From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Andrew Steinborn <git@steinborn.me>
Date: Sun, 5 Jul 2020 22:38:18 -0400
Subject: [PATCH] Optimize NetworkManager Exception Handling


diff --git a/src/main/java/net/minecraft/network/ConnectionProtocol.java b/src/main/java/net/minecraft/network/ConnectionProtocol.java
index a30fa3d54b70ab63d24dd67a69f39742335aff1e..a79da4bc0ed06ff8ede0a34f00194f927251099b 100644
--- a/src/main/java/net/minecraft/network/ConnectionProtocol.java
+++ b/src/main/java/net/minecraft/network/ConnectionProtocol.java
@@ -329,6 +329,7 @@ public enum ConnectionProtocol implements BundlerInfo.Provider {
 
         @Nullable
         public Packet<?> createPacket(int id, FriendlyByteBuf buf) {
+            if (id < 0 || id >= this.idToDeserializer.size()) return null; // Paper
             Function<FriendlyByteBuf, ? extends Packet<T>> function = this.idToDeserializer.get(id);
             return function != null ? function.apply(buf) : null;
         }
diff --git a/src/main/java/net/minecraft/network/Varint21FrameDecoder.java b/src/main/java/net/minecraft/network/Varint21FrameDecoder.java
index 99b581052f937b0f2d6b5d73de699008c1d51774..81ec2011a93bb94200ad750f4666ba1cd8be11c5 100644
--- a/src/main/java/net/minecraft/network/Varint21FrameDecoder.java
+++ b/src/main/java/net/minecraft/network/Varint21FrameDecoder.java
@@ -8,9 +8,20 @@ import io.netty.handler.codec.CorruptedFrameException;
 import java.util.List;
 
 public class Varint21FrameDecoder extends ByteToMessageDecoder {
+    private final byte[] lenBuf = new byte[3]; // Paper
+    @Override
     protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> list) {
+        // Paper start - if channel is not active just discard the packet
+        if (!channelHandlerContext.channel().isActive()) {
+            byteBuf.skipBytes(byteBuf.readableBytes());
+            return;
+        }
+        // Paper end
         byteBuf.markReaderIndex();
-        byte[] bs = new byte[3];
+        // Paper start - reuse temporary length buffer
+        byte[] bs = lenBuf;
+        java.util.Arrays.fill(bs, (byte) 0);
+        // Paper end
 
         for(int i = 0; i < bs.length; ++i) {
             if (!byteBuf.isReadable()) {