xref: /illumos-gate/usr/src/lib/libresolv2/common/resolv/res_init.c (revision f9721e075222d67dfc8cab85ccca4a17f1eb8325)
1 /*
2  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 
6 /*
7  * Copyright (c) 1985, 1989, 1993
8  *    The Regents of the University of California.  All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  * 	This product includes software developed by the University of
21  * 	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 /*
40  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
41  *
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.
48  *
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
56  * SOFTWARE.
57  */
58 
59 /*
60  * Portions Copyright (c) 1996-1999 by Internet Software Consortium.
61  *
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.
65  *
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
73  * SOFTWARE.
74  */
75 
76 #pragma ident	"%Z%%M%	%I%	%E% SMI"
77 
78 #if defined(LIBC_SCCS) && !defined(lint)
79 static const char sccsid[] = "@(#)res_init.c	8.1 (Berkeley) 6/7/93";
80 static const char rcsid[] = "$Id: res_init.c,v 8.32 2003/04/03 06:31:10 marka Exp $";
81 #endif /* LIBC_SCCS and not lint */
82 
83 #include "port_before.h"
84 
85 #include <sys/types.h>
86 #include <sys/param.h>
87 #include <sys/socket.h>
88 #include <sys/time.h>
89 
90 #include <netinet/in.h>
91 #include <arpa/inet.h>
92 #include <arpa/nameser.h>
93 
94 #include <ctype.h>
95 #include <stdio.h>
96 #include <stdlib.h>
97 #include <string.h>
98 #include <unistd.h>
99 #include <netdb.h>
100 
101 #include "port_after.h"
102 #ifdef	SUNW_AVOIDSTDIO_FDLIMIT
103 #include "../../../libnsl/include/nsl_stdio_prv.h"
104 #endif
105 
106 /* ensure that sockaddr_in6 and IN6ADDR_ANY_INIT are declared / defined */
107 #include <resolv.h>
108 
109 #include "res_private.h"
110 
111 /* Options.  Should all be left alone. */
112 #define RESOLVSORT
113 #define DEBUG
114 
115 #ifdef  SUNW_INITCHKIF
116 #include <net/if.h>
117 #include <netinet/if_ether.h>
118 #include <sys/sockio.h>
119 #define MAXIFS  8192
120 #endif  /* SUNW_INITCHKIF */
121 
122 #ifdef  SUNW_DOMAINFROMNIS
123 #include <sys/systeminfo.h>
124 #include <string.h>
125 #endif  /* SUNW_DOMAINFROMNIS */
126 
127 #ifdef	ORIGINAL_ISC_CODE
128 #else
129 #pragma weak	__res_randomid	=	res_randomid
130 #endif	/* ORIGINAL_ISC_CODE */
131 
132 static void res_setoptions __P((res_state, const char *, const char *));
133 
134 #ifdef RESOLVSORT
135 static const char sort_mask[] = "/&";
136 #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL)
137 static u_int32_t net_mask __P((struct in_addr));
138 #endif
139 
140 #if !defined(isascii)	/* XXX - could be a function */
141 # define isascii(c) (!(c & 0200))
142 #endif
143 
144 /*
145  * Resolver state default settings.
146  */
147 
148 /*
149  * Set up default settings.  If the configuration file exist, the values
150  * there will have precedence.  Otherwise, the server address is set to
151  * INADDR_ANY and the default domain name comes from the gethostname().
152  *
153  * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1
154  * rather than INADDR_ANY ("0.0.0.0") as the default name server address
155  * since it was noted that INADDR_ANY actually meant ``the first interface
156  * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface,
157  * it had to be "up" in order for you to reach your own name server.  It
158  * was later decided that since the recommended practice is to always
159  * install local static routes through 127.0.0.1 for all your network
160  * interfaces, that we could solve this problem without a code change.
161  *
162  * The configuration file should always be used, since it is the only way
163  * to specify a default domain.  If you are running a server on your local
164  * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1"
165  * in the configuration file.
