, name) == 0)
246 return (1);
247 }
248 return (0);
249 }
250
251 /* int
252 * res_queriesmatch(buf1, eom1, buf2, eom2)
253 * is there a 1:1 mapping of (name,type,class)
254 * in (buf1,eom1) and (buf2,eom2)?
255 * returns:
256 * -1 : format error
257 * 0 : not a 1:1 mapping
258 * >0 : is a 1:1 mapping
259 * author:
260 * paul vixie, 29may94
261 */
262 int
res_queriesmatch(buf1,eom1,buf2,eom2)263 res_queriesmatch(buf1, eom1, buf2, eom2)
264 const u_char *buf1, *eom1;
265 const u_char *buf2, *eom2;
266 {
267 register const u_char *cp = buf1 + HFIXEDSZ;
268 int qdcount = ntohs(((HEADER*)buf1)->qdcount);
269
270 if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
271 return (0);
272 while (qdcount-- > 0) {
273 char tname[MAXDNAME+1];
274 register int n, ttype, tclass;
275
276 n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
277 if (n < 0)
278 return (-1);
279 cp += n;
280 ttype = _getshort(cp); cp += INT16SZ;
281 tclass = _getshort(cp); cp += INT16SZ;
282 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
283 return (0);
284 }
285 return (1);
286 }
287
288 int
res_send(buf,buflen,ans,anssiz)289 res_send(buf, buflen, ans, anssiz)
290 const u_char *buf;
291 int buflen;
292 u_char *ans;
293 int anssiz;
294 {
295 HEADER *hp = (HEADER *) buf;
296 HEADER *anhp = (HEADER *) ans;
297 int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns;
298 register int n;
299 u_int badns; /* XXX NSMAX can't exceed #/bits in this var */
300
301 if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
302 /* errno should have been set by res_init() in this case. */
303 return (-1);
304 }
305 DprintQ((_res.options & RES_DEBUG) || (_res.pfcode & RES_PRF_QUERY),
306 (stdout, ";; res_send()\n"), buf, buflen);
307 v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
308 gotsomewhere = 0;
309 connreset = 0;
310 terrno = ETIMEDOUT;
311 badns = 0;
312
313 /*
314 * Send request, RETRY times, or until successful
315 */
316 for (try = 0; try < _res.retry; try++) {
317 for (ns = 0; ns < _res.nscount; ns++) {
318 struct sockaddr_in *nsap = &_res.nsaddr_list[ns];
319 same_ns:
320 if (badns & (1 << ns)) {
321 res_close();
322 goto next_ns;
323 }
324
325 if (Qhook) {
326 int done = 0, loops = 0;
327
328 do {
329 res_sendhookact act;
330
331 act = (*Qhook)(&nsap, &buf, &buflen,
332 ans, anssiz, &resplen);
333 switch (act) {
334 case res_goahead:
335 done = 1;
336 break;
337 case res_nextns:
338 res_close();
339 goto next_ns;
340 case res_done:
341 return (resplen);
342 case res_modified:
343 /* give the hook another try */
344 if (++loops < 42) /*doug adams*/
345 break;
346 /*FALLTHROUGH*/
347 case res_error:
348 /*FALLTHROUGH*/
349 default:
350 return (-1);
351 }
352 } while (!done);
353 }
354
355 Dprint(_res.options & RES_DEBUG,
356 (stdout, ";; Querying server (# %d) address = %s\n",
357 ns + 1, inet_ntoa(nsap->sin_addr)));
358
359 if (v_circuit) {
360 int truncated;
361 struct iovec iov[2];
362 u_short len;
363 u_char *cp;
364
365 /*
366 * Use virtual circuit;
367 * at most one attempt per server.
