«PFQ is a functional networking framework that allows efficient packets capture/transmission (10g+), in-kernel functional processing and packets steering across sockets/end-points. The framework enables the development of high-performance applications with different programming languages: C, C++11 and Haskell.» - http://www.pfq.io/
«In addition, a pure functional language designed for early stages applications is included: PFQ/lang. PFQ/lang is inspired by Haskell and allows for creation of small applications that run in kernel space, on top of network device drivers. Through PFQ/lang it is possible to create efficient bridges, port mirrors, simple firewalls, network balancers and so forth.» - 9000
Put more Haskell into your OS kernel! Note: they use plain GHC. - 9000