It looks like the NIO network handler works now - some testing needed to see how reliably

core/src/main/java/ch/dissem/bitmessage/factory/V3MessageReader.java

@@ -21,17 +21,13 @@ import ch.dissem.bitmessage.entity.NetworkMessage;
 import ch.dissem.bitmessage.exception.ApplicationException;
 import ch.dissem.bitmessage.exception.NodeException;
 import ch.dissem.bitmessage.utils.Decode;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.io.ByteArrayInputStream;
-import java.io.FileWriter;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.nio.ByteBuffer;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.UUID;
 
 import static ch.dissem.bitmessage.entity.NetworkMessage.MAGIC_BYTES;
 import static ch.dissem.bitmessage.factory.BufferPool.bufferPool;
@@ -42,8 +38,6 @@ import static ch.dissem.bitmessage.utils.Singleton.cryptography;
  * Similar to the {@link V3MessageFactory}, but used for NIO buffers which may or may not contain a whole message.
  */
 public class V3MessageReader {
-    private static final Logger LOG = LoggerFactory.getLogger(V3MessageReader.class);
-
     private ByteBuffer headerBuffer;
     private ByteBuffer dataBuffer;
 
@@ -53,7 +47,6 @@ public class V3MessageReader {
     private byte[] checksum;
 
     private List<NetworkMessage> messages = new LinkedList<>();
-    private SizeInfo sizeInfo = new SizeInfo();
 
     public ByteBuffer getActiveBuffer() {
         if (state != null && state != ReaderState.DATA) {
@@ -88,7 +81,6 @@ public class V3MessageReader {
                     throw new NodeException("Payload of " + length + " bytes received, no more than " +
                         MAX_PAYLOAD_SIZE + " was expected.");
                 }
-                sizeInfo.add(length); // FIXME: remove this once we have some values to work with
                 checksum = new byte[4];
                 headerBuffer.get(checksum);
                 state = ReaderState.DATA;
@@ -194,37 +186,4 @@ public class V3MessageReader {
     }
 
     private enum ReaderState {MAGIC, HEADER, DATA}
-
-    private class SizeInfo {
-        private FileWriter file;
-        private long min = Long.MAX_VALUE;
-        private long avg = 0;
-        private long max = Long.MIN_VALUE;
-        private long count = 0;
-
-        private SizeInfo() {
-            try {
-                file = new FileWriter("D:/message_size_info-" + UUID.randomUUID() + ".csv");
-            } catch (IOException e) {
-                LOG.error(e.getMessage(), e);
-            }
-        }
-
-        private void add(long length) {
-            avg = (count * avg + length) / (count + 1);
-            if (length < min) {
-                min = length;
-            }
-            if (length > max) {
-                max = length;
-            }
-            count++;
-            LOG.info("Received message with data size " + length + "; Min: " + min + "; Max: " + max + "; Avg: " + avg);
-            try {
-                file.write(length + "\n");
-            } catch (IOException e) {
-                e.printStackTrace();
-            }
-        }
-    }
 }

networking/src/main/java/ch/dissem/bitmessage/networking/AbstractConnection.java

@@ -228,10 +228,11 @@ public abstract class AbstractConnection {
                 break;
             case CUSTOM:
                 MessagePayload response = ctx.getCustomCommandHandler().handle((CustomMessage) payload);
-                if (response != null) {
+                if (response == null) {
+                    disconnect();
+                } else {
                     send(response);
                 }
-                disconnect();
                 break;
             default:
                 throw new NodeException("Command 'version' or 'verack' expected, but was '"

networking/src/main/java/ch/dissem/bitmessage/networking/nio/ConnectionInfo.java

@@ -17,10 +17,7 @@
 package ch.dissem.bitmessage.networking.nio;
 
 import ch.dissem.bitmessage.InternalContext;
-import ch.dissem.bitmessage.entity.GetData;
+import ch.dissem.bitmessage.entity.*;
-import ch.dissem.bitmessage.entity.MessagePayload;
-import ch.dissem.bitmessage.entity.NetworkMessage;
-import ch.dissem.bitmessage.entity.Version;
 import ch.dissem.bitmessage.entity.valueobject.InventoryVector;
 import ch.dissem.bitmessage.entity.valueobject.NetworkAddress;
 import ch.dissem.bitmessage.exception.NodeException;
@@ -112,16 +109,18 @@ public class ConnectionInfo extends AbstractConnection {
 
     public void updateSyncStatus() {
         if (!syncFinished) {
-            syncFinished = reader.getMessages().isEmpty() && syncFinished(null);
+            syncFinished = (reader == null || reader.getMessages().isEmpty()) && syncFinished(null);
         }
     }
 
     public boolean isExpired() {
         switch (state) {
             case CONNECTING:
-                return lastUpdate < System.currentTimeMillis() - 30000;
+                // the TCP timeout starts out at 20 seconds
+                return lastUpdate < System.currentTimeMillis() - 20_000;
             case ACTIVE:
-                return lastUpdate < System.currentTimeMillis() - 30000;
+                // after verack messages are exchanged, the timeout is raised to 10 minutes
+                return lastUpdate < System.currentTimeMillis() - 600_000;
             case DISCONNECTED:
                 return true;
             default:
@@ -150,4 +149,10 @@ public class ConnectionInfo extends AbstractConnection {
             commonRequestedObjects.addAll(((GetData) payload).getInventory());
         }
     }
+
+    public boolean isWritePending() {
+        return !sendingQueue.isEmpty()
+            || headerOut != null && headerOut.hasRemaining()
+            || payloadOut != null && payloadOut.hasRemaining();
+    }
 }

networking/src/main/java/ch/dissem/bitmessage/networking/nio/NioNetworkHandler.java

