BffDeviceWdmGetAttachedDevice

Description

Retrieve the next lower WDM device object in the device stack of the specified WDF object. Never call this function in EvtDestroyCallback of BffDevice.

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Declaration

PDEVICE_OBJECT BffDeviceWdmGetAttachedDevice(BFFDEVICE BffDevice);

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Parameter

BffDevice

The WDF object as a bus filter device object.

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Return value

The next lower WDM device object for success; NULL otherwise.

BffDeviceWdmGetDeviceObject

Description

Retrieve the WDM bus filter device object that is associated with the specified WDF object. Never call this function in EvtDestroyCallback of BffDevice.

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Declaration

PDEVICE_OBJECT BffDeviceWdmGetDeviceObject(BFFDEVICE BffDevice);

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Parameter

BffDevice

The WDF object as a bus filter device object.

Return value

The WDM bus filter device object for success; NULL otherwise.

BffPreprocessQueryBusRelations

Description

The callback function for an upper filter driver to preprocess IRP_MN_QUERY_DEVICE_RELATIONS/BusRelations before KMDF. This routine can be passed as EvtDeviceWdmIrpPreprocess into WdfDeviceInitAssignWdmIrpPreprocessCallback for IRP_MJ_PNP/IRP_MN_QUERY_DEVICE_RELATIONS, or be invoked in an upper filter driver's EvtDeviceWdmIrpPreprocess callback function. In the latter case, the upper filter driver must return the value that this routine returns.

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Declaration

NTSTATUS BffPreprocessQueryBusRelations(WDFDEVICE Device, PIRP Irp);

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Parameters

Device	The WDF device object representing an upper filter device object.
Irp	The IRP_MN_QUERY_DEVICE_RELATIONS I/O request packet.

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Return value

The value that WdfDeviceWdmDispatchPreprocessedIrp returns.

BffAllocateContext

Description

Allocate context space for an upper filter device object on behalf of Bus Filter Framework. This routine is typically called in the EvtDriverDeviceAdd callback function.

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Declaration

NTSTATUS BffAllocateContext(WDFDEVICE Device);

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Parameters

Device

The WDF device object representing an upper filter device object.

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Return value

The value that WdfObjectAllocateContext returns.

BffInitialize

Description

Initialize Bus Filter Framework with the initialization data. This routine must be invoked in DriverEntry after a call to WdfDriverCreate.

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Declaration

NTSTATUS BffInitialize(PDRIVER_OBJECT DriverObject,
                       PUNICODE_STRING RegistryPath,
                       PBFF_INITIALIZATION_DATA InitData,
                       WDFDRIVER Driver);

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Parameters

DriverObject	The same as DriverEntry's first parameter.
RegistryPath	The same as DriverEntry's second parameter.
InitData	The initialization data previously prepared by a call to BffSetInitializationData.
Driver	The WDF driver object.

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Return value

One of the following values:

1. Zero or any positive value for success;
2. STATUS_NOT_SUPPORTED if the driver has not called WdfDriverCreate, or if this routine is called for a second time;
3. STATUS_INVALID_PARAMEER if an invalid parameter is specified; or
4. Any other negative value for failure.

BffSetInitializationData

Description

Prepare the initialization data for BFF. Obviously, this routine must be called before BffInitialize. After this call, InitData->PnPMinorFunction[IRP_MN_*] will be NULL-initialized. You may selectively re-initialize InitData->PnPMinorFunction[IRP_MN_*] with your own handlers before calling BffInitialize.

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Declaration

VOID BffSetInitializationData(PBFF_INITIALIZATION_DATA InitData,
        DEVICE_TYPE Type, ULONG Characteristics,
        PBFF_DEVICE_ADD DeviceAdd, PBFF_DEVICE_REMOVE DeviceRemove);

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Parameters

InitData	The pointer to the initialization data, typically declared as a local variable.
Type	The device type for creation of a bus filter device object.
Characteristics	The device characteristics for creation of a bus filter device object.
DeviceAdd	The callback function for creation of a bus filter device object.
DeviceRemove	The callback function for removal of a bus filter device object.

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Return value

None.

BFF_INITIALIZATION_DATA / PBFF_INITIALIZATION_DATA

Desciprtion

Data structure for initialization of Bus Filter Framework. Typically, you declare a local variable of this type, and call BffSetInitializationData to initialize it. Then, you selectively re-initialize PnPMinorFunction[IRP_MN_*] with your own handlers before calling BffInitialize.

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Declaration

typedef struct _BFF_INITIALIZATION_DATA {
 ULONG Size;
 BFF_DEVICE_CONFIG DeviceConfig;
 PBFF_DISPATCH_PNP PnPMinorFunction[IRP_MN_DEVICE_ENUMERATED+1];
} BFF_INITIALIZATION_DATA, *PBFF_INITIALIZATION_DATA;

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Members

Size	Must be the size of this data structure. (Mandatory)
DeviceConfig	Configuration data for a bus filter device object.
PnPMinorFunction	The array of function pointers to PnP minor function handlers.