/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2009 University of Washington

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation;

 *

 * 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.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#ifndef IPV4_ROUTING_PROTOCOL_H

#define IPV4_ROUTING_PROTOCOL_H

#include "ns3/packet.h"

#include "ns3/callback.h"

#include "ns3/object.h"

#include "ns3/socket.h"

#include "ipv4-header.h"

namespace ns3 {

class Ipv4MulticastRoute;

class Ipv4Route;

class NetDevice;

/**

 * \ingroup ipv4 

 * Abstract base class for Ipv4 routing protocols.  Defines two

 * virtual functions for packet routing and forwarding.  The first, 

 * RouteOutput(), is used for locally originated packets, and the second,

 * RouteInput(), is used for forwarding and/or delivering received packets. 

 * Also defines the signatures of four callbacks used in RouteInput().

 *

 */

class Ipv4RoutingProtocol : public Object

{

public:

  static TypeId GetTypeId (void);

  typedef Callback<void, Ptr<Ipv4Route>, Ptr<const Packet>, const Ipv4Header &> UnicastForwardCallback;

  typedef Callback<void, Ptr<Ipv4MulticastRoute>, Ptr<const Packet>, const Ipv4Header &> MulticastForwardCallback;

  typedef Callback<void, Ptr<const Packet>, const Ipv4Header &, uint32_t > LocalDeliverCallback;

  typedef Callback<void, Ptr<const Packet>, const Ipv4Header &> ErrorCallback;

  /**

   * \brief Query routing cache for an existing route, for an outbound packet

   *

   * This lookup is used by transport protocols.  It does not cause any

   * packet to be forwarded, and is synchronous.  Can be used for

   * multicast or unicast.  The Linux equivalent is ip_route_output()

   *

   * \param header input parameter (used to form key to search for the route)

   * \param oif Output interface index.  May be zero, or may be bound via

   *            socket options to a particular output interface.

   * \param sockerr Output parameter; socket errno 

   *

   * \returns a code that indicates what happened in the lookup

   */

  virtual Ptr<Ipv4Route> RouteOutput (const Ipv4Header &header, uint32_t oif, Socket::SocketErrno &sockerr) = 0;

  /**

   * \brief Route an input packet (to be forwarded or locally delivered)

   *

   * This lookup is used in the forwarding process.  The packet is

   * handed over to the Ipv4RoutingProtocol, and will get forwarded onward

   * by one of the callbacks.  The Linux equivalent is ip_route_input().

   * There are four valid outcomes, and a matching callbacks to handle each.

   *

   * \param p received packet

   * \param header input parameter used to form a search key for a route

   * \param idev Pointer to ingress network device

   * \param ucb Callback for the case in which the packet is to be forwarded

   *            as unicast

   * \param mcb Callback for the case in which the packet is to be forwarded

   *            as multicast

   * \param lcb Callback for the case in which the packet is to be locally

   *            delivered

   * \param ecb Callback to call if there is an error in forwarding

   * \returns true if the Ipv4RoutingProtocol takes responsibility for 

   *          forwarding or delivering the packet, false otherwise

   */ 

  virtual bool RouteInput  (Ptr<const Packet> p, const Ipv4Header &header, Ptr<const NetDevice> idev, 

                             UnicastForwardCallback ucb, MulticastForwardCallback mcb, 

                             LocalDeliverCallback lcb, ErrorCallback ecb) = 0;

};

} //namespace ns3

#endif /* IPV4_ROUTING_PROTOCOL_H */