xref: /dragonfly/lib/libc/net/gethostbydns.c (revision cae2835b)
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  * 3. 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  * @(#)gethostnamadr.c	8.1 (Berkeley) 6/4/93
52  * From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $
53  * $FreeBSD: src/lib/libc/net/gethostbydns.c,v 1.58 2007/01/09 00:28:02 imp Exp $
54  */
55 
56 #include <sys/types.h>
57 #include <sys/param.h>
58 #include <sys/socket.h>
59 #include <netinet/in.h>
60 #include <arpa/inet.h>
61 #include <arpa/nameser.h>
62 
63 #include <stdio.h>
64 #include <stdlib.h>
65 #include <unistd.h>
66 #include <string.h>
67 #include <netdb.h>
68 #include <resolv.h>
69 #include <ctype.h>
70 #include <errno.h>
71 #include <syslog.h>
72 #include <stdarg.h>
73 #include <nsswitch.h>
74 
75 #include "netdb_private.h"
76 #include "res_config.h"
77 
78 #define SPRINTF(x) ((size_t)sprintf x)
79 
80 static const char AskedForGot[] =
81 		"gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
82 
83 #ifdef RESOLVSORT
84 static void addrsort(char **, int, res_state);
85 #endif
86 
87 #ifdef DEBUG
88 static void dbg_printf(char *, int, res_state) __printflike(1, 0);
89 #endif
90 
91 #define MAXPACKET	(64*1024)
92 
93 typedef union {
94     HEADER hdr;
95     u_char buf[MAXPACKET];
96 } querybuf;
97 
98 typedef union {
99     int32_t al;
100     char ac;
101 } align;
102 
103 int _dns_ttl_;
104 
105 #ifdef DEBUG
106 static void
107 dbg_printf(char *msg, int num, res_state res)
108 {
109 	if (res->options & RES_DEBUG) {
110 		int save = errno;
111 
112 		printf(msg, num);
113 		errno = save;
114 	}
115 }
116 #else
117 # define dbg_printf(msg, num, res) /*nada*/
118 #endif
119 
120 #define BOUNDED_INCR(x) \
121 	do { \
122 		cp += x; \
123 		if (cp > eom) { \
124 			RES_SET_H_ERRNO(statp, NO_RECOVERY); \
125 			return (-1); \
126 		} \
127 	} while (0)
128 
129 #define BOUNDS_CHECK(ptr, count) \
130 	do { \
131 		if ((ptr) + (count) > eom) { \
132 			RES_SET_H_ERRNO(statp, NO_RECOVERY); \
133 			return (-1); \
134 		} \
135 	} while (0)
136 
137 static int
138 gethostanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
139 	      struct hostent *he, struct hostent_data *hed, res_state statp)
140 {
141 	const HEADER *hp;
142 	const u_char *cp;
143 	int n;
144 	const u_char *eom, *erdata;
145 	char *bp, *ep, **ap, **hap;
146 	int type, class, ancount, qdcount;
147 	int haveanswer, had_error;
148 	int toobig = 0;
149 	char tbuf[MAXDNAME];
150 	const char *tname;
151 	int (*name_ok)(const char *);
152 
153 	tname = qname;
154 	he->h_name = NULL;
155 	eom = answer->buf + anslen;
156 	switch (qtype) {
157 	case T_A:
158 	case T_AAAA:
159 		name_ok = res_hnok;
160 		break;
161 	case T_PTR:
162 		name_ok = res_dnok;
163 		break;
164 	default:
165 		RES_SET_H_ERRNO(statp, NO_RECOVERY);
166 		return (-1);	/* XXX should be abort(); */
167 	}
168 	/*
169 	 * find first satisfactory answer
170 	 */
171 	hp = &answer->hdr;
172 	ancount = ntohs(hp->ancount);
173 	qdcount = ntohs(hp->qdcount);
174 	bp = hed->hostbuf;
175 	ep = hed->hostbuf + sizeof hed->hostbuf;
176 	cp = answer->buf;
177 	BOUNDED_INCR(HFIXEDSZ);
178 	if (qdcount != 1) {
179 		RES_SET_H_ERRNO(statp, NO_RECOVERY);
180 		return (-1);
181 	}
182 	n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
183 	if ((n < 0) || !(*name_ok)(bp)) {
184 		RES_SET_H_ERRNO(statp, NO_RECOVERY);
185 		return (-1);
186 	}
187 	BOUNDED_INCR(n + QFIXEDSZ);
188 	if (qtype == T_A || qtype == T_AAAA) {
189 		/* res_send() has already verified that the query name is the
190 		 * same as the one we sent; this just gets the expanded name
191 		 * (i.e., with the succeeding search-domain tacked on).
