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      1 /*
      2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. Neither the name of the project nor the names of its contributors
     14  *    may be used to endorse or promote products derived from this software
     15  *    without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     27  * SUCH DAMAGE.
     28  */
     29 
     30 /*
     31  * "#ifdef FAITH" part is local hack for supporting IPv4-v6 translator.
     32  *
     33  * Issues to be discussed:
     34  * - Thread safe-ness must be checked.
     35  * - Return values.  There are nonstandard return values defined and used
     36  *   in the source code.  This is because RFC2553 is silent about which error
     37  *   code must be returned for which situation.
     38  * Note:
     39  * - We use getipnodebyname() just for thread-safeness.  There's no intent
     40  *   to let it do PF_UNSPEC (actually we never pass PF_UNSPEC to
     41  *   getipnodebyname().
     42  * - The code filters out AFs that are not supported by the kernel,
     43  *   when globbing NULL hostname (to loopback, or wildcard).  Is it the right
     44  *   thing to do?  What is the relationship with post-RFC2553 AI_ADDRCONFIG
     45  *   in ai_flags?
     46  */
     47 
     48 #ifdef HAVE_CONFIG_H
     49 #include <config.h>
     50 #endif
     51 
     52 #ifndef lint
     53 static const char rcsid[] _U_ =
     54      "@(#) $Header: /tcpdump/master/tcpdump/missing/getaddrinfo.c,v 1.13 2003/11/16 09:36:48 guy Exp $";
     55 #endif
     56 
     57 #include <sys/types.h>
     58 #include <sys/param.h>
     59 #if 0
     60 #include <sys/sysctl.h>
     61 #endif
     62 #include <sys/socket.h>
     63 #include <net/if.h>
     64 #include <netinet/in.h>
     65 #include <arpa/inet.h>
     66 #include <arpa/nameser.h>
     67 #include <netdb.h>
     68 #include <resolv.h>
     69 #include <string.h>
     70 #include <stdlib.h>
     71 #include <stddef.h>
     72 #include <ctype.h>
     73 #include <unistd.h>
     74 #include <stdio.h>
     75 #include <errno.h>
     76 
     77 #ifndef HAVE_U_INT32_T
     78 #include "bittypes.h"
     79 #endif
     80 
     81 #ifndef HAVE_SOCKADDR_STORAGE
     82 #include "sockstorage.h"
     83 #endif
     84 
     85 #ifdef NEED_ADDRINFO_H
     86 #include "addrinfo.h"
     87 #endif
     88 
     89 #if defined(__KAME__) && defined(INET6)
     90 # define FAITH
     91 #endif
     92 
     93 #define SUCCESS 0
     94 #define ANY 0
     95 #define YES 1
     96 #define NO  0
     97 
     98 #ifdef FAITH
     99 static int translate = NO;
    100 static struct in6_addr faith_prefix = IN6ADDR_ANY_INIT;
    101 #endif
    102 
    103 static const char in_addrany[] = { 0, 0, 0, 0 };
    104 static const char in6_addrany[] = {
    105 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
    106 };
    107 static const char in_loopback[] = { 127, 0, 0, 1 };
    108 static const char in6_loopback[] = {
    109 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
    110 };
    111 
    112 struct sockinet {
    113 	u_char	si_len;
    114 	u_char	si_family;
    115 	u_short	si_port;
    116 	u_int32_t si_scope_id;
    117 };
    118 
    119 static const struct afd {
    120 	int a_af;
    121 	int a_addrlen;
    122 	int a_socklen;
    123 	int a_off;
    124 	const char *a_addrany;
    125 	const char *a_loopback;
    126 	int a_scoped;
    127 } afdl [] = {
    128 #ifdef INET6
    129 	{PF_INET6, sizeof(struct in6_addr),
    130 	 sizeof(struct sockaddr_in6),
    131 	 offsetof(struct sockaddr_in6, sin6_addr),
    132 	 in6_addrany, in6_loopback, 1},
    133 #endif
    134 	{PF_INET, sizeof(struct in_addr),
    135 	 sizeof(struct sockaddr_in),
    136 	 offsetof(struct sockaddr_in, sin_addr),
    137 	 in_addrany, in_loopback, 0},
    138 	{0, 0, 0, 0, NULL, NULL, 0},
