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

/*

 * Copyright (c) 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: Manuel Requena <manuel.requena@cttc.es>

 */

#ifndef EPC_X2_SAP_H

#define EPC_X2_SAP_H

#include "ns3/packet.h"

#include "ns3/eps-bearer.h"

#include "ns3/ipv4-address.h"

#include <bitset>

namespace ns3 {

class Node;

/**

 * The X2 SAP defines the service between the X2 entity and the RRC entity.

 * 

 * The X2 SAP follows the specification 3GPP TS 36.423: "X2 application protocol (X2AP)"

 * 

 * The service primitives corresponds to the X2AP procedures and messages and 

 * the service parameters corresponds to the Information Elements

 * 

 * Note: Any reference in this file refers to the 3GPP TS 36.423 specification

 */

/**

 * \brief Common structures for EpcX2SapProvider and EpcX2SapUser

 */

class EpcX2Sap

{

public:

  virtual ~EpcX2Sap ();

  /**

   * E-RABs to be setup item as

   * it is used in the HANDOVER REQUEST message.

   * See section 9.1.1.1 for further info about the parameters

   */

  struct ErabToBeSetupItem

  {

    uint16_t    erabId;

    EpsBearer   erabLevelQosParameters;

    bool        dlForwarding;

    Ipv4Address transportLayerAddress;

    uint32_t    gtpTeid;

    ErabToBeSetupItem ();

  };

  /**

   * E-RABs admitted item as

   * it is used in the HANDOVER REQUEST ACKNOWLEDGE message.

   * See section 9.1.1.2 for further info about the parameters

   */

  struct ErabAdmittedItem

  {

    uint16_t    erabId;

    uint32_t    ulGtpTeid;

    uint32_t    dlGtpTeid;

  };

  /**

   * E-RABs not admitted item as

   * it is used in the HANDOVER REQUEST ACKNOWLEDGE message.

   * See section 9.1.1.2 for further info about the parameters

   */

  struct ErabNotAdmittedItem

  {

    uint16_t    erabId;

    uint16_t    cause;

  };

  /**

   * E-RABs subject to status transfer item as

   * it is used in the SN STATUS TRANSFER message.

   * See section 9.1.1.4 for further info about the parameters

   */

  static const uint16_t m_maxPdcpSn = 4096;

  struct ErabsSubjectToStatusTransferItem

  {

    uint16_t            erabId;

    std::bitset<m_maxPdcpSn> receiveStatusOfUlPdcpSdus;

    uint16_t            ulPdcpSn;

    uint32_t            ulHfn;

    uint16_t            dlPdcpSn;

    uint32_t            dlHfn;

  };

  /**

   * UL Interference OverloadIndication as

   * it is used in the LOAD INFORMATION message.

   * See section 9.2.17 for further info about the values

   */

  enum UlInterferenceOverloadIndicationItem

  {

    HighInterference,

    MediumInterference,

    LowInterference

  };

  /**

   * UL High Interference Information as

   * it is used in the LOAD INFORMATION message.

   * See section 9.1.2.1 for further info about the parameters

   */

  struct UlHighInterferenceInformationItem

  {

    uint16_t    targetCellId;

    std::vector <bool> ulHighInterferenceIndicationList;

  };

  /**

   * Relative Narrowband Tx Power (RNTP) as

   * it is used in the LOAD INFORMATION message.

   * See section 9.2.19 for further info about the parameters

   * 

   * Note: You can use INT16_MIN value for -infinite value

   *       in the rntpThreshold field

   */

  struct RelativeNarrowbandTxBand

  {

    std::vector <bool> rntpPerPrbList;

    int16_t     rntpThreshold;

    uint16_t    antennaPorts;

    uint16_t    pB;

    uint16_t    pdcchInterferenceImpact;

  };

  /**

   * Cell Information Item as

   * it is used in the LOAD INFORMATION message.

   * See section 9.1.2.1 for further info about the parameters

   */

  struct CellInformationItem

  {

    uint16_t    sourceCellId;

    std::vector <UlInterferenceOverloadIndicationItem> ulInterferenceOverloadIndicationList;

    std::vector <UlHighInterferenceInformationItem> ulHighInterferenceInformationList;

    RelativeNarrowbandTxBand relativeNarrowbandTxBand;

  };

  /**

   * Load Indicator as

   * it is used in the RESOURCE STATUS UPDATE message.

   * See section 9.2.36 for further info about the value

   */

  enum LoadIndicator

  {

    LowLoad,

    MediumLoad,

    HighLoad,

    Overload

  };

  /**

   * Composite Available Capacity as

   * it is used in the RESOURCE STATUS UPDATE message.

