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getnameinfo.c revision 1.32 
      1 /*	$NetBSD: getnameinfo.c,v 1.32 2001/10/06 13:59:41 bjh21 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) NI_WITHSCOPEID when called with global address,
     43  *   and sin6_scope_id filled
     44  */
     45 
     46 #include <sys/cdefs.h>
     47 #if defined(LIBC_SCCS) && !defined(lint)
     48 __RCSID("$NetBSD: getnameinfo.c,v 1.32 2001/10/06 13:59:41 bjh21 Exp $");
     49 #endif /* LIBC_SCCS and not lint */
     50 
     51 #include "namespace.h"
     52 #include <sys/types.h>
     53 #include <sys/socket.h>
     54 #include <net/if.h>
     55 #include <net/if_dl.h>
     56 #include <net/if_ieee1394.h>
     57 #include <net/if_types.h>
     58 #include <netinet/in.h>
     59 #include <arpa/inet.h>
     60 #include <arpa/nameser.h>
     61 #include <assert.h>
     62 #include <limits.h>
     63 #include <netdb.h>
     64 #include <resolv.h>
     65 #include <stddef.h>
     66 #include <string.h>
     67 
     68 #ifdef __weak_alias
     69 __weak_alias(getnameinfo,_getnameinfo)
     70 #endif
     71 
     72 #define SUCCESS 0
     73 #define ANY 0
     74 #define YES 1
     75 #define NO  0
     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},
     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     size_t, char *, size_t, int));
    100 #ifdef INET6
    101 static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *,
    102 				 size_t, int));
    103 static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t, int));
    104 #endif
    105 static int getnameinfo_link __P((const struct sockaddr *, socklen_t, char *,
    106     size_t, char *, size_t, int));
    107 static int hexname __P((const u_int8_t *, size_t, char *, size_t));
    108 
    109 /* 2553bis: use EAI_xx for getnameinfo */
    110 #define ENI_NOSOCKET 	EAI_FAIL		/*XXX*/
    111 #define ENI_NOSERVNAME	EAI_NONAME
    112 #define ENI_NOHOSTNAME	EAI_NONAME
    113 #define ENI_MEMORY	EAI_MEMORY
    114 #define ENI_SYSTEM	EAI_SYSTEM
    115 #define ENI_FAMILY	EAI_FAMILY
    116 #define ENI_SALEN	EAI_FAMILY
    117 
    118 /*
    119  * Top-level getnameinfo() code.  Look at the address family, and pick an
    120  * appropriate function to call.
    121  */
    122 int
    123 getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
    124 	const struct sockaddr *sa;
    125 	socklen_t salen;
    126 	char *host, *serv;
    127 	size_t hostlen, servlen;
    128 	int flags;
    129 {
    130 
    131 	switch (sa->sa_family) {
    132 	case AF_INET:
    133 	case AF_INET6:
    134 		return getnameinfo_inet(sa, salen, host, hostlen,
    135 		    serv, servlen, flags);
    136 	case AF_LINK:
    137 		return getnameinfo_link(sa, salen, host, hostlen,
    138 		    serv, servlen, flags);
    139 	default:
    140 		return EAI_FAMILY;
    141 	}
    142 }
    143 
    144 
    145 /*
    146  * getnameinfo_inet():
    147  * Format an IPv4 or IPv6 sockaddr into a printable string.
    148  */
    149 static int
    150 getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags)
    151 	const struct sockaddr *sa;
    152 	socklen_t salen;
    153 	char *host;
    154 	size_t hostlen;
    155 	char *serv;
    156 	size_t servlen;
    157 	int flags;
    158 {
    159 	const struct afd *afd;
    160 	struct servent *sp;
    161 	struct hostent *hp;
    162 	u_short port;
    163 	int family, i;
    164 	const char *addr;
    165 	u_int32_t v4a;
    166 	char numserv[512];
    167 	char numaddr[512];
    168 
    169 	/* sa is checked below */
    170 	/* host may be NULL */
    171 	/* serv may be NULL */
    172 
    173 	if (sa == NULL)
    174 		return ENI_NOSOCKET;
    175 
    176 #ifdef BSD4_4
    177 	if (sa->sa_len != salen)
    178 		return ENI_SALEN;
    179 #endif
    180 
    181 	family = sa->sa_family;
    182 	for (i = 0; afdl[i].a_af; i++)
    183 		if (afdl[i].a_af == family) {
    184 			afd = &afdl[i];
    185 			goto found;
    186 		}
    187 	return ENI_FAMILY;
    188 
    189  found:
    190 	if (salen != afd->a_socklen)
    191 		return ENI_SALEN;
    192 
    193 	/* network byte order */
    194 	port = ((const struct sockinet *)(const void *)sa)->si_port;
    195 	addr = (const char *)(const void *)sa + afd->a_off;
    196 
    197 	if (serv == NULL || servlen == 0) {
    198 		/*
    199 		 * do nothing in this case.
