xref: /netbsd-src/lib/libc/resolv/res_init.c (revision d48f14661dda8638fee055ba15d35bdfb29b9fa8)
1 /*	$NetBSD: res_init.c,v 1.8 2006/03/19 03:10:08 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 1.9.2.5.4.2 2004/03/16 12:34:18 marka Exp";
78 #else
79 __RCSID("$NetBSD: res_init.c,v 1.8 2006/03/19 03:10:08 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 /* Options.  Should all be left alone. */
124 #ifndef DEBUG
125 #define DEBUG
126 #endif
127 
128 static void res_setoptions __P((res_state, const char *, const char *));
129 
130 static const char sort_mask[] = "/&";
131 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
132 static u_int32_t net_mask __P((struct in_addr));
133 
134 #if !defined(isascii)	/* XXX - could be a function */
135 # define isascii(c) (!(c & 0200))
136 #endif
137 
138 /*
139  * Resolver state default settings.
140  */
141 
142 /*
143  * Set up default settings.  If the configuration file exist, the values
144  * there will have precedence.  Otherwise, the server address is set to
145  * INADDR_ANY and the default domain name comes from the gethostname().
146  *
147  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
148  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
149  * since it was noted that INADDR_ANY actually meant ``the first interface
150  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
151  * it had to be "up" in order for you to reach your own name server.  It
152  * was later decided that since the recommended practice is to always
153  * install local static routes through 127.0.0.1 for all your network
154  * interfaces, that we could solve this problem without a code change.
155  *
156  * The configuration file should always be used, since it is the only way
157  * to specify a default domain.  If you are running a server on your local
158  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
159  * in the configuration file.
160  *
161  * Return 0 if completes successfully, -1 on error
162  */
163 int
164 res_ninit(res_state statp) {
165 	extern int __res_vinit(res_state, int);
166 
167 	return (__res_vinit(statp, 0));
168 }
169 
170 /* This function has to be reachable by res_data.c but not publically. */
171 int
172 __res_vinit(res_state statp, int preinit) {
173 	register FILE *fp;
174 	register char *cp, **pp;
175 	register int n;
176 	char buf[BUFSIZ];
177 	int nserv = 0;    /* number of nameserver records read from file */
178 	int haveenv = 0;
179 	int havesearch = 0;
180 	int nsort = 0;
181 	char *net;
182 	int dots;
183 	union res_sockaddr_union u[2];
184 
185 	if (!preinit) {
186 		statp->retrans = RES_TIMEOUT;
187 		statp->retry = RES_DFLRETRY;
188 		statp->options = RES_DEFAULT;
189 		statp->id = res_randomid();
190 	}
191 
192 	if ((statp->options & RES_INIT) != 0U)
193 		res_ndestroy(statp);
194 
195 	memset(u, 0, sizeof(u));
196 #ifdef USELOOPBACK
197 	u[nserv].sin.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
198 #else
199 	u[nserv].sin.sin_addr.s_addr = INADDR_ANY;
200 #endif
201 	u[nserv].sin.sin_family = AF_INET;
202 	u[nserv].sin.sin_port = htons(NAMESERVER_PORT);
203 #ifdef HAVE_SA_LEN
204 	u[nserv].sin.sin_len = sizeof(struct sockaddr_in);
205 #endif
206 	nserv++;
207 #ifdef HAS_INET6_STRUCTS
208 #ifdef USELOOPBACK
209 	u[nserv].sin6.sin6_addr = in6addr_loopback;
210 #else
211 	u[nserv].sin6.sin6_addr = in6addr_any;
212 #endif
213 	u[nserv].sin6.sin6_family = AF_INET6;
214 	u[nserv].sin6.sin6_port = htons(NAMESERVER_PORT);
215 #ifdef HAVE_SA_LEN
