US 7,539,032 B2
Regular expression searching of packet contents using dedicated search circuits
Michael E. Ichiriu, Sunnyvale, Calif. (US); Martin Fabry, Mountain View, Calif. (US); Larry A. Wall, Mountain View, Calif. (US); and Sanjay Sreenath, San Jose, Calif. (US)
Assigned to NetLogic Microsystems, Inc., Mountain View, Calif. (US)
Filed on Sep. 19, 2006, as Appl. No. 11/524,351.
Prior Publication US 2008/0071765 A1, Mar. 20, 2008
Int. Cl. G11C 15/00 (2006.01)
U.S. Cl. 365—49.17  [365/49.1; 711/108] 51 Claims
OG exemplary drawing
 
1. A content search system for determining whether an input string matches any number of regular expressions each including a number of exact patterns and an inexact pattern, the content search system comprising:
a first search circuit dedicated to perform an exact string match operation to determine whether the input string contains a first portion that matches the exact patterns, wherein the first search circuit comprises a state machine implemented by a ternary content addressable memory (TCAM);
a second search circuit dedicated to perform an inexact string match operation to determine whether the input string contains a second portion that matches the inexact pattern, wherein the second search circuit is selectable to execute a microprogram embodying the inexact pattern; and
a data management unit configured to delegate the exact string match operation to the first search circuit and to delegate the inexact string match operation to the second search circuit.