xref: /netbsd-src/lib/libc/net/gethnamaddr.c (revision d20841bb642898112fe68f0ad3f7b26dddf56f07)
1 /*	$NetBSD: gethnamaddr.c,v 1.58 2003/10/11 03:35:42 enami Exp $	*/
2 
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 #include <sys/cdefs.h>
55 #if defined(LIBC_SCCS) && !defined(lint)
56 #if 0
57 static char sccsid[] = "@(#)gethostnamadr.c	8.1 (Berkeley) 6/4/93";
58 static char rcsid[] = "Id: gethnamaddr.c,v 8.21 1997/06/01 20:34:37 vixie Exp ";
59 #else
60 __RCSID("$NetBSD: gethnamaddr.c,v 1.58 2003/10/11 03:35:42 enami Exp $");
61 #endif
62 #endif /* LIBC_SCCS and not lint */
63 
64 #if defined(_LIBC)
65 #include "namespace.h"
66 #endif
67 #include <sys/param.h>
68 #include <sys/socket.h>
69 #include <netinet/in.h>
70 #include <arpa/inet.h>
71 #include <arpa/nameser.h>
72 
73 #include <assert.h>
74 #include <ctype.h>
75 #include <errno.h>
76 #include <netdb.h>
77 #include <resolv.h>
78 #include <stdarg.h>
79 #include <stdio.h>
80 #include <syslog.h>
81 
82 #ifndef LOG_AUTH
83 # define LOG_AUTH 0
84 #endif
85 
86 #define MULTI_PTRS_ARE_ALIASES 1	/* XXX - experimental */
87 
88 #include <nsswitch.h>
89 #include <stdlib.h>
90 #include <string.h>
91 
92 #ifdef YP
93 #include <rpc/rpc.h>
94 #include <rpcsvc/yp_prot.h>
95 #include <rpcsvc/ypclnt.h>
96 #endif
97 
98 #if defined(_LIBC) && defined(__weak_alias)
99 __weak_alias(gethostbyaddr,_gethostbyaddr)
100 __weak_alias(gethostbyname,_gethostbyname)
101 #endif
102 
103 #define	MAXALIASES	35
104 #define	MAXADDRS	35
105 
106 static const char AskedForGot[] =
107 			  "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
108 
109 static char *h_addr_ptrs[MAXADDRS + 1];
110 
111 #ifdef YP
112 static char *__ypdomain;
113 #endif
114 
115 static struct hostent host;
116 static char *host_aliases[MAXALIASES];
117 static char hostbuf[8*1024];
118 static u_int32_t host_addr[16 / sizeof(u_int32_t)];	/* IPv4 or IPv6 */
119 static FILE *hostf = NULL;
120 static int stayopen = 0;
121 
122 #define	MAXPACKET	(64*1024)
123 
124 typedef union {
125     HEADER hdr;
126     u_char buf[MAXPACKET];
127 } querybuf;
128 
129 typedef union {
130     int32_t al;
131     char ac;
132 } align;
133 
134 #ifdef DEBUG
135 static void dprintf __P((char *, ...))
136 	__attribute__((__format__(__printf__, 1, 2)));
137 #endif
138 static struct hostent *getanswer __P((const querybuf *, int,
139     const char *, int));
140 static void map_v4v6_address __P((const char *, char *));
141 static void map_v4v6_hostent __P((struct hostent *, char **, char *));
142 #ifdef RESOLVSORT
143 static void addrsort __P((char **, int));
144 #endif
145 
146 void _sethtent __P((int));
147 void _endhtent __P((void));
148 struct hostent *_gethtent __P((void));
149 struct hostent *_gethtbyname2 __P((const char *, int));
150 void ht_sethostent __P((int));
151 void ht_endhostent __P((void));
152 struct hostent *ht_gethostbyname __P((char *));
153 struct hostent *ht_gethostbyaddr __P((const char *, int, int ));
154 void dns_service __P((void));
155 #undef dn_skipname
156 int dn_skipname __P((const u_char *, const u_char *));
157 int _gethtbyaddr __P((void *, void *, va_list));
158 int _gethtbyname __P((void *, void *, va_list));
159 int _dns_gethtbyaddr __P((void *, void *, va_list));
160 int _dns_gethtbyname __P((void *, void *, va_list));
161 #ifdef YP
162 struct hostent *_yphostent __P((char *, int));
163 int _yp_gethtbyaddr __P((void *, void *, va_list));
164 int _yp_gethtbyname __P((void *, void *, va_list));
165 #endif
166 
167 static const ns_src default_dns_files[] = {
168 	{ NSSRC_FILES, 	NS_SUCCESS },
169 	{ NSSRC_DNS, 	NS_SUCCESS },
170 	{ 0 }
171 };
172 
173 
174 #ifdef DEBUG
175 static void
176 dprintf(char *msg, ...)
