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1 /*	$NetBSD: gethnamaddr.c,v 1.70 2006/03/22 00:03:51 christos 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 #include <sys/types.h>
56 
57 #include <sys/param.h>
58 #include <sys/socket.h>
59 #include <sys/un.h>
60 #include <netinet/in.h>
61 #include <arpa/inet.h>
62 #include <arpa/nameser.h>
63 #include "NetdClientDispatch.h"
64 #include "resolv_netid.h"
65 #include "resolv_private.h"
66 #include "resolv_cache.h"
67 #include <assert.h>
68 #include <ctype.h>
69 #include <errno.h>
70 #include <netdb.h>
71 #include <stdarg.h>
72 #include <stdio.h>
73 #include <strings.h>
74 #include <syslog.h>
75 #include <unistd.h>
76 
77 #define ALIGNBYTES (sizeof(uintptr_t) - 1)
78 #define ALIGN(p) (((uintptr_t)(p) + ALIGNBYTES) &~ ALIGNBYTES)
79 
80 #ifndef LOG_AUTH
81 # define LOG_AUTH 0
82 #endif
83 
84 #define MULTI_PTRS_ARE_ALIASES 1	/* XXX - experimental */
85 
86 #include "nsswitch.h"
87 #include <stdlib.h>
88 #include <string.h>
89 
90 // This should be synchronized to ResponseCode.h
91 static const int DnsProxyQueryResult = 222;
92 
93 static const char AskedForGot[] =
94 			  "gethostby*.getanswer: asked for \"%s\", got \"%s\"";
95 
96 #define	MAXPACKET	(64*1024)
97 
98 typedef union {
99     HEADER hdr;
100     u_char buf[MAXPACKET];
101 } querybuf;
102 
103 typedef union {
104     int32_t al;
105     char ac;
106 } align;
107 
108 #ifdef DEBUG
109 static void dprintf(const char *, res_state, ...)
110 	__attribute__((__format__(__printf__, 1, 3)));
111 #endif
112 static struct hostent *getanswer(const querybuf *, int, const char *, int,
113     res_state);
114 static void map_v4v6_address(const char *, char *);
115 static void map_v4v6_hostent(struct hostent *, char **, char *);
116 static void addrsort(char **, int, res_state);
117 
118 static void _sethtent(int);
119 static void _endhtent(void);
120 static struct hostent *_gethtent(void);
121 void ht_sethostent(int);
122 void ht_endhostent(void);
123 struct hostent *ht_gethostbyname(char *);
124 struct hostent *ht_gethostbyaddr(const char *, int, int);
125 void dns_service(void);
126 #undef dn_skipname
127 int dn_skipname(const u_char *, const u_char *);
128 static int _gethtbyaddr(void *, void *, va_list);
129 static int _gethtbyname(void *, void *, va_list);
130 static struct hostent *_gethtbyname2(const char *, int);
131 static int _dns_gethtbyaddr(void *, void *, va_list);
132 static int _dns_gethtbyname(void *, void *, va_list);
133 
134 static struct hostent *gethostbyname_internal(const char *, int, res_state, unsigned, unsigned);
135 
136 static const ns_src default_dns_files[] = {
137 	{ NSSRC_FILES, 	NS_SUCCESS },
138 	{ NSSRC_DNS, 	NS_SUCCESS },
139 	{ 0, 0 }
140 };
141 
142 
143 #ifdef DEBUG
144 static void
dprintf(const char * msg,res_state res,...)145 dprintf(const char *msg, res_state res, ...)
146 {
147 	assert(msg != NULL);
148 
149 	if (res->options & RES_DEBUG) {
150 		int save = errno;
151 		va_list ap;
152 
153 		va_start (ap, res);
154 		vprintf(msg, ap);
155 		va_end (ap);
156 
157 		errno = save;
158 	}
159 }
160 #else
161 # define dprintf(msg, res, num) ((void)0) /*nada*/
162 #endif
163 
164 #define BOUNDED_INCR(x) \
165 	do { \
166 		cp += (x); \
167 		if (cp > eom) { \
168 			h_errno = NO_RECOVERY; \
169 			return NULL; \
170 		} \
171 	} while (/*CONSTCOND*/0)
172 
173 #define BOUNDS_CHECK(ptr, count) \
174 	do { \
175 		if ((ptr) + (count) > eom) { \
176 			h_errno = NO_RECOVERY; \
177 			return NULL; \
178 		} \
179 	} while (/*CONSTCOND*/0)
180 
181 static struct hostent *
getanswer(const querybuf * answer,int anslen,const char * qname,int qtype,res_state res)182 getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
183     res_state res)
184 {
185 	const HEADER *hp;
186 	const u_char *cp;
187 	int n;
188 	const u_char *eom, *erdata;
189 	char *bp, **ap, **hap, *ep;
190 	int type, class, ancount, qdcount;
191 	int haveanswer, had_error;
192 	int toobig = 0;
193 	char tbuf[MAXDNAME];
194 	const char *tname;
195 	int (*name_ok)(const char *);
196 	res_static  rs = __res_get_static();
197 
198 	assert(answer != NULL);
199 	assert(qname != NULL);
200 
201 	tname = qname;
202 	rs->host.h_name = NULL;
203 	eom = answer->buf + anslen;
204 	switch (qtype) {
205 	case T_A:
206 	case T_AAAA:
207 		name_ok = res_hnok;
208 		break;
209 	case T_PTR:
210 		name_ok = res_dnok;
211 		break;
212 	default:
213 		return NULL;	/* XXX should be abort(); */
214 	}
215 	/*
216 	 * find first satisfactory answer
217 	 */
218 	hp = &answer->hdr;
219 	ancount = ntohs(hp->ancount);
220 	qdcount = ntohs(hp->qdcount);
221 	bp = rs->hostbuf;
222 	ep = rs->hostbuf + sizeof rs->hostbuf;
223 	cp = answer->buf;
224 	BOUNDED_INCR(HFIXEDSZ);
225 	if (qdcount != 1) {
226 		h_errno = NO_RECOVERY;
227 		return NULL;
228 	}
229 	n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
230 	if ((n < 0) || !(*name_ok)(bp)) {
231 		h_errno = NO_RECOVERY;
232 		return NULL;
233 	}
234 	BOUNDED_INCR(n + QFIXEDSZ);
235 	if (qtype == T_A || qtype == T_AAAA) {
236 		/* res_send() has already verified that the query name is the
237 		 * same as the one we sent; this just gets the expanded name
238 		 * (i.e., with the succeeding search-domain tacked on).
