getaddrinfo.c revision 62836 
1/*	$FreeBSD: head/lib/libc/net/getaddrinfo.c 62836 2000-07-09 06:10:01Z itojun $	*/
2/*	$KAME: getaddrinfo.c,v 1.15 2000/07/09 04:37:24 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	char *ep;
363
364	if (*p == '\0')
365		return NO;
366	ep = NULL;
367	(void)strtoul(p, &ep, 10);
368	if (ep && *ep == '\0')
369		return YES;
370	else
371		return NO;
372}
373
374int
375getaddrinfo(hostname, servname, hints, res)
376	const char *hostname, *servname;
377	const struct addrinfo *hints;
378	struct addrinfo **res;
379{
380	struct addrinfo sentinel;
381	struct addrinfo *cur;
382	int error = 0;
383	struct addrinfo ai;
384	struct addrinfo ai0;
385	struct addrinfo *pai;
386	const struct explore *ex;
387
388	memset(&sentinel, 0, sizeof(sentinel));
389	cur = &sentinel;
390	pai = &ai;
391	pai->ai_flags = 0;
392	pai->ai_family = PF_UNSPEC;
393	pai->ai_socktype = ANY;
394	pai->ai_protocol = ANY;
395	pai->ai_addrlen = 0;
396	pai->ai_canonname = NULL;
397	pai->ai_addr = NULL;
398	pai->ai_next = NULL;
399
400	if (hostname == NULL && servname == NULL)
401		return EAI_NONAME;
402#ifdef EAI_RESNULL
403	if (res == NULL)
404		return EAI_RESNULL; /* xxx */
405#endif
406	if (hints) {
407		/* error check for hints */
408		if (hints->ai_addrlen || hints->ai_canonname ||
409		    hints->ai_addr || hints->ai_next)
410			ERR(EAI_BADHINTS); /* xxx */
411		if (hints->ai_flags & ~AI_MASK)
412			ERR(EAI_BADFLAGS);
413		switch (hints->ai_family) {
414		case PF_UNSPEC:
415		case PF_INET:
416#ifdef INET6
417		case PF_INET6:
418#endif
419			break;
420		default:
421			ERR(EAI_FAMILY);
422		}
423		memcpy(pai, hints, sizeof(*pai));
424
425		/*
426		 * if both socktype/protocol are specified, check if they
427		 * are meaningful combination.
428		 */
429		if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
430			for (ex = explore; ex->e_af >= 0; ex++) {
431				if (pai->ai_family != ex->e_af)
432					continue;
433				if (ex->e_socktype == ANY)
434					continue;
435				if (ex->e_protocol == ANY)
436					continue;
437				if (pai->ai_socktype == ex->e_socktype
438				 && pai->ai_protocol != ex->e_protocol) {
439					ERR(EAI_BADHINTS);
440				}
441			}
442		}
443	}
444
445	/*
446	 * post-2553: AI_ALL and AI_V4MAPPED are effective only against
447	 * AF_INET6 query.  They needs to be ignored if specified in other
448	 * occassions.
449	 */
450	switch (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) {
451	case AI_V4MAPPED:
452	case AI_ALL | AI_V4MAPPED:
453		if (pai->ai_family != AF_INET6)
454			pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
455		break;
456	case AI_ALL:
457#if 1
458		/* illegal */
459		ERR(EAI_BADFLAGS);
460#else
461		pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
462#endif
463		break;
464	}
465
466	/*
467	 * check for special cases.  (1) numeric servname is disallowed if
468	 * socktype/protocol are left unspecified. (2) servname is disallowed
469	 * for raw and other inet{,6} sockets.
470	 */
471	if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
472#ifdef PF_INET6
473	    || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
474#endif
475	    ) {
476		ai0 = *pai;	/* backup *pai */
477
478		if (pai->ai_family == PF_UNSPEC) {
479#ifdef PF_INET6
480			pai->ai_family = PF_INET6;
481#else
482			pai->ai_family = PF_INET;
483#endif
484		}
485		error = get_portmatch(pai, servname);
486		if (error)
487			ERR(error);
488
489		*pai = ai0;
490	}
491
492	ai0 = *pai;
493
494	/* NULL hostname, or numeric hostname */
495	for (ex = explore; ex->e_af >= 0; ex++) {
496		*pai = ai0;
497
498		/* PF_UNSPEC entries are prepared for DNS queries only */
499		if (ex->e_af == PF_UNSPEC)
500			continue;
501
502		if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
503			continue;
504		if (!MATCH(pai->ai_socktype, ex->e_socktype,
505			   WILD_SOCKTYPE(ex)))
506			continue;
507		if (!MATCH(pai->ai_protocol, ex->e_protocol,
508			   WILD_PROTOCOL(ex)))
509			continue;
510
511		if (pai->ai_family == PF_UNSPEC)
512			pai->ai_family = ex->e_af;
513		if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
514			pai->ai_socktype = ex->e_socktype;
515		if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
516			pai->ai_protocol = ex->e_protocol;
517
518		if (hostname == NULL)
519			error = explore_null(pai, servname, &cur->ai_next);
520		else
521			error = explore_numeric_scope(pai, hostname, servname,
522						      &cur->ai_next);
523
524		if (error)
525			goto free;
526
527		while (cur && cur->ai_next)
528			cur = cur->ai_next;
529	}
530
531	/*
532	 * XXX
533	 * If numreic representation of AF1 can be interpreted as FQDN
534	 * representation of AF2, we need to think again about the code below.
535	 */
536	if (sentinel.ai_next)
537		goto good;
538
539	if (pai->ai_flags & AI_NUMERICHOST)
540		ERR(EAI_NODATA);
541	if (hostname == NULL)
542		ERR(EAI_NODATA);
543
544#if 1
545	/* XXX: temporarily, behave as if AI_ADDRCONFIG is specified */
546	pai->ai_flags |= AI_ADDRCONFIG;
547#endif
548	if ((pai->ai_flags & AI_ADDRCONFIG) != 0 && !addrconfig(&ai0))
549		ERR(EAI_FAIL);
550
551	/*
552	 * hostname as alphabetical name.
553	 * we would like to prefer AF_INET6 than AF_INET, so we'll make a
554	 * outer loop by AFs.