177 {
178 	_DIAGASSERT(msg != NULL);
179 
180 	if (_res.options & RES_DEBUG) {
181 		int save = errno;
182 		va_list ap;
183 
184 		va_start (ap, msg);
185 		vprintf(msg, ap);
186 		va_end (ap);
187 
188 		errno = save;
189 	}
190 }
191 #else
192 # define dprintf(msg, num) /*nada*/
193 #endif
194 
195 #define BOUNDED_INCR(x) \
196 	do { \
197 		cp += (x); \
198 		if (cp > eom) { \
199 			h_errno = NO_RECOVERY; \
200 			return (NULL); \
201 		} \
202 	} while (/*CONSTCOND*/0)
203 
204 #define BOUNDS_CHECK(ptr, count) \
205 	do { \
206 		if ((ptr) + (count) > eom) { \
207 			h_errno = NO_RECOVERY; \
208 			return (NULL); \
209 		} \
210 	} while (/*CONSTCOND*/0)
211 
212 static struct hostent *
213 getanswer(answer, anslen, qname, qtype)
214 	const querybuf *answer;
215 	int anslen;
216 	const char *qname;
217 	int qtype;
218 {
219 	const HEADER *hp;
220 	const u_char *cp;
221 	int n;
222 	const u_char *eom, *erdata;
223 	char *bp, **ap, **hap, *ep;
224 	int type, class, ancount, qdcount;
225 	int haveanswer, had_error;
226 	int toobig = 0;
227 	char tbuf[MAXDNAME];
228 	const char *tname;
229 	int (*name_ok) __P((const char *));
230 
231 	_DIAGASSERT(answer != NULL);
232 	_DIAGASSERT(qname != NULL);
233 
234 	tname = qname;
235 	host.h_name = NULL;
236 	eom = answer->buf + anslen;
237 	switch (qtype) {
238 	case T_A:
239 	case T_AAAA:
240 		name_ok = res_hnok;
241 		break;
242 	case T_PTR:
243 		name_ok = res_dnok;
244 		break;
245 	default:
246 		return (NULL);	/* XXX should be abort(); */
247 	}
248 	/*
249 	 * find first satisfactory answer
250 	 */
251 	hp = &answer->hdr;
252 	ancount = ntohs(hp->ancount);
253 	qdcount = ntohs(hp->qdcount);
254 	bp = hostbuf;
255 	ep = hostbuf + sizeof hostbuf;
256 	cp = answer->buf;
257 	BOUNDED_INCR(HFIXEDSZ);
258 	if (qdcount != 1) {
259 		h_errno = NO_RECOVERY;
260 		return (NULL);
261 	}
262 	n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
263 	if ((n < 0) || !(*name_ok)(bp)) {
264 		h_errno = NO_RECOVERY;
265 		return (NULL);
266 	}
267 	BOUNDED_INCR(n + QFIXEDSZ);
268 	if (qtype == T_A || qtype == T_AAAA) {
269 		/* res_send() has already verified that the query name is the
270 		 * same as the one we sent; this just gets the expanded name
271 		 * (i.e., with the succeeding search-domain tacked on).
272 		 */
273 		n = strlen(bp) + 1;		/* for the \0 */
274 		if (n >= MAXHOSTNAMELEN) {
275 			h_errno = NO_RECOVERY;
276 			return (NULL);
277 		}
278 		host.h_name = bp;
279 		bp += n;
280 		/* The qname can be abbreviated, but h_name is now absolute. */
281 		qname = host.h_name;
282 	}
283 	ap = host_aliases;
284 	*ap = NULL;
285 	host.h_aliases = host_aliases;
286 	hap = h_addr_ptrs;
287 	*hap = NULL;
288 	host.h_addr_list = h_addr_ptrs;
289 	haveanswer = 0;
290 	had_error = 0;
291 	while (ancount-- > 0 && cp < eom && !had_error) {
292 		n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
293 		if ((n < 0) || !(*name_ok)(bp)) {
294 			had_error++;
295 			continue;
296 		}
297 		cp += n;			/* name */
298 		BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
299 		type = _getshort(cp);
300  		cp += INT16SZ;			/* type */
301 		class = _getshort(cp);
302  		cp += INT16SZ + INT32SZ;	/* class, TTL */
303 		n = _getshort(cp);
304 		cp += INT16SZ;			/* len */
305 		BOUNDS_CHECK(cp, n);
306 		erdata = cp + n;
307 		if (class != C_IN) {
308 			/* XXX - debug? syslog? */
309 			cp += n;
310 			continue;		/* XXX - had_error++ ? */
311 		}
312 		if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
313 			if (ap >= &host_aliases[MAXALIASES-1])
314 				continue;
315 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
316 			if ((n < 0) || !(*name_ok)(tbuf)) {
317 				had_error++;
318 				continue;
319 			}
320 			cp += n;
321 			if (cp != erdata) {
322 				h_errno = NO_RECOVERY;
323 				return (NULL);
324 			}
325 			/* Store alias. */
326 			*ap++ = bp;
327 			n = strlen(bp) + 1;	/* for the \0 */
328 			if (n >= MAXHOSTNAMELEN) {
329 				had_error++;
330 				continue;
331 			}
332 			bp += n;
333 			/* Get canonical name. */
334 			n = strlen(tbuf) + 1;	/* for the \0 */
335 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
336 				had_error++;
337 				continue;
338 			}
339 			strlcpy(bp, tbuf, (size_t)(ep - bp));
340 			host.h_name = bp;
341 			bp += n;
342 			continue;
343 		}
344 		if (qtype == T_PTR && type == T_CNAME) {
345 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
346 			if (n < 0 || !res_dnok(tbuf)) {
347 				had_error++;
348 				continue;
349 			}
350 			cp += n;
351 			if (cp != erdata) {
352 				h_errno = NO_RECOVERY;
353 				return (NULL);
354 			}
355 			/* Get canonical name. */
356 			n = strlen(tbuf) + 1;	/* for the \0 */
357 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
358 				had_error++;
359 				continue;
360 			}
361 			strlcpy(bp, tbuf, (size_t)(ep - bp));
362 			tname = bp;
363 			bp += n;
364 			continue;
365 		}
366 		if (type != qtype) {
367 			if (type != T_KEY && type != T_SIG)
368 				syslog(LOG_NOTICE|LOG_AUTH,
369 	       "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
370 				       qname, p_class(C_IN), p_type(qtype),
371 				       p_type(type));
372 			cp += n;
373 			continue;		/* XXX - had_error++ ? */
374 		}
375 		switch (type) {
376 		case T_PTR:
377 			if (strcasecmp(tname, bp) != 0) {
378 				syslog(LOG_NOTICE|LOG_AUTH,
379 				       AskedForGot, qname, bp);
380 				cp += n;
381 				continue;	/* XXX - had_error++ ? */
382 			}
383 			n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
384 			if ((n < 0) || !res_hnok(bp)) {
385 				had_error++;
