xref: /netbsd-src/lib/libc/resolv/res_init.c (revision 466a16a118933bd295a8a104f095714fadf9cf68)
1 /*	$NetBSD: res_init.c,v 1.15 2008/06/21 23:37:53 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1985, 1989, 1993
5  *    The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  * 	This product includes software developed by the University of
18  * 	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 /*
37  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
38  *
39  * Permission to use, copy, modify, and distribute this software for any
40  * purpose with or without fee is hereby granted, provided that the above
41  * copyright notice and this permission notice appear in all copies, and that
42  * the name of Digital Equipment Corporation not be used in advertising or
43  * publicity pertaining to distribution of the document or software without
44  * specific, written prior permission.
45  *
46  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
47  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
48  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
49  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
50  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
51  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
52  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
53  * SOFTWARE.
54  */
55 
56 /*
57  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
58  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
59  *
60  * Permission to use, copy, modify, and distribute this software for any
61  * purpose with or without fee is hereby granted, provided that the above
62  * copyright notice and this permission notice appear in all copies.
63  *
64  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
65  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
66  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
67  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
68  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
69  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
70  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
71  */
72 
73 #include <sys/cdefs.h>
74 #if defined(LIBC_SCCS) && !defined(lint)
75 #ifdef notdef
76 static const char sccsid[] = "@(#)res_init.c	8.1 (Berkeley) 6/7/93";
77 static const char rcsid[] = "Id: res_init.c,v 1.23 2007/07/09 01:43:23 marka Exp";
78 #else
79 __RCSID("$NetBSD: res_init.c,v 1.15 2008/06/21 23:37:53 christos Exp $");
80 #endif
81 #endif /* LIBC_SCCS and not lint */
82 
83 #include "port_before.h"
84 
85 #include "namespace.h"
86 #include <sys/types.h>
87 #include <sys/param.h>
88 #include <sys/socket.h>
89 #include <sys/time.h>
90 
91 #include <netinet/in.h>
92 #include <arpa/inet.h>
93 #include <arpa/nameser.h>
94 
95 #include <ctype.h>
96 #include <stdio.h>
97 #include <stdlib.h>
98 #include <string.h>
99 #include <unistd.h>
100 #include <netdb.h>
101 
102 #include "port_after.h"
103 
104 #if 0
105 #ifdef __weak_alias
106 __weak_alias(res_ninit,_res_ninit)
107 __weak_alias(res_randomid,__res_randomid)
108 __weak_alias(res_nclose,_res_nclose)
109 __weak_alias(res_ndestroy,_res_ndestroy)
110 __weak_alias(res_get_nibblesuffix,__res_get_nibblesuffix)
111 __weak_alias(res_get_nibblesuffix2,__res_get_nibblesuffix2)
112 __weak_alias(res_getservers,__res_getservers)
113 __weak_alias(res_setservers,__res_setservers)
114 #endif
115 #endif
116 
117 
118 /* ensure that sockaddr_in6 and IN6ADDR_ANY_INIT are declared / defined */
119 #include <resolv.h>
120 
121 #include "res_private.h"
122 
123 #define RESOLVSORT
124 /*% Options.  Should all be left alone. */
125 #ifndef DEBUG
126 #define DEBUG
127 #endif
128 
129 #ifdef SOLARIS2
130 #include <sys/systeminfo.h>
131 #endif
132 
133 static void res_setoptions __P((res_state, const char *, const char *));
134 
135 #ifdef RESOLVSORT
136 static const char sort_mask[] = "/&";
137 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
138 static u_int32_t net_mask __P((struct in_addr));
139 #endif
140 
141 #if !defined(isascii)	/*%< XXX - could be a function */
142 # define isascii(c) (!(c & 0200))
143 #endif
144 
145 /*
146  * Resolver state default settings.
147  */
148 
149 /*%
150  * Set up default settings.  If the configuration file exist, the values
151  * there will have precedence.  Otherwise, the server address is set to
152  * INADDR_ANY and the default domain name comes from the gethostname().
153  *
154  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
155  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
156  * since it was noted that INADDR_ANY actually meant ``the first interface
157  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
158  * it had to be "up" in order for you to reach your own name server.  It
159  * was later decided that since the recommended practice is to always
160  * install local static routes through 127.0.0.1 for all your network
161  * interfaces, that we could solve this problem without a code change.
