Accessing OOB Information

When a received network packet is indicated to ProtocolReceive, it forces the driver to copy the received data into a protocol-supplied buffer. If such an indication has associated media-specific or time stamp information in the OOB block associated with the packet descriptor, a protocol driver can call NdisGetReceivedPacket and NDIS_GET_ORIGINAL_PACKET to copy the media-specific information, as well as any TimeSent and TimeReceived time stamps.

If a received packet is passed to ProtocolReceivePacket, the protocol driver can copy the information from the associated OOB block using NDIS-supplied macros. The following list shows the NDIS-supplied macros used to copy OOB information:

• NDIS_GET_PACKET_MEDIA_SPECIFIC_INFO copies media-specific information.
• NDIS_GET_PACKET_TIME_SENT copies TimeSent.
• NDIS_GET_PACKET_TIME_RECEIVED copies TimeReceived.

TimeSent is the time a packet was sent by the NIC driver on the remote node, and is retrieved and stored by the underlying NIC driver on the local node, if available. TimeReceived is the time that the incoming packet was received on the underlying NIC on the local node.

The current system time can be determined using NdisGetCurrentSystemTime if the protocol converts these time stamps into another format.

See Also

Receiving Data in a Protocol Driver | NdisGetCurrentSystemTime | NDIS_GET_PACKET_MEDIA_SPECIFIC_INFO | NDIS_GET_PACKET_TIME_SENT | NDIS_GET_PACKET_TIME_RECEIVED | ProtocolReceivePacket | NdisGetReceivedPacket | NDIS_GET_ORIGINAL_PACKET | ProtocolReceive

 Last updated on Tuesday, May 18, 2004

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