    139 };
    140 
    141 struct explore {
    142 	int e_af;
    143 	int e_socktype;
    144 	int e_protocol;
    145 	const char *e_protostr;
    146 	int e_wild;
    147 #define WILD_AF(ex)		((ex)->e_wild & 0x01)
    148 #define WILD_SOCKTYPE(ex)	((ex)->e_wild & 0x02)
    149 #define WILD_PROTOCOL(ex)	((ex)->e_wild & 0x04)
    150 };
    151 
    152 static const struct explore explore[] = {
    153 #if 0
    154 	{ PF_LOCAL, 0, ANY, ANY, NULL, 0x01 },
    155 #endif
    156 #ifdef INET6
    157 	{ PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
    158 	{ PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
    159 	{ PF_INET6, SOCK_RAW, ANY, NULL, 0x05 },
    160 #endif
    161 	{ PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
    162 	{ PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
    163 	{ PF_INET, SOCK_RAW, ANY, NULL, 0x05 },
    164 	{ -1, 0, 0, NULL, 0 },
    165 };
    166 
    167 #ifdef INET6
    168 #define PTON_MAX	16
    169 #else
    170 #define PTON_MAX	4
    171 #endif
    172 
    173 
    174 static int str_isnumber (const char *);
    175 static int explore_fqdn (const struct addrinfo *, const char *,
    176 	const char *, struct addrinfo **);
    177 static int explore_null (const struct addrinfo *, const char *,
    178 	const char *, struct addrinfo **);
    179 static int explore_numeric (const struct addrinfo *, const char *,
    180 	const char *, struct addrinfo **);
    181 static int explore_numeric_scope (const struct addrinfo *, const char *,
    182 	const char *, struct addrinfo **);
    183 static int get_name (const char *, const struct afd *, struct addrinfo **,
    184 	char *, const struct addrinfo *, const char *);
    185 static int get_canonname (const struct addrinfo *,
    186 	struct addrinfo *, const char *);
    187 static struct addrinfo *get_ai (const struct addrinfo *,
    188 	const struct afd *, const char *);
    189 static int get_portmatch (const struct addrinfo *, const char *);
    190 static int get_port (struct addrinfo *, const char *, int);
    191 static const struct afd *find_afd (int);
    192 
    193 static char *ai_errlist[] = {
    194 	"Success",
    195 	"Address family for hostname not supported",	/* EAI_ADDRFAMILY */
    196 	"Temporary failure in name resolution",		/* EAI_AGAIN      */
    197 	"Invalid value for ai_flags",		       	/* EAI_BADFLAGS   */
    198 	"Non-recoverable failure in name resolution", 	/* EAI_FAIL       */
    199 	"ai_family not supported",			/* EAI_FAMILY     */
    200 	"Memory allocation failure", 			/* EAI_MEMORY     */
    201 	"No address associated with hostname", 		/* EAI_NODATA     */
    202 	"hostname nor servname provided, or not known",	/* EAI_NONAME     */
    203 	"servname not supported for ai_socktype",	/* EAI_SERVICE    */
    204 	"ai_socktype not supported", 			/* EAI_SOCKTYPE   */
    205 	"System error returned in errno", 		/* EAI_SYSTEM     */
    206 	"Invalid value for hints",			/* EAI_BADHINTS	  */
    207 	"Resolved protocol is unknown",			/* EAI_PROTOCOL   */
    208 	"Unknown error", 				/* EAI_MAX        */
    209 };
    210 
    211 /* XXX macros that make external reference is BAD. */
    212 
    213 #define GET_AI(ai, afd, addr) \
    214 do { \
    215 	/* external reference: pai, error, and label free */ \
    216 	(ai) = get_ai(pai, (afd), (addr)); \
    217 	if ((ai) == NULL) { \
    218 		error = EAI_MEMORY; \
    219 		goto free; \
    220 	} \
    221 } while (0)
    222 
    223 #define GET_PORT(ai, serv) \
    224 do { \
    225 	/* external reference: error and label free */ \
    226 	error = get_port((ai), (serv), 0); \
    227 	if (error != 0) \
    228 		goto free; \
    229 } while (0)
    230 
    231 #define GET_CANONNAME(ai, str) \
    232 do { \
    233 	/* external reference: pai, error and label free */ \
