getaddrinfo.c revision 62614 
1/*	$FreeBSD: head/lib/libc/net/getaddrinfo.c 62614 2000-07-05 05:07:23Z itojun $	*/
2/*	$KAME: getaddrinfo.c,v 1.10 2000/07/05 02:59:28 itojun Exp $	*/
3
4/*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33/*
34 * "#ifdef FAITH" part is local hack for supporting IPv4-v6 translator.
35 *
36 * Issues to be discussed:
37 * - Thread safe-ness must be checked.
38 * - Return values.  There are nonstandard return values defined and used
39 *   in the source code.  This is because RFC2553 is silent about which error
40 *   code must be returned for which situation.
41 * - freeaddrinfo(NULL).  RFC2553 is silent about it.  XNET 5.2 says it is
42 *   invalid.
43 *   current code - SEGV on freeaddrinfo(NULL)
44 * Note:
45 * - We use getipnodebyname() just for thread-safeness.  There's no intent
46 *   to let it do PF_UNSPEC (actually we never pass PF_UNSPEC to
47 *   getipnodebyname().
48 * - The code filters out AFs that are not supported by the kernel,
49 *   when globbing NULL hostname (to loopback, or wildcard).  Is it the right
50 *   thing to do?  What is the relationship with post-RFC2553 AI_ADDRCONFIG
51 *   in ai_flags?
52 * - (post-2553) semantics of AI_ADDRCONFIG itself is too vague.
53 *   (1) what should we do against numeric hostname (2) what should we do
54 *   against NULL hostname (3) what is AI_ADDRCONFIG itself.  AF not ready?
55 *   non-loopback address configured?  global address configured?
56 * - To avoid search order issue, we have a big amount of code duplicate
57 *   from gethnamaddr.c and some other places.  The issues that there's no
58 *   lower layer function to lookup "IPv4 or IPv6" record.  Calling
59 *   gethostbyname2 from getaddrinfo will end up in wrong search order, as
60 *   follows:
61 *	- The code makes use of following calls when asked to resolver with
62 *	  ai_family  = PF_UNSPEC:
63 *		getipnodebyname(host, AF_INET6);
64 *		getipnodebyname(host, AF_INET);
65 *	  This will result in the following queries if the node is configure to
66 *	  prefer /etc/hosts than DNS:
67 *		lookup /etc/hosts for IPv6 address
68 *		lookup DNS for IPv6 address
69 *		lookup /etc/hosts for IPv4 address
70 *		lookup DNS for IPv4 address
71 *	  which may not meet people's requirement.
72 *	  The right thing to happen is to have underlying layer which does
73 *	  PF_UNSPEC lookup (lookup both) and return chain of addrinfos.
74 *	  This would result in a bit of code duplicate with _dns_ghbyname() and
75 *	  friends.
76 */
77/*
78 * diffs with other KAME platforms:
79 * - other KAME platforms already nuked FAITH ($GAI), but as FreeBSD
80 *   4.0-RELEASE supplies it, we still have the code here.
81 * - EAI_RESNULL support
82 * - AI_ADDRCONFIG support is supplied
83 * - EDNS0 support is not available due to resolver differences
84 * - some of FreeBSD style (#define tabify and others)
85 * - AI_ADDRCONFIG is turned on by default.
86 * - classful IPv4 numeric (127.1) is allowed.
87 */
88
89#include <sys/types.h>
90#include <sys/param.h>
91#include <sys/socket.h>
92#include <net/if.h>
93#include <netinet/in.h>
94#include <arpa/inet.h>
95#include <arpa/nameser.h>
96#include <netdb.h>
97#include <resolv.h>
98#include <string.h>
99#include <stdlib.h>
100#include <stddef.h>
101#include <ctype.h>
102#include <unistd.h>
103#include <stdio.h>
104#include <errno.h>
105
106#if defined(__KAME__) && defined(INET6)
107# define FAITH
108#endif
109
110#define	SUCCESS 0
111#define	ANY 0
112#define	YES 1
113#define	NO  0
114
115static const char in_addrany[] = { 0, 0, 0, 0 };
116static const char in6_addrany[] = {
117	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
118};
119static const char in_loopback[] = { 127, 0, 0, 1 };
120static const char in6_loopback[] = {
121	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
122};
123
124static const struct afd {
125	int a_af;
126	int a_addrlen;
127	int a_socklen;
128	int a_off;
129	const char *a_addrany;
130	const char *a_loopback;
131	int a_scoped;
132} afdl [] = {
133#ifdef INET6
134#define	N_INET6 0
135	{PF_INET6, sizeof(struct in6_addr),
136	 sizeof(struct sockaddr_in6),
137	 offsetof(struct sockaddr_in6, sin6_addr),
138	 in6_addrany, in6_loopback, 1},
139#define	N_INET 1
140#else
141#define	N_INET 0
142#endif
143	{PF_INET, sizeof(struct in_addr),
144	 sizeof(struct sockaddr_in),
145	 offsetof(struct sockaddr_in, sin_addr),
146	 in_addrany, in_loopback, 0},
147	{0, 0, 0, 0, NULL, NULL, 0},
148};
149
150struct explore {
151	int e_af;
152	int e_socktype;
153	int e_protocol;
154	const char *e_protostr;
155	int e_wild;
156#define	WILD_AF(ex)		((ex)->e_wild & 0x01)
157#define	WILD_SOCKTYPE(ex)	((ex)->e_wild & 0x02)
158#define	WILD_PROTOCOL(ex)	((ex)->e_wild & 0x04)
159};
160
161static const struct explore explore[] = {
162#if 0
163	{ PF_LOCAL, 0, ANY, ANY, NULL, 0x01 },
164#endif
165#ifdef INET6
166	{ PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
167	{ PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
168	{ PF_INET6, SOCK_RAW, ANY, NULL, 0x05 },
169#endif
170	{ PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
171	{ PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
172	{ PF_INET, SOCK_RAW, ANY, NULL, 0x05 },
173	{ PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
174	{ PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
175	{ PF_UNSPEC, SOCK_RAW, ANY, NULL, 0x05 },
176	{ -1, 0, 0, NULL, 0 },
177};
178
179#ifdef INET6
180#define	PTON_MAX	16
181#else
182#define	PTON_MAX	4
183#endif
184
185#if PACKETSZ > 1024
186#define MAXPACKET	PACKETSZ
187#else
188#define MAXPACKET	1024
189#endif
190
191typedef union {
192	HEADER hdr;
193	u_char buf[MAXPACKET];
194} querybuf;
195
196struct res_target {
197	struct res_target *next;
198	const char *name;	/* domain name */
199	int qclass, qtype;	/* class and type of query */
200	u_char *answer;		/* buffer to put answer */
201	int anslen;		/* size of answer buffer */
202	int n;			/* result length */
203};
204
205static int str_isnumber __P((const char *));
206static int explore_fqdn __P((const struct addrinfo *, const char *,
207	const char *, struct addrinfo **));
208static int explore_null __P((const struct addrinfo *,
209	const char *, struct addrinfo **));
210static int explore_numeric __P((const struct addrinfo *, const char *,
211	const char *, struct addrinfo **));
212static int explore_numeric_scope __P((const struct addrinfo *, const char *,
213	const char *, struct addrinfo **));
214static int get_canonname __P((const struct addrinfo *,
215	struct addrinfo *, const char *));
216static struct addrinfo *get_ai __P((const struct addrinfo *,
217	const struct afd *, const char *));
218static int get_portmatch __P((const struct addrinfo *, const char *));
219static int get_port __P((struct addrinfo *, const char *, int));
220static const struct afd *find_afd __P((int));
221static int addrconfig __P((struct addrinfo *));
222#ifdef INET6
223static int ip6_str2scopeid __P((char *, struct sockaddr_in6 *));
224#endif
225
226static struct addrinfo *getanswer __P((const querybuf *, int, const char *,
227				       int, const struct addrinfo *));
228static int _dns_getaddrinfo __P((const struct addrinfo *, const char *,
229				 struct addrinfo **));
230static struct addrinfo *_gethtent __P((FILE *fp, const char *,
231				       const struct addrinfo *));
232static int _files_getaddrinfo __P((const struct addrinfo *, const char *,
233				   struct addrinfo **));
234#ifdef YP
235static int _nis_getaddrinfo __P((const struct addrinfo *, const char *,
236				 struct addrinfo **));
237#endif
238
239static int res_queryN __P((const char *, struct res_target *));
240static int res_searchN __P((const char *, struct res_target *));
241static int res_querydomainN __P((const char *, const char *,
242				 struct res_target *));
243
244
245static char *ai_errlist[] = {
246	"Success",
247	"Address family for hostname not supported",	/* EAI_ADDRFAMILY */
248	"Temporary failure in name resolution",		/* EAI_AGAIN      */
249	"Invalid value for ai_flags",		       	/* EAI_BADFLAGS   */
250	"Non-recoverable failure in name resolution", 	/* EAI_FAIL       */
251	"ai_family not supported",			/* EAI_FAMILY     */
252	"Memory allocation failure", 			/* EAI_MEMORY     */
253	"No address associated with hostname", 		/* EAI_NODATA     */
254	"hostname nor servname provided, or not known",	/* EAI_NONAME     */
255	"servname not supported for ai_socktype",	/* EAI_SERVICE    */
256	"ai_socktype not supported", 			/* EAI_SOCKTYPE   */
257	"System error returned in errno", 		/* EAI_SYSTEM     */
258	"Invalid value for hints",			/* EAI_BADHINTS	  */
259	"Resolved protocol is unknown",			/* EAI_PROTOCOL   */
260#ifdef EAI_RESNULL
261	"Argument res is NULL",				/* EAI_RESNULL	  */
262#endif
263	"Unknown error", 				/* EAI_MAX        */
264};
265
266/*
267 * Select order host function.
