Annotation of src/lib/libc/resolv/res_send.c, Revision 1.15
1.15 ! christos 1: /* $NetBSD: res_send.c,v 1.14 2008/06/21 20:41:48 christos Exp $ */
1.1 christos 2:
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:
36: /*
37: * Portions Copyright (c) 1993 by Digital Equipment Corporation.
38: *
39: * Permission to use, copy, modify, and distribute this software for any
40: * purpose with or without fee is hereby granted, provided that the above
41: * copyright notice and this permission notice appear in all copies, and that
42: * the name of Digital Equipment Corporation not be used in advertising or
43: * publicity pertaining to distribution of the document or software without
44: * specific, written prior permission.
45: *
46: * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
47: * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
48: * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
49: * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
50: * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
51: * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
52: * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
53: * SOFTWARE.
54: */
55:
56: /*
1.10 christos 57: * Copyright (c) 2005 by Internet Systems Consortium, Inc. ("ISC")
1.1 christos 58: * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
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.
63: *
64: * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
65: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
66: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
67: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
68: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
69: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
70: * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
71: */
72:
1.4 christos 73: #include <sys/cdefs.h>
1.1 christos 74: #if defined(LIBC_SCCS) && !defined(lint)
1.4 christos 75: #ifdef notdef
1.1 christos 76: static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
1.14 christos 77: static const char rcsid[] = "Id: res_send.c,v 1.18.10.1 2008/01/27 02:06:46 marka Exp";
1.4 christos 78: #else
1.15 ! christos 79: __RCSID("$NetBSD: res_send.c,v 1.14 2008/06/21 20:41:48 christos Exp $");
1.4 christos 80: #endif
1.1 christos 81: #endif /* LIBC_SCCS and not lint */
82:
1.10 christos 83: /*! \file
84: * \brief
1.1 christos 85: * Send query to name server and wait for reply.
86: */
87:
1.8 kleink 88: #include "namespace.h"
1.1 christos 89: #include "port_before.h"
90: #include "fd_setsize.h"
91:
92: #include <sys/types.h>
93: #include <sys/param.h>
94: #include <sys/time.h>
95: #include <sys/socket.h>
96: #include <sys/uio.h>
97:
98: #include <netinet/in.h>
99: #include <arpa/nameser.h>
100: #include <arpa/inet.h>
101:
102: #include <errno.h>
103: #include <netdb.h>
104: #include <resolv.h>
105: #include <signal.h>
106: #include <stdio.h>
107: #include <stdlib.h>
108: #include <string.h>
109: #include <unistd.h>
110:
111: #include <isc/eventlib.h>
112:
113: #include "port_after.h"
114:
1.6 christos 115: #if 0
1.5 christos 116: #ifdef __weak_alias
117: __weak_alias(res_ourserver_p,__res_ourserver_p)
118: __weak_alias(res_nameinquery,__res_nameinquery)
119: __weak_alias(res_queriesmatch,__res_queriesmatch)
120: __weak_alias(res_nsend,__res_nsend)
121: #endif
1.6 christos 122: #endif
1.5 christos 123:
1.10 christos 124:
125: #ifdef USE_POLL
126: #ifdef HAVE_STROPTS_H
127: #include <stropts.h>
128: #endif
129: #include <poll.h>
130: #endif /* USE_POLL */
131:
1.1 christos 132: /* Options. Leave them on. */
1.15 ! christos 133: #ifndef DEBUG
1.1 christos 134: #define DEBUG
1.15 ! christos 135: #endif
1.1 christos 136: #include "res_debug.h"
137: #include "res_private.h"
138:
139: #define EXT(res) ((res)->_u._ext)
140:
1.10 christos 141: #ifndef USE_POLL
1.1 christos 142: static const int highestFD = FD_SETSIZE - 1;
1.14 christos 143: #else
144: static int highestFD = 0;
1.10 christos 145: #endif
1.1 christos 146:
147: /* Forward. */
148:
149: static int get_salen __P((const struct sockaddr *));
150: static struct sockaddr * get_nsaddr __P((res_state, size_t));
151: static int send_vc(res_state, const u_char *, int,
152: u_char *, int, int *, int);
153: static int send_dg(res_state, const u_char *, int,
1.10 christos 154: u_char *, int, int *, int, int,
