content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.apache.camel.kafkaconnector.common.utils;
  
  import java.io.IOException;
  import java.net.ConnectException;
  import java.net.DatagramSocket;
  import java.net.InetSocketAddress;
  import java.net.ServerSocket;
  import java.net.Socket;
  import java.net.UnknownHostException;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public final class NetworkUtils {
      
      public static final int  DEFAULT_ENDING_PORT = 65535;
      public static final int  DEFAULT_STARTING_PORT = 49152;
      public static int freeStartingPort = DEFAULT_STARTING_PORT;
      private static final Logger LOG = LoggerFactory.getLogger(NetworkUtils.class);
  
      private NetworkUtils() {
          // utils class
      }
  
      public static int getFreePort() {
          return getFreePort(getHostname());
      }
  
      public static int getFreePort(String host) {
          return getFreePort(host, freeStartingPort, DEFAULT_ENDING_PORT);
      }
  
      public static int getFreePort(String host, Protocol protocol) {
          return getFreePort(host, freeStartingPort, DEFAULT_ENDING_PORT, protocol);
      }
  
      public static int getFreePort(String host, int startingPort, int endingPort) {
          return getFreePort(host, startingPort, endingPort, Protocol.TCP);
      }
  
      public static synchronized int getFreePort(String host, int startingPort, int endingPort, Protocol protocol) {
          int freePort = 0;
          for (int i = startingPort; i <= endingPort; i++) {
              boolean found = checkPort(host, i, protocol);
              if (found) {
                  freePort = i;
                  break;
              }
          }
          return freePort;
      }
  
      public static boolean checkPort(String host, int port, Protocol protocol) {
          try {
              switch (protocol) {
                  case TCP:
                      try (ServerSocket ss = new ServerSocket()) {
                          ss.setReuseAddress(true);
                          ss.bind(new InetSocketAddress(host, port), 1);
                          ss.getLocalPort();
                          if (port == freeStartingPort) {
                              freeStartingPort++;
                          }
                          return true;
                      } catch (IOException e) {
                          return false;
                      }
                  case UDP:
                      (new DatagramSocket(new InetSocketAddress(host, port))).close();
                      if (port == freeStartingPort) {
                          freeStartingPort++;
                      }
                      return true;
                  default:
                      return false;
              }
          } catch (IOException e) {
              return false;
          }
      }
  
      public static boolean portIsOpen(String host, int port) {
          try (Socket socket = new Socket(host, port)) {
              return true;
          } catch (UnknownHostException e) {
              LOG.warn("Unknown host: {}", host);
              return false;
          } catch (IOException e) {
              if (e instanceof ConnectException) {
                  LOG.info("Port {} is likely closed: {}", port, e.getMessage());
              } else {
                  LOG.warn("Unhandled I/O exception: {}", e.getMessage(), e);
              }
  
              return false;
          }
      }
  
      public enum Protocol {
          UDP,
          TCP
      }
  
      public static String getHostname() {
          return "localhost";
      }
  
      public static String getAddress(String protocol) {
          return String.format("%s://%s:%d", protocol, NetworkUtils.getHostname(), NetworkUtils.getFreePort());
      }
  
      public static String getAddress(String protocol, int port) {
          return String.format("%s://%s:%d", protocol, NetworkUtils.getHostname(), port);
      }
  }
  