/src/wireshark/epan/dissectors/packet-mausb.c

Source
/* packet-mausb.c
 * Routines for Media Agnostic USB dissection
 * Copyright 2014, Intel Corporation
 * Author: Sean O. Stalley <sean.stalley@intel.com>
 *
 * Dedicated to Robert & Dorothy Stalley
 *
 * 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/expert.h>
#include <epan/oui.h>
#include "packet-tcp.h"
#include "packet-llc.h"
#include "packet-usb.h"
#include "packet-mausb.h"

void proto_reg_handoff_mausb(void);
void proto_register_mausb(void);

static dissector_handle_t mausb_tcp_handle;
static dissector_handle_t mausb_pkt_handle;

/* For SNAP Packets */
static int hf_llc_mausb_pid;

/* Initialize the protocol and registered fields */
static int proto_mausb;
static int hf_mausb_version;
static int hf_mausb_flags;
static int hf_mausb_flag_host;
static int hf_mausb_flag_retry;
static int hf_mausb_flag_timestamp;
static int hf_mausb_flag_reserved;


static int * const mausb_flag_fields[] = {
    &hf_mausb_flag_host,
    &hf_mausb_flag_retry,
    &hf_mausb_flag_timestamp,
    &hf_mausb_flag_reserved,
    NULL
};

static int hf_mausb_type;
static int hf_mausb_length;
static int hf_mausb_dev_handle;
static int hf_mausb_ep_handle;
static int hf_mausb_ep_handle_d;
static int hf_mausb_ep_handle_ep_num;
static int hf_mausb_ep_handle_dev_addr;
static int hf_mausb_ep_handle_bus_num;
static int hf_mausb_ma_dev_addr;
static int hf_mausb_ssid;
static int hf_mausb_status;

/* management packet specific */
static int hf_mausb_token;
static int hf_mausb_mgmt_pad;
static int hf_mausb_mgmt_ep_handle_num;
static int hf_mausb_mgmt_ep_handle_pad;
static int hf_mausb_mgmt_ep_des_num;
static int hf_mausb_mgmt_ep_des_size;
static int hf_mausb_mgmt_ep_des_pad;
static int hf_mausb_mgmt_type_spec;
static int hf_mausb_mgmt_type_spec_generic;

/* CapResp packet specific */
static int hf_mausb_cap_resp_num_ep;
static int hf_mausb_cap_resp_num_dev;
static int hf_mausb_cap_resp_num_stream;
static int hf_mausb_cap_resp_dev_type;
static int hf_mausb_cap_resp_desc_count;
static int hf_mausb_cap_resp_desc_len;
static int hf_mausb_cap_resp_transfer_req;
static int hf_mausb_cap_resp_mgmt_req;
static int hf_mausb_cap_resp_rsvd;

static int hf_mausb_dev_cap_len;
static int hf_mausb_dev_cap_type;
static int hf_mausb_dev_cap_generic;

/* EPHandleReq & Resp packet specific */
static int hf_mausb_ep_handle_req_pad;
static int hf_mausb_ep_handle_resp_dir;
static int hf_mausb_ep_handle_resp_iso;
static int hf_mausb_ep_handle_resp_lman;
static int hf_mausb_ep_handle_resp_valid;
static int hf_mausb_ep_handle_resp_ccu;
static int hf_mausb_ep_handle_resp_buf_size;
static int hf_mausb_ep_handle_resp_iso_prog_dly;
static int hf_mausb_ep_handle_resp_iso_resp_dly;

/* (Clear/Cancel)TransferReq & Resp packet specific */
static int hf_mausb_clear_transfers_info_block;
static int hf_mausb_clear_transfers_status_block;
static int hf_mausb_cancel_transfer_rsvd;
static int hf_mausb_clear_transfers_req_num;
static int hf_mausb_clear_transfers_req_rsvd;
static int hf_mausb_clear_transfers_resp_num;
static int hf_mausb_clear_transfers_resp_rsvd;
static int hf_mausb_cancel_transfer_status;
static int hf_mausb_cancel_transfer_rsvd_2;
static int hf_mausb_clear_transfers_status;
static int hf_mausb_clear_transfers_partial;
static int hf_mausb_clear_transfers_start_req_id;
static int hf_mausb_clear_transfers_last_req_id;
static int hf_mausb_clear_transfers_req_block_rsvd;
static int hf_mausb_clear_transfers_resp_block_rsvd;
static int hf_mausb_cancel_transfer_seq_num;
static int hf_mausb_cancel_transfer_byte_offset;

/* data packet specific */
static int hf_mausb_eps;
static int hf_mausb_eps_rsvd;
static int hf_mausb_tflags;
static int hf_mausb_tflag_arq;
static int hf_mausb_tflag_neg;
static int hf_mausb_tflag_eot;
static int hf_mausb_tflag_type;
static int hf_mausb_tflag_rsvd;

static int * const mausb_tflag_fields[] = {
    &hf_mausb_tflag_arq,
    &hf_mausb_tflag_neg,
    &hf_mausb_tflag_eot,
    &hf_mausb_tflag_type,
    &hf_mausb_tflag_rsvd,
    NULL
};

static int hf_mausb_num_iso_hdr;
static int hf_mausb_iflags;
static int hf_mausb_iflag_mtd;
static int hf_mausb_iflag_hdr_format;
static int hf_mausb_iflag_asap;

static int * const mausb_iflag_fields[] = {
    &hf_mausb_iflag_mtd,
    &hf_mausb_iflag_hdr_format,
    &hf_mausb_iflag_asap,
    NULL
};

static int hf_mausb_stream_id;
static int hf_mausb_seq_num;
static int hf_mausb_req_id;
static int hf_mausb_present_time;
static int hf_mausb_uframe;
static int hf_mausb_frame;
static int hf_mausb_num_segs;

static int hf_mausb_timestamp;
static int hf_mausb_delta;
static int hf_mausb_nom_interval;



static int hf_mausb_mtd;
static int hf_mausb_rem_size_credit;

/* expert info fields */
static expert_field ei_ep_handle_len;
static expert_field ei_len;
static expert_field ei_mgmt_type_undef;
static expert_field ei_mgmt_type_spec_len_long;
static expert_field ei_mgmt_type_spec_len_short;
static expert_field ei_dev_cap_len;
static expert_field ei_dev_cap_resp_desc_len;
static expert_field ei_cap_resp_desc_len;

/* MAUSB Version, per 6.2.1.1 */
#define MAUSB_VERSION_1_0     0x0
#define MAUSB_VERSION_MASK    0x0F

/* for dissecting snap packets */
/*
 * TODO: determine assigned PID value
 * (yet to be assigned as of Earth Day 2014)
 */
#define PID_MAUSB 0x1500

static const value_string mausb_pid_string[] = {
    { PID_MAUSB, "MAUSB" },
    { 0, NULL}
};

static const value_string mausb_version_string[] = {
    { MAUSB_VERSION_1_0, "MAUSB protocol version 1.0" },
    { 0, NULL}
};

/* Packet flags, per 6.2.1.2 */
#define MAUSB_FLAG_MASK       0xF0
#define MAUSB_FLAG_HOST       (1 << 0)
#define MAUSB_FLAG_RETRY      (1 << 1)
#define MAUSB_FLAG_TIMESTAMP  (1 << 2)
#define MAUSB_FLAG_RESERVED   (1 << 3)
#define MAUSB_FLAG_OFFSET     4

/* Packet Types, per 6.2.1.3 */
#define MAUSB_PKT_TYPE_MASK       0xC0
#define MAUSB_PKT_TYPE_MGMT       (0 << 6)
#define MAUSB_PKT_TYPE_CTRL       (1 << 6)
#define MAUSB_PKT_TYPE_DATA       (2 << 6)

/* Packet Subtypes, per 6.2.1.3 */
#define MAUSB_SUBTYPE_MASK        0x3F

enum mausb_pkt_type {
    /* Management packets */
    CapReq = 0x00 | MAUSB_PKT_TYPE_MGMT,
    CapResp               ,
    USBDevHandleReq       ,
    USBDevHandleResp      ,
    EPHandleReq           ,
    EPHandleResp          ,
    EPActivateReq         ,
    EPActivateResp        ,
    EPInactivateReq       ,
    EPInactivateResp      ,
    EPResetReq            ,
    EPResetResp           ,
    ClearTransfersReq     ,
    ClearTransfersResp    ,
    EPHandleDeleteReq     ,
    EPHandleDeleteResp    ,

    DevResetReq           ,
    DevResetResp          ,
    ModifyEP0Req          ,
    ModifyEP0Resp         ,
    SetUSBDevAddrReq      ,
    SetUSBDevAddrResp     ,
    UpdateDevReq          ,
    UpdateDevResp         ,
    USBDevDisconnectReq   ,
    USBDevDisconnectResp  ,
    USBSuspendReq         ,
    USBSuspendResp        ,
    USBResumeReq          ,
    USBResumeResp         ,
    RemoteWakeReq         ,
    RemoteWakeResp        ,

    PingReq               ,
    PingResp              ,
    DevDisconnectReq      ,
    DevDisconnectResp     ,
    DevInitDisconnectReq  ,
    DevInitDisconnectResp ,
    SynchReq              ,
    SynchResp             ,
    CancelTransferReq     ,
    CancelTransferResp    ,
    EPOpenStreamReq       ,
    EPOpenStreamResp      ,
    EPCloseStreamReq      ,
    EPCloseStreamResp     ,
    USBDevResetReq        ,
    USBDevResetResp       ,

    DevNotificationReq    ,
    DevNotificationResp   ,
    EPSetKeepAliveReq     ,
    EPSetKeepAliveResp    ,
    GetPortBWReq          ,
    GetPortBWResp         ,
    SleepReq              ,
    SleepResp             ,
    WakeReq               ,
    WakeResp              ,

    /* Vendor-Specific Management Packets */
    VendorSpecificReq = 0x3E | MAUSB_PKT_TYPE_MGMT,
    VendorSpecificResp    ,

    /* Control Packets */
    TransferSetupReq = MAUSB_PKT_TYPE_CTRL,
    TransferSetupResp     ,
    TransferTearDownConf  ,

    /* Data Packets */
    TransferReq = MAUSB_PKT_TYPE_DATA,
    TransferResp          ,
    TransferAck           ,
    IsochTransferReq      ,
    IsochTransferResp
};


/**
 * Type & Subtype values for MAUSB packet variants, per 6.2.1.3, Table 5
 */
static const value_string mausb_type_string[] = {
    /* Management packets */
    { CapReq               , "CapReq" },
    { CapResp              , "CapResp" },
    { USBDevHandleReq      , "USBDevHandleReq" },
    { USBDevHandleResp     , "USBDevHandleResp" },
    { EPHandleReq          , "EPHandleReq" },
    { EPHandleResp         , "EPHandleResp" },
    { EPActivateReq        , "EPActivateReq" },
    { EPActivateResp       , "EPActivateResp" },
    { EPInactivateReq      , "EPInactivateReq" },
    { EPInactivateResp     , "EPInactivateResp" },
    { EPResetReq           , "EPResetReq" },
    { EPResetResp          , "EPResetResp" },
    { ClearTransfersReq    , "ClearTransfersReq" },
    { ClearTransfersResp   , "ClearTransfersResp" },
    { EPHandleDeleteReq    , "EPHandleDeleteReq" },
    { EPHandleDeleteResp   , "EPHandleDeleteResp" },