239 		 */
240 		n = strlen(bp) + 1;		/* for the \0 */
241 		if (n >= MAXHOSTNAMELEN) {
242 			h_errno = NO_RECOVERY;
243 			return NULL;
244 		}
245 		rs->host.h_name = bp;
246 		bp += n;
247 		/* The qname can be abbreviated, but h_name is now absolute. */
248 		qname = rs->host.h_name;
249 	}
250 	ap = rs->host_aliases;
251 	*ap = NULL;
252 	rs->host.h_aliases = rs->host_aliases;
253 	hap = rs->h_addr_ptrs;
254 	*hap = NULL;
255 	rs->host.h_addr_list = rs->h_addr_ptrs;
256 	haveanswer = 0;
257 	had_error = 0;
258 	while (ancount-- > 0 && cp < eom && !had_error) {
259 		n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
260 		if ((n < 0) || !(*name_ok)(bp)) {
261 			had_error++;
262 			continue;
263 		}
264 		cp += n;			/* name */
265 		BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
266 		type = _getshort(cp);
267  		cp += INT16SZ;			/* type */
268 		class = _getshort(cp);
269  		cp += INT16SZ + INT32SZ;	/* class, TTL */
270 		n = _getshort(cp);
271 		cp += INT16SZ;			/* len */
272 		BOUNDS_CHECK(cp, n);
273 		erdata = cp + n;
274 		if (class != C_IN) {
275 			/* XXX - debug? syslog? */
276 			cp += n;
277 			continue;		/* XXX - had_error++ ? */
278 		}
279 		if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
280 			if (ap >= &rs->host_aliases[MAXALIASES-1])
281 				continue;
282 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
283 			if ((n < 0) || !(*name_ok)(tbuf)) {
284 				had_error++;
285 				continue;
286 			}
287 			cp += n;
288 			if (cp != erdata) {
289 				h_errno = NO_RECOVERY;
290 				return NULL;
291 			}
292 			/* Store alias. */
293 			*ap++ = bp;
294 			n = strlen(bp) + 1;	/* for the \0 */
295 			if (n >= MAXHOSTNAMELEN) {
296 				had_error++;
297 				continue;
298 			}
299 			bp += n;
300 			/* Get canonical name. */
301 			n = strlen(tbuf) + 1;	/* for the \0 */
302 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
303 				had_error++;
304 				continue;
305 			}
306 			strlcpy(bp, tbuf, (size_t)(ep - bp));
307 			rs->host.h_name = bp;
308 			bp += n;
309 			continue;
310 		}
311 		if (qtype == T_PTR && type == T_CNAME) {
312 			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
313 			if (n < 0 || !res_dnok(tbuf)) {
314 				had_error++;
315 				continue;
316 			}
317 			cp += n;
318 			if (cp != erdata) {
319 				h_errno = NO_RECOVERY;
320 				return NULL;
321 			}
322 			/* Get canonical name. */
323 			n = strlen(tbuf) + 1;	/* for the \0 */
324 			if (n > ep - bp || n >= MAXHOSTNAMELEN) {
325 				had_error++;
326 				continue;
327 			}
328 			strlcpy(bp, tbuf, (size_t)(ep - bp));
329 			tname = bp;
330 			bp += n;
331 			continue;
332 		}
333 		if (type != qtype) {
334 			if (type != T_KEY && type != T_SIG)
335 				syslog(LOG_NOTICE|LOG_AUTH,
336 	       "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
337 				       qname, p_class(C_IN), p_type(qtype),
338 				       p_type(type));
339 			cp += n;
340 			continue;		/* XXX - had_error++ ? */
341 		}
342 		switch (type) {
343 		case T_PTR:
344 			if (strcasecmp(tname, bp) != 0) {
345 				syslog(LOG_NOTICE|LOG_AUTH,
346 				       AskedForGot, qname, bp);
347 				cp += n;
348 				continue;	/* XXX - had_error++ ? */
349 			}
350 			n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
351 			if ((n < 0) || !res_hnok(bp)) {
352 				had_error++;
353 				break;
354 			}
355 #if MULTI_PTRS_ARE_ALIASES
356 			cp += n;
357 			if (cp != erdata) {
358 				h_errno = NO_RECOVERY;
359 				return NULL;
360 			}
361 			if (!haveanswer)
362 				rs->host.h_name = bp;
363 			else if (ap < &rs->host_aliases[MAXALIASES-1])
364 				*ap++ = bp;
365 			else
366 				n = -1;
367 			if (n != -1) {
368 				n = strlen(bp) + 1;	/* for the \0 */
369 				if (n >= MAXHOSTNAMELEN) {
370 					had_error++;
371 					break;
372 				}
373 				bp += n;
374 			}
375 			break;
376 #else
377 			rs->host.h_name = bp;
378 			if (res->options & RES_USE_INET6) {
379 				n = strlen(bp) + 1;	/* for the \0 */
380 				if (n >= MAXHOSTNAMELEN) {
381 					had_error++;
382 					break;
383 				}
384 				bp += n;
385 				map_v4v6_hostent(&rs->host, &bp, ep);
386 			}
387 			h_errno = NETDB_SUCCESS;
388 			return &rs->host;
389 #endif
390 		case T_A:
391 		case T_AAAA:
392 			if (strcasecmp(rs->host.h_name, bp) != 0) {
393 				syslog(LOG_NOTICE|LOG_AUTH,
394 				       AskedForGot, rs->host.h_name, bp);
395 				cp += n;
396 				continue;	/* XXX - had_error++ ? */
397 			}
398 			if (n != rs->host.h_length) {
399 				cp += n;
400 				continue;
401 			}
402 			if (type == T_AAAA) {
403 				struct in6_addr in6;
404 				memcpy(&in6, cp, IN6ADDRSZ);
405 				if (IN6_IS_ADDR_V4MAPPED(&in6)) {
406 					cp += n;
407 					continue;
408 				}
409 			}
410 			if (!haveanswer) {
