xref: /freebsd/lib/libc/net/gethostbydns.c (revision af23369a6deaaeb612ab266eb88b8bb8d560c322)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * ++Copyright++ 1985, 1988, 1993
5  * -
6  * Copyright (c) 1985, 1988, 1993
7  *	The Regents of the University of California.  All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  * -
33  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
34  *
35  * Permission to use, copy, modify, and distribute this software for any
36  * purpose with or without fee is hereby granted, provided that the above
37  * copyright notice and this permission notice appear in all copies, and that
38  * the name of Digital Equipment Corporation not be used in advertising or
39  * publicity pertaining to distribution of the document or software without
40  * specific, written prior permission.
41  *
42  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
43  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
44  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
45  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
46  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
47  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
48  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
49  * SOFTWARE.
50  * -
51  * --Copyright--
52  */
53 
54 #if defined(LIBC_SCCS) && !defined(lint)
55 static char sccsid[] = "@(#)gethostnamadr.c	8.1 (Berkeley) 6/4/93";
56 static char fromrcsid[] = "From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $";
57 #endif /* LIBC_SCCS and not lint */
58 #include <sys/cdefs.h>
59 __FBSDID("$FreeBSD$");
60 
61 #include <sys/param.h>
62 #include <sys/socket.h>
63 #include <netinet/in.h>
64 #include <arpa/inet.h>
65 #include <arpa/nameser.h>
66 
67 #include <stdio.h>
68 #include <stdlib.h>
69 #include <unistd.h>
70 #include <string.h>
71 #include <netdb.h>
72 #include <resolv.h>
73 #include <ctype.h>
74 #include <errno.h>
75 #include <syslog.h>
76 #include <stdarg.h>
77 #include <nsswitch.h>
78 
79 #include "netdb_private.h"
80 #include "res_config.h"
81 
82 #define SPRINTF(x) ((size_t)sprintf x)
83 
84 static const char AskedForGot[] =
85 		"gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
86 
87 #ifdef RESOLVSORT
88 static void addrsort(char **, int, res_state);
89 #endif
90 
91 #ifdef DEBUG
92 static void dbg_printf(char *, int, res_state) __printflike(1, 0);
93 #endif
94 
95 #define MAXPACKET	(64*1024)
96 
97 typedef union {
98     HEADER hdr;
99     u_char buf[MAXPACKET];
100 } querybuf;
101 
102 typedef union {
103     int32_t al;
104     char ac;
105 } align;
106 
107 int _dns_ttl_;
108 
109 #ifdef DEBUG
110 static void
111 dbg_printf(char *msg, int num, res_state res)
112 {
113 	if (res->options & RES_DEBUG) {
114 		int save = errno;
115 
116 		printf(msg, num);
117 		errno = save;
118 	}
119 }
120 #else
121 # define dbg_printf(msg, num, res) /*nada*/
122 #endif
123 
124 #define BOUNDED_INCR(x) \
125 	do { \
126 		cp += x; \
127 		if (cp > eom) { \
128 			RES_SET_H_ERRNO(statp, NO_RECOVERY); \
129 			return (-1); \
130 		} \
131 	} while (0)
132 
133 #define BOUNDS_CHECK(ptr, count) \
134 	do { \
135 		if ((ptr) + (count) > eom) { \
136 			RES_SET_H_ERRNO(statp, NO_RECOVERY); \
137 			return (-1); \
138 		} \
139 	} while (0)
140 
141 static int
142 gethostanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
143     struct hostent *he, struct hostent_data *hed, res_state statp)
144 {
145 	const HEADER *hp;
146 	const u_char *cp;
147 	int n;
148 	const u_char *eom, *erdata;
149 	char *bp, *ep, **ap, **hap;
150 	int type, class, ancount, qdcount;
151 	int haveanswer, had_error;
152 	int toobig = 0;
153 	char tbuf[MAXDNAME];
154 	const char *tname;
155 	int (*name_ok)(const char *);
156 
157 	tname = qname;
158 	he->h_name = NULL;
159 	eom = answer->buf + anslen;
160 	switch (qtype) {
161 	case T_A:
162 	case T_AAAA:
163 		name_ok = res_hnok;
164 		break;
165 	case T_PTR:
166 		name_ok = res_dnok;
167 		break;
168 	default:
169 		RES_SET_H_ERRNO(statp, NO_RECOVERY);
170 		return (-1);	/* XXX should be abort(); */
171 	}
172 	/*
173 	 * find first satisfactory answer
174 	 */
175 	hp = &answer->hdr;
176 	ancount = ntohs(hp->ancount);
177 	qdcount = ntohs(hp->qdcount);
178 	bp = hed->hostbuf;
179 	ep = hed->hostbuf + sizeof hed->hostbuf;
180 	cp = answer->buf;
181 	BOUNDED_INCR(HFIXEDSZ);
182 	if (qdcount != 1) {
183 		RES_SET_H_ERRNO(statp, NO_RECOVERY);
184 		return (-1);
185 	}
186 	n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
187 	if ((n < 0) || !(*name_ok)(bp)) {
188 		RES_SET_H_ERRNO(statp, NO_RECOVERY);
189 		return (-1);
190 	}
191 	BOUNDED_INCR(n + QFIXEDSZ);
192 	if (qtype == T_A || qtype == T_AAAA) {
193 		/* res_send() has already verified that the query name is the
194 		 * same as the one we sent; this just gets the expanded name
195 		 * (i.e., with the succeeding search-domain tacked on).
