xref: /titanic_52/usr/src/lib/libresolv2/common/irs/getaddrinfo.c (revision a93a1f58a8763fa69172980b98e3d24720c1136e)
1 /*
2  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 
6 /*	$KAME: getaddrinfo.c,v 1.14 2001/01/06 09:41:15 jinmei Exp $	*/
7 
8 /*
9  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the project nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 /*
38  * Issues to be discussed:
39  * - Thread safe-ness must be checked.
40  * - Return values.  There are nonstandard return values defined and used
41  *   in the source code.  This is because RFC2553 is silent about which error
42  *   code must be returned for which situation.
43  * - IPv4 classful (shortened) form.  RFC2553 is silent about it.  XNET 5.2
44  *   says to use inet_aton() to convert IPv4 numeric to binary (allows
45  *   classful form as a result).
46  *   current code - disallow classful form for IPv4 (due to use of inet_pton).
47  * - freeaddrinfo(NULL).  RFC2553 is silent about it.  XNET 5.2 says it is
48  *   invalid.
49  *   current code - SEGV on freeaddrinfo(NULL)
50  * Note:
51  * - We use getipnodebyname() just for thread-safeness.  There's no intent
52  *   to let it do PF_UNSPEC (actually we never pass PF_UNSPEC to
53  *   getipnodebyname().
54  * - The code filters out AFs that are not supported by the kernel,
55  *   when globbing NULL hostname (to loopback, or wildcard).  Is it the right
56  *   thing to do?  What is the relationship with post-RFC2553 AI_ADDRCONFIG
57  *   in ai_flags?
58  * - (post-2553) semantics of AI_ADDRCONFIG itself is too vague.
59  *   (1) what should we do against numeric hostname (2) what should we do
60  *   against NULL hostname (3) what is AI_ADDRCONFIG itself.  AF not ready?
61  *   non-loopback address configured?  global address configured?
62  * - To avoid search order issue, we have a big amount of code duplicate
63  *   from gethnamaddr.c and some other places.  The issues that there's no
64  *   lower layer function to lookup "IPv4 or IPv6" record.  Calling
65  *   gethostbyname2 from getaddrinfo will end up in wrong search order, as
66  *   follows:
67  *	- The code makes use of following calls when asked to resolver with
68  *	  ai_family  = PF_UNSPEC:
69  *		getipnodebyname(host, AF_INET6);
70  *		getipnodebyname(host, AF_INET);
71  *	  This will result in the following queries if the node is configure to
72  *	  prefer /etc/hosts than DNS:
73  *		lookup /etc/hosts for IPv6 address
74  *		lookup DNS for IPv6 address
75  *		lookup /etc/hosts for IPv4 address
76  *		lookup DNS for IPv4 address
77  *	  which may not meet people's requirement.
78  *	  The right thing to happen is to have underlying layer which does
79  *	  PF_UNSPEC lookup (lookup both) and return chain of addrinfos.
80  *	  This would result in a bit of code duplicate with _dns_ghbyname() and
81  *	  friends.
82  */
83 
84 #pragma ident	"%Z%%M%	%I%	%E% SMI"
85 
86 #include "port_before.h"
87 
88 #include <sys/types.h>
89 #include <sys/param.h>
90 #include <sys/socket.h>
91 
92 #include <net/if.h>
93 #include <netinet/in.h>
94 
95 #include <arpa/inet.h>
96 #include <arpa/nameser.h>
97 
98 #include <netdb.h>
99 #include <resolv.h>
100 #include <string.h>
101 #include <stdlib.h>
102 #include <stddef.h>
103 #include <ctype.h>
104 #include <unistd.h>
105 #include <stdio.h>
106 #include <errno.h>
107 
108 #include <stdarg.h>
109 
110 #include <irs.h>
111 #include <isc/assertions.h>
112 
113 #include "port_after.h"
114 
115 #include "irs_data.h"
116 
117 #define SUCCESS 0
118 #define ANY 0
119 #define YES 1
120 #define NO  0
121 
122 static const char in_addrany[] = { 0, 0, 0, 0 };
123 static const char in6_addrany[] = {
124 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
125 };
126 static const char in_loopback[] = { 127, 0, 0, 1 };
127 static const char in6_loopback[] = {
128 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
129 };
130 
131 static const struct afd {
132 	int a_af;
133 	int a_addrlen;
134 	int a_socklen;
135 	int a_off;
136 	const char *a_addrany;
137 	const char *a_loopback;
138 	int a_scoped;
139 } afdl [] = {
140 	{PF_INET6, sizeof(struct in6_addr),
141 	 sizeof(struct sockaddr_in6),
142 	 offsetof(struct sockaddr_in6, sin6_addr),