411 				int nn;
412 
413 				rs->host.h_name = bp;
414 				nn = strlen(bp) + 1;	/* for the \0 */
415 				bp += nn;
416 			}
417 
418 			bp += sizeof(align) -
419 			    (size_t)((u_long)bp % sizeof(align));
420 
421 			if (bp + n >= &rs->hostbuf[sizeof rs->hostbuf]) {
422 				dprintf("size (%d) too big\n", res, n);
423 				had_error++;
424 				continue;
425 			}
426 			if (hap >= &rs->h_addr_ptrs[MAXADDRS-1]) {
427 				if (!toobig++)
428 					dprintf("Too many addresses (%d)\n",
429 						res, MAXADDRS);
430 				cp += n;
431 				continue;
432 			}
433 			(void)memcpy(*hap++ = bp, cp, (size_t)n);
434 			bp += n;
435 			cp += n;
436 			if (cp != erdata) {
437 				h_errno = NO_RECOVERY;
438 				return NULL;
439 			}
440 			break;
441 		default:
442 			abort();
443 		}
444 		if (!had_error)
445 			haveanswer++;
446 	}
447 	if (haveanswer) {
448 		*ap = NULL;
449 		*hap = NULL;
450 		/*
451 		 * Note: we sort even if host can take only one address
452 		 * in its return structures - should give it the "best"
453 		 * address in that case, not some random one
454 		 */
455 		if (res->nsort && haveanswer > 1 && qtype == T_A)
456 			addrsort(rs->h_addr_ptrs, haveanswer, res);
457 		if (!rs->host.h_name) {
458 			n = strlen(qname) + 1;	/* for the \0 */
459 			if (n > ep - bp || n >= MAXHOSTNAMELEN)
460 				goto no_recovery;
461 			strlcpy(bp, qname, (size_t)(ep - bp));
462 			rs->host.h_name = bp;
463 			bp += n;
464 		}
465 		if (res->options & RES_USE_INET6)
466 			map_v4v6_hostent(&rs->host, &bp, ep);
467 		h_errno = NETDB_SUCCESS;
468 		return &rs->host;
469 	}
470  no_recovery:
471 	h_errno = NO_RECOVERY;
472 	return NULL;
473 }
474 
475 int
gethostbyname_r(const char * name,struct hostent * hp,char * buf,size_t buflen,struct hostent ** result,int * errorp)476 gethostbyname_r(const char *name, struct hostent *hp, char *buf, size_t buflen,
477     struct hostent**result, int *errorp)
478 {
479         struct hostent *res;
480 
481         res = gethostbyname(name);
482         *errorp = h_errno;
483         if (res == NULL) {
484                 *result = NULL;
485                 return -1;
486         }
487         memcpy(hp, res, sizeof *hp);
488         *result = hp;
489         return 0;
490 }
491 
492 struct hostent *
gethostbyname(const char * name)493 gethostbyname(const char *name)
494 {
495 	struct hostent *hp;
496 	res_state res = __res_get_state();
497 
498 	if (res == NULL)
499 		return NULL;
500 
501 	assert(name != NULL);
502 
503 	/* try IPv6 first - if that fails do IPv4 */
504 	if (res->options & RES_USE_INET6) {
505 		hp = gethostbyname_internal(name, AF_INET6, res, NETID_UNSET, MARK_UNSET);
506 		if (hp) {
507 			__res_put_state(res);
508 			return hp;
509 		}
510 	}
511 	hp = gethostbyname_internal(name, AF_INET, res, NETID_UNSET, MARK_UNSET);
512 	__res_put_state(res);
513 	return hp;
514 }
515 
516 struct hostent *
gethostbyname2(const char * name,int af)517 gethostbyname2(const char *name, int af)
518 {
519 	return android_gethostbynamefornet(name, af, NETID_UNSET, MARK_UNSET);
520 }
521 
522 struct hostent *
android_gethostbynamefornet(const char * name,int af,unsigned netid,unsigned mark)523 android_gethostbynamefornet(const char *name, int af, unsigned netid, unsigned mark)
524 {
525 	struct hostent *hp;
526 	res_state res = __res_get_state();
527 
528 	if (res == NULL)
529 		return NULL;
530 	hp = gethostbyname_internal(name, af, res, netid, mark);
531 	__res_put_state(res);
532 	return hp;
533 }
534 
535 
android_open_proxy()536 static FILE* android_open_proxy()
537 {
538 	int sock;
539 	const int one = 1;
540 	struct sockaddr_un proxy_addr;
541 
542 	sock = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
543 	if (sock < 0) {
544 		return NULL;
545 	}
546 
547 	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
548 	memset(&proxy_addr, 0, sizeof(proxy_addr));
549 	proxy_addr.sun_family = AF_UNIX;
550 	strlcpy(proxy_addr.sun_path, "/dev/socket/dnsproxyd", sizeof(proxy_addr.sun_path));
551 	if (TEMP_FAILURE_RETRY(connect(sock,
552 			(const struct sockaddr*) &proxy_addr,
553 			sizeof(proxy_addr))) != 0) {
554 		close(sock);
555 		return NULL;
556 	}
557 
558 	return fdopen(sock, "r+");
559 }
560 
561 static struct hostent *
android_read_hostent(FILE * proxy)562 android_read_hostent(FILE* proxy)
563 {
564 	uint32_t size;
565 	char buf[4];
566 	if (fread(buf, 1, sizeof(buf), proxy) != sizeof(buf)) return NULL;
567 
568 	/* This is reading serialized data from system/netd/server/DnsProxyListener.cpp
569 	 * and changes here need to be matched there */
570 	int result_code = strtol(buf, NULL, 10);
571 	if (result_code != DnsProxyQueryResult) {
572 		fread(&size, 1, sizeof(size), proxy);
