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

/*

 * Copyright (c) 2010 IITP RAS

 *

 * 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

 *

 * Authors: Pavel Boyko <boyko@iitp.ru>

 */

/*

 * Classical hidden terminal problem and its RTS/CTS solution.

 *

 * Topology: [node 0] <-- -50 dB --> [node 1] <-- -50 dB --> [node 2]

 * 

 * This example illustrates the use of 

 *  - Wifi in ad-hoc mode

 *  - Matrix propagation loss model

 *  - Use of OnOffApplication to generate CBR stream 

 *  - IP flow monitor

 */

#include "ns3/core-module.h"

#include "ns3/propagation-module.h"

#include "ns3/network-module.h"

#include "ns3/applications-module.h"

#include "ns3/mobility-module.h"

#include "ns3/internet-module.h"

#include "ns3/flow-monitor-module.h"

#include "ns3/wifi-module.h"

using namespace ns3;

/// Run single 10 seconds experiment with enabled or disabled RTS/CTS mechanism

void experiment (bool enableCtsRts)

{

  // 0. Enable or disable CTS/RTS

  UintegerValue ctsThr = (enableCtsRts ? UintegerValue (100) : UintegerValue (2200));

  Config::SetDefault ("ns3::WifiRemoteStationManager::RtsCtsThreshold", ctsThr);

  // 1. Create 3 nodes 

  NodeContainer nodes;

  nodes.Create (3);

  // 2. Place nodes somehow, this is required by every wireless simulation

  for (size_t i = 0; i < 3; ++i)

    {

      nodes.Get (i)->AggregateObject (CreateObject<ConstantPositionMobilityModel> ());

    }

  // 3. Create propagation loss matrix

  Ptr<MatrixPropagationLossModel> lossModel = CreateObject<MatrixPropagationLossModel> ();

  lossModel->SetDefaultLoss (200); // set default loss to 200 dB (no link)

  lossModel->SetLoss (nodes.Get (0)->GetObject<MobilityModel>(), nodes.Get (1)->GetObject<MobilityModel>(), 50); // set symmetric loss 0 <-> 1 to 50 dB

  lossModel->SetLoss (nodes.Get (2)->GetObject<MobilityModel>(), nodes.Get (1)->GetObject<MobilityModel>(), 50); // set symmetric loss 2 <-> 1 to 50 dB

  // 4. Create & setup wifi channel

  Ptr<YansWifiChannel> wifiChannel = CreateObject <YansWifiChannel> ();

  wifiChannel->SetPropagationLossModel (lossModel);

  wifiChannel->SetPropagationDelayModel (CreateObject <ConstantSpeedPropagationDelayModel> ());

  // 5. Install wireless devices

  WifiHelper wifi;

  wifi.SetStandard (WIFI_PHY_STANDARD_80211b);

  wifi.SetRemoteStationManager ("ns3::ConstantRateWifiManager", 

                                "DataMode",StringValue ("DsssRate2Mbps"), 

                                "ControlMode",StringValue ("DsssRate1Mbps"));

  YansWifiPhyHelper wifiPhy =  YansWifiPhyHelper::Default ();

  wifiPhy.SetChannel (wifiChannel);

  NqosWifiMacHelper wifiMac = NqosWifiMacHelper::Default ();

  wifiMac.SetType ("ns3::AdhocWifiMac"); // use ad-hoc MAC

  NetDeviceContainer devices = wifi.Install (wifiPhy, wifiMac, nodes);

  // uncomment the following to have athstats output

  // AthstatsHelper athstats;

  // athstats.EnableAthstats(enableCtsRts ? "basic-athstats-node" : "rtscts-athstats-node", nodes);

  // uncomment the following to have pcap output

  //wifiPhy.EnablePcap (enableCtsRts ? "basic-pcap-node" : "rtscts-pcap-node", nodes);

  // 6. Install TCP/IP stack & assign IP addresses

  InternetStackHelper internet;

  internet.Install (nodes);

  Ipv4AddressHelper ipv4;

  ipv4.SetBase ("10.0.0.0", "255.0.0.0");

  ipv4.Assign (devices);

