/* packet-ms-mms.c

 *

 * Routines for MicroSoft MMS (Microsoft Media Server) message dissection

 *

 * See

 *

 *    https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-mmsp

 *

 * for the [MS-MMSP] specification.

 *

 * Copyright 2005

 * Written by Martin Mathieson

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

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

 */

/* Information sources:

 * sdp.ppona.com

 */

#include "config.h"

#include <stdio.h>      /* for sscanf() */

#include <epan/packet.h>

#include <epan/conversation.h>

#include <epan/strutil.h>

static dissector_handle_t msmms_handle;

static int                proto_msmms;

/* Command fields */

static int    hf_msmms_command;

static int    hf_msmms_command_common_header;

/* static int    hf_msmms_command_version; */

static int    hf_msmms_command_signature;

static int    hf_msmms_command_length;

static int    hf_msmms_command_protocol_type;

static int    hf_msmms_command_length_remaining;

static int    hf_msmms_command_sequence_number;

static int    hf_msmms_command_timestamp;

static int    hf_msmms_command_length_remaining2;

static int    hf_msmms_command_to_client_id;

static int    hf_msmms_command_to_server_id;

static int    hf_msmms_command_direction;

static int    hf_msmms_command_prefix1;

static int    hf_msmms_command_prefix1_error;

static int    hf_msmms_command_prefix1_command_level;

static int    hf_msmms_command_prefix2;

static int    hf_msmms_command_client_transport_info;

static int    hf_msmms_command_client_player_info;

static int    hf_msmms_command_server_version;

static int    hf_msmms_command_tool_version;

static int    hf_msmms_command_update_url;

static int    hf_msmms_command_password_type;

static int    hf_msmms_command_server_version_length;

static int    hf_msmms_command_tool_version_length;

static int    hf_msmms_command_update_url_length;

static int    hf_msmms_command_password_type_length;

static int    hf_msmms_command_number_of_words;

static int    hf_msmms_command_client_id;

static int    hf_msmms_command_server_file;

static int    hf_msmms_command_result_flags;

static int    hf_msmms_command_broadcast_indexing;

static int    hf_msmms_command_broadcast_liveness;

static int    hf_msmms_command_recorded_media_length;

static int    hf_msmms_command_media_packet_length;

static int    hf_msmms_command_strange_string;

static int    hf_msmms_command_stream_structure_count;

static int    hf_msmms_stream_selection_flags;

static int    hf_msmms_stream_selection_stream_id;

static int    hf_msmms_stream_selection_action;

static int    hf_msmms_command_header_packet_id_type;

/* Data fields */

static int    hf_msmms_data;

static int    hf_msmms_data_sequence_number;

static int    hf_msmms_data_packet_id_type;

static int    hf_msmms_data_udp_sequence;

static int    hf_msmms_data_tcp_flags;

static int    hf_msmms_data_packet_length;

static int    hf_msmms_data_header_id;

static int    hf_msmms_data_client_id;

static int    hf_msmms_data_command_id;

static int    hf_msmms_data_packet_to_resend;

static int    hf_msmms_data_timing_pair;

static int    hf_msmms_data_timing_pair_seqno;

static int    hf_msmms_data_timing_pair_flags;

static int    hf_msmms_data_timing_pair_id;

static int    hf_msmms_data_timing_pair_flag;

static int    hf_msmms_data_timing_pair_packet_length;

static int    hf_msmms_data_unparsed;

/* Subtrees */

static int    ett_msmms_command;

static int    ett_msmms_command_common_header;

static int    ett_msmms_data;

static int    ett_msmms_data_timing_packet_pair;

