amethyst/lib/servers/handhsake.ex
2024-07-10 09:13:03 +02:00

73 lines
2.4 KiB
Elixir

# Amethyst - An experimental Minecraft server written in Elixir.
# Copyright (C) 2024 KodiCraft
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
defmodule Amethyst.Server.Handshake do
@moduledoc """
This module contains the logic for the Handshake stage of the server.
"""
require Logger
use Amethyst.Server
alias Amethyst.Minecraft.Read
@impl true
def init(state) do
state
end
## DESERIALIZATION
@impl true
# Handshake https://wiki.vg/Protocol#Handshake
@spec deserialize(0, binary()) ::
{:handshake, any(), any(), any(), :login | :status | :transfer}
def deserialize(0x00, <<data::binary>>) do
{[ver, addr, port, next], ""} = Read.start(data) |> Read.varint() |> Read.string() |> Read.ushort() |> Read.varint() |> Read.stop()
next = case next do
1 -> :status
2 -> :login
3 -> :transfer
_ -> raise RuntimeError, "Client requested moving to an unknown state!"
end
{:handshake, ver, addr, port, next}
end
def deserialize(type, _) do
raise RuntimeError, "Got unknown packet type #{type}!"
end
## SERIALIZATION
@impl true
def serialize(_) do
raise RuntimeError, "No packets can be transmitted while still in the handshake stage!"
end
## HANDLING
@impl true
# Handshake https://wiki.vg/Protocol#Handshake
@spec handle(any(), any(), any()) :: no_return()
def handle({:handshake, 767, addr, port, next}, client, state) do
Logger.info("Got handshake, version 767 on #{addr}:#{port}. Wants to move to #{next}")
case next do
:status -> Amethyst.Server.Status.serve(client, state)
:login -> Amethyst.Server.Login.serve(client, state)
_ -> raise RuntimeError, "Unhandled move to next mode #{next}"
end
end
def handle(tuple, _, state) do
Logger.error("Unhandled but known packet #{elem(tuple, 0)}")
{:unhandled, state}
end
end