/* -*-  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-impl.h"

#include "tcp-l4-protocol.h"

#include "ipv4-end-point.h"

#include "ns3/simulation-singleton.h"

#include "tcp-typedefs.h"

#include "ns3/simulator.h"

#include "ns3/packet.h"

#include "ns3/uinteger.h"

#include "ns3/trace-source-accessor.h"

#include <algorithm>

NS_LOG_COMPONENT_DEFINE ("TcpSocketImpl");

using namespace std;

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (TcpSocketImpl);

TypeId

TcpSocketImpl::GetTypeId ()

{

  static TypeId tid = TypeId("ns3::TcpSocketImpl")

    .SetParent<TcpSocket> ()

    .AddTraceSource ("CongestionWindow",

                     "The TCP connection's congestion window",

                     MakeTraceSourceAccessor (&TcpSocketImpl::m_cWnd))

    ;

  return tid;

}

  TcpSocketImpl::TcpSocketImpl ()

  : m_skipRetxResched (false),

    m_dupAckCount (0),

    m_delAckCount (0),

    m_endPoint (0),

    m_node (0),

    m_tcp (0),

    m_localAddress (Ipv4Address::GetZero ()),

    m_localPort (0),

    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_rxAvailable (0),

    m_rxBufSize (0),

    m_pendingData (0),

    m_rxWindowSize (0),

    m_persistTime (Seconds(6)), //XXX hook this into attributes?

    m_rtt (0),

    m_lastMeasuredRtt (Seconds(0.0))

{

  NS_LOG_FUNCTION (this);

}

TcpSocketImpl::TcpSocketImpl(const TcpSocketImpl& sock)

  : TcpSocket(sock), //copy object::m_tid, copy socket::callbacks

    m_skipRetxResched (sock.m_skipRetxResched),

    m_dupAckCount (sock.m_dupAckCount),

    m_delAckCount (0),

    m_delAckMaxCount (sock.m_delAckMaxCount),

    m_delAckTimeout (sock.m_delAckTimeout),

    m_endPoint (0),

    m_node (sock.m_node),

    m_tcp (sock.m_tcp),

    m_remoteAddress (sock.m_remoteAddress),

    m_remotePort (sock.m_remotePort),

    m_localAddress (sock.m_localAddress),

    m_localPort (sock.m_localPort),

    m_errno (sock.m_errno),

    m_shutdownSend (sock.m_shutdownSend),

    m_shutdownRecv (sock.m_shutdownRecv),

    m_connected (sock.m_connected),

    m_state (sock.m_state),

    m_closeNotified (sock.m_closeNotified),

    m_closeRequestNotified (sock.m_closeRequestNotified),

    m_closeOnEmpty (sock.m_closeOnEmpty),

    m_pendingClose (sock.m_pendingClose),

    m_nextTxSequence (sock.m_nextTxSequence),

    m_highTxMark (sock.m_highTxMark),

    m_highestRxAck (sock.m_highestRxAck),

    m_lastRxAck (sock.m_lastRxAck),

    m_nextRxSequence (sock.m_nextRxSequence),

    m_rxAvailable (0),

    m_rxBufSize (0),

    m_pendingData (0),

    m_segmentSize (sock.m_segmentSize),

    m_rxWindowSize (sock.m_rxWindowSize),

    m_cWnd (sock.m_cWnd),

    m_ssThresh (sock.m_ssThresh),

    m_initialCWnd (sock.m_initialCWnd),

    m_persistTime (sock.m_persistTime),

    m_rtt (0),

    m_lastMeasuredRtt (Seconds(0.0)),

    m_cnTimeout (sock.m_cnTimeout),

    m_cnCount (sock.m_cnCount),

    m_sndBufSize (sock.m_sndBufSize),

    m_rxBufMaxSize(sock.m_rxBufMaxSize)

{

  NS_LOG_FUNCTION_NOARGS ();

  NS_LOG_LOGIC("Invoked the copy constructor");

  //copy the pending data if necessary

  if(sock.m_pendingData)

    {

      m_pendingData = sock.m_pendingData->Copy();

    }

  //copy the rtt if necessary

  if (sock.m_rtt)

    {

      m_rtt = sock.m_rtt->Copy();

