NIC drivers
EVL implements a lightweight network stack which supports packet-oriented and UDP protocols over Ethernet. Although EVL does not require the NIC driver code to be oob-capable, i.e. conveying ingress and egress traffic directly from the out-of-band execution stage, having such support in place is the only way to have a complete, end-to-end real-time networking path, from the Ethernet wire to the application code. In other words, one may still use stock controller drivers along with the EVL network stack, at the expense of the real-time performance which would depend on the low-latency capabilities of the host kernel.
This section details the changes required for adding such out-of-band I/O capabilities to an existing network interface controller driver from the stock Linux kernel, using the Dovetail interface which extends the common networking support. Although the EVL network stack currently deals with protocols over an Ethernet medium, these changes are medium-agnostic.