268 */
269#define	MAXHOSTCONF	4
270
271#ifndef HOSTCONF
272#  define	HOSTCONF	"/etc/host.conf"
273#endif /* !HOSTCONF */
274
275struct _hostconf {
276	int (*byname)(const struct addrinfo *, const char *,
277		      struct addrinfo **);
278};
279
280/* default order */
281static struct _hostconf _hostconf[MAXHOSTCONF] = {
282	_dns_getaddrinfo,
283	_files_getaddrinfo,
284#ifdef ICMPNL
285	NULL,
286#endif /* ICMPNL */
287};
288
289static int	_hostconf_init_done;
290static void	_hostconf_init(void);
291
292/* XXX macros that make external reference is BAD. */
293
294#define	GET_AI(ai, afd, addr) \
295do { \
296	/* external reference: pai, error, and label free */ \
297	(ai) = get_ai(pai, (afd), (addr)); \
298	if ((ai) == NULL) { \
299		error = EAI_MEMORY; \
300		goto free; \
301	} \
302} while (/*CONSTCOND*/0)
303
304#define	GET_PORT(ai, serv) \
305do { \
306	/* external reference: error and label free */ \
307	error = get_port((ai), (serv), 0); \
308	if (error != 0) \
309		goto free; \
310} while (/*CONSTCOND*/0)
311
312#define	GET_CANONNAME(ai, str) \
313do { \
314	/* external reference: pai, error and label free */ \
315	error = get_canonname(pai, (ai), (str)); \
316	if (error != 0) \
317		goto free; \
318} while (/*CONSTCOND*/0)
319
320#define	ERR(err) \
321do { \
322	/* external reference: error, and label bad */ \
323	error = (err); \
324	goto bad; \
325	/*NOTREACHED*/ \
326} while (/*CONSTCOND*/0)
327
328#define	MATCH_FAMILY(x, y, w) \
329	((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || (y) == PF_UNSPEC)))
330#define	MATCH(x, y, w) \
331	((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY)))
332
333char *
334gai_strerror(ecode)
335	int ecode;
336{
337	if (ecode < 0 || ecode > EAI_MAX)
338		ecode = EAI_MAX;
339	return ai_errlist[ecode];
340}
341
342void
343freeaddrinfo(ai)
344	struct addrinfo *ai;
345{
346	struct addrinfo *next;
347
348	do {
349		next = ai->ai_next;
350		if (ai->ai_canonname)
351			free(ai->ai_canonname);
352		/* no need to free(ai->ai_addr) */
353		free(ai);
354		ai = next;
355	} while (ai);
356}
357
358static int
359str_isnumber(p)
360	const char *p;
361{
362	const char *q = (const char *)p;
363	while (*q) {
364		if (!isdigit(*q))
365			return NO;
366		q++;
367	}
368	return YES;
369}
370
371int
372getaddrinfo(hostname, servname, hints, res)
373	const char *hostname, *servname;
374	const struct addrinfo *hints;
375	struct addrinfo **res;
376{
377	struct addrinfo sentinel;
378	struct addrinfo *cur;
379	int error = 0;
380	struct addrinfo ai;
381	struct addrinfo ai0;
382	struct addrinfo *pai;
383	const struct explore *ex;
384
385	memset(&sentinel, 0, sizeof(sentinel));
386	cur = &sentinel;
387	pai = &ai;
388	pai->ai_flags = 0;
389	pai->ai_family = PF_UNSPEC;
390	pai->ai_socktype = ANY;
391	pai->ai_protocol = ANY;
392	pai->ai_addrlen = 0;
393	pai->ai_canonname = NULL;
394	pai->ai_addr = NULL;
395	pai->ai_next = NULL;
396
397	if (hostname == NULL && servname == NULL)
398		return EAI_NONAME;
399#ifdef EAI_RESNULL
400	if (res == NULL)
401		return EAI_RESNULL; /* xxx */
402#endif
403	if (hints) {
404		/* error check for hints */
405		if (hints->ai_addrlen || hints->ai_canonname ||
406		    hints->ai_addr || hints->ai_next)
407			ERR(EAI_BADHINTS); /* xxx */
408		if (hints->ai_flags & ~AI_MASK)
409			ERR(EAI_BADFLAGS);
410		switch (hints->ai_family) {
411		case PF_UNSPEC:
412		case PF_INET:
413#ifdef INET6
414		case PF_INET6:
415#endif
416			break;
417		default:
418			ERR(EAI_FAMILY);
419		}
420		memcpy(pai, hints, sizeof(*pai));
421
422		/*
423		 * if both socktype/protocol are specified, check if they
424		 * are meaningful combination.
425		 */
426		if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
427			for (ex = explore; ex->e_af >= 0; ex++) {
428				if (pai->ai_family != ex->e_af)
429					continue;
430				if (ex->e_socktype == ANY)
431					continue;
432				if (ex->e_protocol == ANY)
433					continue;
434				if (pai->ai_socktype == ex->e_socktype
435				 && pai->ai_protocol != ex->e_protocol) {
436					ERR(EAI_BADHINTS);
437				}
438			}
439		}
440	}
441
442	/*
443	 * post-2553: AI_ALL and AI_V4MAPPED are effective only against
444	 * AF_INET6 query.  They needs to be ignored if specified in other
445	 * occassions.
446	 */
447	switch (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) {
448	case AI_V4MAPPED:
449	case AI_ALL | AI_V4MAPPED:
450		if (pai->ai_family != AF_INET6)
451			pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
452		break;
453	case AI_ALL:
454#if 1
455		/* illegal */
456		ERR(EAI_BADFLAGS);
457#else
458		pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
459#endif
460		break;
461	}
462
463	/*
464	 * check for special cases.  (1) numeric servname is disallowed if
465	 * socktype/protocol are left unspecified. (2) servname is disallowed
466	 * for raw and other inet{,6} sockets.
