NdisGetFirstBufferFromPacketSafe

  • Article

NdisGetFirstBufferFromPacketSafe returns pointers to the buffer descriptor and base virtual address for the first buffer chained to a given packet descriptor, along with the sizes of the first buffer and the total buffer.

VOID  NdisGetFirstBufferFromPacketSafe(
  PNDIS_PACKET Packet,
  PNDIS_BUFFER* FirstBuffer,
  PVOID* FirstBufferVA,
  PUINT FirstBufferLength,
  PUINT TotalBufferLength,
  MM_PAGE_PRIORITY Priority
);

Parameters

  • Packet
    [in] Pointer to the packet descriptor from which this macro extracts information about the initial buffer.
  • FirstBuffer
    [out] Pointer to a caller-supplied variable in which this macro returns the address of the initial buffer descriptor chained to the given packet descriptor.
  • FirstBufferVA
    [out] Pointer to a caller-supplied variable in which this macro returns the base virtual address of the initial buffer associated with the packet. If NdisGetFirstBufferFromPacketSafe fails, it sets FirstBufferVA to NULL.
  • FirstBufferLength
    [out] Pointer to a caller-supplied variable in which this macro returns the number of bytes mapped by the initial buffer descriptor chained to the packet descriptor.
  • TotalBufferLength
    [out] Pointer to a caller-supplied variable in which this macro returns the total number of bytes mapped by all buffer descriptors chained to the packet descriptor.
  • Priority
    [in] Indicates the priority of the request as one of the following:

    • LowPagePriority

      Specifies a low priority. It is acceptable for NdisGetFirstBufferFromPacketSafe to fail if system resources are low.

    • NormalPagePriority

      Specifies a normal priority. It is acceptable for NdisGetFirstBufferFromPacketSafe to fail if system resources are low.

    • HighPagePriority

      Specifies a high priority. It is unacceptable for NdisGetFirstBufferFromPacketSafe to fail unless system resources are exhausted.

Return Values

None.

Remarks

NdisGetFirstBufferFromPacketSafe is the safe version of NdisGetFirstBufferFromPacket. Unlike NdisGetFirstBufferFromPacket, NdisGetFirstBufferFromPacketSafe does not cause a bug check if system resources are low or exhausted. Drivers should call NdisGetFirstBufferFromPacketSafe instead of NdisGetFirstBufferFromPacket. NDIS 5.1 drivers must call NdisGetFirstBufferFromPacketSafe instead of NdisGetFirstBufferFromPacket.

Drivers call NdisGetFirstBufferFromPacketSafe to get information about the initial buffer and amount of data associated with a given packet faster than they can by making calls to NdisQueryPacket and, then, NdisQueryBuffer(Safe).

Requirements

OS Versions: Windows CE .NET 4.0 and later.
Header: Ndis.h.

See Also

MiniportSend | MiniportSendPackets | NdisGetFirstBufferFromPacket | NdisGetNextBuffer | NDIS_PACKET | NdisQueryBuffer | NdisQueryBufferSafe | NdisQueryPacket | ProtocolReceivePacket

 Last updated on Tuesday, May 18, 2004

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