A Formally Verified NAT Stack

Prior work proved a stateful NAT network function to be, crash-free, memory safe and semantically correct [29]. Their toolchain verifies the network function code while assuming the underlying kernel-bypass framework, drivers, operating system, and hardware to be correct. We extend the toolchain to verify the kernel-bypass framework and a NIC driver in the context of the NAT. We uncover bugs in both the framework and the driver. Our code is publicly available [28].