    { DevResetReq          , "DevResetReq" },
    { DevResetResp         , "DevResetResp" },
    { ModifyEP0Req         , "ModifyEP0Req" },
    { ModifyEP0Resp        , "ModifyEP0Resp" },
    { SetUSBDevAddrReq     , "SetUSBDevAddrReq" },
    { SetUSBDevAddrResp    , "SetUSBDevAddrResp" },
    { UpdateDevReq         , "UpdateDevReq" },
    { UpdateDevResp        , "UpdateDevResp" },
    { USBDevDisconnectReq  , "USBDevDisconnectReq" },
    { USBDevDisconnectResp , "USBDevDisconnectResp" },
    { USBSuspendReq        , "USBSuspendReq" },
    { USBSuspendResp       , "USBSuspendResp" },
    { USBResumeReq         , "USBResumeReq" },
    { USBResumeResp        , "USBResumeResp" },
    { RemoteWakeReq        , "RemoteWakeReq" },
    { RemoteWakeResp       , "RemoteWakeResp" },

    { PingReq              , "PingReq" },
    { PingResp             , "PingResp" },
    { DevDisconnectReq     , "DevDisconnectReq " },
    { DevDisconnectResp    , "DevDisconnectResp" },
    { DevInitDisconnectReq , "DevInitDisconnectReq" },
    { DevInitDisconnectResp, "DevInitDisconnectResp" },
    { SynchReq             , "SynchReq" },
    { SynchResp            , "SynchResp" },
    { CancelTransferReq    , "CancelTransferReq" },
    { CancelTransferResp   , "CancelTransferResp" },
    { EPOpenStreamReq      , "EPOpenStreamReq" },
    { EPOpenStreamResp     , "EPOpenStreamResp" },
    { EPCloseStreamReq     , "EPCloseStreamReq" },
    { EPCloseStreamResp    , "EPCloseStreamResp" },
    { USBDevResetReq       , "USBDevResetReq" },
    { USBDevResetResp      , "USBDevResetResp" },

    { DevNotificationReq   , "DevNotificationReq" },
    { DevNotificationResp  , "DevNotificationResp" },
    { EPSetKeepAliveReq    , "EPSetKeepAliveReq" },
    { EPSetKeepAliveResp   , "EPSetKeepAliveResp" },
    { GetPortBWReq         , "GetPortBWReq" },
    { GetPortBWResp        , "GetPortBWResp" },
    { SleepReq             , "SleepReq" },
    { SleepResp            , "SleepResp" },
    { WakeReq              , "WakeReq" },
    { WakeResp             , "WakeResp" },

    /* Vendor-Specific Management Packets */
    { VendorSpecificReq    , "VendorSpecificReq" },
    { VendorSpecificResp   , "VendorSpecificResp" },

    /* Control Packets */
    { TransferSetupReq     , "TransferSetupReq" },
    { TransferSetupResp    , "TransferSetupResp" },
    { TransferTearDownConf , "TransferTearDownConf" },

    /* Data Packets */
    { TransferReq          , "TransferReq" },
    { TransferResp         , "TransferResp" },
    { TransferAck          , "TransferAck" },
    { IsochTransferReq     , "IsochTransferReq" },
    { IsochTransferResp    , "IsochTransferResp" },
    { 0, NULL}
};

#define MAUSB_EP_HANDLE_D        0x0001
#define MAUSB_EP_HANDLE_EP_NUM   0x001e
#define MAUSB_EP_HANDLE_DEV_ADDR 0x0fe0
#define MAUSB_EP_HANDLE_BUS_NUM  0xf000

#define MAUSB_EP_HANDLE_D_OFFSET        0
#define MAUSB_EP_HANDLE_EP_NUM_OFFSET   1
#define MAUSB_EP_HANDLE_DEV_ADDR_OFFSET 5
#define MAUSB_EP_HANDLE_BUS_NUM_OFFSET  12

static const value_string mausb_status_string[] = {
    {   0, "SUCCESS (NO_ERROR)" },
    { 128, "UNSUCCESSFUL" },
    { 129, "INVALID_MA_USB_SESSION_STATE" },
    { 130, "INVALID_DEVICE_HANDLE" },
    { 131, "INVALID_EP_HANDLE" },
    { 132, "INVALID_EP_HANDLE_STATE" },
    { 133, "INVALID_REQUEST" },
    { 134, "MISSING_SEQUENCE_NUMBER" },
    { 135, "TRANSFER_PENDING" },
    { 136, "TRANSFER_EP_STALL" },
    { 137, "TRANSFER_SIZE_ERROR" },
    { 138, "TRANSFER_DATA_BUFFER_ERROR" },
    { 139, "TRANSFER_BABBLE_DETECTED" },
    { 140, "TRANSFER_TRANSACTION_ERROR" },
    { 141, "TRANSFER_SHORT_TRANSFER" },
    { 142, "TRANSFER_CANCELLED" },
    { 143, "INSUFFICIENT_RESOURCES" },
    { 144, "NOT_SUFFICIENT_BANDWIDTH" },
    { 145, "INTERNAL_ERROR" },
    { 146, "DATA_OVERRUN" },
    { 147, "DEVICE_NOT_ACCESSED" },
    { 148, "BUFFER_OVERRUN" },
    { 149, "BUSY" },
    { 150, "DROPPED_PACKET" },
    { 151, "ISOC_TIME_EXPIRED" },
    { 152, "ISOCH_TIME_INVALID" },
    { 153, "NO_USB_PING_RESPONSE" },
    { 154, "NOT_SUPPORTED" },
    { 155, "REQUEST_DENIED" },
    { 156, "MISSING_REQUEST_ID" },
    { 0, NULL}
};


/* Number of Isochronous Headers, per 6.5.1.7 */
#define MAUSB_NUM_ISO_HDR_MASK 0x0fff

/* I-Flags, per 6.5.1.8 */
#define MAUSB_IFLAG_ASAP       (1 << 0)
#define MAUSB_IFLAG_HDR_FORMAT (3 << 1)
#define MAUSB_IFLAG_MTD        (1 << 3)
#define MAUSB_IFLAG_OFFSET     12
#define MAUSB_IFLAG_MASK       (0xF << MAUSB_IFLAG_OFFSET)

/* Presentation Time, per 6.5.1.9 */
#define MAUSB_PRESENT_TIME_MASK 0x000fffff
#define MAUSB_UFRAME_MASK       0x00000007
#define MAUSB_FRAME_MASK        0x000ffff8

/* Number of Segments, per 6.5.1.10 */
#define MAUSB_NUM_SEGS_MASK     0xfff00000

/* MA USB Global Time fields, per 6.6.1 */
#define MAUSB_DELTA_MASK        0x00000fff
#define MAUSB_INTERVAL_MASK     0xfffff000



#define MAUSB_TOKEN_MASK  0x03ff
#define MAUSB_MGMT_PAD_MASK  0xfffc
#define MAUSB_MGMT_NUM_EP_DES_MASK 0x1f
#define MAUSB_MGMT_SIZE_EP_DES_OFFSET 5
#define MAUSB_MGMT_SIZE_EP_DES_MASK (0x003f << MAUSB_MGMT_SIZE_EP_DES_OFFSET)

#define MAUSB_MGMT_CLEAR_TRANSFER_RESP_NUM_MASK 0x1f

/* CapResp Bitfield Masks */
#define MAUSB_CAP_RESP_NUM_STREAM_MASK 0x1f
#define MAUSB_CAP_RESP_DEV_TYPE_OFFSET 5
#define MAUSB_CAP_RESP_DEV_TYPE_MASK (0x07 << MAUSB_CAP_RESP_DEV_TYPE_OFFSET)
#define MAUSB_CAP_RESP_MGMT_REQ_MASK 0x0fff
#define MAUSB_CAP_RESP_RSVD_MASK 0xf000

static const value_string mausb_cap_resp_dev_type[] = {
    { 0, "Integrated Device" },
    { 1, "MAUSB 2.0 hub" },
    { 2, "MAUSB 3.1 hub" },
    { 0, NULL}
};

static const value_string mausb_dev_cap_string[] = {
    { 0, "Speed Capability" },
    { 1, "P-managed OUT Capabilities" },
    { 2, "Isochronous Capabilities" },
    { 3, "Synchronization Capabilities" },
    { 4, "Container ID Capability" },
    { 5, "Link Sleep Capability" },
    { 0, NULL}
};

enum mausb_dev_cap_type {
    SpeedCap = 0,
    PmanCap,
    IsoCap,
    SyncCap,
    ContainerIDCap,
    LinkSleepCap
};

#define DWORD_MASK 0xffffffff
#define MAUSB_MGMT_NUM_EP_HANDLE_PAD_MASK \
            (DWORD_MASK & !(MAUSB_MGMT_NUM_EP_DES_MASK))
#define MAUSB_MGMT_EP_DES_PAD_MASK \
            ((DWORD_MASK & !(MAUSB_MGMT_NUM_EP_DES_MASK | \
                           MAUSB_MGMT_SIZE_EP_DES_MASK)) >> 8)


/* EPHandleResp Bitfield Masks */
#define MAUSB_EP_HANDLE_RESP_DIR_MASK   (1 << 0)
#define MAUSB_EP_HANDLE_RESP_ISO_MASK   (1 << 1)
#define MAUSB_EP_HANDLE_RESP_LMAN_MASK  (1 << 2)
#define MAUSB_EP_HANDLE_RESP_VALID_MASK (1 << 3)

static const value_string mausb_eps_string[] = {
    { 0, "Unassigned" },
    { 1, "Active" },
    { 2, "Inactive" },
    { 3, "Halted" },
    { 0, NULL}
};

#define MAUSB_EPS_MASK 0x03

#define MAUSB_TFLAG_MASK   0xfc

#define MAUSB_TX_TYPE_CTRL (0 << 3)
#define MAUSB_TX_TYPE_ISOC (1 << 3)
#define MAUSB_TX_TYPE_BULK (2 << 3)
#define MAUSB_TX_TYPE_INTR (3 << 3)

#define MAUSB_TFLAG_OFFSET     2
#define MAUSB_TFLAG_ARQ  (1 << 0)
#define MAUSB_TFLAG_NEG  (1 << 1)
#define MAUSB_TFLAG_EOT  (1 << 2)
#define MAUSB_TFLAG_TRANSFER_TYPE (3 << 3)
#define MAUSB_TFLAG_RSVD (1 << 5)

static const value_string mausb_transfer_type_string[] = {
    { 0, "Control" },
    { 1, "Isochronous" },
    { 2, "Bulk" },
    { 3, "Interrupt" },
    { 0, NULL}
};

static const true_false_string tfs_ep_handle_resp_dir = { "IN", "OUT or Control" };

