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res_send.c @ b2b143f4

4.104.114.84.95

Last change on this file since b2b143f4 was b2b143f4, checked in by Joel Sherrill <joel.sherrill@…>, on 03/05/04 at 17:58:51

2004-03-05 Joel Sherrill <joel@…>

libblock/src/bdbuf.c, libblock/src/ramdisk.c, libcsupport/src/newlibc.c, libcsupport/src/sync.c, libmisc/cpuuse/cpuuse.c, libmisc/monitor/mon-symbols.c, libmisc/shell/cmds.c, libmisc/shell/shell.c, libnetworking/kern/kern_sysctl.c, libnetworking/lib/ftpfs.c, libnetworking/lib/tftpDriver.c, libnetworking/libc/gethostbydns.c, libnetworking/libc/gethostbyht.c, libnetworking/libc/gethostnamadr.c, libnetworking/libc/getnetbyht.c, libnetworking/libc/getnetnamadr.c, libnetworking/libc/inet_addr.c, libnetworking/libc/linkaddr.c, libnetworking/libc/map_v4v6.c, libnetworking/libc/ns_print.c, libnetworking/libc/ns_ttl.c, libnetworking/libc/nsap_addr.c, libnetworking/libc/rcmd.c, libnetworking/libc/res_debug.c, libnetworking/libc/res_mkupdate.c, libnetworking/libc/res_query.c, libnetworking/libc/res_send.c, libnetworking/libc/res_update.c, libnetworking/net/radix.c, libnetworking/rtems/mkrootfs.c, librpc/src/rpc/clnt_perror.c, librpc/src/rpc/rtems_rpc.c, librpc/src/rpc/svc.c, sapi/include/confdefs.h, score/macros/rtems/score/chain.inl, score/src/objectidtoname.c:

Property mode set to 100644

File size: 23.2 KB

Line
1	/*
2	* Copyright (c) 1985, 1989, 1993
3	* The Regents of the University of California. All rights reserved.
4	*
5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions
7	* are met:
8	* 1. Redistributions of source code must retain the above copyright
9	* notice, this list of conditions and the following disclaimer.
10	* 2. Redistributions in binary form must reproduce the above copyright
11	* notice, this list of conditions and the following disclaimer in the
12	* documentation and/or other materials provided with the distribution.
13	* 3. All advertising materials mentioning features or use of this software
14	* must display the following acknowledgement:
15	* This product includes software developed by the University of
16	* California, Berkeley and its contributors.
17	* 4. 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
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
54	/*
55	* Portions Copyright (c) 1996 by Internet Software Consortium.
56	*
57	* Permission to use, copy, modify, and distribute this software for any
58	* purpose with or without fee is hereby granted, provided that the above
59	* copyright notice and this permission notice appear in all copies.
60	*
61	* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
62	* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
63	* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
64	* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
65	* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
66	* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
67	* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
68	* SOFTWARE.
69	*/
70
71	#if defined(LIBC_SCCS) && !defined(lint)
72	static char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
73	static char orig_rcsid[] = "From: Id: res_send.c,v 8.20 1998/04/06 23:27:51 halley Exp $";
74	static char rcsid[] = "$Id$";
75	#endif /* LIBC_SCCS and not lint */
76
77	/*
78	* Send query to name server and wait for reply.
