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Commit | Line | Data |
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28f540f4 | 1 | /* |
28f540f4 RM |
2 | * Copyright (c) 1988, 1993 |
3 | * The Regents of the University of California. All rights reserved. | |
df21c858 | 4 | * |
28f540f4 RM |
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. | |
28f540f4 RM |
13 | * 4. Neither the name of the University nor the names of its contributors |
14 | * may be used to endorse or promote products derived from this software | |
15 | * without specific prior written permission. | |
df21c858 | 16 | * |
28f540f4 RM |
17 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
27 | * SUCH DAMAGE. | |
b43b13ac UD |
28 | */ |
29 | ||
30 | /* | |
28f540f4 | 31 | * Portions Copyright (c) 1993 by Digital Equipment Corporation. |
df21c858 | 32 | * |
28f540f4 RM |
33 | * Permission to use, copy, modify, and distribute this software for any |
34 | * purpose with or without fee is hereby granted, provided that the above | |
35 | * copyright notice and this permission notice appear in all copies, and that | |
36 | * the name of Digital Equipment Corporation not be used in advertising or | |
37 | * publicity pertaining to distribution of the document or software without | |
38 | * specific, written prior permission. | |
df21c858 | 39 | * |
28f540f4 RM |
40 | * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL |
41 | * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES | |
42 | * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT | |
43 | * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL | |
44 | * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR | |
45 | * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS | |
46 | * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS | |
47 | * SOFTWARE. | |
b43b13ac UD |
48 | */ |
49 | ||
50 | /* | |
51 | * Portions Copyright (c) 1996-1999 by Internet Software Consortium. | |
52 | * | |
53 | * Permission to use, copy, modify, and distribute this software for any | |
54 | * purpose with or without fee is hereby granted, provided that the above | |
55 | * copyright notice and this permission notice appear in all copies. | |
56 | * | |
57 | * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS | |
58 | * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES | |
59 | * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE | |
60 | * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL | |
61 | * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR | |
62 | * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS | |
63 | * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS | |
64 | * SOFTWARE. | |
28f540f4 RM |
65 | */ |
66 | ||
67 | #if defined(LIBC_SCCS) && !defined(lint) | |
b43b13ac UD |
68 | static const char sccsid[] = "@(#)res_query.c 8.1 (Berkeley) 6/4/93"; |
69 | static const char rcsid[] = "$Id$"; | |
28f540f4 RM |
70 | #endif /* LIBC_SCCS and not lint */ |
71 | ||
df21c858 | 72 | #include <sys/types.h> |
28f540f4 RM |
73 | #include <sys/param.h> |
74 | #include <netinet/in.h> | |
75 | #include <arpa/inet.h> | |
76 | #include <arpa/nameser.h> | |
28f540f4 RM |
77 | #include <ctype.h> |
78 | #include <errno.h> | |
b43b13ac UD |
79 | #include <netdb.h> |
80 | #include <resolv.h> | |
81 | #include <stdio.h> | |
82 | #include <stdlib.h> | |
83 | #include <string.h> | |
28f540f4 | 84 | |
b43b13ac UD |
85 | /* Options. Leave them on. */ |
86 | /* #undef DEBUG */ | |
28f540f4 RM |
87 | |
88 | #if PACKETSZ > 1024 | |
89 | #define MAXPACKET PACKETSZ | |
90 | #else | |
91 | #define MAXPACKET 1024 | |
92 | #endif | |
93 | ||
28f540f4 RM |
94 | /* |
95 | * Formulate a normal query, send, and await answer. | |
