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getnameinfo.c revision 1.52 
      1 /*	$NetBSD: getnameinfo.c,v 1.52 2012/03/20 17:44:18 matt 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 1.52 2012/03/20 17:44:18 matt 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(const struct sockaddr *, socklen_t, char *,
     99     socklen_t, char *, socklen_t, int);
    100 #ifdef INET6
    101 static int ip6_parsenumeric(const struct sockaddr *, const char *, char *,
    102 				 socklen_t, int);
    103 static int ip6_sa2str(const struct sockaddr_in6 *, char *, size_t, int);
    104 #endif
    105 static int getnameinfo_atalk(const struct sockaddr *, socklen_t, char *,
    106     socklen_t, char *, socklen_t, int);
    107 
    108 static int getnameinfo_link(const struct sockaddr *, socklen_t, char *,
    109     socklen_t, char *, socklen_t, int);
    110 static int hexname(const uint8_t *, size_t, char *, socklen_t);
    111 
    112 /*
    113  * Top-level getnameinfo() code.  Look at the address family, and pick an
    114  * appropriate function to call.
    115  */
    116 int
    117 getnameinfo(const struct sockaddr *sa, socklen_t salen,
    118 	char *host, socklen_t hostlen,
    119 	char *serv, socklen_t servlen,
    120 	int flags)
    121 {
    122 
    123 	switch (sa->sa_family) {
    124 	case AF_APPLETALK:
    125 		return getnameinfo_atalk(sa, salen, host, hostlen,
    126 		    serv, servlen, flags);
    127 	case AF_INET:
    128 	case AF_INET6:
    129 		return getnameinfo_inet(sa, salen, host, hostlen,
    130 		    serv, servlen, flags);
    131 	case AF_LINK:
    132 		return getnameinfo_link(sa, salen, host, hostlen,
    133 		    serv, servlen, flags);
    134 	default:
    135 		return EAI_FAMILY;
    136 	}
    137 }
    138 
    139 /*
    140  * getnameinfo_atalk():
    141  * Format an AppleTalk address into a printable format.
    142  */
    143 /* ARGSUSED */
    144 static int
    145 getnameinfo_atalk(const struct sockaddr *sa, socklen_t salen,
    146     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
    147     int flags)
    148 {
    149 	char numserv[8];
    150 	int n, m=0;
    151 
    152 	const struct sockaddr_at *sat =
    153 	    (const struct sockaddr_at *)(const void *)sa;
    154 
    155 	if (serv != NULL && servlen > 0) {
    156 		snprintf(numserv, sizeof(numserv), "%u", sat->sat_port);
    157 		if (strlen(numserv) + 1 > servlen)
    158 			return EAI_MEMORY;
    159 		strlcpy(serv, numserv, servlen);
    160 	}
    161 
    162         n = snprintf(host, hostlen, "%u.%u",
    163 	    ntohs(sat->sat_addr.s_net), sat->sat_addr.s_node);
    164 
    165 	if (n < 0 || (socklen_t)(m+n) >= hostlen)
    166 		goto errout;
    167 
    168 	m += n;
    169 
    170 	if (sat->sat_range.r_netrange.nr_phase) {
    171         	n = snprintf(host+m, hostlen-m, " phase %u",
    172 			sat->sat_range.r_netrange.nr_phase);
    173 
    174 		if (n < 0 || (socklen_t)(m+n) >= hostlen)
    175 			goto errout;
    176 
    177 		m += n;
    178 	}
    179 	if (sat->sat_range.r_netrange.nr_firstnet) {
    180         	n = snprintf(host+m, hostlen-m, " range %u - %u",
    181 			ntohs(sat->sat_range.r_netrange.nr_firstnet),
    182 			ntohs(sat->sat_range.r_netrange.nr_lastnet ));
    183 
    184 		if (n < 0 || (socklen_t)(m+n) >= hostlen)
    185 			goto errout;
    186 
    187 		m += n;
    188 	}
    189 
    190 	return 0;
    191 
    192 errout:
    193 	if (host && hostlen>0)
    194 		host[m] = '\0';	/* XXX ??? */
    195 
    196 	return EAI_MEMORY;
    197 }
    198 
    199 /*
    200  * getnameinfo_inet():
    201  * Format an IPv4 or IPv6 sockaddr into a printable string.
