NdisMIndicateReceivePacket

NdisMIndicateReceivePacket

VOID
NdisMIndicateReceivePacket(
IN NDIS_HANDLE MiniportAdapterHandle,
IN PPNDIS_PACKET ReceivePackets,
IN UINT NumberOfPackets
);

NdisMIndicateReceivePacket notifies NDIS that an array of received packets is available to be forwarded to the appropriate bound protocol driver(s).

Parameters

MiniportAdapterHandle

Specifies the handle originally input to MiniportInitialize.

ReceivePackets

Points to an array of packet descriptor pointers, with each descriptor set up by the caller to specify the received data.

NumberOfPackets

Specifies how many pointers are in the array at ReceivePackets. The value must be at least one.

Comments

Drivers of busmaster DMA NICs are most likely to show significant gains in performance by making multipacket receive indications with NdisMIndicateReceivePacket. However, drivers that indicate out-of-band data with receive packets, such as packet priority and/or timestamps, also can call this function with a single packet at a time.

When a miniport calls NdisMIndicateReceivePacket, NDIS passes each pointer at ReceivePackets separately, in the miniport-determined order, to the ProtocolReceivePacket function(s) of bound protocol(s) that export this function. To other bound protocols, NDIS passes each packet pointer to the ProtocolReceive function(s).

If the miniport did not designate its NIC's medium as a type for which the system supplies a filter package in response to the OID_GEN_MEDIA_IN_USE query, NDIS forwards that driver's receive indications to all bound protocol drivers that export a ProtocolReceivePackets function. Otherwise, NDIS automatically applies the appropriate filter library to the miniport's receive indications.

Any caller of NdisMIndicateReceivePacket must first set up the packet array, as follows:

·Each element is the pointer to a packet descriptor, which the caller must allocate from packet pool. Each packet descriptor can have at most 16 bytes in its ProtocolReserved section.

·All buffer descriptors chained to such a packet descriptor must be allocated from buffer pool. The miniport must call NdisAdjustBufferLength with any buffer descriptor mapping a receive buffer on the NIC that contains less received data than the full range of the receive buffer so that the buffer descriptor will map only the received data for the indication. (The NIC driver must readjust the mapping with NdisAdjustBufferLength when it regains ownership of such a buffer descriptor, as well.)

·If the miniport indicates timestamps for received packets, it must set the TimeReceived and/or TimeSent members in the NDIS_PACKET_OOB_DATA associated with the packet descriptor using the NDIS_SET_PACKET_TIME_RECEIVED and/or NDIS_SET_PACKET_TIME_SENT macros. It can call NdisGetCurrentSystemTime once to set the receive timestamp for all packets of a particular packet array.

·The HeaderSize in the out-of-band data block must match the header size of each received packet for the medium. For example, a driver that selects Ethernet as its preferred medium at initialization would initialize the NDIS_PACKET_OOB_DATA block HeaderSize to 14 when it allocated the packet descriptor.

·If the driver indicates additional out-of-band information with receives, it must set the SizeMediaSpecificInfo to the number of bytes of information supplied in the caller-allocated buffer at MediaSpecificInformation. The miniport can use the NDIS_SET_PACKET_MEDIA_SPECIFIC_INFO macro to set these values. Otherwise, SizeMediaSpecificInfo should be zero, and MediaSpecificInformation should be NULL.

·The miniport can set the Status member of the out-of-band data block to NDIS_STATUS_RESOURCES if it needs to retain ownership of the packet descriptor and buffer descriptors of some element(s) in a particular indication. Setting this status for a packet implicitly sets the same status for all subsequent packets of the indicated array.

Setting NDIS_STATUS_RESOURCES forces NDIS to indicate each such packet, one at a time, to bound protocols' ProtocolReceive functions, thereby forcing each protocol to copy the packet data and release each packet to be returned back to the miniport. Otherwise, the call to NdisMIndicateReceivePacket gives interested protocols exclusive, read-only access to the buffers chained to each packet until either of the following occurs:

·The Status in the out-of-band data block is set to NDIS_STATUS_SUCCESS on return from NdisMIndicateReceivePacket. In this case, the miniport regains ownership of the packet descriptor and all buffers chained to the packet. It can prepare these descriptors immediately for reuse in subsequent receive indications.

·The Status is set to NDIS_STATUS_PENDING on return from NdisMIndicateReceivePacket. In this case, the driver's MiniportReturnPacket function will be called when the miniport regains ownership of the packet and buffer descriptors. It can then prepare these descriptors for reuse in subsequent receive indications.

The miniport should use NDIS_GET_PACKET_STATUS to determine whether it has regained ownership of indicated packets when NdisMIndicateReceivePackets returns control.

When the miniport regains ownership of an indicated packet descriptor, it can prepare the associated out-of-band data block for reuse by passing the pointer returned by NDIS_OOB_DATA_FROM_PACKET to NdisZeroMemory. As an alternative, the miniport can simply reset the relevant member(s) at the subsequent receive with the NDIS_SET_PACKET_XXX macro(s) or with the pointer returned by NDIS_OOB_DATA_FROM_PACKET.

A miniport must not pass a packet descriptor pointer to NdisZeroMemory. Doing this destroys the packet descriptor, rendering it unusable for subsequent indications. To clear the associated out-of-band data block, the driver must pass the pointer returned by NDIS_OOB_DATA_FROM_PACKET.

Packet arrays passed to NdisMIndicateReceivePacket can be allocated on the stack, which cannot be paged out in the NDIS library's receive-indication code path.

When NDIS calls the ProtocolReceive function of a driver that exports a ProtocolReceivePacket function, ProtocolReceive can call NdisQueryReceiveInformation to retrieve the out-of-band information associated with an incoming packet that was indicated as part of a packet array.

Any miniport that calls NdisMIndicateReceivePacket must indicate full packets. Consequently, such a driver has no MiniportTransferData function.

Callers of NdisMIndicateReceivePacket can run at IRQL <= DISPATCH_LEVEL, but usually callers are running at DISPATCH_LEVEL.