386 				break;
387 			}
388 #if MULTI_PTRS_ARE_ALIASES
389 			cp += n;
390 			if (cp != erdata) {
391 				h_errno = NO_RECOVERY;
392 				return (NULL);
393 			}
394 			if (!haveanswer)
395 				host.h_name = bp;
396 			else if (ap < &host_aliases[MAXALIASES-1])
397 				*ap++ = bp;
398 			else
399 				n = -1;
400 			if (n != -1) {
401 				n = strlen(bp) + 1;	/* for the \0 */
402 				if (n >= MAXHOSTNAMELEN) {
403 					had_error++;
404 					break;
405 				}
406 				bp += n;
407 			}
408 			break;
409 #else
410 			host.h_name = bp;
411 			if (_res.options & RES_USE_INET6) {
412 				n = strlen(bp) + 1;	/* for the \0 */
413 				if (n >= MAXHOSTNAMELEN) {
414 					had_error++;
415 					break;
416 				}
417 				bp += n;
418 				map_v4v6_hostent(&host, &bp, ep);
419 			}
420 			h_errno = NETDB_SUCCESS;
421 			return (&host);
422 #endif
423 		case T_A:
424 		case T_AAAA:
425 			if (strcasecmp(host.h_name, bp) != 0) {
426 				syslog(LOG_NOTICE|LOG_AUTH,
427 				       AskedForGot, host.h_name, bp);
428 				cp += n;
429 				continue;	/* XXX - had_error++ ? */
430 			}
431 			if (n != host.h_length) {
432 				cp += n;
433 				continue;
434 			}
435 			if (type == T_AAAA) {
436 				struct in6_addr in6;
437 				memcpy(&in6, cp, IN6ADDRSZ);
438 				if (IN6_IS_ADDR_V4MAPPED(&in6)) {
439 					cp += n;
440 					continue;
441 				}
442 			}
443 			if (!haveanswer) {
444 				int nn;
445 
446 				host.h_name = bp;
447 				nn = strlen(bp) + 1;	/* for the \0 */
448 				bp += nn;
449 			}
450 
451 			bp += sizeof(align) -
452 			    (size_t)((u_long)bp % sizeof(align));
453 
454 			if (bp + n >= &hostbuf[sizeof hostbuf]) {
455 				dprintf("size (%d) too big\n", n);
456 				had_error++;
457 				continue;
458 			}
459 			if (hap >= &h_addr_ptrs[MAXADDRS-1]) {
460 				if (!toobig++)
461 					dprintf("Too many addresses (%d)\n",
462 						MAXADDRS);
463 				cp += n;
464 				continue;
465 			}
466 			(void)memcpy(*hap++ = bp, cp, (size_t)n);
467 			bp += n;
468 			cp += n;
469 			if (cp != erdata) {
470 				h_errno = NO_RECOVERY;
471 				return (NULL);
472 			}
473 			break;
474 		default:
475 			abort();
476 		}
477 		if (!had_error)
478 			haveanswer++;
479 	}
480 	if (haveanswer) {
481 		*ap = NULL;
482 		*hap = NULL;
483 # if defined(RESOLVSORT)
484 		/*
485 		 * Note: we sort even if host can take only one address
486 		 * in its return structures - should give it the "best"
487 		 * address in that case, not some random one
488 		 */
489 		if (_res.nsort && haveanswer > 1 && qtype == T_A)
490 			addrsort(h_addr_ptrs, haveanswer);
491 # endif /*RESOLVSORT*/
492 		if (!host.h_name) {
493 			n = strlen(qname) + 1;	/* for the \0 */
494 			if (n > ep - bp || n >= MAXHOSTNAMELEN)
495 				goto no_recovery;
496 			strlcpy(bp, qname, (size_t)(ep - bp));
497 			host.h_name = bp;
498 			bp += n;
499 		}
500 		if (_res.options & RES_USE_INET6)
501 			map_v4v6_hostent(&host, &bp, ep);
502 		h_errno = NETDB_SUCCESS;
503 		return (&host);
504 	}
505  no_recovery:
506 	h_errno = NO_RECOVERY;
507 	return (NULL);
508 }
509 
510 struct hostent *
511 gethostbyname(name)
512 	const char *name;
513 {
514 	struct hostent *hp;
515 
516 	_DIAGASSERT(name != NULL);
517 
518 	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
519 		h_errno = NETDB_INTERNAL;
520 		return (NULL);
521 	}
522 	if (_res.options & RES_USE_INET6) {
523 		hp = gethostbyname2(name, AF_INET6);
524 		if (hp)
525 			return (hp);
526 	}
527 	return (gethostbyname2(name, AF_INET));
528 }
529 
530 struct hostent *
531 gethostbyname2(name, af)
532 	const char *name;
533 	int af;
534 {
535 	const char *cp;
536 	char *bp, *ep;
537 	int size;
538 	struct hostent *hp;
539 	static const ns_dtab dtab[] = {
540 		NS_FILES_CB(_gethtbyname, NULL)
541 		{ NSSRC_DNS, _dns_gethtbyname, NULL },	/* force -DHESIOD */
542 		NS_NIS_CB(_yp_gethtbyname, NULL)
543 		{ 0 }
544 	};
545 
546 	_DIAGASSERT(name != NULL);
547 
548 	switch (af) {
549 	case AF_INET:
550 		size = INADDRSZ;
551 		break;
552 	case AF_INET6:
553 		size = IN6ADDRSZ;
554 		break;
555 	default:
556 		h_errno = NETDB_INTERNAL;
557 		errno = EAFNOSUPPORT;
558 		return (NULL);
559 	}
560 
561 	host.h_addrtype = af;
562 	host.h_length = size;
563 
564 	/*
565 	 * if there aren't any dots, it could be a user-level alias.
566 	 * this is also done in res_query() since we are not the only
567 	 * function that looks up host names.
568 	 */
569 	if (!strchr(name, '.') && (cp = __hostalias(name)))
570 		name = cp;
571 
572 	/*
573 	 * disallow names consisting only of digits/dots, unless
574 	 * they end in a dot.
575 	 */
576 	if (isdigit((u_char) name[0]))
577 		for (cp = name;; ++cp) {
578 			if (!*cp) {
579 				if (*--cp == '.')
580 					break;
581 				/*
582 				 * All-numeric, no dot at the end.
583 				 * Fake up a hostent as if we'd actually
584 				 * done a lookup.
585 				 */
586 				if (inet_pton(af, name,
587 				    (char *)(void *)host_addr) <= 0) {
588 					h_errno = HOST_NOT_FOUND;
589 					return (NULL);
590 				}
591 				strncpy(hostbuf, name, MAXDNAME);
592 				hostbuf[MAXDNAME] = '\0';
593 				bp = hostbuf + MAXDNAME;
594 				ep = hostbuf + sizeof hostbuf;
595 				host.h_name = hostbuf;
596 				host.h_aliases = host_aliases;
597 				host_aliases[0] = NULL;
598 				h_addr_ptrs[0] = (char *)(void *)host_addr;
599 				h_addr_ptrs[1] = NULL;
600 				host.h_addr_list = h_addr_ptrs;
601 				if (_res.options & RES_USE_INET6)
602 					map_v4v6_hostent(&host, &bp, ep);
603 				h_errno = NETDB_SUCCESS;
604 				return (&host);
605 			}
606 			if (!isdigit((u_char) *cp) && *cp != '.')
