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. 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 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
36 *
37 * Permission to use, copy, modify, and distribute this software for any
38 * purpose with or without fee is hereby granted, provided that the above
39 * copyright notice and this permission notice appear in all copies, and that
40 * the name of Digital Equipment Corporation not be used in advertising or
41 * publicity pertaining to distribution of the document or software without
42 * specific, written prior permission.
43 *
44 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
45 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
46 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
47 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
48 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
49 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
50 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
51 * SOFTWARE.
52 * -
53 * --Copyright--
54 */
55
56/*
57 * Portions copyright (c) 1999, 2000
58 * Intel Corporation.
59 * All rights reserved.
60 *
61 * Redistribution and use in source and binary forms, with or without
62 * modification, are permitted provided that the following conditions
63 * are met:
64 *
65 * 1. Redistributions of source code must retain the above copyright
66 *    notice, this list of conditions and the following disclaimer.
67 *
68 * 2. Redistributions in binary form must reproduce the above copyright
69 *    notice, this list of conditions and the following disclaimer in the
70 *    documentation and/or other materials provided with the distribution.
71 *
72 * 3. All advertising materials mentioning features or use of this software
73 *    must display the following acknowledgement:
74 *
75 *    This product includes software developed by Intel Corporation and
76 *    its contributors.
77 *
78 * 4. Neither the name of Intel Corporation or its contributors may be
79 *    used to endorse or promote products derived from this software
80 *    without specific prior written permission.
81 *
82 * THIS SOFTWARE IS PROVIDED BY INTEL CORPORATION AND CONTRIBUTORS ``AS IS''
83 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
84 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
85 * ARE DISCLAIMED.  IN NO EVENT SHALL INTEL CORPORATION OR CONTRIBUTORS BE
86 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
87 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
88 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
89 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
90 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
91 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
92 * THE POSSIBILITY OF SUCH DAMAGE.
93 *
94 */
95
96#if defined(LIBC_SCCS) && !defined(lint)
97static char sccsid[] = "@(#)gethostnamadr.c	8.1 (Berkeley) 6/4/93";
98static char fromrcsid[] = "From: Id: gethnamaddr.c,v 8.23 1998/04/07 04:59:46 vixie Exp $";
99static char rcsid[] = "$Id: gethostbydns.c,v 1.1.1.1 2003/11/19 01:51:27 kyu3 Exp $";
100#endif /* LIBC_SCCS and not lint */
101
102#include <sys/types.h>
103#include <sys/param.h>
104#include <sys/socket.h>
105#include <netinet/in.h>
106#include <arpa/inet.h>
107#include <arpa/nameser.h>
108
109#include <stdio.h>
110#include <unistd.h>
111#include <string.h>
112#include <netdb.h>
113#include <resolv.h>
114#include <ctype.h>
115#include <errno.h>
116#ifdef _ORG_FREEBSD_
117#include <syslog.h>
118#else
119#include <stdlib.h>
120u_int32_t _getlong(const u_char *src);
121u_int16_t _getshort(const u_char *src);
122#endif
123