   * See section 9.2.45 for further info about the parameters

   */

  struct CompositeAvailCapacity

  {

    uint16_t    cellCapacityClassValue;

    uint16_t    capacityValue;

  };

  /**

   * Cell Measurement Result Item as

   * it is used in the RESOURCE STATUS UPDATE message.

   * See section 9.1.2.14 for further info about the parameters

   */

  struct CellMeasurementResultItem

  {

    uint16_t        sourceCellId;

    LoadIndicator   dlHardwareLoadIndicator;

    LoadIndicator   ulHardwareLoadIndicator;

    LoadIndicator   dlS1TnlLoadIndicator;

    LoadIndicator   ulS1TnlLoadIndicator;

    uint16_t        dlGbrPrbUsage;

    uint16_t        ulGbrPrbUsage;

    uint16_t        dlNonGbrPrbUsage;

    uint16_t        ulNonGbrPrbUsage;

    uint16_t        dlTotalPrbUsage;

    uint16_t        ulTotalPrbUsage;

    CompositeAvailCapacity  dlCompositeAvailableCapacity;

    CompositeAvailCapacity  ulCompositeAvailableCapacity;

  };

  enum IdCause

  {

    HandoverDesirableForRadioReason,

    TimeCriticalHandover

  };

  /**

   * \brief Parameters of the HANDOVER REQUEST message.

   *

   * See section 9.1.1.1 for further info about the parameters

   */

  struct HandoverRequestParams

  {

    uint16_t            oldEnbUeX2apId;

    uint16_t            cause;

    uint16_t            sourceCellId;

    uint16_t            targetCellId;

    uint32_t            mmeUeS1apId;

    uint64_t            ueAggregateMaxBitRateDownlink;

    uint64_t            ueAggregateMaxBitRateUplink;

    std::vector <ErabToBeSetupItem> bearers;

    Ptr<Packet>         rrcContext;

  };

  /**

   * \brief Parameters of the HANDOVER REQUEST ACKNOWLEDGE message.

   *

   * See section 9.1.1.2 for further info about the parameters

   */

  struct HandoverRequestAckParams

  {

    uint16_t            oldEnbUeX2apId;

    uint16_t            newEnbUeX2apId;

    uint16_t            sourceCellId;

    uint16_t            targetCellId;

    std::vector <ErabAdmittedItem> admittedBearers;

    std::vector <ErabNotAdmittedItem> notAdmittedBearers;

    Ptr<Packet>         rrcContext;

  };

  /**

   * \brief Parameters of the HANDOVER PREPARATION FAILURE message.

   *

   * See section 9.1.1.3 for further info about the parameters

   */

  struct HandoverPreparationFailureParams

  {

    uint16_t            oldEnbUeX2apId;

    uint16_t            sourceCellId;

    uint16_t            targetCellId;

    uint16_t            cause;

    uint16_t            criticalityDiagnostics;

  };

  /**

   * \brief Parameters of the SN STATUS TRANSFER message.

   *

   * See section 9.1.1.4 for further info about the parameters

   */

  struct SnStatusTransferParams

  {

    uint16_t            oldEnbUeX2apId;

    uint16_t            newEnbUeX2apId;

    uint16_t            sourceCellId;

    uint16_t            targetCellId;

    std::vector <ErabsSubjectToStatusTransferItem> erabsSubjectToStatusTransferList;

  };

  /**

   * \brief Parameters of the UE CONTEXT RELEASE message.

   *

   * See section 9.1.1.5 for further info about the parameters

   */

  struct UeContextReleaseParams

  {

    uint16_t            oldEnbUeX2apId;

    uint16_t            newEnbUeX2apId;

    uint16_t            sourceCellId;

    uint16_t            targetCellId;

  };

  /**

   * \brief Parameters of the LOAD INFORMATION message.

   *

   * See section 9.1.2.1 for further info about the parameters

   */

  struct LoadInformationParams

  {

    uint16_t            targetCellId;

    std::vector <CellInformationItem> cellInformationList;

  };

  /**

   * \brief Parameters of the RESOURCE STATUS UPDATE message.

   *

   * See section 9.1.2.14 for further info about the parameters

   */

  struct ResourceStatusUpdateParams

  {

    uint16_t            targetCellId;

    uint16_t            enb1MeasurementId;

    uint16_t            enb2MeasurementId;

    std::vector <CellMeasurementResultItem> cellMeasurementResultList;

  };

  /**

   * \brief Parameters of the UE DATA primitive

   *

   * Forward UE data during the handover procedure from source eNB (sourceCellId)

   * to target eNB (targetCellId) using a GTP-U tunnel (gtpTeid)

   */

  struct UeDataParams

  {

    uint16_t    sourceCellId;

    uint16_t    targetCellId;

    uint32_t    gtpTeid;

    Ptr<Packet> ueData;

  };

};

