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getnameinfo.c revision 1.50.6.3 
      1 /*	$NetBSD: getnameinfo.c,v 1.50.6.3 2014/05/22 11:36:53 yamt Exp $	*/
      2 /*	$KAME: getnameinfo.c,v 1.45 2000/09/25 22:43:56 itojun Exp $	*/
      3 
      4 /*
      5  * Copyright (c) 2000 Ben Harris.
      6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
      7  * All rights reserved.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. Neither the name of the project nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 /*
     35  * Issues to be discussed:
     36  * - Thread safe-ness must be checked
     37  * - RFC2553 says that we should raise error on short buffer.  X/Open says
     38  *   we need to truncate the result.  We obey RFC2553 (and X/Open should be
     39  *   modified).  ipngwg rough consensus seems to follow RFC2553.
     40  * - What is "local" in NI_FQDN?
     41  * - NI_NAMEREQD and NI_NUMERICHOST conflict with each other.
     42  * - (KAME extension) always attach textual scopeid (fe80::1%lo0), if
     43  *   sin6_scope_id is filled - standardization status?
     44  *   XXX breaks backward compat for code that expects no scopeid.
     45  *   beware on merge.
     46  */
     47 
     48 #include <sys/cdefs.h>
     49 #if defined(LIBC_SCCS) && !defined(lint)
     50 __RCSID("$NetBSD: getnameinfo.c,v 1.50.6.3 2014/05/22 11:36:53 yamt Exp $");
     51 #endif /* LIBC_SCCS and not lint */
     52 
     53 #include "namespace.h"
     54 #include <sys/types.h>
     55 #include <sys/socket.h>
     56 #include <sys/un.h>
     57 #include <net/if.h>
     58 #include <net/if_dl.h>
     59 #include <net/if_ieee1394.h>
     60 #include <net/if_types.h>
     61 #include <netatalk/at.h>
     62 #include <netinet/in.h>
     63 #include <arpa/inet.h>
     64 #include <arpa/nameser.h>
     65 #include <assert.h>
     66 #include <limits.h>
     67 #include <netdb.h>
     68 #include <resolv.h>
     69 #include <stddef.h>
     70 #include <string.h>
     71 
     72 #include "servent.h"
     73 #include "hostent.h"
     74 
     75 #ifdef __weak_alias
     76 __weak_alias(getnameinfo,_getnameinfo)
     77 #endif
     78 
     79 static const struct afd {
     80 	int		a_af;
     81 	socklen_t	a_addrlen;
     82 	socklen_t	a_socklen;
     83 	int		a_off;
     84 } afdl [] = {
     85 #ifdef INET6
     86 	{PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
     87 		offsetof(struct sockaddr_in6, sin6_addr)},
     88 #endif
     89 	{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
     90 		offsetof(struct sockaddr_in, sin_addr)},
     91 	{0, 0, 0, 0},
     92 };
     93 
     94 struct sockinet {
     95 	u_char	si_len;
     96 	u_char	si_family;
     97 	u_short	si_port;
     98 };
     99 
    100 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *,
    101     socklen_t, char *, socklen_t, int);
    102 #ifdef INET6
    103 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *,
    104 				 socklen_t, int);
    105 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int);
    106 #endif
    107 static int getnameinfo_atalk(const struct sockaddr *, socklen_t, char *,
    108     socklen_t, char *, socklen_t, int);
    109 static int getnameinfo_local(const struct sockaddr *, socklen_t, char *,
    110     socklen_t, char *, socklen_t, int);
    111 
    112 static int getnameinfo_link(const struct sockaddr *, socklen_t, char *,
    113     socklen_t, char *, socklen_t, int);
    114 static int hexname(const uint8_t *, size_t, char *, socklen_t);
    115 
    116 /*
    117  * Top-level getnameinfo() code.  Look at the address family, and pick an
    118  * appropriate function to call.