143 	 in6_addrany, in6_loopback, 1},
144 	{PF_INET, sizeof(struct in_addr),
145 	 sizeof(struct sockaddr_in),
146 	 offsetof(struct sockaddr_in, sin_addr),
147 	 in_addrany, in_loopback, 0},
148 	{0, 0, 0, 0, NULL, NULL, 0},
149 };
150 
151 struct explore {
152 	int e_af;
153 	int e_socktype;
154 	int e_protocol;
155 	const char *e_protostr;
156 	int e_wild;
157 #define WILD_AF(ex)		((ex)->e_wild & 0x01)
158 #define WILD_SOCKTYPE(ex)	((ex)->e_wild & 0x02)
159 #define WILD_PROTOCOL(ex)	((ex)->e_wild & 0x04)
160 };
161 
162 static const struct explore explore[] = {
163 #if 0
164 	{ PF_LOCAL, 0, ANY, ANY, NULL, 0x01 },
165 #endif
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 	{ PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
170 	{ PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
171 	{ PF_INET, SOCK_RAW, ANY, NULL, 0x05 },
172 	{ -1, 0, 0, NULL, 0 },
173 };
174 
175 #define PTON_MAX	16
176 
177 static int str_isnumber __P((const char *));
178 static int explore_fqdn __P((const struct addrinfo *, const char *,
179 	const char *, struct addrinfo **));
180 static int explore_copy __P((const struct addrinfo *, const struct addrinfo *,
181 	struct addrinfo **));
182 static int explore_null __P((const struct addrinfo *,
183 	const char *, struct addrinfo **));
184 static int explore_numeric __P((const struct addrinfo *, const char *,
185 	const char *, struct addrinfo **));
186 static int explore_numeric_scope __P((const struct addrinfo *, const char *,
187 	const char *, struct addrinfo **));
188 static int get_canonname __P((const struct addrinfo *,
189 	struct addrinfo *, const char *));
190 static struct addrinfo *get_ai __P((const struct addrinfo *,
191 	const struct afd *, const char *));
192 static struct addrinfo *copy_ai __P((const struct addrinfo *));
193 static int get_portmatch __P((const struct addrinfo *, const char *));
194 static int get_port __P((const struct addrinfo *, const char *, int));
195 static const struct afd *find_afd __P((int));
196 static int addrconfig __P((int));
197 static int ip6_str2scopeid __P((char *, struct sockaddr_in6 *,
198 				u_int32_t *scopeidp));
199 static struct net_data *init __P((void));
200 
201 struct addrinfo *hostent2addrinfo __P((struct hostent *,
202 				       const struct addrinfo *));
203 struct addrinfo *addr2addrinfo __P((const struct addrinfo *,
204 				    const char *));
205 
206 #if 0
207 static const char *ai_errlist[] = {
208 	"Success",
209 	"Address family for hostname not supported",	/* EAI_ADDRFAMILY */
210 	"Temporary failure in name resolution",		/* EAI_AGAIN      */
211 	"Invalid value for ai_flags",		       	/* EAI_BADFLAGS   */
212 	"Non-recoverable failure in name resolution", 	/* EAI_FAIL       */
213 	"ai_family not supported",			/* EAI_FAMILY     */
214 	"Memory allocation failure", 			/* EAI_MEMORY     */
215 	"No address associated with hostname", 		/* EAI_NODATA     */
216 	"hostname nor servname provided, or not known",	/* EAI_NONAME     */
217 	"servname not supported for ai_socktype",	/* EAI_SERVICE    */
218 	"ai_socktype not supported", 			/* EAI_SOCKTYPE   */
219 	"System error returned in errno", 		/* EAI_SYSTEM     */
220 	"Invalid value for hints",			/* EAI_BADHINTS	  */
221 	"Resolved protocol is unknown",			/* EAI_PROTOCOL   */
222 	"Unknown error", 				/* EAI_MAX        */
223 };
224 #endif
225 
226 /* XXX macros that make external reference is BAD. */
227 
228 #define GET_AI(ai, afd, addr) \
229 do { \
230 	/* external reference: pai, error, and label free */ \
231 	(ai) = get_ai(pai, (afd), (addr)); \
232 	if ((ai) == NULL) { \
233 		error = EAI_MEMORY; \
234 		goto free; \
235 	} \
236 } while (/*CONSTCOND*/0)
237 
238 #define GET_PORT(ai, serv) \
239 do { \
240 	/* external reference: error and label free */ \
241 	error = get_port((ai), (serv), 0); \
242 	if (error != 0) \
243 		goto free; \
244 } while (/*CONSTCOND*/0)
245 
246 #define GET_CANONNAME(ai, str) \
247 do { \
248 	/* external reference: pai, error and label free */ \
249 	error = get_canonname(pai, (ai), (str)); \
250 	if (error != 0) \
251 		goto free; \
252 } while (/*CONSTCOND*/0)
253 
254 /*
255  * Our compiler does not like an unconditional branch out of a loop,
256  * especially one defined in a macro!