368 */
369 try = _res.retry;
370 truncated = 0;
371 if ((s < 0) || (!vc)) {
372 if (s >= 0)
373 res_close();
374
375 s = socket(PF_INET, SOCK_STREAM, 0);
376 if (s < 0) {
377 terrno = errno;
378 Perror(stderr, "socket(vc)", errno);
379 return (-1);
380 }
381 errno = 0;
382 if (connect(s, (struct sockaddr *)nsap,
383 sizeof(struct sockaddr)) < 0) {
384 terrno = errno;
385 Aerror(stderr, "connect/vc",
386 errno, *nsap);
387 badns |= (1 << ns);
388 res_close();
389 goto next_ns;
390 }
391 vc = 1;
392 }
393 /*
394 * Send length & message
395 */
396 putshort((u_short)buflen, (u_char*)&len);
397 iov[0].iov_base = (caddr_t)&len;
398 iov[0].iov_len = INT16SZ;
399 iov[1].iov_base = (caddr_t)buf;
400 iov[1].iov_len = buflen;
401 if (writev(s, iov, 2) != (INT16SZ + buflen)) {
402 terrno = errno;
403 Perror(stderr, "write failed", errno);
404 badns |= (1 << ns);
405 res_close();
406 goto next_ns;
407 }
408 /*
409 * Receive length & response
410 */
411 read_len:
412 cp = ans;
413 len = INT16SZ;
414 while ((n = read(s, (char *)cp, (int)len)) > 0) {
415 cp += n;
416 if ((len -= n) <= 0)
417 break;
418 }
419 if (n <= 0) {
420 terrno = errno;
421 Perror(stderr, "read failed", errno);
422 res_close();
423 /*
424 * A long running process might get its TCP
425 * connection reset if the remote server was
426 * restarted. Requery the server instead of
427 * trying a new one. When there is only one
428 * server, this means that a query might work
429 * instead of failing. We only allow one reset
430 * per query to prevent looping.
431 */
432 if (terrno == ECONNRESET && !connreset) {
433 connreset = 1;
434 res_close();
435 goto same_ns;
436 }
437 res_close();
438 goto next_ns;
439 }
440 resplen = _getshort(ans);
441 if (resplen > anssiz) {
442 Dprint(_res.options & RES_DEBUG,
443 (stdout, ";; response truncated\n")
444 );
445 truncated = 1;
446 len = anssiz;
447 } else
448 len = resplen;
449 cp = ans;
450 while (len != 0 &&
451 (n = read(s, (char *)cp, (int)len)) > 0) {
452 cp += n;
453 len -= n;
454 }
455 if (n <= 0) {
456 terrno = errno;
457 Perror(stderr, "read(vc)", errno);
458 res_close();
459 goto next_ns;
460 }
461 if (truncated) {
462 /*
463 * Flush rest of answer
464 * so connection stays in synch.
465 */
466 anhp->tc = 1;
467 len = resplen - anssiz;
468 while (len != 0) {
469 char junk[PACKETSZ];
470
471 n = (len > sizeof(junk)
472 ? sizeof(junk)
473 : len);
474 if ((n = read(s, junk, n)) > 0)
475 len -= n;
476 else
477 break;
478 }
479 }
480 /*
481 * The calling applicating has bailed out of
482 * a previous call and failed to arrange to have
483 * the circuit closed or the server has got
484 * itself confused. Anyway drop the packet and
485 * wait for the correct one.
486 */
487 if (hp->id != anhp->id) {
488 DprintQ((_res.options & RES_DEBUG) ||
489 (_res.pfcode & RES_PRF_REPLY),
490 (stdout, ";; old answer (unexpected):\n"),
491 ans, (resplen>anssiz)?anssiz:resplen);
492 goto read_len;
493 }
494 } else {
495 /*
496 * Use datagrams.
497 */
498 struct timeval timeout;
499 fd_set dsmask;
500 struct sockaddr_in from;
501 int fromlen;
502
503 if ((s < 0) || vc) {
504 if (vc)
505 res_close();
506 s = socket(PF_INET, SOCK_DGRAM, 0);
507 if (s < 0) {
508 #if !CAN_RECONNECT
509 bad_dg_sock:
510 #endif
511 terrno = errno;
512 Perror(stderr, "socket(dg)", errno);
513 return (-1);
514 }
515 connected = 0;
516 }
517 /*
518 * On a 4.3BSD+ machine (client and server,
519 * actually), sending to a nameserver datagram
520 * port with no nameserver will cause an
521 * ICMP port unreachable message to be returned.
522 * If our datagram socket is "connected" to the
523 * server, we get an ECONNREFUSED error on the next
524 * socket operation, and select returns if the
525 * error message is received. We can thus detect
526 * the absence of a nameserver without timing out.
527 * If we have sent queries to at least two servers,
528 * however, we don't want to remain connected,
529 * as we wish to receive answers from the first
530 * server to respond.
531 */
532 if (_res.nscount == 1 || (try == 0 && ns == 0)) {
533 /*
534 * Connect only if we are sure we won't
535 * receive a response from another server.
