/* packet-mactelnet.c

 * Routines for MAC-Telnet dissection

 * Copyright 2010, Haakon Nessjoen <haakon.nessjoen@gmail.com>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

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

 */

/*

 * Thanks to "omniflux" for dissecting the protocol by hand before me.

 * http://www.omniflux.com/devel/mikrotik/Mikrotik_MAC_Telnet_Procotol.txt

 */

#include "config.h"

#include <epan/packet.h>

#include <epan/to_str.h>

void proto_register_mactelnet(void);

void proto_reg_handoff_mactelnet(void);

/* Initialize the protocol and registered fields */

static int proto_mactelnet;

static int hf_mactelnet_control_packet;

static int hf_mactelnet_type;

static int hf_mactelnet_protocolver;

static int hf_mactelnet_source_mac;

static int hf_mactelnet_destination_mac;

static int hf_mactelnet_session_id;

static int hf_mactelnet_client_type;

static int hf_mactelnet_databytes;

static int hf_mactelnet_datatype;

static int hf_mactelnet_control;

static int hf_mactelnet_control_length;

static int hf_mactelnet_control_encryption_key;

static int hf_mactelnet_control_password;

static int hf_mactelnet_control_username;

static int hf_mactelnet_control_terminal;

static int hf_mactelnet_control_width;

static int hf_mactelnet_control_height;

#define MACTELNET_UDP_PORT      20561 /* Not IANA registered */

/* Control packet definition */

static const uint32_t control_packet = 0x563412FF;

/* Initialize the subtree pointers */

static int ett_mactelnet;

static int ett_mactelnet_control;

/* Packet types */

static const value_string packettypenames[] = {

    {   0, "Start session" },

    {   1, "Data" },

    {   2, "Acknowledge" },

    {   4, "Ping request" },

    {   5, "Ping response" },

    { 255, "End session" },

    { 0, NULL }

};

/* Known client types */

static const value_string clienttypenames[] = {

    { 0x0015, "MAC Telnet" },

    { 0x0f90, "Winbox" },

    { 0, NULL }

};

/* Known control-packet types */

static const value_string controlpackettypenames[] = {

    { 0, "Begin authentication" },

    { 1, "Encryption key" },

    { 2, "Password" },

    { 3, "Username" },

    { 4, "Terminal type" },

    { 5, "Terminal width" },

    { 6, "Terminal height" },

    { 9, "End authentication" },

    { 0, NULL }

};

static int

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

{

    proto_item *mactelnet_item;

    proto_tree *mactelnet_tree;

    proto_item *mactelnet_control_item;

    proto_tree *mactelnet_control_tree;

    int         foundping   = -1;

    int         foundclient = -1;

    int         foundserver = -1;

    uint16_t    type;

    /* Check that there's enough data */

    if (tvb_captured_length(tvb) < 18)

        return 0;

    /*  Get the type byte */

    type = tvb_get_uint8(tvb, 1);

    if ((type == 4) || (type == 5)) { /* Ping */

        foundping = 1;

    } else {

        int i = 0;

        while (clienttypenames[i].strptr != NULL) {

            if (tvb_get_ntohs(tvb, 14) == clienttypenames[i].value) {

                foundserver = i;

                break;

            }

            if (tvb_get_ntohs(tvb, 16) == clienttypenames[i].value) {

                foundclient = i;

                break;

            }

            i++;

        }

    }

    /* Not a mactelnet packet */

    if ((foundping < 0) && (foundclient < 0) && (foundserver < 0)) {

        return 0;

    }

    /* Make entries in Protocol column and Info column on summary display */

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "MAC-Telnet");

    col_add_fstr(pinfo->cinfo, COL_INFO, "%s > %s Direction: %s Type: %s",

                    tvb_ether_to_str(pinfo->pool, tvb, 2),

                    tvb_ether_to_str(pinfo->pool, tvb, 8),

                    ((foundclient >= 0) || (type == 4) ? "Client->Server" : "Server->Client" ),

                    val_to_str(pinfo->pool, type, packettypenames, "Unknown Type:0x%02x")

        );

    if (tree) {

        uint32_t offset = 0;

        /* create display subtree for the protocol */

        mactelnet_item = proto_tree_add_item(tree, proto_mactelnet, tvb, 0, -1, ENC_NA);

        mactelnet_tree = proto_item_add_subtree(mactelnet_item, ett_mactelnet);

        /* ver(1) */

        proto_tree_add_item(mactelnet_tree, hf_mactelnet_protocolver, tvb, offset, 1, ENC_NA);

        offset += 1;