216 	u[nserv].sin6.sin6_len = sizeof(struct sockaddr_in6);
217 #endif
218 	nserv++;
219 #endif
220 	statp->nscount = 0;
221 	statp->ndots = 1;
222 	statp->pfcode = 0;
223 	statp->_vcsock = -1;
224 	statp->_flags = 0;
225 	statp->qhook = NULL;
226 	statp->rhook = NULL;
227 	statp->_u._ext.nscount = 0;
228 	statp->_u._ext.ext = malloc(sizeof(*statp->_u._ext.ext));
229 	if (statp->_u._ext.ext != NULL) {
230 	        memset(statp->_u._ext.ext, 0, sizeof(*statp->_u._ext.ext));
231 		statp->_u._ext.ext->nsaddrs[0].sin = statp->nsaddr;
232 		strcpy(statp->_u._ext.ext->nsuffix, "ip6.arpa");
233 		strcpy(statp->_u._ext.ext->nsuffix2, "ip6.int");
234 	}
235 	statp->nsort = 0;
236 	res_setservers(statp, u, nserv);
237 
238 	/* Allow user to override the local domain definition */
239 	if ((cp = getenv("LOCALDOMAIN")) != NULL) {
240 		(void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
241 		statp->defdname[sizeof(statp->defdname) - 1] = '\0';
242 		haveenv++;
243 
244 		/*
245 		 * Set search list to be blank-separated strings
246 		 * from rest of env value.  Permits users of LOCALDOMAIN
247 		 * to still have a search list, and anyone to set the
248 		 * one that they want to use as an individual (even more
249 		 * important now that the rfc1535 stuff restricts searches)
250 		 */
251 		cp = statp->defdname;
252 		pp = statp->dnsrch;
253 		*pp++ = cp;
254 		for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
255 			if (*cp == '\n')	/* silly backwards compat */
256 				break;
257 			else if (*cp == ' ' || *cp == '\t') {
258 				*cp = 0;
259 				n = 1;
260 			} else if (n) {
261 				*pp++ = cp;
262 				n = 0;
263 				havesearch = 1;
264 			}
265 		}
266 		/* null terminate last domain if there are excess */
267 		while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
268 			cp++;
269 		*cp = '\0';
270 		*pp++ = 0;
271 	}
272 
273 #define	MATCH(line, name) \
274 	(!strncmp(line, name, sizeof(name) - 1) && \
275 	(line[sizeof(name) - 1] == ' ' || \
276 	 line[sizeof(name) - 1] == '\t'))
277 
278 	nserv = 0;
279 	if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
280 	    /* read the config file */
281 	    while (fgets(buf, sizeof(buf), fp) != NULL) {
282 		/* skip comments */
283 		if (*buf == ';' || *buf == '#')
284 			continue;
285 		/* read default domain name */
286 		if (MATCH(buf, "domain")) {
287 		    if (haveenv)	/* skip if have from environ */
288 			    continue;
289 		    cp = buf + sizeof("domain") - 1;
290 		    while (*cp == ' ' || *cp == '\t')
291 			    cp++;
292 		    if ((*cp == '\0') || (*cp == '\n'))
293 			    continue;
294 		    strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
295 		    statp->defdname[sizeof(statp->defdname) - 1] = '\0';
296 		    if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
297 			    *cp = '\0';
298 		    havesearch = 0;
299 		    continue;
300 		}
301 		/* set search list */
302 		if (MATCH(buf, "search")) {
303 		    if (haveenv)	/* skip if have from environ */
304 			    continue;
305 		    cp = buf + sizeof("search") - 1;
306 		    while (*cp == ' ' || *cp == '\t')
307 			    cp++;
308 		    if ((*cp == '\0') || (*cp == '\n'))
309 			    continue;
310 		    strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
311 		    statp->defdname[sizeof(statp->defdname) - 1] = '\0';
312 		    if ((cp = strchr(statp->defdname, '\n')) != NULL)
313 			    *cp = '\0';
314 		    /*
315 		     * Set search list to be blank-separated strings
316 		     * on rest of line.
