1 /*
2 * Copyright (c) 1985, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Portions copyright (c) 1999, 2000
6 * Intel Corporation.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 *
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 *
23 * This product includes software developed by the University of
24 * California, Berkeley, Intel Corporation, and its contributors.
25 *
26 * 4. Neither the name of University, Intel Corporation, or their respective
27 * contributors may be used to endorse or promote products derived from
28 * this software without specific prior written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS, INTEL CORPORATION AND
31 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
32 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
33 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS,
34 * INTEL CORPORATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
35 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
40 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
41 *
42 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
43 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
44 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
45 * SUCH DAMAGE.
46 */
47
48 /*
49 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
50 *
51 * Permission to use, copy, modify, and distribute this software for any
52 * purpose with or without fee is hereby granted, provided that the above
53 * copyright notice and this permission notice appear in all copies, and that
54 * the name of Digital Equipment Corporation not be used in advertising or
55 * publicity pertaining to distribution of the document or software without
56 * specific, written prior permission.
57 *
58 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
59 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
60 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
61 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
62 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
63 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
64 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
65 * SOFTWARE.
66 */
67
68 /*
69 * Portions Copyright (c) 1996 by Internet Software Consortium.
70 *
71 * Permission to use, copy, modify, and distribute this software for any
72 * purpose with or without fee is hereby granted, provided that the above
73 * copyright notice and this permission notice appear in all copies.
74 *
75 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
76 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
77 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
78 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
79 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
80 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
81 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
82 * SOFTWARE.
83 */
84
85 #if defined(LIBC_SCCS) && !defined(lint)
86 static char sccsid[] = "@(#)res_init.c 8.1 (Berkeley) 6/7/93";
87 static char orig_rcsid[] = "From: Id: res_init.c,v 8.7 1996/11/18 09:10:04 vixie Exp $";
88 static char rcsid[] = "$Id: res_init.c,v 1.1.1.1 2003/11/19 01:51:37 kyu3 Exp $";
89 #endif /* LIBC_SCCS and not lint */
90
91 #include <sys/types.h>
92 #include <sys/param.h>
93 #include <sys/socket.h>
94 #include <sys/time.h>
95 #include <netinet/in.h>
96 #include <arpa/inet.h>
97 #include <arpa/nameser.h>
98 #include <ctype.h>
99 #include <resolv.h>
100 #include <stdio.h>
101 #include <stdlib.h>
102 #include <string.h>
103 #include <unistd.h>
104
105 #include "res_config.h"
106
107 static void res_setoptions __P((char *, char *));
108
109 #ifdef RESOLVSORT
110 static const char sort_mask[] = "/&";
111 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
112 static u_int32_t net_mask __P((struct in_addr));
113 #endif
114
115 #if !defined(isascii) /* XXX - could be a function */
116 # define isascii(c) (!(c & 0200))
117 #endif
118
119 /*
120 * Resolver state default settings.
121 */
122
123 struct __res_state _res
124 # if defined(__BIND_RES_TEXT)
125 = { RES_TIMEOUT, } /* Motorola, et al. */
126 # endif
127 ;
128
129
130 /*
131 * Set up default settings. If the configuration file exist, the values
132 * there will have precedence. Otherwise, the server address is set to
133 * INADDR_ANY and the default domain name comes from the gethostname().
134 *
135 * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
136 * rather than INADDR_ANY ("0.0.0.0") as the default name server address
137 * since it was noted that INADDR_ANY actually meant ``the first interface
138 * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
139 * it had to be "up" in order for you to reach your own name server. It
140 * was later decided that since the recommended practice is to always
141 * install local static routes through 127.0.0.1 for all your network
142 * interfaces, that we could solve this problem without a code change.
143 *
144 * The configuration file should always be used, since it is the only way
145 * to specify a default domain. If you are running a server on your local
146 * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
147 * in the configuration file.
