xref: /freebsd/lib/libc/net/gethostbydns.c (revision 49b49cda41feabe3439f7318e8bf40e3896c7bf4)
1 /*
2  * ++Copyright++ 1985, 1988, 1993
3  * -
4  * Copyright (c) 1985, 1988, 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  * 4. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  * -
31  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
32  *
33  * Permission to use, copy, modify, and distribute this software for any
34  * purpose with or without fee is hereby granted, provided that the above
35  * copyright notice and this permission notice appear in all copies, and that
36  * the name of Digital Equipment Corporation not be used in advertising or
37  * publicity pertaining to distribution of the document or software without
38  * specific, written prior permission.
39  *
40  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
41  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
42  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
43  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
44  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
45  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
46  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
47  * SOFTWARE.
48  * -
49  * --Copyright--
50  */
51 
52 #if defined(LIBC_SCCS) && !defined(lint)
53 static char sccsid[] = "@(#)gethostnamadr.c	8.1 (Berkeley) 6/4/93";
54 static char fromrcsid[] = "From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $";
55 #endif /* LIBC_SCCS and not lint */
56 #include <sys/cdefs.h>
57 __FBSDID("$FreeBSD$");
58 
59 #include <sys/types.h>
60 #include <sys/param.h>
61 #include <sys/socket.h>
62 #include <netinet/in.h>
63 #include <arpa/inet.h>
64 #include <arpa/nameser.h>
65 
66 #include <stdio.h>
67 #include <stdlib.h>
68 #include <unistd.h>
69 #include <string.h>
70 #include <netdb.h>
71 #include <resolv.h>
72 #include <ctype.h>
73 #include <errno.h>
74 #include <syslog.h>
75 #include <stdarg.h>
76 #include <nsswitch.h>
77 
78 #include "netdb_private.h"
79 #include "res_config.h"
80 
81 #define SPRINTF(x) ((size_t)sprintf x)
82 
83 static const char AskedForGot[] =
84 		"gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
85 
86 #ifdef RESOLVSORT
87 static void addrsort(char **, int, res_state);
88 #endif
89 
90 #ifdef DEBUG
91 static void dprintf(char *, int, res_state) __printflike(1, 0);
92 #endif
93 
94 #define MAXPACKET	(64*1024)
95 
96 typedef union {
97     HEADER hdr;
98     u_char buf[MAXPACKET];
99 } querybuf;
100 
101 typedef union {
102     int32_t al;
103     char ac;
104 } align;
105 
106 int _dns_ttl_;
107 
108 #ifdef DEBUG
109 static void
110 dprintf(char *msg, int num, res_state res)
111 {
112 	if (res->options & RES_DEBUG) {
113 		int save = errno;
114 
115 		printf(msg, num);
116 		errno = save;
117 	}
118 }
119 #else
120 # define dprintf(msg, num, res) /*nada*/
121 #endif
122 
123 #define BOUNDED_INCR(x) \
124 	do { \
125 		cp += x; \
126 		if (cp > eom) { \
127 			RES_SET_H_ERRNO(statp, NO_RECOVERY); \
128 			return (-1); \
129 		} \
130 	} while (0)
131 
132 #define BOUNDS_CHECK(ptr, count) \
133 	do { \
134 		if ((ptr) + (count) > eom) { \
135 			RES_SET_H_ERRNO(statp, NO_RECOVERY); \
136 			return (-1); \
137 		} \
138 	} while (0)
139 
140 static int
141 gethostanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
142     struct hostent *he, struct hostent_data *hed, res_state statp)
143 {
144 	const HEADER *hp;
145 	const u_char *cp;
146 	int n;
147 	const u_char *eom, *erdata;
148 	char *bp, *ep, **ap, **hap;
149 	int type, class, ancount, qdcount;
150 	int haveanswer, had_error;
151 	int toobig = 0;
152 	char tbuf[MAXDNAME];
153 	const char *tname;
154 	int (*name_ok)(const char *);
155 
156 	tname = qname;
157 	he->h_name = NULL;
158 	eom = answer->buf + anslen;
159 	switch (qtype) {
160 	case T_A:
161 	case T_AAAA:
162 		name_ok = res_hnok;
163 		break;
164 	case T_PTR:
165 		name_ok = res_dnok;
166 		break;
167 	default:
168 		RES_SET_H_ERRNO(statp, NO_RECOVERY);
169 		return (-1);	/* XXX should be abort(); */
170 	}
171 	/*
172 	 * find first satisfactory answer
173 	 */
174 	hp = &answer->hdr;
175 	ancount = ntohs(hp->ancount);
176 	qdcount = ntohs(hp->qdcount);
177 	bp = hed->hostbuf;
178 	ep = hed->hostbuf + sizeof hed->hostbuf;
179 	cp = answer->buf;
180 	BOUNDED_INCR(HFIXEDSZ);
181 	if (qdcount != 1) {
182 		RES_SET_H_ERRNO(statp, NO_RECOVERY);
183 		return (-1);
184 	}
185 	n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
186 	if ((n < 0) || !(*name_ok)(bp)) {
187 		RES_SET_H_ERRNO(statp, NO_RECOVERY);
188 		return (-1);
189 	}
190 	BOUNDED_INCR(n + QFIXEDSZ);
191 	if (qtype == T_A || qtype == T_AAAA) {
192 		/* res_send() has already verified that the query name is the
193 		 * same as the one we sent; this just gets the expanded name
194 		 * (i.e., with the succeeding search-domain tacked on).
