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

/*

 * 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

 *

 * based on tcp-socket-impl.cc, Author: Raj Bhattacharjea <raj.b@gatech.edu>

 * Author: Florian Westphal <fw@strlen.de>

 */

#include "ns3/node.h"

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

#include "ns3/log.h"

#include "ns3/ipv4.h"

#include "ipv4-end-point.h"

#include "nsc-tcp-l4-protocol.h"

#include "nsc-tcp-socket-impl.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>

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <netinet/ip.h>

#include <netinet/tcp.h>

#include "nsc/sim/sim_errno.h"

NS_LOG_COMPONENT_DEFINE ("NscTcpSocketImpl");

using namespace std;

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (NscTcpSocketImpl);

TypeId

NscTcpSocketImpl::GetTypeId ()

{

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

    .SetParent<TcpSocket> ()

    .AddTraceSource ("CongestionWindow",

                     "The TCP connection's congestion window",

                     MakeTraceSourceAccessor (&NscTcpSocketImpl::m_cWnd))

    ;

  return tid;

}

  NscTcpSocketImpl::NscTcpSocketImpl ()

  : m_endPoint (0),

    m_node (0),

    m_tcp (0),

    m_peerAddress ("0.0.0.0", 0),

    m_errno (ERROR_NOTERROR),

    m_shutdownSend (false),

    m_shutdownRecv (false),

    m_connected (false),

    m_state (CLOSED),

    m_closeOnEmpty (false),

    m_txBufferSize (0),

    m_rtt (0),

    m_lastMeasuredRtt (Seconds(0.0))

{

  NS_LOG_FUNCTION (this);

}

NscTcpSocketImpl::NscTcpSocketImpl(const NscTcpSocketImpl& sock)

  : TcpSocket(sock), //copy the base class callbacks

    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_peerAddress (sock.m_peerAddress),

    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_closeOnEmpty (sock.m_closeOnEmpty),

    m_segmentSize (sock.m_segmentSize),

    m_rxWindowSize (sock.m_rxWindowSize),

    m_advertisedWindowSize (sock.m_advertisedWindowSize),

    m_cWnd (sock.m_cWnd),

    m_ssThresh (sock.m_ssThresh),

    m_initialCWnd (sock.m_initialCWnd),

    m_rtt (0),

    m_lastMeasuredRtt (Seconds(0.0)),

    m_cnTimeout (sock.m_cnTimeout),

    m_cnCount (sock.m_cnCount),

    m_rxAvailable (0),

    m_nscTcpSocket (0),

    m_sndBufSize (sock.m_sndBufSize)

{

  NS_LOG_FUNCTION_NOARGS ();

  NS_LOG_LOGIC("Invoked the copy constructor");

  //copy the pending data if necessary

  if(!sock.m_txBuffer.empty () )

    {

      m_txBuffer = sock.m_txBuffer;

    }

  //copy the rtt if necessary

  if (sock.m_rtt)

    {

      m_rtt = sock.m_rtt->Copy();

    }

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

  //too; this is in SYN_ACK_TX

}

NscTcpSocketImpl::~NscTcpSocketImpl ()

{

  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;

}

void

NscTcpSocketImpl::SetNode (Ptr<Node> node)

{

  m_node = node;

  // Initialize some variables 

  m_cWnd = m_initialCWnd * m_segmentSize;

  m_rxWindowSize = m_advertisedWindowSize;

}

void 

NscTcpSocketImpl::SetTcp (Ptr<NscTcpL4Protocol> tcp)

{

  m_nscTcpSocket = tcp->m_nscStack->new_tcp_socket();

  m_tcp = tcp;

}

void 

NscTcpSocketImpl::SetRtt (Ptr<RttEstimator> rtt)

{

  m_rtt = rtt;

}

enum Socket::SocketErrno

NscTcpSocketImpl::GetErrno (void) const

{

  NS_LOG_FUNCTION_NOARGS ();

  return m_errno;

}

Ptr<Node>

NscTcpSocketImpl::GetNode (void) const

{

  NS_LOG_FUNCTION_NOARGS ();

  return m_node;

}

void 

NscTcpSocketImpl::Destroy (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_node = 0;

  m_endPoint = 0;

  m_tcp = 0;

}

int

NscTcpSocketImpl::FinishBind (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  if (m_endPoint == 0)

    {

      return -1;

    }

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

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

  m_localAddress = m_endPoint->GetLocalAddress ();

  m_localPort = m_endPoint->GetLocalPort ();

  return 0;

}

int

NscTcpSocketImpl::Bind (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_endPoint = m_tcp->Allocate ();

  return FinishBind ();

}

int 

NscTcpSocketImpl::Bind (const Address &address)

{

  NS_LOG_FUNCTION (this<<address);

  if (!InetSocketAddress::IsMatchingType (address))

    {

      return ERROR_INVAL;

    }

  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);

    }

  m_localPort = port;

  return FinishBind ();

}

int 

NscTcpSocketImpl::ShutdownSend (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_shutdownSend = true;

  return 0;

}

int 

NscTcpSocketImpl::ShutdownRecv (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  m_shutdownRecv = false;

  return 0;

}

int

NscTcpSocketImpl::Close (void)

{

  NS_LOG_FUNCTION (this << m_state);

  if (m_state == CLOSED)

    {

      return -1;

    }

  if (!m_txBuffer.empty ())

    { // 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;

    }

  m_nscTcpSocket->disconnect();

  m_state = CLOSED;

  ShutdownSend ();

  return 0;

}

int

NscTcpSocketImpl::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 ();

  struct in_addr remoteAddr;

  uint32_t addr32;

  m_remoteAddress.Serialize((uint8_t*)&addr32);

  remoteAddr.s_addr = addr32;

  m_nscTcpSocket->connect(inet_ntoa(remoteAddr), m_remotePort);

  m_state = SYN_SENT;

  return 0;

