HandshakeListener.java

package net.minecraft.server;

// CraftBukkit start
import java.net.InetAddress;
// CraftBukkit end
import java.util.Map;

import com.koloboke.collect.map.hash.HashObjLongMaps;

public class HandshakeListener implements PacketHandshakingInListener {

    private static final com.google.gson.Gson gson = new com.google.gson.Gson(); // Spigot
    // CraftBukkit start - add fields
    private static final Map<InetAddress, Long> throttleTracker = HashObjLongMaps.newMutableMap();
    private static int throttleCounter = 0;
    // CraftBukkit end

    private final MinecraftServer a;
    private final NetworkManager b;

    public HandshakeListener(MinecraftServer minecraftserver, NetworkManager networkmanager) {
        this.a = minecraftserver;
        this.b = networkmanager;
    }

    @Override
    public void a(PacketHandshakingInSetProtocol packethandshakinginsetprotocol) {
        switch (packethandshakinginsetprotocol.a()) {
            case LOGIN:
                this.b.setProtocol(EnumProtocol.LOGIN);
                ChatComponentText chatcomponenttext;

                // CraftBukkit start - Connection throttle
                try {
                    long currentTime = System.currentTimeMillis();
                    long connectionThrottle = MinecraftServer.getServer().server.getConnectionThrottle();
                    InetAddress address = ((java.net.InetSocketAddress) this.b.getSocketAddress()).getAddress();

                    synchronized (throttleTracker) {
                        if (throttleTracker.containsKey(address) && !"127.0.0.1".equals(address.getHostAddress()) && currentTime - throttleTracker.get(address) < connectionThrottle) {
                            throttleTracker.put(address, currentTime);
                            chatcomponenttext = new ChatComponentText("Connection throttled! Please wait before reconnecting.");
                            this.b.sendPacket(new PacketLoginOutDisconnect(chatcomponenttext));
                            this.b.close(chatcomponenttext);
                            return;
                        }

                        throttleTracker.put(address, currentTime);
                        throttleCounter++;
                        if (throttleCounter > 200) {
                            throttleCounter = 0;

                            // Cleanup stale entries
                            java.util.Iterator iter = throttleTracker.entrySet().iterator();
                            while (iter.hasNext()) {
                                java.util.Map.Entry<InetAddress, Long> entry = (java.util.Map.Entry) iter.next();
                                if (entry.getValue() > connectionThrottle) {
                                    iter.remove();
                                }
                            }
                        }
                    }
                } catch (Throwable t) {
                    org.apache.logging.log4j.LogManager.getLogger().debug("Failed to check connection throttle", t);
                }
                // CraftBukkit end

                if (packethandshakinginsetprotocol.b() > 316) {
                    chatcomponenttext = new ChatComponentText( java.text.MessageFormat.format( org.spigotmc.SpigotConfig.outdatedServerMessage.replaceAll("'", "''"), "1.11.2" ) ); // Spigot
                    this.b.sendPacket(new PacketLoginOutDisconnect(chatcomponenttext));
                    this.b.close(chatcomponenttext);
                } else if (packethandshakinginsetprotocol.b() < 316) {
                    chatcomponenttext = new ChatComponentText( java.text.MessageFormat.format( org.spigotmc.SpigotConfig.outdatedClientMessage.replaceAll("'", "''"), "1.11.2" ) ); // Spigot
                    this.b.sendPacket(new PacketLoginOutDisconnect(chatcomponenttext));
                    this.b.close(chatcomponenttext);
                } else {
                    this.b.setPacketListener(new LoginListener(this.a, this.b));
                    // Paper start - handshake event
                    boolean proxyLogicEnabled = org.spigotmc.SpigotConfig.bungee;
                    boolean handledByEvent = false;
                    // Try and handle the handshake through the event
                    if (com.destroystokyo.paper.event.player.PlayerHandshakeEvent.getHandlerList().getRegisteredListeners().length != 0) { // Hello? Can you hear me?
                        com.destroystokyo.paper.event.player.PlayerHandshakeEvent event = new com.destroystokyo.paper.event.player.PlayerHandshakeEvent(packethandshakinginsetprotocol.hostname, !proxyLogicEnabled);
                        if (event.callEvent()) {
                            // If we've failed somehow, let the client know so and go no further.
                            if (event.isFailed()) {
                                chatcomponenttext = new ChatComponentText(event.getFailMessage());
                                this.b.sendPacket(new PacketLoginOutDisconnect(chatcomponenttext));
                                this.b.close(chatcomponenttext);
                                return;
                            }

                            packethandshakinginsetprotocol.hostname = event.getServerHostname();
                            this.b.l = new java.net.InetSocketAddress(event.getSocketAddressHostname(), ((java.net.InetSocketAddress) this.b.getSocketAddress()).getPort());
                            this.b.spoofedUUID = event.getUniqueId();
                            this.b.spoofedProfile = gson.fromJson(event.getPropertiesJson(), com.mojang.authlib.properties.Property[].class);
                            handledByEvent = true; // Hooray, we did it!
                        }
                    }
                    // Don't try and handle default logic if it's been handled by the event.
                    if (!handledByEvent && proxyLogicEnabled) {
                        // Paper end
                        // Spigot Start
                        //if (org.spigotmc.SpigotConfig.bungee) { // Paper - comment out, we check above!
                        String[] split = packethandshakinginsetprotocol.hostname.split("\00");
                        if ( split.length == 3 || split.length == 4 ) {
                            packethandshakinginsetprotocol.hostname = split[0];
                            b.l = new java.net.InetSocketAddress(split[1], ((java.net.InetSocketAddress) b.getSocketAddress()).getPort());
                            b.spoofedUUID = com.mojang.util.UUIDTypeAdapter.fromString( split[2] );
                        } else
                        {
                            chatcomponenttext = new ChatComponentText("If you wish to use IP forwarding, please enable it in your BungeeCord config as well!");
                            this.b.sendPacket(new PacketLoginOutDisconnect(chatcomponenttext));
                            this.b.close(chatcomponenttext);
                            return;
                        }
                        if ( split.length == 4 )
                        {
                            b.spoofedProfile = gson.fromJson(split[3], com.mojang.authlib.properties.Property[].class);
                        }
                    }
                    // Spigot End
                    ((LoginListener) this.b.i()).hostname = packethandshakinginsetprotocol.hostname + ":" + packethandshakinginsetprotocol.port; // CraftBukkit - set hostname
                }
                break;

            case STATUS:
                this.b.setProtocol(EnumProtocol.STATUS);
                this.b.setPacketListener(new PacketStatusListener(this.a, this.b));
                break;

            default:
                throw new UnsupportedOperationException("Invalid intention " + packethandshakinginsetprotocol.a());
        }

    }

    @Override
    public void a(IChatBaseComponent ichatbasecomponent) {}
}