GH-3509: Fix Memory Leak with Intercepted TCP Conn

Resolves https://github.com/spring-projects/spring-integration/issues/3509

When a connection was intercepted, the `TcpSender.add...` was called with the
interceptor, but the `removeDead...` was called with the actual connection,
causing a memory leak.

Always call the `TcpSender` with the outer-most interceptor.

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/AbstractConnectionFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -615,12 +615,13 @@ public abstract class AbstractConnectionFactory extends IntegrationObjectSupport
 				if (this.senders.size() == 0) {
 					connection.registerSender(wrapper);
 				}
+				connection.setWrapped(true);
 				connection = wrapper;
 			}
 			return connection;
 		}
 		finally {
-			this.addConnection(connection);
+			addConnection(connection);
 		}
 	}
 

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpConnectionInterceptorFactoryChain.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,6 +22,7 @@ import org.springframework.lang.Nullable;
 
 /**
  * @author Gary Russell
+ * @author Artem Bilan
  * @since 2.0
  *
  */
@@ -38,4 +39,8 @@ public class TcpConnectionInterceptorFactoryChain {
 		this.interceptorFactories = Arrays.copyOf(interceptorFactories, interceptorFactories.length);
 	}
 
+	public void setInterceptor(TcpConnectionInterceptorFactory... interceptorFactories) {
+		this.interceptorFactories = Arrays.copyOf(interceptorFactories, interceptorFactories.length);
+	}
+
 }

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpConnectionSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2001-2020 the original author or authors.
+ * Copyright 2001-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -96,6 +96,8 @@ public abstract class TcpConnectionSupport implements TcpConnection {
 
 	private boolean manualListenerRegistration;
 
+	private boolean wrapped;
+
 	/*
 	 * This boolean is to avoid looking for a temporary listener when not needed
 	 * to avoid a CPU cache flush. This does not have to be volatile because it
@@ -164,8 +166,10 @@ public abstract class TcpConnectionSupport implements TcpConnection {
 	 */
 	@Override
 	public void close() {
-		for (TcpSender sender : this.senders) {
-			sender.removeDeadConnection(this);
+		if (!this.wrapped) {
+			for (TcpSender sender : this.senders) {
+				sender.removeDeadConnection(this);
+			}
 		}
 		// close() may be called multiple times; only publish once
 		if (!this.closePublished.getAndSet(true)) {
@@ -194,6 +198,9 @@ public abstract class TcpConnectionSupport implements TcpConnection {
 				outerListener = nextListener;
 			}
 			outerListener.close();
+			for (TcpSender sender : getSenders()) {
+				sender.removeDeadConnection(outerListener);
+			}
 			if (isException) {
 				// ensure physical close in case the interceptor did not close
 				this.close();
@@ -264,6 +271,10 @@ public abstract class TcpConnectionSupport implements TcpConnection {
 		this.needsTest = needsTest;
 	}
 
+	void setSenders(List<TcpSender> senders) {
+		this.senders.addAll(senders);
+	}
+
 	/**
 	 * Set the listener that will receive incoming Messages.
 	 * @param listener The listener.
@@ -401,6 +412,14 @@ public abstract class TcpConnectionSupport implements TcpConnection {
 		return this.socketInfo;
 	}
 
+	/**
+	 * Set to true if intercepted.
+	 * @param wrapped true if wrapped.
+	 */
+	public void setWrapped(boolean wrapped) {
+		this.wrapped = wrapped;
+	}
+
 	public String getConnectionFactoryName() {
 		return this.connectionFactoryName;
 	}

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNetClientConnectionFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -56,7 +56,11 @@ public class TcpNetClientConnectionFactory extends
 			TcpConnectionSupport connection =
 					this.tcpNetConnectionSupport.createNewConnection(socket, false, isLookupHost(),
 					getApplicationEventPublisher(), getComponentName());
-			connection = wrapConnection(connection);
+			TcpConnectionSupport wrapped = wrapConnection(connection);
+			if (wrapped.equals(connection)) {
+				connection.setSenders(getSenders());
+				connection = wrapped;
+			}
 			initializeConnection(connection, socket);
 			this.getTaskExecutor().execute(connection);
 			this.harvestClosedConnections();

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNetServerConnectionFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -143,7 +143,11 @@ public class TcpNetServerConnectionFactory extends AbstractServerConnectionFacto
 						setSocketAttributes(socket);
 						TcpConnectionSupport connection = this.tcpNetConnectionSupport.createNewConnection(socket, true,
 								isLookupHost(), getApplicationEventPublisher(), getComponentName());
-						connection = wrapConnection(connection);
+						TcpConnectionSupport wrapped = wrapConnection(connection);
+						if (!wrapped.equals(connection)) {
+							connection.setSenders(getSenders());
+							connection = wrapped;
+						}
 						initializeConnection(connection, socket);
 						getTaskExecutor().execute(connection);
 						harvestClosedConnections();