1.1 christos 155: int *, int *);
156: static void Aerror(const res_state, FILE *, const char *, int,
157: const struct sockaddr *, int);
158: static void Perror(const res_state, FILE *, const char *, int);
159: static int sock_eq(struct sockaddr *, struct sockaddr *);
1.10 christos 160: #if defined(NEED_PSELECT) && !defined(USE_POLL)
1.1 christos 161: static int pselect(int, void *, void *, void *,
162: struct timespec *,
163: const sigset_t *);
164: #endif
165: void res_pquery(const res_state, const u_char *, int, FILE *);
166:
167: static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
168:
169: /* Public. */
170:
1.10 christos 171: /*%
1.1 christos 172: * looks up "ina" in _res.ns_addr_list[]
1.10 christos 173: *
1.1 christos 174: * returns:
1.10 christos 175: *\li 0 : not found
176: *\li >0 : found
177: *
1.1 christos 178: * author:
1.10 christos 179: *\li paul vixie, 29may94
1.1 christos 180: */
181: int
182: res_ourserver_p(const res_state statp, const struct sockaddr *sa) {
183: const struct sockaddr_in *inp, *srv;
184: const struct sockaddr_in6 *in6p, *srv6;
185: int ns;
186:
187: switch (sa->sa_family) {
188: case AF_INET:
1.3 christos 189: inp = (const struct sockaddr_in *)(const void *)sa;
1.1 christos 190: for (ns = 0; ns < statp->nscount; ns++) {
1.2 christos 191: srv = (struct sockaddr_in *)(void *)get_nsaddr(statp, (size_t)ns);
1.1 christos 192: if (srv->sin_family == inp->sin_family &&
193: srv->sin_port == inp->sin_port &&
194: (srv->sin_addr.s_addr == INADDR_ANY ||
195: srv->sin_addr.s_addr == inp->sin_addr.s_addr))
196: return (1);
197: }
198: break;
199: case AF_INET6:
200: if (EXT(statp).ext == NULL)
201: break;
1.3 christos 202: in6p = (const struct sockaddr_in6 *)(const void *)sa;
1.1 christos 203: for (ns = 0; ns < statp->nscount; ns++) {
1.2 christos 204: srv6 = (struct sockaddr_in6 *)(void *)get_nsaddr(statp, (size_t)ns);
1.1 christos 205: if (srv6->sin6_family == in6p->sin6_family &&
206: srv6->sin6_port == in6p->sin6_port &&
207: #ifdef HAVE_SIN6_SCOPE_ID
1.7 christos 208: (srv6->sin6_scope_id == 0 ||
209: srv6->sin6_scope_id == in6p->sin6_scope_id) &&
1.1 christos 210: #endif
211: (IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) ||
212: IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr)))
213: return (1);
214: }
215: break;
216: default:
217: break;
218: }
219: return (0);
220: }
221:
1.10 christos 222: /*%
1.1 christos 223: * look for (name,type,class) in the query section of packet (buf,eom)
1.10 christos 224: *
1.1 christos 225: * requires:
1.10 christos 226: *\li buf + HFIXEDSZ <= eom
227: *
1.1 christos 228: * returns:
1.10 christos 229: *\li -1 : format error
230: *\li 0 : not found
231: *\li >0 : found
232: *
1.1 christos 233: * author:
1.10 christos 234: *\li paul vixie, 29may94
1.1 christos 235: */
236: int
237: res_nameinquery(const char *name, int type, int class,
238: const u_char *buf, const u_char *eom)
239: {
240: const u_char *cp = buf + HFIXEDSZ;
1.2 christos 241: int qdcount = ntohs(((const HEADER*)(const void *)buf)->qdcount);
1.1 christos 242:
243: while (qdcount-- > 0) {
244: char tname[MAXDNAME+1];
245: int n, ttype, tclass;
246:
247: n = dn_expand(buf, eom, cp, tname, sizeof tname);
248: if (n < 0)
249: return (-1);
250: cp += n;
251: if (cp + 2 * INT16SZ > eom)
252: return (-1);
253: ttype = ns_get16(cp); cp += INT16SZ;
254: tclass = ns_get16(cp); cp += INT16SZ;
255: if (ttype == type && tclass == class &&
256: ns_samename(tname, name) == 1)
257: return (1);
258: }
259: return (0);
260: }
261:
1.10 christos 262: /*%
1.1 christos 263: * is there a 1:1 mapping of (name,type,class)
264: * in (buf1,eom1) and (buf2,eom2)?
1.10 christos 265: *
1.1 christos 266: * returns:
1.10 christos 267: *\li -1 : format error
268: *\li 0 : not a 1:1 mapping
269: *\li >0 : is a 1:1 mapping
270: *
1.1 christos 271: * author:
1.10 christos 272: *\li paul vixie, 29may94
1.1 christos 273: */
274: int
275: res_queriesmatch(const u_char *buf1, const u_char *eom1,
276: const u_char *buf2, const u_char *eom2)
277: {
278: const u_char *cp = buf1 + HFIXEDSZ;
1.2 christos 279: int qdcount = ntohs(((const HEADER*)(const void *)buf1)->qdcount);
1.1 christos 280:
281: if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
282: return (-1);
283:
284: /*
285: * Only header section present in replies to
286: * dynamic update packets.