195 		 */
196 		n = strlen(bp) + 1;		/* for the \0 */
197 		if (n >= MAXHOSTNAMELEN) {
198 			RES_SET_H_ERRNO(statp, NO_RECOVERY);
199 			return (-1);
200 		}
201 		he->h_name = bp;
202 		bp += n;
203 		/* The qname can be abbreviated, but h_name is now absolute. */
204 		qname = he->h_name;
205 	}
206 	ap = hed->host_aliases;
207 	*ap = NULL;
208 	he->h_aliases = hed->host_aliases;
209 	hap = hed->h_addr_ptrs;
210 	*hap = NULL;
211 	he->h_addr_list = hed->h_addr_ptrs;
212 	haveanswer = 0;
213 	had_error = 0;
214 	_dns_ttl_ = -1;
215 	while (ancount-- > 0 && cp < eom && !had_error) {
216 		n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
217 		if ((n < 0) || !(*name_ok)(bp)) {
218 			had_error++;
219 			continue;
220 		}
221 		cp += n;			/* name */
222 		BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
223 		type = _getshort(cp);
224  		cp += INT16SZ;			/* type */
225 		class = _getshort(cp);
226  		cp += INT16SZ;			/* class */
227 		if (qtype == T_A  && type == T_A)
228 			_dns_ttl_ = _getlong(cp);
229 		cp += INT32SZ;			/* TTL */
230 		n = _getshort(cp);
231 		cp += INT16SZ;			/* len */
232 		BOUNDS_CHECK(cp, n);
233 		erdata = cp + n;
234 		if (class != C_IN) {
235 			/* XXX - debug? syslog? */
236 			cp += n;
237 			continue;		/* XXX - had_error++ ? */
238 		}
239 		if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
240 			if (ap >= &hed->host_aliases[_MAXALIASES-1])
241 				continue;
242 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
243 			if ((n < 0) || !(*name_ok)(tbuf)) {
244 				had_error++;
245 				continue;
246 			}
247 			cp += n;
248 			if (cp != erdata) {
249 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
250 				return (-1);
251 			}
252 			/* Store alias. */
253 			*ap++ = bp;
254 			n = strlen(bp) + 1;	/* for the \0 */
255 			if (n >= MAXHOSTNAMELEN) {
256 				had_error++;
257 				continue;
258 			}
259 			bp += n;
260 			/* Get canonical name. */
261 			n = strlen(tbuf) + 1;	/* for the \0 */
262 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
263 				had_error++;
264 				continue;
265 			}
266 			strcpy(bp, tbuf);
267 			he->h_name = bp;
268 			bp += n;
269 			continue;
270 		}
271 		if (qtype == T_PTR && type == T_CNAME) {
272 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
273 			if (n < 0 || !res_dnok(tbuf)) {
274 				had_error++;
275 				continue;
276 			}
277 			cp += n;
278 			if (cp != erdata) {
279 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
280 				return (-1);
281 			}
282 			/* Get canonical name. */
283 			n = strlen(tbuf) + 1;	/* for the \0 */
284 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
285 				had_error++;
286 				continue;
287 			}
288 			strcpy(bp, tbuf);
289 			tname = bp;
290 			bp += n;
291 			continue;
292 		}
293 		if (type != qtype) {
294 			if (type != T_SIG && type != ns_t_dname)
295 				syslog(LOG_NOTICE|LOG_AUTH,
296 	"gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"",
297 				       qname, p_class(C_IN), p_type(qtype),
298 				       p_type(type));
299 			cp += n;
300 			continue;		/* XXX - had_error++ ? */
301 		}
302 		switch (type) {
303 		case T_PTR:
304 			if (strcasecmp(tname, bp) != 0) {
305 				syslog(LOG_NOTICE|LOG_AUTH,
306 				       AskedForGot, qname, bp);
307 				cp += n;
