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 * 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.
16 *
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.
28 */
29
30/*
31 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
32 *
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.
39 *
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.
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.
65 */
66
67#include <ctype.h>
68#include <netdb.h>
69#include <resolv/resolv-internal.h>
70#include <stdio.h>
71#include <stdio_ext.h>
72#include <stdlib.h>
73#include <string.h>
74#include <unistd.h>
75#include <stdint.h>
76#include <arpa/inet.h>
77#include <arpa/nameser.h>
78#include <net/if.h>
79#include <netinet/in.h>
80#include <sys/param.h>
81#include <sys/socket.h>
82#include <sys/time.h>
83#include <sys/types.h>
84#include <inet/net-internal.h>
85
86#include <not-cancel.h>
87
88/* Options. Should all be left alone. */
89/* #undef DEBUG */
90
91static void res_setoptions (res_state, const char *, const char *)
92 internal_function;
93
94static const char sort_mask_chars[] = "/&";
95#define ISSORTMASK(ch) (strchr(sort_mask_chars, ch) != NULL)
96static u_int32_t net_mask (struct in_addr) __THROW;
97
98unsigned long long int __res_initstamp attribute_hidden;
99
100/*
101 * Resolver state default settings.
102 */
103
104/*
105 * Set up default settings. If the configuration file exist, the values
106 * there will have precedence. Otherwise, the server address is set to
107 * INADDR_LOOPBACK and the default domain name comes from gethostname.
108 *
109 * Return 0 if completes successfully, -1 on error
110 */
111int
112res_ninit(res_state statp) {
113 extern int __res_vinit(res_state, int);
114
115 return (__res_vinit(statp, 0));
116}
117libc_hidden_def (__res_ninit)
118
119/* This function has to be reachable by res_data.c but not publically. */
120int
121__res_vinit(res_state statp, int preinit) {
122 FILE *fp;
123 char *cp, **pp;
124 int n;
125 char buf[BUFSIZ];
126 int nserv = 0; /* number of nameservers read from file */
127 int have_serv6 = 0;
128 int haveenv = 0;
129 int havesearch = 0;
130 int nsort = 0;
131 char *net;
132 statp->_u._ext.initstamp = __res_initstamp;
133
134 if (!preinit) {
135 statp->retrans = RES_TIMEOUT;
136 statp->retry = RES_DFLRETRY;
137 statp->options = RES_DEFAULT;
138 statp->id = res_randomid();
139 }
140
141 statp->nscount = 0;
142 statp->defdname[0] = '\0';
143 statp->ndots = 1;
144 statp->pfcode = 0;
145 statp->_vcsock = -1;
146 statp->_flags = 0;
147 statp->__glibc_unused_qhook = NULL;
148 statp->__glibc_unused_rhook = NULL;
149 statp->_u._ext.nscount = 0;
150 for (n = 0; n < MAXNS; n++)
151 statp->_u._ext.nsaddrs[n] = NULL;
152
153 /* Allow user to override the local domain definition */
154 if ((cp = getenv("LOCALDOMAIN")) != NULL) {
155 (void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
156 statp->defdname[sizeof(statp->defdname) - 1] = '\0';
157 haveenv++;
158
159 /*
160 * Set search list to be blank-separated strings
161 * from rest of env value. Permits users of LOCALDOMAIN
162 * to still have a search list, and anyone to set the
163 * one that they want to use as an individual (even more
164 * important now that the rfc1535 stuff restricts searches)
165 */
166 cp = statp->defdname;
167 pp = statp->dnsrch;
168 *pp++ = cp;
169 for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