467	 */
468	if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
469#ifdef PF_INET6
470	    || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
471#endif
472	    ) {
473		ai0 = *pai;	/* backup *pai */
474
475		if (pai->ai_family == PF_UNSPEC) {
476#ifdef PF_INET6
477			pai->ai_family = PF_INET6;
478#else
479			pai->ai_family = PF_INET;
480#endif
481		}
482		error = get_portmatch(pai, servname);
483		if (error)
484			ERR(error);
485
486		*pai = ai0;
487	}
488
489	ai0 = *pai;
490
491	/* NULL hostname, or numeric hostname */
492	for (ex = explore; ex->e_af >= 0; ex++) {
493		*pai = ai0;
494
495		/* PF_UNSPEC entries are prepared for DNS queries only */
496		if (ex->e_af == PF_UNSPEC)
497			continue;
498
499		if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
500			continue;
501		if (!MATCH(pai->ai_socktype, ex->e_socktype,
502			   WILD_SOCKTYPE(ex)))
503			continue;
504		if (!MATCH(pai->ai_protocol, ex->e_protocol,
505			   WILD_PROTOCOL(ex)))
506			continue;
507
508		if (pai->ai_family == PF_UNSPEC)
509			pai->ai_family = ex->e_af;
510		if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
511			pai->ai_socktype = ex->e_socktype;
512		if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
513			pai->ai_protocol = ex->e_protocol;
514
515		if (hostname == NULL)
516			error = explore_null(pai, servname, &cur->ai_next);
517		else
518			error = explore_numeric_scope(pai, hostname, servname,
519						      &cur->ai_next);
520
521		if (error)
522			goto free;
523
524		while (cur && cur->ai_next)
525			cur = cur->ai_next;
526	}
527
528	/*
529	 * XXX
530	 * If numreic representation of AF1 can be interpreted as FQDN
531	 * representation of AF2, we need to think again about the code below.
532	 */
533	if (sentinel.ai_next)
534		goto good;
535
536	if (pai->ai_flags & AI_NUMERICHOST)
537		ERR(EAI_NODATA);
538	if (hostname == NULL)
539		ERR(EAI_NODATA);
540
541#if 1
542	/* XXX: temporarily, behave as if AI_ADDRCONFIG is specified */
543	pai->ai_flags |= AI_ADDRCONFIG;
544#endif
545	if ((pai->ai_flags & AI_ADDRCONFIG) != 0 && !addrconfig(&ai0))
546		ERR(EAI_FAIL);
547
548	/*
549	 * hostname as alphabetical name.
550	 * we would like to prefer AF_INET6 than AF_INET, so we'll make a
551	 * outer loop by AFs.
552	 */
553	for (ex = explore; ex->e_af >= 0; ex++) {
554		*pai = ai0;
555
556		/* require exact match for family field */
557		if (pai->ai_family != ex->e_af)
558			continue;
559
560		if (!MATCH(pai->ai_socktype, ex->e_socktype,
561			   WILD_SOCKTYPE(ex))) {
562			continue;
563		}
564		if (!MATCH(pai->ai_protocol, ex->e_protocol,
565			   WILD_PROTOCOL(ex))) {
566			continue;
567		}
568
569		if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
570			pai->ai_socktype = ex->e_socktype;
571		if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
572			pai->ai_protocol = ex->e_protocol;
573
574		error = explore_fqdn(pai, hostname, servname, &cur->ai_next);
575
576		while (cur && cur->ai_next)
577			cur = cur->ai_next;
578	}
579
580	/* XXX */
581	if (sentinel.ai_next)
582		error = 0;
583
584	if (error)
585		goto free;
586	if (error == 0) {
587		if (sentinel.ai_next) {
588 good:
589			*res = sentinel.ai_next;
590			return SUCCESS;
591		} else
592			error = EAI_FAIL;
593	}
594 free:
595 bad:
596	if (sentinel.ai_next)
597		freeaddrinfo(sentinel.ai_next);
598	*res = NULL;
599	return error;
600}
601
602static char *
603_hgetword(char **pp)
604{
605	char c, *p, *ret;
606	const char *sp;
607	static const char sep[] = "# \t\n";
608
609	ret = NULL;
610	for (p = *pp; (c = *p) != '\0'; p++) {
611		for (sp = sep; *sp != '\0'; sp++) {
612			if (c == *sp)
613				break;
614		}
615		if (c == '#')
616			p[1] = '\0';	/* ignore rest of line */
617		if (ret == NULL) {
618			if (*sp == '\0')
619				ret = p;
620		} else {
621			if (*sp != '\0') {
622				*p++ = '\0';
623				break;
624			}
625		}
626	}
627	*pp = p;
628	if (ret == NULL || *ret == '\0')
629		return NULL;
630	return ret;
631}
632
633/*
634 * Initialize hostconf structure.
635 */
636
637static void
638_hostconf_init(void)
639{
640	FILE *fp;
641	int n;
642	char *p, *line;
643	char buf[BUFSIZ];
644
645	_hostconf_init_done = 1;
646	n = 0;
647	p = HOSTCONF;
648	if ((fp = fopen(p, "r")) == NULL)
649		return;
650	while (n < MAXHOSTCONF && fgets(buf, sizeof(buf), fp)) {
651		line = buf;
652		if ((p = _hgetword(&line)) == NULL)
653			continue;
654		do {
655			if (strcmp(p, "hosts") == 0
656			||  strcmp(p, "local") == 0
657			||  strcmp(p, "file") == 0
658			||  strcmp(p, "files") == 0)
659				_hostconf[n++].byname = _files_getaddrinfo;
660			else if (strcmp(p, "dns") == 0
661			     ||  strcmp(p, "bind") == 0)
662				_hostconf[n++].byname = _dns_getaddrinfo;
663#ifdef YP
664			else if (strcmp(p, "nis") == 0)
665				_hostconf[n++].byname = _nis_getaddrinfo;
666#endif
667		} while ((p = _hgetword(&line)) != NULL);
668	}
669	fclose(fp);
670	if (n < 0) {
671		/* no keyword found. do not change default configuration */
672		return;
673	}
674	for (; n < MAXHOSTCONF; n++)
675		_hostconf[n].byname = NULL;
676}
677
678/*
679 * FQDN hostname, DNS lookup
680 */
681static int
682explore_fqdn(pai, hostname, servname, res)
683	const struct addrinfo *pai;
684	const char *hostname;
685	const char *servname;
686	struct addrinfo **res;
687{
688	struct addrinfo *result;
689	struct addrinfo *cur;
690	int error = 0, i;
691
692	result = NULL;
693	*res = NULL;
694
695	/*
696	 * if the servname does not match socktype/protocol, ignore it.
697	 */
698	if (get_portmatch(pai, servname) != 0)
699		return 0;
700
701	if (!_hostconf_init_done)
702		_hostconf_init();
703
704	for (i = 0; i < MAXHOSTCONF; i++) {
705		if (!_hostconf[i].byname)
706			continue;
707		error = (*_hostconf[i].byname)(pai, hostname, &result);
708		if (error != 0)
709			continue;
710		for (cur = result; cur; cur = cur->ai_next) {
711			GET_PORT(cur, servname);
712			/* canonname should be filled already */
713		}
714		*res = result;
715		return 0;
716	}
717
718free:
719	if (result)
720		freeaddrinfo(result);
721	return error;
722}
723
724/*
725 * hostname == NULL.