    234 	error = get_canonname(pai, (ai), (str)); \
    235 	if (error != 0) \
    236 		goto free; \
    237 } while (0)
    238 
    239 #define ERR(err) \
    240 do { \
    241 	/* external reference: error, and label bad */ \
    242 	error = (err); \
    243 	goto bad; \
    244 } while (0)
    245 
    246 #define MATCH_FAMILY(x, y, w) \
    247 	((x) == (y) || ((w) && ((x) == PF_UNSPEC || (y) == PF_UNSPEC)))
    248 #define MATCH(x, y, w) \
    249 	((x) == (y) || ((w) && ((x) == ANY || (y) == ANY)))
    250 
    251 char *
    252 gai_strerror(ecode)
    253 	int ecode;
    254 {
    255 	if (ecode < 0 || ecode > EAI_MAX)
    256 		ecode = EAI_MAX;
    257 	return ai_errlist[ecode];
    258 }
    259 
    260 void
    261 freeaddrinfo(ai)
    262 	struct addrinfo *ai;
    263 {
    264 	struct addrinfo *next;
    265 
    266 	do {
    267 		next = ai->ai_next;
    268 		if (ai->ai_canonname)
    269 			free(ai->ai_canonname);
    270 		/* no need to free(ai->ai_addr) */
    271 		free(ai);
    272 	} while ((ai = next) != NULL);
    273 }
    274 
    275 static int
    276 str_isnumber(p)
    277 	const char *p;
    278 {
    279 	char *q = (char *)p;
    280 	while (*q) {
    281 		if (! isdigit(*q))
    282 			return NO;
    283 		q++;
    284 	}
    285 	return YES;
    286 }
    287 
    288 int
    289 getaddrinfo(hostname, servname, hints, res)
    290 	const char *hostname, *servname;
    291 	const struct addrinfo *hints;
    292 	struct addrinfo **res;
    293 {
    294 	struct addrinfo sentinel;
    295 	struct addrinfo *cur;
    296 	int error = 0;
    297 	struct addrinfo ai;
    298 	struct addrinfo ai0;
    299 	struct addrinfo *pai;
    300 	const struct afd *afd;
    301 	const struct explore *ex;
    302 
    303 #ifdef FAITH
    304 	static int firsttime = 1;
    305 
    306 	if (firsttime) {
    307 		/* translator hack */
    308 		char *q = getenv("GAI");
    309 		if (q && inet_pton(AF_INET6, q, &faith_prefix) == 1)
    310 			translate = YES;
    311 		firsttime = 0;
    312 	}
    313 #endif
    314 
    315 	sentinel.ai_next = NULL;
    316 	cur = &sentinel;
    317 	pai = &ai;
    318 	pai->ai_flags = 0;
    319 	pai->ai_family = PF_UNSPEC;
    320 	pai->ai_socktype = ANY;
    321 	pai->ai_protocol = ANY;
    322 	pai->ai_addrlen = 0;
    323 	pai->ai_canonname = NULL;
    324 	pai->ai_addr = NULL;
    325 	pai->ai_next = NULL;
    326 
    327 	if (hostname == NULL && servname == NULL)
    328 		return EAI_NONAME;
    329 	if (hints) {
    330 		/* error check for hints */
    331 		if (hints->ai_addrlen || hints->ai_canonname ||
    332 		    hints->ai_addr || hints->ai_next)
    333 			ERR(EAI_BADHINTS); /* xxx */
    334 		if (hints->ai_flags & ~AI_MASK)
    335 			ERR(EAI_BADFLAGS);
    336 		switch (hints->ai_family) {
    337 		case PF_UNSPEC:
    338 		case PF_INET:
    339 #ifdef INET6
    340 		case PF_INET6:
    341 #endif
    342 			break;
    343 		default:
    344 			ERR(EAI_FAMILY);
    345 		}
    346 		memcpy(pai, hints, sizeof(*pai));
    347 
    348 		/*
    349 		 * if both socktype/protocol are specified, check if they
    350 		 * are meaningful combination.
    351 		 */
    352 		if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
    353 			for (ex = explore; ex->e_af >= 0; ex++) {
    354 				if (pai->ai_family != ex->e_af)
    355 					continue;
    356 				if (ex->e_socktype == ANY)
    357 					continue;
    358 				if (ex->e_protocol == ANY)
    359 					continue;
    360 				if (pai->ai_socktype == ex->e_socktype
    361 				 && pai->ai_protocol != ex->e_protocol) {
    362 					ERR(EAI_BADHINTS);
    363 				}
    364 			}
    365 		}
    366 	}
    367 
    368 	/*
    369 	 * check for special cases.  (1) numeric servname is disallowed if
    370 	 * socktype/protocol are left unspecified. (2) servname is disallowed
    371 	 * for raw and other inet{,6} sockets.