#define MAUSB_TRANSFER_TYPE_OFFSET 3 /* Offset from start of TFlags Field */
                                     /* (EPS not included) */
#define MAUSB_TRANSFER_TYPE_CTRL      (0 << MAUSB_TRANSFER_TYPE_OFFSET)
#define MAUSB_TRANSFER_TYPE_ISO       (1 << MAUSB_TRANSFER_TYPE_OFFSET)
#define MAUSB_TRANSFER_TYPE_BULK      (2 << MAUSB_TRANSFER_TYPE_OFFSET)
#define MAUSB_TRANSFER_TYPE_INTERRUPT (3 << MAUSB_TRANSFER_TYPE_OFFSET)

static const value_string mausb_cancel_transfer_status_string[] = {
    { 0, "Cancel Unsuccessful"},
    { 1, "Canceled before any data was moved"},
    { 2, "Canceled after some data was moved"},
    { 3, "Transfer completed"},
    { 4, "Transfer not yet received"},
    { 5, "Transfer cleared without any data moved"},
    { 0, NULL}
};

#define MAUSB_CANCEL_TRANSFER_STATUS_MASK 0x07

#define MAUSB_CLEAR_TRANSFERS_RESP_NUM_MASK 0x1f
#define MAUSB_CLEAR_TRANSFERS_STATUS_MASK 0x01
#define MAUSB_CLEAR_TRANSFERS_PARTIAL_MASK 0x02
#define MAUSB_CLEAR_TRANSFERS_RESP_BLOCK_RSVD_MASK 0xfffffffc


/* We need at least the first DWORD to determine the packet length (for TCP) */
#define MAUSB_MIN_LENGTH 4

#define MAUSB_MIN_MGMT_LENGTH 12
#define MAUSB_MIN_DATA_LENGTH 20
#define MAUSB_COMMON_LEN 9


/*** Packet parsing helper functions ***/

bool mausb_is_from_host(struct mausb_header *header)
{
    return (MAUSB_FLAG_HOST << MAUSB_FLAG_OFFSET) & header->ver_flags;
}

static bool mausb_is_mgmt_pkt(struct mausb_header *header)
{
    return MAUSB_PKT_TYPE_MGMT == (header->type & MAUSB_PKT_TYPE_MASK);
}

static bool mausb_is_data_pkt(struct mausb_header *header)
{
    return MAUSB_PKT_TYPE_DATA == (header->type & MAUSB_PKT_TYPE_MASK);
}

static bool mausb_is_transfer_req(struct mausb_header *header)
{
    return TransferReq == header->type;
}

static bool mausb_is_transfer_ack(struct mausb_header *header)
{
    return TransferAck == header->type;
}

static int8_t mausb_tx_type(struct mausb_header *header)
{
    return (header->u.s.eps_tflags >> MAUSB_TFLAG_OFFSET) & MAUSB_TFLAG_TRANSFER_TYPE;
}

static bool mausb_is_iso_pkt(struct mausb_header *header)
{
    return MAUSB_TX_TYPE_ISOC == mausb_tx_type(header);
}

static bool mausb_has_timestamp(struct mausb_header *header)
{
    return (MAUSB_FLAG_TIMESTAMP << MAUSB_FLAG_OFFSET) & header->ver_flags;
}

static bool mausb_has_mtd(struct mausb_header *header)
{
    return (MAUSB_IFLAG_MTD << MAUSB_IFLAG_OFFSET) & header->u.s.u1.num_headers_iflags;
}

static bool mausb_has_setup_data(struct mausb_header *header)
{
    if ((TransferReq == header->type ) &&
        (mausb_is_from_host(header)) &&
        (0 == header->u.s.seq_num) &&
        (MAUSB_TX_TYPE_CTRL == mausb_tx_type(header))) {

        return true;
    }
    return false;
}

static bool mausb_is_setup_response(struct mausb_header *header)
{
    if ((TransferResp == header->type) &&
        (!mausb_is_from_host(header)) &&
        (MAUSB_TX_TYPE_CTRL == mausb_tx_type(header))) {

        return true;
    }
    return false;
}

/*** EP Handle parsing helper functions */

uint8_t mausb_ep_handle_ep_d(uint16_t handle) {
    return (handle & MAUSB_EP_HANDLE_D) >> MAUSB_EP_HANDLE_D_OFFSET;
}

uint8_t mausb_ep_handle_ep_num(uint16_t handle) {
    return (handle & MAUSB_EP_HANDLE_EP_NUM) >> MAUSB_EP_HANDLE_EP_NUM_OFFSET;
}

uint8_t mausb_ep_handle_dev_addr(uint16_t handle) {
    return (handle & MAUSB_EP_HANDLE_DEV_ADDR) >> MAUSB_EP_HANDLE_DEV_ADDR_OFFSET;
}

uint8_t mausb_ep_handle_bus_num(uint16_t handle) {
    return (handle & MAUSB_EP_HANDLE_BUS_NUM) >> MAUSB_EP_HANDLE_BUS_NUM_OFFSET;
}

/* returns the length field of the MAUSB packet */
static unsigned mausb_get_pkt_len(packet_info *pinfo _U_, tvbuff_t *tvb,
                               int offset, void *data _U_)
{
    return tvb_get_letohs(tvb, offset + 2);
}

/* Initialize the subtree pointers */
static int ett_mausb;
static int ett_mausb_flags;
static int ett_mausb_ep_handle;
static int ett_mausb_tflags;
static int ett_mausb_iflags;
static int ett_mausb_present_time;
static int ett_mausb_timestamp;
static int ett_mgmt;
static int ett_dev_cap;
static int ett_clear_transfers_block;


#define USB_DT_EP_SIZE              7
#define USB_DT_SS_EP_COMP_SIZE      6
#define USB_DT_ISO_SSP_EP_COMP_SIZE 8

/* Size of EPHandleReq Descriptors */
#define MAUSB_EP_DES_SIZE 8
#define MAUSB_SS_EP_DES_SIZE 16
#define MAUSB_ISO_SSP_EP_DES_SIZE 24

/* EPHandleReq Descriptor Padding */
#define MAUSB_EP_DES_PAD         (MAUSB_EP_DES_SIZE - USB_DT_EP_SIZE)

#define MAUSB_SS_EP_DES_PAD      (MAUSB_SS_EP_DES_SIZE - \
        (USB_DT_EP_SIZE + USB_DT_SS_EP_COMP_SIZE))

#define MAUSB_ISO_SSP_EP_DES_PAD (MAUSB_ISO_SSP_EP_DES_SIZE - \
        (USB_DT_EP_SIZE + USB_DT_SS_EP_COMP_SIZE + USB_DT_ISO_SSP_EP_COMP_SIZE))


/* Size of EPHandleResp Descriptor */
#define MAUSB_SIZE_MAUSB_EP_DES 16


/* Size of EPHandleResp Descriptor */
#define MAUSB_SIZE_EP_HANDLE 2


/* Dissects an individual Device Capability Descriptor */
static uint16_t dissect_mausb_dev_cap_desc(proto_tree *tree, tvbuff_t *tvb,
                                          packet_info *pinfo, int16_t offset)
{
    uint8_t desc_len;
    uint8_t cap_type;
    int16_t desc_offset;
    proto_item *len_field;
    proto_tree *dev_cap_tree;

    desc_offset = offset;
    desc_len = tvb_get_uint8(tvb, desc_offset);
    cap_type = tvb_get_uint8(tvb, desc_offset + 1);

    dev_cap_tree = proto_tree_add_subtree(tree, tvb, desc_offset, desc_len,
        ett_dev_cap, NULL,
        val_to_str_const(cap_type, mausb_dev_cap_string, "Unknown Capability"));

    len_field = proto_tree_add_item(dev_cap_tree, hf_mausb_dev_cap_len,
        tvb, desc_offset, 1, ENC_LITTLE_ENDIAN);
    desc_offset += 1;

    proto_tree_add_item(dev_cap_tree, hf_mausb_dev_cap_type,
        tvb, desc_offset, 1, ENC_LITTLE_ENDIAN);
    desc_offset += 1;

    if (desc_len > 2) {

        /* TODO: dissect individual capabilities */
        switch (cap_type) {
        case SpeedCap:
        case PmanCap:
        case IsoCap:
        case SyncCap:
        case ContainerIDCap:
        case LinkSleepCap:
        default:
            proto_tree_add_item(dev_cap_tree, hf_mausb_dev_cap_generic,
            tvb, desc_offset, (desc_len - 2), ENC_NA);
            desc_offset += (desc_len - 2);

            break;
        }
    }

    /* Was this descriptor a different length than expected */
    if (desc_offset != offset + desc_len) {
        expert_add_info(pinfo, len_field, &ei_dev_cap_len);
    }

    return offset + desc_len;
}


/* Dissects a MAUSB capability response packet
 * also dissects Capability Descriptors
 */
static uint16_t dissect_mausb_mgmt_pkt_cap_resp(struct mausb_header *header,
       proto_tree *tree, tvbuff_t *tvb, packet_info *pinfo, int16_t offset)
{

    unsigned desc_len;
    uint8_t desc_count;
    proto_item *len_field;
    uint16_t loop_offset;
    int i;

    /* Fields present in all CapResp packets */
    proto_tree_add_item(tree, hf_mausb_cap_resp_num_ep,
        tvb, offset, 2, ENC_LITTLE_ENDIAN);
    offset += 2;

    proto_tree_add_item(tree, hf_mausb_cap_resp_num_dev,
        tvb, offset, 1, ENC_LITTLE_ENDIAN);
    offset += 1;

    proto_tree_add_item(tree, hf_mausb_cap_resp_num_stream,
        tvb, offset, 1, ENC_LITTLE_ENDIAN); /* really 5 bits */
    proto_tree_add_item(tree, hf_mausb_cap_resp_dev_type,
        tvb, offset, 1, ENC_LITTLE_ENDIAN); /* really 3 bits */
    offset += 1;

    proto_tree_add_item(tree, hf_mausb_cap_resp_desc_count,
        tvb, offset, 1, ENC_LITTLE_ENDIAN);
    desc_count = tvb_get_uint8(tvb, offset);
    offset += 1;

    len_field = proto_tree_add_item(tree, hf_mausb_cap_resp_desc_len,
        tvb, offset, 3, ENC_LITTLE_ENDIAN);
    desc_len = tvb_get_letoh24(tvb, offset);
    offset += 3;

    proto_tree_add_item(tree, hf_mausb_cap_resp_transfer_req,
        tvb, offset, 2, ENC_LITTLE_ENDIAN);
    offset += 2;

    proto_tree_add_item(tree, hf_mausb_cap_resp_mgmt_req,
        tvb, offset, 2, ENC_LITTLE_ENDIAN); /* really 12 bits */
    proto_tree_add_item(tree, hf_mausb_cap_resp_rsvd,
        tvb, offset, 2, ENC_LITTLE_ENDIAN); /* really 4 bits */
    offset += 2;

    /* Descriptors length longer than remainder of packet */
    if (offset + desc_len > header->length) {
        expert_add_info(pinfo, len_field, &ei_cap_resp_desc_len);
        desc_len = header->length - offset; /* to avoid overflows */
    }

    loop_offset = offset;

