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/Connection.java b/src/main/java/net/minecraft/network/Connection.java
index 7f4681910751047a26fdfc6b59bc460449c02001..35191d968fd30db16213540ef7121f4dede68e68 100644
--- a/src/main/java/net/minecraft/network/Connection.java
+++ b/src/main/java/net/minecraft/network/Connection.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 Connection 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 SkipPacketException) {
             Connection.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 d36d0424bcd4811af892f5f76fdcefda2af1ad33..a58c4fa8be7193b8acae5ea18a9780866312d768 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 29f10af7feabe2765f576586db4e3dba320dceda..9914a82ba0ec146ab13fe94c4dbf0ebf64926536 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 handle(T listener);
 
+    // Paper start
+    default boolean packetTooLarge(NetworkManager manager) {
+        return false;
+    }
+    // Paper end
+
     default boolean isSkippable() {
         return false;
     }
diff --git a/src/main/java/net/minecraft/network/protocol/game/ClientboundContainerSetContentPacket.java b/src/main/java/net/minecraft/network/protocol/game/ClientboundContainerSetContentPacket.java
index 70684318c562a9c3ce566b16cd0e68cfe95cbd50..64a15dcaef40c4e16458ab71d648f9fff169a3b2 100644
--- a/src/main/java/net/minecraft/network/protocol/game/ClientboundContainerSetContentPacket.java
+++ b/src/main/java/net/minecraft/network/protocol/game/ClientboundContainerSetContentPacket.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.Connection;
 import net.minecraft.network.FriendlyByteBuf;
 import net.minecraft.network.protocol.Packet;
 import net.minecraft.world.item.ItemStack;
@@ -13,6 +14,15 @@ public class ClientboundContainerSetContentPacket implements Packet<ClientGamePa
     private int containerId;
     private List<ItemStack> items;
 
+    //Paper start
+    @Override
+    public boolean packetTooLarge(Connection manager) {
+        for (int i = 0 ; i < this.items.size() ; i++) {
+            manager.send(new ClientboundContainerSetSlotPacket(this.containerId, i, this.items.get(i)));
+        }
+        return true;
+    }
+    // Paper end
     public ClientboundContainerSetContentPacket() {}
 
     public ClientboundContainerSetContentPacket(int syncId, NonNullList<ItemStack> contents) {
diff --git a/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacket.java b/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacket.java
index 4fe15aa331ca18319ca46d1b426f0d6fd24341f0..b7d303b5f51a35504888933efef74564fa01e59d 100644
--- a/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacket.java
+++ b/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacket.java
@@ -91,7 +91,7 @@ public class ClientboundLevelChunkPacket implements Packet<ClientGamePacketListe
 
         int i = buf.readVarInt();
 
-        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.buffer = new byte[i];