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

/*

 * 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_SOCKET_IMPL_H

#define TCP_SOCKET_IMPL_H

#include <stdint.h>

#include <queue>

#include "ns3/callback.h"

#include "ns3/traced-value.h"

#include "ns3/tcp-socket.h"

#include "ns3/ptr.h"

#include "ns3/ipv4-address.h"

#include "ns3/event-id.h"

#include "tcp-typedefs.h"

#include "pending-data.h"

#include "sequence-number.h"

#include "rtt-estimator.h"

namespace ns3 {

class Ipv4EndPoint;

class Node;

class Packet;

class TcpL4Protocol;

class TcpHeader;

/**

 * \ingroup socket

 * \ingroup tcp

 *

 * \brief An implementation of a stream socket using TCP.

 *

 * This class contains an implementation of TCP Tahoe, as well as a sockets

 * interface for talking to TCP.  Features include connection orientation,

 * reliability through cumulative acknowledgements, congestion and flow 

 * control.  Finite send buffer semantics are modeled, but as of yet, finite

 * receive buffer modelling is unimplemented.

 *

 * The closedown of these sockets is as of yet not compliant with the relevent

 * RFCs, i.e. the FIN handshaking isn't correct.  While this is visible at the

 * PCAP tracing level, it has no effect on the statistics users are interested

 * in, i.e. throughput, delay, etc. of actual payload data.

 *

 * Asynchronous callbacks to provide notifications to higher layers that a 

 * protocol event has occured, such as space freeing up in the send buffer

 * or new data arriving in the receive buffer.

 */

class TcpSocketImpl : public TcpSocket

{

public:

  static TypeId GetTypeId (void);

  /**

   * Create an unbound tcp socket.

   */

  TcpSocketImpl ();

  TcpSocketImpl (const TcpSocketImpl& sock);

  virtual ~TcpSocketImpl ();

  void SetNode (Ptr<Node> node);

  void SetTcp (Ptr<TcpL4Protocol> tcp);

  void SetRtt (Ptr<RttEstimator> rtt);

  virtual enum SocketErrno GetErrno (void) const;

  virtual Ptr<Node> GetNode (void) const;

  virtual int Bind (void);

  virtual int Bind (const Address &address);

  virtual int Close (void);

  virtual int ShutdownSend (void);

  virtual int ShutdownRecv (void);

  virtual int Connect(const Address &address);

  virtual int Listen(void);

  virtual uint32_t GetTxAvailable (void) const;

  virtual int Send (Ptr<Packet> p, uint32_t flags);

  virtual int SendTo(Ptr<Packet> p, uint32_t flags, const Address &toAddress);

  virtual uint32_t GetRxAvailable (void) const;

  virtual Ptr<Packet> Recv (uint32_t maxSize, uint32_t flags);

  virtual Ptr<Packet> RecvFrom (uint32_t maxSize, uint32_t flags,

    Address &fromAddress);

  virtual int GetSockName (Address &address) const; 

private:

  friend class Tcp;

  // invoked by Tcp class

  int FinishBind (void);

  void ForwardUp (Ptr<Packet> p, Ipv4Address ipv4, uint16_t port);

  void Destroy (void);

  int DoSendTo (Ptr<Packet> p, const Address &daddr);

  int DoSendTo (Ptr<Packet> p, Ipv4Address daddr, uint16_t dport);

  void SendEmptyPacket(uint8_t flags);

  //methods for state

  bool ProcessAction (Actions_t a);

  bool ProcessAction (Actions_t a, const TcpHeader& tcpHeader,

                      Ipv4Address saddr, Ipv4Address daddr);

  bool ProcessPacketAction (Actions_t a, Ptr<Packet> p,

                                       const TcpHeader& tcpHeader,

                                       const Address& fromAddress);

  Actions_t ProcessEvent (Events_t e);

  bool SendPendingData(bool withAck = false);

  void CompleteFork(Ptr<Packet>, const TcpHeader&, const Address& fromAddress);

  void ConnectionSucceeded();

  //methods for window management

  virtual uint32_t  UnAckDataCount(); // Return count of number of unacked bytes

  virtual uint32_t  BytesInFlight();  // Return total bytes in flight

  virtual uint32_t  Window();         // Return window size (integer)

  virtual uint32_t  AvailableWindow();// Return unfilled portion of window

  //methods for Rx buffer management

  uint32_t RxBufferFreeSpace();

  uint16_t AdvertisedWindowSize();