287: */
1.2 christos 288: if ((((const HEADER *)(const void *)buf1)->opcode == ns_o_update) &&
289: (((const HEADER *)(const void *)buf2)->opcode == ns_o_update))
1.1 christos 290: return (1);
291:
1.2 christos 292: if (qdcount != ntohs(((const HEADER*)(const void *)buf2)->qdcount))
1.1 christos 293: return (0);
294: while (qdcount-- > 0) {
295: char tname[MAXDNAME+1];
296: int n, ttype, tclass;
297:
298: n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
299: if (n < 0)
300: return (-1);
301: cp += n;
302: if (cp + 2 * INT16SZ > eom1)
303: return (-1);
304: ttype = ns_get16(cp); cp += INT16SZ;
305: tclass = ns_get16(cp); cp += INT16SZ;
306: if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
307: return (0);
308: }
309: return (1);
310: }
311:
312: int
313: res_nsend(res_state statp,
314: const u_char *buf, int buflen, u_char *ans, int anssiz)
315: {
1.14 christos 316: int gotsomewhere, terrno, tries, v_circuit, resplen, ns, n;
1.1 christos 317: char abuf[NI_MAXHOST];
318:
1.14 christos 319: #ifdef USE_POLL
320: highestFD = sysconf(_SC_OPEN_MAX) - 1;
321: #endif
322:
1.10 christos 323: /* No name servers or res_init() failure */
324: if (statp->nscount == 0 || EXT(statp).ext == NULL) {
1.1 christos 325: errno = ESRCH;
326: return (-1);
327: }
328: if (anssiz < HFIXEDSZ) {
329: errno = EINVAL;
330: return (-1);
331: }
332: DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY),
333: (stdout, ";; res_send()\n"), buf, buflen);
334: v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ;
335: gotsomewhere = 0;
336: terrno = ETIMEDOUT;
337:
338: /*
339: * If the ns_addr_list in the resolver context has changed, then
340: * invalidate our cached copy and the associated timing data.
341: */
342: if (EXT(statp).nscount != 0) {
343: int needclose = 0;
344: struct sockaddr_storage peer;
345: ISC_SOCKLEN_T peerlen;
346:
347: if (EXT(statp).nscount != statp->nscount)
348: needclose++;
349: else
350: for (ns = 0; ns < statp->nscount; ns++) {
351: if (statp->nsaddr_list[ns].sin_family &&
1.2 christos 352: !sock_eq((struct sockaddr *)(void *)&statp->nsaddr_list[ns],
353: (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[ns])) {
1.1 christos 354: needclose++;
355: break;
356: }
357:
358: if (EXT(statp).nssocks[ns] == -1)
359: continue;
360: peerlen = sizeof(peer);
361: if (getsockname(EXT(statp).nssocks[ns],
1.2 christos 362: (struct sockaddr *)(void *)&peer, &peerlen) < 0) {
1.1 christos 363: needclose++;
364: break;
365: }
1.2 christos 366: if (!sock_eq((struct sockaddr *)(void *)&peer,
367: get_nsaddr(statp, (size_t)ns))) {
1.1 christos 368: needclose++;
369: break;
370: }
371: }
372: if (needclose) {
373: res_nclose(statp);
374: EXT(statp).nscount = 0;
375: }
376: }
377:
378: /*
379: * Maybe initialize our private copy of the ns_addr_list.
380: */
381: if (EXT(statp).nscount == 0) {
382: for (ns = 0; ns < statp->nscount; ns++) {
383: EXT(statp).nstimes[ns] = RES_MAXTIME;
384: EXT(statp).nssocks[ns] = -1;
385: if (!statp->nsaddr_list[ns].sin_family)
386: continue;
387: EXT(statp).ext->nsaddrs[ns].sin =
388: statp->nsaddr_list[ns];
389: }
390: EXT(statp).nscount = statp->nscount;
391: }
392:
393: /*
394: * Some resolvers want to even out the load on their nameservers.
395: * Note that RES_BLAST overrides RES_ROTATE.
396: */
397: if ((statp->options & RES_ROTATE) != 0U &&
398: (statp->options & RES_BLAST) == 0U) {
399: union res_sockaddr_union inu;
400: struct sockaddr_in ina;
401: int lastns = statp->nscount - 1;
402: int fd;
403: u_int16_t nstime;
404:
405: if (EXT(statp).ext != NULL)
406: inu = EXT(statp).ext->nsaddrs[0];
407: ina = statp->nsaddr_list[0];
408: fd = EXT(statp).nssocks[0];
409: nstime = EXT(statp).nstimes[0];
410: for (ns = 0; ns < lastns; ns++) {
411: if (EXT(statp).ext != NULL)
412: EXT(statp).ext->nsaddrs[ns] =
413: EXT(statp).ext->nsaddrs[ns + 1];
414: statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1];
415: EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1];
416: EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1];
417: }
418: if (EXT(statp).ext != NULL)
419: EXT(statp).ext->nsaddrs[lastns] = inu;
420: statp->nsaddr_list[lastns] = ina;
421: EXT(statp).nssocks[lastns] = fd;
422: EXT(statp).nstimes[lastns] = nstime;
423: }
424:
425: /*
426: * Send request, RETRY times, or until successful.
