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getnameinfo.c revision 1.45.24.1 
      1 /*	$NetBSD: getnameinfo.c,v 1.45.24.1 2013/12/18 20:23:36 bouyer 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 1.45.24.1 2013/12/18 20:23:36 bouyer 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 <netinet/in.h>
     61 #include <arpa/inet.h>
     62 #include <arpa/nameser.h>
     63 #include <assert.h>
     64 #include <limits.h>
     65 #include <netdb.h>
     66 #include <resolv.h>
     67 #include <stddef.h>
     68 #include <string.h>
     69 
     70 #include "servent.h"
     71 #include "hostent.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_link __P((const struct sockaddr *, socklen_t, char *,
    107     socklen_t, char *, socklen_t, int));
    108 static int hexname __P((const u_int8_t *, size_t, char *, socklen_t));
    109 
    110 /*
    111  * Top-level getnameinfo() code.  Look at the address family, and pick an
    112  * appropriate function to call.
    113  */
    114 int
    115 getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
    116 	const struct sockaddr *sa;
    117 	socklen_t salen;
    118 	char *host, *serv;
    119 	socklen_t hostlen, servlen;
    120 	int flags;
    121 {
    122 
    123 	switch (sa->sa_family) {
    124 	case AF_INET:
    125 	case AF_INET6:
    126 		return getnameinfo_inet(sa, salen, host, hostlen,
    127 		    serv, servlen, flags);
    128 	case AF_LINK:
    129 		return getnameinfo_link(sa, salen, host, hostlen,
    130 		    serv, servlen, flags);
    131 	default:
    132 		return EAI_FAMILY;
    133 	}
    134 }
    135 
    136 
    137 /*
    138  * getnameinfo_inet():
    139  * Format an IPv4 or IPv6 sockaddr into a printable string.
    140  */
    141 static int
    142 getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags)
    143 	const struct sockaddr *sa;
    144 	socklen_t salen;
    145 	char *host;
    146 	socklen_t hostlen;
    147 	char *serv;
    148 	socklen_t servlen;
    149 	int flags;
    150 {
    151 	const struct afd *afd;
    152 	struct servent *sp;
    153 	struct hostent *hp;
    154 	u_short port;
    155 	int family, i;
    156 	const char *addr;
    157 	u_int32_t v4a;
    158 	char numserv[512];
    159 	char numaddr[512];
    160 
    161 	/* sa is checked below */
    162 	/* host may be NULL */
    163 	/* serv may be NULL */
    164 
    165 	if (sa == NULL)
    166 		return EAI_FAIL;
    167 
    168 #ifdef BSD4_4
    169 	if (sa->sa_len != salen)
    170 		return EAI_FAIL;
    171 #endif
    172 
    173 	family = sa->sa_family;
    174 	for (i = 0; afdl[i].a_af; i++)
    175 		if (afdl[i].a_af == family) {
    176 			afd = &afdl[i];
    177 			goto found;
    178 		}
    179 	return EAI_FAMILY;
    180 
    181  found:
    182 	if (salen != afd->a_socklen)
    183 		return EAI_FAIL;
    184 
    185 	/* network byte order */
    186 	port = ((const struct sockinet *)(const void *)sa)->si_port;
    187 	addr = (const char *)(const void *)sa + afd->a_off;
    188 
    189 	if (serv == NULL || servlen == 0) {
    190 		/*
    191 		 * do nothing in this case.
    192 		 * in case you are wondering if "&&" is more correct than
    193 		 * "||" here: rfc2553bis-03 says that serv == NULL OR
    194 		 * servlen == 0 means that the caller does not want the result.
