xref: /netbsd-src/lib/libc/resolv/res_init.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06)
1 /*	$NetBSD: res_init.c,v 1.6 2005/09/15 23:33:41 tsarna 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 1.6 2005/09/15 23:33:41 tsarna 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 #define DEBUG
125 
126 static void res_setoptions __P((res_state, const char *, const char *));
127 
128 static const char sort_mask[] = "/&";
129 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
130 static u_int32_t net_mask __P((struct in_addr));
131 
132 #if !defined(isascii)	/* XXX - could be a function */
133 # define isascii(c) (!(c & 0200))
134 #endif
135 
136 /*
137  * Resolver state default settings.
138  */
139 
140 /*
141  * Set up default settings.  If the configuration file exist, the values
142  * there will have precedence.  Otherwise, the server address is set to
143  * INADDR_ANY and the default domain name comes from the gethostname().
144  *
145  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
146  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
147  * since it was noted that INADDR_ANY actually meant ``the first interface
148  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
149  * it had to be "up" in order for you to reach your own name server.  It
150  * was later decided that since the recommended practice is to always
151  * install local static routes through 127.0.0.1 for all your network
152  * interfaces, that we could solve this problem without a code change.
153  *
154  * The configuration file should always be used, since it is the only way
155  * to specify a default domain.  If you are running a server on your local
156  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
157  * in the configuration file.
158  *
159  * Return 0 if completes successfully, -1 on error
160  */
161 int
162 res_ninit(res_state statp) {
163 	extern int __res_vinit(res_state, int);
164 
165 	return (__res_vinit(statp, 0));
166 }
167 
168 /* This function has to be reachable by res_data.c but not publically. */
169 int
170 __res_vinit(res_state statp, int preinit) {
171 	register FILE *fp;
172 	register char *cp, **pp;
173 	register int n;
174 	char buf[BUFSIZ];
175 	int nserv = 0;    /* number of nameserver records read from file */
176 	int haveenv = 0;
177 	int havesearch = 0;
178 	int nsort = 0;
179 	char *net;
180 	int dots;
181 	union res_sockaddr_union u[2];
182 
183 	if (!preinit) {
184 		statp->retrans = RES_TIMEOUT;
185 		statp->retry = RES_DFLRETRY;
186 		statp->options = RES_DEFAULT;
187 		statp->id = res_randomid();
188 	}
189 
190 	if ((statp->options & RES_INIT) != 0U)
191 		res_ndestroy(statp);
192 
193 	memset(u, 0, sizeof(u));
194 #ifdef USELOOPBACK
195 	u[nserv].sin.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
196 #else
197 	u[nserv].sin.sin_addr.s_addr = INADDR_ANY;
198 #endif
199 	u[nserv].sin.sin_family = AF_INET;
200 	u[nserv].sin.sin_port = htons(NAMESERVER_PORT);
201 #ifdef HAVE_SA_LEN
202 	u[nserv].sin.sin_len = sizeof(struct sockaddr_in);
203 #endif
204 	nserv++;
205 #ifdef HAS_INET6_STRUCTS
206 #ifdef USELOOPBACK
207 	u[nserv].sin6.sin6_addr = in6addr_loopback;
208 #else
209 	u[nserv].sin6.sin6_addr = in6addr_any;
210 #endif
211 	u[nserv].sin6.sin6_family = AF_INET6;
212 	u[nserv].sin6.sin6_port = htons(NAMESERVER_PORT);
213 #ifdef HAVE_SA_LEN
214 	u[nserv].sin6.sin6_len = sizeof(struct sockaddr_in6);
215 #endif