196 		 */
197 		n = strlen(bp) + 1;		/* for the \0 */
198 		if (n >= MAXHOSTNAMELEN) {
199 			RES_SET_H_ERRNO(statp, NO_RECOVERY);
200 			return (-1);
201 		}
202 		he->h_name = bp;
203 		bp += n;
204 		/* The qname can be abbreviated, but h_name is now absolute. */
205 		qname = he->h_name;
206 	}
207 	ap = hed->host_aliases;
208 	*ap = NULL;
209 	he->h_aliases = hed->host_aliases;
210 	hap = hed->h_addr_ptrs;
211 	*hap = NULL;
212 	he->h_addr_list = hed->h_addr_ptrs;
213 	haveanswer = 0;
214 	had_error = 0;
215 	_dns_ttl_ = -1;
216 	while (ancount-- > 0 && cp < eom && !had_error) {
217 		n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
218 		if ((n < 0) || !(*name_ok)(bp)) {
219 			had_error++;
220 			continue;
221 		}
222 		cp += n;			/* name */
223 		BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
224 		type = _getshort(cp);
225  		cp += INT16SZ;			/* type */
226 		class = _getshort(cp);
227  		cp += INT16SZ;			/* class */
228 		if (qtype == T_A  && type == T_A)
229 			_dns_ttl_ = _getlong(cp);
230 		cp += INT32SZ;			/* TTL */
231 		n = _getshort(cp);
232 		cp += INT16SZ;			/* len */
233 		BOUNDS_CHECK(cp, n);
234 		erdata = cp + n;
235 		if (class != C_IN) {
236 			/* XXX - debug? syslog? */
237 			cp += n;
238 			continue;		/* XXX - had_error++ ? */
239 		}
240 		if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
241 			if (ap >= &hed->host_aliases[_MAXALIASES-1])
242 				continue;
243 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
244 			if ((n < 0) || !(*name_ok)(tbuf)) {
245 				had_error++;
246 				continue;
247 			}
248 			cp += n;
249 			if (cp != erdata) {
250 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
251 				return (-1);
252 			}
253 			/* Store alias. */
254 			*ap++ = bp;
255 			n = strlen(bp) + 1;	/* for the \0 */
256 			if (n >= MAXHOSTNAMELEN) {
257 				had_error++;
258 				continue;
259 			}
260 			bp += n;
261 			/* Get canonical name. */
262 			n = strlen(tbuf) + 1;	/* for the \0 */
263 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
264 				had_error++;
265 				continue;
266 			}
267 			strcpy(bp, tbuf);
268 			he->h_name = bp;
269 			bp += n;
270 			continue;
271 		}
272 		if (qtype == T_PTR && type == T_CNAME) {
273 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
274 			if (n < 0 || !res_dnok(tbuf)) {
275 				had_error++;
276 				continue;
277 			}
278 			cp += n;
279 			if (cp != erdata) {
280 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
281 				return (-1);
282 			}
283 			/* Get canonical name. */
284 			n = strlen(tbuf) + 1;	/* for the \0 */
285 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
286 				had_error++;
287 				continue;
288 			}
289 			strcpy(bp, tbuf);
290 			tname = bp;
291 			bp += n;
292 			continue;
293 		}
294 		if (type != qtype) {
295 #ifdef DEBUG
296 			if (type != T_KEY && type != T_SIG &&
297 			    type != T_DNAME && type != T_RRSIG)
298 				syslog(LOG_NOTICE|LOG_AUTH,
299 	"gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"",
300 				       qname, p_class(C_IN), p_type(qtype),
301 				       p_type(type));
302 #endif
303 			cp += n;
304 			continue;		/* XXX - had_error++ ? */
305 		}
306 		switch (type) {
307 		case T_PTR:
308 			if (strcasecmp(tname, bp) != 0) {
309 				syslog(LOG_NOTICE|LOG_AUTH,