    195 		 */
    196 	} else {
    197 		if (flags & NI_NUMERICSERV)
    198 			sp = NULL;
    199 		else {
    200 			struct servent_data svd;
    201 			struct servent sv;
    202 
    203 			(void)memset(&svd, 0, sizeof(svd));
    204 			sp = getservbyport_r(port,
    205 				(flags & NI_DGRAM) ? "udp" : "tcp", &sv, &svd);
    206 			endservent_r(&svd);
    207 		}
    208 		if (sp) {
    209 			if (strlen(sp->s_name) + 1 > servlen)
    210 				return EAI_MEMORY;
    211 			strlcpy(serv, sp->s_name, servlen);
    212 		} else {
    213 			snprintf(numserv, sizeof(numserv), "%u", ntohs(port));
    214 			if (strlen(numserv) + 1 > servlen)
    215 				return EAI_MEMORY;
    216 			strlcpy(serv, numserv, servlen);
    217 		}
    218 	}
    219 
    220 	switch (sa->sa_family) {
    221 	case AF_INET:
    222 		v4a = (u_int32_t)
    223 		    ntohl(((const struct sockaddr_in *)
    224 		    (const void *)sa)->sin_addr.s_addr);
    225 		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
    226 			flags |= NI_NUMERICHOST;
    227 		v4a >>= IN_CLASSA_NSHIFT;
    228 		if (v4a == 0)
    229 			flags |= NI_NUMERICHOST;
    230 		break;
    231 #ifdef INET6
    232 	case AF_INET6:
    233 	    {
    234 		const struct sockaddr_in6 *sin6;
    235 		sin6 = (const struct sockaddr_in6 *)(const void *)sa;
    236 		switch (sin6->sin6_addr.s6_addr[0]) {
    237 		case 0x00:
    238 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
    239 				;
    240 			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
    241 				;
    242 			else
    243 				flags |= NI_NUMERICHOST;
    244 			break;
    245 		default:
    246 			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
    247 				flags |= NI_NUMERICHOST;
    248 			}
    249 			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
    250 				flags |= NI_NUMERICHOST;
    251 			break;
    252 		}
    253 	    }
    254 		break;
    255 #endif
    256 	}
    257 	if (host == NULL || hostlen == 0) {
    258 		/*
    259 		 * do nothing in this case.
    260 		 * in case you are wondering if "&&" is more correct than
    261 		 * "||" here: rfc2553bis-03 says that host == NULL or
    262 		 * hostlen == 0 means that the caller does not want the result.
    263 		 */
    264 	} else if (flags & NI_NUMERICHOST) {
    265 		size_t numaddrlen;
    266 
    267 		/* NUMERICHOST and NAMEREQD conflicts with each other */
    268 		if (flags & NI_NAMEREQD)
    269 			return EAI_NONAME;
    270 
    271 		switch(afd->a_af) {
    272 #ifdef INET6
    273 		case AF_INET6:
    274 		{
    275 			int error;
    276 
    277 			if ((error = ip6_parsenumeric(sa, addr, host,
    278 						      hostlen, flags)) != 0)
    279 				return(error);
    280 			break;
    281 		}
    282 #endif
    283 		default:
    284 			if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
    285 			    == NULL)
    286 				return EAI_SYSTEM;
    287 			numaddrlen = strlen(numaddr);
    288 			if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    289 				return EAI_MEMORY;
    290 			strlcpy(host, numaddr, hostlen);
    291 			break;
    292 		}
    293 	} else {
    294 		struct hostent hent;
    295 		char hbuf[4096];
    296 		int he;
    297 		hp = gethostbyaddr_r(addr, afd->a_addrlen, afd->a_af, &hent,
    298 		    hbuf, sizeof(hbuf), &he);
    299 
    300 		if (hp) {
    301 #if 0
    302 			/*
    303 			 * commented out, since "for local host" is not
    304 			 * implemented here - see RFC2553 p30
    305 			 */
    306 			if (flags & NI_NOFQDN) {
    307 				char *p;
    308 				p = strchr(hp->h_name, '.');
    309 				if (p)
    310 					*p = '\0';
    311 			}
    312 #endif