192 		 */
193 		n = strlen(bp) + 1;		/* for the \0 */
194 		if (n >= MAXHOSTNAMELEN) {
195 			RES_SET_H_ERRNO(statp, NO_RECOVERY);
196 			return (-1);
197 		}
198 		he->h_name = bp;
199 		bp += n;
200 		/* The qname can be abbreviated, but h_name is now absolute. */
201 		qname = he->h_name;
202 	}
203 	ap = hed->host_aliases;
204 	*ap = NULL;
205 	he->h_aliases = hed->host_aliases;
206 	hap = hed->h_addr_ptrs;
207 	*hap = NULL;
208 	he->h_addr_list = hed->h_addr_ptrs;
209 	haveanswer = 0;
210 	had_error = 0;
211 	_dns_ttl_ = -1;
212 	while (ancount-- > 0 && cp < eom && !had_error) {
213 		n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
214 		if ((n < 0) || !(*name_ok)(bp)) {
215 			had_error++;
216 			continue;
217 		}
218 		cp += n;			/* name */
219 		BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
220 		type = _getshort(cp);
221 		cp += INT16SZ;			/* type */
222 		class = _getshort(cp);
223 		cp += INT16SZ;			/* class */
224 		if (qtype == T_A  && type == T_A)
225 			_dns_ttl_ = _getlong(cp);
226 		cp += INT32SZ;			/* TTL */
227 		n = _getshort(cp);
228 		cp += INT16SZ;			/* len */
229 		BOUNDS_CHECK(cp, n);
230 		erdata = cp + n;
231 		if (class != C_IN) {
232 			/* XXX - debug? syslog? */
233 			cp += n;
234 			continue;		/* XXX - had_error++ ? */
235 		}
236 		if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
237 			if (ap >= &hed->host_aliases[_MAXALIASES-1])
238 				continue;
239 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
240 			if ((n < 0) || !(*name_ok)(tbuf)) {
241 				had_error++;
242 				continue;
243 			}
244 			cp += n;
245 			if (cp != erdata) {
246 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
247 				return (-1);
248 			}
249 			/* Store alias. */
250 			*ap++ = bp;
251 			n = strlen(bp) + 1;	/* for the \0 */
252 			if (n >= MAXHOSTNAMELEN) {
253 				had_error++;
254 				continue;
255 			}
256 			bp += n;
257 			/* Get canonical name. */
258 			n = strlen(tbuf) + 1;	/* for the \0 */
259 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
260 				had_error++;
261 				continue;
262 			}
263 			strcpy(bp, tbuf);
264 			he->h_name = bp;
265 			bp += n;
266 			continue;
267 		}
268 		if (qtype == T_PTR && type == T_CNAME) {
269 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
270 			if (n < 0 || !res_dnok(tbuf)) {
271 				had_error++;
272 				continue;
273 			}
274 			cp += n;
275 			if (cp != erdata) {
276 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
277 				return (-1);
278 			}
279 			/* Get canonical name. */
280 			n = strlen(tbuf) + 1;	/* for the \0 */
281 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
282 				had_error++;
283 				continue;
284 			}
285 			strcpy(bp, tbuf);
286 			tname = bp;
287 			bp += n;
288 			continue;
289 		}
290 		if (type != qtype) {
291 			if (type != T_SIG)
292 				syslog(LOG_NOTICE|LOG_AUTH,
293 	"gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"",
294 				       qname, p_class(C_IN), p_type(qtype),
295 				       p_type(type));
296 			cp += n;
297 			continue;		/* XXX - had_error++ ? */
298 		}
299 		switch (type) {
300 		case T_PTR:
301 			if (strcasecmp(tname, bp) != 0) {