    200 		 * in case you are wondering if "&&" is more correct than
    201 		 * "||" here: RFC2553 says that serv == NULL OR servlen == 0
    202 		 * means that the caller does not want the result.
    203 		 */
    204 	} else {
    205 		if (flags & NI_NUMERICSERV)
    206 			sp = NULL;
    207 		else {
    208 			sp = getservbyport(port,
    209 				(flags & NI_DGRAM) ? "udp" : "tcp");
    210 		}
    211 		if (sp) {
    212 			if (strlen(sp->s_name) + 1 > servlen)
    213 				return ENI_MEMORY;
    214 			strcpy(serv, sp->s_name);
    215 		} else {
    216 			snprintf(numserv, sizeof(numserv), "%d", ntohs(port));
    217 			if (strlen(numserv) + 1 > servlen)
    218 				return ENI_MEMORY;
    219 			strcpy(serv, numserv);
    220 		}
    221 	}
    222 
    223 	switch (sa->sa_family) {
    224 	case AF_INET:
    225 		v4a = (u_int32_t)
    226 		    ntohl(((const struct sockaddr_in *)
    227 		    (const void *)sa)->sin_addr.s_addr);
    228 		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
    229 			flags |= NI_NUMERICHOST;
    230 		v4a >>= IN_CLASSA_NSHIFT;
    231 		if (v4a == 0)
    232 			flags |= NI_NUMERICHOST;
    233 		break;
    234 #ifdef INET6
    235 	case AF_INET6:
    236 	    {
    237 		const struct sockaddr_in6 *sin6;
    238 		sin6 = (const struct sockaddr_in6 *)(const void *)sa;
    239 		switch (sin6->sin6_addr.s6_addr[0]) {
    240 		case 0x00:
    241 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
    242 				;
    243 			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
    244 				;
    245 			else
    246 				flags |= NI_NUMERICHOST;
    247 			break;
    248 		default:
    249 			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
    250 				flags |= NI_NUMERICHOST;
    251 			}
    252 			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
    253 				flags |= NI_NUMERICHOST;
    254 			break;
    255 		}
    256 	    }
    257 		break;
    258 #endif
    259 	}
    260 	if (host == NULL || hostlen == 0) {
    261 		/*
    262 		 * do nothing in this case.
    263 		 * in case you are wondering if "&&" is more correct than
    264 		 * "||" here: RFC2553 says that host == NULL OR hostlen == 0
    265 		 * means that the caller does not want the result.
    266 		 */
    267 	} else if (flags & NI_NUMERICHOST) {
    268 		int numaddrlen;
    269 
    270 		/* NUMERICHOST and NAMEREQD conflicts with each other */
    271 		if (flags & NI_NAMEREQD)
    272 			return ENI_NOHOSTNAME;
    273 
    274 		switch(afd->a_af) {
    275 #ifdef INET6
    276 		case AF_INET6:
    277 		{
    278 			int error;
    279 
    280 			if ((error = ip6_parsenumeric(sa, addr, host,
    281 						      hostlen, flags)) != 0)
    282 				return(error);
    283 			break;
    284 		}
    285 #endif
    286 		default:
    287 			if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
    288 			    == NULL)
    289 				return ENI_SYSTEM;
    290 			numaddrlen = strlen(numaddr);
    291 			if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    292 				return ENI_MEMORY;
    293 			strcpy(host, numaddr);
    294 			break;
    295 		}
    296 	} else {
    297 		hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
    298 
    299 		if (hp) {
    300 #if 0
    301 			/*
    302 			 * commented out, since "for local host" is not
    303 			 * implemented here - see RFC2553 p30
    304 			 */
    305 			if (flags & NI_NOFQDN) {
    306 				char *p;
    307 				p = strchr(hp->h_name, '.');
    308 				if (p)
    309 					*p = '\0';
    310 			}
    311 #endif
    312 			if (strlen(hp->h_name) + 1 > hostlen) {
    313 				return ENI_MEMORY;
    314 			}
    315 			strcpy(host, hp->h_name);
