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

/*

 * Copyright (c) 2011 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.cat>

 *         Nicola Baldo <nbaldo@cttc.cat>

 */

#ifndef EPC_SGW_PGW_APPLICATION_H

#define EPC_SGW_PGW_APPLICATION_H

#include <ns3/address.h>

#include <ns3/socket.h>

#include <ns3/virtual-net-device.h>

#include <ns3/traced-callback.h>

#include <ns3/callback.h>

#include <ns3/ptr.h>

#include <ns3/object.h>

#include <ns3/eps-bearer.h>

#include <ns3/epc-tft.h>

#include <ns3/epc-tft-classifier.h>

#include <ns3/lte-common.h>

#include <ns3/application.h>

#include <ns3/epc-s1ap-sap.h>

#include <ns3/epc-s11-sap.h>

#include <map>

namespace ns3 {

/**

 * \ingroup lte

 *

 * This application implements the SGW/PGW functionality.

 */

class EpcSgwPgwApplication : public Application

{

  friend class MemberEpcS11SapSgw<EpcSgwPgwApplication>;

public:

  // inherited from Object

  static TypeId GetTypeId (void);

  virtual void DoDispose ();

  /**

   * Constructor that binds the tap device to the callback methods.

   *

   * \param tunDevice TUN VirtualNetDevice used to tunnel IP packets from

   * the Gi interface of the PGW/SGW over the

   * internet over GTP-U/UDP/IP on the S1-U interface

   * \param s1uSocket socket used to send GTP-U packets to the eNBs

   */

  EpcSgwPgwApplication (const Ptr<VirtualNetDevice> tunDevice, const Ptr<Socket> s1uSocket);

  /** 

   * Destructor

   */

  virtual ~EpcSgwPgwApplication (void);

  /** 

   * Method to be assigned to the callback of the Gi TUN VirtualNetDevice. It

   * is called when the SGW/PGW receives a data packet from the

   * internet (including IP headers) that is to be sent to the UE via

   * its associated eNB, tunneling IP over GTP-U/UDP/IP.

   * 

   * \param packet 

   * \param source 

   * \param dest 

   * \param protocolNumber 

   * \return true always 

   */

  bool RecvFromTunDevice (Ptr<Packet> packet, const Address& source, const Address& dest, uint16_t protocolNumber);

  /** 

   * Method to be assigned to the recv callback of the S1-U socket. It

   * is called when the SGW/PGW receives a data packet from the eNB

   * that is to be forwarded to the internet. 

   * 

   * \param socket pointer to the S1-U socket

   */

  void RecvFromS1uSocket (Ptr<Socket> socket);

  /** 

   * Send a packet to the internet via the Gi interface of the SGW/PGW

   * 

   * \param packet 

   */

  void SendToTunDevice (Ptr<Packet> packet, uint32_t teid);

  /** 

   * Send a packet to the SGW via the S1-U interface

   * 

   * \param packet packet to be sent

   * \param enbS1uAddress the address of the eNB

   * \param teid the Tunnel Enpoint IDentifier

   */

  void SendToS1uSocket (Ptr<Packet> packet, Ipv4Address enbS1uAddress, uint32_t teid);

  /** 

   * Set the MME side of the S11 SAP 

   * 

   * \param s the MME side of the S11 SAP 

   */

  void SetS11SapMme (EpcS11SapMme * s);

  /** 

   * 

   * \return the SGW side of the S11 SAP 

   */

  EpcS11SapSgw* GetS11SapSgw ();

  /** 

   * Let the SGW be aware of a new eNB 

   * 

   * \param cellId the cell identifier

   * \param enbAddr the address of the eNB

   * \param sgwAddr the address of the SGW

   */

  void AddEnb (uint16_t cellId, Ipv4Address enbAddr, Ipv4Address sgwAddr);

  /** 

   * Let the SGW be aware of a new UE

   * 

   * \param imsi the unique identifier of the UE

   */

  void AddUe (uint64_t imsi);

