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/*
* initialize subnet structure
* Copyright (C) 2000, 2002 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: initsubnet.c 3265 2007-10-08 19:52:55Z andreas $
*/
#include "internal.h"
#include "freeswan.h"
/*
- initsubnet - initialize ip_subnet from address and count
*
* The only hard part is checking for host-part bits turned on.
*/
err_t /* NULL for success, else string literal */
initsubnet(addr, count, clash, dst)
const ip_address *addr;
int count;
int clash; /* '0' zero host-part bits, 'x' die on them */
ip_subnet *dst;
{
unsigned char *p;
int n;
int c;
unsigned m;
int die;
dst->addr = *addr;
n = addrbytesptr(&dst->addr, (const unsigned char **)&p);
if (n == 0)
return "unknown address family";
switch (clash) {
case '0':
die = 0;
break;
case 'x':
die = 1;
break;
default:
return "unknown clash-control value in initsubnet";
break;
}
c = count / 8;
if (c > n)
return "impossible mask count";
p += c;
n -= c;
m = 0xff;
c = count % 8;
if (n > 0 && c != 0) /* partial byte */
m >>= c;
for (; n > 0; n--) {
if ((*p & m) != 0) {
if (die)
return "improper subnet, host-part bits on";
*p &= ~m;
}
m = 0xff;
p++;
}
dst->maskbits = count;
return NULL;
}
/*
- addrtosubnet - initialize ip_subnet from a single address
*/
err_t /* NULL for success, else string literal */
addrtosubnet(addr, dst)
const ip_address *addr;
ip_subnet *dst;
{
int n;
dst->addr = *addr;
n = addrbytesptr(&dst->addr, (const unsigned char **)NULL);
if (n == 0)
return "unknown address family";
dst->maskbits = n*8;
return NULL;
}
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