    119  */
    120 int
    121 getnameinfo(const struct sockaddr *sa, socklen_t salen,
    122 	char *host, socklen_t hostlen,
    123 	char *serv, socklen_t servlen,
    124 	int flags)
    125 {
    126 
    127 	switch (sa->sa_family) {
    128 	case AF_APPLETALK:
    129 		return getnameinfo_atalk(sa, salen, host, hostlen,
    130 		    serv, servlen, flags);
    131 	case AF_INET:
    132 	case AF_INET6:
    133 		return getnameinfo_inet(sa, salen, host, hostlen,
    134 		    serv, servlen, flags);
    135 	case AF_LINK:
    136 		return getnameinfo_link(sa, salen, host, hostlen,
    137 		    serv, servlen, flags);
    138 	case AF_LOCAL:
    139 		return getnameinfo_local(sa, salen, host, hostlen,
    140 		    serv, servlen, flags);
    141 	default:
    142 		return EAI_FAMILY;
    143 	}
    144 }
    145 
    146 /*
    147  * getnameinfo_atalk():
    148  * Format an AppleTalk address into a printable format.
    149  */
    150 /* ARGSUSED */
    151 static int
    152 getnameinfo_atalk(const struct sockaddr *sa, socklen_t salen,
    153     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
    154     int flags)
    155 {
    156 	char numserv[8];
    157 	int n, m=0;
    158 
    159 	const struct sockaddr_at *sat =
    160 	    (const struct sockaddr_at *)(const void *)sa;
    161 
    162 	if (serv != NULL && servlen > 0) {
    163 		snprintf(numserv, sizeof(numserv), "%u", sat->sat_port);
    164 		if (strlen(numserv) + 1 > servlen)
    165 			return EAI_MEMORY;
    166 		strlcpy(serv, numserv, servlen);
    167 	}
    168 
    169         n = snprintf(host, hostlen, "%u.%u",
    170 	    ntohs(sat->sat_addr.s_net), sat->sat_addr.s_node);
    171 
    172 	if (n < 0 || (socklen_t)(m+n) >= hostlen)
    173 		goto errout;
    174 
    175 	m += n;
    176 
    177 	if (sat->sat_range.r_netrange.nr_phase) {
    178         	n = snprintf(host+m, hostlen-m, " phase %u",
    179 			sat->sat_range.r_netrange.nr_phase);
    180 
    181 		if (n < 0 || (socklen_t)(m+n) >= hostlen)
    182 			goto errout;
    183 
    184 		m += n;
    185 	}
    186 	if (sat->sat_range.r_netrange.nr_firstnet) {
    187         	n = snprintf(host+m, hostlen-m, " range %u - %u",
    188 			ntohs(sat->sat_range.r_netrange.nr_firstnet),
    189 			ntohs(sat->sat_range.r_netrange.nr_lastnet ));
    190 
    191 		if (n < 0 || (socklen_t)(m+n) >= hostlen)
    192 			goto errout;
    193 
    194 		m += n;
    195 	}
    196 
    197 	return 0;
    198 
    199 errout:
    200 	if (host && hostlen>0)
    201 		host[m] = '\0';	/* XXX ??? */
    202 
    203 	return EAI_MEMORY;
    204 }
    205 
    206 /*
    207  * getnameinfo_local():
    208  * Format an local address into a printable format.
    209  */
    210 /* ARGSUSED */
    211 static int
    212 getnameinfo_local(const struct sockaddr *sa, socklen_t salen,
    213     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
    214     int flags)
    215 {
    216 	const struct sockaddr_un *sun =
    217 	    (const struct sockaddr_un *)(const void *)sa;
    218 
    219 	if (serv != NULL && servlen > 0)
    220 		serv[0] = '\0';
    221 
    222 	if (host && hostlen > 0)
    223 		strlcpy(host, sun->sun_path,
    224 		    MIN(sizeof(sun->sun_path) + 1, hostlen));
    225 
    226 	return 0;
    227 }
    228 
    229 /*
    230  * getnameinfo_inet():
    231  * Format an IPv4 or IPv6 sockaddr into a printable string.
