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/* packet-rtcdc.c
* Routines for the RTCWeb Data Channel Protocol dissection
* as specified in
* http://tools.ietf.org/html/draft-jesup-rtcweb-data-protocol-03
*
* Copyright 2012, Michael Tuexen <tuexen@wireshark.org>
*
* $Id$
*
* 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.
*/
#include "config.h"
#include <glib.h>
#include <epan/expert.h>
#include <epan/packet.h>
#include <epan/prefs.h>
void proto_reg_handoff_rtcdc(void);
/* PPID used for this protocol */
static guint32 rtcdc_ppid = 50;
/* Initialize the protocol and registered fields */
static int proto_rtcdc = -1;
static int hf_message_type = -1;
static int hf_channel_type = -1;
static int hf_flags = -1;
static int hf_flags_reserved = -1;
static int hf_unordered_allowed = -1;
static int hf_reliability = -1;
static int hf_priority = -1;
static int hf_label = -1;
static int hf_error = -1;
static int hf_sid = -1;
/* Initialize the subtree pointers */
static gint ett_rtcdc = -1;
static gint ett_flags = -1;
#define DATA_CHANNEL_OPEN_REQUEST 0x00
#define DATA_CHANNEL_OPEN_RESPONSE 0x01
#define DATA_CHANNEL_ACK 0x02
static const value_string message_type_values[] = {
{ DATA_CHANNEL_OPEN_REQUEST, "DATA_CHANNEL_OPEN_REQUEST" },
{ DATA_CHANNEL_OPEN_RESPONSE, "DATA_CHANNEL_OPEN_RESPONSE" },
{ DATA_CHANNEL_ACK, "DATA_CHANNEL_ACK" },
{ 0, NULL }
};
#define DATA_CHANNEL_RELIABLE 0x00
#define DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT 0x01
#define DATA_CHANNEL_PARTIAL_RELIABLE_TIMED 0x02
static const value_string channel_type_values[] = {
{ DATA_CHANNEL_RELIABLE, "DATA_CHANNEL_RELIABLE" },
{ DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT, "DATA_CHANNEL_PARTIAL_RELIABLE_REXMIT" },
{ DATA_CHANNEL_PARTIAL_RELIABLE_TIMED, "DATA_CHANNEL_PARTIAL_RELIABLE_TIMED" },
{ 0, NULL }
};
#define MESSAGE_TYPE_LENGTH 1
#define CHANNEL_TYPE_LENGTH 1
#define FLAGS_LENGTH 2
#define RELIABILITY_LENGTH 2
#define PRIORITY_LENGTH 2
#define MESSAGE_TYPE_OFFSET 0
#define CHANNEL_TYPE_OFFSET (MESSAGE_TYPE_OFFSET + MESSAGE_TYPE_LENGTH)
#define FLAGS_OFFSET (CHANNEL_TYPE_OFFSET + CHANNEL_TYPE_LENGTH)
#define RELIABILITY_OFFSET (FLAGS_OFFSET + FLAGS_LENGTH)
#define PRIORITY_OFFSET (RELIABILITY_OFFSET + RELIABILITY_LENGTH)
#define LABEL_OFFSET (PRIORITY_OFFSET + PRIORITY_LENGTH)
#define DATA_CHANNEL_FLAG_OUT_OF_ORDER_ALLOWED_MASK 0x0001
#define DATA_CHANNEL_FLAG_RESERVED_MASK 0xFFFE
static void
dissect_open_request_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *rtcdc_tree, proto_item *rtcdc_item _U_) {
if (rtcdc_tree) {
proto_tree *flags_tree;
proto_item *flags_item;
proto_tree_add_item(rtcdc_tree, hf_channel_type, tvb, CHANNEL_TYPE_OFFSET, CHANNEL_TYPE_LENGTH, ENC_BIG_ENDIAN);
flags_item = proto_tree_add_item(rtcdc_tree, hf_flags, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN);
flags_tree = proto_item_add_subtree(flags_item, ett_flags);
proto_tree_add_item(flags_tree, hf_flags_reserved, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(flags_tree, hf_unordered_allowed, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_reliability, tvb, RELIABILITY_OFFSET, RELIABILITY_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_priority, tvb, PRIORITY_OFFSET, PRIORITY_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_label, tvb, LABEL_OFFSET, -1, ENC_BIG_ENDIAN);
}
return;
}
#define ERROR_LENGTH 1
#define SID_LENGTH 2
#define DATA_CHANNEL_RESPONSE_LENGTH (MESSAGE_TYPE_LENGTH + ERROR_LENGTH + FLAGS_LENGTH + SID_LENGTH)
#define ERROR_OFFSET (MESSAGE_TYPE_OFFSET + MESSAGE_TYPE_LENGTH)
#define SID_OFFSET (FLAGS_OFFSET + FLAGS_LENGTH)
static void
dissect_open_response_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *rtcdc_tree, proto_item *rtcdc_item) {
if (tvb_length(tvb) > DATA_CHANNEL_RESPONSE_LENGTH) {
expert_add_info_format(pinfo, rtcdc_item, PI_MALFORMED, PI_ERROR, "Message too long");
}
if (rtcdc_tree) {
