/* -*-  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>

 */

#include "ns3/node.h"

#include "ns3/inet-socket-address.h"

#include "ns3/log.h"

#include "ns3/ipv4.h"

#include "tcp-socket.h"

#include "tcp-l4-protocol.h"

#include "ipv4-end-point.h"

#include "ipv4-l4-demux.h"

#include "ns3/simulation-singleton.h"

#include "tcp-typedefs.h"

#include "ns3/simulator.h"

#include "ns3/packet.h"

#include "ns3/default-value.h"

#include <algorithm>

NS_LOG_COMPONENT_DEFINE ("TcpSocket");

using namespace std;

namespace ns3 {

TcpSocket::TcpSocket (Ptr<Node> node, Ptr<TcpL4Protocol> tcp)

  : m_skipRetxResched (false),

    m_dupAckCount (0),

    m_endPoint (0),

    m_node (node),

    m_tcp (tcp),

    m_errno (ERROR_NOTERROR),

    m_shutdownSend (false),

    m_shutdownRecv (false),

    m_connected (false),

    m_state (CLOSED),

    m_closeNotified (false),

    m_closeRequestNotified (false),

    m_closeOnEmpty (false),

    m_pendingClose (false),

    m_nextTxSequence (0),

    m_highTxMark (0),

    m_highestRxAck (0),

    m_lastRxAck (0),

    m_nextRxSequence (0),

    m_pendingData (0),

    m_segmentSize (Tcp::defaultSegSize.GetValue()),

    m_rxWindowSize (Tcp::defaultAdvWin.GetValue()),

    m_advertisedWindowSize (Tcp::defaultAdvWin.GetValue()),

    m_cWnd (Tcp::defaultInitialCWnd.GetValue() * m_segmentSize),

    m_ssThresh (Tcp::defaultSSThresh.GetValue()),

    m_initialCWnd (Tcp::defaultInitialCWnd.GetValue()),

    m_rtt (RttEstimator::CreateDefault()),

    m_lastMeasuredRtt (Seconds(0.0)),

    m_cnTimeout (Seconds (Tcp::defaultConnTimeout.GetValue ())),

    m_cnCount (Tcp::defaultConnCount.GetValue ())

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this<<node<<tcp);

}

TcpSocket::~TcpSocket ()

{

  NS_LOG_FUNCTION;

  m_node = 0;

  if (m_endPoint != 0)

    {

      NS_ASSERT (m_tcp != 0);

      /**

       * Note that this piece of code is a bit tricky:

       * when DeAllocate is called, it will call into

       * Ipv4EndPointDemux::Deallocate which triggers

       * a delete of the associated endPoint which triggers

       * in turn a call to the method ::Destroy below

       * will will zero the m_endPoint field.

       */

      NS_ASSERT (m_endPoint != 0);

      m_tcp->DeAllocate (m_endPoint);

      NS_ASSERT (m_endPoint == 0);

    }

  m_tcp = 0;

  delete m_pendingData; //prevents leak

  m_pendingData = 0;

}

enum Socket::SocketErrno

TcpSocket::GetErrno (void) const

{

  NS_LOG_FUNCTION;

  return m_errno;

}

Ptr<Node>

TcpSocket::GetNode (void) const

{

  NS_LOG_FUNCTION;

  return m_node;

}

void 

TcpSocket::Destroy (void)

{

  NS_LOG_FUNCTION;

  m_node = 0;

  m_endPoint = 0;

  m_tcp = 0;

  m_retxEvent.Cancel ();

}

int

TcpSocket::FinishBind (void)

{

  NS_LOG_FUNCTION;

  if (m_endPoint == 0)

    {

      return -1;

    }

  m_endPoint->SetRxCallback (MakeCallback (&TcpSocket::ForwardUp, this));

  m_endPoint->SetDestroyCallback (MakeCallback (&TcpSocket::Destroy, this));

  return 0;

}

int

TcpSocket::Bind (void)

{

  NS_LOG_FUNCTION;

  m_endPoint = m_tcp->Allocate ();

  return FinishBind ();

}

int 

TcpSocket::Bind (const Address &address)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this<<address);

  if (!InetSocketAddress::IsMatchingType (address))

    {

      return ERROR_INVAL;