302 				syslog(LOG_NOTICE|LOG_AUTH,
303 				       AskedForGot, qname, bp);
304 				cp += n;
305 				continue;	/* XXX - had_error++ ? */
306 			}
307 			n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
308 			if ((n < 0) || !res_hnok(bp)) {
309 				had_error++;
310 				break;
311 			}
312 #if MULTI_PTRS_ARE_ALIASES
313 			cp += n;
314 			if (cp != erdata) {
315 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
316 				return (-1);
317 			}
318 			if (!haveanswer)
319 				he->h_name = bp;
320 			else if (ap < &hed->host_aliases[_MAXALIASES-1])
321 				*ap++ = bp;
322 			else
323 				n = -1;
324 			if (n != -1) {
325 				n = strlen(bp) + 1;	/* for the \0 */
326 				if (n >= MAXHOSTNAMELEN) {
327 					had_error++;
328 					break;
329 				}
330 				bp += n;
331 			}
332 			break;
333 #else
334 			he->h_name = bp;
335 			if (statp->options & RES_USE_INET6) {
336 				n = strlen(bp) + 1;	/* for the \0 */
337 				if (n >= MAXHOSTNAMELEN) {
338 					had_error++;
339 					break;
340 				}
341 				bp += n;
342 				_map_v4v6_hostent(he, &bp, ep);
343 			}
344 			RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
345 			return (0);
346 #endif
347 		case T_A:
348 		case T_AAAA:
349 			if (strcasecmp(he->h_name, bp) != 0) {
350 				syslog(LOG_NOTICE|LOG_AUTH,
351 				       AskedForGot, he->h_name, bp);
352 				cp += n;
353 				continue;	/* XXX - had_error++ ? */
354 			}
355 			if (n != he->h_length) {
356 				cp += n;
357 				continue;
358 			}
359 			if (!haveanswer) {
360 				int nn;
361 
362 				he->h_name = bp;
363 				nn = strlen(bp) + 1;	/* for the \0 */
364 				bp += nn;
365 			}
366 
367 			bp += sizeof(align) - ((u_long)bp % sizeof(align));
368 
369 			if (bp + n >= ep) {
370 				dbg_printf("size (%d) too big\n", n, statp);
371 				had_error++;
372 				continue;
373 			}
374 			if (hap >= &hed->h_addr_ptrs[_MAXADDRS-1]) {
375 				if (!toobig++)
376 					dbg_printf("Too many addresses (%d)\n",
377 						_MAXADDRS, statp);
378 				cp += n;
379 				continue;
380 			}
381 			memcpy(*hap++ = bp, cp, n);
382 			bp += n;
383 			cp += n;
384 			if (cp != erdata) {
385 				RES_SET_H_ERRNO(statp, NO_RECOVERY);
386 				return (-1);
387 			}
388 			break;
389 		default:
390 			dbg_printf("Impossible condition (type=%d)\n", type,
391 			    statp);
392 			RES_SET_H_ERRNO(statp, NO_RECOVERY);
393 			return (-1);
394 			/* BIND has abort() here, too risky on bad data */
395 		}
396 		if (!had_error)
397 			haveanswer++;
398 	}
399 	if (haveanswer) {
400 		*ap = NULL;
401 		*hap = NULL;
402 # if defined(RESOLVSORT)
403 		/*
404 		 * Note: we sort even if host can take only one address
405 		 * in its return structures - should give it the "best"
406 		 * address in that case, not some random one
407 		 */
408 		if (statp->nsort && haveanswer > 1 && qtype == T_A)
409 			addrsort(hed->h_addr_ptrs, haveanswer, statp);
410 # endif /*RESOLVSORT*/
411 		if (!he->h_name) {
412 			n = strlen(qname) + 1;	/* for the \0 */
413 			if (n > ep - bp || n >= MAXHOSTNAMELEN)
414 				goto no_recovery;
415 			strcpy(bp, qname);
416 			he->h_name = bp;
417 			bp += n;
418 		}
419 		if (statp->options & RES_USE_INET6)