427: */
1.14 christos 428: for (tries = 0; tries < statp->retry; tries++) {
1.1 christos 429: for (ns = 0; ns < statp->nscount; ns++) {
430: struct sockaddr *nsap;
431: int nsaplen;
1.2 christos 432: nsap = get_nsaddr(statp, (size_t)ns);
1.1 christos 433: nsaplen = get_salen(nsap);
434: statp->_flags &= ~RES_F_LASTMASK;
435: statp->_flags |= (ns << RES_F_LASTSHIFT);
436: same_ns:
437: if (statp->qhook) {
438: int done = 0, loops = 0;
439:
440: do {
441: res_sendhookact act;
442:
443: act = (*statp->qhook)(&nsap, &buf, &buflen,
444: ans, anssiz, &resplen);
445: switch (act) {
446: case res_goahead:
447: done = 1;
448: break;
449: case res_nextns:
450: res_nclose(statp);
451: goto next_ns;
452: case res_done:
453: return (resplen);
454: case res_modified:
455: /* give the hook another try */
456: if (++loops < 42) /*doug adams*/
457: break;
458: /*FALLTHROUGH*/
459: case res_error:
460: /*FALLTHROUGH*/
461: default:
462: goto fail;
463: }
464: } while (!done);
465: }
466:
467: Dprint(((statp->options & RES_DEBUG) &&
1.2 christos 468: getnameinfo(nsap, (socklen_t)nsaplen, abuf, sizeof(abuf),
1.1 christos 469: NULL, 0, niflags) == 0),
470: (stdout, ";; Querying server (# %d) address = %s\n",
471: ns + 1, abuf));
472:
473:
474: if (v_circuit) {
475: /* Use VC; at most one attempt per server. */
1.14 christos 476: tries = statp->retry;
1.1 christos 477: n = send_vc(statp, buf, buflen, ans, anssiz, &terrno,
478: ns);
479: if (n < 0)
480: goto fail;
481: if (n == 0)
482: goto next_ns;
483: resplen = n;
484: } else {
485: /* Use datagrams. */
486: n = send_dg(statp, buf, buflen, ans, anssiz, &terrno,
1.14 christos 487: ns, tries, &v_circuit, &gotsomewhere);
1.1 christos 488: if (n < 0)
489: goto fail;
490: if (n == 0)
491: goto next_ns;
492: if (v_circuit)
493: goto same_ns;
494: resplen = n;
495: }
496:
497: Dprint((statp->options & RES_DEBUG) ||
498: ((statp->pfcode & RES_PRF_REPLY) &&
499: (statp->pfcode & RES_PRF_HEAD1)),
500: (stdout, ";; got answer:\n"));
501:
502: DprintQ((statp->options & RES_DEBUG) ||
503: (statp->pfcode & RES_PRF_REPLY),
504: (stdout, "%s", ""),
505: ans, (resplen > anssiz) ? anssiz : resplen);
506:
507: /*
508: * If we have temporarily opened a virtual circuit,
509: * or if we haven't been asked to keep a socket open,
510: * close the socket.
511: */
512: if ((v_circuit && (statp->options & RES_USEVC) == 0U) ||
513: (statp->options & RES_STAYOPEN) == 0U) {
514: res_nclose(statp);
515: }
516: if (statp->rhook) {
517: int done = 0, loops = 0;
518:
519: do {
520: res_sendhookact act;
521:
522: act = (*statp->rhook)(nsap, buf, buflen,
523: ans, anssiz, &resplen);
524: switch (act) {
525: case res_goahead:
526: case res_done:
527: done = 1;
528: break;
529: case res_nextns:
530: res_nclose(statp);
531: goto next_ns;
532: case res_modified:
533: /* give the hook another try */
534: if (++loops < 42) /*doug adams*/
535: break;
536: /*FALLTHROUGH*/
537: case res_error:
538: /*FALLTHROUGH*/
539: default:
540: goto fail;
541: }
542: } while (!done);
543:
544: }
545: return (resplen);
546: next_ns: ;
547: } /*foreach ns*/
548: } /*foreach retry*/
549: res_nclose(statp);
550: if (!v_circuit) {
551: if (!gotsomewhere)
1.10 christos 552: errno = ECONNREFUSED; /*%< no nameservers found */
1.1 christos 553: else
1.10 christos 554: errno = ETIMEDOUT; /*%< no answer obtained */
1.1 christos 555: } else
556: errno = terrno;
557: return (-1);
558: fail:
559: res_nclose(statp);
560: return (-1);
561: }
562:
563: /* Private */
564:
565: static int
566: get_salen(sa)
567: const struct sockaddr *sa;
568: {
569:
570: #ifdef HAVE_SA_LEN
571: /* There are people do not set sa_len. Be forgiving to them. */
572: if (sa->sa_len)
573: return (sa->sa_len);
574: #endif
575:
576: if (sa->sa_family == AF_INET)
577: return (sizeof(struct sockaddr_in));
578: else if (sa->sa_family == AF_INET6)
579: return (sizeof(struct sockaddr_in6));
580: else
1.10 christos 581: return (0); /*%< unknown, die on connect */
1.1 christos 582: }
583:
1.10 christos 584: /*%
1.1 christos 585: * pick appropriate nsaddr_list for use. see res_init() for initialization.
