wireshark/packet-rtp-events.c

/* packet-rtp-events.c
 *
 * Routines for RFC 2833 RTP Events dissection
 * Copyright 2003, Kevin A. Noll <knoll[AT]poss.com>
 *
 * $Id: packet-rtp-events.c,v 1.3 2003/11/27 21:20:46 guy Exp $
 *
 * Ethereal - Network traffic analyzer
 * By Gerald Combs <gerald@ethereal.com>
 * 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 RTP Events.
 */


#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <glib.h>
#include <epan/packet.h>
#include "prefs.h"

#include <stdio.h>
#include <string.h>
#include "packet-rtp-events.h"

/*  rtp_event_payload_type_value is the value used globally
	to set the appropriate payload type
    saved_pt_value is a temporary place to save the value
    	so we can properly reinitialize when the settings
    	get changed
*/
static guint rtp_event_payload_type_value = 101;
static guint saved_payload_type_value;


/* RTP Event Fields */

static int proto_rtp_events          = -1;

static int hf_rtp_events_event = -1; /* one byte */
static int hf_rtp_events_end = -1; /* one bit */
static int hf_rtp_events_reserved = -1; /* one bit */
static int hf_rtp_events_volume = -1; /* six bits */
static int hf_rtp_events_duration = -1; /* sixteen bits */


/* RTP Events fields defining a subtree */

static gint ett_rtp_events           = -1;

void
proto_reg_handoff_rtp_events(void);

static void
dissect_rtp_events( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
{
	proto_item *ti            = NULL;
	proto_tree *rtp_events_tree     = NULL;
	unsigned int offset       = 0;

	guint8      rtp_evt;
	guint8      octet;

	if ( check_col( pinfo->cinfo, COL_PROTOCOL ) )
	  {
	    col_set_str( pinfo->cinfo, COL_PROTOCOL, "RTP EVENT" );
	  }
	if (check_col(pinfo->cinfo, COL_INFO))
		col_clear(pinfo->cinfo, COL_INFO);


	/* Get event fields */

	rtp_evt = tvb_get_guint8(tvb, offset );

	if ( check_col( pinfo->cinfo, COL_INFO) )
	  {
		col_add_fstr( pinfo->cinfo, COL_INFO,
		    "Payload type=RTP Event, %s",
		    val_to_str( rtp_evt, rtp_event_type_values, "Unknown (%u)" ));


	  }

	if ( tree )
	  {
	    ti = proto_tree_add_item( tree, proto_rtp_events, tvb, offset, -1, FALSE );
	    rtp_events_tree = proto_item_add_subtree( ti, ett_rtp_events );

	    proto_tree_add_uint ( rtp_events_tree, hf_rtp_events_event, tvb, offset, 1, rtp_evt);

	    octet = tvb_get_guint8(tvb, offset +1 );
	    proto_tree_add_boolean (rtp_events_tree, hf_rtp_events_end, tvb, offset+1, 1, octet);
	    proto_tree_add_boolean (rtp_events_tree, hf_rtp_events_reserved, tvb, offset+1, 1, octet);
	    proto_tree_add_uint ( rtp_events_tree, hf_rtp_events_volume, tvb, offset+1, 1, octet);

	    proto_tree_add_item ( rtp_events_tree, hf_rtp_events_duration, tvb, offset+2, 2, FALSE);
	  }
}


void
proto_register_rtp_events(void)
{

	module_t *rtp_events_module;

	static hf_register_info hf[] =
	{
		{
			&hf_rtp_events_event,
			{
				"Event ID",
				"rtpevent.event_id",
				FT_UINT8,
				BASE_DEC,
				VALS(rtp_event_type_values),
				0x0,
				"", HFILL
			}
		},
		{
			&hf_rtp_events_end,
			{
				"End of Event",
				"rtpevent.end_of_event",
				FT_BOOLEAN,
				8,
				NULL,
				0x80,
				"", HFILL
			}
		},
		{
			&hf_rtp_events_reserved,
			{
				"Reserved",
				"rtpevent.reserved",
				FT_BOOLEAN,
				8,
				NULL,
				0x40,
				"", HFILL
			}
		},
		{
			&hf_rtp_events_volume,
			{
				"Volume",
				"rtpevent.volume",
				FT_UINT8,
				BASE_DEC,
				NULL,
				0x3F,
				"", HFILL
			}
		},

		{
			&hf_rtp_events_duration,
			{
				"Event Duration",
				"rtpevent.duration",
				FT_UINT16,
				BASE_DEC,
				NULL,
				0x0,
				"", HFILL
			}
		},

	};

	static gint *ett[] =
	{
		&ett_rtp_events,
	};


	proto_rtp_events = proto_register_protocol("RFC 2833 RTP Event", "RTP Event", "rtpevent");
	proto_register_field_array(proto_rtp_events, hf, array_length(hf));
	proto_register_subtree_array(ett, array_length(ett));


    /* Register preferences */
    rtp_events_module = prefs_register_protocol (proto_rtp_events, proto_reg_handoff_rtp_events);
    prefs_register_uint_preference (rtp_events_module,
                                    "event_payload_type_value", "Payload Type for RFC2833 RTP Events",
                                    "This is the value of the Payload Type field"
                                    "that specifies RTP Events", 10,
                                    &rtp_event_payload_type_value);
}



void
proto_reg_handoff_rtp_events(void)
{
	static dissector_handle_t rtp_events_handle;
	static int rtp_events_prefs_initialized = FALSE;

  	if (!rtp_events_prefs_initialized) {
		rtp_events_handle = create_dissector_handle(dissect_rtp_events, proto_rtp_events);
		rtp_events_prefs_initialized = TRUE;
	}
	else {
		dissector_delete("rtp.pt", saved_payload_type_value, rtp_events_handle);
	}

	saved_payload_type_value = rtp_event_payload_type_value;
	/* rtp_event_payload_type_value is set from preferences */

    	dissector_add("rtp.pt", saved_payload_type_value, rtp_events_handle);

}