content: /*
   * Copyright (C) 2013 4th Line GmbH, Switzerland
   *
   * The contents of this file are subject to the terms of either the GNU
   * Lesser General Public License Version 2 or later ("LGPL") or the
   * Common Development and Distribution License Version 1 or later
   * ("CDDL") (collectively, the "License"). You may not use this file
   * except in compliance with the License. See LICENSE.txt for more
   * information.
   *
   * This program 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.
   */
  
  package org.fourthline.cling.transport.spi;
  
  import java.net.InetAddress;
  import java.net.NetworkInterface;
  import java.util.Iterator;
  
  /**
   * Configuration utility for network interfaces and addresses.
   * <p>
   * An implementation has to be thread-safe.
   * </p>
   *
   * @author Christian Bauer
   */
  public interface NetworkAddressFactory {
  
      // An implementation can honor these if it wants (the default does)
      public static final String SYSTEM_PROPERTY_NET_IFACES = "org.fourthline.cling.network.useInterfaces";
      public static final String SYSTEM_PROPERTY_NET_ADDRESSES = "org.fourthline.cling.network.useAddresses";
  
  
      /**
       * @return The UDP multicast group to join.
       */
      public InetAddress getMulticastGroup();
  
      /**
       * @return The UDP multicast port to listen on.
       */
      public int getMulticastPort();
  
      /**
       * @return The TCP (HTTP) stream request port to listen on.
       */
      public int getStreamListenPort();
  
      /**
       * The caller might <code>remove()</code> an interface if initialization fails.
       *
       * @return The local network interfaces on which multicast groups will be joined.
       */
      public Iterator<NetworkInterface> getNetworkInterfaces();
  
      /**
       * The caller might <code>remove()</code> an address if initialization fails.
       *
       * @return The local addresses of the network interfaces bound to
       *         sockets listening for unicast datagrams and TCP requests.
       */
      public Iterator<InetAddress> getBindAddresses();
  
      /**
       * @return <code>true</code> if there is at least one usable network interface and bind address.
       */
      public boolean hasUsableNetwork();
  
      /**
       * @return The network prefix length of this address or <code>null</code>.
       */
      public Short getAddressNetworkPrefixLength(InetAddress inetAddress);
  
      /**
       * @param inetAddress An address of a local network interface.
       * @return The MAC hardware address of the network interface or <code>null</code> if no
       *         hardware address could be obtained.
       */
      public byte[] getHardwareAddress(InetAddress inetAddress);
  
      /**
       * @param inetAddress An address of a local network interface.
       * @return The broadcast address of the network (interface) or <code>null</code> if no
       *         broadcast address could be obtained.
       */
      public InetAddress getBroadcastAddress(InetAddress inetAddress);
  
      /**
       * Best-effort attempt finding a reachable local address for a given remote host.
       * <p>
       * This method is called whenever a multicast datagram has been received. We need to be
       * able to communicate with the sender using UDP unicast and we need to tell the sender
       * how we are reachable with TCP requests. We need a local address that is in the same
       * subnet as the senders address, that is reachable from the senders point of view.
       * </p>
       *
       * @param networkInterface The network interface to examine.
       * @param isIPv6 True if the given remote address is an IPv6 address.
       * @param remoteAddress The remote address for which to find a local address in the same subnet.
       * @return A local address that is reachable from the given remote address.
       * @throws IllegalStateException If no local address reachable by the remote address has been found.
       */
      public InetAddress getLocalAddress(NetworkInterface networkInterface,
                                         boolean isIPv6,
                                         InetAddress remoteAddress) throws IllegalStateException;
  
      /**
       * For debugging, logs all "usable" network interface(s) details with INFO level.
       */
      public void logInterfaceInformation();
  }
  