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. 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.
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
29 * @(#)res_init.c 8.1 (Berkeley) 6/7/93
30 * $From: Id: res_init.c,v 8.7 1996/11/18 09:10:04 vixie Exp $
31 * $FreeBSD: src/lib/libc/net/res_init.c,v 1.19.2.7 2002/02/04 18:30:55 ume Exp $
32 * $DragonFly: src/lib/libc/net/res_init.c,v 1.6 2005/11/13 02:04:47 swildner Exp $
36 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
38 * Permission to use, copy, modify, and distribute this software for any
39 * purpose with or without fee is hereby granted, provided that the above
40 * copyright notice and this permission notice appear in all copies, and that
41 * the name of Digital Equipment Corporation not be used in advertising or
42 * publicity pertaining to distribution of the document or software without
43 * specific, written prior permission.
45 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
46 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
47 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
48 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
49 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
50 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
51 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
56 * Portions Copyright (c) 1996 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
63 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
64 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
65 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
66 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
67 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
68 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
72 #include <sys/types.h>
73 #include <sys/param.h>
74 #include <sys/socket.h>
76 #include <netinet/in.h>
77 #include <arpa/inet.h>
78 #include <arpa/nameser.h>
87 #include "res_config.h"
89 static void res_setoptions (char *, char *);
92 static const char sort_mask[] = "/&";
93 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
94 static u_int32_t net_mask (struct in_addr);
97 #if !defined(isascii) /* XXX - could be a function */
98 # define isascii(c) (!(c & 0200))
102 * Resolver state default settings.
105 struct __res_state _res
106 # if defined(__BIND_RES_TEXT)
107 = { RES_TIMEOUT, } /* Motorola, et al. */
111 struct __res_state_ext _res_ext;
114 * Set up default settings. If the configuration file exist, the values
115 * there will have precedence. Otherwise, the server address is set to
116 * INADDR_ANY and the default domain name comes from the gethostname().
118 * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
119 * rather than INADDR_ANY ("0.0.0.0") as the default name server address
120 * since it was noted that INADDR_ANY actually meant ``the first interface
121 * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
122 * it had to be "up" in order for you to reach your own name server. It
123 * was later decided that since the recommended practice is to always
124 * install local static routes through 127.0.0.1 for all your network
125 * interfaces, that we could solve this problem without a code change.
127 * The configuration file should always be used, since it is the only way
128 * to specify a default domain. If you are running a server on your local
129 * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
130 * in the configuration file.
132 * Return 0 if completes successfully, -1 on error
141 int nserv = 0; /* number of nameserver records read from file */
153 * These three fields used to be statically initialized. This made
154 * it hard to use this code in a shared library. It is necessary,
155 * now that we're doing dynamic initialization here, that we preserve
156 * the old semantics: if an application modifies one of these three
157 * fields of _res before res_init() is called, res_init() will not
158 * alter them. Of course, if an application is setting them to
159 * _zero_ before calling res_init(), hoping to override what used
160 * to be the static default, we can't detect it and unexpected results
161 * will follow. Zero for any of these fields would make no sense,
162 * so one can safely assume that the applications were already getting
163 * unexpected results.
165 * _res.options is tricky since some apps were known to diddle the bits
166 * before res_init() was first called. We can't replicate that semantic
167 * with dynamic initialization (they may have turned bits off that are
168 * set in RES_DEFAULT). Our solution is to declare such applications
169 * "broken". They could fool us by setting RES_INIT but none do (yet).
172 _res.retrans = RES_TIMEOUT;
175 if (!(_res.options & RES_INIT))
176 _res.options = RES_DEFAULT;
179 * This one used to initialize implicitly to zero, so unless the app
180 * has set it to something in particular, we can randomize it now.