317 		     */
318 		    cp = statp->defdname;
319 		    pp = statp->dnsrch;
320 		    *pp++ = cp;
321 		    for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
322 			    if (*cp == ' ' || *cp == '\t') {
323 				    *cp = 0;
324 				    n = 1;
325 			    } else if (n) {
326 				    *pp++ = cp;
327 				    n = 0;
328 			    }
329 		    }
330 		    /* null terminate last domain if there are excess */
331 		    while (*cp != '\0' && *cp != ' ' && *cp != '\t')
332 			    cp++;
333 		    *cp = '\0';
334 		    *pp++ = 0;
335 		    havesearch = 1;
336 		    continue;
337 		}
338 		/* read nameservers to query */
339 		if (MATCH(buf, "nameserver") && nserv < MAXNS) {
340 		    struct addrinfo hints, *ai;
341 		    char sbuf[NI_MAXSERV];
342 		    const size_t minsiz =
343 		        sizeof(statp->_u._ext.ext->nsaddrs[0]);
344 
345 		    cp = buf + sizeof("nameserver") - 1;
346 		    while (*cp == ' ' || *cp == '\t')
347 			cp++;
348 		    cp[strcspn(cp, ";# \t\n")] = '\0';
349 		    if ((*cp != '\0') && (*cp != '\n')) {
350 			memset(&hints, 0, sizeof(hints));
351 			hints.ai_family = PF_UNSPEC;
352 			hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
353 			hints.ai_flags = AI_NUMERICHOST;
354 			sprintf(sbuf, "%u", NAMESERVER_PORT);
355 			if (getaddrinfo(cp, sbuf, &hints, &ai) == 0 &&
356 			    ai->ai_addrlen <= minsiz) {
357 			    if (statp->_u._ext.ext != NULL) {
358 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
359 				    ai->ai_addr, ai->ai_addrlen);
360 			    }
361 			    if (ai->ai_addrlen <=
362 			        sizeof(statp->nsaddr_list[nserv])) {
363 				memcpy(&statp->nsaddr_list[nserv],
364 				    ai->ai_addr, ai->ai_addrlen);
365 			    } else
366 				statp->nsaddr_list[nserv].sin_family = 0;
367 			    freeaddrinfo(ai);
368 			    nserv++;
369 			}
370 		    }
371 		    continue;
372 		}
373 		if (MATCH(buf, "sortlist")) {
374 		    struct in_addr a;
375 
376 		    cp = buf + sizeof("sortlist") - 1;
377 		    while (nsort < MAXRESOLVSORT) {
378 			while (*cp == ' ' || *cp == '\t')
379 			    cp++;
380 			if (*cp == '\0' || *cp == '\n' || *cp == ';')
381 			    break;
382 			net = cp;
383 			while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
384 			       isascii(*cp) && !isspace((unsigned char)*cp))
385 				cp++;
386 			n = *cp;
387 			*cp = 0;
388 			if (inet_aton(net, &a)) {
389 			    statp->sort_list[nsort].addr = a;
390 			    if (ISSORTMASK(n)) {
391 				*cp++ = n;
392 				net = cp;
393 				while (*cp && *cp != ';' &&
394 					isascii(*cp) &&
395 					!isspace((unsigned char)*cp))
396 				    cp++;
397 				n = *cp;
398 				*cp = 0;
399 				if (inet_aton(net, &a)) {
400 				    statp->sort_list[nsort].mask = a.s_addr;
401 				} else {
402 				    statp->sort_list[nsort].mask =
403 					net_mask(statp->sort_list[nsort].addr);
404 				}
405 			    } else {
406 				statp->sort_list[nsort].mask =
407 				    net_mask(statp->sort_list[nsort].addr);
408 			    }
409 			    nsort++;
410 			}
411 			*cp = n;
412 		    }
413 		    continue;
414 		}
415 		if (MATCH(buf, "options")) {
