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getnameinfo.c revision 1.50 
      1 /*	$NetBSD: getnameinfo.c,v 1.50 2010/06/29 14:44:19 seanb 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 2010/06/29 14:44:19 seanb 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 <net/if.h>
     57 #include <net/if_dl.h>
     58 #include <net/if_ieee1394.h>
     59 #include <net/if_types.h>
     60 #include <netatalk/at.h>
     61 #include <netinet/in.h>
     62 #include <arpa/inet.h>
     63 #include <arpa/nameser.h>
     64 #include <assert.h>
     65 #include <limits.h>
     66 #include <netdb.h>
     67 #include <resolv.h>
     68 #include <stddef.h>
     69 #include <string.h>
     70 
     71 #include "servent.h"
     72 
     73 #ifdef __weak_alias
     74 __weak_alias(getnameinfo,_getnameinfo)
     75 #endif
     76 
     77 static const struct afd {
     78 	int		a_af;
     79 	socklen_t	a_addrlen;
     80 	socklen_t	a_socklen;
     81 	int		a_off;
     82 } afdl [] = {
     83 #ifdef INET6
     84 	{PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
     85 		offsetof(struct sockaddr_in6, sin6_addr)},
     86 #endif
     87 	{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
     88 		offsetof(struct sockaddr_in, sin_addr)},
     89 	{0, 0, 0, 0},
     90 };
     91 
     92 struct sockinet {
     93 	u_char	si_len;
     94 	u_char	si_family;
     95 	u_short	si_port;
     96 };
     97 
     98 static int getnameinfo_inet __P((const struct sockaddr *, socklen_t, char *,
     99     socklen_t, char *, socklen_t, int));
    100 #ifdef INET6
    101 static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *,
    102 				 socklen_t, int));
    103 static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t,
    104 				 int));
    105 #endif
    106 static int getnameinfo_atalk __P((const struct sockaddr *, socklen_t, char *,
    107     socklen_t, char *, socklen_t, int));
    108 
    109 static int getnameinfo_link __P((const struct sockaddr *, socklen_t, char *,
    110     socklen_t, char *, socklen_t, int));
    111 static int hexname __P((const u_int8_t *, size_t, char *, socklen_t));
    112 
    113 /*
    114  * Top-level getnameinfo() code.  Look at the address family, and pick an
    115  * appropriate function to call.
    116  */
    117 int
    118 getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
    119 	const struct sockaddr *sa;
    120 	socklen_t salen;
    121 	char *host, *serv;
    122 	socklen_t hostlen, 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 	default:
    138 		return EAI_FAMILY;
    139 	}
    140 }
    141 
    142 /*
    143  * getnameinfo_atalk():
    144  * Format an AppleTalk address into a printable format.
    145  */
    146 /* ARGSUSED */
    147 static int
    148 getnameinfo_atalk(const struct sockaddr *sa, socklen_t salen,
    149     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
    150     int flags)
    151 {
    152 	char numserv[8];
    153 	int n, m=0;
    154 
    155 	const struct sockaddr_at *sat =
    156 	    (const struct sockaddr_at *)(const void *)sa;
    157 
    158 	if (serv != NULL && servlen > 0) {
    159 		snprintf(numserv, sizeof(numserv), "%u", sat->sat_port);
    160 		if (strlen(numserv) + 1 > servlen)
    161 			return EAI_MEMORY;
    162 		strlcpy(serv, numserv, servlen);
    163 	}
    164 
    165         n = snprintf(host, hostlen, "%u.%u",
    166 	    ntohs(sat->sat_addr.s_net), sat->sat_addr.s_node);
    167 
    168 	if (n < 0 || (socklen_t)(m+n) >= hostlen)
    169 		goto errout;
    170 
    171 	m += n;
    172 
    173 	if (sat->sat_range.r_netrange.nr_phase) {
    174         	n = snprintf(host+m, hostlen-m, " phase %u",
    175 			sat->sat_range.r_netrange.nr_phase);
    176 
    177 		if (n < 0 || (socklen_t)(m+n) >= hostlen)
    178 			goto errout;
    179 
    180 		m += n;
    181 	}
    182 	if (sat->sat_range.r_netrange.nr_firstnet) {
    183         	n = snprintf(host+m, hostlen-m, " range %u - %u",
    184 			ntohs(sat->sat_range.r_netrange.nr_firstnet),
    185 			ntohs(sat->sat_range.r_netrange.nr_lastnet ));
    186 
    187 		if (n < 0 || (socklen_t)(m+n) >= hostlen)
    188 			goto errout;
    189 
    190 		m += n;
    191 	}
    192 
    193 	return 0;
    194 
    195 errout:
    196 	if (host && hostlen>0)
    197 		host[m] = '\0';	/* XXX ??? */
    198 
    199 	return EAI_MEMORY;
    200 }
    201 
    202 /*
    203  * getnameinfo_inet():
    204  * Format an IPv4 or IPv6 sockaddr into a printable string.
