P4 is widely adopted for programming data planes in software-defined networking. Formal verification of P4 programs is essential to ensure network reliability and security. However, existing P4 verifiers overlook the stateful nature of packet processing, rendering them inadequate for verifying complex stateful P4 programs.In this paper, we introduce a novel concept called packet invariants to address the stateful aspects of P4 programs. We present an automated verification tool specifically designed for stateful P4 programs. This algorithm efficiently discovers and validates packet invariants in a data-driven manner, offering a novel and effective verification approach for stateful P4 programs. To the best of our knowledge, this approach represents the first attempt to generate and leverage domain-specific invariants for P4 program verification. We implement our approach in a prototype tool called P4Inv. Experimental results demonstrate its effectiveness in verifying stateful P4 programs.

P4 is a mainstream language for Software Defined Network (SDN) data planes. P4 is designed to achieve target-independent, protocol-independent, and configurable SDN data planes. However, logic errors may occur in P4 programs, resulting in improper packet processing, which may cause serious network errors and information disclosure. In addition, P4 programs contain many branches and thus are more challenging to ensure correctness. Formal verification is a powerful technique to verify the correctness of P4 programs. Unfortunately, current P4 verification studies lack basic toolchains, and their intermediate languages are not expressive enough. We present P4b, an efficient translator from P4 programs to Boogie, a verification-oriented intermediate representation. We provide formal translation rules to ensure the correctness of the translation process. The translated results can be verified by the toolchain of Boogie. We conducted experiments on 170 P4 programs collected from GitHub, and the experimental results demonstrate that our translator is useful and practical. The screencast is available at https://youtu.be/8_rEj3QFQeM. The tool is available at https://github.com/Invincibleyc/P4B-Translator.