/* -*- 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 <string>

#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 ("Ns3TcpStateTest");

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 = 1187373554; // 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 Ns3TcpStateTestCase : public TestCase
{
public:
  Ns3TcpStateTestCase ();
  Ns3TcpStateTestCase (uint32_t testCase);
  virtual ~Ns3TcpStateTestCase () {}

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

  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;

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

};

Ns3TcpStateTestCase::Ns3TcpStateTestCase ()
  : TestCase ("Check the operation of the TCP state machine for several cases"),
    m_testCase (0),
    m_totalTxBytes (20000),
    m_currentTxBytes (0),
    m_writeVectors (WRITE_VECTORS),
    m_writeResults (false),
    m_writeLogging (WRITE_LOGGING),
    m_needToClose (true)
{
}

Ns3TcpStateTestCase::Ns3TcpStateTestCase (uint32_t testCase)
  : TestCase ("Check the operation of the TCP state machine for several cases"),
    m_testCase (testCase),
    m_totalTxBytes (20000),
    m_currentTxBytes (0),
    m_writeVectors (WRITE_VECTORS),
    m_writeResults (false),
    m_writeLogging (WRITE_LOGGING),
    m_needToClose (true)
{
}

void
Ns3TcpStateTestCase::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-state" << m_testCase << "-response-vectors.pcap";
  m_pcapFilename = static_cast<std::string> (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
Ns3TcpStateTestCase::DoTeardown (void)
{
  m_pcapFile.Close ();
}

void
Ns3TcpStateTestCase::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 (IsStatusSuccess ())
        {
          NS_TEST_EXPECT_MSG_EQ (result, 0, "Expected data comparison error");
        }
    }
}

////////////////////////////////////////////////////////////////////
// Implementing an "application" to send bytes over a TCP connection
void 
Ns3TcpStateTestCase::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 
Ns3TcpStateTestCase::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
                                  (&Ns3TcpStateTestCase::WriteUntilBufferFull,
                                  this));
  WriteUntilBufferFull (localSocket, localSocket->GetTxAvailable ());
}

void
Ns3TcpStateTestCase::DoRun (void)
{
  // Network topology
  //
  //           10Mb/s, 0.1ms      10Mb/s, 0.1ms
  //       n0-----------------n1-----------------n2

  std::string tcpModel ("ns3::TcpNewReno");

  Config::SetDefault ("ns3::TcpL4Protocol::SocketType", StringValue (tcpModel));
  Config::SetDefault ("ns3::TcpSocket::SegmentSize", UintegerValue (1000));
  Config::SetDefault ("ns3::TcpSocket::DelAckCount", UintegerValue (1));
  Config::SetDefault ("ns3::DropTailQueue::MaxPackets", UintegerValue (20));

  if (m_writeLogging)
    {
      LogComponentEnableAll (LOG_PREFIX_FUNC);
      LogComponentEnable ("TcpTestCases", LOG_LEVEL_ALL);
      LogComponentEnable ("ErrorModel", LOG_LEVEL_DEBUG);
      LogComponentEnable ("TcpTestCases", 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
  NodeContainer n0n1;
  n0n1.Create (2);

  NodeContainer n1n2;
  n1n2.Add (n0n1.Get (1));
  n1n2.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 (1000000)));
  p2p.SetChannelAttribute ("Delay", TimeValue (Seconds (0.0001)));
  NetDeviceContainer dev0 = p2p.Install (n0n1);
  NetDeviceContainer dev1 = p2p.Install (n1n2);

  // 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 ();

  ////////////////////////////////////////////////////////
  // A flow from node n0 to node n2
  //

  // Create a packet sink to receive packets on node n2
  uint16_t servPort = 50000; // Destination port number
  PacketSinkHelper sink ("ns3::TcpSocketFactory", InetSocketAddress (Ipv4Address::GetAny (), servPort));
  ApplicationContainer sinkApps = sink.Install (n1n2.Get (1));
  sinkApps.Start (Seconds (0.0));
  sinkApps.Stop (Seconds (100.0));

  // Create a data source to send packets on node n0
  // Instead of full application, here use the socket directly by
  // registering callbacks in function StarFlow().
  Ptr<Socket> localSocket = Socket::CreateSocket (n0n1.Get (0),
                                                  TcpSocketFactory::GetTypeId ());
  localSocket->Bind ();
  Simulator::ScheduleNow (&Ns3TcpStateTestCase::StartFlow, this, 
                          localSocket, ipInterfs.GetAddress (1), servPort);