    313 			if (strlen(hp->h_name) + 1 > hostlen) {
    314 				return EAI_MEMORY;
    315 			}
    316 			strlcpy(host, hp->h_name, hostlen);
    317 		} else {
    318 			if (flags & NI_NAMEREQD)
    319 				return EAI_NONAME;
    320 			switch(afd->a_af) {
    321 #ifdef INET6
    322 			case AF_INET6:
    323 			{
    324 				int error;
    325 
    326 				if ((error = ip6_parsenumeric(sa, addr, host,
    327 							      hostlen,
    328 							      flags)) != 0)
    329 					return(error);
    330 				break;
    331 			}
    332 #endif
    333 			default:
    334 				if (inet_ntop(afd->a_af, addr, host,
    335 				    hostlen) == NULL)
    336 					return EAI_SYSTEM;
    337 				break;
    338 			}
    339 		}
    340 	}
    341 	return(0);
    342 }
    343 
    344 #ifdef INET6
    345 static int
    346 ip6_parsenumeric(sa, addr, host, hostlen, flags)
    347 	const struct sockaddr *sa;
    348 	const char *addr;
    349 	char *host;
    350 	socklen_t hostlen;
    351 	int flags;
    352 {
    353 	size_t numaddrlen;
    354 	char numaddr[512];
    355 
    356 	_DIAGASSERT(sa != NULL);
    357 	_DIAGASSERT(addr != NULL);
    358 	_DIAGASSERT(host != NULL);
    359 
    360 	if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr)) == NULL)
    361 		return EAI_SYSTEM;
    362 
    363 	numaddrlen = strlen(numaddr);
    364 	if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    365 		return EAI_OVERFLOW;
    366 	strlcpy(host, numaddr, hostlen);
    367 
    368 	if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
    369 		char zonebuf[MAXHOSTNAMELEN];
    370 		int zonelen;
    371 
    372 		zonelen = ip6_sa2str(
    373 		    (const struct sockaddr_in6 *)(const void *)sa,
    374 		    zonebuf, sizeof(zonebuf), flags);
    375 		if (zonelen < 0)
    376 			return EAI_OVERFLOW;
    377 		if ((size_t) zonelen + 1 + numaddrlen + 1 > hostlen)
    378 			return EAI_OVERFLOW;
    379 		/* construct <numeric-addr><delim><zoneid> */
    380 		memcpy(host + numaddrlen + 1, zonebuf,
    381 		    (size_t)zonelen);
    382 		host[numaddrlen] = SCOPE_DELIMITER;
    383 		host[numaddrlen + 1 + zonelen] = '\0';
    384 	}
    385 
    386 	return 0;
    387 }
    388 
    389 /* ARGSUSED */
    390 static int
    391 ip6_sa2str(sa6, buf, bufsiz, flags)
    392 	const struct sockaddr_in6 *sa6;
    393 	char *buf;
    394 	size_t bufsiz;
    395 	int flags;
    396 {
    397 	unsigned int ifindex;
    398 	const struct in6_addr *a6;
    399 	int n;
    400 
    401 	_DIAGASSERT(sa6 != NULL);
    402 	_DIAGASSERT(buf != NULL);
    403 
    404 	ifindex = (unsigned int)sa6->sin6_scope_id;
    405 	a6 = &sa6->sin6_addr;
    406 
    407 #ifdef NI_NUMERICSCOPE
    408 	if ((flags & NI_NUMERICSCOPE) != 0) {
    409 		n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    410 		if (n < 0 || n >= bufsiz)
    411 			return -1;
    412 		else
    413 			return n;
    414 	}
    415 #endif
    416 
    417 	/* if_indextoname() does not take buffer size.  not a good api... */
    418 	if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
    419 	    bufsiz >= IF_NAMESIZE) {
    420 		char *p = if_indextoname(ifindex, buf);
    421 		if (p) {
    422 			return(strlen(p));
    423 		}
    424 	}
    425 
    426 	/* last resort */
    427 	n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    428 	if (n < 0 || (size_t) n >= bufsiz)
    429 		return -1;
    430 	else
    431 		return n;
    432 }
    433 #endif /* INET6 */
    434 
    435 
    436 /*
    437  * getnameinfo_link():
    438  * Format a link-layer address into a printable format, paying attention to
    439  * the interface type.
