/* -*- 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

//

// Normally, the use case for emulated net devices is in collections of

// small simulations that connect to the outside world through specific 

// interfaces.  For example, one could construct a number of virtual

// machines and connect them via a host-only network.  To use the emulated

// net device, you would need to set all of the host-only interfaces in

// promiscuous mode and provide an appropriate device name (search for "eth1"

// below).  One could also use the emulated net device in a testbed situation

// where the host on which the simulation is running has a specific interface

// of interested.  You would also need to set this specific interface into

// promiscuous mode and provide an appropriate device name.

//

// This philosophy carries over to this simple example.

//

// We don't assume any special configuration and all of the ns-3 emulated net

// devices will actually talk to the same underlying OS device.  We rely on 

// the fact that the OS will deliver copies of our packets to the other ns-3

// net devices since we operate in promiscuous mode.  

//

// Packets will be sent out over the device, but we use MAC spoofing.  The

// MAC addresses will be generated using the Organizationally Unique Identifier

// (OUI) 00:00:00 as a base.  This vendor code is not assigned to any 

// organization and so should not conflict with any real hardware.  We'll use 

// the first n of these addresses, where n is the number of nodes, in this

// simualtion.  It is up to you to determine that using these MAC addresses is

// okay on your network and won't conflict with anything else (including another

// simulation using emu devices) on your network.  Once you have made this 

// determination, you need to put the interface you chose into promiscuous mode.

// We don't do it for you since you need to think about it first.

//

// This simulation uses the real-time simulator and so will consume ten seconds

// of real time.

//

// By default, we create the following topology

//

//       n0    n1   n2   n3

//       |     |    |    |

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

//             "eth1"

//

// - UDP flows from n0 to n1 and back

// - DropTail queues 

// - Tracing of queues and packet receptions to file "udp-echo.tr"

// - pcap tracing on all devices

//

#include <fstream>

#include "ns3/core-module.h"

#include "ns3/simulator-module.h"

#include "ns3/helper-module.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("EmulatedUdpEchoExample");

int 

main (int argc, char *argv[])

{

  std::string deviceName ("eth1");

  uint32_t nNodes = 4;

  //

  // Allow the user to override any of the defaults at run-time, via command-line

  // arguments

  //

  CommandLine cmd;

  cmd.AddValue("deviceName", "device name", deviceName);

  cmd.AddValue("nNodes", "number of nodes to create (>= 2)", nNodes);

  cmd.Parse (argc, argv);

  GlobalValue::Bind ("SimulatorImplementationType", 

    StringValue ("ns3::RealtimeSimulatorImpl"));

  //

  // need at least two nodes

  //

  nNodes = nNodes < 2 ? 2 : nNodes;

  //

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

  //

  NS_LOG_INFO ("Create nodes.");

  NodeContainer n;

  n.Create (nNodes);

  InternetStackHelper internet;

  internet.Install (n);

  //

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

  //

  NS_LOG_INFO ("Create channels.");

  EmuHelper emu;

  emu.SetAttribute ("DeviceName", StringValue (deviceName));

  NetDeviceContainer d = emu.Install (n);

  //

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

  //

  Ipv4AddressHelper ipv4;

  NS_LOG_INFO ("Assign IP Addresses.");

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

  Ipv4InterfaceContainer i = ipv4.Assign (d);

  //

  // Create a UdpEchoServer application on node one.

  //

  NS_LOG_INFO ("Create Applications.");

  UdpEchoServerHelper server (9);

  ApplicationContainer apps = server.Install (n.Get(1));

  apps.Start (Seconds (1.0));

  apps.Stop (Seconds (10.0));

  //

  // Create a UdpEchoClient application to send UDP datagrams from node zero to node one.

  //

  uint32_t packetSize = 1024;

  uint32_t maxPacketCount = 1;

  Time interPacketInterval = Seconds (1.);

  UdpEchoClientHelper client (i.GetAddress (1), 9);

  client.SetAttribute ("MaxPackets", UintegerValue (maxPacketCount));

  client.SetAttribute ("Interval", TimeValue (interPacketInterval));

  client.SetAttribute ("PacketSize", UintegerValue (packetSize));

  apps = client.Install (n.Get (0));

  apps.Start (Seconds (2.0));

  apps.Stop (Seconds (10.0));

  std::ofstream ascii;

  ascii.open ("emu-udp-echo.tr");

  EmuHelper::EnablePcapAll ("emu-udp-echo");

  //

  // Now, do the actual simulation.

  //

  NS_LOG_INFO ("Run Simulation.");

  Simulator::Run ();

  Simulator::Destroy ();

  NS_LOG_INFO ("Done.");

}