[rsync/rsync.git] / lib / inet_ntop.c

/*
 * Copyright (C) 1996-2001  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 INTERNET SOFTWARE CONSORTIUM
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * INTERNET SOFTWARE CONSORTIUM 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.
 */


#include "rsync.h"

#define NS_INT16SZ	 2
#define NS_IN6ADDRSZ	16

/*
 * 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 const char *inet_ntop4(const unsigned char *src, char *dst,
			      size_t size);

#ifdef AF_INET6
static const char *inet_ntop6(const unsigned char *src, char *dst,
			      size_t size);
#endif

/* char *
 * isc_net_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, size_t size)
{
	switch (af) {
	case AF_INET:
		return (inet_ntop4(src, dst, size));
#ifdef AF_INET6
	case AF_INET6:
		return (inet_ntop6(src, dst, size));
#endif
	default:
		errno = EAFNOSUPPORT;
		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 unsigned char* not an in_addr as input
 * author:
 *	Paul Vixie, 1996.
 */
static const char *
inet_ntop4(const unsigned char *src, char *dst, size_t size)
{
	static const char *fmt = "%u.%u.%u.%u";
	char tmp[sizeof "255.255.255.255"];
	size_t len;

	len = snprintf(tmp, sizeof tmp, fmt, src[0], src[1], src[2], src[3]);
	if (len >= size) {
		errno = ENOSPC;
		return (NULL);
	}
	memcpy(dst, tmp, len + 1);

	return (dst);
}

/* const char *
 * isc_inet_ntop6(src, dst, size)
 *	convert IPv6 binary address into presentation (printable) format
 * author:
 *	Paul Vixie, 1996.
 */
#ifdef AF_INET6
static const char *
inet_ntop6(const unsigned char *src, char *dst, size_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;
	unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
	int i, inc;