#define MSMMS_PORT 1755

/* Known command IDs */

#define SERVER_COMMAND_CONNECT_INFO                0x01

#define SERVER_COMMAND_TRANSPORT_INFO              0x02

#define SERVER_COMMAND_PROTOCOL_SELECTION_ERROR    0x03

#define SERVER_COMMAND_REQUEST_SERVER_FILE         0x05

#define SERVER_COMMAND_START_SENDING_FROM          0x07

#define SERVER_COMMAND_STOP_BUTTON_PRESSED         0x09

#define SERVER_COMMAND_CANCEL_PROTOCOL             0x0d

#define SERVER_COMMAND_HEADER_REQUEST              0x15

#define SERVER_COMMAND_TIMING_TEST_DATA_REQUEST    0x18

#define SERVER_COMMAND_AUTHENTICATION_RESPONSE     0x1a

#define SERVER_COMMAND_NETWORK_TIMER_TEST_RESPONSE 0x1b

#define SERVER_COMMAND_ACTIVATE_FF_RW_BUTTONS      0x28

#define SERVER_COMMAND_HAVE_STOPPED_PLAYING        0x30

#define SERVER_COMMAND_LOCAL_COMPUTER_DETAILS      0x32

#define SERVER_COMMAND_MEDIA_STREAM_MBR_SELECTOR   0x33

static const value_string to_server_command_vals[] =

{

    { SERVER_COMMAND_CONNECT_INFO,                "Connect info" },

    { SERVER_COMMAND_TRANSPORT_INFO,              "Transport info" },

    { SERVER_COMMAND_PROTOCOL_SELECTION_ERROR,    "Protocol selection error" },

    { SERVER_COMMAND_REQUEST_SERVER_FILE,         "Request server file"  },

    { SERVER_COMMAND_START_SENDING_FROM,          "Start sending from:" },

    { SERVER_COMMAND_STOP_BUTTON_PRESSED,         "Stop button pressed" },

    { SERVER_COMMAND_CANCEL_PROTOCOL,             "Cancel protocol" },

    { SERVER_COMMAND_HEADER_REQUEST,              "Header request" },

    { SERVER_COMMAND_TIMING_TEST_DATA_REQUEST,    "Timing test data request" },

    { SERVER_COMMAND_AUTHENTICATION_RESPONSE,     "Authentication response" },

    { SERVER_COMMAND_NETWORK_TIMER_TEST_RESPONSE, "Network timer test response" },

    { SERVER_COMMAND_ACTIVATE_FF_RW_BUTTONS,      "Activate FF/Rewind buttons" },

    { SERVER_COMMAND_HAVE_STOPPED_PLAYING,        "Have stopped playing" },

    { SERVER_COMMAND_LOCAL_COMPUTER_DETAILS,      "Local computer details" },

    { SERVER_COMMAND_MEDIA_STREAM_MBR_SELECTOR,   "Media Stream MBR selector" },

    { 0,      NULL }

};

#define CLIENT_COMMAND_SERVER_INFO                0x01

#define CLIENT_COMMAND_TRANSPORT_INFO_ACK         0x02

#define CLIENT_COMMAND_PROTOCOL_SELECTION_ERROR   0x03

#define CLIENT_COMMAND_SENDING_MEDIA_FILE_NOW     0x05

#define CLIENT_COMMAND_MEDIA_DETAILS              0x06

#define CLIENT_COMMAND_FF_RW                      0x0a

#define CLIENT_COMMAND_SENDING_HEADER_RESPONSE    0x11

#define CLIENT_COMMAND_TIMING_TEST_DATA_RESPONSE  0x15

#define CLIENT_COMMAND_TIMING_TEST_DATA_REQUEST   0x18

#define CLIENT_COMMAND_AUTHENTICATION_CHALLENGE   0x1a

#define CLIENT_COMMAND_NETWORK_TIMER_TEST         0x1b

#define CLIENT_COMMAND_END_OF_MEDIA_STREAM        0x1e

#define CLIENT_COMMAND_MEDIA_CHANGING_INDICATOR   0x20

#define CLIENT_COMMAND_STREAM_SELECTION_INDICATOR 0x21

static const value_string to_client_command_vals[] =

{

    { CLIENT_COMMAND_SERVER_INFO,                "Server info" },

    { CLIENT_COMMAND_TRANSPORT_INFO_ACK,         "Transport info ack" },

    { CLIENT_COMMAND_PROTOCOL_SELECTION_ERROR,   "Protocol selection error" },

    { CLIENT_COMMAND_SENDING_MEDIA_FILE_NOW,     "Sending media file now"  },

    { CLIENT_COMMAND_MEDIA_DETAILS,              "Media details"  },

    { CLIENT_COMMAND_FF_RW,                      "FF/Rewind" },

    { CLIENT_COMMAND_SENDING_HEADER_RESPONSE,    "Sending header response" },

    { CLIENT_COMMAND_TIMING_TEST_DATA_RESPONSE,  "Timing test data response" },

    { CLIENT_COMMAND_TIMING_TEST_DATA_REQUEST,   "Timing test data request" },

    { CLIENT_COMMAND_AUTHENTICATION_CHALLENGE,   "Authentication challenge" },

    { CLIENT_COMMAND_NETWORK_TIMER_TEST,         "Network timer test" },

    { CLIENT_COMMAND_END_OF_MEDIA_STREAM,        "End of media stream" },

    { CLIENT_COMMAND_MEDIA_CHANGING_INDICATOR,   "Media changing indicator" },

    { CLIENT_COMMAND_STREAM_SELECTION_INDICATOR, "Stream selection indicator" },

    { 0,      NULL }

};