    202  */
    203 static int
    204 getnameinfo_inet(const struct sockaddr *sa, socklen_t salen,
    205 	char *host, socklen_t hostlen,
    206 	char *serv, socklen_t servlen,
    207 	int flags)
    208 {
    209 	const struct afd *afd;
    210 	struct servent *sp;
    211 	struct hostent *hp;
    212 	u_short port;
    213 	int family, i;
    214 	const char *addr;
    215 	uint32_t v4a;
    216 	char numserv[512];
    217 	char numaddr[512];
    218 
    219 	/* sa is checked below */
    220 	/* host may be NULL */
    221 	/* serv may be NULL */
    222 
    223 	if (sa == NULL)
    224 		return EAI_FAIL;
    225 
    226 	family = sa->sa_family;
    227 	for (i = 0; afdl[i].a_af; i++)
    228 		if (afdl[i].a_af == family) {
    229 			afd = &afdl[i];
    230 			goto found;
    231 		}
    232 	return EAI_FAMILY;
    233 
    234  found:
    235 	if (salen != afd->a_socklen)
    236 		return EAI_FAIL;
    237 
    238 	/* network byte order */
    239 	port = ((const struct sockinet *)(const void *)sa)->si_port;
    240 	addr = (const char *)(const void *)sa + afd->a_off;
    241 
    242 	if (serv == NULL || servlen == 0) {
    243 		/*
    244 		 * do nothing in this case.
    245 		 * in case you are wondering if "&&" is more correct than
    246 		 * "||" here: rfc2553bis-03 says that serv == NULL OR
    247 		 * servlen == 0 means that the caller does not want the result.
    248 		 */
    249 	} else {
    250 		struct servent_data svd;
    251 		struct servent sv;
    252 
    253 		if (flags & NI_NUMERICSERV)
    254 			sp = NULL;
    255 		else {
    256 			(void)memset(&svd, 0, sizeof(svd));
    257 			sp = getservbyport_r(port,
    258 				(flags & NI_DGRAM) ? "udp" : "tcp", &sv, &svd);
    259 		}
    260 		if (sp) {
    261 			if (strlen(sp->s_name) + 1 > servlen) {
    262 				endservent_r(&svd);
    263 				return EAI_MEMORY;
    264 			}
    265 			strlcpy(serv, sp->s_name, servlen);
    266 			endservent_r(&svd);
    267 		} else {
    268 			snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
    269 			if (strlen(numserv) + 1 > servlen)
    270 				return EAI_MEMORY;
    271 			strlcpy(serv, numserv, servlen);
    272 		}
    273 	}
    274 
    275 	switch (sa->sa_family) {
    276 	case AF_INET:
    277 		v4a = (uint32_t)
    278 		    ntohl(((const struct sockaddr_in *)
    279 		    (const void *)sa)->sin_addr.s_addr);
    280 		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
    281 			flags |= NI_NUMERICHOST;
    282 		v4a >>= IN_CLASSA_NSHIFT;
    283 		if (v4a == 0)
    284 			flags |= NI_NUMERICHOST;
    285 		break;
    286 #ifdef INET6
    287 	case AF_INET6:
    288 	    {
    289 		const struct sockaddr_in6 *sin6;
    290 		sin6 = (const struct sockaddr_in6 *)(const void *)sa;
    291 		switch (sin6->sin6_addr.s6_addr[0]) {
    292 		case 0x00:
    293 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
    294 				;
    295 			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
    296 				;
    297 			else
    298 				flags |= NI_NUMERICHOST;
    299 			break;
    300 		default:
    301 			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
    302 				flags |= NI_NUMERICHOST;
    303 			}
    304 			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
    305 				flags |= NI_NUMERICHOST;
    306 			break;
    307 		}
    308 	    }
    309 		break;
    310 #endif
    311 	}
    312 	if (host == NULL || hostlen == 0) {
    313 		/*
    314 		 * do nothing in this case.
    315 		 * in case you are wondering if "&&" is more correct than
    316 		 * "||" here: rfc2553bis-03 says that host == NULL or
    317 		 * hostlen == 0 means that the caller does not want the result.
