/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2010 University of Washington
 *
 * 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 <iomanip>

#include "ns3/log.h"
#include "ns3/abort.h"
#include "ns3/test.h"
#include "ns3/pcap-file.h"
#include "ns3/config.h"
#include "ns3/string.h"
#include "ns3/uinteger.h"
#include "ns3/data-rate.h"
#include "ns3/inet-socket-address.h"
#include "ns3/point-to-point-helper.h"
#include "ns3/internet-stack-helper.h"
#include "ns3/ipv4-global-routing-helper.h"
#include "ns3/ipv4-address-helper.h"
#include "ns3/packet-sink-helper.h"
#include "ns3/tcp-socket-factory.h"
#include "ns3/node-container.h"
#include "ns3/simulator.h"
#include "ns3/error-model.h"
#include "ns3/pointer.h"
#include "ns3tcp-socket-writer.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("Ns3TcpLossTest");

const bool WRITE_VECTORS = false;           // set to true to write response vectors
const bool WRITE_LOGGING = false;            // set to true to write logging
const uint32_t PCAP_LINK_TYPE = 1187373557; // Some large random number -- we use to verify data was written by this program
const uint32_t PCAP_SNAPLEN   = 64;         // Don't bother to save much data

// ===========================================================================
// Tests of TCP implementation loss behavior
// ===========================================================================
//

class Ns3TcpLossTestCase : public TestCase
{
public:
  Ns3TcpLossTestCase ();
  Ns3TcpLossTestCase (std::string tcpModel, uint32_t testCase);
  virtual ~Ns3TcpLossTestCase () {}

private:
  virtual void DoSetup (void);
  virtual void DoRun (void);
  virtual void DoTeardown (void);

  Ptr<OutputStreamWrapper> m_osw;
  std::string m_pcapFilename;
  PcapFile m_pcapFile;
  uint32_t m_testCase;
  uint32_t m_totalTxBytes;
  uint32_t m_currentTxBytes;
  bool m_writeVectors;
  bool m_writeResults;
  bool m_writeLogging;
  bool m_needToClose;
  std::string m_tcpModel;

  void Ipv4L3Tx (std::string context, Ptr<const Packet> packet, Ptr<Ipv4> ipv4, uint32_t interface);
  void CwndTracer (uint32_t oldval, uint32_t newval);
  void WriteUntilBufferFull (Ptr<Socket> localSocket, uint32_t txSpace);
  void StartFlow (Ptr<Socket> localSocket, 
                  Ipv4Address servAddress, 
                  uint16_t servPort);

};

Ns3TcpLossTestCase::Ns3TcpLossTestCase ()
  : TestCase ("Check the operation of the TCP state machine for several cases"),
    m_testCase (0),
    m_totalTxBytes (200000),
    m_currentTxBytes (0),
    m_writeVectors (WRITE_VECTORS),
    m_writeResults (false),
    m_writeLogging (WRITE_LOGGING),
    m_needToClose (true),
    m_tcpModel ("ns3::TcpTahoe")
{
}

Ns3TcpLossTestCase::Ns3TcpLossTestCase (std::string tcpModel, uint32_t testCase)
  : TestCase ("Check the behaviour of TCP upon packet losses"),
    m_testCase (testCase),
    m_totalTxBytes (200000),
    m_currentTxBytes (0),
    m_writeVectors (WRITE_VECTORS),
    m_writeResults (false),
    m_writeLogging (WRITE_LOGGING),
    m_needToClose (true),
    m_tcpModel (tcpModel)
{
}

void
Ns3TcpLossTestCase::DoSetup (void)
{
    //
    // We expect there to be a file called ns3tcp-state-response-vectors.pcap in
    // response-vectors/ of this directory
    //
    std::ostringstream oss;
    oss << "/response-vectors/ns3tcp-loss-" << m_tcpModel << m_testCase << "-response-vectors.pcap";
    m_pcapFilename = NS_TEST_SOURCEDIR + oss.str ();

    if (m_writeVectors)
      {
        m_pcapFile.Open (m_pcapFilename, std::ios::out|std::ios::binary);
        m_pcapFile.Init(PCAP_LINK_TYPE, PCAP_SNAPLEN);
      }
    else
      {
        m_pcapFile.Open (m_pcapFilename, std::ios::in|std::ios::binary);
        NS_ABORT_MSG_UNLESS (m_pcapFile.GetDataLinkType () == PCAP_LINK_TYPE, "Wrong response vectors in directory");
      }
}