257  */
258 #ifdef ORIGINAL_ISC_CODE
259 #define ERR(err) \
260 do { \
261 	/* external reference: error, and label bad */ \
262 	error = (err); \
263 	goto bad; \
264 	/*NOTREACHED*/ \
265 } while (/*CONSTCOND*/0)
266 #else
267 #define ERR(err) \
268 do { \
269 	/* external reference: error */ \
270 	error = (err); \
271 	/*NOTREACHED*/ \
272 } while (/*CONSTCOND*/0)
273 #endif
274 
275 #define MATCH_FAMILY(x, y, w) \
276 	((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || (y) == PF_UNSPEC)))
277 #define MATCH(x, y, w) \
278 	((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY)))
279 
280 #if 0				/* bind8 has its own version */
281 char *
282 gai_strerror(ecode)
283 	int ecode;
284 {
285 	if (ecode < 0 || ecode > EAI_MAX)
286 		ecode = EAI_MAX;
287 	return ai_errlist[ecode];
288 }
289 #endif
290 
291 void
292 freeaddrinfo(ai)
293 	struct addrinfo *ai;
294 {
295 	struct addrinfo *next;
296 
297 	do {
298 		next = ai->ai_next;
299 		if (ai->ai_canonname)
300 			free(ai->ai_canonname);
301 		/* no need to free(ai->ai_addr) */
302 		free(ai);
303 		ai = next;
304 	} while (ai);
305 }
306 
307 static int
308 str_isnumber(p)
309 	const char *p;
310 {
311 	char *ep;
312 
313 	if (*p == '\0')
314 		return NO;
315 	ep = NULL;
316 	errno = 0;
317 	(void)strtoul(p, &ep, 10);
318 	if (errno == 0 && ep && *ep == '\0')
319 		return YES;
320 	else
321 		return NO;
322 }
323 
324 int
325 getaddrinfo(hostname, servname, hints, res)
326 	const char *hostname, *servname;
327 	const struct addrinfo *hints;
328 	struct addrinfo **res;
329 {
330 	struct addrinfo sentinel;
331 	struct addrinfo *cur;
332 	int error = 0;
333 	struct addrinfo ai, ai0, *afai = NULL;
334 	struct addrinfo *pai;
335 	const struct explore *ex;
336 
337 	memset(&sentinel, 0, sizeof(sentinel));
338 	cur = &sentinel;
339 	pai = &ai;
340 	pai->ai_flags = 0;
341 	pai->ai_family = PF_UNSPEC;
342 	pai->ai_socktype = ANY;
343 	pai->ai_protocol = ANY;
344 #ifndef ORIGINAL_ISC_CODE
345 #ifdef __sparcv9
346 	/*
347 	 * We need to clear _ai_pad to preserve binary
348 	 * compatibility with previously compiled 64-bit
349 	 * applications in a pre-SUSv3 environment by
350 	 * guaranteeing the upper 32-bits are empty.
351 	 */
352 	pai->_ai_pad = 0;
353 #endif /* __sparcv9 */
354 #endif /* ORIGINAL_ISC_CODE */
355 	pai->ai_addrlen = 0;
356 	pai->ai_canonname = NULL;
357 	pai->ai_addr = NULL;
358 	pai->ai_next = NULL;
359 
360 	if (hostname == NULL && servname == NULL)
361 		return EAI_NONAME;
362 	if (hints) {
363 		/* error check for hints */
364 		if (hints->ai_addrlen || hints->ai_canonname ||
365 		    hints->ai_addr || hints->ai_next) {
366 			ERR(EAI_BADHINTS); /* xxx */
367 #if !defined(ORIGINAL_ISC_CODE)
368 			goto bad;
369 #endif
370 		}
371 /*
372  * The AI_ macros defined by ISC are different than those defined by Solaris.
373  * AI_MASK is defined by ISC to check the range of their flags and doesn't work
374  * with Solaris.
375  */
376 #ifdef ORIGINAL_ISC_CODE
377 		if (hints->ai_flags & ~AI_MASK) {
378 			ERR(EAI_BADFLAGS);
379 		}
380 #endif
381 		switch (hints->ai_family) {
382 		case PF_UNSPEC:
383 		case PF_INET:
384 		case PF_INET6:
385 			break;
386 		default:
387 			ERR(EAI_FAMILY);
388 #if !defined(ORIGINAL_ISC_CODE)
389 			goto bad;
390 #endif
391 		}
392 		memcpy(pai, hints, sizeof(*pai));
393 
394 #ifndef ORIGINAL_ISC_CODE
395 #ifdef __sparcv9
396 		/*
397 		 * We need to clear _ai_pad to preserve binary
398 		 * compatibility.  See prior comment.
399 		 */
400 		pai->_ai_pad = 0;
401 #endif /* __sparcv9 */
402 #endif /* ORIGINAL_ISC_CODE */
403 		/*
404 		 * if both socktype/protocol are specified, check if they
405 		 * are meaningful combination.
406 		 */
407 		if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
408 			for (ex = explore; ex->e_af >= 0; ex++) {
409 				if (pai->ai_family != ex->e_af)
410 					continue;
411 				if (ex->e_socktype == ANY)
412 					continue;
413 				if (ex->e_protocol == ANY)
414 					continue;
415 				if (pai->ai_socktype == ex->e_socktype &&
416 				    pai->ai_protocol != ex->e_protocol) {
417 					ERR(EAI_BADHINTS);
418 #if !defined(ORIGINAL_ISC_CODE)
419 					goto bad;
420 #endif
421 				}
422 			}
423 		}
424 	}
425 
426 	/*
427 	 * post-2553: AI_ALL and AI_V4MAPPED are effective only against
428 	 * AF_INET6 query.  They needs to be ignored if specified in other
429 	 * occassions.
430 	 */
431 	switch (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) {
432 	case AI_V4MAPPED:
433 	case AI_ALL | AI_V4MAPPED:
434 		if (pai->ai_family != AF_INET6)
435 			pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
436 		break;
437 	case AI_ALL:
438 #if 1
439 		/* illegal */
440 		ERR(EAI_BADFLAGS);
441 #if !defined(ORIGINAL_ISC_CODE)
442 		goto bad;
443 #endif
444 #else
445 		pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
446 		break;
447 #endif
448 	}
449 
450 	/*
451 	 * check for special cases.  (1) numeric servname is disallowed if
452 	 * socktype/protocol are left unspecified. (2) servname is disallowed
453 	 * for raw and other inet{,6} sockets.
