Obtención de la dirección Bluetooth del dispositivo HF

En el tema Obtención de la dirección Bluetooth del dispositivo HF se muestra cómo el controlador de audio puede obtener la dirección Bluetooth de un dispositivo emparejado sin manos (HF).

La cadena de dirección puede ser útil para identificar de forma única un dispositivo HF emparejado determinado. Por ejemplo, la cadena de dirección se puede usar como parámetro ReferenceString que se pasa a IoRegisterDeviceInterface, el parámetro RefString que se pasa a KsCreateFilterFactory o el parámetro Name que se pasa a PcRegisterSubdevice.

Tenga en cuenta que el GUID_DEVINTERFACE_BLUETOOTH_HFP_SCO_HCIBYPASS vínculo simbólico de interfaz de dispositivo también es único para cada dispositivo HF emparejado, pero esta cadena puede ser demasiado larga para algunos fines.

La rutina IoHelperGetDevicePdo que se muestra en el ejemplo de código siguiente es una función de utilidad que usa IoHelperGetDeviceBluetoothAddress. Se puede llamar a estas funciones mientras el controlador de audio controla una notificación de llegada de la interfaz PnP. El controlador de audio obtiene el objeto de dispositivo de IoGetDeviceObjectPointer y lo pasa a IoHelperGetDeviceBluetoothAddress.

_IRQL_requires_(PASSIVE_LEVEL)
NTSTATUS
IoHelperGetDevicePdo(
    _In_ PDEVICE_OBJECT DeviceObject,
    _Out_ PDEVICE_OBJECT *PhysicalDeviceObject
    )

/*++

Routine description:
    Returns a pointer to the physical device object in a driver stack and
    increments the reference count on that object.

Parameters:
    DeviceObject
        Pointer to the device object for which the physical device object is
        retrieved. 

    PhysicalDeviceObject
        Returns a pointer to the physical device object in a stack of device
        objects after incrementing the reference count on the object.

Return value:
    A status code.

Remarks:
    This routine uses IRP_MN_QUERY_DEVICE_RELATIONS TargetDeviceRelation to
    get the physical device object from the device stack.

Requirements:
    IRQL    = PASSIVE_LEVEL

--*/

{
    NTSTATUS status;
    PIRP irp = NULL;
    PDEVICE_RELATIONS deviceRelations = NULL;
    PIO_STACK_LOCATION ioStack;
    KEVENT completionEvent;

    PAGED_CODE();

    irp = IoAllocateIrp(DeviceObject->StackSize, FALSE);
    if (irp == NULL)
    {
        status = STATUS_INSUFFICIENT_RESOURCES;
        goto Exit;
    }

    irp->IoStatus.Status = STATUS_NOT_SUPPORTED;

    ioStack = IoGetNextIrpStackLocation(irp);
    ioStack->MajorFunction = IRP_MJ_PNP;
    ioStack->MinorFunction = IRP_MN_QUERY_DEVICE_RELATIONS;
    ioStack->Parameters.QueryDeviceRelations.Type = TargetDeviceRelation;

    KeInitializeEvent(&completionEvent, SynchronizationEvent, FALSE);

    IoSetCompletionRoutine(irp, OnRequestComplete, &completionEvent, TRUE, TRUE, TRUE);

    status = IoCallDriver(DeviceObject, irp);
    if (status == STATUS_PENDING) {
        // wait for irp to complete
        KeWaitForSingleObject(
            &completionEvent,
            Suspended,
            KernelMode,
            FALSE,
            NULL);
        status = irp->IoStatus.Status;
    }

    if (NT_SUCCESS(status))
    {
        deviceRelations = (PDEVICE_RELATIONS)irp->IoStatus.Information;
        *PhysicalDeviceObject = deviceRelations->Objects[0];
    }

Exit:
    if (deviceRelations != NULL)
    {
        ExFreePool(deviceRelations);
    }
    if (irp != NULL)
    {
        IoFreeIrp(irp);
    }
    return status;
}

_IRQL_requires_(PASSIVE_LEVEL)
NTSTATUS IoHelperGetDeviceBluetoothAddress(
    _In_ PDEVICE_OBJECT DeviceObject,
    _Outptr_ PWSTR *BluetoothAddress,
    _In_ ULONG Tag
    )

/*++

Routine description:
    Returns the Bluetooth address string for the physical device object in the
    device stack.

Parameters:
    DeviceObject
        Pointer to a device object in a device stack whose physical object has
        a Bluetooth address property.

    BluetoothAddress
        Returns a string allocated from NonPagedPoolNx pool. 

    Tag

Return value:
    A status code.

Remarks:
    This routine retrieves the DEVPKEY_Bluetooth_DeviceAddress property from
    the physical device object in the device stack containing the specified
    device object.

Requirements:
    IRQL    = PASSIVE_LEVEL

--*/

{
    NTSTATUS status;
    PDEVICE_OBJECT physicalDeviceObject = NULL;
    PWSTR bluetoothAddress = NULL;
    ULONG requiredSize;
    DEVPROPTYPE devPropType;

    PAGED_CODE();

    status = IoHelperGetDevicePdo(DeviceObject, &physicalDeviceObject);
    if (!NT_SUCCESS(status))
    {
        goto Exit;
    }

    status = IoGetDevicePropertyData(physicalDeviceObject, &DEVPKEY_Bluetooth_DeviceAddress, LOCALE_NEUTRAL, 0, 0, NULL, &requiredSize, &devPropType);
    if (NT_SUCCESS(status) || devPropType != DEVPROP_TYPE_STRING)
    {
        status = STATUS_UNSUCCESSFUL;
        goto Exit;
    }
    if (status != STATUS_BUFFER_TOO_SMALL)
    {
        goto Exit;
    }

    bluetoothAddress = (PWCH)ExAllocatePoolWithTag(NonPagedPoolNx, requiredSize, Tag);
    if (bluetoothAddress == NULL)
    {
        status = STATUS_INSUFFICIENT_RESOURCES;
        goto Exit;
    }

    status = IoGetDevicePropertyData(physicalDeviceObject, &DEVPKEY_Bluetooth_DeviceAddress, LOCALE_NEUTRAL, 0, requiredSize, bluetoothAddress, &requiredSize, &devPropType);
    if (!NT_SUCCESS(status))
    {
        goto Exit;
    }

    *BluetoothAddress = bluetoothAddress;
    bluetoothAddress = NULL;
    status = STATUS_SUCCESS;

Exit:
    if (bluetoothAddress != NULL)
    {
        ExFreePoolWithTag(bluetoothAddress, Tag);
    }
    if (physicalDeviceObject != NULL)
    {
        ObDereferenceObject(physicalDeviceObject);
    }
    return status;
}