Networking & Protocol#

Protocol States#

Void implements the Minecraft protocol state machine with six states:

pub enum State {
    Handshake     = 0x0,
    Status        = 0x1,
    Login         = 0x2,
    Transfer      = 0x3,
    Configuration = 0x4,
    Play          = 0x5,
}

The active state determines which packets are valid. Each client entity tracks its state via the ConnectionState component.

Connection Lifecycle#

Full Join Flow#

Server List Ping#

When a client connects with next_state = 1 (Status):

Packet Handling Pipeline#

On every tick during PreUpdate:

1. Drain all packets from the incoming channel
2. For each packet:
   • Look up or create the client entity in ClientToEntityMap
   • Read the entity's ConnectionState
   • Decode the raw packet bytes using the protocol crate
   • Call the appropriate handle_{state}_packet() function
3. Drain the disconnect channel and despawn disconnected entities

fn dispatch_packet(world, client_id, entity, packet) {
    match state {
        Handshake     => handlers::handshake::handle_handshake_packet(..),
        Status        => handlers::status::handle_status_packet(..),
        Login         => handlers::login::handle_login_packet(..),
        Configuration => handlers::configuration::handle_configuration_packet(..),
        Play          => handlers::play::handle_play_packet(..),
    }
}

Keep-Alive System#

The server sends periodic keep-alive packets to detect dead connections:

• Interval: 200 ticks (10 seconds at 20 TPS)
• Mechanism: Each tick, KeepAliveTicker increments. When the interval is reached, a KeepAlive packet with a timestamp ID is sent to all ready players.
• Tracking: KeepAliveState on each player tracks the last sent ID and whether a response is pending.
• Timeout: If a player hasn't responded when the next keep-alive is due, a warning is logged and the keep-alive is skipped for that player.

Status Response#

When a client pings the server list, the response includes:

Current Limitations#

• No encryption: The server does not implement Mojang authentication or encrypted connections. All traffic is plaintext.
• No compression: Packet compression is not implemented. All packets are sent at full size.
• No Transfer state: The Transfer protocol state is defined but not handled.