NDK_FN_SEND callback function (ndkpi.h)

Article
11/12/2021

The NdkSend (NDK_FN_SEND) function posts a send request on an NDK queue pair (QP).

Syntax

NDK_FN_SEND NdkFnSend;

NTSTATUS NdkFnSend(
  [in]           NDK_QP *pNdkQp,
  [in, optional] PVOID RequestContext,
                 const NDK_SGE *pSgl,
  [in]           ULONG nSge,
  [in]           ULONG Flags
)
{...}

Parameters

[in] pNdkQp

A pointer to an NDK queue pair (QP) object (NDK_QP).

[in, optional] RequestContext

A context value to be returned in the RequestContext member of the NDK_RESULT structure for this request.

pSgl

An array of SGE structures (NDK_SGE) that represent the buffers holding the data to send.

[in] nSge

The number of SGE structures in the array that is specified in the pSgl parameter.

[in] Flags

A bitwise OR of flags which specifies the operations that are allowed. The following flags are supported:

Value	Meaning
NDK_OP_FLAG_SILENT_SUCCESS 0x00000001	Indicates the successful completion of this request does not generate a completion event in the outbound completion queue. However, requests that fail do generate an event in the completion queue.
NDK_OP_FLAG_READ_FENCE 0x00000002	Indicates that all prior read requests must be complete before the hardware begins processing this request.
NDK_OP_FLAG_SEND_AND_SOLICIT_EVENT 0x00000004	Indicates that the completion queue for the peer generates a notification. For more information about NDK_OP_FLAG_SEND_AND_SOLICIT_EVENT, see the Remarks section.
NDK_OP_FLAG_INLINE 0x00000040	Indicates that the memory referenced by the SGEs should be transferred inline. Also, the MemoryRegionToken value in the NDK_SGE entries might be invalid. Inline requests do not need to limit the number of entries in the SGE list to the MaxInitiatorRequestSge value that is specified when the queue pair was created. The amount of memory transferred inline must be within the inline data limits of the queue pair.
NDK_OP_FLAG_DEFER 0x00000200	Indicates to the NDK provider that it may defer indicating the request to hardware for processing. For more information about this flag, see NDKPI Deferred Processing Scheme. Note This flag is supported only in NDKPI 1.2 (Windows Server 2012 R2) and later.

Return value

The NdkSend function returns one of the following NTSTATUS codes.

Return code	Description
STATUS_SUCCESS	The send request was posted successfully. A completion entry will be queued to the completion queue (CQ) when the work request is completed.
STATUS_CONNECTION_INVALID	The queue pair (QP) is not connected.
Other status codes	An error occurred.

Remarks

NdkSend posts a send request on a queue pair (QP).

You can use the NDK_OP_FLAG_SEND_AND_SOLICIT_EVENT flag if you issue multiple, related send requests. Set this flag on the last request in the group of related send requests.

An NDK consumer can use this flag when issuing multiple, related send requests. The NDK consumer sets this flag only on the last, related send request. The peer will receive all the send requests as normal. However, when the peer receives the last send request (the request with the NDK_OP_FLAG_SEND_AND_SOLICIT_EVENT flag set), the completion queue for the peer generates a notification. The notification is generated after the receive request completes. This flag has no meaning to the receiver (peer) unless the receiver has previously called the NdkArmCq (NDK_FN_ARM_CQ) function with the notification type set to NDK_CQ_NOTIFY_SOLICITED.

Note Requests that complete with an error always match the NDK_CQ_NOTIFY_SOLICITED notification type.

Requirements

Requirement	Value
Minimum supported client	None supported,Supported in NDIS 6.30 and later.
Minimum supported server	Windows Server 2012
Target Platform	Windows
Header	ndkpi.h (include Ndkpi.h)
IRQL	<=DISPATCH_LEVEL