726 * passive socket -> anyaddr (0.0.0.0 or ::)
727 * non-passive socket -> localhost (127.0.0.1 or ::1)
728 */
729static int
730explore_null(pai, servname, res)
731	const struct addrinfo *pai;
732	const char *servname;
733	struct addrinfo **res;
734{
735	int s;
736	const struct afd *afd;
737	struct addrinfo *cur;
738	struct addrinfo sentinel;
739	int error;
740
741	*res = NULL;
742	sentinel.ai_next = NULL;
743	cur = &sentinel;
744
745	/*
746	 * filter out AFs that are not supported by the kernel
747	 * XXX errno?
748	 */
749	s = socket(pai->ai_family, SOCK_DGRAM, 0);
750	if (s < 0) {
751		if (errno != EMFILE)
752			return 0;
753	} else
754		_close(s);
755
756	/*
757	 * if the servname does not match socktype/protocol, ignore it.
758	 */
759	if (get_portmatch(pai, servname) != 0)
760		return 0;
761
762	afd = find_afd(pai->ai_family);
763	if (afd == NULL)
764		return 0;
765
766	if (pai->ai_flags & AI_PASSIVE) {
767		GET_AI(cur->ai_next, afd, afd->a_addrany);
768		/* xxx meaningless?
769		 * GET_CANONNAME(cur->ai_next, "anyaddr");
770		 */
771		GET_PORT(cur->ai_next, servname);
772	} else {
773		GET_AI(cur->ai_next, afd, afd->a_loopback);
774		/* xxx meaningless?
775		 * GET_CANONNAME(cur->ai_next, "localhost");
776		 */
777		GET_PORT(cur->ai_next, servname);
778	}
779	cur = cur->ai_next;
780
781	*res = sentinel.ai_next;
782	return 0;
783
784free:
785	if (sentinel.ai_next)
786		freeaddrinfo(sentinel.ai_next);
787	return error;
788}
789
790/*
791 * numeric hostname
792 */
793static int
794explore_numeric(pai, hostname, servname, res)
795	const struct addrinfo *pai;
796	const char *hostname;
797	const char *servname;
798	struct addrinfo **res;
799{
800	const struct afd *afd;
801	struct addrinfo *cur;
802	struct addrinfo sentinel;
803	int error;
804	char pton[PTON_MAX];
805
806	*res = NULL;
807	sentinel.ai_next = NULL;
808	cur = &sentinel;
809
810	/*
811	 * if the servname does not match socktype/protocol, ignore it.
812	 */
813	if (get_portmatch(pai, servname) != 0)
814		return 0;
815
816	afd = find_afd(pai->ai_family);
817	if (afd == NULL)
818		return 0;
819
820	switch (afd->a_af) {
821#if 1 /*X/Open spec*/
822	case AF_INET:
823		if (inet_aton(hostname, (struct in_addr *)pton) == 1) {
824			if (pai->ai_family == afd->a_af ||
825			    pai->ai_family == PF_UNSPEC /*?*/) {
826				GET_AI(cur->ai_next, afd, pton);
827				GET_PORT(cur->ai_next, servname);
828				while (cur && cur->ai_next)
829					cur = cur->ai_next;
830			} else
831				ERR(EAI_FAMILY);	/*xxx*/
832		}
833		break;
834#endif
835	default:
836		if (inet_pton(afd->a_af, hostname, pton) == 1) {
837			if (pai->ai_family == afd->a_af ||
838			    pai->ai_family == PF_UNSPEC /*?*/) {
839				GET_AI(cur->ai_next, afd, pton);
840				GET_PORT(cur->ai_next, servname);
841				while (cur && cur->ai_next)
842					cur = cur->ai_next;
843			} else
844				ERR(EAI_FAMILY);	/*xxx*/
845		}
846		break;
847	}
848
849	*res = sentinel.ai_next;
850	return 0;
851
852free:
853bad:
854	if (sentinel.ai_next)
855		freeaddrinfo(sentinel.ai_next);
856	return error;
857}
858
859/*
860 * numeric hostname with scope
861 */
862static int
863explore_numeric_scope(pai, hostname, servname, res)
864	const struct addrinfo *pai;
865	const char *hostname;
866	const char *servname;
867	struct addrinfo **res;
868{
869#if !defined(SCOPE_DELIMITER) || !defined(INET6)
870	return explore_numeric(pai, hostname, servname, res);
871#else
872	const struct afd *afd;
873	struct addrinfo *cur;
874	int error;
875	char *cp, *hostname2 = NULL, *scope, *addr;
876	struct sockaddr_in6 *sin6;
877
878	/*
879	 * if the servname does not match socktype/protocol, ignore it.
880	 */
881	if (get_portmatch(pai, servname) != 0)
882		return 0;
883
884	afd = find_afd(pai->ai_family);
885	if (afd == NULL)
886		return 0;
887	if (!afd->a_scoped)
888		return explore_numeric(pai, hostname, servname, res);
889
890	cp = strchr(hostname, SCOPE_DELIMITER);
891	if (cp == NULL)
892		return explore_numeric(pai, hostname, servname, res);
893
894	/*
895	 * Handle special case of <scoped_address><delimiter><scope id>
896	 */
897	hostname2 = strdup(hostname);
898	if (hostname2 == NULL)
899		return EAI_MEMORY;
900	/* terminate at the delimiter */
901	hostname2[cp - hostname] = '\0';
902	addr = hostname2;
903	scope = cp + 1;
904
905	error = explore_numeric(pai, addr, servname, res);
906	if (error == 0) {
907		int scopeid;
908
909		for (cur = *res; cur; cur = cur->ai_next) {
910			if (cur->ai_family != AF_INET6)
911				continue;
912			sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
913			if ((scopeid = ip6_str2scopeid(scope, sin6)) == -1) {
914				free(hostname2);
915				return(EAI_NODATA); /* XXX: is return OK? */
916			}
917			sin6->sin6_scope_id = scopeid;
918		}
919	}
920
921	free(hostname2);
922
923	return error;
924#endif
925}
926
927static int
928get_canonname(pai, ai, str)
929	const struct addrinfo *pai;
930	struct addrinfo *ai;
931	const char *str;
932{
933	if ((pai->ai_flags & AI_CANONNAME) != 0) {
934		ai->ai_canonname = (char *)malloc(strlen(str) + 1);
935		if (ai->ai_canonname == NULL)
936			return EAI_MEMORY;
937		strcpy(ai->ai_canonname, str);
938	}
939	return 0;
940}
941
942static struct addrinfo *
943get_ai(pai, afd, addr)
944	const struct addrinfo *pai;
945	const struct afd *afd;
946	const char *addr;
947{
948	char *p;
949	struct addrinfo *ai;
950#ifdef FAITH
951	struct in6_addr faith_prefix;
952	char *fp_str;
953	int translate = 0;
954#endif
955
956#ifdef FAITH
957	/*
958	 * Transfrom an IPv4 addr into a special IPv6 addr format for
959	 * IPv6->IPv4 translation gateway. (only TCP is supported now)
960	 *
961	 * +-----------------------------------+------------+
962	 * | faith prefix part (12 bytes)      | embedded   |
963	 * |                                   | IPv4 addr part (4 bytes)
964	 * +-----------------------------------+------------+
965	 *
966	 * faith prefix part is specified as ascii IPv6 addr format
967	 * in environmental variable GAI.
968	 * For FAITH to work correctly, routing to faith prefix must be
969	 * setup toward a machine where a FAITH daemon operates.
970	 * Also, the machine must enable some mechanizm
971	 * (e.g. faith interface hack) to divert those packet with
972	 * faith prefixed destination addr to user-land FAITH daemon.
