Reliudp: Custom reliable udp protocol for Rust

(Work in progress)

Short version

Features:

• No unsafe code
• All the downsides of UDP with the sluggishness of TCP
• Slow as a camel
• I'm not sure how it works
• Experimental
• Not safe against DOS attacks

Downsides:

• It works

Long version

This crate is meant be be akin to https://github.com/BonsaiDen/cobalt-rs, in the sense that it provides:

• Connection over UDP
• Guarantee that a message arrives at destination
• Extremely Low Latency

This crate was mainly made in mind for use cases where bandwidth is plentifull and low latency is of the utmost importance. Specifically, online multiplayer gaming.

What is the advantage over raw UDP?

• Keeps track of connection, handles timeouts (uses 2-way handshake)
• Automatic packet re-ordering
• Additional CRC32 check over IP packets, reducing chances of corrupted data to almost none
• Possibility to make sure a packet arrives at destination

What is the advantage over raw TCP?

• Not stream based
• You choose which packets should be discarded if it doesn't go through the first time:
  • Key messages will make sure to go through with an Ack system
  • Forgettable messages will be discarded if packet wasn't complete the first time

What are the drawbacks ?

• (Planned) No network congestion handling
• (Planned) No test coverage
• (Planned) No optionnal SSL and/or other secure way to send data: everything is plaintext
• (Planned) No error correction codes of any kind (Hamming, ...)
• (May change in the future) Payloads are limited in size (around ~300KB)
• Untested against DOS attacks
• No Futures support. Will probably never have it.

License

MIT