/* -*- 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

 */

#include <fstream>

#include "ns3/core-module.h"

#include "ns3/helper-module.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("FifthScriptExample");

// ===========================================================================

//

//         node 0                 node 1

//   +----------------+    +----------------+

//   |    ns-3 TCP    |    |    ns-3 TCP    |

//   +----------------+    +----------------+

//   |    10.1.1.1    |    |    10.1.1.2    |

//   +----------------+    +----------------+

//   | point-to-point |    | point-to-point |

//   +----------------+    +----------------+

//           |                     |

//           +---------------------+

//                5 Mbps, 2 ms

//

//

// We want to look at changes in the ns-3 TCP congestion window.  We need

// to crank up a flow and hook the CongestionWindow attribute on the socket

// of the sender.  Normally one would use an on-off application to generate a

// flow, but this has a couple of problems.  First, the socket of the on-off 

// application is not created until Application Start time, so we wouldn't be 

// able to hook the socket (now) at configuration time.  Second, even if we 

// could arrange a call after start time, the socket is not public so we 

// couldn't get at it.

//

// So, we can cook up a simple version of the on-off application that does what

// we want.  On the plus side we don't need all of the complexity of the on-off

// application.  On the minus side, we don't have a helper, so we have to get

// a little more involved in the details, but this is trivial.

//

// So first, we create a socket and do the trace connect on it; then we pass 

// this socket into the constructor of our simple application which we then 

// install in the source node.

// ===========================================================================

//

class MyApp : public Application 

{

public:

  MyApp ();

  virtual ~MyApp();

  void Setup (Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate);

private:

  virtual void StartApplication (void);  

  virtual void StopApplication (void);

  void ScheduleTx (void);

  void SendPacket (void);

  Ptr<Socket>     m_socket;

  Address         m_peer;

  uint32_t        m_packetSize;

  uint32_t        m_nPackets;

  DataRate        m_dataRate;

  EventId         m_sendEvent;

  bool            m_running;

  uint32_t        m_packetsSent;

};

MyApp::MyApp ()

  : m_socket (0), 

    m_peer (), 

    m_packetSize (0), 

    m_nPackets (0), 

    m_dataRate (0), 

    m_sendEvent (), 

    m_running (false), 

    m_packetsSent (0)

{

}

MyApp::~MyApp()

{

  m_socket = 0;

}

void

MyApp::Setup (Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate)

{

  m_socket = socket;

  m_peer = address;

  m_packetSize = packetSize;

  m_nPackets = nPackets;

  m_dataRate = dataRate;

}

void

MyApp::StartApplication (void)

{

  m_running = true;

  m_packetsSent = 0;

  m_socket->Bind ();

  m_socket->Connect (m_peer);

  SendPacket ();

}

void 

MyApp::StopApplication (void)

{

  m_running = false;

  if (m_sendEvent.IsRunning ())

    {

      Simulator::Cancel (m_sendEvent);

    }

  if (m_socket)

    {

      m_socket->Close ();

    }

}

void 

MyApp::SendPacket (void)

{

  Ptr<Packet> packet = Create<Packet> (m_packetSize);

  m_socket->Send (packet);

  if (++m_packetsSent < m_nPackets)

    {

      ScheduleTx ();

    }

}

void 

MyApp::ScheduleTx (void)

{

  if (m_running)

    {

      Time tNext (Seconds (m_packetSize * 8 / static_cast<double> (m_dataRate.GetBitRate ())));

      m_sendEvent = Simulator::Schedule (tNext, &MyApp::SendPacket, this);

    }

}

static void

CwndChange (uint32_t oldCwnd, uint32_t newCwnd)

{

  NS_LOG_UNCOND (Simulator::Now ().GetSeconds () << "\t" << newCwnd);

}

static void

RxDrop (Ptr<const Packet> p)

{

  NS_LOG_UNCOND ("RxDrop at " << Simulator::Now ().GetSeconds ());

}

int 

main (int argc, char *argv[])

{

  NodeContainer nodes;

  nodes.Create (2);

  PointToPointHelper pointToPoint;

  pointToPoint.SetDeviceAttribute ("DataRate", StringValue ("5Mbps"));

  pointToPoint.SetChannelAttribute ("Delay", StringValue ("2ms"));

  NetDeviceContainer devices;

  devices = pointToPoint.Install (nodes);

  Ptr<RateErrorModel> em = CreateObjectWithAttributes<RateErrorModel> (

    "RanVar", RandomVariableValue (UniformVariable (0., 1.)),

    "ErrorRate", DoubleValue (0.00001));

  devices.Get (1)->SetAttribute ("ReceiveErrorModel", PointerValue (em));

  InternetStackHelper stack;

  stack.Install (nodes);

  Ipv4AddressHelper address;

  address.SetBase ("10.1.1.0", "255.255.255.252");

  Ipv4InterfaceContainer interfaces = address.Assign (devices);

  uint16_t sinkPort = 8080;

  Address sinkAddress (InetSocketAddress(interfaces.GetAddress (1), sinkPort));

  PacketSinkHelper packetSinkHelper ("ns3::TcpSocketFactory", InetSocketAddress (Ipv4Address::GetAny (), sinkPort));

  ApplicationContainer sinkApps = packetSinkHelper.Install (nodes.Get (1));

  sinkApps.Start (Seconds (0.));

  sinkApps.Stop (Seconds (20.));

  Ptr<Socket> ns3TcpSocket = Socket::CreateSocket (nodes.Get (0), TcpSocketFactory::GetTypeId ());

  ns3TcpSocket->TraceConnectWithoutContext ("CongestionWindow", MakeCallback (&CwndChange));

  Ptr<MyApp> app = CreateObject<MyApp> ();

  app->Setup (ns3TcpSocket, sinkAddress, 1040, 1000, DataRate ("1Mbps"));

  nodes.Get (0)->AddApplication (app);

  app->SetStartTime (Seconds (1.));

  app->SetStopTime (Seconds (20.));

  devices.Get (1)->TraceConnectWithoutContext("PhyRxDrop", MakeCallback (&RxDrop));

  Simulator::Stop (Seconds(20));

  Simulator::Run ();

  Simulator::Destroy ();

  return 0;

}