    }

  InetSocketAddress transport = InetSocketAddress::ConvertFrom (address);

  Ipv4Address ipv4 = transport.GetIpv4 ();

  uint16_t port = transport.GetPort ();

  Ipv4Address localInterface = Ipv4Address::GetAny ();

  if (ipv4 != Ipv4Address::GetAny ())

    {

      Ptr<Ipv4> ipv4_api = m_node->GetObject<Ipv4> ();

      // Assert that the given address matches an existing local interface

      NS_ASSERT (ipv4_api->FindInterfaceForAddr (ipv4) != 0);

      localInterface = ipv4;

    }

  if (ipv4 == Ipv4Address::GetAny () && port == 0)

    {

      m_endPoint = m_tcp->Allocate ();

      NS_LOG_LOGIC ("TcpSocket "<<this<<" got an endpoint: "<<m_endPoint);

    }

  else if (ipv4 == Ipv4Address::GetAny () && port != 0)

    {

      m_endPoint = m_tcp->Allocate (port);

      NS_LOG_LOGIC ("TcpSocket "<<this<<" got an endpoint: "<<m_endPoint);

    }

  else if (ipv4 != Ipv4Address::GetAny () && port == 0)

    {

      m_endPoint = m_tcp->Allocate (ipv4, localInterface);

      NS_LOG_LOGIC ("TcpSocket "<<this<<" got an endpoint: "<<m_endPoint);

    }

  else if (ipv4 != Ipv4Address::GetAny () && port != 0)

    {

      m_endPoint = m_tcp->Allocate (ipv4, port, localInterface);

      NS_LOG_LOGIC ("TcpSocket "<<this<<" got an endpoint: "<<m_endPoint);

    }

  return FinishBind ();

}

int 

TcpSocket::ShutdownSend (void)

{

  NS_LOG_FUNCTION;

  m_shutdownSend = true;

  return 0;

}

int 

TcpSocket::ShutdownRecv (void)

{

  NS_LOG_FUNCTION;

  m_shutdownRecv = false;

  return 0;

}

int

TcpSocket::Close (void)

{

  NS_LOG_FUNCTION;

  if (m_state == CLOSED) 

    {

      return -1;

    }

  Actions_t action  = ProcessEvent (APP_CLOSE);

  if (m_pendingData)

    {

      if (action == FIN_TX && m_pendingData->Size () != 0 )

        {

          m_closeOnEmpty = true;

          return 0;

        }

    }

  ProcessAction (action);

  ShutdownSend ();

  return 0;

}

int

TcpSocket::Connect (const Address & address)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << address);

  if (m_endPoint == 0)

    {

      if (Bind () == -1)

        {

          NS_ASSERT (m_endPoint == 0);

          return -1;

        }

      NS_ASSERT (m_endPoint != 0);

    }

  InetSocketAddress transport = InetSocketAddress::ConvertFrom (address);

  m_defaultAddress = transport.GetIpv4 ();

  m_defaultPort = transport.GetPort ();

  uint32_t localIfIndex;

  Ptr<Ipv4> ipv4 = m_node->GetObject<Ipv4> ();

  if (ipv4->GetIfIndexForDestination (m_defaultAddress, localIfIndex))

    {

      m_endPoint->SetLocalAddress (ipv4->GetAddress (localIfIndex));

    }

  else

    {

      m_errno = ERROR_NOROUTETOHOST;

      return -1;

    }

  Actions_t action = ProcessEvent (APP_CONNECT);

  bool success = ProcessAction (action);

  if (success) 

    {

      return 0;

    }

  return -1;

}

int 

TcpSocket::Send (const Ptr<Packet> p) //p here is just data, no headers

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << p);

  if (m_state == ESTABLISHED || m_state == SYN_SENT || m_state == CLOSE_WAIT)

    { // Ok to buffer some data to send

      if (!m_pendingData)

        {

          m_pendingData = new PendingData (0);   // Create if non-existent

          m_firstPendingSequence = m_nextTxSequence; // Note seq of first

        }

      //PendingData::Add always copies the data buffer, never modifies

      m_pendingData->Add (p->GetSize (), p->PeekData ());

      Actions_t action = ProcessEvent (APP_SEND);

      if (!ProcessAction (action)) 