  // 7. Install applications: two CBR streams each saturating the channel 

  ApplicationContainer cbrApps;

  uint16_t cbrPort = 12345;

  OnOffHelper onOffHelper ("ns3::UdpSocketFactory", InetSocketAddress (Ipv4Address ("10.0.0.2"), cbrPort));

  onOffHelper.SetAttribute ("PacketSize", UintegerValue (200));

  onOffHelper.SetAttribute ("OnTime",  StringValue ("ns3::ConstantRandomVariable[Constant=1]"));

  onOffHelper.SetAttribute ("OffTime", StringValue ("ns3::ConstantRandomVariable[Constant=0]"));

  // flow 1:  node 0 -> node 1

  onOffHelper.SetAttribute ("DataRate", StringValue ("3000000bps"));

  onOffHelper.SetAttribute ("StartTime", TimeValue (Seconds (1.000000)));

  cbrApps.Add (onOffHelper.Install (nodes.Get (0))); 

  // flow 2:  node 2 -> node 1

  // The slightly different start times and data rates are a workround

  // for Bug 388 and Bug 912

  // http://www.nsnam.org/bugzilla/show_bug.cgi?id=912

  // http://www.nsnam.org/bugzilla/show_bug.cgi?id=388

  onOffHelper.SetAttribute ("DataRate", StringValue ("3001100bps"));

  onOffHelper.SetAttribute ("StartTime", TimeValue (Seconds (1.001)));

  cbrApps.Add (onOffHelper.Install (nodes.Get (2))); 

  // we also use separate UDP applications that will send a single

  // packet before the CBR flows start. 

  // This is a workround for the lack of perfect ARP, see Bug 187

  // http://www.nsnam.org/bugzilla/show_bug.cgi?id=187

  uint16_t  echoPort = 9;

  UdpEchoClientHelper echoClientHelper (Ipv4Address ("10.0.0.2"), echoPort);

  echoClientHelper.SetAttribute ("MaxPackets", UintegerValue (1));

  echoClientHelper.SetAttribute ("Interval", TimeValue (Seconds (0.1)));

  echoClientHelper.SetAttribute ("PacketSize", UintegerValue (10));

  ApplicationContainer pingApps;

  // again using different start times to workaround Bug 388 and Bug 912

  echoClientHelper.SetAttribute ("StartTime", TimeValue (Seconds (0.001)));

  pingApps.Add (echoClientHelper.Install (nodes.Get (0))); 

  echoClientHelper.SetAttribute ("StartTime", TimeValue (Seconds (0.006)));

  pingApps.Add (echoClientHelper.Install (nodes.Get (2)));

  // 8. Install FlowMonitor on all nodes

  FlowMonitorHelper flowmon;

  Ptr<FlowMonitor> monitor = flowmon.InstallAll ();

  // 9. Run simulation for 10 seconds

  Simulator::Stop (Seconds (10));

  Simulator::Run ();

  // 10. Print per flow statistics

  monitor->CheckForLostPackets ();

  Ptr<Ipv4FlowClassifier> classifier = DynamicCast<Ipv4FlowClassifier> (flowmon.GetClassifier ());

  std::map<FlowId, FlowMonitor::FlowStats> stats = monitor->GetFlowStats ();

  for (std::map<FlowId, FlowMonitor::FlowStats>::const_iterator i = stats.begin (); i != stats.end (); ++i)

    {

      // first 2 FlowIds are for ECHO apps, we don't want to display them

      if (i->first > 2)

        {

          Ipv4FlowClassifier::FiveTuple t = classifier->FindFlow (i->first);

          std::cout << "  Rx Bytes:   " << i->second.rxBytes << "\n";

        }

    }

  // 11. Cleanup

  Simulator::Destroy ();

}

int main (int argc, char **argv)

{

  std::cout << "Hidden station experiment with RTS/CTS disabled:\n" << std::flush;

  experiment (false);

  std::cout << "------------------------------------------------\n";

  std::cout << "Hidden station experiment with RTS/CTS enabled:\n";

  experiment (true);

  return 0;

}