}

int

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

{

  NS_LOG_FUNCTION (this << p);

  NS_ASSERT (p->GetSize () > 0);

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

  {

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

    {

      m_errno = ERROR_MSGSIZE;

      return -1;

    }

    bool txEmpty = m_txBuffer.empty();

    if (m_state == ESTABLISHED)

      {

        if (txEmpty)

          {

            m_txBuffer.push(p);

            m_txBufferSize += p->GetSize ();

          }

        if (!SendPendingData())

          {

             if (m_errno == ERROR_AGAIN)

               {

                 return txEmpty ? p->GetSize () : -1;

               }

             if (txEmpty)

               {

                  m_txBuffer.pop ();

                  m_txBufferSize = 0;

               }

             return -1;

          }

      }

      else

      {  // SYN_SET -- Queue Data

         m_txBuffer.push(p);

         m_txBufferSize += p->GetSize ();

      }

    return p->GetSize ();

  }

  else

  {

    m_errno = ERROR_NOTCONN;

    return -1;

  }

}

int

NscTcpSocketImpl::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

NscTcpSocketImpl::GetTxAvailable (void) const

{

  NS_LOG_FUNCTION_NOARGS ();

  if (m_txBufferSize != 0)

    {

      NS_ASSERT (m_txBufferSize <= m_sndBufSize);

      return m_sndBufSize - m_txBufferSize;

    }

  else

    {

      return m_sndBufSize;

    }

}

int

NscTcpSocketImpl::Listen (uint32_t q)

{

  NS_LOG_FUNCTION (this << q);

  m_nscTcpSocket->listen(m_localPort);

  m_state = LISTEN;

  return 0;

}

void

NscTcpSocketImpl::NSCWakeup ()

{

  switch (m_state) {

  case SYN_SENT:

      if (!m_nscTcpSocket->is_connected())

          break;

      m_state = ESTABLISHED;

      Simulator::ScheduleNow(&NscTcpSocketImpl::ConnectionSucceeded, this);

      // fall through to schedule read/write events

  case ESTABLISHED:

      if (!m_txBuffer.empty ())

          Simulator::ScheduleNow(&NscTcpSocketImpl::SendPendingData, this);

      Simulator::ScheduleNow(&NscTcpSocketImpl::ReadPendingData, this);

      break;

  case LISTEN:

      Simulator::ScheduleNow(&NscTcpSocketImpl::Accept, this);

      break;

  case CLOSED: break;

  default:

      NS_LOG_DEBUG (this << " invalid state: " << m_state);

  }

}

Ptr<Packet>

NscTcpSocketImpl::Recv (uint32_t maxSize, uint32_t flags)

{

  NS_LOG_FUNCTION_NOARGS ();

  if (m_deliveryQueue.empty() )

    {

      return 0;

    }

  Ptr<Packet> p = m_deliveryQueue.front ();

  if (p->GetSize () <= maxSize)

    {

      m_deliveryQueue.pop ();

      m_rxAvailable -= p->GetSize ();

    }

  else

    {

      p = 0;

    }

  return p;

}

Ptr<Packet>

NscTcpSocketImpl::RecvFrom (uint32_t maxSize, uint32_t flags,

  Address &fromAddress)

{

  NS_LOG_FUNCTION (this << maxSize << flags);

  Ptr<Packet> packet = Recv (maxSize, flags);

  if (packet != 0)

    {

      SocketAddressTag tag;

      bool found;

      found = packet->FindFirstMatchingTag (tag);

      NS_ASSERT (found);

      fromAddress = tag.GetAddress ();

    }

  return packet;

}

uint32_t

NscTcpSocketImpl::GetRxAvailable (void) const

{

  NS_LOG_FUNCTION_NOARGS ();

  // We separately maintain this state to avoid walking the queue 

  // every time this might be called

  return m_rxAvailable;

}

void

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

{

  NSCWakeup();

}

void NscTcpSocketImpl::CompleteFork(void)

{

  // The address pairs (m_localAddress, m_localPort, m_remoteAddress, m_remotePort)

  // are bogus, but this isn't important at the moment, because

  // address <-> Socket handling is done by NSC internally.

  // We only need to add the new ns-3 socket to the list of sockets, so

  // we use plain Allocate() instead of Allocate(m_localAddress, ... )

  uint8_t buf[4];

  int port;

  size_t buflen = sizeof(buf);

  if (0 == m_nscTcpSocket->getpeername((void *) buf, &buflen, &port)) {

    m_remotePort = ntohs(port);

    m_remoteAddress = m_remoteAddress.Deserialize(buf);

    m_peerAddress = InetSocketAddress(m_remoteAddress, m_remotePort);

  }

  m_endPoint = m_tcp->Allocate ();

  //the cloned socket with be in listen state, so manually change state

  NS_ASSERT(m_state == LISTEN);

  m_state = ESTABLISHED;

  buflen = sizeof(buf);

  if (0 == m_nscTcpSocket->getsockname((void *) &buf, &buflen, &port))

    m_localAddress = m_localAddress.Deserialize(buf);

  NS_LOG_LOGIC ("NscTcpSocketImpl " << this << " accepted connection from " 

                 << m_remoteAddress << ":" << m_remotePort

                 << " to " << m_localAddress << ":" << m_localPort);

  //equivalent to FinishBind

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

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

  NotifyNewConnectionCreated (this, m_peerAddress);

}

void NscTcpSocketImpl::ConnectionSucceeded()

{ // We would preferred to have scheduled an event directly to

  // NotifyConnectionSucceeded, but (sigh) these are protected

  // and we can get the address of it :(