166  *
167  * Return 0 if completes successfully, -1 on error
168  */
169 int
170 res_ninit(res_state statp) {
171 	extern int __res_vinit(res_state, int);
172 
173 	return (__res_vinit(statp, 0));
174 }
175 
176 /* This function has to be reachable by res_data.c but not publically. */
177 int
178 __res_vinit(res_state statp, int preinit) {
179 #ifdef	SUNW_AVOIDSTDIO_FDLIMIT
180 	register __NSL_FILE *fp;
181 #else
182 	register FILE *fp;
183 #endif
184 	register char *cp, **pp;
185 	register int n;
186 	char buf[BUFSIZ];
187 	int nserv = 0;    /* number of nameserver records read from file */
188 	int haveenv = 0;
189 	int havesearch = 0;
190 #ifdef RESOLVSORT
191 	int nsort = 0;
192 	char *net;
193 #endif
194 	int dots;
195 	union res_sockaddr_union u[2];
196 
197 	if (!preinit) {
198 		statp->retrans = RES_TIMEOUT;
199 		statp->retry = RES_DFLRETRY;
200 		statp->options = RES_DEFAULT;
201 		statp->id = res_randomid();
202 	}
203 
204 	if ((statp->options & RES_INIT) != 0)
205 		res_ndestroy(statp);
206 
207 	memset(u, 0, sizeof(u));
208 #ifdef USELOOPBACK
209 	u[nserv].sin.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
210 #else
211 	u[nserv].sin.sin_addr.s_addr = INADDR_ANY;
212 #endif
213 	u[nserv].sin.sin_family = AF_INET;
214 	u[nserv].sin.sin_port = htons(NAMESERVER_PORT);
215 #ifdef HAVE_SA_LEN
216 	u[nserv].sin.sin_len = sizeof(struct sockaddr_in);
217 #endif
218 	nserv++;
219 #ifdef HAS_INET6_STRUCTS
220 #ifdef USELOOPBACK
221 	u[nserv].sin6.sin6_addr = in6addr_loopback;
222 #else
223 	u[nserv].sin6.sin6_addr = in6addr_any;
224 #endif
225 	u[nserv].sin6.sin6_family = AF_INET6;
226 	u[nserv].sin6.sin6_port = htons(NAMESERVER_PORT);
227 #ifdef HAVE_SA_LEN
228 	u[nserv].sin6.sin6_len = sizeof(struct sockaddr_in6);
229 #endif
230 	nserv++;
231 #endif
232 	statp->nscount = 0;
233 	statp->ndots = 1;
234 	statp->pfcode = 0;
235 	statp->_vcsock = -1;
236 	statp->_flags = 0;
237 	statp->qhook = NULL;
238 	statp->rhook = NULL;
239 	statp->_u._ext.nscount = 0;
240 	statp->_u._ext.ext = malloc(sizeof(*statp->_u._ext.ext));
241 	if (statp->_u._ext.ext != NULL) {
242 	        memset(statp->_u._ext.ext, 0, sizeof(*statp->_u._ext.ext));
243 		statp->_u._ext.ext->nsaddrs[0].sin = statp->nsaddr;
244 		strcpy(statp->_u._ext.ext->nsuffix, "ip6.arpa");
245 		strcpy(statp->_u._ext.ext->nsuffix2, "ip6.int");
246 	}
247 #ifdef RESOLVSORT
248 	statp->nsort = 0;
249 #endif
250 	res_setservers(statp, u, nserv);
251 
252 #ifdef  SUNW_INITCHKIF
253 /*
254  * Short circuit res_init() if no non-loopback interfaces are up. This is
255  * done to avoid boot delays if "dns" comes before "files" in nsswitch.conf.
256  * An additional fix has been added to this code, to count all external
257  * interfaces, which includes the IPv6 interfaces. If no external interfaces
258  * are found, an additional check is carried out to determine if any deprecated
259  * interfaces are up.