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNioClientConnectionFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -98,6 +98,9 @@ public class TcpNioClientConnectionFactory extends
 				((TcpNioSSLConnection) connection).setHandshakeTimeout(sslHandshakeTimeout);
 			}
 			TcpConnectionSupport wrappedConnection = wrapConnection(connection);
+			if (!wrappedConnection.equals(connection)) {
+				connection.setSenders(getSenders());
+			}
 			initializeConnection(wrappedConnection, socketChannel.socket());
 			if (getSoTimeout() > 0) {
 				connection.setLastRead(System.currentTimeMillis());

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNioServerConnectionFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -277,6 +277,9 @@ public class TcpNioServerConnectionFactory extends AbstractServerConnectionFacto
 					isLookupHost(), getApplicationEventPublisher(), getComponentName());
 			connection.setUsingDirectBuffers(this.usingDirectBuffers);
 			TcpConnectionSupport wrappedConnection = wrapConnection(connection);
+			if (!wrappedConnection.equals(connection)) {
+				connection.setSenders(getSenders());
+			}
 			initializeConnection(wrappedConnection, socketChannel.socket());
 			return connection;
 		}

spring-integration-ip/src/test/java/org/springframework/integration/ip/tcp/AbstractTcpChannelAdapterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2019 the original author or authors.
+ * Copyright 2013-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,34 +16,29 @@
 
 package org.springframework.integration.ip.tcp;
 
-import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.integration.ip.tcp.connection.AbstractConnectionFactory;
 import org.springframework.integration.ip.tcp.connection.HelloWorldInterceptorFactory;
 
 /**
  * @author Gary Russell
+ * @author Mário Dias
+ * @author Artem Bilan
+ *
  * @since 3.0
  *
  */
 public class AbstractTcpChannelAdapterTests {
 
-	private static final ApplicationEventPublisher NOOP_PUBLISHER = new ApplicationEventPublisher() {
-
-		@Override
-		public void publishEvent(ApplicationEvent event) {
-		}
-
-		@Override
-		public void publishEvent(Object event) {
-
-		}
-
-	};
+	private static final ApplicationEventPublisher NOOP_PUBLISHER = event -> { };
 
 	protected HelloWorldInterceptorFactory newInterceptorFactory() {
+		return newInterceptorFactory(NOOP_PUBLISHER);
+	}
+
+	protected HelloWorldInterceptorFactory newInterceptorFactory(ApplicationEventPublisher applicationEventPublisher) {
 		HelloWorldInterceptorFactory factory = new HelloWorldInterceptorFactory();
-		factory.setApplicationEventPublisher(NOOP_PUBLISHER);
+		factory.setApplicationEventPublisher(applicationEventPublisher);
 		return factory;
 	}
 
@@ -51,5 +46,4 @@ public class AbstractTcpChannelAdapterTests {
 		connectionFactory.setApplicationEventPublisher(NOOP_PUBLISHER);
 	}
 
-
 }

spring-integration-ip/src/test/java/org/springframework/integration/ip/tcp/TcpSendingMessageHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,6 +30,7 @@ import java.net.SocketException;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.TreeSet;
 import java.util.concurrent.CountDownLatch;
@@ -39,6 +40,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 
 import javax.net.ServerSocketFactory;
+import javax.net.SocketFactory;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -57,15 +59,21 @@ import org.springframework.integration.config.ConsumerEndpointFactoryBean;
 import org.springframework.integration.ip.tcp.connection.AbstractClientConnectionFactory;
 import org.springframework.integration.ip.tcp.connection.AbstractConnectionFactory;
 import org.springframework.integration.ip.tcp.connection.AbstractServerConnectionFactory;
+import org.springframework.integration.ip.tcp.connection.HelloWorldInterceptor;
+import org.springframework.integration.ip.tcp.connection.TcpConnection;
+import org.springframework.integration.ip.tcp.connection.TcpConnectionCloseEvent;
 import org.springframework.integration.ip.tcp.connection.TcpConnectionInterceptorFactory;
 import org.springframework.integration.ip.tcp.connection.TcpConnectionInterceptorFactoryChain;
+import org.springframework.integration.ip.tcp.connection.TcpConnectionOpenEvent;
 import org.springframework.integration.ip.tcp.connection.TcpNetClientConnectionFactory;
+import org.springframework.integration.ip.tcp.connection.TcpNetServerConnectionFactory;
 import org.springframework.integration.ip.tcp.connection.TcpNioClientConnectionFactory;
 import org.springframework.integration.ip.tcp.serializer.ByteArrayCrLfSerializer;
 import org.springframework.integration.ip.tcp.serializer.ByteArrayLengthHeaderSerializer;
 import org.springframework.integration.ip.tcp.serializer.ByteArrayStxEtxSerializer;
 import org.springframework.integration.ip.util.TestingUtilities;
 import org.springframework.integration.support.MessageBuilder;
+import org.springframework.integration.test.util.TestUtils;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageChannel;
 import org.springframework.messaging.MessagingException;
@@ -77,6 +85,7 @@ import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
 /**
  * @author Gary Russell
  * @author Artem Bilan
+ * @author Mário Dias
  *
  * @since 2.0
  */
@@ -84,7 +93,7 @@ public class TcpSendingMessageHandlerTests extends AbstractTcpChannelAdapterTest
 
