/* packet-fefd.c
 * Routines for the disassembly of the "Far End Failure Detection"
 *
 * $Id: packet-fefd.c 32410 2010-04-06 21:14:01Z wmeier $
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * Copied from packet-udld.c
 *
 * 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 <stdlib.h>

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

#include <epan/oui.h>
#include <epan/nlpid.h>



/* Offsets in TLV structure. */
#define	TLV_TYPE	0
#define	TLV_LENGTH	2

static int proto_fefd = -1;
static int hf_fefd_version = -1;
static int hf_fefd_opcode = -1;
static int hf_fefd_flags = -1;
static int hf_fefd_flags_rt = -1;
static int hf_fefd_flags_rsy = -1;
static int hf_fefd_checksum = -1;
static int hf_fefd_tlvtype = -1;
static int hf_fefd_tlvlength = -1;

static gint ett_fefd = -1;
static gint ett_fefd_flags = -1;
static gint ett_fefd_tlv = -1;

static dissector_handle_t data_handle;

#define TYPE_DEVICE_ID        0x0001
#define TYPE_PORT_ID          0x0002
#define TYPE_ECHO             0x0003
#define TYPE_MESSAGE_INTERVAL 0x0004
#define TYPE_TIMEOUT_INTERVAL 0x0005
#define TYPE_DEVICE_NAME      0x0006
#define TYPE_SEQUENCE_NUMBER  0x0007


static const value_string type_vals[] = {
	{ TYPE_DEVICE_ID,          "Device ID" },
	{ TYPE_PORT_ID,            "Port ID" },
	{ TYPE_ECHO,               "Echo" },
	{ TYPE_MESSAGE_INTERVAL,   "Message interval" },
	{ TYPE_TIMEOUT_INTERVAL,   "Timeout interval" },
	{ TYPE_DEVICE_NAME,        "Device name" },
	{ TYPE_SEQUENCE_NUMBER,    "Sequence number" },
	{ 0,                       NULL }
};

#define OPCODE_RESERVED       0x00
#define OPCODE_PROBE          0x01
#define OPCODE_ECHO           0x02
#define OPCODE_FLUSH          0x03

static const value_string opcode_vals[] = {
	{ OPCODE_RESERVED, "Reserved" },
	{ OPCODE_PROBE,    "Probe" },
	{ OPCODE_ECHO,     "Echo" },
	{ OPCODE_FLUSH,    "Flush" },
	{ 0,               NULL }
};

static void
dissect_fefd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    proto_item *ti;
    proto_tree *fefd_tree = NULL;
    int offset = 0;
    guint16 type;
    guint16 length;
    proto_item *tlvi;
    proto_tree *tlv_tree;
    int real_length;

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

    if (tree) {
	proto_item *flags_ti;
	proto_tree *flags_tree;

	ti = proto_tree_add_item(tree, proto_fefd, tvb, offset, -1, FALSE);
	fefd_tree = proto_item_add_subtree(ti, ett_fefd);

	/* FEFD header */
	proto_tree_add_item(fefd_tree, hf_fefd_version, tvb, offset, 1, FALSE);
	proto_tree_add_item(fefd_tree, hf_fefd_opcode, tvb, offset, 1, FALSE);
	offset += 1;
	flags_ti = proto_tree_add_item(fefd_tree, hf_fefd_flags, tvb, offset, 1, FALSE);
	flags_tree = proto_item_add_subtree(ti, ett_fefd_flags);
	proto_tree_add_item(flags_tree, hf_fefd_flags_rt, tvb, offset, 1, FALSE);
	proto_tree_add_item(flags_tree, hf_fefd_flags_rsy, tvb, offset, 1, FALSE);
	offset += 1;
	proto_tree_add_item(fefd_tree, hf_fefd_checksum, tvb, offset, 2, FALSE);
	offset += 2;
    } else {
	offset += 4; /* The version/opcode/flags/checksum fields from above */
    }

	while (tvb_reported_length_remaining(tvb, offset) != 0) {
	    type = tvb_get_ntohs(tvb, offset + TLV_TYPE);
	    length = tvb_get_ntohs(tvb, offset + TLV_LENGTH);
	    if (length < 4) {
		if (tree) {
		    tlvi = proto_tree_add_text(fefd_tree, tvb, offset, 4,
			"TLV with invalid length %u (< 4)",
			length);
		    tlv_tree = proto_item_add_subtree(tlvi, ett_fefd_tlv);
		    proto_tree_add_uint(tlv_tree, hf_fefd_tlvtype, tvb,
				offset + TLV_TYPE, 2, type);
		    proto_tree_add_uint(tlv_tree, hf_fefd_tlvlength, tvb,
				offset + TLV_LENGTH, 2, length);
		}
		offset += 4;
		break;
	    }

	    switch (type) {

	    case TYPE_DEVICE_ID:
		/* Device ID */

		if (check_col(pinfo->cinfo, COL_INFO))
		    col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL,
				    "Device ID: %s",
				    tvb_format_stringzpad(tvb, offset + 4,
							  length - 4));

