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

1 files changed, 50 insertions, 0 deletions

diff --git a/Spigot-Server-Patches/0556-Buffer-joins-to-world.patch b/Spigot-Server-Patches/0556-Buffer-joins-to-world.patch
new file mode 100644
index 0000000000..50ccd5c8e8
--- /dev/null
+++ b/Spigot-Server-Patches/0556-Buffer-joins-to-world.patch
@@ -0,0 +1,50 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Shane Freeder <[email protected]>
+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 5d4783e357218694ac52ec0ab5c030470cc6595f..671a7551458080d10613aa9111b77ed3cf1d25ca 100644
+--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
++++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
+@@ -446,4 +446,9 @@ public class PaperConfig {
+         allowPistonDuplication = getBoolean("settings.unsupported-settings.allow-piston-duplication", config.getBoolean("settings.unsupported-settings.allow-tnt-duplication", false));
+         set("settings.unsupported-settings.allow-tnt-duplication", null);
+     }
++
++    public static int maxJoinsPerTick;
++    private static void maxJoinsPerTick() {
++        getInt("settings.max-joins-per-tick", 3);
++    }
+ }
+diff --git a/src/main/java/net/minecraft/server/NetworkManager.java b/src/main/java/net/minecraft/server/NetworkManager.java
+index ed63bf3648153ce9ecab75e960c612337cbcbfe8..c06b70fa490a3bf91ea20c8405178420d62e7df2 100644
+--- a/src/main/java/net/minecraft/server/NetworkManager.java
++++ b/src/main/java/net/minecraft/server/NetworkManager.java
+@@ -363,10 +363,22 @@ 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.o();
++        // 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) {