 	private static final Log logger = LogFactory.getLog(TcpSendingMessageHandlerTests.class);
 
-	private AsyncTaskExecutor executor = new SimpleAsyncTaskExecutor();
+	private final AsyncTaskExecutor executor = new SimpleAsyncTaskExecutor();
 
 	private void readFully(InputStream is, byte[] buff) throws IOException {
 		for (int i = 0; i < buff.length; i++) {
@@ -1191,4 +1200,67 @@ public class TcpSendingMessageHandlerTests extends AbstractTcpChannelAdapterTest
 		}
 	}
 
+	@SuppressWarnings("unchecked")
+	@Test
+	public void testInterceptedConnection() throws Exception {
+		final CountDownLatch latch = new CountDownLatch(1);
+		AbstractServerConnectionFactory scf = new TcpNetServerConnectionFactory(0);
+		ByteArrayCrLfSerializer serializer = new ByteArrayCrLfSerializer();
+		scf.setSerializer(serializer);
+		scf.setDeserializer(serializer);
+		TcpReceivingChannelAdapter adapter = new TcpReceivingChannelAdapter();
+		adapter.setConnectionFactory(scf);
+		TcpSendingMessageHandler handler = new TcpSendingMessageHandler();
+		handler.setConnectionFactory(scf);
+		final AtomicReference<TcpConnection> connection = new AtomicReference<>();
+		scf.setApplicationEventPublisher(event -> {
+			if (event instanceof TcpConnectionOpenEvent) {
+				connection.set(handler.getConnections()
+						.get(((TcpConnectionOpenEvent) event).getConnectionId()));
+				latch.countDown();
+			}
+		});
+		TcpConnectionInterceptorFactoryChain fc = new TcpConnectionInterceptorFactoryChain();
+		fc.setInterceptor(newInterceptorFactory(scf.getApplicationEventPublisher()));
+		scf.setInterceptorFactoryChain(fc);
+		scf.start();
+		TestingUtilities.waitListening(scf, null);
+		int port = scf.getPort();
+		Socket socket = SocketFactory.getDefault().createSocket("localhost", port);
+		socket.close();
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(connection.get()).isInstanceOf(HelloWorldInterceptor.class);
+		assertThat(TestUtils.getPropertyValue(handler, "connections", Map.class)).isEmpty();
+		scf.stop();
+	}
+
+	@Test
+	public void testInterceptedCleanup() throws Exception {
+		final CountDownLatch latch = new CountDownLatch(1);
+		AbstractServerConnectionFactory scf = new TcpNetServerConnectionFactory(0);
+		ByteArrayCrLfSerializer serializer = new ByteArrayCrLfSerializer();
+		scf.setSerializer(serializer);
+		scf.setDeserializer(serializer);
+		TcpReceivingChannelAdapter adapter = new TcpReceivingChannelAdapter();
+		adapter.setConnectionFactory(scf);
+		TcpSendingMessageHandler handler = new TcpSendingMessageHandler();
+		handler.setConnectionFactory(scf);
+		scf.setApplicationEventPublisher(event -> {
+			if (event instanceof TcpConnectionCloseEvent) {
+				latch.countDown();
+			}
+		});
+		TcpConnectionInterceptorFactoryChain fc = new TcpConnectionInterceptorFactoryChain();
+		fc.setInterceptor(newInterceptorFactory(scf.getApplicationEventPublisher()));
+		scf.setInterceptorFactoryChain(fc);
+		scf.start();
+		TestingUtilities.waitListening(scf, null);
+		int port = scf.getPort();
+		Socket socket = SocketFactory.getDefault().createSocket("localhost", port);
+		socket.close();
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(handler.getConnections().isEmpty()).isTrue();
+		scf.stop();
+	}
+
 }