973	 */
974	fp_str = getenv("GAI");
975	if (fp_str && inet_pton(AF_INET6, fp_str, &faith_prefix) == 1 &&
976	    afd->a_af == AF_INET && pai->ai_socktype == SOCK_STREAM) {
977		u_int32_t v4a;
978		u_int8_t v4a_top;
979
980		memcpy(&v4a, addr, sizeof v4a);
981		v4a_top = v4a >> IN_CLASSA_NSHIFT;
982		if (!IN_MULTICAST(v4a) && !IN_EXPERIMENTAL(v4a) &&
983		    v4a_top != 0 && v4a != IN_LOOPBACKNET) {
984			afd = &afdl[N_INET6];
985			memcpy(&faith_prefix.s6_addr[12], addr,
986			       sizeof(struct in_addr));
987			translate = 1;
988		}
989	}
990#endif
991
992	ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
993		+ (afd->a_socklen));
994	if (ai == NULL)
995		return NULL;
996
997	memcpy(ai, pai, sizeof(struct addrinfo));
998	ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
999	memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
1000	ai->ai_addr->sa_len = afd->a_socklen;
1001	ai->ai_addrlen = afd->a_socklen;
1002	ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
1003	p = (char *)(ai->ai_addr);
1004#ifdef FAITH
1005	if (translate == 1)
1006		memcpy(p + afd->a_off, &faith_prefix, afd->a_addrlen);
1007	else
1008#endif
1009	memcpy(p + afd->a_off, addr, afd->a_addrlen);
1010
1011	return ai;
1012}
1013
1014static int
1015get_portmatch(ai, servname)
1016	const struct addrinfo *ai;
1017	const char *servname;
1018{
1019
1020	/* get_port does not touch first argument. when matchonly == 1. */
1021	/* LINTED const cast */
1022	return get_port((struct addrinfo *)ai, servname, 1);
1023}
1024
1025static int
1026get_port(ai, servname, matchonly)
1027	struct addrinfo *ai;
1028	const char *servname;
1029	int matchonly;
1030{
1031	const char *proto;
1032	struct servent *sp;
1033	int port;
1034	int allownumeric;
1035
1036	if (servname == NULL)
1037		return 0;
1038	switch (ai->ai_family) {
1039	case AF_INET:
1040#ifdef AF_INET6
1041	case AF_INET6:
1042#endif
1043		break;
1044	default:
1045		return 0;
1046	}
1047
1048	switch (ai->ai_socktype) {
1049	case SOCK_RAW:
1050		return EAI_SERVICE;
1051	case SOCK_DGRAM:
1052	case SOCK_STREAM:
1053		allownumeric = 1;
1054		break;
1055	case ANY:
1056		allownumeric = 0;
1057		break;
1058	default:
1059		return EAI_SOCKTYPE;
1060	}
1061
1062	if (str_isnumber(servname)) {
1063		if (!allownumeric)
1064			return EAI_SERVICE;
1065		port = htons(atoi(servname));
1066		if (port < 0 || port > 65535)
1067			return EAI_SERVICE;
1068	} else {
1069		switch (ai->ai_socktype) {
1070		case SOCK_DGRAM:
1071			proto = "udp";
1072			break;
1073		case SOCK_STREAM:
1074			proto = "tcp";
1075			break;
1076		default:
1077			proto = NULL;
1078			break;
1079		}
1080
1081		if ((sp = getservbyname(servname, proto)) == NULL)
1082			return EAI_SERVICE;
1083		port = sp->s_port;
1084	}
1085
1086	if (!matchonly) {
1087		switch (ai->ai_family) {
1088		case AF_INET:
1089			((struct sockaddr_in *)(void *)
1090			    ai->ai_addr)->sin_port = port;
1091			break;
1092#ifdef INET6
1093		case AF_INET6:
1094			((struct sockaddr_in6 *)(void *)
1095			    ai->ai_addr)->sin6_port = port;
1096			break;
1097#endif
1098		}
1099	}
1100
1101	return 0;
1102}
1103
1104static const struct afd *
1105find_afd(af)
1106	int af;
1107{
1108	const struct afd *afd;
1109
1110	if (af == PF_UNSPEC)
1111		return NULL;
1112	for (afd = afdl; afd->a_af; afd++) {
1113		if (afd->a_af == af)
1114			return afd;
1115	}
1116	return NULL;
1117}
1118
1119/*
1120 * post-2553: AI_ADDRCONFIG check.  if we use getipnodeby* as backend, backend
1121 * will take care of it.
1122 * the semantics of AI_ADDRCONFIG is not defined well.  we are not sure
1123 * if the code is right or not.
1124 *
1125 * XXX PF_UNSPEC -> PF_INET6 + PF_INET mapping needs to be in sync with
1126 * _dns_getaddrinfo.
1127 */
1128static int
1129addrconfig(pai)
1130	struct addrinfo *pai;
1131{
1132	int s, af;
1133
1134	/*
1135	 * TODO:
1136	 * Note that implementation dependent test for address
1137	 * configuration should be done everytime called
1138	 * (or apropriate interval),
1139	 * because addresses will be dynamically assigned or deleted.
1140	 */
1141	af = pai->ai_family;
1142	if (af == AF_UNSPEC) {
1143		if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
1144			af = AF_INET;
1145		else {
1146			close(s);
1147			if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
1148				af = AF_INET6;
1149			else
1150				close(s);
1151		}
1152
1153	}
1154	if (af != AF_UNSPEC) {
1155		if ((s = socket(af, SOCK_DGRAM, 0)) < 0)
1156			return 0;
1157		close(s);
1158	}
1159	pai->ai_family = af;
1160	return 1;
1161}
1162
1163#ifdef INET6
1164/* convert a string to a scope identifier. XXX: IPv6 specific */
1165static int
1166ip6_str2scopeid(scope, sin6)
1167	char *scope;
1168	struct sockaddr_in6 *sin6;
1169{
1170	int scopeid;
1171	struct in6_addr *a6 = &sin6->sin6_addr;
1172	char *ep;
1173
1174	if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) {
1175		/*
1176		 * We currently assume a one-to-one mapping between links
1177		 * and interfaces, so we simply use interface indices for
1178		 * like-local scopes.
1179		 */
1180		scopeid = if_nametoindex(scope);
1181		if (scopeid == 0)
1182			goto trynumeric;
1183		return(scopeid);
1184	}
1185
1186	/* still unclear about literal, allow numeric only - placeholder */
1187	if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
1188		goto trynumeric;
1189	if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
1190		goto trynumeric;
1191	else
1192		goto trynumeric;	/* global */
1193
1194	/* try to convert to a numeric id as a last resort */
1195  trynumeric:
1196	scopeid = (int)strtoul(scope, &ep, 10);
1197	if (*ep == '\0')
1198		return scopeid;
1199	else
1200		return -1;
1201}
1202#endif
1203
1204#ifdef DEBUG
1205static const char AskedForGot[] =
1206	"gethostby*.getanswer: asked for \"%s\", got \"%s\"";
1207#endif
1208
1209static struct addrinfo *
1210getanswer(answer, anslen, qname, qtype, pai)
1211	const querybuf *answer;
1212	int anslen;
1213	const char *qname;
1214	int qtype;
1215	const struct addrinfo *pai;
1216{
1217	struct addrinfo sentinel, *cur;
1218	struct addrinfo ai;
1219	const struct afd *afd;
1220	char *canonname;
1221	const HEADER *hp;
1222	const u_char *cp;
1223	int n;
1224	const u_char *eom;
1225	char *bp;
1226	int type, class, buflen, ancount, qdcount;
1227	int haveanswer, had_error;
1228	char tbuf[MAXDNAME];
1229	int (*name_ok) __P((const char *));
1230	char hostbuf[8*1024];
1231
1232	memset(&sentinel, 0, sizeof(sentinel));
1233	cur = &sentinel;
1234
1235	canonname = NULL;
1236	eom = answer->buf + anslen;
1237	switch (qtype) {
1238	case T_A:
1239	case T_AAAA:
1240	case T_ANY:	/*use T_ANY only for T_A/T_AAAA lookup*/
1241		name_ok = res_hnok;
1242		break;
1243	default:
1244		return (NULL);	/* XXX should be abort(); */
1245	}
1246	/*
1247	 * find first satisfactory answer
1248	 */
1249	hp = &answer->hdr;
1250	ancount = ntohs(hp->ancount);
1251	qdcount = ntohs(hp->qdcount);
1252	bp = hostbuf;
1253	buflen = sizeof hostbuf;
1254	cp = answer->buf + HFIXEDSZ;
1255	if (qdcount != 1) {
1256		h_errno = NO_RECOVERY;
1257		return (NULL);
1258	}
1259	n = dn_expand(answer->buf, eom, cp, bp, buflen);
1260	if ((n < 0) || !(*name_ok)(bp)) {
1261		h_errno = NO_RECOVERY;
1262		return (NULL);
1263	}
1264	cp += n + QFIXEDSZ;
1265	if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
1266		/* res_send() has already verified that the query name is the
1267		 * same as the one we sent; this just gets the expanded name
1268		 * (i.e., with the succeeding search-domain tacked on).