    }

  //null out the socket base class callbacks,

  //make user of the socket register this explicitly

  Callback<void, Ptr< Socket > > vPS =

      MakeNullCallback<void, Ptr<Socket> > ();

  Callback<void, Ptr<Socket>, const Address &> vPSA =

      MakeNullCallback<void, Ptr<Socket>, const Address &> ();

  Callback<void, Ptr<Socket>, uint32_t> vPSUI =

      MakeNullCallback<void, Ptr<Socket>, uint32_t> ();

  SetConnectCallback (vPS, vPS);

  SetDataSentCallback (vPSUI);

  SetSendCallback (vPSUI);

  SetRecvCallback (vPS);

  //can't "copy" the endpoint just yes, must do this when we know the peer info

  //too; this is in SYN_ACK_TX

}

TcpSocketImpl::~TcpSocketImpl ()

{

  NS_LOG_FUNCTION(this);

  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;

}

void

TcpSocketImpl::SetNode (Ptr<Node> node)

{

  m_node = node;

  // Initialize some variables 

  m_cWnd = m_initialCWnd * m_segmentSize;

}

void 

TcpSocketImpl::SetTcp (Ptr<TcpL4Protocol> tcp)

{

  m_tcp = tcp;

}

void 

TcpSocketImpl::SetRtt (Ptr<RttEstimator> rtt)

{

  m_rtt = rtt;

}

enum Socket::SocketErrno

TcpSocketImpl::GetErrno (void) const

{

  NS_LOG_FUNCTION_NOARGS ();

  return m_errno;

}

Ptr<Node>

TcpSocketImpl::GetNode (void) const

{

  NS_LOG_FUNCTION_NOARGS ();

  return m_node;

}

void 

TcpSocketImpl::Destroy (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_node = 0;

  m_endPoint = 0;

  m_tcp = 0;

  NS_LOG_LOGIC (this<<" Cancelled ReTxTimeout event which was set to expire at "

                << (Simulator::Now () + 

                Simulator::GetDelayLeft (m_retxEvent)).GetSeconds());

  m_retxEvent.Cancel ();

}

int

TcpSocketImpl::FinishBind (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  if (m_endPoint == 0)

    {

      return -1;

    }

  m_endPoint->SetRxCallback (MakeCallback (&TcpSocketImpl::ForwardUp, Ptr<TcpSocketImpl>(this)));

  m_endPoint->SetDestroyCallback (MakeCallback (&TcpSocketImpl::Destroy, Ptr<TcpSocketImpl>(this)));

  m_localAddress = m_endPoint->GetLocalAddress ();

  m_localPort = m_endPoint->GetLocalPort ();

  return 0;

}

int

TcpSocketImpl::Bind (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_endPoint = m_tcp->Allocate ();

  return FinishBind ();

}

int 

TcpSocketImpl::Bind (const Address &address)

{

  NS_LOG_FUNCTION (this<<address);

  if (!InetSocketAddress::IsMatchingType (address))

    {

      m_errno = ERROR_INVAL;

      return -1;

    }

  InetSocketAddress transport = InetSocketAddress::ConvertFrom (address);

  Ipv4Address ipv4 = transport.GetIpv4 ();

  uint16_t port = transport.GetPort ();

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

    {

      m_endPoint = m_tcp->Allocate ();

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

    }

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

    {

      m_endPoint = m_tcp->Allocate (port);

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

    }

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

    {

      m_endPoint = m_tcp->Allocate (ipv4);

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

    }

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

    {

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

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

    }

  return FinishBind ();

}

int 

TcpSocketImpl::ShutdownSend (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_shutdownSend = true;

  return 0;

}

int 

TcpSocketImpl::ShutdownRecv (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_shutdownRecv = false;

  return 0;

}

int

TcpSocketImpl::Close (void)

{

  NS_LOG_FUNCTION_NOARGS ();

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

    { // App close with pending data must wait until all data transmitted

      m_closeOnEmpty = true;

      NS_LOG_LOGIC("Socket " << this << 

                   " deferring close, state " << m_state);

      return 0;

    }

  Actions_t action  = ProcessEvent (APP_CLOSE);

  ProcessAction (action);

  ShutdownSend ();

  return 0;

}

int

TcpSocketImpl::Connect (const Address & address)

