A domain-specific language for protocol stack implementation in embedded systems

Abstract: Embedded network software has become increasingly interesting for both research and business as more and more networked embedded systems emerge. Well-known infrastructure protocol stacks are reimplemented on new embedded hardware and software architectures. New requirements of modern applications and devices require to implement newly designed or revised protocols. However, implementing protocol stacks for embedded systems remains a time-consuming and error-prone task due to the complexity and performancecritical nature of network software. It is even more so when targeting resource constrained embedded systems: implementations have to minimize energy consumption, memory usage etc., while programming efficiency is needed to improve on time-to-market, scalability, maintainability and product evolution. Therefore, it is worth researching on how to make protocol stack implementations for embedded systems both easier and more likely to be correct within the resource limits.In the work presented in this thesis, we take a language-based approach and aim to facilitate the implementation of protocol stacks while realizing performance demands and being aware of energy consumption and memory usage within the constraints imposed by embedded systems. We give background on DSL implementation techniques, investigate common practices in network protocol development to determine the potential of domain-specifi languages (DSLs) for embedded network software, and propose a domain-specifi embedded language (DSEL), Protege (Protocol Implementation Generator), for declaratively describing overlaid protocol stacks. In Protege, a high-level packet specification is dually compiled into an internal data representation for protocol logic implementation, and packet processing methods which are then integrated into the dataflow framework of a protocol overlay specification. Constructs for finite state machines allow to specify protocol logic in a concise manner, close to the protocol specification style. Protege specifications are compiled to highly portable C code for various architectures.Four attached scientific papers report our main results in more detail: an embedded implementation of the data description calculus in Haskell, a compilation framework for generating packet processing code with overlays, the domain-specific language Protege in overview (including embedding techniques and runtime system features), and a real-world case study implementing an industrial application protocol.