    205  */
    206 static int
    207 getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags)
    208 	const struct sockaddr *sa;
    209 	socklen_t salen;
    210 	char *host;
    211 	socklen_t hostlen;
    212 	char *serv;
    213 	socklen_t servlen;
    214 	int flags;
    215 {
    216 	const struct afd *afd;
    217 	struct servent *sp;
    218 	struct hostent *hp;
    219 	u_short port;
    220 	int family, i;
    221 	const char *addr;
    222 	u_int32_t v4a;
    223 	char numserv[512];
    224 	char numaddr[512];
    225 
    226 	/* sa is checked below */
    227 	/* host may be NULL */
    228 	/* serv may be NULL */
    229 
    230 	if (sa == NULL)
    231 		return EAI_FAIL;
    232 
    233 	family = sa->sa_family;
    234 	for (i = 0; afdl[i].a_af; i++)
    235 		if (afdl[i].a_af == family) {
    236 			afd = &afdl[i];
    237 			goto found;
    238 		}
    239 	return EAI_FAMILY;
    240 
    241  found:
    242 	if (salen != afd->a_socklen)
    243 		return EAI_FAIL;
    244 
    245 	/* network byte order */
    246 	port = ((const struct sockinet *)(const void *)sa)->si_port;
    247 	addr = (const char *)(const void *)sa + afd->a_off;
    248 
    249 	if (serv == NULL || servlen == 0) {
    250 		/*
    251 		 * do nothing in this case.
    252 		 * in case you are wondering if "&&" is more correct than
    253 		 * "||" here: rfc2553bis-03 says that serv == NULL OR
    254 		 * servlen == 0 means that the caller does not want the result.
    255 		 */
    256 	} else {
    257 		struct servent_data svd;
    258 		struct servent sv;
    259 
    260 		if (flags & NI_NUMERICSERV)
    261 			sp = NULL;
    262 		else {
    263 			(void)memset(&svd, 0, sizeof(svd));
    264 			sp = getservbyport_r(port,
    265 				(flags & NI_DGRAM) ? "udp" : "tcp", &sv, &svd);
    266 		}
    267 		if (sp) {
    268 			if (strlen(sp->s_name) + 1 > servlen) {
    269 				endservent_r(&svd);
    270 				return EAI_MEMORY;
    271 			}
    272 			strlcpy(serv, sp->s_name, servlen);
    273 			endservent_r(&svd);
    274 		} else {
    275 			snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
    276 			if (strlen(numserv) + 1 > servlen)
    277 				return EAI_MEMORY;
    278 			strlcpy(serv, numserv, servlen);
    279 		}
    280 	}
    281 
    282 	switch (sa->sa_family) {
    283 	case AF_INET:
    284 		v4a = (u_int32_t)
    285 		    ntohl(((const struct sockaddr_in *)
    286 		    (const void *)sa)->sin_addr.s_addr);
    287 		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
    288 			flags |= NI_NUMERICHOST;
    289 		v4a >>= IN_CLASSA_NSHIFT;
    290 		if (v4a == 0)
    291 			flags |= NI_NUMERICHOST;
    292 		break;
    293 #ifdef INET6
    294 	case AF_INET6:
    295 	    {
    296 		const struct sockaddr_in6 *sin6;
    297 		sin6 = (const struct sockaddr_in6 *)(const void *)sa;
    298 		switch (sin6->sin6_addr.s6_addr[0]) {
    299 		case 0x00:
    300 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
    301 				;
    302 			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
    303 				;
    304 			else
    305 				flags |= NI_NUMERICHOST;
    306 			break;
    307 		default:
    308 			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
    309 				flags |= NI_NUMERICHOST;
    310 			}
    311 			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
    312 				flags |= NI_NUMERICHOST;
    313 			break;
    314 		}
    315 	    }
    316 		break;
    317 #endif
    318 	}
    319 	if (host == NULL || hostlen == 0) {
    320 		/*
    321 		 * do nothing in this case.
    322 		 * in case you are wondering if "&&" is more correct than
    323 		 * "||" here: rfc2553bis-03 says that host == NULL or
    324 		 * hostlen == 0 means that the caller does not want the result.