416 		    res_setoptions(statp, buf + sizeof("options") - 1, "conf");
417 		    continue;
418 		}
419 	    }
420 	    if (nserv > 0)
421 		statp->nscount = nserv;
422 	    statp->nsort = nsort;
423 	    (void) fclose(fp);
424 	}
425 /*
426  * Last chance to get a nameserver.  This should not normally
427  * be necessary
428  */
429 #ifdef NO_RESOLV_CONF
430 	if(nserv == 0)
431 		nserv = get_nameservers(statp);
432 #endif
433 
434 	if (statp->defdname[0] == 0 &&
435 	    gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
436 	    (cp = strchr(buf, '.')) != NULL)
437 		strcpy(statp->defdname, cp + 1);
438 
439 	/* find components of local domain that might be searched */
440 	if (havesearch == 0) {
441 		pp = statp->dnsrch;
442 		*pp++ = statp->defdname;
443 		*pp = NULL;
444 
445 		dots = 0;
446 		for (cp = statp->defdname; *cp; cp++)
447 			dots += (*cp == '.');
448 
449 		cp = statp->defdname;
450 		while (pp < statp->dnsrch + MAXDFLSRCH) {
451 			if (dots < LOCALDOMAINPARTS)
452 				break;
453 			cp = strchr(cp, '.') + 1;    /* we know there is one */
454 			*pp++ = cp;
455 			dots--;
456 		}
457 		*pp = NULL;
458 #ifdef DEBUG
459 		if (statp->options & RES_DEBUG) {
460 			printf(";; res_init()... default dnsrch list:\n");
461 			for (pp = statp->dnsrch; *pp; pp++)
462 				printf(";;\t%s\n", *pp);
463 			printf(";;\t..END..\n");
464 		}
465 #endif
466 	}
467 
468 	if ((cp = getenv("RES_OPTIONS")) != NULL)
469 		res_setoptions(statp, cp, "env");
470 	statp->options |= RES_INIT;
471 	return (0);
472 }
473 
474 static void
475 res_setoptions(res_state statp, const char *options, const char *source)
476 {
477 	const char *cp = options;
478 	int i;
479 	struct __res_state_ext *ext = statp->_u._ext.ext;
480 
481 #ifdef DEBUG
482 	if (statp->options & RES_DEBUG)
483 		printf(";; res_setoptions(\"%s\", \"%s\")...\n",
484 		       options, source);
485 #endif
486 	while (*cp) {
487 		/* skip leading and inner runs of spaces */
488 		while (*cp == ' ' || *cp == '\t')
489 			cp++;
490 		/* search for and process individual options */
491 		if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
492 			i = atoi(cp + sizeof("ndots:") - 1);
493 			if (i <= RES_MAXNDOTS)
494 				statp->ndots = i;
495 			else
496 				statp->ndots = RES_MAXNDOTS;
497 #ifdef DEBUG
498 			if (statp->options & RES_DEBUG)
499 				printf(";;\tndots=%d\n", statp->ndots);
500 #endif
501 		} else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
502 			i = atoi(cp + sizeof("timeout:") - 1);
503 			if (i <= RES_MAXRETRANS)
504 				statp->retrans = i;
505 			else
506 				statp->retrans = RES_MAXRETRANS;
507 #ifdef DEBUG
508 			if (statp->options & RES_DEBUG)
509 				printf(";;\ttimeout=%d\n", statp->retrans);
510 #endif
511 		} else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
512 			i = atoi(cp + sizeof("attempts:") - 1);
513 			if (i <= RES_MAXRETRY)
514 				statp->retry = i;
515 			else
516 				statp->retry = RES_MAXRETRY;
517 #ifdef DEBUG
518 			if (statp->options & RES_DEBUG)
519 				printf(";;\tattempts=%d\n", statp->retry);
520 #endif
521 		} else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