310 				       AskedForGot, qname, bp);
311 				cp += n;
312 				continue;	/* XXX - had_error++ ? */
313 			}
314 			n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
315 			if ((n < 0) || !res_hnok(bp)) {
316 				had_error++;
317 				break;
318 			}
319 #if MULTI_PTRS_ARE_ALIASES
320 			cp += n;
321 			if (cp != erdata) {
322 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
323 				return (-1);
324 			}
325 			if (!haveanswer)
326 				he->h_name = bp;
327 			else if (ap < &hed->host_aliases[_MAXALIASES-1])
328 				*ap++ = bp;
329 			else
330 				n = -1;
331 			if (n != -1) {
332 				n = strlen(bp) + 1;	/* for the \0 */
333 				if (n >= MAXHOSTNAMELEN) {
334 					had_error++;
335 					break;
336 				}
337 				bp += n;
338 			}
339 			break;
340 #else
341 			he->h_name = bp;
342 			if (statp->options & RES_USE_INET6) {
343 				n = strlen(bp) + 1;	/* for the \0 */
344 				if (n >= MAXHOSTNAMELEN) {
345 					had_error++;
346 					break;
347 				}
348 				bp += n;
349 				_map_v4v6_hostent(he, &bp, ep);
350 			}
351 			RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
352 			return (0);
353 #endif
354 		case T_A:
355 		case T_AAAA:
356 			if (strcasecmp(he->h_name, bp) != 0) {
357 				syslog(LOG_NOTICE|LOG_AUTH,
358 				       AskedForGot, he->h_name, bp);
359 				cp += n;
360 				continue;	/* XXX - had_error++ ? */
361 			}
362 			if (n != he->h_length) {
363 				cp += n;
364 				continue;
365 			}
366 			if (!haveanswer) {
367 				int nn;
368 
369 				he->h_name = bp;
370 				nn = strlen(bp) + 1;	/* for the \0 */
371 				bp += nn;
372 			}
373 
374 			bp += sizeof(align) - ((u_long)bp % sizeof(align));
375 
376 			if (bp + n >= ep) {
377 				dbg_printf("size (%d) too big\n", n, statp);
378 				had_error++;
379 				continue;
380 			}
381 			if (hap >= &hed->h_addr_ptrs[_MAXADDRS-1]) {
382 				if (!toobig++)
383 					dbg_printf("Too many addresses (%d)\n",
384 						_MAXADDRS, statp);
385 				cp += n;
386 				continue;
387 			}
388 			memcpy(*hap++ = bp, cp, n);
389 			bp += n;
390 			cp += n;
391 			if (cp != erdata) {
392 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
393 				return (-1);
394 			}
395 			break;
396 		default:
397 			dbg_printf("Impossible condition (type=%d)\n", type,
398 			    statp);
399 			RES_SET_H_ERRNO(statp, NO_RECOVERY);
400 			return (-1);
401 			/* BIND has abort() here, too risky on bad data */
402 		}
403 		if (!had_error)
404 			haveanswer++;
405 	}
406 	if (haveanswer) {
407 		*ap = NULL;
408 		*hap = NULL;
409 # if defined(RESOLVSORT)
410 		/*
411 		 * Note: we sort even if host can take only one address
412 		 * in its return structures - should give it the "best"
413 		 * address in that case, not some random one
414 		 */
415 		if (statp->nsort && haveanswer > 1 && qtype == T_A)
416 			addrsort(hed->h_addr_ptrs, haveanswer, statp);
417 # endif /*RESOLVSORT*/
418 		if (!he->h_name) {
419 			n = strlen(qname) + 1;	/* for the \0 */
420 			if (n > ep - bp || n >= MAXHOSTNAMELEN)
421 				goto no_recovery;
422 			strcpy(bp, qname);
423 			he->h_name = bp;
424 			bp += n;
425 		}
426 		if (statp->options & RES_USE_INET6)
427 			_map_v4v6_hostent(he, &bp, ep);
428 		RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
429 		return (0);
430 	}
431  no_recovery:
432 	RES_SET_H_ERRNO(statp, NO_RECOVERY);