/* Command direction */

#define  TO_SERVER      0x0003

#define  TO_CLIENT      0x0004

static const value_string command_direction_vals[] =

{

    { TO_SERVER,  "To Server"},

    { TO_CLIENT,  "To Client"},

    { 0, NULL }

};

static const value_string tcp_flags_vals[] =

{

    { 0x00,     "Middle of packet series" },

    { 0x04,     "First packet of a packet series" },

    { 0x08,     "Last packet of a packet series" },

    { 0x0C,     "There is only one packet in this series"  },

    { 0x10,     "UDP packet pair timing packet" },

    { 0,        NULL }

};

static const value_string media_result_flags_vals[] =

{

    { 0x01,  "Media file name was accepted (no auth)"},

    { 0x02,  "Authentication for this media was accepted (BASIC auth)"},

    { 0x03,  "Authentication accepted (NTLM auth)"},

    { 0, NULL }

};

static const value_string broadcast_indexing_vals[] =

{

    { 0x00,  "No indexed seeking (live or no video streams)"},

    { 0x80,  "Indexed seeking (video streams available)"},

    { 0, NULL }

};

static const value_string broadcast_liveness_vals[] =

{

    { 0x01,  "Pre-recorded broadcast"},

    { 0x02,  "Live broadcast"},

    { 0x42,  "Presentation which includes a script command"},

    { 0, NULL }

};

static const value_string stream_selection_action_vals[] =

{

    { 0x00,  "Stream at full frame rate"},

    { 0x01,  "Only stream key frames"},

    { 0x02,  "No stream, switch it off"},

    { 0, NULL }

};

/* Server to client error codes */

static const value_string server_to_client_error_vals[] =

{

    { 0x00000000,  "OK"},

    { 0xC00D001A,  "File was not found"},

    { 0xC00D000E,  "The network is busy"},

    { 0xC00D000F,  "Too many connection sessions to server exist, cannot connect"},

    { 0xC00D0029,  "The network has failed - connection was lost"},

    { 0xC00D0034,  "There is no more data in the stream (UDP)"},

    { 0x80070005,  "You do not have access to the location or file"},

    { 0xC00D0013,  "There was no timely response from the server"},

    { 0x80070057,  "A parameter in the location is incorrect"},

    { 0x8000FFFF,  "File failed to open"},

    { 0, NULL }

};

/*************************/

/* Function declarations */

void proto_register_msmms(void);

void proto_reg_handoff_msmms_command(void);

static int dissect_msmms_command(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);

static int dissect_msmms_data(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);

static int dissect_msmms_data_udp_command(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);

static void dissect_client_transport_info(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,

                                          unsigned offset, unsigned length_remaining);

static void dissect_server_info(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,

                                unsigned offset);

static void dissect_client_player_info(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,

                                       unsigned offset, unsigned length_remaining);

static void dissect_start_sending_from_info(tvbuff_t *tvb, proto_tree *tree, unsigned offset);

static void dissect_cancel_info(tvbuff_t *tvb, proto_tree *tree, unsigned offset);

static void dissect_timing_test_request(tvbuff_t *tvb, proto_tree *tree, unsigned offset);

static void dissect_timing_test_response(tvbuff_t *tvb, proto_tree *tree, unsigned offset);

static void dissect_request_server_file(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,

                                        unsigned offset, unsigned length_remaining);

static void dissect_media_details(tvbuff_t *tvb, proto_tree *tree, unsigned offset);

static void dissect_header_response(tvbuff_t *tvb, proto_tree *tree, unsigned offset);

static void dissect_network_timer_test_response(tvbuff_t *tvb, proto_tree *tree, unsigned offset);

static void dissect_transport_info_response(tvbuff_t *tvb, proto_tree *tree, unsigned offset,

                                            unsigned length_remaining);

static void dissect_media_stream_mbr_selector(tvbuff_t *tvb, proto_tree *tree, unsigned offset);

static void dissect_header_request(tvbuff_t *tvb, proto_tree *tree, unsigned offset);

static void dissect_stop_button_pressed(tvbuff_t *tvb, proto_tree *tree, unsigned offset);

static void msmms_data_add_address(packet_info *pinfo, address *addr, conversation_type ckt, int port);

/****************************/

/* Main dissection function */

/****************************/

static int dissect_msmms_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)

{

    /* Work out what type of packet this is and dissect it as such */

    /* Just don't dissect if can't even read command signature */

    if (tvb_captured_length(tvb) < 8) {

        return 0;

    }

    /* Command */

    if (tvb_get_letohl(tvb, 4) == 0xb00bface)

    {

        return dissect_msmms_command(tvb, pinfo, tree);

    }

    else

    /* UDP data command */

    if ((pinfo->ptype == PT_UDP) && (pinfo->destport == MSMMS_PORT))