96 | * Returned answer is placed in supplied buffer "answer". | |
97 | * Perform preliminary check of answer, returning success only | |
98 | * if no error is indicated and the answer count is nonzero. | |
99 | * Return the size of the response on success, -1 on error. | |
b43b13ac | 100 | * Error number is left in H_ERRNO. |
28f540f4 RM |
101 | * |
102 | * Caller must parse answer and determine whether it answers the question. | |
103 | */ | |
104 | int | |
b43b13ac UD |
105 | res_nquery(res_state statp, |
106 | const char *name, /* domain name */ | |
107 | int class, int type, /* class and type of query */ | |
108 | u_char *answer, /* buffer to put answer */ | |
109 | int anslen) /* size of answer buffer */ | |
28f540f4 RM |
110 | { |
111 | u_char buf[MAXPACKET]; | |
b43b13ac | 112 | HEADER *hp = (HEADER *) answer; |
28f540f4 RM |
113 | int n; |
114 | ||
115 | hp->rcode = NOERROR; /* default */ | |
116 | ||
28f540f4 | 117 | #ifdef DEBUG |
b43b13ac | 118 | if (statp->options & RES_DEBUG) |
28f540f4 RM |
119 | printf(";; res_query(%s, %d, %d)\n", name, class, type); |
120 | #endif | |
121 | ||
b43b13ac UD |
122 | n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL, |
123 | buf, sizeof(buf)); | |
28f540f4 RM |
124 | if (n <= 0) { |
125 | #ifdef DEBUG | |
b43b13ac | 126 | if (statp->options & RES_DEBUG) |
28f540f4 RM |
127 | printf(";; res_query: mkquery failed\n"); |
128 | #endif | |
b43b13ac | 129 | RES_SET_H_ERRNO(statp, NO_RECOVERY); |
28f540f4 RM |
130 | return (n); |
131 | } | |
b43b13ac | 132 | n = res_nsend(statp, buf, n, answer, anslen); |
28f540f4 RM |
133 | if (n < 0) { |
134 | #ifdef DEBUG | |
b43b13ac | 135 | if (statp->options & RES_DEBUG) |
28f540f4 RM |
136 | printf(";; res_query: send error\n"); |
137 | #endif | |
b43b13ac | 138 | RES_SET_H_ERRNO(statp, TRY_AGAIN); |
28f540f4 RM |
139 | return (n); |
140 | } | |
141 | ||
142 | if (hp->rcode != NOERROR || ntohs(hp->ancount) == 0) { | |
143 | #ifdef DEBUG | |
b43b13ac | 144 | if (statp->options & RES_DEBUG) |
28f540f4 RM |
145 | printf(";; rcode = %d, ancount=%d\n", hp->rcode, |
146 | ntohs(hp->ancount)); | |
147 | #endif | |
148 | switch (hp->rcode) { | |
149 | case NXDOMAIN: | |
b43b13ac | 150 | RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); |
28f540f4 RM |
151 | break; |
152 | case SERVFAIL: | |
b43b13ac | 153 | RES_SET_H_ERRNO(statp, TRY_AGAIN); |
28f540f4 RM |
154 | break; |
155 | case NOERROR: | |
b43b13ac | 156 | RES_SET_H_ERRNO(statp, NO_DATA); |
28f540f4 RM |
157 | break; |
158 | case FORMERR: | |
159 | case NOTIMP: | |
160 | case REFUSED: | |
161 | default: | |
b43b13ac | 162 | RES_SET_H_ERRNO(statp, NO_RECOVERY); |
28f540f4 RM |
163 | break; |
164 | } | |
165 | return (-1); | |
166 | } | |
167 | return (n); | |
168 | } | |
169 | ||
170 | /* | |
171 | * Formulate a normal query, send, and retrieve answer in supplied buffer. | |
172 | * Return the size of the response on success, -1 on error. | |
173 | * If enabled, implement search rules until answer or unrecoverable failure | |
b43b13ac | 174 | * is detected. Error code, if any, is left in H_ERRNO. |
28f540f4 RM |
175 | */ |
176 | int | |
b43b13ac UD |
177 | res_nsearch(res_state statp, |
178 | const char *name, /* domain name */ | |
179 | int class, int type, /* class and type of query */ | |
180 | u_char *answer, /* buffer to put answer */ | |
181 | int anslen) /* size of answer */ | |
28f540f4 | 182 | { |
b43b13ac | 183 | const char *cp, * const *domain; |
28f540f4 | 184 | HEADER *hp = (HEADER *) answer; |
b43b13ac | 185 | char tmp[NS_MAXDNAME]; |
28f540f4 | 186 | u_int dots; |
b43b13ac UD |
187 | int trailing_dot, ret; |
188 | int got_nodata = 0, got_servfail = 0, root_on_list = 0; | |