607 				break;
608 		}
609 	if ((isxdigit((u_char) name[0]) && strchr(name, ':') != NULL) ||
610 	    name[0] == ':')
611 		for (cp = name;; ++cp) {
612 			if (!*cp) {
613 				if (*--cp == '.')
614 					break;
615 				/*
616 				 * All-IPv6-legal, no dot at the end.
617 				 * Fake up a hostent as if we'd actually
618 				 * done a lookup.
619 				 */
620 				if (inet_pton(af, name,
621 				    (char *)(void *)host_addr) <= 0) {
622 					h_errno = HOST_NOT_FOUND;
623 					return (NULL);
624 				}
625 				strncpy(hostbuf, name, MAXDNAME);
626 				hostbuf[MAXDNAME] = '\0';
627 				bp = hostbuf + MAXDNAME;
628 				ep = hostbuf + sizeof hostbuf;
629 				host.h_name = hostbuf;
630 				host.h_aliases = host_aliases;
631 				host_aliases[0] = NULL;
632 				h_addr_ptrs[0] = (char *)(void *)host_addr;
633 				h_addr_ptrs[1] = NULL;
634 				host.h_addr_list = h_addr_ptrs;
635 				h_errno = NETDB_SUCCESS;
636 				return (&host);
637 			}
638 			if (!isxdigit((u_char) *cp) && *cp != ':' && *cp != '.')
639 				break;
640 		}
641 
642 	hp = (struct hostent *)NULL;
643 	h_errno = NETDB_INTERNAL;
644 	if (nsdispatch(&hp, dtab, NSDB_HOSTS, "gethostbyname",
645 	    default_dns_files, name, strlen(name), af) != NS_SUCCESS)
646 		return (struct hostent *)NULL;
647 	h_errno = NETDB_SUCCESS;
648 	return (hp);
649 }
650 
651 struct hostent *
652 gethostbyaddr(addr, len, af)
653 	const char *addr;	/* XXX should have been def'd as u_char! */
654 	socklen_t len;
655 	int af;
656 {
657 	const u_char *uaddr = (const u_char *)addr;
658 	socklen_t size;
659 	struct hostent *hp;
660 	static const ns_dtab dtab[] = {
661 		NS_FILES_CB(_gethtbyaddr, NULL)
662 		{ NSSRC_DNS, _dns_gethtbyaddr, NULL },	/* force -DHESIOD */
663 		NS_NIS_CB(_yp_gethtbyaddr, NULL)
664 		{ 0 }
665 	};
666 
667 	_DIAGASSERT(addr != NULL);
668 
669 	if (af == AF_INET6 && len == IN6ADDRSZ &&
670 	    (IN6_IS_ADDR_LINKLOCAL((const struct in6_addr *)(const void *)uaddr) ||
671 	     IN6_IS_ADDR_SITELOCAL((const struct in6_addr *)(const void *)uaddr))) {
672 		h_errno = HOST_NOT_FOUND;
673 		return (NULL);
674 	}
675 	if (af == AF_INET6 && len == IN6ADDRSZ &&
676 	    (IN6_IS_ADDR_V4MAPPED((const struct in6_addr *)(const void *)uaddr) ||
677 	     IN6_IS_ADDR_V4COMPAT((const struct in6_addr *)(const void *)uaddr))) {
678 		/* Unmap. */
679 		addr += IN6ADDRSZ - INADDRSZ;
680 		uaddr += IN6ADDRSZ - INADDRSZ;
681 		af = AF_INET;
682 		len = INADDRSZ;
683 	}
684 	switch (af) {
685 	case AF_INET:
686 		size = INADDRSZ;
687 		break;
688 	case AF_INET6:
689 		size = IN6ADDRSZ;
690 		break;
691 	default:
692 		errno = EAFNOSUPPORT;
693 		h_errno = NETDB_INTERNAL;
694 		return (NULL);
695 	}
696 	if (size != len) {
697 		errno = EINVAL;
698 		h_errno = NETDB_INTERNAL;
699 		return (NULL);
700 	}
701 	hp = (struct hostent *)NULL;
702 	h_errno = NETDB_INTERNAL;
703 	if (nsdispatch(&hp, dtab, NSDB_HOSTS, "gethostbyaddr",
704 	    default_dns_files, uaddr, len, af) != NS_SUCCESS)
705 		return (struct hostent *)NULL;
706 	h_errno = NETDB_SUCCESS;
707 	return (hp);
708 }
709 
710 void
711 _sethtent(f)
712 	int f;
713 {
714 	if (!hostf)
715 		hostf = fopen(_PATH_HOSTS, "r" );
716 	else
717 		rewind(hostf);
718 	stayopen = f;
719 }
720 
721 void
722 _endhtent()
723 {
724 	if (hostf && !stayopen) {
725 		(void) fclose(hostf);
726 		hostf = NULL;
727 	}
728 }
729 
730 struct hostent *
731 _gethtent()
732 {
733 	char *p;
734 	char *cp, **q;
735 	int af, len;
736 
737 	if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" ))) {
738 		h_errno = NETDB_INTERNAL;
739 		return (NULL);
740 	}
741  again:
742 	if (!(p = fgets(hostbuf, sizeof hostbuf, hostf))) {
743 		h_errno = HOST_NOT_FOUND;
744 		return (NULL);
745 	}
746 	if (*p == '#')
747 		goto again;
748 	if (!(cp = strpbrk(p, "#\n")))
749 		goto again;
750 	*cp = '\0';
751 	if (!(cp = strpbrk(p, " \t")))
752 		goto again;
753 	*cp++ = '\0';
754 	if (inet_pton(AF_INET6, p, (char *)(void *)host_addr) > 0) {
755 		af = AF_INET6;
756 		len = IN6ADDRSZ;
757 	} else if (inet_pton(AF_INET, p, (char *)(void *)host_addr) > 0) {
758 		if (_res.options & RES_USE_INET6) {
759 			map_v4v6_address((char *)(void *)host_addr,
760 			    (char *)(void *)host_addr);
761 			af = AF_INET6;
762 			len = IN6ADDRSZ;
