src/frontends/android/src/org/strongswan/android/logic/NetworkManager.java

   1 /*
   2  * Copyright (C) 2012 Tobias Brunner
   3  * Hochschule fuer Technik Rapperswil
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * for more details.
  14  */
  15
  16 package org.strongswan.android.logic;
  17
  18 import java.net.Inet4Address;
  19 import java.net.Inet6Address;
  20 import java.net.InetAddress;
  21 import java.net.NetworkInterface;
  22 import java.net.SocketException;
  23 import java.util.Enumeration;
  24
  25 public class NetworkManager
  26 {
  27         public NetworkManager()
  28         {
  29         }
  30
  31         /**
  32          * Function that retrieves a local address of the given family.
  33          *
  34          * @param ipv4 true to return an IPv4 address, false for IPv6
  35          * @return string representation of an IPv4 address, or null if none found
  36          */
  37         public String getLocalAddress(boolean ipv4)
  38         {
  39                 try
  40                 {
  41                         Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces();
  42                         if (en == null)
  43                         {       /* no interfaces at all */
  44                                 return null;
  45                         }
  46                         while (en.hasMoreElements())
  47                         {
  48                                 NetworkInterface intf = en.nextElement();
  49                                 if (intf.isLoopback() || !intf.isUp() ||
  50                                         intf.getName().startsWith("tun"))
  51                                 {
  52                                         continue;
  53                                 }
  54                                 Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses();
  55                                 while (enumIpAddr.hasMoreElements())
  56                                 {
  57                                         InetAddress inetAddress = enumIpAddr.nextElement();
  58                                         if (inetAddress.isLoopbackAddress())
  59                                         {
  60                                                 continue;
  61                                         }
  62                                         if ((ipv4 && inetAddress instanceof Inet4Address) ||
  63                                                 (!ipv4 && inetAddress instanceof Inet6Address))
  64                                         {
  65                                                 return inetAddress.getHostAddress();
  66                                         }
  67                                 }
  68                         }
  69                 }
  70                 catch (SocketException ex)
  71                 {
  72                         ex.printStackTrace();
  73                         return null;
  74                 }
  75                 return null;
  76         }
  77 }