586: */
587: static struct sockaddr *
588: get_nsaddr(statp, n)
589: res_state statp;
590: size_t n;
591: {
592:
593: if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) {
594: /*
595: * - EXT(statp).ext->nsaddrs[n] holds an address that is larger
596: * than struct sockaddr, and
597: * - user code did not update statp->nsaddr_list[n].
598: */
599: return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n];
600: } else {
601: /*
602: * - user code updated statp->nsaddr_list[n], or
603: * - statp->nsaddr_list[n] has the same content as
604: * EXT(statp).ext->nsaddrs[n].
605: */
606: return (struct sockaddr *)(void *)&statp->nsaddr_list[n];
607: }
608: }
609:
610: static int
611: send_vc(res_state statp,
612: const u_char *buf, int buflen, u_char *ans, int anssiz,
613: int *terrno, int ns)
614: {
1.3 christos 615: const HEADER *hp = (const HEADER *)(const void *)buf;
616: HEADER *anhp = (HEADER *)(void *)ans;
1.1 christos 617: struct sockaddr *nsap;
618: int nsaplen;
619: int truncating, connreset, resplen, n;
620: struct iovec iov[2];
621: u_short len;
622: u_char *cp;
623: void *tmp;
1.14 christos 624: #ifdef SO_NOSIGPIPE
625: int on = 1;
626: #endif
1.1 christos 627:
1.2 christos 628: nsap = get_nsaddr(statp, (size_t)ns);
1.1 christos 629: nsaplen = get_salen(nsap);
630:
631: connreset = 0;
632: same_ns:
633: truncating = 0;
634:
635: /* Are we still talking to whom we want to talk to? */
636: if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) {
637: struct sockaddr_storage peer;
638: ISC_SOCKLEN_T size = sizeof peer;
639:
640: if (getpeername(statp->_vcsock,
1.2 christos 641: (struct sockaddr *)(void *)&peer, &size) < 0 ||
642: !sock_eq((struct sockaddr *)(void *)&peer, nsap)) {
1.1 christos 643: res_nclose(statp);
644: statp->_flags &= ~RES_F_VC;
645: }
646: }
647:
648: if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) {
649: if (statp->_vcsock >= 0)
650: res_nclose(statp);
651:
652: statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM, 0);
653: if (statp->_vcsock > highestFD) {
654: res_nclose(statp);
655: errno = ENOTSOCK;
656: }
657: if (statp->_vcsock < 0) {
658: switch (errno) {
659: case EPROTONOSUPPORT:
660: #ifdef EPFNOSUPPORT
661: case EPFNOSUPPORT:
662: #endif
663: case EAFNOSUPPORT:
664: Perror(statp, stderr, "socket(vc)", errno);
665: return (0);
666: default:
667: *terrno = errno;
668: Perror(statp, stderr, "socket(vc)", errno);
669: return (-1);
670: }
671: }
1.14 christos 672: #ifdef SO_NOSIGPIPE
673: /*
674: * Disable generation of SIGPIPE when writing to a closed
675: * socket. Write should return -1 and set errno to EPIPE
676: * instead.
677: *
678: * Push on even if setsockopt(SO_NOSIGPIPE) fails.
679: */
680: (void)setsockopt(statp->_vcsock, SOL_SOCKET, SO_NOSIGPIPE, &on,
681: sizeof(on));
682: #endif
1.1 christos 683: errno = 0;
1.2 christos 684: if (connect(statp->_vcsock, nsap, (socklen_t)nsaplen) < 0) {
1.1 christos 685: *terrno = errno;
686: Aerror(statp, stderr, "connect/vc", errno, nsap,
687: nsaplen);
688: res_nclose(statp);
689: return (0);
690: }
691: statp->_flags |= RES_F_VC;
692: }
693:
694: /*
695: * Send length & message
696: */
1.2 christos 697: ns_put16((u_short)buflen, (u_char*)(void *)&len);
1.1 christos 698: iov[0] = evConsIovec(&len, INT16SZ);
699: DE_CONST(buf, tmp);
1.2 christos 700: iov[1] = evConsIovec(tmp, (size_t)buflen);
1.1 christos 701: if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) {
702: *terrno = errno;
703: Perror(statp, stderr, "write failed", errno);
704: res_nclose(statp);
705: return (0);
706: }
707: /*
708: * Receive length & response
709: */
710: read_len:
711: cp = ans;
712: len = INT16SZ;
1.2 christos 713: while ((n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0) {
1.1 christos 714: cp += n;
1.2 christos 715: if ((len -= n) == 0)
1.1 christos 716: break;
717: }
718: if (n <= 0) {
719: *terrno = errno;
720: Perror(statp, stderr, "read failed", errno);
721: res_nclose(statp);
722: /*
723: * A long running process might get its TCP
724: * connection reset if the remote server was
725: * restarted. Requery the server instead of
726: * trying a new one. When there is only one
727: * server, this means that a query might work
728: * instead of failing. We only allow one reset
729: * per query to prevent looping.