433 	return (-1);
434 }
435 
436 /* XXX: for async DNS resolver in ypserv */
437 struct hostent *
438 __dns_getanswer(const char *answer, int anslen, const char *qname, int qtype)
439 {
440 	struct hostent *he;
441 	struct hostent_data *hed;
442 	int error;
443 	res_state statp;
444 
445 	statp = __res_state();
446 	if ((he = __hostent_init()) == NULL ||
447 	    (hed = __hostent_data_init()) == NULL) {
448 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
449 		return (NULL);
450 	}
451 	switch (qtype) {
452 	case T_AAAA:
453 		he->h_addrtype = AF_INET6;
454 		he->h_length = NS_IN6ADDRSZ;
455 		break;
456 	case T_A:
457 	default:
458 		he->h_addrtype = AF_INET;
459 		he->h_length = NS_INADDRSZ;
460 		break;
461 	}
462 
463 	error = gethostanswer((const querybuf *)answer, anslen, qname, qtype,
464 	    he, hed, statp);
465 	return (error == 0) ? he : NULL;
466 }
467 
468 int
469 _dns_gethostbyname(void *rval, void *cb_data, va_list ap)
470 {
471 	const char *name;
472 	int af;
473 	char *buffer;
474 	size_t buflen;
475 	int *errnop, *h_errnop;
476 	struct hostent *hptr, he;
477 	struct hostent_data *hed;
478 	querybuf *buf;
479 	int n, type, error;
480 	res_state statp;
481 
482 	name = va_arg(ap, const char *);
483 	af = va_arg(ap, int);
484 	hptr = va_arg(ap, struct hostent *);
485 	buffer = va_arg(ap, char *);
486 	buflen = va_arg(ap, size_t);
487 	errnop = va_arg(ap, int *);
488 	h_errnop = va_arg(ap, int *);
489 
490 	*((struct hostent **)rval) = NULL;
491 
492 	statp = __res_state();
493 	if ((hed = __hostent_data_init()) == NULL) {
494 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
495 		*h_errnop = statp->res_h_errno;
496 		return (NS_NOTFOUND);
497 	}
498 
499 	he.h_addrtype = af;
500 	switch (af) {
501 	case AF_INET:
502 		he.h_length = NS_INADDRSZ;
503 		type = T_A;
504 		break;
505 	case AF_INET6:
506 		he.h_length = NS_IN6ADDRSZ;
507 		type = T_AAAA;
508 		break;
509 	default:
510 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
511 		*h_errnop = statp->res_h_errno;
512 		errno = EAFNOSUPPORT;
513 		return (NS_UNAVAIL);
514 	}
515 
516 	if ((buf = malloc(sizeof(*buf))) == NULL) {
517 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
518 		*h_errnop = statp->res_h_errno;
519 		return (NS_NOTFOUND);
520 	}
521 	n = res_nsearch(statp, name, C_IN, type, buf->buf, sizeof(buf->buf));
522 	if (n < 0) {
523 		free(buf);
524 		dbg_printf("res_nsearch failed (%d)\n", n, statp);
525 		*h_errnop = statp->res_h_errno;
526 		return (NS_NOTFOUND);
527 	} else if (n > sizeof(buf->buf)) {
528 		free(buf);
529 		dbg_printf("static buffer is too small (%d)\n", n, statp);
530 		*h_errnop = statp->res_h_errno;
531 		return (NS_UNAVAIL);
532 	}
533 	error = gethostanswer(buf, n, name, type, &he, hed, statp);
534 	free(buf);
535 	if (error != 0) {
536 		*h_errnop = statp->res_h_errno;
537 		switch (statp->res_h_errno) {
538 		case HOST_NOT_FOUND:
539 			return (NS_NOTFOUND);
540 		case TRY_AGAIN:
541 			return (NS_TRYAGAIN);
542 		default:
543 			return (NS_UNAVAIL);
544 		}
545 		/*NOTREACHED*/
546 	}
547 	if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
548 		*errnop = errno;
549 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
550 		*h_errnop = statp->res_h_errno;
551 		return (NS_RETURN);