454 	 */
455 	if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
456 #ifdef PF_INET6
457 	 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
458 #endif
459 	    ) {
460 		ai0 = *pai;	/* backup *pai */
461 
462 		if (pai->ai_family == PF_UNSPEC) {
463 #ifdef PF_INET6
464 			pai->ai_family = PF_INET6;
465 #else
466 			pai->ai_family = PF_INET;
467 #endif
468 		}
469 		error = get_portmatch(pai, servname);
470 		if (error) {
471 			ERR(error);
472 #if !defined(ORIGINAL_ISC_CODE)
473 			goto bad;
474 #endif
475 		}
476 
477 		*pai = ai0;
478 	}
479 
480 	ai0 = *pai;
481 
482 	/* NULL hostname, or numeric hostname */
483 	for (ex = explore; ex->e_af >= 0; ex++) {
484 		*pai = ai0;
485 
486 		if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
487 			continue;
488 		if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex)))
489 			continue;
490 		if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex)))
491 			continue;
492 
493 		if (pai->ai_family == PF_UNSPEC)
494 			pai->ai_family = ex->e_af;
495 		if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
496 			pai->ai_socktype = ex->e_socktype;
497 		if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
498 			pai->ai_protocol = ex->e_protocol;
499 
500 		/*
501 		 * if the servname does not match socktype/protocol, ignore it.
502 		 */
503 		if (get_portmatch(pai, servname) != 0)
504 			continue;
505 
506 		if (hostname == NULL) {
507 			/*
508 			 * filter out AFs that are not supported by the kernel
509 			 * XXX errno?
510 			 */
511 			if (!addrconfig(pai->ai_family))
512 				continue;
513 			error = explore_null(pai, servname, &cur->ai_next);
514 		} else
515 			error = explore_numeric_scope(pai, hostname, servname,
516 			    &cur->ai_next);
517 
518 		if (error)
519 			goto free;
520 
521 		while (cur && cur->ai_next)
522 			cur = cur->ai_next;
523 	}
524 
525 	/*
526 	 * XXX
527 	 * If numreic representation of AF1 can be interpreted as FQDN
528 	 * representation of AF2, we need to think again about the code below.
529 	 */
530 	if (sentinel.ai_next)
531 		goto good;
532 
533 	if (pai->ai_flags & AI_NUMERICHOST) {
534 		ERR(EAI_NONAME);
535 #if !defined(ORIGINAL_ISC_CODE)
536 		goto bad;
537 #endif
538 	}
539 	if (hostname == NULL) {
540 		ERR(EAI_NONAME);
541 #if !defined(ORIGINAL_ISC_CODE)
542 		goto bad;
543 #endif
544 	}
545 
546 	/*
547 	 * hostname as alphabetical name.
548 	 * We'll make sure that
549 	 * - if returning addrinfo list is empty, return non-zero error
550 	 *   value (already known one or EAI_NONAME).
551 	 * - otherwise,
552 	 *   + if we haven't had any errors, return 0 (i.e. success).
553 	 *   + if we've had an error, free the list and return the error.
554 	 * without any assumption on the behavior of explore_fqdn().
555 	 */
556 
557 	/* first, try to query DNS for all possible address families. */
558 	*pai = ai0;
559 	error = explore_fqdn(pai, hostname, servname, &afai);
560 	if (error) {
561 		if (afai != NULL)
562 			freeaddrinfo(afai);
563 		goto free;
564 	}
565 	if (afai == NULL) {
566 		error = EAI_NONAME; /* we've had no errors. */
567 		goto free;
568 	}
569 
570 	/*
571 	 * we would like to prefer AF_INET6 than AF_INET, so we'll make an
572 	 * outer loop by AFs.
573 	 */
574 	for (ex = explore; ex->e_af >= 0; ex++) {
575 		*pai = ai0;
576 
577 		if (pai->ai_family == PF_UNSPEC)
578 			pai->ai_family = ex->e_af;
579 
580 		if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
581 			continue;
582 		if (!MATCH(pai->ai_socktype, ex->e_socktype,
583 			   WILD_SOCKTYPE(ex))) {
584 			continue;
585 		}
586 		if (!MATCH(pai->ai_protocol, ex->e_protocol,
587 			   WILD_PROTOCOL(ex))) {
588 			continue;
589 		}
590 
591 #ifdef AI_ADDRCONFIG
592 		/*
593 		 * If AI_ADDRCONFIG is specified, check if we are
594 		 * expected to return the address family or not.
595 		 */
596 		if ((pai->ai_flags & AI_ADDRCONFIG) != 0 &&
597 		    !addrconfig(pai->ai_family))
598 			continue;
599 #endif
600 
601 		if (pai->ai_family == PF_UNSPEC)
602 			pai->ai_family = ex->e_af;
603 		if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
604 			pai->ai_socktype = ex->e_socktype;
605 		if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
606 			pai->ai_protocol = ex->e_protocol;
607 
608 		/*
609 		 * if the servname does not match socktype/protocol, ignore it.
610 		 */
611 		if (get_portmatch(pai, servname) != 0)
612 			continue;
613 
614 		if ((error = explore_copy(pai, afai, &cur->ai_next)) != 0) {
615 			freeaddrinfo(afai);
616 			goto free;
617 		}
618 
619 		while (cur && cur->ai_next)
620 			cur = cur->ai_next;
621 	}
622 
623 	freeaddrinfo(afai);	/* afai must not be NULL at this point. */
624 
625 	/* we must not have got any errors. */
626 	if (error != 0) /* just for diagnosis */
627 		abort();
628 
629 	if (sentinel.ai_next) {
630 good:
631 		*res = sentinel.ai_next;
632 		return(SUCCESS);
633 	} else {
634 		/*
635 		 * All the process succeeded, but we've had an empty list.