/**

 * These service primitives of this part of the X2 SAP

 * are provided by the X2 entity and issued by RRC entity

 */

class EpcX2SapProvider : public EpcX2Sap

{

public:

  virtual ~EpcX2SapProvider ();

  /**

   * Service primitives

   */

  virtual void SendHandoverRequest (HandoverRequestParams params) = 0;

  virtual void SendHandoverRequestAck (HandoverRequestAckParams params) = 0;

  virtual void SendHandoverPreparationFailure (HandoverPreparationFailureParams params) = 0;

  virtual void SendSnStatusTransfer (SnStatusTransferParams params) = 0;

  virtual void SendUeContextRelease (UeContextReleaseParams params) = 0;

  virtual void SendLoadInformation (LoadInformationParams params) = 0;

  virtual void SendResourceStatusUpdate (ResourceStatusUpdateParams params) = 0;

  virtual void SendUeData (UeDataParams params) = 0;

};

/**

 * These service primitives of this part of the X2 SAP

 * are provided by the RRC entity and issued by the X2 entity

 */

class EpcX2SapUser : public EpcX2Sap

{

public:

  virtual ~EpcX2SapUser ();

  /**

   * Service primitives

   */

  virtual void RecvHandoverRequest (HandoverRequestParams params) = 0;

  virtual void RecvHandoverRequestAck (HandoverRequestAckParams params) = 0;

  virtual void RecvHandoverPreparationFailure (HandoverPreparationFailureParams params) = 0;

  virtual void RecvSnStatusTransfer (SnStatusTransferParams params) = 0;

  virtual void RecvUeContextRelease (UeContextReleaseParams params) = 0;

  virtual void RecvLoadInformation (LoadInformationParams params) = 0;

  virtual void RecvResourceStatusUpdate (ResourceStatusUpdateParams params) = 0;

  virtual void RecvUeData (UeDataParams params) = 0;

};

///////////////////////////////////////

template <class C>

class EpcX2SpecificEpcX2SapProvider : public EpcX2SapProvider

{

public:

  EpcX2SpecificEpcX2SapProvider (C* x2);

  //

  // Interface implemented from EpcX2SapProvider

  //

  virtual void SendHandoverRequest (HandoverRequestParams params);

  virtual void SendHandoverRequestAck (HandoverRequestAckParams params);

  virtual void SendHandoverPreparationFailure (HandoverPreparationFailureParams params);

  virtual void SendSnStatusTransfer (SnStatusTransferParams params);

  virtual void SendUeContextRelease (UeContextReleaseParams params);

  virtual void SendLoadInformation (LoadInformationParams params);

  virtual void SendResourceStatusUpdate (ResourceStatusUpdateParams params);

  virtual void SendUeData (UeDataParams params);

private:

  EpcX2SpecificEpcX2SapProvider ();

  C* m_x2;

};

template <class C>

EpcX2SpecificEpcX2SapProvider<C>::EpcX2SpecificEpcX2SapProvider (C* x2)

  : m_x2 (x2)

{

}

template <class C>

EpcX2SpecificEpcX2SapProvider<C>::EpcX2SpecificEpcX2SapProvider ()

{

}

template <class C>

void

EpcX2SpecificEpcX2SapProvider<C>::SendHandoverRequest (HandoverRequestParams params)

{

  m_x2->DoSendHandoverRequest (params);

}

template <class C>

void

EpcX2SpecificEpcX2SapProvider<C>::SendHandoverRequestAck (HandoverRequestAckParams params)

{

  m_x2->DoSendHandoverRequestAck (params);

}

template <class C>

void

EpcX2SpecificEpcX2SapProvider<C>::SendHandoverPreparationFailure (HandoverPreparationFailureParams params)

{

  m_x2->DoSendHandoverPreparationFailure (params);

}

template <class C>

void

EpcX2SpecificEpcX2SapProvider<C>::SendSnStatusTransfer (SnStatusTransferParams params)

{

  m_x2->DoSendSnStatusTransfer (params);

}

template <class C>

void

EpcX2SpecificEpcX2SapProvider<C>::SendUeContextRelease (UeContextReleaseParams params)

{

  m_x2->DoSendUeContextRelease (params);

}

template <class C>

void

EpcX2SpecificEpcX2SapProvider<C>::SendLoadInformation (LoadInformationParams params)

{

  m_x2->DoSendLoadInformation (params);

}

template <class C>

void

EpcX2SpecificEpcX2SapProvider<C>::SendResourceStatusUpdate (ResourceStatusUpdateParams params)

{

  m_x2->DoSendResourceStatusUpdate (params);

}

template <class C>

void

EpcX2SpecificEpcX2SapProvider<C>::SendUeData (UeDataParams params)

{

  m_x2->DoSendUeData (params);

}