/* -*-  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>

 */

#ifndef EPS_GTPU_V1_H

#define EPS_GTPU_V1_H

#include <ns3/ptr.h>

#include <ns3/header.h>

#include <ns3/ipv4-header.h>

namespace ns3 {

class Packet;

/**

 * \ingroup lte

 *

 * Implementation of the GTPv1-U Release 10 as per 3Gpp TS 29.281 document

 */

class GtpuHeader : public Header

{

public:

  static TypeId GetTypeId (void);

  GtpuHeader ();

  virtual ~GtpuHeader ();

  virtual TypeId GetInstanceTypeId (void) const;

  virtual uint32_t GetSerializedSize (void) const;

  virtual void Serialize (Buffer::Iterator start) const;

  virtual uint32_t Deserialize (Buffer::Iterator start);

  virtual void Print (std::ostream &os) const;

  bool GetExtensionHeaderFlag () const;

  uint16_t GetLength () const;

  uint8_t GetMessageType () const;

  uint8_t GetNPduNumber () const;

  bool GetNPduNumberFlag () const;

  uint8_t GetNextExtensionType () const;

  bool GetProtocolType () const;

  uint16_t GetSequenceNumber () const;

  bool GetSequenceNumberFlag () const;

  uint32_t GetTeid () const;

  uint8_t GetVersion () const;

  void SetExtensionHeaderFlag (bool m_extensionHeaderFlag);

  void SetLength (uint16_t m_length);

  void SetMessageType (uint8_t m_messageType);

  void SetNPduNumber (uint8_t m_nPduNumber);

  void SetNPduNumberFlag (bool m_nPduNumberFlag);

  void SetNextExtensionType (uint8_t m_nextExtensionType);

  void SetProtocolType (bool m_protocolType);

  void SetSequenceNumber (uint16_t m_sequenceNumber);

  void SetSequenceNumberFlag (bool m_sequenceNumberFlag);

  void SetTeid (uint32_t m_teid);

  void SetVersion (uint8_t m_version);

  bool operator == (const GtpuHeader& b) const;

private:

  /**

   * This field is used to determine the version of the GTPU-U protocol. The version number shall be set to 1.

   */

  uint8_t m_version;   // really a 3 uint3_t

  /**

   * This bit is used as a protocol discriminator between GTP (when PT is '1') and GTP' (when

   * PT is '0').

   */

  bool m_protocolType;

  /**

   * This flag indicates the presence of a meaningful value of the Next Extension Header

   * field. When it is set to '0', the Next Extension Header field either is not present

   * or, if present, shall not be interpreted. When it is set to '1', the Next Extension

   *  Header field is present, and shall be interpreted

   */

  bool m_extensionHeaderFlag;

  /**

   * This flag indicates the presence of a meaningful value of the Sequence Number field.

   * When it is set to '0', the Sequence Number field either is not present or, if present,

   * shall not be interpreted. When it is set to '1', the Sequence Number field is present,

   * and shall be interpreted

   */

  bool m_sequenceNumberFlag;

  /**

   * This flag indicates the presence of a meaningful value of the N-PDU Number field.

   * When it is set to '0', the N-PDU Number field either is not present, or, if present,

   * shall not be interpreted. When it is set to '1', the N-PDU Number field is present,

   * and shall be interpreted

   */

  bool m_nPduNumberFlag;

  /**

   *  This field indicates the type of GTP-U message

   */

  uint8_t m_messageType;

  /**

   *  This field indicates the length in octets of the payload, i.e. the rest of the packet

   *  following the mandatory part of the GTP header (that is the first 8 octets).

   *  The Sequence Number, the N-PDU Number or any Extension headers shall be considered

   *  to be part of the payload, i.e. included in the length count

   */

  uint16_t m_length;

  /**

   * This field unambiguously identifies a tunnel endpoint in the receiving GTP-U

   * protocol entity. The receiving end side of a GTP tunnel locally assigns the

   * TEID value the transmitting side has to use.

   */

  uint32_t m_teid;

  /**

   * If Sequence Number field is used for G-PDUs (T-PDUs+headers), an increasing

   * sequence number for T-PDUs is transmitted via GTP-U tunnels, when transmission

   * order must be preserved

   */

  uint16_t m_sequenceNumber;

  /**

   * This field is used at the Inter SGSN Routeing Area Update procedure and some

   * inter-system handover procedures (e.g. between 2G and 3G radio access networks).

   * This field is used to co-ordinate the data transmission for acknowledged mode

   * of communication between the MS and the SGSN

   */

  uint8_t m_nPduNumber;

  /**

   * This field defines the type of Extension Header that follows this field in

   * the GTP-PDU

   */

  uint8_t m_nextExtensionType;

};

} // namespace ns3

#endif /* EPS_GTPU_V1_H */