/* $NetBSD: inet_ntop.c,v 1.12 2018/03/02 06:31:53 lukem Exp $ */
/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* 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 ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC 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 <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static const char rcsid[] = "Id: inet_ntop.c,v 1.5 2005/11/03 22:59:52 marka Exp";
#else
__RCSID("$NetBSD: inet_ntop.c,v 1.12 2018/03/02 06:31:53 lukem Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include "port_before.h"
#include "namespace.h"
#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 <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "port_after.h"
#ifdef __weak_alias
__weak_alias(inet_ntop,_inet_ntop)
#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);
static const char *inet_ntop6(const u_char *src, char *dst, socklen_t size);
/* 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 *src, char *dst, socklen_t size)
{
_DIAGASSERT(src != NULL);
_DIAGASSERT(dst != NULL);
switch (af) {
case AF_INET:
return inet_ntop4(src, dst, size);
case AF_INET6:
return inet_ntop6(src, dst, size);
default:
errno = EAFNOSUPPORT;
return NULL;
}
/* NOTREACHED */
}
/* const char *
* inet_ntop4(src, dst, size)
* format an IPv4 address, more or less like inet_ntoa()
* 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 u_char *src, char *dst, socklen_t size)
{
char tmp[sizeof "255.255.255.255"];
int l;
_DIAGASSERT(src != NULL);
_DIAGASSERT(dst != NULL);
l = snprintf(tmp, sizeof(tmp), "%u.%u.%u.%u",
src[0], src[1], src[2], src[3]);
if (l <= 0 || (socklen_t) l >= size) {
errno = ENOSPC;
return NULL;
}
strlcpy(dst, tmp, size);
return dst;
}
/* 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 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"];
char *tp, *ep;
struct { int base, len; } best, cur;
u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
int i;
int advance;
_DIAGASSERT(src != NULL);
_DIAGASSERT(dst != NULL);
/*
* 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;
best.len = 0;
cur.base = -1;
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;
ep = tmp + sizeof(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) {
if (tp + 1 >= ep)
goto out;
*tp++ = ':';
}
/* Is this address an encapsulated IPv4? */
if (i == 6 && best.base == 0 &&
(best.len == 6 ||
(best.len == 7 && words[7] != 0x0001) ||
(best.len == 5 && words[5] == 0xffff))) {
if (!inet_ntop4(src + 12, tp, (socklen_t)(ep - tp)))
goto out;
tp += strlen(tp);
break;
}
advance = snprintf(tp, (size_t)(ep - tp), "%x", words[i]);
if (advance <= 0 || advance >= ep - tp)
goto out;
tp += advance;
}
/* Was it a trailing run of 0x00's? */
if (best.base != -1 && (best.base + best.len) ==
(NS_IN6ADDRSZ / NS_INT16SZ)) {
if (tp + 1 >= ep)
goto out;
*tp++ = ':';
}
if (tp + 1 >= ep)
goto out;
*tp++ = '\0';
/*
* Check for overflow, copy, and we're done.
*/
if ((size_t)(tp - tmp) > size)
goto out;
strlcpy(dst, tmp, size);
return dst;
out:
errno = ENOSPC;
return NULL;
}
/*! \file */