28f540f4 | 189 | |
c4029823 | 190 | __set_errno (0); |
b43b13ac UD |
191 | RES_SET_H_ERRNO(statp, HOST_NOT_FOUND); /* True if we never query. */ |
192 | ||
28f540f4 | 193 | dots = 0; |
b43b13ac | 194 | for (cp = name; *cp != '\0'; cp++) |
28f540f4 RM |
195 | dots += (*cp == '.'); |
196 | trailing_dot = 0; | |
197 | if (cp > name && *--cp == '.') | |
198 | trailing_dot++; | |
199 | ||
b43b13ac UD |
200 | /* If there aren't any dots, it could be a user-level alias. */ |
201 | if (!dots && (cp = res_hostalias(statp, name, tmp, sizeof tmp))!= NULL) | |
202 | return (res_nquery(statp, cp, class, type, answer, anslen)); | |
28f540f4 RM |
203 | |
204 | /* | |
b43b13ac UD |
205 | * If there are enough dots in the name, do no searching. |
206 | * (The threshold can be set with the "ndots" option.) | |
28f540f4 | 207 | */ |
b43b13ac UD |
208 | if (dots >= statp->ndots || trailing_dot) |
209 | return (res_nquerydomain(statp, name, NULL, class, type, | |
210 | answer, anslen)); | |
28f540f4 RM |
211 | |
212 | /* | |
213 | * We do at least one level of search if | |
214 | * - there is no dot and RES_DEFNAME is set, or | |
215 | * - there is at least one dot, there is no trailing dot, | |
216 | * and RES_DNSRCH is set. | |
217 | */ | |
b43b13ac UD |
218 | if ((!dots && (statp->options & RES_DEFNAMES) != 0) || |
219 | (dots && !trailing_dot && (statp->options & RES_DNSRCH) != 0)) { | |
28f540f4 RM |
220 | int done = 0; |
221 | ||
b43b13ac | 222 | for (domain = (const char * const *)statp->dnsrch; |
28f540f4 RM |
223 | *domain && !done; |
224 | domain++) { | |
225 | ||
b43b13ac UD |
226 | if (domain[0][0] == '\0' || |
227 | (domain[0][0] == '.' && domain[0][1] == '\0')) | |
228 | root_on_list++; | |
229 | ||
230 | ret = res_nquerydomain(statp, name, *domain, | |
231 | class, type, | |
232 | answer, anslen); | |
28f540f4 RM |
233 | if (ret > 0) |
234 | return (ret); | |
235 | ||
236 | /* | |
237 | * If no server present, give up. | |
238 | * If name isn't found in this domain, | |
239 | * keep trying higher domains in the search list | |
240 | * (if that's enabled). | |
241 | * On a NO_DATA error, keep trying, otherwise | |
242 | * a wildcard entry of another type could keep us | |
243 | * from finding this entry higher in the domain. | |
244 | * If we get some other error (negative answer or | |
245 | * server failure), then stop searching up, | |
246 | * but try the input name below in case it's | |
247 | * fully-qualified. | |
248 | */ | |
249 | if (errno == ECONNREFUSED) { | |
b43b13ac | 250 | RES_SET_H_ERRNO(statp, TRY_AGAIN); |
28f540f4 RM |
251 | return (-1); |
252 | } | |
253 | ||
b43b13ac | 254 | switch (statp->res_h_errno) { |
28f540f4 RM |
255 | case NO_DATA: |
256 | got_nodata++; | |
257 | /* FALLTHROUGH */ | |
258 | case HOST_NOT_FOUND: | |
259 | /* keep trying */ | |
260 | break; | |
261 | case TRY_AGAIN: | |
262 | if (hp->rcode == SERVFAIL) { | |
263 | /* try next search element, if any */ | |
264 | got_servfail++; | |
265 | break; | |
266 | } | |
267 | /* FALLTHROUGH */ | |
268 | default: | |
269 | /* anything else implies that we're done */ | |
270 | done++; | |
271 | } | |
272 | ||
273 | /* if we got here for some reason other than DNSRCH, | |
274 | * we only wanted one iteration of the loop, so stop. | |
275 | */ | |
b43b13ac | 276 | if ((statp->options & RES_DNSRCH) == 0) |
28f540f4 RM |
277 | done++; |
278 | } | |
279 | } | |
280 | ||
b43b13ac UD |
281 | /* |
282 | * If the name has any dots at all, and "." is not on the search | |
283 | * list, then try an as-is query now. | |
28f540f4 | 284 | */ |
b43b13ac UD |
285 | if (statp->ndots) { |
286 | ret = res_nquerydomain(statp, name, NULL, class, type, | |