162  *
163  * The configuration file should always be used, since it is the only way
164  * to specify a default domain.  If you are running a server on your local
165  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
166  * in the configuration file.
167  *
168  * Return 0 if completes successfully, -1 on error
169  */
170 int
171 res_ninit(res_state statp) {
172 	extern int __res_vinit(res_state, int);
173 
174 	return (__res_vinit(statp, 0));
175 }
176 
177 /*% This function has to be reachable by res_data.c but not publically. */
178 int
179 __res_vinit(res_state statp, int preinit) {
180 	register FILE *fp;
181 	register char *cp, **pp;
182 	register int n;
183 	char buf[BUFSIZ];
184 	int nserv = 0;    /*%< number of nameserver records read from file */
185 	int haveenv = 0;
186 	int havesearch = 0;
187 #ifdef RESOLVSORT
188 	int nsort = 0;
189 	char *net;
190 #endif
191 	int dots;
192 	union res_sockaddr_union u[2];
193 
194 	int maxns = MAXNS;
195 
196 	RES_SET_H_ERRNO(statp, 0);
197 
198 	if (!preinit) {
199 		statp->retrans = RES_TIMEOUT;
200 		statp->retry = RES_DFLRETRY;
201 		statp->options = RES_DEFAULT;
202 		statp->id = res_randomid();
203 	}
204 
205 	if ((statp->options & RES_INIT) != 0U)
206 		res_ndestroy(statp);
207 
208 	memset(u, 0, sizeof(u));
209 #ifdef USELOOPBACK
210 	u[nserv].sin.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
211 #else
212 	u[nserv].sin.sin_addr.s_addr = INADDR_ANY;
213 #endif
214 	u[nserv].sin.sin_family = AF_INET;
215 	u[nserv].sin.sin_port = htons(NAMESERVER_PORT);
216 #ifdef HAVE_SA_LEN
217 	u[nserv].sin.sin_len = sizeof(struct sockaddr_in);
218 #endif
219 	nserv++;
220 #ifdef HAS_INET6_STRUCTS
221 #ifdef USELOOPBACK
222 	u[nserv].sin6.sin6_addr = in6addr_loopback;
223 #else
224 	u[nserv].sin6.sin6_addr = in6addr_any;
225 #endif
226 	u[nserv].sin6.sin6_family = AF_INET6;
227 	u[nserv].sin6.sin6_port = htons(NAMESERVER_PORT);
228 #ifdef HAVE_SA_LEN
229 	u[nserv].sin6.sin6_len = sizeof(struct sockaddr_in6);
230 #endif
231 	nserv++;
232 #endif
233 	statp->nscount = 0;
234 	statp->ndots = 1;
235 	statp->pfcode = 0;
236 	statp->_vcsock = -1;
237 	statp->_flags = 0;
238 	statp->qhook = NULL;
239 	statp->rhook = NULL;
240 	statp->_u._ext.nscount = 0;
241 	statp->_u._ext.ext = malloc(sizeof(*statp->_u._ext.ext));
242 	if (statp->_u._ext.ext != NULL) {
243 	        memset(statp->_u._ext.ext, 0, sizeof(*statp->_u._ext.ext));
244 		statp->_u._ext.ext->nsaddrs[0].sin = statp->nsaddr;
245 		strcpy(statp->_u._ext.ext->nsuffix, "ip6.arpa");
246 		strcpy(statp->_u._ext.ext->nsuffix2, "ip6.int");
247 	} else {
248 		/*
249 		 * Historically res_init() rarely, if at all, failed.
250 		 * Examples and applications exist which do not check
251 		 * our return code.  Furthermore several applications
252 		 * simply call us to get the systems domainname.  So
253 		 * rather then immediately fail here we store the
254 		 * failure, which is returned later, in h_errno.  And
255 		 * prevent the collection of 'nameserver' information
256 		 * by setting maxns to 0.  Thus applications that fail
257 		 * to check our return code wont be able to make
258 		 * queries anyhow.
