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getnameinfo.c revision 1.53 
      1 /*	$NetBSD: getnameinfo.c,v 1.53 2012/09/26 23:13:00 christos 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 1.53 2012/09/26 23:13:00 christos 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 
     74 #ifdef __weak_alias
     75 __weak_alias(getnameinfo,_getnameinfo)
     76 #endif
     77 
     78 static const struct afd {
     79 	int		a_af;
     80 	socklen_t	a_addrlen;
     81 	socklen_t	a_socklen;
     82 	int		a_off;
     83 } afdl [] = {
     84 #ifdef INET6
     85 	{PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
     86 		offsetof(struct sockaddr_in6, sin6_addr)},
     87 #endif
     88 	{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
     89 		offsetof(struct sockaddr_in, sin_addr)},
     90 	{0, 0, 0, 0},
     91 };
     92 
     93 struct sockinet {
     94 	u_char	si_len;
     95 	u_char	si_family;
     96 	u_short	si_port;
     97 };
     98 
     99 static int getnameinfo_inet(const struct sockaddr *, socklen_t, char *,
    100     socklen_t, char *, socklen_t, int);
    101 #ifdef INET6
    102 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *,
    103 				 socklen_t, int);
    104 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int);
    105 #endif
    106 static int getnameinfo_atalk(const struct sockaddr *, socklen_t, char *,
    107     socklen_t, char *, socklen_t, int);
    108 static int getnameinfo_local(const struct sockaddr *, socklen_t, char *,
    109     socklen_t, char *, socklen_t, int);
    110 
    111 static int getnameinfo_link(const struct sockaddr *, socklen_t, char *,
    112     socklen_t, char *, socklen_t, int);
    113 static int hexname(const uint8_t *, size_t, char *, socklen_t);
    114 
    115 /*
    116  * Top-level getnameinfo() code.  Look at the address family, and pick an
    117  * appropriate function to call.
    118  */
    119 int
    120 getnameinfo(const struct sockaddr *sa, socklen_t salen,
    121 	char *host, socklen_t hostlen,
    122 	char *serv, socklen_t servlen,
    123 	int flags)
    124 {
    125 
    126 	switch (sa->sa_family) {
    127 	case AF_APPLETALK:
    128 		return getnameinfo_atalk(sa, salen, host, hostlen,
    129 		    serv, servlen, flags);
    130 	case AF_INET:
    131 	case AF_INET6:
    132 		return getnameinfo_inet(sa, salen, host, hostlen,
    133 		    serv, servlen, flags);
    134 	case AF_LINK:
    135 		return getnameinfo_link(sa, salen, host, hostlen,
    136 		    serv, servlen, flags);
    137 	case AF_LOCAL:
    138 		return getnameinfo_local(sa, salen, host, hostlen,
    139 		    serv, servlen, flags);
    140 	default:
    141 		return EAI_FAMILY;
    142 	}
    143 }
    144 
    145 /*
    146  * getnameinfo_atalk():
    147  * Format an AppleTalk address into a printable format.
