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/*
* 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char rcsid[] =
"$ISC: inet_ntop.c,v 1.12 2001/01/25 20:10:01 gson Exp $";
#endif /* LIBC_SCCS and not lint */
#include <config.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <isc/net.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 *
isc_net_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"];
if ((size_t)snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]) >= size)
{
errno = ENOSPC;
return (NULL);
}
strlcpy(dst, tmp, size);
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;
/*
* 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;
}
snprintf(tp, tmp + sizeof tmp - tp, "%x", words[i]);
tp += strlen(tp);
}
/* 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);
}
strlcpy(dst, tmp, size);
return (dst);
}
#endif /* AF_INET6 */
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