763 		} else {
764 			af = AF_INET;
765 			len = INADDRSZ;
766 		}
767 	} else {
768 		goto again;
769 	}
770 	/* if this is not something we're looking for, skip it. */
771 	if (host.h_addrtype != af)
772 		goto again;
773 	if (host.h_length != len)
774 		goto again;
775 	h_addr_ptrs[0] = (char *)(void *)host_addr;
776 	h_addr_ptrs[1] = NULL;
777 	host.h_addr_list = h_addr_ptrs;
778 	host.h_length = len;
779 	host.h_addrtype = af;
780 	while (*cp == ' ' || *cp == '\t')
781 		cp++;
782 	host.h_name = cp;
783 	q = host.h_aliases = host_aliases;
784 	if ((cp = strpbrk(cp, " \t")) != NULL)
785 		*cp++ = '\0';
786 	while (cp && *cp) {
787 		if (*cp == ' ' || *cp == '\t') {
788 			cp++;
789 			continue;
790 		}
791 		if (q < &host_aliases[MAXALIASES - 1])
792 			*q++ = cp;
793 		if ((cp = strpbrk(cp, " \t")) != NULL)
794 			*cp++ = '\0';
795 	}
796 	*q = NULL;
797 	h_errno = NETDB_SUCCESS;
798 	return (&host);
799 }
800 
801 /*ARGSUSED*/
802 int
803 _gethtbyname(rv, cb_data, ap)
804 	void	*rv;
805 	void	*cb_data;
806 	va_list	 ap;
807 {
808 	struct hostent *hp;
809 	const char *name;
810 	int af;
811 
812 	_DIAGASSERT(rv != NULL);
813 
814 	name = va_arg(ap, char *);
815 	/* NOSTRICT skip len */(void)va_arg(ap, int);
816 	af = va_arg(ap, int);
817 
818 	hp = NULL;
819 #if 0
820 	if (_res.options & RES_USE_INET6)
821 		hp = _gethtbyname2(name, AF_INET6);
822 	if (hp==NULL)
823 		hp = _gethtbyname2(name, AF_INET);
824 #else
825 	hp = _gethtbyname2(name, af);
826 #endif
827 	*((struct hostent **)rv) = hp;
828 	if (hp == NULL) {
829 		h_errno = HOST_NOT_FOUND;
830 		return NS_NOTFOUND;
831 	}
832 	return NS_SUCCESS;
833 }
834 
835 struct hostent *
836 _gethtbyname2(name, af)
837 	const char *name;
838 	int af;
839 {
840 	struct hostent *p;
841 	char *tmpbuf, *ptr, **cp;
842 	int num;
843 	size_t len;
844 
845 	_DIAGASSERT(name != NULL);
846 
847 	_sethtent(0);
848 	ptr = tmpbuf = NULL;
849 	num = 0;
850 	while ((p = _gethtent()) != NULL && num < MAXADDRS) {
851 		if (p->h_addrtype != af)
852 			continue;
853 		if (strcasecmp(p->h_name, name) != 0) {
854 			for (cp = p->h_aliases; *cp != NULL; cp++)
855 				if (strcasecmp(*cp, name) == 0)
856 					break;
857 			if (*cp == NULL) continue;
858 		}
859 
860 		if (num == 0) {
861 			size_t bufsize;
862 			char *src;
863 
864 			bufsize = strlen(p->h_name) + 2 +
865 				  MAXADDRS * p->h_length +
866 				  ALIGNBYTES;
867 			for (cp = p->h_aliases; *cp != NULL; cp++)
868 				bufsize += strlen(*cp) + 1;
869 
870 			if ((tmpbuf = malloc(bufsize)) == NULL) {
871 				h_errno = NETDB_INTERNAL;
872 				return NULL;
873 			}
874 
875 			ptr = tmpbuf;
876 			src = p->h_name;
877 			while ((*ptr++ = *src++) != '\0');
878 			for (cp = p->h_aliases; *cp != NULL; cp++) {
879 				src = *cp;
880 				while ((*ptr++ = *src++) != '\0');
881 			}
882 			*ptr++ = '\0';
883 
884 			ptr = (char *)(void *)ALIGN(ptr);
885 		}
886 
887 		(void)memcpy(ptr, p->h_addr_list[0], (size_t)p->h_length);
888 		ptr += p->h_length;
889 		num++;
890 	}
891 	_endhtent();
892 	if (num == 0) return NULL;
893 
894 	len = ptr - tmpbuf;
895 	if (len > (sizeof(hostbuf) - ALIGNBYTES)) {
896 		free(tmpbuf);
897 		errno = ENOSPC;
898 		h_errno = NETDB_INTERNAL;
899 		return NULL;
900 	}
901 	ptr = memcpy((void *)ALIGN(hostbuf), tmpbuf, len);
902 	free(tmpbuf);
903 
904 	host.h_name = ptr;
905 	while (*ptr++);
906 
907 	cp = host_aliases;
908 	while (*ptr) {
909 		*cp++ = ptr;
910 		while (*ptr++);
911 	}
912 	ptr++;
913 	*cp = NULL;
914 
915 	ptr = (char *)(void *)ALIGN(ptr);
916 	cp = h_addr_ptrs;
917 	while (num--) {
918 		*cp++ = ptr;
919 		ptr += host.h_length;
920 	}
921 	*cp = NULL;
922 
923 	return (&host);
924 }
925 
926 /*ARGSUSED*/
927 int
928 _gethtbyaddr(rv, cb_data, ap)
929 	void	*rv;
930 	void	*cb_data;
931 	va_list	 ap;
932 {
933 	struct hostent *p;
934 	const unsigned char *addr;
935 	int len, af;
936 
937 	_DIAGASSERT(rv != NULL);
938 
939 	addr = va_arg(ap, unsigned char *);
940 	len = va_arg(ap, int);
941 	af = va_arg(ap, int);
942 
943 	host.h_length = len;
944 	host.h_addrtype = af;
945 
946 	_sethtent(0);
947 	while ((p = _gethtent()) != NULL)
948 		if (p->h_addrtype == af && !memcmp(p->h_addr, addr,
949 		    (size_t)len))
950 			break;