148 *
149 * Return 0 if completes successfully, -1 on error
150 */
151 int
res_init()152 res_init()
153 {
154 register FILE *fp;
155 register char *cp, **pp;
156 register int n;
157 char buf[MAXDNAME];
158 int nserv = 0; /* number of nameserver records read from file */
159 int haveenv = 0;
160 int havesearch = 0;
161 #ifdef RESOLVSORT
162 int nsort = 0;
163 char *net;
164 #endif
165 #ifndef RFC1535
166 int dots;
167 #endif
168
169 /*
170 * These three fields used to be statically initialized. This made
171 * it hard to use this code in a shared library. It is necessary,
172 * now that we're doing dynamic initialization here, that we preserve
173 * the old semantics: if an application modifies one of these three
174 * fields of _res before res_init() is called, res_init() will not
175 * alter them. Of course, if an application is setting them to
176 * _zero_ before calling res_init(), hoping to override what used
177 * to be the static default, we can't detect it and unexpected results
178 * will follow. Zero for any of these fields would make no sense,
179 * so one can safely assume that the applications were already getting
180 * unexpected results.
181 *
182 * _res.options is tricky since some apps were known to diddle the bits
183 * before res_init() was first called. We can't replicate that semantic
184 * with dynamic initialization (they may have turned bits off that are
185 * set in RES_DEFAULT). Our solution is to declare such applications
186 * "broken". They could fool us by setting RES_INIT but none do (yet).
187 */
188 if (!_res.retrans)
189 _res.retrans = RES_TIMEOUT;
190 if (!_res.retry)
191 _res.retry = 4;
192 if (!(_res.options & RES_INIT))
193 _res.options = RES_DEFAULT;
194
195 /*
196 * This one used to initialize implicitly to zero, so unless the app
197 * has set it to something in particular, we can randomize it now.
198 */
199 if (!_res.id)
200 _res.id = (u_short)res_randomid();
201
202 #ifdef USELOOPBACK
203 _res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
204 #else
205 _res.nsaddr.sin_addr.s_addr = INADDR_ANY;
206 #endif
207 _res.nsaddr.sin_family = AF_INET;
208 _res.nsaddr.sin_port = htons(NAMESERVER_PORT);
209 _res.nscount = 1;
210 _res.ndots = 1;
211 _res.pfcode = 0;
212
213 /* Allow user to override the local domain definition */
214 #ifdef _ORG_FREEBSD_
215 if (issetugid() == 0 && (cp = getenv("LOCALDOMAIN")) != NULL)
216 #else
217 if ((cp = getenv("LOCALDOMAIN")) != NULL)
218 #endif
219 {
220 (void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
221 _res.defdname[sizeof(_res.defdname) - 1] = '\0';
222 haveenv++;
223
224 /*
225 * Set search list to be blank-separated strings
226 * from rest of env value. Permits users of LOCALDOMAIN
227 * to still have a search list, and anyone to set the
228 * one that they want to use as an individual (even more
229 * important now that the rfc1535 stuff restricts searches)
230 */
231 cp = _res.defdname;
232 pp = _res.dnsrch;
233 *pp++ = cp;
234 for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
235 if (*cp == '\n') /* silly backwards compat */
236 break;
237 else if (*cp == ' ' || *cp == '\t') {
238 *cp = 0;
239 n = 1;
240 } else if (n) {
241 *pp++ = cp;
242 n = 0;
243 havesearch = 1;
244 }
245 }
246 /* null terminate last domain if there are excess */
247 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
248 cp++;
249 *cp = '\0';
250 *pp++ = 0;
251 }
252
253 #define MATCH(line, name) \
254 (!strncmp(line, name, sizeof(name) - 1) && \
255 (line[sizeof(name) - 1] == ' ' || \
256 line[sizeof(name) - 1] == '\t'))
257
258 if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
259 /* read the config file */
260 while (fgets(buf, sizeof(buf), fp) != NULL) {
261 /* skip comments */
262 if (*buf == ';' || *buf == '#')
263 continue;
264 /* read default domain name */
265 if (MATCH(buf, "domain")) {
266 if (haveenv) /* skip if have from environ */
267 continue;
268 cp = buf + sizeof("domain") - 1;
269 while (*cp == ' ' || *cp == '\t')
270 cp++;
271 if ((*cp == '\0') || (*cp == '\n'))
272 continue;
273 strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
274 _res.defdname[sizeof(_res.defdname) - 1] = '\0';
275 if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)
276 *cp = '\0';
277 havesearch = 0;
278 continue;
279 }
280 /* set search list */
281 if (MATCH(buf, "search")) {
282 if (haveenv) /* skip if have from environ */
283 continue;
284 cp = buf + sizeof("search") - 1;
285 while (*cp == ' ' || *cp == '\t')
286 cp++;
287 if ((*cp == '\0') || (*cp == '\n'))
288 continue;
289 strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
290 _res.defdname[sizeof(_res.defdname) - 1] = '\0';
291 if ((cp = strchr(_res.defdname, '\n')) != NULL)
292 *cp = '\0';
293 /*
294 * Set search list to be blank-separated strings
295 * on rest of line.
