2 * ++Copyright++ 1985, 1989, 1993
4 * Copyright (c) 1985, 1989, 1993
5 * The Regents of the University of California. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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11 * notice, this list of conditions and the following disclaimer.
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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
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20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
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35 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
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
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40 * the name of Digital Equipment Corporation not be used in advertising or
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45 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
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56 #if defined(LIBC_SCCS) && !defined(lint)
57 static char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
58 static char rcsid[] = "$Id$";
59 #endif /* LIBC_SCCS and not lint */
62 * if you talk to a lot
63 * of multi-homed SunOS
64 * ("broken") name servers.
66 #define CHECK_SRVR_ADDR 1 /* XXX - should be in options.h */
69 * Send query to name server and wait for reply.
72 #include <sys/types.h>
73 #include <sys/param.h>
75 #include <sys/socket.h>
77 #include <netinet/in.h>
78 #include <arpa/nameser.h>
79 #include <arpa/inet.h>
85 #if defined(BSD) && (BSD >= 199306)
90 # include "../conf/portability.h"
93 #if defined(USE_OPTIONS_H)
94 # include <../conf/options.h>
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 circuit? */
102 /* XXX - should be in portability.h */
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)))
111 /* XXX - this should be done in portability.h */
112 #if (defined(BSD) && (BSD >= 199103)) || defined(linux)
113 # define CAN_RECONNECT 1
115 # define CAN_RECONNECT 0
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*/
124 # define Dprint(cond, args) if (cond) {fprintf args;} else {}
125 # define DprintQ(cond, args, query, size) if (cond) {\
127 __fp_nquery(query, size, stdout);\
130 Aerror(file, string, error, address)
134 struct sockaddr_in address;
138 if (_res.options & RES_DEBUG) {
139 fprintf(file, "res_send: %s ([%s].%u): %s\n",
141 inet_ntoa(address.sin_addr),
142 ntohs(address.sin_port),
148 Perror(file, string, error)
155 if (_res.options & RES_DEBUG) {
156 fprintf(file, "res_send: %s: %s\n",
157 string, strerror(error));
163 static res_send_qhook Qhook = NULL;
164 static res_send_rhook Rhook = NULL;
167 res_send_setqhook(hook)
175 res_send_setrhook(hook)
183 * res_isourserver(ina)
184 * looks up "ina" in _res.ns_addr_list[]
189 * paul vixie, 29may94
193 const struct sockaddr_in *inp;
195 struct sockaddr_in ina;
196 register int ns, ret;
200 for (ns = 0; ns < _res.nscount; ns++) {
201 register const struct sockaddr_in *srv = &_res.nsaddr_list[ns];
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)) {
215 * res_nameinquery(name, type, class, buf, eom)
216 * look for (name,type,class) in the query section of packet (buf,eom)
222 * paul vixie, 29may94
225 res_nameinquery(name, type, class, buf, eom)
227 register int type, class;
228 const u_char *buf, *eom;
230 register const u_char *cp = buf + HFIXEDSZ;
231 int qdcount = ntohs(((HEADER*)buf)->qdcount);
233 while (qdcount-- > 0) {
234 char tname[MAXDNAME+1];
235 register int n, ttype, tclass;
237 n = dn_expand(buf, eom, cp, tname, sizeof tname);
241 ttype = _getshort(cp); cp += INT16SZ;
242 tclass = _getshort(cp); cp += INT16SZ;
245 strcasecmp(tname, name) == 0)
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)?
257 * 0 : not a 1:1 mapping
258 * >0 : is a 1:1 mapping
260 * paul vixie, 29may94
263 res_queriesmatch(buf1, eom1, buf2, eom2)
264 const u_char *buf1, *eom1;
265 const u_char *buf2, *eom2;
267 register const u_char *cp = buf1 + HFIXEDSZ;
268 int qdcount = ntohs(((HEADER*)buf1)->qdcount);
270 if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
272 while (qdcount-- > 0) {
273 char tname[MAXDNAME+1];
274 register int n, ttype, tclass;
276 n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
280 ttype = _getshort(cp); cp += INT16SZ;
281 tclass = _getshort(cp); cp += INT16SZ;
282 if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
289 res_send(buf, buflen, ans, anssiz)
295 HEADER *hp = (HEADER *) buf;
296 HEADER *anhp = (HEADER *) ans;
297 int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns;
299 u_int badns; /* XXX NSMAX can't exceed #/bits in this var */
301 if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
302 /* errno should have been set by res_init() in this case. */
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;
314 * Send request, RETRY times, or until successful
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];
320 if (badns & (1 << ns)) {
326 int done = 0, loops = 0;
331 act = (*Qhook)(&nsap, &buf, &buflen,
332 ans, anssiz, &resplen);
343 /* give the hook another try */
344 if (++loops < 42) /*doug adams*/
355 Dprint(_res.options & RES_DEBUG,
356 (stdout, ";; Querying server (# %d) address = %s\n",
357 ns + 1, inet_ntoa(nsap->sin_addr)));
366 * Use virtual circuit;
367 * at most one attempt per server.