259 		 */
260 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
261 		maxns = 0;
262 	}
263 #ifdef RESOLVSORT
264 	statp->nsort = 0;
265 #endif
266 	res_setservers(statp, u, nserv);
267 
268 #ifdef	SOLARIS2
269 	/*
270 	 * The old libresolv derived the defaultdomain from NIS/NIS+.
271 	 * We want to keep this behaviour
272 	 */
273 	{
274 		char buf[sizeof(statp->defdname)], *cp;
275 		int ret;
276 
277 		if ((ret = sysinfo(SI_SRPC_DOMAIN, buf, sizeof(buf))) > 0 &&
278 			(unsigned int)ret <= sizeof(buf)) {
279 			if (buf[0] == '+')
280 				buf[0] = '.';
281 			cp = strchr(buf, '.');
282 			cp = (cp == NULL) ? buf : (cp + 1);
283 			(void)strlcpy(statp->defdname, cp,
284 			    sizeof(statp->defdname));
285 		}
286 	}
287 #endif	/* SOLARIS2 */
288 
289 	/* Allow user to override the local domain definition */
290 	if ((cp = getenv("LOCALDOMAIN")) != NULL) {
291 		(void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
292 		statp->defdname[sizeof(statp->defdname) - 1] = '\0';
293 		haveenv++;
294 
295 		/*
296 		 * Set search list to be blank-separated strings
297 		 * from rest of env value.  Permits users of LOCALDOMAIN
298 		 * to still have a search list, and anyone to set the
299 		 * one that they want to use as an individual (even more
300 		 * important now that the rfc1535 stuff restricts searches)
301 		 */
302 		cp = statp->defdname;
303 		pp = statp->dnsrch;
304 		*pp++ = cp;
305 		for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
306 			if (*cp == '\n')	/*%< silly backwards compat */
307 				break;
308 			else if (*cp == ' ' || *cp == '\t') {
309 				*cp = 0;
310 				n = 1;
311 			} else if (n) {
312 				*pp++ = cp;
313 				n = 0;
314 				havesearch = 1;
315 			}
316 		}
317 		/* null terminate last domain if there are excess */
318 		while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
319 			cp++;
320 		*cp = '\0';
321 		*pp++ = 0;
322 	}
323 
324 #define	MATCH(line, name) \
325 	(!strncmp(line, name, sizeof(name) - 1) && \
326 	(line[sizeof(name) - 1] == ' ' || \
327 	 line[sizeof(name) - 1] == '\t'))
328 
329 	nserv = 0;
330 	if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
331 	    /* read the config file */
332 	    while (fgets(buf, sizeof(buf), fp) != NULL) {
333 		/* skip comments */
334 		if (*buf == ';' || *buf == '#')
335 			continue;
336 		/* read default domain name */
337 		if (MATCH(buf, "domain")) {
338 		    if (haveenv)	/*%< skip if have from environ */
339 			    continue;
340 		    cp = buf + sizeof("domain") - 1;
341 		    while (*cp == ' ' || *cp == '\t')
342 			    cp++;
343 		    if ((*cp == '\0') || (*cp == '\n'))
344 			    continue;
345 		    strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
346 		    statp->defdname[sizeof(statp->defdname) - 1] = '\0';
347 		    if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
348 			    *cp = '\0';
349 		    havesearch = 0;
350 		    continue;
351 		}
352 		/* set search list */
353 		if (MATCH(buf, "search")) {
354 		    if (haveenv)	/*%< skip if have from environ */
355 			    continue;
356 		    cp = buf + sizeof("search") - 1;
357 		    while (*cp == ' ' || *cp == '\t')
358 			    cp++;
359 		    if ((*cp == '\0') || (*cp == '\n'))
360 			    continue;
361 		    strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
362 		    statp->defdname[sizeof(statp->defdname) - 1] = '\0';
363 		    if ((cp = strchr(statp->defdname, '\n')) != NULL)
364 			    *cp = '\0';
365 		    /*
366 		     * Set search list to be blank-separated strings
367 		     * on rest of line.