308 				continue;	/* XXX - had_error++ ? */
309 			}
310 			n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
311 			if ((n < 0) || !res_hnok(bp)) {
312 				had_error++;
313 				break;
314 			}
315 #if MULTI_PTRS_ARE_ALIASES
316 			cp += n;
317 			if (cp != erdata) {
318 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
319 				return (-1);
320 			}
321 			if (!haveanswer)
322 				he->h_name = bp;
323 			else if (ap < &hed->host_aliases[_MAXALIASES-1])
324 				*ap++ = bp;
325 			else
326 				n = -1;
327 			if (n != -1) {
328 				n = strlen(bp) + 1;	/* for the \0 */
329 				if (n >= MAXHOSTNAMELEN) {
330 					had_error++;
331 					break;
332 				}
333 				bp += n;
334 			}
335 			break;
336 #else
337 			he->h_name = bp;
338 			if (statp->options & RES_USE_INET6) {
339 				n = strlen(bp) + 1;	/* for the \0 */
340 				if (n >= MAXHOSTNAMELEN) {
341 					had_error++;
342 					break;
343 				}
344 				bp += n;
345 				_map_v4v6_hostent(he, &bp, ep);
346 			}
347 			RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
348 			return (0);
349 #endif
350 		case T_A:
351 		case T_AAAA:
352 			if (strcasecmp(he->h_name, bp) != 0) {
353 				syslog(LOG_NOTICE|LOG_AUTH,
354 				       AskedForGot, he->h_name, bp);
355 				cp += n;
356 				continue;	/* XXX - had_error++ ? */
357 			}
358 			if (n != he->h_length) {
359 				cp += n;
360 				continue;
361 			}
362 			if (!haveanswer) {
363 				int nn;
364 
365 				he->h_name = bp;
366 				nn = strlen(bp) + 1;	/* for the \0 */
367 				bp += nn;
368 			}
369 
370 			bp += sizeof(align) - ((u_long)bp % sizeof(align));
371 
372 			if (bp + n >= ep) {
373 				dprintf("size (%d) too big\n", n, statp);
374 				had_error++;
375 				continue;
376 			}
377 			if (hap >= &hed->h_addr_ptrs[_MAXADDRS-1]) {
378 				if (!toobig++)
379 					dprintf("Too many addresses (%d)\n",
380 						_MAXADDRS, statp);
381 				cp += n;
382 				continue;
383 			}
384 			memcpy(*hap++ = bp, cp, n);
385 			bp += n;
386 			cp += n;
387 			if (cp != erdata) {
388 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
389 				return (-1);
390 			}
391 			break;
392 		default:
393 			dprintf("Impossible condition (type=%d)\n", type,
394 			    statp);
395 			RES_SET_H_ERRNO(statp, NO_RECOVERY);
396 			return (-1);
397 			/* BIND has abort() here, too risky on bad data */
398 		}
399 		if (!had_error)
400 			haveanswer++;
401 	}
402 	if (haveanswer) {
403 		*ap = NULL;
404 		*hap = NULL;
405 # if defined(RESOLVSORT)
406 		/*
407 		 * Note: we sort even if host can take only one address
408 		 * in its return structures - should give it the "best"
409 		 * address in that case, not some random one
410 		 */
411 		if (statp->nsort && haveanswer > 1 && qtype == T_A)
412 			addrsort(hed->h_addr_ptrs, haveanswer, statp);
413 # endif /*RESOLVSORT*/
414 		if (!he->h_name) {
415 			n = strlen(qname) + 1;	/* for the \0 */
416 			if (n > ep - bp || n >= MAXHOSTNAMELEN)
417 				goto no_recovery;
418 			strcpy(bp, qname);
419 			he->h_name = bp;
420 			bp += n;
421 		}
422 		if (statp->options & RES_USE_INET6)
423 			_map_v4v6_hostent(he, &bp, ep);
424 		RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
425 		return (0);
426 	}
427  no_recovery:
428 	RES_SET_H_ERRNO(statp, NO_RECOVERY);
429 	return (-1);
430 }
