FWPS_CALLOUT2 structure

The FWPS_CALLOUT2 structure defines the data that is required for a callout driver to register a callout with the filter engine.

Note  FWPS_CALLOUT2 is the specific version of FWPS_CALLOUT used in Windows 8 and later. See WFP Version-Independent Names and Targeting Specific Versions of Windows for more information. For Windows 7, FWPS_CALLOUT1 is available. For Windows Vista, FWPS_CALLOUT0 is available.

Syntax


typedef struct FWPS_CALLOUT2_ {
  GUID                                calloutKey;
  UINT32                              flags;
  FWPS_CALLOUT_CLASSIFY_FN2           classifyFn;
  FWPS_CALLOUT_NOTIFY_FN2             notifyFn;
  FWPS_CALLOUT_FLOW_DELETE_NOTIFY_FN0 flowDeleteFn;
} FWPS_CALLOUT2;

Members

calloutKey

A callout driver-defined GUID that uniquely identifies the callout.

flags

Flags that specify callout-specific parameters. Possible flags are:

ValueMeaning
FWP_CALLOUT_FLAG_CONDITIONAL_ON_FLOW
0x00000001

A callout driver can specify this flag when registering a callout that will be added at a layer that supports data flows. If this flag is specified, the filter engine calls the callout driver's classifyFn2 callout function only if there is a context associated with the data flow. A callout driver associates a context with a data flow by calling the FwpsFlowAssociateContext0 function.

FWP_CALLOUT_FLAG_ALLOW_OFFLOAD
0x00000002

A callout driver specifies this flag to indicate that the callout driver's classifyFn2 callout function is unaffected by offloading network data processing to offload-capable network interface cards (NICs). If this flag is not specified, then offloading of network data processing is disabled for all traffic that is processed by any filters that specify the callout for the filter's action.

FWP_CALLOUT_FLAG_ENABLE_COMMIT_ADD_NOTIFY
0x00000004

A callout driver specifies this flag to indicate that it can receive notifications about objects and filters that are added inside a transaction. The filter engine sends the notification after the transaction is committed.

FWP_CALLOUT_FLAG_ALLOW_MID_STREAM_INSPECTION
0x00000008

A callout driver specifies this flag to indicate that it can perform dynamic stream inspection of data flows at stream level. See Stream Inspection.

FWP_CALLOUT_FLAG_ALLOW_RECLASSIFY
0x00000010

A callout driver specifies this flag to register itself to be called when an existing socket operation is reclassified.

FWP_CALLOUT_FLAG_RESERVED1
0x00000020

Reserved for system use. Callout drivers should ignore this flag.

FWP_CALLOUT_FLAG_ALLOW_RSC
0x00000040

A callout driver specifies this flag to indicate that the callout supports receive segment coalescing (RSC) with large packets of up to 64K. If this flag is not specified, and a callout is registered, then RSC is disabled for all traffic that is processed by any filters that specify the callout for the filter's action.

FWP_CALLOUT_FLAG_ALLOW_L2_BATCH_CLASSIFY
0x00000080

A callout driver specifies this flag when registering a callout that will be added at layer 2, to indicate that its classifyFn2 callout function can classify multiple chained NET_BUFFER_LIST structures. See Using Layer 2 Filtering.

 

classifyFn

A pointer to the callout driver's classifyFn2 callout function. The filter engine calls this function whenever there is network data to be processed by the callout.

notifyFn

A pointer to the callout driver's notifyFn2 function. The filter engine calls this function to notify the callout driver about events that are associated with the callout.

flowDeleteFn

A pointer to the callout driver's flowDeleteFn callout function. The filter engine calls this function whenever a data flow that is being processed by the callout is terminated.

If a callout driver does not associate a context with the data flows that the callout processes, then this member should be set to NULL.

Remarks

A callout driver passes a pointer to an initialized FWPS_CALLOUT2 structure to the FwpsCalloutRegister2 function when it registers a callout with the filter engine.

A callout can set the FWP_CALLOUT_FLAG_CONDITIONAL_ON_FLOW flag only for connections on which the driver is interested in performing stream inspections. This callout will be ignored on all other connections. Performance will be improved and the driver will not have to maintain unnecessary state data.

This structure is essentially identical to the previous version, FWPS_CALLOUT1. The only difference is that the members of this version store the updated versions of the callout function pointers.

Requirements

Version

Available starting with Windows 8.

Header

Fwpsk.h (include Fwpsk.h)

See also

classifyFn2
flowDeleteFn
FWPS_CALLOUT0
FWPS_CALLOUT1
FwpsCalloutRegister2
notifyFn2
Using Layer 2 Filtering

 

 

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