freebsd-dev/lib/libc/inet/inet_cidr_ntop.c

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/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Copyright (c) 1998,1999 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static const char rcsid[] = "$Id: inet_cidr_ntop.c,v 1.7 2006/10/11 02:18:18 marka Exp $";
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#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
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#include "port_before.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "port_after.h"
#ifdef SPRINTF_CHAR
# define SPRINTF(x) strlen(sprintf/**/x)
#else
# define SPRINTF(x) ((size_t)sprintf x)
#endif
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static char *
inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size);
static char *
inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size);
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/*%
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* char *
* inet_cidr_ntop(af, src, bits, dst, size)
* convert network address from network to presentation format.
* "src"'s size is determined from its "af".
* return:
* pointer to dst, or NULL if an error occurred (check errno).
* note:
* 192.5.5.1/28 has a nonzero host part, which means it isn't a network
* as called for by inet_net_ntop() but it can be a host address with
* an included netmask.
* author:
* Paul Vixie (ISC), October 1998
*/
char *
inet_cidr_ntop(int af, const void *src, int bits, char *dst, size_t size) {
switch (af) {
case AF_INET:
return (inet_cidr_ntop_ipv4(src, bits, dst, size));
case AF_INET6:
return (inet_cidr_ntop_ipv6(src, bits, dst, size));
default:
errno = EAFNOSUPPORT;
return (NULL);
}
}
static int
decoct(const u_char *src, int bytes, char *dst, size_t size) {
char *odst = dst;
char *t;
int b;
for (b = 1; b <= bytes; b++) {
if (size < sizeof "255.")
return (0);
t = dst;
dst += SPRINTF((dst, "%u", *src++));
if (b != bytes) {
*dst++ = '.';
*dst = '\0';
}
size -= (size_t)(dst - t);
}
return (dst - odst);
}
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/*%
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* static char *
* inet_cidr_ntop_ipv4(src, bits, dst, size)
* convert IPv4 network address from network to presentation format.
* "src"'s size is determined from its "af".
* return:
* pointer to dst, or NULL if an error occurred (check errno).
* note:
* network byte order assumed. this means 192.5.5.240/28 has
* 0b11110000 in its fourth octet.
* author:
* Paul Vixie (ISC), October 1998
*/
static char *
inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size) {
char *odst = dst;
size_t len = 4;
size_t b;
size_t bytes;
if ((bits < -1) || (bits > 32)) {
errno = EINVAL;
return (NULL);
}
/* Find number of significant bytes in address. */
if (bits == -1)
len = 4;
else
for (len = 1, b = 1 ; b < 4U; b++)
if (*(src + b))
len = b + 1;
/* Format whole octets plus nonzero trailing octets. */
bytes = (((bits <= 0) ? 1 : bits) + 7) / 8;
if (len > bytes)
bytes = len;
b = decoct(src, bytes, dst, size);
if (b == 0U)
goto emsgsize;
dst += b;
size -= b;
if (bits != -1) {
/* Format CIDR /width. */
if (size < sizeof "/32")
goto emsgsize;
dst += SPRINTF((dst, "/%u", bits));
}
return (odst);
emsgsize:
errno = EMSGSIZE;
return (NULL);
}
static char *
inet_cidr_ntop_ipv6(const u_char *src, int bits, 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:255.255.255.255/128"];
char *tp;
struct { int base, len; } best, cur;
u_int words[NS_IN6ADDRSZ / NS_INT16SZ];
int i;
if ((bits < -1) || (bits > 128)) {
errno = EINVAL;
return (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;
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 == 7 && words[7] != 0x0001) ||
(best.len == 5 && words[5] == 0xffff))) {
int n;
if (src[15] || bits == -1 || bits > 120)
n = 4;
else if (src[14] || bits > 112)
n = 3;
else
n = 2;
n = decoct(src+12, n, tp, sizeof tmp - (tp - tmp));
if (n == 0) {
errno = EMSGSIZE;
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';
if (bits != -1)
tp += SPRINTF((tp, "/%u", bits));
/*
* Check for overflow, copy, and we're done.
*/
if ((size_t)(tp - tmp) > size) {
errno = EMSGSIZE;
return (NULL);
}
strcpy(dst, tmp);
return (dst);
}
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/*! \file */