    /* dissect capability descriptors */
    for (i = 0; i < desc_count; i++) {
        loop_offset = dissect_mausb_dev_cap_desc(tree, tvb, pinfo, loop_offset);
    }

    /* were the descriptors a different length than expected */
    if (loop_offset != offset + desc_len) {
        expert_add_info(pinfo, len_field, &ei_dev_cap_resp_desc_len);
        desc_len = header->length - offset; /* to avoid overflows */
    }

    return offset + desc_len;
}

/* Dissects a MAUSB endpoint handle */
static int dissect_ep_handle(proto_tree *tree, tvbuff_t *tvb, int offset)
{

    proto_item *ti;
    proto_tree *ep_handle_tree;

    ti = proto_tree_add_item(tree, hf_mausb_ep_handle, tvb,
        offset, MAUSB_SIZE_EP_HANDLE, ENC_LITTLE_ENDIAN);

    ep_handle_tree = proto_item_add_subtree(ti, ett_mausb_ep_handle);
    proto_tree_add_item(ep_handle_tree, hf_mausb_ep_handle_d, tvb,
        offset, MAUSB_SIZE_EP_HANDLE, ENC_LITTLE_ENDIAN);
    proto_tree_add_item(ep_handle_tree, hf_mausb_ep_handle_ep_num, tvb,
        offset, MAUSB_SIZE_EP_HANDLE, ENC_LITTLE_ENDIAN);
    proto_tree_add_item(ep_handle_tree, hf_mausb_ep_handle_dev_addr, tvb,
        offset, MAUSB_SIZE_EP_HANDLE, ENC_LITTLE_ENDIAN);
    proto_tree_add_item(ep_handle_tree, hf_mausb_ep_handle_bus_num, tvb,
        offset, MAUSB_SIZE_EP_HANDLE, ENC_LITTLE_ENDIAN);

    return MAUSB_SIZE_EP_HANDLE;

}

/* dissects presentation time & subfields */
static void dissect_mausb_present_time(proto_tree *tree, tvbuff_t *tvb,
            int offset)
{
    proto_item *ti;
    proto_tree *present_time_tree;

    ti = proto_tree_add_item(tree, hf_mausb_present_time, tvb,
        offset, 4, ENC_LITTLE_ENDIAN);

    present_time_tree = proto_item_add_subtree(ti, ett_mausb_present_time);
    proto_tree_add_item(present_time_tree, hf_mausb_uframe, tvb,
        offset, 4, ENC_LITTLE_ENDIAN);
    proto_tree_add_item(present_time_tree, hf_mausb_frame, tvb,
        offset, 4, ENC_LITTLE_ENDIAN);

}

static void dissect_mausb_timestamp(proto_tree *tree, tvbuff_t *tvb,
            int offset)
{
    proto_item *ti;
    proto_tree *timestamp_tree;

    ti = proto_tree_add_item(tree, hf_mausb_timestamp, tvb,
        offset, 4, ENC_LITTLE_ENDIAN);

    timestamp_tree = proto_item_add_subtree(ti, ett_mausb_timestamp);
    proto_tree_add_item(timestamp_tree, hf_mausb_delta, tvb,
        offset, 4, ENC_LITTLE_ENDIAN);
    proto_tree_add_item(timestamp_tree, hf_mausb_nom_interval, tvb,
        offset, 4, ENC_LITTLE_ENDIAN);

}

/* gets the size of the endpoint descriptors in a EPHandleReq packet */
static uint8_t mausb_get_size_ep_des(tvbuff_t *tvb, int offset)
{
    uint8_t size_ep_des = 0;
    uint16_t temp_buffer = 0; /* for storing the offset data */

    /* grab the 2 bytes with the size field */
    temp_buffer = tvb_get_letohs(tvb, offset);

    /* mask & shift the size field */
    temp_buffer = temp_buffer & MAUSB_MGMT_SIZE_EP_DES_MASK;
    size_ep_des = (temp_buffer >> MAUSB_MGMT_SIZE_EP_DES_OFFSET);

    return size_ep_des;
}

/* dissect an individual block for ClearTransfers */
static uint16_t dissect_clear_transfers_block(proto_tree *tree,
               tvbuff_t *tvb, int16_t offset, bool req)
{
    proto_item *ti;
    proto_tree *block_tree;

    if (req) {
        ti = proto_tree_add_item(tree, hf_mausb_clear_transfers_info_block,
                                 tvb, offset, 8, ENC_NA);
    } else {
        ti = proto_tree_add_item(tree, hf_mausb_clear_transfers_status_block,
                                 tvb, offset, 16, ENC_NA);
    }

    block_tree = proto_item_add_subtree(ti, ett_clear_transfers_block);


    /* EP Handle */
    offset += dissect_ep_handle(block_tree, tvb, offset);

    /* Stream ID */
    proto_tree_add_item(block_tree, hf_mausb_stream_id, tvb, offset, 2,
                        ENC_LITTLE_ENDIAN);
    offset += 2;

    if (req) {
        /* Start Request ID */
        proto_tree_add_item(block_tree, hf_mausb_clear_transfers_start_req_id,
                            tvb, offset, 1, ENC_LITTLE_ENDIAN);
        offset += 1;

        /* Rsvd */
        proto_tree_add_item(block_tree, hf_mausb_clear_transfers_req_block_rsvd,
                            tvb, offset, 3, ENC_NA);
        offset += 3;

    } else {
        /* Cancel Status */
        proto_tree_add_item(block_tree, hf_mausb_clear_transfers_status,
                            tvb, offset, 4, ENC_LITTLE_ENDIAN);
        /* Partial Delivery */
        proto_tree_add_item(block_tree, hf_mausb_clear_transfers_partial,
                            tvb, offset, 4, ENC_LITTLE_ENDIAN);
        /* Rsvd */
        proto_tree_add_item(block_tree, hf_mausb_clear_transfers_resp_block_rsvd,
                            tvb, offset, 4, ENC_LITTLE_ENDIAN);
        offset += 4;

        /* Last Request ID */
        proto_tree_add_item(block_tree, hf_mausb_clear_transfers_last_req_id,
                            tvb, offset, 1, ENC_LITTLE_ENDIAN);
        offset += 1;

        /* Delivered Sequence Number */
        proto_tree_add_item(block_tree, hf_mausb_cancel_transfer_seq_num, tvb,
                            offset, 3, ENC_LITTLE_ENDIAN);
        offset += 3;
        /* Delivered Byte Offset */
        proto_tree_add_item(block_tree, hf_mausb_cancel_transfer_byte_offset,
                            tvb, offset, 4, ENC_LITTLE_ENDIAN);
        offset += 4;
    }

    return offset;
}

/* dissects portions of a MA USB packet specific to ClearTransfers packets */
static uint16_t dissect_mausb_mgmt_pkt_clear_transfers(proto_tree *tree,
               tvbuff_t *tvb, int16_t offset, bool req)
{
    uint8_t num_block;
    int i;

    num_block = tvb_get_uint8(tvb, offset);
    if (req) {
        /* Number of entries */
        proto_tree_add_item(tree, hf_mausb_clear_transfers_req_num, tvb,
                            offset, 1, ENC_LITTLE_ENDIAN);
        offset += 1;

        /* Rsvd */
        proto_tree_add_item(tree, hf_mausb_clear_transfers_req_rsvd, tvb,
                            offset, 3, ENC_NA);
        offset += 3;

    } else {
        num_block &= MAUSB_MGMT_CLEAR_TRANSFER_RESP_NUM_MASK;

        /* Number of entries */
        proto_tree_add_item(tree, hf_mausb_clear_transfers_resp_num, tvb,
                            offset, 1, ENC_LITTLE_ENDIAN);
        /* Rsvd */
        proto_tree_add_item(tree, hf_mausb_clear_transfers_resp_rsvd, tvb,
                            offset, 1, ENC_LITTLE_ENDIAN);
        offset += 4;
    }

    for (i = 0; i < num_block; i++) {
        offset = dissect_clear_transfers_block(tree, tvb, offset, req);
    }

    return offset;
}

/* dissects portions of a MA USB packet specific to Endpoint Handle Request packets */
static uint16_t dissect_mausb_mgmt_pkt_ep_handle( proto_tree *tree, tvbuff_t *tvb,
            packet_info *pinfo, int16_t start, bool req, bool del)
{
    urb_info_t urb;
    proto_item *size_field = NULL;
    uint16_t offset = start;
    uint16_t loop_offset;
    uint8_t num_ep;
    uint8_t size_ep_des;
    uint8_t last_ep_type = ENDPOINT_TYPE_NOT_SET;
    int i;

    memset(&urb,  0, sizeof(urb_info_t));

    num_ep = tvb_get_uint8(tvb, offset) & MAUSB_MGMT_NUM_EP_DES_MASK;

    if (!del) {
        proto_tree_add_item(tree, hf_mausb_mgmt_ep_des_num, tvb,
            offset, 1, ENC_LITTLE_ENDIAN); /* really 5 bits */
    } else {
        proto_tree_add_item(tree, hf_mausb_mgmt_ep_handle_num, tvb,
            offset, 1, ENC_LITTLE_ENDIAN); /* really 5 bits */
    }

     if (req && !del) {

        size_ep_des = mausb_get_size_ep_des(tvb, offset);
        size_field = proto_tree_add_item(tree, hf_mausb_mgmt_ep_des_size, tvb,
            offset, 2, ENC_LITTLE_ENDIAN); /* really 6 bits over a byte boundary */
        offset += 1;

        /* Padding to DWORD */
        proto_tree_add_item(tree, hf_mausb_mgmt_ep_des_pad, tvb,
            offset, 3, ENC_NA);
        offset += 3;

    } else if (!req && !del) {
        size_ep_des = MAUSB_SIZE_MAUSB_EP_DES;
        proto_tree_add_item(tree, hf_mausb_mgmt_ep_handle_pad, tvb,
            offset, 4, ENC_NA); /* really 5 bits */
        /* Padding to DWORD */
        offset += 4;

    } else { /* If it is an EPHandleDelete Req or Resp */
        size_ep_des = MAUSB_SIZE_EP_HANDLE;
        /* Padding to DWORD */
        proto_tree_add_item(tree, hf_mausb_mgmt_ep_handle_pad, tvb,
            offset, 4, ENC_NA);
        offset += 4; /* Padding to DWORD */

    }

    /* For every entry */
    for (i = 0; i < num_ep; ++i) {
        loop_offset = offset;

        /* If it is an EPHandleDelete Req or Resp */
        if (del) {
            loop_offset += dissect_ep_handle(tree, tvb, loop_offset);

        } else if (req) {

            /* Standard USB Endpoint Descriptor */
            dissect_usb_endpoint_descriptor(pinfo, tree, tvb, loop_offset,
                    &urb, &last_ep_type, USB_SPEED_UNKNOWN);
            loop_offset += USB_DT_EP_SIZE;

