From f84a25850ddd3248c6fa8dad8a8d06612383dcf6 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sat, 2 Mar 2019 14:55:01 -0500
Subject: [PATCH] Handle Excessive Signs in Chunks creating too large of
 packets

Also adds a limit to stop sending Sign data to client after 500
signs per chunk to limit client lag.

Use -DPaper.excessiveSignsLimit=500 to configure that limit, or -1
to disable the limit and let your players be abused.

diff --git a/src/main/java/net/minecraft/server/NetworkManager.java b/src/main/java/net/minecraft/server/NetworkManager.java
index 23fcdea176..ba23d28335 100644
--- a/src/main/java/net/minecraft/server/NetworkManager.java
+++ b/src/main/java/net/minecraft/server/NetworkManager.java
@@ -220,6 +220,15 @@ public class NetworkManager extends SimpleChannelInboundHandler<Packet<?>> {
             });
         }
 
+        // Paper start
+        java.util.List<Packet> extraPackets = packet.getExtraPackets();
+        if (extraPackets != null && !extraPackets.isEmpty()) {
+            for (Packet extraPacket : extraPackets) {
+                this.dispatchPacket(extraPacket, genericfuturelistener);
+            }
+        }
+        // Paper end
+
     }
 
     private void sendPacketQueue() { this.o(); } // Paper - OBFHELPER
diff --git a/src/main/java/net/minecraft/server/Packet.java b/src/main/java/net/minecraft/server/Packet.java
index 2d8e6a2f4a..8d0965a053 100644
--- a/src/main/java/net/minecraft/server/Packet.java
+++ b/src/main/java/net/minecraft/server/Packet.java
@@ -11,6 +11,7 @@ public interface Packet<T extends PacketListener> {
     void a(T t0);
 
     // Paper start
+    default java.util.List<Packet> getExtraPackets() { return null; }
     default boolean packetTooLarge(NetworkManager manager) {
         return false;
     }
diff --git a/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java b/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java
index 58eccd9c63..ef71a1feb3 100644
--- a/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java
+++ b/src/main/java/net/minecraft/server/PacketPlayOutMapChunk.java
@@ -20,6 +20,15 @@ public class PacketPlayOutMapChunk implements Packet<PacketListenerPlayOut> {
 
     public PacketPlayOutMapChunk() {}
 
+    // Paper start
+    private final java.util.List<Packet> extraPackets = new java.util.ArrayList<>();
+    private static final int SKIP_EXCESSIVE_SIGNS_LIMIT = Integer.getInteger("Paper.excessiveSignsLimit", 500);
+
+    @Override
+    public java.util.List<Packet> getExtraPackets() {
+        return extraPackets;
+    }
+    // Paper end
     public PacketPlayOutMapChunk(Chunk chunk, int i) {
         ChunkCoordIntPair chunkcoordintpair = chunk.getPos();
 
@@ -42,6 +51,7 @@ public class PacketPlayOutMapChunk implements Packet<PacketListenerPlayOut> {
         this.c = this.a(new PacketDataSerializer(this.i()), chunk, i);
         this.f = Lists.newArrayList();
         iterator = chunk.getTileEntities().entrySet().iterator();
+        int totalSigns = 0; // Paper
 
         while (iterator.hasNext()) {
             entry = (Entry) iterator.next();
@@ -50,6 +60,14 @@ public class PacketPlayOutMapChunk implements Packet<PacketListenerPlayOut> {
             int j = blockposition.getY() >> 4;
 
             if (this.f() || (i & 1 << j) != 0) {
+                // Paper start - send signs separately
+                if (tileentity instanceof TileEntitySign) {
+                    if (SKIP_EXCESSIVE_SIGNS_LIMIT < 0 || ++totalSigns < SKIP_EXCESSIVE_SIGNS_LIMIT) {
+                        this.extraPackets.add(tileentity.getUpdatePacket());
+                    }
+                    continue;
+                }
+                // Paper end
                 NBTTagCompound nbttagcompound = tileentity.b();
                 if (tileentity instanceof TileEntitySkull) { TileEntitySkull.sanitizeTileEntityUUID(nbttagcompound); } // Paper
 
-- 
2.21.0