A multiple simple regular expression matching architecture and coprocessor for deep packet inspection

Pattern matching and regular expression matching are all the critical components for content inspection based applications. But current regular expression matching algorithms or architecture cannot provide a perfect solution for whole matching problem. In some real network security applications, exact strings are the biggest part of rule set, and the second part is simple regular expressions (dot-star and AND-logic), and the other complex regular expressions only occupy a very small part. So, we propose a new hardware-based multiple simple regular expression matching architecture, called MSRM, for Dot-Star and AND-logic regular expressions. Firstly, software compiler splits simple regular expressions into exact strings and relations. Multi-string-matching module judges whether strings match and outputs the matched ID. Based on these matched information and pre-generated RAM data, MSRM can judge whether dot-star and AND-logic regular expressions are satisfied easily and quickly. Experiments with random test data and ClamAV rule set show that MSRM can achieve a high throughput of 2.1 and 2.8 Gbps using Virtex2 and Virtex4 devices respectively which is much higher than software algorithms.