xref: /freebsd/lib/libc/inet/inet_ntop.c (revision 71099ec5097cff9b4a566e5474b7f214bd539e8a)
165e96449SHajimu UMEMOTO /*
265e96449SHajimu UMEMOTO  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
365e96449SHajimu UMEMOTO  * Copyright (c) 1996-1999 by Internet Software Consortium.
465e96449SHajimu UMEMOTO  *
565e96449SHajimu UMEMOTO  * Permission to use, copy, modify, and distribute this software for any
665e96449SHajimu UMEMOTO  * purpose with or without fee is hereby granted, provided that the above
765e96449SHajimu UMEMOTO  * copyright notice and this permission notice appear in all copies.
865e96449SHajimu UMEMOTO  *
965e96449SHajimu UMEMOTO  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
1065e96449SHajimu UMEMOTO  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
1165e96449SHajimu UMEMOTO  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
1265e96449SHajimu UMEMOTO  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
1365e96449SHajimu UMEMOTO  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
1465e96449SHajimu UMEMOTO  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
1565e96449SHajimu UMEMOTO  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
1665e96449SHajimu UMEMOTO  */
1765e96449SHajimu UMEMOTO 
1865e96449SHajimu UMEMOTO #if defined(LIBC_SCCS) && !defined(lint)
19dde4a85dSHajimu UMEMOTO static const char rcsid[] = "$Id: inet_ntop.c,v 1.3.18.2 2005/11/03 23:02:22 marka Exp $";
2065e96449SHajimu UMEMOTO #endif /* LIBC_SCCS and not lint */
21ab96eeabSHajimu UMEMOTO #include <sys/cdefs.h>
22ab96eeabSHajimu UMEMOTO __FBSDID("$FreeBSD$");
2365e96449SHajimu UMEMOTO 
2465e96449SHajimu UMEMOTO #include "port_before.h"
2565e96449SHajimu UMEMOTO 
2665e96449SHajimu UMEMOTO #include <sys/param.h>
2765e96449SHajimu UMEMOTO #include <sys/types.h>
2865e96449SHajimu UMEMOTO #include <sys/socket.h>
2965e96449SHajimu UMEMOTO 
3065e96449SHajimu UMEMOTO #include <netinet/in.h>
3165e96449SHajimu UMEMOTO #include <arpa/inet.h>
3265e96449SHajimu UMEMOTO #include <arpa/nameser.h>
3365e96449SHajimu UMEMOTO 
3465e96449SHajimu UMEMOTO #include <errno.h>
3565e96449SHajimu UMEMOTO #include <stdio.h>
3665e96449SHajimu UMEMOTO #include <string.h>
3765e96449SHajimu UMEMOTO 
3865e96449SHajimu UMEMOTO #include "port_after.h"
3965e96449SHajimu UMEMOTO 
40dde4a85dSHajimu UMEMOTO /*%
4165e96449SHajimu UMEMOTO  * WARNING: Don't even consider trying to compile this on a system where
4265e96449SHajimu UMEMOTO  * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
4365e96449SHajimu UMEMOTO  */
4465e96449SHajimu UMEMOTO 
45ab96eeabSHajimu UMEMOTO static const char *inet_ntop4(const u_char *src, char *dst, socklen_t size);
46ab96eeabSHajimu UMEMOTO static const char *inet_ntop6(const u_char *src, char *dst, socklen_t size);
4765e96449SHajimu UMEMOTO 
48*71099ec5SKevin Lo /* const char *
4965e96449SHajimu UMEMOTO  * inet_ntop(af, src, dst, size)
5065e96449SHajimu UMEMOTO  *	convert a network format address to presentation format.
5165e96449SHajimu UMEMOTO  * return:
5265e96449SHajimu UMEMOTO  *	pointer to presentation format address (`dst'), or NULL (see errno).
5365e96449SHajimu UMEMOTO  * author:
5465e96449SHajimu UMEMOTO  *	Paul Vixie, 1996.
5565e96449SHajimu UMEMOTO  */
5665e96449SHajimu UMEMOTO const char *
57ab96eeabSHajimu UMEMOTO inet_ntop(int af, const void * __restrict src, char * __restrict dst,
58ab96eeabSHajimu UMEMOTO     socklen_t size)
5965e96449SHajimu UMEMOTO {
6065e96449SHajimu UMEMOTO 	switch (af) {
6165e96449SHajimu UMEMOTO 	case AF_INET:
6265e96449SHajimu UMEMOTO 		return (inet_ntop4(src, dst, size));
6365e96449SHajimu UMEMOTO 	case AF_INET6:
6465e96449SHajimu UMEMOTO 		return (inet_ntop6(src, dst, size));
6565e96449SHajimu UMEMOTO 	default:
6665e96449SHajimu UMEMOTO 		errno = EAFNOSUPPORT;
6765e96449SHajimu UMEMOTO 		return (NULL);
6865e96449SHajimu UMEMOTO 	}
6965e96449SHajimu UMEMOTO 	/* NOTREACHED */
7065e96449SHajimu UMEMOTO }
7165e96449SHajimu UMEMOTO 
7265e96449SHajimu UMEMOTO /* const char *
7365e96449SHajimu UMEMOTO  * inet_ntop4(src, dst, size)
7465e96449SHajimu UMEMOTO  *	format an IPv4 address
7565e96449SHajimu UMEMOTO  * return:
7665e96449SHajimu UMEMOTO  *	`dst' (as a const)
7765e96449SHajimu UMEMOTO  * notes:
7865e96449SHajimu UMEMOTO  *	(1) uses no statics
7965e96449SHajimu UMEMOTO  *	(2) takes a u_char* not an in_addr as input
8065e96449SHajimu UMEMOTO  * author:
8165e96449SHajimu UMEMOTO  *	Paul Vixie, 1996.