79	*/
80
81	/* Since we compile with strict ANSI we need to undef it to get
82	* prototypes for extensions
83	*/
84	#undef __STRICT_ANSI__
85
86	#include <sys/types.h>
87	#include <sys/param.h>
88	#include <sys/time.h>
89	#include <sys/socket.h>
90	#include <sys/uio.h>
91
92	#include <netinet/in.h>
93	#include <arpa/nameser.h>
94	#include <arpa/inet.h>
95
96	#include <errno.h>
97	#include <netdb.h>
98	#include <resolv.h>
99	#include <stdio.h>
100	#include <stdlib.h>
101	#include <string.h>
102	#include <unistd.h>
103	#if !defined(__rtems__)
104	#include <poll.h>
105	#endif
106
107	#include "res_config.h"
108
109	#if !defined(__rtems__)
110
111	#ifdef NOPOLL /* libc_r doesn't wrap poll yet() */
112	static int use_poll = 0;
113	#else
114	static int use_poll = 1; /* adapt to poll() syscall availability */
115	/* 0 = not present, 1 = try it, 2 = exists */
116	#endif
117	#endif
118
119	static int s = -1; /* socket used for communications */
120	static int connected = 0; /* is the socket connected */
121	static int vc = 0; /* is the socket a virtual circuit? */
122	static res_send_qhook Qhook = NULL;
123	static res_send_rhook Rhook = NULL;
124
125
126	#define CAN_RECONNECT 1
127
128	#ifndef DEBUG
129	# define Dprint(cond, args) /empty/
130	# define DprintQ(cond, args, query, size) /empty/
131	# define Aerror(file, string, error, address) /empty/
132	# define Perror(file, string, error) /empty/
133	#else
134	# define Dprint(cond, args) if (cond) {fprintf args;} else {}
135	# define DprintQ(cond, args, query, size) if (cond) {\
136	fprintf args;\
137	__fp_nquery(query, size, stdout);\
138	} else {}
139	static void
140	Aerror(file, string, error, address)
141	FILE *file;
142	char *string;
143	int error;
144	struct sockaddr_in address;
145	{
146	int save = errno;
147
148	if (_res.options & RES_DEBUG) {
149	fprintf(file, "res_send: %s ([%s].%u): %s\n",
150	string,
151	inet_ntoa(address.sin_addr),
152	ntohs(address.sin_port),
153	strerror(error));
154	}
155	errno = save;
156	}
157	static void
158	Perror(file, string, error)
159	FILE *file;
160	char *string;
161	int error;
162	{
163	int save = errno;
164
165	if (_res.options & RES_DEBUG) {
166	fprintf(file, "res_send: %s: %s\n",
167	string, strerror(error));
168	}
169	errno = save;
170	}
171	#endif
172
173	void
174	res_send_setqhook(hook)
175	res_send_qhook hook;
176	{
177
178	Qhook = hook;
179	}
180
181	void
182	res_send_setrhook(hook)
183	res_send_rhook hook;
184	{
185
186	Rhook = hook;
187	}
188
189	/* int
190	* res_isourserver(ina)
191	* looks up "ina" in _res.ns_addr_list[]
192	* returns:
193	* 0 : not found
194	* >0 : found
195	* author:
196	* paul vixie, 29may94
197	*/
198	int
199	res_isourserver(inp)
200	const struct sockaddr_in *inp;
201	{
202	struct sockaddr_in ina;
203	int ns, ret;
204
205	ina = *inp;
206	ret = 0;
207	for (ns = 0; ns < _res.nscount; ns++) {
208	const struct sockaddr_in *srv = &_res.nsaddr_list[ns];
209
210	if (srv->sin_family == ina.sin_family &&
211	srv->sin_port == ina.sin_port &&
212	(srv->sin_addr.s_addr == INADDR_ANY \|\|
213	srv->sin_addr.s_addr == ina.sin_addr.s_addr)) {
214	ret++;
215	break;
216	}
217	}
218	return (ret);
219	}
220
221	/* int
222	* res_nameinquery(name, type, class, buf, eom)
223	* look for (name,type,class) in the query section of packet (buf,eom)
224	* requires:
225	* buf + HFIXEDSZ <= eom
226	* returns:
227	* -1 : format error
228	* 0 : not found
229	* >0 : found
230	* author:
231	* paul vixie, 29may94
232	*/
233	int
234	res_nameinquery(name, type, class, buf, eom)
235	const char *name;
236	int type, class;
237	const u_char buf, eom;
238	{
239	const u_char *cp = buf + HFIXEDSZ;
240	int qdcount = ntohs(((HEADER*)buf)->qdcount);
241
242	while (qdcount-- > 0) {
243	char tname[MAXDNAME+1];
244	int n, ttype, tclass;
245
246	n = dn_expand(buf, eom, cp, tname, sizeof tname);
247	if (n < 0)
248	return (-1);
249	cp += n;
250	if (cp + 2 * INT16SZ > eom)
251	return (-1);
252	ttype = ns_get16(cp); cp += INT16SZ;
253	tclass = ns_get16(cp); cp += INT16SZ;
254	if (ttype == type &&
255	tclass == class &&
256	strcasecmp(tname, name) == 0)
257	return (1);
258	}
259	return (0);
260	}
261
262	/* int
263	* res_queriesmatch(buf1, eom1, buf2, eom2)
264	* is there a 1:1 mapping of (name,type,class)
265	* in (buf1,eom1) and (buf2,eom2)?
