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/* packet-tdmoe.c
* Routines for TDM over Ethernet packet disassembly
* Copyright 2010, Haakon Nessjoen <haakon.nessjoen@gmail.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.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <glib.h>
#include <epan/packet.h>
#include <epan/etypes.h>
/* Bitmasks for the flags in the fourth byte of the packet */
#define TDMOE_YELLOW_ALARM_BITMASK 0x01
#define TDMOE_SIGBITS_BITMASK 0x02
/* protocols and header fields */
static int proto_tdmoe = -1;
static int hf_tdmoe_subaddress = -1;
static int hf_tdmoe_samples = -1;
static int hf_tdmoe_flags = -1;
static int hf_tdmoe_yellow_alarm = -1;
static int hf_tdmoe_sig_bits_present = -1;
static int hf_tdmoe_packet_counter = -1;
static int hf_tdmoe_channels = -1;
static int hf_tdmoe_sig_bits = -1;
static gint ett_tdmoe = -1;
static gint ett_tdmoe_flags = -1;
static dissector_handle_t data_handle;
static int
dissect_tdmoe(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *ti;
proto_tree *tdmoe_tree;
tvbuff_t *next_client;
guint16 channels;
guint16 subaddress;
/* Check that there's enough data */
if (tvb_length(tvb) < 8)
return 0;
subaddress = tvb_get_ntohs(tvb, 0);
channels = tvb_get_ntohs(tvb, 6);
col_set_str(pinfo->cinfo, COL_PROTOCOL, "TDMoE");
col_add_fstr(pinfo->cinfo, COL_INFO, "Subaddress: %d Channels: %d %s",
subaddress,
channels,
(tvb_get_guint8(tvb, 3) & TDMOE_YELLOW_ALARM_BITMASK ? "[YELLOW ALARM]" : "")
);
if (tree) {
gint32 offset = 0;
static const gint *flags[] = { &hf_tdmoe_yellow_alarm, &hf_tdmoe_sig_bits_present, NULL };
/* create display subtree for the protocol */
ti = proto_tree_add_item(tree, proto_tdmoe, tvb, 0, -1, ENC_NA);
tdmoe_tree = proto_item_add_subtree(ti, ett_tdmoe);
/* Subaddress */
proto_tree_add_item(tdmoe_tree, hf_tdmoe_subaddress, tvb, offset, 2, ENC_BIG_ENDIAN);
offset+=2;
/* Samples (1 byte) */
proto_tree_add_item(tdmoe_tree, hf_tdmoe_samples, tvb, offset, 1, ENC_NA);
offset++;
/* Yellow alarm & "Sig bits present" bits (1 byte) */
proto_tree_add_bitmask(tdmoe_tree, tvb, offset, hf_tdmoe_flags, ett_tdmoe_flags, flags, ENC_BIG_ENDIAN);
offset++;
/* Packet counter (2 bytes) */
proto_tree_add_item(tdmoe_tree, hf_tdmoe_packet_counter, tvb, offset, 2, ENC_BIG_ENDIAN);
offset+=2;
/* Number of channels in packet (2 bytes) */
proto_tree_add_item(tdmoe_tree, hf_tdmoe_channels, tvb, offset, 2, ENC_BIG_ENDIAN);
offset+=2;
if (tvb_get_guint8(tvb, 3) & TDMOE_SIGBITS_BITMASK) {
/* 4 sigbits per channel. Might be different on other sub-protocols? */
guint16 length = (channels >> 1) + ((channels & 0x01) ? 1 : 0);
proto_tree_add_item(tdmoe_tree, hf_tdmoe_sig_bits, tvb, offset, length, ENC_NA);
offset += length;
}
/* The rest is SAMPLES * CHANNELS bytes of channel data */
next_client = tvb_new_subset_remaining(tvb, offset);
return call_dissector(data_handle, next_client, pinfo, tdmoe_tree);
}
return tvb_reported_length(tvb);
}
void
proto_register_tdmoe(void)
{
static hf_register_info hf[] = {
{ &hf_tdmoe_subaddress,
{ "Subaddress", "tdmoe.subaddress", FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_tdmoe_samples,
{ "Samples", "tdmoe.samples", FT_UINT8, BASE_DEC, NULL, 0x0,
"Samples per channel", HFILL }},
{ &hf_tdmoe_flags,
{ "Flags", "tdmoe.flags", FT_UINT8, BASE_HEX, NULL, 0x0,
NULL, HFILL }},
{ &hf_tdmoe_yellow_alarm,
{ "Yellow Alarm", "tdmoe.yellowalarm", FT_BOOLEAN, 8, NULL, TDMOE_YELLOW_ALARM_BITMASK,
NULL, HFILL }},
{ &hf_tdmoe_sig_bits_present,
{ "Sig bits present", "tdmoe.sig_bits_present", FT_BOOLEAN, 8, NULL, TDMOE_SIGBITS_BITMASK,
NULL, HFILL }},
{ &hf_tdmoe_packet_counter,
{ "Counter", "tdmoe.counter", FT_UINT16, BASE_DEC, NULL, 0x0,
"Packet number", HFILL }},
{ &hf_tdmoe_channels,
{ "Channels", "tdmoe.channels", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL }},
{ &hf_tdmoe_sig_bits,
{ "Sig bits", "tdmoe.sig_bits", FT_BYTES, BASE_NONE, NULL, 0x0,
NULL, HFILL }},
};
static gint *ett[] = {
&ett_tdmoe,
&ett_tdmoe_flags
};
proto_tdmoe = proto_register_protocol("Digium TDMoE Protocol", "TDMoE", "tdmoe");
proto_register_field_array(proto_tdmoe, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_tdmoe(void)
{
dissector_handle_t tdmoe_handle;
tdmoe_handle = new_create_dissector_handle(dissect_tdmoe, proto_tdmoe);
dissector_add_uint("ethertype", ETHERTYPE_TDMOE, tdmoe_handle);
data_handle = find_dissector("data");
}
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