            /* If there are more descriptors to read */
            if (MAUSB_EP_DES_SIZE < size_ep_des) {
                /* TODO: Dissector for SS EP Companion Descriptors */
                dissect_usb_unknown_descriptor(pinfo, tree,
                        tvb, loop_offset, &urb);
                loop_offset += USB_DT_SS_EP_COMP_SIZE;

                if (MAUSB_SS_EP_DES_SIZE < size_ep_des) {
                    /* TODO: Dissector for SSP ISO EP Companion Descriptors */
                    loop_offset += dissect_usb_unknown_descriptor(pinfo, tree,
                            tvb, loop_offset, &urb);

                    /* Pad to a DWORD */
                    proto_tree_add_item(tree, hf_mausb_ep_handle_req_pad, tvb,
                        loop_offset, MAUSB_ISO_SSP_EP_DES_PAD, ENC_NA);
                    loop_offset += MAUSB_ISO_SSP_EP_DES_PAD;

                } else {
                    /* Pad to a DWORD */
                    proto_tree_add_item(tree, hf_mausb_ep_handle_req_pad, tvb,
                        loop_offset, MAUSB_SS_EP_DES_PAD, ENC_NA);
                    loop_offset += MAUSB_SS_EP_DES_PAD;
                }

            } else {
                /* Pad to a DWORD */
                proto_tree_add_item(tree, hf_mausb_ep_handle_req_pad, tvb,
                    loop_offset, MAUSB_EP_DES_PAD, ENC_NA);
                loop_offset += MAUSB_EP_DES_PAD;
            }

        } else { /* IE: it's a EPHandleResp */
            /* EP Handle */
            loop_offset += dissect_ep_handle(tree, tvb, loop_offset);

            /* direction */
            proto_tree_add_item(tree, hf_mausb_ep_handle_resp_dir, tvb,
                loop_offset, 1, ENC_LITTLE_ENDIAN);

            /* isochronous */
            proto_tree_add_item(tree, hf_mausb_ep_handle_resp_iso, tvb,
                loop_offset, 1, ENC_LITTLE_ENDIAN);

            /* L-managed transfers */
            proto_tree_add_item(tree, hf_mausb_ep_handle_resp_lman, tvb,
                loop_offset, 1, ENC_LITTLE_ENDIAN);

            /* valid handle bit */
            proto_tree_add_item(tree, hf_mausb_ep_handle_resp_valid, tvb,
                loop_offset, 1, ENC_LITTLE_ENDIAN);
            loop_offset += 2; /* 4 bit flags + 12 reserved bits */

            /* credit consumption unit */
            proto_tree_add_item(tree, hf_mausb_ep_handle_resp_ccu, tvb,
                loop_offset, 2, ENC_LITTLE_ENDIAN);
            loop_offset += 2;

            loop_offset += 2; /* 2 bytes reserved */

            /* buffer size (in bytes) */
            proto_tree_add_item(tree, hf_mausb_ep_handle_resp_buf_size, tvb,
                loop_offset, 4, ENC_LITTLE_ENDIAN);
            loop_offset += 4;


            /* max iso programming delay (in uSec) */
            proto_tree_add_item(tree, hf_mausb_ep_handle_resp_iso_prog_dly, tvb,
                loop_offset, 2, ENC_LITTLE_ENDIAN);
            loop_offset += 2;

            /* max iso response delay (in uSec) */
            proto_tree_add_item(tree, hf_mausb_ep_handle_resp_iso_resp_dly, tvb,
                loop_offset, 2, ENC_LITTLE_ENDIAN);
            loop_offset += 2;
        }


        offset += size_ep_des;

        if (req && !del && loop_offset != offset){
            expert_add_info(pinfo, size_field, &ei_ep_handle_len);
        }

    }

    return offset;

}

/* dissects portions of a MA USB packet specific to CancelTransfer packets */
static uint16_t dissect_mausb_mgmt_pkt_cancel_transfer( proto_tree *tree,
        tvbuff_t *tvb, int offset, bool req)
{

    uint8_t status;

    offset += dissect_ep_handle(tree, tvb, offset);

    proto_tree_add_item(tree, hf_mausb_stream_id, tvb, offset, 2,
                        ENC_LITTLE_ENDIAN);
    offset += 2;

    proto_tree_add_item(tree, hf_mausb_req_id, tvb, offset, 1,
                        ENC_LITTLE_ENDIAN);
    offset += 1;

    if (req) {
        proto_tree_add_item(tree, hf_mausb_cancel_transfer_rsvd, tvb, offset, 3,
                            ENC_NA);
        offset += 3;

        return offset;
    } /* else resp */

    status = tvb_get_uint8(tvb, offset) |
                       MAUSB_CANCEL_TRANSFER_STATUS_MASK;

    proto_tree_add_item(tree, hf_mausb_cancel_transfer_status, tvb, offset, 3,
                        ENC_LITTLE_ENDIAN);

    proto_tree_add_item(tree, hf_mausb_cancel_transfer_rsvd_2, tvb, offset, 3,
                        ENC_LITTLE_ENDIAN);
    /* Reserved */
    offset += 3;

    /* if some data was moved */
    if (2 == status) {
        /* TODO: sequence number reserved for INs */
        proto_tree_add_item(tree, hf_mausb_cancel_transfer_seq_num, tvb, offset,
                            3, ENC_LITTLE_ENDIAN);
        offset += 3;

        proto_tree_add_item(tree, hf_mausb_cancel_transfer_rsvd, tvb, offset, 1,
                            ENC_NA);
        offset += 1;

        proto_tree_add_item(tree, hf_mausb_cancel_transfer_byte_offset, tvb,
                            offset, 4, ENC_LITTLE_ENDIAN);
        offset += 4;

    } else {
        proto_tree_add_item(tree, hf_mausb_cancel_transfer_rsvd, tvb, offset, 8,
                            ENC_NA);
        offset += 8;
    }

    return offset;

}

/* dissects portions of a MA USB packet specific to particular management packets */
static uint16_t dissect_mausb_mgmt_pkt_flds(struct mausb_header *header,
        proto_tree *tree, tvbuff_t *tvb,
        packet_info *pinfo, int16_t start)
{

    proto_item *ti;
    proto_tree *mgmt_tree;
    uint16_t offset = start;
    int type_spec_len = tvb_reported_length(tvb) - start;

    if (0 > type_spec_len) {
        expert_add_info(pinfo, tree, &ei_mgmt_type_spec_len_short);
        return offset;
    }

    ti = proto_tree_add_item(tree, hf_mausb_mgmt_type_spec, tvb,
                             offset, type_spec_len, ENC_NA);

    mgmt_tree = proto_item_add_subtree(ti, ett_mgmt);

    switch (header->type) {

    /* subtypes with variable length additional data */
    case CapResp:
        offset = dissect_mausb_mgmt_pkt_cap_resp(header, mgmt_tree, tvb, pinfo, offset);
        break;
    case EPHandleReq:
        offset = dissect_mausb_mgmt_pkt_ep_handle(mgmt_tree, tvb, pinfo,
                                                  offset, true, false);
    break;

    case EPHandleResp:
        offset = dissect_mausb_mgmt_pkt_ep_handle(mgmt_tree, tvb, pinfo,
                                                  offset, false, false);
    break;

    /* TODO: Dissect type-specific management packet fields */
    case EPActivateReq:
    case EPActivateResp:
    case EPInactivateReq:
    case EPInactivateResp:
    case EPResetReq:
    case EPResetResp:
        proto_tree_add_item(mgmt_tree, hf_mausb_mgmt_type_spec_generic,
                            tvb, offset, type_spec_len, ENC_NA);
        offset += type_spec_len;
        break;
    case ClearTransfersReq:
        offset = dissect_mausb_mgmt_pkt_clear_transfers(mgmt_tree, tvb, offset, true);
        break;
    case ClearTransfersResp:
        offset = dissect_mausb_mgmt_pkt_clear_transfers(mgmt_tree, tvb, offset, false);
        break;
    case EPHandleDeleteReq:
        offset = dissect_mausb_mgmt_pkt_ep_handle(mgmt_tree, tvb, pinfo,
                                                  offset, true, true);
    break;
    case EPHandleDeleteResp:
        offset = dissect_mausb_mgmt_pkt_ep_handle(mgmt_tree, tvb, pinfo,
                                                  offset, false, true);
    break;
    case ModifyEP0Resp:
    case EPCloseStreamResp:
    case USBDevResetReq:
    case USBDevResetResp:
    case EPOpenStreamResp:
    case VendorSpecificReq:
    case VendorSpecificResp:
        /* FALLTHROUGH */

    /* subtypes with constant length additional data */
    case CapReq:
    case USBDevHandleReq:
    case USBDevHandleResp:
    case ModifyEP0Req:
    case SetUSBDevAddrReq:
    case SetUSBDevAddrResp:
    case UpdateDevReq:
    case SynchReq:
    case EPCloseStreamReq:
        proto_tree_add_item(mgmt_tree, hf_mausb_mgmt_type_spec_generic,
                            tvb, offset, type_spec_len, ENC_NA);
        offset += type_spec_len;
        break;

    case CancelTransferReq:
        offset = dissect_mausb_mgmt_pkt_cancel_transfer(mgmt_tree, tvb, offset,
                                                        true);
        break;
    case CancelTransferResp:
        offset = dissect_mausb_mgmt_pkt_cancel_transfer(mgmt_tree, tvb, offset,
                                                        false);
        break;
    case EPOpenStreamReq:

        proto_tree_add_item(mgmt_tree, hf_mausb_mgmt_type_spec_generic,
                            tvb, offset, type_spec_len, ENC_NA);
        offset += type_spec_len;
        break;


    /* Management packets with no additional data */
    case DevResetReq:
    case DevResetResp:
    case UpdateDevResp:
    case USBDevDisconnectReq:
    case USBDevDisconnectResp:
    case SleepReq:
    case SleepResp:
    case WakeReq:
    case WakeResp:
    case PingReq:
    case PingResp:
    case DevDisconnectReq:
    case DevDisconnectResp:
    case DevInitDisconnectReq:
    case DevInitDisconnectResp:
    case SynchResp:
    break;

    default:
        expert_add_info(pinfo, mgmt_tree, &ei_mgmt_type_undef);
    break;

    }


    if (offset < tvb_reported_length(tvb)) {
        expert_add_info(pinfo, mgmt_tree, &ei_mgmt_type_spec_len_long);
    }

    return offset;
}

void mausb_set_urb_info(urb_info_t *urb, struct mausb_header *header)
{
        urb->is_request = mausb_is_transfer_req(header);
        urb->bus_id = mausb_ep_handle_bus_num(header->handle);
        urb->device_address = mausb_ep_handle_dev_addr(header->handle);
        urb->direction = mausb_is_from_host(header);
        urb->endpoint = mausb_ep_handle_ep_num(header->handle);
        if (mausb_ep_handle_ep_d(header->handle)) {
            /* IN endpoint */
            urb->endpoint |= 0x80;
        }
        urb->is_setup = mausb_has_setup_data(header) ||
                                  mausb_is_setup_response(header);
        switch (mausb_tx_type(header)) {
        case MAUSB_TX_TYPE_CTRL:
                urb->transfer_type = URB_CONTROL;
                break;
        case MAUSB_TX_TYPE_ISOC:
                urb->transfer_type = URB_ISOCHRONOUS;
                break;
        case MAUSB_TX_TYPE_BULK:
                urb->transfer_type = URB_BULK;
                break;
        case MAUSB_TX_TYPE_INTR:
                urb->transfer_type = URB_INTERRUPT;
                break;
        default:
                urb->transfer_type = URB_UNKNOWN;
                break;
        }
}