552 	}
553 	RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
554 	*((struct hostent **)rval) = hptr;
555 	return (NS_SUCCESS);
556 }
557 
558 int
559 _dns_gethostbyaddr(void *rval, void *cb_data, va_list ap)
560 {
561 	const void *addr;
562 	socklen_t len;
563 	int af;
564 	char *buffer;
565 	size_t buflen;
566 	int *errnop, *h_errnop;
567 	const u_char *uaddr;
568 	struct hostent *hptr, he;
569 	struct hostent_data *hed;
570 	int n;
571 	querybuf *buf;
572 	char qbuf[MAXDNAME+1], *qp;
573 	res_state statp;
574 #ifdef SUNSECURITY
575 	struct hostdata rhd;
576 	struct hostent *rhe;
577 	char **haddr;
578 	u_long old_options;
579 	char hname2[MAXDNAME+1], numaddr[46];
580 	int ret_h_error;
581 #endif /*SUNSECURITY*/
582 
583 	addr = va_arg(ap, const void *);
584 	len = va_arg(ap, socklen_t);
585 	af = va_arg(ap, int);
586 	hptr = va_arg(ap, struct hostent *);
587 	buffer = va_arg(ap, char *);
588 	buflen = va_arg(ap, size_t);
589 	errnop = va_arg(ap, int *);
590 	h_errnop = va_arg(ap, int *);
591 	uaddr = (const u_char *)addr;
592 
593 	*((struct hostent **)rval) = NULL;
594 
595 	statp = __res_state();
596 	if ((hed = __hostent_data_init()) == NULL) {
597 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
598 		*h_errnop = statp->res_h_errno;
599 		return (NS_NOTFOUND);
600 	}
601 
602 	switch (af) {
603 	case AF_INET:
604 		(void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
605 			       (uaddr[3] & 0xff),
606 			       (uaddr[2] & 0xff),
607 			       (uaddr[1] & 0xff),
608 			       (uaddr[0] & 0xff));
609 		break;
610 	case AF_INET6:
611 		qp = qbuf;
612 		for (n = NS_IN6ADDRSZ - 1; n >= 0; n--) {
613 			qp += SPRINTF((qp, "%x.%x.",
614 				       uaddr[n] & 0xf,
615 				       (uaddr[n] >> 4) & 0xf));
616 		}
617 		strlcat(qbuf, "ip6.arpa", sizeof(qbuf));
618 		break;
619 	default:
620 		abort();
621 	}
622 	if ((buf = malloc(sizeof(*buf))) == NULL) {
623 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
624 		*h_errnop = statp->res_h_errno;
625 		return NS_NOTFOUND;
626 	}
627 	n = res_nquery(statp, qbuf, C_IN, T_PTR, (u_char *)buf->buf,
628 	    sizeof buf->buf);
629 	if (n < 0) {
630 		free(buf);
631 		dbg_printf("res_nquery failed (%d)\n", n, statp);
632 		*h_errnop = statp->res_h_errno;
633 		return (NS_UNAVAIL);
634 	}
635 	if (n > sizeof buf->buf) {
636 		free(buf);
637 		dbg_printf("static buffer is too small (%d)\n", n, statp);
638 		*h_errnop = statp->res_h_errno;
639 		return (NS_UNAVAIL);
640 	}
641 	if (gethostanswer(buf, n, qbuf, T_PTR, &he, hed, statp) != 0) {
642 		free(buf);
643 		*h_errnop = statp->res_h_errno;
644 		switch (statp->res_h_errno) {
645 		case HOST_NOT_FOUND:
646 			return (NS_NOTFOUND);
647 		case TRY_AGAIN:
648 			return (NS_TRYAGAIN);
649 		default:
650 			return (NS_UNAVAIL);
651 		}
652 		/*NOTREACHED*/
653 	}
654 	free(buf);
655 #ifdef SUNSECURITY
656 	if (af == AF_INET) {
657 	    /*
658 	     * turn off search as the name should be absolute,
659 	     * 'localhost' should be matched by defnames
660 	     */
661 	    strncpy(hname2, he.h_name, MAXDNAME);
662 	    hname2[MAXDNAME] = '\0';
663 	    old_options = statp->options;
664 	    statp->options &= ~RES_DNSRCH;
665 	    statp->options |= RES_DEFNAMES;
666 	    memset(&rhd, 0, sizeof rhd);