296 */
297 cp = _res.defdname;
298 pp = _res.dnsrch;
299 *pp++ = cp;
300 for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
301 if (*cp == ' ' || *cp == '\t') {
302 *cp = 0;
303 n = 1;
304 } else if (n) {
305 *pp++ = cp;
306 n = 0;
307 }
308 }
309 /* null terminate last domain if there are excess */
310 while (*cp != '\0' && *cp != ' ' && *cp != '\t')
311 cp++;
312 *cp = '\0';
313 *pp++ = 0;
314 havesearch = 1;
315 continue;
316 }
317 /* read nameservers to query */
318 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
319 struct in_addr a;
320
321 cp = buf + sizeof("nameserver") - 1;
322 while (*cp == ' ' || *cp == '\t')
323 cp++;
324 if ((*cp != '\0') && (*cp != '\n') && inet_aton(cp, &a)) {
325 _res.nsaddr_list[nserv].sin_addr = a;
326 _res.nsaddr_list[nserv].sin_family = AF_INET;
327 _res.nsaddr_list[nserv].sin_port =
328 htons(NAMESERVER_PORT);
329 nserv++;
330 }
331 continue;
332 }
333 #ifdef RESOLVSORT
334 if (MATCH(buf, "sortlist")) {
335 struct in_addr a;
336
337 cp = buf + sizeof("sortlist") - 1;
338 while (nsort < MAXRESOLVSORT) {
339 while (*cp == ' ' || *cp == '\t')
340 cp++;
341 if (*cp == '\0' || *cp == '\n' || *cp == ';')
342 break;
343 net = cp;
344 while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
345 isascii(*cp) && !isspace(*cp))
346 cp++;
347 n = *cp;
348 *cp = 0;
349 if (inet_aton(net, &a)) {
350 _res.sort_list[nsort].addr = a;
351 if (ISSORTMASK(n)) {
352 *cp++ = (char)n;
353 net = cp;
354 while (*cp && *cp != ';' &&
355 isascii(*cp) && !isspace(*cp))
356 cp++;
357 n = *cp;
358 *cp = 0;
359 if (inet_aton(net, &a)) {
360 _res.sort_list[nsort].mask = a.s_addr;
361 } else {
362 _res.sort_list[nsort].mask =
363 net_mask(_res.sort_list[nsort].addr);
364 }
365 } else {
366 _res.sort_list[nsort].mask =
367 net_mask(_res.sort_list[nsort].addr);
368 }
369 nsort++;
370 }
371 *cp = (char)n;
372 }
373 continue;
374 }
375 #endif
376 if (MATCH(buf, "options")) {
377 res_setoptions(buf + sizeof("options") - 1, "conf");
378 continue;
379 }
380 }
381 if (nserv > 1)
382 _res.nscount = nserv;
383 #ifdef RESOLVSORT
384 _res.nsort = nsort;
385 #endif
386 (void) fclose(fp);
387 }
388 if (_res.defdname[0] == 0 &&
389 gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
390 (cp = strchr(buf, '.')) != NULL)
391 strcpy(_res.defdname, cp + 1);
392
393 /* find components of local domain that might be searched */
394 if (havesearch == 0) {
395 pp = _res.dnsrch;
396 *pp++ = _res.defdname;
397 *pp = NULL;
398
399 #ifndef RFC1535
400 dots = 0;
401 for (cp = _res.defdname; *cp; cp++)
402 dots += (*cp == '.');
403
404 cp = _res.defdname;
405 while (pp < _res.dnsrch + MAXDFLSRCH) {
406 if (dots < LOCALDOMAINPARTS)