    372 	 */
    373 	if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
    374 #ifdef PF_INET6
    375 	 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
    376 #endif
    377 	    ) {
    378 		ai0 = *pai;
    379 
    380 		if (pai->ai_family == PF_UNSPEC) {
    381 #ifdef PF_INET6
    382 			pai->ai_family = PF_INET6;
    383 #else
    384 			pai->ai_family = PF_INET;
    385 #endif
    386 		}
    387 		error = get_portmatch(pai, servname);
    388 		if (error)
    389 			ERR(error);
    390 
    391 		*pai = ai0;
    392 	}
    393 
    394 	ai0 = *pai;
    395 
    396 	/* NULL hostname, or numeric hostname */
    397 	for (ex = explore; ex->e_af >= 0; ex++) {
    398 		*pai = ai0;
    399 
    400 		if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
    401 			continue;
    402 		if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex)))
    403 			continue;
    404 		if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex)))
    405 			continue;
    406 
    407 		if (pai->ai_family == PF_UNSPEC)
    408 			pai->ai_family = ex->e_af;
    409 		if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
    410 			pai->ai_socktype = ex->e_socktype;
    411 		if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
    412 			pai->ai_protocol = ex->e_protocol;
    413 
    414 		if (hostname == NULL)
    415 			error = explore_null(pai, hostname, servname, &cur->ai_next);
    416 		else
    417 			error = explore_numeric_scope(pai, hostname, servname, &cur->ai_next);
    418 
    419 		if (error)
    420 			goto free;
    421 
    422 		while (cur && cur->ai_next)
    423 			cur = cur->ai_next;
    424 	}
    425 
    426 	/*
    427 	 * XXX
    428 	 * If numreic representation of AF1 can be interpreted as FQDN
    429 	 * representation of AF2, we need to think again about the code below.
    430 	 */
    431 	if (sentinel.ai_next)
    432 		goto good;
    433 
    434 	if (pai->ai_flags & AI_NUMERICHOST)
    435 		ERR(EAI_NONAME);
    436 	if (hostname == NULL)
    437 		ERR(EAI_NONAME);
    438 
    439 	/*
    440 	 * hostname as alphabetical name.
    441 	 * we would like to prefer AF_INET6 than AF_INET, so we'll make a
    442 	 * outer loop by AFs.
    443 	 */
    444 	for (afd = afdl; afd->a_af; afd++) {
    445 		*pai = ai0;
    446 
    447 		if (!MATCH_FAMILY(pai->ai_family, afd->a_af, 1))
    448 			continue;
    449 
    450 		for (ex = explore; ex->e_af >= 0; ex++) {
    451 			*pai = ai0;
    452 
    453 			if (pai->ai_family == PF_UNSPEC)
    454 				pai->ai_family = afd->a_af;
    455 
    456 			if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
    457 				continue;
    458 			if (!MATCH(pai->ai_socktype, ex->e_socktype,
    459 					WILD_SOCKTYPE(ex))) {
    460 				continue;
    461 			}
    462 			if (!MATCH(pai->ai_protocol, ex->e_protocol,
    463 					WILD_PROTOCOL(ex))) {
    464 				continue;
    465 			}
    466 
    467 			if (pai->ai_family == PF_UNSPEC)
    468 				pai->ai_family = ex->e_af;
    469 			if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
    470 				pai->ai_socktype = ex->e_socktype;
    471 			if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
    472 				pai->ai_protocol = ex->e_protocol;
    473 
    474 			error = explore_fqdn(pai, hostname, servname,
    475 				&cur->ai_next);
    476 
    477 			while (cur && cur->ai_next)
    478 				cur = cur->ai_next;
    479 		}
    480 	}
    481 
    482 	/* XXX */
    483 	if (sentinel.ai_next)
    484 		error = 0;
    485 
    486 	if (error)
    487 		goto free;
    488 	if (error == 0) {
    489 		if (sentinel.ai_next) {
    490  good:
    491 			*res = sentinel.ai_next;
    492 			return SUCCESS;
    493 		} else
    494 			error = EAI_FAIL;
    495 	}
    496  free:
    497  bad:
    498 	if (sentinel.ai_next)
    499 		freeaddrinfo(sentinel.ai_next);
    500 	*res = NULL;
    501 	return error;
    502 }
    503 
    504 /*
    505  * FQDN hostname, DNS lookup
    506  */
    507 static int
    508 explore_fqdn(pai, hostname, servname, res)
    509 	const struct addrinfo *pai;
    510 	const char *hostname;
    511 	const char *servname;
    512 	struct addrinfo **res;
    513 {
    514 	struct hostent *hp;
    515 	int h_error;
    516 	int af;
    517 	char **aplist = NULL, *apbuf = NULL;
    518 	char *ap;
    519 	struct addrinfo sentinel, *cur;
    520 	int i;
    521 #ifndef USE_GETIPNODEBY
    522 	int naddrs;
    523 #endif
    524 	const struct afd *afd;
    525 	int error;
    526 
    527 	*res = NULL;
    528 	sentinel.ai_next = NULL;
    529 	cur = &sentinel;
    530 
    531 	/*
    532 	 * Do not filter unsupported AFs here.  We need to honor content of
    533 	 * databases (/etc/hosts, DNS and others).  Otherwise we cannot
    534 	 * replace gethostbyname() by getaddrinfo().
