wireshark/epan/dissectors/packet-bofl.c

/* packet-bofl.c
 * Routines for Wellfleet BOFL dissection
 * Wellfleet -> Baynetworks -> Nortel -> Avaya -> Extremenetworks
 * Protocol is now called Simple Loop Protection Protocol (SLPP)
 * Author: Endoh Akira (endoh@netmarks.co.jp)
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@unicom.net>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * The following information was copied from
 * http://web.archive.org/web/20150608035209/http://www.protocols.com/pbook/bridge.htm#WellfleetBOFL
 *
 * The Wellfleet Breath of Life (BOFL) protocol is used as a line sensing
 * protocol on:
 *
 * - Ethernet LANs to detect transmitter jams.
 * - Synchronous lines running WFLT STD protocols to determine if the line
 *   is up.
 * - Dial backup PPP lines.
 *
 * The frame format of Wellfleet BOFL is shown following the Ethernet header
 * in the following illustration:
 *
 *  Destination   Source    8102    PDU   Sequence   Padding
 *       6           6        2      4       4       n bytes
 */

/* From the above link:
 *
 * Wellfleet BOFL
 *
 * The Wellfleet Breath of Life (BOFL) protocol is used as a line sensing protocol on:
 *
 * Ethernet LANs to detect transmitter jams.
 * Synchronous lines running WFLT STD protocols to determine if the line is up.
 * Dial backup PPP lines.
 * The frame format of Wellfleet BOFL is shown following the Ethernet header in the following illustration:
 *
 * Destination | Source |8102 | PDU | Sequence | Padding
 *  6          |  6     | 2   |  4  |  4       | n bytes
 * <-------------------------->
 *       Ethernet Header
 *
 * 8102
 * EtherType (0x8102 for Wellfleet BOFL frames).
 *
 * PDU
 * PDU field normally equals 0x01010000, but may equal 0x01011111 in some new releases on synchronous links.
 *
 * Sequence
 * 4-byte sequence field is an incremental counter.
 *
 * Padding
 * Padding to fill out the frame to 64 bytes.
 */

#include "config.h"

#include <epan/packet.h>

#define ETHER_TYPE_SLPP 0x8102
#define BOFL_MIN_LEN    8

void proto_register_bofl(void);
void proto_reg_handoff_bofl(void);

/* Initialize the protocol and registered fields */
static int proto_bofl       = -1;
static int hf_bofl_pdu      = -1;
static int hf_bofl_sequence = -1;
static int hf_bofl_padding  = -1;

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

/* Code to actually dissect the packets */
static int
dissect_bofl(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
    proto_item  *ti;
    proto_tree  *bofl_tree;
    gint        len;
    guint32     pdu, sequence;

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "BOFL");

    col_clear(pinfo->cinfo, COL_INFO);

    ti = proto_tree_add_item(tree, proto_bofl, tvb, 0, -1, ENC_NA);
    bofl_tree = proto_item_add_subtree(ti, ett_bofl);

    pdu = tvb_get_ntohl(tvb, 0);
    col_add_fstr(pinfo->cinfo, COL_INFO,
        "PDU: 0x%08x", pdu);
    proto_tree_add_uint(bofl_tree, hf_bofl_pdu, tvb, 0, 4, pdu);

    sequence = tvb_get_ntohl(tvb, 4);

    col_append_fstr(pinfo->cinfo, COL_INFO,
        " Sequence: %u", sequence);

    proto_tree_add_uint(bofl_tree, hf_bofl_sequence, tvb, 4, 4, sequence);

    len = tvb_reported_length_remaining(tvb, 8);
    if (len > 0)
        proto_tree_add_item(bofl_tree, hf_bofl_padding, tvb, 8, -1, ENC_NA);

    return tvb_captured_length(tvb);
}


void
proto_register_bofl(void)
{
    static hf_register_info hf[] = {
        { &hf_bofl_pdu,
          { "PDU", "bofl.pdu",
            FT_UINT32, BASE_HEX, NULL, 0,
            "PDU; normally equals 0x01010000 or 0x01011111", HFILL }
        },
        { &hf_bofl_sequence,
          { "Sequence", "bofl.sequence",
            FT_UINT32, BASE_DEC, NULL, 0,
            "incremental counter", HFILL }
        },
        { &hf_bofl_padding,
          { "Padding", "bofl.padding",
            FT_BYTES, BASE_NONE, NULL, 0,
            NULL, HFILL }
        }
    };

    static gint *ett[] = {
        &ett_bofl,
    };

    proto_bofl = proto_register_protocol("Wellfleet Breath of Life",
                                         "BOFL", "bofl");
    proto_register_field_array(proto_bofl, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
}


void
proto_reg_handoff_bofl(void)
{
    dissector_handle_t bofl_handle;

    bofl_handle = create_dissector_handle(dissect_bofl, proto_bofl);
    dissector_add_uint("ethertype", ETHER_TYPE_SLPP, bofl_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:
 */