    148  */
    149 /* ARGSUSED */
    150 static int
    151 getnameinfo_atalk(const struct sockaddr *sa, socklen_t salen,
    152     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
    153     int flags)
    154 {
    155 	char numserv[8];
    156 	int n, m=0;
    157 
    158 	const struct sockaddr_at *sat =
    159 	    (const struct sockaddr_at *)(const void *)sa;
    160 
    161 	if (serv != NULL && servlen > 0) {
    162 		snprintf(numserv, sizeof(numserv), "%u", sat->sat_port);
    163 		if (strlen(numserv) + 1 > servlen)
    164 			return EAI_MEMORY;
    165 		strlcpy(serv, numserv, servlen);
    166 	}
    167 
    168         n = snprintf(host, hostlen, "%u.%u",
    169 	    ntohs(sat->sat_addr.s_net), sat->sat_addr.s_node);
    170 
    171 	if (n < 0 || (socklen_t)(m+n) >= hostlen)
    172 		goto errout;
    173 
    174 	m += n;
    175 
    176 	if (sat->sat_range.r_netrange.nr_phase) {
    177         	n = snprintf(host+m, hostlen-m, " phase %u",
    178 			sat->sat_range.r_netrange.nr_phase);
    179 
    180 		if (n < 0 || (socklen_t)(m+n) >= hostlen)
    181 			goto errout;
    182 
    183 		m += n;
    184 	}
    185 	if (sat->sat_range.r_netrange.nr_firstnet) {
    186         	n = snprintf(host+m, hostlen-m, " range %u - %u",
    187 			ntohs(sat->sat_range.r_netrange.nr_firstnet),
    188 			ntohs(sat->sat_range.r_netrange.nr_lastnet ));
    189 
    190 		if (n < 0 || (socklen_t)(m+n) >= hostlen)
    191 			goto errout;
    192 
    193 		m += n;
    194 	}
    195 
    196 	return 0;
    197 
    198 errout:
    199 	if (host && hostlen>0)
    200 		host[m] = '\0';	/* XXX ??? */
    201 
    202 	return EAI_MEMORY;
    203 }
    204 
    205 /*
    206  * getnameinfo_local():
    207  * Format an local address into a printable format.
    208  */
    209 /* ARGSUSED */
    210 static int
    211 getnameinfo_local(const struct sockaddr *sa, socklen_t salen,
    212     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
    213     int flags)
    214 {
    215 	const struct sockaddr_un *sun =
    216 	    (const struct sockaddr_un *)(const void *)sa;
    217 
    218 	if (serv != NULL && servlen > 0)
    219 		serv[0] = '\0';
    220 
    221 	if (host && hostlen > 0)
    222 		strlcpy(host, sun->sun_path,
    223 		    MIN(sizeof(sun->sun_path) + 1, hostlen));
    224 
    225 	return 0;
    226 }
    227 
    228 /*
    229  * getnameinfo_inet():
    230  * Format an IPv4 or IPv6 sockaddr into a printable string.
    231  */
    232 static int
    233 getnameinfo_inet(const struct sockaddr *sa, socklen_t salen,
    234 	char *host, socklen_t hostlen,
    235 	char *serv, socklen_t servlen,
    236 	int flags)
    237 {
    238 	const struct afd *afd;
    239 	struct servent *sp;
    240 	struct hostent *hp;
    241 	u_short port;
    242 	int family, i;
    243 	const char *addr;
    244 	uint32_t v4a;
    245 	char numserv[512];
    246 	char numaddr[512];
    247 
    248 	/* sa is checked below */
    249 	/* host may be NULL */
    250 	/* serv may be NULL */
    251 
    252 	if (sa == NULL)
    253 		return EAI_FAIL;
    254 
    255 	family = sa->sa_family;
    256 	for (i = 0; afdl[i].a_af; i++)
    257 		if (afdl[i].a_af == family) {
    258 			afd = &afdl[i];
    259 			goto found;
    260 		}
    261 	return EAI_FAMILY;
    262 
    263  found:
    264 	if (salen != afd->a_socklen)
    265 		return EAI_FAIL;
    266 
    267 	/* network byte order */
    268 	port = ((const struct sockinet *)(const void *)sa)->si_port;
    269 	addr = (const char *)(const void *)sa + afd->a_off;
    270 
    271 	if (serv == NULL || servlen == 0) {
    272 		/*
    273 		 * do nothing in this case.
    274 		 * in case you are wondering if "&&" is more correct than
    275 		 * "||" here: rfc2553bis-03 says that serv == NULL OR
    276 		 * servlen == 0 means that the caller does not want the result.