266	* returns:
267	* -1 : format error
268	* 0 : not a 1:1 mapping
269	* >0 : is a 1:1 mapping
270	* author:
271	* paul vixie, 29may94
272	*/
273	int
274	res_queriesmatch(buf1, eom1, buf2, eom2)
275	const u_char buf1, eom1;
276	const u_char buf2, eom2;
277	{
278	const u_char *cp = buf1 + HFIXEDSZ;
279	int qdcount = ntohs(((HEADER*)buf1)->qdcount);
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	*/
288	if ( (((HEADER *)buf1)->opcode == ns_o_update) &&
289	(((HEADER *)buf2)->opcode == ns_o_update) )
290	return (1);
291
292	if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
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_send(buf, buflen, ans, anssiz)
314	const u_char *buf;
315	int buflen;
316	u_char *ans;
317	int anssiz;
318	{
319	HEADER hp = (HEADER ) buf;
320	HEADER anhp = (HEADER ) ans;
321	int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns, n;
322	u_int badns; /* XXX NSMAX can't exceed #/bits in this variable */
323
324	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
325	/* errno should have been set by res_init() in this case. */
326	return (-1);
327	}
328	if (anssiz < HFIXEDSZ) {
329	errno = EINVAL;
330	return (-1);
331	}
332	DprintQ((_res.options & RES_DEBUG) \|\| (_res.pfcode & RES_PRF_QUERY),
333	(stdout, ";; res_send()\n"), buf, buflen);
334	v_circuit = (_res.options & RES_USEVC) \|\| buflen > PACKETSZ;
335	gotsomewhere = 0;
336	connreset = 0;
337	terrno = ETIMEDOUT;
338	badns = 0;
339
340	/*
341	* Send request, RETRY times, or until successful
342	*/
343	for (try = 0; try < _res.retry; try++) {
344	for (ns = 0; ns < _res.nscount; ns++) {
345	struct sockaddr_in *nsap = &_res.nsaddr_list[ns];
346	same_ns:
347	if (badns & (1 << ns)) {
348	res_close();
349	goto next_ns;
350	}
351
352	if (Qhook) {
353	int done = 0, loops = 0;
354
355	do {
356	res_sendhookact act;
357
358	act = (*Qhook)(&nsap, &buf, &buflen,
359	ans, anssiz, &resplen);
360	switch (act) {
361	case res_goahead:
362	done = 1;
363	break;
364	case res_nextns:
365	res_close();
366	goto next_ns;
367	case res_done:
368	return (resplen);
369	case res_modified:
370	/* give the hook another try */
371	if (++loops < 42) /doug adams/
372	break;
373	/FALLTHROUGH/
374	case res_error:
375	/FALLTHROUGH/
376	default:
377	return (-1);
378	}
379	} while (!done);
380	}
381
382	Dprint(_res.options & RES_DEBUG,
383	(stdout, ";; Querying server (# %d) address = %s\n",
384	ns + 1, inet_ntoa(nsap->sin_addr)));
385
386	if (v_circuit) {
387	int truncated;
388	#if !defined(__rtems__)
389	struct iovec iov[2];
390	#endif
391	u_short len;
392	u_char *cp;
393
394	/*
395	* Use virtual circuit;
396	* at most one attempt per server.