368 		     */
369 		    cp = statp->defdname;
370 		    pp = statp->dnsrch;
371 		    *pp++ = cp;
372 		    for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
373 			    if (*cp == ' ' || *cp == '\t') {
374 				    *cp = 0;
375 				    n = 1;
376 			    } else if (n) {
377 				    *pp++ = cp;
378 				    n = 0;
379 			    }
380 		    }
381 		    /* null terminate last domain if there are excess */
382 		    while (*cp != '\0' && *cp != ' ' && *cp != '\t')
383 			    cp++;
384 		    *cp = '\0';
385 		    *pp++ = 0;
386 		    havesearch = 1;
387 		    continue;
388 		}
389 		/* read nameservers to query */
390 		if (MATCH(buf, "nameserver") && nserv < maxns) {
391 		    struct addrinfo hints, *ai;
392 		    char sbuf[NI_MAXSERV];
393 		    const size_t minsiz =
394 		        sizeof(statp->_u._ext.ext->nsaddrs[0]);
395 
396 		    cp = buf + sizeof("nameserver") - 1;
397 		    while (*cp == ' ' || *cp == '\t')
398 			cp++;
399 		    cp[strcspn(cp, ";# \t\n")] = '\0';
400 		    if ((*cp != '\0') && (*cp != '\n')) {
401 			memset(&hints, 0, sizeof(hints));
402 			hints.ai_family = PF_UNSPEC;
403 			hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
404 			hints.ai_flags = AI_NUMERICHOST;
405 			sprintf(sbuf, "%u", NAMESERVER_PORT);
406 			if (getaddrinfo(cp, sbuf, &hints, &ai) == 0 &&
407 			    ai->ai_addrlen <= minsiz) {
408 			    if (statp->_u._ext.ext != NULL) {
409 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
410 				    ai->ai_addr, ai->ai_addrlen);
411 			    }
412 			    if (ai->ai_addrlen <=
413 			        sizeof(statp->nsaddr_list[nserv])) {
414 				memcpy(&statp->nsaddr_list[nserv],
415 				    ai->ai_addr, ai->ai_addrlen);
416 			    } else
417 				statp->nsaddr_list[nserv].sin_family = 0;
418 			    freeaddrinfo(ai);
419 			    nserv++;
420 			}
421 		    }
422 		    continue;
423 		}
424 #ifdef RESOLVSORT
425 		if (MATCH(buf, "sortlist")) {
426 		    struct in_addr a;
427 
428 		    cp = buf + sizeof("sortlist") - 1;
429 		    while (nsort < MAXRESOLVSORT) {
430 			while (*cp == ' ' || *cp == '\t')
431 			    cp++;
432 			if (*cp == '\0' || *cp == '\n' || *cp == ';')
433 			    break;
434 			net = cp;
435 			while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
436 			       isascii(*cp) && !isspace((unsigned char)*cp))
437 				cp++;
438 			n = *cp;
439 			*cp = 0;
440 			if (inet_aton(net, &a)) {
441 			    statp->sort_list[nsort].addr = a;
442 			    if (ISSORTMASK(n)) {
443 				*cp++ = n;
444 				net = cp;
445 				while (*cp && *cp != ';' &&
446 					isascii(*cp) &&
447 					!isspace((unsigned char)*cp))
448 				    cp++;
449 				n = *cp;
450 				*cp = 0;
451 				if (inet_aton(net, &a)) {
452 				    statp->sort_list[nsort].mask = a.s_addr;
453 				} else {
454 				    statp->sort_list[nsort].mask =
455 					net_mask(statp->sort_list[nsort].addr);
456 				}
457 			    } else {
458 				statp->sort_list[nsort].mask =
459 				    net_mask(statp->sort_list[nsort].addr);
460 			    }
461 			    nsort++;
462 			}
463 			*cp = n;
464 		    }
465 		    continue;
466 		}
467 #endif
468 		if (MATCH(buf, "options")) {
469 		    res_setoptions(statp, buf + sizeof("options") - 1, "conf");
470 		    continue;
471 		}
472 	    }
