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/* packet-tpkt.c
*
* Routines for TPKT dissection
* Copyright 2000, Philips Electronics N.V.
* Andreas Sikkema <andreas.sikkema@philips.com>
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.org>
* Copyright 1998 Gerald Combs
*
*
* 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 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.
*/
/*
* This dissector tries to dissect the TPKT protocol according to
* RFC 1006
*
* IMPORTANT IMPORTANT IMPORTANT IMPORTANT IMPORTANT IMPORTANT IMPORTANT
*
* Please examine the dissector. It is NOT defined in the normal way!
* Some variables are references and the dissector also returns a
* value! And no, this is not a heuristic dissector!
*
* IMPORTANT IMPORTANT IMPORTANT IMPORTANT IMPORTANT IMPORTANT IMPORTANT
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <glib.h>
#include "packet.h"
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#include <stdio.h>
#include <string.h>
#include "packet-tpkt.h"
/* TPKT header fields */
static int proto_tpkt = -1;
static int hf_tpkt_version = -1;
static int hf_tpkt_reserved = -1;
static int hf_tpkt_length = -1;
/* TPKT fields defining a sub tree */
static gint ett_tpkt = -1;
int
is_tpkt( tvbuff_t *tvb, unsigned int* offset )
{
if ( (*offset) + 4 > tvb_length( tvb ) ) return FALSE;
if ( ! ( ( tvb_get_guint8( tvb, ( *offset ) ) == 3 ) &&
( tvb_get_guint8( tvb, ( *offset ) + 1 ) == 0 ) ) ) return FALSE;
return TRUE;
}
int
dissect_tpkt( tvbuff_t *tvb, unsigned int* offset, packet_info *pinfo, proto_tree *tree )
{
proto_item *ti = NULL;
proto_tree *tpkt_tree = NULL;
unsigned int data_len = 0;
pinfo->current_proto = "TPKT";
/* There should at least be 4 bytes left in the frame */
if ( (*offset) + 4 > tvb_length( tvb ) ) return -1;
/*
* The first octet should be 3 and the second one should be 0
* The H.323 implementers guide suggests that this migh not
* always be the case....
*/
if ( ! ( ( tvb_get_guint8( tvb, ( *offset ) ) == 3 ) &&
( tvb_get_guint8( tvb, ( *offset ) + 1 ) == 0 ) ) ) return -1;
if ( check_col( pinfo->fd, COL_PROTOCOL ) ) {
col_set_str( pinfo->fd, COL_PROTOCOL, "TPKT" );
}
if ( check_col( pinfo->fd, COL_INFO) ) {
/*data_len = pntohs( &pd[ (*offset) + 2 ] );*/
data_len = tvb_get_ntohs( tvb, (*offset) + 2 );
col_add_fstr( pinfo->fd, COL_INFO, "TPKT Data length = %d", data_len );
}
if ( tree ) {
ti = proto_tree_add_item( tree, proto_tpkt, tvb, (*offset), 4, FALSE );
tpkt_tree = proto_item_add_subtree( ti, ett_tpkt );
/* Version 1st octet */
proto_tree_add_item( tpkt_tree, hf_tpkt_version, tvb, (*offset), 1, FALSE );
(*offset)++;
/* Reserved octet*/
proto_tree_add_item( tpkt_tree, hf_tpkt_reserved, tvb, (*offset), 1, FALSE );
(*offset)++;
}
else {
(*offset) += 2;
}
/* Length, two octets */
/*data_len = pntohs( &pd[ (*offset) ] );*/
data_len = tvb_get_ntohs( tvb, (*offset) );
if ( tree )
proto_tree_add_uint_format( tpkt_tree, hf_tpkt_length, tvb, (*offset), 2, data_len, "Length: %d", data_len );
(*offset) += 2;
return data_len;
}
void
proto_register_tpkt(void)
{
static hf_register_info hf[] =
{
{
&hf_tpkt_version,
{
"Version",
"tpkt.version",
FT_UINT8,
BASE_DEC,
NULL,
0x0,
""
}
},
{
&hf_tpkt_reserved,
{
"Reserved",
"tpkt.reserved",
FT_UINT8,
BASE_DEC,
NULL,
0x0,
""
}
},
{
&hf_tpkt_length,
{
"Length",
"tpkt.length",
FT_UINT16,
BASE_DEC,
NULL,
0x0,
""
}
},
};
static gint *ett[] =
{
&ett_tpkt,
};
proto_tpkt = proto_register_protocol("TPKT", "TPKT", "tpkt");
proto_register_field_array(proto_tpkt, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
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