    232  */
    233 static int
    234 getnameinfo_inet(const struct sockaddr *sa, socklen_t salen,
    235 	char *host, socklen_t hostlen,
    236 	char *serv, socklen_t servlen,
    237 	int flags)
    238 {
    239 	const struct afd *afd;
    240 	struct servent *sp;
    241 	struct hostent *hp;
    242 	u_short port;
    243 	int family, i;
    244 	const char *addr;
    245 	uint32_t v4a;
    246 	char numserv[512];
    247 	char numaddr[512];
    248 
    249 	/* sa is checked below */
    250 	/* host may be NULL */
    251 	/* serv may be NULL */
    252 
    253 	if (sa == NULL)
    254 		return EAI_FAIL;
    255 
    256 	family = sa->sa_family;
    257 	for (i = 0; afdl[i].a_af; i++)
    258 		if (afdl[i].a_af == family) {
    259 			afd = &afdl[i];
    260 			goto found;
    261 		}
    262 	return EAI_FAMILY;
    263 
    264  found:
    265 	if (salen != afd->a_socklen)
    266 		return EAI_FAIL;
    267 
    268 	/* network byte order */
    269 	port = ((const struct sockinet *)(const void *)sa)->si_port;
    270 	addr = (const char *)(const void *)sa + afd->a_off;
    271 
    272 	if (serv == NULL || servlen == 0) {
    273 		/*
    274 		 * do nothing in this case.
    275 		 * in case you are wondering if "&&" is more correct than
    276 		 * "||" here: rfc2553bis-03 says that serv == NULL OR
    277 		 * servlen == 0 means that the caller does not want the result.
    278 		 */
    279 	} else {
    280 		struct servent_data svd;
    281 		struct servent sv;
    282 
    283 		if (flags & NI_NUMERICSERV)
    284 			sp = NULL;
    285 		else {
    286 			(void)memset(&svd, 0, sizeof(svd));
    287 			sp = getservbyport_r(port,
    288 				(flags & NI_DGRAM) ? "udp" : "tcp", &sv, &svd);
    289 		}
    290 		if (sp) {
    291 			if (strlen(sp->s_name) + 1 > servlen) {
    292 				endservent_r(&svd);
    293 				return EAI_MEMORY;
    294 			}
    295 			strlcpy(serv, sp->s_name, servlen);
    296 			endservent_r(&svd);
    297 		} else {
    298 			snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
    299 			if (strlen(numserv) + 1 > servlen)
    300 				return EAI_MEMORY;
    301 			strlcpy(serv, numserv, servlen);
    302 		}
    303 	}
    304 
    305 	switch (sa->sa_family) {
    306 	case AF_INET:
    307 		v4a = (uint32_t)
    308 		    ntohl(((const struct sockaddr_in *)
    309 		    (const void *)sa)->sin_addr.s_addr);
    310 		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
    311 			flags |= NI_NUMERICHOST;
    312 		v4a >>= IN_CLASSA_NSHIFT;
    313 		if (v4a == 0)
    314 			flags |= NI_NUMERICHOST;
    315 		break;
    316 #ifdef INET6
    317 	case AF_INET6:
    318 	    {
    319 		const struct sockaddr_in6 *sin6;
    320 		sin6 = (const struct sockaddr_in6 *)(const void *)sa;
    321 		switch (sin6->sin6_addr.s6_addr[0]) {
    322 		case 0x00:
    323 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
    324 				;
    325 			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
    326 				;
    327 			else
    328 				flags |= NI_NUMERICHOST;
    329 			break;
    330 		default:
    331 			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
    332 				flags |= NI_NUMERICHOST;
    333 			}
    334 			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
    335 				flags |= NI_NUMERICHOST;
    336 			break;
    337 		}
    338 	    }
    339 		break;
    340 #endif
    341 	}
    342 	if (host == NULL || hostlen == 0) {
    343 		/*
    344 		 * do nothing in this case.
    345 		 * in case you are wondering if "&&" is more correct than
    346 		 * "||" here: rfc2553bis-03 says that host == NULL or
    347 		 * hostlen == 0 means that the caller does not want the result.