216 	nserv++;
217 #endif
218 	statp->nscount = 0;
219 	statp->ndots = 1;
220 	statp->pfcode = 0;
221 	statp->_vcsock = -1;
222 	statp->_flags = 0;
223 	statp->qhook = NULL;
224 	statp->rhook = NULL;
225 	statp->_u._ext.nscount = 0;
226 	statp->_u._ext.ext = malloc(sizeof(*statp->_u._ext.ext));
227 	if (statp->_u._ext.ext != NULL) {
228 	        memset(statp->_u._ext.ext, 0, sizeof(*statp->_u._ext.ext));
229 		statp->_u._ext.ext->nsaddrs[0].sin = statp->nsaddr;
230 		strcpy(statp->_u._ext.ext->nsuffix, "ip6.arpa");
231 		strcpy(statp->_u._ext.ext->nsuffix2, "ip6.int");
232 	}
233 	statp->nsort = 0;
234 	res_setservers(statp, u, nserv);
235 
236 	/* Allow user to override the local domain definition */
237 	if ((cp = getenv("LOCALDOMAIN")) != NULL) {
238 		(void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
239 		statp->defdname[sizeof(statp->defdname) - 1] = '\0';
240 		haveenv++;
241 
242 		/*
243 		 * Set search list to be blank-separated strings
244 		 * from rest of env value.  Permits users of LOCALDOMAIN
245 		 * to still have a search list, and anyone to set the
246 		 * one that they want to use as an individual (even more
247 		 * important now that the rfc1535 stuff restricts searches)
248 		 */
249 		cp = statp->defdname;
250 		pp = statp->dnsrch;
251 		*pp++ = cp;
252 		for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
253 			if (*cp == '\n')	/* silly backwards compat */
254 				break;
255 			else if (*cp == ' ' || *cp == '\t') {
256 				*cp = 0;
257 				n = 1;
258 			} else if (n) {
259 				*pp++ = cp;
260 				n = 0;
261 				havesearch = 1;
262 			}
263 		}
264 		/* null terminate last domain if there are excess */
265 		while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
266 			cp++;
267 		*cp = '\0';
268 		*pp++ = 0;
269 	}
270 
271 #define	MATCH(line, name) \
272 	(!strncmp(line, name, sizeof(name) - 1) && \
273 	(line[sizeof(name) - 1] == ' ' || \
274 	 line[sizeof(name) - 1] == '\t'))
275 
276 	nserv = 0;
277 	if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
278 	    /* read the config file */
279 	    while (fgets(buf, sizeof(buf), fp) != NULL) {
280 		/* skip comments */
281 		if (*buf == ';' || *buf == '#')
282 			continue;
283 		/* read default domain name */
284 		if (MATCH(buf, "domain")) {
285 		    if (haveenv)	/* skip if have from environ */
286 			    continue;
287 		    cp = buf + sizeof("domain") - 1;
288 		    while (*cp == ' ' || *cp == '\t')
289 			    cp++;
290 		    if ((*cp == '\0') || (*cp == '\n'))
291 			    continue;
292 		    strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
293 		    statp->defdname[sizeof(statp->defdname) - 1] = '\0';
294 		    if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
295 			    *cp = '\0';
296 		    havesearch = 0;
297 		    continue;
298 		}
299 		/* set search list */
300 		if (MATCH(buf, "search")) {
301 		    if (haveenv)	/* skip if have from environ */
302 			    continue;
303 		    cp = buf + sizeof("search") - 1;
304 		    while (*cp == ' ' || *cp == '\t')
305 			    cp++;
306 		    if ((*cp == '\0') || (*cp == '\n'))
307 			    continue;
308 		    strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
309 		    statp->defdname[sizeof(statp->defdname) - 1] = '\0';
310 		    if ((cp = strchr(statp->defdname, '\n')) != NULL)
311 			    *cp = '\0';
312 		    /*
313 		     * Set search list to be blank-separated strings
314 		     * on rest of line.
