/* -*-  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_ENB_APPLICATION_H

#define EPC_ENB_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/lte-common.h>

#include <ns3/application.h>

#include <ns3/eps-bearer.h>

#include <ns3/epc-enb-s1-sap.h>

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

#include <map>

namespace ns3 {

class EpcEnbS1SapUser;

class EpcEnbS1SapProvider;

/**

 * \ingroup lte

 *

 * This application is installed inside eNBs and provides the bridge functionality for user data plane packets between the radio interface and the S1-U interface.

 */

class EpcEnbApplication : public Application

{

  friend class MemberEpcEnbS1SapProvider<EpcEnbApplication>;

  friend class MemberEpcS1apSapEnb<EpcEnbApplication>;

public:

  /**

   * \brief Get the type ID.

   * \return the object TypeId

   */

  static TypeId GetTypeId (void);

protected:

  void DoDispose (void);

public:

  /** 

   * Constructor

   * 

   * \param lteSocket the socket to be used to send/receive packets to/from the LTE radio interface

   * \param s1uSocket the socket to be used to send/receive packets

   * to/from the S1-U interface connected with the SGW 

   * \param enbS1uAddress the IPv4 address of the S1-U interface of this eNB

   * \param sgwS1uAddress the IPv4 address at which this eNB will be able to reach its SGW for S1-U communications

   * \param cellId the identifier of the enb

   */

  EpcEnbApplication (Ptr<Socket> lteSocket, Ptr<Socket> s1uSocket, Ipv4Address enbS1uAddress, Ipv4Address sgwS1uAddress, uint16_t cellId);

  /**

   * Destructor

   * 

   */

  virtual ~EpcEnbApplication (void);

  /** 

   * Set the S1 SAP User

   * 

   * \param s the S1 SAP User

   */

  void SetS1SapUser (EpcEnbS1SapUser * s);

  /** 

   * 

   * \return the S1 SAP Provider

   */

  EpcEnbS1SapProvider* GetS1SapProvider ();

  /** 

   * Set the MME side of the S1-AP SAP 

   * 

   * \param s the MME side of the S1-AP SAP 

   */

  void SetS1apSapMme (EpcS1apSapMme * s);

  /** 

   * 

   * \return the ENB side of the S1-AP SAP 

   */

  EpcS1apSapEnb* GetS1apSapEnb ();

  /** 

   * Method to be assigned to the recv callback of the LTE socket. It is called when the eNB receives a data packet from the radio interface that is to be forwarded to the SGW.

   * 

   * \param socket pointer to the LTE socket

   */

  void RecvFromLteSocket (Ptr<Socket> socket);

  /** 

   * Method to be assigned to the recv callback of the S1-U socket. It is called when the eNB receives a data packet from the SGW that is to be forwarded to the UE.

   * 

   * \param socket pointer to the S1-U socket

   */

  void RecvFromS1uSocket (Ptr<Socket> socket);

  /**

   * EPS flow ID structure

   */

  struct EpsFlowId_t

  {

    uint16_t  m_rnti; ///< RNTI

    uint8_t   m_bid; ///< Bid, the EPS Bearer IDentifier

  public:

    EpsFlowId_t ();

    /**

     * Constructor

     *

     * \param a RNTI

     * \param b bid

     */

    EpsFlowId_t (const uint16_t a, const uint8_t b);

    /**

     * Comparison operator

     *

     * \param a first application

     * \param b second application

     * \returns true is the applications are "equal"

     */

    friend bool operator == (const EpsFlowId_t &a, const EpsFlowId_t &b);

    /**

     * Less than operator

     *

     * \param a first application

     * \param b second application

     * \returns true is the applications are "equal"

     */

    friend bool operator < (const EpsFlowId_t &a, const EpsFlowId_t &b);

  };

private:

  // ENB S1 SAP provider methods

  /**

   * Initial UE message function

   * \param imsi the IMSI

   * \param rnti the RNTI

   */

  void DoInitialUeMessage (uint64_t imsi, uint16_t rnti);

  /**

   * Path switch request function

   * \param params PathSwitchRequestParameters

   */

  void DoPathSwitchRequest (EpcEnbS1SapProvider::PathSwitchRequestParameters params);

