Safe, modular packet pipeline programming

Abstract

The P4 language and programmable switch hardware, like the Intel Tofino, have made it possible for network engineers to write new programs that customize operation of computer networks, thereby improving performance, fault-tolerance, energy use, and security. Unfortunately, possible does not mean easy —there are many implicit constraints that programmers must obey if they wish their programs to compile to specialized networking hardware. In particular, all computations on the same switch must access data structures in a consistent order, or it will not be possible to lay that data out along the switch’s packet-processing pipeline. In this paper, we define Lucid 2.0, a new language and type system that guarantees programs access data in a consistent order and hence are pipeline-safe . Lucid 2.0 builds on top of the original Lucid language, which is also pipeline-safe, but lacks the features needed for modular construction of data structure libraries. Hence, Lucid 2.0 adds (1) polymorphism and ordering constraints for code reuse; (2) abstract, hierarchical pipeline locations and data types to support information hiding; (3) compile-time constructors, vectors and loops to allow for construction of flexible data structures; and (4) type inference to lessen the burden of program annotations. We develop the meta-theory of Lucid 2.0, prove soundness, and show how to encode constraint checking as an SMT problem. We demonstrate the utility of Lucid 2.0 by developing a suite of useful networking libraries and applications that exploit our new language features, including Bloom filters, sketches, cuckoo hash tables, distributed firewalls, DNS reflection defenses, network address translators (NATs) and a probabilistic traffic monitoring service.

eHDL: Turning eBPF/XDP Programs into Hardware Designs for the NIC

“…Network HLS. The HLS tools dedicated to networking use cases usually adopt the P4 language [3], and target both FPGA [20,43,44] and programmable ASIC platforms [17,25,40]. P4 is a domainspecific language specialized to describe packet header parsing and classification tasks, and was developed in parallel with a reference hardware architecture called PISA, directly deriving assumptions and programming models from earlier work on programmable switching chips [4].…”