315 		     */
316 		    cp = statp->defdname;
317 		    pp = statp->dnsrch;
318 		    *pp++ = cp;
319 		    for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
320 			    if (*cp == ' ' || *cp == '\t') {
321 				    *cp = 0;
322 				    n = 1;
323 			    } else if (n) {
324 				    *pp++ = cp;
325 				    n = 0;
326 			    }
327 		    }
328 		    /* null terminate last domain if there are excess */
329 		    while (*cp != '\0' && *cp != ' ' && *cp != '\t')
330 			    cp++;
331 		    *cp = '\0';
332 		    *pp++ = 0;
333 		    havesearch = 1;
334 		    continue;
335 		}
336 		/* read nameservers to query */
337 		if (MATCH(buf, "nameserver") && nserv < MAXNS) {
338 		    struct addrinfo hints, *ai;
339 		    char sbuf[NI_MAXSERV];
340 		    const size_t minsiz =
341 		        sizeof(statp->_u._ext.ext->nsaddrs[0]);
342 
343 		    cp = buf + sizeof("nameserver") - 1;
344 		    while (*cp == ' ' || *cp == '\t')
345 			cp++;
346 		    cp[strcspn(cp, ";# \t\n")] = '\0';
347 		    if ((*cp != '\0') && (*cp != '\n')) {
348 			memset(&hints, 0, sizeof(hints));
349 			hints.ai_family = PF_UNSPEC;
350 			hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
351 			hints.ai_flags = AI_NUMERICHOST;
352 			sprintf(sbuf, "%u", NAMESERVER_PORT);
353 			if (getaddrinfo(cp, sbuf, &hints, &ai) == 0 &&
354 			    ai->ai_addrlen <= minsiz) {
355 			    if (statp->_u._ext.ext != NULL) {
356 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
357 				    ai->ai_addr, ai->ai_addrlen);
358 			    }
359 			    if (ai->ai_addrlen <=
360 			        sizeof(statp->nsaddr_list[nserv])) {
361 				memcpy(&statp->nsaddr_list[nserv],
362 				    ai->ai_addr, ai->ai_addrlen);
363 			    } else
364 				statp->nsaddr_list[nserv].sin_family = 0;
365 			    freeaddrinfo(ai);
366 			    nserv++;
367 			}
368 		    }
369 		    continue;
370 		}
371 		if (MATCH(buf, "sortlist")) {
372 		    struct in_addr a;
373 
374 		    cp = buf + sizeof("sortlist") - 1;
375 		    while (nsort < MAXRESOLVSORT) {
376 			while (*cp == ' ' || *cp == '\t')
377 			    cp++;
378 			if (*cp == '\0' || *cp == '\n' || *cp == ';')
379 			    break;
380 			net = cp;
381 			while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
382 			       isascii(*cp) && !isspace((unsigned char)*cp))
383 				cp++;
384 			n = *cp;
385 			*cp = 0;
386 			if (inet_aton(net, &a)) {
387 			    statp->sort_list[nsort].addr = a;
388 			    if (ISSORTMASK(n)) {
389 				*cp++ = n;
390 				net = cp;
391 				while (*cp && *cp != ';' &&
392 					isascii(*cp) &&
393 					!isspace((unsigned char)*cp))
394 				    cp++;
395 				n = *cp;
396 				*cp = 0;
397 				if (inet_aton(net, &a)) {
398 				    statp->sort_list[nsort].mask = a.s_addr;
399 				} else {
400 				    statp->sort_list[nsort].mask =
401 					net_mask(statp->sort_list[nsort].addr);
402 				}
403 			    } else {
404 				statp->sort_list[nsort].mask =
405 				    net_mask(statp->sort_list[nsort].addr);
406 			    }
407 			    nsort++;
408 			}
409 			*cp = n;
410 		    }
411 		    continue;
412 		}
413 		if (MATCH(buf, "options")) {