183 _res.id = res_randomid();
186 _res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
188 _res.nsaddr.sin_addr.s_addr = INADDR_ANY;
190 _res.nsaddr.sin_family = AF_INET;
191 _res.nsaddr.sin_port = htons(NAMESERVER_PORT);
192 _res.nsaddr.sin_len = sizeof(struct sockaddr_in);
193 if (sizeof(_res_ext.nsaddr) >= _res.nsaddr.sin_len)
194 memcpy(&_res_ext.nsaddr, &_res.nsaddr, _res.nsaddr.sin_len);
199 /* Allow user to override the local domain definition */
200 if (issetugid() == 0 && (cp = getenv("LOCALDOMAIN")) != NULL) {
201 strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
202 _res.defdname[sizeof(_res.defdname) - 1] = '\0';
206 * Set search list to be blank-separated strings
207 * from rest of env value. Permits users of LOCALDOMAIN
208 * to still have a search list, and anyone to set the
209 * one that they want to use as an individual (even more
210 * important now that the rfc1535 stuff restricts searches)
215 for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
216 if (*cp == '\n') /* silly backwards compat */
218 else if (*cp == ' ' || *cp == '\t') {
227 /* null terminate last domain if there are excess */
228 while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
234 #define MATCH(line, name) \
235 (!strncmp(line, name, sizeof(name) - 1) && \
236 (line[sizeof(name) - 1] == ' ' || \
237 line[sizeof(name) - 1] == '\t'))
239 if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
240 /* read the config file */
241 while (fgets(buf, sizeof(buf), fp) != NULL) {
243 if (*buf == ';' || *buf == '#')
245 /* read default domain name */
246 if (MATCH(buf, "domain")) {
247 if (haveenv) /* skip if have from environ */
249 cp = buf + sizeof("domain") - 1;
250 while (*cp == ' ' || *cp == '\t')
252 if ((*cp == '\0') || (*cp == '\n'))
254 strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
255 _res.defdname[sizeof(_res.defdname) - 1] = '\0';
256 if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL)
261 /* set search list */
262 if (MATCH(buf, "search")) {
263 if (haveenv) /* skip if have from environ */
265 cp = buf + sizeof("search") - 1;
266 while (*cp == ' ' || *cp == '\t')
268 if ((*cp == '\0') || (*cp == '\n'))
270 strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1);
271 _res.defdname[sizeof(_res.defdname) - 1] = '\0';
272 if ((cp = strchr(_res.defdname, '\n')) != NULL)
275 * Set search list to be blank-separated strings
281 for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) {
282 if (*cp == ' ' || *cp == '\t') {
290 /* null terminate last domain if there are excess */
291 while (*cp != '\0' && *cp != ' ' && *cp != '\t')
298 /* read nameservers to query */
299 if (MATCH(buf, "nameserver") && nserv < MAXNS) {
301 struct addrinfo hints, *res;
302 char pbuf[NI_MAXSERV];
304 cp = buf + sizeof("nameserver") - 1;
305 while (*cp == ' ' || *cp == '\t')
307 if ((*cp == '\0') || (*cp == '\n'))
309 for (q = cp; *q; q++) {
315 memset(&hints, 0, sizeof(hints));
316 hints.ai_flags = AI_NUMERICHOST;
317 hints.ai_socktype = SOCK_DGRAM;
318 snprintf(pbuf, sizeof(pbuf), "%d", NAMESERVER_PORT);
319 if (getaddrinfo(cp, pbuf, &hints, &res) == 0 &&
320 res->ai_next == NULL) {
321 if (res->ai_addrlen <= sizeof(_res_ext.nsaddr_list[nserv])) {
322 memcpy(&_res_ext.nsaddr_list[nserv], res->ai_addr,
325 memset(&_res_ext.nsaddr_list[nserv], 0,
326 sizeof(_res_ext.nsaddr_list[nserv]));
328 if (res->ai_addrlen <= sizeof(_res.nsaddr_list[nserv])) {
329 memcpy(&_res.nsaddr_list[nserv], res->ai_addr,
332 memset(&_res.nsaddr_list[nserv], 0,
333 sizeof(_res.nsaddr_list[nserv]));
342 if (MATCH(buf, "sortlist")) {
348 cp = buf + sizeof("sortlist") - 1;
349 while (nsort < MAXRESOLVSORT) {
350 while (*cp == ' ' || *cp == '\t')
352 if (*cp == '\0' || *cp == '\n' || *cp == ';')
355 while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
356 isascii(*cp) && !isspace(*cp))
360 if (inet_aton(net, &a)) {
361 _res.sort_list[nsort].addr = a;