124#include "res_config.h"
125#include "Socklib_internals.h"
126
127#define SPRINTF(x) ((size_t)sprintf x)
128
129#define	MAXALIASES	35
130#define	MAXADDRS	35
131
132static const char AskedForGot[] =
133		"gethostby*.gethostanswer: asked for \"%s\", got \"%s\"";
134
135static char *h_addr_ptrs[MAXADDRS + 1];
136
137static struct hostent host;
138static char *host_aliases[MAXALIASES];
139static char hostbuf[8*1024];
140static u_char host_addr[16];	/* IPv4 or IPv6 */
141
142#ifdef RESOLVSORT
143static void addrsort(char **, int);
144#endif
145
146#if PACKETSZ > 1024
147#define	MAXPACKET	PACKETSZ
148#else
149#define	MAXPACKET	1024
150#endif
151
152typedef union {
153    HEADER hdr;
154    u_char buf[MAXPACKET];
155} querybuf;
156
157typedef union {
158    int32_t al;
159    char ac;
160} align;
161
162extern int h_errno;
163int _dns_ttl_;
164
165#ifdef DEBUG_RES
166static void
167dprintf(char *msg, int num)
168{
169	if (_res.options & RES_DEBUG) {
170		int save = errno;
171
172		printf(msg, num);
173		errno = save;
174	}
175}
176#else
177# define dprintf(msg, num) /*nada*/
178#endif
179
180#define BOUNDED_INCR(x) \
181	do { \
182		cp += x; \
183		if (cp > eom) { \
184			h_errno = NO_RECOVERY; \
185			return (NULL); \
186		} \
187	} while (0)
188
189#define BOUNDS_CHECK(ptr, count) \
190	do { \
191		if ((ptr) + (count) > eom) { \
192			h_errno = NO_RECOVERY; \
193			return (NULL); \
194		} \
195	} while (0)
196
197static struct hostent *
198gethostanswer(const querybuf *answer, int anslen, const char *qname, int qtype)
199{
200	register const HEADER *hp;
201	register const u_char *cp;
202	register int n;
203	const u_char *eom, *erdata;
204	char *bp, **ap, **hap;
205	int type, class, buflen, ancount, qdcount;
206	int haveanswer, had_error;
207	int toobig = 0;
208	char tbuf[MAXDNAME];
209	const char *tname;
210	int (*name_ok)(const char *);
211
212	tname = qname;
213	host.h_name = NULL;
214	eom = answer->buf + anslen;
215	switch (qtype) {
216	case T_A:
217	case T_AAAA:
218		name_ok = res_hnok;
219		break;
220	case T_PTR:
221		name_ok = res_dnok;
222		break;
223	default:
224		h_errno = NO_RECOVERY;
225		return (NULL);	/* XXX should be abort(); */
226	}
227	/*
228	 * find first satisfactory answer
229	 */
230	hp = &answer->hdr;
231	ancount = ntohs(hp->ancount);
232	qdcount = ntohs(hp->qdcount);
233	bp = hostbuf;
234	buflen = sizeof hostbuf;
235	cp = answer->buf;
236	BOUNDED_INCR(HFIXEDSZ);
237	if (qdcount != 1) {
238		h_errno = NO_RECOVERY;
239		return (NULL);
240	}
241	n = dn_expand(answer->buf, eom, cp, bp, buflen);
242	if ((n < 0) || !(*name_ok)(bp)) {
243		h_errno = NO_RECOVERY;
244		return (NULL);
245	}
246	BOUNDED_INCR(n + QFIXEDSZ);
247	if (qtype == T_A || qtype == T_AAAA) {
248		/* res_send() has already verified that the query name is the
249		 * same as the one we sent; this just gets the expanded name
250		 * (i.e., with the succeeding search-domain tacked on).
251		 */
252		n = (int)strlen(bp) + 1;		/* for the \0 */
253		if (n >= MAXHOSTNAMELEN) {
254			h_errno = NO_RECOVERY;
255			return (NULL);
256		}
257		host.h_name = bp;
258		bp += n;
259		buflen -= n;
260		/* The qname can be abbreviated, but h_name is now absolute. */
261		qname = host.h_name;
262	}
263	ap = host_aliases;
264	*ap = NULL;
265	host.h_aliases = host_aliases;
266	hap = h_addr_ptrs;
267	*hap = NULL;
268	host.h_addr_list = h_addr_ptrs;
269	haveanswer = 0;
270	had_error = 0;
271	_dns_ttl_ = -1;
272	while (ancount-- > 0 && cp < eom && !had_error) {
273		n = dn_expand(answer->buf, eom, cp, bp, buflen);
274		if ((n < 0) || !(*name_ok)(bp)) {
275			had_error++;
276			continue;
277		}
278		cp += n;			/* name */