    {

        return dissect_msmms_data_udp_command(tvb, pinfo, tree);

    }

    else

    /* Assume data (don't consider frames from client->server data...) */

    if (pinfo->destport != MSMMS_PORT)

    {

        return dissect_msmms_data(tvb, pinfo, tree);

    }

    /* It was none of the above so assume not really an MMS packet */

    return 0;

}

/*************************************/

/* Dissection of different PDU types */

/*************************************/

/* Dissect command packet */

static int dissect_msmms_command(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)

{

    int         offset                    = 0;

    proto_item *ti;

    proto_tree *msmms_tree;

    proto_tree *msmms_common_command_tree;

    uint32_t    sequence_number;

    uint16_t    command_id;

    uint16_t    command_dir;

    uint32_t    length_of_command;

    uint32_t    length_remaining;

    /******************************/

    /* Check for available length */

    /* Need to have enough bytes for length field */

    if (tvb_reported_length_remaining(tvb, offset) < 12)

    {

        pinfo->desegment_offset = 0;  /* Start at beginning next time */

        pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;     /* Need one more byte to try again */

        return -1;

    }

    /* Read length field and see if we're short */

    length_of_command = tvb_get_letohl(tvb, offset+8);

    if (tvb_reported_length_remaining(tvb, 16) < length_of_command)

    {

        pinfo->desegment_offset = 0; /* Start at beginning next time */

        pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;   /* Need one more byte to try again */

        return -1;

    }

    /* Set columns */

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

    col_set_str(pinfo->cinfo, COL_INFO, "Command: ");

    /* Add hidden filter for "msmms.command" */

    ti = proto_tree_add_item(tree, hf_msmms_command, tvb, 0, 0, ENC_ASCII);

    proto_item_set_hidden(ti);

    /* Create MSMMS control protocol tree */

    ti = proto_tree_add_item(tree, proto_msmms, tvb, offset, -1, ENC_NA);

    msmms_tree = proto_item_add_subtree(ti, ett_msmms_command);

    /* Read command ID and direction now so can give common command header a

       descriptive label */

    command_id = tvb_get_letohs(tvb, 36);

    command_dir = tvb_get_letohs(tvb, 36+2);

    /*************************/

    /* Common command header */

    /* Add a tree for common header */

    ti =  proto_tree_add_string_format(msmms_tree, hf_msmms_command_common_header, tvb, offset, -1,

            "",

            "%s (to %s)",

            (command_dir == TO_SERVER) ?

            val_to_str_const(command_id, to_server_command_vals, "Unknown") :

            val_to_str_const(command_id, to_client_command_vals, "Unknown"),

            (command_dir == TO_SERVER) ? "server" : "client");

    msmms_common_command_tree = proto_item_add_subtree(ti, ett_msmms_command_common_header);

    /* Format of 1st 4 bytes unknown.  May be version... */

    offset += 4;

    /* Signature (already verified by main dissection function) */

    proto_tree_add_item(msmms_common_command_tree, hf_msmms_command_signature, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* Length of command */

    proto_tree_add_item(msmms_common_command_tree, hf_msmms_command_length, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* Protocol name.  Must be "MMS"... */

    if (strncmp((char*)tvb_get_string_enc(pinfo->pool, tvb, offset, 3, ENC_ASCII), "MMS", 3) != 0)

    {

        return offset;

    }

    proto_tree_add_item(msmms_common_command_tree, hf_msmms_command_protocol_type, tvb, offset, 4, ENC_ASCII);

    offset += 4;

    /* Remaining length in multiples of 8 bytes */

    proto_tree_add_item(msmms_common_command_tree, hf_msmms_command_length_remaining, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* Sequence number */

    proto_tree_add_item_ret_uint(msmms_common_command_tree, hf_msmms_command_sequence_number, tvb, offset, 4, ENC_LITTLE_ENDIAN, &sequence_number);

    offset += 4;

    /* Timestamp */

    proto_tree_add_item(msmms_common_command_tree, hf_msmms_command_timestamp, tvb, offset, 8, ENC_LITTLE_ENDIAN);

    offset += 8;

    /* Another length remaining field... */

    length_remaining = tvb_get_letohl(tvb, offset);

    proto_tree_add_item(msmms_common_command_tree, hf_msmms_command_length_remaining2, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* Command depends up on direction */

    proto_tree_add_item(msmms_common_command_tree,

                        (command_dir == TO_SERVER) ?