170 if (*cp == '\n') /* silly backwards compat */
171 break;
172 else if (*cp == ' ' || *cp == '\t') {
173 *cp = 0;
174 n = 1;
175 } else if (n) {
176 *pp++ = cp;
177 n = 0;
178 havesearch = 1;
179 }
180 }
181 /* null terminate last domain if there are excess */
182 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
183 cp++;
184 *cp = '\0';
185 *pp++ = 0;
186 }
187
188#define MATCH(line, name) \
189 (!strncmp(line, name, sizeof(name) - 1) && \
190 (line[sizeof(name) - 1] == ' ' || \
191 line[sizeof(name) - 1] == '\t'))
192
193 if ((fp = fopen(_PATH_RESCONF, "rce")) != NULL) {
194 /* No threads use this stream. */
195 __fsetlocking (fp, FSETLOCKING_BYCALLER);
196 /* read the config file */
197 while (__fgets_unlocked(buf, sizeof(buf), fp) != NULL) {
198 /* skip comments */
199 if (*buf == ';' || *buf == '#')
200 continue;
201 /* read default domain name */
202 if (MATCH(buf, "domain")) {
203 if (haveenv) /* skip if have from environ */
204 continue;
205 cp = buf + sizeof("domain") - 1;
206 while (*cp == ' ' || *cp == '\t')
207 cp++;
208 if ((*cp == '\0') || (*cp == '\n'))
209 continue;
210 strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
211 statp->defdname[sizeof(statp->defdname) - 1] = '\0';
212 if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
213 *cp = '\0';
214 havesearch = 0;
215 continue;
216 }
217 /* set search list */
218 if (MATCH(buf, "search")) {
219 if (haveenv) /* skip if have from environ */
220 continue;
221 cp = buf + sizeof("search") - 1;
222 while (*cp == ' ' || *cp == '\t')
223 cp++;
224 if ((*cp == '\0') || (*cp == '\n'))
225 continue;
226 strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
227 statp->defdname[sizeof(statp->defdname) - 1] = '\0';
228 if ((cp = strchr(statp->defdname, '\n')) != NULL)
229 *cp = '\0';
230 /*
231 * Set search list to be blank-separated strings
232 * on rest of line.
233 */
234 cp = statp->defdname;
235 pp = statp->dnsrch;
236 *pp++ = cp;
237 for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
238 if (*cp == ' ' || *cp == '\t') {
239 *cp = 0;
240 n = 1;
241 } else if (n) {
242 *pp++ = cp;
243 n = 0;
244 }
245 }
246 /* null terminate last domain if there are excess */
247 while (*cp != '\0' && *cp != ' ' && *cp != '\t')
248 cp++;
249 *cp = '\0';
250 *pp++ = 0;
251 havesearch = 1;
252 continue;
253 }
254 /* read nameservers to query */
255 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
256 struct in_addr a;
257
258 cp = buf + sizeof("nameserver") - 1;
259 while (*cp == ' ' || *cp == '\t')
260 cp++;
261 if ((*cp != '\0') && (*cp != '\n')
262 && __inet_aton(cp, &a)) {
263 statp->nsaddr_list[nserv].sin_addr = a;
264 statp->nsaddr_list[nserv].sin_family = AF_INET;
265 statp->nsaddr_list[nserv].sin_port =
266 htons(NAMESERVER_PORT);
267 nserv++;
268 } else {
269 struct in6_addr a6;
270 char *el;
271
272 if ((el = strpbrk(cp, " \t\n")) != NULL)
273 *el = '\0';
274 if ((el = strchr(cp, SCOPE_DELIMITER)) != NULL)
275 *el = '\0';
276 if ((*cp != '\0') &&
277 (__inet_pton(AF_INET6, cp, &a6) > 0)) {
278 struct sockaddr_in6 *sa6;
279
280 sa6 = malloc(sizeof(*sa6));
281 if (sa6 != NULL) {
282 sa6->sin6_family = AF_INET6;
283 sa6->sin6_port = htons(NAMESERVER_PORT);
284 sa6->sin6_flowinfo = 0;
285 sa6->sin6_addr = a6;
286
287 sa6->sin6_scope_id = 0;
288 if (__glibc_likely (el != NULL)) {
289 /* Ignore errors, for backwards
290 compatibility. */
291 (void) __inet6_scopeid_pton
