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/* packet-g723.c
* Routines for G.723 dissection
* Copyright 2005, Anders Broman <anders.broman[at]ericsson.com>
*
* $Id$
*
* 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.
*
* References:
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <glib.h>
#include <epan/packet.h>
#include <epan/rtp_pt.h>
/* Initialize the protocol and registered fields */
static int proto_g723 = -1;
static int hf_g723_frame_size_and_codec = -1;
static int hf_g723_lpc_B5_B0 = -1;
/* Initialize the subtree pointers */
static int ett_g723 = -1;
/* RFC 3551
The least significant two bits of the first
octet in the frame determine the frame size and codec type:
bits content octets/frame
00 high-rate speech (6.3 kb/s) 24
01 low-rate speech (5.3 kb/s) 20
10 SID frame 4
11 reserved
*/
static const value_string g723_frame_size_and_codec_type_value[] = {
{0, "High-rate speech (6.3 kb/s)"},
{1, "Low-rate speech (5.3 kb/s)"}, /* Not coded */
{2, "SID frame"},
{3, "Reserved"},
{ 0, NULL }
};
/* Code to actually dissect the packets */
static void
dissect_g723(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
int offset = 0;
guint octet;
/* Set up structures needed to add the protocol subtree and manage it */
proto_item *ti;
proto_tree *g723_tree;
/* Make entries in Protocol column and Info column on summary display */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "G.723.1");
if (tree) {
ti = proto_tree_add_item(tree, proto_g723, tvb, 0, -1, ENC_NA);
g723_tree = proto_item_add_subtree(ti, ett_g723);
octet = tvb_get_guint8(tvb,offset);
proto_tree_add_item(g723_tree, hf_g723_frame_size_and_codec, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(g723_tree, hf_g723_lpc_B5_B0, tvb, offset, 1, ENC_BIG_ENDIAN);
if ((octet & 0x1) == 1 ) /* Low rate */
return;
}/* if tree */
}
/* Register the protocol with Wireshark */
/* If this dissector uses sub-dissector registration add a registration routine.
This format is required because a script is used to find these routines and
create the code that calls these routines.
*/
void
proto_reg_handoff_g723(void)
{
dissector_handle_t g723_handle;
g723_handle = create_dissector_handle(dissect_g723, proto_g723);
dissector_add_uint("rtp.pt", PT_G723, g723_handle);
}
/* this format is require because a script is used to build the C function
that calls all the protocol registration.
*/
void
proto_register_g723(void)
{
/* Setup list of header fields See Section 1.6.1 for details*/
static hf_register_info hf[] = {
{ &hf_g723_frame_size_and_codec,
{ "Frame size and codec type", "g723.frame_size_and_codec",
FT_UINT8, BASE_HEX, VALS(g723_frame_size_and_codec_type_value), 0x03,
"RATEFLAG_B0", HFILL }
},
{ &hf_g723_lpc_B5_B0,
{ "LPC_B5...LPC_B0", "g723.lpc.b5b0",
FT_UINT8, BASE_HEX, NULL, 0xfc,
NULL, HFILL }
},
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_g723,
};
/* Register the protocol name and description */
proto_g723 = proto_register_protocol("G.723","G.723", "g723");
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_g723, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
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