536 */
537 if (!connected) {
538 if (connect(s, (struct sockaddr *)nsap,
539 sizeof(struct sockaddr)
540 ) < 0) {
541 Aerror(stderr,
542 "connect(dg)",
543 errno, *nsap);
544 badns |= (1 << ns);
545 res_close();
546 goto next_ns;
547 }
548 connected = 1;
549 }
550 if (send(s, (char*)buf, buflen, 0) != buflen) {
551 Perror(stderr, "send", errno);
552 badns |= (1 << ns);
553 res_close();
554 goto next_ns;
555 }
556 } else {
557 /*
558 * Disconnect if we want to listen
559 * for responses from more than one server.
560 */
561 if (connected) {
562 #if CAN_RECONNECT
563 struct sockaddr_in no_addr;
564
565 no_addr.sin_family = AF_INET;
566 no_addr.sin_addr.s_addr = INADDR_ANY;
567 no_addr.sin_port = 0;
568 (void) connect(s,
569 (struct sockaddr *)
570 &no_addr,
571 sizeof(no_addr));
572 #else
573 int s1 = socket(PF_INET, SOCK_DGRAM,0);
574 if (s1 < 0)
575 goto bad_dg_sock;
576 (void) dup2(s1, s);
577 (void) close(s1);
578 Dprint(_res.options & RES_DEBUG,
579 (stdout, ";; new DG socket\n"))
580 #endif
581 connected = 0;
582 errno = 0;
583 }
584 if (sendto(s, (char*)buf, buflen, 0,
585 (struct sockaddr *)nsap,
586 sizeof(struct sockaddr))
587 != buflen) {
588 Aerror(stderr, "sendto", errno, *nsap);
589 badns |= (1 << ns);
590 res_close();
591 goto next_ns;
592 }
593 }
594
595 /*
596 * Wait for reply
597 */
598 timeout.tv_sec = (_res.retrans << try);
599 if (try > 0)
600 timeout.tv_sec /= _res.nscount;
601 if ((long) timeout.tv_sec <= 0)
602 timeout.tv_sec = 1;
603 timeout.tv_usec = 0;
604 if (s+1 > FD_SETSIZE) {
605 Perror(stderr, "s+1 > FD_SETSIZE", EMFILE);
606 res_close();
607 goto next_ns;
608 }
609 wait:
610 FD_ZERO(&dsmask);
611 FD_SET(s, &dsmask);
612 n = select(s+1, &dsmask, (fd_set *)NULL,
613 (fd_set *)NULL, &timeout);
614 if (n < 0) {
615 if (errno == EINTR)
616 goto wait;
617 Perror(stderr, "select", errno);
618 res_close();
619 goto next_ns;
620 }
621 if (n == 0) {
622 /*
623 * timeout
624 */
625 Dprint(_res.options & RES_DEBUG,
626 (stdout, ";; timeout\n"));
627 gotsomewhere = 1;
628 res_close();
629 goto next_ns;
630 }
631 errno = 0;
632 fromlen = sizeof(struct sockaddr_in);
633 resplen = recvfrom(s, (char*)ans, anssiz, 0,
634 (struct sockaddr *)&from, &fromlen);
635 if (resplen <= 0) {
636 Perror(stderr, "recvfrom", errno);
637 res_close();
638 goto next_ns;
639 }
640 gotsomewhere = 1;
641 if (hp->id != anhp->id) {
642 /*
643 * response from old query, ignore it.
644 * XXX - potential security hazard could
645 * be detected here.
646 */
647 DprintQ((_res.options & RES_DEBUG) ||
648 (_res.pfcode & RES_PRF_REPLY),
649 (stdout, ";; old answer:\n"),
650 ans, (resplen>anssiz)?anssiz:resplen);
651 goto wait;
652 }
653 #if CHECK_SRVR_ADDR
654 if (!(_res.options & RES_INSECURE1) &&
655 !res_isourserver(&from)) {
656 /*
657 * response from wrong server? ignore it.
658 * XXX - potential security hazard could
659 * be detected here.
660 */
661 DprintQ((_res.options & RES_DEBUG) ||
662 (_res.pfcode & RES_PRF_REPLY),
663 (stdout, ";; not our server:\n"),
664 ans, (resplen>anssiz)?anssiz:resplen);
665 goto wait;
666 }
667 #endif
668 if (!(_res.options & RES_INSECURE2) &&
669 !res_queriesmatch(buf, buf + buflen,
670 ans, ans + anssiz)) {
671 /*
672 * response contains wrong query? ignore it.