  Config::Connect ("/NodeList/0/$ns3::Ipv4L3Protocol/Tx",
                   MakeCallback (&Ns3TcpStateTestCase::Ipv4L3Tx, this));

  ////////////////////////////////////////////////////////
  // Set up different test cases: Lost model at node n1, different file size
  //

  std::list<uint32_t> dropListN0;
  std::list<uint32_t> dropListN1;
  std::string caseDescription;
  switch (m_testCase)
    {
    case 0:
      m_totalTxBytes = 1000;
      caseDescription = "Verify connection establishment";
      break;
    case 1:
      m_totalTxBytes = 100*1000;
      caseDescription = "Verify a bigger (100 pkts) transfer: Sliding window operation, etc.";
      break;
    case 2:
      m_totalTxBytes = 1000;
      caseDescription = "Survive a SYN lost";
      dropListN0.push_back (0);
      break;
    case 3:
      m_totalTxBytes = 2000;
      caseDescription = "Survive a SYN+ACK lost";
      dropListN1.push_back (0);
      break;
    case 4:
      m_totalTxBytes = 2000;
      caseDescription = "Survive a ACK (last packet in 3-way handshake) lost";
      dropListN0.push_back (1);
      break;
    case 5:
      m_totalTxBytes = 0;
      caseDescription = "Immediate FIN upon SYN_RCVD";
      m_needToClose = false;
      dropListN0.push_back (1); // Hide the ACK in 3WHS
      Simulator::Schedule (Seconds (0.002), &Socket::Close, localSocket);
      break;
    case 6:
      m_totalTxBytes = 5000;
      caseDescription = "Simulated simultaneous close";
      dropListN1.push_back (5); // Hide the ACK-to-FIN from n2
      break;
    case 7:
      m_totalTxBytes = 5000;
      caseDescription = "FIN check 1: Loss of initiator's FIN. Wait until app close";
      m_needToClose = false;
      dropListN0.push_back (7); // Hide the FIN from n0
      Simulator::Schedule (Seconds (0.04), &Socket::Close, localSocket);
      break;
    case 8:
      m_totalTxBytes = 5000;
      caseDescription = "FIN check 2: Loss responder's FIN. FIN will be resent after last ack timeout";
      dropListN1.push_back (6); // Hide the FIN from n2
      break;
    default:
      NS_FATAL_ERROR ("Program fatal error: specified test case not supported: "
                      << m_testCase);
      break;
    }

  Ptr<ReceiveListErrorModel> errN0 = CreateObject<ReceiveListErrorModel> ();
  errN0->SetList (dropListN0);
  dev0.Get (1)->SetAttribute ("ReceiveErrorModel", PointerValue (errN0));

  Ptr<ReceiveListErrorModel> errN1 = CreateObject<ReceiveListErrorModel> ();
  errN1->SetList (dropListN1);
  dev1.Get (0)->SetAttribute ("ReceiveErrorModel", PointerValue (errN1));

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

  if (m_writeLogging)
    {
      Ptr<OutputStreamWrapper> osw = Create<OutputStreamWrapper> (&std::clog);
      *(osw->GetStream ()) << std::setprecision (9) << std::fixed;
      p2p.EnableAsciiAll (osw);

      std::clog << std::endl << "Running TCP test-case " << m_testCase << ": "
                << caseDescription << std::endl;
    }

  // 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 Ns3TcpStateTestSuite : public TestSuite
{
public:
  Ns3TcpStateTestSuite ();
};

Ns3TcpStateTestSuite::Ns3TcpStateTestSuite ()
  : TestSuite ("ns3-tcp-state", SYSTEM)
{
  Packet::EnablePrinting ();  // Enable packet metadata for all test cases
  AddTestCase (new Ns3TcpStateTestCase (0), TestCase::QUICK);
  AddTestCase (new Ns3TcpStateTestCase (1), TestCase::QUICK);
  AddTestCase (new Ns3TcpStateTestCase (2), TestCase::QUICK);
  AddTestCase (new Ns3TcpStateTestCase (3), TestCase::QUICK);
  AddTestCase (new Ns3TcpStateTestCase (4), TestCase::QUICK);
  AddTestCase (new Ns3TcpStateTestCase (5), TestCase::QUICK);
  AddTestCase (new Ns3TcpStateTestCase (6), TestCase::QUICK);
  AddTestCase (new Ns3TcpStateTestCase (7), TestCase::QUICK);
  AddTestCase (new Ns3TcpStateTestCase (8), TestCase::QUICK);
}

static Ns3TcpStateTestSuite ns3TcpLossTestSuite;