/* Used to detect multiple MA Packets in a single TCP packet */
/* Not used for MA Packets in SNAP Packets */
static int mausb_num_pdus;


/* dissect fields common to all MAUSB packet types */
static int
dissect_mausb_pkt_common(tvbuff_t *tvb, int offset, packet_info *pinfo,
        proto_tree *mausb_tree, struct mausb_header *header)
{
    proto_item *len_field;

    /* MAUSB Protocol Version */
    header->ver_flags = tvb_get_uint8(tvb, offset);
    proto_tree_add_item(mausb_tree, hf_mausb_version, tvb,
            offset, 1, ENC_LITTLE_ENDIAN);

    /* Flags */
    proto_tree_add_bitmask(mausb_tree, tvb, offset, hf_mausb_flags,
            ett_mausb_flags, mausb_flag_fields, ENC_LITTLE_ENDIAN);
    offset += 1;

    /* Packet Type */
    header->type = tvb_get_uint8(tvb, offset);
    col_append_str(pinfo->cinfo, COL_INFO, val_to_str(pinfo->pool, header->type, mausb_type_string, "%d"));
    proto_tree_add_item(mausb_tree, hf_mausb_type, tvb,
            offset, 1, ENC_LITTLE_ENDIAN);
    offset += 1;

    /* Packet Length */
    header->length = tvb_get_letohs(tvb, offset);
    col_append_fstr(pinfo->cinfo, COL_INFO, " Length=%u", header->length);
    len_field = proto_tree_add_item(mausb_tree, hf_mausb_length, tvb,
            offset, 2, ENC_LITTLE_ENDIAN);
    offset += 2;

    /* Check to see if length field is valid */
    if (tvb_reported_length(tvb) != header->length) {
        expert_add_info(pinfo, len_field, &ei_len);
    }

    /* Is the next field a device handle or an endpoint handle */
    header->handle = tvb_get_letohs(tvb, offset);

    if (mausb_is_mgmt_pkt(header)) {
        proto_tree_add_item(mausb_tree, hf_mausb_dev_handle, tvb,
              offset, 2, ENC_LITTLE_ENDIAN);
        offset += 2;
    } else {
        offset += dissect_ep_handle(mausb_tree, tvb, offset);
    }

    /* MA Device Address */
    header->ma_dev_addr = tvb_get_uint8(tvb, offset);
    proto_tree_add_item(mausb_tree, hf_mausb_ma_dev_addr, tvb,
            offset, 1, ENC_LITTLE_ENDIAN);
    offset += 1;

    /* SSID */
    header->mass_id = tvb_get_uint8(tvb, offset);
    proto_tree_add_item(mausb_tree, hf_mausb_ssid, tvb,
            offset, 1, ENC_LITTLE_ENDIAN);
    offset += 1;

    /* Status */
    header->status = tvb_get_uint8(tvb, offset);
    proto_tree_add_item(mausb_tree, hf_mausb_status, tvb,
            offset, 1, ENC_LITTLE_ENDIAN);
    offset += 1;

    return offset;
}

/* dissect datapacket specific values */
static int
dissect_mausb_pkt_data(tvbuff_t *tvb, int offset, packet_info *pinfo,
        proto_tree *mausb_tree, struct mausb_header *header)
{
    /* EPS */
    header->u.s.eps_tflags = tvb_get_uint8(tvb, offset);
    if (mausb_is_from_host(header)) {
        proto_tree_add_item(mausb_tree, hf_mausb_eps_rsvd, tvb,
            offset, 1, ENC_LITTLE_ENDIAN);
    } else {
        proto_tree_add_item(mausb_tree, hf_mausb_eps, tvb,
            offset, 1, ENC_LITTLE_ENDIAN);
    }

    /* T-Flags */
    proto_tree_add_bitmask(mausb_tree, tvb, offset, hf_mausb_tflags,
            ett_mausb_tflags, mausb_tflag_fields, ENC_LITTLE_ENDIAN);
    offset += 1;

    if (mausb_is_iso_pkt(header)) {
        /* Number of Headers */
        header->u.s.u1.num_headers_iflags = tvb_get_letohs(tvb, offset);
        proto_tree_add_item(mausb_tree, hf_mausb_num_iso_hdr, tvb,
            offset, 2, ENC_LITTLE_ENDIAN);

        /* I-Flags */
        proto_tree_add_bitmask(mausb_tree, tvb, offset, hf_mausb_iflags,
                ett_mausb_iflags, mausb_iflag_fields, ENC_LITTLE_ENDIAN);

    } else {
        /* Stream ID */
        header->u.s.u1.stream_id = tvb_get_letohs(tvb, offset);
        proto_tree_add_item(mausb_tree, hf_mausb_stream_id, tvb,
            offset, 2, ENC_LITTLE_ENDIAN);
    }
    offset += 2;

    /* Sequence Number */
    header->u.s.seq_num = tvb_get_letoh24(tvb, offset);
    col_append_fstr(pinfo->cinfo, COL_INFO, " SeqNum=%u", header->u.s.seq_num);
    proto_tree_add_item(mausb_tree, hf_mausb_seq_num, tvb,
        offset, 3, ENC_LITTLE_ENDIAN);
    offset += 3;

    /* Request ID */
    header->u.s.req_id = tvb_get_uint8(tvb, offset);
    col_append_fstr(pinfo->cinfo, COL_INFO, " ReqID=%u", header->u.s.req_id);
    proto_tree_add_item(mausb_tree, hf_mausb_req_id, tvb,
        offset, 1, ENC_LITTLE_ENDIAN);
    offset += 1;

    if (mausb_is_iso_pkt(header)) {
        /* Presentation Time */
        header->u.s.u2.present_time_num_seg = tvb_get_letohl(tvb, offset);
        dissect_mausb_present_time(mausb_tree, tvb, offset);

        /* Number of Segments */
        proto_tree_add_item(mausb_tree, hf_mausb_num_segs, tvb,
            offset, 4, ENC_LITTLE_ENDIAN);
        offset += 4;

        /* MA USB Timestamp */
        if (mausb_has_timestamp(header)) {
            header->u.s.timestamp = tvb_get_letohl(tvb, offset);
            dissect_mausb_timestamp(mausb_tree, tvb, offset);
            offset += 4;
        }

        /* Media Time/Transmission Delay */
        if (mausb_has_mtd(header)) {
            header->u.s.tx_dly = tvb_get_letohl(tvb, offset);
            proto_tree_add_item(mausb_tree, hf_mausb_mtd, tvb,
                offset, 4, ENC_LITTLE_ENDIAN);
            offset += 4;
        }

    /* Not Iso */
    } else {
        /* Remaining Size/Credit */
        header->u.s.u2.credit = tvb_get_letohl(tvb, offset);
        proto_tree_add_item(mausb_tree, hf_mausb_rem_size_credit, tvb,
            offset, 4, ENC_LITTLE_ENDIAN);
        offset += 4;
    }

    return offset;
}

/* Code to actually dissect the packets */
static int
dissect_mausb_pkt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
        void *data _U_)
{
    /* Set up structures needed to add the protocol subtree and manage it */
    proto_item *ti;
    proto_tree *mausb_tree;
    /* Other misc. local variables. */
    struct mausb_header header;
    unsigned offset = 0;

    memset(&header, 0, sizeof(struct mausb_header));

    /* Set the Protocol column to the constant string of mausb */
    col_set_str(pinfo->cinfo, COL_PROTOCOL, "MAUSB");

    mausb_num_pdus++;

    col_set_str(pinfo->cinfo, COL_INFO, "[");
    col_set_fence(pinfo->cinfo, COL_INFO);

    /*** PROTOCOL TREE ***/

    /* create display subtree for the protocol */
    ti = proto_tree_add_item(tree, proto_mausb, tvb, 0,
                mausb_get_pkt_len(pinfo, tvb, offset, NULL), ENC_NA);

    mausb_tree = proto_item_add_subtree(ti, ett_mausb);

    /* Add an item to the subtree, see section 1.5 of README.dissector for more
     * information. */

    offset = dissect_mausb_pkt_common(tvb, offset, pinfo, mausb_tree, &header);

    if (mausb_is_mgmt_pkt(&header)) {

        /* Dialog Token */
        header.u.token = tvb_get_letohs(tvb, 9) & MAUSB_TOKEN_MASK;
        col_append_fstr(pinfo->cinfo, COL_INFO, " Token=%u", header.u.token);
        proto_tree_add_item(mausb_tree, hf_mausb_token, tvb,
            offset, 2, ENC_LITTLE_ENDIAN); /* Really 10 bits */
        offset += 1; /* token */

        /* Padding to a DWORD */
        proto_tree_add_item(mausb_tree, hf_mausb_mgmt_pad, tvb,
            offset, 2, ENC_LITTLE_ENDIAN); /* Really 14 bits */

        offset += 2; /* DWORD*/

        /* Dissect additional management fields (when applicable) */
        if (offset < header.length) {
            dissect_mausb_mgmt_pkt_flds(&header, mausb_tree, tvb, pinfo, offset);
        }

    }
    else if (mausb_is_data_pkt(&header)) {
        dissect_mausb_pkt_data(tvb, offset, pinfo, mausb_tree, &header);

        if (!mausb_is_transfer_ack(&header)) {
            dissect_usb_common(tvb, pinfo, tree, USB_HEADER_MAUSB, &header);
        }
    }

    col_append_str(pinfo->cinfo, COL_INFO, "]");
    col_set_fence(pinfo->cinfo, COL_INFO);

    return header.length;
}

/* Code to dissect the stream */
static int
dissect_mausb(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{

    mausb_num_pdus = 0;

    tcp_dissect_pdus(tvb, pinfo, tree, true, MAUSB_MIN_LENGTH,
            mausb_get_pkt_len, dissect_mausb_pkt, data);

    if (1 < mausb_num_pdus) {
        col_clear_fence(pinfo->cinfo, COL_INFO);
        col_prepend_fstr(pinfo->cinfo, COL_INFO, "[%i packets] ", mausb_num_pdus);
    }

    return tvb_reported_length(tvb);
}


/* Register the protocol with Wireshark.
 */
void
proto_register_mausb(void)
{

    static hf_register_info hf[] = {
        { &hf_mausb_version,
            { "Version", "mausb.version", FT_UINT8, BASE_DEC,
              VALS(mausb_version_string), MAUSB_VERSION_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_flags,
            { "Flags", "mausb.flags", FT_UINT8, BASE_HEX,
              NULL, MAUSB_FLAG_MASK, NULL, HFILL
            }
        },