    348 		 */
    349 	} else if (flags & NI_NUMERICHOST) {
    350 		size_t numaddrlen;
    351 
    352 		/* NUMERICHOST and NAMEREQD conflicts with each other */
    353 		if (flags & NI_NAMEREQD)
    354 			return EAI_NONAME;
    355 
    356 		switch(afd->a_af) {
    357 #ifdef INET6
    358 		case AF_INET6:
    359 		{
    360 			int error;
    361 
    362 			if ((error = ip6_parsenumeric(sa, addr, host,
    363 						      hostlen, flags)) != 0)
    364 				return(error);
    365 			break;
    366 		}
    367 #endif
    368 		default:
    369 			if (inet_ntop(afd->a_af, addr, numaddr,
    370 			    (socklen_t)sizeof(numaddr)) == NULL)
    371 				return EAI_SYSTEM;
    372 			numaddrlen = strlen(numaddr);
    373 			if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    374 				return EAI_MEMORY;
    375 			strlcpy(host, numaddr, hostlen);
    376 			break;
    377 		}
    378 	} else {
    379 		struct hostent hent;
    380 		char hbuf[4096];
    381 		int he;
    382 		hp = gethostbyaddr_r(addr, afd->a_addrlen, afd->a_af, &hent,
    383 		    hbuf, sizeof(hbuf), &he);
    384 
    385 		if (hp) {
    386 #if 0
    387 			/*
    388 			 * commented out, since "for local host" is not
    389 			 * implemented here - see RFC2553 p30
    390 			 */
    391 			if (flags & NI_NOFQDN) {
    392 				char *p;
    393 				p = strchr(hp->h_name, '.');
    394 				if (p)
    395 					*p = '\0';
    396 			}
    397 #endif
    398 			if (strlen(hp->h_name) + 1 > hostlen) {
    399 				return EAI_MEMORY;
    400 			}
    401 			strlcpy(host, hp->h_name, hostlen);
    402 		} else {
    403 			if (flags & NI_NAMEREQD)
    404 				return EAI_NONAME;
    405 			switch(afd->a_af) {
    406 #ifdef INET6
    407 			case AF_INET6:
    408 			{
    409 				int error;
    410 
    411 				if ((error = ip6_parsenumeric(sa, addr, host,
    412 							      hostlen,
    413 							      flags)) != 0)
    414 					return(error);
    415 				break;
    416 			}
    417 #endif
    418 			default:
    419 				if (inet_ntop(afd->a_af, addr, host,
    420 				    hostlen) == NULL)
    421 					return EAI_SYSTEM;
    422 				break;
    423 			}
    424 		}
    425 	}
    426 	return(0);
    427 }
    428 
    429 #ifdef INET6
    430 static int
    431 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host,
    432 	socklen_t hostlen, int flags)
    433 {
    434 	size_t numaddrlen;
    435 	char numaddr[512];
    436 
    437 	_DIAGASSERT(sa != NULL);
    438 	_DIAGASSERT(addr != NULL);
    439 	_DIAGASSERT(host != NULL);
    440 
    441 	if (inet_ntop(AF_INET6, addr, numaddr, (socklen_t)sizeof(numaddr))
    442 	    == NULL)
    443 		return EAI_SYSTEM;
    444 
    445 	numaddrlen = strlen(numaddr);
    446 	if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    447 		return EAI_OVERFLOW;
    448 	strlcpy(host, numaddr, hostlen);
    449 
    450 	if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
    451 		char zonebuf[MAXHOSTNAMELEN];
    452 		int zonelen;
    453 
    454 		zonelen = ip6_sa2str(
    455 		    (const struct sockaddr_in6 *)(const void *)sa,
    456 		    zonebuf, sizeof(zonebuf), flags);
    457 		if (zonelen < 0)
    458 			return EAI_OVERFLOW;
    459 		if ((size_t) zonelen + 1 + numaddrlen + 1 > hostlen)
    460 			return EAI_OVERFLOW;
    461 		/* construct <numeric-addr><delim><zoneid> */
    462 		memcpy(host + numaddrlen + 1, zonebuf,
    463 		    (size_t)zonelen);
    464 		host[numaddrlen] = SCOPE_DELIMITER;
    465 		host[numaddrlen + 1 + zonelen] = '\0';
    466 	}
    467 
    468 	return 0;
    469 }
    470 
    471 /* ARGSUSED */
    472 static int
    473 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags)
    474 {
    475 	unsigned int ifindex;
    476 	const struct in6_addr *a6;
    477 	int n;
    478 
    479 	_DIAGASSERT(sa6 != NULL);
    480 	_DIAGASSERT(buf != NULL);
    481 
    482 	ifindex = (unsigned int)sa6->sin6_scope_id;
    483 	a6 = &sa6->sin6_addr;
    484 
    485 #ifdef NI_NUMERICSCOPE
    486 	if ((flags & NI_NUMERICSCOPE) != 0) {
    487 		n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    488 		if (n < 0 || (size_t)n >= bufsiz)
    489 			return -1;
    490 		else
    491 			return n;
    492 	}
    493 #endif
    494 
    495 	/* if_indextoname() does not take buffer size.  not a good api... */
    496 	if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
    497 	    bufsiz >= IF_NAMESIZE) {
    498 		char *p = if_indextoname(ifindex, buf);
    499 		if (p) {
    500 			return (int)strlen(p);
    501 		}
    502 	}
    503 
    504 	/* last resort */
    505 	n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    506 	if (n < 0 || (size_t) n >= bufsiz)
    507 		return -1;
    508 	else
    509 		return n;
    510 }
    511 #endif /* INET6 */
    512 
    513 
    514 /*
    515  * getnameinfo_link():
    516  * Format a link-layer address into a printable format, paying attention to
    517  * the interface type.
