- Separated player handling and creation from network interfaces
- Rewire disconnects to make them not be recursive
- Batching now uses sessions instead of players
- Fixed DisconnectPacket getting sent to players who disconnect of their own accord
This introduces several new session handlers, splitting up session handling into several new states:
- Login: Only allows handling the LoginPacket. This is the only time LoginPacket can be sent, and it'll be discarded when sent at any other time.
- Resource packs: Handles only the resource packs sequence (downloading packs and such). This is the only time ResourcePackClientResponse and ResourcePackChunkRequest will be handled.
- Pre-spawn: Only chunk radius requests are accepted during this state.
SimpleNetworkHandler handles all the "rest" of the logic that hasn't yet been separated out into their own dedicated handlers. There's also a NullNetworkHandler which discards all packets while it's active.
This solves a large number of issues with the security of the login sequence. It solves a range of possible DoS attacks and crashes, while also allowing great code simplification and cleanup.