1269		 */
1270		n = strlen(bp) + 1;		/* for the \0 */
1271		if (n >= MAXHOSTNAMELEN) {
1272			h_errno = NO_RECOVERY;
1273			return (NULL);
1274		}
1275		canonname = bp;
1276		bp += n;
1277		buflen -= n;
1278		/* The qname can be abbreviated, but h_name is now absolute. */
1279		qname = canonname;
1280	}
1281	haveanswer = 0;
1282	had_error = 0;
1283	while (ancount-- > 0 && cp < eom && !had_error) {
1284		n = dn_expand(answer->buf, eom, cp, bp, buflen);
1285		if ((n < 0) || !(*name_ok)(bp)) {
1286			had_error++;
1287			continue;
1288		}
1289		cp += n;			/* name */
1290		type = _getshort(cp);
1291 		cp += INT16SZ;			/* type */
1292		class = _getshort(cp);
1293 		cp += INT16SZ + INT32SZ;	/* class, TTL */
1294		n = _getshort(cp);
1295		cp += INT16SZ;			/* len */
1296		if (class != C_IN) {
1297			/* XXX - debug? syslog? */
1298			cp += n;
1299			continue;		/* XXX - had_error++ ? */
1300		}
1301		if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
1302		    type == T_CNAME) {
1303			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
1304			if ((n < 0) || !(*name_ok)(tbuf)) {
1305				had_error++;
1306				continue;
1307			}
1308			cp += n;
1309			/* Get canonical name. */
1310			n = strlen(tbuf) + 1;	/* for the \0 */
1311			if (n > buflen || n >= MAXHOSTNAMELEN) {
1312				had_error++;
1313				continue;
1314			}
1315			strcpy(bp, tbuf);
1316			canonname = bp;
1317			bp += n;
1318			buflen -= n;
1319			continue;
1320		}
1321		if (qtype == T_ANY) {
1322			if (!(type == T_A || type == T_AAAA)) {
1323				cp += n;
1324				continue;
1325			}
1326		} else if (type != qtype) {
1327#ifdef DEBUG
1328			if (type != T_KEY && type != T_SIG)
1329				syslog(LOG_NOTICE|LOG_AUTH,
1330	       "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
1331				       qname, p_class(C_IN), p_type(qtype),
1332				       p_type(type));
1333#endif
1334			cp += n;
1335			continue;		/* XXX - had_error++ ? */
1336		}
1337		switch (type) {
1338		case T_A:
1339		case T_AAAA:
1340			if (strcasecmp(canonname, bp) != 0) {
1341#ifdef DEBUG
1342				syslog(LOG_NOTICE|LOG_AUTH,
1343				       AskedForGot, canonname, bp);
1344#endif
1345				cp += n;
1346				continue;	/* XXX - had_error++ ? */
1347			}
1348			if (type == T_A && n != INADDRSZ) {
1349				cp += n;
1350				continue;
1351			}
1352			if (type == T_AAAA && n != IN6ADDRSZ) {
1353				cp += n;
1354				continue;
1355			}
1356#ifdef FILTER_V4MAPPED
1357			if (type == T_AAAA) {
1358				struct in6_addr in6;
1359				memcpy(&in6, cp, sizeof(in6));
1360				if (IN6_IS_ADDR_V4MAPPED(&in6)) {
1361					cp += n;
1362					continue;
1363				}
1364			}
1365#endif
1366			if (!haveanswer) {
1367				int nn;
1368
1369				canonname = bp;
1370				nn = strlen(bp) + 1;	/* for the \0 */
1371				bp += nn;
1372				buflen -= nn;
1373			}
1374
1375			/* don't overwrite pai */
1376			ai = *pai;
1377			ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
1378			afd = find_afd(ai.ai_family);
1379			if (afd == NULL) {
1380				cp += n;
1381				continue;
1382			}
1383			cur->ai_next = get_ai(&ai, afd, (const char *)cp);
1384			if (cur->ai_next == NULL)
1385				had_error++;
1386			while (cur && cur->ai_next)
1387				cur = cur->ai_next;
1388			cp += n;
1389			break;
1390		default:
1391			abort();
1392		}
1393		if (!had_error)
1394			haveanswer++;
1395	}
1396	if (haveanswer) {
1397		if (!canonname)
1398			(void)get_canonname(pai, sentinel.ai_next, qname);
1399		else
1400			(void)get_canonname(pai, sentinel.ai_next, canonname);
1401		h_errno = NETDB_SUCCESS;
1402		return sentinel.ai_next;
1403	}
1404
1405	h_errno = NO_RECOVERY;
1406	return NULL;
1407}
1408
1409/*ARGSUSED*/
1410static int
1411_dns_getaddrinfo(pai, hostname, res)
1412	const struct addrinfo *pai;
1413	const char *hostname;
1414	struct addrinfo **res;
1415{
1416	struct addrinfo *ai;
1417	querybuf buf, buf2;
1418	const char *name;
1419	struct addrinfo sentinel, *cur;
1420	struct res_target q, q2;
1421
1422	memset(&q, 0, sizeof(q2));
1423	memset(&q2, 0, sizeof(q2));
1424	memset(&sentinel, 0, sizeof(sentinel));
1425	cur = &sentinel;
1426
1427	switch (pai->ai_family) {
1428	case AF_UNSPEC:
1429		/* prefer IPv6 */
1430		q.qclass = C_IN;
1431		q.qtype = T_AAAA;
1432		q.answer = buf.buf;
1433		q.anslen = sizeof(buf);
1434		q.next = &q2;
1435		q2.qclass = C_IN;
1436		q2.qtype = T_A;
1437		q2.answer = buf2.buf;
1438		q2.anslen = sizeof(buf2);
1439		break;
1440	case AF_INET:
1441		q.qclass = C_IN;
1442		q.qtype = T_A;
1443		q.answer = buf.buf;
1444		q.anslen = sizeof(buf);
1445		break;
1446	case AF_INET6:
1447		q.qclass = C_IN;
1448		q.qtype = T_AAAA;
1449		q.answer = buf.buf;
1450		q.anslen = sizeof(buf);
1451		break;
1452	default:
1453		return EAI_FAIL;
1454	}
1455	if (res_searchN(hostname, &q) < 0)
1456		return EAI_NODATA;
1457	ai = getanswer(&buf, q.n, q.name, q.qtype, pai);
1458	if (ai) {
1459		cur->ai_next = ai;
1460		while (cur && cur->ai_next)
1461			cur = cur->ai_next;
1462	}
1463	if (q.next) {
1464		ai = getanswer(&buf2, q2.n, q2.name, q2.qtype, pai);
1465		if (ai)
1466			cur->ai_next = ai;
1467	}
1468	if (sentinel.ai_next == NULL)
1469		switch (h_errno) {
1470		case HOST_NOT_FOUND:
1471			return EAI_NODATA;
1472		case TRY_AGAIN:
1473			return EAI_AGAIN;
1474		default:
1475			return EAI_FAIL;
1476		}
1477	*res = sentinel.ai_next;
1478	return 0;
1479}
1480
1481static struct addrinfo *
1482_gethtent(hostf, name, pai)
1483	FILE *hostf;
1484	const char *name;
1485	const struct addrinfo *pai;
1486{
1487	char *p;
1488	char *cp, *tname, *cname;
1489	struct addrinfo hints, *res0, *res;
1490	int error;
1491	const char *addr;
1492	char hostbuf[8*1024];
1493
1494 again:
1495	if (!(p = fgets(hostbuf, sizeof hostbuf, hostf)))
1496		return (NULL);
1497	if (*p == '#')
1498		goto again;
1499	if (!(cp = strpbrk(p, "#\n")))
1500		goto again;
1501	*cp = '\0';
1502	if (!(cp = strpbrk(p, " \t")))
1503		goto again;
1504	*cp++ = '\0';
1505	addr = p;
1506	cname = NULL;
1507	/* if this is not something we're looking for, skip it. */
1508	while (cp && *cp) {
1509		if (*cp == ' ' || *cp == '\t') {
1510			cp++;
1511			continue;
1512		}
1513		tname = cp;
1514		if (cname == NULL)
