System for parsing a packet for conformity with a predetermined protocol using mask and comparison values included in a parsing instruction

Abstract

A high performance network interface receives network traffic in the form of packets. The network interface parses one or more headers of a received packet in order to determine whether the packet has been formatted with a pre-selected protocol. If so, one or more efficient enhancements in the processing of a packet may be enabled for the packet. During parsing, header data that may be useful in the processing enhancements may be saved. A packet conforming to one or more of a set of pre-selected protocols may be more completely parsed than a packet not conforming to any of the pre-selected protocols. Instructions for parsing a packet to determine a protocol and to extract useful data are stored in a writeable random-access memory. The instructions may be replaced, modified or supplemented depending upon the composition of network traffic and the protocols selected for enhanced processing. In a parsing instruction executed by a micro-sequencer, a value is extracted from a header and compared to a test value that may be derived from a protocol specification. If the comparison succeeds parsing continues along a first branch; if the comparison succeeds it continues along a second branch. The value extracted from the header may be saved. An offset to a parsing position within the packet is maintained and updated as the packet is parsed. Values other than those extracted for comparison may also be identified and saved.