[apple/xnu.git] / libkern / net / inet_ntop.c

/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1996-1999 by Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static const char rcsid[] = "$Id: inet_ntop.c,v 1.3.18.2 2005/11/03 23:02:22 marka Exp $";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/systm.h>

#include <netinet/in.h>

/*%
 * WARNING: Don't even consider trying to compile this on a system where
 * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
 */

static char	*inet_ntop4(const u_char *src, char *dst, socklen_t size);
static char	*inet_ntop6(const u_char *src, char *dst, socklen_t size);

/* char *
 * inet_ntop(af, src, dst, size)
 *	convert a network format address to presentation format.
 * return:
 *	pointer to presentation format address (`dst'), or NULL (see errno).
 * author:
 *	Paul Vixie, 1996.
 */
const char *
inet_ntop(int af, const void *src, char *dst, socklen_t size)
{
	switch (af) {
	case AF_INET:
		return (inet_ntop4(src, dst, size));
	case AF_INET6:
		return (inet_ntop6(src, dst, size));
	default:
		return (NULL);
	}
	/* NOTREACHED */
}

/* const char *
 * inet_ntop4(src, dst, size)
 *	format an IPv4 address
 * return:
 *	`dst' (as a const)
 * notes:
 *	(1) uses no statics
 *	(2) takes a u_char* not an in_addr as input
 * author:
 *	Paul Vixie, 1996.
 */
static char *
inet_ntop4(const u_char *src, char *dst, socklen_t size)
{
	static const char fmt[] = "%u.%u.%u.%u";
	char tmp[sizeof "255.255.255.255"];
	int l;

	l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
	if (l <= 0 || (socklen_t) l >= size) {
		return (NULL);
	}
	strlcpy(dst, tmp, size);
	return (dst);
}

/* const char *
 * inet_ntop6(src, dst, size)
 *	convert IPv6 binary address into presentation (printable) format
 * author:
 *	Paul Vixie, 1996.
 */
static char *
inet_ntop6(const u_char *src, char *dst, socklen_t size)
{
	/*
	 * Note that int32_t and int16_t need only be "at least" large enough
	 * to contain a value of the specified size.  On some systems, like
	 * Crays, there is no such thing as an integer variable with 16 bits.
	 * Keep this in mind if you think this function should have been coded
	 * to use pointer overlays.  All the world's not a VAX.
	 */
	char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
	struct { int base, len; } best, cur;
#define NS_IN6ADDRSZ	16
#define NS_INT16SZ	2
	u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
	int i;

	/*
	 * Preprocess:
	 *	Copy the input (bytewise) array into a wordwise array.
	 *	Find the longest run of 0x00's in src[] for :: shorthanding.
	 */
	memset(words, '\0', sizeof words);
	for (i = 0; i < NS_IN6ADDRSZ; i++)
		words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
	best.base = -1;
	best.len = 0;
	cur.base = -1;
	cur.len = 0;
	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
		if (words[i] == 0) {
			if (cur.base == -1) {
				cur.base = i;
				cur.len = 1;
			} else {
				cur.len++;
			}
		} else {
			if (cur.base != -1) {
				if (best.base == -1 || cur.len > best.len)
					best = cur;
				cur.base = -1;
			}
		}
	}
	if (cur.base != -1) {
		if (best.base == -1 || cur.len > best.len)
			best = cur;
	}
	if (best.base != -1 && best.len < 2)
		best.base = -1;

	/*
	 * Format the result.
	 */
	tp = tmp;
	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
		/* Are we inside the best run of 0x00's? */
		if (best.base != -1 && i >= best.base &&
		    i < (best.base + best.len)) {
			if (i == best.base)
				*tp++ = ':';
			continue;
		}
		/* Are we following an initial run of 0x00s or any real hex? */
		if (i != 0)
			*tp++ = ':';
		/* Is this address an encapsulated IPv4? */
		if (i == 6 && best.base == 0 && (best.len == 6 ||
		    (best.len == 7 && words[7] != 0x0001) ||
		    (best.len == 5 && words[5] == 0xffff))) {
			if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
				return (NULL);
			tp += strlen(tp);
			break;
		}
		tp += snprintf(tp, sizeof(tmp), "%x", words[i]);
	}
	/* Was it a trailing run of 0x00's? */
	if (best.base != -1 && (best.base + best.len) == 
	    (NS_IN6ADDRSZ / NS_INT16SZ))
		*tp++ = ':';
	*tp++ = '\0';

	/*
	 * Check for overflow, copy, and we're done.
	 */
	if ((socklen_t)(tp - tmp) > size) {
		return (NULL);
	}
	strlcpy(dst, tmp, size);
	return (dst);
}