951 	_endhtent();
952 	*((struct hostent **)rv) = p;
953 	if (p==NULL) {
954 		h_errno = HOST_NOT_FOUND;
955 		return NS_NOTFOUND;
956 	}
957 	return NS_SUCCESS;
958 }
959 
960 static void
961 map_v4v6_address(src, dst)
962 	const char *src;
963 	char *dst;
964 {
965 	u_char *p = (u_char *)dst;
966 	char tmp[INADDRSZ];
967 	int i;
968 
969 	_DIAGASSERT(src != NULL);
970 	_DIAGASSERT(dst != NULL);
971 
972 	/* Stash a temporary copy so our caller can update in place. */
973 	(void)memcpy(tmp, src, INADDRSZ);
974 	/* Mark this ipv6 addr as a mapped ipv4. */
975 	for (i = 0; i < 10; i++)
976 		*p++ = 0x00;
977 	*p++ = 0xff;
978 	*p++ = 0xff;
979 	/* Retrieve the saved copy and we're done. */
980 	(void)memcpy((void *)p, tmp, INADDRSZ);
981 }
982 
983 static void
984 map_v4v6_hostent(hp, bpp, ep)
985 	struct hostent *hp;
986 	char **bpp;
987 	char *ep;
988 {
989 	char **ap;
990 
991 	_DIAGASSERT(hp != NULL);
992 	_DIAGASSERT(bpp != NULL);
993 	_DIAGASSERT(ep != NULL);
994 
995 	if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
996 		return;
997 	hp->h_addrtype = AF_INET6;
998 	hp->h_length = IN6ADDRSZ;
999 	for (ap = hp->h_addr_list; *ap; ap++) {
1000 		int i = sizeof(align) - (size_t)((u_long)*bpp % sizeof(align));
1001 
1002 		if (ep - *bpp < (i + IN6ADDRSZ)) {
1003 			/* Out of memory.  Truncate address list here.  XXX */
1004 			*ap = NULL;
1005 			return;
1006 		}
1007 		*bpp += i;
1008 		map_v4v6_address(*ap, *bpp);
1009 		*ap = *bpp;
1010 		*bpp += IN6ADDRSZ;
1011 	}
1012 }
1013 
1014 #ifdef RESOLVSORT
1015 static void
1016 addrsort(ap, num)
1017 	char **ap;
1018 	int num;
1019 {
1020 	int i, j;
1021 	char **p;
1022 	short aval[MAXADDRS];
1023 	int needsort = 0;
1024 
1025 	_DIAGASSERT(ap != NULL);
1026 
1027 	p = ap;
1028 	for (i = 0; i < num; i++, p++) {
1029 	    for (j = 0 ; (unsigned)j < _res.nsort; j++)
1030 		if (_res.sort_list[j].addr.s_addr ==
1031 		    (((struct in_addr *)(void *)(*p))->s_addr &
1032 		    _res.sort_list[j].mask))
1033 			break;
1034 	    aval[i] = j;
1035 	    if (needsort == 0 && i > 0 && j < aval[i-1])
1036 		needsort = i;
1037 	}
1038 	if (!needsort)
1039 	    return;
1040 
1041 	while (needsort < num) {
1042 	    for (j = needsort - 1; j >= 0; j--) {
1043 		if (aval[j] > aval[j+1]) {
1044 		    char *hp;
1045 
1046 		    i = aval[j];
1047 		    aval[j] = aval[j+1];
1048 		    aval[j+1] = i;
1049 
1050 		    hp = ap[j];
1051 		    ap[j] = ap[j+1];
1052 		    ap[j+1] = hp;
1053 		} else
1054 		    break;
1055 	    }
1056 	    needsort++;
1057 	}
1058 }
1059 #endif
1060 
1061 #if defined(BSD43_BSD43_NFS) || defined(sun)
1062 /* XXX: should we remove this cruft? - lukem */
1063 /* some libc's out there are bound internally to these names (UMIPS) */
1064 void
1065 ht_sethostent(stayopen)
1066 	int stayopen;
1067 {
1068 	_sethtent(stayopen);
1069 }
1070 
1071 void
1072 ht_endhostent()
1073 {
1074 	_endhtent();
1075 }
1076 
1077 struct hostent *
1078 ht_gethostbyname(name)
1079 	char *name;
1080 {
1081 	return (_gethtbyname(name));
1082 }
1083 
1084 struct hostent *
1085 ht_gethostbyaddr(addr, len, af)
1086 	const char *addr;
1087 	int len, af;
1088 {
1089 	return (_gethtbyaddr(addr, len, af));
1090 }
1091 
1092 struct hostent *
1093 gethostent()
1094 {
1095 	return (_gethtent());
1096 }
1097 
1098 void
1099 dns_service()
1100 {
1101 	return;
1102 }
1103 
1104 int
1105 dn_skipname(comp_dn, eom)
1106 	const u_char *comp_dn, *eom;
1107 {
1108 	return (__dn_skipname(comp_dn, eom));
1109 }
1110 #endif /*old-style libc with yp junk in it*/
1111 
1112 /*ARGSUSED*/
1113 int
1114 _dns_gethtbyname(rv, cb_data, ap)
1115 	void	*rv;
1116 	void	*cb_data;
1117 	va_list	 ap;
1118 {
1119 	querybuf *buf;
1120 	int n, type;
1121 	struct hostent *hp;
1122 	const char *name;
1123 	int af;
1124 
1125 	_DIAGASSERT(rv != NULL);
1126 
1127 	name = va_arg(ap, char *);
1128 	/* NOSTRICT skip len */(void)va_arg(ap, int);
1129 	af = va_arg(ap, int);
1130 
1131 	switch (af) {
1132 	case AF_INET:
1133 		type = T_A;
1134 		break;
1135 	case AF_INET6:
1136 		type = T_AAAA;
1137 		break;
1138 	default:
1139 		return NS_UNAVAIL;
1140 	}
1141 	buf = malloc(sizeof(*buf));
1142 	if (buf == NULL) {
1143 		h_errno = NETDB_INTERNAL;
1144 		return NS_NOTFOUND;