414 		    res_setoptions(statp, buf + sizeof("options") - 1, "conf");
415 		    continue;
416 		}
417 	    }
418 	    if (nserv > 0)
419 		statp->nscount = nserv;
420 	    statp->nsort = nsort;
421 	    (void) fclose(fp);
422 	}
423 /*
424  * Last chance to get a nameserver.  This should not normally
425  * be necessary
426  */
427 #ifdef NO_RESOLV_CONF
428 	if(nserv == 0)
429 		nserv = get_nameservers(statp);
430 #endif
431 
432 	if (statp->defdname[0] == 0 &&
433 	    gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
434 	    (cp = strchr(buf, '.')) != NULL)
435 		strcpy(statp->defdname, cp + 1);
436 
437 	/* find components of local domain that might be searched */
438 	if (havesearch == 0) {
439 		pp = statp->dnsrch;
440 		*pp++ = statp->defdname;
441 		*pp = NULL;
442 
443 		dots = 0;
444 		for (cp = statp->defdname; *cp; cp++)
445 			dots += (*cp == '.');
446 
447 		cp = statp->defdname;
448 		while (pp < statp->dnsrch + MAXDFLSRCH) {
449 			if (dots < LOCALDOMAINPARTS)
450 				break;
451 			cp = strchr(cp, '.') + 1;    /* we know there is one */
452 			*pp++ = cp;
453 			dots--;
454 		}
455 		*pp = NULL;
456 #ifdef DEBUG
457 		if (statp->options & RES_DEBUG) {
458 			printf(";; res_init()... default dnsrch list:\n");
459 			for (pp = statp->dnsrch; *pp; pp++)
460 				printf(";;\t%s\n", *pp);
461 			printf(";;\t..END..\n");
462 		}
463 #endif
464 	}
465 
466 	if ((cp = getenv("RES_OPTIONS")) != NULL)
467 		res_setoptions(statp, cp, "env");
468 	statp->options |= RES_INIT;
469 	return (0);
470 }
471 
472 static void
473 res_setoptions(res_state statp, const char *options, const char *source)
474 {
475 	const char *cp = options;
476 	int i;
477 	struct __res_state_ext *ext = statp->_u._ext.ext;
478 
479 #ifdef DEBUG
480 	if (statp->options & RES_DEBUG)
481 		printf(";; res_setoptions(\"%s\", \"%s\")...\n",
482 		       options, source);
483 #endif
484 	while (*cp) {
485 		/* skip leading and inner runs of spaces */
486 		while (*cp == ' ' || *cp == '\t')
487 			cp++;
488 		/* search for and process individual options */
489 		if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
490 			i = atoi(cp + sizeof("ndots:") - 1);
491 			if (i <= RES_MAXNDOTS)
492 				statp->ndots = i;
493 			else
494 				statp->ndots = RES_MAXNDOTS;
495 #ifdef DEBUG
496 			if (statp->options & RES_DEBUG)
497 				printf(";;\tndots=%d\n", statp->ndots);
498 #endif
499 		} else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
500 			i = atoi(cp + sizeof("timeout:") - 1);
501 			if (i <= RES_MAXRETRANS)
502 				statp->retrans = i;
503 			else
504 				statp->retrans = RES_MAXRETRANS;
505 #ifdef DEBUG
506 			if (statp->options & RES_DEBUG)
507 				printf(";;\ttimeout=%d\n", statp->retrans);
508 #endif
509 		} else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
510 			i = atoi(cp + sizeof("attempts:") - 1);
511 			if (i <= RES_MAXRETRY)
512 				statp->retry = i;
513 			else
514 				statp->retry = RES_MAXRETRY;
515 #ifdef DEBUG
516 			if (statp->options & RES_DEBUG)
517 				printf(";;\tattempts=%d\n", statp->retry);
518 #endif
519 		} else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
