[thirdparty/glibc.git] / resolv / inet_ntop.c

/*
 * 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 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static const char rcsid[] = "$BINDId: inet_ntop.c,v 1.8 1999/10/13 16:39:28 vixie Exp $";
#endif /* LIBC_SCCS and not lint */

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

#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>

#include <errno.h>
#include <stdio.h>
#include <string.h>

#ifdef SPRINTF_CHAR
# define SPRINTF(x) strlen(sprintf/**/x)
#else
# define SPRINTF(x) ((size_t)sprintf x)
#endif

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

/* 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(af, src, dst, size)
	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:
		__set_errno (EAFNOSUPPORT);
		return (NULL);
	}
	/* NOTREACHED */
}
libc_hidden_def (inet_ntop)

/* 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 const char *
internal_function
inet_ntop4(src, dst, size)
	const u_char *src;
	char *dst;
	socklen_t size;
{
	static const char fmt[] = "%u.%u.%u.%u";
	char tmp[sizeof "255.255.255.255"];

	if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) {
		__set_errno (ENOSPC);
		return (NULL);
	}
	return strcpy(dst, tmp);
}

/* const char *
 * inet_ntop6(src, dst, size)
 *	convert IPv6 binary address into presentation (printable) format
 * author:
 *	Paul Vixie, 1996.
 */
static const char *
internal_function
inet_ntop6(src, dst, size)
	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;
	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 += 2)
		words[i / 2] = (src[i] << 8) | src[i + 1];
	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;
		}
		tp += SPRINTF((tp, "%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) {
		__set_errno (ENOSPC);
		return (NULL);
	}
	return strcpy(dst, tmp);
}
Commit	Line	Data
e685e07d UD	1	/*
e685e07d UD	2	* Copyright (c) 1996-1999 by Internet Software Consortium.
fa0bc87c RM	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 DISCLAIMS
	9	* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
	10	* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
	11	* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
	12	* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
	13	* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
	14	* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
	15	* SOFTWARE.
	16	*/
	17
	18	#if defined(LIBC_SCCS) && !defined(lint)
e685e07d	19	static const char rcsid[] = "$BINDId: inet_ntop.c,v 1.8 1999/10/13 16:39:28 vixie Exp $";
fa0bc87c RM	20	#endif /* LIBC_SCCS and not lint */
	21
	22	#include <sys/param.h>
	23	#include <sys/types.h>
	24	#include <sys/socket.h>
e685e07d	25
fa0bc87c RM	26	#include <netinet/in.h>
	27	#include <arpa/inet.h>
	28	#include <arpa/nameser.h>
e685e07d	29
fa0bc87c RM	30	#include <errno.h>
fa0bc87c RM	31	#include <stdio.h>
e685e07d	32	#include <string.h>
fa0bc87c	33
613a76ff RM	34	#ifdef SPRINTF_CHAR
	35	# define SPRINTF(x) strlen(sprintf/**/x)
	36	#else
df21c858	37	# define SPRINTF(x) ((size_t)sprintf x)
613a76ff RM	38	#endif
613a76ff RM	39
fa0bc87c RM	40	/*
	41	* WARNING: Don't even consider trying to compile this on a system where
	42	* sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
	43	*/
	44
e685e07d	45	static const char inet_ntop4 (const u_char src, char *dst, socklen_t size)
dfd2257a	46	internal_function;
e685e07d	47	static const char inet_ntop6 (const u_char src, char *dst, socklen_t size)
dfd2257a	48	internal_function;
fa0bc87c RM	49
	50	/* char *
	51	* inet_ntop(af, src, dst, size)
	52	* convert a network format address to presentation format.
	53	* return:
	54	* pointer to presentation format address (`dst'), or NULL (see errno).
	55	* author:
	56	* Paul Vixie, 1996.
	57	*/
	58	const char *
	59	inet_ntop(af, src, dst, size)
	60	int af;
	61	const void *src;
	62	char *dst;
a1303dc8	63	socklen_t size;
fa0bc87c RM	64	{
	65	switch (af) {
	66	case AF_INET:
	67	return (inet_ntop4(src, dst, size));
	68	case AF_INET6:
	69	return (inet_ntop6(src, dst, size));