        /* Flag Subfields */
        { &hf_mausb_flag_host,
            { "Host", "mausb.flags.host", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), (MAUSB_FLAG_HOST << MAUSB_FLAG_OFFSET),
              NULL, HFILL
            }
        },
        { &hf_mausb_flag_retry,
            { "Retry", "mausb.flags.retry", FT_BOOLEAN, 8,
              TFS(&tfs_yes_no), (MAUSB_FLAG_RETRY << MAUSB_FLAG_OFFSET),
              NULL, HFILL
            }
        },
        { &hf_mausb_flag_timestamp,
            { "Timestamp", "mausb.flags.timestamp", FT_BOOLEAN, 8,
              TFS(&tfs_present_not_present),
              (MAUSB_FLAG_TIMESTAMP << MAUSB_FLAG_OFFSET),
              NULL, HFILL
            }
        },
        { &hf_mausb_flag_reserved,
            { "Reserved", "mausb.flags.reserved", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), (MAUSB_FLAG_RESERVED << MAUSB_FLAG_OFFSET),
              NULL, HFILL
            }
        },


        { &hf_mausb_type,
            { "Type", "mausb.type", FT_UINT8, BASE_HEX,
              VALS(mausb_type_string), 0, NULL, HFILL
            }
        },
        { &hf_mausb_length,
            { "Length", "mausb.length", FT_UINT16, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_dev_handle,
            { "Device Handle", "mausb.dev_handle", FT_UINT16, BASE_HEX,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle,
            { "Endpoint Handle", "mausb.ep_handle", FT_UINT16, BASE_HEX,
              NULL, 0, NULL, HFILL
            }
        },

        /* EP Handle Subfields */
        { &hf_mausb_ep_handle_d,
            { "Direction", "mausb.ep_handle.d", FT_BOOLEAN, 16,
              TFS(&tfs_endpoint_direction), MAUSB_EP_HANDLE_D, NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle_ep_num,
            { "Endpoint Number", "mausb.ep_handle.ep_num", FT_UINT16, BASE_DEC,
              NULL, MAUSB_EP_HANDLE_EP_NUM, NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle_dev_addr,
            { "USB Device Address", "mausb.ep_handle.dev_addr", FT_UINT16, BASE_DEC,
              NULL, MAUSB_EP_HANDLE_DEV_ADDR, NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle_bus_num,
            { "USB Bus Number", "mausb.ep_handle.bus_num", FT_UINT16, BASE_DEC,
              NULL, MAUSB_EP_HANDLE_BUS_NUM, NULL, HFILL
            }
        },


        { &hf_mausb_ma_dev_addr,
            { "MA Device Address", "mausb.ma_dev_addr", FT_UINT8, BASE_HEX,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_ssid,
            { "Service Set ID", "mausb.ssid", FT_UINT8, BASE_HEX,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_status,
            { "Status", "mausb.status", FT_UINT8, BASE_DEC,
              VALS(mausb_status_string), 0, NULL, HFILL
            }
        },

        /* Management Packets Only */
        { &hf_mausb_token,
            { "Token", "mausb.token", FT_UINT16, BASE_DEC,
              NULL, MAUSB_TOKEN_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_mgmt_pad,
            { "Padding to a DWORD", "mausb.mgmt_pad",
              FT_UINT16, BASE_HEX, NULL, MAUSB_MGMT_PAD_MASK,
              NULL, HFILL
            }
        },
        { &hf_mausb_mgmt_type_spec,
            { "Type-specific management packet fields", "mausb.mgmt_flds",
              FT_NONE, 0, NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_mgmt_type_spec_generic,
            { "Type-specific management packet fields", "mausb.mgmt_flds.generic",
              FT_NONE, 0, NULL, 0, NULL, HFILL
            }
        },

        /* Data Packets Only */
        { &hf_mausb_eps,
            { "EP Status", "mausb.eps", FT_UINT8, BASE_HEX,
              VALS(mausb_eps_string), MAUSB_EPS_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_eps_rsvd,
            { "EP Status", "mausb.eps.reserved", FT_UINT8, BASE_HEX,
              NULL, MAUSB_EPS_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_tflags,
            { "Transfer Flags", "mausb.tflag", FT_UINT8, BASE_HEX,
              NULL, MAUSB_TFLAG_MASK, NULL, HFILL
            }
        },

        /* T-Flag Subfields */
        { &hf_mausb_tflag_arq,
            { "ARQ", "mausb.tflag.arq", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), MAUSB_TFLAG_ARQ << MAUSB_TFLAG_OFFSET,
              NULL, HFILL
            }
        },
        { &hf_mausb_tflag_neg,
            { "NEG", "mausb.tflag.neg", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), MAUSB_TFLAG_NEG << MAUSB_TFLAG_OFFSET,
              NULL, HFILL
            }
        },
        { &hf_mausb_tflag_eot,
            { "EoT", "mausb.tflag.eot", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), MAUSB_TFLAG_EOT << MAUSB_TFLAG_OFFSET,
              NULL, HFILL
            }
        },
        { &hf_mausb_tflag_type,
            { "Transfer Type", "mausb.tflag.type", FT_UINT8, BASE_HEX,
              VALS(mausb_transfer_type_string),
              MAUSB_TFLAG_TRANSFER_TYPE << MAUSB_TFLAG_OFFSET,
              NULL, HFILL
            }
        },
        { &hf_mausb_tflag_rsvd,
            { "Reserved", "mausb.tflag.rsvd", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), MAUSB_TFLAG_RSVD << MAUSB_TFLAG_OFFSET,
              NULL, HFILL
            }
        },


        { &hf_mausb_num_iso_hdr,
            { "Number of Iso Headers", "mausb.numisohdr", FT_UINT16, BASE_DEC,
              NULL, MAUSB_NUM_ISO_HDR_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_iflags,
            { "Isochronous Flags", "mausb.iflag", FT_UINT16, BASE_HEX,
              NULL, MAUSB_IFLAG_MASK, NULL, HFILL
            }
        },

        /* I-Flag Subfields */
        { &hf_mausb_iflag_mtd,
            { "MTD Valid", "mausb.iflag.mtd", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), MAUSB_IFLAG_MTD << MAUSB_IFLAG_OFFSET,
              NULL, HFILL
            }
        },
        { &hf_mausb_iflag_hdr_format,
            { "Isochronous Header Format", "mausb.iflag.ihf", FT_UINT8, BASE_HEX,
              NULL, MAUSB_IFLAG_HDR_FORMAT << MAUSB_IFLAG_OFFSET, NULL, HFILL
            }
        },
        { &hf_mausb_iflag_asap,
            { "ASAP", "mausb.iflag.asap", FT_BOOLEAN, 8,
              TFS(&tfs_set_notset), MAUSB_IFLAG_ASAP << MAUSB_IFLAG_OFFSET,
              NULL, HFILL
            }
        },

        { &hf_mausb_stream_id,
            { "Stream ID", "mausb.streamid", FT_UINT16, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_seq_num,
            { "Sequence Number", "mausb.seqnum", FT_UINT24, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_req_id,
            { "Request ID", "mausb.reqid", FT_UINT8, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_present_time,
            { "Presentation Time", "mausb.presenttime", FT_UINT32, BASE_DEC,
              NULL, MAUSB_PRESENT_TIME_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_uframe,
            { "Microframe Number", "mausb.uframe", FT_UINT32, BASE_DEC,
              NULL, MAUSB_UFRAME_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_frame,
            { "Frame Number", "mausb.frame", FT_UINT32, BASE_DEC,
              NULL, MAUSB_FRAME_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_num_segs,
            { "Number of Segments", "mausb.numseg", FT_UINT32, BASE_DEC,
              NULL, MAUSB_NUM_SEGS_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_timestamp,
            { "Timestamp", "mausb.timestamp", FT_UINT32, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_delta,
            { "Delta", "mausb.delta", FT_UINT32, BASE_DEC,
              NULL, MAUSB_DELTA_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_nom_interval,
            { "Nominal Bus Interval", "mausb.nomitvl", FT_UINT32, BASE_DEC,
              NULL, MAUSB_INTERVAL_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_mtd,
            { "Media Time/Transmission Delay", "mausb.mtd", FT_UINT32, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_rem_size_credit,
            { "Remaining Size/Credit", "mausb.remsize_credit", FT_UINT32, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        },
    };


    /* Register info for CapReq/Resp specific fields */
    static hf_register_info hf_cap[] = {

        { &hf_mausb_cap_resp_num_ep,
            { "Number of Endpoints", "mausb.cap_resp.num_ep",
              FT_UINT16, BASE_DEC, NULL, 0,
              "the maximum number of endpoints for this device",
              HFILL
            }
        },
        { &hf_mausb_cap_resp_num_dev,
            { "Number of Devices", "mausb.cap_resp.num_dev",
              FT_UINT8, BASE_DEC, NULL, 0,
              "the maximum number of USB devices the MA USB device can manage",
              HFILL
            }
        },
        { &hf_mausb_cap_resp_num_stream,
            { "Number of Streams", "mausb.cap_resp.num_stream",
              FT_UINT8, BASE_DEC, NULL, MAUSB_CAP_RESP_NUM_STREAM_MASK,
              "2 to the power of this value is the max number of streams supported",
              /* TODO: have dissector print the actual number of streams supported */
              HFILL
            }
        },
        { &hf_mausb_cap_resp_dev_type,
            { "Device Type", "mausb.cap_resp.dev_type", FT_UINT8, BASE_HEX,
              VALS(mausb_cap_resp_dev_type), MAUSB_CAP_RESP_DEV_TYPE_MASK,
              NULL, HFILL
            }
        },
        { &hf_mausb_cap_resp_desc_count,
            { "Descriptors Count", "mausb.cap_resp.desc_count",
              FT_UINT8, BASE_DEC,
              NULL, 0, "The total number of MA Device Capabilities descriptors",
              HFILL
            }
        },
        { &hf_mausb_cap_resp_desc_len,
            { "Descriptors Length", "mausb.cap_resp.desc_len",
              FT_UINT24, BASE_DEC,
              NULL, 0, "The total size of MA Device Capabilities descriptors",
              HFILL
            }
        },
        { &hf_mausb_cap_resp_transfer_req,
            { "Number of Outstanding Transfer Requests",
              "mausb.cap_resp.transfer_req",
              FT_UINT16, BASE_DEC, NULL, 0,
              "The maximum number of total outstanding transfer requests", HFILL
            }
        },
        { &hf_mausb_cap_resp_mgmt_req,
            { "Number of Outstanding Management Requests", "mausb.cap_resp.mgmt_req",
              FT_UINT16, BASE_DEC, NULL,
              MAUSB_CAP_RESP_MGMT_REQ_MASK,
              "The maximum number of host initiated outstanding management requests",
              HFILL
            }
        },
        { &hf_mausb_cap_resp_rsvd,
            { "Reserved", "mausb.cap_resp.rsvd", FT_UINT16, BASE_HEX,
              NULL, MAUSB_CAP_RESP_RSVD_MASK, NULL, HFILL
            }
        },