  /**

   * UE Context Release function

   * \param rnti the RNTI

   */

  void DoUeContextRelease (uint16_t rnti);

  // S1-AP SAP ENB methods

  /**

   * Initial Context Setup Request 

   * \param mmeUeS1Id the MME UE S1 ID

   * \param enbUeS1Id the ENB UE S1 ID

   * \param erabToBeSetupList the ERAB setup list

   */

  void DoInitialContextSetupRequest (uint64_t mmeUeS1Id, uint16_t enbUeS1Id, std::list<EpcS1apSapEnb::ErabToBeSetupItem> erabToBeSetupList);

  /**

   * Path Switch Request Acknowledge 

   * \param mmeUeS1Id the MME UE S1 ID

   * \param enbUeS1Id the ENB UE S1 ID

   * \param cgi the CGI

   * \param erabToBeSwitchedInUplinkList the ERAB switched in uplink list

   */

  void DoPathSwitchRequestAcknowledge (uint64_t enbUeS1Id, uint64_t mmeUeS1Id, uint16_t cgi, std::list<EpcS1apSapEnb::ErabSwitchedInUplinkItem> erabToBeSwitchedInUplinkList);

  /** 

   * \brief This function accepts bearer id corresponding to a particular UE and schedules indication of bearer release towards MME

   * \param imsi maps to mmeUeS1Id

   * \param rnti maps to enbUeS1Id

   * \param bearerId Bearer Identity which is to be de-activated

   */

  void DoReleaseIndication (uint64_t imsi, uint16_t rnti, uint8_t bearerId);

  /**

   * Send a packet to the UE via the LTE radio interface of the eNB

   * 

   * \param packet t

   * \param rnti maps to enbUeS1Id

   * \param bid the EPS Bearer IDentifier

   */

  void SendToLteSocket (Ptr<Packet> packet, uint16_t rnti, uint8_t bid);

  /** 

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

   * 

   * \param packet packet to be sent

   * \param teid the Tunnel Enpoint IDentifier

   */

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

  /** 

   * internal method used for the actual setup of the S1 Bearer

   * 

   * \param teid the Tunnel Endpoint IDentifier

   * \param rnti maps to enbUeS1Id

   * \param bid the S1-U Bearer IDentifier

   */

  void SetupS1Bearer (uint32_t teid, uint16_t rnti, uint8_t bid);

  /**

   * raw packet socket to send and receive the packets to and from the LTE radio interface

   */

  Ptr<Socket> m_lteSocket;

  /**

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

   */

  Ptr<Socket> m_s1uSocket;

  /**

   * address of the eNB for S1-U communications

   */

  Ipv4Address m_enbS1uAddress;

  /**

   * address of the SGW which terminates all S1-U tunnels

   */

  Ipv4Address m_sgwS1uAddress;

  /**

   * map of maps telling for each RNTI and BID the corresponding  S1-U TEID

   * 

   */

  std::map<uint16_t, std::map<uint8_t, uint32_t> > m_rbidTeidMap;  

  /**

   * map telling for each S1-U TEID the corresponding RNTI,BID

   * 

   */

  std::map<uint32_t, EpsFlowId_t> m_teidRbidMap;

  /**

   * UDP port to be used for GTP

   */

  uint16_t m_gtpuUdpPort;

  /**

   * Provider for the S1 SAP 

   */

  EpcEnbS1SapProvider* m_s1SapProvider;

  /**

   * User for the S1 SAP 

   */

  EpcEnbS1SapUser* m_s1SapUser;

  /**

   * MME side of the S1-AP SAP

   * 

   */

  EpcS1apSapMme* m_s1apSapMme;

  /**

   * ENB side of the S1-AP SAP

   * 

   */

  EpcS1apSapEnb* m_s1apSapEnb;

  /**

   * UE context info

   * 

   */

  std::map<uint64_t, uint16_t> m_imsiRntiMap;

  uint16_t m_cellId; ///< cell ID

};

} //namespace ns3

#endif /* EPC_ENB_APPLICATION_H */