673 * XXX - potential security hazard could
674 * be detected here.
675 */
676 DprintQ((_res.options & RES_DEBUG) ||
677 (_res.pfcode & RES_PRF_REPLY),
678 (stdout, ";; wrong query name:\n"),
679 ans, (resplen>anssiz)?anssiz:resplen);
680 goto wait;
681 }
682 if (anhp->rcode == SERVFAIL ||
683 anhp->rcode == NOTIMP ||
684 anhp->rcode == REFUSED) {
685 DprintQ(_res.options & RES_DEBUG,
686 (stdout, "server rejected query:\n"),
687 ans, (resplen>anssiz)?anssiz:resplen);
688 badns |= (1 << ns);
689 res_close();
690 /* don't retry if called from dig */
691 if (!_res.pfcode)
692 goto next_ns;
693 }
694 if (!(_res.options & RES_IGNTC) && anhp->tc) {
695 /*
696 * get rest of answer;
697 * use TCP with same server.
698 */
699 Dprint(_res.options & RES_DEBUG,
700 (stdout, ";; truncated answer\n"));
701 v_circuit = 1;
702 res_close();
703 goto same_ns;
704 }
705 } /*if vc/dg*/
706 Dprint((_res.options & RES_DEBUG) ||
707 ((_res.pfcode & RES_PRF_REPLY) &&
708 (_res.pfcode & RES_PRF_HEAD1)),
709 (stdout, ";; got answer:\n"));
710 DprintQ((_res.options & RES_DEBUG) ||
711 (_res.pfcode & RES_PRF_REPLY),
712 (stdout, ""),
713 ans, (resplen>anssiz)?anssiz:resplen);
714 /*
715 * If using virtual circuits, we assume that the first server
716 * is preferred over the rest (i.e. it is on the local
717 * machine) and only keep that one open.
718 * If we have temporarily opened a virtual circuit,
719 * or if we haven't been asked to keep a socket open,
720 * close the socket.
721 */
722 if ((v_circuit && (!(_res.options & RES_USEVC) || ns != 0)) ||
723 !(_res.options & RES_STAYOPEN)) {
724 res_close();
725 }
726 if (Rhook) {
727 int done = 0, loops = 0;
728
729 do {
730 res_sendhookact act;
731
732 act = (*Rhook)(nsap, buf, buflen,
733 ans, anssiz, &resplen);
734 switch (act) {
735 case res_goahead:
736 case res_done:
737 done = 1;
738 break;
739 case res_nextns:
740 res_close();
741 goto next_ns;
742 case res_modified:
743 /* give the hook another try */
744 if (++loops < 42) /*doug adams*/
745 break;
746 /*FALLTHROUGH*/
747 case res_error:
748 /*FALLTHROUGH*/
749 default:
750 return (-1);
751 }
752 } while (!done);
753
754 }
755 return (resplen);
756 next_ns: ;
757 } /*foreach ns*/
758 } /*foreach retry*/
759 res_close();
760 if (!v_circuit)
761 if (!gotsomewhere)
762 errno = ECONNREFUSED; /* no nameservers found */
763 else
764 errno = ETIMEDOUT; /* no answer obtained */
765 else
766 errno = terrno;
767 return (-1);
768 }
769
770 /*
771 * This routine is for closing the socket if a virtual circuit is used and
772 * the program wants to close it. This provides support for endhostent()
773 * which expects to close the socket.
774 *
775 * This routine is not expected to be user visible.
776 */
777 void
res_close()778 res_close()
779 {
780 if (s >= 0) {
781 (void) close(s);
782 s = -1;
783 connected = 0;
784 vc = 0;
785 }
786 }
787
788 #ifdef ultrix
789 /* ultrix 4.0 had some icky packaging in its libc.a. alias for it here.
790 * there is more gunk of this kind over in res_debug.c.
791 */
792
793 void
_res_close()794 _res_close()
795 {
796 res_close();
797 }
798
799 #undef res_send
800 int
res_send(buf,buflen,ans,anssiz)801 res_send(buf, buflen, ans, anssiz)
802 const u_char *buf;
803 int buflen;
804 u_char *ans;
805 int anssiz;
806 {
807 return (__res_send(buf, buflen, ans, anssiz));
808 }
809 #endif /* Ultrix 4.0 hackery */
810