                            hf_msmms_command_to_server_id :

                            hf_msmms_command_to_client_id,

                        tvb, offset, 2, ENC_LITTLE_ENDIAN);

    offset += 2;

    /* Direction */

    proto_tree_add_item(msmms_common_command_tree, hf_msmms_command_direction, tvb, offset, 2, ENC_LITTLE_ENDIAN);

    offset += 2;

    /* This is the end of the common command header */

    proto_item_set_len(msmms_common_command_tree, offset);

    /* Show summary in info column */

    col_append_fstr(pinfo->cinfo, COL_INFO,

                    "seq=%03u: %s %s",

                    sequence_number,

                    (command_dir == TO_SERVER) ? "-->" : "<--",

                    (command_dir == TO_SERVER) ?

                        val_to_str_const(command_id, to_server_command_vals, "Unknown") :

                        val_to_str_const(command_id, to_client_command_vals, "Unknown"));

    /* Adjust length_remaining for command-specific details */

    length_remaining = (length_remaining*8) - 8;

    /* Now parse any command-specific params */

    if (command_dir == TO_SERVER)

    {

        /* Commands to server */

        switch (command_id)

        {

            case SERVER_COMMAND_TRANSPORT_INFO:

                dissect_client_transport_info(tvb, pinfo, msmms_tree,

                                              offset, length_remaining);

                break;

            case SERVER_COMMAND_CONNECT_INFO:

                dissect_client_player_info(tvb, pinfo, msmms_tree,

                                           offset, length_remaining);

                break;

            case SERVER_COMMAND_START_SENDING_FROM:

                dissect_start_sending_from_info(tvb, msmms_tree, offset);

                break;

            case SERVER_COMMAND_CANCEL_PROTOCOL:

                dissect_cancel_info(tvb, msmms_tree, offset);

                break;

            case SERVER_COMMAND_TIMING_TEST_DATA_REQUEST:

                dissect_timing_test_request(tvb, tree, offset);

                break;

            case SERVER_COMMAND_REQUEST_SERVER_FILE:

                dissect_request_server_file(tvb, pinfo, tree, offset, length_remaining);

                break;

            case SERVER_COMMAND_NETWORK_TIMER_TEST_RESPONSE:

                dissect_network_timer_test_response(tvb, tree, offset);

                break;

            case SERVER_COMMAND_MEDIA_STREAM_MBR_SELECTOR:

                dissect_media_stream_mbr_selector(tvb, tree, offset);

                break;

            case SERVER_COMMAND_HEADER_REQUEST:

                dissect_header_request(tvb, tree, offset);

                break;

            case SERVER_COMMAND_STOP_BUTTON_PRESSED:

                dissect_stop_button_pressed(tvb, tree, offset);

                break;

            /* TODO: other commands */

            default:

                break;

        }

    }

    else

    {

        /* Commands to client */

        switch (command_id)

        {

            case CLIENT_COMMAND_SERVER_INFO:

                dissect_server_info(tvb, pinfo, msmms_tree, offset);

                break;

            case CLIENT_COMMAND_TIMING_TEST_DATA_RESPONSE:

                dissect_timing_test_response(tvb, tree, offset);

                break;

            case CLIENT_COMMAND_MEDIA_DETAILS:

                dissect_media_details(tvb, tree, offset);

                break;

            case CLIENT_COMMAND_SENDING_HEADER_RESPONSE:

                dissect_header_response(tvb, tree, offset);

                break;

            case CLIENT_COMMAND_TRANSPORT_INFO_ACK:

                dissect_transport_info_response(tvb, tree, offset, length_remaining);

                break;

            /* TODO: other commands: */

            default:

                break;

        }

    }

    /* Got to the end so assume it belongs to this protocol */

    return length_of_command + 12;

}

/* Parse the only known UDP command (0x01) */

static int dissect_msmms_data_udp_command(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)

{

    proto_item *ti;

    proto_tree *msmms_tree;

    int         offset     = 0;

    /* Set protocol column */

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

    /* Create MSMMS data protocol tree */

    ti = proto_tree_add_item(tree, proto_msmms, tvb, offset, -1, ENC_NA);

    msmms_tree = proto_item_add_subtree(ti, ett_msmms_data);

    /* Header ID */

    proto_tree_add_item(msmms_tree, hf_msmms_data_header_id, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* Client ID */

    proto_tree_add_item(msmms_tree, hf_msmms_data_client_id, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* Command ID */

    proto_tree_add_item(msmms_tree, hf_msmms_data_command_id, tvb, offset, 2, ENC_LITTLE_ENDIAN);

    offset += 4;

    col_set_str(pinfo->cinfo, COL_INFO, "Request to resend packet(s):");

    /* Show list of packets to resend */

    while (tvb_reported_length_remaining(tvb, offset) >= 4)