636 		 * This can happen if the given hints do not match our
637 		 * candidates.
638 		 */
639 		error = EAI_NONAME;
640 	}
641 
642 free:
643 bad:
644 	if (sentinel.ai_next)
645 		freeaddrinfo(sentinel.ai_next);
646 	*res = NULL;
647 	return(error);
648 }
649 
650 /*
651  * FQDN hostname, DNS lookup
652  */
653 static int
654 explore_fqdn(pai, hostname, servname, res)
655 	const struct addrinfo *pai;
656 	const char *hostname;
657 	const char *servname;
658 	struct addrinfo **res;
659 {
660 	struct addrinfo *result;
661 	struct addrinfo *cur;
662 	struct net_data *net_data = init();
663 	struct irs_ho *ho;
664 	int error = 0;
665 	char tmp[NS_MAXDNAME];
666 	const char *cp;
667 
668 	INSIST(res != NULL && *res == NULL);
669 
670 	/*
671 	 * if the servname does not match socktype/protocol, ignore it.
672 	 */
673 	if (get_portmatch(pai, servname) != 0)
674 		return(0);
675 
676 	if (!net_data || !(ho = net_data->ho))
677 		return(0);
678 #if 0				/* XXX (notyet) */
679 	if (net_data->ho_stayopen && net_data->ho_last &&
680 	    net_data->ho_last->h_addrtype == af) {
681 		if (ns_samename(name, net_data->ho_last->h_name) == 1)
682 			return (net_data->ho_last);
683 		for (hap = net_data->ho_last->h_aliases; hap && *hap; hap++)
684 			if (ns_samename(name, *hap) == 1)
685 				return (net_data->ho_last);
686 	}
687 #endif
688 	if (!strchr(hostname, '.') &&
689 	    (cp = res_hostalias(net_data->res, hostname,
690 				tmp, sizeof(tmp))))
691 		hostname = cp;
692 	result = (*ho->addrinfo)(ho, hostname, pai);
693 	if (!net_data->ho_stayopen) {
694 		(*ho->minimize)(ho);
695 	}
696 	if (result == NULL) {
697 		int e = h_errno;
698 
699 		switch(e) {
700 		case NETDB_INTERNAL:
701 			error = EAI_SYSTEM;
702 			break;
703 		case TRY_AGAIN:
704 			error = EAI_AGAIN;
705 			break;
706 		case NO_RECOVERY:
707 			error = EAI_FAIL;
708 			break;
709 		case HOST_NOT_FOUND:
710 		case NO_DATA:
711 			error = EAI_NONAME;
712 			break;
713 		default:
714 		case NETDB_SUCCESS: /* should be impossible... */
715 			error = EAI_NONAME;
716 			break;
717 		}
718 		goto free;
719 	}
720 
721 	for (cur = result; cur; cur = cur->ai_next) {
722 		GET_PORT(cur, servname); /* XXX: redundant lookups... */
723 		/* canonname should already be filled. */
724 	}
725 
726 	*res = result;
727 
728 	return(0);
729 
730 free:
731 	if (result)
732 		freeaddrinfo(result);
733 	return error;
734 }
735 
736 static int
737 explore_copy(pai, src0, res)
738 	const struct addrinfo *pai;	/* seed */
739 	const struct addrinfo *src0;	/* source */
740 	struct addrinfo **res;
741 {
742 	int error;
743 	struct addrinfo sentinel, *cur;
744 	const struct addrinfo *src;
745 
746 	error = 0;
747 	sentinel.ai_next = NULL;
748 	cur = &sentinel;
749 
750 	for (src = src0; src != NULL; src = src->ai_next) {
751 		if (src->ai_family != pai->ai_family)
752 			continue;
753 
754 		cur->ai_next = copy_ai(src);
755 		if (!cur->ai_next) {
756 			error = EAI_MEMORY;
757 			goto fail;
758 		}
759 
760 		cur->ai_next->ai_socktype = pai->ai_socktype;
761 		cur->ai_next->ai_protocol = pai->ai_protocol;
762 		cur = cur->ai_next;
763 	}
764 
765 	*res = sentinel.ai_next;
766 	return 0;
767 
768 fail:
769 	freeaddrinfo(sentinel.ai_next);
770 	return error;
771 }
772 
773 /*
774  * hostname == NULL.
775  * passive socket -> anyaddr (0.0.0.0 or ::)
776  * non-passive socket -> localhost (127.0.0.1 or ::1)
777  */
778 static int
779 explore_null(pai, servname, res)
780 	const struct addrinfo *pai;
781 	const char *servname;
782 	struct addrinfo **res;
783 {
784 	const struct afd *afd;
785 	struct addrinfo *cur;
786 	struct addrinfo sentinel;
787 	int error;
788 
789 	*res = NULL;
790 	sentinel.ai_next = NULL;
791 	cur = &sentinel;
792 
793 	afd = find_afd(pai->ai_family);
794 	if (afd == NULL)
795 		return 0;
796 
797 	if (pai->ai_flags & AI_PASSIVE) {
798 		GET_AI(cur->ai_next, afd, afd->a_addrany);
799 		/* xxx meaningless?
800 		 * GET_CANONNAME(cur->ai_next, "anyaddr");
801 		 */
802 		GET_PORT(cur->ai_next, servname);
803 	} else {
804 		GET_AI(cur->ai_next, afd, afd->a_loopback);
805 		/* xxx meaningless?