        /* Device Capability Descriptors */
        { &hf_mausb_dev_cap_len,
            { "Length", "mausb.cap_resp.dev_cap.length",
              FT_UINT8, BASE_DEC, NULL,
              0, NULL, HFILL
            }
        },
        { &hf_mausb_dev_cap_type,
            { "Type", "mausb.cap_resp.dev_cap.type",
              FT_UINT8, BASE_DEC, VALS(mausb_dev_cap_string),
              0, NULL, HFILL
            }
        },
        { &hf_mausb_dev_cap_generic,
            { "Type-specific device capability descriptor fields",
              "mausb.cap_resp.dev_cap.generic",
              FT_NONE, 0, NULL, 0, NULL, HFILL
            }
        }
    };


    /* register info for ep_handle_* specific fields */
    static hf_register_info hf_ep_handle[] = {
        { &hf_mausb_mgmt_ep_handle_num,
            { "Number of Endpoint Handles", "mausb.ep_handle_num",
              FT_UINT8, BASE_DEC,
              NULL, MAUSB_MGMT_NUM_EP_DES_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_mgmt_ep_handle_pad,
            { "Padding to a DWORD", "mausb.ep_handle_pad",
              FT_NONE, 0,
              NULL, 0x0, NULL, HFILL
            }
        },
        { &hf_mausb_mgmt_ep_des_num,
            { "Number of Endpoint Descriptors", "mausb.ep_des_num",
              FT_UINT8, BASE_DEC,
              NULL, MAUSB_MGMT_NUM_EP_DES_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_mgmt_ep_des_size,
            { "Size of Endpoint Descriptors", "mausb.ep_des_size",
              FT_UINT16, BASE_DEC,
              NULL, MAUSB_MGMT_SIZE_EP_DES_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_mgmt_ep_des_pad,
            { "Padding to a DWORD", "mausb.ep_des_pad",
              FT_NONE, 0, NULL,
              0x0,
              NULL, HFILL
            }
        },

        { &hf_mausb_ep_handle_req_pad,
            { "Padding to a DWORD", "mausb.ep_handle_req.pad",
              FT_NONE, 0, NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle_resp_dir,
            { "Direction", "mausb.ep_dir", FT_BOOLEAN, 6,
              TFS(&tfs_ep_handle_resp_dir), MAUSB_EP_HANDLE_RESP_DIR_MASK,
              NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle_resp_iso,
            { "Isochronous", "mausb.ep_iso", FT_BOOLEAN, 6,
              TFS(&tfs_yes_no), MAUSB_EP_HANDLE_RESP_ISO_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle_resp_lman,
            { "L-Managed", "mausb.ep_lman", FT_BOOLEAN, 6,
              TFS(&tfs_supported_not_supported), MAUSB_EP_HANDLE_RESP_LMAN_MASK,
              NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle_resp_valid,
            { "Valid", "mausb.ep_valid", FT_BOOLEAN, 6,
              TFS(&tfs_invalid_valid), MAUSB_EP_HANDLE_RESP_VALID_MASK,
              NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle_resp_ccu,
            { "CCU", "mausb.ep_ccu", FT_UINT16, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle_resp_buf_size,
            { "Buffer Size", "mausb.ep_buf_size", FT_UINT32, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle_resp_iso_prog_dly,
            { "Iso Programming Delay", "mausb.ep_iso_prog_dly", FT_UINT16, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_ep_handle_resp_iso_resp_dly,
            { "Iso Response Delay", "mausb.ep_iso_resp_dly", FT_UINT16, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        }


    };

    /* (Cancel/Clear)Transfer(Req/Resp) specific fields */
    static hf_register_info hf_cancel_transfer[] = {
        { &hf_mausb_clear_transfers_info_block,
            { "Clear Transfers Information Block", "mausb.clear_transfers.info", FT_NONE, 0,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_clear_transfers_status_block,
            { "Cancel Transfers Status Block", "mausb.clear_transfers.status_block", FT_NONE, 0,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_cancel_transfer_rsvd,
            { "Reserved", "mausb.cancel_transfer.rsvd", FT_NONE, 0,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_clear_transfers_req_num,
            { "Number of Blocks", "mausb.clear_transfers_req.num", FT_UINT8, BASE_DEC,
              NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_clear_transfers_req_rsvd,
             { "Reserved", "mausb.clear_transfers_req.rsvd", FT_NONE, 0,
               NULL, 0, NULL, HFILL
             }
        },
        { &hf_mausb_clear_transfers_resp_num,
            { "Number of Blocks", "mausb.clear_transfers_resp.num", FT_UINT32, BASE_DEC,
              NULL, MAUSB_CLEAR_TRANSFERS_RESP_NUM_MASK , NULL, HFILL
            }
        },
        { &hf_mausb_clear_transfers_resp_rsvd,
             { "Reserved", "mausb.clear_transfers_resp.rsvd", FT_UINT32, BASE_HEX,
               NULL, ~MAUSB_CLEAR_TRANSFERS_RESP_NUM_MASK, NULL, HFILL
             }
        },
        { &hf_mausb_cancel_transfer_status,
            { "Status", "mausb.cancel_transfer.status", FT_UINT24, BASE_HEX,
              VALS(mausb_cancel_transfer_status_string),
              MAUSB_CANCEL_TRANSFER_STATUS_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_cancel_transfer_rsvd_2,
            { "Reserved", "mausb.cancel_transfer.rsvd_2", FT_UINT24, BASE_HEX,
              NULL, ~MAUSB_CANCEL_TRANSFER_STATUS_MASK, NULL, HFILL
            }
        },
        { &hf_mausb_clear_transfers_status,
            { "Cancellation Status", "mausb.clear_transfers.status", FT_BOOLEAN, 6,
              TFS(&tfs_success_fail), MAUSB_CLEAR_TRANSFERS_STATUS_MASK,
              NULL, HFILL
            }
        },
        { &hf_mausb_clear_transfers_partial,
            { "Partial Delivery", "mausb.clear_transfers.partial", FT_BOOLEAN, 6,
              NULL, MAUSB_CLEAR_TRANSFERS_PARTIAL_MASK,
              NULL, HFILL
            }
       },
       { &hf_mausb_clear_transfers_start_req_id,
           { "Start Request ID", "mausb.clear_transfers.start_reqid", FT_UINT8, BASE_DEC,
             NULL, 0, NULL, HFILL
           }
       },
       { &hf_mausb_clear_transfers_last_req_id,
           { "Last Request ID", "mausb.clear_transfers.last_reqid", FT_UINT8, BASE_DEC,
             NULL, 0, NULL, HFILL
           }
       },
       { &hf_mausb_clear_transfers_req_block_rsvd,
            { "Reserved", "mausb.clear_transfers_req.block_rsvd", FT_NONE, 0,
              NULL, 0, NULL, HFILL
            }
       },
       { &hf_mausb_clear_transfers_resp_block_rsvd,
            { "Reserved", "mausb.clear_transfers_resp.block_rsvd", FT_UINT32, BASE_HEX,
              NULL, MAUSB_CLEAR_TRANSFERS_RESP_BLOCK_RSVD_MASK, NULL, HFILL
            }
       },

       { &hf_mausb_cancel_transfer_seq_num,
            { "Delivered Sequence Number", "mausb.cancel_transfer.seqnum",
              FT_UINT24, BASE_DEC, NULL, 0, NULL, HFILL
            }
        },
        { &hf_mausb_cancel_transfer_byte_offset,
            { "Delivered Byte Offset", "mausb.cancel_transfer.byte_offset",
              FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL
            }
        },
    };

    static hf_register_info oui_hf[] = {
      { &hf_llc_mausb_pid,
        { "PID",    "mausb.pid",  FT_UINT16, BASE_HEX,
          VALS(mausb_pid_string), 0x0, NULL, HFILL }
      }
    };

    /* Setup protocol subtree array */
    static int *ett[] = {
        &ett_mausb,
        &ett_mausb_flags,
        &ett_mausb_ep_handle,
        &ett_mausb_tflags,
        &ett_mausb_iflags,
        &ett_mausb_present_time,
        &ett_mausb_timestamp,
        &ett_mgmt,
        &ett_dev_cap,
        &ett_clear_transfers_block
    };

    static ei_register_info ei[] = {
        { &ei_ep_handle_len,
            { "mausb.ei.ep_handle.length", PI_PROTOCOL, PI_WARN,
              "Invalid Endpoint handle length field", EXPFILL }
        },
        { &ei_len,
            { "mausb.ei.length", PI_MALFORMED, PI_ERROR,
              "Packet length field does not match size of packet", EXPFILL }
        },
        { &ei_mgmt_type_undef,
            { "mausb.ei.type", PI_PROTOCOL, PI_WARN,
              "Undefined management packet type", EXPFILL }
        },
        { &ei_mgmt_type_spec_len_long,
            { "mausb.ei.type_spec.len_long", PI_PROTOCOL, PI_WARN,
              "Data exists after type-specific management packet field", EXPFILL }
        },
        { &ei_mgmt_type_spec_len_short,
            { "mausb.ei.type_spec.len", PI_PROTOCOL, PI_WARN,
              "Expected type-specific management packet data", EXPFILL }
        },
        { &ei_dev_cap_len,
            { "mausb.ei.cap_resp.dev_cap.length", PI_PROTOCOL, PI_WARN,
              "Incorrect length value for this device capability descriptor",
              EXPFILL }
        },
        { &ei_dev_cap_resp_desc_len,
            { "mausb.ei.dev_cap_resp.desc_len", PI_PROTOCOL, PI_WARN,
              "Incorrect value in Device Descriptors Length field", EXPFILL }
        },
        { &ei_cap_resp_desc_len,
            { "mausb.ei.cap_resp.desc_len", PI_PROTOCOL, PI_WARN,
              "Value in Descriptors Length field exceeds actual space in packet", EXPFILL }
        },
    };

    expert_module_t* expert_mausb;

    /* Register the protocol name and description */
    proto_mausb = proto_register_protocol("Media Agnostic USB", "MAUSB", "mausb");

    /* Required function calls to register the header fields and subtrees */
    proto_register_field_array(proto_mausb, hf, array_length(hf));
    proto_register_field_array(proto_mausb, hf_cap, array_length(hf_cap));
    proto_register_field_array(proto_mausb, hf_ep_handle, array_length(hf_ep_handle));
    proto_register_field_array(proto_mausb, hf_cancel_transfer, array_length(hf_cancel_transfer));
    proto_register_subtree_array(ett, array_length(ett));

    /* for Expert info */
    expert_mausb = expert_register_protocol(proto_mausb);
    expert_register_field_array(expert_mausb, ei, array_length(ei));

    llc_add_oui(OUI_WFA, "llc.wfa_pid", "LLC WFA OUI PID", oui_hf, proto_mausb);

    /* Register the dissectors */
    mausb_tcp_handle = register_dissector("mausb", dissect_mausb, proto_mausb);
    mausb_pkt_handle = register_dissector("mausb.pkt", dissect_mausb_pkt, proto_mausb);

}

void
proto_reg_handoff_mausb(void)
{
    dissector_add_uint("llc.wfa_pid", PID_MAUSB, mausb_pkt_handle);

    dissector_add_uint_range_with_preference("tcp.port", "", mausb_tcp_handle);
    dissector_add_for_decode_as_with_preference("udp.port", mausb_pkt_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:
 */

Coverage Report

Created: 2026-08-14 06:45