ClickNF: a Modular Stack for Custom Network Functions

Network function virtualization has recently allowed specialized equipment to be replaced with equivalent software implementation. The Click router was a first step in this direction, defining a modular platform for generalized packet processing. Despite its major impact, however, Click does not provides native L4 implementation and only uses nonblocking I/O, limiting its scope to L2-L3 network functions. To overcome these limitations we introduce ClickNF, which provides modular transport and application-layer building blocks for the development of middleboxes and server-side network functions. We evaluate ClickNF to highlight its state-of-the-art performance and showcase its modularity by composing complex functions from simple elements. ClickNF is open source and publicly available.