573 		return NULL;
574 	}
575 
576 	if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL;
577 	size = ntohl(size);
578 	res_static rs = __res_get_static();
579 	memset(&rs->host, 0, sizeof(rs->host));
580 	char *ptr = rs->hostbuf;
581 
582 	if (fread(ptr, 1, size, proxy) != size) return NULL;
583 	ptr += size;
584 	rs->host.h_name = rs->hostbuf;
585 
586 	char **aliases = rs->host_aliases;
587 	rs->host.h_aliases = rs->host_aliases;
588 	while (1) {
589 		if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL;
590 		size = ntohl(size);
591 
592 		if (size == 0) {
593 			*aliases = NULL;
594 			break;
595 		}
596 		if (fread(ptr, 1, size, proxy) != size) return NULL;
597 		*aliases++ = ptr;
598 		ptr += size;
599 	}
600 
601 	if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL;
602 	rs->host.h_addrtype = ntohl(size);
603 
604 	if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL;
605 	rs->host.h_length = ntohl(size);
606 
607 	char **addrs = rs->h_addr_ptrs;
608 	rs->host.h_addr_list = rs->h_addr_ptrs;
609 	while (1) {
610 		if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL;
611 		size = ntohl(size);
612 		if (size == 0) {
613 			*addrs = NULL;
614 			break;
615 		}
616 		if (fread(ptr, 1, size, proxy) != size) return NULL;
617 		*addrs++ = ptr;
618 		ptr += size;
619 	}
620 
621 	return &rs->host;
622 }
623 
624 
625 static struct hostent *
gethostbyname_internal_real(const char * name,int af,res_state res)626 gethostbyname_internal_real(const char *name, int af, res_state res)
627 {
628 	const char *cp;
629 	char *bp, *ep;
630 	int size;
631 	struct hostent *hp;
632 	res_static rs = __res_get_static();
633 
634 	static const ns_dtab dtab[] = {
635 		NS_FILES_CB(_gethtbyname, NULL)
636 		{ NSSRC_DNS, _dns_gethtbyname, NULL },	/* force -DHESIOD */
637 		{ 0, 0, 0 }
638 	};
639 
640 	assert(name != NULL);
641 
642 	switch (af) {
643 	case AF_INET:
644 		size = INADDRSZ;
645 		break;
646 	case AF_INET6:
647 		size = IN6ADDRSZ;
648 		break;
649 	default:
650 		h_errno = NETDB_INTERNAL;
651 		errno = EAFNOSUPPORT;
652 		return NULL;
653 	}
654 
655 	rs->host.h_addrtype = af;
656 	rs->host.h_length = size;
657 
658 	/*
659 	 * if there aren't any dots, it could be a user-level alias.
660 	 * this is also done in res_nquery() since we are not the only
661 	 * function that looks up host names.
662 	 */
663 	if (!strchr(name, '.') && (cp = __hostalias(name)))
664 		name = cp;
665 
666 	/*
667 	 * disallow names consisting only of digits/dots, unless
668 	 * they end in a dot.
669 	 */
670 	if (isdigit((u_char) name[0]))
671 		for (cp = name;; ++cp) {
672 			if (!*cp) {
673 				if (*--cp == '.')
674 					break;
675 				/*
676 				 * All-numeric, no dot at the end.
677 				 * Fake up a hostent as if we'd actually
678 				 * done a lookup.
679 				 */
680 				if (inet_pton(af, name,
681 				    (char *)(void *)rs->host_addr) <= 0) {
682 					h_errno = HOST_NOT_FOUND;
683 					return NULL;
684 				}
685 				strncpy(rs->hostbuf, name, MAXDNAME);
686 				rs->hostbuf[MAXDNAME] = '\0';
687 				bp = rs->hostbuf + MAXDNAME;
688 				ep = rs->hostbuf + sizeof rs->hostbuf;
689 				rs->host.h_name = rs->hostbuf;
690 				rs->host.h_aliases = rs->host_aliases;
691 				rs->host_aliases[0] = NULL;
692 				rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr;
693 				rs->h_addr_ptrs[1] = NULL;
694 				rs->host.h_addr_list = rs->h_addr_ptrs;
695 				if (res->options & RES_USE_INET6)
696 					map_v4v6_hostent(&rs->host, &bp, ep);
697 				h_errno = NETDB_SUCCESS;
698 				return &rs->host;
699 			}
700 			if (!isdigit((u_char) *cp) && *cp != '.')
701 				break;
702 		}
703 	if ((isxdigit((u_char) name[0]) && strchr(name, ':') != NULL) ||
704 	    name[0] == ':')
705 		for (cp = name;; ++cp) {
706 			if (!*cp) {
707 				if (*--cp == '.')
708 					break;
709 				/*
710 				 * All-IPv6-legal, no dot at the end.
711 				 * Fake up a hostent as if we'd actually
712 				 * done a lookup.
713 				 */
714 				if (inet_pton(af, name,
715 				    (char *)(void *)rs->host_addr) <= 0) {
716 					h_errno = HOST_NOT_FOUND;
717 					return NULL;
718 				}
719 				strncpy(rs->hostbuf, name, MAXDNAME);
720 				rs->hostbuf[MAXDNAME] = '\0';
721 				bp = rs->hostbuf + MAXDNAME;
722 				ep = rs->hostbuf + sizeof rs->hostbuf;
723 				rs->host.h_name = rs->hostbuf;
724 				rs->host.h_aliases = rs->host_aliases;
725 				rs->host_aliases[0] = NULL;
726 				rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr;
727 				rs->h_addr_ptrs[1] = NULL;
728 				rs->host.h_addr_list = rs->h_addr_ptrs;
729 				h_errno = NETDB_SUCCESS;
730 				return &rs->host;
731 			}
732 			if (!isxdigit((u_char) *cp) && *cp != ':' && *cp != '.')
