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res_init.c revision 1.7
      1 /*	$NetBSD: res_init.c,v 1.7 2006/01/24 17:39:44 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 1.7 2006/01/24 17:39:44 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 			else
    679 				statp->nsaddr_list[nserv].sin_family = 0;
    680 			nserv++;
    681 			break;
    682 
    683 #ifdef HAS_INET6_STRUCTS
    684 		case AF_INET6:
    685 			size = sizeof(set->sin6);
    686 			if (statp->_u._ext.ext)
    687 				memcpy(&statp->_u._ext.ext->nsaddrs[nserv],
    688 					&set->sin6, size);
    689 			if (size <= sizeof(statp->nsaddr_list[nserv]))
    690 				memcpy(&statp->nsaddr_list[nserv],
    691 					&set->sin6, size);
    692 			else
    693 				statp->nsaddr_list[nserv].sin_family = 0;
    694 			nserv++;
    695 			break;
    696 #endif
    697 
    698 		default:
    699 			break;
    700 		}
    701 		set++;
    702 	}
    703 	statp->nscount = nserv;
    704 
    705 }
    706 
    707 int
    708 res_getservers(res_state statp, union res_sockaddr_union *set, int cnt) {
    709 	int i;
    710 	size_t size;
    711 	u_int16_t family;
    712 
    713 	for (i = 0; i < statp->nscount && i < cnt; i++) {
    714 		if (statp->_u._ext.ext)
    715 			family = statp->_u._ext.ext->nsaddrs[i].sin.sin_family;
    716 		else
    717 			family = statp->nsaddr_list[i].sin_family;
    718 
    719 		switch (family) {
    720 		case AF_INET:
    721 			size = sizeof(set->sin);
    722 			if (statp->_u._ext.ext)
    723 				memcpy(&set->sin,
    724 				       &statp->_u._ext.ext->nsaddrs[i],
    725 				       size);
    726 			else
    727 				memcpy(&set->sin, &statp->nsaddr_list[i],
    728 				       size);
    729 			break;
    730 
    731 #ifdef HAS_INET6_STRUCTS
    732 		case AF_INET6:
    733 			size = sizeof(set->sin6);
    734 			if (statp->_u._ext.ext)
    735 				memcpy(&set->sin6,
    736 				       &statp->_u._ext.ext->nsaddrs[i],
    737 				       size);
    738 			else
    739 				memcpy(&set->sin6, &statp->nsaddr_list[i],
    740 				       size);
    741 			break;
    742 #endif
    743 
    744 		default:
    745 			set->sin.sin_family = 0;
    746 			break;
    747 		}
    748 		set++;
    749 	}
    750 	return (statp->nscount);
    751 }
    752