806 		 * GET_CANONNAME(cur->ai_next, "localhost");
807 		 */
808 		GET_PORT(cur->ai_next, servname);
809 	}
810 	cur = cur->ai_next;
811 
812 	*res = sentinel.ai_next;
813 	return 0;
814 
815 free:
816 	if (sentinel.ai_next)
817 		freeaddrinfo(sentinel.ai_next);
818 	return error;
819 }
820 
821 /*
822  * numeric hostname
823  */
824 static int
825 explore_numeric(pai, hostname, servname, res)
826 	const struct addrinfo *pai;
827 	const char *hostname;
828 	const char *servname;
829 	struct addrinfo **res;
830 {
831 	const struct afd *afd;
832 	struct addrinfo *cur;
833 	struct addrinfo sentinel;
834 	int error;
835 	char pton[PTON_MAX];
836 
837 	*res = NULL;
838 	sentinel.ai_next = NULL;
839 	cur = &sentinel;
840 
841 	afd = find_afd(pai->ai_family);
842 	if (afd == NULL)
843 		return 0;
844 
845 	switch (afd->a_af) {
846 #if 0 /*X/Open spec*/
847 	case AF_INET:
848 		if (inet_aton(hostname, (struct in_addr *)pton) == 1) {
849 			if (pai->ai_family == afd->a_af ||
850 			    pai->ai_family == PF_UNSPEC /*?*/) {
851 				GET_AI(cur->ai_next, afd, pton);
852 				GET_PORT(cur->ai_next, servname);
853 				while (cur && cur->ai_next)
854 					cur = cur->ai_next;
855 			} else
856 				ERR(EAI_FAMILY);	/*xxx*/
857 		}
858 		break;
859 #endif
860 	default:
861 		if (inet_pton(afd->a_af, hostname, pton) == 1) {
862 			if (pai->ai_family == afd->a_af ||
863 			    pai->ai_family == PF_UNSPEC /*?*/) {
864 				GET_AI(cur->ai_next, afd, pton);
865 				GET_PORT(cur->ai_next, servname);
866 				while (cur && cur->ai_next)
867 					cur = cur->ai_next;
868 			} else {
869 				ERR(EAI_FAMILY);	/*xxx*/
870 #if !defined(ORIGINAL_ISC_CODE)
871 				goto bad;
872 #endif
873 			}
874 		}
875 		break;
876 	}
877 
878 	*res = sentinel.ai_next;
879 	return 0;
880 
881 free:
882 bad:
883 	if (sentinel.ai_next)
884 		freeaddrinfo(sentinel.ai_next);
885 	return error;
886 }
887 
888 /*
889  * numeric hostname with scope
890  */
891 static int
892 explore_numeric_scope(pai, hostname, servname, res)
893 	const struct addrinfo *pai;
894 	const char *hostname;
895 	const char *servname;
896 	struct addrinfo **res;
897 {
898 #ifndef SCOPE_DELIMITER
899 	return explore_numeric(pai, hostname, servname, res);
900 #else
901 	const struct afd *afd;
902 	struct addrinfo *cur;
903 	int error;
904 	char *cp, *hostname2 = NULL, *scope, *addr;
905 	struct sockaddr_in6 *sin6;
906 
907 	afd = find_afd(pai->ai_family);
908 	if (afd == NULL)
909 		return 0;
910 
911 	if (!afd->a_scoped)
912 		return explore_numeric(pai, hostname, servname, res);
913 
914 	cp = strchr(hostname, SCOPE_DELIMITER);
915 	if (cp == NULL)
916 		return explore_numeric(pai, hostname, servname, res);
917 
918 	/*
919 	 * Handle special case of <scoped_address><delimiter><scope id>
920 	 */
921 	hostname2 = strdup(hostname);
922 	if (hostname2 == NULL)
923 		return EAI_MEMORY;
924 	/* terminate at the delimiter */
925 	hostname2[cp - hostname] = '\0';
926 	addr = hostname2;
927 	scope = cp + 1;
928 
929 	error = explore_numeric(pai, addr, servname, res);
930 	if (error == 0) {
931 		u_int32_t scopeid = 0;
932 
933 		for (cur = *res; cur; cur = cur->ai_next) {
934 			if (cur->ai_family != AF_INET6)
935 				continue;
936 			sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
937 			if (!ip6_str2scopeid(scope, sin6, &scopeid)) {
938 				free(hostname2);
939 				return(EAI_NONAME); /* XXX: is return OK? */
940 			}
941 #ifdef HAVE_SIN6_SCOPE_ID
942 			sin6->sin6_scope_id = scopeid;
943 #endif
944 		}
945 	}
946 
947 	free(hostname2);
948 
949 	return error;
950 #endif
951 }
952 
953 static int
954 get_canonname(pai, ai, str)
955 	const struct addrinfo *pai;
956 	struct addrinfo *ai;
957 	const char *str;
958 {
959 	if ((pai->ai_flags & AI_CANONNAME) != 0) {
960 		ai->ai_canonname = (char *)malloc(strlen(str) + 1);
961 		if (ai->ai_canonname == NULL)
962 			return EAI_MEMORY;
963 		strcpy(ai->ai_canonname, str);
964 	}
965 	return 0;
966 }
967 
968 static struct addrinfo *
969 get_ai(pai, afd, addr)
970 	const struct addrinfo *pai;
971 	const struct afd *afd;
972 	const char *addr;
973 {
974 	char *p;
975 	struct addrinfo *ai;
976 