397	*/
398	try = _res.retry;
399	truncated = 0;
400	if (s < 0 \|\| !vc \|\| hp->opcode == ns_o_update) {
401	if (s >= 0)
402	res_close();
403
404	s = socket(PF_INET, SOCK_STREAM, 0);
405	if (s < 0) {
406	terrno = errno;
407	Perror(stderr, "socket(vc)", errno);
408	return (-1);
409	}
410	errno = 0;
411	if (connect(s, (struct sockaddr *)nsap,
412	sizeof *nsap) < 0) {
413	terrno = errno;
414	Aerror(stderr, "connect/vc",
415	errno, *nsap);
416	badns \|= (1 << ns);
417	res_close();
418	goto next_ns;
419	}
420	vc = 1;
421	}
422	/*
423	* Send length & message
424	*/
425	putshort((u_short)buflen, (u_char*)&len);
426	#if !defined(__rtems__)
427	iov[0].iov_base = (caddr_t)&len;
428	iov[0].iov_len = INT16SZ;
429	iov[1].iov_base = (caddr_t)buf;
430	iov[1].iov_len = buflen;
431	if (writev(s, iov, 2) != (INT16SZ + buflen)) {
432	#else
433	/*
434	* RTEMS doesn't have writev (yet)
435	*/
436	if ((write (s, &len, INT16SZ) != INT16SZ)
437	\|\| (write (s, buf, buflen) != buflen)) {
438	#endif
439	terrno = errno;
440	Perror(stderr, "write failed", errno);
441	badns \|= (1 << ns);
442	res_close();
443	goto next_ns;
444	}
445	/*
446	* Receive length & response
447	*/
448	read_len:
449	cp = ans;
450	len = INT16SZ;
451	while ((n = read(s, (char *)cp, (int)len)) > 0) {
452	cp += n;
453	if ((len -= n) <= 0)
454	break;
455	}
456	if (n <= 0) {
457	terrno = errno;
458	Perror(stderr, "read failed", errno);
459	res_close();
460	/*
461	* A long running process might get its TCP
462	* connection reset if the remote server was
463	* restarted. Requery the server instead of
464	* trying a new one. When there is only one
465	* server, this means that a query might work
466	* instead of failing. We only allow one reset
467	* per query to prevent looping.
468	*/
469	if (terrno == ECONNRESET && !connreset) {
470	connreset = 1;
471	res_close();
472	goto same_ns;
473	}
474	res_close();
475	goto next_ns;
476	}
477	resplen = ns_get16(ans);
478	if (resplen > anssiz) {
479	Dprint(_res.options & RES_DEBUG,
480	(stdout, ";; response truncated\n")
481	);
482	truncated = 1;
483	len = anssiz;
484	} else
485	len = resplen;
486	if (len < HFIXEDSZ) {
487	/*
488	* Undersized message.
489	*/
490	Dprint(_res.options & RES_DEBUG,
491	(stdout, ";; undersized: %d\n", len));
492	terrno = EMSGSIZE;
493	badns \|= (1 << ns);
494	res_close();
495	goto next_ns;
496	}
497	cp = ans;
498	while (len != 0 &&
499	(n = read(s, (char *)cp, (int)len)) > 0) {
500	cp += n;
501	len -= n;
502	}
503	if (n <= 0) {
504	terrno = errno;
505	Perror(stderr, "read(vc)", errno);
506	res_close();
507	goto next_ns;
508	}
509	if (truncated) {
510	/*
511	* Flush rest of answer
512	* so connection stays in synch.
513	*/
514	anhp->tc = 1;
515	len = resplen - anssiz;
516	while (len != 0) {
517	char junk[PACKETSZ];
518
519	n = (len > sizeof(junk)
520	? sizeof(junk)
521	: len);
522	if ((n = read(s, junk, n)) > 0)
523	len -= n;
524	else
525	break;
526	}
527	}
528	/*
529	* The calling applicating has bailed out of
530	* a previous call and failed to arrange to have
531	* the circuit closed or the server has got
532	* itself confused. Anyway drop the packet and
533	* wait for the correct one.
534	*/
535	if (hp->id != anhp->id) {
536	DprintQ((_res.options & RES_DEBUG) \|\|
537	(_res.pfcode & RES_PRF_REPLY),
538	(stdout, ";; old answer (unexpected):\n"),
539	ans, (resplen>anssiz)?anssiz:resplen);
540	goto read_len;
541	}
542	} else {
543	/*
544	* Use datagrams.
