Patent ID: 9491069
Filing Date: 2016-11-08
CPC Classification: H04L

Claim Text:
1. A method of screening data packets for matching rules by a packet filter comprising a processing unit, the method performed by the packet filter comprising: receiving data packets, by the packet filter; generating for each received packet, one or more first lookup keys from one or more fields of the packet; accessing a data structure comprising a hash table using the one or more first lookup keys, wherein the hash table comprises an array of pointers, wherein entries in the array of pointers include a four byte pointer field which either has a null value indicating there are no corresponding rules or includes a pointer to a linked list, wherein the pointer comprises a data unit which indicates a memory location having absolute address values and relative offsets, wherein the linked list includes one or more records of the hash table which each include (a) a corresponding key value for verification that the packet matches the record, and (b) further handling instructions, wherein the further handling instructions includes a pointer to a rule record generated by a rule database, wherein the rule record includes a test that needs to be applied to the packet to determine whether the packet matches a rule, wherein at least some of the records in the hash table indicate a second one or more lookup keys to be used in one or more additional accesses to the data structure; performing the further handling instructions to determine whether the packet matches the rule; and upon the packet matching a rule, applying the matching rule to the matching packets.