{

  NS_LOG_FUNCTION (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_remoteAddress = transport.GetIpv4 ();

  m_remotePort = transport.GetPort ();

  uint32_t localIfIndex;

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

  if (ipv4->GetIfIndexForDestination (m_remoteAddress, 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;

}

//p here is just data, no headers

int 

TcpSocketImpl::Send (Ptr<Packet> p, uint32_t flags) 

{

  NS_LOG_FUNCTION (this << p);

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

  {

    if (p->GetSize() > GetTxAvailable ())

    {

      m_errno = ERROR_MSGSIZE;

      return -1;

    }

    if (!m_pendingData)

    {

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

      m_firstPendingSequence = m_nextTxSequence; // Note seq of first

    }

    //PendingData::Add stores a copy of the Ptr p

    m_pendingData->Add (p);

    NS_LOG_DEBUG("TcpSock::Send, pdsize " << m_pendingData->Size() << 

        " state " << m_state);

    Actions_t action = ProcessEvent (APP_SEND);

    NS_LOG_DEBUG(" action " << action);

    if (!ProcessAction (action)) 

    {

      return -1; // Failed, return zero

    }

    return p->GetSize();

  }

  else

  {

    m_errno = ERROR_NOTCONN;

    return -1;

  }

}

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

{

  NS_LOG_FUNCTION (this << p << address);

  InetSocketAddress transport = InetSocketAddress::ConvertFrom (address);

  Ipv4Address ipv4 = transport.GetIpv4 ();

  uint16_t port = transport.GetPort ();

  return DoSendTo (p, ipv4, port);

}

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

{

  NS_LOG_FUNCTION (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 

TcpSocketImpl::SendTo (Ptr<Packet> p, uint32_t flags, const Address &address)

{

  NS_LOG_FUNCTION (this << address << p);

  if (!m_connected)

    {

      m_errno = ERROR_NOTCONN;

      return -1;

    }

  else

    {

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

    }

}

uint32_t

TcpSocketImpl::GetTxAvailable (void) const

{

  NS_LOG_FUNCTION_NOARGS ();

  if (m_pendingData != 0)

    {

      uint32_t unAckedDataSize = 

        m_pendingData->SizeFromSeq (m_firstPendingSequence, m_highestRxAck);

      NS_ASSERT (m_sndBufSize >= unAckedDataSize); //else a logical error

      return m_sndBufSize-unAckedDataSize;

    }

  else

    {

      return m_sndBufSize;

    }

}

int

TcpSocketImpl::Listen (void)

{

  NS_LOG_FUNCTION (this);

  // Linux quits EINVAL if we're not closed, so match what they do

  if (m_state != CLOSED)

    {

      m_errno = ERROR_INVAL;

      return -1;

    }

  Actions_t action = ProcessEvent (APP_LISTEN);

  ProcessAction (action);

  return 0;

}

Ptr<Packet>

TcpSocketImpl::Recv (uint32_t maxSize, uint32_t flags)

{

  NS_LOG_FUNCTION_NOARGS ();

  if(m_bufferedData.empty())

    {

      if(m_state == CLOSE_WAIT) //means EOF

        {

          return Create<Packet>();

        }

      //else, means nothing to read

      return 0;

    }

  UnAckData_t out; //serves as buffer to return up to the user

  UnAckData_t::iterator i;

  while (!m_bufferedData.empty ())

    { // Check the buffered data for delivery

      NS_LOG_LOGIC("TCP " << this << " bufferedData.size() " 

        << m_bufferedData.size () 

        << " time " << Simulator::Now ());

      i = m_bufferedData.begin ();

      SequenceNumber s1 = 0;

      if (i->first > m_nextRxSequence) 

        {

          break;  // we're done, no more in-sequence data exits

        }

      else // (i->first <= m_nextRxSequence)

        { // Two cases here.

          // 1) seq + length > nextRxSeq, can deliver partial

          // 2) seq + length <= nextRxSeq, deliver whole

          s1 = i->second->GetSize ();

          if (i->first + s1 > m_nextRxSequence)

            { // Remove partial data to prepare for delivery

              uint32_t avail = s1 + i->first - m_nextRxSequence;

              i->second = i->second->CreateFragment (0, avail);

            }

          // else this packet is okay to deliver whole

          // so don't do anything else and output it