733 				break;
734 		}
735 
736 	hp = NULL;
737 	h_errno = NETDB_INTERNAL;
738 	if (nsdispatch(&hp, dtab, NSDB_HOSTS, "gethostbyname",
739 	    default_dns_files, name, strlen(name), af) != NS_SUCCESS) {
740 		return NULL;
741 	}
742 	h_errno = NETDB_SUCCESS;
743 	return hp;
744 }
745 
746 
747 // very similar in proxy-ness to android_getaddrinfo_proxy
748 static struct hostent *
gethostbyname_internal(const char * name,int af,res_state res,unsigned netid,unsigned mark)749 gethostbyname_internal(const char *name, int af, res_state res, unsigned netid, unsigned mark)
750 {
751 	const char *cache_mode = getenv("ANDROID_DNS_MODE");
752 	FILE* proxy = NULL;
753 	struct hostent *result = NULL;
754 
755 	if (cache_mode != NULL && strcmp(cache_mode, "local") == 0) {
756 		res_setnetid(res, netid);
757 		res_setmark(res, mark);
758 		return gethostbyname_internal_real(name, af, res);
759 	}
760 
761 	proxy = android_open_proxy();
762 	if (proxy == NULL) goto exit;
763 
764 	netid = __netdClientDispatch.netIdForResolv(netid);
765 
766 	/* This is writing to system/netd/server/DnsProxyListener.cpp and changes
767 	 * here need to be matched there */
768 	if (fprintf(proxy, "gethostbyname %u %s %d",
769 			netid,
770 			name == NULL ? "^" : name,
771 			af) < 0) {
772 		goto exit;
773 	}
774 
775 	if (fputc(0, proxy) == EOF || fflush(proxy) != 0) {
776 		goto exit;
777 	}
778 
779 	result = android_read_hostent(proxy);
780 
781 exit:
782 	if (proxy != NULL) {
783 		fclose(proxy);
784 	}
785 	return result;
786 }
787 
788 
789 struct hostent *
android_gethostbyaddrfornet_proxy(const void * addr,socklen_t len,int af,unsigned netid)790 android_gethostbyaddrfornet_proxy(const void *addr,
791     socklen_t len, int af, unsigned netid)
792 {
793 	struct hostent *result = NULL;
794 	FILE* proxy = android_open_proxy();
795 
796 	if (proxy == NULL) goto exit;
797 
798 	char buf[INET6_ADDRSTRLEN];  //big enough for IPv4 and IPv6
799 	const char * addrStr = inet_ntop(af, addr, buf, sizeof(buf));
800 	if (addrStr == NULL) goto exit;
801 
802 	netid = __netdClientDispatch.netIdForResolv(netid);
803 
804 	if (fprintf(proxy, "gethostbyaddr %s %d %d %u",
805 			addrStr, len, af, netid) < 0) {
806 		goto exit;
807 	}
808 
809 	if (fputc(0, proxy) == EOF || fflush(proxy) != 0) {
810 		goto exit;
811 	}
812 
813 	result = android_read_hostent(proxy);
814 exit:
815 	if (proxy != NULL) {
816 		fclose(proxy);
817 	}
818 	return result;
819 }
820 
821 struct hostent *
android_gethostbyaddrfornet_real(const void * addr,socklen_t len,int af,unsigned netid,unsigned mark)822 android_gethostbyaddrfornet_real(const void *addr,
823     socklen_t len, int af, unsigned netid, unsigned mark)
824 {
825 	const u_char *uaddr = (const u_char *)addr;
826 	socklen_t size;
827 	struct hostent *hp;
828 	static const ns_dtab dtab[] = {
829 		NS_FILES_CB(_gethtbyaddr, NULL)
830 		{ NSSRC_DNS, _dns_gethtbyaddr, NULL },	/* force -DHESIOD */
831 		{ 0, 0, 0 }
832 	};
833 
834 	assert(addr != NULL);
835 
836 	if (af == AF_INET6 && len == NS_IN6ADDRSZ &&
837 	    (IN6_IS_ADDR_LINKLOCAL((const struct in6_addr *)addr) ||
838 	     IN6_IS_ADDR_SITELOCAL((const struct in6_addr *)addr))) {
839 		h_errno = HOST_NOT_FOUND;
840 		return NULL;
841 	}
842 	if (af == AF_INET6 && len == NS_IN6ADDRSZ &&
843 	    (IN6_IS_ADDR_V4MAPPED((const struct in6_addr *)addr) ||
844 	     IN6_IS_ADDR_V4COMPAT((const struct in6_addr *)addr))) {
845 		/* Unmap. */
846 		uaddr += NS_IN6ADDRSZ - NS_INADDRSZ;
847 		addr = uaddr;
848 		af = AF_INET;
849 		len = NS_INADDRSZ;
850 	}
851 	switch (af) {
852 	case AF_INET:
853 		size = NS_INADDRSZ;
854 		break;
855 	case AF_INET6:
856 		size = NS_IN6ADDRSZ;
857 		break;
858 	default:
859 		errno = EAFNOSUPPORT;
860 		h_errno = NETDB_INTERNAL;
861 		return NULL;
862 	}
863 	if (size != len) {
864 		errno = EINVAL;
865 		h_errno = NETDB_INTERNAL;
866 		return NULL;
867 	}
868 	hp = NULL;
869 	h_errno = NETDB_INTERNAL;
870 	if (nsdispatch(&hp, dtab, NSDB_HOSTS, "gethostbyaddr",
871 		default_dns_files, uaddr, len, af, netid, mark) != NS_SUCCESS)
872 		return NULL;
873 	h_errno = NETDB_SUCCESS;
874 	return hp;
875 }
876 
877 struct hostent *
android_gethostbyaddrfornet(const void * addr,socklen_t len,int af,unsigned netid,unsigned mark)878 android_gethostbyaddrfornet(const void *addr, socklen_t len, int af, unsigned netid, unsigned mark)
879 {
880 	const char *cache_mode = getenv("ANDROID_DNS_MODE");
881 
882 	if (cache_mode == NULL || strcmp(cache_mode, "local") != 0) {
883 		return android_gethostbyaddrfornet_proxy(addr, len, af, netid);
884 	} else {
885 		return android_gethostbyaddrfornet_real(addr,len, af, netid, mark);
