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/* packet-amr.c
* Routines for AMR dissection
* Copyright 2005, Anders Broman <anders.broman[at]ericsson.com>
*
* $Id$
*
* 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.
*
* References:
* RFC 3267
* http://www.ietf.org/rfc/rfc3267.txt?number=3267
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <glib.h>
#ifdef NEED_SNPRINTF_H
# include "snprintf.h"
#endif
#include <epan/packet.h>
#include "prefs.h"
/* Initialize the protocol and registered fields */
static int proto_amr = -1;
static int hf_amr_cmr = -1;
static int hf_amr_reserved = -1;
static int hf_amr_toc_f = -1;
static int hf_amr_toc_ft = -1;
static int hf_amr_toc_q = -1;
/* Initialize the subtree pointers */
static int ett_amr = -1;
static int ett_amr_toc = -1;
/* The dynamic payload type which will be dissected as AMR */
static guint dynamic_payload_type = 0;
static guint temp_dynamic_payload_type = 0;
/* Currently only octet aligned works */
static gboolean octet_aligned = TRUE;
static const value_string amr_codec_mode_request_vals[] = {
{0, "AMR 4,75 kbit/s"},
{1, "AMR 5,15 kbit/s"},
{2, "AMR 5,90 kbit/s"},
{3, "AMR 6,70 kbit/s (PDC-EFR)"},
{4, "AMR 7,40 kbit/s (TDMA-EFR)"},
{5, "AMR 7,95 kbit/s"},
{6, "AMR 10,2 kbit/s"},
{7, "AMR 12,2 kbit/s (GSM-EFR)"},
{8, "AMR SID"},
{9, "GSM-EFR SID"},
{10, "TDMA-EFR SID"},
{11, "PDC-EFR SID"},
/*
{12-14 - - For future use
*/
{15, "No Data (No transmission/No reception)"},
{ 0, NULL }
};
static const true_false_string toc_f_bit_vals = {
"Followed by another speech frame",
"Last frame in this payload"
};
static const true_false_string toc_q_bit_vals = {
"Ok",
"Severely damaged frame"
};
/* Code to actually dissect the packets */
static void
dissect_amr(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
int offset = 0;
int toc_offset = 0;
guint octet;
/* Set up structures needed to add the protocol subtree and manage it */
proto_item *ti,*toc_item;
proto_tree *amr_tree, *toc_tree;
/* Make entries in Protocol column and Info column on summary display */
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "AMR");
if (tree) {
ti = proto_tree_add_item(tree, proto_amr, tvb, 0, -1, FALSE);
amr_tree = proto_item_add_subtree(ti, ett_amr);
/* add an item to the subtree, see section 1.6 for more information */
proto_tree_add_item(amr_tree, hf_amr_cmr, tvb, offset, 1, FALSE);
if ( !octet_aligned )
return; /* only handle octet aligned for now */
proto_tree_add_item(amr_tree, hf_amr_reserved, tvb, offset, 1, FALSE);
offset++;
toc_offset = offset;
/* If interleaced ILL and ILP follows here */
/* Payload Table of Contents
* A ToC entry takes the following format in octet-aligned mode:
*
* 0 1 2 3 4 5 6 7
* +-+-+-+-+-+-+-+-+
* |F| FT |Q|P|P|
* +-+-+-+-+-+-+-+-+
*/
octet = tvb_get_guint8(tvb,offset);
toc_item = proto_tree_add_text(amr_tree, tvb, offset, -1, "Payload Table of Contents");
toc_tree = proto_item_add_subtree(toc_item, ett_amr_toc);
while ( ( octet& 0x80 ) == 0x80 ){
octet = tvb_get_guint8(tvb,offset);
proto_tree_add_item(amr_tree, hf_amr_toc_f, tvb, offset, 1, FALSE);
proto_tree_add_item(amr_tree, hf_amr_toc_ft, tvb, offset, 1, FALSE);
proto_tree_add_item(amr_tree, hf_amr_toc_q, tvb, offset, 1, FALSE);
offset++;
}
/* Continue adding tree items to process the packet here */
}/* if tree */
/* If this protocol has a sub-dissector call it here, see section 1.8 */
}
/* Register the protocol with Ethereal */
/* 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_amr(void)
{
dissector_handle_t amr_handle;
static int amr_prefs_initialized = FALSE;
amr_handle = create_dissector_handle(dissect_amr, proto_amr);
if (!amr_prefs_initialized) {
amr_prefs_initialized = TRUE;
}
else {
if ( dynamic_payload_type > 95 )
dissector_delete("rtp.pt", dynamic_payload_type, amr_handle);
}
dynamic_payload_type = temp_dynamic_payload_type;
if ( dynamic_payload_type > 95 ){
dissector_add("rtp.pt", dynamic_payload_type, amr_handle);
}
}
/* this format is require because a script is used to build the C function
that calls all the protocol registration.
*/
void
proto_register_amr(void)
{
module_t *amr_module;
/* Setup list of header fields See Section 1.6.1 for details*/
static hf_register_info hf[] = {
{ &hf_amr_cmr,
{ "CMR", "amr.cmr",
FT_UINT8, BASE_DEC, VALS(amr_codec_mode_request_vals), 0xf0,
"codec mode request", HFILL }
},
{ &hf_amr_reserved,
{ "Reserved", "amr.reserved",
FT_UINT8, BASE_DEC, NULL, 0x0f,
"Reserved bits", HFILL }
},
{ &hf_amr_toc_f,
{ "F bit", "amr.toc.f",
FT_BOOLEAN, 8, TFS(&toc_f_bit_vals), 0x80,
"F bit", HFILL }
},
{ &hf_amr_toc_ft,
{ "FT bits", "amr.toc.ft",
FT_UINT8, BASE_DEC, VALS(amr_codec_mode_request_vals), 0x78,
"FT bits", HFILL }
},
{ &hf_amr_toc_q,
{ "Q bit", "amr.toc.q",
FT_BOOLEAN, 8, TFS(&toc_q_bit_vals), 0x04,
"Frame quality indicator bit", HFILL }
},
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_amr,
&ett_amr_toc,
};
/* Register the protocol name and description */
proto_amr = proto_register_protocol("Adaptive Multi-Rate","AMR", "amr");
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_amr, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* Register a configuration option for port */
amr_module = prefs_register_protocol(proto_amr, proto_reg_handoff_amr);
prefs_register_uint_preference(amr_module, "dynamic.payload.type",
"AMR dynamic payload type",
"The dynamic payload type which will be interpretyed as AMR",
10,
&temp_dynamic_payload_type);
}
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