260  */
261 	{
262 		int s;
263 		struct lifnum lifn;
264 
265 		if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
266 			perror("res_init: socket");
267 			return (-1);
268 		}
269 		lifn.lifn_family = AF_UNSPEC;
270 		lifn.lifn_flags = LIFC_EXTERNAL_SOURCE;
271 		if (ioctl(s, SIOCGLIFNUM, (char *)&lifn) < 0) {
272 			close(s);
273 			return (-1);
274 		}
275 		if (lifn.lifn_count == 0) {
276 			/*
277 			 * Check if there are any deprecated interfaces up
278 			 */
279 			struct lifconf lifc;
280 			uchar_t *buf;
281 			int buflen, i, int_up = 0;
282 
283 			lifn.lifn_flags = 0;
284 			if ((ioctl(s, SIOCGLIFNUM, (char *)&lifn) < 0) ||
285 					(lifn.lifn_count < 1)) {
286 				close(s);
287 				return (-1);
288 			}
289 
290 			buflen = lifn.lifn_count * sizeof (struct lifreq);
291 			buf = (uchar_t *)malloc(buflen);
292 			if (buf == NULL) {
293 				close(s);
294 				return (-1);
295 			}
296 
297 			lifc.lifc_family = AF_UNSPEC;
298 			lifc.lifc_flags = 0;
299 			lifc.lifc_len = buflen;
300 			lifc.lifc_lifcu.lifcu_buf = (caddr_t)buf;
301 			if (ioctl(s, SIOCGLIFCONF, (char *)&lifc) < 0) {
302 				close(s);
303 				free(buf);
304 				return (-1);
305 			}
306 
307 			for (i = 0; i < lifn.lifn_count; ++i) {
308 				struct lifreq *lreqp, lreq;
309 
310 				lreqp = (struct lifreq *)&lifc.lifc_req[i];
311 				strlcpy(lreq.lifr_name, lreqp->lifr_name,
312 						sizeof (lreq.lifr_name));
313 				if (ioctl(s, SIOCGLIFFLAGS, &lreq) < 0) {
314 					close(s);
315 					free(buf);
316 					return (-1);
317 				}
318 				if ((lreq.lifr_flags & IFF_UP) &&
319 					!(lreq.lifr_flags & IFF_NOLOCAL) &&
320 					!(lreq.lifr_flags & IFF_NOXMIT) &&
321 					!(lreq.lifr_flags & IFF_LOOPBACK)) {
322 					int_up = 1;
323 					break;
324 				}
325 			}
326 			free(buf);
327 
328 			if (!int_up) {
329 				close(s);
330 				return (-1);
331 			}
332 		}
333 		close(s);
334 	}
335 #endif  /* SUNW_INITCHKIF */
336 
337 #ifdef  SUNW_DOMAINFROMNIS
338 /*
339  * The old (4.8.3) libresolv derived the default domainname from NIS/NIS+.
340  */
341         {
342                 char buf[sizeof(statp->defdname)], *cp;
343                 int  ret;
344                 if ((ret = sysinfo(SI_SRPC_DOMAIN, buf, sizeof(buf))) > 0 &&
345                     ret <= sizeof(buf)) {
346                         if (buf[0] == '+')
347                                 buf[0] = '.';
348                         cp = strchr(buf, '.');
349                         if (cp == 0)
350                                 strcpy(statp->defdname, buf);
351                         else
352                                 strcpy(statp->defdname, cp+1);
353                 }
354         }
355 #endif  /* SUNW_DOMAINFROMNIS */
356 
357 	/* Allow user to override the local domain definition */
358 	if ((cp = getenv("LOCALDOMAIN")) != NULL) {