886 	}
887 }
888 
889 struct hostent *
gethostbyaddr(const void * addr,socklen_t len,int af)890 gethostbyaddr(const void *addr, socklen_t len, int af)
891 {
892 	return android_gethostbyaddrfornet(addr, len, af, NETID_UNSET, MARK_UNSET);
893 }
894 
895 
896 static void
_sethtent(int f)897 _sethtent(int f)
898 {
899     res_static  rs = __res_get_static();
900     if (rs == NULL) return;
901 	if (!rs->hostf)
902 		rs->hostf = fopen(_PATH_HOSTS, "r" );
903 	else
904 		rewind(rs->hostf);
905 	rs->stayopen = f;
906 }
907 
908 static void
_endhtent(void)909 _endhtent(void)
910 {
911     res_static  rs = __res_get_static();
912     if (rs == NULL) return;
913 
914 	if (rs->hostf && !rs->stayopen) {
915 		(void) fclose(rs->hostf);
916 		rs->hostf = NULL;
917 	}
918 }
919 
920 static struct hostent *
_gethtent(void)921 _gethtent(void)
922 {
923 	char *p;
924 	char *cp, **q;
925 	int af, len;
926 	res_static  rs = __res_get_static();
927 
928 	if (!rs->hostf && !(rs->hostf = fopen(_PATH_HOSTS, "r" ))) {
929 		h_errno = NETDB_INTERNAL;
930 		return NULL;
931 	}
932  again:
933 	if (!(p = fgets(rs->hostbuf, sizeof rs->hostbuf, rs->hostf))) {
934 		h_errno = HOST_NOT_FOUND;
935 		return NULL;
936 	}
937 	if (*p == '#')
938 		goto again;
939 	if (!(cp = strpbrk(p, "#\n")))
940 		goto again;
941 	*cp = '\0';
942 	if (!(cp = strpbrk(p, " \t")))
943 		goto again;
944 	*cp++ = '\0';
945 	if (inet_pton(AF_INET6, p, (char *)(void *)rs->host_addr) > 0) {
946 		af = AF_INET6;
947 		len = IN6ADDRSZ;
948 	} else if (inet_pton(AF_INET, p, (char *)(void *)rs->host_addr) > 0) {
949 		res_state res = __res_get_state();
950 		if (res == NULL)
951 			return NULL;
952 		if (res->options & RES_USE_INET6) {
953 			map_v4v6_address((char *)(void *)rs->host_addr,
954 			    (char *)(void *)rs->host_addr);
955 			af = AF_INET6;
956 			len = IN6ADDRSZ;
957 		} else {
958 			af = AF_INET;
959 			len = INADDRSZ;
960 		}
961 		__res_put_state(res);
962 	} else {
963 		goto again;
964 	}
965 	/* if this is not something we're looking for, skip it. */
966 	if (rs->host.h_addrtype != 0 && rs->host.h_addrtype != af)
967 		goto again;
968 	if (rs->host.h_length != 0 && rs->host.h_length != len)
969 		goto again;
970 	rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr;
971 	rs->h_addr_ptrs[1] = NULL;
972 	rs->host.h_addr_list = rs->h_addr_ptrs;
973 	rs->host.h_length = len;
974 	rs->host.h_addrtype = af;
975 	while (*cp == ' ' || *cp == '\t')
976 		cp++;
977 	rs->host.h_name = cp;
978 	q = rs->host.h_aliases = rs->host_aliases;
979 	if ((cp = strpbrk(cp, " \t")) != NULL)
980 		*cp++ = '\0';
981 	while (cp && *cp) {
982 		if (*cp == ' ' || *cp == '\t') {
983 			cp++;
984 			continue;
985 		}
986 		if (q < &rs->host_aliases[MAXALIASES - 1])
987 			*q++ = cp;
988 		if ((cp = strpbrk(cp, " \t")) != NULL)
989 			*cp++ = '\0';
990 	}
991 	*q = NULL;
992 	h_errno = NETDB_SUCCESS;
993 	return &rs->host;
994 }
995 
996 /*ARGSUSED*/
997 int
_gethtbyname(void * rv,void * cb_data,va_list ap)998 _gethtbyname(void *rv, void *cb_data, va_list ap)
999 {
1000 	struct hostent *hp;
1001 	const char *name;
1002 	int af;
1003 
1004 	assert(rv != NULL);
1005 
1006 	name = va_arg(ap, char *);
1007 	/* NOSTRICT skip len */(void)va_arg(ap, int);
1008 	af = va_arg(ap, int);
1009 
1010 	hp = NULL;
1011 #if 0
1012 	{
1013 		res_state res = __res_get_state();
1014 		if (res == NULL)
1015 			return NS_NOTFOUND;
1016 		if (res->options & RES_USE_INET6)
1017 			hp = _gethtbyname2(name, AF_INET6);
1018 		if (hp==NULL)
1019 			hp = _gethtbyname2(name, AF_INET);
1020 		__res_put_state(res);
1021 	}
1022 #else
1023 	hp = _gethtbyname2(name, af);
1024 #endif
1025 	*((struct hostent **)rv) = hp;
1026 	if (hp == NULL) {
1027 		h_errno = HOST_NOT_FOUND;
1028 		return NS_NOTFOUND;
1029 	}
1030 	return NS_SUCCESS;
1031 }
1032 
1033 static struct hostent *
_gethtbyname2(const char * name,int af)1034 _gethtbyname2(const char *name, int af)
1035 {
1036 	struct hostent *p;
1037 	char *tmpbuf, *ptr, **cp;
1038 	int num;
1039 	size_t len;
1040 	res_static rs = __res_get_static();
1041 
1042 	assert(name != NULL);
1043 
1044 	_sethtent(rs->stayopen);
1045 	ptr = tmpbuf = NULL;
1046 	num = 0;
1047 	while ((p = _gethtent()) != NULL && num < MAXADDRS) {
1048 		if (p->h_addrtype != af)
1049 			continue;
1050 		if (strcasecmp(p->h_name, name) != 0) {
1051 			for (cp = p->h_aliases; *cp != NULL; cp++)
1052 				if (strcasecmp(*cp, name) == 0)
1053 					break;
1054 			if (*cp == NULL) continue;
1055 		}
1056 
1057 		if (num == 0) {
1058 			size_t bufsize;
1059 			char *src;
1060 
1061 			bufsize = strlen(p->h_name) + 2 +
