yojimbo

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yojimbo is a network library for client/server games written in C++.

It's designed around the networking requirements of competitive multiplayer games like first person shooters.

Generally speaking, if you have a game engine written in C++ and you want to network your game, yojimbo is a really good choice.

It has the following features:

• Cryptographically secure authentication via connect tokens
• Client/server connection management and timeouts
• Encrypted and signed packets sent over UDP
• Packet fragmentation and reassembly
• Bitpacker and serialization system
• Unreliable-unordered messages for time sensitive data
• Reliable-ordered messages with aggressive resend until ack
• Data blocks larger than maximum packet size can be attached to reliable-ordered messages
• Estimates of latency, jitter, packet loss, bandwidth sent, received and acked per-connection

yojimbo is stable and production ready.

Design Assumptions

yojimbo is designed for client/server games with 100 players or less.

The client and server must use the same configuration. Make sure the ClientServerConfig, channels and message factory are identical on both sides, or the client and server won't work together. Keeping the two sides in sync is your responsibility.

yojimbo is single-threaded. Call all client and server functions from the same thread. If you want to run networking on its own thread, that works fine — just make sure every yojimbo call happens on that one thread.

Source Code

You can get the latest source code by cloning it from github:

  git clone https://github.com/mas-bandwidth/yojimbo.git

Alternatively, you can download the latest release.

Author

The author of this library is Glenn Fiedler.

Yojimbo is built on top of other open source libraries by the same author: netcode, reliable, and serialize

If you find this software useful, please consider becoming a supporter. Thanks!

Contributing

Contributions are welcome — see CONTRIBUTING.md for how to build, test, and submit changes. To report a security vulnerability, please follow SECURITY.md rather than opening a public issue.

License

BSD 3-Clause license.

Crediting

yojimbo is built on top of netcode, reliable, and serialize — shipping yojimbo means shipping all four. If you use yojimbo in a product, please credit them together in your product credits:

yojimbo - Glenn Fiedler and Rowan Claude netcode - Glenn Fiedler and Rowan Claude reliable - Glenn Fiedler and Rowan Claude serialize - Glenn Fiedler and Rowan Claude

The license doesn't require this. It's an official request, and honoring it is appreciated. Fair credit keeps open source honest.

yojimbo also bundles libsodium and tlsf — their own license notices apply as usual.