359 		(void)strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
360 		statp->defdname[sizeof(statp->defdname) - 1] = '\0';
361 		haveenv++;
362 
363 		/*
364 		 * Set search list to be blank-separated strings
365 		 * from rest of env value.  Permits users of LOCALDOMAIN
366 		 * to still have a search list, and anyone to set the
367 		 * one that they want to use as an individual (even more
368 		 * important now that the rfc1535 stuff restricts searches)
369 		 */
370 		cp = statp->defdname;
371 		pp = statp->dnsrch;
372 		*pp++ = cp;
373 		for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
374 			if (*cp == '\n')	/* silly backwards compat */
375 				break;
376 			else if (*cp == ' ' || *cp == '\t') {
377 				*cp = 0;
378 				n = 1;
379 			} else if (n) {
380 				*pp++ = cp;
381 				n = 0;
382 				havesearch = 1;
383 			}
384 		}
385 		/* null terminate last domain if there are excess */
386 		while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
387 			cp++;
388 		*cp = '\0';
389 		*pp++ = 0;
390 	}
391 
392 #define	MATCH(line, name) \
393 	(!strncmp(line, name, sizeof(name) - 1) && \
394 	(line[sizeof(name) - 1] == ' ' || \
395 	 line[sizeof(name) - 1] == '\t'))
396 
397 	nserv = 0;
398 
399 #ifdef	SUNW_AVOIDSTDIO_FDLIMIT
400 	if ((fp = __nsl_fopen(_PATH_RESCONF, "r")) != NULL) {
401 	    /* read the config file */
402 	    while (__nsl_fgets(buf, sizeof(buf), fp) != NULL) {
403 #else
404 	if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) {
405 	    /* read the config file */
406 	    while (fgets(buf, sizeof(buf), fp) != NULL) {
407 #endif
408 		/* skip comments */
409 		if (*buf == ';' || *buf == '#')
410 			continue;
411 		/* read default domain name */
412 		if (MATCH(buf, "domain")) {
413 		    if (haveenv)	/* skip if have from environ */
414 			    continue;
415 		    cp = buf + sizeof("domain") - 1;
416 		    while (*cp == ' ' || *cp == '\t')
417 			    cp++;
418 		    if ((*cp == '\0') || (*cp == '\n'))
419 			    continue;
420 		    strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
421 		    statp->defdname[sizeof(statp->defdname) - 1] = '\0';
422 		    if ((cp = strpbrk(statp->defdname, " \t\n")) != NULL)
423 			    *cp = '\0';
424 		    havesearch = 0;
425 		    continue;
426 		}
427 		/* set search list */
428 		if (MATCH(buf, "search")) {
429 		    if (haveenv)	/* skip if have from environ */
430 			    continue;
431 		    cp = buf + sizeof("search") - 1;
432 		    while (*cp == ' ' || *cp == '\t')
433 			    cp++;
434 		    if ((*cp == '\0') || (*cp == '\n'))
435 			    continue;
436 		    strncpy(statp->defdname, cp, sizeof(statp->defdname) - 1);
437 		    statp->defdname[sizeof(statp->defdname) - 1] = '\0';
438 		    if ((cp = strchr(statp->defdname, '\n')) != NULL)
439 			    *cp = '\0';
440 		    /*
441 		     * Set search list to be blank-separated strings
442 		     * on rest of line.
