FILTER_OID_REQUEST callback function

NDIS calls a filter driver's FilterOidRequest function to process an OID request that is associated with the specified filter module.

Note  You must declare the function by using the FILTER_OID_REQUEST type. For more information, see the following Examples section.



NDIS_STATUS FilterOidRequest(
  _In_ NDIS_HANDLE       FilterModuleContext,
{ ... }


FilterModuleContext [in]

A handle to the context area for the filter module that is the target of this request. The filter driver created and initialized this context area in the FilterAttach function.

OidRequest [in]

A pointer to an NDIS_OID_REQUEST structure that specifies the operation requested including the OID_XXX code. The structure can specify either an OID query request or an OID set request. For more information about OIDs, see NDIS OIDs.

Return value

FilterOidRequest returns one of the following status values:

Return codeDescription

FilterOidRequest successfully completed the filter driver's query or set operation for this filter module.


Indicates that the filter driver will complete the request asynchronously. After the driver completes the request, it must call the NdisFOidRequestComplete function to inform NDIS that the request is complete.


Indicates that the request, specified at OidRequest, is invalid or not recognized.


FilterOidRequest does not support the OID, the OID is optional.


Indicates that the buffer, supplied at OidRequest, is too small to hold the requested data.


For a query operation, the InformationBufferLength member of the NDIS_OID_REQUEST structure does not match the length required by the given OID. FilterOidRequest returned the required buffer size, in bytes, in the BytesNeeded member of the NDIS_OID_REQUEST structure.


For a set operation, the data supplied in the InformationBuffer member of the NDIS_OID_REQUEST structure was invalid for the given OID.


FilterOidRequest attempted to gather the requested information but was unsuccessful.


FilterOidRequest failed due to insufficient resources.


FilterOidRequest returns NDIS_STATUS_FAILURE if none of the preceding values applies. The filter driver should call the NdisWriteErrorLogEntry function with parameters that specify the reason for the failure.



FilterOidRequest is an optional function. If a filter driver does not use OID requests, it can set the entry point for this function to NULL when it calls the NdisFRegisterFilterDriver function. If a filter driver defines a FilterOidRequestComplete function, it must provide the FilterOidRequest function.

NDIS calls the filter driver's FilterOidRequest function to process OID requests that are originated by overlying drivers. Filter drivers can forward such requests to underlying drivers by calling the NdisFOidRequest function.

Before the driver calls NdisFOidRequest, the driver must allocate an NDIS_OID_REQUEST structure and transfer the request information to the new structure by calling NdisAllocateCloneOidRequest. As an option, a filter driver can complete a request immediately without forwarding the request.

To complete a request synchronously, the filter driver returns NDIS_STATUS_SUCCESS or a failure status. If the driver returns NDIS_STATUS_PENDING, it must call the NdisFOidRequestComplete function to inform NDIS that the request is complete.

For a query operation, FilterOidRequest returns the requested information in the InformationBuffer member and sets the variable in the BytesWritten member of the NDIS_OID_REQUEST structure to the amount of information it returned. The underlying drivers do this if the filter driver passed the request on with NdisFOidRequest.

For a set operation, FilterOidRequest can use the data in the InformationBuffer member of the NDIS_OID_REQUEST structure to set the information required by the given OID. In this case, FilterOidRequest sets the variable at BytesRead to the amount of the supplied data that it used. The underlying drivers do this if the filter driver passed the request on with NdisFOidRequest.

Like miniport drivers, filter drivers can receive only one request at a time. NDIS serializes requests that it sends to a filter driver. NDIS cannot call FilterOidRequest before a filter driver completes the current request.

NDIS calls FilterOidRequest at IRQL <= DISPATCH_LEVEL.


To define a FilterOidRequest function, you must first provide a function declaration that identifies the type of function you're defining. Windows provides a set of function types for drivers. Declaring a function using the function types helps Code Analysis for Drivers, Static Driver Verifier (SDV), and other verification tools find errors, and it's a requirement for writing drivers for the Windows operating system.

For example, to define a FilterOidRequest function that is named "MyOidRequest", use the FILTER_OID_REQUEST type as shown in this code example:


Then, implement your function as follows:

    NDIS_HANDLE  FilterModuleContext,

The FILTER_OID_REQUEST function type is defined in the Ndis.h header file. To more accurately identify errors when you run the code analysis tools, be sure to add the _Use_decl_annotations_ annotation to your function definition. The _Use_decl_annotations_ annotation ensures that the annotations that are applied to the FILTER_OID_REQUEST function type in the header file are used. For more information about the requirements for function declarations, see Declaring Functions by Using Function Role Types for NDIS Drivers. For information about _Use_decl_annotations_, see Annotating Function Behavior.



Supported in NDIS 6.0 and later.


Ndis.h (include Ndis.h)



See also




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