User Space Network Drivers

The rise of user space packet processing frameworks like DPDK and netmap makes low-level code more accessible to developers and researchers. Previously, driver code was hidden in the kernel and rarely modified-or even looked at-by developers working at higher layers. These barriers are gone nowadays, yet developers still treat user space drivers as black-boxes magically accelerating applications. We want to change this: every researcher building network applications should understand the intricacies of the underlying drivers, especially if they impact performance. We present ixy, a user space network driver designed for simplicity and educational purposes. Ixy focuses on the bare essentials of user space packet processing: a packet forwarder including the whole NIC driver uses less than 1000 lines of C code. Our code is available as free and open source under the BSD license at https://github.com/emmericp/ixy.