        {

          return -1; // Failed, return zero

        }

      return p->GetSize ();

    }

  else

    {

      m_errno = ERROR_NOTCONN;

      return -1;

    }

}

int TcpSocket::Send (const uint8_t* buf, uint32_t size)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << buf << size);

  if (m_state == ESTABLISHED || m_state == SYN_SENT || m_state == CLOSE_WAIT)

    { // Ok to buffer some data to send

      if (!m_pendingData)

      {

        m_pendingData = new PendingData ();   // Create if non-existent

        m_firstPendingSequence = m_nextTxSequence; // Note seq of first

      }

      //PendingData::Add always copies the data buffer, never modifies

      m_pendingData->Add (size,buf);

      Actions_t action = ProcessEvent (APP_SEND);

      if (!ProcessAction (action)) 

        {

          return -1; // Failed, return zero

        }

      return size;

    }

  else

  {

    m_errno = ERROR_NOTCONN;

    return -1;

  }

}

int TcpSocket::DoSendTo (Ptr<Packet> p, const Address &address)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << p << address);

  InetSocketAddress transport = InetSocketAddress::ConvertFrom (address);

  Ipv4Address ipv4 = transport.GetIpv4 ();

  uint16_t port = transport.GetPort ();

  return DoSendTo (p, ipv4, port);

}

int TcpSocket::DoSendTo (Ptr<Packet> p, Ipv4Address ipv4, uint16_t port)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << p << ipv4 << port);

  if (m_endPoint == 0)

    {

      if (Bind () == -1)

	{

          NS_ASSERT (m_endPoint == 0);

	  return -1;

	}

      NS_ASSERT (m_endPoint != 0);

    }

  if (m_shutdownSend)

    {

      m_errno = ERROR_SHUTDOWN;

      return -1;

    }

  m_tcp->Send (p, m_endPoint->GetLocalAddress (), ipv4,

                  m_endPoint->GetLocalPort (), port);

  NotifyDataSent (p->GetSize ());

  return 0;

}

int 

TcpSocket::SendTo (const Address &address, Ptr<Packet> p)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << address << p);

  if (!m_connected)

    {

      m_errno = ERROR_NOTCONN;

      return -1;

    }

  else

    {

      return Send (p); //drop the address according to BSD manpages

    }

}

int

TcpSocket::Listen (uint32_t q)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << q);

  Actions_t action = ProcessEvent (APP_LISTEN);

  ProcessAction (action);

  return 0;

}

void

TcpSocket::ForwardUp (Ptr<Packet> packet, Ipv4Address ipv4, uint16_t port)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << packet << ipv4 << port);

  if (m_shutdownRecv)

    {

      return;

    }

  TcpHeader tcpHeader;

  packet->RemoveHeader (tcpHeader);

  if (tcpHeader.GetFlags () & TcpHeader::ACK)

    {

      Time m = m_rtt->AckSeq (tcpHeader.GetAckNumber () );

      if (m != Seconds (0.0))

        {

          m_lastMeasuredRtt = m;

        }

    }

  Events_t event = SimulationSingleton<TcpStateMachine>::Get ()->FlagsEvent (tcpHeader.GetFlags () );

  Actions_t action = ProcessEvent (event); //updates the state

  Address address = InetSocketAddress (ipv4, port);

  ProcessPacketAction (action, packet, tcpHeader, address);

}

Actions_t TcpSocket::ProcessEvent (Events_t e)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << e);

  States_t saveState = m_state;

  NS_LOG_LOGIC ("TcpSocket " << this << " processing event " << e);

  // simulation singleton is a way to get a single global static instance of a

  // class intended to be a singleton; see simulation-singleton.h

  SA stateAction = SimulationSingleton<TcpStateMachine>::Get ()->Lookup (m_state,e);

  // debug

  if (stateAction.action == RST_TX)

    {

      NS_LOG_LOGIC ("TcpSocket " << this << " sending RST from state "

              << saveState << " event " << e);

    }

  bool needCloseNotify = (stateAction.state == CLOSED && m_state != CLOSED 

    && e != TIMEOUT);

  m_state = stateAction.state;

  NS_LOG_LOGIC ("TcpSocket " << this << " moved from state " << saveState 

    << " to state " <<m_state);