555	 */
556	for (ex = explore; ex->e_af >= 0; ex++) {
557		*pai = ai0;
558
559		/* require exact match for family field */
560		if (pai->ai_family != ex->e_af)
561			continue;
562
563		if (!MATCH(pai->ai_socktype, ex->e_socktype,
564			   WILD_SOCKTYPE(ex))) {
565			continue;
566		}
567		if (!MATCH(pai->ai_protocol, ex->e_protocol,
568			   WILD_PROTOCOL(ex))) {
569			continue;
570		}
571
572		if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
573			pai->ai_socktype = ex->e_socktype;
574		if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
575			pai->ai_protocol = ex->e_protocol;
576
577		error = explore_fqdn(pai, hostname, servname, &cur->ai_next);
578
579		while (cur && cur->ai_next)
580			cur = cur->ai_next;
581	}
582
583	/* XXX */
584	if (sentinel.ai_next)
585		error = 0;
586
587	if (error)
588		goto free;
589	if (error == 0) {
590		if (sentinel.ai_next) {
591 good:
592			*res = sentinel.ai_next;
593			return SUCCESS;
594		} else
595			error = EAI_FAIL;
596	}
597 free:
598 bad:
599	if (sentinel.ai_next)
600		freeaddrinfo(sentinel.ai_next);
601	*res = NULL;
602	return error;
603}
604
605static char *
606_hgetword(char **pp)
607{
608	char c, *p, *ret;
609	const char *sp;
610	static const char sep[] = "# \t\n";
611
612	ret = NULL;
613	for (p = *pp; (c = *p) != '\0'; p++) {
614		for (sp = sep; *sp != '\0'; sp++) {
615			if (c == *sp)
616				break;
617		}
618		if (c == '#')
619			p[1] = '\0';	/* ignore rest of line */
620		if (ret == NULL) {
621			if (*sp == '\0')
622				ret = p;
623		} else {
624			if (*sp != '\0') {
625				*p++ = '\0';
626				break;
627			}
628		}
629	}
630	*pp = p;
631	if (ret == NULL || *ret == '\0')
632		return NULL;
633	return ret;
634}
635
636/*
637 * Initialize hostconf structure.
638 */
639
640static void
641_hostconf_init(void)
642{
643	FILE *fp;
644	int n;
645	char *p, *line;
646	char buf[BUFSIZ];
647
648	_hostconf_init_done = 1;
649	n = 0;
650	p = HOSTCONF;
651	if ((fp = fopen(p, "r")) == NULL)
652		return;
653	while (n < MAXHOSTCONF && fgets(buf, sizeof(buf), fp)) {
654		line = buf;
655		if ((p = _hgetword(&line)) == NULL)
656			continue;
657		do {
658			if (strcmp(p, "hosts") == 0
659			||  strcmp(p, "local") == 0
660			||  strcmp(p, "file") == 0
661			||  strcmp(p, "files") == 0)
662				_hostconf[n++].byname = _files_getaddrinfo;
663			else if (strcmp(p, "dns") == 0
664			     ||  strcmp(p, "bind") == 0)
665				_hostconf[n++].byname = _dns_getaddrinfo;
666#ifdef YP
667			else if (strcmp(p, "nis") == 0)
668				_hostconf[n++].byname = _nis_getaddrinfo;
669#endif
670		} while ((p = _hgetword(&line)) != NULL);
671	}
672	fclose(fp);
673	if (n < 0) {
674		/* no keyword found. do not change default configuration */
675		return;
676	}
677	for (; n < MAXHOSTCONF; n++)
678		_hostconf[n].byname = NULL;
679}
680
681/*
682 * FQDN hostname, DNS lookup
683 */
684static int
685explore_fqdn(pai, hostname, servname, res)
686	const struct addrinfo *pai;
687	const char *hostname;
688	const char *servname;
689	struct addrinfo **res;
690{
691	struct addrinfo *result;
692	struct addrinfo *cur;
693	int error = 0, i;
694
695	result = NULL;
696	*res = NULL;
697
698	/*
699	 * if the servname does not match socktype/protocol, ignore it.
700	 */
701	if (get_portmatch(pai, servname) != 0)
702		return 0;
703
704	if (!_hostconf_init_done)
705		_hostconf_init();
706
707	for (i = 0; i < MAXHOSTCONF; i++) {
708		if (!_hostconf[i].byname)
709			continue;
710		error = (*_hostconf[i].byname)(pai, hostname, &result);
711		if (error != 0)
712			continue;
713		for (cur = result; cur; cur = cur->ai_next) {
714			GET_PORT(cur, servname);
715			/* canonname should be filled already */
716		}
717		*res = result;
718		return 0;
719	}
720
721free:
722	if (result)
723		freeaddrinfo(result);
724	return error;
725}
726
727/*
728 * hostname == NULL.
729 * passive socket -> anyaddr (0.0.0.0 or ::)
730 * non-passive socket -> localhost (127.0.0.1 or ::1)
731 */
732static int
733explore_null(pai, servname, res)
734	const struct addrinfo *pai;
735	const char *servname;
736	struct addrinfo **res;
737{
738	int s;
739	const struct afd *afd;
740	struct addrinfo *cur;
741	struct addrinfo sentinel;
742	int error;
743
744	*res = NULL;
745	sentinel.ai_next = NULL;
746	cur = &sentinel;
747
748	/*
749	 * filter out AFs that are not supported by the kernel
750	 * XXX errno?
751	 */
752	s = socket(pai->ai_family, SOCK_DGRAM, 0);
753	if (s < 0) {
754		if (errno != EMFILE)
755			return 0;
756	} else
757		_close(s);
758
759	/*
760	 * if the servname does not match socktype/protocol, ignore it.
761	 */
762	if (get_portmatch(pai, servname) != 0)
763		return 0;
764
765	afd = find_afd(pai->ai_family);
766	if (afd == NULL)
767		return 0;
768
769	if (pai->ai_flags & AI_PASSIVE) {
770		GET_AI(cur->ai_next, afd, afd->a_addrany);
771		/* xxx meaningless?
772		 * GET_CANONNAME(cur->ai_next, "anyaddr");
773		 */
774		GET_PORT(cur->ai_next, servname);
775	} else {
776		GET_AI(cur->ai_next, afd, afd->a_loopback);
777		/* xxx meaningless?