279		BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
280		type = _getshort(cp);
281 		cp += INT16SZ;			/* type */
282		class = _getshort(cp);
283 		cp += INT16SZ;			/* class */
284		if (qtype == T_A  && type == T_A)
285			_dns_ttl_ = _getlong(cp);
286		cp += INT32SZ;			/* TTL */
287		n = _getshort(cp);
288		cp += INT16SZ;			/* len */
289		BOUNDS_CHECK(cp, n);
290		erdata = cp + n;
291		if (class != C_IN) {
292			/* XXX - debug? syslog? */
293			cp += n;
294			continue;		/* XXX - had_error++ ? */
295		}
296		if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
297			if (ap >= &host_aliases[MAXALIASES-1])
298				continue;
299			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
300			if ((n < 0) || !(*name_ok)(tbuf)) {
301				had_error++;
302				continue;
303			}
304			cp += n;
305			if (cp != erdata) {
306				h_errno = NO_RECOVERY;
307				return (NULL);
308			}
309			/* Store alias. */
310			*ap++ = bp;
311			n = (int)strlen(bp) + 1;	/* for the \0 */
312			if (n >= MAXHOSTNAMELEN) {
313				had_error++;
314				continue;
315			}
316			bp += n;
317			buflen -= n;
318			/* Get canonical name. */
319			n = (int)strlen(tbuf) + 1;	/* for the \0 */
320			if (n > buflen || n >= MAXHOSTNAMELEN) {
321				had_error++;
322				continue;
323			}
324			strcpy(bp, tbuf);
325			host.h_name = bp;
326			bp += n;
327			buflen -= n;
328			continue;
329		}
330		if (qtype == T_PTR && type == T_CNAME) {
331			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
332			if (n < 0 || !res_dnok(tbuf)) {
333				had_error++;
334				continue;
335			}
336			cp += n;
337			if (cp != erdata) {
338				h_errno = NO_RECOVERY;
339				return (NULL);
340			}
341			/* Get canonical name. */
342			n = (int)strlen(tbuf) + 1;	/* for the \0 */
343			if (n > buflen || n >= MAXHOSTNAMELEN) {
344				had_error++;
345				continue;
346			}
347			strcpy(bp, tbuf);
348			tname = bp;
349			bp += n;
350			buflen -= n;
351			continue;
352		}
353		if (type != qtype) {
354#ifdef _ORG_FREEBSD_
355			syslog(LOG_NOTICE|LOG_AUTH,
356	"gethostby*.gethostanswer: asked for \"%s %s %s\", got type \"%s\"",
357			       qname, p_class(C_IN), p_type(qtype),
358			       p_type(type));
359#endif
360			cp += n;
361			continue;		/* XXX - had_error++ ? */
362		}
363		switch (type) {
364		case T_PTR:
365			if (strcasecmp(tname, bp) != 0) {
366#ifdef _ORG_FREEBSD_
367				syslog(LOG_NOTICE|LOG_AUTH,
368				       AskedForGot, qname, bp);
369#endif
370				cp += n;
371				continue;	/* XXX - had_error++ ? */
372			}
373			n = dn_expand(answer->buf, eom, cp, bp, buflen);
374			if ((n < 0) || !res_hnok(bp)) {
375				had_error++;
376				break;
377			}
378#if MULTI_PTRS_ARE_ALIASES
379			cp += n;
380			if (cp != erdata) {
381				h_errno = NO_RECOVERY;
382				return (NULL);
383			}
384			if (!haveanswer)
385				host.h_name = bp;
386			else if (ap < &host_aliases[MAXALIASES-1])
387				*ap++ = bp;
388			else
389				n = -1;
390			if (n != -1) {
391				n = (int)strlen(bp) + 1;	/* for the \0 */
392				if (n >= MAXHOSTNAMELEN) {
393					had_error++;
394					break;
395				}
396				bp += n;
397				buflen -= n;
398			}
399			break;
400#else
401			host.h_name = bp;
402			if (_res.options & RES_USE_INET6) {
403				n = strlen(bp) + 1;	/* for the \0 */
404				if (n >= MAXHOSTNAMELEN) {
405					had_error++;
406					break;
407				}
408				bp += n;
409				buflen -= n;
410				_map_v4v6_hostent(&host, &bp, &buflen);
411			}
412			h_errno = NETDB_SUCCESS;
413			return (&host);
414#endif
415		case T_A:
416		case T_AAAA:
417			if (strcasecmp(host.h_name, bp) != 0) {
418#ifdef _ORG_FREEBSD_
419				syslog(LOG_NOTICE|LOG_AUTH,
420				       AskedForGot, host.h_name, bp);