545	*/
546	#ifndef NOPOLL
547	struct pollfd pfd;
548	int msec;
549	#endif
550	struct timeval timeout;
551	#ifndef NOSELECT
552	fd_set dsmask, *dsmaskp;
553	int dsmasklen;
554	#endif
555	struct sockaddr_in from;
556	int fromlen;
557
558	if ((s < 0) \|\| vc) {
559	if (vc)
560	res_close();
561	s = socket(PF_INET, SOCK_DGRAM, 0);
562	if (s < 0) {
563	#ifndef CAN_RECONNECT
564	bad_dg_sock:
565	#endif
566	terrno = errno;
567	Perror(stderr, "socket(dg)", errno);
568	return (-1);
569	}
570	connected = 0;
571	}
572	#ifndef CANNOT_CONNECT_DGRAM
573	/*
574	* On a 4.3BSD+ machine (client and server,
575	* actually), sending to a nameserver datagram
576	* port with no nameserver will cause an
577	* ICMP port unreachable message to be returned.
578	* If our datagram socket is "connected" to the
579	* server, we get an ECONNREFUSED error on the next
580	* socket operation, and select returns if the
581	* error message is received. We can thus detect
582	* the absence of a nameserver without timing out.
583	* If we have sent queries to at least two servers,
584	* however, we don't want to remain connected,
585	* as we wish to receive answers from the first
586	* server to respond.
587	*/
588	if (_res.nscount == 1 \|\| (try == 0 && ns == 0)) {
589	/*
590	* Connect only if we are sure we won't
591	* receive a response from another server.
592	*/
593	if (!connected) {
594	if (connect(s, (struct sockaddr *)nsap,
595	sizeof *nsap
596	) < 0) {
597	Aerror(stderr,
598	"connect(dg)",
599	errno, *nsap);
600	badns \|= (1 << ns);
601	res_close();
602	goto next_ns;
603	}
604	connected = 1;
605	}
606	if (send(s, (char*)buf, buflen, 0) != buflen) {
607	Perror(stderr, "send", errno);
608	badns \|= (1 << ns);
609	res_close();
610	goto next_ns;
611	}
612	} else {
613	/*
614	* Disconnect if we want to listen
615	* for responses from more than one server.
616	*/
617	if (connected) {
618	#ifdef CAN_RECONNECT
619	struct sockaddr_in no_addr;
620
621	no_addr.sin_family = AF_INET;
622	no_addr.sin_addr.s_addr = INADDR_ANY;
623	no_addr.sin_port = 0;
624	(void) connect(s,
625	(struct sockaddr *)
626	&no_addr,
627	sizeof no_addr);
628	#else
629	int s1 = socket(PF_INET, SOCK_DGRAM,0);
630	if (s1 < 0)
631	goto bad_dg_sock;
632	(void) dup2(s1, s);
633	(void) close(s1);
634	Dprint(_res.options & RES_DEBUG,
635	(stdout, ";; new DG socket\n"))
636	#endif /* CAN_RECONNECT */
637	connected = 0;
638	errno = 0;
639	}
640	#endif /* !CANNOT_CONNECT_DGRAM */
641	if (sendto(s, (char*)buf, buflen, 0,
642	(struct sockaddr *)nsap,
643	sizeof *nsap)
644	!= buflen) {
645	Aerror(stderr, "sendto", errno, *nsap);
646	badns \|= (1 << ns);
647	res_close();
648	goto next_ns;
649	}
650	#ifndef CANNOT_CONNECT_DGRAM
651	}
652	#endif /* !CANNOT_CONNECT_DGRAM */
653
654	/*
655	* Wait for reply
656	*/
657	#ifndef NOPOLL
658	othersyscall:
659	if (use_poll) {
660	msec = (_res.retrans << try) * 1000;
661	if (try > 0)
662	msec /= _res.nscount;
663	if (msec <= 0)
664	msec = 1000;
665	} else {
666	#endif
667	timeout.tv_sec = (_res.retrans << try);
668	if (try > 0)
669	timeout.tv_sec /= _res.nscount;
670	if ((long) timeout.tv_sec <= 0)
671	timeout.tv_sec = 1;
672	timeout.tv_usec = 0;
673	#ifndef NOPOLL
