2 * Routines for G.723 dissection
3 * Copyright 2005, Anders Broman <anders.broman[at]ericsson.com>
7 * Wireshark - Network traffic analyzer
8 * By Gerald Combs <gerald@wireshark.org>
9 * Copyright 1998 Gerald Combs
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version 2
14 * of the License, or (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
38 #include <epan/packet.h>
39 #include <epan/rtp_pt.h>
42 /* Initialize the protocol and registered fields */
43 static int proto_g723 = -1;
44 static int hf_g723_frame_size_and_codec = -1;
45 static int hf_g723_lpc_B5_B0 = -1;
47 /* Initialize the subtree pointers */
48 static int ett_g723 = -1;
52 The least significant two bits of the first
53 octet in the frame determine the frame size and codec type:
54 bits content octets/frame
55 00 high-rate speech (6.3 kb/s) 24
56 01 low-rate speech (5.3 kb/s) 20
61 static const value_string g723_frame_size_and_codec_type_value[] = {
62 {0, "High-rate speech (6.3 kb/s)"},
63 {1, "Low-rate speech (5.3 kb/s)"}, /* Not coded */
70 /* Code to actually dissect the packets */
72 dissect_g723(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
77 /* Set up structures needed to add the protocol subtree and manage it */
79 proto_tree *g723_tree;
81 /* Make entries in Protocol column and Info column on summary display */
82 if (check_col(pinfo->cinfo, COL_PROTOCOL))
83 col_set_str(pinfo->cinfo, COL_PROTOCOL, "G.723.1");
85 ti = proto_tree_add_item(tree, proto_g723, tvb, 0, -1, FALSE);
87 g723_tree = proto_item_add_subtree(ti, ett_g723);
89 octet = tvb_get_guint8(tvb,offset);
90 proto_tree_add_item(g723_tree, hf_g723_frame_size_and_codec, tvb, offset, 1, FALSE);
91 proto_tree_add_item(g723_tree, hf_g723_lpc_B5_B0, tvb, offset, 1, FALSE);
93 if ((octet & 0x1) == 1 ) /* Low rate */
100 /* Register the protocol with Wireshark */
101 /* If this dissector uses sub-dissector registration add a registration routine.
102 This format is required because a script is used to find these routines and
103 create the code that calls these routines.
106 proto_reg_handoff_g723(void)
108 dissector_handle_t g723_handle;
110 g723_handle = create_dissector_handle(dissect_g723, proto_g723);
112 dissector_add("rtp.pt", PT_G723, g723_handle);
116 /* this format is require because a script is used to build the C function
117 that calls all the protocol registration.
121 proto_register_g723(void)
125 /* Setup list of header fields See Section 1.6.1 for details*/
126 static hf_register_info hf[] = {
127 { &hf_g723_frame_size_and_codec,
128 { "Frame size and codec type", "g723.frame_size_and_codec",
129 FT_UINT8, BASE_HEX, VALS(g723_frame_size_and_codec_type_value), 0x03,
130 "RATEFLAG_B0", HFILL }
132 { &hf_g723_lpc_B5_B0,
133 { "LPC_B5...LPC_B0", "g723.lpc.b5b0",
134 FT_UINT8, BASE_HEX, NULL, 0xfc,
140 /* Setup protocol subtree array */
141 static gint *ett[] = {
145 /* Register the protocol name and description */
146 proto_g723 = proto_register_protocol("G.723","G.723", "g723");
148 /* Required function calls to register the header fields and subtrees used */
149 proto_register_field_array(proto_g723, hf, array_length(hf));
150 proto_register_subtree_array(ett, array_length(ett));