/* -*- 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

 */

// Network topology

//

//        n0     n1

//        |      | 

//       ----------

//       | Switch |

//       ----------

//        |      | 

//        n2     n3

//

//

// - CBR/UDP flows from n0 to n1 and from n3 to n0

// - DropTail queues 

// - Tracing of queues and packet receptions to file "csma-bridge.tr"

#include <iostream>

#include <fstream>

#include "ns3/core-module.h"

#include "ns3/network-module.h"

#include "ns3/applications-module.h"

#include "ns3/bridge-module.h"

#include "ns3/csma-module.h"

#include "ns3/internet-module.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("CsmaBridgeExample");

int 

main (int argc, char *argv[])

{

  //

  // Users may find it convenient to turn on explicit debugging

  // for selected modules; the below lines suggest how to do this

  //

#if 0 

  LogComponentEnable ("CsmaBridgeExample", LOG_LEVEL_INFO);

#endif

  //

  // Allow the user to override any of the defaults and the above Bind() at

  // run-time, via command-line arguments

  //

  CommandLine cmd;

  cmd.Parse (argc, argv);

  //

  // Explicitly create the nodes required by the topology (shown above).

  //

  NS_LOG_INFO ("Create nodes.");

  NodeContainer terminals;

  terminals.Create (4);

  NodeContainer csmaSwitch;

  csmaSwitch.Create (1);

  NS_LOG_INFO ("Build Topology");

  CsmaHelper csma;

  csma.SetChannelAttribute ("DataRate", DataRateValue (5000000));

  csma.SetChannelAttribute ("Delay", TimeValue (MilliSeconds (2)));

  // Create the csma links, from each terminal to the switch

  NetDeviceContainer terminalDevices;

  NetDeviceContainer switchDevices;

  for (int i = 0; i < 4; i++)

    {

      NetDeviceContainer link = csma.Install (NodeContainer (terminals.Get (i), csmaSwitch));

      terminalDevices.Add (link.Get (0));

      switchDevices.Add (link.Get (1));

    }

  // Create the bridge netdevice, which will do the packet switching

  Ptr<Node> switchNode = csmaSwitch.Get (0);

  BridgeHelper bridge;

  bridge.Install (switchNode, switchDevices);

  // Add internet stack to the terminals

  InternetStackHelper internet;

  internet.Install (terminals);

  // We've got the "hardware" in place.  Now we need to add IP addresses.

  //

  NS_LOG_INFO ("Assign IP Addresses.");

  Ipv4AddressHelper ipv4;

  ipv4.SetBase ("10.1.1.0", "255.255.255.0");

  ipv4.Assign (terminalDevices);

  //

  // Create an OnOff application to send UDP datagrams from node zero to node 1.

  //

  NS_LOG_INFO ("Create Applications.");

  uint16_t port = 9;   // Discard port (RFC 863)

  OnOffHelper onoff ("ns3::UdpSocketFactory", 

                     Address (InetSocketAddress (Ipv4Address ("10.1.1.2"), port)));

  ApplicationContainer app = onoff.Install (terminals.Get (0));

  // Start the application

  app.Start (Seconds (1.0));

  app.Stop (Seconds (10.0));

  // Create an optional packet sink to receive these packets

  PacketSinkHelper sink ("ns3::UdpSocketFactory",

                         Address (InetSocketAddress (Ipv4Address::GetAny (), port)));

  app = sink.Install (terminals.Get (1));

  app.Start (Seconds (0.0));

  // 

  // Create a similar flow from n3 to n0, starting at time 1.1 seconds

  //

  onoff.SetAttribute ("Remote", 

                      AddressValue (InetSocketAddress (Ipv4Address ("10.1.1.1"), port)));

  app = onoff.Install (terminals.Get (3));

  app.Start (Seconds (1.1));

  app.Stop (Seconds (10.0));

  app = sink.Install (terminals.Get (0));

  app.Start (Seconds (0.0));

  NS_LOG_INFO ("Configure Tracing.");

  //

  // Configure tracing of all enqueue, dequeue, and NetDevice receive events.

  // Trace output will be sent to the file "csma-bridge.tr"

  //

  AsciiTraceHelper ascii;

  csma.EnableAsciiAll (ascii.CreateFileStream ("csma-bridge.tr"));

  //

  // Also configure some tcpdump traces; each interface will be traced.

  // The output files will be named:

  //     csma-bridge-<nodeId>-<interfaceId>.pcap

  // and can be read by the "tcpdump -r" command (use "-tt" option to

  // display timestamps correctly)

  //

  csma.EnablePcapAll ("csma-bridge", false);

  //

  // Now, do the actual simulation.

  //

  NS_LOG_INFO ("Run Simulation.");

  Simulator::Run ();

  Simulator::Destroy ();

  NS_LOG_INFO ("Done.");

}