FwpsQueryPacketInjectionState0 (Compact 7)

3/12/2014

This function queries the injection state of packet data.

Syntax

FWPS_PACKET_INJECTION_STATE NTAPI
  FwpsQueryPacketInjectionState0(
    IN HANDLE  injectionHandle,
    IN const NET_BUFFER_LIST  *netBufferList,
    OUT OPTIONAL HANDLE  *injectionContext
    );

Parameters

• injectionHandle
  An injection handle that was previously created by a call to the FwpsInjectionHandleCreate0 function

• netBufferList
  A pointer to a NET_BUFFER_LIST structure that describes the packet data that is being classified. The packet can originate from the network stack or be injected into the network stack by a WFP callout driver

• injectionContext
  An optional handle to the injection context. If it is specified, it can be obtained by calling the FwpsQueryPacketInjectionState0 function when the packet injection state FWPS_PACKET_INJECTION_STATE is FWPS_PACKET_INJECTED_BY_SELF or FWPS_PACKET_PREVIOUSLY_INJECTED_BY_SELF

Return Value

The FwpsQueryPacketInjectionState0 function returns a constant value from the FWPS_PACKET_INJECTION_STATE enumeration.

Remarks

Because injected packet data can be reclassified against the callout that injected it, this function allows a callout to inspect the injection history of packet data and thereby avoid repetitive inspections of packet data.

A callout can track other callout-specific information by using the optional injectionContext handle in a packet injection function during packet data injection. If the FwpsQueryPacketInjectionState0 function returns FWPS_PACKET_INJECTED_BY_SELF or FWPS_PACKET_PREVIOUSLY_INJECTED_BY_SELF, the supplied injectionContext is returned as the completionContext parameter of the function that performed the injection.

If the return value is FWPS_PACKET_INJECTED_BY_SELF or FWPS_PACKET_PREVIOUSLY_INJECTED_BY_SELF, the NET_BUFFER_LIST pointed to by netBufferList should not be additionally modified or pended as part of a cloning and injection procedure. In this case, the callout should set the actionType member of the FWPS_CLASSIFY_OUT0 structure pointed to by the classifyOut parameter of the classifyFn function to one of the following values:

• FWP_ACTION_BLOCK
  Specifies that subsequent modification of the clone net buffer list is not allowed
• FWP_ACTION_PERMIT
  Specifies that the injection function has not modified the clone net buffer list or modification is allowed

Requirements

See Also

Reference

Functions Called by Callout Drivers
NET_BUFFER_LIST
FWPS_CLASSIFY_OUT0
FWPS_PACKET_INJECTION_STATE
classifyFn
FwpsInjectionHandleCreate0
WFP Callout Driver Functions