522 #ifdef DEBUG
523 			if (!(statp->options & RES_DEBUG)) {
524 				printf(";; res_setoptions(\"%s\", \"%s\")..\n",
525 				       options, source);
526 				statp->options |= RES_DEBUG;
527 			}
528 			printf(";;\tdebug\n");
529 #endif
530 		} else if (!strncmp(cp, "no_tld_query",
531 				    sizeof("no_tld_query") - 1) ||
532 			   !strncmp(cp, "no-tld-query",
533 				    sizeof("no-tld-query") - 1)) {
534 			statp->options |= RES_NOTLDQUERY;
535 		} else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
536 			statp->options |= RES_USE_INET6;
537 		} else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
538 			statp->options |= RES_ROTATE;
539 		} else if (!strncmp(cp, "no-check-names",
540 				    sizeof("no-check-names") - 1)) {
541 			statp->options |= RES_NOCHECKNAME;
542 		}
543 #ifdef RES_USE_EDNS0
544 		else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
545 			statp->options |= RES_USE_EDNS0;
546 		}
547 #endif
548 		else if (!strncmp(cp, "dname", sizeof("dname") - 1)) {
549 			statp->options |= RES_USE_DNAME;
550 		}
551 		else if (!strncmp(cp, "nibble:", sizeof("nibble:") - 1)) {
552 			if (ext == NULL)
553 				goto skip;
554 			cp += sizeof("nibble:") - 1;
555 			i = MIN(strcspn(cp, " \t"), sizeof(ext->nsuffix) - 1);
556 			strncpy(ext->nsuffix, cp, (size_t)i);
557 			ext->nsuffix[i] = '\0';
558 		}
559 		else if (!strncmp(cp, "nibble2:", sizeof("nibble2:") - 1)) {
560 			if (ext == NULL)
561 				goto skip;
562 			cp += sizeof("nibble2:") - 1;
563 			i = MIN(strcspn(cp, " \t"), sizeof(ext->nsuffix2) - 1);
564 			strncpy(ext->nsuffix2, cp, (size_t)i);
565 			ext->nsuffix2[i] = '\0';
566 		}
567 		else if (!strncmp(cp, "v6revmode:", sizeof("v6revmode:") - 1)) {
568 			cp += sizeof("v6revmode:") - 1;
569 			/* "nibble" and "bitstring" used to be valid */
570 			if (!strncmp(cp, "single", sizeof("single") - 1)) {
571 				statp->options |= RES_NO_NIBBLE2;
572 			} else if (!strncmp(cp, "both", sizeof("both") - 1)) {
573 				statp->options &=
574 					 ~RES_NO_NIBBLE2;
575 			}
576 		}
577 		else {
578 			/* XXX - print a warning here? */
579 		}
580    skip:
581 		/* skip to next run of spaces */
582 		while (*cp && *cp != ' ' && *cp != '\t')
583 			cp++;
584 	}
585 }
586 
587 /* XXX - should really support CIDR which means explicit masks always. */
588 static u_int32_t
589 net_mask(in)		/* XXX - should really use system's version of this */
590 	struct in_addr in;
591 {
592 	register u_int32_t i = ntohl(in.s_addr);
593 
594 	if (IN_CLASSA(i))
595 		return (htonl(IN_CLASSA_NET));
596 	else if (IN_CLASSB(i))
597 		return (htonl(IN_CLASSB_NET));
598 	return (htonl(IN_CLASSC_NET));
599 }
600 
601 u_int
602 res_randomid(void) {
603 	struct timeval now;
604 
605 	gettimeofday(&now, NULL);
606 	return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
607 }
608 
609 /*
610  * This routine is for closing the socket if a virtual circuit is used and
611  * the program wants to close it.  This provides support for endhostent()
612  * which expects to close the socket.
613  *
614  * This routine is not expected to be user visible.
