NDIS_OOB_DATA_FROM_PACKET (Windows CE 5.0)
This macro returns a pointer to the out-of-band (OOB) data block associated with a given packet descriptor.
PNDIS_PACKET_OOB_DATA NDIS_OOB_DATA_FROM_PACKET(PNDIS_PACKET_P);
Parameters
- _P
Points to a packet descriptor.
Return Values
The return value is a pointer to the OOB data block associated with the given packet descriptor. The return value is NULL if there is no OOB information for the packet.
Remarks
Lower-level NDIS drivers that supply out-of-band information with the packet descriptors they allocate for indications can use NDIS_OOB_DATA_FROM_PACKET to gain access to the OOB block associated with a driver-allocated packet descriptor. Such a driver would then set up OOB information before indicating a receive packet.
For example, an NDIS intermediate driver might copy the OOB information from a received packet into a fresh packet descriptor with NdisMoveMemory before forwarding the indication up to bound protocols. In this case, the intermediate driver calls NdisMoveMemory with the pointers returned by NDIS_OOB_DATA_FROM_PACKET as the Source and Destination pointers and sizeof(NDIS_PACKET_OOB_DATA) as the Length.
Lower-level NDIS drivers also might use this macro when the Status of an indicated packet is returned from NdisMIndicateReceivePacket with NDIS_STATUS_SUCCESS or when MiniportReturnPacket is called with a packet descriptor to be reinitialized for reuse. In these circumstances, the driver can call NdisZeroMemory with the pointer returned by NDIS_OOB_DATA_FROM_PACKET and sizeof(NDIS_PACKET_OOB_DATA) to clear the OOB data block associated with the packet descriptor. Alternatively, such a driver can use the appropriate NDIS_SET_PACKET_XXX macros to reinitialize specific members in the OOB data block for subsequent indications with the returned packet descriptor.
Higher-level NDIS drivers can use NDIS_OOB_DATA_FROM_PACKET to reinitialize the OOB data block associated with the packet descriptors they allocate to specify sends when such a packet descriptor has been returned to the ProtocolSendComplete function. Consequently, drivers underlying such a protocol might use NDIS_OOB_DATA_FROM_PACKET to read the OOB information for an incoming send packet.
A driver should never pass a packet descriptor to NdisZeroMemory in an attempt to clear the OOB data block associated with a packet descriptor. Doing this destroys the given packet descriptor, renders it useless for subsequent indications or sends, and causes a memory leak. A driver must pass the pointer returned by NDIS_OOB_DATA_FROM_PACKET to reinitialize the OOB data block associated with a driver-allocated packet descriptor.
The NDIS_OOB_DATA_FROM_PACKET macro is defined as follows.
#define NDIS_OOB_DATA_FROM_PACKET(_p) \
(PNDIS_PACKET_OOB_DATA)((PUCHAR)(_p) + \
(_p)->Private.NdisPacketOobOffset)
Requirements
OS Versions: Windows CE .NET 4.0 and later.
Header: Ndis.h.
See Also
MiniportReturnPacket | NDIS_PACKET_OOB_DATA | NdisAllocatePacket | NdisMIndicateReceivePacket | NdisMoveMemory | NdisZeroMemory | ProtocolSendComplete
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