421#endif
422				cp += n;
423				continue;	/* XXX - had_error++ ? */
424			}
425			if (n != host.h_length) {
426				cp += n;
427				continue;
428			}
429			if (!haveanswer) {
430				register int nn;
431
432				host.h_name = bp;
433				nn = (int)strlen(bp) + 1;	/* for the \0 */
434				bp += nn;
435				buflen -= nn;
436			}
437
438			bp += sizeof(align) - ((size_t)bp % sizeof(align));
439
440			if (bp + n >= &hostbuf[sizeof hostbuf]) {
441				dprintf("size (%d) too big\n", n);
442				had_error++;
443				continue;
444			}
445			if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
446				if (!toobig++)
447					dprintf("Too many addresses (%d)\n",
448						MAXADDRS);
449				cp += n;
450				continue;
451			}
452      *hap++ = bp;
453			bcopy(cp, bp, n);
454			bp += n;
455			buflen -= n;
456			cp += n;
457			if (cp != erdata) {
458				h_errno = NO_RECOVERY;
459				return (NULL);
460			}
461			break;
462		default:
463			dprintf("Impossible condition (type=%d)\n", type);
464			h_errno = NO_RECOVERY;
465			return (NULL);
466			/* BIND has abort() here, too risky on bad data */
467		}
468		if (!had_error)
469			haveanswer++;
470	}
471	if (haveanswer) {
472		*ap = NULL;
473		*hap = NULL;
474# if defined(RESOLVSORT)
475		/*
476		 * Note: we sort even if host can take only one address
477		 * in its return structures - should give it the "best"
478		 * address in that case, not some random one
479		 */
480		if (_res.nsort && haveanswer > 1 && qtype == T_A)
481			addrsort(h_addr_ptrs, haveanswer);
482# endif /*RESOLVSORT*/
483		if (!host.h_name) {
484			n = (int)strlen(qname) + 1;	/* for the \0 */
485			if (n > buflen || n >= MAXHOSTNAMELEN)
486				goto no_recovery;
487			strcpy(bp, qname);
488			host.h_name = bp;
489			bp += n;
490			buflen -= n;
491		}
492		if (_res.options & RES_USE_INET6)
493			_map_v4v6_hostent(&host, &bp, &buflen);
494		h_errno = NETDB_SUCCESS;
495		return (&host);
496	}
497 no_recovery:
498	h_errno = NO_RECOVERY;
499	return (NULL);
500}
501
502struct hostent *
503__dns_getanswer(const char *answer, int anslen, const char *qname, int qtype)
504{
505	switch(qtype) {
506	case T_AAAA:
507		host.h_addrtype = AF_INET6;
508		host.h_length = IN6ADDRSZ;
509		break;
510	case T_A:
511	default:
512		host.h_addrtype = AF_INET;
513		host.h_length = INADDRSZ;
514		break;
515	}
516
517	return(gethostanswer((const querybuf *)answer, anslen, qname, qtype));
518}
519
520struct hostent *
521_gethostbydnsname(const char *name, int af)
522{
523	querybuf buf;
524	register const char *cp;
525	char *bp;
526	int n, size, type, len;
527
528	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
529		h_errno = NETDB_INTERNAL;
530		return (NULL);
531	}
532
533	switch (af) {
534	case AF_INET:
535		size = INADDRSZ;
536		type = T_A;
537		break;
538	case AF_INET6:
539		size = IN6ADDRSZ;
540		type = T_AAAA;
541		break;
542	default:
543		h_errno = NETDB_INTERNAL;
544		errno = EAFNOSUPPORT;
545		return (NULL);
546	}
547
548	host.h_addrtype = af;
549	host.h_length = size;
550
551	/*
552	 * if there aren't any dots, it could be a user-level alias.
553	 * this is also done in res_query() since we are not the only
554	 * function that looks up host names.
555	 */
556	if (!strchr(name, '.') && ( NULL != (cp = __hostalias(name))))
557		name = cp;
558
559	/*
560	 * disallow names consisting only of digits/dots, unless
561	 * they end in a dot.
562	 */
563	if (isdigit(name[0]))
564		for (cp = name;; ++cp) {
565			if (!*cp) {
566				if (*--cp == '.')
567					break;
568				/*
569				 * All-numeric, no dot at the end.
570				 * Fake up a hostent as if we'd actually
571				 * done a lookup.