		if (tree) {
		    tlvi = proto_tree_add_text(fefd_tree, tvb, offset,
				length, "Device ID: %s",
				tvb_format_stringzpad(tvb, offset + 4, length - 4));
		    tlv_tree = proto_item_add_subtree(tlvi, ett_fefd_tlv);
		    proto_tree_add_uint(tlv_tree, hf_fefd_tlvtype, tvb,
				offset + TLV_TYPE, 2, type);
		    proto_tree_add_uint(tlv_tree, hf_fefd_tlvlength, tvb,
				offset + TLV_LENGTH, 2, length);
		    proto_tree_add_text(tlv_tree, tvb, offset + 4,
				length - 4, "Device ID: %s",
				tvb_format_stringzpad(tvb, offset + 4, length - 4));
		}
		offset += length;
		break;

	    case TYPE_PORT_ID:
		real_length = length;
		if (tvb_get_guint8(tvb, offset + real_length) != 0x00) {
		    /* The length in the TLV doesn't appear to be the
		       length of the TLV, as the byte just past it
		       isn't the first byte of a 2-byte big-endian
		       small integer; make the length of the TLV the length
		       in the TLV, plus 4 bytes for the TLV type and length,
		       minus 1 because that's what makes one capture work. */
		    real_length = length + 3;
		}

		if (check_col(pinfo->cinfo, COL_INFO))
		    col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL,
				    "Port ID: %s",
				    tvb_format_stringzpad(tvb, offset + 4, real_length - 4));

		if (tree) {
		    tlvi = proto_tree_add_text(fefd_tree, tvb, offset,
			    real_length, "Port ID: %s",
			    tvb_format_text(tvb, offset + 4, real_length - 4));
		    tlv_tree = proto_item_add_subtree(tlvi, ett_fefd_tlv);
		    proto_tree_add_uint(tlv_tree, hf_fefd_tlvtype, tvb,
			    offset + TLV_TYPE, 2, type);
		    proto_tree_add_uint(tlv_tree, hf_fefd_tlvlength, tvb,
			    offset + TLV_LENGTH, 2, length);
		    proto_tree_add_text(tlv_tree, tvb, offset + 4,
			    real_length - 4,
			    "Sent through Interface: %s",
			    tvb_format_text(tvb, offset + 4, real_length - 4));
		}
		offset += real_length;
		break;

	    case TYPE_ECHO:
	    case TYPE_MESSAGE_INTERVAL:
	    case TYPE_TIMEOUT_INTERVAL:
	    case TYPE_DEVICE_NAME:
	    case TYPE_SEQUENCE_NUMBER:
	    default:
		tlvi = proto_tree_add_text(fefd_tree, tvb, offset,
			length, "Type: %s, length: %u",
			val_to_str(type, type_vals, "Unknown (0x%04x)"),
			length);
		tlv_tree = proto_item_add_subtree(tlvi, ett_fefd_tlv);
		proto_tree_add_uint(tlv_tree, hf_fefd_tlvtype, tvb,
			offset + TLV_TYPE, 2, type);
		proto_tree_add_uint(tlv_tree, hf_fefd_tlvlength, tvb,
			offset + TLV_LENGTH, 2, length);
		if (length > 4) {
			proto_tree_add_text(tlv_tree, tvb, offset + 4,
				length - 4, "Data");
		} else {
			return;
		}
		offset += length;
	    }
	}

    call_dissector(data_handle, tvb_new_subset_remaining(tvb, offset), pinfo, fefd_tree);
}

void
proto_register_fefd(void)
{
    static hf_register_info hf[] = {
	{ &hf_fefd_version,
	{ "Version",		"fefd.version",  FT_UINT8, BASE_DEC, NULL, 0xE0,
	  NULL, HFILL }},

	{ &hf_fefd_opcode,
	{ "Opcode",		"fefd.opcode", FT_UINT8, BASE_DEC, VALS(opcode_vals), 0x1F,
	  NULL, HFILL }},

	{ &hf_fefd_flags,
	{ "Flags",		"fefd.flags", FT_UINT8, BASE_HEX, NULL, 0x0,
	  NULL, HFILL }},

	{ &hf_fefd_flags_rt,
	{ "Recommended timeout",		"fefd.flags.rt", FT_BOOLEAN, 8, NULL, 0x80,
	  NULL, HFILL }},

	{ &hf_fefd_flags_rsy,
	{ "ReSynch",		"fefd.flags.rsy", FT_BOOLEAN, 8, NULL, 0x40,
	  NULL, HFILL }},

	{ &hf_fefd_checksum,
	{ "Checksum",		"fefd.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
	  NULL, HFILL }},

	{ &hf_fefd_tlvtype,
	{ "Type",		"fefd.tlv.type", FT_UINT16, BASE_HEX, VALS(type_vals), 0x0,
	  NULL, HFILL }},

	{ &hf_fefd_tlvlength,
	{ "Length",		"fefd.tlv.len", FT_UINT16, BASE_DEC, NULL, 0x0,
	  NULL, HFILL }}
    };
    static gint *ett[] = {
	&ett_fefd,
	&ett_fefd_flags,
	&ett_fefd_tlv
    };

    proto_fefd = proto_register_protocol("Far End Failure Detection", "FEFD", "fefd");
    proto_register_field_array(proto_fefd, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
}

void
proto_reg_handoff_fefd(void)
{
    dissector_handle_t fefd_handle;

    data_handle = find_dissector("data");
    fefd_handle = create_dissector_handle(dissect_fefd, proto_fefd);
    dissector_add("llc.force10_pid", 0x0111, fefd_handle);
}