@@ -64,7 +64,7 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
     private Selector selector;
     private ServerSocketChannel serverChannel;
     private Map<ConnectionInfo, SelectionKey> connections = new ConcurrentHashMap<>();
-    private int requestedObjectsCount;
+    private volatile int requestedObjectsCount;
 
     private Thread starter;
 
@@ -94,13 +94,15 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
     public CustomMessage send(InetAddress server, int port, CustomMessage request) {
         try (SocketChannel channel = SocketChannel.open(new InetSocketAddress(server, port))) {
             channel.configureBlocking(true);
-            ByteBuffer buffer = ByteBuffer.allocate(MAX_MESSAGE_SIZE);
+            ByteBuffer headerBuffer = ByteBuffer.allocate(HEADER_SIZE);
-            new NetworkMessage(request).write(buffer);
+            ByteBuffer payloadBuffer = new NetworkMessage(request).writeHeaderAndGetPayloadBuffer(headerBuffer);
-            buffer.flip();
+            headerBuffer.flip();
-            while (buffer.hasRemaining()) {
+            while (headerBuffer.hasRemaining()) {
-                channel.write(buffer);
+                channel.write(headerBuffer);
+            }
+            while (payloadBuffer.hasRemaining()) {
+                channel.write(payloadBuffer);
             }
-            buffer.clear();
 
             V3MessageReader reader = new V3MessageReader();
             while (channel.isConnected() && reader.getMessages().isEmpty()) {
@@ -195,11 +197,25 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
                     if (missing > 0) {
                         List<NetworkAddress> addresses = ctx.getNodeRegistry().getKnownAddresses(missing, ctx.getStreams());
                         for (NetworkAddress address : addresses) {
+                            if (isConnectedTo(address)) {
+                                continue;
+                            }
                             try {
                                 SocketChannel channel = SocketChannel.open();
                                 channel.configureBlocking(false);
                                 channel.connect(new InetSocketAddress(address.toInetAddress(), address.getPort()));
-                                channel.finishConnect();
+                                long timeout = System.currentTimeMillis() + 20_000;
+                                while (!channel.finishConnect() && System.currentTimeMillis() < timeout) {
+                                    try {
+                                        Thread.sleep(100);
+                                    } catch (InterruptedException e) {
+                                        break;
+                                    }
+                                }
+                                if (!channel.finishConnect()) {
+                                    channel.close();
+                                    continue;
+                                }
                                 ConnectionInfo connection = new ConnectionInfo(ctx, CLIENT,
                                     address,
                                     listener,
@@ -248,6 +264,7 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
                         Iterator<SelectionKey> keyIterator = selector.selectedKeys().iterator();
                         while (keyIterator.hasNext()) {
                             SelectionKey key = keyIterator.next();
+                            keyIterator.remove();
                             if (key.attachment() instanceof ConnectionInfo) {
                                 SocketChannel channel = (SocketChannel) key.channel();
                                 ConnectionInfo connection = (ConnectionInfo) key.attachment();
@@ -258,24 +275,18 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
                                     if (key.isReadable()) {
                                         read(channel, connection);
                                     }
-                                    if (connection.getSendingQueue().isEmpty()) {
                                     if (connection.getState() == DISCONNECTED) {
                                         key.interestOps(0);
-                                            key.channel().close();
+                                        channel.close();
+                                    } else if (connection.isWritePending()) {
+                                        key.interestOps(OP_READ | OP_WRITE);
                                     } else {
                                         key.interestOps(OP_READ);
                                     }
-                                    } else {
-                                        key.interestOps(OP_READ | OP_WRITE);
-                                    }
                                 } catch (CancelledKeyException | NodeException | IOException e) {
                                     connection.disconnect();
                                 }
-                                if (connection.getState() == DISCONNECTED) {
-                                    connections.remove(connection);
                             }
-                            }
-                            keyIterator.remove();
                             requestedObjectsCount = requestedObjects.size();
                         }
                         for (Map.Entry<ConnectionInfo, SelectionKey> e : connections.entrySet()) {
@@ -316,7 +327,7 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
     }
 
     private static void read(SocketChannel channel, ConnectionInfo connection) throws IOException {
-        while (channel.read(connection.getInBuffer()) > 0) {
+        if (channel.read(connection.getInBuffer()) > 0) {
             connection.updateReader();
         }
         connection.updateSyncStatus();
@@ -442,6 +453,15 @@ public class NioNetworkHandler implements NetworkHandler, InternalContext.Contex
         );
     }
 
+    private boolean isConnectedTo(NetworkAddress address) {
+        for (ConnectionInfo c : connections.keySet()) {
+            if (c.getNode().equals(address)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     @Override
     public boolean isRunning() {
         return selector != null && selector.isOpen() && starter.isAlive();

repositories/build.gradle

@@ -14,7 +14,7 @@ sourceCompatibility = 1.8
 
 dependencies {
     compile project(':core')
-    compile 'org.flywaydb:flyway-core:3.2.1'
+    compile 'org.flywaydb:flyway-core:4.0.3'
     testCompile 'junit:junit:4.12'
     testCompile 'com.h2database:h2:1.4.190'
     testCompile 'org.mockito:mockito-core:1.10.19'