/*

 * Copyright (c) 2007 Georgia Tech Research Corporation

 *

 * 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: Raj Bhattacharjea <raj.b@gatech.edu>

 */

#ifndef TCP_HEADER_H

#define TCP_HEADER_H

#include <stdint.h>

#include "ns3/header.h"

#include "ns3/buffer.h"

#include "ns3/tcp-socket-factory.h"

#include "ns3/ipv4-address.h"

#include "ns3/sequence-number.h"

namespace ns3 {

/**

 * \ingroup tcp

 * \brief Header for the Transmission Control Protocol

 *

 * This class has fields corresponding to those in a network TCP header

 * (port numbers, sequence and acknowledgement numbers, flags, etc) as well

 * as methods for serialization to and deserialization from a byte buffer.

 */

class TcpHeader : public Header 

{

public:

  TcpHeader ();

  virtual ~TcpHeader ();

  /**

   * \brief Enable checksum calculation for TCP (XXX currently has no effect)

   */

  void EnableChecksums (void);

//Setters

/**

 * \param port The source port for this TcpHeader

 */

  void SetSourcePort (uint16_t port);

  /**

   * \param port the destination port for this TcpHeader

   */

  void SetDestinationPort (uint16_t port);

  /**

   * \param sequenceNumber the sequence number for this TcpHeader

   */

  void SetSequenceNumber (SequenceNumber32 sequenceNumber);

  /**

   * \param ackNumber the ACK number for this TcpHeader

   */

  void SetAckNumber (SequenceNumber32 ackNumber);

  /**

   * \param length the length of this TcpHeader

   */

  void SetLength (uint8_t length);

  /**

   * \param flags the flags for this TcpHeader

   */

  void SetFlags (uint8_t flags);

  /**

   * \param windowSize the window size for this TcpHeader

   */

  void SetWindowSize (uint16_t windowSize);

  /**

   * \param urgentPointer the urgent pointer for this TcpHeader

   */

  void SetUrgentPointer (uint16_t urgentPointer);

//Getters

/**

 * \return The source port for this TcpHeader

 */

  uint16_t GetSourcePort () const;

  /**

   * \return the destination port for this TcpHeader

   */

  uint16_t GetDestinationPort () const;

  /**

   * \return the sequence number for this TcpHeader

   */

  SequenceNumber32 GetSequenceNumber () const;

  /**

   * \return the ACK number for this TcpHeader

   */

  SequenceNumber32 GetAckNumber () const;

  /**

   * \return the length of this TcpHeader

   */

  uint8_t  GetLength () const;

  /**

   * \return the flags for this TcpHeader

   */

  uint8_t  GetFlags () const;

  /**

   * \return the window size for this TcpHeader

   */

  uint16_t GetWindowSize () const;

  /**

   * \return the urgent pointer for this TcpHeader

   */

  uint16_t GetUrgentPointer () const;

  /**

   * \param source the ip source to use in the underlying

   *        ip packet.

   * \param destination the ip destination to use in the

   *        underlying ip packet.

   * \param protocol the protocol number to use in the underlying

   *        ip packet.

   *

   * If you want to use tcp checksums, you should call this

   * method prior to adding the header to a packet.

   */

  void InitializeChecksum (Ipv4Address source, 

                           Ipv4Address destination,

                           uint8_t protocol);

  typedef enum { NONE = 0, FIN = 1, SYN = 2, RST = 4, PSH = 8, ACK = 16, 

                 URG = 32} Flags_t;

  static TypeId GetTypeId (void);

  virtual TypeId GetInstanceTypeId (void) const;

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

  virtual uint32_t GetSerializedSize (void) const;

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

  virtual uint32_t Deserialize (Buffer::Iterator start);

  /**

   * \brief Is the TCP checksum correct ?

   * \returns true if the checksum is correct, false otherwise.

   */

  bool IsChecksumOk (void) const;

private:

  uint16_t CalculateHeaderChecksum (uint16_t size) const;

  uint16_t m_sourcePort;

  uint16_t m_destinationPort;

  SequenceNumber32 m_sequenceNumber;

  SequenceNumber32 m_ackNumber;

  uint8_t m_length; // really a uint4_t

  uint8_t m_flags;      // really a uint6_t

  uint16_t m_windowSize;

  uint16_t m_urgentPointer;

  Ipv4Address m_source;

  Ipv4Address m_destination;

  uint8_t m_protocol;

  uint16_t m_initialChecksum;

  bool m_calcChecksum;

  bool m_goodChecksum;

};

}; // namespace ns3

#endif /* TCP_HEADER */