From bf31dfa1560b2be03d92ec8ecda481ce108d49d1 Mon Sep 17 00:00:00 2001
From: Tux <write@imaginarycode.com>
Date: Wed, 21 Dec 2016 03:13:03 -0500
Subject: [PATCH] Use async Netty DNS resolver

We no longer need to cache the address for the session server now.

diff --git a/proxy/pom.xml b/proxy/pom.xml
index 1220a41..5d105b0 100644
--- a/proxy/pom.xml
+++ b/proxy/pom.xml
@@ -25,6 +25,14 @@
             <version>${netty.version}</version>
             <scope>compile</scope>
         </dependency>
+        <!-- Waterfall Start - add Netty DNS resolver -->
+        <dependency>
+            <groupId>io.netty</groupId>
+            <artifactId>netty-resolver-dns</artifactId>
+            <version>${netty.version}</version>
+            <scope>compile</scope>
+        </dependency>
+        <!-- Waterfall End -->
         <dependency>
             <groupId>io.netty</groupId>
             <artifactId>netty-handler</artifactId>
diff --git a/proxy/src/main/java/net/md_5/bungee/http/HttpClient.java b/proxy/src/main/java/net/md_5/bungee/http/HttpClient.java
index 2feb4d6..7e381f5 100644
--- a/proxy/src/main/java/net/md_5/bungee/http/HttpClient.java
+++ b/proxy/src/main/java/net/md_5/bungee/http/HttpClient.java
@@ -27,7 +27,11 @@ public class HttpClient
 {
 
     public static final int TIMEOUT = 5000;
-    private static final Cache<String, InetAddress> addressCache = CacheBuilder.newBuilder().expireAfterWrite( 1, TimeUnit.MINUTES ).build();
+    // Waterfall Start - use async resolver from Netty
+    //private static final Cache<String, InetAddress> addressCache = CacheBuilder.newBuilder().expireAfterWrite( 1, TimeUnit.MINUTES ).build(); // Waterfall - remove cache
+    private static final io.netty.resolver.dns.DnsAddressResolverGroup dnsResolverGroup =
+            new io.netty.resolver.dns.DnsAddressResolverGroup(PipelineUtils.getDatagramChannel(), io.netty.resolver.dns.DnsServerAddresses.defaultAddresses());
+    // Waterfall End
 
     @SuppressWarnings("UnusedAssignment")
     public static void get(String url, EventLoop eventLoop, final Callback<String> callback)
@@ -57,19 +61,22 @@ public class HttpClient
             }
         }
 
-        InetAddress inetHost = addressCache.getIfPresent( uri.getHost() );
-        if ( inetHost == null )
-        {
-            try
-            {
-                inetHost = InetAddress.getByName( uri.getHost() );
-            } catch ( UnknownHostException ex )
-            {
-                callback.done( null, ex );
-                return;
-            }
-            addressCache.put( uri.getHost(), inetHost );
-        }
+        // Waterfall Start: remove IP address cache
+        //InetAddress inetHost = addressCache.getIfPresent( uri.getHost() );
+        //if ( inetHost == null )
+        //{
+        //    try
+        //    {
+        //        inetHost = InetAddress.getByName( uri.getHost() );
+        //    } catch ( UnknownHostException ex )
+        //    {
+        //        callback.done( null, ex );
+        //        return;
+        //    }
+        //    addressCache.put( uri.getHost(), inetHost );
+        //}
+        java.net.InetSocketAddress address = java.net.InetSocketAddress.createUnresolved(uri.getHost(), port);
+        // Waterfall End
 
         ChannelFutureListener future = new ChannelFutureListener()
         {
@@ -86,13 +93,13 @@ public class HttpClient
                     future.channel().writeAndFlush( request );
                 } else
                 {
-                    addressCache.invalidate( uri.getHost() );
+                    // addressCache.invalidate( uri.getHost() ); // Waterfall - use async DNS resolver
                     callback.done( null, future.cause() );
                 }
             }
         };
 
         new Bootstrap().channel( PipelineUtils.getChannel() ).group( eventLoop ).handler( new HttpInitializer( callback, ssl, uri.getHost(), port ) ).
-                option( ChannelOption.CONNECT_TIMEOUT_MILLIS, TIMEOUT ).remoteAddress( inetHost, port ).connect().addListener( future );
+                option( ChannelOption.CONNECT_TIMEOUT_MILLIS, TIMEOUT ).resolver(dnsResolverGroup).remoteAddress( address ).connect().addListener( future ); // Waterfall - use async DNS resolver
     }
 }
diff --git a/proxy/src/main/java/net/md_5/bungee/netty/PipelineUtils.java b/proxy/src/main/java/net/md_5/bungee/netty/PipelineUtils.java
index f6a10e7..ddf598e 100644
--- a/proxy/src/main/java/net/md_5/bungee/netty/PipelineUtils.java
+++ b/proxy/src/main/java/net/md_5/bungee/netty/PipelineUtils.java
@@ -103,7 +103,7 @@ public class PipelineUtils
         return epoll ? EpollSocketChannel.class : NioSocketChannel.class;
     }
 
-    public static Class<? extends Channel> getDatagramChannel()
+    public static Class<? extends io.netty.channel.socket.DatagramChannel> getDatagramChannel() // Waterfall - change to DatagramChannel
     {
         return epoll ? EpollDatagramChannel.class : NioDatagramChannel.class;
     }
-- 
2.7.4