407 break;
408 cp = strchr(cp, '.') + 1; /* we know there is one */
409 *pp++ = cp;
410 dots--;
411 }
412 *pp = NULL;
413 #ifdef DEBUG
414 if (_res.options & RES_DEBUG) {
415 printf(";; res_init()... default dnsrch list:\n");
416 for (pp = _res.dnsrch; *pp; pp++)
417 printf(";;\t%s\n", *pp);
418 printf(";;\t..END..\n");
419 }
420 #endif
421 #endif /* !RFC1535 */
422 }
423
424 #ifdef _ORG_FREEBSD_
425 if (issetugid())
426 #else
427 if (1)
428 #endif
429 _res.options |= RES_NOALIASES;
430 else if ((cp = getenv("RES_OPTIONS")) != NULL)
431 res_setoptions(cp, "env");
432 _res.options |= RES_INIT;
433 if ( 0 == nserv ) {
434 return -1;
435 }
436 return (0);
437 }
438
439 static void
res_setoptions(char * options,char * source)440 res_setoptions(
441 char *options,
442 char *source
443 )
444 {
445 char *cp = options;
446 int i;
447
448 #ifdef DEBUG
449 if (_res.options & RES_DEBUG)
450 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
451 options, source);
452 #endif
453 while (*cp) {
454 /* skip leading and inner runs of spaces */
455 while (*cp == ' ' || *cp == '\t')
456 cp++;
457 /* search for and process individual options */
458 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
459 i = atoi(cp + sizeof("ndots:") - 1);
460 if (i <= RES_MAXNDOTS)
461 _res.ndots = i;
462 else
463 _res.ndots = RES_MAXNDOTS;
464 #ifdef DEBUG
465 if (_res.options & RES_DEBUG)
466 printf(";;\tndots=%d\n", _res.ndots);
467 #endif
468 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
469 #ifdef DEBUG
470 if (!(_res.options & RES_DEBUG)) {
471 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
472 options, source);
473 _res.options |= RES_DEBUG;
474 }
475 printf(";;\tdebug\n");
476 #endif
477 } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
478 _res.options |= RES_USE_INET6;
479 } else if (!strncmp(cp, "no_tld_query", sizeof("no_tld_query") - 1)) {
480 _res.options |= RES_NOTLDQUERY;
481 } else {
482 /* XXX - print a warning here? */
483 }
484 /* skip to next run of spaces */
485 while (*cp && *cp != ' ' && *cp != '\t')
486 cp++;
487 }
488 }
489
490 #ifdef RESOLVSORT
491 /* XXX - should really support CIDR which means explicit masks always. */
492 static u_int32_t
net_mask(struct in_addr in)493 net_mask(
494 struct in_addr in
495 )
496 {
497 register u_int32_t i = ntohl(in.s_addr);
498
499 if (IN_CLASSA(i))
500 return (htonl(IN_CLASSA_NET));
501 else if (IN_CLASSB(i))
502 return (htonl(IN_CLASSB_NET));
503 return (htonl(IN_CLASSC_NET));
504 }
505 #endif
506
507 u_int
res_randomid()508 res_randomid()
509 {
510 struct timeval now;
511
512 gettimeofday(&now, NULL);
513 return (0xffff & (now.tv_sec ^ now.tv_usec /* ^ getpid() */));
514 }
515