8265e96449SHajimu UMEMOTO  */
8365e96449SHajimu UMEMOTO static const char *
84ab96eeabSHajimu UMEMOTO inet_ntop4(const u_char *src, char *dst, socklen_t size)
8565e96449SHajimu UMEMOTO {
8665e96449SHajimu UMEMOTO 	static const char fmt[] = "%u.%u.%u.%u";
8765e96449SHajimu UMEMOTO 	char tmp[sizeof "255.255.255.255"];
88ab96eeabSHajimu UMEMOTO 	int l;
8965e96449SHajimu UMEMOTO 
90ab96eeabSHajimu UMEMOTO 	l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
91ab96eeabSHajimu UMEMOTO 	if (l <= 0 || (socklen_t) l >= size) {
9265e96449SHajimu UMEMOTO 		errno = ENOSPC;
9365e96449SHajimu UMEMOTO 		return (NULL);
9465e96449SHajimu UMEMOTO 	}
95ab96eeabSHajimu UMEMOTO 	strlcpy(dst, tmp, size);
9665e96449SHajimu UMEMOTO 	return (dst);
9765e96449SHajimu UMEMOTO }
9865e96449SHajimu UMEMOTO 
9965e96449SHajimu UMEMOTO /* const char *
10065e96449SHajimu UMEMOTO  * inet_ntop6(src, dst, size)
10165e96449SHajimu UMEMOTO  *	convert IPv6 binary address into presentation (printable) format
10265e96449SHajimu UMEMOTO  * author:
10365e96449SHajimu UMEMOTO  *	Paul Vixie, 1996.
10465e96449SHajimu UMEMOTO  */
10565e96449SHajimu UMEMOTO static const char *
106ab96eeabSHajimu UMEMOTO inet_ntop6(const u_char *src, char *dst, socklen_t size)
10765e96449SHajimu UMEMOTO {
10865e96449SHajimu UMEMOTO 	/*
10965e96449SHajimu UMEMOTO 	 * Note that int32_t and int16_t need only be "at least" large enough
11065e96449SHajimu UMEMOTO 	 * to contain a value of the specified size.  On some systems, like
11165e96449SHajimu UMEMOTO 	 * Crays, there is no such thing as an integer variable with 16 bits.
11265e96449SHajimu UMEMOTO 	 * Keep this in mind if you think this function should have been coded
11365e96449SHajimu UMEMOTO 	 * to use pointer overlays.  All the world's not a VAX.
11465e96449SHajimu UMEMOTO 	 */
11565e96449SHajimu UMEMOTO 	char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
11665e96449SHajimu UMEMOTO 	struct { int base, len; } best, cur;
11765e96449SHajimu UMEMOTO 	u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
11865e96449SHajimu UMEMOTO 	int i;
11965e96449SHajimu UMEMOTO 
12065e96449SHajimu UMEMOTO 	/*
12165e96449SHajimu UMEMOTO 	 * Preprocess:
12265e96449SHajimu UMEMOTO 	 *	Copy the input (bytewise) array into a wordwise array.
12365e96449SHajimu UMEMOTO 	 *	Find the longest run of 0x00's in src[] for :: shorthanding.