  NS_LOG_LOGIC ("TcpSocket " << this << " pendingData " << m_pendingData);

  if (saveState == SYN_SENT && m_state == ESTABLISHED)

    // this means the application side has completed its portion of 

    // the handshaking

    {

      NotifyConnectionSucceeded ();

      m_connected = true;

      m_endPoint->SetPeer (m_defaultAddress, m_defaultPort);

      NS_LOG_LOGIC ("TcpSocket " << this << " Connected!");

    }

  if (needCloseNotify && !m_closeNotified)

    {

      NS_LOG_LOGIC ("TcpSocket " << this << " transition to CLOSED from " 

               << m_state << " event " << e << " closeNot " << m_closeNotified

               << " action " << stateAction.action);

      NotifyCloseCompleted ();

      m_closeNotified = true;

      NS_LOG_LOGIC ("TcpSocket " << this << " calling Closed from PE"

              << " origState " << saveState

              << " event " << e);

      NS_LOG_LOGIC ("TcpSocket " << this << " transition to CLOSED from "

          << m_state << " event " << e

          << " set CloseNotif ");

    }

  return stateAction.action;

}

void TcpSocket::SendEmptyPacket (uint8_t flags)

{

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << flags);

  Ptr<Packet> p = Create<Packet> ();

  TcpHeader header;

  header.SetFlags (flags);

  header.SetSequenceNumber (m_nextTxSequence);

  header.SetAckNumber (m_nextRxSequence);

  header.SetSourcePort (m_endPoint->GetLocalPort ());

  header.SetDestinationPort (m_defaultPort);

  header.SetWindowSize (m_advertisedWindowSize);

  m_tcp->SendPacket (p, header, m_endPoint->GetLocalAddress (), 

    m_defaultAddress);

  Time rto = m_rtt->RetransmitTimeout ();

  if (flags & TcpHeader::SYN)

    {

      rto = m_cnTimeout;

      m_cnTimeout = m_cnTimeout + m_cnTimeout;

      m_cnCount--;

    }

  if (m_retxEvent.IsExpired () ) //no outstanding timer

  {

    NS_LOG_LOGIC ("Schedule retransmission timeout at time " 

          << Simulator::Now ().GetSeconds () << " to expire at time " 

          << (Simulator::Now () + rto).GetSeconds ());

    m_retxEvent = Simulator::Schedule (rto, &TcpSocket::ReTxTimeout, this);

  }

}

bool TcpSocket::ProcessAction (Actions_t a)

{ // These actions do not require a packet or any TCP Headers

  NS_LOG_FUNCTION;

  NS_LOG_PARAMS (this << a);

  switch (a)

  {

    case NO_ACT:

      NS_LOG_LOGIC ("TcpSocket " << this <<" Action: NO_ACT");

      break;

    case ACK_TX:

      SendEmptyPacket (TcpHeader::ACK);

      break;

    case ACK_TX_1:

      NS_ASSERT (false); // This should be processed in ProcessPacketAction

      break;

    case RST_TX:

      NS_LOG_LOGIC ("TcpSocket " << this <<" Action RST_TX");

      SendEmptyPacket (TcpHeader::RST);

      break;

    case SYN_TX:

      NS_LOG_LOGIC ("TcpSocket " << this <<" Action SYN_TX");

      // TCP SYN Flag consumes one byte

      // is the above correct? we're SENDING a syn, not acking back -- Raj

      // commented out for now

      // m_nextTxSequence+= 1;

      SendEmptyPacket (TcpHeader::SYN);

      break;

    case SYN_ACK_TX:

      NS_LOG_LOGIC ("TcpSocket " << this <<" Action SYN_ACK_TX");

      SendEmptyPacket (TcpHeader::SYN | TcpHeader::ACK);

      break;

    case FIN_TX:

      NS_LOG_LOGIC ("TcpSocket " << this <<" Action FIN_TX");

      SendEmptyPacket (TcpHeader::FIN);

      break;

    case FIN_ACK_TX:

      NS_LOG_LOGIC ("TcpSocket " << this <<" Action FIN_ACK_TX");

      SendEmptyPacket (TcpHeader::FIN | TcpHeader::ACK);

      break;

    case NEW_ACK: