EVT_NET_ADAPTER_RECEIVE_SCALING_ENABLE callback function (netreceivescaling.h)

The EvtNetAdapterReceiveScalingEnable callback function is implemented by the client driver to enable receive side scaling (RSS) for a network interface controller (NIC).

Syntax

EVT_NET_ADAPTER_RECEIVE_SCALING_ENABLE EvtNetAdapterReceiveScalingEnable;

NTSTATUS EvtNetAdapterReceiveScalingEnable(
  [_In_] NETADAPTER Adapter,
  [_In_] NET_ADAPTER_RECEIVE_SCALING_HASH_TYPE HashType,
  [_In_] NET_ADAPTER_RECEIVE_SCALING_PROTOCOL_TYPE ProtocolType
)
{...}

Parameters

[_In_] Adapter

The NETADAPTER object the client driver obtained in a previous call to NetAdapterCreate.

[_In_] HashType

A NET_ADAPTER_RECEIVE_SCALING_HASH_TYPE value that specifies the type of receive side scaling (RSS) hash function that a NIC should use to compute the hash values for incoming packets.

[_In_] ProtocolType

A NET_ADAPTER_RECEIVE_SCALING_PROTOCOL_TYPE value that specifies the portion of received network data that an RSS-capable NIC must use to calculate an RSS hash value.

Return value

Returns STATUS_SUCCESS if RSS was successfully enabled. Otherwise, returns an appropriate NTSTATUS error code.

Remarks

Register your implementation of this callback function by setting the appropriate member of the NET_ADAPTER_RECEIVE_SCALING_CAPABILITIES structure and then calling NetAdapterSetReceiveScalingCapabilities. Client drivers typically call NetAdapterSetReceiveScalingCapabilities when starting a net adapter, before calling NetAdapterStart.

Example

In this callback, clients turn RSS on with the supplied information by setting the appropriate control bits in hardware.

NTSTATUS
MyEvtNetAdapterReceiveScalingEnable(
	_In_ NETADAPTER Adapter,
	_In_ NET_ADAPTER_RECEIVE_SCALING_HASH_TYPE HashType,
	_In_ NET_ADAPTER_RECEIVE_SCALING_PROTOCOL_TYPE ProtocolType
)
{
	NTSTATUS status = STATUS_SUCCESS;

	// Not using the hash type in this example
	UNREFERENCED_PARAMETER(HashType);

	UINT32 controlBitsEnable = MY_RSS_MULTI_CPU_ENABLE | MY_RSS_HASH_BITS_ENABLE;

	// Set the appropriate control bits for IPv4
	if(ProtocolType & NetAdapterReceiveScalingProtocolTypeIPv4)
	{
		controlBitsEnable |= MY_RSS_IPV4_ENABLE;

		if (ProtocolType & NetAdapterReceiveScalingProtocolTypeTcp)
        {
            controlBitsEnable |= MY_RSS_IPV4_TCP_ENABLE;
        }
	}

	// Repeat for IPv6
	...

	// Set the bits in hardware
	if(!MyHardwareRssSetControl(controlBitsEnable))
	{
		WdfDeviceSetFailed(Adapter->WdfDevice, WdfDeviceFailedAttemptRestart);
        return STATUS_UNSUCCESSFUL;
	}

	// Perform other tasks like restarting the Rx queue

	return STATUS_SUCCESS;
}

Requirements

See also

EvtNetAdapterReceiveScalingDisable

NetAdapterCx Receive Side Scaling