431 
432 /* XXX: for async DNS resolver in ypserv */
433 struct hostent *
434 __dns_getanswer(const char *answer, int anslen, const char *qname, int qtype)
435 {
436 	struct hostent *he;
437 	struct hostent_data *hed;
438 	int error;
439 	res_state statp;
440 
441 	statp = __res_state();
442 	if ((he = __hostent_init()) == NULL ||
443 	    (hed = __hostent_data_init()) == NULL) {
444 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
445 		return (NULL);
446 	}
447 	switch (qtype) {
448 	case T_AAAA:
449 		he->h_addrtype = AF_INET6;
450 		he->h_length = NS_IN6ADDRSZ;
451 		break;
452 	case T_A:
453 	default:
454 		he->h_addrtype = AF_INET;
455 		he->h_length = NS_INADDRSZ;
456 		break;
457 	}
458 
459 	error = gethostanswer((const querybuf *)answer, anslen, qname, qtype,
460 	    he, hed, statp);
461 	return (error == 0) ? he : NULL;
462 }
463 
464 int
465 _dns_gethostbyname(void *rval, void *cb_data, va_list ap)
466 {
467 	const char *name;
468 	int af;
469 	char *buffer;
470 	size_t buflen;
471 	int *errnop, *h_errnop;
472 	struct hostent *hptr, he;
473 	struct hostent_data *hed;
474 	querybuf *buf;
475 	int n, type, error;
476 	res_state statp;
477 
478 	name = va_arg(ap, const char *);
479 	af = va_arg(ap, int);
480 	hptr = va_arg(ap, struct hostent *);
481 	buffer = va_arg(ap, char *);
482 	buflen = va_arg(ap, size_t);
483 	errnop = va_arg(ap, int *);
484 	h_errnop = va_arg(ap, int *);
485 
486 	*((struct hostent **)rval) = NULL;
487 
488 	statp = __res_state();
489 	if ((hed = __hostent_data_init()) == NULL) {
490 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
491 		*h_errnop = statp->res_h_errno;
492 		return (NS_NOTFOUND);
493 	}
494 
495 	he.h_addrtype = af;
496 	switch (af) {
497 	case AF_INET:
498 		he.h_length = NS_INADDRSZ;
499 		type = T_A;
500 		break;
501 	case AF_INET6:
502 		he.h_length = NS_IN6ADDRSZ;
503 		type = T_AAAA;
504 		break;
505 	default:
506 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
507 		*h_errnop = statp->res_h_errno;
508 		errno = EAFNOSUPPORT;
509 		return (NS_UNAVAIL);
510 	}
511 
512 	if ((buf = malloc(sizeof(*buf))) == NULL) {
513 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
514 		*h_errnop = statp->res_h_errno;
515 		return (NS_NOTFOUND);
516 	}
517 	n = res_nsearch(statp, name, C_IN, type, buf->buf, sizeof(buf->buf));
518 	if (n < 0) {
519 		free(buf);
520 		dprintf("res_nsearch failed (%d)\n", n, statp);
521 		*h_errnop = statp->res_h_errno;
522 		return (NS_NOTFOUND);
523 	} else if (n > sizeof(buf->buf)) {
524 		free(buf);
525 		dprintf("static buffer is too small (%d)\n", n, statp);
526 		*h_errnop = statp->res_h_errno;
527 		return (NS_UNAVAIL);
528 	}
529 	error = gethostanswer(buf, n, name, type, &he, hed, statp);
530 	free(buf);
531 	if (error != 0) {
532 		*h_errnop = statp->res_h_errno;
533 		switch (statp->res_h_errno) {
534 		case HOST_NOT_FOUND:
535 			return (NS_NOTFOUND);
536 		case TRY_AGAIN:
537 			return (NS_TRYAGAIN);
538 		default:
539 			return (NS_UNAVAIL);
540 		}
541 		/*NOTREACHED*/
542 	}
543 	if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
544 		*errnop = errno;
545 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
546 		*h_errnop = statp->res_h_errno;
547 		return (NS_RETURN);
548 	}
