2 * Copyright (c) 1985, 1989, 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
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.
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
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24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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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
33 * @(#)res_init.c 8.1 (Berkeley) 6/7/93
34 * $From: Id: res_init.c,v 8.7 1996/11/18 09:10:04 vixie Exp $
35 * $FreeBSD: src/lib/libc/net/res_init.c,v 1.19.2.7 2002/02/04 18:30:55 ume Exp $
36 * $DragonFly: src/lib/libcr/net/Attic/res_init.c,v 1.4 2004/10/25 19:38:25 drhodus Exp $
40 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
42 * Permission to use, copy, modify, and distribute this software for any
43 * purpose with or without fee is hereby granted, provided that the above
44 * copyright notice and this permission notice appear in all copies, and that
45 * the name of Digital Equipment Corporation not be used in advertising or
46 * publicity pertaining to distribution of the document or software without
47 * specific, written prior permission.
49 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
50 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
51 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
52 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
53 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
54 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
55 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
60 * Portions Copyright (c) 1996 by Internet Software Consortium.
62 * Permission to use, copy, modify, and distribute this software for any
63 * purpose with or without fee is hereby granted, provided that the above
64 * copyright notice and this permission notice appear in all copies.
66 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
67 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
68 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
69 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
70 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
71 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
72 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
76 #include <sys/types.h>
77 #include <sys/param.h>
78 #include <sys/socket.h>
80 #include <netinet/in.h>
81 #include <arpa/inet.h>
82 #include <arpa/nameser.h>
91 #include "res_config.h"
93 static void res_setoptions (char *, char *);
96 static const char sort_mask[] = "/&";
97 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
98 static u_int32_t net_mask (struct in_addr);
101 #if !defined(isascii) /* XXX - could be a function */
102 # define isascii(c) (!(c & 0200))
106 * Resolver state default settings.
109 struct __res_state _res
110 # if defined(__BIND_RES_TEXT)
111 = { RES_TIMEOUT, } /* Motorola, et al. */
115 struct __res_state_ext _res_ext;
118 * Set up default settings. If the configuration file exist, the values
119 * there will have precedence. Otherwise, the server address is set to
120 * INADDR_ANY and the default domain name comes from the gethostname().
122 * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
123 * rather than INADDR_ANY ("0.0.0.0") as the default name server address
124 * since it was noted that INADDR_ANY actually meant ``the first interface
125 * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
126 * it had to be "up" in order for you to reach your own name server. It
127 * was later decided that since the recommended practice is to always
128 * install local static routes through 127.0.0.1 for all your network
129 * interfaces, that we could solve this problem without a code change.
131 * The configuration file should always be used, since it is the only way
132 * to specify a default domain. If you are running a server on your local
133 * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
134 * in the configuration file.
136 * Return 0 if completes successfully, -1 on error
145 int nserv = 0; /* number of nameserver records read from file */
157 * These three fields used to be statically initialized. This made
158 * it hard to use this code in a shared library. It is necessary,
159 * now that we're doing dynamic initialization here, that we preserve
160 * the old semantics: if an application modifies one of these three
161 * fields of _res before res_init() is called, res_init() will not
162 * alter them. Of course, if an application is setting them to
163 * _zero_ before calling res_init(), hoping to override what used
164 * to be the static default, we can't detect it and unexpected results
165 * will follow. Zero for any of these fields would make no sense,
166 * so one can safely assume that the applications were already getting
167 * unexpected results.
169 * _res.options is tricky since some apps were known to diddle the bits
170 * before res_init() was first called. We can't replicate that semantic
171 * with dynamic initialization (they may have turned bits off that are
172 * set in RES_DEFAULT). Our solution is to declare such applications
173 * "broken". They could fool us by setting RES_INIT but none do (yet).
176 _res.retrans = RES_TIMEOUT;
179 if (!(_res.options & RES_INIT))
180 _res.options = RES_DEFAULT;
183 * This one used to initialize implicitly to zero, so unless the app
184 * has set it to something in particular, we can randomize it now.