778		 * GET_CANONNAME(cur->ai_next, "localhost");
779		 */
780		GET_PORT(cur->ai_next, servname);
781	}
782	cur = cur->ai_next;
783
784	*res = sentinel.ai_next;
785	return 0;
786
787free:
788	if (sentinel.ai_next)
789		freeaddrinfo(sentinel.ai_next);
790	return error;
791}
792
793/*
794 * numeric hostname
795 */
796static int
797explore_numeric(pai, hostname, servname, res)
798	const struct addrinfo *pai;
799	const char *hostname;
800	const char *servname;
801	struct addrinfo **res;
802{
803	const struct afd *afd;
804	struct addrinfo *cur;
805	struct addrinfo sentinel;
806	int error;
807	char pton[PTON_MAX];
808
809	*res = NULL;
810	sentinel.ai_next = NULL;
811	cur = &sentinel;
812
813	/*
814	 * if the servname does not match socktype/protocol, ignore it.
815	 */
816	if (get_portmatch(pai, servname) != 0)
817		return 0;
818
819	afd = find_afd(pai->ai_family);
820	if (afd == NULL)
821		return 0;
822
823	switch (afd->a_af) {
824#if 1 /*X/Open spec*/
825	case AF_INET:
826		if (inet_aton(hostname, (struct in_addr *)pton) == 1) {
827			if (pai->ai_family == afd->a_af ||
828			    pai->ai_family == PF_UNSPEC /*?*/) {
829				GET_AI(cur->ai_next, afd, pton);
830				GET_PORT(cur->ai_next, servname);
831				while (cur && cur->ai_next)
832					cur = cur->ai_next;
833			} else
834				ERR(EAI_FAMILY);	/*xxx*/
835		}
836		break;
837#endif
838	default:
839		if (inet_pton(afd->a_af, hostname, pton) == 1) {
840			if (pai->ai_family == afd->a_af ||
841			    pai->ai_family == PF_UNSPEC /*?*/) {
842				GET_AI(cur->ai_next, afd, pton);
843				GET_PORT(cur->ai_next, servname);
844				while (cur && cur->ai_next)
845					cur = cur->ai_next;
846			} else
847				ERR(EAI_FAMILY);	/*xxx*/
848		}
849		break;
850	}
851
852	*res = sentinel.ai_next;
853	return 0;
854
855free:
856bad:
857	if (sentinel.ai_next)
858		freeaddrinfo(sentinel.ai_next);
859	return error;
860}
861
862/*
863 * numeric hostname with scope
864 */
865static int
866explore_numeric_scope(pai, hostname, servname, res)
867	const struct addrinfo *pai;
868	const char *hostname;
869	const char *servname;
870	struct addrinfo **res;
871{
872#if !defined(SCOPE_DELIMITER) || !defined(INET6)
873	return explore_numeric(pai, hostname, servname, res);
874#else
875	const struct afd *afd;
876	struct addrinfo *cur;
877	int error;
878	char *cp, *hostname2 = NULL, *scope, *addr;
879	struct sockaddr_in6 *sin6;
880
881	/*
882	 * if the servname does not match socktype/protocol, ignore it.
883	 */
884	if (get_portmatch(pai, servname) != 0)
885		return 0;
886
887	afd = find_afd(pai->ai_family);
888	if (afd == NULL)
889		return 0;
890	if (!afd->a_scoped)
891		return explore_numeric(pai, hostname, servname, res);
892
893	cp = strchr(hostname, SCOPE_DELIMITER);
894	if (cp == NULL)
895		return explore_numeric(pai, hostname, servname, res);
896
897	/*
898	 * Handle special case of <scoped_address><delimiter><scope id>
899	 */
900	hostname2 = strdup(hostname);
901	if (hostname2 == NULL)
902		return EAI_MEMORY;
903	/* terminate at the delimiter */
904	hostname2[cp - hostname] = '\0';
905	addr = hostname2;
906	scope = cp + 1;
907
908	error = explore_numeric(pai, addr, servname, res);
909	if (error == 0) {
910		int scopeid;
911
912		for (cur = *res; cur; cur = cur->ai_next) {
913			if (cur->ai_family != AF_INET6)
914				continue;
915			sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
916			if ((scopeid = ip6_str2scopeid(scope, sin6)) == -1) {
917				free(hostname2);
918				return(EAI_NODATA); /* XXX: is return OK? */
919			}
920			sin6->sin6_scope_id = scopeid;
921		}
922	}
923
924	free(hostname2);
925
926	return error;
927#endif
928}
929
930static int
931get_canonname(pai, ai, str)
932	const struct addrinfo *pai;
933	struct addrinfo *ai;
934	const char *str;
935{
936	if ((pai->ai_flags & AI_CANONNAME) != 0) {
937		ai->ai_canonname = (char *)malloc(strlen(str) + 1);
938		if (ai->ai_canonname == NULL)
939			return EAI_MEMORY;
940		strcpy(ai->ai_canonname, str);
941	}
942	return 0;
943}
944
945static struct addrinfo *
946get_ai(pai, afd, addr)
947	const struct addrinfo *pai;
948	const struct afd *afd;
949	const char *addr;
950{
951	char *p;
952	struct addrinfo *ai;
953#ifdef FAITH
954	struct in6_addr faith_prefix;
955	char *fp_str;
956	int translate = 0;
957#endif
958
959#ifdef FAITH
960	/*
961	 * Transfrom an IPv4 addr into a special IPv6 addr format for
962	 * IPv6->IPv4 translation gateway. (only TCP is supported now)
963	 *
964	 * +-----------------------------------+------------+
965	 * | faith prefix part (12 bytes)      | embedded   |
966	 * |                                   | IPv4 addr part (4 bytes)
967	 * +-----------------------------------+------------+
968	 *
969	 * faith prefix part is specified as ascii IPv6 addr format
970	 * in environmental variable GAI.
971	 * For FAITH to work correctly, routing to faith prefix must be
972	 * setup toward a machine where a FAITH daemon operates.
973	 * Also, the machine must enable some mechanizm
974	 * (e.g. faith interface hack) to divert those packet with
975	 * faith prefixed destination addr to user-land FAITH daemon.
