qemu-nc
A dumb netcat for QEMU's -netdev socket protocol.
tl;dr the format is <u32be: length><ethernet frame data>
sent as a stream of bytes over the wire. Nothing more.
Why?
I'm developing an operating system and wanted to be able to check that implementations of the network are working correctly. To do that, I'd need to test the format of ethernet packets coming out of the machine under QEMU in a generic way so that QEMU can be added as a kernel/system integration test backend along with some custom PCBs used for testing baremetal setups.
I didn't want to have to extend QEMU (due to equal parts time, complexity, and licensing) so instead looked for other ways to instrument the network of the SUT. This appears to be the most generic, low-level, "raw" way to do so.
I have not tried to send packets back over the wire but I would imagine it works the same.
Which operating system?
Usage
Build, run. It'll give you a port (it's not the same each time).
Run QEMU with something like the following:
qemu-system-x86_64 -nographic -netdev socket,id=n1,connect=127.0.0.1:$PORT -device e1000,netdev=n1,mac=52:54:00:12:34:56You should start seeing packets come across qemu-nc.
License
Copyright © 2023, Josh Junon. Licensed under the WTFPL. There's not a lot of code here anyway, so do whatever you want with it. Treat it as CC0 or PD if you want, I really honestly don't care.