        /* ptype(1) */

        proto_tree_add_item(mactelnet_tree, hf_mactelnet_type, tvb, offset, 1, ENC_NA);

        offset += 1;

        /* saddr(6) */

        proto_tree_add_item(mactelnet_tree, hf_mactelnet_source_mac, tvb, offset, 6, ENC_NA);

        offset += 6;

        /* dstaddr(6) */

        proto_tree_add_item(mactelnet_tree, hf_mactelnet_destination_mac, tvb, offset, 6, ENC_NA);

        offset += 6;

        if (foundserver >= 0) {

            /* Server to client */

            /* sessionid(2) */

            proto_tree_add_item(mactelnet_tree, hf_mactelnet_session_id, tvb, offset+2, 2, ENC_BIG_ENDIAN);

            offset += 2;

            /* clienttype(2) */

            proto_tree_add_item(mactelnet_tree, hf_mactelnet_client_type, tvb, offset-2, 2, ENC_BIG_ENDIAN);

            offset += 2;

        } else if (foundclient >= 0) {

            /* Client to server */

            /* sessionid(2) */

            proto_tree_add_item(mactelnet_tree, hf_mactelnet_session_id, tvb, offset, 2, ENC_BIG_ENDIAN);

            offset += 2;

            /* clienttype(2) */

            proto_tree_add_item(mactelnet_tree, hf_mactelnet_client_type, tvb, offset, 2, ENC_BIG_ENDIAN);

            offset += 2;

        } else if (foundping >= 0) {

            /* Skip empty data */

            offset += 4;

        }

        if (foundping < 0) {

            /* counter(4) */

            proto_tree_add_item(mactelnet_tree, hf_mactelnet_databytes, tvb, offset, 4, ENC_BIG_ENDIAN);

            offset += 4;

        }

        /* Data packets only */

        if (type == 1) {

            while(tvb_reported_length_remaining(tvb, offset) > 0) {

                if ((tvb_reported_length_remaining(tvb, offset) > 4) && (tvb_get_ntohl(tvb, offset) == control_packet)) {

                    uint8_t datatype;

                    uint32_t datalength;

                    /* Add subtree for control packet */

                    mactelnet_control_item = proto_tree_add_item(mactelnet_tree, hf_mactelnet_control, tvb, offset, -1, ENC_NA);

                    mactelnet_control_tree = proto_item_add_subtree(mactelnet_control_item, ett_mactelnet);

                    /* Control packet magic number (4) */

                    proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_packet, tvb, offset, 4, ENC_BIG_ENDIAN);

                    offset += 4;

                    /* Control packet type (1) */

                    proto_tree_add_item_ret_uint8(mactelnet_control_tree, hf_mactelnet_datatype, tvb, offset, 1, ENC_NA, &datatype);

                    offset += 1;

                    /* Control packet length (4) */

                    proto_tree_add_item_ret_uint(mactelnet_control_tree, hf_mactelnet_control_length, tvb, offset, 4, ENC_BIG_ENDIAN, &datalength);

                    offset += 4;

                    switch (datatype) {

                        case 1: /* Encryption Key */

                            proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_encryption_key, tvb, offset, datalength, ENC_NA);

                            break;

                        case 2: /* Password */

                            proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_password, tvb, offset, datalength, ENC_NA);

                            break;

                        case 3: /* Username */

                            proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_username, tvb, offset, datalength, ENC_ASCII);

                            break;

                        case 4: /* Terminal type */

                            proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_terminal, tvb, offset, datalength, ENC_ASCII);

                            break;

                        case 5: /* Terminal width */

                            proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_width, tvb, offset, 2, ENC_LITTLE_ENDIAN);

                            break;

                        case 6: /* Terminal height */

                            proto_tree_add_item(mactelnet_control_tree, hf_mactelnet_control_height, tvb, offset, 2, ENC_LITTLE_ENDIAN);

                            break;

                        case 9: /* End authentication (no data) */

                            break;

                    }

                    proto_item_set_len (mactelnet_control_item, datalength + 9);

                    offset += datalength;

                } else {

                    /* Data packet, let wireshark handle it */

                    tvbuff_t *next_client = tvb_new_subset_remaining(tvb, offset);

                    return call_data_dissector(next_client, pinfo, mactelnet_tree);

                }

            }

        } else if ((type == 4) || (type == 5)) {

            /* Data packet, let wireshark handle it */

            tvbuff_t *next_client = tvb_new_subset_remaining(tvb, offset);

            return call_data_dissector(next_client, pinfo, mactelnet_tree);