549 	RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
550 	*((struct hostent **)rval) = hptr;
551 	return (NS_SUCCESS);
552 }
553 
554 int
555 _dns_gethostbyaddr(void *rval, void *cb_data, va_list ap)
556 {
557 	const void *addr;
558 	socklen_t len;
559 	int af;
560 	char *buffer;
561 	size_t buflen;
562 	int *errnop, *h_errnop;
563 	const u_char *uaddr;
564 	struct hostent *hptr, he;
565 	struct hostent_data *hed;
566 	int n;
567 	querybuf *buf;
568 	char qbuf[MAXDNAME+1], *qp;
569 	res_state statp;
570 #ifdef SUNSECURITY
571 	struct hostdata rhd;
572 	struct hostent *rhe;
573 	char **haddr;
574 	u_long old_options;
575 	char hname2[MAXDNAME+1], numaddr[46];
576 	int ret_h_error;
577 #endif /*SUNSECURITY*/
578 
579 	addr = va_arg(ap, const void *);
580 	len = va_arg(ap, socklen_t);
581 	af = va_arg(ap, int);
582 	hptr = va_arg(ap, struct hostent *);
583 	buffer = va_arg(ap, char *);
584 	buflen = va_arg(ap, size_t);
585 	errnop = va_arg(ap, int *);
586 	h_errnop = va_arg(ap, int *);
587 	uaddr = (const u_char *)addr;
588 
589 	*((struct hostent **)rval) = NULL;
590 
591 	statp = __res_state();
592 	if ((hed = __hostent_data_init()) == NULL) {
593 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
594 		*h_errnop = statp->res_h_errno;
595 		return (NS_NOTFOUND);
596 	}
597 
598 	switch (af) {
599 	case AF_INET:
600 		(void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
601 			       (uaddr[3] & 0xff),
602 			       (uaddr[2] & 0xff),
603 			       (uaddr[1] & 0xff),
604 			       (uaddr[0] & 0xff));
605 		break;
606 	case AF_INET6:
607 		qp = qbuf;
608 		for (n = NS_IN6ADDRSZ - 1; n >= 0; n--) {
609 			qp += SPRINTF((qp, "%x.%x.",
610 				       uaddr[n] & 0xf,
611 				       (uaddr[n] >> 4) & 0xf));
612 		}
613 		strlcat(qbuf, "ip6.arpa", sizeof(qbuf));
614 		break;
615 	default:
616 		abort();
617 	}
618 	if ((buf = malloc(sizeof(*buf))) == NULL) {
619 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
620 		*h_errnop = statp->res_h_errno;
621 		return NS_NOTFOUND;
622 	}
623 	n = res_nquery(statp, qbuf, C_IN, T_PTR, (u_char *)buf->buf,
624 	    sizeof buf->buf);
625 	if (n < 0) {
626 		free(buf);
627 		dprintf("res_nquery failed (%d)\n", n, statp);
628 		*h_errnop = statp->res_h_errno;
629 		return (NS_UNAVAIL);
630 	}
631 	if (n > sizeof buf->buf) {
632 		free(buf);
633 		dprintf("static buffer is too small (%d)\n", n, statp);
634 		*h_errnop = statp->res_h_errno;
635 		return (NS_UNAVAIL);
636 	}
637 	if (gethostanswer(buf, n, qbuf, T_PTR, &he, hed, statp) != 0) {
638 		free(buf);
639 		*h_errnop = statp->res_h_errno;
640 		switch (statp->res_h_errno) {
641 		case HOST_NOT_FOUND:
642 			return (NS_NOTFOUND);
643 		case TRY_AGAIN:
644 			return (NS_TRYAGAIN);
645 		default:
646 			return (NS_UNAVAIL);
647 		}
648 		/*NOTREACHED*/
649 	}
650 	free(buf);
651 #ifdef SUNSECURITY
652 	if (af == AF_INET) {
653 	    /*
654 	     * turn off search as the name should be absolute,
655 	     * 'localhost' should be matched by defnames
656 	     */
657 	    strncpy(hname2, he.h_name, MAXDNAME);
658 	    hname2[MAXDNAME] = '\0';
659 	    old_options = statp->options;
660 	    statp->options &= ~RES_DNSRCH;
661 	    statp->options |= RES_DEFNAMES;
662 	    memset(&rhd, 0, sizeof rhd);