	70	default:
c4029823	71	__set_errno (EAFNOSUPPORT);
fa0bc87c RM	72	return (NULL);
	73	}
	74	/* NOTREACHED */
	75	}
c5598d47	76	libc_hidden_def (inet_ntop)
fa0bc87c RM	77
	78	/* const char *
	79	* inet_ntop4(src, dst, size)
e685e07d	80	* format an IPv4 address
fa0bc87c RM	81	* return:
	82	* `dst' (as a const)
	83	* notes:
	84	* (1) uses no statics
	85	* (2) takes a u_char* not an in_addr as input
	86	* author:
	87	* Paul Vixie, 1996.
	88	*/
	89	static const char *
dfd2257a	90	internal_function
fa0bc87c RM	91	inet_ntop4(src, dst, size)
	92	const u_char *src;
	93	char *dst;
a1303dc8	94	socklen_t size;
fa0bc87c RM	95	{
	96	static const char fmt[] = "%u.%u.%u.%u";
	97	char tmp[sizeof "255.255.255.255"];
	98
11bf311e	99	if (SPRINTF((tmp, fmt, src[0], src[1], src[2], src[3])) > size) {
c4029823	100	__set_errno (ENOSPC);
fa0bc87c RM	101	return (NULL);
fa0bc87c RM	102	}
fcb59416	103	return strcpy(dst, tmp);
fa0bc87c RM	104	}
	105
	106	/* const char *
	107	* inet_ntop6(src, dst, size)
	108	* convert IPv6 binary address into presentation (printable) format
	109	* author:
	110	* Paul Vixie, 1996.
	111	*/
	112	static const char *
dfd2257a	113	internal_function
fa0bc87c RM	114	inet_ntop6(src, dst, size)
	115	const u_char *src;
	116	char *dst;
a1303dc8	117	socklen_t size;
fa0bc87c RM	118	{
	119	/*
	120	* Note that int32_t and int16_t need only be "at least" large enough
	121	* to contain a value of the specified size. On some systems, like
	122	* Crays, there is no such thing as an integer variable with 16 bits.
	123	* Keep this in mind if you think this function should have been coded
	124	* to use pointer overlays. All the world's not a VAX.
	125	*/
	126	char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
	127	struct { int base, len; } best, cur;
e685e07d	128	u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
fa0bc87c RM	129	int i;
	130
	131	/*
	132	* Preprocess:
	133	* Copy the input (bytewise) array into a wordwise array.
	134	* Find the longest run of 0x00's in src[] for :: shorthanding.
	135	*/
df21c858	136	memset(words, '\0', sizeof words);
e685e07d	137	for (i = 0; i < NS_IN6ADDRSZ; i += 2)
fcb59416	138	words[i / 2] = (src[i] << 8) \| src[i + 1];
fa0bc87c RM	139	best.base = -1;
fa0bc87c RM	140	cur.base = -1;
e685e07d	141	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
fa0bc87c RM	142	if (words[i] == 0) {
	143	if (cur.base == -1)
	144	cur.base = i, cur.len = 1;
	145	else
	146	cur.len++;
	147	} else {
	148	if (cur.base != -1) {
	149	if (best.base == -1 \|\| cur.len > best.len)
	150	best = cur;
	151	cur.base = -1;
	152	}
	153	}
	154	}
	155	if (cur.base != -1) {
	156	if (best.base == -1 \|\| cur.len > best.len)
	157	best = cur;
	158	}
	159	if (best.base != -1 && best.len < 2)
	160	best.base = -1;
	161
	162	/*
	163	* Format the result.
	164	*/
	165	tp = tmp;
e685e07d	166	for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) {
fa0bc87c RM	167	/* Are we inside the best run of 0x00's? */
	168	if (best.base != -1 && i >= best.base &&
	169	i < (best.base + best.len)) {
	170	if (i == best.base)
	171	*tp++ = ':';
	172	continue;
	173	}
	174	/* Are we following an initial run of 0x00s or any real hex? */
	175	if (i != 0)
	176	*tp++ = ':';
	177	/* Is this address an encapsulated IPv4? */
	178	if (i == 6 && best.base == 0 &&
	179	(best.len == 6 \|\| (best.len == 5 && words[5] == 0xffff))) {
	180	if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
	181	return (NULL);
	182	tp += strlen(tp);
	183	break;
	184	}
613a76ff	185	tp += SPRINTF((tp, "%x", words[i]));
fa0bc87c RM	186	}
fa0bc87c RM	187	/* Was it a trailing run of 0x00's? */
c5598d47	188	if (best.base != -1 && (best.base + best.len) ==
e685e07d	189	(NS_IN6ADDRSZ / NS_INT16SZ))
fa0bc87c RM	190	*tp++ = ':';
	191	*tp++ = '\0';
	192
	193	/*
	194	* Check for overflow, copy, and we're done.
	195	*/
a1303dc8	196	if ((socklen_t)(tp - tmp) > size) {
c4029823	197	__set_errno (ENOSPC);
fa0bc87c RM	198	return (NULL);
fa0bc87c RM	199	}
fcb59416	200	return strcpy(dst, tmp);
fa0bc87c	201	}