    535 	 */
    536 
    537 	/*
    538 	 * if the servname does not match socktype/protocol, ignore it.
    539 	 */
    540 	if (get_portmatch(pai, servname) != 0)
    541 		return 0;
    542 
    543 	afd = find_afd(pai->ai_family);
    544 
    545 	/*
    546 	 * post-RFC2553: should look at (pai->ai_flags & AI_ADDRCONFIG)
    547 	 * rather than hardcoding it.  we may need to add AI_ADDRCONFIG
    548 	 * handling code by ourselves in case we don't have getipnodebyname().
    549 	 */
    550 #ifdef USE_GETIPNODEBY
    551 	hp = getipnodebyname(hostname, pai->ai_family, AI_ADDRCONFIG, &h_error);
    552 #else
    553 #ifdef HAVE_GETHOSTBYNAME2
    554 	hp = gethostbyname2(hostname, pai->ai_family);
    555 #else
    556 	if (pai->ai_family != AF_INET)
    557 		return 0;
    558 	hp = gethostbyname(hostname);
    559 #ifdef HAVE_H_ERRNO
    560 	h_error = h_errno;
    561 #else
    562 	h_error = EINVAL;
    563 #endif
    564 #endif /*HAVE_GETHOSTBYNAME2*/
    565 #endif /*USE_GETIPNODEBY*/
    566 
    567 	if (hp == NULL) {
    568 		switch (h_error) {
    569 		case HOST_NOT_FOUND:
    570 		case NO_DATA:
    571 			error = EAI_NODATA;
    572 			break;
    573 		case TRY_AGAIN:
    574 			error = EAI_AGAIN;
    575 			break;
    576 		case NO_RECOVERY:
    577 		case NETDB_INTERNAL:
    578 		default:
    579 			error = EAI_FAIL;
    580 			break;
    581 		}
    582 	} else if ((hp->h_name == NULL) || (hp->h_name[0] == 0)
    583 			|| (hp->h_addr_list[0] == NULL)) {
    584 #ifdef USE_GETIPNODEBY
    585 		freehostent(hp);
    586 #endif
    587 		hp = NULL;
    588 		error = EAI_FAIL;
    589 	}
    590 
    591 	if (hp == NULL)
    592 		goto free;
    593 
    594 #ifdef USE_GETIPNODEBY
    595 	aplist = hp->h_addr_list;
    596 #else
    597 	/*
    598 	 * hp will be overwritten if we use gethostbyname2().
    599 	 * always deep copy for simplification.
    600 	 */
    601 	for (naddrs = 0; hp->h_addr_list[naddrs] != NULL; naddrs++)
    602 		;
    603 	naddrs++;
    604 	aplist = (char **)malloc(sizeof(aplist[0]) * naddrs);
    605 	apbuf = (char *)malloc(hp->h_length * naddrs);
    606 	if (aplist == NULL || apbuf == NULL) {
    607 		error = EAI_MEMORY;
    608 		goto free;
    609 	}
    610 	memset(aplist, 0, sizeof(aplist[0]) * naddrs);
    611 	for (i = 0; i < naddrs; i++) {
    612 		if (hp->h_addr_list[i] == NULL) {
    613 			aplist[i] = NULL;
    614 			continue;
    615 		}
    616 		memcpy(&apbuf[i * hp->h_length], hp->h_addr_list[i],
    617 			hp->h_length);
    618 		aplist[i] = &apbuf[i * hp->h_length];
    619 	}
    620 #endif
    621 
    622 	for (i = 0; aplist[i] != NULL; i++) {
    623 		af = hp->h_addrtype;
    624 		ap = aplist[i];
    625 #ifdef AF_INET6
    626 		if (af == AF_INET6
    627 		 && IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ap)) {
    628 			af = AF_INET;
    629 			ap = ap + sizeof(struct in6_addr)
    630 				- sizeof(struct in_addr);
    631 		}
    632 #endif
    633 
    634 		if (af != pai->ai_family)
    635 			continue;
    636 
    637 		if ((pai->ai_flags & AI_CANONNAME) == 0) {
    638 			GET_AI(cur->ai_next, afd, ap);
    639 			GET_PORT(cur->ai_next, servname);
    640 		} else {
    641 			/*
    642 			 * if AI_CANONNAME and if reverse lookup
    643 			 * fail, return ai anyway to pacify
    644 			 * calling application.
    645 			 *
    646 			 * XXX getaddrinfo() is a name->address
    647 			 * translation function, and it looks
    648 			 * strange that we do addr->name
    649 			 * translation here.
