From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Shane Freeder <theboyetronic@gmail.com>
Date: Wed, 19 Aug 2020 05:05:54 +0100
Subject: [PATCH] Buffer joins to world

This patch buffers the number of logins which will attempt to join
the world per tick, this attempts to reduce the impact that join floods
has on the server

diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
@@ -0,0 +0,0 @@ public class PaperConfig {
             maxPlayerAutoSavePerTick = (playerAutoSaveRate == -1 || playerAutoSaveRate > 100) ? 10 : 20;
         }
     }
+
+    public static int maxJoinsPerTick;
+    private static void maxJoinsPerTick() {
+        maxJoinsPerTick = getInt("settings.max-joins-per-tick", 3);
+    }
 }
diff --git a/src/main/java/net/minecraft/network/NetworkManager.java b/src/main/java/net/minecraft/network/NetworkManager.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/net/minecraft/network/NetworkManager.java
+++ b/src/main/java/net/minecraft/network/NetworkManager.java
@@ -0,0 +0,0 @@ import net.minecraft.network.protocol.game.PacketPlayOutTabComplete;
 import net.minecraft.network.protocol.game.PacketPlayOutTitle;
 import net.minecraft.server.CancelledPacketHandleException;
 import net.minecraft.server.MCUtil;
+import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.level.EntityPlayer;
 import net.minecraft.server.network.LoginListener;
 import net.minecraft.server.network.PlayerConnection;
@@ -0,0 +0,0 @@ public class NetworkManager extends SimpleChannelInboundHandler<Packet<?>> {
     }
     // Paper end
 
+    private static final int MAX_PER_TICK = com.destroystokyo.paper.PaperConfig.maxJoinsPerTick; // Paper
+    private static int joinAttemptsThisTick; // Paper
+    private static int currTick; // Paper
     public void a() {
         this.p();
+        // Paper start
+        if (currTick != MinecraftServer.currentTick) {
+            currTick = MinecraftServer.currentTick;
+            joinAttemptsThisTick = 0;
+        }
+        // Paper end
         if (this.packetListener instanceof LoginListener) {
+            if ( ((LoginListener) this.packetListener).getLoginState() != LoginListener.EnumProtocolState.READY_TO_ACCEPT // Paper
+                     || (joinAttemptsThisTick++ < MAX_PER_TICK)) { // Paper - limit the number of joins which can be processed each tick
             ((LoginListener) this.packetListener).tick();
+            } // Paper
         }
 
         if (this.packetListener instanceof PlayerConnection) {
diff --git a/src/main/java/net/minecraft/server/network/LoginListener.java b/src/main/java/net/minecraft/server/network/LoginListener.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/net/minecraft/server/network/LoginListener.java
+++ b/src/main/java/net/minecraft/server/network/LoginListener.java
@@ -0,0 +0,0 @@ public class LoginListener implements PacketLoginInListener {
         return new GameProfile(uuid, gameprofile.getName());
     }
 
-    static enum EnumProtocolState {
+    public enum EnumProtocolState { // Paper - package private -> public
 
         HELLO, KEY, AUTHENTICATING, NEGOTIATING, READY_TO_ACCEPT, DELAY_ACCEPT, ACCEPTED;