663 	    rhe = gethostbyname_r(hname2, &rhd.host, &rhd.data,
664 	        sizeof(rhd.data), &ret_h_error);
665 	    if (rhe == NULL) {
666 		if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
667 		    strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
668 		syslog(LOG_NOTICE|LOG_AUTH,
669 		       "gethostbyaddr: No A record for %s (verifying [%s])",
670 		       hname2, numaddr);
671 		statp->options = old_options;
672 		RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
673 		*h_errnop = statp->res_h_errno;
674 		return (NS_NOTFOUND);
675 	    }
676 	    statp->options = old_options;
677 	    for (haddr = rhe->h_addr_list; *haddr; haddr++)
678 		if (!memcmp(*haddr, addr, NS_INADDRSZ))
679 			break;
680 	    if (!*haddr) {
681 		if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
682 		    strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
683 		syslog(LOG_NOTICE|LOG_AUTH,
684 		       "gethostbyaddr: A record of %s != PTR record [%s]",
685 		       hname2, numaddr);
686 		RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
687 		*h_errnop = statp->res_h_errno;
688 		return (NS_NOTFOUND);
689 	    }
690 	}
691 #endif /*SUNSECURITY*/
692 	he.h_addrtype = af;
693 	he.h_length = len;
694 	memcpy(hed->host_addr, uaddr, len);
695 	hed->h_addr_ptrs[0] = (char *)hed->host_addr;
696 	hed->h_addr_ptrs[1] = NULL;
697 	if (af == AF_INET && (statp->options & RES_USE_INET6)) {
698 		_map_v4v6_address((char*)hed->host_addr, (char*)hed->host_addr);
699 		he.h_addrtype = AF_INET6;
700 		he.h_length = NS_IN6ADDRSZ;
701 	}
702 	if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
703 		*errnop = errno;
704 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
705 		*h_errnop = statp->res_h_errno;
706 		return (NS_RETURN);
707 	}
708 	RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
709 	*((struct hostent **)rval) = hptr;
710 	return (NS_SUCCESS);
711 }
712 
713 #ifdef RESOLVSORT
714 static void
715 addrsort(char **ap, int num, res_state res)
716 {
717 	int i, j;
718 	char **p;
719 	short aval[_MAXADDRS];
720 	int needsort = 0;
721 
722 	p = ap;
723 	for (i = 0; i < num; i++, p++) {
724 	    for (j = 0 ; (unsigned)j < res->nsort; j++)
725 		if (res->sort_list[j].addr.s_addr ==
726 		    (((struct in_addr *)(*p))->s_addr & res->sort_list[j].mask))
727 			break;
728 	    aval[i] = j;
729 	    if (needsort == 0 && i > 0 && j < aval[i-1])
730 		needsort = i;
731 	}
732 	if (!needsort)
733 	    return;
734 
735 	while (needsort < num) {
736 	    for (j = needsort - 1; j >= 0; j--) {
737 		if (aval[j] > aval[j+1]) {
738 		    char *hp;
739 
740 		    i = aval[j];
741 		    aval[j] = aval[j+1];
742 		    aval[j+1] = i;
743 
744 		    hp = ap[j];
745 		    ap[j] = ap[j+1];
746 		    ap[j+1] = hp;
747 
748 		} else
749 		    break;
750 	    }
751 	    needsort++;
752 	}
753 }
754 #endif
755 
756 void
757 _sethostdnsent(int stayopen)
758 {
759 	res_state statp;
760 
761 	statp = __res_state();
762 	if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1)
763 		return;
764 	if (stayopen)
765 		statp->options |= RES_STAYOPEN | RES_USEVC;
766 }
767 
768 void
769 _endhostdnsent(void)
770 {
771 	res_state statp;
772 
773 	statp = __res_state();
774 	statp->options &= ~(RES_STAYOPEN | RES_USEVC);
775 	res_nclose(statp);
776 }
777