    277 		 */
    278 	} else {
    279 		struct servent_data svd;
    280 		struct servent sv;
    281 
    282 		if (flags & NI_NUMERICSERV)
    283 			sp = NULL;
    284 		else {
    285 			(void)memset(&svd, 0, sizeof(svd));
    286 			sp = getservbyport_r(port,
    287 				(flags & NI_DGRAM) ? "udp" : "tcp", &sv, &svd);
    288 		}
    289 		if (sp) {
    290 			if (strlen(sp->s_name) + 1 > servlen) {
    291 				endservent_r(&svd);
    292 				return EAI_MEMORY;
    293 			}
    294 			strlcpy(serv, sp->s_name, servlen);
    295 			endservent_r(&svd);
    296 		} else {
    297 			snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
    298 			if (strlen(numserv) + 1 > servlen)
    299 				return EAI_MEMORY;
    300 			strlcpy(serv, numserv, servlen);
    301 		}
    302 	}
    303 
    304 	switch (sa->sa_family) {
    305 	case AF_INET:
    306 		v4a = (uint32_t)
    307 		    ntohl(((const struct sockaddr_in *)
    308 		    (const void *)sa)->sin_addr.s_addr);
    309 		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
    310 			flags |= NI_NUMERICHOST;
    311 		v4a >>= IN_CLASSA_NSHIFT;
    312 		if (v4a == 0)
    313 			flags |= NI_NUMERICHOST;
    314 		break;
    315 #ifdef INET6
    316 	case AF_INET6:
    317 	    {
    318 		const struct sockaddr_in6 *sin6;
    319 		sin6 = (const struct sockaddr_in6 *)(const void *)sa;
    320 		switch (sin6->sin6_addr.s6_addr[0]) {
    321 		case 0x00:
    322 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
    323 				;
    324 			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
    325 				;
    326 			else
    327 				flags |= NI_NUMERICHOST;
    328 			break;
    329 		default:
    330 			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
    331 				flags |= NI_NUMERICHOST;
    332 			}
    333 			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
    334 				flags |= NI_NUMERICHOST;
    335 			break;
    336 		}
    337 	    }
    338 		break;
    339 #endif
    340 	}
    341 	if (host == NULL || hostlen == 0) {
    342 		/*
    343 		 * do nothing in this case.
    344 		 * in case you are wondering if "&&" is more correct than
    345 		 * "||" here: rfc2553bis-03 says that host == NULL or
    346 		 * hostlen == 0 means that the caller does not want the result.
    347 		 */
    348 	} else if (flags & NI_NUMERICHOST) {
    349 		size_t numaddrlen;
    350 
    351 		/* NUMERICHOST and NAMEREQD conflicts with each other */
    352 		if (flags & NI_NAMEREQD)
    353 			return EAI_NONAME;
    354 
    355 		switch(afd->a_af) {
    356 #ifdef INET6
    357 		case AF_INET6:
    358 		{
    359 			int error;
    360 
    361 			if ((error = ip6_parsenumeric(sa, addr, host,
    362 						      hostlen, flags)) != 0)
    363 				return(error);
    364 			break;
    365 		}
    366 #endif
    367 		default:
    368 			if (inet_ntop(afd->a_af, addr, numaddr,
    369 			    (socklen_t)sizeof(numaddr)) == NULL)
    370 				return EAI_SYSTEM;
    371 			numaddrlen = strlen(numaddr);
    372 			if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    373 				return EAI_MEMORY;
    374 			strlcpy(host, numaddr, hostlen);
    375 			break;
    376 		}
    377 	} else {
    378 		hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
    379 
    380 		if (hp) {
    381 #if 0
    382 			/*
    383 			 * commented out, since "for local host" is not
    384 			 * implemented here - see RFC2553 p30
    385 			 */
    386 			if (flags & NI_NOFQDN) {
    387 				char *p;
    388 				p = strchr(hp->h_name, '.');
    389 				if (p)
