RttcpipfltTransmitEx

RttcpipfltTransmitEx is called every time the TCP/IP Stack is about to send an Ethernet frame over the network. The filter can pass the frame down to the NIC by returning TRUE or drop the frame by returning FALSE. This function is like RttcpipfltTransmit, but it includes a pointer to the network device that should send the frame.

Note: Since this routine is called for every frame to transmit, it should complete its work as quickly as possible.

Syntax

BOOL RttcpipfltTransmitEx(
  [in]    RTTCPIPFLT_ETHERNET_HEADER *pEthernetHeader,
  [in]    VOID *pData,
  [in]    ULONG ulEthernetDataSize,
  [in]    VOID *ndp
);

Parameters

pEthernetHeader

Pointer to a data structure representing the 14-byte Ethernet header of the frame to be sent.

pData

Pointer to the first byte of Ethernet payload (just after the 14-byte Ethernet header) of the frame to be sent.

ulEthernetDataSize

Size of the Ethernet payload (this does NOT include the 14-byte Ethernet header).

ndp

Network device pointer. This is an opaque pointer that identifies the NIC that should send the Ethernet frame. This pointer can be used as a parameter of various TCP/IP Stack API functions, such as RttcpipGetDeviceName, RttcpipGetIpAddress, etc.

Return Value

If the frame must be passed to the NIC, it returns TRUE. If the frame must be dropped, it returns FALSE.

Remarks

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

• RttcpipfltTransmit or RttcpipfltTransmitEx AND
• RttcpipfltReceive or RttcpipfltReceiveEx

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.

Requirements

See Also:

• RttcpipfltReceive
• RttcpipfltReceiveEx
• RttcpipfltTransmit