260 lines
6.8 KiB
C
260 lines
6.8 KiB
C
/* inet_ntop.c -- convert IPv4 and IPv6 addresses from binary to text form
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Copyright (C) 2005-2006, 2008-2023 Free Software Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/*
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* Copyright (c) 1996-1999 by Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
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* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
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* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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#include <config.h>
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/* Specification. */
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#include <arpa/inet.h>
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/* Use this to suppress gcc's "...may be used before initialized" warnings.
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Beware: The Code argument must not contain commas. */
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#ifndef IF_LINT
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# if defined GCC_LINT || defined lint
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# define IF_LINT(Code) Code
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# else
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# define IF_LINT(Code) /* empty */
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# endif
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#endif
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#if HAVE_DECL_INET_NTOP
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# undef inet_ntop
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const char *
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rpl_inet_ntop (int af, const void *restrict src,
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char *restrict dst, socklen_t cnt)
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{
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return inet_ntop (af, src, dst, cnt);
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}
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#else
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# include <stdio.h>
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# include <string.h>
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# include <errno.h>
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# define NS_IN6ADDRSZ 16
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# define NS_INT16SZ 2
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/*
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* WARNING: Don't even consider trying to compile this on a system where
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* sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX.
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*/
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typedef int verify_int_size[4 <= sizeof (int) ? 1 : -1];
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static const char *inet_ntop4 (const unsigned char *src, char *dst, socklen_t size);
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# if HAVE_IPV6
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static const char *inet_ntop6 (const unsigned char *src, char *dst, socklen_t size);
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# endif
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/* char *
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* inet_ntop(af, src, dst, size)
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* convert a network format address to presentation format.
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* return:
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* pointer to presentation format address ('dst'), or NULL (see errno).
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* author:
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* Paul Vixie, 1996.
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*/
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const char *
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inet_ntop (int af, const void *restrict src,
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char *restrict dst, socklen_t cnt)
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{
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switch (af)
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{
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# if HAVE_IPV4
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case AF_INET:
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return (inet_ntop4 (src, dst, cnt));
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# endif
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# if HAVE_IPV6
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case AF_INET6:
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return (inet_ntop6 (src, dst, cnt));
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# endif
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default:
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errno = EAFNOSUPPORT;
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return (NULL);
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}
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/* NOTREACHED */
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}
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/* const char *
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* inet_ntop4(src, dst, size)
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* format an IPv4 address
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* return:
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* 'dst' (as a const)
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* notes:
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* (1) uses no statics
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* (2) takes a u_char* not an in_addr as input
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* author:
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* Paul Vixie, 1996.
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*/
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static const char *
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inet_ntop4 (const unsigned char *src, char *dst, socklen_t size)
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{
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char tmp[sizeof "255.255.255.255"];
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int len;
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len = sprintf (tmp, "%u.%u.%u.%u", src[0], src[1], src[2], src[3]);
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if (len < 0)
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return NULL;
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if (len > size)
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{
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errno = ENOSPC;
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return NULL;
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}
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return strcpy (dst, tmp);
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}
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# if HAVE_IPV6
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/* const char *
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* inet_ntop6(src, dst, size)
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* convert IPv6 binary address into presentation (printable) format
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* author:
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* Paul Vixie, 1996.
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*/
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static const char *
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inet_ntop6 (const unsigned char *src, char *dst, socklen_t size)
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{
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/*
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* Note that int32_t and int16_t need only be "at least" large enough
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* to contain a value of the specified size. On some systems, like
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* Crays, there is no such thing as an integer variable with 16 bits.
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* Keep this in mind if you think this function should have been coded
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* to use pointer overlays. All the world's not a VAX.
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*/
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char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
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struct
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{
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int base, len;
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} best, cur;
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unsigned int words[NS_IN6ADDRSZ / NS_INT16SZ];
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int i;
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/*
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* Preprocess:
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* Copy the input (bytewise) array into a wordwise array.
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* Find the longest run of 0x00's in src[] for :: shorthanding.
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*/
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memset (words, '\0', sizeof words);
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for (i = 0; i < NS_IN6ADDRSZ; i += 2)
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words[i / 2] = (src[i] << 8) | src[i + 1];
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best.base = -1;
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cur.base = -1;
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IF_LINT(best.len = 0);
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IF_LINT(cur.len = 0);
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for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++)
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{
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if (words[i] == 0)
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{
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if (cur.base == -1)
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cur.base = i, cur.len = 1;
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else
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cur.len++;
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}
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else
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{
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if (cur.base != -1)
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{
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if (best.base == -1 || cur.len > best.len)
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best = cur;
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cur.base = -1;
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}
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}
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}
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if (cur.base != -1)
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{
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if (best.base == -1 || cur.len > best.len)
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best = cur;
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}
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if (best.base != -1 && best.len < 2)
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best.base = -1;
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/*
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* Format the result.
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*/
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tp = tmp;
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for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++)
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{
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/* Are we inside the best run of 0x00's? */
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if (best.base != -1 && i >= best.base && i < (best.base + best.len))
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{
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if (i == best.base)
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*tp++ = ':';
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continue;
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}
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/* Are we following an initial run of 0x00s or any real hex? */
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if (i != 0)
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*tp++ = ':';
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/* Is this address an encapsulated IPv4? */
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if (i == 6 && best.base == 0 &&
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(best.len == 6 || (best.len == 5 && words[5] == 0xffff)))
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{
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if (!inet_ntop4 (src + 12, tp, sizeof tmp - (tp - tmp)))
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return (NULL);
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tp += strlen (tp);
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break;
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}
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{
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int len = sprintf (tp, "%x", words[i]);
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if (len < 0)
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return NULL;
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tp += len;
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}
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}
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/* Was it a trailing run of 0x00's? */
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if (best.base != -1 && (best.base + best.len) ==
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(NS_IN6ADDRSZ / NS_INT16SZ))
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*tp++ = ':';
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*tp++ = '\0';
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/*
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* Check for overflow, copy, and we're done.
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*/
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if ((socklen_t) (tp - tmp) > size)
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{
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errno = ENOSPC;
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return NULL;
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}
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return strcpy (dst, tmp);
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}
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# endif
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#endif
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