420 			_map_v4v6_hostent(he, &bp, ep);
421 		RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
422 		return (0);
423 	}
424  no_recovery:
425 	RES_SET_H_ERRNO(statp, NO_RECOVERY);
426 	return (-1);
427 }
428 
429 /* XXX: for async DNS resolver in ypserv */
430 struct hostent *
431 __dns_getanswer(const char *answer, int anslen, const char *qname, int qtype)
432 {
433 	struct hostent *he;
434 	struct hostent_data *hed;
435 	int error;
436 	res_state statp;
437 
438 	statp = __res_state();
439 	if ((he = __hostent_init()) == NULL ||
440 	    (hed = __hostent_data_init()) == NULL) {
441 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
442 		return (NULL);
443 	}
444 	switch (qtype) {
445 	case T_AAAA:
446 		he->h_addrtype = AF_INET6;
447 		he->h_length = NS_IN6ADDRSZ;
448 		break;
449 	case T_A:
450 	default:
451 		he->h_addrtype = AF_INET;
452 		he->h_length = NS_INADDRSZ;
453 		break;
454 	}
455 
456 	error = gethostanswer((const querybuf *)answer, anslen, qname, qtype,
457 	    he, hed, statp);
458 	return (error == 0) ? he : NULL;
459 }
460 
461 int
462 _dns_gethostbyname(void *rval, void *cb_data __unused, va_list ap)
463 {
464 	const char *name;
465 	int af;
466 	char *buffer;
467 	size_t buflen;
468 	int *errnop __unused;
469 	int *h_errnop;
470 	struct hostent *hptr, he;
471 	struct hostent_data *hed;
472 	querybuf *buf;
473 	int n, type, error;
474 	res_state statp;
475 
476 	name = va_arg(ap, const char *);
477 	af = va_arg(ap, int);
478 	hptr = va_arg(ap, struct hostent *);
479 	buffer = va_arg(ap, char *);
480 	buflen = va_arg(ap, size_t);
481 	errnop = va_arg(ap, int *);
482 	h_errnop = va_arg(ap, int *);
483 
484 	*((struct hostent **)rval) = NULL;
485 
486 	statp = __res_state();
487 	if ((hed = __hostent_data_init()) == NULL) {
488 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
489 		*h_errnop = statp->res_h_errno;
490 		return (NS_NOTFOUND);
491 	}
492 
493 	he.h_addrtype = af;
494 	switch (af) {
495 	case AF_INET:
496 		he.h_length = NS_INADDRSZ;
497 		type = T_A;
498 		break;
499 	case AF_INET6:
500 		he.h_length = NS_IN6ADDRSZ;
501 		type = T_AAAA;
502 		break;
503 	default:
504 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
505 		*h_errnop = statp->res_h_errno;
506 		errno = EAFNOSUPPORT;
507 		return (NS_UNAVAIL);
508 	}
509 
510 	if ((buf = malloc(sizeof(*buf))) == NULL) {
511 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
512 		*h_errnop = statp->res_h_errno;
513 		return (NS_NOTFOUND);
514 	}
515 	n = res_nsearch(statp, name, C_IN, type, buf->buf, sizeof(buf->buf));
516 	if (n < 0) {
517 		free(buf);
518 		dbg_printf("res_nsearch failed (%d)\n", n, statp);
519 		*h_errnop = statp->res_h_errno;
520 		return (0);
521 	} else if (n > sizeof(buf->buf)) {
522 		free(buf);
523 		dbg_printf("static buffer is too small (%d)\n", n, statp);
524 		*h_errnop = statp->res_h_errno;
525 		return (0);
526 	}
527 	error = gethostanswer(buf, n, name, type, &he, hed, statp);
528 	free(buf);
529 	if (error != 0) {
530 		*h_errnop = statp->res_h_errno;
531 		return (NS_NOTFOUND);
532 	}
533 	if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