1062 				  MAXADDRS * p->h_length +
1063 				  ALIGNBYTES;
1064 			for (cp = p->h_aliases; *cp != NULL; cp++)
1065 				bufsize += strlen(*cp) + 1;
1066 
1067 			if ((tmpbuf = malloc(bufsize)) == NULL) {
1068 				h_errno = NETDB_INTERNAL;
1069 				return NULL;
1070 			}
1071 
1072 			ptr = tmpbuf;
1073 			src = p->h_name;
1074 			while ((*ptr++ = *src++) != '\0');
1075 			for (cp = p->h_aliases; *cp != NULL; cp++) {
1076 				src = *cp;
1077 				while ((*ptr++ = *src++) != '\0');
1078 			}
1079 			*ptr++ = '\0';
1080 
1081 			ptr = (char *)(void *)ALIGN(ptr);
1082 		}
1083 
1084 		(void)memcpy(ptr, p->h_addr_list[0], (size_t)p->h_length);
1085 		ptr += p->h_length;
1086 		num++;
1087 	}
1088 	_endhtent();
1089 	if (num == 0) return NULL;
1090 
1091 	len = ptr - tmpbuf;
1092 	if (len > (sizeof(rs->hostbuf) - ALIGNBYTES)) {
1093 		free(tmpbuf);
1094 		errno = ENOSPC;
1095 		h_errno = NETDB_INTERNAL;
1096 		return NULL;
1097 	}
1098 	ptr = memcpy((void *)ALIGN(rs->hostbuf), tmpbuf, len);
1099 	free(tmpbuf);
1100 
1101 	rs->host.h_name = ptr;
1102 	while (*ptr++);
1103 
1104 	cp = rs->host_aliases;
1105 	while (*ptr) {
1106 		*cp++ = ptr;
1107 		while (*ptr++);
1108 	}
1109 	ptr++;
1110 	*cp = NULL;
1111 
1112 	ptr = (char *)(void *)ALIGN(ptr);
1113 	cp = rs->h_addr_ptrs;
1114 	while (num--) {
1115 		*cp++ = ptr;
1116 		ptr += rs->host.h_length;
1117 	}
1118 	*cp = NULL;
1119 
1120 	return &rs->host;
1121 }
1122 
1123 /*ARGSUSED*/
1124 static int
_gethtbyaddr(void * rv,void * cb_data,va_list ap)1125 _gethtbyaddr(void *rv, void *cb_data, va_list ap)
1126 {
1127 	struct hostent *p;
1128 	const unsigned char *addr;
1129 	int len, af;
1130 	res_static  rs = __res_get_static();
1131 
1132 	assert(rv != NULL);
1133 
1134 	addr = va_arg(ap, unsigned char *);
1135 	len = va_arg(ap, int);
1136 	af = va_arg(ap, int);
1137 
1138 	rs->host.h_length = len;
1139 	rs->host.h_addrtype = af;
1140 
1141 	_sethtent(rs->stayopen);
1142 	while ((p = _gethtent()) != NULL)
1143 		if (p->h_addrtype == af && !memcmp(p->h_addr, addr,
1144 		    (size_t)len))
1145 			break;
1146 	_endhtent();
1147 	*((struct hostent **)rv) = p;
1148 	if (p==NULL) {
1149 		h_errno = HOST_NOT_FOUND;
1150 		return NS_NOTFOUND;
1151 	}
1152 	return NS_SUCCESS;
1153 }
1154 
1155 static void
map_v4v6_address(const char * src,char * dst)1156 map_v4v6_address(const char *src, char *dst)
1157 {
1158 	u_char *p = (u_char *)dst;
1159 	char tmp[INADDRSZ];
1160 	int i;
1161 
1162 	assert(src != NULL);
1163 	assert(dst != NULL);
1164 
1165 	/* Stash a temporary copy so our caller can update in place. */
1166 	(void)memcpy(tmp, src, INADDRSZ);
1167 	/* Mark this ipv6 addr as a mapped ipv4. */
1168 	for (i = 0; i < 10; i++)
1169 		*p++ = 0x00;
1170 	*p++ = 0xff;
1171 	*p++ = 0xff;
1172 	/* Retrieve the saved copy and we're done. */
1173 	(void)memcpy((void *)p, tmp, INADDRSZ);
1174 }
1175 
1176 static void
map_v4v6_hostent(struct hostent * hp,char ** bpp,char * ep)1177 map_v4v6_hostent(struct hostent *hp, char **bpp, char *ep)
1178 {
1179 	char **ap;
1180 
1181 	assert(hp != NULL);
1182 	assert(bpp != NULL);
1183 	assert(ep != NULL);
1184 
1185 	if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
1186 		return;
1187 	hp->h_addrtype = AF_INET6;
1188 	hp->h_length = IN6ADDRSZ;
1189 	for (ap = hp->h_addr_list; *ap; ap++) {
1190 		int i = sizeof(align) - (size_t)((u_long)*bpp % sizeof(align));
1191 
1192 		if (ep - *bpp < (i + IN6ADDRSZ)) {
1193 			/* Out of memory.  Truncate address list here.  XXX */
1194 			*ap = NULL;
1195 			return;
1196 		}
1197 		*bpp += i;
1198 		map_v4v6_address(*ap, *bpp);
1199 		*ap = *bpp;
1200 		*bpp += IN6ADDRSZ;
1201 	}
1202 }
1203 
1204 static void
addrsort(char ** ap,int num,res_state res)1205 addrsort(char **ap, int num, res_state res)
1206 {
1207 	int i, j;
1208 	char **p;
1209 	short aval[MAXADDRS];
1210 	int needsort = 0;
1211 
1212 	assert(ap != NULL);
1213 
1214 	p = ap;
1215 	for (i = 0; i < num; i++, p++) {
1216 	    for (j = 0 ; (unsigned)j < res->nsort; j++)
1217 		if (res->sort_list[j].addr.s_addr ==
1218 		    (((struct in_addr *)(void *)(*p))->s_addr &
1219 		    res->sort_list[j].mask))
1220 			break;
1221 	    aval[i] = j;
1222 	    if (needsort == 0 && i > 0 && j < aval[i-1])
1223 		needsort = i;
1224 	}
1225 	if (!needsort)
1226 	    return;
1227 
1228 	while (needsort < num) {
1229 	    for (j = needsort - 1; j >= 0; j--) {
1230 		if (aval[j] > aval[j+1]) {
1231 		    char *hp;
1232 
1233 		    i = aval[j];
1234 		    aval[j] = aval[j+1];
1235 		    aval[j+1] = i;
1236 
1237 		    hp = ap[j];
1238 		    ap[j] = ap[j+1];
1239 		    ap[j+1] = hp;
1240 		} else