371 if ((s < 0) || (!vc)) {
375 s = socket(PF_INET, SOCK_STREAM, 0);
378 Perror(stderr, "socket(vc)", errno);
382 if (connect(s, (struct sockaddr *)nsap,
383 sizeof(struct sockaddr)) < 0) {
385 Aerror(stderr, "connect/vc",
394 * Send length & message
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)) {
403 Perror(stderr, "write failed", errno);
409 * Receive length & response
414 while ((n = read(s, (char *)cp, (int)len)) > 0) {
421 Perror(stderr, "read failed", errno);
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.
432 if (terrno == ECONNRESET && !connreset) {
440 resplen = _getshort(ans);
441 if (resplen > anssiz) {
442 Dprint(_res.options & RES_DEBUG,
443 (stdout, ";; response truncated\n")
451 (n = read(s, (char *)cp, (int)len)) > 0) {
457 Perror(stderr, "read(vc)", errno);
463 * Flush rest of answer
464 * so connection stays in synch.
467 len = resplen - anssiz;
471 n = (len > sizeof(junk)
474 if ((n = read(s, junk, n)) > 0)
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.
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);
498 struct timeval timeout;
500 struct sockaddr_in from;
506 s = socket(PF_INET, SOCK_DGRAM, 0);
512 Perror(stderr, "socket(dg)", errno);
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
532 if (_res.nscount == 1 || (try == 0 && ns == 0)) {
534 * Connect only if we are sure we won't
535 * receive a response from another server.
538 if (connect(s, (struct sockaddr *)nsap,
539 sizeof(struct sockaddr)
550 if (send(s, (char*)buf, buflen, 0) != buflen) {
551 Perror(stderr, "send", errno);
558 * Disconnect if we want to listen
559 * for responses from more than one server.
563 struct sockaddr_in no_addr;
565 no_addr.sin_family = AF_INET;
566 no_addr.sin_addr.s_addr = INADDR_ANY;
567 no_addr.sin_port = 0;
573 int s1 = socket(PF_INET, SOCK_DGRAM,0);
578 Dprint(_res.options & RES_DEBUG,
579 (stdout, ";; new DG socket\n"))
584 if (sendto(s, (char*)buf, buflen, 0,
585 (struct sockaddr *)nsap,
586 sizeof(struct sockaddr))
588 Aerror(stderr, "sendto", errno, *nsap);
598 timeout.tv_sec = (_res.retrans << try);
600 timeout.tv_sec /= _res.nscount;
601 if ((long) timeout.tv_sec <= 0)
604 if (s+1 > FD_SETSIZE) {
605 Perror(stderr, "s+1 > FD_SETSIZE", EMFILE);
612 n = select(s+1, &dsmask, (fd_set *)NULL,
613 (fd_set *)NULL, &timeout);
617 Perror(stderr, "select", errno);
625 Dprint(_res.options & RES_DEBUG,
626 (stdout, ";; timeout\n"));
632 fromlen = sizeof(struct sockaddr_in);
633 resplen = recvfrom(s, (char*)ans, anssiz, 0,
634 (struct sockaddr *)&from, &fromlen);
636 Perror(stderr, "recvfrom", errno);
641 if (hp->id != anhp->id) {
643 * response from old query, ignore it.
644 * XXX - potential security hazard could
647 DprintQ((_res.options & RES_DEBUG) ||
648 (_res.pfcode & RES_PRF_REPLY),
649 (stdout, ";; old answer:\n"),
650 ans, (resplen>anssiz)?anssiz:resplen);
654 if (!(_res.options & RES_INSECURE1) &&
655 !res_isourserver(&from)) {
657 * response from wrong server? ignore it.
658 * XXX - potential security hazard could
661 DprintQ((_res.options & RES_DEBUG) ||
662 (_res.pfcode & RES_PRF_REPLY),
663 (stdout, ";; not our server:\n"),
664 ans, (resplen>anssiz)?anssiz:resplen);
668 if (!(_res.options & RES_INSECURE2) &&
669 !res_queriesmatch(buf, buf + buflen,
670 ans, ans + anssiz)) {
672 * response contains wrong query? ignore it.
673 * XXX - potential security hazard could
676 DprintQ((_res.options & RES_DEBUG) ||
677 (_res.pfcode & RES_PRF_REPLY),
678 (stdout, ";; wrong query name:\n"),
679 ans, (resplen>anssiz)?anssiz:resplen);
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);
690 /* don't retry if called from dig */
694 if (!(_res.options & RES_IGNTC) && anhp->tc) {
696 * get rest of answer;
697 * use TCP with same server.
699 Dprint(_res.options & RES_DEBUG,
700 (stdout, ";; truncated answer\n"));
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),
713 ans, (resplen>anssiz)?anssiz:resplen);
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,
722 if ((v_circuit && (!(_res.options & RES_USEVC) || ns != 0)) ||
723 !(_res.options & RES_STAYOPEN)) {
727 int done = 0, loops = 0;
732 act = (*Rhook)(nsap, buf, buflen,
733 ans, anssiz, &resplen);
743 /* give the hook another try */
744 if (++loops < 42) /*doug adams*/
762 __set_errno (ECONNREFUSED); /* no nameservers found */
764 __set_errno (ETIMEDOUT); /* no answer obtained */
766 __set_errno (terrno);
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.
775 * This routine is not expected to be user visible.
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.
801 res_send(buf, buflen, ans, anssiz)
807 return (__res_send(buf, buflen, ans, anssiz));
809 #endif /* Ultrix 4.0 hackery */