534 		*h_errnop = statp->res_h_errno;
535 		return (NS_NOTFOUND);
536 	}
537 	*((struct hostent **)rval) = hptr;
538 	return (NS_SUCCESS);
539 }
540 
541 int
542 _dns_gethostbyaddr(void *rval, void *cb_data __unused, va_list ap)
543 {
544 	const void *addr;
545 	socklen_t len;
546 	int af;
547 	char *buffer;
548 	size_t buflen;
549 	int *errnop __unused;
550 	int *h_errnop;
551 	const u_char *uaddr;
552 	struct hostent *hptr, he;
553 	struct hostent_data *hed;
554 	int n;
555 	querybuf *buf;
556 	char qbuf[MAXDNAME+1], *qp;
557 	res_state statp;
558 #ifdef SUNSECURITY
559 	struct hostdata rhd;
560 	struct hostent *rhe;
561 	char **haddr;
562 	u_long old_options;
563 	char hname2[MAXDNAME+1], numaddr[46];
564 	int ret_h_error;
565 #endif /*SUNSECURITY*/
566 
567 	addr = va_arg(ap, const void *);
568 	len = va_arg(ap, socklen_t);
569 	af = va_arg(ap, int);
570 	hptr = va_arg(ap, struct hostent *);
571 	buffer = va_arg(ap, char *);
572 	buflen = va_arg(ap, size_t);
573 	errnop = va_arg(ap, int *);
574 	h_errnop = va_arg(ap, int *);
575 	uaddr = (const u_char *)addr;
576 
577 	*((struct hostent **)rval) = NULL;
578 
579 	statp = __res_state();
580 	if ((hed = __hostent_data_init()) == NULL) {
581 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
582 		*h_errnop = statp->res_h_errno;
583 		return (NS_NOTFOUND);
584 	}
585 
586 	switch (af) {
587 	case AF_INET:
588 		sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
589 			       (uaddr[3] & 0xff),
590 			       (uaddr[2] & 0xff),
591 			       (uaddr[1] & 0xff),
592 			       (uaddr[0] & 0xff));
593 		break;
594 	case AF_INET6:
595 		qp = qbuf;
596 		for (n = NS_IN6ADDRSZ - 1; n >= 0; n--) {
597 			qp += SPRINTF((qp, "%x.%x.",
598 				       uaddr[n] & 0xf,
599 				       (uaddr[n] >> 4) & 0xf));
600 		}
601 		strlcat(qbuf, "ip6.arpa", sizeof(qbuf));
602 		break;
603 	default:
604 		abort();
605 	}
606 	if ((buf = malloc(sizeof(*buf))) == NULL) {
607 		RES_SET_H_ERRNO(statp, NETDB_INTERNAL);
608 		*h_errnop = statp->res_h_errno;
609 		return NS_NOTFOUND;
610 	}
611 	n = res_nquery(statp, qbuf, C_IN, T_PTR, (u_char *)buf->buf,
612 	    sizeof buf->buf);
613 	if (n < 0) {
614 		free(buf);
615 		dbg_printf("res_nquery failed (%d)\n", n, statp);
616 		*h_errnop = statp->res_h_errno;
617 		return (NS_UNAVAIL);
618 	}
619 	if (n > sizeof buf->buf) {
620 		free(buf);
621 		dbg_printf("static buffer is too small (%d)\n", n, statp);
622 		*h_errnop = statp->res_h_errno;
623 		return (NS_UNAVAIL);
624 	}
625 	if (gethostanswer(buf, n, qbuf, T_PTR, &he, hed, statp) != 0) {
626 		free(buf);
627 		*h_errnop = statp->res_h_errno;
628 		return (NS_NOTFOUND);	/* h_errno was set by gethostanswer() */
629 	}
630 	free(buf);
631 #ifdef SUNSECURITY
632 	if (af == AF_INET) {
633 	    /*
634 	     * turn off search as the name should be absolute,
635 	     * 'localhost' should be matched by defnames
636 	     */
637 	    strncpy(hname2, he.h_name, MAXDNAME);
638 	    hname2[MAXDNAME] = '\0';
639 	    old_options = statp->options;
640 	    statp->options &= ~RES_DNSRCH;
641 	    statp->options |= RES_DEFNAMES;
642 	    memset(&rhd, 0, sizeof rhd);
643 	    rhe = gethostbyname_r(hname2, &rhd.host, &rhd.data,
