2 * Copyright (c) 1988, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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
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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.
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
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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
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
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.
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
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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
55 * Portions Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
56 * Portions Copyright (c) 1996-2003 by Internet Software Consortium
58 * Permission to use, copy, modify, and distribute this software for any
59 * purpose with or without fee is hereby granted, provided that the above
60 * copyright notice and this permission notice appear in all copies.
62 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
63 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
64 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
65 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
66 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
67 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
68 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
70 * Internet Systems Consortium, Inc.
72 * Redwood City, CA 94063
77 #if defined(LIBC_SCCS) && !defined(lint)
78 static const char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93";
79 static const char rcsid[] = "$Id: res_query.c,v 1.4.2.1 2004/06/10 17:59:44 dhankins Exp $";
80 #endif /* LIBC_SCCS and not lint */
82 #include <sys/types.h>
83 #include <sys/param.h>
84 #include <netinet/in.h>
85 #include <arpa/inet.h>
92 #include <sys/socket.h>
94 #include "minires/minires.h"
95 #include "arpa/nameser.h"
97 /* Options. Leave them on. */
101 #define MAXPACKET PACKETSZ
103 #define MAXPACKET 1024
107 * Formulate a normal query, send, and await answer.
108 * Returned answer is placed in supplied buffer "answer".
109 * Perform preliminary check of answer, returning success only
110 * if no error is indicated and the answer count is nonzero.
111 * Return the size of the response on success, -1 on error.
112 * Error number is left in H_ERRNO.
114 * Caller must parse answer and determine whether it answers the question.
117 res_nquery(res_state statp,
118 const char *name, /* domain name */
119 ns_class class, ns_type type, /* class and type of query */
120 double *answer, /* buffer to put answer */
122 unsigned *ansret) /* size of answer buffer */
124 double buf[MAXPACKET / sizeof (double)];
125 HEADER *hp = (HEADER *) answer;
129 hp->rcode = NOERROR; /* default */
132 if (statp->options & RES_DEBUG)
133 printf(";; res_query(%s, %d, %d)\n", name, class, type);
136 rcode = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL,
137 buf, sizeof(buf), &n);
138 if (rcode != ISC_R_SUCCESS) {
140 if (statp->options & RES_DEBUG)
141 printf(";; res_query: mkquery failed\n");
143 RES_SET_H_ERRNO(statp, NO_RECOVERY);
146 rcode = res_nsend(statp, buf, n, answer, anslen, &n);
147 if (rcode != ISC_R_SUCCESS) {
149 if (statp->options & RES_DEBUG)
150 printf(";; res_query: send error\n");
152 RES_SET_H_ERRNO(statp, TRY_AGAIN);
156 if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
158 if (statp->options & RES_DEBUG)
159 printf(";; rcode = %d, ancount=%d\n", hp->rcode,
164 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
167 RES_SET_H_ERRNO(statp, TRY_AGAIN);
170 RES_SET_H_ERRNO(statp, NO_DATA);
176 RES_SET_H_ERRNO(statp, NO_RECOVERY);
179 return ns_rcode_to_isc (hp -> rcode);
182 return ISC_R_SUCCESS;
187 * Formulate a normal query, send, and retrieve answer in supplied buffer.
188 * Return the size of the response on success, -1 on error.
189 * If enabled, implement search rules until answer or unrecoverable failure
190 * is detected. Error code, if any, is left in H_ERRNO.
193 res_nsearch(res_state statp,
194 const char *name, /* domain name */
195 ns_class class, ns_type type, /* class and type of query */
196 double *answer, /* buffer to put answer */
198 unsigned *ansret) /* size of answer */
200 const char *cp, * const *domain;
201 HEADER *hp = (HEADER *) answer;
202 char tmp[NS_MAXDNAME];
204 int trailing_dot, ret;
205 int got_nodata = 0, got_servfail = 0, root_on_list = 0;
209 RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /* True if we never query. */
212 for (cp = name; *cp != '\0'; cp++)
213 dots += (*cp == '.');
215 if (cp > name && *--cp == '.')
218 /* If there aren't any dots, it could be a user-level alias. */
219 if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL)
220 return res_nquery(statp, cp, class, type,
221 answer, anslen, ansret);
224 * If there are enough dots in the name, do no searching.
225 * (The threshold can be set with the "ndots" option.)
