Implement flexible port selection in Socks5ClientTest

smack-core/src/test/java/org/jivesoftware/smack/util/NetworkUtil.java

@@ -0,0 +1,54 @@
+/**
+ *
+ * Copyright 2016 Florian Schmaus
+ *
+ * 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 org.jivesoftware.smack.util;
+
+import java.io.IOException;
+import java.net.BindException;
+import java.net.InetAddress;
+import java.net.ServerSocket;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class NetworkUtil {
+
+    private static final Logger LOGGER = Logger.getLogger(NetworkUtil.class.getName());
+
+    public static ServerSocket getSocketOnLoopback() {
+        final InetAddress loopbackAddress = InetAddress.getLoopbackAddress();
+        final int portMin = 1024;
+        final int portMax = (1 << 16) - 1;
+        final int backlog = 1;
+
+        ServerSocket serverSocket = null;
+        for (int port = portMin; port <= portMax; port++) {
+            try {
+                serverSocket = new ServerSocket(port, backlog, loopbackAddress);
+                break;
+            } catch (BindException e) {
+                LOGGER.log(Level.FINEST, "Could not bind port " + port + ", trying next", e);
+            } catch (IOException e) {
+                throw new IllegalStateException(e);
+            }
+        }
+
+        if (serverSocket == null) {
+            throw new IllegalStateException();
+        }
+
+        return serverSocket;
+    }
+}