NdisCopyFromNetBufferToNetBuffer (Compact 7)

3/12/2014

Call this function to copy data from a source NET_BUFFER structure to a destination NET_BUFFER structure.

Syntax

NDIS_STATUS
  NdisCopyFromNetBufferToNetBuffer(
    IN PNET_BUFFER  Destination,
    IN ULONG  DestinationOffset,
    IN ULONG  BytesToCopy,
    IN PNET_BUFFER  Source,
    IN ULONG  SourceOffset,
    OUT PULONG  BytesCopied
    );

Parameters

• Destination
  A pointer to a previously allocated destination NET_BUFFER structure.

• DestinationOffset
  The byte offset within the destination NET_BUFFER structure at which to begin writing the copied data. For more information about DestinationOffset, see the following Comments section.

• BytesToCopy
  The number of bytes to copy.

• Source
  A pointer to a previously allocated source NET_BUFFER structure.

• SourceOffset
  The byte offset within the source NET_BUFFER structure at which to begin to copy the data. For more information about SourceOffset, see the following Comments section.

• BytesCopied
  A pointer to the caller-supplied variable in which this function returns the number of bytes actually copied. This number can be less than the value of BytesToCopy if the source runs out of data or the destination runs out of space.

Return Value

NdisCopyFromNetBufferToNetBuffer returns one of the following status values:

Remarks

The caller of NdisCopyFromNetBufferToNetBuffer allocates the destination NET_BUFFER structure and possibly the source NET_BUFFER structure also. The MDLs of the destination NET_BUFFER structure should have sufficient space to receive the data.

If the source NET_BUFFER structure runs out of data or the destination NET_BUFFER structure runs out of space before the specified number of bytes has been copied, the copy operation stops. In either case, NdisCopyFromNetBufferToNetBuffer returns the number of bytes successfully copied from the source to the destination NET_BUFFER structure.

The caller must make sure that CurrentMdlOffset and CurrentMdl values are correct in the source and destination NET_BUFFER structures. NDIS does not change the members in the destination NET_BUFFER. The caller must update the DataLength, DataOffset, and CurrentMdlOffset values in the destination NET_BUFFER after NdisCopyFromNetBufferToNetBuffer returns.

NDIS uses the offsets in the DestionationOffset and SourceOffset parameters of NdisCopyFromNetBufferToNetBuffer as offsets from the current data offset. For example, if the CurrentMdlOffset value in the destination NET_BUFFER is x, and DestinationOffset value is y, NDIS copies the data to the destination NET_BUFFER at an x + y offset in the memory that the CurrentMdl value describes. Similar rules apply to the CurrentMdlOffset in the source NET_BUFFER and the SourceOffset value.

Requirements

See Also

Reference

NDIS NET_BUFFER Functions
NET_BUFFER