443 		     */
444 		    cp = statp->defdname;
445 		    pp = statp->dnsrch;
446 		    *pp++ = cp;
447 		    for (n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++) {
448 			    if (*cp == ' ' || *cp == '\t') {
449 				    *cp = 0;
450 				    n = 1;
451 			    } else if (n) {
452 				    *pp++ = cp;
453 				    n = 0;
454 			    }
455 		    }
456 		    /* null terminate last domain if there are excess */
457 		    while (*cp != '\0' && *cp != ' ' && *cp != '\t')
458 			    cp++;
459 		    *cp = '\0';
460 		    *pp++ = 0;
461 		    havesearch = 1;
462 		    continue;
463 		}
464 		/* read nameservers to query */
465 		if (MATCH(buf, "nameserver") && nserv < MAXNS) {
466 		    struct addrinfo hints, *ai;
467 		    char sbuf[NI_MAXSERV];
468 		    const size_t minsiz =
469 		        sizeof(statp->_u._ext.ext->nsaddrs[0]);
470 
471 		    cp = buf + sizeof("nameserver") - 1;
472 		    while (*cp == ' ' || *cp == '\t')
473 			cp++;
474 		    cp[strcspn(cp, ";# \t\n")] = '\0';
475 		    if ((*cp != '\0') && (*cp != '\n')) {
476 			memset(&hints, 0, sizeof(hints));
477 			hints.ai_family = PF_UNSPEC;
478 			hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
479 			hints.ai_flags = AI_NUMERICHOST;
480 			sprintf(sbuf, "%u", NAMESERVER_PORT);
481 			if (getaddrinfo(cp, sbuf, &hints, &ai) == 0 &&
482 			    ai->ai_addrlen <= minsiz) {
483 			    if (statp->_u._ext.ext != NULL) {
484 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
485 				    ai->ai_addr, ai->ai_addrlen);
486 			    }
487 			    if (ai->ai_addrlen <=
488 			        sizeof(statp->nsaddr_list[nserv])) {
489 				memcpy(&statp->nsaddr_list[nserv],
490 				    ai->ai_addr, ai->ai_addrlen);
491 			    } else
492 				statp->nsaddr_list[nserv].sin_family = 0;
493 			    freeaddrinfo(ai);
494 			    nserv++;
495 			}
496 		    }
497 		    continue;
498 		}
499 #ifdef RESOLVSORT
500 		if (MATCH(buf, "sortlist")) {
501 		    struct in_addr a;
502 
503 		    cp = buf + sizeof("sortlist") - 1;
504 		    while (nsort < MAXRESOLVSORT) {
505 			while (*cp == ' ' || *cp == '\t')
506 			    cp++;
507 			if (*cp == '\0' || *cp == '\n' || *cp == ';')
508 			    break;
509 			net = cp;
510 			while (*cp && !ISSORTMASK(*cp) && *cp != ';' &&
511 			       isascii(*cp) && !isspace((unsigned char)*cp))
512 				cp++;
513 			n = *cp;
514 			*cp = 0;
515 			if (inet_aton(net, &a)) {
516 			    statp->sort_list[nsort].addr = a;
517 			    if (ISSORTMASK(n)) {
518 				*cp++ = n;
519 				net = cp;
520 				while (*cp && *cp != ';' &&
521 					isascii(*cp) &&
522 					!isspace((unsigned char)*cp))
523 				    cp++;
524 				n = *cp;
525 				*cp = 0;
526 				if (inet_aton(net, &a)) {
527 				    statp->sort_list[nsort].mask = a.s_addr;
528 				} else {
529 				    statp->sort_list[nsort].mask =
530 					net_mask(statp->sort_list[nsort].addr);
531 				}
532 			    } else {
533 				statp->sort_list[nsort].mask =
534 				    net_mask(statp->sort_list[nsort].addr);
535 			    }
536 			    nsort++;
537 			}
538 			*cp = n;
539 		    }
540 		    continue;
541 		}
542 #endif
543 		if (MATCH(buf, "options")) {
544 		    res_setoptions(statp, buf + sizeof("options") - 1, "conf");
545 		    continue;
546 		}
547 	    }
548 	    if (nserv > 0)
549 		statp->nscount = nserv;
550 #ifdef RESOLVSORT
551 	    statp->nsort = nsort;