    650 			 */
    651 			get_name(ap, afd, &cur->ai_next,
    652 				ap, pai, servname);
    653 		}
    654 
    655 		while (cur && cur->ai_next)
    656 			cur = cur->ai_next;
    657 	}
    658 
    659 	*res = sentinel.ai_next;
    660 	return 0;
    661 
    662 free:
    663 #ifdef USE_GETIPNODEBY
    664 	if (hp)
    665 		freehostent(hp);
    666 #endif
    667 	if (aplist)
    668 		free(aplist);
    669 	if (apbuf)
    670 		free(apbuf);
    671 	if (sentinel.ai_next)
    672 		freeaddrinfo(sentinel.ai_next);
    673 	return error;
    674 }
    675 
    676 /*
    677  * hostname == NULL.
    678  * passive socket -> anyaddr (0.0.0.0 or ::)
    679  * non-passive socket -> localhost (127.0.0.1 or ::1)
    680  */
    681 static int
    682 explore_null(pai, hostname, servname, res)
    683 	const struct addrinfo *pai;
    684 	const char *hostname;
    685 	const char *servname;
    686 	struct addrinfo **res;
    687 {
    688 	int s;
    689 	const struct afd *afd;
    690 	struct addrinfo *cur;
    691 	struct addrinfo sentinel;
    692 	int error;
    693 
    694 	*res = NULL;
    695 	sentinel.ai_next = NULL;
    696 	cur = &sentinel;
    697 
    698 	/*
    699 	 * filter out AFs that are not supported by the kernel
    700 	 * XXX errno?
    701 	 */
    702 	s = socket(pai->ai_family, SOCK_DGRAM, 0);
    703 	if (s < 0) {
    704 		if (errno != EMFILE)
    705 			return 0;
    706 	} else
    707 		close(s);
    708 
    709 	/*
    710 	 * if the servname does not match socktype/protocol, ignore it.
    711 	 */
    712 	if (get_portmatch(pai, servname) != 0)
    713 		return 0;
    714 
    715 	afd = find_afd(pai->ai_family);
    716 
    717 	if (pai->ai_flags & AI_PASSIVE) {
    718 		GET_AI(cur->ai_next, afd, afd->a_addrany);
    719 		/* xxx meaningless?
    720 		 * GET_CANONNAME(cur->ai_next, "anyaddr");
    721 		 */
    722 		GET_PORT(cur->ai_next, servname);
    723 	} else {
    724 		GET_AI(cur->ai_next, afd, afd->a_loopback);
    725 		/* xxx meaningless?
    726 		 * GET_CANONNAME(cur->ai_next, "localhost");
    727 		 */
    728 		GET_PORT(cur->ai_next, servname);
    729 	}
    730 	cur = cur->ai_next;
    731 
    732 	*res = sentinel.ai_next;
    733 	return 0;
    734 
    735 free:
    736 	if (sentinel.ai_next)
    737 		freeaddrinfo(sentinel.ai_next);
    738 	return error;
    739 }
    740 
    741 /*
    742  * numeric hostname
    743  */
    744 static int
    745 explore_numeric(pai, hostname, servname, res)
    746 	const struct addrinfo *pai;
    747 	const char *hostname;
    748 	const char *servname;
    749 	struct addrinfo **res;
    750 {
    751 	const struct afd *afd;
    752 	struct addrinfo *cur;
    753 	struct addrinfo sentinel;
    754 	int error;
    755 	char pton[PTON_MAX];
    756 	int flags;
    757 
    758 	*res = NULL;
    759 	sentinel.ai_next = NULL;
    760 	cur = &sentinel;
    761 
    762 	/*
    763 	 * if the servname does not match socktype/protocol, ignore it.
    764 	 */
    765 	if (get_portmatch(pai, servname) != 0)
    766 		return 0;
    767 
    768 	afd = find_afd(pai->ai_family);
    769 	flags = pai->ai_flags;
    770 
    771 	if (inet_pton(afd->a_af, hostname, pton) == 1) {
    772 		u_int32_t v4a;
    773 #ifdef INET6
    774 		u_char pfx;
    775 #endif
    776 
    777 		switch (afd->a_af) {
    778 		case AF_INET:
    779 			v4a = (u_int32_t)ntohl(((struct in_addr *)pton)->s_addr);
    780 			if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
    781 				flags &= ~AI_CANONNAME;
    782 			v4a >>= IN_CLASSA_NSHIFT;
    783 			if (v4a == 0 || v4a == IN_LOOPBACKNET)
    784 				flags &= ~AI_CANONNAME;
    785 			break;
    786 #ifdef INET6
    787 		case AF_INET6:
    788 			pfx = ((struct in6_addr *)pton)->s6_addr[0];
    789 			if (pfx == 0 || pfx == 0xfe || pfx == 0xff)
    790 				flags &= ~AI_CANONNAME;
    791 			break;
    792 #endif
    793 		}
    794 
    795 		if (pai->ai_family == afd->a_af ||
    796 		    pai->ai_family == PF_UNSPEC /*?*/) {
    797 			if ((flags & AI_CANONNAME) == 0) {
    798 				GET_AI(cur->ai_next, afd, pton);
    799 				GET_PORT(cur->ai_next, servname);
    800 			} else {
    801 				/*
    802 				 * if AI_CANONNAME and if reverse lookup
    803 				 * fail, return ai anyway to pacify
    804 				 * calling application.
