Fix up player info forwarding.

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/LoginSessionHandler.java

@@ -15,7 +15,6 @@ import com.velocitypowered.proxy.protocol.packet.*;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
-import io.netty.channel.ChannelPipeline;
 import net.kyori.text.TextComponent;
 
 import javax.crypto.Mac;
@@ -23,27 +22,16 @@ import javax.crypto.SecretKey;
 import javax.crypto.spec.SecretKeySpec;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
-import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.TimeUnit;
 
 public class LoginSessionHandler implements MinecraftSessionHandler {
     private final ServerConnection connection;
-    private ScheduledFuture<?> forwardingCheckTask;
+    private boolean informationForwarded;
 
     public LoginSessionHandler(ServerConnection connection) {
         this.connection = connection;
     }
 
-    @Override
-    public void activated() {
-        if (VelocityServer.getServer().getConfiguration().getPlayerInfoForwardingMode() == PlayerInfoForwarding.MODERN) {
-            forwardingCheckTask = connection.getMinecraftConnection().getChannel().eventLoop().schedule(() -> {
-                connection.getProxyPlayer().handleConnectionException(connection.getServerInfo(),
-                        TextComponent.of("Your server did not send the forwarding request in time. Is it set up correctly?"));
-            }, 1, TimeUnit.SECONDS);
-        }
-    }
-
     @Override
     public void handle(MinecraftPacket packet) {
         if (packet instanceof EncryptionRequest) {
@@ -60,11 +48,7 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
                         connection.getProxyPlayer().getRemoteAddress().getHostString(),
                         connection.getProxyPlayer().getProfile()));
                 connection.getMinecraftConnection().write(response);
-                cancelForwardingCheck();
+                informationForwarded = true;
-
-                ServerLogin login = new ServerLogin();
-                login.setUsername(connection.getProxyPlayer().getUsername());
-                connection.getMinecraftConnection().write(login);
             } else {
                 // Don't understand
                 LoginPluginResponse response = new LoginPluginResponse();
@@ -75,16 +59,21 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
             }
         } else if (packet instanceof Disconnect) {
             Disconnect disconnect = (Disconnect) packet;
-            connection.disconnect();
-
             // Do we have an outstanding notification? If so, fulfill it.
             doNotify(ConnectionRequestResults.forDisconnect(disconnect));
-
+            connection.disconnect();
-            connection.getProxyPlayer().handleConnectionException(connection.getServerInfo(), disconnect);
         } else if (packet instanceof SetCompression) {
             SetCompression sc = (SetCompression) packet;
             connection.getMinecraftConnection().setCompressionThreshold(sc.getThreshold());
         } else if (packet instanceof ServerLoginSuccess) {
+            if (VelocityServer.getServer().getConfiguration().getPlayerInfoForwardingMode() == PlayerInfoForwarding.MODERN &&
+                    !informationForwarded) {
+                doNotify(ConnectionRequestResults.forDisconnect(
+                        TextComponent.of("Your server did not send a forwarding request to the proxy. Is it set up correctly?")));
+                connection.disconnect();
+                return;
+            }
+
             // The player has been logged on to the backend server.
             connection.getMinecraftConnection().setState(StateRegistry.PLAY);
             ServerConnection existingConnection = connection.getProxyPlayer().getConnectedServer();
@@ -96,37 +85,26 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
                 existingConnection.disconnect();
             }
 
-            // Do we have an outstanding notification? If so, fulfill it.
             doNotify(ConnectionRequestResults.SUCCESSFUL);
-
             connection.getMinecraftConnection().setSessionHandler(new BackendPlaySessionHandler(connection));
             connection.getProxyPlayer().setConnectedServer(connection);
         }
     }
 
-    @Override
-    public void deactivated() {
-        cancelForwardingCheck();
-    }
-
     @Override
     public void exception(Throwable throwable) {
-        connection.getProxyPlayer().handleConnectionException(connection.getServerInfo(), throwable);
+        CompletableFuture<ConnectionRequestBuilder.Result> future = connection.getMinecraftConnection().getChannel()
+                .attr(ServerConnection.CONNECTION_NOTIFIER).getAndSet(null);
+        if (future != null) {
+            future.completeExceptionally(throwable);
+        }
     }
 
     private void doNotify(ConnectionRequestBuilder.Result result) {
-        ChannelPipeline pipeline = connection.getMinecraftConnection().getChannel().pipeline();
+        CompletableFuture<ConnectionRequestBuilder.Result> future = connection.getMinecraftConnection().getChannel()
-        ServerConnection.ConnectionNotifier n = pipeline.get(ServerConnection.ConnectionNotifier.class);
+                .attr(ServerConnection.CONNECTION_NOTIFIER).getAndSet(null);
-        if (n != null) {
+        if (future != null) {
-            n.getResult().complete(result);
+            future.complete(result);
-            pipeline.remove(ServerConnection.ConnectionNotifier.class);
-        }
-    }
-
-    private void cancelForwardingCheck() {
-        if (forwardingCheckTask != null) {
-            forwardingCheckTask.cancel(false);
-            forwardingCheckTask = null;
         }
     }
 

