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/* $OpenBSD: scheme.c,v 1.6 2002/06/09 08:13:08 todd Exp $ */
/*
* Copyright 1997-2000 Niels Provos <provos@citi.umich.edu>
* 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[] = "$OpenBSD: scheme.c,v 1.6 2002/06/09 08:13:08 todd 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 "log.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_print("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_print("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_print("Unknown scheme in scheme_get_ref()");
return 0;
}
}
size_t
varpre2octets(u_int8_t *varpre)
{
int blocks, header;
size_t size;
/* XXX - only support a few octets at the moment */
if(varpre[0] == 255 && varpre[1] == 255)
return (0);
size = 0;
if (varpre[0] == 255) {
blocks = 3;
varpre++;
size = 65280;
header = 4;
} else {
header = 2;
blocks = 2;
}
while (blocks--) {
size = (size << 8) + *varpre;
varpre++;
}
size = (size + 7) / 8;
return (size + header);
}
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