	/*
	 * 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;
	cur.base = -1;
	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 == 5 && words[5] == 0xffff))) {
			if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
				return (NULL);
			tp += strlen(tp);
			break;
		}
		inc = snprintf(tp, 5, "%x", words[i]);
		assert(inc < 5);
		tp += inc;
	}
	/* 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 ((size_t)(tp - tmp) > size) {
		errno = ENOSPC;
		return (NULL);
	}
	memcpy(dst, tmp, tp - tmp);
	return (dst);
}
#endif /* AF_INET6 */
Commit	Line	Data
8f694072 MP	1	/*
	2	* Copyright (C) 1996-2001 Internet Software Consortium.
	3	*
	4	* Permission to use, copy, modify, and distribute this software for any
	5	* purpose with or without fee is hereby granted, provided that the above
	6	* copyright notice and this permission notice appear in all copies.
	7	*
	8	* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
	9	* DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
	10	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
	11	* INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
	12	* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
	13	* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
	14	* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
	15	* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	16	*/
	17
8f694072	18
3723efcb	19	#include "rsync.h"
8f694072 MP	20
	21	#define NS_INT16SZ 2
	22	#define NS_IN6ADDRSZ 16
	23
	24	/*
	25	* WARNING: Don't even consider trying to compile this on a system where
	26	* sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
	27	*/
	28
	29	static const char inet_ntop4(const unsigned char src, char *dst,
	30	size_t size);
	31
	32	#ifdef AF_INET6
	33	static const char inet_ntop6(const unsigned char src, char *dst,
	34	size_t size);
	35	#endif
	36
	37	/* char *
	38	* isc_net_ntop(af, src, dst, size)
	39	* convert a network format address to presentation format.
	40	* return:
	41	* pointer to presentation format address (`dst'), or NULL (see errno).
	42	* author:
	43	* Paul Vixie, 1996.
	44	*/
	45	const char *
09b6f4b0	46	inet_ntop(int af, const void src, char dst, size_t size)
8f694072 MP	47	{
	48	switch (af) {
	49	case AF_INET:
	50	return (inet_ntop4(src, dst, size));
	51	#ifdef AF_INET6
	52	case AF_INET6:
	53	return (inet_ntop6(src, dst, size));
	54	#endif
	55	default:
	56	errno = EAFNOSUPPORT;
	57	return (NULL);
	58	}
	59	/* NOTREACHED */
	60	}
	61
	62	/* const char *
	63	* inet_ntop4(src, dst, size)
	64	* format an IPv4 address
	65	* return:
	66	* `dst' (as a const)
	67	* notes:
	68	* (1) uses no statics
	69	* (2) takes a unsigned char* not an in_addr as input
	70	* author:
	71	* Paul Vixie, 1996.
	72	*/
	73	static const char *
	74	inet_ntop4(const unsigned char src, char dst, size_t size)
	75	{
	76	static const char *fmt = "%u.%u.%u.%u";
	77	char tmp[sizeof "255.255.255.255"];
f210dcad	78	size_t len;
8f694072	79
f210dcad WD	80	len = snprintf(tmp, sizeof tmp, fmt, src[0], src[1], src[2], src[3]);
f210dcad WD	81	if (len >= size) {
8f694072 MP	82	errno = ENOSPC;
	83	return (NULL);
	84	}
204f4f4d	85	memcpy(dst, tmp, len + 1);
8f694072 MP	86
	87	return (dst);
	88	}
	89
	90	/* const char *
	91	* isc_inet_ntop6(src, dst, size)
	92	* convert IPv6 binary address into presentation (printable) format
	93	* author:
	94	* Paul Vixie, 1996.
	95	*/
	96	#ifdef AF_INET6
	97	static const char *
	98	inet_ntop6(const unsigned char src, char dst, size_t size)
	99	{
	100	/*
	101	* Note that int32_t and int16_t need only be "at least" large enough
	102	* to contain a value of the specified size. On some systems, like
	103	* Crays, there is no such thing as an integer variable with 16 bits.
	104	* Keep this in mind if you think this function should have been coded
	105	* to use pointer overlays. All the world's not a VAX.
	106	*/
	107	char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
	108	struct { int base, len; } best, cur;
	109	unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
f210dcad	110	int i, inc;
8f694072 MP	111
	112	/*
	113	* Preprocess:
	114	* Copy the input (bytewise) array into a wordwise array.
	115	* Find the longest run of 0x00's in src[] for :: shorthanding.
	116	*/
	117	memset(words, '\0', sizeof words);
	118	for (i = 0; i < NS_IN6ADDRSZ; i++)
	119	words[i / 2] \|= (src[i] << ((1 - (i % 2)) << 3));
	120	best.base = -1;
	121	cur.base = -1;
	122	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
	123	if (words[i] == 0) {
	124	if (cur.base == -1)
	125	cur.base = i, cur.len = 1;
	126	else
	127	cur.len++;
	128	} else {
	129	if (cur.base != -1) {
	130	if (best.base == -1 \|\| cur.len > best.len)
	131	best = cur;
	132	cur.base = -1;
	133	}
	134	}
	135	}
	136	if (cur.base != -1) {
	137	if (best.base == -1 \|\| cur.len > best.len)
	138	best = cur;
	139	}
	140	if (best.base != -1 && best.len < 2)
	141	best.base = -1;
	142
	143	/*
	144	* Format the result.
	145	*/
	146	tp = tmp;
	147	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
	148	/* Are we inside the best run of 0x00's? */
	149	if (best.base != -1 && i >= best.base &&
	150	i < (best.base + best.len)) {
	151	if (i == best.base)
	152	*tp++ = ':';
	153	continue;
	154	}
	155	/* Are we following an initial run of 0x00s or any real hex? */
	156	if (i != 0)
	157	*tp++ = ':';
	158	/* Is this address an encapsulated IPv4? */
	159	if (i == 6 && best.base == 0 &&
	160	(best.len == 6 \|\| (best.len == 5 && words[5] == 0xffff))) {
f210dcad	161	if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
8f694072 MP	162	return (NULL);
	163	tp += strlen(tp);
	164	break;
	165	}
f210dcad WD	166	inc = snprintf(tp, 5, "%x", words[i]);
	167	assert(inc < 5);
	168	tp += inc;
8f694072 MP	169	}
	170	/* Was it a trailing run of 0x00's? */
	171	if (best.base != -1 && (best.base + best.len) ==
	172	(NS_IN6ADDRSZ / NS_INT16SZ))
	173	*tp++ = ':';
	174	*tp++ = '\0';
	175
	176	/*
	177	* Check for overflow, copy, and we're done.
	178	*/
	179	if ((size_t)(tp - tmp) > size) {
	180	errno = ENOSPC;
	181	return (NULL);
	182	}
204f4f4d	183	memcpy(dst, tmp, tp - tmp);
8f694072 MP	184	return (dst);
	185	}
	186	#endif /* AF_INET6 */