552 #endif
553 
554 #ifdef	SUNW_AVOIDSTDIO_FDLIMIT
555 	    (void) __nsl_fclose(fp);
556 #else
557 		(void) fclose(fp);
558 #endif
559 	}
560 /*
561  * Last chance to get a nameserver.  This should not normally
562  * be necessary
563  */
564 #ifdef NO_RESOLV_CONF
565 	if(nserv == 0)
566 		nserv = get_nameservers(statp);
567 #endif
568 
569 	if (statp->defdname[0] == 0 &&
570 	    gethostname(buf, sizeof(statp->defdname) - 1) == 0 &&
571 	    (cp = strchr(buf, '.')) != NULL)
572 		strcpy(statp->defdname, cp + 1);
573 
574 	/* find components of local domain that might be searched */
575 	if (havesearch == 0) {
576 		pp = statp->dnsrch;
577 		*pp++ = statp->defdname;
578 		*pp = NULL;
579 
580 		dots = 0;
581 		for (cp = statp->defdname; *cp; cp++)
582 			dots += (*cp == '.');
583 
584 		cp = statp->defdname;
585 		while (pp < statp->dnsrch + MAXDFLSRCH) {
586 			if (dots < LOCALDOMAINPARTS)
587 				break;
588 			cp = strchr(cp, '.') + 1;    /* we know there is one */
589 			*pp++ = cp;
590 			dots--;
591 		}
592 		*pp = NULL;
593 #ifdef DEBUG
594 		if (statp->options & RES_DEBUG) {
595 			printf(";; res_init()... default dnsrch list:\n");
596 			for (pp = statp->dnsrch; *pp; pp++)
597 				printf(";;\t%s\n", *pp);
598 			printf(";;\t..END..\n");
599 		}
600 #endif
601 	}
602 
603 	if ((cp = getenv("RES_OPTIONS")) != NULL)
604 		res_setoptions(statp, cp, "env");
605 	statp->options |= RES_INIT;
606 	return (0);
607 }
608 
609 static void
610 res_setoptions(res_state statp, const char *options, const char *source)
611 {
612 	const char *cp = options;
613 	int i;
614 	struct __res_state_ext *ext = statp->_u._ext.ext;
615 
616 #ifdef DEBUG
617 	if (statp->options & RES_DEBUG)
618 		printf(";; res_setoptions(\"%s\", \"%s\")...\n",
619 		       options, source);
620 #endif
621 	while (*cp) {
622 		/* skip leading and inner runs of spaces */
623 		while (*cp == ' ' || *cp == '\t')
624 			cp++;
625 		/* search for and process individual options */
626 		if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) {
627 			i = atoi(cp + sizeof("ndots:") - 1);
628 			if (i <= RES_MAXNDOTS)
629 				statp->ndots = i;
630 			else
631 				statp->ndots = RES_MAXNDOTS;
632 #ifdef DEBUG
633 			if (statp->options & RES_DEBUG)
634 				printf(";;\tndots=%d\n", statp->ndots);
635 #endif
636 		} else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
637 			i = atoi(cp + sizeof("timeout:") - 1);
638 			if (i <= RES_MAXRETRANS)
639 				statp->retrans = i;
640 			else
641 				statp->retrans = RES_MAXRETRANS;
642 		} else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
643 			i = atoi(cp + sizeof("attempts:") - 1);
644 			if (i <= RES_MAXRETRY)
645 				statp->retry = i;
646 			else
647 				statp->retry = RES_MAXRETRY;
648 #ifdef	ORIGINAL_ISC_CODE
649 #else
650 		} else if (!strncmp(cp, "retrans:", sizeof("retrans:") - 1)) {
651 			/*
652 			 * For backward compatibility, 'retrans' is
653 			 * supported as an alias for 'timeout', though
654 			 * without an imposed maximum.
655 			 */
656 			statp->retrans = atoi(cp + sizeof("retrans:") - 1);
657 		} else if (!strncmp(cp, "retry:", sizeof("retry:") - 1)){
658 			/*
659 			 * For backward compatibility, 'retry' is
660 			 * supported as an alias for 'attempts', though
661 			 * without an imposed maximum.