void
Ns3TcpLossTestCase::DoTeardown (void)
{
    m_pcapFile.Close ();
}

void
Ns3TcpLossTestCase::Ipv4L3Tx (std::string context, Ptr<const Packet> packet, Ptr<Ipv4> ipv4, uint32_t interface)
{
  //
  // We're not testing IP so remove and toss the header.  In order to do this,
  // though, we need to copy the packet since we have a const version.
  //
  Ptr<Packet> p = packet->Copy ();
  Ipv4Header ipHeader;
  p->RemoveHeader (ipHeader);

  //
  // What is left is the TCP header and any data that may be sent.  We aren't
  // sending any TCP data, so we expect what remains is only TCP header, which
  // is a small thing to save.
  //
  if (m_writeVectors)
    {
      //
      // Save the TCP under test response for later testing.
      //
      Time tNow = Simulator::Now ();
      int64_t tMicroSeconds = tNow.GetMicroSeconds ();
      
      uint32_t size = p->GetSize ();
      uint8_t *buf = new uint8_t[size];
      p->CopyData (buf, size);

      m_pcapFile.Write (uint32_t (tMicroSeconds / 1000000), 
                        uint32_t (tMicroSeconds % 1000000), 
                        buf, 
                        size);
      delete [] buf;
    }
  else
    {
      //
      // Read the TCP under test expected response from the expected vector
      // file and see if it still does the right thing.
      //
      uint8_t expected[PCAP_SNAPLEN];
      uint32_t tsSec, tsUsec, inclLen, origLen, readLen;
      m_pcapFile.Read (expected, sizeof(expected), tsSec, tsUsec, inclLen, origLen, readLen);

      uint8_t *actual = new uint8_t[readLen];
      p->CopyData (actual, readLen);

      uint32_t result = memcmp(actual, expected, readLen);

      delete [] actual;

      //
      // Avoid streams of errors -- only report the first.
      //
      if (GetErrorStatus () == false)
        {
          NS_TEST_EXPECT_MSG_EQ (result, 0, "Expected data comparison error");
        }
    }
}

void
Ns3TcpLossTestCase::CwndTracer (uint32_t oldval, uint32_t newval)
{
  if (m_writeLogging)
    {
      *(m_osw->GetStream ()) << "Moving cwnd from " << oldval << " to " << newval 
        << " at time " << Simulator::Now ().GetSeconds () 
        << " seconds" << std::endl;
    }
}

////////////////////////////////////////////////////////////////////
// Implementing an "application" to send bytes over a TCP connection
void 
Ns3TcpLossTestCase::WriteUntilBufferFull (Ptr<Socket> localSocket, uint32_t txSpace)
{
  while (m_currentTxBytes < m_totalTxBytes)
    {
      uint32_t left = m_totalTxBytes - m_currentTxBytes;
      uint32_t dataOffset = m_currentTxBytes % 1040;
      uint32_t toWrite = 1040 - dataOffset;
      uint32_t txAvail = localSocket->GetTxAvailable ();
      toWrite = std::min (toWrite, left);
      toWrite = std::min (toWrite, txAvail);
      if (txAvail == 0)
        {
          return;
        };
      if (m_writeLogging)
        {
          std::clog << "Submitting " << toWrite 
            << " bytes to TCP socket" << std::endl;
        }
      int amountSent = localSocket->Send (0, toWrite, 0);
      NS_ASSERT (amountSent > 0);  // Given GetTxAvailable() non-zero, amountSent should not be zero
      m_currentTxBytes += amountSent;
    }
  if (m_needToClose)
    {
      if (m_writeLogging)
        {
          std::clog << "Close socket at " 
            <<  Simulator::Now ().GetSeconds () << std::endl;
        }
      localSocket->Close ();
      m_needToClose = false;
    }
}

void 
Ns3TcpLossTestCase::StartFlow (Ptr<Socket> localSocket,
                                Ipv4Address servAddress,
                                uint16_t servPort)
{
  if (m_writeLogging)
    {
      std::clog << "Starting flow at time " 
        <<  Simulator::Now ().GetSeconds () << std::endl;
    }
  localSocket->Connect (InetSocketAddress (servAddress, servPort)); // connect