674	}
675	#endif
676	wait:
677	if (s < 0) {
678	Perror(stderr, "s out-of-bounds", EMFILE);
679	res_close();
680	goto next_ns;
681	}
682	#ifndef NOPOLL
683	if (use_poll) {
684	struct sigaction sa, osa;
685	int sigsys_installed = 0;
686
687	pfd.fd = s;
688	pfd.events = POLLIN;
689	if (use_poll == 1) {
690	bzero(&sa, sizeof(sa));
691	sa.sa_handler = SIG_IGN;
692	if (sigaction(SIGSYS, &sa, &osa) >= 0)
693	sigsys_installed = 1;
694	}
695	n = poll(&pfd, 1, msec);
696	if (sigsys_installed == 1) {
697	int oerrno = errno;
698	sigaction(SIGSYS, &osa, NULL);
699	errno = oerrno;
700	}
701	/* XXX why does nosys() return EINVAL? */
702	if (n < 0 && (errno == ENOSYS \|\|
703	errno == EINVAL)) {
704	use_poll = 0;
705	goto othersyscall;
706	} else if (use_poll == 1)
707	use_poll = 2;
708	if (n < 0) {
709	if (errno == EINTR)
710	goto wait;
711	Perror(stderr, "poll", errno);
712	res_close();
713	goto next_ns;
714	}
715	} else {
716	#endif
717	#ifndef NOSELECT
718	dsmasklen = howmany(s + 1, NFDBITS) *
719	sizeof(fd_mask);
720	if (dsmasklen > sizeof(fd_set)) {
721	dsmaskp = (fd_set *)malloc(dsmasklen);
722	if (dsmaskp == NULL) {
723	res_close();
724	goto next_ns;
725	}
726	} else
727	dsmaskp = &dsmask;
728	/* only zero what we need */
729	bzero((char *)dsmaskp, dsmasklen);
730	FD_SET(s, dsmaskp);
731	n = select(s + 1, dsmaskp, (fd_set *)NULL,
732	(fd_set *)NULL, &timeout);
733	if (dsmaskp != &dsmask)
734	free(dsmaskp);
735	if (n < 0) {
736	if (errno == EINTR)
737	goto wait;
738	Perror(stderr, "select", errno);
739	res_close();
740	goto next_ns;
741	}
742	#endif
743	#ifndef NOPOLL
744	}
745	#endif
746
747	#ifdef NOSELECT
748	setsockopt (s, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof timeout);
749	#else
750	if (n == 0) {
751	/*
752	* timeout
753	*/
754	Dprint(_res.options & RES_DEBUG,
755	(stdout, ";; timeout\n"));
756	gotsomewhere = 1;
757	res_close();
758	goto next_ns;
759	}
760	#endif
761	errno = 0;
762	fromlen = sizeof(struct sockaddr_in);
763	resplen = recvfrom(s, (char*)ans, anssiz, 0,
764	(struct sockaddr *)&from, &fromlen);
765	if (resplen <= 0) {
766	#ifdef NOSELECT
767	if (errno == ETIMEDOUT) {
768	Dprint(_res.options & RES_DEBUG,
769	(stdout, ";; timeout\n"));
770	gotsomewhere = 1;
771	res_close();
772	goto next_ns;
773	}
774	#endif
775	Perror(stderr, "recvfrom", errno);
776	res_close();
777	goto next_ns;
778	}
779	gotsomewhere = 1;
780	if (resplen < HFIXEDSZ) {
781	/*
782	* Undersized message.
783	*/
784	Dprint(_res.options & RES_DEBUG,
785	(stdout, ";; undersized: %d\n",
786	resplen));
787	terrno = EMSGSIZE;
788	badns \|= (1 << ns);
789	res_close();
790	goto next_ns;
791	}
792	if (hp->id != anhp->id) {
793	/*
794	* response from old query, ignore it.
795	* XXX - potential security hazard could
796	* be detected here.
797	*/
798	DprintQ((_res.options & RES_DEBUG) \|\|
799	(_res.pfcode & RES_PRF_REPLY),
800	(stdout, ";; old answer:\n"),
801	ans, (resplen>anssiz)?anssiz:resplen);
802	goto wait;
803	}
804	#ifdef CHECK_SRVR_ADDR
805	if (!(_res.options & RES_INSECURE1) &&
806	!res_isourserver(&from)) {
807	/*
808	* response from wrong server? ignore it.
809	* XXX - potential security hazard could
810	* be detected here.