    805 				 *
    806 				 * XXX getaddrinfo() is a name->address
    807 				 * translation function, and it looks
    808 				 * strange that we do addr->name
    809 				 * translation here.
    810 				 */
    811 				get_name(pton, afd, &cur->ai_next,
    812 					pton, pai, servname);
    813 			}
    814 			while (cur && cur->ai_next)
    815 				cur = cur->ai_next;
    816 		} else
    817 			ERR(EAI_FAMILY);	/*xxx*/
    818 	}
    819 
    820 	*res = sentinel.ai_next;
    821 	return 0;
    822 
    823 free:
    824 bad:
    825 	if (sentinel.ai_next)
    826 		freeaddrinfo(sentinel.ai_next);
    827 	return error;
    828 }
    829 
    830 /*
    831  * numeric hostname with scope
    832  */
    833 static int
    834 explore_numeric_scope(pai, hostname, servname, res)
    835 	const struct addrinfo *pai;
    836 	const char *hostname;
    837 	const char *servname;
    838 	struct addrinfo **res;
    839 {
    840 #ifndef SCOPE_DELIMITER
    841 	return explore_numeric(pai, hostname, servname, res);
    842 #else
    843 	const struct afd *afd;
    844 	struct addrinfo *cur;
    845 	int error;
    846 	char *cp, *hostname2 = NULL;
    847 	int scope;
    848 	struct sockaddr_in6 *sin6;
    849 
    850 	/*
    851 	 * if the servname does not match socktype/protocol, ignore it.
    852 	 */
    853 	if (get_portmatch(pai, servname) != 0)
    854 		return 0;
    855 
    856 	afd = find_afd(pai->ai_family);
    857 	if (!afd->a_scoped)
    858 		return explore_numeric(pai, hostname, servname, res);
    859 
    860 	cp = strchr(hostname, SCOPE_DELIMITER);
    861 	if (cp == NULL)
    862 		return explore_numeric(pai, hostname, servname, res);
    863 
    864 	/*
    865 	 * Handle special case of <scoped_address><delimiter><scope id>
    866 	 */
    867 	hostname2 = strdup(hostname);
    868 	if (hostname2 == NULL)
    869 		return EAI_MEMORY;
    870 	/* terminate at the delimiter */
    871 	hostname2[cp - hostname] = '\0';
    872 
    873 	cp++;
    874 	switch (pai->ai_family) {
    875 #ifdef INET6
    876 	case AF_INET6:
    877 		scope = if_nametoindex(cp);
    878 		if (scope == 0) {
    879 			free(hostname2);
    880 			return (EAI_NONAME);
    881 		}
    882 		break;
    883 #endif
    884 	}
    885 
    886 	error = explore_numeric(pai, hostname2, servname, res);
    887 	if (error == 0) {
    888 		for (cur = *res; cur; cur = cur->ai_next) {
    889 			if (cur->ai_family != AF_INET6)
    890 				continue;
    891 			sin6 = (struct sockaddr_in6 *)cur->ai_addr;
    892 			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
    893 			    IN6_IS_ADDR_MC_LINKLOCAL(&sin6->sin6_addr))
    894 				sin6->sin6_scope_id = scope;
    895 		}
    896 	}
    897 
    898 	free(hostname2);
    899 
    900 	return error;
    901 #endif
    902 }
    903 
    904 static int
    905 get_name(addr, afd, res, numaddr, pai, servname)
    906 	const char *addr;
    907 	const struct afd *afd;
    908 	struct addrinfo **res;
    909 	char *numaddr;
    910 	const struct addrinfo *pai;
    911 	const char *servname;
    912 {
    913 	struct hostent *hp = NULL;
    914 	struct addrinfo *cur = NULL;
    915 	int error = 0;
    916 	char *ap = NULL, *cn = NULL;
    917 #ifdef USE_GETIPNODEBY
    918 	int h_error;
    919 
    920 	hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
    921 #else
    922 	hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
    923 #endif
    924 	if (hp && hp->h_name && hp->h_name[0] && hp->h_addr_list[0]) {
