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/* cookie generation/verification routines.
* Copyright (C) 1997 Angelos D. Keromytis.
* Copyright (C) 1998-2002 D. Hugh Redelmeier.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU 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/gpl.txt>.
*
* This program 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 General Public License
* for more details.
*
* RCSID $Id: cookie.c,v 1.17 2002/04/24 07:35:46 mcr Exp $
*/
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <freeswan.h>
#include "constants.h"
#include "defs.h"
#include "sha1.h"
#include "rnd.h"
#include "cookie.h"
const u_char zero_cookie[COOKIE_SIZE]; /* guaranteed 0 */
/* Generate a cookie.
* First argument is true if we're to create an Initiator cookie.
* Length SHOULD be a multiple of sizeof(u_int32_t).
*/
void
get_cookie(bool initiator, u_int8_t *cookie, int length, const ip_address *addr)
{
u_char buffer[SHA1_DIGEST_SIZE];
SHA1_CTX ctx;
do {
if (initiator)
{
get_rnd_bytes(cookie, length);
}
else /* Responder cookie */
{
/* This looks as good as any way */
size_t addr_length;
static u_int32_t counter = 0;
unsigned char addr_buff[
sizeof(union {struct in_addr; struct in6_addr;})];
addr_length = addrbytesof(addr, addr_buff, sizeof(addr_buff));
SHA1Init(&ctx);
SHA1Update(&ctx, addr_buff, addr_length);
SHA1Update(&ctx, secret_of_the_day, sizeof(secret_of_the_day));
counter++;
SHA1Update(&ctx, (const void *) &counter, sizeof(counter));
SHA1Final(buffer, &ctx);
memcpy(cookie, buffer, length);
}
} while (is_zero_cookie(cookie)); /* probably never loops */
}
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