292 (&a6, el + 1, &sa6->sin6_scope_id);
293 }
294
295 statp->nsaddr_list[nserv].sin_family = 0;
296 statp->_u._ext.nsaddrs[nserv] = sa6;
297 statp->_u._ext.nssocks[nserv] = -1;
298 have_serv6 = 1;
299 nserv++;
300 }
301 }
302 }
303 continue;
304 }
305 if (MATCH(buf, "sortlist")) {
306 struct in_addr a;
307
308 cp = buf + sizeof("sortlist") - 1;
309 while (nsort < MAXRESOLVSORT) {
310 while (*cp == ' ' || *cp == '\t')
311 cp++;
312 if (*cp == '\0' || *cp == '\n' || *cp == ';')
313 break;
314 net = cp;
315 while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
316 isascii(*cp) && !isspace(*cp))
317 cp++;
318 n = *cp;
319 *cp = 0;
320 if (__inet_aton(net, &a)) {
321 statp->sort_list[nsort].addr = a;
322 if (ISSORTMASK(n)) {
323 *cp++ = n;
324 net = cp;
325 while (*cp && *cp != ';' &&
326 isascii(*cp) && !isspace(*cp))
327 cp++;
328 n = *cp;
329 *cp = 0;
330 if (__inet_aton(net, &a)) {
331 statp->sort_list[nsort].mask = a.s_addr;
332 } else {
333 statp->sort_list[nsort].mask =
334 net_mask(statp->sort_list[nsort].addr);
335 }
336 } else {
337 statp->sort_list[nsort].mask =
338 net_mask(statp->sort_list[nsort].addr);
339 }
340 nsort++;
341 }
342 *cp = n;
343 }
344 continue;
345 }
346 if (MATCH(buf, "options")) {
347 res_setoptions(statp, buf + sizeof("options") - 1, "conf");
348 continue;
349 }
350 }
351 statp->nscount = nserv;
352 if (have_serv6) {
353 /* We try IPv6 servers again. */
354 statp->ipv6_unavail = false;
355 }
356 statp->nsort = nsort;
357 (void) fclose(fp);
358 }
359 if (__builtin_expect(statp->nscount == 0, 0)) {
360 statp->nsaddr.sin_addr = __inet_makeaddr(IN_LOOPBACKNET, 1);
361 statp->nsaddr.sin_family = AF_INET;
362 statp->nsaddr.sin_port = htons(NAMESERVER_PORT);
363 statp->nscount = 1;
364 }
365 if (statp->defdname[0] == 0 &&
366 __gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
367 (cp = strchr(buf, '.')) != NULL)
368 strcpy(statp->defdname, cp + 1);
369
370 /* find components of local domain that might be searched */
371 if (havesearch == 0) {
372 pp = statp->dnsrch;
373 *pp++ = statp->defdname;
374 *pp = NULL;
375
376 }
377
378 if ((cp = getenv("RES_OPTIONS")) != NULL)
379 res_setoptions(statp, cp, "env");
380 statp->options |= RES_INIT;
381 return (0);
382}
383
384static void
385internal_function
386res_setoptions(res_state statp, const char *options, const char *source) {
387 const char *cp = options;
388 int i;
389
390#ifdef DEBUG
391 if (statp->options & RES_DEBUG)
392 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
393 options, source);
394#endif
395 while (*cp) {
396 /* skip leading and inner runs of spaces */
397 while (*cp == ' ' || *cp == '\t')
398 cp++;
399 /* search for and process individual options */
400 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
401 i = atoi(cp + sizeof("ndots:") - 1);
402 if (i <= RES_MAXNDOTS)
403 statp->ndots = i;
404 else
405 statp->ndots = RES_MAXNDOTS;
406#ifdef DEBUG
407 if (statp->options & RES_DEBUG)
408 printf(";;\tndots=%d\n", statp->ndots);
409#endif
410 } else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
411 i = atoi(cp + sizeof("timeout:") - 1);
412 if (i <= RES_MAXRETRANS)
413 statp->retrans = i;
414 else
415 statp->retrans = RES_MAXRETRANS;
416 } else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
417 i = atoi(cp + sizeof("attempts:") - 1);
418 if (i <= RES_MAXRETRY)
419 statp->retry = i;
420 else
421 statp->retry = RES_MAXRETRY;