  /** 

   * set the address of a previously added UE

   * 

   * \param imsi the unique identifier of the UE

   * \param ueAddr the IPv4 address of the UE

   */

  void SetUeAddress (uint64_t imsi, Ipv4Address ueAddr);

private:

  // S11 SAP SGW methods

  void DoCreateSessionRequest (EpcS11SapSgw::CreateSessionRequestMessage msg);

  void DoModifyBearerRequest (EpcS11SapSgw::ModifyBearerRequestMessage msg);  

  void DoDeleteBearerCommand (EpcS11SapSgw::DeleteBearerCommandMessage req);

  void DoDeleteBearerResponse (EpcS11SapSgw::DeleteBearerResponseMessage req);

  /**

   * store info for each UE connected to this SGW

   */

  class UeInfo : public SimpleRefCount<UeInfo>

  {

public:

    UeInfo ();  

    /** 

     * 

     * \param tft the Traffic Flow Template of the new bearer to be added

     * \param epsBearerId the ID of the EPS Bearer to be activated

     * \param teid  the TEID of the new bearer

     */

    void AddBearer (Ptr<EpcTft> tft, uint8_t epsBearerId, uint32_t teid);

    /** 

     * \brief Function, deletes contexts of bearer on SGW and PGW side

     * \param bearerId, the Bearer Id whose contexts to be removed

     */

    void RemoveBearer (uint8_t bearerId);

    /**

     * 

     * 

     * \param p the IP packet from the internet to be classified

     * 

     * \return the corresponding bearer ID > 0 identifying the bearer

     * among all the bearers of this UE;  returns 0 if no bearers

     * matches with the previously declared TFTs

     */

    uint32_t Classify (Ptr<Packet> p);

    /** 

     * \return the address of the eNB to which the UE is connected

     */

    Ipv4Address GetEnbAddr ();

    /** 

     * set the address of the eNB to which the UE is connected

     * 

     * \param addr the address of the eNB

     */

    void SetEnbAddr (Ipv4Address addr);

    /** 

     * \return the address of the UE

     */

    Ipv4Address GetUeAddr ();

    /** 

     * set the address of the UE

     * 

     * \param addr the address of the UE

     */

    void SetUeAddr (Ipv4Address addr);

  private:

    EpcTftClassifier m_tftClassifier;

    Ipv4Address m_enbAddr;

    Ipv4Address m_ueAddr;

    std::map<uint8_t, uint32_t> m_teidByBearerIdMap;

  };

 /**

  * UDP socket to send and receive GTP-U packets to and from the S1-U interface

  */

  Ptr<Socket> m_s1uSocket;

  /**

   * TUN VirtualNetDevice used for tunneling/detunneling IP packets

   * from/to the internet over GTP-U/UDP/IP on the S1 interface 

   */

  Ptr<VirtualNetDevice> m_tunDevice;

  /**

   * Map telling for each UE address the corresponding UE info 

   */

  std::map<Ipv4Address, Ptr<UeInfo> > m_ueInfoByAddrMap;

  /**

   * Map telling for each IMSI the corresponding UE info 

   */

  std::map<uint64_t, Ptr<UeInfo> > m_ueInfoByImsiMap;

  /**

   * UDP port to be used for GTP

   */

  uint16_t m_gtpuUdpPort;

  uint32_t m_teidCount;

  /**

   * MME side of the S11 SAP

   * 

   */

  EpcS11SapMme* m_s11SapMme;

  /**

   * SGW side of the S11 SAP

   * 

   */

  EpcS11SapSgw* m_s11SapSgw;

  struct EnbInfo

  {

    Ipv4Address enbAddr;

    Ipv4Address sgwAddr;    

  };

  std::map<uint16_t, EnbInfo> m_enbInfoByCellId;

};

} //namespace ns3

#endif /* EPC_SGW_PGW_APPLICATION_H */