| 摘要 |
Efficient Content Addressable Memory (CAM)-based techniques for performing string searches in packet payloads. Hashes are performed on hash keys comprising overlapping sub-strings in one or more search strings. The resulting hash values are stored in a CAM. During packet processing operations, a search of the packet payload data is made to determine if any of the search strings are present. Hashes are performed on non-overlapping sub-strings in the payload data, and the hash results are submitted to the CAM for comparison with the previously-generated search string hash values. If no CAM hits result, the payload data does not contain any of the search strings, while a CAM hit indicates that at least one of the search strings might be present in the payload data. In this instance, a full string comparison is made between the search strings (or an identified search string) and strings in the payload data to verify whether a search string is actually present.
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