RtndTransmitFilter

RtndTransmitFilter is called when an outgoing Ethernet frame is received from the stack. This function will be called once per frame transmitted. The filter can elect to send the frame to the driver and return TRUE or drop the frame by returning FALSE.

NOTE: Since this routine is called at every transmit frame, this routine should complete its work quickly. 1- 2 ms is recommended.

Syntax

BOOL RtndTransmitFilter(
   EthernetHeader *pEthernetHeader,
   void *pData,
   unsigned long ulEthernetDataSize
);

Parameters

pEthernetHeader

Pointer to Ethernet header data that contains the value in EthernetHeader format.

pData

Pointer to a data location in theEthernet frame.

ulEthernetDataSize

Size of the Ethernet data in a frame, not including the size of the Ethernet header.

Return Value

A return value of FALSE indicates the frame is being dropped. TRUE indicates that it is being sent to the driver.

Remarks

A filter driver must implement at least one of the following callbacks in each path:

RtndTransmitFilter or RtndTransmitFilterEx AND
RtndReceiveFilter or RtndReceiveFilterEx

At runtime, if the filter is enabled, the network driver will attempt first to call the -Ex function, if found. Otherwise, it will call the non -Ex function.

Please note that the packet is dropped if any of the above functions return FALSE.

Requirements

Minimum Supported Version	RTX64 2013
Header	RtnApi.h
Library	RtTcpip.lib