976	 */
977	fp_str = getenv("GAI");
978	if (fp_str && inet_pton(AF_INET6, fp_str, &faith_prefix) == 1 &&
979	    afd->a_af == AF_INET && pai->ai_socktype == SOCK_STREAM) {
980		u_int32_t v4a;
981		u_int8_t v4a_top;
982
983		memcpy(&v4a, addr, sizeof v4a);
984		v4a_top = v4a >> IN_CLASSA_NSHIFT;
985		if (!IN_MULTICAST(v4a) && !IN_EXPERIMENTAL(v4a) &&
986		    v4a_top != 0 && v4a != IN_LOOPBACKNET) {
987			afd = &afdl[N_INET6];
988			memcpy(&faith_prefix.s6_addr[12], addr,
989			       sizeof(struct in_addr));
990			translate = 1;
991		}
992	}
993#endif
994
995	ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
996		+ (afd->a_socklen));
997	if (ai == NULL)
998		return NULL;
999
1000	memcpy(ai, pai, sizeof(struct addrinfo));
1001	ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1002	memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
1003	ai->ai_addr->sa_len = afd->a_socklen;
1004	ai->ai_addrlen = afd->a_socklen;
1005	ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
1006	p = (char *)(ai->ai_addr);
1007#ifdef FAITH
1008	if (translate == 1)
1009		memcpy(p + afd->a_off, &faith_prefix, afd->a_addrlen);
1010	else
1011#endif
1012	memcpy(p + afd->a_off, addr, afd->a_addrlen);
1013
1014	return ai;
1015}
1016
1017static int
1018get_portmatch(ai, servname)
1019	const struct addrinfo *ai;
1020	const char *servname;
1021{
1022
1023	/* get_port does not touch first argument. when matchonly == 1. */
1024	/* LINTED const cast */
1025	return get_port((struct addrinfo *)ai, servname, 1);
1026}
1027
1028static int
1029get_port(ai, servname, matchonly)
1030	struct addrinfo *ai;
1031	const char *servname;
1032	int matchonly;
1033{
1034	const char *proto;
1035	struct servent *sp;
1036	int port;
1037	int allownumeric;
1038
1039	if (servname == NULL)
1040		return 0;
1041	switch (ai->ai_family) {
1042	case AF_INET:
1043#ifdef AF_INET6
1044	case AF_INET6:
1045#endif
1046		break;
1047	default:
1048		return 0;
1049	}
1050
1051	switch (ai->ai_socktype) {
1052	case SOCK_RAW:
1053		return EAI_SERVICE;
1054	case SOCK_DGRAM:
1055	case SOCK_STREAM:
1056		allownumeric = 1;
1057		break;
1058	case ANY:
1059		allownumeric = 0;
1060		break;
1061	default:
1062		return EAI_SOCKTYPE;
1063	}
1064
1065	if (str_isnumber(servname)) {
1066		if (!allownumeric)
1067			return EAI_SERVICE;
1068		port = htons(atoi(servname));
1069		if (port < 0 || port > 65535)
1070			return EAI_SERVICE;
1071	} else {
1072		switch (ai->ai_socktype) {
1073		case SOCK_DGRAM:
1074			proto = "udp";
1075			break;
1076		case SOCK_STREAM:
1077			proto = "tcp";
1078			break;
1079		default:
1080			proto = NULL;
1081			break;
1082		}
1083
1084		if ((sp = getservbyname(servname, proto)) == NULL)
1085			return EAI_SERVICE;
1086		port = sp->s_port;
1087	}
1088
1089	if (!matchonly) {
1090		switch (ai->ai_family) {
1091		case AF_INET:
1092			((struct sockaddr_in *)(void *)
1093			    ai->ai_addr)->sin_port = port;
1094			break;
1095#ifdef INET6
1096		case AF_INET6:
1097			((struct sockaddr_in6 *)(void *)
1098			    ai->ai_addr)->sin6_port = port;
1099			break;
1100#endif
1101		}
1102	}
1103
1104	return 0;
1105}
1106
1107static const struct afd *
1108find_afd(af)
1109	int af;
1110{
1111	const struct afd *afd;
1112
1113	if (af == PF_UNSPEC)
1114		return NULL;
1115	for (afd = afdl; afd->a_af; afd++) {
1116		if (afd->a_af == af)
1117			return afd;
1118	}
1119	return NULL;
1120}
1121
1122/*
1123 * post-2553: AI_ADDRCONFIG check.  if we use getipnodeby* as backend, backend
1124 * will take care of it.
1125 * the semantics of AI_ADDRCONFIG is not defined well.  we are not sure
1126 * if the code is right or not.
1127 *
1128 * XXX PF_UNSPEC -> PF_INET6 + PF_INET mapping needs to be in sync with
1129 * _dns_getaddrinfo.
1130 */
1131static int
1132addrconfig(pai)
1133	struct addrinfo *pai;
1134{
1135	int s, af;
1136
1137	/*
1138	 * TODO:
1139	 * Note that implementation dependent test for address
1140	 * configuration should be done everytime called
1141	 * (or apropriate interval),
1142	 * because addresses will be dynamically assigned or deleted.
1143	 */
1144	af = pai->ai_family;
1145	if (af == AF_UNSPEC) {
1146		if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
1147			af = AF_INET;
1148		else {
1149			close(s);
1150			if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
1151				af = AF_INET6;
1152			else
1153				close(s);
1154		}
1155
1156	}
1157	if (af != AF_UNSPEC) {
1158		if ((s = socket(af, SOCK_DGRAM, 0)) < 0)
1159			return 0;
1160		close(s);
1161	}
1162	pai->ai_family = af;
1163	return 1;
1164}
1165
1166#ifdef INET6
1167/* convert a string to a scope identifier. XXX: IPv6 specific */
1168static int
1169ip6_str2scopeid(scope, sin6)
1170	char *scope;
1171	struct sockaddr_in6 *sin6;
1172{
1173	int scopeid;
1174	struct in6_addr *a6 = &sin6->sin6_addr;
1175	char *ep;
1176
1177	/* empty scopeid portion is invalid */
1178	if (*scope == '\0')
1179		return -1;
1180
1181	if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) {
1182		/*
1183		 * We currently assume a one-to-one mapping between links
1184		 * and interfaces, so we simply use interface indices for
1185		 * like-local scopes.