12465e96449SHajimu UMEMOTO 	 */
12565e96449SHajimu UMEMOTO 	memset(words, '\0', sizeof words);
12665e96449SHajimu UMEMOTO 	for (i = 0; i < NS_IN6ADDRSZ; i++)
12765e96449SHajimu UMEMOTO 		words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
12865e96449SHajimu UMEMOTO 	best.base = -1;
12965e96449SHajimu UMEMOTO 	best.len = 0;
13065e96449SHajimu UMEMOTO 	cur.base = -1;
13165e96449SHajimu UMEMOTO 	cur.len = 0;
13265e96449SHajimu UMEMOTO 	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
13365e96449SHajimu UMEMOTO 		if (words[i] == 0) {
13465e96449SHajimu UMEMOTO 			if (cur.base == -1)
13565e96449SHajimu UMEMOTO 				cur.base = i, cur.len = 1;
13665e96449SHajimu UMEMOTO 			else
13765e96449SHajimu UMEMOTO 				cur.len++;
13865e96449SHajimu UMEMOTO 		} else {
13965e96449SHajimu UMEMOTO 			if (cur.base != -1) {
14065e96449SHajimu UMEMOTO 				if (best.base == -1 || cur.len > best.len)
14165e96449SHajimu UMEMOTO 					best = cur;
14265e96449SHajimu UMEMOTO 				cur.base = -1;
14365e96449SHajimu UMEMOTO 			}
14465e96449SHajimu UMEMOTO 		}
14565e96449SHajimu UMEMOTO 	}
14665e96449SHajimu UMEMOTO 	if (cur.base != -1) {
14765e96449SHajimu UMEMOTO 		if (best.base == -1 || cur.len > best.len)
14865e96449SHajimu UMEMOTO 			best = cur;
14965e96449SHajimu UMEMOTO 	}
15065e96449SHajimu UMEMOTO 	if (best.base != -1 && best.len < 2)
15165e96449SHajimu UMEMOTO 		best.base = -1;
15265e96449SHajimu UMEMOTO 
15365e96449SHajimu UMEMOTO 	/*
15465e96449SHajimu UMEMOTO 	 * Format the result.
15565e96449SHajimu UMEMOTO 	 */
15665e96449SHajimu UMEMOTO 	tp = tmp;
15765e96449SHajimu UMEMOTO 	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
15865e96449SHajimu UMEMOTO 		/* Are we inside the best run of 0x00's? */
15965e96449SHajimu UMEMOTO 		if (best.base != -1 && i >= best.base &&
16065e96449SHajimu UMEMOTO 		    i < (best.base + best.len)) {
16165e96449SHajimu UMEMOTO 			if (i == best.base)
16265e96449SHajimu UMEMOTO 				*tp++ = ':';
16365e96449SHajimu UMEMOTO 			continue;
16465e96449SHajimu UMEMOTO 		}
16565e96449SHajimu UMEMOTO 		/* Are we following an initial run of 0x00s or any real hex? */
16665e96449SHajimu UMEMOTO 		if (i != 0)
16765e96449SHajimu UMEMOTO 			*tp++ = ':';
16865e96449SHajimu UMEMOTO 		/* Is this address an encapsulated IPv4? */
16965e96449SHajimu UMEMOTO 		if (i == 6 && best.base == 0 && (best.len == 6 ||
17065e96449SHajimu UMEMOTO 		    (best.len == 7 && words[7] != 0x0001) ||
17165e96449SHajimu UMEMOTO 		    (best.len == 5 && words[5] == 0xffff))) {
172*71099ec5SKevin Lo 			if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) {
173*71099ec5SKevin Lo 				errno = ENOSPC;
17465e96449SHajimu UMEMOTO 				return (NULL);
175*71099ec5SKevin Lo 			}
17665e96449SHajimu UMEMOTO 			tp += strlen(tp);
17765e96449SHajimu UMEMOTO 			break;
17865e96449SHajimu UMEMOTO 		}
179ab96eeabSHajimu UMEMOTO 		tp += sprintf(tp, "%x", words[i]);
18065e96449SHajimu UMEMOTO 	}
18165e96449SHajimu UMEMOTO 	/* Was it a trailing run of 0x00's? */
18265e96449SHajimu UMEMOTO 	if (best.base != -1 && (best.base + best.len) ==
18365e96449SHajimu UMEMOTO 	    (NS_IN6ADDRSZ / NS_INT16SZ))
18465e96449SHajimu UMEMOTO 		*tp++ = ':';
18565e96449SHajimu UMEMOTO 	*tp++ = '\0';
18665e96449SHajimu UMEMOTO 
18765e96449SHajimu UMEMOTO 	/*
18865e96449SHajimu UMEMOTO 	 * Check for overflow, copy, and we're done.
18965e96449SHajimu UMEMOTO 	 */
190ab96eeabSHajimu UMEMOTO 	if ((socklen_t)(tp - tmp) > size) {
19165e96449SHajimu UMEMOTO 		errno = ENOSPC;
19265e96449SHajimu UMEMOTO 		return (NULL);
19365e96449SHajimu UMEMOTO 	}
19465e96449SHajimu UMEMOTO 	strcpy(dst, tmp);
19565e96449SHajimu UMEMOTO 	return (dst);
19665e96449SHajimu UMEMOTO }
197ab96eeabSHajimu UMEMOTO 
198ab96eeabSHajimu UMEMOTO /*
199ab96eeabSHajimu UMEMOTO  * Weak aliases for applications that use certain private entry points,
200ab96eeabSHajimu UMEMOTO  * and fail to include <arpa/inet.h>.
201ab96eeabSHajimu UMEMOTO  */
202ab96eeabSHajimu UMEMOTO #undef inet_ntop
203ab96eeabSHajimu UMEMOTO __weak_reference(__inet_ntop, inet_ntop);
204dde4a85dSHajimu UMEMOTO 
205dde4a85dSHajimu UMEMOTO /*! \file */
206