Receive processing with network protocol bypass

摘要

An adapter is provided with intelligence that allows it to separate the header parts of a packet being received from the payload it carries, and in most cases move the payload directly into a destination buffer at the application layer or file system layer. Copies by the intermediate layers of the protocol stack are bypassed, reducing the number of times that the payload of a communication must be copied by the host system. At the network interface, a plurality of packets is received, and the payload of each is bypassed directly into the target destination buffer. The network interface device identifies the packets which are in the sequence of packets carrying payload to be stored in the target buffer by the flow specification carried with such packets. Also, the packets carrying data payload for the file include a sequence number or other identifier by which the network interface is able to determine the offset within the target buffer to which the packet is to be stored.

主权项

1. A method for transferring data on a network from a data source to an end station executing a multi-layer network protocol, including a network layer and at least one higher layer, through a network interface on the end station, comprising:
receiving in the network interface of the end station, from the at least one higher layer, a flow specification comprising an identifier of a protocol suite and an identifier of a block of data to be requested from the data source; prior to receiving a first packet of a plurality of packets, wherein the plurality of packets includes the block of data, responsive to a request for the block of data, allocating a target buffer assigned by a process at a layer higher than the network layer for storing the block of data and notifying the network interface of the allocated target buffer; receiving in the network interface athe first packet which carries a data payload from athe block of data in the data source, and a control field identifying the first packet; and determining in the network interface whether the first packet carries a payload with at least a portion of the block of data based on matching the control field in the network interface whether the packet matches awith the identifier of the block of data in the flow specification, and if so transferring the data payload in the first packet directly to athe target buffer assigned by a process at a layer higher than the network layerbased exclusively on the matching.