    518  */
    519 /* ARGSUSED */
    520 static int
    521 getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
    522     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
    523     int flags)
    524 {
    525 	const struct sockaddr_dl *sdl =
    526 	    (const struct sockaddr_dl *)(const void *)sa;
    527 	const struct ieee1394_hwaddr *iha;
    528 	int n;
    529 
    530 	if (serv != NULL && servlen > 0)
    531 		*serv = '\0';
    532 
    533 	if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
    534 		n = snprintf(host, hostlen, "link#%u", sdl->sdl_index);
    535 		if (n < 0 || (socklen_t) n > hostlen) {
    536 			*host = '\0';
    537 			return EAI_MEMORY;
    538 		}
    539 		return 0;
    540 	}
    541 
    542 	switch (sdl->sdl_type) {
    543 #ifdef IFT_ECONET
    544 	case IFT_ECONET:
    545 		if (sdl->sdl_alen < 2)
    546 			return EAI_FAMILY;
    547 		if (CLLADDR(sdl)[1] == 0)
    548 			n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]);
    549 		else
    550 			n = snprintf(host, hostlen, "%u.%u",
    551 			    CLLADDR(sdl)[1], CLLADDR(sdl)[0]);
    552 		if (n < 0 || (socklen_t) n >= hostlen) {
    553 			*host = '\0';
    554 			return EAI_MEMORY;
    555 		} else
    556 			return 0;
    557 #endif
    558 	case IFT_IEEE1394:
    559 		if (sdl->sdl_alen < sizeof(iha->iha_uid))
    560 			return EAI_FAMILY;
    561 		iha =
    562 		    (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl);
    563 		return hexname(iha->iha_uid, sizeof(iha->iha_uid),
    564 		    host, hostlen);
    565 	/*
    566 	 * The following have zero-length addresses.
    567 	 * IFT_ATM	(net/if_atmsubr.c)
    568 	 * IFT_FAITH	(net/if_faith.c)
    569 	 * IFT_GIF	(net/if_gif.c)
    570 	 * IFT_LOOP	(net/if_loop.c)
    571 	 * IFT_PPP	(net/if_ppp.c, net/if_spppsubr.c)
    572 	 * IFT_SLIP	(net/if_sl.c, net/if_strip.c)
    573 	 * IFT_STF	(net/if_stf.c)
    574 	 * IFT_L2VLAN	(net/if_vlan.c)
    575 	 * IFT_PROPVIRTUAL (net/if_bridge.h>
    576 	 */
    577 	/*
    578 	 * The following use IPv4 addresses as link-layer addresses:
    579 	 * IFT_OTHER	(net/if_gre.c)
    580 	 */
    581 	case IFT_ARCNET: /* default below is believed correct for all these. */
    582 	case IFT_ETHER:
    583 	case IFT_FDDI:
    584 	case IFT_HIPPI:
    585 	case IFT_ISO88025:
    586 	default:
    587 		return hexname((const uint8_t *)CLLADDR(sdl),
    588 		    (size_t)sdl->sdl_alen, host, hostlen);
    589 	}
    590 }
    591 
    592 static int
    593 hexname(const uint8_t *cp, size_t len, char *host, socklen_t hostlen)
    594 {
    595 	int n;
    596 	size_t i;
    597 	char *outp = host;
    598 
    599 	*outp = '\0';
    600 	for (i = 0; i < len; i++) {
    601 		n = snprintf(outp, hostlen, "%s%02x",
    602 		    i ? ":" : "", cp[i]);
    603 		if (n < 0 || (socklen_t) n >= hostlen) {
    604 			*host = '\0';
    605 			return EAI_MEMORY;
    606 		}
    607 		outp += n;
    608 		hostlen -= n;
    609 	}
    610 	return 0;
    611 }
    612