187 _res.id = res_randomid();
190 _res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
192 _res.nsaddr.sin_addr.s_addr = INADDR_ANY;
194 _res.nsaddr.sin_family = AF_INET;
195 _res.nsaddr.sin_port = htons(NAMESERVER_PORT);
196 _res.nsaddr.sin_len = sizeof(struct sockaddr_in);
197 if (sizeof(_res_ext.nsaddr) >= _res.nsaddr.sin_len)
198 memcpy(&_res_ext.nsaddr, &_res.nsaddr, _res.nsaddr.sin_len);
203 /* Allow user to override the local domain definition */
204 if (issetugid() == 0 && (cp = getenv("LOCALDOMAIN")) != NULL) {
205 (void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
206 _res.defdname[sizeof(_res.defdname) - 1] = '\0';
210 * Set search list to be blank-separated strings
211 * from rest of env value. Permits users of LOCALDOMAIN
212 * to still have a search list, and anyone to set the
213 * one that they want to use as an individual (even more
214 * important now that the rfc1535 stuff restricts searches)
219 for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
220 if (*cp == '\n') /* silly backwards compat */
222 else if (*cp == ' ' || *cp == '\t') {
231 /* null terminate last domain if there are excess */
232 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
238 #define MATCH(line, name) \
239 (!strncmp(line, name, sizeof(name) - 1) && \
240 (line[sizeof(name) - 1] == ' ' || \
241 line[sizeof(name) - 1] == '\t'))
243 if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
244 /* read the config file */
245 while (fgets(buf, sizeof(buf), fp) != NULL) {
247 if (*buf == ';' || *buf == '#')
249 /* read default domain name */
250 if (MATCH(buf, "domain")) {
251 if (haveenv) /* skip if have from environ */
253 cp = buf + sizeof("domain") - 1;
254 while (*cp == ' ' || *cp == '\t')
256 if ((*cp == '\0') || (*cp == '\n'))
258 strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
259 _res.defdname[sizeof(_res.defdname) - 1] = '\0';
260 if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)
265 /* set search list */
266 if (MATCH(buf, "search")) {
267 if (haveenv) /* skip if have from environ */
269 cp = buf + sizeof("search") - 1;
270 while (*cp == ' ' || *cp == '\t')
272 if ((*cp == '\0') || (*cp == '\n'))
274 strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
275 _res.defdname[sizeof(_res.defdname) - 1] = '\0';
276 if ((cp = strchr(_res.defdname, '\n')) != NULL)
279 * Set search list to be blank-separated strings
285 for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
286 if (*cp == ' ' || *cp == '\t') {
294 /* null terminate last domain if there are excess */
295 while (*cp != '\0' && *cp != ' ' && *cp != '\t')
302 /* read nameservers to query */
303 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
305 struct addrinfo hints, *res;
306 char pbuf[NI_MAXSERV];
308 cp = buf + sizeof("nameserver") - 1;
309 while (*cp == ' ' || *cp == '\t')
311 if ((*cp == '\0') || (*cp == '\n'))
313 for (q = cp; *q; q++) {
319 memset(&hints, 0, sizeof(hints));
320 hints.ai_flags = AI_NUMERICHOST;
321 hints.ai_socktype = SOCK_DGRAM;
322 snprintf(pbuf, sizeof(pbuf), "%d", NAMESERVER_PORT);
323 if (getaddrinfo(cp, pbuf, &hints, &res) == 0 &&
324 res->ai_next == NULL) {
325 if (res->ai_addrlen <= sizeof(_res_ext.nsaddr_list[nserv])) {
326 memcpy(&_res_ext.nsaddr_list[nserv], res->ai_addr,
329 memset(&_res_ext.nsaddr_list[nserv], 0,
330 sizeof(_res_ext.nsaddr_list[nserv]));
332 if (res->ai_addrlen <= sizeof(_res.nsaddr_list[nserv])) {
333 memcpy(&_res.nsaddr_list[nserv], res->ai_addr,
336 memset(&_res.nsaddr_list[nserv], 0,
337 sizeof(_res.nsaddr_list[nserv]));
346 if (MATCH(buf, "sortlist")) {
352 cp = buf + sizeof("sortlist") - 1;
353 while (nsort < MAXRESOLVSORT) {
354 while (*cp == ' ' || *cp == '\t')
356 if (*cp == '\0' || *cp == '\n' || *cp == ';')
359 while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
360 isascii(*cp) && !isspace(*cp))
364 if (inet_aton(net, &a)) {
365 _res.sort_list[nsort].addr = a;