1145 	}
1146 	n = res_search(name, C_IN, type, buf->buf, sizeof(buf->buf));
1147 	if (n < 0) {
1148 		free(buf);
1149 		dprintf("res_search failed (%d)\n", n);
1150 		return NS_NOTFOUND;
1151 	}
1152 	hp = getanswer(buf, n, name, type);
1153 	free(buf);
1154 	if (hp == NULL)
1155 		switch (h_errno) {
1156 		case HOST_NOT_FOUND:
1157 			return NS_NOTFOUND;
1158 		case TRY_AGAIN:
1159 			return NS_TRYAGAIN;
1160 		default:
1161 			return NS_UNAVAIL;
1162 		}
1163 	*((struct hostent **)rv) = hp;
1164 	return NS_SUCCESS;
1165 }
1166 
1167 /*ARGSUSED*/
1168 int
1169 _dns_gethtbyaddr(rv, cb_data, ap)
1170 	void	*rv;
1171 	void	*cb_data;
1172 	va_list	 ap;
1173 {
1174 	char qbuf[MAXDNAME + 1], *qp, *ep;
1175 	int n;
1176 	querybuf *buf;
1177 	struct hostent *hp;
1178 	const unsigned char *uaddr;
1179 	int len, af, advance;
1180 
1181 	_DIAGASSERT(rv != NULL);
1182 
1183 	uaddr = va_arg(ap, unsigned char *);
1184 	len = va_arg(ap, int);
1185 	af = va_arg(ap, int);
1186 
1187 	switch (af) {
1188 	case AF_INET:
1189 		(void)snprintf(qbuf, sizeof(qbuf), "%u.%u.%u.%u.in-addr.arpa",
1190 		    (uaddr[3] & 0xff), (uaddr[2] & 0xff),
1191 		    (uaddr[1] & 0xff), (uaddr[0] & 0xff));
1192 		break;
1193 
1194 	case AF_INET6:
1195 		qp = qbuf;
1196 		ep = qbuf + sizeof(qbuf) - 1;
1197 		for (n = IN6ADDRSZ - 1; n >= 0; n--) {
1198 			advance = snprintf(qp, (size_t)(ep - qp), "%x.%x.",
1199 			    uaddr[n] & 0xf,
1200 			    ((unsigned int)uaddr[n] >> 4) & 0xf);
1201 			if (advance > 0 && qp + advance < ep)
1202 				qp += advance;
1203 			else {
1204 				h_errno = NETDB_INTERNAL;
1205 				return NS_NOTFOUND;
1206 			}
1207 		}
1208 		if (strlcat(qbuf, "ip6.arpa", sizeof(qbuf)) >= sizeof(qbuf)) {
1209 			h_errno = NETDB_INTERNAL;
1210 			return NS_NOTFOUND;
1211 		}
1212 		break;
1213 	default:
1214 		abort();
1215 	}
1216 
1217 	buf = malloc(sizeof(*buf));
1218 	if (buf == NULL) {
1219 		h_errno = NETDB_INTERNAL;
1220 		return NS_NOTFOUND;
1221 	}
1222 	n = res_query(qbuf, C_IN, T_PTR, buf->buf, sizeof(buf->buf));
1223 	if (n < 0 && af == AF_INET6) {
1224 		*qp = '\0';
1225 		if (strlcat(qbuf, "ip6.int", sizeof(qbuf)) >= sizeof(qbuf)) {
1226 			free(buf);
1227 			h_errno = NETDB_INTERNAL;
1228 			return NS_NOTFOUND;
1229 		}
1230 		n = res_query(qbuf, C_IN, T_PTR, buf->buf, sizeof(buf->buf));
1231 	}
1232 	if (n < 0) {
1233 		free(buf);
1234 		dprintf("res_query failed (%d)\n", n);
1235 		return NS_NOTFOUND;
1236 	}
1237 	hp = getanswer(buf, n, qbuf, T_PTR);
1238 	free(buf);
1239 	if (hp == NULL)
1240 		switch (h_errno) {
1241 		case HOST_NOT_FOUND:
1242 			return NS_NOTFOUND;
1243 		case TRY_AGAIN:
1244 			return NS_TRYAGAIN;
1245 		default:
1246 			return NS_UNAVAIL;
1247 		}
1248 	hp->h_addrtype = af;
1249 	hp->h_length = len;
1250 	(void)memcpy(host_addr, uaddr, (size_t)len);
1251 	h_addr_ptrs[0] = (char *)(void *)host_addr;
1252 	h_addr_ptrs[1] = NULL;
1253 	if (af == AF_INET && (_res.options & RES_USE_INET6)) {
1254 		map_v4v6_address((char *)(void *)host_addr,
1255 		    (char *)(void *)host_addr);
1256 		hp->h_addrtype = AF_INET6;
1257 		hp->h_length = IN6ADDRSZ;
1258 	}
1259 
1260 	*((struct hostent **)rv) = hp;
1261 	h_errno = NETDB_SUCCESS;
1262 	return NS_SUCCESS;
1263 }
1264 
1265 #ifdef YP
1266 /*ARGSUSED*/
1267 struct hostent *
1268 _yphostent(line, af)
1269 	char *line;
1270 	int af;
1271 {
1272 	static struct in_addr host_addrs[MAXADDRS];
1273 	static struct in6_addr host6_addrs[MAXADDRS];
1274 	char *p = line;
1275 	char *cp, **q;
1276 	char **hap;
1277 	int addrok;
1278 	int more;
1279 	size_t naddrs;
1280 
1281 	_DIAGASSERT(line != NULL);
1282 
1283 	host.h_name = NULL;
1284 	host.h_addr_list = h_addr_ptrs;
1285 	host.h_addrtype = af;
1286 	switch (af) {
1287 	case AF_INET:
1288 		host.h_length = INADDRSZ;
1289 		break;
1290 	case AF_INET6:
1291 		host.h_length = IN6ADDRSZ;
1292 		break;
1293 	default:
1294 		return (NULL);
1295 	}
1296 	hap = h_addr_ptrs;
1297 	q = host.h_aliases = host_aliases;
1298 	naddrs = 0;
1299 
1300 nextline:
1301 	/* check for host_addrs overflow */
1302 	if (naddrs >= sizeof(host_addrs) / sizeof(host_addrs[0]))
1303 		goto done;
1304 	if (naddrs >= sizeof(host6_addrs) / sizeof(host6_addrs[0]))
1305 		goto done;
1306 
