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/****************************************************************************
** File: chap.c
**
** Author: Mike Borella
**
** Comments: CHAP decoding.
**
** $Id: chap.c,v 1.8 2001/10/02 18:37:43 mborella Exp $
**
** 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.
**
** 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 Library General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
*****************************************************************************/
#include "chap.h"
/*
* CHAP header
*/
typedef struct chap
{
u_int8_t code;
u_int8_t identifier;
u_int16_t length;
} chap_t;
/*
* CHAP codes
*/
#define CHAP_CODE_CHALLENGE 1
#define CHAP_CODE_RESPONSE 2
#define CHAP_CODE_SUCCESS 3
#define CHAP_CODE_FAILURE 4
/*
* CHAP code map
*/
strmap_t chap_code_map[] =
{
{ CHAP_CODE_CHALLENGE, "challenge" },
{ CHAP_CODE_RESPONSE, "response" },
{ CHAP_CODE_SUCCESS, "success" },
{ CHAP_CODE_FAILURE, "failure" },
{ 0, "" }
};
extern struct arg_t * my_args;
/*----------------------------------------------------------------------------
**
** dump_chap()
**
** Dump CHAP headers and payload.
**
**----------------------------------------------------------------------------
*/
void dump_chap(packet_t *pkt)
{
chap_t chap;
/* Set the layer */
set_layer(LAYER_DATALINK);
/*
* Get the header
*/
if (get_packet_bytes((u_int8_t *) &chap, pkt, sizeof(chap_t)) == 0)
return;
/*
* Conversion
*/
chap.length = ntohs(chap.length);
/*
* Dump the header
*/
if (my_args->m)
{
display_minimal_string("| CHAP ");
}
else
{
display_header_banner("CHAP Header");
display_strmap("Code", chap.code, chap_code_map);
display("Identifier", &chap.identifier, 1, DISP_DEC);
display("Length", (u_int8_t *) &chap.length, 2, DISP_DEC);
}
/*
* Get the CHAP payload
*/
switch(chap.code)
{
case CHAP_CODE_CHALLENGE:
case CHAP_CODE_RESPONSE:
{
u_int8_t * value;
u_int8_t value_size;
u_int8_t * name;
u_int16_t name_size;
/* Get the value size */
if (get_packet_bytes(&value_size, pkt, 1) == 0)
return;
/* Get the value */
value = (u_int8_t *) my_malloc(value_size);
if (get_packet_bytes(value, pkt, value_size) == 0)
{
my_free(value);
return;
}
/* Figure out the size of the name and get it */
name_size = chap.length - sizeof(chap_t) - value_size - 1;
name = (u_int8_t *) my_malloc(name_size+1);
if (get_packet_bytes(name, pkt, name_size) == 0)
{
my_free(value);
my_free(name);
return;
}
name[name_size] = '\0';
/* display everything */
if (my_args->m)
{
if (chap.code == CHAP_CODE_CHALLENGE)
display_minimal_string("challenge ");
if (chap.code == CHAP_CODE_RESPONSE)
display_minimal_string("response ");
display_minimal_string("(");
display_minimal(value, value_size, DISP_HEX);
display_minimal_string(", ");
display_minimal_string(name);
display_minimal_string(")");
}
else
{
display("Value size", &value_size, 1, DISP_DEC);
display("Value", value, value_size, DISP_HEX_MULTILINE);
display_string("Name", name);
}
/* free memory */
my_free(value);
my_free(name);
}
break;
case CHAP_CODE_SUCCESS:
case CHAP_CODE_FAILURE:
{
u_int8_t * message;
u_int8_t message_len;
/* figure out length of the message and then grab it */
message_len = chap.length - sizeof(chap_t);
message = (u_int8_t *) my_malloc (message_len + 1);
if (get_packet_bytes(message, pkt, message_len) == 0)
{
my_free(message);
return;
}
message[message_len] = '\0';
/* display it */
if (my_args->m)
{
if (chap.code == CHAP_CODE_SUCCESS)
display_minimal_string("success ");
if (chap.code == CHAP_CODE_FAILURE)
display_minimal_string("failure ");
display_minimal_string("(");
display_minimal_string(message);
display_minimal_string(")");
}
else
{
display_string("Message", message);
}
/* free memory */
my_free(message);
}
break;
}
}
|