    440  */
    441 /* ARGSUSED */
    442 static int
    443 getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
    444     char *host, socklen_t hostlen, char *serv, socklen_t servlen,
    445     int flags)
    446 {
    447 	const struct sockaddr_dl *sdl =
    448 	    (const struct sockaddr_dl *)(const void *)sa;
    449 	const struct ieee1394_hwaddr *iha;
    450 	int n;
    451 
    452 	if (serv != NULL && servlen > 0)
    453 		*serv = '\0';
    454 
    455 	if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
    456 		n = snprintf(host, hostlen, "link#%u", sdl->sdl_index);
    457 		if (n < 0 || (socklen_t) n > hostlen) {
    458 			*host = '\0';
    459 			return EAI_MEMORY;
    460 		}
    461 		return 0;
    462 	}
    463 
    464 	switch (sdl->sdl_type) {
    465 #ifdef IFT_ECONET
    466 	case IFT_ECONET:
    467 		if (sdl->sdl_alen < 2)
    468 			return EAI_FAMILY;
    469 		if (CLLADDR(sdl)[1] == 0)
    470 			n = snprintf(host, hostlen, "%u", CLLADDR(sdl)[0]);
    471 		else
    472 			n = snprintf(host, hostlen, "%u.%u",
    473 			    CLLADDR(sdl)[1], CLLADDR(sdl)[0]);
    474 		if (n < 0 || (socklen_t) n >= hostlen) {
    475 			*host = '\0';
    476 			return EAI_MEMORY;
    477 		} else
    478 			return 0;
    479 #endif
    480 	case IFT_IEEE1394:
    481 		if (sdl->sdl_alen < sizeof(iha->iha_uid))
    482 			return EAI_FAMILY;
    483 		iha =
    484 		    (const struct ieee1394_hwaddr *)(const void *)CLLADDR(sdl);
    485 		return hexname(iha->iha_uid, sizeof(iha->iha_uid),
    486 		    host, hostlen);
    487 	/*
    488 	 * The following have zero-length addresses.
    489 	 * IFT_ATM	(net/if_atmsubr.c)
    490 	 * IFT_FAITH	(net/if_faith.c)
    491 	 * IFT_GIF	(net/if_gif.c)
    492 	 * IFT_LOOP	(net/if_loop.c)
    493 	 * IFT_PPP	(net/if_ppp.c, net/if_spppsubr.c)
    494 	 * IFT_SLIP	(net/if_sl.c, net/if_strip.c)
    495 	 * IFT_STF	(net/if_stf.c)
    496 	 * IFT_L2VLAN	(net/if_vlan.c)
    497 	 * IFT_PROPVIRTUAL (net/if_bridge.h>
    498 	 */
    499 	/*
    500 	 * The following use IPv4 addresses as link-layer addresses:
    501 	 * IFT_OTHER	(net/if_gre.c)
    502 	 */
    503 	case IFT_ARCNET: /* default below is believed correct for all these. */
    504 	case IFT_ETHER:
    505 	case IFT_FDDI:
    506 	case IFT_HIPPI:
    507 	case IFT_ISO88025:
    508 	default:
    509 		return hexname((const u_int8_t *)CLLADDR(sdl),
    510 		    (size_t)sdl->sdl_alen, host, hostlen);
    511 	}
    512 }
    513 
    514 static int
    515 hexname(cp, len, host, hostlen)
    516 	const u_int8_t *cp;
    517 	char *host;
    518 	size_t len;
    519 	socklen_t hostlen;
    520 {
    521 	int n;
    522 	size_t i;
    523 	char *outp = host;
    524 
    525 	*outp = '\0';
    526 	for (i = 0; i < len; i++) {
    527 		n = snprintf(outp, hostlen, "%s%02x",
    528 		    i ? ":" : "", cp[i]);
    529 		if (n < 0 || (socklen_t) n >= hostlen) {
    530 			*host = '\0';
    531 			return EAI_MEMORY;
    532 		}
    533 		outp += n;
    534 		hostlen -= n;
    535 	}
    536 	return 0;
    537 }
    538