  // tell the tcp implementation to call WriteUntilBufferFull again
  // if we blocked and new tx buffer space becomes available
  localSocket->SetSendCallback (MakeCallback
                               (&Ns3TcpLossTestCase::WriteUntilBufferFull,
                                this));
  WriteUntilBufferFull (localSocket, localSocket->GetTxAvailable ());
}

void
Ns3TcpLossTestCase::DoRun (void)
{
  // Network topology
  //
  //           8Mb/s, 0.1ms       0.8Mb/s, 100ms
  //       s1-----------------r1-----------------k1
  //
  // Example corresponding to simulations in the paper "Simulation-based
  // Comparisons of Tahoe, Reno, and SACK TCP 

  std::ostringstream tcpModel;
  tcpModel << "ns3::Tcp" << m_tcpModel;
  Config::SetDefault ("ns3::TcpL4Protocol::SocketType", 
                      StringValue (tcpModel.str ()));
  Config::SetDefault ("ns3::TcpSocket::SegmentSize", UintegerValue (1000));
  Config::SetDefault ("ns3::TcpSocket::DelAckCount", UintegerValue (1));

  if (m_writeLogging)
    {
      LogComponentEnableAll (LOG_PREFIX_FUNC);
      LogComponentEnable ("TcpLossResponse", LOG_LEVEL_ALL);
      LogComponentEnable ("ErrorModel", LOG_LEVEL_DEBUG);
      LogComponentEnable ("TcpLossResponse", LOG_LEVEL_ALL);
      LogComponentEnable ("TcpNewReno", LOG_LEVEL_INFO);
      LogComponentEnable ("TcpReno", LOG_LEVEL_INFO);
      LogComponentEnable ("TcpTahoe", LOG_LEVEL_INFO);
      LogComponentEnable ("TcpSocketBase", LOG_LEVEL_INFO);
    }

  ////////////////////////////////////////////////////////
  // Topology construction
  //
  
  // Create three nodes: s1, r1, and k1
  NodeContainer s1r1;
  s1r1.Create (2);

  NodeContainer r1k1;
  r1k1.Add (s1r1.Get (1));
  r1k1.Create (1);

  // Set up TCP/IP stack to all nodes (and create loopback device at device 0)
  InternetStackHelper internet;
  internet.InstallAll ();

  // Connect the nodes
  PointToPointHelper p2p;
  p2p.SetDeviceAttribute ("DataRate", DataRateValue (DataRate (8000000)));
  p2p.SetChannelAttribute ("Delay", TimeValue (Seconds (0.0001)));
  NetDeviceContainer dev0 = p2p.Install (s1r1);
  p2p.SetDeviceAttribute ("DataRate", DataRateValue (DataRate (800000)));
  p2p.SetChannelAttribute ("Delay", TimeValue (Seconds (0.1)));
  NetDeviceContainer dev1 = p2p.Install (r1k1);

  // Add IP addresses to each network interfaces
  Ipv4AddressHelper ipv4;
  ipv4.SetBase ("10.1.3.0", "255.255.255.0");
  ipv4.Assign (dev0);
  ipv4.SetBase ("10.1.2.0", "255.255.255.0");
  Ipv4InterfaceContainer ipInterfs = ipv4.Assign (dev1);

  // Set up routes to all nodes
  Ipv4GlobalRoutingHelper::PopulateRoutingTables ();

  ////////////////////////////////////////////////////////
  // Send 20000 (totalTxBytes) bytes from node s1 to node k1
  //

  // Create a packet sink to receive packets on node k1
  uint16_t servPort = 50000; // Destination port number
  PacketSinkHelper sink ("ns3::TcpSocketFactory",
                         InetSocketAddress (Ipv4Address::GetAny (), servPort));
  ApplicationContainer apps = sink.Install (r1k1.Get (1));
  apps.Start (Seconds (0.0));
  apps.Stop (Seconds (100.0));

  // Create a data source to send packets on node s0.
  // Instead of full application, here use the socket directly by
  // registering callbacks in function StarFlow().
  Ptr<Socket> localSocket = Socket::CreateSocket (s1r1.Get (0), TcpSocketFactory::GetTypeId ());
  localSocket->Bind ();
  Simulator::ScheduleNow (&Ns3TcpLossTestCase::StartFlow, 
                          this, 
                          localSocket, 
                          ipInterfs.GetAddress (1), 
                          servPort);

