96 lines
2.1 KiB
C
96 lines
2.1 KiB
C
/*
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* initialize subnet structure
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* Copyright (C) 2000, 2002 Henry Spencer.
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*
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* This library is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Library General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/lgpl.txt>.
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*
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* This library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
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* License for more details.
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*
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* RCSID $Id: initsubnet.c,v 1.1 2004/03/15 20:35:26 as Exp $
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*/
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#include "internal.h"
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#include "freeswan.h"
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/*
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- initsubnet - initialize ip_subnet from address and count
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*
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* The only hard part is checking for host-part bits turned on.
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*/
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err_t /* NULL for success, else string literal */
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initsubnet(addr, count, clash, dst)
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const ip_address *addr;
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int count;
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int clash; /* '0' zero host-part bits, 'x' die on them */
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ip_subnet *dst;
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{
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unsigned char *p;
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int n;
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int c;
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unsigned m;
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int die;
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dst->addr = *addr;
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n = addrbytesptr(&dst->addr, (const unsigned char **)&p);
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if (n == 0)
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return "unknown address family";
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switch (clash) {
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case '0':
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die = 0;
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break;
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case 'x':
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die = 1;
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break;
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default:
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return "unknown clash-control value in initsubnet";
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break;
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}
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c = count / 8;
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if (c > n)
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return "impossible mask count";
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p += c;
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n -= c;
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m = 0xff;
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c = count % 8;
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if (n > 0 && c != 0) /* partial byte */
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m >>= c;
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for (; n > 0; n--) {
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if ((*p & m) != 0) {
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if (die)
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return "improper subnet, host-part bits on";
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*p &= ~m;
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}
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m = 0xff;
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p++;
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}
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dst->maskbits = count;
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return NULL;
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}
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/*
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- addrtosubnet - initialize ip_subnet from a single address
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*/
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err_t /* NULL for success, else string literal */
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addrtosubnet(addr, dst)
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const ip_address *addr;
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ip_subnet *dst;
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{
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int n;
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dst->addr = *addr;
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n = addrbytesptr(&dst->addr, (const unsigned char **)NULL);
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if (n == 0)
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return "unknown address family";
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dst->maskbits = n*8;
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return NULL;
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}
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