1515			cname = cp;
1516		if ((cp = strpbrk(cp, " \t")) != NULL)
1517			*cp++ = '\0';
1518		if (strcasecmp(name, tname) == 0)
1519			goto found;
1520	}
1521	goto again;
1522
1523found:
1524	hints = *pai;
1525	hints.ai_flags = AI_NUMERICHOST;
1526	error = getaddrinfo(addr, NULL, &hints, &res0);
1527	if (error)
1528		goto again;
1529#ifdef FILTER_V4MAPPED
1530	/* XXX should check all items in the chain */
1531	if (res0->ai_family == AF_INET6 &&
1532	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)res0->ai_addr)->sin6_addr)) {
1533		freeaddrinfo(res0);
1534		goto again;
1535	}
1536#endif
1537	for (res = res0; res; res = res->ai_next) {
1538		/* cover it up */
1539		res->ai_flags = pai->ai_flags;
1540
1541		if (pai->ai_flags & AI_CANONNAME) {
1542			if (get_canonname(pai, res, cname) != 0) {
1543				freeaddrinfo(res0);
1544				goto again;
1545			}
1546		}
1547	}
1548	return res0;
1549}
1550
1551/*ARGSUSED*/
1552static int
1553_files_getaddrinfo(pai, hostname, res)
1554	const struct addrinfo *pai;
1555	const char *hostname;
1556	struct addrinfo **res;
1557{
1558	FILE *hostf;
1559	struct addrinfo sentinel, *cur;
1560	struct addrinfo *p;
1561
1562	sentinel.ai_next = NULL;
1563	cur = &sentinel;
1564
1565	if ((hostf = fopen(_PATH_HOSTS, "r")) == NULL)
1566		return EAI_FAIL;
1567	while ((p = _gethtent(hostf, hostname, pai)) != NULL) {
1568		cur->ai_next = p;
1569		while (cur && cur->ai_next)
1570			cur = cur->ai_next;
1571	}
1572	fclose(hostf);
1573
1574	if (!sentinel.ai_next)
1575		return EAI_NODATA;
1576
1577	*res = sentinel.ai_next;
1578	return 0;
1579}
1580
1581#ifdef YP
1582/*ARGSUSED*/
1583static int
1584_nis_getaddrinfo(pai, hostname, res)
1585	const struct addrinfo *pai;
1586	const char *hostname;
1587	struct addrinfo **res;
1588{
1589	struct hostent *hp;
1590	int h_error;
1591	int af;
1592	struct addrinfo sentinel, *cur;
1593	int i;
1594	const struct afd *afd;
1595	int error;
1596
1597	sentinel.ai_next = NULL;
1598	cur = &sentinel;
1599
1600	af = (pai->ai_family == AF_UNSPEC) ? AF_INET : pai->ai_family;
1601	if (af != AF_INET)
1602		return (EAI_ADDRFAMILY);
1603
1604	if ((hp = _gethostbynisname(hostname, af)) == NULL) {
1605		switch (errno) {
1606		/* XXX: should be filled in */
1607		default:
1608			error = EAI_FAIL;
1609			break;
1610		}
1611	} else if (hp->h_name == NULL ||
1612		   hp->h_name[0] == 0 || hp->h_addr_list[0] == NULL) {
1613		hp = NULL;
1614		error = EAI_FAIL;
1615	}
1616
1617	if (hp == NULL)
1618		return error;
1619
1620	for (i = 0; hp->h_addr_list[i] != NULL; i++) {
1621		if (hp->h_addrtype != af)
1622			continue;
1623
1624		afd = find_afd(hp->h_addrtype);
1625		if (afd == NULL)
1626			continue;
1627
1628		GET_AI(cur->ai_next, afd, hp->h_addr_list[i]);
1629		if ((pai->ai_flags & AI_CANONNAME) != 0) {
1630			/*
1631			 * RFC2553 says that ai_canonname will be set only for
1632			 * the first element.  we do it for all the elements,
1633			 * just for convenience.
1634			 */
1635			GET_CANONNAME(cur->ai_next, hp->h_name);
1636		}
1637
1638		while (cur && cur->ai_next)
1639			cur = cur->ai_next;
1640	}
1641
1642	*res = sentinel.ai_next;
1643	return 0;
1644
1645free:
1646	if (sentinel.ai_next)
1647		freeaddrinfo(sentinel.ai_next);
1648	return error;
1649}
1650#endif
1651
1652/* resolver logic */
1653
1654extern const char *__hostalias __P((const char *));
1655extern int h_errno;
1656
1657/*
1658 * Formulate a normal query, send, and await answer.
1659 * Returned answer is placed in supplied buffer "answer".
1660 * Perform preliminary check of answer, returning success only
1661 * if no error is indicated and the answer count is nonzero.
1662 * Return the size of the response on success, -1 on error.
1663 * Error number is left in h_errno.
1664 *
1665 * Caller must parse answer and determine whether it answers the question.
1666 */
1667static int
1668res_queryN(name, target)
1669	const char *name;	/* domain name */
1670	struct res_target *target;
1671{
1672	u_char buf[MAXPACKET];
1673	HEADER *hp;
1674	int n;
1675	struct res_target *t;
1676	int rcode;
1677	int ancount;
1678
1679	rcode = NOERROR;
1680	ancount = 0;
1681
1682	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
1683		h_errno = NETDB_INTERNAL;
1684		return (-1);
1685	}
1686
1687	for (t = target; t; t = t->next) {
1688		int class, type;
1689		u_char *answer;
1690		int anslen;
1691
1692		hp = (HEADER *)(void *)t->answer;
1693		hp->rcode = NOERROR;	/* default */
1694
1695		/* make it easier... */
1696		class = t->qclass;
1697		type = t->qtype;
1698		answer = t->answer;
1699		anslen = t->anslen;
1700#ifdef DEBUG
1701		if (_res.options & RES_DEBUG)
1702			printf(";; res_query(%s, %d, %d)\n", name, class, type);
1703#endif
1704
1705		n = res_mkquery(QUERY, name, class, type, NULL, 0, NULL,
1706		    buf, sizeof(buf));
1707		if (n <= 0) {
1708#ifdef DEBUG
1709			if (_res.options & RES_DEBUG)
1710				printf(";; res_query: mkquery failed\n");
1711#endif
1712			h_errno = NO_RECOVERY;
1713			return (n);
1714		}
1715		n = res_send(buf, n, answer, anslen);
1716#if 0
1717		if (n < 0) {
1718#ifdef DEBUG
1719			if (_res.options & RES_DEBUG)
1720				printf(";; res_query: send error\n");
1721#endif
1722			h_errno = TRY_AGAIN;
1723			return (n);
1724		}
1725#endif
1726
1727		if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
1728			rcode = hp->rcode;	/* record most recent error */
1729#ifdef DEBUG
1730			if (_res.options & RES_DEBUG)
1731				printf(";; rcode = %d, ancount=%d\n", hp->rcode,
1732				    ntohs(hp->ancount));
1733#endif
1734			continue;
1735		}
1736
1737		ancount += ntohs(hp->ancount);
1738
1739		t->n = n;
1740	}
1741
1742	if (ancount == 0) {
1743		switch (rcode) {
1744		case NXDOMAIN:
1745			h_errno = HOST_NOT_FOUND;
1746			break;
1747		case SERVFAIL:
1748			h_errno = TRY_AGAIN;
1749			break;
1750		case NOERROR:
1751			h_errno = NO_DATA;
1752			break;
1753		case FORMERR:
1754		case NOTIMP:
1755		case REFUSED:
1756		default:
1757			h_errno = NO_RECOVERY;
1758			break;
1759		}
1760		return (-1);
1761	}
1762	return (ancount);
1763}
1764
1765/*
1766 * Formulate a normal query, send, and retrieve answer in supplied buffer.