572				 */
573				if (inet_pton(af, name, host_addr) <= 0) {
574					h_errno = HOST_NOT_FOUND;
575					return (NULL);
576				}
577				strncpy(hostbuf, name, MAXDNAME);
578				hostbuf[MAXDNAME] = '\0';
579				bp = hostbuf + MAXDNAME;
580				len = sizeof hostbuf - MAXDNAME;
581				host.h_name = hostbuf;
582				host.h_aliases = host_aliases;
583				host_aliases[0] = NULL;
584				h_addr_ptrs[0] = (char *)host_addr;
585				h_addr_ptrs[1] = NULL;
586				host.h_addr_list = h_addr_ptrs;
587				if (_res.options & RES_USE_INET6)
588					_map_v4v6_hostent(&host, &bp, &len);
589				h_errno = NETDB_SUCCESS;
590				return (&host);
591			}
592			if (!isdigit(*cp) && *cp != '.')
593				break;
594		}
595	if ((isxdigit(name[0]) && strchr(name, ':') != NULL) ||
596	    name[0] == ':')
597		for (cp = name;; ++cp) {
598			if (!*cp) {
599				if (*--cp == '.')
600					break;
601				/*
602				 * All-IPv6-legal, no dot at the end.
603				 * Fake up a hostent as if we'd actually
604				 * done a lookup.
605				 */
606				if (inet_pton(af, name, host_addr) <= 0) {
607					h_errno = HOST_NOT_FOUND;
608					return (NULL);
609				}
610				strncpy(hostbuf, name, MAXDNAME);
611				hostbuf[MAXDNAME] = '\0';
612				bp = hostbuf + MAXDNAME;
613				len = sizeof hostbuf - MAXDNAME;
614				host.h_name = hostbuf;
615				host.h_aliases = host_aliases;
616				host_aliases[0] = NULL;
617				h_addr_ptrs[0] = (char *)host_addr;
618				h_addr_ptrs[1] = NULL;
619				host.h_addr_list = h_addr_ptrs;
620				h_errno = NETDB_SUCCESS;
621				return (&host);
622			}
623			if (!isxdigit(*cp) && *cp != ':' && *cp != '.')
624				break;
625		}
626
627	if ((n = res_search(name, C_IN, type, buf.buf, sizeof(buf))) < 0) {
628		dprintf("res_search failed (%d)\n", n);
629		return (NULL);
630	}
631	return (gethostanswer(&buf, n, name, type));
632}
633
634struct hostent *
635_gethostbydnsaddr(const char *addr, int len, int af)
636{
637	const u_char *uaddr = (const u_char *)addr;
638	static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
639	static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
640	int n, size;
641	querybuf buf;
642	register struct hostent *hp;
643	char qbuf[MAXDNAME+1], *qp;
644#ifdef SUNSECURITY
645	register struct hostent *rhp;
646	char **haddr;
647	u_long old_options;
648	char hname2[MAXDNAME+1];
649#endif /*SUNSECURITY*/
650
651	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
652		h_errno = NETDB_INTERNAL;
653		return (NULL);
654	}
655	if (af == AF_INET6 && len == IN6ADDRSZ &&
656	    (!bcmp(uaddr, mapped, sizeof mapped) ||
657	     !bcmp(uaddr, tunnelled, sizeof tunnelled))) {
658		/* Unmap. */
659		addr += sizeof mapped;
660		uaddr += sizeof mapped;
661		af = AF_INET;
662		len = INADDRSZ;
663	}
664	switch (af) {
665	case AF_INET:
666		size = INADDRSZ;
667		break;
668	case AF_INET6:
669		size = IN6ADDRSZ;
670		break;
671	default:
672		errno = EAFNOSUPPORT;
673		h_errno = NETDB_INTERNAL;
674		return (NULL);
675	}
676	if (size != len) {
677		errno = EINVAL;
678		h_errno = NETDB_INTERNAL;
679		return (NULL);
680	}
681	switch (af) {
682	case AF_INET:
683		(void) sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
684			       (uaddr[3] & 0xff),
685			       (uaddr[2] & 0xff),
686			       (uaddr[1] & 0xff),
687			       (uaddr[0] & 0xff));
