/* packet-lmi.c
 * Routines for Frame Relay Local Management Interface (LMI) disassembly
 * Copyright 2001, Jeffrey C. Foster <jfoste@woodward.com>
 *
 * $Id$
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998
 *
 * 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.
 *
 * ToDo:
 *
 * References:
 *
 * http://www.techfest.com/networking/wan/frrel.htm
 * http://www.frforum.com/5000/Approved/FRF.1.2/frf1_2.pdf
 * http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/frame.htm#xtocid18
 * http://www.net.aapt.com.au/techref/lmimess.htm
 * http://www.raleigh.ibm.com:80/cgi-bin/bookmgr/BOOKS/EZ305800/1.2.4.4
 */


#include "config.h"

#include <glib.h>
#include <epan/packet.h>
#include <epan/nlpid.h>

static int proto_lmi = -1;
static int hf_lmi_call_ref = -1;
static int hf_lmi_msg_type = -1;
static int hf_lmi_inf_ele = -1;
static int hf_lmi_inf_len = -1;

static int hf_lmi_rcd_type = -1;
static int hf_lmi_send_seq = -1;
static int hf_lmi_recv_seq = -1;
static int hf_lmi_dlci_high = -1;
static int hf_lmi_dlci_low = -1;
static int hf_lmi_new = -1;
static int hf_lmi_act = -1;

static gint ett_lmi = -1;
static gint ett_lmi_ele = -1;

#ifdef _OLD_
/*
 * Bits in the address field.
 */
#define	LMI_CMD		0xf000	/* LMI Command */
#define	LMI_SEQ		0x0fff	/* LMI Sequence number */

#endif

static const value_string msg_type_str[] = {
	{0x75, "Status Enquiry"},
        {0x7D, "Status"},
	{ 0,       NULL }
        };

static const value_string element_type_str[] = {

/*** These are the ANSI values ***/
	{0x01, "Report"},
        {0x03, "Keep Alive"},
        {0x07, "PVC Status"},

/*** These are the ITU values ***/
        {0x51, "Report"},
        {0x53, "Keep Alive"},
        {0x07, "PVC Status"},

	{ 0,       NULL }
        };

static const value_string record_type_str[] = {
        {0x00, "Full Status"},
        {0x01, "Link Integrity Verification Only"},
        {0x02, "Single PVC"},
	{ 0,       NULL }
        };

static const value_string pvc_status_new_str[] = {
        {0x00, "PVC already present"},
        {0x01, "PVC is new"},
	{ 0,       NULL }
        };

static const value_string pvc_status_act_str[] = {
        {0x00, "PVC is Inactive"},
        {0x01, "PVC is Active"},
	{ 0,       NULL }
        };

static void
dissect_lmi_report_type(tvbuff_t *tvb, int offset, proto_tree *tree)
{
	proto_tree_add_uint(tree, hf_lmi_rcd_type, tvb, offset, 1, tvb_get_guint8( tvb, offset));
}

static void
dissect_lmi_link_int(tvbuff_t *tvb, int offset, proto_tree *tree)
{
	proto_tree_add_uint(tree, hf_lmi_send_seq, tvb, offset, 1, tvb_get_guint8( tvb, offset));
	++offset;
	proto_tree_add_uint(tree, hf_lmi_recv_seq, tvb, offset, 1, tvb_get_guint8( tvb, offset));

}

static void
dissect_lmi_pvc_status(tvbuff_t *tvb, int offset, proto_tree *tree)
{
        proto_tree_add_uint(tree, hf_lmi_dlci_high, tvb, offset, 1, tvb_get_guint8( tvb, offset));
	++offset;
        proto_tree_add_uint(tree, hf_lmi_dlci_low, tvb, offset, 1, tvb_get_guint8( tvb, offset));
	++offset;
        proto_tree_add_uint(tree, hf_lmi_new, tvb, offset, 1, tvb_get_guint8( tvb, offset));
        proto_tree_add_uint(tree, hf_lmi_act, tvb, offset, 1, tvb_get_guint8( tvb, offset));
}

static void
dissect_lmi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
	proto_tree	*lmi_tree = NULL, *lmi_subtree;
	proto_item	*ti;
	int		offset = 2, len;
	guint8		msg_type;
	guint8		ele_id;

	col_set_str(pinfo->cinfo, COL_PROTOCOL, "LMI");
	col_clear(pinfo->cinfo, COL_INFO);

	if (tree) {
		ti = proto_tree_add_item(tree, proto_lmi, tvb, 0, 3, ENC_NA);
		lmi_tree = proto_item_add_subtree(ti, ett_lmi_ele);

		proto_tree_add_item(lmi_tree, hf_lmi_call_ref, tvb, 0, 1, ENC_BIG_ENDIAN);
	}
	msg_type = tvb_get_guint8( tvb, 1);
	col_add_str(pinfo->cinfo, COL_INFO,
		    val_to_str(msg_type, msg_type_str, "Unknown message type (0x%02x)"));

	if (tree) {
		proto_tree_add_uint(lmi_tree, hf_lmi_msg_type, tvb, 1, 1, msg_type);