369 while (*cp && *cp != ';' &&
370 isascii(*cp) && !isspace(*cp))
374 if (inet_aton(net, &a)) {
375 _res.sort_list[nsort].mask = a.s_addr;
377 _res.sort_list[nsort].mask =
378 net_mask(_res.sort_list[nsort].addr);
381 _res.sort_list[nsort].mask =
382 net_mask(_res.sort_list[nsort].addr);
384 _res_ext.sort_list[nsort].af = AF_INET;
385 _res_ext.sort_list[nsort].addr.ina =
386 _res.sort_list[nsort].addr;
387 _res_ext.sort_list[nsort].mask.ina.s_addr =
388 _res.sort_list[nsort].mask;
391 else if (inet_pton(AF_INET6, net, &a6) == 1) {
393 _res_ext.sort_list[nsort].af = AF_INET6;
394 _res_ext.sort_list[nsort].addr.in6a = a6;
395 u = (u_char *)&_res_ext.sort_list[nsort].mask.in6a;
398 while (*cp && *cp != ';' &&
399 isascii(*cp) && !isspace(*cp))
409 if (inet_pton(AF_INET6, net, u) == 1) {
415 m = sizeof(struct in6_addr) * NBBY;
419 for (i = 0; i < sizeof(struct in6_addr); i++) {
431 _res.sort_list[nsort].addr.s_addr =
432 (u_int32_t)0xffffffff;
433 _res.sort_list[nsort].mask = (u_int32_t)0xffffffff;
441 if (MATCH(buf, "options")) {
442 res_setoptions(buf + sizeof("options") - 1, "conf");
447 _res.nscount = nserv;
453 if (_res.defdname[0] == 0 &&
454 gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
455 (cp = strchr(buf, '.')) != NULL)
456 strcpy(_res.defdname, cp + 1);
458 /* find components of local domain that might be searched */
459 if (havesearch == 0) {
461 *pp++ = _res.defdname;
466 for (cp = _res.defdname; *cp; cp++)
467 dots += (*cp == '.');
470 while (pp < _res.dnsrch + MAXDFLSRCH) {
471 if (dots < LOCALDOMAINPARTS)
473 cp = strchr(cp, '.') + 1; /* we know there is one */
479 if (_res.options & RES_DEBUG) {
480 printf(";; res_init()... default dnsrch list:\n");
481 for (pp = _res.dnsrch; *pp; pp++)
482 printf(";;\t%s\n", *pp);
483 printf(";;\t..END..\n");
486 #endif /* !RFC1535 */
490 _res.options |= RES_NOALIASES;
491 else if ((cp = getenv("RES_OPTIONS")) != NULL)
492 res_setoptions(cp, "env");
493 _res.options |= RES_INIT;
498 res_setoptions(options, source)
499 char *options, *source;
505 if (_res.options & RES_DEBUG)
506 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
510 /* skip leading and inner runs of spaces */
511 while (*cp == ' ' || *cp == '\t')
513 /* search for and process individual options */
514 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
515 i = atoi(cp + sizeof("ndots:") - 1);
516 if (i <= RES_MAXNDOTS)
519 _res.ndots = RES_MAXNDOTS;
521 if (_res.options & RES_DEBUG)
522 printf(";;\tndots=%d\n", _res.ndots);
524 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
526 if (!(_res.options & RES_DEBUG)) {
527 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
529 _res.options |= RES_DEBUG;
531 printf(";;\tdebug\n");
533 } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
534 _res.options |= RES_USE_INET6;
535 } else if (!strncmp(cp, "insecure1", sizeof("insecure1") - 1)) {
536 _res.options |= RES_INSECURE1;
537 } else if (!strncmp(cp, "insecure2", sizeof("insecure2") - 1)) {
538 _res.options |= RES_INSECURE2;
539 } else if (!strncmp(cp, "no_tld_query", sizeof("no_tld_query") - 1)) {
540 _res.options |= RES_NOTLDQUERY;
541 } else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
542 _res.options |= RES_USE_EDNS0;
544 /* XXX - print a warning here? */
546 /* skip to next run of spaces */
547 while (*cp && *cp != ' ' && *cp != '\t')
553 /* XXX - should really support CIDR which means explicit masks always. */
555 net_mask(in) /* XXX - should really use system's version of this */
558 u_int32_t i = ntohl(in.s_addr);
561 return (htonl(IN_CLASSA_NET));
562 else if (IN_CLASSB(i))
563 return (htonl(IN_CLASSB_NET));
564 return (htonl(IN_CLASSC_NET));
573 gettimeofday(&now, NULL);
574 return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
578 * Weak aliases for applications that use certain private entry points,
579 * and fail to include <resolv.h>.
582 __weak_reference(__res_init, res_init);