1186		 */
1187		scopeid = if_nametoindex(scope);
1188		if (scopeid == 0)
1189			goto trynumeric;
1190		return(scopeid);
1191	}
1192
1193	/* still unclear about literal, allow numeric only - placeholder */
1194	if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
1195		goto trynumeric;
1196	if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
1197		goto trynumeric;
1198	else
1199		goto trynumeric;	/* global */
1200
1201	/* try to convert to a numeric id as a last resort */
1202  trynumeric:
1203	scopeid = (int)strtoul(scope, &ep, 10);
1204	if (*ep == '\0')
1205		return scopeid;
1206	else
1207		return -1;
1208}
1209#endif
1210
1211#ifdef DEBUG
1212static const char AskedForGot[] =
1213	"gethostby*.getanswer: asked for \"%s\", got \"%s\"";
1214#endif
1215
1216static struct addrinfo *
1217getanswer(answer, anslen, qname, qtype, pai)
1218	const querybuf *answer;
1219	int anslen;
1220	const char *qname;
1221	int qtype;
1222	const struct addrinfo *pai;
1223{
1224	struct addrinfo sentinel, *cur;
1225	struct addrinfo ai;
1226	const struct afd *afd;
1227	char *canonname;
1228	const HEADER *hp;
1229	const u_char *cp;
1230	int n;
1231	const u_char *eom;
1232	char *bp;
1233	int type, class, buflen, ancount, qdcount;
1234	int haveanswer, had_error;
1235	char tbuf[MAXDNAME];
1236	int (*name_ok) __P((const char *));
1237	char hostbuf[8*1024];
1238
1239	memset(&sentinel, 0, sizeof(sentinel));
1240	cur = &sentinel;
1241
1242	canonname = NULL;
1243	eom = answer->buf + anslen;
1244	switch (qtype) {
1245	case T_A:
1246	case T_AAAA:
1247	case T_ANY:	/*use T_ANY only for T_A/T_AAAA lookup*/
1248		name_ok = res_hnok;
1249		break;
1250	default:
1251		return (NULL);	/* XXX should be abort(); */
1252	}
1253	/*
1254	 * find first satisfactory answer
1255	 */
1256	hp = &answer->hdr;
1257	ancount = ntohs(hp->ancount);
1258	qdcount = ntohs(hp->qdcount);
1259	bp = hostbuf;
1260	buflen = sizeof hostbuf;
1261	cp = answer->buf + HFIXEDSZ;
1262	if (qdcount != 1) {
1263		h_errno = NO_RECOVERY;
1264		return (NULL);
1265	}
1266	n = dn_expand(answer->buf, eom, cp, bp, buflen);
1267	if ((n < 0) || !(*name_ok)(bp)) {
1268		h_errno = NO_RECOVERY;
1269		return (NULL);
1270	}
1271	cp += n + QFIXEDSZ;
1272	if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
1273		/* res_send() has already verified that the query name is the
1274		 * same as the one we sent; this just gets the expanded name
1275		 * (i.e., with the succeeding search-domain tacked on).
1276		 */
1277		n = strlen(bp) + 1;		/* for the \0 */
1278		if (n >= MAXHOSTNAMELEN) {
1279			h_errno = NO_RECOVERY;
1280			return (NULL);
1281		}
1282		canonname = bp;
1283		bp += n;
1284		buflen -= n;
1285		/* The qname can be abbreviated, but h_name is now absolute. */
1286		qname = canonname;
1287	}
1288	haveanswer = 0;
1289	had_error = 0;
1290	while (ancount-- > 0 && cp < eom && !had_error) {
1291		n = dn_expand(answer->buf, eom, cp, bp, buflen);
1292		if ((n < 0) || !(*name_ok)(bp)) {
1293			had_error++;
1294			continue;
1295		}
1296		cp += n;			/* name */
1297		type = _getshort(cp);
1298 		cp += INT16SZ;			/* type */
1299		class = _getshort(cp);
1300 		cp += INT16SZ + INT32SZ;	/* class, TTL */
1301		n = _getshort(cp);
1302		cp += INT16SZ;			/* len */
1303		if (class != C_IN) {
1304			/* XXX - debug? syslog? */
1305			cp += n;
1306			continue;		/* XXX - had_error++ ? */
1307		}
1308		if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
1309		    type == T_CNAME) {
1310			n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
1311			if ((n < 0) || !(*name_ok)(tbuf)) {
1312				had_error++;
1313				continue;
1314			}
1315			cp += n;
1316			/* Get canonical name. */
1317			n = strlen(tbuf) + 1;	/* for the \0 */
1318			if (n > buflen || n >= MAXHOSTNAMELEN) {
1319				had_error++;
1320				continue;
1321			}
1322			strcpy(bp, tbuf);
1323			canonname = bp;
1324			bp += n;
1325			buflen -= n;
1326			continue;
1327		}
1328		if (qtype == T_ANY) {
1329			if (!(type == T_A || type == T_AAAA)) {
1330				cp += n;
1331				continue;
1332			}
1333		} else if (type != qtype) {
1334#ifdef DEBUG
1335			if (type != T_KEY && type != T_SIG)
1336				syslog(LOG_NOTICE|LOG_AUTH,
1337	       "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
1338				       qname, p_class(C_IN), p_type(qtype),
1339				       p_type(type));
1340#endif
1341			cp += n;
1342			continue;		/* XXX - had_error++ ? */
1343		}
1344		switch (type) {
1345		case T_A:
1346		case T_AAAA:
1347			if (strcasecmp(canonname, bp) != 0) {
1348#ifdef DEBUG
1349				syslog(LOG_NOTICE|LOG_AUTH,
1350				       AskedForGot, canonname, bp);
1351#endif
1352				cp += n;
1353				continue;	/* XXX - had_error++ ? */
1354			}
1355			if (type == T_A && n != INADDRSZ) {
1356				cp += n;
1357				continue;
1358			}
1359			if (type == T_AAAA && n != IN6ADDRSZ) {
1360				cp += n;
1361				continue;
1362			}
1363#ifdef FILTER_V4MAPPED
1364			if (type == T_AAAA) {
1365				struct in6_addr in6;
