/* packet-fefd.c
 * Routines for the disassembly of the "Far End Failure Detection"
 *
 * $Id$
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.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, ENC_NA);
        fefd_tree = proto_item_add_subtree(ti, ett_fefd);

        /* FEFD header */
        proto_tree_add_item(fefd_tree, hf_fefd_version, tvb, offset, 1, ENC_BIG_ENDIAN);
        proto_tree_add_item(fefd_tree, hf_fefd_opcode, tvb, offset, 1, ENC_BIG_ENDIAN);
        offset += 1;
        flags_ti = proto_tree_add_item(fefd_tree, hf_fefd_flags, tvb, offset, 1, ENC_BIG_ENDIAN);
        flags_tree = proto_item_add_subtree(flags_ti, ett_fefd_flags);
        proto_tree_add_item(flags_tree, hf_fefd_flags_rt, tvb, offset, 1, ENC_BIG_ENDIAN);
        proto_tree_add_item(flags_tree, hf_fefd_flags_rsy, tvb, offset, 1, ENC_BIG_ENDIAN);
        offset += 1;
        proto_tree_add_item(fefd_tree, hf_fefd_checksum, tvb, offset, 2, ENC_BIG_ENDIAN);
        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 */

            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;
            }

            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_uint("llc.force10_pid", 0x0111, fefd_handle);
}