977 	ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
978 		+ (afd->a_socklen));
979 	if (ai == NULL)
980 		return NULL;
981 
982 	memcpy(ai, pai, sizeof(struct addrinfo));
983 	ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
984 	memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
985 #ifdef HAVE_SA_LEN
986 	ai->ai_addr->sa_len = afd->a_socklen;
987 #endif
988 	ai->ai_addrlen = afd->a_socklen;
989 	ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
990 	p = (char *)(void *)(ai->ai_addr);
991 	memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
992 	return ai;
993 }
994 
995 /* XXX need to malloc() the same way we do from other functions! */
996 static struct addrinfo *
997 copy_ai(pai)
998 	const struct addrinfo *pai;
999 {
1000 	struct addrinfo *ai;
1001 	size_t l;
1002 
1003 	l = sizeof(*ai) + pai->ai_addrlen;
1004 	if ((ai = (struct addrinfo *)malloc(l)) == NULL)
1005 		return NULL;
1006 	memset(ai, 0, l);
1007 	memcpy(ai, pai, sizeof(*ai));
1008 	ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
1009 	memcpy(ai->ai_addr, pai->ai_addr, pai->ai_addrlen);
1010 
1011 	if (pai->ai_canonname) {
1012 		l = strlen(pai->ai_canonname) + 1;
1013 		if ((ai->ai_canonname = malloc(l)) == NULL) {
1014 			free(ai);
1015 			return NULL;
1016 		}
1017 #ifdef HAVE_STRLCPY
1018 		strlcpy(ai->ai_canonname, pai->ai_canonname, l);
1019 #else
1020 		strncpy(ai->ai_canonname, pai->ai_canonname, l);
1021 #endif
1022 	} else {
1023 		/* just to make sure */
1024 		ai->ai_canonname = NULL;
1025 	}
1026 
1027 	ai->ai_next = NULL;
1028 
1029 	return ai;
1030 }
1031 
1032 static int
1033 get_portmatch(const struct addrinfo *ai, const char *servname) {
1034 
1035 	/* get_port does not touch first argument. when matchonly == 1. */
1036 	/* LINTED const cast */
1037 	return get_port((const struct addrinfo *)ai, servname, 1);
1038 }
1039 
1040 static int
1041 get_port(const struct addrinfo *ai, const char *servname, int matchonly) {
1042 	const char *proto;
1043 	struct servent *sp;
1044 	int port;
1045 	int allownumeric;
1046 
1047 	if (servname == NULL)
1048 		return 0;
1049 	switch (ai->ai_family) {
1050 	case AF_INET:
1051 #ifdef AF_INET6
1052 	case AF_INET6:
1053 #endif
1054 		break;
1055 	default:
1056 		return 0;
1057 	}
1058 
1059 	switch (ai->ai_socktype) {
1060 	case SOCK_RAW:
1061 		return EAI_SERVICE;
1062 	case SOCK_DGRAM:
1063 	case SOCK_STREAM:
1064 		allownumeric = 1;
1065 		break;
1066 	case ANY:
1067 		switch (ai->ai_family) {
1068 		case AF_INET:
1069 #ifdef AF_INET6
1070 		case AF_INET6:
1071 #endif
1072 			allownumeric = 1;
1073 			break;
1074 		default:
1075 			allownumeric = 0;
1076 			break;
1077 		}
1078 		break;
1079 	default:
1080 		return EAI_SOCKTYPE;
1081 	}
1082 
1083 	if (str_isnumber(servname)) {
1084 		if (!allownumeric)
1085 			return EAI_SERVICE;
1086 		port = atoi(servname);
1087 		if (port < 0 || port > 65535)
1088 			return EAI_SERVICE;
1089 		port = htons(port);
1090 	} else {
1091 		switch (ai->ai_socktype) {
1092 		case SOCK_DGRAM:
1093 			proto = "udp";
1094 			break;
1095 		case SOCK_STREAM:
1096 			proto = "tcp";
1097 			break;
1098 		default:
1099 			proto = NULL;
1100 			break;
1101 		}
1102 
1103 		if ((sp = getservbyname(servname, proto)) == NULL)
1104 			return EAI_SERVICE;
1105 		port = sp->s_port;
1106 	}
1107 
1108 	if (!matchonly) {
1109 		switch (ai->ai_family) {
1110 		case AF_INET:
1111 			((struct sockaddr_in *)(void *)
1112 			    ai->ai_addr)->sin_port = port;
1113 			break;
1114 		case AF_INET6:
1115 			((struct sockaddr_in6 *)(void *)
1116 			    ai->ai_addr)->sin6_port = port;
1117 			break;
1118 		}
1119 	}
1120 
1121 	return 0;
1122 }
1123 
1124 static const struct afd *
1125 find_afd(af)
1126 	int af;
1127 {
1128 	const struct afd *afd;
1129 
1130 	if (af == PF_UNSPEC)
1131 		return NULL;
1132 	for (afd = afdl; afd->a_af; afd++) {
1133 		if (afd->a_af == af)
1134 			return afd;
1135 	}
1136 	return NULL;
1137 }
1138 
1139 /*
1140  * post-2553: AI_ADDRCONFIG check.  if we use getipnodeby* as backend, backend
1141  * will take care of it.
1142  * the semantics of AI_ADDRCONFIG is not defined well.  we are not sure
1143  * if the code is right or not.