    {

        uint32_t packet_number = tvb_get_letohl(tvb, offset);

        proto_tree_add_item(msmms_tree, hf_msmms_data_packet_to_resend, tvb, offset, 4, ENC_LITTLE_ENDIAN);

        offset += 4;

        col_append_fstr(pinfo->cinfo, COL_INFO, " %u", packet_number);

    }

    /* Report that whole of UDP packet was dissected */

    return tvb_reported_length_remaining(tvb, 0);

}

/* Dissect a data packet */

static int dissect_msmms_data(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)

{

    int         offset = 0;

    proto_item  *ti;

    proto_tree  *msmms_tree;

    proto_tree  *msmms_data_timing_pair_tree = NULL;

    uint32_t    sequence_number;

    uint16_t    packet_length;

    uint16_t    packet_length_found;

    uint8_t     value = 0;

    /* How many bytes do we need? */

    packet_length = tvb_get_letohs(tvb, 6);

    /* How many bytes have we got? */

    packet_length_found = tvb_reported_length_remaining(tvb, 0);

    /* Reject frame reported not to reach length field */

    if (packet_length < 8)

    {

        return 0;

    }

    /* Stop and ask for more bytes if necessary */

    if (packet_length_found < packet_length)

    {

        pinfo->desegment_offset = 0;  /* Start from beginning again next time */

        pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;     /* Try again with even one more byte */

        return -1;

    }

    /* Will reject packet if is TCP and has invalid flag */

    if (pinfo->ptype == PT_TCP)

    {

        /* Flag value is in 5th byte */

        value = tvb_get_uint8(tvb, 5);

        /* Reject packet if not a recognised packet type */

        if (try_val_to_str(value, tcp_flags_vals) == NULL)

        {

            return 0;

        }

    }

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

    /* Add hidden filter for "msmms.data" */

    ti = proto_tree_add_item(tree, hf_msmms_data, tvb, 0, 0, ENC_NA);

    proto_item_set_hidden(ti);

    /* Create MSMMS data protocol tree */

    ti = proto_tree_add_item(tree, proto_msmms, tvb, offset, -1, ENC_NA);

    msmms_tree = proto_item_add_subtree(ti, ett_msmms_data);

    /* Sequence number */

    proto_tree_add_item_ret_uint(msmms_tree, hf_msmms_data_sequence_number, tvb, offset, 4, ENC_LITTLE_ENDIAN, &sequence_number);

    offset += 4;

    /* Packet ID type */

    proto_tree_add_item(msmms_tree, hf_msmms_data_packet_id_type, tvb, offset, 1, ENC_LITTLE_ENDIAN);

    offset++;

    /* Next byte depends upon whether UDP or TCP */

    if (pinfo->ptype == PT_UDP)

    {

        /* UDP */

        proto_tree_add_item(msmms_tree, hf_msmms_data_udp_sequence, tvb,

                            offset, 1, ENC_LITTLE_ENDIAN);

    }

    else

    {

        /* TCP */

        proto_tree_add_item(msmms_tree, hf_msmms_data_tcp_flags, tvb,

                            offset, 1, ENC_LITTLE_ENDIAN);

    }

    offset++;

    /* Packet Length */

    proto_tree_add_item_ret_uint16(msmms_tree, hf_msmms_data_packet_length, tvb, offset, 2, ENC_LITTLE_ENDIAN, &packet_length);

    offset += 2;

    /* Parse UDP Timing packet pair headers if present */

    if (value == 0x01)

    {

        /* Create subtree */

        ti =  proto_tree_add_string_format(msmms_tree, hf_msmms_data_timing_pair, tvb, offset, 8, "", "Data timing pair");

        msmms_data_timing_pair_tree = proto_item_add_subtree(ti, ett_msmms_data_timing_packet_pair);

        proto_tree_add_item(msmms_data_timing_pair_tree, hf_msmms_data_timing_pair_seqno, tvb, offset, 1, ENC_LITTLE_ENDIAN);

        offset++;

        proto_tree_add_item(msmms_data_timing_pair_tree, hf_msmms_data_timing_pair_flags, tvb, offset, 3, ENC_LITTLE_ENDIAN);

        offset += 3;

        proto_tree_add_item(msmms_data_timing_pair_tree, hf_msmms_data_timing_pair_id, tvb, offset, 1, ENC_LITTLE_ENDIAN);

        offset++;

        proto_tree_add_item(msmms_data_timing_pair_tree, hf_msmms_data_timing_pair_flag, tvb, offset, 1, ENC_LITTLE_ENDIAN);

        offset++;

        proto_tree_add_item(msmms_data_timing_pair_tree, hf_msmms_data_timing_pair_packet_length, tvb, offset, 2, ENC_LITTLE_ENDIAN);

        offset += 2;

