Paper/CraftBukkit-Patches/0137-Fix-race-condition-that-could-kill-connections-befor.patch

From ea2b784ee80f96adc590a68530786ab433efdb55 Mon Sep 17 00:00:00 2001
From: Jonas Konrad <me@yawk.at>
Date: Fri, 25 Apr 2014 23:46:46 +0200
Subject: [PATCH] Fix race condition that could kill connections before they
 were initiated

Because NetworkManagers are registered before they get their channel in
channelActive, the ServerConnection would remove them sometimes because
it thought they were disconnected. This commit fixes this by introducing
a 'preparing' variable that is true while the NetworkManager is not
initialized. The ServerConnection does not remove NetworkManagers with
this flag.

diff --git a/src/main/java/net/minecraft/server/NetworkManager.java b/src/main/java/net/minecraft/server/NetworkManager.java
index 9939652..ae3de2f 100644
--- a/src/main/java/net/minecraft/server/NetworkManager.java
+++ b/src/main/java/net/minecraft/server/NetworkManager.java
@@ -45,6 +45,7 @@ public class NetworkManager extends SimpleChannelInboundHandler {
     public SocketAddress n;
     public java.util.UUID spoofedUUID;
     public Property[] spoofedProfile;
+    public boolean preparing = true;
     // Spigot End
     private PacketListener o;
     private EnumProtocol p;
@@ -73,6 +74,9 @@ public class NetworkManager extends SimpleChannelInboundHandler {
         super.channelActive(channelhandlercontext);
         this.m = channelhandlercontext.channel();
         this.n = this.m.remoteAddress();
+        // Spigot Start
+        this.preparing = false;
+        // Spigot End
         this.a(EnumProtocol.HANDSHAKING);
     }
 
@@ -191,6 +195,9 @@ public class NetworkManager extends SimpleChannelInboundHandler {
     }
 
     public void close(IChatBaseComponent ichatbasecomponent) {
+        // Spigot Start
+        this.preparing = false;
+        // Spigot End
         if (this.m.isOpen()) {
             this.m.close();
             this.q = ichatbasecomponent;
diff --git a/src/main/java/net/minecraft/server/ServerConnection.java b/src/main/java/net/minecraft/server/ServerConnection.java
index 1d7b814..981e22c 100644
--- a/src/main/java/net/minecraft/server/ServerConnection.java
+++ b/src/main/java/net/minecraft/server/ServerConnection.java
@@ -66,6 +66,10 @@ public class ServerConnection {
                 NetworkManager networkmanager = (NetworkManager) iterator.next();
 
                 if (!networkmanager.isConnected()) {
+                    // Spigot Start
+                    // Fix a race condition where a NetworkManager could be unregistered just before connection.
+                    if (networkmanager.preparing) continue;
+                    // Spigot End
                     iterator.remove();
                     if (networkmanager.f() != null) {
                         networkmanager.getPacketListener().a(networkmanager.f());
-- 
1.9.1