1307 	more = 0;
1308 	cp = strpbrk(p, " \t");
1309 	if (cp == NULL)
1310 		goto done;
1311 	*cp++ = '\0';
1312 
1313 	/* p has should have an address */
1314 	switch (af) {
1315 	case AF_INET:
1316 		addrok = inet_aton(p, &host_addrs[naddrs]);
1317 		break;
1318 	case AF_INET6:
1319 		addrok = inet_pton(af, p, &host6_addrs[naddrs]);
1320 		break;
1321 	}
1322 	if (addrok != 1) {
1323 		/* skip to the next line */
1324 		while (cp && *cp) {
1325 			if (*cp == '\n') {
1326 				cp++;
1327 				goto nextline;
1328 			}
1329 			cp++;
1330 		}
1331 
1332 		goto done;
1333 	}
1334 
1335 	switch (af) {
1336 	case AF_INET:
1337 		*hap++ = (char *)(void *)&host_addrs[naddrs++];
1338 		break;
1339 	case AF_INET6:
1340 		*hap++ = (char *)(void *)&host6_addrs[naddrs++];
1341 		break;
1342 	}
1343 
1344 	while (*cp == ' ' || *cp == '\t')
1345 		cp++;
1346 	p = cp;
1347 	cp = strpbrk(p, " \t\n");
1348 	if (cp != NULL) {
1349 		if (*cp == '\n')
1350 			more = 1;
1351 		*cp++ = '\0';
1352 	}
1353 	if (!host.h_name)
1354 		host.h_name = p;
1355 	else if (strcmp(host.h_name, p)==0)
1356 		;
1357 	else if (q < &host_aliases[MAXALIASES - 1])
1358 		*q++ = p;
1359 	p = cp;
1360 	if (more)
1361 		goto nextline;
1362 
1363 	while (cp && *cp) {
1364 		if (*cp == ' ' || *cp == '\t') {
1365 			cp++;
1366 			continue;
1367 		}
1368 		if (*cp == '\n') {
1369 			cp++;
1370 			goto nextline;
1371 		}
1372 		if (q < &host_aliases[MAXALIASES - 1])
1373 			*q++ = cp;
1374 		cp = strpbrk(cp, " \t");
1375 		if (cp != NULL)
1376 			*cp++ = '\0';
1377 	}
1378 
1379 done:
1380 	if (host.h_name == NULL)
1381 		return (NULL);
1382 	*q = NULL;
1383 	*hap = NULL;
1384 	return (&host);
1385 }
1386 
1387 /*ARGSUSED*/
1388 int
1389 _yp_gethtbyaddr(rv, cb_data, ap)
1390 	void	*rv;
1391 	void	*cb_data;
1392 	va_list	 ap;
1393 {
1394 	struct hostent *hp = (struct hostent *)NULL;
1395 	static char *__ypcurrent;
1396 	int __ypcurrentlen, r;
1397 	char name[INET6_ADDRSTRLEN];	/* XXX enough? */
1398 	const unsigned char *uaddr;
1399 	int af;
1400 	const char *map;
1401 
1402 	_DIAGASSERT(rv != NULL);
1403 
1404 	uaddr = va_arg(ap, unsigned char *);
1405 	/* NOSTRICT skip len */(void)va_arg(ap, int);
1406 	af = va_arg(ap, int);
1407 
1408 	if (!__ypdomain) {
1409 		if (_yp_check(&__ypdomain) == 0)
1410 			return NS_UNAVAIL;
1411 	}
1412 	/*
1413 	 * XXX unfortunately, we cannot support IPv6 extended scoped address
1414 	 * notation here.  gethostbyaddr() is not scope-aware.  too bad.
1415 	 */
1416 	if (inet_ntop(af, uaddr, name, sizeof(name)) == NULL)
1417 		return NS_UNAVAIL;
1418 	if (__ypcurrent)
1419 		free(__ypcurrent);
1420 	__ypcurrent = NULL;
1421 	switch (af) {
1422 	case AF_INET:
1423 		map = "hosts.byaddr";
1424 		break;
1425 	default:
1426 		map = "ipnodes.byaddr";
1427 		break;
1428 	}
1429 	r = yp_match(__ypdomain, map, name,
1430 		(int)strlen(name), &__ypcurrent, &__ypcurrentlen);
1431 	if (r==0)
1432 		hp = _yphostent(__ypcurrent, af);
1433 	if (hp==NULL) {
1434 		h_errno = HOST_NOT_FOUND;
1435 		return NS_NOTFOUND;
1436 	}
1437 	*((struct hostent **)rv) = hp;
1438 	return NS_SUCCESS;
1439 }
1440 
1441 /*ARGSUSED*/
1442 int
1443 _yp_gethtbyname(rv, cb_data, ap)
1444 	void	*rv;
1445 	void	*cb_data;
1446 	va_list	 ap;
1447 {
1448 	struct hostent *hp = (struct hostent *)NULL;
1449 	static char *__ypcurrent;
1450 	int __ypcurrentlen, r;
1451 	const char *name;
1452 	int af;
1453 	const char *map;
1454 
1455 	_DIAGASSERT(rv != NULL);
1456 
1457 	name = va_arg(ap, char *);
1458 	/* NOSTRICT skip len */(void)va_arg(ap, int);
1459 	af = va_arg(ap, int);
1460 
1461 	if (!__ypdomain) {
1462 		if (_yp_check(&__ypdomain) == 0)
1463 			return NS_UNAVAIL;
1464 	}
1465 	if (__ypcurrent)
1466 		free(__ypcurrent);
1467 	__ypcurrent = NULL;
1468 	switch (af) {
1469 	case AF_INET:
1470 		map = "hosts.byname";
1471 		break;
1472 	default:
1473 		map = "ipnodes.byname";
1474 		break;
1475 	}
1476 	r = yp_match(__ypdomain, map, name,
1477 		(int)strlen(name), &__ypcurrent, &__ypcurrentlen);
1478 	if (r==0)
1479 		hp = _yphostent(__ypcurrent, af);
1480 	if (hp==NULL) {
1481 		h_errno = HOST_NOT_FOUND;
1482 		return NS_NOTFOUND;
1483 	}
1484 	*((struct hostent **)rv) = hp;
1485 	return NS_SUCCESS;
1486 }
1487 #endif
1488