	/* Display the LMI elements */
		while (tvb_reported_length_remaining(tvb, offset) > 0) {
			ele_id = tvb_get_guint8( tvb, offset);
			len =  tvb_get_guint8( tvb, offset + 1);

			ti = proto_tree_add_text(lmi_tree, tvb, offset, len + 2,
				"Information Element: %s",
				val_to_str(ele_id, element_type_str, "Unknown (%u)"));

			lmi_subtree = proto_item_add_subtree(ti, ett_lmi_ele);

	                proto_tree_add_uint(lmi_subtree, hf_lmi_inf_ele, tvb, offset, 1,
				ele_id);
			++offset;
	                proto_tree_add_uint(lmi_subtree, hf_lmi_inf_len, tvb, offset, 1, len);
			++offset;
			if (( ele_id == 1) || (ele_id == 51))
				dissect_lmi_report_type( tvb, offset, lmi_subtree);
			else if (( ele_id == 3) || (ele_id == 53))
				dissect_lmi_link_int( tvb, offset, lmi_subtree);
			else if (( ele_id == 7) || (ele_id == 57))
				dissect_lmi_pvc_status( tvb, offset, lmi_subtree);
			offset += len;
		}
	}
	else {
		lmi_tree = NULL;
	}
}


void
proto_register_lmi(void)
{
    static hf_register_info hf[] = {
	{ &hf_lmi_call_ref,
	  { "Call reference", "lmi.cmd", FT_UINT8, BASE_HEX, NULL, 0,
	  	NULL, HFILL }},

	{ &hf_lmi_msg_type,
	  { "Message Type", "lmi.msg_type", FT_UINT8, BASE_HEX, VALS(msg_type_str), 0,
	  	NULL, HFILL }},

	{ &hf_lmi_inf_ele,
	  { "Type", "lmi.inf_ele_type", FT_UINT8, BASE_DEC, VALS(element_type_str), 0,
	  	"Information Element Type", HFILL }},
	{ &hf_lmi_inf_len,
	  { "Length", "lmi.inf_ele_len", FT_UINT8, BASE_DEC, NULL, 0,
	  	"Information Element Length", HFILL }},

	{ &hf_lmi_rcd_type,
	  { "Record Type", "lmi.ele_rcd_type", FT_UINT8, BASE_DEC, VALS(record_type_str), 0,
	  	NULL, HFILL }},
	{ &hf_lmi_send_seq,
	  { "Send Seq", "lmi.send_seq", FT_UINT8, BASE_DEC, NULL, 0,
	  	"Send Sequence", HFILL }},
	{ &hf_lmi_recv_seq,
	  { "Recv Seq", "lmi.recv_seq", FT_UINT8, BASE_DEC, NULL, 0,
	  	"Receive Sequence", HFILL }},
	{ &hf_lmi_dlci_high,
	  { "DLCI High", "lmi.dlci_hi", FT_UINT8, BASE_DEC, NULL, 0x3f,
	  	"DLCI High bits", HFILL }},
	{ &hf_lmi_dlci_low,
	  { "DLCI Low", "lmi.dlci_low", FT_UINT8, BASE_DEC, NULL, 0x78,
	  	"DLCI Low bits", HFILL }},
	{ &hf_lmi_new,
	  { "DLCI New", "lmi.dlci_new", FT_UINT8, BASE_DEC, VALS(pvc_status_new_str), 0x08,
	  	"DLCI New Flag", HFILL }},
	{ &hf_lmi_act,
	  { "DLCI Active","lmi.dlci_act", FT_UINT8, BASE_DEC, VALS(pvc_status_act_str), 0x02,
	  	"DLCI Active Flag", HFILL }},
    };
    static gint *ett[] = {
        &ett_lmi,
        &ett_lmi_ele,
    };
    proto_lmi = proto_register_protocol ("Local Management Interface", "LMI", "lmi");
    proto_register_field_array (proto_lmi, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));

}

void
proto_reg_handoff_lmi(void)
{
	dissector_handle_t lmi_handle;

	lmi_handle = create_dissector_handle(dissect_lmi, proto_lmi);
	dissector_add_uint("fr.nlpid", NLPID_LMI, lmi_handle);
}