227 if (dots >= statp->ndots || trailing_dot)
228 return res_nquerydomain(statp, name, NULL, class, type,
229 answer, anslen, ansret);
232 * We do at least one level of search if
233 * - there is no dot and RES_DEFNAME is set, or
234 * - there is at least one dot, there is no trailing dot,
235 * and RES_DNSRCH is set.
237 if ((!dots && (statp->options & RES_DEFNAMES) != 0) ||
238 (dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) {
241 for (domain = (const char * const *)statp->dnsrch;
245 if (domain[0][0] == '\0' ||
246 (domain[0][0] == '.' && domain[0][1] == '\0'))
249 rcode = res_nquerydomain(statp, name, *domain,
251 answer, anslen, &ret);
252 if (rcode == ISC_R_SUCCESS && ret > 0) {
258 * If no server present, give up.
259 * If name isn't found in this domain,
260 * keep trying higher domains in the search list
261 * (if that's enabled).
262 * On a NO_DATA error, keep trying, otherwise
263 * a wildcard entry of another type could keep us
264 * from finding this entry higher in the domain.
265 * If we get some other error (negative answer or
266 * server failure), then stop searching up,
267 * but try the input name below in case it's
270 if (errno == ECONNREFUSED) {
271 RES_SET_H_ERRNO(statp, TRY_AGAIN);
272 return ISC_R_CONNREFUSED;
275 switch (statp->res_h_errno) {
283 if (hp->rcode == SERVFAIL) {
284 /* try next search element, if any */
290 /* anything else implies that we're done */
294 /* if we got here for some reason other than DNSRCH,
295 * we only wanted one iteration of the loop, so stop.
297 if ((statp->options & RES_DNSRCH) == 0)
303 * If the name has any dots at all, and "." is not on the search
304 * list, then try an as-is query now.
307 rcode = res_nquerydomain(statp, name, NULL, class, type,
308 answer, anslen, &ret);
309 if (rcode == ISC_R_SUCCESS && ret > 0) {
315 /* if we got here, we didn't satisfy the search.
316 * if we did an initial full query, return that query's H_ERRNO
317 * (note that we wouldn't be here if that query had succeeded).
318 * else if we ever got a nodata, send that back as the reason.
319 * else send back meaningless H_ERRNO, that being the one from
320 * the last DNSRCH we did.
323 RES_SET_H_ERRNO(statp, NO_DATA);
324 return ISC_R_NOTFOUND;
325 } else if (got_servfail) {
326 RES_SET_H_ERRNO(statp, TRY_AGAIN);
327 return ISC_R_TIMEDOUT;
329 return ISC_R_UNEXPECTED;
334 * Perform a call on res_query on the concatenation of name and domain,
335 * removing a trailing dot from name if domain is NULL.
338 res_nquerydomain(res_state statp,
341 ns_class class, ns_type type,
347 const char *longname = nbuf;
351 if (statp->options & RES_DEBUG)
352 printf(";; res_nquerydomain(%s, %s, %d, %d)\n",
353 name, domain?domain:"<Nil>", class, type);
355 if (domain == NULL) {
357 * Check for trailing '.';
358 * copy without '.' if present.
362 RES_SET_H_ERRNO(statp, NO_RECOVERY);
363 return ISC_R_NOSPACE;
366 if (n >= 0 && name[n] == '.') {
367 strncpy(nbuf, name, (unsigned)n);
374 if (n + d + 1 >= MAXDNAME) {
375 RES_SET_H_ERRNO(statp, NO_RECOVERY);
376 return ISC_R_NOSPACE;
378 sprintf(nbuf, "%s.%s", name, domain);
380 return res_nquery(statp,
381 longname, class, type, answer, anslen, ansret);
385 res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) {
386 char *file, *cp1, *cp2;
390 if (statp->options & RES_NOALIASES)
392 file = getenv("HOSTALIASES");
393 if (file == NULL || (fp = fopen(file, "r")) == NULL)
396 buf[sizeof(buf) - 1] = '\0';
397 while (fgets(buf, sizeof(buf), fp)) {
398 for (cp1 = buf; *cp1 && !isspace(*cp1); ++cp1)
403 if (ns_samename(buf, name) == 1) {
404 while (isspace(*++cp1))
408 for (cp2 = cp1 + 1; *cp2 && !isspace(*cp2); ++cp2)
411 strncpy(dst, cp1, siz - 1);