730: */
731: if (*terrno == ECONNRESET && !connreset) {
732: connreset = 1;
733: res_nclose(statp);
734: goto same_ns;
735: }
736: res_nclose(statp);
737: return (0);
738: }
739: resplen = ns_get16(ans);
740: if (resplen > anssiz) {
741: Dprint(statp->options & RES_DEBUG,
742: (stdout, ";; response truncated\n")
743: );
744: truncating = 1;
745: len = anssiz;
746: } else
747: len = resplen;
748: if (len < HFIXEDSZ) {
749: /*
750: * Undersized message.
751: */
752: Dprint(statp->options & RES_DEBUG,
753: (stdout, ";; undersized: %d\n", len));
754: *terrno = EMSGSIZE;
755: res_nclose(statp);
756: return (0);
757: }
758: cp = ans;
1.2 christos 759: while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (size_t)len)) > 0){
1.1 christos 760: cp += n;
761: len -= n;
762: }
763: if (n <= 0) {
764: *terrno = errno;
765: Perror(statp, stderr, "read(vc)", errno);
766: res_nclose(statp);
767: return (0);
768: }
769: if (truncating) {
770: /*
771: * Flush rest of answer so connection stays in synch.
772: */
773: anhp->tc = 1;
774: len = resplen - anssiz;
775: while (len != 0) {
776: char junk[PACKETSZ];
777:
778: n = read(statp->_vcsock, junk,
779: (len > sizeof junk) ? sizeof junk : len);
780: if (n > 0)
781: len -= n;
782: else
783: break;
784: }
785: }
786: /*
787: * If the calling applicating has bailed out of
788: * a previous call and failed to arrange to have
789: * the circuit closed or the server has got
790: * itself confused, then drop the packet and
791: * wait for the correct one.
792: */
793: if (hp->id != anhp->id) {
794: DprintQ((statp->options & RES_DEBUG) ||
795: (statp->pfcode & RES_PRF_REPLY),
796: (stdout, ";; old answer (unexpected):\n"),
797: ans, (resplen > anssiz) ? anssiz: resplen);
798: goto read_len;
799: }
800:
801: /*
802: * All is well, or the error is fatal. Signal that the
803: * next nameserver ought not be tried.
804: */
805: return (resplen);
806: }
807:
808: static int
1.10 christos 809: send_dg(res_state statp, const u_char *buf, int buflen, u_char *ans,
1.14 christos 810: int anssiz, int *terrno, int ns, int tries, int *v_circuit,
1.10 christos 811: int *gotsomewhere)
1.1 christos 812: {
1.2 christos 813: const HEADER *hp = (const HEADER *)(const void *)buf;
814: HEADER *anhp = (HEADER *)(void *)ans;
1.1 christos 815: const struct sockaddr *nsap;
816: int nsaplen;
817: struct timespec now, timeout, finish;
818: struct sockaddr_storage from;
819: ISC_SOCKLEN_T fromlen;
820: int resplen, seconds, n, s;
1.10 christos 821: #ifdef USE_POLL
822: int polltimeout;
823: struct pollfd pollfd;
824: #else
825: fd_set dsmask;
826: #endif
1.1 christos 827:
1.2 christos 828: nsap = get_nsaddr(statp, (size_t)ns);
1.1 christos 829: nsaplen = get_salen(nsap);
830: if (EXT(statp).nssocks[ns] == -1) {
831: EXT(statp).nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM, 0);
832: if (EXT(statp).nssocks[ns] > highestFD) {
833: res_nclose(statp);
834: errno = ENOTSOCK;
835: }
836: if (EXT(statp).nssocks[ns] < 0) {
837: switch (errno) {
838: case EPROTONOSUPPORT:
839: #ifdef EPFNOSUPPORT
840: case EPFNOSUPPORT:
841: #endif
842: case EAFNOSUPPORT:
843: Perror(statp, stderr, "socket(dg)", errno);
844: return (0);
845: default:
846: *terrno = errno;
847: Perror(statp, stderr, "socket(dg)", errno);
848: return (-1);
849: }
850: }
851: #ifndef CANNOT_CONNECT_DGRAM
852: /*
853: * On a 4.3BSD+ machine (client and server,
854: * actually), sending to a nameserver datagram
855: * port with no nameserver will cause an
856: * ICMP port unreachable message to be returned.
857: * If our datagram socket is "connected" to the
858: * server, we get an ECONNREFUSED error on the next
859: * socket operation, and select returns if the
860: * error message is received. We can thus detect
861: * the absence of a nameserver without timing out.
862: */
1.2 christos 863: if (connect(EXT(statp).nssocks[ns], nsap, (socklen_t)nsaplen) < 0) {
1.1 christos 864: Aerror(statp, stderr, "connect(dg)", errno, nsap,
865: nsaplen);
866: res_nclose(statp);
867: return (0);
868: }
869: #endif /* !CANNOT_CONNECT_DGRAM */
870: Dprint(statp->options & RES_DEBUG,
871: (stdout, ";; new DG socket\n"))
872: }
873: s = EXT(statp).nssocks[ns];
874: #ifndef CANNOT_CONNECT_DGRAM
1.2 christos 875: if (send(s, (const char*)buf, (size_t)buflen, 0) != buflen) {
1.1 christos 876: Perror(statp, stderr, "send", errno);
877: res_nclose(statp);
878: return (0);
879: }
880: #else /* !CANNOT_CONNECT_DGRAM */
881: if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen)
882: {
883: Aerror(statp, stderr, "sendto", errno, nsap, nsaplen);
884: res_nclose(statp);
885: return (0);
886: }
887: #endif /* !CANNOT_CONNECT_DGRAM */
888:
889: /*
890: * Wait for reply.