473 	    if (nserv > 0)
474 		statp->nscount = nserv;
475 #ifdef RESOLVSORT
476 	    statp->nsort = nsort;
477 #endif
478 	    (void) fclose(fp);
479 	}
480 /*
481  * Last chance to get a nameserver.  This should not normally
482  * be necessary
483  */
484 #ifdef NO_RESOLV_CONF
485 	if(nserv == 0)
486 		nserv = get_nameservers(statp);
487 #endif
488 
489 	if (statp->defdname[0] == 0 &&
490 	    gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
491 	    (cp = strchr(buf, '.')) != NULL)
492 		strcpy(statp->defdname, cp + 1);
493 
494 	/* find components of local domain that might be searched */
495 	if (havesearch == 0) {
496 		pp = statp->dnsrch;
497 		*pp++ = statp->defdname;
498 		*pp = NULL;
499 
500 		dots = 0;
501 		for (cp = statp->defdname; *cp; cp++)
502 			dots += (*cp == '.');
503 
504 		cp = statp->defdname;
505 		while (pp < statp->dnsrch + MAXDFLSRCH) {
506 			if (dots < LOCALDOMAINPARTS)
507 				break;
508 			cp = strchr(cp, '.') + 1;    /*%< we know there is one */
509 			*pp++ = cp;
510 			dots--;
511 		}
512 		*pp = NULL;
513 #ifdef DEBUG
514 		if (statp->options & RES_DEBUG) {
515 			printf(";; res_init()... default dnsrch list:\n");
516 			for (pp = statp->dnsrch; *pp; pp++)
517 				printf(";;\t%s\n", *pp);
518 			printf(";;\t..END..\n");
519 		}
520 #endif
521 	}
522 
523 	if ((cp = getenv("RES_OPTIONS")) != NULL)
524 		res_setoptions(statp, cp, "env");
525 	statp->options |= RES_INIT;
526 
527 	return (statp->res_h_errno);
528 }
529 
530 static void
531 res_setoptions(res_state statp, const char *options, const char *source)
532 {
533 	const char *cp = options;
534 	int i;
535 	struct __res_state_ext *ext = statp->_u._ext.ext;
536 
537 #ifdef DEBUG
538 	if (statp->options & RES_DEBUG)
539 		printf(";; res_setoptions(\"%s\", \"%s\")...\n",
540 		       options, source);
541 #endif
542 	while (*cp) {
543 		/* skip leading and inner runs of spaces */
544 		while (*cp == ' ' || *cp == '\t')
545 			cp++;
546 		/* search for and process individual options */
547 		if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
548 			i = atoi(cp + sizeof("ndots:") - 1);
549 			if (i <= RES_MAXNDOTS)
550 				statp->ndots = i;
551 			else
552 				statp->ndots = RES_MAXNDOTS;
553 #ifdef DEBUG
554 			if (statp->options & RES_DEBUG)
555 				printf(";;\tndots=%d\n", statp->ndots);
556 #endif
557 		} else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
558 			i = atoi(cp + sizeof("timeout:") - 1);
559 			if (i <= RES_MAXRETRANS)
560 				statp->retrans = i;
561 			else
562 				statp->retrans = RES_MAXRETRANS;
563 #ifdef DEBUG
564 			if (statp->options & RES_DEBUG)
565 				printf(";;\ttimeout=%d\n", statp->retrans);
566 #endif
567 #ifdef	SOLARIS2
568 		} else if (!strncmp(cp, "retrans:", sizeof("retrans:") - 1)) {
569 			/*
570 		 	 * For backward compatibility, 'retrans' is
571 		 	 * supported as an alias for 'timeout', though
572 		 	 * without an imposed maximum.
573 		 	 */
574 			statp->retrans = atoi(cp + sizeof("retrans:") - 1);
575 		} else if (!strncmp(cp, "retry:", sizeof("retry:") - 1)){
576 			/*
577 			 * For backward compatibility, 'retry' is
578 			 * supported as an alias for 'attempts', though
579 			 * without an imposed maximum.