  Config::Connect ("/NodeList/0/$ns3::Ipv4L3Protocol/Tx",
                   MakeCallback (&Ns3TcpLossTestCase::Ipv4L3Tx, this));

  Config::ConnectWithoutContext
    ("/NodeList/0/$ns3::TcpL4Protocol/SocketList/0/CongestionWindow",
     MakeCallback (&Ns3TcpLossTestCase::CwndTracer, this));

  ////////////////////////////////////////////////////////
  // Set up loss model at node k1
  //
  std::list<uint32_t> sampleList;
  switch (m_testCase)
    {
    case 0:
      break;
    case 1:
      // Force a loss for 15th data packet. TCP cwnd will be at 14 segments
      // (14000 bytes) when duplicate acknowledgments start to come.
      sampleList.push_back (16);
      break;
    case 2:
      sampleList.push_back (16);
      sampleList.push_back (17);
      break;
    case 3:
      sampleList.push_back (16);
      sampleList.push_back (17);
      sampleList.push_back (18);
      break;
    case 4:
      sampleList.push_back (16);
      sampleList.push_back (17);
      sampleList.push_back (18);
      sampleList.push_back (19);
      break;
    default:
      NS_FATAL_ERROR ("Program fatal error: loss value " << m_testCase << " not supported.");
      break;
    }

  Ptr<ReceiveListErrorModel> pem = CreateObject<ReceiveListErrorModel> ();
  pem->SetList (sampleList);
  dev1.Get (1)->SetAttribute ("ReceiveErrorModel", PointerValue (pem));

  // One can toggle the comment for the following line on or off to see the
  // effects of finite send buffer modelling.  One can also change the size of
  // that buffer.
  // localSocket->SetAttribute("SndBufSize", UintegerValue(4096));

  std::ostringstream oss;
  oss << "tcp-loss-" << m_tcpModel << m_testCase << "-test-case";
  if (m_writeResults)
    {
      p2p.EnablePcapAll (oss.str ());
      p2p.EnableAsciiAll (oss.str ());
    }

  std::ostringstream oss2;
  oss2 << "src/test/ns3tcp/Tcp" << m_tcpModel << "." << m_testCase << ".log";
  AsciiTraceHelper ascii;
  if (m_writeLogging)
    {
      m_osw = ascii.CreateFileStream (oss2.str ());
      *(m_osw->GetStream ()) << std::setprecision (9) << std::fixed;
      p2p.EnableAsciiAll (m_osw);
    }
  
  // Finally, set up the simulator to run.  The 1000 second hard limit is a
  // failsafe in case some change above causes the simulation to never end
  Simulator::Stop (Seconds (1000));
  Simulator::Run ();
  Simulator::Destroy ();
}

class Ns3TcpLossTestSuite : public TestSuite
{
public:
  Ns3TcpLossTestSuite ();
};

Ns3TcpLossTestSuite::Ns3TcpLossTestSuite ()
  : TestSuite ("ns3-tcp-loss", SYSTEM)
{
  Packet::EnablePrinting ();  // Enable packet metadata for all test cases
  AddTestCase (new Ns3TcpLossTestCase ("Tahoe", 0));
  AddTestCase (new Ns3TcpLossTestCase ("Tahoe", 1));
  AddTestCase (new Ns3TcpLossTestCase ("Tahoe", 2));
  AddTestCase (new Ns3TcpLossTestCase ("Tahoe", 3));
  AddTestCase (new Ns3TcpLossTestCase ("Tahoe", 4));

  AddTestCase (new Ns3TcpLossTestCase ("Reno", 0));
  AddTestCase (new Ns3TcpLossTestCase ("Reno", 1));
  AddTestCase (new Ns3TcpLossTestCase ("Reno", 2));
  AddTestCase (new Ns3TcpLossTestCase ("Reno", 3));
  AddTestCase (new Ns3TcpLossTestCase ("Reno", 4));

  AddTestCase (new Ns3TcpLossTestCase ("NewReno", 0));
  AddTestCase (new Ns3TcpLossTestCase ("NewReno", 1));
  AddTestCase (new Ns3TcpLossTestCase ("NewReno", 2));
  AddTestCase (new Ns3TcpLossTestCase ("NewReno", 3));
  AddTestCase (new Ns3TcpLossTestCase ("NewReno", 4));
}

static Ns3TcpLossTestSuite ns3TcpLossTestSuite;
