From Haakon Nessjoen: New dissector for Digiums TDMoE protocol

From me: A few minor changes:
- col-clear() not req'd;
- Use 'gint32 length' rather than 'guint8 length';
- Use ENC_NA instead of FALSE/TRUE in two cases;
- Move global tdmoe_handle to be local to proto_reg_handoff...

svn path=/trunk/; revision=33307

1 files changed, 172 insertions, 0 deletions

diff --git a/epan/dissectors/packet-tdmoe.c b/epan/dissectors/packet-tdmoe.c
new file mode 100644
index 0000000000..f9403331fe
--- /dev/null
+++ b/epan/dissectors/packet-tdmoe.c
@@ -0,0 +1,172 @@
+/* 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_NA/*??*/);
+		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(tvb, offset, -1, -1);
+		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", 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("ethertype", ETHERTYPE_TDMOE, tdmoe_handle);
+
+	data_handle = find_dissector("data");
+}