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

/*

 * Copyright (c) 2011-2012 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)

 *

 * 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

 *

 * Author: Jaume Nin <jnin@cttc.es>

 *         Nicola Baldo <nbaldo@cttc.es>

 *         Manuel Requena <manuel.requena@cttc.es>

 */

#ifndef EPC_HELPER_H

#define EPC_HELPER_H

#include <ns3/object.h>

#include <ns3/ipv4-address-helper.h>

#include <ns3/data-rate.h>

#include <ns3/epc-tft.h>

#include <ns3/eps-bearer.h>

namespace ns3 {

class Node;

class NetDevice;

class VirtualNetDevice;

class EpcSgwPgwApplication;

class EpcX2;

class EpcMme;

/**

 * \brief Helper class to handle the creation of the EPC entities and protocols.

 *

 * This Helper will create an EPC network topology comprising of a

 * single node that implements both the SGW and PGW functionality, and

 * is connected to all the eNBs in the simulation by means of the S1-U

 * interface. 

 */

class EpcHelper : public Object

{

public:

  /** 

   * Constructor

   */

  EpcHelper ();

  /** 

   * Destructor

   */  

  virtual ~EpcHelper ();

  // inherited from Object

  static TypeId GetTypeId (void);

  virtual void DoDispose ();

  /** 

   * Add an eNB to the EPC

   * 

   * \param enbNode the previosuly created eNB node which is to be

   * added to the EPC

   * \param lteEnbNetDevice the LteEnbNetDevice of the eNB node

   * \param cellId ID of the eNB

   */

  void AddEnb (Ptr<Node> enbNode, Ptr<NetDevice> lteEnbNetDevice, uint16_t cellId);

  /** 

   * Notify the EPC of the existance of a new UE which might attach at a later time

   * 

   * \param ueLteDevice the UE device to be attached

   * \param imsi the unique identifier of the UE

   */

  void AddUe (Ptr<NetDevice> ueLteDevice, uint64_t imsi);

  /** 

   * Add an X2 interface between two eNB

   * 

   * \param enbNode1 one eNB peer of the X2 interface

   * \param enbNode2 the other eNB peer of the X2 interface

   */

  void AddX2Interface (Ptr<Node> enbNode1, Ptr<Node> enbNode2);

  /** 

   * Activate an EPS bearer, setting up the corresponding S1-U tunnel.

   * 

   * 

   * 

   * \param ueLteDevice the Ipv4-enabled device of the UE, normally

   * connected via the LTE radio interface

   * \param imsi the unique identifier of the UE

   * \param tft the Traffic Flow Template of the new bearer

   * \param bearer struct describing the characteristics of the EPS bearer to be activated

   */

  void ActivateEpsBearer (Ptr<NetDevice> ueLteDevice, uint64_t imsi, Ptr<EpcTft> tft, EpsBearer bearer);

  /** 

   * 

   * \return a pointer to the node implementing PGW

   * functionality. Note that in this particular implementation this

   * node will also hold the SGW functionality. The primary use

   * intended for this method is to allow the user to configure the Gi

   * interface of the PGW, i.e., to connect the PGW to the internet.

   */

  Ptr<Node> GetPgwNode ();

  /** 

   * Assign IPv4 addresses to UE devices

   * 

   * \param ueDevices the set of UE devices

   * 

   * \return the interface container, \see Ipv4AddressHelper::Assign() which has similar semantics

   */

  Ipv4InterfaceContainer AssignUeIpv4Address (NetDeviceContainer ueDevices);

  /** 

   * 

   * \return the address of the Default Gateway to be used by UEs to reach the internet

   */

  Ipv4Address GetUeDefaultGatewayAddress ();

private:

  /**

   * SGW-PGW network element

   */

  /** 

   * helper to assign addresses to UE devices as well as to the TUN device of the SGW/PGW

   */

  Ipv4AddressHelper m_ueAddressHelper; 

  Ptr<Node> m_sgwPgw; 

  Ptr<EpcSgwPgwApplication> m_sgwPgwApp;

  Ptr<VirtualNetDevice> m_tunDevice;

  Ptr<EpcMme> m_mme;

  /**

   * S1-U interfaces

   */

  /** 

   * helper to assign addresses to S1-U NetDevices 

   */

  Ipv4AddressHelper m_s1uIpv4AddressHelper; 

  DataRate m_s1uLinkDataRate;

  Time     m_s1uLinkDelay;

  uint16_t m_s1uLinkMtu;

  /**

   * UDP port where the GTP-U Socket is bound, fixed by the standard as 2152

   */

  uint16_t m_gtpuUdpPort;

  /**

   * Map storing for each IMSI the corresponding eNB NetDevice

   * 

   */

  std::map<uint64_t, Ptr<NetDevice> > m_imsiEnbDeviceMap;

  /** 

   * helper to assign addresses to X2 NetDevices 

   */

  Ipv4AddressHelper m_x2Ipv4AddressHelper;   

  DataRate m_x2LinkDataRate;

  Time     m_x2LinkDelay;

  uint16_t m_x2LinkMtu;

};

} // namespace ns3

#endif // EPC_HELPER_H