1366				memcpy(&in6, cp, sizeof(in6));
1367				if (IN6_IS_ADDR_V4MAPPED(&in6)) {
1368					cp += n;
1369					continue;
1370				}
1371			}
1372#endif
1373			if (!haveanswer) {
1374				int nn;
1375
1376				canonname = bp;
1377				nn = strlen(bp) + 1;	/* for the \0 */
1378				bp += nn;
1379				buflen -= nn;
1380			}
1381
1382			/* don't overwrite pai */
1383			ai = *pai;
1384			ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
1385			afd = find_afd(ai.ai_family);
1386			if (afd == NULL) {
1387				cp += n;
1388				continue;
1389			}
1390			cur->ai_next = get_ai(&ai, afd, (const char *)cp);
1391			if (cur->ai_next == NULL)
1392				had_error++;
1393			while (cur && cur->ai_next)
1394				cur = cur->ai_next;
1395			cp += n;
1396			break;
1397		default:
1398			abort();
1399		}
1400		if (!had_error)
1401			haveanswer++;
1402	}
1403	if (haveanswer) {
1404		if (!canonname)
1405			(void)get_canonname(pai, sentinel.ai_next, qname);
1406		else
1407			(void)get_canonname(pai, sentinel.ai_next, canonname);
1408		h_errno = NETDB_SUCCESS;
1409		return sentinel.ai_next;
1410	}
1411
1412	h_errno = NO_RECOVERY;
1413	return NULL;
1414}
1415
1416/*ARGSUSED*/
1417static int
1418_dns_getaddrinfo(pai, hostname, res)
1419	const struct addrinfo *pai;
1420	const char *hostname;
1421	struct addrinfo **res;
1422{
1423	struct addrinfo *ai;
1424	querybuf buf, buf2;
1425	const char *name;
1426	struct addrinfo sentinel, *cur;
1427	struct res_target q, q2;
1428
1429	memset(&q, 0, sizeof(q2));
1430	memset(&q2, 0, sizeof(q2));
1431	memset(&sentinel, 0, sizeof(sentinel));
1432	cur = &sentinel;
1433
1434	switch (pai->ai_family) {
1435	case AF_UNSPEC:
1436		/* prefer IPv6 */
1437		q.qclass = C_IN;
1438		q.qtype = T_AAAA;
1439		q.answer = buf.buf;
1440		q.anslen = sizeof(buf);
1441		q.next = &q2;
1442		q2.qclass = C_IN;
1443		q2.qtype = T_A;
1444		q2.answer = buf2.buf;
1445		q2.anslen = sizeof(buf2);
1446		break;
1447	case AF_INET:
1448		q.qclass = C_IN;
1449		q.qtype = T_A;
1450		q.answer = buf.buf;
1451		q.anslen = sizeof(buf);
1452		break;
1453	case AF_INET6:
1454		q.qclass = C_IN;
1455		q.qtype = T_AAAA;
1456		q.answer = buf.buf;
1457		q.anslen = sizeof(buf);
1458		break;
1459	default:
1460		return EAI_FAIL;
1461	}
1462	if (res_searchN(hostname, &q) < 0)
1463		return EAI_NODATA;
1464	ai = getanswer(&buf, q.n, q.name, q.qtype, pai);
1465	if (ai) {
1466		cur->ai_next = ai;
1467		while (cur && cur->ai_next)
1468			cur = cur->ai_next;
1469	}
1470	if (q.next) {
1471		ai = getanswer(&buf2, q2.n, q2.name, q2.qtype, pai);
1472		if (ai)
1473			cur->ai_next = ai;
1474	}
1475	if (sentinel.ai_next == NULL)
1476		switch (h_errno) {
1477		case HOST_NOT_FOUND:
1478			return EAI_NODATA;
1479		case TRY_AGAIN:
1480			return EAI_AGAIN;
1481		default:
1482			return EAI_FAIL;
1483		}
1484	*res = sentinel.ai_next;
1485	return 0;
1486}
1487
1488static struct addrinfo *
1489_gethtent(hostf, name, pai)
1490	FILE *hostf;
1491	const char *name;
1492	const struct addrinfo *pai;
1493{
1494	char *p;
1495	char *cp, *tname, *cname;
1496	struct addrinfo hints, *res0, *res;
1497	int error;
1498	const char *addr;
1499	char hostbuf[8*1024];
1500
1501 again:
1502	if (!(p = fgets(hostbuf, sizeof hostbuf, hostf)))
1503		return (NULL);
1504	if (*p == '#')
1505		goto again;
1506	if (!(cp = strpbrk(p, "#\n")))
1507		goto again;
1508	*cp = '\0';
1509	if (!(cp = strpbrk(p, " \t")))
1510		goto again;
1511	*cp++ = '\0';
1512	addr = p;
1513	cname = NULL;
1514	/* if this is not something we're looking for, skip it. */
1515	while (cp && *cp) {
1516		if (*cp == ' ' || *cp == '\t') {
1517			cp++;
1518			continue;
1519		}
1520		tname = cp;
1521		if (cname == NULL)
1522			cname = cp;
1523		if ((cp = strpbrk(cp, " \t")) != NULL)
1524			*cp++ = '\0';
1525		if (strcasecmp(name, tname) == 0)
1526			goto found;
1527	}
1528	goto again;
1529
1530found:
1531	hints = *pai;
1532	hints.ai_flags = AI_NUMERICHOST;
1533	error = getaddrinfo(addr, NULL, &hints, &res0);
1534	if (error)
1535		goto again;
1536#ifdef FILTER_V4MAPPED
1537	/* XXX should check all items in the chain */
1538	if (res0->ai_family == AF_INET6 &&
1539	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)res0->ai_addr)->sin6_addr)) {
1540		freeaddrinfo(res0);
1541		goto again;
1542	}
1543#endif
1544	for (res = res0; res; res = res->ai_next) {
1545		/* cover it up */
1546		res->ai_flags = pai->ai_flags;
1547
1548		if (pai->ai_flags & AI_CANONNAME) {
1549			if (get_canonname(pai, res, cname) != 0) {
1550				freeaddrinfo(res0);
1551				goto again;
1552			}
1553		}
1554	}
1555	return res0;
1556}
1557
1558/*ARGSUSED*/
1559static int
1560_files_getaddrinfo(pai, hostname, res)
1561	const struct addrinfo *pai;
1562	const char *hostname;
1563	struct addrinfo **res;
1564{
1565	FILE *hostf;
1566	struct addrinfo sentinel, *cur;
1567	struct addrinfo *p;
1568
1569	sentinel.ai_next = NULL;
1570	cur = &sentinel;
1571
1572	if ((hostf = fopen(_PATH_HOSTS, "r")) == NULL)