    316 		} else {
    317 			if (flags & NI_NAMEREQD)
    318 				return ENI_NOHOSTNAME;
    319 			switch(afd->a_af) {
    320 #ifdef INET6
    321 			case AF_INET6:
    322 			{
    323 				int error;
    324 
    325 				if ((error = ip6_parsenumeric(sa, addr, host,
    326 							      hostlen,
    327 							      flags)) != 0)
    328 					return(error);
    329 				break;
    330 			}
    331 #endif
    332 			default:
    333 				if (inet_ntop(afd->a_af, addr, host,
    334 				    hostlen) == NULL)
    335 					return ENI_SYSTEM;
    336 				break;
    337 			}
    338 		}
    339 	}
    340 	return SUCCESS;
    341 }
    342 
    343 #ifdef INET6
    344 static int
    345 ip6_parsenumeric(sa, addr, host, hostlen, flags)
    346 	const struct sockaddr *sa;
    347 	const char *addr;
    348 	char *host;
    349 	size_t hostlen;
    350 	int flags;
    351 {
    352 	int numaddrlen;
    353 	char numaddr[512];
    354 
    355 	_DIAGASSERT(sa != NULL);
    356 	_DIAGASSERT(addr != NULL);
    357 	_DIAGASSERT(host != NULL);
    358 
    359 	if (inet_ntop(AF_INET6, addr, numaddr, sizeof(numaddr))
    360 	    == NULL)
    361 		return ENI_SYSTEM;
    362 
    363 	numaddrlen = strlen(numaddr);
    364 	if (numaddrlen + 1 > hostlen) /* don't forget terminator */
    365 		return ENI_MEMORY;
    366 	strcpy(host, numaddr);
    367 
    368 #ifdef NI_WITHSCOPEID
    369 	if (((const struct sockaddr_in6 *)(const void *)sa)->sin6_scope_id) {
    370 		if (flags & NI_WITHSCOPEID)
    371 		{
    372 			char scopebuf[MAXHOSTNAMELEN];
    373 			int scopelen;
    374 
    375 			scopelen = ip6_sa2str(
    376 			    (const struct sockaddr_in6 *)(const void *)sa,
    377 			    scopebuf, sizeof(scopebuf), 0);
    378 			if (scopelen < 0)
    379 				return ENI_MEMORY;
    380 			if (scopelen + 1 + numaddrlen + 1 > hostlen)
    381 				return ENI_MEMORY;
    382 			/*
    383 			 * construct <numeric-addr><delim><scopeid>
    384 			 */
    385 			memcpy(host + numaddrlen + 1, scopebuf,
    386 			    (size_t)scopelen);
    387 			host[numaddrlen] = SCOPE_DELIMITER;
    388 			host[numaddrlen + 1 + scopelen] = '\0';
    389 		}
    390 	}
    391 #endif /* NI_WITHSCOPEID */
    392 
    393 	return 0;
    394 }
    395 
    396 /* ARGSUSED */
    397 static int
    398 ip6_sa2str(sa6, buf, bufsiz, flags)
    399 	const struct sockaddr_in6 *sa6;
    400 	char *buf;
    401 	size_t bufsiz;
    402 	int flags;
    403 {
    404 	unsigned int ifindex;
    405 	const struct in6_addr *a6;
    406 	int n;
    407 
    408 	_DIAGASSERT(sa6 != NULL);
    409 	_DIAGASSERT(buf != NULL);
    410 
    411 	ifindex = (unsigned int)sa6->sin6_scope_id;
    412 	a6 = &sa6->sin6_addr;
    413 
    414 #ifdef NI_NUMERICSCOPE
    415 	if ((flags & NI_NUMERICSCOPE) != 0) {
    416 		n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    417 		if (n < 0 || n >= bufsiz)
    418 			return -1;
    419 		else
    420 			return n;
    421 	}
    422 #endif
    423 
    424 	/* if_indextoname() does not take buffer size.  not a good api... */
    425 	if ((IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) &&
    426 	    bufsiz >= IF_NAMESIZE) {
    427 		char *p = if_indextoname(ifindex, buf);
    428 		if (p) {
    429 			return(strlen(p));
    430 		}
    431 	}
    432 
    433 	/* last resort */
    434 	n = snprintf(buf, bufsiz, "%u", sa6->sin6_scope_id);
    435 	if (n < 0 || n >= bufsiz)
    436 		return -1;
    437 	else
    438 		return n;
    439 }
    440 #endif /* INET6 */
    441 
    442 
    443 /*
    444  * getnameinfo_link():
    445  * Format a link-layer address into a printable format, paying attention to
    446  * the interface type.
