Enabling Flexible Packet Filtering Through Dynamic Code Generation

Despite its efficiency, the general approach of hardcoding protocol format descriptions in packet processing applications suffers from many limitations. Among the others, the lack of flexibility when needing to extend the software for supporting new protocols, and the proliferation of modules with similar functionality between different applications, resulting in decreased maintainability. The NetPDL language was defined for overcoming such limitations, allowing decoupling applications from the knowledge of the format of protocol headers. The main criticism to NetPDL relates to its supposed performance penalties; this paper demonstrates that this language can be effectively used for the dynamic generation of optimized, i.e. efficient and fast, packet-processing code, and presents the architecture of a compiler implemented for such purpose.