NetworkInterface.java

/* NetworkInterface.java --
   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2008 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
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this exception to your version of the library, but you are not
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package java.net;

import gnu.classpath.SystemProperties;

import gnu.java.lang.CPStringBuilder;

import java.util.Enumeration;
import java.util.Iterator;
import java.util.Vector;

/**
 * This class models a network interface on the host computer.  A network
 * interface contains a name (typically associated with a specific
 * hardware adapter) and a list of addresses that are bound to it.
 * For example, an ethernet interface may be named "eth0" and have the
 * address 192.168.1.101 assigned to it.
 *
 * @author Michael Koch (konqueror@gmx.de)
 * @since 1.4
 */
public final class NetworkInterface
{
  private final VMNetworkInterface netif;

  private NetworkInterface(VMNetworkInterface netif)
    {
    this.netif = netif;
    }

  /** Creates an NetworkInterface instance which
   * represents any interface in the system. Its only
   * address is <code>0.0.0.0/0.0.0.0</code>. This
   * method is needed by {@link MulticastSocket#getNetworkInterface}
   */
  static NetworkInterface createAnyInterface()
  {
    return new NetworkInterface(new VMNetworkInterface());
  }

  /**
   * Returns the name of the network interface
   *
   * @return The name of the interface.
   */
  public String getName()
  {
    return netif.name;
  }

  /**
   * Returns all available addresses of the network interface
   *
   * If a @see SecurityManager is available all addresses are checked
   * with @see SecurityManager::checkConnect() if they are available.
   * Only <code>InetAddresses</code> are returned where the security manager
   * doesn't throw an exception.
   *
   * @return An enumeration of all addresses.
   */
  public Enumeration<InetAddress> getInetAddresses()
  {
    SecurityManager s = System.getSecurityManager();
    Vector<InetAddress> inetAddresses
      = new Vector<InetAddress>(netif.addresses);

    if (s == null)
      return inetAddresses.elements();

    Vector<InetAddress> tmpInetAddresses = new Vector<InetAddress>(1, 1);

    for (Enumeration<InetAddress> addresses = inetAddresses.elements();
         addresses.hasMoreElements();)
      {
        InetAddress addr = addresses.nextElement();
        try
          {
            s.checkConnect(addr.getHostAddress(), -1);
            tmpInetAddresses.add(addr);
          }
        catch (SecurityException e)
          {
            // Ignore.
          }
      }

    return tmpInetAddresses.elements();
  }

  /**
   * Returns the display name of the interface
   *
   * @return The display name of the interface
   */
  public String getDisplayName()
  {
    return netif.name;
  }

  /**
   * Returns an network interface by name
   *
   * @param name The name of the interface to return
   *
   * @return a <code>NetworkInterface</code> object representing the interface,
   * or null if there is no interface with that name.
   *
   * @exception SocketException If an error occurs
   * @exception NullPointerException If the specified name is null
   */
  public static NetworkInterface getByName(String name)
    throws SocketException
  {
    if (name == null)
      throw new NullPointerException();
    VMNetworkInterface[] netifs = VMNetworkInterface.getVMInterfaces();
    for (int i = 0; i < netifs.length; i++)
      {
        if (netifs[i].name.equals(name))
          return new NetworkInterface(netifs[i]);
      }
    return null;
  }

  /**
   * Return a network interface by its address
   *
   * @param addr The address of the interface to return
   *
   * @return the interface, or <code>null</code> if none found
   *
   * @exception SocketException If an error occurs
   * @exception NullPointerException If the specified addess is null
   */
  public static NetworkInterface getByInetAddress(InetAddress addr)
    throws SocketException
  {
    if (addr == null)
      throw new NullPointerException();
    VMNetworkInterface[] netifs = VMNetworkInterface.getVMInterfaces();
    for (int i = 0; i < netifs.length; i++)
      {
        if (netifs[i].addresses.contains(addr))
          return new NetworkInterface(netifs[i]);
      }
    return null;
  }

  /**
   * Return an <code>Enumeration</code> of all available network interfaces
   *
   * @return all interfaces
   *
   * @exception SocketException If an error occurs
   */
  public static Enumeration<NetworkInterface> getNetworkInterfaces()
    throws SocketException
  {
    VMNetworkInterface[] netifs = VMNetworkInterface.getVMInterfaces();
    Vector<NetworkInterface> networkInterfaces =
      new Vector<NetworkInterface>(netifs.length);
    for (int i = 0; i < netifs.length; i++)
      {
        if (!netifs[i].addresses.isEmpty())
          networkInterfaces.add(new NetworkInterface(netifs[i]));
      }
    return networkInterfaces.elements();
  }

  /**
   * Checks if the current instance is equal to obj
   *
   * @param obj The object to compare with
   *
   * @return <code>true</code> if equal, <code>false</code> otherwise
   */
  public boolean equals(Object obj)
  {
    if (! (obj instanceof NetworkInterface))
      return false;

    NetworkInterface tmp = (NetworkInterface) obj;

    if (netif.name == null)
      return tmp.netif.name == null;

    return (netif.name.equals(tmp.netif.name)
            && (netif.addresses.equals(tmp.netif.addresses)));
  }

  /**
   * Returns the hashcode of the current instance
   *
   * @return the hashcode
   */
  public int hashCode()
  {
    // FIXME: hash correctly
    int hc = netif.addresses.hashCode();

    if (netif.name != null)
      hc += netif.name.hashCode();

    return hc;
  }

  /**
   * Returns a string representation of the interface
   *
   * @return the string
   */
  public String toString()
  {
    // FIXME: check if this is correct
    CPStringBuilder result;
    String separator = SystemProperties.getProperty("line.separator");

    result = new CPStringBuilder();

    result.append("name: ");
    result.append(getDisplayName());
    result.append(" (").append(getName()).append(") addresses:");
    result.append(separator);

    for (Iterator it = netif.addresses.iterator(); it.hasNext(); )
      {
        InetAddress address = (InetAddress) it.next();
        result.append(address.toString()).append(";").append(separator);
      }

    return result.toString();
  }

  /**
   * Determines whether this interface is ready to transfer data.
   *
   * @return whether the interface is up
  */
  public boolean isUp()
    throws SocketException
  {
    return VMNetworkInterface.isUp(netif.name);
  }

  /**
   * Determines whether this interface does point to point
   * transmission.
   *
   * @return whether the interface does point to point transmission
  */
  public boolean isPointToPoint()
    throws SocketException
  {
    return VMNetworkInterface.isPointToPoint(netif.name);
  }

  /**
   * Determines whether this interface is the loopback interface.
   *
   * @return whether the interface is the loopback interface
  */
  public boolean isLoopback()
    throws SocketException
  {
    return VMNetworkInterface.isLoopback(netif.name);
  }

  /**
   * Determines whether this interface supports multicast transmission.
   *
   * @return whether the interface supports multicast transmission.
  */
  public boolean supportsMulticast()
    throws SocketException
  {
    return VMNetworkInterface.supportsMulticast(netif.name);
  }

}