615  */
616 void
617 res_nclose(res_state statp) {
618 	int ns;
619 
620 	if (statp->_vcsock >= 0) {
621 		(void) close(statp->_vcsock);
622 		statp->_vcsock = -1;
623 		statp->_flags &= ~(RES_F_VC | RES_F_CONN);
624 	}
625 	for (ns = 0; ns < statp->_u._ext.nscount; ns++) {
626 		if (statp->_u._ext.nssocks[ns] != -1) {
627 			(void) close(statp->_u._ext.nssocks[ns]);
628 			statp->_u._ext.nssocks[ns] = -1;
629 		}
630 	}
631 }
632 
633 void
634 res_ndestroy(res_state statp) {
635 	res_nclose(statp);
636 	if (statp->_u._ext.ext != NULL)
637 		free(statp->_u._ext.ext);
638 	statp->options &= ~RES_INIT;
639 	statp->_u._ext.ext = NULL;
640 }
641 
642 const char *
643 res_get_nibblesuffix(res_state statp) {
644 	if (statp->_u._ext.ext)
645 		return (statp->_u._ext.ext->nsuffix);
646 	return ("ip6.arpa");
647 }
648 
649 const char *
650 res_get_nibblesuffix2(res_state statp) {
651 	if (statp->_u._ext.ext)
652 		return (statp->_u._ext.ext->nsuffix2);
653 	return ("ip6.int");
654 }
655 
656 void
657 res_setservers(res_state statp, const union res_sockaddr_union *set, int cnt) {
658 	int i, nserv;
659 	size_t size;
660 
661 	/* close open servers */
662 	res_nclose(statp);
663 
664 	/* cause rtt times to be forgotten */
665 	statp->_u._ext.nscount = 0;
666 
667 	nserv = 0;
668 	for (i = 0; i < cnt && nserv < MAXNS; i++) {
669 		switch (set->sin.sin_family) {
670 		case AF_INET:
671 			size = sizeof(set->sin);
672 			if (statp->_u._ext.ext)
673 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
674 					&set->sin, size);
675 			if (size <= sizeof(statp->nsaddr_list[nserv]))
676 				memcpy(&statp->nsaddr_list[nserv],
677 					&set->sin, size);
678 #ifdef notdef
679 			else
680 				statp->nsaddr_list[nserv].sin_family = 0;
681 #endif
682 			nserv++;
683 			break;
684 
685 #ifdef HAS_INET6_STRUCTS
686 		case AF_INET6:
687 			size = sizeof(set->sin6);
688 			if (statp->_u._ext.ext)
689 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
690 					&set->sin6, size);
691 			if (size <= sizeof(statp->nsaddr_list[nserv]))
692 				memcpy(&statp->nsaddr_list[nserv],
693 					&set->sin6, size);
694 			else
695 				statp->nsaddr_list[nserv].sin_family = 0;
696 			nserv++;
697 			break;
698 #endif
699 
700 		default:
701 			break;
702 		}
703 		set++;
704 	}
705 	statp->nscount = nserv;
706 
707 }
708 
709 int
710 res_getservers(res_state statp, union res_sockaddr_union *set, int cnt) {
711 	int i;
712 	size_t size;
713 	u_int16_t family;
714 
715 	for (i = 0; i < statp->nscount && i < cnt; i++) {
716 		if (statp->_u._ext.ext)
717 			family = statp->_u._ext.ext->nsaddrs[i].sin.sin_family;
718 		else
719 			family = statp->nsaddr_list[i].sin_family;
720 
721 		switch (family) {
722 		case AF_INET:
723 			size = sizeof(set->sin);
724 			if (statp->_u._ext.ext)
725 				memcpy(&set->sin,
726 				       &statp->_u._ext.ext->nsaddrs[i],
727 				       size);
728 			else
729 				memcpy(&set->sin, &statp->nsaddr_list[i],
730 				       size);
731 			break;
732 
733 #ifdef HAS_INET6_STRUCTS
734 		case AF_INET6:
735 			size = sizeof(set->sin6);
736 			if (statp->_u._ext.ext)
737 				memcpy(&set->sin6,
738 				       &statp->_u._ext.ext->nsaddrs[i],
739 				       size);
740 			else
741 				memcpy(&set->sin6, &statp->nsaddr_list[i],
742 				       size);
743 			break;
744 #endif
745 
746 		default:
747 			set->sin.sin_family = 0;
748 			break;
749 		}
750 		set++;
751 	}
752 	return (statp->nscount);
753 }
754