/*! \file */
Commit	Line	Data
39236c6e A	1	/*
	2	* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
	3	* Copyright (c) 1996-1999 by Internet Software Consortium.
	4	*
	5	* Permission to use, copy, modify, and distribute this software for any
	6	* purpose with or without fee is hereby granted, provided that the above
	7	* copyright notice and this permission notice appear in all copies.
	8	*
	9	* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
	10	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	11	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
	12	* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	13	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
	14	* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
	15	* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	16	*/
	17
	18	#if defined(LIBC_SCCS) && !defined(lint)
	19	static const char rcsid[] = "$Id: inet_ntop.c,v 1.3.18.2 2005/11/03 23:02:22 marka Exp $";
	20	#endif /* LIBC_SCCS and not lint */
	21
	22	#include <sys/param.h>
	23	#include <sys/socket.h>
	24	#include <sys/systm.h>
	25
	26	#include <netinet/in.h>
	27
	28	/*%
	29	* WARNING: Don't even consider trying to compile this on a system where
	30	* sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
	31	*/
	32
	33	static char inet_ntop4(const u_char src, char *dst, socklen_t size);
	34	static char inet_ntop6(const u_char src, char *dst, socklen_t size);
	35
	36	/* char *
	37	* inet_ntop(af, src, dst, size)
	38	* convert a network format address to presentation format.
	39	* return:
	40	* pointer to presentation format address (`dst'), or NULL (see errno).
	41	* author:
	42	* Paul Vixie, 1996.
	43	*/
	44	const char *
	45	inet_ntop(int af, const void src, char dst, socklen_t size)
	46	{
	47	switch (af) {
	48	case AF_INET:
	49	return (inet_ntop4(src, dst, size));
	50	case AF_INET6:
	51	return (inet_ntop6(src, dst, size));
	52	default:
	53	return (NULL);
	54	}
	55	/* NOTREACHED */
	56	}
	57
	58	/* const char *
	59	* inet_ntop4(src, dst, size)
	60	* format an IPv4 address
	61	* return:
	62	* `dst' (as a const)
	63	* notes:
	64	* (1) uses no statics
65	* (2) takes a u_char* not an in_addr as input
66	* author:
67	* Paul Vixie, 1996.
68	*/
69	static char *
70	inet_ntop4(const u_char src, char dst, socklen_t size)
71	{
72	static const char fmt[] = "%u.%u.%u.%u";
73	char tmp[sizeof "255.255.255.255"];
74	int l;
75
76	l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
77	if (l <= 0 \|\| (socklen_t) l >= size) {
78	return (NULL);
79	}
80	strlcpy(dst, tmp, size);
81	return (dst);
82	}
83
84	/* const char *
85	* inet_ntop6(src, dst, size)
86	* convert IPv6 binary address into presentation (printable) format
87	* author:
88	* Paul Vixie, 1996.
89	*/
90	static char *
91	inet_ntop6(const u_char src, char dst, socklen_t size)
92	{
93	/*
94	* Note that int32_t and int16_t need only be "at least" large enough
95	* to contain a value of the specified size. On some systems, like
96	* Crays, there is no such thing as an integer variable with 16 bits.
97	* Keep this in mind if you think this function should have been coded
98	* to use pointer overlays. All the world's not a VAX.
99	*/
100	char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
101	struct { int base, len; } best, cur;
102	#define NS_IN6ADDRSZ 16
103	#define NS_INT16SZ 2
104	u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
105	int i;
106
107	/*
108	* Preprocess:
109	* Copy the input (bytewise) array into a wordwise array.
110	* Find the longest run of 0x00's in src[] for :: shorthanding.
111	*/
112	memset(words, '\0', sizeof words);
113	for (i = 0; i < NS_IN6ADDRSZ; i++)
114	words[i / 2] \|= (src[i] << ((1 - (i % 2)) << 3));
115	best.base = -1;
116	best.len = 0;
117	cur.base = -1;
118	cur.len = 0;
119	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
120	if (words[i] == 0) {
39037602 A	121	if (cur.base == -1) {
	122	cur.base = i;
	123	cur.len = 1;
	124	} else {
39236c6e	125	cur.len++;
39037602	126	}
39236c6e A	127	} else {
	128	if (cur.base != -1) {
	129	if (best.base == -1 \|\| cur.len > best.len)
	130	best = cur;
	131	cur.base = -1;
	132	}
	133	}
	134	}
	135	if (cur.base != -1) {
	136	if (best.base == -1 \|\| cur.len > best.len)
	137	best = cur;
	138	}
	139	if (best.base != -1 && best.len < 2)
	140	best.base = -1;
	141
	142	/*
	143	* Format the result.
	144	*/
	145	tp = tmp;
	146	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
	147	/* Are we inside the best run of 0x00's? */
	148	if (best.base != -1 && i >= best.base &&
	149	i < (best.base + best.len)) {
	150	if (i == best.base)
	151	*tp++ = ':';
	152	continue;
	153	}
	154	/* Are we following an initial run of 0x00s or any real hex? */
	155	if (i != 0)
	156	*tp++ = ':';
	157	/* Is this address an encapsulated IPv4? */
	158	if (i == 6 && best.base == 0 && (best.len == 6 \|\|
	159	(best.len == 7 && words[7] != 0x0001) \|\|
	160	(best.len == 5 && words[5] == 0xffff))) {
	161	if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
	162	return (NULL);
	163	tp += strlen(tp);
	164	break;
	165	}
	166	tp += snprintf(tp, sizeof(tmp), "%x", words[i]);
	167	}
	168	/* Was it a trailing run of 0x00's? */
	169	if (best.base != -1 && (best.base + best.len) ==
	170	(NS_IN6ADDRSZ / NS_INT16SZ))
	171	*tp++ = ':';
	172	*tp++ = '\0';
	173
	174	/*
	175	* Check for overflow, copy, and we're done.
	176	*/
	177	if ((socklen_t)(tp - tmp) > size) {
	178	return (NULL);
	179	}
	180	strlcpy(dst, tmp, size);
	181	return (dst);
	182	}
	183
	184	/! \file /