1573		return EAI_FAIL;
1574	while ((p = _gethtent(hostf, hostname, pai)) != NULL) {
1575		cur->ai_next = p;
1576		while (cur && cur->ai_next)
1577			cur = cur->ai_next;
1578	}
1579	fclose(hostf);
1580
1581	if (!sentinel.ai_next)
1582		return EAI_NODATA;
1583
1584	*res = sentinel.ai_next;
1585	return 0;
1586}
1587
1588#ifdef YP
1589/*ARGSUSED*/
1590static int
1591_nis_getaddrinfo(pai, hostname, res)
1592	const struct addrinfo *pai;
1593	const char *hostname;
1594	struct addrinfo **res;
1595{
1596	struct hostent *hp;
1597	int h_error;
1598	int af;
1599	struct addrinfo sentinel, *cur;
1600	int i;
1601	const struct afd *afd;
1602	int error;
1603
1604	sentinel.ai_next = NULL;
1605	cur = &sentinel;
1606
1607	af = (pai->ai_family == AF_UNSPEC) ? AF_INET : pai->ai_family;
1608	if (af != AF_INET)
1609		return (EAI_ADDRFAMILY);
1610
1611	if ((hp = _gethostbynisname(hostname, af)) == NULL) {
1612		switch (errno) {
1613		/* XXX: should be filled in */
1614		default:
1615			error = EAI_FAIL;
1616			break;
1617		}
1618	} else if (hp->h_name == NULL ||
1619		   hp->h_name[0] == 0 || hp->h_addr_list[0] == NULL) {
1620		hp = NULL;
1621		error = EAI_FAIL;
1622	}
1623
1624	if (hp == NULL)
1625		return error;
1626
1627	for (i = 0; hp->h_addr_list[i] != NULL; i++) {
1628		if (hp->h_addrtype != af)
1629			continue;
1630
1631		afd = find_afd(hp->h_addrtype);
1632		if (afd == NULL)
1633			continue;
1634
1635		GET_AI(cur->ai_next, afd, hp->h_addr_list[i]);
1636		if ((pai->ai_flags & AI_CANONNAME) != 0) {
1637			/*
1638			 * RFC2553 says that ai_canonname will be set only for
1639			 * the first element.  we do it for all the elements,
1640			 * just for convenience.
1641			 */
1642			GET_CANONNAME(cur->ai_next, hp->h_name);
1643		}
1644
1645		while (cur && cur->ai_next)
1646			cur = cur->ai_next;
1647	}
1648
1649	*res = sentinel.ai_next;
1650	return 0;
1651
1652free:
1653	if (sentinel.ai_next)
1654		freeaddrinfo(sentinel.ai_next);
1655	return error;
1656}
1657#endif
1658
1659/* resolver logic */
1660
1661extern const char *__hostalias __P((const char *));
1662extern int h_errno;
1663
1664/*
1665 * Formulate a normal query, send, and await answer.
1666 * Returned answer is placed in supplied buffer "answer".
1667 * Perform preliminary check of answer, returning success only
1668 * if no error is indicated and the answer count is nonzero.
1669 * Return the size of the response on success, -1 on error.
1670 * Error number is left in h_errno.
1671 *
1672 * Caller must parse answer and determine whether it answers the question.
1673 */
1674static int
1675res_queryN(name, target)
1676	const char *name;	/* domain name */
1677	struct res_target *target;
1678{
1679	u_char buf[MAXPACKET];
1680	HEADER *hp;
1681	int n;
1682	struct res_target *t;
1683	int rcode;
1684	int ancount;
1685
1686	rcode = NOERROR;
1687	ancount = 0;
1688
1689	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
1690		h_errno = NETDB_INTERNAL;
1691		return (-1);
1692	}
1693
1694	for (t = target; t; t = t->next) {
1695		int class, type;
1696		u_char *answer;
1697		int anslen;
1698
1699		hp = (HEADER *)(void *)t->answer;
1700		hp->rcode = NOERROR;	/* default */
1701
1702		/* make it easier... */
1703		class = t->qclass;
1704		type = t->qtype;
1705		answer = t->answer;
1706		anslen = t->anslen;
1707#ifdef DEBUG
1708		if (_res.options & RES_DEBUG)
1709			printf(";; res_query(%s, %d, %d)\n", name, class, type);
1710#endif
1711
1712		n = res_mkquery(QUERY, name, class, type, NULL, 0, NULL,
1713		    buf, sizeof(buf));
1714		if (n <= 0) {
1715#ifdef DEBUG
1716			if (_res.options & RES_DEBUG)
1717				printf(";; res_query: mkquery failed\n");
1718#endif
1719			h_errno = NO_RECOVERY;
1720			return (n);
1721		}
1722		n = res_send(buf, n, answer, anslen);
1723#if 0
1724		if (n < 0) {
1725#ifdef DEBUG
1726			if (_res.options & RES_DEBUG)
1727				printf(";; res_query: send error\n");
1728#endif
1729			h_errno = TRY_AGAIN;
1730			return (n);
1731		}
1732#endif
1733
1734		if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
1735			rcode = hp->rcode;	/* record most recent error */
1736#ifdef DEBUG
1737			if (_res.options & RES_DEBUG)
1738				printf(";; rcode = %d, ancount=%d\n", hp->rcode,
1739				    ntohs(hp->ancount));
1740#endif
1741			continue;
1742		}
1743
1744		ancount += ntohs(hp->ancount);
1745
1746		t->n = n;
1747	}
1748
1749	if (ancount == 0) {
1750		switch (rcode) {
1751		case NXDOMAIN:
1752			h_errno = HOST_NOT_FOUND;
1753			break;
1754		case SERVFAIL:
1755			h_errno = TRY_AGAIN;
1756			break;
1757		case NOERROR:
1758			h_errno = NO_DATA;
1759			break;
1760		case FORMERR:
1761		case NOTIMP:
1762		case REFUSED:
1763		default:
1764			h_errno = NO_RECOVERY;
1765			break;
1766		}
1767		return (-1);
1768	}
1769	return (ancount);
1770}
1771
1772/*
1773 * Formulate a normal query, send, and retrieve answer in supplied buffer.
1774 * Return the size of the response on success, -1 on error.
