Proprietary device drivers, dedicated applications, and their ilk are the bane of the open-source hacker. If only we could snoop on every device out there, recording the “secret” USB transactions as they go over the wire, we’d have a chance.

[Emir Mrkaljević]’s tool, usb-rea, aims to make this process a whole lot less painful. The workflow is like this: you start capturing on USB, make an annotation about what action you’re taking, press the button a few times, and then move on to the next action.

sudo modprobe usbmon
usb-rea capture start -o lamp.pcapng
usb-rea mark -m lamp.pcapng.actions.json "brightness 0%"    # then click it in the vendor app
usb-rea mark -m lamp.pcapng.actions.json "brightness 50%"   # ...repeat for 3+ values per setting
usb-rea capture stop
usb-rea report lamp.pcapng -o report.md
usb-rea scaffold lamp.pcapng -o lamp_driver.py
usb-rea dissector lamp.pcapng -o lamp.lua      # Wireshark dissector for the same protocol

Usb-rea records all the USB traffic, timestamps it relative to your actions, and gives you a report, a driver, and a Wireshark protocol dissector out the back side. There is even an MCP file so that you can hand off the grunt work to the bots, possibly enabling this to work closed-loop?

Of course, you don’t want to reinvent the wheel, so it’s fun to see that there’s also a usb-rea lookup command to see if your VID:PID is already in the dataset. Most of the devices are CPU coolers, RGB controllers, and other blinged-out computer peripherals, but we imagine that it’s a lot more broadly applicable. We looked for our mouse on the list, but it’s sadly not there.

Usb-rea is not a silver bullet to bring back abandoned peripherals from the grave, because you still need to run the proprietary driver during the recording. But if you get ahead of the game and document the protocols before the manufacturers abandon them, you stand a chance. Get recording!