287 | answer, anslen); | |
28f540f4 RM |
288 | if (ret > 0) |
289 | return (ret); | |
290 | } | |
291 | ||
292 | /* if we got here, we didn't satisfy the search. | |
b43b13ac | 293 | * if we did an initial full query, return that query's H_ERRNO |
28f540f4 RM |
294 | * (note that we wouldn't be here if that query had succeeded). |
295 | * else if we ever got a nodata, send that back as the reason. | |
b43b13ac | 296 | * else send back meaningless H_ERRNO, that being the one from |
28f540f4 RM |
297 | * the last DNSRCH we did. |
298 | */ | |
b43b13ac UD |
299 | if (got_nodata) |
300 | RES_SET_H_ERRNO(statp, NO_DATA); | |
28f540f4 | 301 | else if (got_servfail) |
b43b13ac | 302 | RES_SET_H_ERRNO(statp, TRY_AGAIN); |
28f540f4 RM |
303 | return (-1); |
304 | } | |
305 | ||
306 | /* | |
307 | * Perform a call on res_query on the concatenation of name and domain, | |
308 | * removing a trailing dot from name if domain is NULL. | |
309 | */ | |
310 | int | |
b43b13ac UD |
311 | res_nquerydomain(res_state statp, |
312 | const char *name, | |
313 | const char *domain, | |
314 | int class, int type, /* class and type of query */ | |
315 | u_char *answer, /* buffer to put answer */ | |
316 | int anslen) /* size of answer */ | |
28f540f4 | 317 | { |
b43b13ac | 318 | char nbuf[MAXDNAME]; |
28f540f4 | 319 | const char *longname = nbuf; |
b43b13ac | 320 | int n, d; |
28f540f4 RM |
321 | |
322 | #ifdef DEBUG | |
b43b13ac UD |
323 | if (statp->options & RES_DEBUG) |
324 | printf(";; res_nquerydomain(%s, %s, %d, %d)\n", | |
28f540f4 RM |
325 | name, domain?domain:"<Nil>", class, type); |
326 | #endif | |
327 | if (domain == NULL) { | |
328 | /* | |
329 | * Check for trailing '.'; | |
330 | * copy without '.' if present. | |
331 | */ | |
b43b13ac UD |
332 | n = strlen(name); |
333 | if (n >= MAXDNAME) { | |
334 | RES_SET_H_ERRNO(statp, NO_RECOVERY); | |
335 | return (-1); | |
336 | } | |
337 | n--; | |
338 | if (n >= 0 && name[n] == '.') { | |
339 | strncpy(nbuf, name, n); | |
28f540f4 RM |
340 | nbuf[n] = '\0'; |
341 | } else | |
342 | longname = name; | |
b43b13ac UD |
343 | } else { |
344 | n = strlen(name); | |
345 | d = strlen(domain); | |
346 | if (n + d + 1 >= MAXDNAME) { | |
347 | RES_SET_H_ERRNO(statp, NO_RECOVERY); | |
348 | return (-1); | |
349 | } | |
350 | sprintf(nbuf, "%s.%s", name, domain); | |
351 | } | |
352 | return (res_nquery(statp, longname, class, type, answer, anslen)); | |
28f540f4 RM |
353 | } |
354 | ||
845dcb57 | 355 | const char * |
b43b13ac UD |
356 | res_hostalias(const res_state statp, const char *name, char *dst, size_t siz) { |
357 | char *file, *cp1, *cp2; | |
28f540f4 | 358 | char buf[BUFSIZ]; |
b43b13ac | 359 | FILE *fp; |
28f540f4 | 360 | |
b43b13ac | 361 | if (statp->options & RES_NOALIASES) |
3d61b63c | 362 | return (NULL); |
d68171ed | 363 | file = __secure_getenv("HOSTALIASES"); |
28f540f4 RM |
364 | if (file == NULL || (fp = fopen(file, "r")) == NULL) |
365 | return (NULL); | |
3d61b63c | 366 | setbuf(fp, NULL); |
28f540f4 RM |
367 | buf[sizeof(buf) - 1] = '\0'; |
368 | while (fgets(buf, sizeof(buf), fp)) { | |
369 | for (cp1 = buf; *cp1 && !isspace(*cp1); ++cp1) | |
370 | ; | |
371 | if (!*cp1) | |
372 | break; | |
373 | *cp1 = '\0'; | |
b43b13ac | 374 | if (ns_samename(buf, name) == 1) { |
28f540f4 RM |
375 | while (isspace(*++cp1)) |
376 | ; | |
377 | if (!*cp1) | |
378 | break; | |
379 | for (cp2 = cp1 + 1; *cp2 && !isspace(*cp2); ++cp2) | |
380 | ; | |
b43b13ac UD |
381 | *cp2 = '\0'; |
382 | strncpy(dst, cp1, siz - 1); | |
383 | dst[siz - 1] = '\0'; | |
28f540f4 | 384 | fclose(fp); |
b43b13ac | 385 | return (dst); |
28f540f4 RM |
386 | } |
387 | } | |
388 | fclose(fp); | |
389 | return (NULL); | |
390 | } |