NDIS_TCP_OFFLOAD_SEND_COMPLETE callback function

Description

[The TCP chimney offload feature is deprecated and should not be used.]

An offload target calls the NdisTcpOffloadSendComplete function to complete one or more send requests that were made to the MiniportTcpOffloadSend function of the offload target.

Parameters

NdisMiniportHandle [in]

The handle that the offload target obtained in a previous call to the NdisMRegisterMiniportDriver function.

NetBufferList [in]

A pointer to a NET_BUFFER_LIST structure. This structure can be a stand-alone structure or the first structure in a linked list of NET_BUFFER_LIST structures. The offload target obtained these structures in one or more calls to its MiniportTcpOffloadSend function.

Remarks

To improve system performance, an offload target can create a linked list that contains NET_BUFFER_LIST structures from multiple calls to the MiniportTcpOffloadSend function. The driver can then pass such a linked list in a single call to the NdisTcpOffloadSendComplete function.

Before completing one or more send requests, the offload target must do the following for each NET_BUFFER_LIST structure that it passes to the NdisTcpOffloadSendComplete function:

• Write a status value to the Status member:

  • NDIS_STATUS_SUCCESS indicates that all data associated with the NET_BUFFER_LIST was successfully sent by the offload target and that the offload target received from the remote host an acknowledgment for all the transmitted data. Note that this differs from the non-offload send function, MiniportSendNetBufferLists, which does not monitor acknowledgments.
  • A status value other than NDIS_STATUS_SUCCESS--for example, a status value of NDIS_STATUS_REQUEST_ABORTED or NDIS_STATUS_UPLOAD_IN_PROGRESS--indicates that the send data was not successfully acknowledged. The offload target might or might not have sent the data. The offload target should fail the send operation for all subsequent NET_BUFFER_LIST structures in the linked list without sending any more data associated with these structures. The offload target writes a status value of NDIS_STATUS_UPLOAD_IN_PROGRESS when the offload of the TCP connection on which the data is to be sent is being terminated. In this case, the host stack queues and processes the TCP data. The offload target writes a status value of NDIS_STATUS_REQUEST_ABORTED if it has received an RST segment on the TCP connection on which the data is to be sent. In this case, the host stack does not process the TCP data.
  • The offload target should complete a partial send for, at most, one NET_BUFFER_LIST structure in linked list. The offload target writes a status value other than NDIS_STATUS_SUCCESS--for example, a status value of NDIS_STATUS_ABORTED or NDIS_STATUS_UPLOAD_IN_PROGRESS--to such a NET_BUFFER_LIST structure.
  • If an intermediate driver cannot allocate memory to propagate the send operation to an underlying offload target, it writes a status value of NDIS_STATUS_REQUEST_UPLOAD to the first NET_BUFFER_LIST structure in the linked list and NDIS_STATUS_UPLOAD_REQUESTED to all subsequent NET_BUFFER_LIST structures in the linked list. The intermediate driver must not propagate the NET_BUFFER_LIST structures to an underlying offload target. The host stack will perform the send operation.

• Specify the number of data bytes sent. The offload target does this by calling the NET_BUFFER_LIST_INFO macro with an id of TcpOffloadBytesTransferred.

• Call the NdisAdvanceNetBufferDataStart function for each NET_BUFFER structure that is associated with the NET_BUFFER_LIST structure. The NetBuffer parameter passed to the NdisAdvanceNetBufferDataStart function should point to the NET_BUFFER structure. The DataOffsetDelta parameter should specify the number of data bytes from the NET_BUFFER structure that were transmitted by the offload target and that were acknowledged by the remote host. The FreeMdl parameter is NULL.

See also

MiniportSendNetBufferLists

MiniportTcpOffloadSend

NET_BUFFER

NET_BUFFER_LIST

NdisAdvanceNetBufferDataStart

NdisMRegisterMiniportDriver