811	*/
812	DprintQ((_res.options & RES_DEBUG) \|\|
813	(_res.pfcode & RES_PRF_REPLY),
814	(stdout, ";; not our server:\n"),
815	ans, (resplen>anssiz)?anssiz:resplen);
816	goto wait;
817	}
818	#endif
819	if (!(_res.options & RES_INSECURE2) &&
820	!res_queriesmatch(buf, buf + buflen,
821	ans, ans + anssiz)) {
822	/*
823	* response contains wrong query? ignore it.
824	* XXX - potential security hazard could
825	* be detected here.
826	*/
827	DprintQ((_res.options & RES_DEBUG) \|\|
828	(_res.pfcode & RES_PRF_REPLY),
829	(stdout, ";; wrong query name:\n"),
830	ans, (resplen>anssiz)?anssiz:resplen);
831	goto wait;
832	}
833	if (anhp->rcode == SERVFAIL \|\|
834	anhp->rcode == NOTIMP \|\|
835	anhp->rcode == REFUSED) {
836	DprintQ(_res.options & RES_DEBUG,
837	(stdout, "server rejected query:\n"),
838	ans, (resplen>anssiz)?anssiz:resplen);
839	badns \|= (1 << ns);
840	res_close();
841	/* don't retry if called from dig */
842	if (!_res.pfcode)
843	goto next_ns;
844	}
845	if (!(_res.options & RES_IGNTC) && anhp->tc) {
846	/*
847	* get rest of answer;
848	* use TCP with same server.
849	*/
850	Dprint(_res.options & RES_DEBUG,
851	(stdout, ";; truncated answer\n"));
852	v_circuit = 1;
853	res_close();
854	goto same_ns;
855	}
856	} /if vc/dg/
857	Dprint((_res.options & RES_DEBUG) \|\|
858	((_res.pfcode & RES_PRF_REPLY) &&
859	(_res.pfcode & RES_PRF_HEAD1)),
860	(stdout, ";; got answer:\n"));
861	DprintQ((_res.options & RES_DEBUG) \|\|
862	(_res.pfcode & RES_PRF_REPLY),
863	(stdout, "%s", ""),
864	ans, (resplen>anssiz)?anssiz:resplen);
865	/*
866	* If using virtual circuits, we assume that the first server
867	* is preferred over the rest (i.e. it is on the local
868	* machine) and only keep that one open.
869	* If we have temporarily opened a virtual circuit,
870	* or if we haven't been asked to keep a socket open,
871	* close the socket.
872	*/
873	if ((v_circuit && (!(_res.options & RES_USEVC) \|\| ns != 0)) \|\|
874	!(_res.options & RES_STAYOPEN)) {
875	res_close();
876	}
877	if (Rhook) {
878	int done = 0, loops = 0;
879
880	do {
881	res_sendhookact act;
882
883	act = (*Rhook)(nsap, buf, buflen,
884	ans, anssiz, &resplen);
885	switch (act) {
886	case res_goahead:
887	case res_done:
888	done = 1;
889	break;
890	case res_nextns:
891	res_close();
892	goto next_ns;
893	case res_modified:
894	/* give the hook another try */
895	if (++loops < 42) /doug adams/
896	break;
897	/FALLTHROUGH/
898	case res_error:
899	/FALLTHROUGH/
900	default:
901	return (-1);
902	}
903	} while (!done);
904
905	}
906	return (resplen);
907	next_ns: ;
908	} /foreach ns/
909	} /foreach retry/
910	res_close();
911	if (!v_circuit) {
912	if (!gotsomewhere)
913	errno = ECONNREFUSED; /* no nameservers found */
914	else
915	errno = ETIMEDOUT; /* no answer obtained */
916	} else
917	errno = terrno;
918	return (-1);
919	}
920
921	/*
922	* This routine is for closing the socket if a virtual circuit is used and
923	* the program wants to close it. This provides support for endhostent()
924	* which expects to close the socket.
925	*
926	* This routine is not expected to be user visible.
927	*/
928	void
929	res_close()
930	{
931	if (s >= 0) {
932	(void) close(s);
933	s = -1;
934	connected = 0;
935	vc = 0;
936	}
937	}

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source: rtems/cpukit/libnetworking/libc/res_send.c @ b2b143f4

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