/* packet-cisco-metadata.c

 * Routines for dissection of Cisco's MetaData protocol.

 * draft-smith-kandula-sxp

 * Copyright 2013 by Vaibhav Katkade (vkatkade[AT]cisco.com)

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

#include "config.h"

#include <epan/packet.h>

#include <epan/etypes.h>

#if 0

#include "packet-ieee8023.h"

#endif

void proto_register_cmd(void);

void proto_reg_handoff_cmd(void);

static dissector_handle_t cmd_eth_handle;

static dissector_handle_t cmd_gre_handle;

static dissector_handle_t ethertype_handle;

static dissector_table_t gre_dissector_table;

static int proto_cmd;

static int hf_cmd_version;

static int hf_cmd_length;

static int hf_cmd_options;

static int hf_cmd_sgt;

static int hf_eth_type;

static int hf_cmd_trailer;

static int ett_cmd;

static int

dissect_cmd_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

    uint16_t encap_proto;

    ethertype_data_t ethertype_data;

    proto_tree *cmd_tree = NULL;

    int offset = 0;

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

    col_clear(pinfo->cinfo, COL_INFO);

    if (tree) {

        proto_item *ti = proto_tree_add_item(tree, proto_cmd, tvb, 0, 8, ENC_NA);

        cmd_tree = proto_item_add_subtree(ti, ett_cmd);

        proto_tree_add_item(cmd_tree, hf_cmd_version, tvb, offset, 1, ENC_BIG_ENDIAN);

        offset += 1;

        proto_tree_add_item(cmd_tree, hf_cmd_length, tvb, offset, 1, ENC_BIG_ENDIAN);

        offset += 1;

        proto_tree_add_item(cmd_tree, hf_cmd_options, tvb, offset, 2, ENC_BIG_ENDIAN);

        offset += 2;

        proto_tree_add_item(cmd_tree, hf_cmd_sgt, tvb, offset, 2, ENC_BIG_ENDIAN);

        /*offset += 2;*/

    }

    encap_proto = tvb_get_ntohs(tvb, 6);

/* This Logic to identify and decode IEEE 802.3 frames is not working correctly. Carry over code from packet-vlan.c

 * Commenting it out for now will display as Unknown for L2 control frames instead of showing a wrong decode.

 */

#if 0

    if (encap_proto <= IEEE_802_3_MAX_LEN) {

        bool is_802_2 = true;

        /* Don't throw an exception for this check (even a BoundsError) */

        if (tvb_captured_length_remaining(tvb, 4) >= 2) {

            if (tvb_get_ntohs(tvb, 4) == 0xffff)

                is_802_2 = false;

        }

        dissect_802_3(encap_proto, is_802_2, tvb, 4, pinfo, tree, cmd_tree, hf_eth_type, hf_cmd_trailer, 0);

    } else {

#endif

    proto_tree_add_uint(cmd_tree, hf_eth_type, tvb, 6, 2, encap_proto);

    ethertype_data.etype = encap_proto;

    ethertype_data.payload_offset = 8;

    ethertype_data.fh_tree = cmd_tree;

    ethertype_data.trailer_id = hf_cmd_trailer;

    ethertype_data.fcs_len = 0;

    call_dissector_with_data(ethertype_handle, tvb, pinfo, tree, &ethertype_data);

    return tvb_captured_length(tvb);

}

static int

dissect_cmd_gre(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

    proto_item *ti = NULL;

    proto_tree *cmd_tree = NULL;

    uint16_t encap_proto;

    tvbuff_t *next_tvb;

    int offset = 0;

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

    col_clear(pinfo->cinfo, COL_INFO);

    if (tree) {

        ti = proto_tree_add_item(tree, proto_cmd, tvb, 0, 6, ENC_NA);

        cmd_tree = proto_item_add_subtree(ti, ett_cmd);

    }

    encap_proto = tvb_get_ntohs(tvb, 0);

    proto_tree_add_item(cmd_tree, hf_eth_type, tvb, offset, 2, ENC_BIG_ENDIAN);

    offset += 2;

    proto_tree_add_item(cmd_tree, hf_cmd_version, tvb, offset, 1, ENC_BIG_ENDIAN);

    offset += 1;

    proto_tree_add_item(cmd_tree, hf_cmd_length, tvb, offset, 1, ENC_BIG_ENDIAN);

    offset += 1;

    proto_tree_add_item(cmd_tree, hf_cmd_options, tvb, offset, 2, ENC_BIG_ENDIAN);

    offset += 2;

    proto_tree_add_item(cmd_tree, hf_cmd_sgt, tvb, offset, 2, ENC_BIG_ENDIAN);

    offset += 2;

    next_tvb = tvb_new_subset_remaining(tvb, offset);

    if (!dissector_try_uint(gre_dissector_table, encap_proto, next_tvb, pinfo, tree))

        call_data_dissector(next_tvb, pinfo, tree);

    return tvb_captured_length(tvb);

}

void

proto_register_cmd(void)

{

    static hf_register_info hf[] = {

        { &hf_cmd_version,

            { "Version", "cmd.version", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }

        },

        { &hf_cmd_length,

            { "Length", "cmd.length", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }

        },

        { &hf_cmd_options,

            { "Options", "cmd.options", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL }

        },

        { &hf_cmd_sgt,

            { "SGT", "cmd.sgt", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }

        },

        { &hf_eth_type,

            { "Type", "cmd.type", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0, NULL, HFILL }

        },

        { &hf_cmd_trailer,

            { "Trailer", "cmd.trailer", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }

        },

    };

    static int *ett[] = {

        &ett_cmd

    };

    proto_cmd = proto_register_protocol("Cisco MetaData", "Cisco MetaData", "cmd");

    proto_register_field_array(proto_cmd, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    cmd_eth_handle = register_dissector("cmd.eth", dissect_cmd_eth, proto_cmd);

    cmd_gre_handle = register_dissector("cmd.gre", dissect_cmd_gre, proto_cmd);

}

void

proto_reg_handoff_cmd(void)

{

    ethertype_handle = find_dissector_add_dependency("ethertype", proto_cmd);

    gre_dissector_table = find_dissector_table("gre.proto");

    dissector_add_uint("ethertype", ETHERTYPE_CMD, cmd_eth_handle);

    dissector_add_uint("gre.proto", ETHERTYPE_CMD, cmd_gre_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:

 */