/* packet-trel.c

 * Routines for TREL packet dissection

 * Copyright 2004, Pranay Nagpure  - <pranay.dilip@graniteriverlabs.in>

 *

 * 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 "packet-ieee802154.h"

#include <epan/wmem_scopes.h>

#include <epan/packet_info.h>

#include <epan/proto_data.h>

#include <epan/proto.h>

#include <packet-mle.h>

#include <packet-6lowpan.h>

#include <epan/expert.h>

#include<wsutil/wsgcrypt.h>

#define TREL_PORT 38196

#define  TREL_TYPE_BROADCAST 0

#define TREL_TYPE_UNICAST    1

#define TREL_TYPE_ACK        2

static dissector_handle_t trel_handle;

static int hf_trel_version;

static int hf_trel_rsv;

static int hf_trel_ack;

static int hf_trel_type;

static int hf_trel_channel;

static int hf_802154_dest_panid;

static int hf_trel_source_addr;

static int hf_trel_destination_addr;

static int hf_trel_packetno;

static int proto_trel;

static int ett_trel;

static int ett_trel_hdr;

void proto_register_trel(void);

static const value_string trel_command_vals[] = {

    { TREL_TYPE_BROADCAST,                "TREL Advertisement" },

    { TREL_TYPE_UNICAST,                  "TREL Unicast Response" },

    { TREL_TYPE_ACK,                      "TREL Acknowledgement"},

    { 0, NULL}

};

static int

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

{

    proto_tree* volatile trel_tree = NULL, * volatile trel_hdr_tree;

    proto_item* volatile proto_root = NULL;

    uint32_t type;

    unsigned                offset = 0;

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

    col_clear(pinfo->cinfo, COL_INFO);

    proto_root = proto_tree_add_item(tree, proto_trel, tvb, 0, tvb_reported_length(tvb), ENC_NA);

    trel_tree = proto_item_add_subtree(proto_root, ett_trel);

    //add header subtree

    trel_hdr_tree = proto_tree_add_subtree(trel_tree, tvb, 0, 4, ett_trel_hdr, NULL, "Header");

    proto_tree_add_item(trel_hdr_tree, hf_trel_version, tvb, offset, 1, ENC_NA);

    proto_tree_add_item(trel_hdr_tree, hf_trel_rsv, tvb, offset, 1, ENC_NA);

    proto_tree_add_item(trel_hdr_tree, hf_trel_ack, tvb, offset, 1, ENC_NA);

    proto_tree_add_item_ret_uint(trel_hdr_tree, hf_trel_type, tvb, offset, 1, ENC_NA, &type);

    col_add_str(pinfo->cinfo, COL_INFO, val_to_str(pinfo->pool, type, trel_command_vals, "Unknown (%x)"));

    ++offset;

    proto_tree_add_item(trel_hdr_tree, hf_trel_channel, tvb, offset, 1, ENC_NA);

    ++offset;

    proto_tree_add_item(trel_hdr_tree, hf_802154_dest_panid, tvb, offset, 2, ENC_BIG_ENDIAN);

    offset += 2;

    proto_tree_add_item(trel_hdr_tree, hf_trel_packetno, tvb, offset, 4, ENC_BIG_ENDIAN);

    offset += 4;

    proto_tree_add_item(trel_hdr_tree, hf_trel_source_addr, tvb, offset, 8, ENC_BIG_ENDIAN);

    offset += 8;

    if (type)

    {

        proto_tree_add_item(trel_hdr_tree, hf_trel_destination_addr, tvb, offset, 8, ENC_BIG_ENDIAN);

        offset += 8;

    }

    dissector_handle_t frame_handle = find_dissector("wpan_nofcs");

    tvbuff_t* payload = tvb_new_subset_remaining(tvb, offset);

    if (tvb_reported_length(payload))

        call_dissector(frame_handle, payload, pinfo, trel_tree);

    return tvb_captured_length(tvb);

}

// below code is added to replace mdns dissector registration

static bool

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

{

    if ((tvb_captured_length(tvb)) < 16 ) {

        return false;

    }

    uint8_t first = tvb_get_uint8(tvb, 0);

    if ((first & 0xE0) != 0)

        return false;

    if (pinfo->srcport == pinfo->destport)      return false;

    dissect_trel(tvb, pinfo, tree, data);

    return true;

}

void

proto_register_trel(void)

{

    static hf_register_info hf[] = {

        { &hf_trel_version,

          { "TREL version",

            "trel.ver",

            FT_UINT8, BASE_DEC, NULL, 0xE0,

            "The TREL protocol version",

            HFILL

          }

        },

        { &hf_trel_rsv,

          { "TREL reserved bit",

            "trel.rsv",

            FT_UINT8, BASE_DEC, NULL, 0x18,

            "The TREL reserved bit",

            HFILL

          }

        },

        { &hf_trel_ack,

          { "TREL acknowledgement",

            "trel.ack",

            FT_UINT8, BASE_DEC, NULL, 0x4,

            "The TREL acknowledgement",

            HFILL

          }

        },

        { &hf_trel_type,

          { "TREL type",

            "trel.type",

            FT_UINT8, BASE_DEC, NULL, 0x3,

            "The TREL type",

            HFILL

          }

        },

        { &hf_trel_channel,

          { "TREL channel",

            "trel.channel",

            FT_UINT8, BASE_DEC, NULL, 0x0,

            "The TREL channel",

            HFILL

          }

        },

        { &hf_802154_dest_panid,

          { "TREL 802.15.4 Dest Pan ID",

            "trel.panID",

            FT_UINT16, BASE_DEC, NULL, 0x0,

            "The TREL  802.15.4 Dest Pan ID",

            HFILL

          }

        },

        { &hf_trel_packetno,

          { "TREL packet number",

            "trel.packetno",

            FT_UINT32, BASE_DEC, NULL, 0x0,

            "The TREL  packet number",

            HFILL

          }

        },

        { &hf_trel_source_addr,

          { "TREL Src Address",

             "trel.source_addr",

             FT_EUI64, BASE_NONE, NULL, 0x0,

             "Source address",

             HFILL

          }

        },

        { &hf_trel_destination_addr,

          { "TREL Dest Address",

            "trel.destination_addr",

            FT_EUI64, BASE_NONE, NULL, 0x0,

            "Destination address",

            HFILL

          }

        }

    };

    static int* ett[] = {

      &ett_trel,

      &ett_trel_hdr

    };

    proto_trel = proto_register_protocol("TREL Protocol", "TREL", "trel");

    proto_register_field_array(proto_trel, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    trel_handle = register_dissector("trel", dissect_trel, proto_trel);

}

void

proto_reg_handoff_trel(void)

{

    //heur dissector is disabled as it not strong enough

    //dissector_add_uint("udp.port", TREL_PORT, trel_handle);

    dissector_add_uint_with_preference("udp.port", 0, trel_handle);

    heur_dissector_add("udp", dissect_trel_heur, "TREL over UDP", "trel_udp", proto_trel, HEURISTIC_DISABLE);

}