    318 		 */
    319 	} else if (flags & NI_NUMERICHOST) {
    320 		size_t numaddrlen;
    321 
    322 		/* NUMERICHOST and NAMEREQD conflicts with each other */
    323 		if (flags & NI_NAMEREQD)
    324 			return EAI_NONAME;
    325 
    326 		switch(afd->a_af) {
    327 #ifdef INET6
    328 		case AF_INET6:
    329 		{
    330 			int error;
    331 
    332 			if ((error = ip6_parsenumeric(sa, addr, host,
    333 						      hostlen, flags)) != 0)
    334 				return(error);
    335 			break;
    336 		}
    337 #endif
    338 		default:
    339 			if (inet_ntop(afd->a_af, addr, numaddr,
    340 			    (socklen_t)sizeof(numaddr)) == NULL)
    341 				return EAI_SYSTEM;
    342 			numaddrlen = strlen(numaddr);
    343 			if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    344 				return EAI_MEMORY;
    345 			strlcpy(host, numaddr, hostlen);
    346 			break;
    347 		}
    348 	} else {
    349 		hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
    350 
    351 		if (hp) {
    352 #if 0
    353 			/*
    354 			 * commented out, since "for local host" is not
    355 			 * implemented here - see RFC2553 p30
    356 			 */
    357 			if (flags & NI_NOFQDN) {
    358 				char *p;
    359 				p = strchr(hp->h_name, '.');
    360 				if (p)
    361 					*p = '\0';
    362 			}
    363 #endif
    364 			if (strlen(hp->h_name) + 1 > hostlen) {
    365 				return EAI_MEMORY;
    366 			}
    367 			strlcpy(host, hp->h_name, hostlen);
    368 		} else {
    369 			if (flags & NI_NAMEREQD)
    370 				return EAI_NONAME;
    371 			switch(afd->a_af) {
    372 #ifdef INET6
    373 			case AF_INET6:
    374 			{
    375 				int error;
    376 
    377 				if ((error = ip6_parsenumeric(sa, addr, host,
    378 							      hostlen,
    379 							      flags)) != 0)
    380 					return(error);
    381 				break;
    382 			}
    383 #endif
    384 			default:
    385 				if (inet_ntop(afd->a_af, addr, host,
    386 				    hostlen) == NULL)
    387 					return EAI_SYSTEM;
    388 				break;
    389 			}
    390 		}
    391 	}
    392 	return(0);
    393 }
    394 
    395 #ifdef INET6
    396 static int
    397 ip6_parsenumeric(const struct sockaddr *sa, const char *addr, char *host,
    398 	socklen_t hostlen, int flags)
    399 {
    400 	size_t numaddrlen;
    401 	char numaddr[512];
    402 
    403 	_DIAGASSERT(sa != NULL);
    404 	_DIAGASSERT(addr != NULL);
    405 	_DIAGASSERT(host != NULL);
    406 
    407 	if (inet_ntop(AF_INET6, addr, numaddr, (socklen_t)sizeof(numaddr))
    408 	    == NULL)
    409 		return EAI_SYSTEM;
    410 
    411 	numaddrlen = strlen(numaddr);
    412 	if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    413 		return EAI_OVERFLOW;
    414 	strlcpy(host, numaddr, hostlen);
    415 
    416 	if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
    417 		char zonebuf[MAXHOSTNAMELEN];
    418 		int zonelen;
    419 
    420 		zonelen = ip6_sa2str(
    421 		    (const struct sockaddr_in6 *)(const void *)sa,
    422 		    zonebuf, sizeof(zonebuf), flags);
    423 		if (zonelen < 0)
    424 			return EAI_OVERFLOW;
    425 		if ((size_t) zonelen + 1 + numaddrlen + 1 > hostlen)
    426 			return EAI_OVERFLOW;
    427 		/* construct <numeric-addr><delim><zoneid> */
    428 		memcpy(host + numaddrlen + 1, zonebuf,
    429 		    (size_t)zonelen);
    430 		host[numaddrlen] = SCOPE_DELIMITER;
    431 		host[numaddrlen + 1 + zonelen] = '\0';
    432 	}
    433 
    434 	return 0;
    435 }
    436 
    437 /* ARGSUSED */
    438 static int
    439 ip6_sa2str(const struct sockaddr_in6 *sa6, char *buf, size_t bufsiz, int flags)
    440 {
    441 	unsigned int ifindex;
    442 	const struct in6_addr *a6;
    443 	int n;
    444 
    445 	_DIAGASSERT(sa6 != NULL);
    446 	_DIAGASSERT(buf != NULL);
    447 
    448 	ifindex = (unsigned int)sa6->sin6_scope_id;
    449 	a6 = &sa6->sin6_addr;
    450 
    451 #ifdef NI_NUMERICSCOPE
    452 	if ((flags & NI_NUMERICSCOPE) != 0) {
    453 		n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    454 		if (n < 0 || (size_t)n >= bufsiz)
    455 			return -1;
    456 		else
    457 			return n;
    458 	}
    459 #endif
    460 
    461 	/* if_indextoname() does not take buffer size.  not a good api... */
    462 	if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
    463 	    bufsiz >= IF_NAMESIZE) {
    464 		char *p = if_indextoname(ifindex, buf);
    465 		if (p) {
    466 			return (int)strlen(p);
    467 		}
    468 	}
    469 
    470 	/* last resort */
    471 	n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    472 	if (n < 0 || (size_t) n >= bufsiz)
    473 		return -1;
    474 	else
    475 		return n;
    476 }
    477 #endif /* INET6 */
    478 
    479 
    480 /*
    481  * getnameinfo_link():
    482  * Format a link-layer address into a printable format, paying attention to
    483  * the interface type.