580 			 */
581 			statp->retry = atoi(cp + sizeof("retry:") - 1);
582 #endif	/* SOLARIS2 */
583 		} else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
584 			i = atoi(cp + sizeof("attempts:") - 1);
585 			if (i <= RES_MAXRETRY)
586 				statp->retry = i;
587 			else
588 				statp->retry = RES_MAXRETRY;
589 #ifdef DEBUG
590 			if (statp->options & RES_DEBUG)
591 				printf(";;\tattempts=%d\n", statp->retry);
592 #endif
593 		} else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
594 #ifdef DEBUG
595 			if (!(statp->options & RES_DEBUG)) {
596 				printf(";; res_setoptions(\"%s\", \"%s\")..\n",
597 				       options, source);
598 				statp->options |= RES_DEBUG;
599 			}
600 			printf(";;\tdebug\n");
601 #endif
602 		} else if (!strncmp(cp, "no_tld_query",
603 				    sizeof("no_tld_query") - 1) ||
604 			   !strncmp(cp, "no-tld-query",
605 				    sizeof("no-tld-query") - 1)) {
606 			statp->options |= RES_NOTLDQUERY;
607 		} else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
608 			statp->options |= RES_USE_INET6;
609 		} else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
610 			statp->options |= RES_ROTATE;
611 		} else if (!strncmp(cp, "no-check-names",
612 				    sizeof("no-check-names") - 1)) {
613 			statp->options |= RES_NOCHECKNAME;
614 		}
615 #ifdef RES_USE_EDNS0
616 		else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
617 			statp->options |= RES_USE_EDNS0;
618 		}
619 #endif
620 		else if (!strncmp(cp, "dname", sizeof("dname") - 1)) {
621 			statp->options |= RES_USE_DNAME;
622 		}
623 		else if (!strncmp(cp, "nibble:", sizeof("nibble:") - 1)) {
624 			if (ext == NULL)
625 				goto skip;
626 			cp += sizeof("nibble:") - 1;
627 			i = MIN(strcspn(cp, " \t"), sizeof(ext->nsuffix) - 1);
628 			strncpy(ext->nsuffix, cp, (size_t)i);
629 			ext->nsuffix[i] = '\0';
630 		}
631 		else if (!strncmp(cp, "nibble2:", sizeof("nibble2:") - 1)) {
632 			if (ext == NULL)
633 				goto skip;
634 			cp += sizeof("nibble2:") - 1;
635 			i = MIN(strcspn(cp, " \t"), sizeof(ext->nsuffix2) - 1);
636 			strncpy(ext->nsuffix2, cp, (size_t)i);
637 			ext->nsuffix2[i] = '\0';
638 		}
639 		else if (!strncmp(cp, "v6revmode:", sizeof("v6revmode:") - 1)) {
640 			cp += sizeof("v6revmode:") - 1;
641 			/* "nibble" and "bitstring" used to be valid */
642 			if (!strncmp(cp, "single", sizeof("single") - 1)) {
643 				statp->options |= RES_NO_NIBBLE2;
644 			} else if (!strncmp(cp, "both", sizeof("both") - 1)) {
645 				statp->options &=
646 					 ~RES_NO_NIBBLE2;
647 			}
648 		}
649 		else {
650 			/* XXX - print a warning here? */
651 		}
652    skip:
653 		/* skip to next run of spaces */
654 		while (*cp && *cp != ' ' && *cp != '\t')
655 			cp++;
656 	}
657 }
658 
659 #ifdef RESOLVSORT
660 /* XXX - should really support CIDR which means explicit masks always. */
661 static u_int32_t
662 net_mask(in)		/*!< XXX - should really use system's version of this  */
663 	struct in_addr in;
664 {
665 	register u_int32_t i = ntohl(in.s_addr);
666 
667 	if (IN_CLASSA(i))
668 		return (htonl(IN_CLASSA_NET));
669 	else if (IN_CLASSB(i))
670 		return (htonl(IN_CLASSB_NET));
671 	return (htonl(IN_CLASSC_NET));
672 }
673 #endif
674 
675 u_int
676 res_randomid(void) {
677 	struct timeval now;
678 
679 	gettimeofday(&now, NULL);
680 	return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
681 }
682 
683 /*%
684  * This routine is for closing the socket if a virtual circuit is used and
685  * the program wants to close it.  This provides support for endhostent()
686  * which expects to close the socket.
687  *
688  * This routine is not expected to be user visible.
