FWPS_CALLOUT_CLASSIFY_FN0 callback function (fwpsk.h)

The filter engine calls a callout's classifyFn0 callout function whenever there is data to be processed by the callout.

Syntax

FWPS_CALLOUT_CLASSIFY_FN0 FwpsCalloutClassifyFn0;

void FwpsCalloutClassifyFn0(
  [in]      const FWPS_INCOMING_VALUES0 *inFixedValues,
  [in]      const FWPS_INCOMING_METADATA_VALUES0 *inMetaValues,
  [in, out] void *layerData,
  [in]      const FWPS_FILTER0 *filter,
  [in]      UINT64 flowContext,
  [in, out] FWPS_CLASSIFY_OUT0 *classifyOut
)
{...}

Parameters

[in] inFixedValues

A pointer to an FWPS_INCOMING_VALUES0 structure. This structure contains the values for each of the data fields at the layer being filtered.

[in] inMetaValues

A pointer to an FWPS_INCOMING_METADATA_VALUES0 structure. This structure contains the values for each of the metadata fields at the layer being filtered.

[in, out] layerData

A pointer to a structure that describes the raw data at the layer being filtered. This parameter might be NULL, depending on the layer being filtered and the conditions under which the classifyFn0 callout function is called. For the stream layer, this parameter points to an FWPS_STREAM_CALLOUT_IO_PACKET0 structure. For all of the other layers, this parameter points to a NET_BUFFER_LIST structure if it is not NULL.

[in] filter

A pointer to an FWPS_FILTER0 structure. This structure describes the filter that specifies the callout for the filter's action.

[in] flowContext

A UINT64-typed variable that contains the context associated with the data flow. If no context is associated with the data flow, then this parameter is zero. If the callout is added to the filter engine at a filtering layer that does not support data flows, the classifyFn0 callout function should ignore this parameter.

[in, out] classifyOut

A pointer to an FWPS_CLASSIFY_OUT0 structure that receives any data that the classifyFn0 callout function returns to the caller.

Return value

None

Remarks

A callout driver registers a callout's callout functions with the filter engine by calling the FwpsCalloutRegister0 function.

The filter engine calls a callout's classifyFn0 callout function with data to be processed whenever all of the test conditions are true for a filter in the filter engine that specifies the callout for the filter's action.

A callout's classifyFn0 callout function should clear the FWPS_RIGHT_ACTION_WRITE flag in the rights member of the FWPS_CLASSIFY_OUT0 structure in any of the following situations:

• When the classifyFn0 callout function sets the actionType member of the FWPS_CLASSIFY_OUT0 structure to FWP_ACTION_BLOCK.
• When the classifyFn0 callout function sets the actionType member of the FWPS_CLASSIFY_OUT0 structure to FWP_ACTION_PERMIT and the FWPS_FILTER_FLAG_CLEAR_ACTION_RIGHT flag is set in the Flags member of the FWPS_FILTER0 structure.
• When a callout has indicated that it intends to modify the clone net buffer list by setting the intendToModify parameter to TRUE in a call to the FwpsReferenceNetBufferList0 function.

Requirements

See also

Associating Context with a Data Flow

Callout Driver Callout Functions

Data Logging

FWPS_CALLOUT0

FWPS_CLASSIFY_OUT0

FWPS_FILTER0

FWPS_INCOMING_VALUES0

FwpsCalloutRegister0

FwpsCalloutRegister1

FwpsReferenceNetBufferList0

NET_BUFFER_LIST

Packet Modification Examples

Registering Callouts with the Filter Engine

Using a Callout for Deep Inspection of Stream Data

Using a Callout for Deep Inspection

classifyFn

classifyFn1

classifyFn2