We introduce a runtime verification framework for programmable switches that complements static analysis. To evaluate our approach, we design and develop P6, a runtime verification system that automatically detects, localizes, and patches software bugs in P4 programs. Bugs are reported via a violation of pre-specified expected behavior that is captured by P6. P6 is based on machine learning-guided fuzzing that tests P4 switch non-intrusively, i.e., without modifying the P4 program for detecting runtime bugs. This enables an automated and real-time localization and patching of bugs. We used a P6 prototype to detect and patch existing bugs in various publicly available P4 application programs deployed on two different switch platforms, namely, behavioral model (bmv2) and Tofino. Our evaluation shows that P6 significantly outperforms bug detection baselines while generating fewer packets and patches bugs in large P4 programs, e.g., switch.p4 without triggering any regressions.

We make a case for a distributed hash table lookup in the network data plane. We argue that the lookup time performance of distributed hash tables can be further improved via an in-network data plane implementation. To this end, we introduce No-hop, an in-network distributed hash table implementation, which leverages the data plane programmability at line rate gained from P4. Our initial results of transporting distributed hash table logic from hosts' user space to the fast path of switches in the network data plane are promising. We show that No-hop improves the performance of locating the responsible host and maintains the properties of distributed hash tables while outperforming two baselines.

We design, develop, and evaluate P6, an automated approach to (a) detect, (b) localize, and (c) patch software bugs in P4 programs. Bugs are reported via a violation of pre-specified expected behavior that is captured by P6. P6 is based on machine learning-guided fuzzing that tests P4 switch non-intrusively, i.e., without modifying the P4 program for detecting runtime bugs. This enables an automated and real-time localization and patching of bugs. We used a P6 prototype to detect and patch existing bugs in various publicly available P4 application programs deployed on two different switch platforms: behavioral model (bmv2) and Tofino. Our evaluation shows that P6 significantly outperforms bug detection baselines while generating fewer packets and patches bugs in large P4 programs such as switch.p4 without triggering any regressions.