422 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
423#ifdef DEBUG
424 if (!(statp->options & RES_DEBUG)) {
425 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
426 options, source);
427 statp->options |= RES_DEBUG;
428 }
429 printf(";;\tdebug\n");
430#endif
431 } else {
432 static const struct
433 {
434 char str[22];
435 uint8_t len;
436 uint8_t clear;
437 unsigned long int flag;
438 } options[] = {
439#define STRnLEN(str) str, sizeof (str) - 1
440 { STRnLEN ("inet6"), 0, DEPRECATED_RES_USE_INET6 },
441 { STRnLEN ("rotate"), 0, RES_ROTATE },
442 { STRnLEN ("edns0"), 0, RES_USE_EDNS0 },
443 { STRnLEN ("single-request-reopen"), 0, RES_SNGLKUPREOP },
444 { STRnLEN ("single-request"), 0, RES_SNGLKUP },
445 { STRnLEN ("no_tld_query"), 0, RES_NOTLDQUERY },
446 { STRnLEN ("no-tld-query"), 0, RES_NOTLDQUERY },
447 { STRnLEN ("use-vc"), 0, RES_USEVC }
448 };
449#define noptions (sizeof (options) / sizeof (options[0]))
450 int i;
451 for (i = 0; i < noptions; ++i)
452 if (strncmp (cp, options[i].str, options[i].len) == 0)
453 {
454 if (options[i].clear)
455 statp->options &= options[i].flag;
456 else
457 statp->options |= options[i].flag;
458 break;
459 }
460 if (i == noptions) {
461 /* XXX - print a warning here? */
462 }
463 }
464 /* skip to next run of spaces */
465 while (*cp && *cp != ' ' && *cp != '\t')
466 cp++;
467 }
468}
469
470/* XXX - should really support CIDR which means explicit masks always. */
471/* XXX - should really use system's version of this */
472static u_int32_t
473net_mask (struct in_addr in)
474{
475 u_int32_t i = ntohl(in.s_addr);
476
477 if (IN_CLASSA(i))
478 return (htonl(IN_CLASSA_NET));
479 else if (IN_CLASSB(i))
480 return (htonl(IN_CLASSB_NET));
481 return (htonl(IN_CLASSC_NET));
482}
483
484u_int
485res_randomid(void) {
486 return 0xffff & __getpid();
487}
488libc_hidden_def (__res_randomid)
489
490
491/*
492 * This routine is for closing the socket if a virtual circuit is used and
493 * the program wants to close it. This provides support for endhostent()
494 * which expects to close the socket.
495 *
496 * This routine is not expected to be user visible.
497 */
498void
499__res_iclose(res_state statp, bool free_addr) {
500 int ns;
501
502 if (statp->_vcsock >= 0) {
503 close_not_cancel_no_status(statp->_vcsock);
504 statp->_vcsock = -1;
505 statp->_flags &= ~(RES_F_VC | RES_F_CONN);
506 }
507 for (ns = 0; ns < statp->nscount; ns++)
508 if (statp->_u._ext.nsaddrs[ns]) {
509 if (statp->_u._ext.nssocks[ns] != -1) {
510 close_not_cancel_no_status(statp->_u._ext.nssocks[ns]);
511 statp->_u._ext.nssocks[ns] = -1;
512 }
513 if (free_addr) {
514 free (statp->_u._ext.nsaddrs[ns]);
515 statp->_u._ext.nsaddrs[ns] = NULL;
516 }
517 }
518}
519libc_hidden_def (__res_iclose)
520
521void
522res_nclose(res_state statp)
523{
524 __res_iclose (statp, true);
525}
526libc_hidden_def (__res_nclose)
527
528/* This is called when a thread is exiting to free resources held in _res. */
529static void __attribute__ ((section ("__libc_thread_freeres_fn")))
530res_thread_freeres (void)
531{
532 if (_res.nscount == 0)
533 /* Never called res_ninit. */
534 return;
535
536 __res_iclose (&_res, true); /* Close any VC sockets. */
537
538 /* Make sure we do a full re-initialization the next time. */
539 _res.options = 0;
540}
541text_set_element (__libc_thread_subfreeres, res_thread_freeres);
542text_set_element (__libc_subfreeres, res_thread_freeres);
543