PaperMC/patches/server/0283-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/Connection.java b/src/main/java/net/minecraft/network/Connection.java
index 7065d8e2b0782f1dbaf9932db9201b94ae455a31..f5106ed464d496420ac575b09d6c9a7dfeb87bec 100644
--- a/src/main/java/net/minecraft/network/Connection.java
+++ b/src/main/java/net/minecraft/network/Connection.java
@@ -158,6 +158,18 @@ public class Connection extends SimpleChannelInboundHandler<Packet<?>> {
     }
 
     public void exceptionCaught(ChannelHandlerContext channelhandlercontext, Throwable throwable) {
+        // Paper start
+        if (throwable instanceof io.netty.handler.codec.EncoderException && throwable.getCause() instanceof PacketEncoder.PacketTooLargeException packetTooLargeException) {
+            if (packetTooLargeException.getPacket().packetTooLarge(this)) {
+                return;
+            } else if (packetTooLargeException.getPacket().isSkippable()) {
+                Connection.LOGGER.debug("Skipping packet due to errors", throwable.getCause());
+                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 42828edf81bd475b673a9d143f79c0d0711f14f5..fbfadeb83719b81f42724e79c59e92ed88fdece7 100644
--- a/src/main/java/net/minecraft/network/PacketEncoder.java
+++ b/src/main/java/net/minecraft/network/PacketEncoder.java
@@ -40,7 +40,7 @@ public class PacketEncoder extends MessageToByteEncoder<Packet<?>> {
                     int j = friendlyByteBuf.writerIndex();
                     packet.write(friendlyByteBuf);
                     int k = friendlyByteBuf.writerIndex() - j;
-                    if (k > 8388608) {
+                    if (false && k > 8388608) { // Paper - disable
                         throw new IllegalArgumentException("Packet too big (is " + k + ", should be less than 8388608): " + packet);
                     } else {
                         int l = channelHandlerContext.channel().attr(Connection.ATTRIBUTE_PROTOCOL).get().getId();
@@ -54,7 +54,31 @@ public class PacketEncoder extends MessageToByteEncoder<Packet<?>> {
                         throw var10;
                     }
                 }
+
+                // Paper start
+                int packetLength = friendlyByteBuf.readableBytes();
+                if (packetLength > MAX_PACKET_SIZE) {
+                    throw new PacketTooLargeException(packet, packetLength);
+                }
+                // Paper end
             }
         }
     }
+
+    // Paper start
+    private static int MAX_PACKET_SIZE = 8388608;
+
+    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 10c1f2d8a92f848c3f2be9d1d06fd254978e6dcc..74bfe0d3942259c45702b099efdc4e101a4e3022 100644
--- a/src/main/java/net/minecraft/network/protocol/Packet.java
+++ b/src/main/java/net/minecraft/network/protocol/Packet.java
@@ -8,6 +8,12 @@ public interface Packet<T extends PacketListener> {
 
     void handle(T listener);
 
+    // Paper start
+    default boolean packetTooLarge(net.minecraft.network.Connection 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 0e076173033278587df2b5dfbd01cc9005651eb5..dbd8b9b09b82c1b75e8be9dc7416d9f0863c8c87 100644
--- a/src/main/java/net/minecraft/network/protocol/game/ClientboundContainerSetContentPacket.java
+++ b/src/main/java/net/minecraft/network/protocol/game/ClientboundContainerSetContentPacket.java
@@ -31,6 +31,16 @@ public class ClientboundContainerSetContentPacket implements Packet<ClientGamePa
         this.carriedItem = buf.readItem();
     }
 
+    // Paper start
+    @Override
+    public boolean packetTooLarge(net.minecraft.network.Connection manager) {
+        for (int i = 0 ; i < this.items.size() ; i++) {
+            manager.send(new ClientboundContainerSetSlotPacket(this.containerId, this.stateId, i, this.items.get(i)));
+        }
+        return true;
+    }
+    // Paper end
+
     @Override
     public void write(FriendlyByteBuf buf) {
         buf.writeByte(this.containerId);
diff --git a/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java b/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java
index 932cca4d957c1fc212b7a514ea23e8dc7ab5b9d9..f47eeb70661661610ef1a96dd9da67785825c126 100644
--- a/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java
+++ b/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java
@@ -50,7 +50,7 @@ public class ClientboundLevelChunkPacketData {
             throw new RuntimeException("Can't read heightmap in packet for [" + x + ", " + z + "]");
         } else {
             int i = buf.readVarInt();
-            if (i > 2097152) {
+            if (i > 2097152) { // Paper - diff on change - if this changes, update PacketEncoder
                 throw new RuntimeException("Chunk Packet trying to allocate too much memory on read.");
             } else {
                 this.buffer = new byte[i];