891: */
1.14 christos 892: seconds = (statp->retrans << tries);
1.1 christos 893: if (ns > 0)
894: seconds /= statp->nscount;
895: if (seconds <= 0)
896: seconds = 1;
897: now = evNowTime();
1.3 christos 898: timeout = evConsTime((long)seconds, 0L);
1.1 christos 899: finish = evAddTime(now, timeout);
900: goto nonow;
901: wait:
902: now = evNowTime();
903: nonow:
1.10 christos 904: #ifndef USE_POLL
1.1 christos 905: FD_ZERO(&dsmask);
906: FD_SET(s, &dsmask);
907: if (evCmpTime(finish, now) > 0)
908: timeout = evSubTime(finish, now);
909: else
1.3 christos 910: timeout = evConsTime(0L, 0L);
1.1 christos 911: n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL);
1.10 christos 912: #else
913: timeout = evSubTime(finish, now);
914: if (timeout.tv_sec < 0)
1.11 christos 915: timeout = evConsTime(0L, 0L);
1.10 christos 916: polltimeout = 1000*timeout.tv_sec +
917: timeout.tv_nsec/1000000;
918: pollfd.fd = s;
919: pollfd.events = POLLRDNORM;
920: n = poll(&pollfd, 1, polltimeout);
921: #endif /* USE_POLL */
922:
1.1 christos 923: if (n == 0) {
924: Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n"));
925: *gotsomewhere = 1;
926: return (0);
927: }
928: if (n < 0) {
929: if (errno == EINTR)
930: goto wait;
1.10 christos 931: #ifndef USE_POLL
1.1 christos 932: Perror(statp, stderr, "select", errno);
1.10 christos 933: #else
934: Perror(statp, stderr, "poll", errno);
935: #endif /* USE_POLL */
1.1 christos 936: res_nclose(statp);
937: return (0);
938: }
939: errno = 0;
940: fromlen = sizeof(from);
1.2 christos 941: resplen = recvfrom(s, (char*)ans, (size_t)anssiz,0,
942: (struct sockaddr *)(void *)&from, &fromlen);
1.1 christos 943: if (resplen <= 0) {
944: Perror(statp, stderr, "recvfrom", errno);
945: res_nclose(statp);
946: return (0);
947: }
948: *gotsomewhere = 1;
949: if (resplen < HFIXEDSZ) {
950: /*
951: * Undersized message.
952: */
953: Dprint(statp->options & RES_DEBUG,
954: (stdout, ";; undersized: %d\n",
955: resplen));
956: *terrno = EMSGSIZE;
957: res_nclose(statp);
958: return (0);
959: }
960: if (hp->id != anhp->id) {
961: /*
962: * response from old query, ignore it.
963: * XXX - potential security hazard could
964: * be detected here.
965: */
966: DprintQ((statp->options & RES_DEBUG) ||
967: (statp->pfcode & RES_PRF_REPLY),
968: (stdout, ";; old answer:\n"),
969: ans, (resplen > anssiz) ? anssiz : resplen);
970: goto wait;
971: }
972: if (!(statp->options & RES_INSECURE1) &&
1.2 christos 973: !res_ourserver_p(statp, (struct sockaddr *)(void *)&from)) {
1.1 christos 974: /*
975: * response from wrong server? ignore it.
976: * XXX - potential security hazard could
977: * be detected here.
978: */
979: DprintQ((statp->options & RES_DEBUG) ||
980: (statp->pfcode & RES_PRF_REPLY),
981: (stdout, ";; not our server:\n"),
982: ans, (resplen > anssiz) ? anssiz : resplen);
983: goto wait;
984: }
985: #ifdef RES_USE_EDNS0
986: if (anhp->rcode == FORMERR && (statp->options & RES_USE_EDNS0) != 0U) {
987: /*
988: * Do not retry if the server do not understand EDNS0.
989: * The case has to be captured here, as FORMERR packet do not
990: * carry query section, hence res_queriesmatch() returns 0.
991: */
992: DprintQ(statp->options & RES_DEBUG,
993: (stdout, "server rejected query with EDNS0:\n"),
994: ans, (resplen > anssiz) ? anssiz : resplen);
995: /* record the error */
996: statp->_flags |= RES_F_EDNS0ERR;
997: res_nclose(statp);
998: return (0);
999: }
1000: #endif
1001: if (!(statp->options & RES_INSECURE2) &&
1002: !res_queriesmatch(buf, buf + buflen,
1003: ans, ans + anssiz)) {
1004: /*
1005: * response contains wrong query? ignore it.