    925 #ifdef USE_GETIPNODEBY
    926 		GET_AI(cur, afd, hp->h_addr_list[0]);
    927 		GET_PORT(cur, servname);
    928 		GET_CANONNAME(cur, hp->h_name);
    929 #else
    930 		/* hp will be damaged if we use gethostbyaddr() */
    931 		if ((ap = (char *)malloc(hp->h_length)) == NULL) {
    932 			error = EAI_MEMORY;
    933 			goto free;
    934 		}
    935 		memcpy(ap, hp->h_addr_list[0], hp->h_length);
    936 		if ((cn = strdup(hp->h_name)) == NULL) {
    937 			error = EAI_MEMORY;
    938 			goto free;
    939 		}
    940 
    941 		GET_AI(cur, afd, ap);
    942 		GET_PORT(cur, servname);
    943 		GET_CANONNAME(cur, cn);
    944 		free(ap); ap = NULL;
    945 		free(cn); cn = NULL;
    946 #endif
    947 	} else {
    948 		GET_AI(cur, afd, numaddr);
    949 		GET_PORT(cur, servname);
    950 	}
    951 
    952 #ifdef USE_GETIPNODEBY
    953 	if (hp)
    954 		freehostent(hp);
    955 #endif
    956 	*res = cur;
    957 	return SUCCESS;
    958  free:
    959 	if (cur)
    960 		freeaddrinfo(cur);
    961 	if (ap)
    962 		free(ap);
    963 	if (cn)
    964 		free(cn);
    965 #ifdef USE_GETIPNODEBY
    966 	if (hp)
    967 		freehostent(hp);
    968 #endif
    969 	*res = NULL;
    970 	return error;
    971 }
    972 
    973 static int
    974 get_canonname(pai, ai, str)
    975 	const struct addrinfo *pai;
    976 	struct addrinfo *ai;
    977 	const char *str;
    978 {
    979 	if ((pai->ai_flags & AI_CANONNAME) != 0) {
    980 		ai->ai_canonname = (char *)malloc(strlen(str) + 1);
    981 		if (ai->ai_canonname == NULL)
    982 			return EAI_MEMORY;
    983 		strcpy(ai->ai_canonname, str);
    984 	}
    985 	return 0;
    986 }
    987 
    988 static struct addrinfo *
    989 get_ai(pai, afd, addr)
    990 	const struct addrinfo *pai;
    991 	const struct afd *afd;
    992 	const char *addr;
    993 {
    994 	char *p;
    995 	struct addrinfo *ai;
    996 
    997 	ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
    998 		+ (afd->a_socklen));
    999 	if (ai == NULL)
   1000 		return NULL;
   1001 
   1002 	memcpy(ai, pai, sizeof(struct addrinfo));
   1003 	ai->ai_addr = (struct sockaddr *)(ai + 1);
   1004 	memset(ai->ai_addr, 0, afd->a_socklen);
   1005 #ifdef HAVE_SOCKADDR_SA_LEN
   1006 	ai->ai_addr->sa_len = afd->a_socklen;
   1007 #endif
   1008 	ai->ai_addrlen = afd->a_socklen;
   1009 	ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
   1010 	p = (char *)(ai->ai_addr);
   1011 	memcpy(p + afd->a_off, addr, afd->a_addrlen);
   1012 	return ai;
   1013 }
   1014 
   1015 static int
   1016 get_portmatch(ai, servname)
   1017 	const struct addrinfo *ai;
   1018 	const char *servname;
   1019 {
   1020 
   1021 	/* get_port does not touch first argument. when matchonly == 1. */
   1022 	return get_port((struct addrinfo *)ai, servname, 1);
   1023 }
   1024 
   1025 static int
   1026 get_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 *)ai->ai_addr)->sin_port = port;
   1090 			break;
   1091 #ifdef INET6
   1092 		case AF_INET6:
   1093 			((struct sockaddr_in6 *)ai->ai_addr)->sin6_port = port;
   1094 			break;
   1095 #endif
   1096 		}
   1097 	}
   1098 
   1099 	return 0;
   1100 }
   1101 
   1102 static const struct afd *
   1103 find_afd(af)
   1104 	int af;
   1105 {
   1106 	const struct afd *afd;
   1107 
   1108 	if (af == PF_UNSPEC)
   1109 		return NULL;
   1110 	for (afd = afdl; afd->a_af; afd++) {
   1111 		if (afd->a_af == af)
   1112 			return afd;
   1113 	}
   1114 	return NULL;
   1115 }
   1116