yojimbo VS bitproto

yojimbo/ netcode/ reliable, all developped by Glenn Fidler, author of GafferOnGames

They really just didn't know how to go about building a complex online game or what that entails. At one point they were trying to donate to open source networking projects that were still in development and not production-ready in hopes they'd help them make their game, you'll see them listed as sponsors of yojimbo for example. It was bizarre to watch.

I can't remember exactly how best to handle this (Glenn's yojimbo project is probably your best bet for a concrete implementation), but here's an idea: buffer and ACK some packets (e.g. up to N packets following your missing packet) and discard everything else (without ACK) until the missing one shows up. The protocol will then continuously try to send your missing packet, in addition to the packets you've intentionally not ACK'd. Once the missing packet shows up you can process it and any buffered packets up to your next missing packet and repeat.

You may want to take a look at yojimbo , looks like it will fit your requirements pretty well.

And has his own C++ library for transmitting messages over UDP protocol https://github.com/networkprotocol/yojimbo

I had a similar use case for embedded microcontroller work. Unfortunately, the only one that I found that lets you have bit-level control is bitproto. The problem with all these protocol formats is that they require generated sources to be included in your project at compile time.