688		break;
689	case AF_INET6:
690		qp = qbuf;
691		for (n = IN6ADDRSZ - 1; n >= 0; n--) {
692			qp += SPRINTF((qp, "%x.%x.",
693				       uaddr[n] & 0xf,
694				       (uaddr[n] >> 4) & 0xf));
695		}
696		strcpy(qp, "ip6.int");
697		break;
698	default:
699		abort();
700	}
701	n = res_query(qbuf, C_IN, T_PTR, (u_char *)buf.buf, sizeof buf.buf);
702	if (n < 0) {
703		dprintf("res_query failed (%d)\n", n);
704		return (NULL);
705	}
706	if ( NULL == (hp = gethostanswer(&buf, n, qbuf, T_PTR)))
707		return (NULL);	/* h_errno was set by gethostanswer() */
708#ifdef SUNSECURITY
709	if (af == AF_INET) {
710	    /*
711	     * turn off search as the name should be absolute,
712	     * 'localhost' should be matched by defnames
713	     */
714	    strncpy(hname2, hp->h_name, MAXDNAME);
715	    hname2[MAXDNAME] = '\0';
716	    old_options = _res.options;
717	    _res.options &= ~RES_DNSRCH;
718	    _res.options |= RES_DEFNAMES;
719	    if (!(rhp = gethostbyname(hname2))) {
720#ifdef _ORG_FREEBSD_
721		syslog(LOG_NOTICE|LOG_AUTH,
722		       "gethostbyaddr: No A record for %s (verifying [%s])",
723		       hname2, inet_ntoa(*((struct in_addr *)addr)));
724#endif
725		_res.options = old_options;
726		h_errno = HOST_NOT_FOUND;
727		return (NULL);
728	    }
729	    _res.options = old_options;
730	    for (haddr = rhp->h_addr_list; *haddr; haddr++)
731		if (!memcmp(*haddr, addr, INADDRSZ))
732			break;
733	    if (!*haddr) {
734#ifdef _ORG_FREEBSD_
735		syslog(LOG_NOTICE|LOG_AUTH,
736		       "gethostbyaddr: A record of %s != PTR record [%s]",
737		       hname2, inet_ntoa(*((struct in_addr *)addr)));
738#endif
739		h_errno = HOST_NOT_FOUND;
740		return (NULL);
741	    }
742	}
743#endif /*SUNSECURITY*/
744	hp->h_addrtype = af;
745	hp->h_length = len;
746	bcopy(addr, host_addr, len);
747	h_addr_ptrs[0] = (char *)host_addr;
748	h_addr_ptrs[1] = NULL;
749	if (af == AF_INET && (_res.options & RES_USE_INET6)) {
750		_map_v4v6_address((char*)host_addr, (char*)host_addr);
751		hp->h_addrtype = AF_INET6;
752		hp->h_length = IN6ADDRSZ;
753	}
754	h_errno = NETDB_SUCCESS;
755	return (hp);
756}
757
758#ifdef RESOLVSORT
759static void
760addrsort(char **ap, int num)
761{
762	short i, j;
763	char **p;
764	short aval[MAXADDRS];
765	short needsort = 0;
766
767	p = ap;
768	for (i = 0; i < num; i++, p++) {
769	    for (j = 0 ; (unsigned)j < _res.nsort; j++)
770		if (_res.sort_list[j].addr.s_addr ==
771		    (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
772			break;
773	    aval[i] = j;
774	    if (needsort == 0 && i > 0 && j < aval[i-1])
775		needsort = i;
776	}
777	if (!needsort)
778	    return;
779
780	while (needsort < num) {
781	    for (j = needsort - 1; j >= 0; j--) {
782		if (aval[j] > aval[j+1]) {
783		    char *hp;
784
785		    i = aval[j];
786		    aval[j] = aval[j+1];
787		    aval[j+1] = i;
788
789		    hp = ap[j];
790		    ap[j] = ap[j+1];
791		    ap[j+1] = hp;
792
793		} else
794		    break;
795	    }
796	    needsort++;
797	}
798}
799#endif
800void
801_sethostdnsent(int stayopen)
802{
803	if ((_res.options & RES_INIT) == 0 && res_init() == -1)
804		return;
805	if (stayopen)
806		_res.options |= RES_STAYOPEN | RES_USEVC;
807}
808
809void
810_endhostdnsent()
811{
812	_res.options &= ~(RES_STAYOPEN | RES_USEVC);
813	res_close();
814}
815