We've developed a series of tiny ethernet switches (the SwitchBlox series) optimized for use in robotics and drones. Full disclosure, the hardware is not fully open source. However, we have developed a fully open-source (MIT License) software tool-chain that allows switch management features on our boards.
This software taps into the features of the onboard IP175G ethernet switch chip and is in two parts.
Part 1 is the firmware that runs on an STM32 onboard and talks to the IP175G ethernet chip to configure it. The firmware takes serial commands and turns them into MDIO commands to configure the ethernet chip.
Part 2 is the PyPI command-line interface that runs on a computer and allows configuration commands to be sent over UART to SwitchBlox.
Right now we've implemented port-based VLANs and port mirroring, but any of the IP175G features can be enabled by building on our platform.
Developed by Aaron Elijah and Josh Elijah, we're brothers ;)