/* packet-llt.c
 * Routines for Veritas Low Latency Transport (LLT) dissection
 * Copyright 2006, Stephen Fisher <stephentfisher@yahoo.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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <glib.h>

#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/etypes.h>

static const value_string message_type_vs[] = {
  { 0x0a, "heartbeat" },
  { 0, NULL}
};

/* Forward declaration we need below */
void proto_reg_handoff_llt(void);

/* Variables for our preferences */
static guint preference_alternate_ethertype = 0x0;

/* Behind the scenes variable to keep track of the last preference setting */
static guint preference_alternate_ethertype_last;

/* Initialize the protocol and registered fields */
static int proto_llt = -1;

static int hf_llt_cluster_num = -1;
static int hf_llt_node_id = -1;
static int hf_llt_message_type = -1;
static int hf_llt_sequence_num = -1;
static int hf_llt_message_time = -1;

/* Initialize the subtree pointers */
static gint ett_llt = -1;

static dissector_handle_t llt_handle; /* Declaring this here allows us to use it for re-registration throughout the handoff function */

/* Code to actually dissect the packets */
static void
dissect_llt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
	/* Set up structures needed to add the protocol subtree and manage it */
	proto_item *ti=NULL;
	proto_tree *llt_tree=NULL;
	guint8 message_type;

	/* 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, "LLT");

	message_type = tvb_get_guint8(tvb, 3);

	if(check_col(pinfo->cinfo, COL_INFO)) {
		col_clear(pinfo->cinfo, COL_INFO);
		col_add_fstr(pinfo->cinfo, COL_INFO, "Message type: %s", val_to_str(message_type, message_type_vs, "Unknown (0x%02x)"));
	}

	if (tree) {
		ti = proto_tree_add_item(tree, proto_llt, tvb, 0, -1, FALSE);
		llt_tree = proto_item_add_subtree(ti, ett_llt);
	}

	proto_tree_add_item(llt_tree, hf_llt_cluster_num, tvb, 2, 1, FALSE);
	proto_tree_add_item(llt_tree, hf_llt_message_type, tvb, 3, 1, FALSE);
	proto_tree_add_item(llt_tree, hf_llt_node_id, tvb, 7, 1, FALSE);
	proto_tree_add_item(llt_tree, hf_llt_sequence_num, tvb, 24, 4, FALSE);
	proto_tree_add_item(llt_tree, hf_llt_message_time, tvb, 40, 4, FALSE);

}

/* Register the protocol with Wireshark */
void
proto_register_llt(void)
{
	module_t *llt_module;

	static hf_register_info hf[] = {

		{ &hf_llt_cluster_num,  { "Cluster number", "llt.cluster_num",
					  FT_UINT8, BASE_DEC, NULL, 0,
					  "Cluster number that this node belongs to", HFILL } },

		{ &hf_llt_message_type, { "Message type", "llt.message_type",
					  FT_UINT8, BASE_HEX, VALS(message_type_vs), 0,
					  "Type of LLT message contained in this frame", HFILL } },

		{ &hf_llt_node_id,      { "Node ID", "llt.node_id",
					  FT_UINT8, BASE_DEC, NULL, 0,
					  "Number identifying this node within the cluster", HFILL } },

		{ &hf_llt_sequence_num, { "Sequence number", "llt.sequence_num",
					  FT_UINT32, BASE_DEC, NULL, 0,
					  "Sequence number of this frame", HFILL } },

		{ &hf_llt_message_time, { "Message time", "llt.message_time",
					  FT_UINT32, BASE_DEC, NULL, 0,
					  "Number of ticks since this node was last rebooted", HFILL } }
	};

	/* Setup protocol subtree array */
	static gint *ett[] = {
		&ett_llt,
	};

	/* Register the protocol name and description */
	proto_llt = proto_register_protocol("Veritas Low Latency Transport (LLT)", "LLT", "llt");

	/* Required function calls to register the header fields and subtrees used */
	proto_register_field_array(proto_llt, hf, array_length(hf));
	proto_register_subtree_array(ett, array_length(ett));

	/* Register preferences module */
	llt_module = prefs_register_protocol(proto_llt, proto_reg_handoff_llt);

	/* Register our preferences */
	prefs_register_uint_preference(llt_module, "alternate_ethertype", "Alternate ethertype value",
				       "Dissect this ethertype as LLT traffic in addition to the default, 0xCAFE.",
				       16, &preference_alternate_ethertype); /* A base-16 (hexadecimal) value */

}


void
proto_reg_handoff_llt(void)
{
	llt_handle = create_dissector_handle(dissect_llt, proto_llt);
	dissector_add("ethertype", ETHERTYPE_LLT, llt_handle);

	if((preference_alternate_ethertype != ETHERTYPE_LLT)
	&& (preference_alternate_ethertype != 0x0)){
		dissector_delete("ethertype", preference_alternate_ethertype_last, llt_handle);
		preference_alternate_ethertype_last = preference_alternate_ethertype; /* Save the setting to see if it has changed later */
		dissector_add("ethertype", preference_alternate_ethertype, llt_handle); /* Register the new ethertype setting */
	}
}