662 			 */
663 			statp->retry = atoi(cp + sizeof("retry:") - 1);
664 #endif	/* ORIGINAL_ISC_CODE */
665 		} else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
666 #ifdef DEBUG
667 			if (!(statp->options & RES_DEBUG)) {
668 				printf(";; res_setoptions(\"%s\", \"%s\")..\n",
669 				       options, source);
670 				statp->options |= RES_DEBUG;
671 			}
672 			printf(";;\tdebug\n");
673 #endif
674 		} else if (!strncmp(cp, "no_tld_query",
675 				    sizeof("no_tld_query") - 1) ||
676 			   !strncmp(cp, "no-tld-query",
677 				    sizeof("no-tld-query") - 1)) {
678 			statp->options |= RES_NOTLDQUERY;
679 		} else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) {
680 			statp->options |= RES_USE_INET6;
681 		} else if (!strncmp(cp, "rotate", sizeof("rotate") - 1)) {
682 			statp->options |= RES_ROTATE;
683 		} else if (!strncmp(cp, "no-check-names",
684 				    sizeof("no-check-names") - 1)) {
685 			statp->options |= RES_NOCHECKNAME;
686 		}
687 #ifdef RES_USE_EDNS0
688 		else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
689 			statp->options |= RES_USE_EDNS0;
690 		}
691 #endif
692 		else if (!strncmp(cp, "dname", sizeof("dname") - 1)) {
693 			statp->options |= RES_USE_DNAME;
694 		}
695 		else if (!strncmp(cp, "nibble:", sizeof("nibble:") - 1)) {
696 			if (ext == NULL)
697 				goto skip;
698 			cp += sizeof("nibble:") - 1;
699 			i = MIN(strcspn(cp, " \t"), sizeof(ext->nsuffix) - 1);
700 			strncpy(ext->nsuffix, cp, i);
701 			ext->nsuffix[i] = '\0';
702 		}
703 		else if (!strncmp(cp, "nibble2:", sizeof("nibble2:") - 1)) {
704 			if (ext == NULL)
705 				goto skip;
706 			cp += sizeof("nibble2:") - 1;
707 			i = MIN(strcspn(cp, " \t"), sizeof(ext->nsuffix2) - 1);
708 			strncpy(ext->nsuffix2, cp, i);
709 			ext->nsuffix2[i] = '\0';
710 		}
711 		else if (!strncmp(cp, "v6revmode:", sizeof("v6revmode:") - 1)) {
712 			cp += sizeof("v6revmode:") - 1;
713 			/* "nibble" and "bitstring" used to be valid */
714 			if (!strncmp(cp, "single", sizeof("single") - 1)) {
715 				statp->options |= RES_NO_NIBBLE2;
716 			} else if (!strncmp(cp, "both", sizeof("both") - 1)) {
717 				statp->options &=
718 					 ~RES_NO_NIBBLE2;
719 			}
720 		}
721 		else {
722 			/* XXX - print a warning here? */
723 		}
724    skip:
725 		/* skip to next run of spaces */
726 		while (*cp && *cp != ' ' && *cp != '\t')
727 			cp++;
728 	}
729 }
730 
731 #ifdef RESOLVSORT
732 /* XXX - should really support CIDR which means explicit masks always. */
733 static u_int32_t
734 net_mask(in)		/* XXX - should really use system's version of this */
735 	struct in_addr in;
736 {
737 	register u_int32_t i = ntohl(in.s_addr);
738 
739 	if (IN_CLASSA(i))
740 		return (htonl(IN_CLASSA_NET));
741 	else if (IN_CLASSB(i))
742 		return (htonl(IN_CLASSB_NET));
743 	return (htonl(IN_CLASSC_NET));
744 }
745 #endif
746 
747 u_int
748 res_randomid(void) {
749 	struct timeval now;
750 
751 	gettimeofday(&now, NULL);
752 	return (0xffff & (now.tv_sec ^ now.tv_usec ^ getpid()));
753 }
754 
755 /*
756  * This routine is for closing the socket if a virtual circuit is used and
757  * the program wants to close it.  This provides support for endhostent()
758  * which expects to close the socket.
759  *
760  * This routine is not expected to be user visible.