    390 					*p = '\0';
    391 			}
    392 #endif
    393 			if (strlen(hp->h_name) + 1 > hostlen) {
    394 				return EAI_MEMORY;
    395 			}
    396 			strlcpy(host, hp->h_name, hostlen);
    397 		} else {
    398 			if (flags & NI_NAMEREQD)
    399 				return EAI_NONAME;
    400 			switch(afd->a_af) {
    401 #ifdef INET6
    402 			case AF_INET6:
    403 			{
    404 				int error;
    405 
    406 				if ((error = ip6_parsenumeric(sa, addr, host,
    407 							      hostlen,
    408 							      flags)) != 0)
    409 					return(error);
    410 				break;
    411 			}
    412 #endif
    413 			default:
    414 				if (inet_ntop(afd->a_af, addr, host,
    415 				    hostlen) == NULL)
    416 					return EAI_SYSTEM;
    417 				break;
    418 			}
    419 		}
    420 	}
    421 	return(0);
    422 }
    423 
    424 #ifdef INET6
    425 static int
    426 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host,
    427 	socklen_t hostlen, int flags)
    428 {
    429 	size_t numaddrlen;
    430 	char numaddr[512];
    431 
    432 	_DIAGASSERT(sa != NULL);
    433 	_DIAGASSERT(addr != NULL);
    434 	_DIAGASSERT(host != NULL);
    435 
    436 	if (inet_ntop(AF_INET6, addr, numaddr, (socklen_t)sizeof(numaddr))
    437 	    == NULL)
    438 		return EAI_SYSTEM;
    439 
    440 	numaddrlen = strlen(numaddr);
    441 	if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    442 		return EAI_OVERFLOW;
    443 	strlcpy(host, numaddr, hostlen);
    444 
    445 	if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
    446 		char zonebuf[MAXHOSTNAMELEN];
    447 		int zonelen;
    448 
    449 		zonelen = ip6_sa2str(
    450 		    (const struct sockaddr_in6 *)(const void *)sa,
    451 		    zonebuf, sizeof(zonebuf), flags);
    452 		if (zonelen < 0)
    453 			return EAI_OVERFLOW;
    454 		if ((size_t) zonelen + 1 + numaddrlen + 1 > hostlen)
    455 			return EAI_OVERFLOW;
    456 		/* construct <numeric-addr><delim><zoneid> */
    457 		memcpy(host + numaddrlen + 1, zonebuf,
    458 		    (size_t)zonelen);
    459 		host[numaddrlen] = SCOPE_DELIMITER;
    460 		host[numaddrlen + 1 + zonelen] = '\0';
    461 	}
    462 
    463 	return 0;
    464 }
    465 
    466 /* ARGSUSED */
    467 static int
    468 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags)
    469 {
    470 	unsigned int ifindex;
    471 	const struct in6_addr *a6;
    472 	int n;
    473 
    474 	_DIAGASSERT(sa6 != NULL);
    475 	_DIAGASSERT(buf != NULL);
    476 
    477 	ifindex = (unsigned int)sa6->sin6_scope_id;
    478 	a6 = &sa6->sin6_addr;
    479 
    480 #ifdef NI_NUMERICSCOPE
    481 	if ((flags & NI_NUMERICSCOPE) != 0) {
    482 		n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    483 		if (n < 0 || (size_t)n >= bufsiz)
    484 			return -1;
    485 		else
    486 			return n;
    487 	}
    488 #endif
    489 
    490 	/* if_indextoname() does not take buffer size.  not a good api... */
    491 	if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
    492 	    bufsiz >= IF_NAMESIZE) {
    493 		char *p = if_indextoname(ifindex, buf);
    494 		if (p) {
    495 			return (int)strlen(p);
    496 		}
    497 	}
    498 
    499 	/* last resort */
    500 	n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    501 	if (n < 0 || (size_t) n >= bufsiz)
    502 		return -1;
    503 	else
    504 		return n;
    505 }
    506 #endif /* INET6 */
    507 
    508 
    509 /*
    510  * getnameinfo_link():
    511  * Format a link-layer address into a printable format, paying attention to
    512  * the interface type.