    325 		 */
    326 	} else if (flags & NI_NUMERICHOST) {
    327 		size_t numaddrlen;
    328 
    329 		/* NUMERICHOST and NAMEREQD conflicts with each other */
    330 		if (flags & NI_NAMEREQD)
    331 			return EAI_NONAME;
    332 
    333 		switch(afd->a_af) {
    334 #ifdef INET6
    335 		case AF_INET6:
    336 		{
    337 			int error;
    338 
    339 			if ((error = ip6_parsenumeric(sa, addr, host,
    340 						      hostlen, flags)) != 0)
    341 				return(error);
    342 			break;
    343 		}
    344 #endif
    345 		default:
    346 			if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
    347 			    == NULL)
    348 				return EAI_SYSTEM;
    349 			numaddrlen = strlen(numaddr);
    350 			if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    351 				return EAI_MEMORY;
    352 			strlcpy(host, numaddr, hostlen);
    353 			break;
    354 		}
    355 	} else {
    356 		hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
    357 
    358 		if (hp) {
    359 #if 0
    360 			/*
    361 			 * commented out, since "for local host" is not
    362 			 * implemented here - see RFC2553 p30
    363 			 */
    364 			if (flags & NI_NOFQDN) {
    365 				char *p;
    366 				p = strchr(hp->h_name, '.');
    367 				if (p)
    368 					*p = '\0';
    369 			}
    370 #endif
    371 			if (strlen(hp->h_name) + 1 > hostlen) {
    372 				return EAI_MEMORY;
    373 			}
    374 			strlcpy(host, hp->h_name, hostlen);
    375 		} else {
    376 			if (flags & NI_NAMEREQD)
    377 				return EAI_NONAME;
    378 			switch(afd->a_af) {
    379 #ifdef INET6
    380 			case AF_INET6:
    381 			{
    382 				int error;
    383 
    384 				if ((error = ip6_parsenumeric(sa, addr, host,
    385 							      hostlen,
    386 							      flags)) != 0)
    387 					return(error);
    388 				break;
    389 			}
    390 #endif
    391 			default:
    392 				if (inet_ntop(afd->a_af, addr, host,
    393 				    hostlen) == NULL)
    394 					return EAI_SYSTEM;
    395 				break;
    396 			}
    397 		}
    398 	}
    399 	return(0);
    400 }
    401 
    402 #ifdef INET6
    403 static int
    404 ip6_parsenumeric(sa, addr, host, hostlen, flags)
    405 	const struct sockaddr *sa;
    406 	const char *addr;
    407 	char *host;
    408 	socklen_t hostlen;
    409 	int flags;
    410 {
    411 	size_t numaddrlen;
    412 	char numaddr[512];
    413 
    414 	_DIAGASSERT(sa != NULL);
    415 	_DIAGASSERT(addr != NULL);
    416 	_DIAGASSERT(host != NULL);
    417 
    418 	if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
    419 		return EAI_SYSTEM;
    420 
    421 	numaddrlen = strlen(numaddr);
    422 	if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    423 		return EAI_OVERFLOW;
    424 	strlcpy(host, numaddr, hostlen);
    425 
    426 	if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
    427 		char zonebuf[MAXHOSTNAMELEN];
    428 		int zonelen;
    429 
    430 		zonelen = ip6_sa2str(
    431 		    (const struct sockaddr_in6 *)(const void *)sa,
    432 		    zonebuf, sizeof(zonebuf), flags);
    433 		if (zonelen < 0)
    434 			return EAI_OVERFLOW;
    435 		if ((size_t) zonelen + 1 + numaddrlen + 1 > hostlen)
    436 			return EAI_OVERFLOW;
    437 		/* construct <numeric-addr><delim><zoneid> */
    438 		memcpy(host + numaddrlen + 1, zonebuf,
    439 		    (size_t)zonelen);
    440 		host[numaddrlen] = SCOPE_DELIMITER;
    441 		host[numaddrlen + 1 + zonelen] = '\0';
    442 	}
    443 
    444 	return 0;
    445 }
    446 
    447 /* ARGSUSED */
    448 static int
    449 ip6_sa2str(sa6, buf, bufsiz, flags)
    450 	const struct sockaddr_in6 *sa6;
    451 	char *buf;
    452 	size_t bufsiz;
    453 	int flags;
    454 {
    455 	unsigned int ifindex;
    456 	const struct in6_addr *a6;
    457 	int n;
    458 
    459 	_DIAGASSERT(sa6 != NULL);
    460 	_DIAGASSERT(buf != NULL);
    461 
    462 	ifindex = (unsigned int)sa6->sin6_scope_id;
    463 	a6 = &sa6->sin6_addr;
    464 
    465 #ifdef NI_NUMERICSCOPE
    466 	if ((flags & NI_NUMERICSCOPE) != 0) {
    467 		n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    468 		if (n < 0 || (size_t)n >= bufsiz)
    469 			return -1;
    470 		else
    471 			return n;
    472 	}
    473 #endif
    474 
    475 	/* if_indextoname() does not take buffer size.  not a good api... */
    476 	if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
    477 	    bufsiz >= IF_NAMESIZE) {
    478 		char *p = if_indextoname(ifindex, buf);
    479 		if (p) {
    480 			return(strlen(p));
    481 		}
    482 	}
    483 
    484 	/* last resort */
    485 	n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    486 	if (n < 0 || (size_t) n >= bufsiz)
    487 		return -1;
    488 	else
    489 		return n;
    490 }
    491 #endif /* INET6 */
    492 
    493 
    494 /*
    495  * getnameinfo_link():
    496  * Format a link-layer address into a printable format, paying attention to
    497  * the interface type.
