P4 is a new language for programming network data planes. The language provides domain-specific constructs for describing the input-output formats and functionality of packet-processing pipelines. Unfortunately P4 programs can go wrong in a variety of interesting and frustrating ways including reading uninitialized data, generating malformed packets, and failing to handle exceptions. In this talk, I will present the design and implementation of p4v, a tool for verifying P4 programs. The tool is based on classic software verification techniques (due to Hoare, Dijkstra, Flanagan, Leino, etc.), but adds several important innovations: a novel mechanism for incorporating control-plane assumptions and domain-specific optimizations, both of which are needed to scale up to large programs. I will discuss our experiences applying p4v to a variety of real-world programs including switch.p4, a large program that implements the functionality of a conventional switch.

p4v is joint work with Bill Hallahan (Yale), JK Lee (Barefoot), Cole Schlesinger (Barefoot), Steffen Smolks (Cornell), Robert Soule (Barefoot and USI), and Han Wang (Barefoot).

Nate Foster is an Associate Professor of Computer Science at Cornell University. The goal of his research is to develop languages and tools that make it easy for programmers to build secure and reliable systems. His current work focuses on the design and implementation of languages for programming software-defined networks. In the past he has also worked on bidirectional languages (also known as “lenses”), database query languages, data provenance, type systems, mechanized proof, and formal semantics. He received a PhD in Computer Science from the University of Pennsylvania, an MPhil in History and Philosophy of Science from Cambridge University, and a BA in Computer Science from Williams College. His awards include a Sloan Research Fellowship, an NSF CAREER Award, a Most Influential POPL Paper Award, a Tien ’72 Teaching Award, a Google Research Award, a Yahoo! Academic Career Enhancement Award, a Cornell Engineering Research Excellence Award, and the Morris and Dorothy Rubinoff Award.