689  */
690 void
691 res_nclose(res_state statp) {
692 	int ns;
693 
694 	if (statp->_vcsock >= 0) {
695 		(void) close(statp->_vcsock);
696 		statp->_vcsock = -1;
697 		statp->_flags &= ~(RES_F_VC | RES_F_CONN);
698 	}
699 	for (ns = 0; ns < statp->_u._ext.nscount; ns++) {
700 		if (statp->_u._ext.nssocks[ns] != -1) {
701 			(void) close(statp->_u._ext.nssocks[ns]);
702 			statp->_u._ext.nssocks[ns] = -1;
703 		}
704 	}
705 }
706 
707 void
708 res_ndestroy(res_state statp) {
709 	res_nclose(statp);
710 	if (statp->_u._ext.ext != NULL)
711 		free(statp->_u._ext.ext);
712 	statp->options &= ~RES_INIT;
713 	statp->_u._ext.ext = NULL;
714 }
715 
716 const char *
717 res_get_nibblesuffix(res_state statp) {
718 	if (statp->_u._ext.ext)
719 		return (statp->_u._ext.ext->nsuffix);
720 	return ("ip6.arpa");
721 }
722 
723 const char *
724 res_get_nibblesuffix2(res_state statp) {
725 	if (statp->_u._ext.ext)
726 		return (statp->_u._ext.ext->nsuffix2);
727 	return ("ip6.int");
728 }
729 
730 void
731 res_setservers(res_state statp, const union res_sockaddr_union *set, int cnt) {
732 	int i, nserv;
733 	size_t size;
734 
735 	/* close open servers */
736 	res_nclose(statp);
737 
738 	/* cause rtt times to be forgotten */
739 	statp->_u._ext.nscount = 0;
740 
741 	nserv = 0;
742 	for (i = 0; i < cnt && nserv < MAXNS; i++) {
743 		switch (set->sin.sin_family) {
744 		case AF_INET:
745 			size = sizeof(set->sin);
746 			if (statp->_u._ext.ext)
747 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
748 					&set->sin, size);
749 			if (size <= sizeof(statp->nsaddr_list[nserv]))
750 				memcpy(&statp->nsaddr_list[nserv],
751 					&set->sin, size);
752 			else
753 				statp->nsaddr_list[nserv].sin_family = 0;
754 			nserv++;
755 			break;
756 
757 #ifdef HAS_INET6_STRUCTS
758 		case AF_INET6:
759 			size = sizeof(set->sin6);
760 			if (statp->_u._ext.ext)
761 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
762 					&set->sin6, size);
763 			if (size <= sizeof(statp->nsaddr_list[nserv]))
764 				memcpy(&statp->nsaddr_list[nserv],
765 					&set->sin6, size);
766 			else
767 				statp->nsaddr_list[nserv].sin_family = 0;
768 			nserv++;
769 			break;
770 #endif
771 
772 		default:
773 			break;
774 		}
775 		set++;
776 	}
777 	statp->nscount = nserv;
778 
779 }
780 
781 int
782 res_getservers(res_state statp, union res_sockaddr_union *set, int cnt) {
783 	int i;
784 	size_t size;
785 	u_int16_t family;
786 
787 	for (i = 0; i < statp->nscount && i < cnt; i++) {
788 		if (statp->_u._ext.ext)
789 			family = statp->_u._ext.ext->nsaddrs[i].sin.sin_family;
790 		else
791 			family = statp->nsaddr_list[i].sin_family;
792 
793 		switch (family) {
794 		case AF_INET:
795 			size = sizeof(set->sin);
796 			if (statp->_u._ext.ext)
797 				memcpy(&set->sin,
798 				       &statp->_u._ext.ext->nsaddrs[i],
799 				       size);
800 			else
801 				memcpy(&set->sin, &statp->nsaddr_list[i],
802 				       size);
803 			break;
804 
805 #ifdef HAS_INET6_STRUCTS
806 		case AF_INET6:
807 			size = sizeof(set->sin6);
808 			if (statp->_u._ext.ext)
809 				memcpy(&set->sin6,
810 				       &statp->_u._ext.ext->nsaddrs[i],
811 				       size);
812 			else
813 				memcpy(&set->sin6, &statp->nsaddr_list[i],
814 				       size);
815 			break;
816 #endif
817 
818 		default:
819 			set->sin.sin_family = 0;
820 			break;
821 		}
822 		set++;
823 	}
824 	return (statp->nscount);
825 }
826 
827 /*! \file */
828