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FN_VMB_CHANNEL_SEND_SYNCHRONOUS_REQUEST callback function (vmbuskernelmodeclientlibapi.h)

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The VmbChannelSendSynchronousRequest function sends a packet to the opposite endpoint and waits for a response.

Syntax

FN_VMB_CHANNEL_SEND_SYNCHRONOUS_REQUEST FnVmbChannelSendSynchronousRequest;

NTSTATUS FnVmbChannelSendSynchronousRequest(
  VMBCHANNEL Channel,
  PVOID Buffer,
  UINT32 BufferSize,
  PMDL ExternalDataMdl,
  UINT32 Flags,
  PVOID CompletionBuffer,
  PUINT32 CompletionBufferSize,
  PLARGE_INTEGER Timeout
)
{...}

Parameters

Channel

A handle for the channel.

Buffer

Data to send.

BufferSize

The size, in bytes, of the data to send.

ExternalDataMdl

A Memory Descriptor List (MDL) that describes an additional buffer to send.

Flags

Standard flags.

CompletionBuffer

Buffer in which to store completion packet results.

CompletionBufferSize

The size, in bytes, of the CompletionBuffer value. This value must be rounded up to nearest 8 bytes, or else the function fails. On success, returns the number of bytes written into CompletionBuffer.

Timeout

A timeout in the style of the KeWaitForSingleObject routing. After this time elapses, the packet is cancelled. For a timeout of zero (0), if a packet does not fir in the ring buffer, it is not queued.

Return value

Return code Description
STATUS_SUCCESS
 The functions finished successfully.
STATUS_BUFFER_OVERFLOW
 The packet did not fit in the buffer and was not queued.
STATUS_CANCELLED
 The packet was canceled.
STATUS_DEVICE_REMOVED
 The channel is being shut down.

Remarks

Clients can run this function with any combination of parameters.

The root may only call this if *Timeout == 0 and the VMBUS_CHANNEL_FORMAT_FLAG_WAIT_FOR_COMPLETION flag is not set.

Important

This function is called through the VMBus Kernel Mode Client Library (KMCL) interface, provided by the Vmbkmcl.sys bus driver. This is a client function accessed from the KMCL_CLIENT_INTERFACE_V1 structure.

For more information, see the Remarks section of the KMCL_CLIENT_INTERFACE_V1.

Requirements

Requirement Value
Minimum supported client Windows 10, version 1803
Header vmbuskernelmodeclientlibapi.h

See also

KeWaitForSingleObject