1775 * If enabled, implement search rules until answer or unrecoverable failure
1776 * is detected.  Error code, if any, is left in h_errno.
1777 */
1778static int
1779res_searchN(name, target)
1780	const char *name;	/* domain name */
1781	struct res_target *target;
1782{
1783	const char *cp, * const *domain;
1784	HEADER *hp = (HEADER *)(void *)target->answer;	/*XXX*/
1785	u_int dots;
1786	int trailing_dot, ret, saved_herrno;
1787	int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
1788
1789	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
1790		h_errno = NETDB_INTERNAL;
1791		return (-1);
1792	}
1793
1794	errno = 0;
1795	h_errno = HOST_NOT_FOUND;	/* default, if we never query */
1796	dots = 0;
1797	for (cp = name; *cp; cp++)
1798		dots += (*cp == '.');
1799	trailing_dot = 0;
1800	if (cp > name && *--cp == '.')
1801		trailing_dot++;
1802
1803	/*
1804	 * if there aren't any dots, it could be a user-level alias
1805	 */
1806	if (!dots && (cp = __hostalias(name)) != NULL)
1807		return (res_queryN(cp, target));
1808
1809	/*
1810	 * If there are dots in the name already, let's just give it a try
1811	 * 'as is'.  The threshold can be set with the "ndots" option.
1812	 */
1813	saved_herrno = -1;
1814	if (dots >= _res.ndots) {
1815		ret = res_querydomainN(name, NULL, target);
1816		if (ret > 0)
1817			return (ret);
1818		saved_herrno = h_errno;
1819		tried_as_is++;
1820	}
1821
1822	/*
1823	 * We do at least one level of search if
1824	 *	- there is no dot and RES_DEFNAME is set, or
1825	 *	- there is at least one dot, there is no trailing dot,
1826	 *	  and RES_DNSRCH is set.
1827	 */
1828	if ((!dots && (_res.options & RES_DEFNAMES)) ||
1829	    (dots && !trailing_dot && (_res.options & RES_DNSRCH))) {
1830		int done = 0;
1831
1832		for (domain = (const char * const *)_res.dnsrch;
1833		   *domain && !done;
1834		   domain++) {
1835
1836			ret = res_querydomainN(name, *domain, target);
1837			if (ret > 0)
1838				return (ret);
1839
1840			/*
1841			 * If no server present, give up.
1842			 * If name isn't found in this domain,
1843			 * keep trying higher domains in the search list
1844			 * (if that's enabled).
1845			 * On a NO_DATA error, keep trying, otherwise
1846			 * a wildcard entry of another type could keep us
1847			 * from finding this entry higher in the domain.
1848			 * If we get some other error (negative answer or
1849			 * server failure), then stop searching up,
1850			 * but try the input name below in case it's
1851			 * fully-qualified.
1852			 */
1853			if (errno == ECONNREFUSED) {
1854				h_errno = TRY_AGAIN;
1855				return (-1);
1856			}
1857
1858			switch (h_errno) {
1859			case NO_DATA:
1860				got_nodata++;
1861				/* FALLTHROUGH */
1862			case HOST_NOT_FOUND:
1863				/* keep trying */
1864				break;
1865			case TRY_AGAIN:
1866				if (hp->rcode == SERVFAIL) {
1867					/* try next search element, if any */
1868					got_servfail++;
1869					break;
1870				}
1871				/* FALLTHROUGH */
1872			default:
1873				/* anything else implies that we're done */
1874				done++;
1875			}
1876			/*
1877			 * if we got here for some reason other than DNSRCH,
1878			 * we only wanted one iteration of the loop, so stop.
1879			 */
1880			if (!(_res.options & RES_DNSRCH))
1881			        done++;
1882		}
1883	}
1884
1885	/*
1886	 * if we have not already tried the name "as is", do that now.
1887	 * note that we do this regardless of how many dots were in the
1888	 * name or whether it ends with a dot.
1889	 */
1890	if (!tried_as_is && (dots || !(_res.options & RES_NOTLDQUERY))) {
1891		ret = res_querydomainN(name, NULL, target);
1892		if (ret > 0)
1893			return (ret);
1894	}
1895
1896	/*
1897	 * if we got here, we didn't satisfy the search.
1898	 * if we did an initial full query, return that query's h_errno
1899	 * (note that we wouldn't be here if that query had succeeded).
1900	 * else if we ever got a nodata, send that back as the reason.
1901	 * else send back meaningless h_errno, that being the one from
1902	 * the last DNSRCH we did.
1903	 */
1904	if (saved_herrno != -1)
1905		h_errno = saved_herrno;
1906	else if (got_nodata)
1907		h_errno = NO_DATA;
1908	else if (got_servfail)
1909		h_errno = TRY_AGAIN;
1910	return (-1);
1911}
1912
1913/*
1914 * Perform a call on res_query on the concatenation of name and domain,
1915 * removing a trailing dot from name if domain is NULL.
1916 */
1917static int
1918res_querydomainN(name, domain, target)
1919	const char *name, *domain;
1920	struct res_target *target;
1921{
1922	char nbuf[MAXDNAME];
1923	const char *longname = nbuf;
1924	size_t n, d;
1925
1926	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
1927		h_errno = NETDB_INTERNAL;
1928		return (-1);
1929	}
1930#ifdef DEBUG
1931	if (_res.options & RES_DEBUG)
1932		printf(";; res_querydomain(%s, %s)\n",
1933			name, domain?domain:"<Nil>");
1934#endif
1935	if (domain == NULL) {
1936		/*
1937		 * Check for trailing '.';
1938		 * copy without '.' if present.
1939		 */
1940		n = strlen(name);
1941		if (n >= MAXDNAME) {
1942			h_errno = NO_RECOVERY;
1943			return (-1);
1944		}
1945		if (n > 0 && name[--n] == '.') {
1946			strncpy(nbuf, name, n);
1947			nbuf[n] = '\0';
1948		} else
1949			longname = name;
1950	} else {
1951		n = strlen(name);
1952		d = strlen(domain);
1953		if (n + d + 1 >= MAXDNAME) {
1954			h_errno = NO_RECOVERY;
1955			return (-1);
1956		}
1957		sprintf(nbuf, "%s.%s", name, domain);
1958	}
1959	return (res_queryN(longname, target));
1960}
1961