    447  */
    448 /* ARGSUSED */
    449 static int
    450 getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
    451     char *host, size_t hostlen, char *serv, size_t servlen, int flags)
    452 {
    453 	const struct sockaddr_dl *sdl =
    454 	    (const struct sockaddr_dl *)(const void *)sa;
    455 	const struct ieee1394_hwaddr *iha;
    456 	int n;
    457 
    458 	if (serv != NULL && servlen > 0)
    459 		*serv = '\0';
    460 
    461 	if (sdl->sdl_nlen == 0 && sdl->sdl_alen == 0 && sdl->sdl_slen == 0) {
    462 		n = snprintf(host, hostlen, "link#%d", sdl->sdl_index);
    463 		if (n > hostlen) {
    464 			*host = '\0';
    465 			return EAI_MEMORY;
    466 		}
    467 		return 0;
    468 	}
    469 
    470 	switch (sdl->sdl_type) {
    471 #ifdef IFT_ECONET
    472 	case IFT_ECONET:
    473 		if (sdl->sdl_alen < 2)
    474 			return EAI_FAMILY;
    475 		if (LLADDR(sdl)[1] == 0)
    476 			n = snprintf(host, hostlen, "%d", LLADDR(sdl)[0]);
    477 		else
    478 			n = snprintf(host, hostlen, "%d.%d",
    479 			    LLADDR(sdl)[1], LLADDR(sdl)[0]);
    480 		if (n >= hostlen) {
    481 			*host = '\0';
    482 			return EAI_MEMORY;
    483 		} else
    484 			return 0;
    485 #endif
    486 	case IFT_IEEE1394:
    487 		if (sdl->sdl_alen < sizeof(iha->iha_uid))
    488 			return EAI_FAMILY;
    489 		iha =
    490 		    (const struct ieee1394_hwaddr *)(const void *)LLADDR(sdl);
    491 		return hexname(iha->iha_uid, sizeof(iha->iha_uid),
    492 		    host, hostlen);
    493 	/*
    494 	 * The following have zero-length addresses.
    495 	 * IFT_ATM	(net/if_atmsubr.c)
    496 	 * IFT_FAITH	(net/if_faith.c)
    497 	 * IFT_GIF	(net/if_gif.c)
    498 	 * IFT_LOOP	(net/if_loop.c)
    499 	 * IFT_PPP	(net/if_ppp.c, net/if_spppsubr.c)
    500 	 * IFT_SLIP	(net/if_sl.c, net/if_strip.c)
    501 	 * IFT_STF	(net/if_stf.c)
    502 	 * IFT_L2VLAN	(net/if_vlan.c)
    503 	 * IFT_PROPVIRTUAL (net/if_bridge.h>
    504 	 */
    505 	/*
    506 	 * The following use IPv4 addresses as link-layer addresses:
    507 	 * IFT_OTHER	(net/if_gre.c)
    508 	 * IFT_OTHER	(netinet/ip_ipip.c)
    509 	 */
    510 	case IFT_ARCNET: /* default below is believed correct for all these. */
    511 	case IFT_ETHER:
    512 	case IFT_FDDI:
    513 	case IFT_HIPPI:
    514 	case IFT_ISO88025:
    515 	default:
    516 		return hexname((u_int8_t *)LLADDR(sdl), (size_t)sdl->sdl_alen,
    517 		    host, hostlen);
    518 	}
    519 }
    520 
    521 static int
    522 hexname(cp, len, host, hostlen)
    523 	const u_int8_t *cp;
    524 	char *host;
    525 	size_t len, hostlen;
    526 {
    527 	int i, n;
    528 	char *outp = host;
    529 
    530 	*outp = '\0';
    531 	for (i = 0; i < len; i++) {
    532 		n = snprintf(outp, hostlen, "%s%02x",
    533 		    i ? ":" : "", cp[i]);
    534 		if (n < 0 || n >= hostlen) {
    535 			*host = '\0';
    536 			return EAI_MEMORY;
    537 		}
    538 		outp += n;
    539 		hostlen -= n;
    540 	}
    541 	return 0;
    542 }
    543