blob: 8668bf6d1b20486b85436cc31e7a634f0a711459 [file] [log] [blame]
/* inet_ntop.c -- convert IPv4 and IPv6 addresses from binary to text form
Copyright (C) 2005-2006, 2008-2016 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>. */
/*
* 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.
*/
#include <config.h>
/* Specification. */
#include <arpa/inet.h>
/* Use this to suppress gcc's "...may be used before initialized" warnings.
Beware: The Code argument must not contain commas. */
#ifndef IF_LINT
# if defined GCC_LINT || defined lint
# define IF_LINT(Code) Code
# else
# define IF_LINT(Code) /* empty */
# endif
#endif
#if HAVE_DECL_INET_NTOP
# undef inet_ntop
const char *
rpl_inet_ntop (int af, const void *restrict src,
char *restrict dst, socklen_t cnt)
{
return inet_ntop (af, src, dst, cnt);
}
#else
# include <stdio.h>
# include <string.h>
# include <errno.h>
# define NS_IN6ADDRSZ 16
# define NS_INT16SZ 2
/*
* 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.
*/
typedef int verify_int_size[4 <= sizeof (int) ? 1 : -1];
static const char *inet_ntop4 (const unsigned char *src, char *dst, socklen_t size);
# if HAVE_IPV6
static const char *inet_ntop6 (const unsigned char *src, char *dst, socklen_t size);
# endif
/* 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 *restrict src,
char *restrict dst, socklen_t cnt)
{
switch (af)
{
# if HAVE_IPV4
case AF_INET:
return (inet_ntop4 (src, dst, cnt));
# endif
# if HAVE_IPV6
case AF_INET6:
return (inet_ntop6 (src, dst, cnt));
# 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 u_char* not an in_addr as input
* author:
* Paul Vixie, 1996.
*/
static const char *
inet_ntop4 (const unsigned char *src, char *dst, socklen_t size)
{
char tmp[sizeof "255.255.255.255"];
int len;
len = sprintf (tmp, "%u.%u.%u.%u", src[0], src[1], src[2], src[3]);
if (len < 0)
return NULL;
if (len > size)
{
errno = ENOSPC;
return NULL;
}
return strcpy (dst, tmp);
}
# if HAVE_IPV6
/* const char *
* inet_ntop6(src, dst, size)
* convert IPv6 binary address into presentation (printable) format
* author:
* Paul Vixie, 1996.
*/
static const char *
inet_ntop6 (const unsigned 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;
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 += 2)
words[i / 2] = (src[i] << 8) | src[i + 1];
best.base = -1;
cur.base = -1;
IF_LINT(best.len = 0);
IF_LINT(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 == 5 && words[5] == 0xffff)))
{
if (!inet_ntop4 (src + 12, tp, sizeof tmp - (tp - tmp)))
return (NULL);
tp += strlen (tp);
break;
}
{
int len = sprintf (tp, "%x", words[i]);
if (len < 0)
return NULL;
tp += len;
}
}
/* 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)
{
errno = ENOSPC;
return NULL;
}
return strcpy (dst, tmp);
}
# endif
#endif