PaperMC/Spigot-Server-Patches/0315-Handle-Large-Packets-disconnecting-client.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Tue, 27 Nov 2018 21:18:06 -0500
Subject: [PATCH] Handle Large Packets disconnecting client

If a players inventory is too big to send in a single packet,
split the inventory set into multiple packets instead.

diff --git a/src/main/java/net/minecraft/network/NetworkManager.java b/src/main/java/net/minecraft/network/NetworkManager.java
index 297820baef99e97e1216a64c527219e9ccc3e320..dc788d75a6a34fbbae990609bfbbd13ca6cdee5a 100644
--- a/src/main/java/net/minecraft/network/NetworkManager.java
+++ b/src/main/java/net/minecraft/network/NetworkManager.java
@@ -12,6 +12,7 @@ import io.netty.channel.epoll.EpollEventLoopGroup;
 import io.netty.channel.local.LocalChannel;
 import io.netty.channel.local.LocalServerChannel;
 import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.handler.codec.EncoderException; // Paper
 import io.netty.handler.timeout.TimeoutException;
 import io.netty.util.AttributeKey;
 import io.netty.util.concurrent.Future;
@@ -107,6 +108,15 @@ public class NetworkManager extends SimpleChannelInboundHandler<Packet<?>> {
     }
 
     public void exceptionCaught(ChannelHandlerContext channelhandlercontext, Throwable throwable) {
+        // Paper start
+        if (throwable instanceof EncoderException && throwable.getCause() instanceof PacketEncoder.PacketTooLargeException) {
+            if (((PacketEncoder.PacketTooLargeException) throwable.getCause()).getPacket().packetTooLarge(this)) {
+                return;
+            } else {
+                throwable = throwable.getCause();
+            }
+        }
+        // Paper end
         if (throwable instanceof SkipEncodeException) {
             NetworkManager.LOGGER.debug("Skipping packet due to errors", throwable.getCause());
         } else {
diff --git a/src/main/java/net/minecraft/network/PacketEncoder.java b/src/main/java/net/minecraft/network/PacketEncoder.java
index 2f6da89d6b25ba5144ec15b1bf0e8ed13278e85e..037d989522d24a55eced1c462d40a6dc2a7ecfce 100644
--- a/src/main/java/net/minecraft/network/PacketEncoder.java
+++ b/src/main/java/net/minecraft/network/PacketEncoder.java
@@ -53,7 +53,31 @@ public class PacketEncoder extends MessageToByteEncoder<Packet<?>> {
                         throw throwable;
                     }
                 }
+
+                // Paper start
+                int packetLength = bytebuf.readableBytes();
+                if (packetLength > MAX_PACKET_SIZE) {
+                    throw new PacketTooLargeException(packet, packetLength);
+                }
+                // Paper end
             }
         }
     }
+
+    // Paper start
+    private static int MAX_PACKET_SIZE = 2097152;
+
+    public static class PacketTooLargeException extends RuntimeException {
+        private final Packet<?> packet;
+
+        PacketTooLargeException(Packet<?> packet, int packetLength) {
+            super("PacketTooLarge - " + packet.getClass().getSimpleName() + " is " + packetLength + ". Max is " + MAX_PACKET_SIZE);
+            this.packet = packet;
+        }
+
+        public Packet<?> getPacket() {
+            return packet;
+        }
+    }
+    // Paper end
 }
diff --git a/src/main/java/net/minecraft/network/protocol/Packet.java b/src/main/java/net/minecraft/network/protocol/Packet.java
index cd4493a023748264748d4e892815f14d8a7bd7f6..0783b0777c8d7788bbf6780b464b709bf6dc2191 100644
--- a/src/main/java/net/minecraft/network/protocol/Packet.java
+++ b/src/main/java/net/minecraft/network/protocol/Packet.java
@@ -12,6 +12,12 @@ public interface Packet<T extends PacketListener> {
 
     void a(T t0);
 
+    // Paper start
+    default boolean packetTooLarge(NetworkManager manager) {
+        return false;
+    }
+    // Paper end
+
     default boolean a() {
         return false;
     }
diff --git a/src/main/java/net/minecraft/network/protocol/game/PacketPlayOutMapChunk.java b/src/main/java/net/minecraft/network/protocol/game/PacketPlayOutMapChunk.java
index 152118729b1a95dcae05d32aa4289034ba394226..0059ede4ba3ff271d47dd38ea87fddc2399aa008 100644
--- a/src/main/java/net/minecraft/network/protocol/game/PacketPlayOutMapChunk.java
+++ b/src/main/java/net/minecraft/network/protocol/game/PacketPlayOutMapChunk.java
@@ -91,7 +91,7 @@ public class PacketPlayOutMapChunk implements Packet<PacketListenerPlayOut> {
 
         int i = packetdataserializer.i();
 
-        if (i > 2097152) {
+        if (i > 2097152) { // Paper - if this changes, update PacketEncoder
             throw new RuntimeException("Chunk Packet trying to allocate too much memory on read.");
         } else {
             this.f = new byte[i];
diff --git a/src/main/java/net/minecraft/network/protocol/game/PacketPlayOutWindowItems.java b/src/main/java/net/minecraft/network/protocol/game/PacketPlayOutWindowItems.java
index b90e35a0099a2482f8fc2998bd079fc2fe6439e6..e540f95a370c627d3d81e0d3670049d01923559d 100644
--- a/src/main/java/net/minecraft/network/protocol/game/PacketPlayOutWindowItems.java
+++ b/src/main/java/net/minecraft/network/protocol/game/PacketPlayOutWindowItems.java
@@ -4,6 +4,7 @@ import java.io.IOException;
 import java.util.Iterator;
 import java.util.List;
 import net.minecraft.core.NonNullList;
+import net.minecraft.network.NetworkManager;
 import net.minecraft.network.PacketDataSerializer;
 import net.minecraft.network.protocol.Packet;
 import net.minecraft.world.item.ItemStack;
@@ -13,6 +14,15 @@ public class PacketPlayOutWindowItems implements Packet<PacketListenerPlayOut> {
     private int a;
     private List<ItemStack> b;
 
+    //Paper start
+    @Override
+    public boolean packetTooLarge(NetworkManager manager) {
+        for (int i = 0 ; i < this.b.size() ; i++) {
+            manager.sendPacket(new PacketPlayOutSetSlot(this.a, i, this.b.get(i)));
+        }
+        return true;
+    }
+    // Paper end
     public PacketPlayOutWindowItems() {}
 
     public PacketPlayOutWindowItems(int i, NonNullList<ItemStack> nonnulllist) {