  // Manage data tx/rx

  void NewRx (Ptr<Packet>, const TcpHeader&, const Address&);

  void RxBufFinishInsert (SequenceNumber);

  // XXX This should be virtual and overridden

  Ptr<TcpSocketImpl> Copy ();

  void NewAck (SequenceNumber seq); 

  // XXX This should be virtual and overridden

  void DupAck (const TcpHeader& t, uint32_t count); 

  void ReTxTimeout ();

  void DelAckTimeout ();

  void LastAckTimeout ();

  void PersistTimeout ();

  void Retransmit ();

  void CommonNewAck (SequenceNumber seq, bool skipTimer = false);

  // attribute related

  virtual void SetSndBufSize (uint32_t size);

  virtual uint32_t GetSndBufSize (void) const;

  virtual void SetRcvBufSize (uint32_t size);

  virtual uint32_t GetRcvBufSize (void) const;

  virtual void SetSegSize (uint32_t size);

  virtual uint32_t GetSegSize (void) const;

  virtual void SetSSThresh (uint32_t threshold);

  virtual uint32_t GetSSThresh (void) const;

  virtual void SetInitialCwnd (uint32_t cwnd);

  virtual uint32_t GetInitialCwnd (void) const;

  virtual void SetConnTimeout (Time timeout);

  virtual Time GetConnTimeout (void) const;

  virtual void SetConnCount (uint32_t count);

  virtual uint32_t GetConnCount (void) const;

  virtual void SetDelAckTimeout (Time timeout);

  virtual Time GetDelAckTimeout (void) const;

  virtual void SetDelAckMaxCount (uint32_t count);

  virtual uint32_t GetDelAckMaxCount (void) const;

  bool m_skipRetxResched;

  uint32_t m_dupAckCount;

  EventId m_retxEvent;

  EventId m_lastAckEvent;

  EventId m_delAckEvent;

  uint32_t m_delAckCount;

  uint32_t m_delAckMaxCount;

  Time m_delAckTimeout;

  Ipv4EndPoint *m_endPoint;

  Ptr<Node> m_node;

  Ptr<TcpL4Protocol> m_tcp;

  Ipv4Address m_remoteAddress;

  uint16_t m_remotePort;

  //these two are so that the socket/endpoint cloning works

  Ipv4Address m_localAddress;

  uint16_t m_localPort;

  enum SocketErrno m_errno;

  bool m_shutdownSend;

  bool m_shutdownRecv;

  bool m_connected;

  //manage the state infomation

  States_t m_state;

  bool m_closeNotified;

  bool m_closeRequestNotified;

  bool m_closeOnEmpty;

  bool m_pendingClose;

  //sequence info, sender side

  SequenceNumber m_nextTxSequence;

  SequenceNumber m_highTxMark;

  SequenceNumber m_highestRxAck;

  SequenceNumber m_lastRxAck;

  //sequence info, reciever side

  SequenceNumber m_nextRxSequence; //next expected sequence

  //Rx buffer

  UnAckData_t m_bufferedData; //buffer which sorts out of sequence data

  //Rx buffer state

  uint32_t m_rxAvailable; // amount of data available for reading through Recv

  uint32_t m_rxBufSize; //size in bytes of the data in the rx buf

  //note that these two are not the same: rxAvailbale is the number of

  //contiguous sequenced bytes that can be read, rxBufSize is the TOTAL size

  //including out of sequence data, such that m_rxAvailable <= m_rxBufSize

  //this is kind of the tx buffer

  PendingData* m_pendingData;

  SequenceNumber m_firstPendingSequence;

  // Window management

  uint32_t                       m_segmentSize;          //SegmentSize

  uint32_t                       m_rxWindowSize;         //Flow control window

  TracedValue<uint32_t>          m_cWnd;                 //Congestion window

  uint32_t                       m_ssThresh;             //Slow Start Threshold

  uint32_t                       m_initialCWnd;          //Initial cWnd value

  //persist timer management

  Time                           m_persistTime;

  EventId                        m_persistEvent;

  // Round trip time estimation

  Ptr<RttEstimator> m_rtt;

  Time m_lastMeasuredRtt;

  // Timer-related members

  Time              m_cnTimeout; 

  uint32_t          m_cnCount;

  // Attributes

  uint32_t m_sndBufSize;   // buffer limit for the outgoing queue

  uint32_t m_rxBufMaxSize;   // maximum receive socket buffer size

};

}//namespace ns3

#endif /* TCP_SOCKET_IMPL_H */