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.
This consolidates the Player entity construction and makes it more organized and consistent. There is of course a lot more work to do apart from this on player construction.
all the things we cared about in here don't exist anymore, so there's no sense in the handler still existing. It can be restored when we want to use the things it still does.
DataPacketSendEvent and DataPacketReceiveEvent will no longer capture BatchPackets
In most places strings are now used instead of DataPackets, to remove limitations on what data can be sent to a network interface
Removed CraftingManager's cyclic dependency on Server
There is a lot more work to do aside from this, but this commit is intended to clean up what is necessary to fix the handling of BatchPacket.
This reverts commit 0081e30a896a730f9598353353f6ee258803850e.
The logic introduced by this commit is correct in MC JAVA 1.9+. Unfortunately, nobody likes 1.9+ for combat.
Some testing in MCPE vanilla made it apparent that this logic isn't correct for MCPE. The old logic is correct for pre-1.9 knockback.
it's possible to walk off a tower while flying without moving vertically, and this code previously wouldn't detect that, leaving a gaping hole in the anti-cheat.