365 while (*cp && *cp != ';' &&
366 isascii(*cp) && !isspace(*cp))
370 if (inet_aton(net, &a)) {
371 _res.sort_list[nsort].mask = a.s_addr;
373 _res.sort_list[nsort].mask =
374 net_mask(_res.sort_list[nsort].addr);
377 _res.sort_list[nsort].mask =
378 net_mask(_res.sort_list[nsort].addr);
380 _res_ext.sort_list[nsort].af = AF_INET;
381 _res_ext.sort_list[nsort].addr.ina =
382 _res.sort_list[nsort].addr;
383 _res_ext.sort_list[nsort].mask.ina.s_addr =
384 _res.sort_list[nsort].mask;
387 else if (inet_pton(AF_INET6, net, &a6) == 1) {
389 _res_ext.sort_list[nsort].af = AF_INET6;
390 _res_ext.sort_list[nsort].addr.in6a = a6;
391 u = (u_char *)&_res_ext.sort_list[nsort].mask.in6a;
394 while (*cp && *cp != ';' &&
395 isascii(*cp) && !isspace(*cp))
405 if (inet_pton(AF_INET6, net, u) == 1) {
411 m = sizeof(struct in6_addr) * NBBY;
415 for (i = 0; i < sizeof(struct in6_addr); i++) {
427 _res.sort_list[nsort].addr.s_addr =
428 (u_int32_t)0xffffffff;
429 _res.sort_list[nsort].mask = (u_int32_t)0xffffffff;
437 if (MATCH(buf, "options")) {
438 res_setoptions(buf + sizeof("options") - 1, "conf");
443 _res.nscount = nserv;
449 if (_res.defdname[0] == 0 &&
450 gethostname(buf, sizeof(_res.defdname) - 1) == 0 &&
451 (cp = strchr(buf, '.')) != NULL)
452 strcpy(_res.defdname, cp + 1);
454 /* find components of local domain that might be searched */
455 if (havesearch == 0) {
457 *pp++ = _res.defdname;
462 for (cp = _res.defdname; *cp; cp++)
463 dots += (*cp == '.');
466 while (pp < _res.dnsrch + MAXDFLSRCH) {
467 if (dots < LOCALDOMAINPARTS)
469 cp = strchr(cp, '.') + 1; /* we know there is one */
475 if (_res.options & RES_DEBUG) {
476 printf(";; res_init()... default dnsrch list:\n");
477 for (pp = _res.dnsrch; *pp; pp++)
478 printf(";;\t%s\n", *pp);
479 printf(";;\t..END..\n");
482 #endif /* !RFC1535 */
486 _res.options |= RES_NOALIASES;
487 else if ((cp = getenv("RES_OPTIONS")) != NULL)
488 res_setoptions(cp, "env");
489 _res.options |= RES_INIT;
494 res_setoptions(char *options, char *source)
500 if (_res.options & RES_DEBUG)
501 printf(";; res_setoptions(\"%s\", \"%s\")...\n",
505 /* skip leading and inner runs of spaces */
506 while (*cp == ' ' || *cp == '\t')
508 /* search for and process individual options */
509 if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
510 i = atoi(cp + sizeof("ndots:") - 1);
511 if (i <= RES_MAXNDOTS)
514 _res.ndots = RES_MAXNDOTS;
516 if (_res.options & RES_DEBUG)
517 printf(";;\tndots=%d\n", _res.ndots);
519 } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
521 if (!(_res.options & RES_DEBUG)) {
522 printf(";; res_setoptions(\"%s\", \"%s\")..\n",
524 _res.options |= RES_DEBUG;
526 printf(";;\tdebug\n");
528 } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
529 _res.options |= RES_USE_INET6;
530 } else if (!strncmp(cp, "insecure1", sizeof("insecure1") - 1)) {
531 _res.options |= RES_INSECURE1;
532 } else if (!strncmp(cp, "insecure2", sizeof("insecure2") - 1)) {
533 _res.options |= RES_INSECURE2;
534 } else if (!strncmp(cp, "no_tld_query", sizeof("no_tld_query") - 1)) {
535 _res.options |= RES_NOTLDQUERY;
536 } else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
537 _res.options |= RES_USE_EDNS0;
539 /* XXX - print a warning here? */
541 /* skip to next run of spaces */
542 while (*cp && *cp != ' ' && *cp != '\t')
548 /* XXX - should really support CIDR which means explicit masks always. */
550 net_mask(struct in_addr in) /* XXX - should really use system's version of this */
552 u_int32_t i = ntohl(in.s_addr);
555 return (htonl(IN_CLASSA_NET));
556 else if (IN_CLASSB(i))
557 return (htonl(IN_CLASSB_NET));
558 return (htonl(IN_CLASSC_NET));
567 gettimeofday(&now, NULL);
568 return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
572 * Weak aliases for applications that use certain private entry points,
573 * and fail to include <resolv.h>.
576 __weak_reference(__res_init, res_init);