644 	        sizeof(rhd.data), &ret_h_error);
645 	    if (rhe == NULL) {
646 		if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
647 		    strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
648 		syslog(LOG_NOTICE|LOG_AUTH,
649 		       "gethostbyaddr: No A record for %s (verifying [%s])",
650 		       hname2, numaddr);
651 		statp->options = old_options;
652 		RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
653 		*h_errnop = statp->res_h_errno;
654 		return (NS_NOTFOUND);
655 	    }
656 	    statp->options = old_options;
657 	    for (haddr = rhe->h_addr_list; *haddr; haddr++)
658 		if (!memcmp(*haddr, addr, NS_INADDRSZ))
659 			break;
660 	    if (!*haddr) {
661 		if (inet_ntop(af, addr, numaddr, sizeof(numaddr)) == NULL)
662 		    strlcpy(numaddr, "UNKNOWN", sizeof(numaddr));
663 		syslog(LOG_NOTICE|LOG_AUTH,
664 		       "gethostbyaddr: A record of %s != PTR record [%s]",
665 		       hname2, numaddr);
666 		RES_SET_H_ERRNO(statp, HOST_NOT_FOUND);
667 		*h_errnop = statp->res_h_errno;
668 		return (NS_NOTFOUND);
669 	    }
670 	}
671 #endif /*SUNSECURITY*/
672 	he.h_addrtype = af;
673 	he.h_length = len;
674 	memcpy(hed->host_addr, uaddr, len);
675 	hed->h_addr_ptrs[0] = (char *)hed->host_addr;
676 	hed->h_addr_ptrs[1] = NULL;
677 	if (af == AF_INET && (statp->options & RES_USE_INET6)) {
678 		_map_v4v6_address((char*)hed->host_addr, (char*)hed->host_addr);
679 		he.h_addrtype = AF_INET6;
680 		he.h_length = NS_IN6ADDRSZ;
681 	}
682 	RES_SET_H_ERRNO(statp, NETDB_SUCCESS);
683 	if (__copy_hostent(&he, hptr, buffer, buflen) != 0) {
684 		*h_errnop = statp->res_h_errno;
685 		return (NS_NOTFOUND);
686 	}
687 	*((struct hostent **)rval) = hptr;
688 	return (NS_SUCCESS);
689 }
690 
691 #ifdef RESOLVSORT
692 static void
693 addrsort(char **ap, int num, res_state res)
694 {
695 	int i, j;
696 	char **p;
697 	short aval[_MAXADDRS];
698 	int needsort = 0;
699 
700 	p = ap;
701 	for (i = 0; i < num; i++, p++) {
702 	    for (j = 0 ; (unsigned)j < res->nsort; j++)
703 		if (res->sort_list[j].addr.s_addr ==
704 		    (((struct in_addr *)(*p))->s_addr & res->sort_list[j].mask))
705 			break;
706 	    aval[i] = j;
707 	    if (needsort == 0 && i > 0 && j < aval[i-1])
708 		needsort = i;
709 	}
710 	if (!needsort)
711 	    return;
712 
713 	while (needsort < num) {
714 	    for (j = needsort - 1; j >= 0; j--) {
715 		if (aval[j] > aval[j+1]) {
716 		    char *hp;
717 
718 		    i = aval[j];
719 		    aval[j] = aval[j+1];
720 		    aval[j+1] = i;
721 
722 		    hp = ap[j];
723 		    ap[j] = ap[j+1];
724 		    ap[j+1] = hp;
725 
726 		} else
727 		    break;
728 	    }
729 	    needsort++;
730 	}
731 }
732 #endif
733 
734 void
735 _sethostdnsent(int stayopen)
736 {
737 	res_state statp;
738 
739 	statp = __res_state();
740 	if ((statp->options & RES_INIT) == 0 && res_ninit(statp) == -1)
741 		return;
742 	if (stayopen)
743 		statp->options |= RES_STAYOPEN | RES_USEVC;
744 }
745 
746 void
747 _endhostdnsent(void)
748 {
749 	res_state statp;
750 
751 	statp = __res_state();
752 	statp->options &= ~(RES_STAYOPEN | RES_USEVC);
753 	res_nclose(statp);
754 }
755