NDIS_GET_ORIGINAL_PACKET (Windows CE 5.0)
This macro returns a pointer to a packet descriptor that the lowest-level driver in a layered stack of NDIS drivers indicated. The calling driver should access the out-of-band (OOB) data block from this original packet rather than the packet that the driver below the calling driver indicated. If the calling driver is not part of a layered stack, the returned packet descriptor will be identical to the packet that the driver below the calling driver indicated.
PNDIS_PACKET NDIS_GET_ORIGINAL_PACKET(PNDIS_PACKET_P);
Parameters
- _P
Points to a packet descriptor that the driver below the calling driver indicated.
Return Values
The return value is a pointer to the packet descriptor that the lowest-level driver in a layered stack of NDIS drivers indicated, or if the calling driver is not part of a layered stack, the return value is the packet descriptor that the driver below the calling driver indicated.
Remarks
Typically, the packet that is returned by NDIS_GET_ORIGINAL_PACKET is the same packet that was indicated up by the driver below the calling driver. To indicate packets to a higher-level driver, a driver can call, for example, the NdisMIndicateReceivePacket function. To retrieve packets that were indicated up from a lower-level driver, a driver can call the NdisGetReceivedPacket function.
Call NDIS_GET_ORIGINAL_PACKET to obtain a pointer to a packet that was indicated up by the lowest-level driver in a layered stack of NDIS protocol and intermediate drivers. In this call, the drivers passed the pointer to the received packet through the higher-level layered drivers. In this way, each driver in the layered stack can access the OOB data block associated with a packet received from the network, without requiring that the packet be copied to each layer.
The NDIS_GET_ORIGINAL_PACKET macro is defined as follows.
#define NDIS_GET_ORIGINAL_PACKET(_P) NDIS_PER_PACKET_INFO_FROM_PACKET(_P, OriginalPacketInfo)
The following example code retrieves a packet that was received from the driver below and obtains the original packet from the retrieved packet.
// Get the original packet, which could be the received packet
// or the packet originating from the lowest-level driver.
// This result is based on the number of layered drivers in the stack.
//
Pkt = NdisGetReceivedPacket(BindingHandle, MacReceiveContext);
OrigPkt = NDIS_GET_ORIGINAL_PACKET(Pkt);
Requirements
OS Versions: Windows CE .NET 4.0 and later.
Header: Ndis.h.
See Also
NDIS_PACKET | NdisGetReceivedPacket | NdisMIndicateReceivePacket | NDIS_PER_PACKET_INFO_FROM_PACKET | NDIS_PACKET_OOB_DATA | NDIS_GET_PACKET_TIME_RECEIVED | NDIS_SET_ORIGINAL_PACKET | NDIS_GET_PACKET_MEDIA_SPECIFIC_INFO | ProtocolReceive
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