761  */
762 void
763 res_nclose(res_state statp) {
764 	int ns;
765 
766 	if (statp->_vcsock >= 0) {
767 		(void) close(statp->_vcsock);
768 		statp->_vcsock = -1;
769 		statp->_flags &= ~(RES_F_VC | RES_F_CONN);
770 	}
771 	for (ns = 0; ns < statp->_u._ext.nscount; ns++) {
772 		if (statp->_u._ext.nssocks[ns] != -1) {
773 			(void) close(statp->_u._ext.nssocks[ns]);
774 			statp->_u._ext.nssocks[ns] = -1;
775 		}
776 	}
777 }
778 
779 void
780 res_ndestroy(res_state statp) {
781 	res_nclose(statp);
782 	if (statp->_u._ext.ext != NULL)
783 		free(statp->_u._ext.ext);
784 	statp->options &= ~RES_INIT;
785 	statp->_u._ext.ext = NULL;
786 }
787 
788 const char *
789 res_get_nibblesuffix(res_state statp) {
790 	if (statp->_u._ext.ext)
791 		return (statp->_u._ext.ext->nsuffix);
792 	return ("ip6.arpa");
793 }
794 
795 const char *
796 res_get_nibblesuffix2(res_state statp) {
797 	if (statp->_u._ext.ext)
798 		return (statp->_u._ext.ext->nsuffix2);
799 	return ("ip6.int");
800 }
801 
802 void
803 res_setservers(res_state statp, const union res_sockaddr_union *set, int cnt) {
804 	int i, nserv;
805 	size_t size;
806 
807 	/* close open servers */
808 	res_nclose(statp);
809 
810 	/* cause rtt times to be forgotten */
811 	statp->_u._ext.nscount = 0;
812 
813 	nserv = 0;
814 	for (i = 0; i < cnt && nserv < MAXNS; i++) {
815 		switch (set->sin.sin_family) {
816 		case AF_INET:
817 			size = sizeof(set->sin);
818 			if (statp->_u._ext.ext)
819 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
820 					&set->sin, size);
821 			if (size <= sizeof(statp->nsaddr_list[nserv]))
822 				memcpy(&statp->nsaddr_list[nserv],
823 					&set->sin, size);
824 			else
825 				statp->nsaddr_list[nserv].sin_family = 0;
826 			nserv++;
827 			break;
828 
829 #ifdef HAS_INET6_STRUCTS
830 		case AF_INET6:
831 			size = sizeof(set->sin6);
832 			if (statp->_u._ext.ext)
833 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
834 					&set->sin6, size);
835 			if (size <= sizeof(statp->nsaddr_list[nserv]))
836 				memcpy(&statp->nsaddr_list[nserv],
837 					&set->sin6, size);
838 			else
839 				statp->nsaddr_list[nserv].sin_family = 0;
840 			nserv++;
841 			break;
842 #endif
843 
844 		default:
845 			break;
846 		}
847 		set++;
848 	}
849 	statp->nscount = nserv;
850 
851 }
852 
853 int
854 res_getservers(res_state statp, union res_sockaddr_union *set, int cnt) {
855 	int i;
856 	size_t size;
857 	u_int16_t family;
858 
859 	for (i = 0; i < statp->nscount && i < cnt; i++) {
860 		if (statp->_u._ext.ext)
861 			family = statp->_u._ext.ext->nsaddrs[i].sin.sin_family;
862 		else
863 			family = statp->nsaddr_list[i].sin_family;
864 
865 		switch (family) {
866 		case AF_INET:
867 			size = sizeof(set->sin);
868 			if (statp->_u._ext.ext)
869 				memcpy(&set->sin,
870 				       &statp->_u._ext.ext->nsaddrs[i],
871 				       size);
872 			else
873 				memcpy(&set->sin, &statp->nsaddr_list[i],
874 				       size);
875 			break;
876 
877 #ifdef HAS_INET6_STRUCTS
878 		case AF_INET6:
879 			size = sizeof(set->sin6);
880 			if (statp->_u._ext.ext)
881 				memcpy(&set->sin6,
882 				       &statp->_u._ext.ext->nsaddrs[i],
883 				       size);
884 			else
885 				memcpy(&set->sin6, &statp->nsaddr_list[i],
886 				       size);
887 			break;
888 #endif
889 
890 		default:
891 			set->sin.sin_family = 0;
892 			break;
893 		}
894 		set++;
895 	}
896 	return (statp->nscount);
897 }
898