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/*
* Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Niels Provos.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* scheme.c:
* SCHEME handling functions
*/
#ifndef lint
static char rcsid[] = "$Id: scheme.c,v 1.1 1998/11/14 23:37:28 deraadt Exp $";
#endif
#define _SCHEME_C_
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "config.h"
#include "attributes.h"
#include "buffer.h"
#include "scheme.h"
#include "errlog.h"
u_int8_t *
scheme_get_gen(u_int8_t *scheme)
{
int header;
switch(ntohs(*(u_int16_t *)scheme)) {
case DH_G_2_MD5:
case DH_G_3_MD5:
case DH_G_2_DES_MD5:
case DH_G_5_MD5:
case DH_G_3_DES_MD5:
case DH_G_2_3DES_SHA1:
case DH_G_5_DES_MD5:
case DH_G_3_3DES_SHA1:
case DH_G_5_3DES_SHA1:
return NULL;
case DH_G_VAR_MD5:
case DH_G_VAR_DES_MD5:
case DH_G_VAR_3DES_SHA1:
if (scheme[2] == 255 && scheme[3] == 255)
header = 8;
else if (scheme[2] == 255)
header = 4;
else
header = 2;
return scheme+2+header;
default:
log_error(0, "Unknown scheme in scheme_get_gen()");
return NULL;
}
}
u_int8_t *
scheme_get_mod(u_int8_t *scheme)
{
int header;
switch(ntohs(*(u_int16_t *)scheme)) {
case DH_G_2_MD5:
case DH_G_3_MD5:
case DH_G_2_DES_MD5:
case DH_G_5_MD5:
case DH_G_3_DES_MD5:
case DH_G_2_3DES_SHA1:
case DH_G_5_DES_MD5:
case DH_G_3_3DES_SHA1:
case DH_G_5_3DES_SHA1:
return scheme+2;
break;
case DH_G_VAR_MD5:
case DH_G_VAR_DES_MD5:
case DH_G_VAR_3DES_SHA1:
if (scheme[2] == 255 && scheme[3] == 255)
header = 8;
else if (scheme[2] == 255)
header = 4;
else
header = 2;
if (varpre2octets(scheme+2) > 2)
return scheme+2+header+varpre2octets(scheme+2+header);
else
return scheme+2;
break;
default:
log_error(0, "Unknown scheme in scheme_get_mod()");
return NULL;
}
}
size_t
scheme_get_len(u_int8_t *scheme)
{
return 2 + varpre2octets(scheme+2);
}
u_int16_t
scheme_get_ref(u_int8_t *scheme)
{
switch(ntohs(*(u_int16_t *)scheme)) {
case DH_G_2_MD5:
case DH_G_2_DES_MD5:
case DH_G_2_3DES_SHA1:
return DH_G_2_MD5;
case DH_G_3_MD5:
case DH_G_3_DES_MD5:
case DH_G_3_3DES_SHA1:
return DH_G_3_MD5;
case DH_G_5_MD5:
case DH_G_5_DES_MD5:
case DH_G_5_3DES_SHA1:
return DH_G_5_MD5;
case DH_G_VAR_MD5:
case DH_G_VAR_DES_MD5:
case DH_G_VAR_3DES_SHA1:
return DH_G_VAR_MD5;
default:
log_error(0, "Unknown scheme in scheme_get_ref()");
return 0;
}
}
size_t
varpre2octets(u_int8_t *varpre)
{
int blocks, header;
size_t size;
mpz_t offset, a;
mpz_init(offset);
mpz_init(a);
/* XXX - only support a few octets at the moment */
if(*varpre == 255 && *(varpre+1) == 255) {
blocks = 6;
varpre += 2;
mpz_set_ui(offset, 16776960);
header = 8;
} else if (*varpre == 255) {
blocks = 3;
varpre++;
mpz_set_ui(offset, 65280);
header = 4;
} else {
header = 2;
blocks = 2;
}
while(blocks--) {
mpz_mul_ui(a, a, 256);
mpz_add_ui(a, a, *varpre);
varpre++;
}
mpz_add(offset, offset, a);
mpz_cdiv_q_ui(offset, offset, 8);
size = mpz_get_ui(offset) + header;
mpz_clear(offset);
mpz_clear(a);
return size;
}
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