        }

    }

    return tvb_reported_length(tvb);

}

void

proto_register_mactelnet(void)

{

    static hf_register_info hf[] = {

        { &hf_mactelnet_control_packet,

          { "Control Packet Magic Number", "mactelnet.control_packet",

            FT_UINT32, BASE_HEX, NULL, 0x0,

            NULL, HFILL }

        },

        { &hf_mactelnet_type,

          { "Type", "mactelnet.type",

            FT_UINT8, BASE_DEC, VALS(packettypenames), 0x0,

            "Packet Type", HFILL }

        },

        { &hf_mactelnet_protocolver,

          { "Protocol Version", "mactelnet.protocol_version",

            FT_UINT8, BASE_DEC, NULL, 0x0,

            NULL, HFILL }

        },

        { &hf_mactelnet_source_mac,

          { "Source MAC", "mactelnet.source_mac",

            FT_ETHER, BASE_NONE, NULL , 0x0,

            NULL, HFILL }

        },

        { &hf_mactelnet_destination_mac,

          { "Destination MAC", "mactelnet.destination_mac",

            FT_ETHER, BASE_NONE, NULL , 0x0,

            NULL, HFILL }

        },

        { &hf_mactelnet_session_id,

          { "Session ID", "mactelnet.session_id",

            FT_UINT16, BASE_HEX, NULL , 0x0,

            "Session ID for this connection", HFILL }

        },

        { &hf_mactelnet_client_type,

          { "Client Type", "mactelnet.client_type",

            FT_UINT16, BASE_HEX, VALS(clienttypenames) , 0x0,

            NULL, HFILL }

        },

        { &hf_mactelnet_databytes,

          { "Session Data Bytes", "mactelnet.session_bytes",

            FT_UINT32, BASE_DEC, NULL , 0x0,

            "Session data bytes received", HFILL }

        },

        { &hf_mactelnet_datatype,

          { "Data Packet Type", "mactelnet.data_type",

            FT_UINT8, BASE_HEX, VALS(controlpackettypenames) , 0x0,

            NULL, HFILL }

        },

        { &hf_mactelnet_control,

          { "Control Packet", "mactelnet.control",

            FT_NONE, BASE_NONE, NULL , 0x0,

            NULL, HFILL }

        },

        { &hf_mactelnet_control_length,

          { "Control Data Length", "mactelnet.control_length",

            FT_UINT32, BASE_DEC, NULL , 0x0,

            "Control packet length", HFILL }

        },

        { &hf_mactelnet_control_encryption_key,

          { "Encryption Key", "mactelnet.control_encryptionkey",

            FT_BYTES, BASE_NONE, NULL , 0x0,

            "Login encryption key", HFILL }

        },

        { &hf_mactelnet_control_password,

          { "Password MD5", "mactelnet.control_password",

            FT_BYTES, BASE_NONE, NULL , 0x0,

            "Null padded MD5 password", HFILL }

        },

        { &hf_mactelnet_control_username,

          { "Username", "mactelnet.control_username",

            FT_STRING, BASE_NONE, NULL , 0x0,

            NULL, HFILL }

        },

        { &hf_mactelnet_control_terminal,

          { "Terminal Type", "mactelnet.control_terminaltype",

            FT_STRING, BASE_NONE, NULL , 0x0,

            NULL, HFILL }

        },

        { &hf_mactelnet_control_width,

          { "Terminal Width", "mactelnet.control_width",

            FT_UINT16, BASE_DEC, NULL , 0x0,

            NULL, HFILL }

        },

        { &hf_mactelnet_control_height,

          { "Terminal Height", "mactelnet.control_height",

            FT_UINT16, BASE_DEC, NULL , 0x0,

            NULL, HFILL }

        }

    };

    /* Setup protocol subtree array */

    static int *ett[] = {

        &ett_mactelnet,

        &ett_mactelnet_control,

    };

    /* Register the protocol name and description */

    proto_mactelnet = proto_register_protocol ("MikroTik MAC-Telnet Protocol", "MAC-Telnet", "mactelnet");

    register_dissector("mactelnet", dissect_mactelnet, proto_mactelnet);

    /* Required function calls to register the header fields and subtrees used */

    proto_register_field_array (proto_mactelnet, hf, array_length (hf));

    proto_register_subtree_array (ett, array_length (ett));

}

void

proto_reg_handoff_mactelnet(void)

{

    dissector_add_uint_with_preference("udp.port", MACTELNET_UDP_PORT, find_dissector("mactelnet"));

}

/*

 * 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:

 */