Lifm algorithm for security association database lookup in IPSEC application

摘要

Current applications used in security system for encryption/decryption/authentication require intense CPU computation for an SAD search. Therefore, a part of the SAD is planted into an ASIC in order to lessen the load of the CPU. The invention provides a high-performance lookup method that is "LIFM" adapted to the ASIC. Initially, the ASIC makes a perfect match by comparing the SAD_index field of all items allocated in the ASIC with an incoming packet to fetch the required SAD_key. If there is no match, the software and hardware are started by issuing an interrupt from the ASIC until the CPU finds a perfectly matched item. Then, the software level updates the perfectly matched item in the ASIC.