/* -*- 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

 *

 */

#include "ns3/core-module.h"

#include "ns3/simulator-module.h"

#include "ns3/node-module.h"

#include "ns3/helper-module.h"

#include "ns3/csma-module.h"

// Network topology (default)

//

//            n2     +          +     n3          .

//             | ... |\        /| ... |           .

//             ======= \      / =======           .

//              CSMA    \    /   CSMA             .

//                       \  /                     .

//            n1     +--- n0 ---+     n4          .

//             | ... |   /  \   | ... |           .

//             =======  /    \  =======           .

//              CSMA   /      \  CSMA             .

//                    /        \                  .

//            n6     +          +     n5          .

//             | ... |          | ... |           .

//             =======          =======           .

//              CSMA             CSMA             .

//

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("CsmaStar");

int 

main (int argc, char *argv[])

{

  //

  // Set up some default values for the simulation.

  //

  Config::SetDefault ("ns3::OnOffApplication::PacketSize", UintegerValue (137));

  // ??? try and stick 15kb/s into the data rate

  Config::SetDefault ("ns3::OnOffApplication::DataRate", StringValue ("14kb/s"));

  //

  // Default number of nodes in the star.  Overridable by command line argument.

  //

  uint32_t nNodes = 7;

  CommandLine cmd;

  cmd.AddValue("nNodes", "Number of nodes to place in the star", nNodes);

  cmd.Parse (argc, argv);

  NS_LOG_INFO ("Create nodes.");

  NodeContainer hubNode;

  NodeContainer spokeNodes;

  hubNode.Create (1);

  Ptr<Node> hub = hubNode.Get (0);

  spokeNodes.Create (nNodes - 1);

  CsmaHelper csma;

  csma.SetChannelAttribute ("DataRate", StringValue ("100Mbps"));

  csma.SetChannelAttribute ("Delay", StringValue ("1ms"));

  NS_LOG_INFO ("Build star topology.");

  NetDeviceContainer hubDevices, spokeDevices;

  csma.InstallStar (hubNode.Get (0), spokeNodes, hubDevices, spokeDevices);

  NodeContainer fillNodes;

  //

  // Just to be nasy, hang some more nodes off of the CSMA channel for each

  // spoke, so that there are a total of 16 nodes on each channel.  Stash

  // all of these new devices into a container.

  //

  NetDeviceContainer fillDevices;

  uint32_t nFill = 14;

  for (uint32_t i = 0; i < spokeDevices.GetN (); ++i)

    {

      Ptr<Channel> channel = spokeDevices.Get (i)->GetChannel ();

      Ptr<CsmaChannel> csmaChannel = channel->GetObject<CsmaChannel> ();

      NodeContainer newNodes;

      NetDeviceContainer newDevices;

      newNodes.Create (nFill);

      fillNodes.Add (newNodes);

      fillDevices.Add (csma.Install (newNodes, csmaChannel));

    }

  NS_LOG_INFO ("Install internet stack on all nodes.");

  InternetStackHelper internet;

  internet.Install (NodeContainer (hubNode, spokeNodes, fillNodes));

  NS_LOG_INFO ("Assign IP Addresses.");

  Ipv4AddressHelper address;

  //

  // Assign IPv4 interfaces and IP addresses to the devices we previously

  // created.  Keep track of the resulting addresses, one for the addresses

  // of the hub node, and one for addresses on the spoke nodes.  Despite the

  // name of the class (Ipv4InterfaceContainer), what is visible to clients 

  // is really the address not the interface.

  //

  Ipv4InterfaceContainer hubAddresses;

  Ipv4InterfaceContainer spokeAddresses;

  for(uint32_t i = 0; i < spokeNodes.GetN (); ++i)

  {

    std::ostringstream subnet;

    subnet << "10.1." << i << ".0";

    NS_LOG_INFO ("Assign IP Addresses for CSMA subnet " << subnet.str ());

    address.SetBase (subnet.str ().c_str (), "255.255.255.0");

    hubAddresses.Add (address.Assign (hubDevices.Get (i)));

    spokeAddresses.Add (address.Assign (spokeDevices.Get (i)));

    //

    // We assigned addresses to the logical hub and the first "drop" of the 

    // CSMA network that acts as the spoke, but we also have a number of fill

    // devices (nFill) also hanging off the CSMA network.  We have got to 

    // assign addresses to them as well.  We put all of the fill devices into

    // a single device container, so the first nFill devices are associated

    // with the channel connected to spokeDevices.Get (0), the second nFill

    // devices afe associated with the channel connected to spokeDevices.Get (1)

    // etc.

    //

    for (uint32_t j = 0; j < nFill; ++j)

      {

        address.Assign (fillDevices.Get (i * nFill + j));

      }

  }

  NS_LOG_INFO ("Create applications.");

  //

  // Create a packet sink on the star "hub" to receive packets.  

  // 

  uint16_t port = 50000;

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

  PacketSinkHelper packetSinkHelper ("ns3::TcpSocketFactory", hubLocalAddress);

  ApplicationContainer hubApp = packetSinkHelper.Install (hubNode);

  hubApp.Start (Seconds (1.0));

  hubApp.Stop (Seconds (10.0));

  //

  // Create OnOff applications to send TCP to the hub, one on each spoke node.

  //

  OnOffHelper onOffHelper ("ns3::TcpSocketFactory", Address ());

  onOffHelper.SetAttribute ("OnTime", RandomVariableValue (ConstantVariable (1)));

  onOffHelper.SetAttribute ("OffTime", RandomVariableValue (ConstantVariable (0)));

  ApplicationContainer spokeApps;

  for (uint32_t i = 0; i < spokeNodes.GetN (); ++i)

    {

      AddressValue remoteAddress (InetSocketAddress (hubAddresses.GetAddress (i), port));

      onOffHelper.SetAttribute ("Remote", remoteAddress);

      spokeApps.Add (onOffHelper.Install (spokeNodes.Get (i)));

    }

  spokeApps.Start (Seconds (1.0));

  spokeApps.Stop (Seconds (10.0));

  //

  // Because we are evil, we also add OnOff applications to send TCP to the hub 

  // from the fill devices on each CSMA link.  The first nFill nodes in the 

  // fillNodes container are on the CSMA network talking to the zeroth device

  // on the hub node.  The next nFill nodes are on the CSMA network talking to

  // the first device on the hub node, etc.  So the ith fillNode is associated

  // with the hub address found on the (i / nFill)th device on the hub node.

  //

  ApplicationContainer fillApps;

  for (uint32_t i = 0; i < fillNodes.GetN (); ++i)

    {

      AddressValue remoteAddress (InetSocketAddress (hubAddresses.GetAddress (i / nFill), port));

      onOffHelper.SetAttribute ("Remote", remoteAddress);

      fillApps.Add (onOffHelper.Install (fillNodes.Get (i)));

    }

  fillApps.Start (Seconds (1.0));

  fillApps.Stop (Seconds (10.0));

  NS_LOG_INFO ("Enable static global routing.");

  //

  // Turn on global static routing so we can actually be routed across the star.

  //

  NS_LOG_INFO ("Enable pcap tracing.");

  //

  // Do pcap tracing on all devices on all nodes.

  //

  CsmaHelper::EnablePcapAll ("csma-star", false);

  NS_LOG_INFO ("Run Simulation.");

  Simulator::Run ();

  Simulator::Destroy ();

  NS_LOG_INFO ("Done.");

  return 0;

}