    484  */
    485 /* ARGSUSED */
    486 static int
    487 getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
    488     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
    489     int flags)
    490 {
    491 	const struct sockaddr_dl *sdl =
    492 	    (const struct sockaddr_dl *)(const void *)sa;
    493 	const struct ieee1394_hwaddr *iha;
    494 	int n;
    495 
    496 	if (serv != NULL && servlen > 0)
    497 		*serv = '\0';
    498 
    499 	if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
    500 		n = snprintf(host, hostlen, "link#%u", sdl->sdl_index);
    501 		if (n < 0 || (socklen_t) n > hostlen) {
    502 			*host = '\0';
    503 			return EAI_MEMORY;
    504 		}
    505 		return 0;
    506 	}
    507 
    508 	switch (sdl->sdl_type) {
    509 #ifdef IFT_ECONET
    510 	case IFT_ECONET:
    511 		if (sdl->sdl_alen < 2)
    512 			return EAI_FAMILY;
    513 		if (CLLADDR(sdl)[1] == 0)
    514 			n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]);
    515 		else
    516 			n = snprintf(host, hostlen, "%u.%u",
    517 			    CLLADDR(sdl)[1], CLLADDR(sdl)[0]);
    518 		if (n < 0 || (socklen_t) n >= hostlen) {
    519 			*host = '\0';
    520 			return EAI_MEMORY;
    521 		} else
    522 			return 0;
    523 #endif
    524 	case IFT_IEEE1394:
    525 		if (sdl->sdl_alen < sizeof(iha->iha_uid))
    526 			return EAI_FAMILY;
    527 		iha =
    528 		    (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl);
    529 		return hexname(iha->iha_uid, sizeof(iha->iha_uid),
    530 		    host, hostlen);
    531 	/*
    532 	 * The following have zero-length addresses.
    533 	 * IFT_ATM	(net/if_atmsubr.c)
    534 	 * IFT_FAITH	(net/if_faith.c)
    535 	 * IFT_GIF	(net/if_gif.c)
    536 	 * IFT_LOOP	(net/if_loop.c)
    537 	 * IFT_PPP	(net/if_ppp.c, net/if_spppsubr.c)
    538 	 * IFT_SLIP	(net/if_sl.c, net/if_strip.c)
    539 	 * IFT_STF	(net/if_stf.c)
    540 	 * IFT_L2VLAN	(net/if_vlan.c)
    541 	 * IFT_PROPVIRTUAL (net/if_bridge.h>
    542 	 */
    543 	/*
    544 	 * The following use IPv4 addresses as link-layer addresses:
    545 	 * IFT_OTHER	(net/if_gre.c)
    546 	 */
    547 	case IFT_ARCNET: /* default below is believed correct for all these. */
    548 	case IFT_ETHER:
    549 	case IFT_FDDI:
    550 	case IFT_HIPPI:
    551 	case IFT_ISO88025:
    552 	default:
    553 		return hexname((const uint8_t *)CLLADDR(sdl),
    554 		    (size_t)sdl->sdl_alen, host, hostlen);
    555 	}
    556 }
    557 
    558 static int
    559 hexname(const uint8_t *cp, size_t len, char *host, socklen_t hostlen)
    560 {
    561 	int n;
    562 	size_t i;
    563 	char *outp = host;
    564 
    565 	*outp = '\0';
    566 	for (i = 0; i < len; i++) {
    567 		n = snprintf(outp, hostlen, "%s%02x",
    568 		    i ? ":" : "", cp[i]);
    569 		if (n < 0 || (socklen_t) n >= hostlen) {
    570 			*host = '\0';
    571 			return EAI_MEMORY;
    572 		}
    573 		outp += n;
    574 		hostlen -= n;
    575 	}
    576 	return 0;
    577 }
    578