1144  */
1145 static int
1146 addrconfig(af)
1147 	int af;
1148 {
1149 	int s;
1150 
1151 	/* XXX errno */
1152 	s = socket(af, SOCK_DGRAM, 0);
1153 	if (s < 0) {
1154 		if (errno != EMFILE)
1155 			return 0;
1156 	} else
1157 		close(s);
1158 	return 1;
1159 }
1160 
1161 /* convert a string to a scope identifier. XXX: IPv6 specific */
1162 static int
1163 ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6,
1164 		u_int32_t *scopeidp)
1165 {
1166 	u_int32_t scopeid;
1167 	u_long lscopeid;
1168 	struct in6_addr *a6 = &sin6->sin6_addr;
1169 	char *ep;
1170 
1171 	/* empty scopeid portion is invalid */
1172 	if (*scope == '\0')
1173 		return (0);
1174 
1175 #ifdef USE_IFNAMELINKID
1176 	if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) {
1177 		/*
1178 		 * Using interface names as link indices can be allowed
1179 		 * only when we can assume a one-to-one mappings between
1180 		 * links and interfaces.  See comments in getnameinfo.c.
1181 		 */
1182 		scopeid = if_nametoindex(scope);
1183 		if (scopeid == 0)
1184 			goto trynumeric;
1185 		*scopeidp = scopeid;
1186 		return (1);
1187 	}
1188 #endif
1189 
1190 	/* still unclear about literal, allow numeric only - placeholder */
1191 	if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
1192 		goto trynumeric;
1193 	if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
1194 		goto trynumeric;
1195 	else
1196 		goto trynumeric;	/* global */
1197 
1198 	/* try to convert to a numeric id as a last resort */
1199 trynumeric:
1200 	errno = 0;
1201 	lscopeid = strtoul(scope, &ep, 10);
1202 	scopeid = lscopeid & 0xffffffff;
1203 	if (errno == 0 && ep && *ep == '\0' && scopeid == lscopeid) {
1204 		*scopeidp = scopeid;
1205 		return (1);
1206 	} else
1207 		return (0);
1208 }
1209 
1210 struct addrinfo *
1211 hostent2addrinfo(hp, pai)
1212 	struct hostent *hp;
1213 	const struct addrinfo *pai;
1214 {
1215 	int i, af, error = 0;
1216 	char **aplist = NULL, *ap;
1217 	struct addrinfo sentinel, *cur;
1218 	const struct afd *afd;
1219 
1220 	af = hp->h_addrtype;
1221 	if (pai->ai_family != AF_UNSPEC && af != pai->ai_family)
1222 		return(NULL);
1223 
1224 	afd = find_afd(af);
1225 	if (afd == NULL)
1226 		return(NULL);
1227 
1228 	aplist = hp->h_addr_list;
1229 
1230 	memset(&sentinel, 0, sizeof(sentinel));
1231 	cur = &sentinel;
1232 
1233 	for (i = 0; (ap = aplist[i]) != NULL; i++) {
1234 #if 0				/* the trick seems too much */
1235 		af = hp->h_addr_list;
1236 		if (af == AF_INET6 &&
1237 		    IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ap)) {
1238 			af = AF_INET;
1239 			ap = ap + sizeof(struct in6_addr)
1240 				- sizeof(struct in_addr);
1241 		}
1242 		afd = find_afd(af);
1243 		if (afd == NULL)
1244 			continue;
1245 #endif /* 0 */
1246 
1247 		GET_AI(cur->ai_next, afd, ap);
1248 
1249 		/* GET_PORT(cur->ai_next, servname); */
1250 		if ((pai->ai_flags & AI_CANONNAME) != 0) {
1251 			/*
1252 			 * RFC2553 says that ai_canonname will be set only for
1253 			 * the first element.  we do it for all the elements,
1254 			 * just for convenience.
1255 			 */
1256 			GET_CANONNAME(cur->ai_next, hp->h_name);
1257 		}
1258 		while (cur && cur->ai_next) /* no need to loop, actually. */
1259 			cur = cur->ai_next;
1260 		continue;
1261 
1262 	free:
1263 		if (cur->ai_next)
1264 			freeaddrinfo(cur->ai_next);
1265 		cur->ai_next = NULL;
1266 		/* continue, without tht pointer CUR advanced. */
1267 	}
1268 
1269 	return(sentinel.ai_next);
1270 }
1271 
1272 struct addrinfo *
1273 addr2addrinfo(pai, cp)
1274 	const struct addrinfo *pai;
1275 	const char *cp;
1276 {
1277 	const struct afd *afd;
1278 
1279 	afd = find_afd(pai->ai_family);
1280 	if (afd == NULL)
1281 		return(NULL);
1282 
1283 	return(get_ai(pai, afd, cp));
1284 }
1285 
1286 static struct net_data *
1287 init()
1288 {
1289 	struct net_data *net_data;
1290 
1291 	if (!(net_data = net_data_init(NULL)))
1292 		goto error;
1293 	if (!net_data->ho) {
1294 		net_data->ho = (*net_data->irs->ho_map)(net_data->irs);
1295 		if (!net_data->ho || !net_data->res) {
1296 error:
1297 			errno = EIO;
1298 			if (net_data && net_data->res)
1299 				RES_SET_H_ERRNO(net_data->res, NETDB_INTERNAL);
1300 			return (NULL);
1301 		}
1302 
1303 		(*net_data->ho->res_set)(net_data->ho, net_data->res, NULL);
1304 	}
1305 
1306 	return (net_data);
1307 }
1308