    }

    /* Everything else is marked as unparsed data */

    proto_tree_add_item(msmms_tree, hf_msmms_data_unparsed, tvb, offset, packet_length-offset, ENC_NA);

    offset = packet_length;

    /* Show summary in info column */

    col_add_fstr(pinfo->cinfo, COL_INFO, "Data: seq=%05u, len=%05u",

                 sequence_number, packet_length);

    /* Whole of packet length has been dissected now */

    return offset;

}

/***************************************/

/* Dissect command-specific parameters */

/***************************************/

/* Transport information (address, port, etc) */

static void dissect_client_transport_info(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,

                                          unsigned offset, unsigned length_remaining)

{

    char    *transport_info;

    unsigned   ipaddr[4];

    char    protocol[3+1] = "";

    unsigned   port;

    int     fields_matched;

    /* Flags */

    proto_tree_add_item(tree, hf_msmms_command_prefix1, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    proto_tree_add_item(tree, hf_msmms_command_prefix2, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* These 12 bytes are not understood */

    offset += 4;

    offset += 4;

    offset += 4;

    /* Extract and show the string in tree and info column */

    transport_info = (char*)tvb_get_string_enc(pinfo->pool, tvb, offset, length_remaining - 20, ENC_UTF_16|ENC_LITTLE_ENDIAN);

    proto_tree_add_string(tree, hf_msmms_command_client_transport_info, tvb,

                                 offset, length_remaining-20, transport_info);

    col_append_fstr(pinfo->cinfo, COL_INFO, " (%s)",

                    format_text_string(pinfo->pool, transport_info));

    /* Try to extract details from this string */

    fields_matched = sscanf(transport_info, "%*c%*c%u.%u.%u.%u%*c%3s%*c%u",

                            &ipaddr[0], &ipaddr[1], &ipaddr[2], &ipaddr[3],

                            protocol, &port);

    /* Use this information to set up a conversation for the data stream */

    if (fields_matched == 6)

    {

        conversation_type ckt = CONVERSATION_NONE;

        /* Work out the port type */

        if (strncmp(protocol, "UDP", 3) == 0)

        {

            ckt = CONVERSATION_UDP;

        }

        else

        if (strncmp(protocol, "TCP", 3) == 0)

        {

            ckt = CONVERSATION_TCP;

        }

        /* Set the dissector for indicated conversation */

        if (ckt != CONVERSATION_NONE)

        {

            uint8_t octets[4];

            address addr;

            octets[0] = ipaddr[0];

            octets[1] = ipaddr[1];

            octets[2] = ipaddr[2];

            octets[3] = ipaddr[3];

            addr.type = AT_IPv4;

            addr.len = 4;

            addr.data = octets;

            msmms_data_add_address(pinfo, &addr, ckt, port);

        }

    }

}

/* Dissect server data */

static void dissect_server_info(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,

                                unsigned offset)

{

    uint32_t      server_version_length;

    uint32_t      tool_version_length;

    uint32_t      download_update_player_length;

    uint32_t      password_encryption_type_length;

    const char   *server_version;

    /* ErrorCode */

    proto_tree_add_item(tree, hf_msmms_command_prefix1_error, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    proto_tree_add_item(tree, hf_msmms_command_prefix2, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* Next 8 words are not understood */

    offset += 4;

    offset += 4;

    offset += 4;

    offset += 4;

    offset += 4;

    offset += 4;

    offset += 4;

    offset += 4;

    /* Length of server version */

    proto_tree_add_item_ret_uint(tree, hf_msmms_command_server_version_length, tvb, offset, 4, ENC_LITTLE_ENDIAN, &server_version_length);

    offset += 4;

    /* Length of tool version */

    proto_tree_add_item_ret_uint(tree, hf_msmms_command_tool_version_length, tvb, offset, 4, ENC_LITTLE_ENDIAN, &tool_version_length);

    offset += 4;

    /* Length of download update player URL */

    download_update_player_length = tvb_get_letohl(tvb, offset);

    proto_tree_add_item(tree, hf_msmms_command_update_url_length, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* Length of password encryption type */

    password_encryption_type_length = tvb_get_letohl(tvb, offset);

    proto_tree_add_item(tree, hf_msmms_command_password_type_length, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* Server version string. */

    if (server_version_length > 1)

    {

        /* Server version string */

        proto_tree_add_item_ret_string(tree, hf_msmms_command_server_version, tvb,

                            offset, server_version_length*2,

                            ENC_UTF_16|ENC_LITTLE_ENDIAN, pinfo->pool, (const uint8_t**)&server_version);

        col_append_fstr(pinfo->cinfo, COL_INFO, " (version='%s')",

                    format_text_string(pinfo->pool, server_version));

    }

    offset += (server_version_length*2);