1241 		    break;
1242 	    }
1243 	    needsort++;
1244 	}
1245 }
1246 
1247 struct hostent *
gethostent(void)1248 gethostent(void)
1249 {
1250     res_static  rs = __res_get_static();
1251 	rs->host.h_addrtype = 0;
1252 	rs->host.h_length = 0;
1253 	return _gethtent();
1254 }
1255 
1256 /*ARGSUSED*/
1257 static int
_dns_gethtbyname(void * rv,void * cb_data,va_list ap)1258 _dns_gethtbyname(void *rv, void *cb_data, va_list ap)
1259 {
1260 	querybuf *buf;
1261 	int n, type;
1262 	struct hostent *hp;
1263 	const char *name;
1264 	int af;
1265 	res_state res;
1266 
1267 	assert(rv != NULL);
1268 
1269 	name = va_arg(ap, char *);
1270 	/* NOSTRICT skip len */(void)va_arg(ap, int);
1271 	af = va_arg(ap, int);
1272 
1273 	switch (af) {
1274 	case AF_INET:
1275 		type = T_A;
1276 		break;
1277 	case AF_INET6:
1278 		type = T_AAAA;
1279 		break;
1280 	default:
1281 		return NS_UNAVAIL;
1282 	}
1283 	buf = malloc(sizeof(*buf));
1284 	if (buf == NULL) {
1285 		h_errno = NETDB_INTERNAL;
1286 		return NS_NOTFOUND;
1287 	}
1288 	res = __res_get_state();
1289 	if (res == NULL) {
1290 		free(buf);
1291 		return NS_NOTFOUND;
1292 	}
1293 	n = res_nsearch(res, name, C_IN, type, buf->buf, sizeof(buf->buf));
1294 	if (n < 0) {
1295 		free(buf);
1296 		dprintf("res_nsearch failed (%d)\n", res, n);
1297 		__res_put_state(res);
1298 		return NS_NOTFOUND;
1299 	}
1300 	hp = getanswer(buf, n, name, type, res);
1301 	free(buf);
1302 	__res_put_state(res);
1303 	if (hp == NULL)
1304 		switch (h_errno) {
1305 		case HOST_NOT_FOUND:
1306 			return NS_NOTFOUND;
1307 		case TRY_AGAIN:
1308 			return NS_TRYAGAIN;
1309 		default:
1310 			return NS_UNAVAIL;
1311 		}
1312 	*((struct hostent **)rv) = hp;
1313 	return NS_SUCCESS;
1314 }
1315 
1316 /*ARGSUSED*/
1317 static int
_dns_gethtbyaddr(void * rv,void * cb_data,va_list ap)1318 _dns_gethtbyaddr(void *rv, void	*cb_data, va_list ap)
1319 {
1320 	char qbuf[MAXDNAME + 1], *qp, *ep;
1321 	int n;
1322 	querybuf *buf;
1323 	struct hostent *hp;
1324 	const unsigned char *uaddr;
1325 	int len, af, advance;
1326 	res_state res;
1327 	unsigned netid, mark;
1328 	res_static rs = __res_get_static();
1329 
1330 	assert(rv != NULL);
1331 
1332 	uaddr = va_arg(ap, unsigned char *);
1333 	len = va_arg(ap, int);
1334 	af = va_arg(ap, int);
1335 	netid = va_arg(ap, unsigned);
1336 	mark = va_arg(ap, unsigned);
1337 
1338 	switch (af) {
1339 	case AF_INET:
1340 		(void)snprintf(qbuf, sizeof(qbuf), "%u.%u.%u.%u.in-addr.arpa",
1341 		    (uaddr[3] & 0xff), (uaddr[2] & 0xff),
1342 		    (uaddr[1] & 0xff), (uaddr[0] & 0xff));
1343 		break;
1344 
1345 	case AF_INET6:
1346 		qp = qbuf;
1347 		ep = qbuf + sizeof(qbuf) - 1;
1348 		for (n = IN6ADDRSZ - 1; n >= 0; n--) {
1349 			advance = snprintf(qp, (size_t)(ep - qp), "%x.%x.",
1350 			    uaddr[n] & 0xf,
1351 			    ((unsigned int)uaddr[n] >> 4) & 0xf);
1352 			if (advance > 0 && qp + advance < ep)
1353 				qp += advance;
1354 			else {
1355 				h_errno = NETDB_INTERNAL;
1356 				return NS_NOTFOUND;
1357 			}
1358 		}
1359 		if (strlcat(qbuf, "ip6.arpa", sizeof(qbuf)) >= sizeof(qbuf)) {
1360 			h_errno = NETDB_INTERNAL;
1361 			return NS_NOTFOUND;
1362 		}
1363 		break;
1364 	default:
1365 		abort();
1366 	}
1367 
1368 	buf = malloc(sizeof(*buf));
1369 	if (buf == NULL) {
1370 		h_errno = NETDB_INTERNAL;
1371 		return NS_NOTFOUND;
1372 	}
1373 	res = __res_get_state();
1374 	if (res == NULL) {
1375 		free(buf);
1376 		return NS_NOTFOUND;
1377 	}
1378 	res_setnetid(res, netid);
1379 	res_setmark(res, mark);
1380 	n = res_nquery(res, qbuf, C_IN, T_PTR, buf->buf, sizeof(buf->buf));
1381 	if (n < 0) {
1382 		free(buf);
1383 		dprintf("res_nquery failed (%d)\n", res, n);
1384 		__res_put_state(res);
1385 		return NS_NOTFOUND;
1386 	}
1387 	hp = getanswer(buf, n, qbuf, T_PTR, res);
1388 	free(buf);
1389 	if (hp == NULL) {
1390 		__res_put_state(res);
1391 		switch (h_errno) {
1392 		case HOST_NOT_FOUND:
1393 			return NS_NOTFOUND;
1394 		case TRY_AGAIN:
1395 			return NS_TRYAGAIN;
1396 		default:
1397 			return NS_UNAVAIL;
1398 		}
1399 	}
1400 	hp->h_addrtype = af;
1401 	hp->h_length = len;
1402 	(void)memcpy(rs->host_addr, uaddr, (size_t)len);
1403 	rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr;
1404 	rs->h_addr_ptrs[1] = NULL;
1405 	if (af == AF_INET && (res->options & RES_USE_INET6)) {
1406 		map_v4v6_address((char *)(void *)rs->host_addr,
1407 		    (char *)(void *)rs->host_addr);
1408 		hp->h_addrtype = AF_INET6;
1409 		hp->h_length = IN6ADDRSZ;
1410 	}
1411 
1412 	__res_put_state(res);
1413 	*((struct hostent **)rv) = hp;
1414 	h_errno = NETDB_SUCCESS;
1415 	return NS_SUCCESS;
1416 }
1417