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/* packet-turnchannel.c
* Routines for TURN channel dissection (TURN negociation is handled
* in the STUN2 dissector
* Copyright 2008, 8x8 Inc. <petithug@8x8.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please refer to the following specs for protocol detail:
* - draft-ietf-behave-rfc3489bis-15
* - draft-ietf-mmusic-ice-19
* - draft-ietf-behave-nat-behavior-discovery-03
* - draft-ietf-behave-turn-07
* - draft-ietf-behave-turn-ipv6-03
*/
#include "config.h"
#include <epan/packet.h>
#include "packet-tcp.h"
void proto_register_turnchannel(void);
void proto_reg_handoff_turnchannel(void);
/* heuristic subdissectors */
static heur_dissector_list_t heur_subdissector_list;
/* Initialize the protocol and registered fields */
static int proto_turnchannel = -1;
static int hf_turnchannel_id = -1;
static int hf_turnchannel_len = -1;
#define TURNCHANNEL_HDR_LEN ((guint)4)
/* Initialize the subtree pointers */
static gint ett_turnchannel = -1;
static int
dissect_turnchannel_message(tvbuff_t *tvb, packet_info *pinfo,
proto_tree *tree, void *data _U_)
{
guint len;
guint16 channel_id;
guint16 data_len;
proto_item *ti;
proto_tree *turnchannel_tree;
heur_dtbl_entry_t *hdtbl_entry;
len = tvb_captured_length(tvb);
/* First, make sure we have enough data to do the check. */
if (len < TURNCHANNEL_HDR_LEN) {
return 0;
}
channel_id = tvb_get_ntohs(tvb, 0);
data_len = tvb_get_ntohs(tvb, 2);
if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
return 0;
}
if (len != TURNCHANNEL_HDR_LEN + data_len) {
return 0;
}
/* Seems to be a decent TURN channel message */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "TURN CHANNEL");
col_add_fstr(pinfo->cinfo, COL_INFO, "Channel Id 0x%x", channel_id);
ti = proto_tree_add_item(tree, proto_turnchannel, tvb, 0, -1, ENC_NA);
turnchannel_tree = proto_item_add_subtree(ti, ett_turnchannel);
proto_tree_add_uint(turnchannel_tree, hf_turnchannel_id, tvb, 0, 2, channel_id);
proto_tree_add_uint(turnchannel_tree, hf_turnchannel_len, tvb, 2, 2, data_len);
if (len > TURNCHANNEL_HDR_LEN) {
tvbuff_t *next_tvb;
guint reported_len, new_len;
new_len = tvb_captured_length_remaining(tvb, TURNCHANNEL_HDR_LEN);
reported_len = tvb_reported_length_remaining(tvb,
TURNCHANNEL_HDR_LEN);
if (data_len < reported_len) {
reported_len = data_len;
}
next_tvb = tvb_new_subset(tvb, TURNCHANNEL_HDR_LEN, new_len,
reported_len);
if (!dissector_try_heuristic(heur_subdissector_list,
next_tvb, pinfo, tree, &hdtbl_entry, NULL)) {
call_data_dissector(next_tvb, pinfo, tree);
}
}
return tvb_captured_length(tvb);
}
static guint
get_turnchannel_message_len(packet_info *pinfo _U_, tvbuff_t *tvb,
int offset, void *data _U_)
{
return (guint)tvb_get_ntohs(tvb, offset+2) + TURNCHANNEL_HDR_LEN;
}
static int
dissect_turnchannel_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
tcp_dissect_pdus(tvb, pinfo, tree, TRUE, TURNCHANNEL_HDR_LEN,
get_turnchannel_message_len, dissect_turnchannel_message, data);
return tvb_captured_length(tvb);
}
static gboolean
dissect_turnchannel_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
guint len;
guint16 channel_id;
guint16 data_len;
len = tvb_captured_length(tvb);
/* First, make sure we have enough data to do the check. */
if (len < TURNCHANNEL_HDR_LEN) {
return FALSE;
}
channel_id = tvb_get_ntohs(tvb, 0);
data_len = tvb_get_ntohs(tvb, 2);
if ((channel_id < 0x4000) || (channel_id > 0xFFFE)) {
return FALSE;
}
if (len != TURNCHANNEL_HDR_LEN + data_len) {
return FALSE;
}
return dissect_turnchannel_message(tvb, pinfo, tree, NULL);
}
void
proto_register_turnchannel(void)
{
static hf_register_info hf[] = {
{ &hf_turnchannel_id,
{ "TURN Channel ID", "turnchannel.id", FT_UINT16,
BASE_HEX, NULL, 0x0, NULL, HFILL }
},
{ &hf_turnchannel_len,
{ "Data Length", "turnchannel.length", FT_UINT16,
BASE_DEC, NULL, 0x0, NULL, HFILL }
},
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_turnchannel,
};
/* Register the protocol name and description */
proto_turnchannel = proto_register_protocol("TURN Channel",
"TURNCHANNEL", "turnchannel");
register_dissector("turnchannel", dissect_turnchannel_message,
proto_turnchannel);
/* subdissectors */
heur_subdissector_list = register_heur_dissector_list("turnchannel", proto_turnchannel);
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_turnchannel, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_turnchannel(void)
{
dissector_handle_t turnchannel_tcp_handle;
dissector_handle_t turnchannel_udp_handle;
turnchannel_tcp_handle = create_dissector_handle(dissect_turnchannel_tcp, proto_turnchannel);
turnchannel_udp_handle = find_dissector("turnchannel");
/* Register for "Decode As" in case STUN negotiation isn't captured */
dissector_add_for_decode_as("tcp.port", turnchannel_tcp_handle);
dissector_add_for_decode_as("udp.port", turnchannel_udp_handle);
/* TURN negotiation is handled through STUN2 dissector (packet-stun.c),
so only it should be able to determine if a packet is a TURN packet */
heur_dissector_add("stun", dissect_turnchannel_heur, "TURN Channel over STUN", "turnchannel_stun", proto_turnchannel, HEURISTIC_ENABLE);
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
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