Fix local port forwarding disconnecting issue (#491)

* `SocketStreamCopyMonitor` closes channel after setting the one event. It doesn't wait for the second stream to finish the job.

* #317 Fix `SocketStreamCopyMonitor` to wait for all events before closing the channel.

src/main/java/net/schmizz/sshj/connection/channel/SocketStreamCopyMonitor.java

@@ -39,15 +39,21 @@ public class SocketStreamCopyMonitor
         new SocketStreamCopyMonitor(new Runnable() {
             public void run() {
                 try {
-                    for (Event<IOException> ev = x;
-                         !ev.tryAwait(frequency, unit);
-                         ev = (ev == x) ? y : x) {
-                    }
+                    await(x);
+                    await(y);
                 } catch (IOException ignored) {
                 } finally {
                     IOUtils.closeQuietly(channel, asCloseable(socket));
                 }
             }
+
+            private void await(final Event<IOException> event) throws IOException {
+                while(true){
+                    if(event.tryAwait(frequency, unit)){
+                        break;
+                    }
+                }
+            }
         }).start();
     }
 

src/test/java/net/schmizz/sshj/connection/channel/SocketStreamCopyMonitorTest.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright (C)2009 - SSHJ Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.schmizz.sshj.connection.channel;
+
+import net.schmizz.concurrent.Event;
+import net.schmizz.concurrent.ExceptionChainer;
+import net.schmizz.sshj.common.LoggerFactory;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.net.Socket;
+import java.util.concurrent.TimeUnit;
+
+import static org.mockito.Mockito.*;
+
+public class SocketStreamCopyMonitorTest {
+
+    @Test
+    public void shouldNotCloseChannelIfOnlyFirstEventSet() throws Exception {
+        final Channel channel = mock(Channel.class);
+        final Socket socket = mock(Socket.class);
+        final Event<IOException> xEvent = createEvent();
+        final Event<IOException> yEvent = createEvent();
+        SocketStreamCopyMonitor.monitor(1, TimeUnit.MILLISECONDS, xEvent, yEvent, channel, socket);
+
+        xEvent.set();
+
+        waitForMonitorThreadToCloseTheChannel();
+
+        verify(channel, never()).close();
+    }
+
+    @Test
+    public void shouldNotCloseChannelIfOnlySecondEventSet() throws Exception {
+        final Channel channel = mock(Channel.class);
+        final Socket socket = mock(Socket.class);
+        final Event<IOException> xEvent = createEvent();
+        final Event<IOException> yEvent = createEvent();
+        SocketStreamCopyMonitor.monitor(1, TimeUnit.MILLISECONDS, xEvent, yEvent, channel, socket);
+
+        yEvent.set();
+
+        waitForMonitorThreadToCloseTheChannel();
+
+        verify(channel, never()).close();
+    }
+
+    @Test
+    public void shouldCloseChannelIfBothEventsSet() throws Exception {
+        final Channel channel = mock(Channel.class);
+        final Socket socket = mock(Socket.class);
+        final Event<IOException> xEvent = createEvent();
+        final Event<IOException> yEvent = createEvent();
+        SocketStreamCopyMonitor.monitor(1, TimeUnit.MILLISECONDS, xEvent, yEvent, channel, socket);
+
+        xEvent.set();
+        yEvent.set();
+
+        waitForMonitorThreadToCloseTheChannel();
+
+        verify(channel, times(1)).close();
+    }
+
+    private void waitForMonitorThreadToCloseTheChannel() throws InterruptedException {
+        Thread.sleep(50);
+    }
+
+    private Event<IOException> createEvent() {
+        return new Event<IOException>("event", new ExceptionChainer<IOException>() {
+            @Override
+            public IOException chain(Throwable t) {
+                return new IOException(t);
+            }
+        }, LoggerFactory.DEFAULT);
+    }
+}