1006: * XXX - potential security hazard could
1007: * be detected here.
1008: */
1009: DprintQ((statp->options & RES_DEBUG) ||
1010: (statp->pfcode & RES_PRF_REPLY),
1011: (stdout, ";; wrong query name:\n"),
1012: ans, (resplen > anssiz) ? anssiz : resplen);
1013: goto wait;
1014: }
1015: if (anhp->rcode == SERVFAIL ||
1016: anhp->rcode == NOTIMP ||
1017: anhp->rcode == REFUSED) {
1018: DprintQ(statp->options & RES_DEBUG,
1019: (stdout, "server rejected query:\n"),
1020: ans, (resplen > anssiz) ? anssiz : resplen);
1021: res_nclose(statp);
1022: /* don't retry if called from dig */
1023: if (!statp->pfcode)
1024: return (0);
1025: }
1026: if (!(statp->options & RES_IGNTC) && anhp->tc) {
1027: /*
1028: * To get the rest of answer,
1029: * use TCP with same server.
1030: */
1031: Dprint(statp->options & RES_DEBUG,
1032: (stdout, ";; truncated answer\n"));
1033: *v_circuit = 1;
1034: res_nclose(statp);
1035: return (1);
1036: }
1037: /*
1038: * All is well, or the error is fatal. Signal that the
1039: * next nameserver ought not be tried.
1040: */
1041: return (resplen);
1042: }
1043:
1044: static void
1045: Aerror(const res_state statp, FILE *file, const char *string, int error,
1046: const struct sockaddr *address, int alen)
1047: {
1048: int save = errno;
1049: char hbuf[NI_MAXHOST];
1050: char sbuf[NI_MAXSERV];
1051:
1052: alen = alen;
1053:
1054: if ((statp->options & RES_DEBUG) != 0U) {
1.2 christos 1055: if (getnameinfo(address, (socklen_t)alen, hbuf, sizeof(hbuf),
1.1 christos 1056: sbuf, sizeof(sbuf), niflags)) {
1057: strncpy(hbuf, "?", sizeof(hbuf) - 1);
1058: hbuf[sizeof(hbuf) - 1] = '\0';
1059: strncpy(sbuf, "?", sizeof(sbuf) - 1);
1060: sbuf[sizeof(sbuf) - 1] = '\0';
1061: }
1062: fprintf(file, "res_send: %s ([%s].%s): %s\n",
1063: string, hbuf, sbuf, strerror(error));
1064: }
1065: errno = save;
1066: }
1067:
1068: static void
1069: Perror(const res_state statp, FILE *file, const char *string, int error) {
1070: int save = errno;
1071:
1072: if ((statp->options & RES_DEBUG) != 0U)
1073: fprintf(file, "res_send: %s: %s\n",
1074: string, strerror(error));
1075: errno = save;
1076: }
1077:
1078: static int
1079: sock_eq(struct sockaddr *a, struct sockaddr *b) {
1080: struct sockaddr_in *a4, *b4;
1081: struct sockaddr_in6 *a6, *b6;
1082:
1083: if (a->sa_family != b->sa_family)
1084: return 0;
1085: switch (a->sa_family) {
1086: case AF_INET:
1.2 christos 1087: a4 = (struct sockaddr_in *)(void *)a;
1088: b4 = (struct sockaddr_in *)(void *)b;
1.1 christos 1089: return a4->sin_port == b4->sin_port &&
1090: a4->sin_addr.s_addr == b4->sin_addr.s_addr;
1091: case AF_INET6:
1.2 christos 1092: a6 = (struct sockaddr_in6 *)(void *)a;
1093: b6 = (struct sockaddr_in6 *)(void *)b;
1.1 christos 1094: return a6->sin6_port == b6->sin6_port &&
1095: #ifdef HAVE_SIN6_SCOPE_ID
1096: a6->sin6_scope_id == b6->sin6_scope_id &&
1097: #endif
1098: IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr);
1099: default:
1100: return 0;
1101: }
1102: }
1103:
1.10 christos 1104: #if defined(NEED_PSELECT) && !defined(USE_POLL)
1.1 christos 1105: /* XXX needs to move to the porting library. */
1106: static int
1107: pselect(int nfds, void *rfds, void *wfds, void *efds,
1108: struct timespec *tsp, const sigset_t *sigmask)
1109: {
1110: struct timeval tv, *tvp;
1111: sigset_t sigs;
1112: int n;
1113:
1114: if (tsp) {
1115: tvp = &tv;
1116: tv = evTimeVal(*tsp);
1117: } else
1118: tvp = NULL;
1119: if (sigmask)
1120: sigprocmask(SIG_SETMASK, sigmask, &sigs);
1121: n = select(nfds, rfds, wfds, efds, tvp);
1122: if (sigmask)
1123: sigprocmask(SIG_SETMASK, &sigs, NULL);
1124: if (tsp)
1125: *tsp = evTimeSpec(tv);
1126: return (n);
1127: }
1128: #endif
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