520 #ifdef DEBUG
521 			if (!(statp->options & RES_DEBUG)) {
522 				printf(";; res_setoptions(\"%s\", \"%s\")..\n",
523 				       options, source);
524 				statp->options |= RES_DEBUG;
525 			}
526 			printf(";;\tdebug\n");
527 #endif
528 		} else if (!strncmp(cp, "no_tld_query",
529 				    sizeof("no_tld_query") - 1) ||
530 			   !strncmp(cp, "no-tld-query",
531 				    sizeof("no-tld-query") - 1)) {
532 			statp->options |= RES_NOTLDQUERY;
533 		} else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
534 			statp->options |= RES_USE_INET6;
535 		} else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
536 			statp->options |= RES_ROTATE;
537 		} else if (!strncmp(cp, "no-check-names",
538 				    sizeof("no-check-names") - 1)) {
539 			statp->options |= RES_NOCHECKNAME;
540 		}
541 #ifdef RES_USE_EDNS0
542 		else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
543 			statp->options |= RES_USE_EDNS0;
544 		}
545 #endif
546 		else if (!strncmp(cp, "dname", sizeof("dname") - 1)) {
547 			statp->options |= RES_USE_DNAME;
548 		}
549 		else if (!strncmp(cp, "nibble:", sizeof("nibble:") - 1)) {
550 			if (ext == NULL)
551 				goto skip;
552 			cp += sizeof("nibble:") - 1;
553 			i = MIN(strcspn(cp, " \t"), sizeof(ext->nsuffix) - 1);
554 			strncpy(ext->nsuffix, cp, (size_t)i);
555 			ext->nsuffix[i] = '\0';
556 		}
557 		else if (!strncmp(cp, "nibble2:", sizeof("nibble2:") - 1)) {
558 			if (ext == NULL)
559 				goto skip;
560 			cp += sizeof("nibble2:") - 1;
561 			i = MIN(strcspn(cp, " \t"), sizeof(ext->nsuffix2) - 1);
562 			strncpy(ext->nsuffix2, cp, (size_t)i);
563 			ext->nsuffix2[i] = '\0';
564 		}
565 		else if (!strncmp(cp, "v6revmode:", sizeof("v6revmode:") - 1)) {
566 			cp += sizeof("v6revmode:") - 1;
567 			/* "nibble" and "bitstring" used to be valid */
568 			if (!strncmp(cp, "single", sizeof("single") - 1)) {
569 				statp->options |= RES_NO_NIBBLE2;
570 			} else if (!strncmp(cp, "both", sizeof("both") - 1)) {
571 				statp->options &=
572 					 ~RES_NO_NIBBLE2;
573 			}
574 		}
575 		else {
576 			/* XXX - print a warning here? */
577 		}
578    skip:
579 		/* skip to next run of spaces */
580 		while (*cp && *cp != ' ' && *cp != '\t')
581 			cp++;
582 	}
583 }
584 
585 /* XXX - should really support CIDR which means explicit masks always. */
586 static u_int32_t
587 net_mask(in)		/* XXX - should really use system's version of this */
588 	struct in_addr in;
589 {
590 	register u_int32_t i = ntohl(in.s_addr);
591 
592 	if (IN_CLASSA(i))
593 		return (htonl(IN_CLASSA_NET));
594 	else if (IN_CLASSB(i))
595 		return (htonl(IN_CLASSB_NET));
596 	return (htonl(IN_CLASSC_NET));
597 }
598 
599 u_int
600 res_randomid(void) {
601 	struct timeval now;
602 
603 	gettimeofday(&now, NULL);
604 	return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
605 }
606 
607 /*
608  * This routine is for closing the socket if a virtual circuit is used and
609  * the program wants to close it.  This provides support for endhostent()
610  * which expects to close the socket.
611  *
612  * This routine is not expected to be user visible.