    498  */
    499 /* ARGSUSED */
    500 static int
    501 getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
    502     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
    503     int flags)
    504 {
    505 	const struct sockaddr_dl *sdl =
    506 	    (const struct sockaddr_dl *)(const void *)sa;
    507 	const struct ieee1394_hwaddr *iha;
    508 	int n;
    509 
    510 	if (serv != NULL && servlen > 0)
    511 		*serv = '\0';
    512 
    513 	if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
    514 		n = snprintf(host, hostlen, "link#%u", sdl->sdl_index);
    515 		if (n < 0 || (socklen_t) n > hostlen) {
    516 			*host = '\0';
    517 			return EAI_MEMORY;
    518 		}
    519 		return 0;
    520 	}
    521 
    522 	switch (sdl->sdl_type) {
    523 #ifdef IFT_ECONET
    524 	case IFT_ECONET:
    525 		if (sdl->sdl_alen < 2)
    526 			return EAI_FAMILY;
    527 		if (CLLADDR(sdl)[1] == 0)
    528 			n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]);
    529 		else
    530 			n = snprintf(host, hostlen, "%u.%u",
    531 			    CLLADDR(sdl)[1], CLLADDR(sdl)[0]);
    532 		if (n < 0 || (socklen_t) n >= hostlen) {
    533 			*host = '\0';
    534 			return EAI_MEMORY;
    535 		} else
    536 			return 0;
    537 #endif
    538 	case IFT_IEEE1394:
    539 		if (sdl->sdl_alen < sizeof(iha->iha_uid))
    540 			return EAI_FAMILY;
    541 		iha =
    542 		    (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl);
    543 		return hexname(iha->iha_uid, sizeof(iha->iha_uid),
    544 		    host, hostlen);
    545 	/*
    546 	 * The following have zero-length addresses.
    547 	 * IFT_ATM	(net/if_atmsubr.c)
    548 	 * IFT_FAITH	(net/if_faith.c)
    549 	 * IFT_GIF	(net/if_gif.c)
    550 	 * IFT_LOOP	(net/if_loop.c)
    551 	 * IFT_PPP	(net/if_ppp.c, net/if_spppsubr.c)
    552 	 * IFT_SLIP	(net/if_sl.c, net/if_strip.c)
    553 	 * IFT_STF	(net/if_stf.c)
    554 	 * IFT_L2VLAN	(net/if_vlan.c)
    555 	 * IFT_PROPVIRTUAL (net/if_bridge.h>
    556 	 */
    557 	/*
    558 	 * The following use IPv4 addresses as link-layer addresses:
    559 	 * IFT_OTHER	(net/if_gre.c)
    560 	 */
    561 	case IFT_ARCNET: /* default below is believed correct for all these. */
    562 	case IFT_ETHER:
    563 	case IFT_FDDI:
    564 	case IFT_HIPPI:
    565 	case IFT_ISO88025:
    566 	default:
    567 		return hexname((const u_int8_t *)CLLADDR(sdl),
    568 		    (size_t)sdl->sdl_alen, host, hostlen);
    569 	}
    570 }
    571 
    572 static int
    573 hexname(cp, len, host, hostlen)
    574 	const u_int8_t *cp;
    575 	char *host;
    576 	size_t len;
    577 	socklen_t hostlen;
    578 {
    579 	int n;
    580 	size_t i;
    581 	char *outp = host;
    582 
    583 	*outp = '\0';
    584 	for (i = 0; i < len; i++) {
    585 		n = snprintf(outp, hostlen, "%s%02x",
    586 		    i ? ":" : "", cp[i]);
    587 		if (n < 0 || (socklen_t) n >= hostlen) {
    588 			*host = '\0';
    589 			return EAI_MEMORY;
    590 		}
    591 		outp += n;
    592 		hostlen -= n;
    593 	}
    594 	return 0;
    595 }
    596