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/*
* extract parts of an ip_subnet, and related
* Copyright (C) 2000 Henry Spencer.
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Library General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/lgpl.txt>.
*
* This library 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 Library General Public
* License for more details.
*
* RCSID $Id: subnettypeof.c,v 1.1 2004/03/15 20:35:26 as Exp $
*/
#include "internal.h"
#include "freeswan.h"
/*
- subnettypeof - get the address type of an ip_subnet
*/
int
subnettypeof(src)
const ip_subnet *src;
{
return src->addr.u.v4.sin_family;
}
/*
- networkof - get the network address of a subnet
*/
void
networkof(src, dst)
const ip_subnet *src;
ip_address *dst;
{
*dst = src->addr;
}
/*
- maskof - get the mask of a subnet, as an address
*/
void
maskof(src, dst)
const ip_subnet *src;
ip_address *dst;
{
int b;
unsigned char buf[16];
size_t n = addrlenof(&src->addr);
unsigned char *p;
if (src->maskbits > n*8 || n > sizeof(buf))
return; /* "can't happen" */
p = buf;
for (b = src->maskbits; b >= 8; b -= 8)
*p++ = 0xff;
if (b != 0)
*p++ = (0xff << (8 - b)) & 0xff;
while (p - buf < n)
*p++ = 0;
(void) initaddr(buf, n, addrtypeof(&src->addr), dst);
}
/*
- masktocount - convert a mask, expressed as an address, to a bit count
*/
int /* -1 if not valid mask */
masktocount(src)
const ip_address *src;
{
int b;
unsigned const char *bp;
size_t n;
unsigned const char *p;
unsigned const char *stop;
n = addrbytesptr(src, &bp);
if (n == 0)
return -1;
p = bp;
stop = bp + n;
n = 0;
while (p < stop && *p == 0xff) {
p++;
n += 8;
}
if (p < stop && *p != 0) { /* boundary in mid-byte */
b = *p++;
while (b&0x80) {
b <<= 1;
n++;
}
if ((b&0xff) != 0)
return -1; /* bits not contiguous */
}
while (p < stop && *p == 0)
p++;
if (p != stop)
return -1;
return n;
}
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