/* packet-fefd.c
 * Routines for the disassembly of the "Far End Failure Detection"
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * Copied from packet-udld.c
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"

#include <epan/packet.h>


void proto_register_fefd(void);
void proto_reg_handoff_fefd(void);

/* 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 int hf_fefd_device_id = -1;
static int hf_fefd_sent_through_interface = -1;
static int hf_fefd_data = -1;

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

#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 int
dissect_fefd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
    proto_item *ti;
    proto_tree *fefd_tree = NULL;
    int         offset    = 0;
    guint16     type;
    guint16     length;
    proto_tree *tlv_tree;
    int         real_length;
    static int * const flags[] = {
        &hf_fefd_flags_rt,
        &hf_fefd_flags_rsy,
        NULL
    };
    static int * const headers[] = {
        &hf_fefd_version,
        &hf_fefd_opcode,
        NULL
    };

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

    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_bitmask_list(fefd_tree, tvb, offset, 1, headers, ENC_BIG_ENDIAN);
    offset += 1;
    proto_tree_add_bitmask(fefd_tree, tvb, offset, hf_fefd_flags, ett_fefd_flags, flags, ENC_BIG_ENDIAN);
    offset += 1;
    proto_tree_add_checksum(fefd_tree, tvb, offset, hf_fefd_checksum, -1, NULL, pinfo, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
    offset += 2;

    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) {
                tlv_tree = proto_tree_add_subtree_format(fefd_tree, tvb, offset, 4,  /* XXX - expert info? */
                                           ett_fefd_tlv, NULL, "TLV with invalid length %u (< 4)",
                                           length);
                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) {
                tlv_tree = proto_tree_add_subtree_format(fefd_tree, tvb, offset,
                                           length, ett_fefd_tlv, NULL, "Device ID: %s",
                                           tvb_format_stringzpad(tvb, offset + 4, length - 4));
                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_item(tlv_tree, hf_fefd_device_id, tvb, offset + 4,
                                    length - 4, ENC_NA|ENC_ASCII);
            }
            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) {
                tlv_tree = proto_tree_add_subtree_format(fefd_tree, tvb, offset,
                                           real_length, ett_fefd_tlv, NULL, "Port ID: %s",
                                           tvb_format_text(tvb, offset + 4, real_length - 4));
                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_item(tlv_tree, hf_fefd_sent_through_interface, tvb, offset + 4,
                                    real_length - 4, ENC_NA|ENC_ASCII);
            }
            offset += real_length;
            break;

        case TYPE_ECHO:
        case TYPE_MESSAGE_INTERVAL:
        case TYPE_TIMEOUT_INTERVAL:
        case TYPE_DEVICE_NAME:
        case TYPE_SEQUENCE_NUMBER:
        default:
            tlv_tree = proto_tree_add_subtree_format(fefd_tree, tvb, offset,
                                       length, ett_fefd_tlv, NULL, "Type: %s, length: %u",
                                       val_to_str(type, type_vals, "Unknown (0x%04x)"),
                                       length);
            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_item(tlv_tree, hf_fefd_data, tvb, offset + 4,
                                    length - 4, ENC_NA);
            } else {
                return tvb_captured_length(tvb);
            }
            offset += length;
        }
    }

    call_data_dissector(tvb_new_subset_remaining(tvb, offset), pinfo, fefd_tree);
    return tvb_captured_length(tvb);
}

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 }},

        { &hf_fefd_device_id,
          { "Device ID",           "fefd.device_id", FT_STRINGZ, BASE_NONE, NULL, 0x0,
            NULL, HFILL }},

        { &hf_fefd_sent_through_interface,
          { "Sent through Interface",  "fefd.sent_through_interface", FT_STRING, BASE_NONE, NULL, 0x0,
            NULL, HFILL }},

        { &hf_fefd_data,
          { "Data",  "fefd.data", FT_BYTES, BASE_NONE, 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;

    fefd_handle = create_dissector_handle(dissect_fefd, proto_fefd);
    dissector_add_uint("llc.force10_pid", 0x0111, fefd_handle);
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 4
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 *
 * vi: set shiftwidth=4 tabstop=8 expandtab:
 * :indentSize=4:tabSize=8:noTabs=true:
 */