    /* Tool version string. */

    if (tool_version_length > 1)

    {

        proto_tree_add_item(tree, hf_msmms_command_tool_version, tvb,

                            offset, tool_version_length*2,

                            ENC_UTF_16|ENC_LITTLE_ENDIAN);

    }

    offset += (tool_version_length*2);

    /* Download update player url string. */

    if (download_update_player_length > 1)

    {

        proto_tree_add_item(tree, hf_msmms_command_update_url, tvb,

                            offset, download_update_player_length*2,

                            ENC_UTF_16|ENC_LITTLE_ENDIAN);

    }

    offset += (download_update_player_length*2);

    /* Password encryption type string. */

    if (password_encryption_type_length > 1)

    {

        proto_tree_add_item(tree, hf_msmms_command_password_type, tvb,

                            offset, password_encryption_type_length*2,

                            ENC_UTF_16|ENC_LITTLE_ENDIAN);

    }

/*    offset += (password_encryption_type_length*2); */

}

/* Player (client) information */

static void dissect_client_player_info(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,

                                       unsigned offset, unsigned length_remaining)

{

    const char *player_info;

    /* Flags */

    proto_tree_add_item(tree, hf_msmms_command_prefix1, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    proto_tree_add_item(tree, hf_msmms_command_prefix2, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* These 4 bytes are not understood */

    offset += 4;

    /* Extract and show the string in tree and info column */

    proto_tree_add_item_ret_string(tree, hf_msmms_command_client_player_info, tvb,

                        offset, length_remaining-12,

                        ENC_UTF_16|ENC_LITTLE_ENDIAN, pinfo->pool, (const uint8_t**)&player_info);

    col_append_fstr(pinfo->cinfo, COL_INFO, " (%s)",

                    format_text_string(pinfo->pool, player_info));

}

/* Dissect info about where client wants to start playing from */

static void dissect_start_sending_from_info(tvbuff_t *tvb, proto_tree *tree, unsigned offset)

{

    /* Command Level */

    proto_tree_add_item(tree, hf_msmms_command_prefix1_command_level, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    proto_tree_add_item(tree, hf_msmms_command_prefix2, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    /* 40 bytes follow the prefixes... */

}

/* Dissect cancel parameters */

static void dissect_cancel_info(tvbuff_t *tvb, proto_tree *tree, unsigned offset)

{

    /* Command Level */

    proto_tree_add_item(tree, hf_msmms_command_prefix1_command_level, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    proto_tree_add_item(tree, hf_msmms_command_prefix2, tvb, offset, 4, ENC_LITTLE_ENDIAN);

}

/* Dissect timing test data request */

static void dissect_timing_test_request(tvbuff_t *tvb, proto_tree *tree, unsigned offset)

{

    /* Flags */

    proto_tree_add_item(tree, hf_msmms_command_prefix1, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    proto_tree_add_item(tree, hf_msmms_command_prefix2, tvb, offset, 4, ENC_LITTLE_ENDIAN);

}

/* Dissect timing test data response */

static void dissect_timing_test_response(tvbuff_t *tvb, proto_tree *tree, unsigned offset)

{

    /* ErrorCode */

    proto_tree_add_item(tree, hf_msmms_command_prefix1_error, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* Flags */

    proto_tree_add_item(tree, hf_msmms_command_prefix2, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    /* Number of 4 byte fields in structure */

    proto_tree_add_item(tree, hf_msmms_command_number_of_words, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    offset += 4;

    offset += 4;

    /* Client ID */

    proto_tree_add_item(tree, hf_msmms_command_client_id, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    /* 20 more bytes... */

}

/* Dissect request for server file */

static void dissect_request_server_file(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,

                                        unsigned offset, unsigned length_remaining)

{

    const char *server_file;

    /* Command Level */

    proto_tree_add_item(tree, hf_msmms_command_prefix1_command_level, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    proto_tree_add_item(tree, hf_msmms_command_prefix2, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    offset += 4;

    offset += 4;

    /* File path on server */

    proto_tree_add_item_ret_string(tree, hf_msmms_command_server_file, tvb,

                        offset, length_remaining-16,

                        ENC_UTF_16|ENC_LITTLE_ENDIAN, pinfo->pool, (const uint8_t**)&server_file);

    col_append_fstr(pinfo->cinfo, COL_INFO, " (%s)",

                    format_text_string(pinfo->pool, server_file));

}

/* Dissect media details from server */

static void dissect_media_details(tvbuff_t *tvb, proto_tree *tree, unsigned offset)

{

    /* ErrorCode */

    proto_tree_add_item(tree, hf_msmms_command_prefix1_error, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    proto_tree_add_item(tree, hf_msmms_command_prefix2, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;