proto_tree_add_item(rtcdc_tree, hf_error, tvb, ERROR_OFFSET, ERROR_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_flags, tvb, FLAGS_OFFSET, FLAGS_LENGTH, ENC_BIG_ENDIAN);
proto_tree_add_item(rtcdc_tree, hf_sid, tvb, SID_OFFSET, SID_LENGTH, ENC_BIG_ENDIAN);
}
return;
}
#define DATA_CHANNEL_ACK_LENGTH MESSAGE_TYPE_LENGTH
static void
dissect_open_ack_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *rtcdc_tree _U_, proto_item *rtcdc_item) {
if (tvb_length(tvb) > DATA_CHANNEL_ACK_LENGTH) {
expert_add_info_format(pinfo, rtcdc_item, PI_MALFORMED, PI_ERROR, "Message too long");
}
return;
}
static int
dissect_rtcdc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
proto_item *rtcdc_item;
proto_tree *rtcdc_tree;
guint8 message_type;
message_type = tvb_get_guint8(tvb, MESSAGE_TYPE_OFFSET);
col_set_str(pinfo->cinfo, COL_PROTOCOL, "RTCDC");
col_add_fstr(pinfo->cinfo, COL_INFO, "%s ", val_to_str_const(message_type, message_type_values, "reserved"));
if (tree) {
rtcdc_item = proto_tree_add_item(tree, proto_rtcdc, tvb, 0, -1, ENC_NA);
rtcdc_tree = proto_item_add_subtree(rtcdc_item, ett_rtcdc);
proto_tree_add_item(rtcdc_tree, hf_message_type, tvb, MESSAGE_TYPE_OFFSET, MESSAGE_TYPE_LENGTH, ENC_BIG_ENDIAN);
} else {
rtcdc_item = NULL;
rtcdc_tree = NULL;
}
switch (message_type) {
case DATA_CHANNEL_OPEN_REQUEST:
dissect_open_request_message(tvb, pinfo, rtcdc_tree, rtcdc_item);
break;
case DATA_CHANNEL_OPEN_RESPONSE:
dissect_open_response_message(tvb, pinfo, rtcdc_tree, rtcdc_item);
break;
case DATA_CHANNEL_ACK:
dissect_open_ack_message(tvb, pinfo, rtcdc_tree, rtcdc_item);
break;
default:
expert_add_info_format(pinfo, rtcdc_item, PI_MALFORMED, PI_ERROR, "Unknown message type");
break;
}
return tvb_length(tvb);
}
void
proto_register_rtcdc(void)
{
module_t *rtcdc_module;
static hf_register_info hf[] = {
{ &hf_message_type, { "Message type", "rtcdc.message_type", FT_UINT8, BASE_DEC, VALS(message_type_values), 0x0, NULL, HFILL } },
{ &hf_channel_type, { "Channel type", "rtcdc.channel_type", FT_UINT8, BASE_DEC, VALS(channel_type_values), 0x0, NULL, HFILL } },
{ &hf_flags, { "Flags", "rtcdc.flags", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL } },
{ &hf_flags_reserved, { "Reserved", "rtcdc.flags_reserved", FT_UINT16, BASE_HEX, NULL, DATA_CHANNEL_FLAG_RESERVED_MASK, NULL, HFILL } },
{ &hf_unordered_allowed, { "Unordered allowed", "rtcdc.flags_unordered_allowed", FT_BOOLEAN, 16, NULL, DATA_CHANNEL_FLAG_OUT_OF_ORDER_ALLOWED_MASK, NULL, HFILL } },
{ &hf_reliability, { "Reliability parameter", "rtcdc.reliability_parameter", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } },
{ &hf_priority, { "Priority", "rtcdc.priority", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } },
{ &hf_label, { "Label", "rtcdc.label", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL } },
{ &hf_error, { "Error", "rtcdc.error", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } },
{ &hf_sid, { "Reverse stream identifier", "rtcdc.reverse_stream_id", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }
};
static gint *ett[] = {
&ett_rtcdc,
&ett_flags
};
proto_rtcdc = proto_register_protocol("WebRTC Datachannel Protocol", "RTCDC", "rtcdc");
proto_register_field_array(proto_rtcdc, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
rtcdc_module = prefs_register_protocol(proto_rtcdc, proto_reg_handoff_rtcdc);
prefs_register_uint_preference(rtcdc_module, "sctp.ppi", "RTCDC SCTP PPID", "RTCDC SCTP PPID if other than the default", 10, &rtcdc_ppid);
}
void
proto_reg_handoff_rtcdc(void)
{
static gboolean initialized = FALSE;
static dissector_handle_t rtcdc_handle;
static guint32 current_ppid;
if (!initialized) {
rtcdc_handle = new_create_dissector_handle(dissect_rtcdc, proto_rtcdc);
initialized = TRUE;
} else {
dissector_delete_uint("sctp.ppi", current_ppid, rtcdc_handle);
}
current_ppid = rtcdc_ppid;
dissector_add_uint("sctp.ppi", current_ppid, rtcdc_handle);
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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