Network Protocol

[ACBob]

I need to define a proper protocol for the network, Looking at Minecraft it seems to have a shitton of packet types without much care in the world for saving them (Cuberite as reference on 1.8) so I can do the same, right? Right?

This doesn't clear up how MC does player input, I'm still thinking looking should be 100% client-side (and set to the server, although this might have issues if the client lies) and use a source-like ConCommand system where inputs are commands executed on the server.

[ACBob]

Important Question:\ Encryption, Yay or Nay?

After that, How do we do it!?\ Perhaps a password hash sent to the server ala Minetest?

[ACBob]

as of commit ac9437e this is being worked on

[ACBob]

An Idea I'd had:\ It's loosely based on Minecraft Classic.

Client -> Server

Packet ID	Info	Notes
Player ID	Protocol Version, Username
Set Block	Position, BlockType
Chat Message	Message
Pong		Contains no data
Leave		Contains no data
Chunk Request	X,Y,Z
Command Executed	Command, Command Args	Used for Movement ConCommands (#11)

Server -> Client

Packed ID	Info	Notes
Server Info	Protocol Version, Server Name, Server Description
Keep Alive		Contains no data
Chunk Data	X, Y, Z, nBlocks, Blocks (1D Array)
Set Block	X, Y, Z, Block Type	Sent to ALL clients, even the client that might've instigated it
Player Spawn	X,Y,Z, Pitch, Yaw
Chat Message	Username, Message
Disconnect	isKick, Kick Mesasge
Convar Update	ConVarName, Value	Used for CVars marked notify (i.e sv_cheats)

Example

Joining the server for the first time, Downloading the chunk at spawn and then leaving:

Client	DIR	Server
Player ID	->	Test name, protocol version, etc.
Set local variables, Test protocol, etc.	<-	Server Info
Set local coordinates, orientation	<-	Player Spawn
Chunk Request	->	Load the chunk data and spit it back
Handle chunk data, generating mesh & stuff	<-	Chunk Data
...	...	...
Send Pong	<-	Keep Alive
Pong	->	Don't kick player
...	...	...
Leave	->	Handle leaving, kick player*

*We kick the player to stop fraudulent leaving, where the client doesn't actually disconnect - The server decides when you're done.

[ACBob]

Further investigation into how MC does it shows that the server reads your render distance, and then decides itself to send you chunks. This is actually really smart, so let's do that too.

The client can ignore any chunks outside its' set render distance in the case of a malicious server, and the server can curb to a maximum render distance by not sending anymore.

This also means a client can't just go "HEY I'M GOING TO LOOP FROM -infinity TO +infinity IN ALL DIRECTIONS, GIMME CHUNKS" and then ignore it, which would be a funny but unfortunate attack.

[ACBob]

What we have atm seems to work alright, but is too minecraft based. Doesn't even implement #11!

Good for a prototype, needs changed and fixed.

[ACBob]

While technically we have something working, there's always room for improvement.