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/ServerConnection.java

@@ -18,6 +18,7 @@ import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import io.netty.channel.*;
 import io.netty.handler.timeout.ReadTimeoutHandler;
+import io.netty.util.AttributeKey;
 
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
@@ -31,7 +32,8 @@ import static com.velocitypowered.network.Connections.READ_TIMEOUT;
 import static com.velocitypowered.network.Connections.SERVER_READ_TIMEOUT_SECONDS;
 
 public class ServerConnection implements MinecraftConnectionAssociation {
-    static final String CONNECTION_NOTIFIER = "connection-notifier";
+    static final AttributeKey<CompletableFuture<ConnectionRequestBuilder.Result>> CONNECTION_NOTIFIER =
+            AttributeKey.newInstance("connection-notification-result");
 
     private final ServerInfo serverInfo;
     private final ConnectedPlayer proxyPlayer;
@@ -55,9 +57,9 @@ public class ServerConnection implements MinecraftConnectionAssociation {
                                 .addLast(FRAME_DECODER, new MinecraftVarintFrameDecoder())
                                 .addLast(FRAME_ENCODER, MinecraftVarintLengthEncoder.INSTANCE)
                                 .addLast(MINECRAFT_DECODER, new MinecraftDecoder(ProtocolConstants.Direction.CLIENTBOUND))
-                                .addLast(MINECRAFT_ENCODER, new MinecraftEncoder(ProtocolConstants.Direction.SERVERBOUND))
+                                .addLast(MINECRAFT_ENCODER, new MinecraftEncoder(ProtocolConstants.Direction.SERVERBOUND));
-                                .addLast(CONNECTION_NOTIFIER, new ConnectionNotifier(result));
 
+                        ch.attr(CONNECTION_NOTIFIER).set(result);
                         MinecraftConnection connection = new MinecraftConnection(ch);
                         connection.setState(StateRegistry.HANDSHAKE);
                         connection.setAssociation(ServerConnection.this);
@@ -111,13 +113,10 @@ public class ServerConnection implements MinecraftConnectionAssociation {
         minecraftConnection.setProtocolVersion(protocolVersion);
         minecraftConnection.setState(StateRegistry.LOGIN);
 
-        // Send the server login packet for <=1.12.2 and for 1.13+ servers not using "modern" forwarding.
-        if (protocolVersion <= ProtocolConstants.MINECRAFT_1_12_2 || forwardingMode != PlayerInfoForwarding.MODERN) {
         ServerLogin login = new ServerLogin();
         login.setUsername(proxyPlayer.getUsername());
         minecraftConnection.write(login);
     }
-    }
 
     public ConnectedPlayer getProxyPlayer() {
         return proxyPlayer;
@@ -140,25 +139,4 @@ public class ServerConnection implements MinecraftConnectionAssociation {
     public String toString() {
         return "[server connection] " + proxyPlayer.getProfile().getName() + " -> " + serverInfo.getName();
     }
-
-    static class ConnectionNotifier extends ChannelInboundHandlerAdapter {
-        private final CompletableFuture<ConnectionRequestBuilder.Result> result;
-
-        public ConnectionNotifier(CompletableFuture<ConnectionRequestBuilder.Result> result) {
-            this.result = result;
-        }
-
-        public CompletableFuture<ConnectionRequestBuilder.Result> getResult() {
-            return result;
-        }
-
-        public void onComplete() {
-            result.complete(ConnectionRequestResults.SUCCESSFUL);
-        }
-
-        @Override
-        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
-            result.completeExceptionally(cause);
-        }
-    }
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -247,7 +247,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
         @Override
         public void fireAndForget() {
             connect()
-                    .whenComplete((status, throwable) -> {
+                    .whenCompleteAsync((status, throwable) -> {
                         if (throwable != null) {
                             handleConnectionException(info, throwable);
                             return;
@@ -267,7 +267,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
                                 handleConnectionException(info, Disconnect.create(status.getReason().orElse(ConnectionMessages.INTERNAL_SERVER_CONNECTION_ERROR)));
                                 break;
                         }
-                    });
+                    }, connection.getChannel().eventLoop());
         }
     }
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/util/ConnectionRequestResults.java

@@ -3,6 +3,7 @@ package com.velocitypowered.proxy.connection.util;
 import com.velocitypowered.api.proxy.ConnectionRequestBuilder;
 import com.velocitypowered.proxy.protocol.packet.Disconnect;
 import net.kyori.text.Component;
+import net.kyori.text.TextComponent;
 import net.kyori.text.serializer.ComponentSerializers;
 
 import java.util.Optional;
@@ -42,4 +43,18 @@ public class ConnectionRequestResults {
             }
         };
     }
+
+    public static ConnectionRequestBuilder.Result forDisconnect(TextComponent component) {
+        return new ConnectionRequestBuilder.Result() {
+            @Override
+            public ConnectionRequestBuilder.Status getStatus() {
+                return ConnectionRequestBuilder.Status.SERVER_DISCONNECTED;
+            }
+
+            @Override
+            public Optional<Component> getReason() {
+                return Optional.of(component);
+            }
+        };
+    }
 }