667 	    rhe = gethostbyname_r(hname2, &rhd.host, &rhd.data,
668 	        sizeof(rhd.data), &ret_h_error);
669 	    if (rhe == NULL) {
670 		if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
671 		    strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
672 		syslog(LOG_NOTICE|LOG_AUTH,
673 		       "gethostbyaddr: No A record for %s (verifying [%s])",
674 		       hname2, numaddr);
675 		statp->options = old_options;
676 		RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
677 		*h_errnop = statp->res_h_errno;
678 		return (NS_NOTFOUND);
679 	    }
680 	    statp->options = old_options;
681 	    for (haddr = rhe->h_addr_list; *haddr; haddr++)
682 		if (!memcmp(*haddr, addr, NS_INADDRSZ))
683 			break;
684 	    if (!*haddr) {
685 		if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
686 		    strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
687 		syslog(LOG_NOTICE|LOG_AUTH,
688 		       "gethostbyaddr: A record of %s != PTR record [%s]",
689 		       hname2, numaddr);
690 		RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
691 		*h_errnop = statp->res_h_errno;
692 		return (NS_NOTFOUND);
693 	    }
694 	}
695 #endif /*SUNSECURITY*/
696 	he.h_addrtype = af;
697 	he.h_length = len;
698 	memcpy(hed->host_addr, uaddr, len);
699 	hed->h_addr_ptrs[0] = (char *)hed->host_addr;
700 	hed->h_addr_ptrs[1] = NULL;
701 	if (af == AF_INET && (statp->options & RES_USE_INET6)) {
702 		_map_v4v6_address((char*)hed->host_addr, (char*)hed->host_addr);
703 		he.h_addrtype = AF_INET6;
704 		he.h_length = NS_IN6ADDRSZ;
705 	}
706 	if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
707 		*errnop = errno;
708 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
709 		*h_errnop = statp->res_h_errno;
710 		return (NS_RETURN);
711 	}
712 	RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
713 	*((struct hostent **)rval) = hptr;
714 	return (NS_SUCCESS);
715 }
716 
717 #ifdef RESOLVSORT
718 static void
719 addrsort(char **ap, int num, res_state res)
720 {
721 	int i, j;
722 	char **p;
723 	short aval[_MAXADDRS];
724 	int needsort = 0;
725 
726 	p = ap;
727 	for (i = 0; i < num; i++, p++) {
728 	    for (j = 0 ; (unsigned)j < res->nsort; j++)
729 		if (res->sort_list[j].addr.s_addr ==
730 		    (((struct in_addr *)(*p))->s_addr & res->sort_list[j].mask))
731 			break;
732 	    aval[i] = j;
733 	    if (needsort == 0 && i > 0 && j < aval[i-1])
734 		needsort = i;
735 	}
736 	if (!needsort)
737 	    return;
738 
739 	while (needsort < num) {
740 	    for (j = needsort - 1; j >= 0; j--) {
741 		if (aval[j] > aval[j+1]) {
742 		    char *hp;
743 
744 		    i = aval[j];
745 		    aval[j] = aval[j+1];
746 		    aval[j+1] = i;
747 
748 		    hp = ap[j];
749 		    ap[j] = ap[j+1];
750 		    ap[j+1] = hp;
751 
752 		} else
753 		    break;
754 	    }
755 	    needsort++;
756 	}
757 }
758 #endif
759 
760 void
761 _sethostdnsent(int stayopen)
762 {
763 	res_state statp;
764 
765 	statp = __res_state();
766 	if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1)
767 		return;
768 	if (stayopen)
769 		statp->options |= RES_STAYOPEN | RES_USEVC;
770 }
771 
772 void
773 _endhostdnsent(void)
774 {
775 	res_state statp;
776 
777 	statp = __res_state();
778 	statp->options &= ~(RES_STAYOPEN | RES_USEVC);
779 	res_nclose(statp);
780 }
781