1767 * Return the size of the response on success, -1 on error.
1768 * If enabled, implement search rules until answer or unrecoverable failure
1769 * is detected.  Error code, if any, is left in h_errno.
1770 */
1771static int
1772res_searchN(name, target)
1773	const char *name;	/* domain name */
1774	struct res_target *target;
1775{
1776	const char *cp, * const *domain;
1777	HEADER *hp = (HEADER *)(void *)target->answer;	/*XXX*/
1778	u_int dots;
1779	int trailing_dot, ret, saved_herrno;
1780	int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
1781
1782	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
1783		h_errno = NETDB_INTERNAL;
1784		return (-1);
1785	}
1786
1787	errno = 0;
1788	h_errno = HOST_NOT_FOUND;	/* default, if we never query */
1789	dots = 0;
1790	for (cp = name; *cp; cp++)
1791		dots += (*cp == '.');
1792	trailing_dot = 0;
1793	if (cp > name && *--cp == '.')
1794		trailing_dot++;
1795
1796	/*
1797	 * if there aren't any dots, it could be a user-level alias
1798	 */
1799	if (!dots && (cp = __hostalias(name)) != NULL)
1800		return (res_queryN(cp, target));
1801
1802	/*
1803	 * If there are dots in the name already, let's just give it a try
1804	 * 'as is'.  The threshold can be set with the "ndots" option.
1805	 */
1806	saved_herrno = -1;
1807	if (dots >= _res.ndots) {
1808		ret = res_querydomainN(name, NULL, target);
1809		if (ret > 0)
1810			return (ret);
1811		saved_herrno = h_errno;
1812		tried_as_is++;
1813	}
1814
1815	/*
1816	 * We do at least one level of search if
1817	 *	- there is no dot and RES_DEFNAME is set, or
1818	 *	- there is at least one dot, there is no trailing dot,
1819	 *	  and RES_DNSRCH is set.
1820	 */
1821	if ((!dots && (_res.options & RES_DEFNAMES)) ||
1822	    (dots && !trailing_dot && (_res.options & RES_DNSRCH))) {
1823		int done = 0;
1824
1825		for (domain = (const char * const *)_res.dnsrch;
1826		   *domain && !done;
1827		   domain++) {
1828
1829			ret = res_querydomainN(name, *domain, target);
1830			if (ret > 0)
1831				return (ret);
1832
1833			/*
1834			 * If no server present, give up.
1835			 * If name isn't found in this domain,
1836			 * keep trying higher domains in the search list
1837			 * (if that's enabled).
1838			 * On a NO_DATA error, keep trying, otherwise
1839			 * a wildcard entry of another type could keep us
1840			 * from finding this entry higher in the domain.
1841			 * If we get some other error (negative answer or
1842			 * server failure), then stop searching up,
1843			 * but try the input name below in case it's
1844			 * fully-qualified.
1845			 */
1846			if (errno == ECONNREFUSED) {
1847				h_errno = TRY_AGAIN;
1848				return (-1);
1849			}
1850
1851			switch (h_errno) {
1852			case NO_DATA:
1853				got_nodata++;
1854				/* FALLTHROUGH */
1855			case HOST_NOT_FOUND:
1856				/* keep trying */
1857				break;
1858			case TRY_AGAIN:
1859				if (hp->rcode == SERVFAIL) {
1860					/* try next search element, if any */
1861					got_servfail++;
1862					break;
1863				}
1864				/* FALLTHROUGH */
1865			default:
1866				/* anything else implies that we're done */
1867				done++;
1868			}
1869			/*
1870			 * if we got here for some reason other than DNSRCH,
1871			 * we only wanted one iteration of the loop, so stop.
1872			 */
1873			if (!(_res.options & RES_DNSRCH))
1874			        done++;
1875		}
1876	}
1877
1878	/*
1879	 * if we have not already tried the name "as is", do that now.
1880	 * note that we do this regardless of how many dots were in the
1881	 * name or whether it ends with a dot.
1882	 */
1883	if (!tried_as_is && (dots || !(_res.options & RES_NOTLDQUERY))) {
1884		ret = res_querydomainN(name, NULL, target);
1885		if (ret > 0)
1886			return (ret);
1887	}
1888
1889	/*
1890	 * if we got here, we didn't satisfy the search.
1891	 * if we did an initial full query, return that query's h_errno
1892	 * (note that we wouldn't be here if that query had succeeded).
1893	 * else if we ever got a nodata, send that back as the reason.
1894	 * else send back meaningless h_errno, that being the one from
1895	 * the last DNSRCH we did.
1896	 */
1897	if (saved_herrno != -1)
1898		h_errno = saved_herrno;
1899	else if (got_nodata)
1900		h_errno = NO_DATA;
1901	else if (got_servfail)
1902		h_errno = TRY_AGAIN;
1903	return (-1);
1904}
1905
1906/*
1907 * Perform a call on res_query on the concatenation of name and domain,
1908 * removing a trailing dot from name if domain is NULL.
1909 */
1910static int
1911res_querydomainN(name, domain, target)
1912	const char *name, *domain;
1913	struct res_target *target;
1914{
1915	char nbuf[MAXDNAME];
1916	const char *longname = nbuf;
1917	size_t n, d;
1918
1919	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
1920		h_errno = NETDB_INTERNAL;
1921		return (-1);
1922	}
1923#ifdef DEBUG
1924	if (_res.options & RES_DEBUG)
1925		printf(";; res_querydomain(%s, %s)\n",
1926			name, domain?domain:"<Nil>");
1927#endif
1928	if (domain == NULL) {
1929		/*
1930		 * Check for trailing '.';
1931		 * copy without '.' if present.
1932		 */
1933		n = strlen(name);
1934		if (n >= MAXDNAME) {
1935			h_errno = NO_RECOVERY;
1936			return (-1);
1937		}
1938		if (n > 0 && name[--n] == '.') {
1939			strncpy(nbuf, name, n);
1940			nbuf[n] = '\0';
1941		} else
1942			longname = name;
1943	} else {
1944		n = strlen(name);
1945		d = strlen(domain);
1946		if (n + d + 1 >= MAXDNAME) {
1947			h_errno = NO_RECOVERY;
1948			return (-1);
1949		}
1950		sprintf(nbuf, "%s.%s", name, domain);
1951	}
1952	return (res_queryN(longname, target));
1953}
1954