613  */
614 void
615 res_nclose(res_state statp) {
616 	int ns;
617 
618 	if (statp->_vcsock >= 0) {
619 		(void) close(statp->_vcsock);
620 		statp->_vcsock = -1;
621 		statp->_flags &= ~(RES_F_VC | RES_F_CONN);
622 	}
623 	for (ns = 0; ns < statp->_u._ext.nscount; ns++) {
624 		if (statp->_u._ext.nssocks[ns] != -1) {
625 			(void) close(statp->_u._ext.nssocks[ns]);
626 			statp->_u._ext.nssocks[ns] = -1;
627 		}
628 	}
629 }
630 
631 void
632 res_ndestroy(res_state statp) {
633 	res_nclose(statp);
634 	if (statp->_u._ext.ext != NULL)
635 		free(statp->_u._ext.ext);
636 	statp->options &= ~RES_INIT;
637 	statp->_u._ext.ext = NULL;
638 }
639 
640 const char *
641 res_get_nibblesuffix(res_state statp) {
642 	if (statp->_u._ext.ext)
643 		return (statp->_u._ext.ext->nsuffix);
644 	return ("ip6.arpa");
645 }
646 
647 const char *
648 res_get_nibblesuffix2(res_state statp) {
649 	if (statp->_u._ext.ext)
650 		return (statp->_u._ext.ext->nsuffix2);
651 	return ("ip6.int");
652 }
653 
654 void
655 res_setservers(res_state statp, const union res_sockaddr_union *set, int cnt) {
656 	int i, nserv;
657 	size_t size;
658 
659 	/* close open servers */
660 	res_nclose(statp);
661 
662 	/* cause rtt times to be forgotten */
663 	statp->_u._ext.nscount = 0;
664 
665 	nserv = 0;
666 	for (i = 0; i < cnt && nserv < MAXNS; i++) {
667 		switch (set->sin.sin_family) {
668 		case AF_INET:
669 			size = sizeof(set->sin);
670 			if (statp->_u._ext.ext)
671 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
672 					&set->sin, size);
673 			if (size <= sizeof(statp->nsaddr_list[nserv]))
674 				memcpy(&statp->nsaddr_list[nserv],
675 					&set->sin, size);
676 			else
677 				statp->nsaddr_list[nserv].sin_family = 0;
678 			nserv++;
679 			break;
680 
681 #ifdef HAS_INET6_STRUCTS
682 		case AF_INET6:
683 			size = sizeof(set->sin6);
684 			if (statp->_u._ext.ext)
685 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
686 					&set->sin6, size);
687 			if (size <= sizeof(statp->nsaddr_list[nserv]))
688 				memcpy(&statp->nsaddr_list[nserv],
689 					&set->sin6, size);
690 			else
691 				statp->nsaddr_list[nserv].sin_family = 0;
692 			nserv++;
693 			break;
694 #endif
695 
696 		default:
697 			break;
698 		}
699 		set++;
700 	}
701 	statp->nscount = nserv;
702 
703 }
704 
705 int
706 res_getservers(res_state statp, union res_sockaddr_union *set, int cnt) {
707 	int i;
708 	size_t size;
709 	u_int16_t family;
710 
711 	for (i = 0; i < statp->nscount && i < cnt; i++) {
712 		if (statp->_u._ext.ext)
713 			family = statp->_u._ext.ext->nsaddrs[i].sin.sin_family;
714 		else
715 			family = statp->nsaddr_list[i].sin_family;
716 
717 		switch (family) {
718 		case AF_INET:
719 			size = sizeof(set->sin);
720 			if (statp->_u._ext.ext)
721 				memcpy(&set->sin,
722 				       &statp->_u._ext.ext->nsaddrs[i],
723 				       size);
724 			else
725 				memcpy(&set->sin, &statp->nsaddr_list[i],
726 				       size);
727 			break;
728 
729 #ifdef HAS_INET6_STRUCTS
730 		case AF_INET6:
731 			size = sizeof(set->sin6);
732 			if (statp->_u._ext.ext)
733 				memcpy(&set->sin6,
734 				       &statp->_u._ext.ext->nsaddrs[i],
735 				       size);
736 			else
737 				memcpy(&set->sin6, &statp->nsaddr_list[i],
738 				       size);
739 			break;
740 #endif
741 
742 		default:
743 			set->sin.sin_family = 0;
744 			break;
745 		}
746 		set++;
747 	}
748 	return (statp->nscount);
749 }
750