    513  */
    514 /* ARGSUSED */
    515 static int
    516 getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
    517     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
    518     int flags)
    519 {
    520 	const struct sockaddr_dl *sdl =
    521 	    (const struct sockaddr_dl *)(const void *)sa;
    522 	const struct ieee1394_hwaddr *iha;
    523 	int n;
    524 
    525 	if (serv != NULL && servlen > 0)
    526 		*serv = '\0';
    527 
    528 	if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
    529 		n = snprintf(host, hostlen, "link#%u", sdl->sdl_index);
    530 		if (n < 0 || (socklen_t) n > hostlen) {
    531 			*host = '\0';
    532 			return EAI_MEMORY;
    533 		}
    534 		return 0;
    535 	}
    536 
    537 	switch (sdl->sdl_type) {
    538 #ifdef IFT_ECONET
    539 	case IFT_ECONET:
    540 		if (sdl->sdl_alen < 2)
    541 			return EAI_FAMILY;
    542 		if (CLLADDR(sdl)[1] == 0)
    543 			n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]);
    544 		else
    545 			n = snprintf(host, hostlen, "%u.%u",
    546 			    CLLADDR(sdl)[1], CLLADDR(sdl)[0]);
    547 		if (n < 0 || (socklen_t) n >= hostlen) {
    548 			*host = '\0';
    549 			return EAI_MEMORY;
    550 		} else
    551 			return 0;
    552 #endif
    553 	case IFT_IEEE1394:
    554 		if (sdl->sdl_alen < sizeof(iha->iha_uid))
    555 			return EAI_FAMILY;
    556 		iha =
    557 		    (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl);
    558 		return hexname(iha->iha_uid, sizeof(iha->iha_uid),
    559 		    host, hostlen);
    560 	/*
    561 	 * The following have zero-length addresses.
    562 	 * IFT_ATM	(net/if_atmsubr.c)
    563 	 * IFT_FAITH	(net/if_faith.c)
    564 	 * IFT_GIF	(net/if_gif.c)
    565 	 * IFT_LOOP	(net/if_loop.c)
    566 	 * IFT_PPP	(net/if_ppp.c, net/if_spppsubr.c)
    567 	 * IFT_SLIP	(net/if_sl.c, net/if_strip.c)
    568 	 * IFT_STF	(net/if_stf.c)
    569 	 * IFT_L2VLAN	(net/if_vlan.c)
    570 	 * IFT_PROPVIRTUAL (net/if_bridge.h>
    571 	 */
    572 	/*
    573 	 * The following use IPv4 addresses as link-layer addresses:
    574 	 * IFT_OTHER	(net/if_gre.c)
    575 	 */
    576 	case IFT_ARCNET: /* default below is believed correct for all these. */
    577 	case IFT_ETHER:
    578 	case IFT_FDDI:
    579 	case IFT_HIPPI:
    580 	case IFT_ISO88025:
    581 	default:
    582 		return hexname((const uint8_t *)CLLADDR(sdl),
    583 		    (size_t)sdl->sdl_alen, host, hostlen);
    584 	}
    585 }
    586 
    587 static int
    588 hexname(const uint8_t *cp, size_t len, char *host, socklen_t hostlen)
    589 {
    590 	int n;
    591 	size_t i;
    592 	char *outp = host;
    593 
    594 	*outp = '\0';
    595 	for (i = 0; i < len; i++) {
    596 		n = snprintf(outp, hostlen, "%s%02x",
    597 		    i ? ":" : "", cp[i]);
    598 		if (n < 0 || (socklen_t) n >= hostlen) {
    599 			*host = '\0';
    600 			return EAI_MEMORY;
    601 		}
    602 		outp += n;
    603 		hostlen -= n;
    604 	}
    605 	return 0;
    606 }
    607