/* -*- 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

 *

 * Based on simple-global-routing.cc

 * ns-2 simple.tcl script (ported from ns-2)

 * Originally authored by Steve McCanne, 12/19/1996

 */

// Network topology

//

//  n0

//     \ 5 Mb/s, 2ms

//      \          1.5Mb/s, 10ms

//       n2 -------------------------n3

//      /

//     / 5 Mb/s, 2ms

//   n1

//

// - all links are point-to-point links with indicated one-way BW/delay

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

// - FTP/TCP flow from n0 to n3, starting at time 1.2 to time 1.35 sec.

// - UDP packet size of 210 bytes, with per-packet interval 0.00375 sec.

//   (i.e., DataRate of 448,000 bps)

// - DropTail queues 

// - Tracing of queues and packet receptions to file "virtual-net-device.tr"

// Tunneling changes (relative to the simple-global-routing example):

// n0 will receive an extra virtual interface with address 11.0.0.1

// n1 will also receive an extra virtual interface with the same address 11.0.0.1

// n3 will receive an extra virtual interface with address 11.0.0.254

// The flows will be between 11.0.0.x (tunnel) addresses instead of 10.1.x.y ones

// n3 will decide, on a per-packet basis, via random number, whether to

// send the packet to n0 or to n1.

//

// Note: here we create a tunnel where IP packets are tunneled over

// UDP/IP, but tunneling directly IP-over-IP would also be possible;

// see src/node/ipv4-raw-socket-factory.h.

#include <iostream>

#include <fstream>

#include <string>

#include <cassert>

#include "ns3/core-module.h"

#include "ns3/simulator-module.h"

#include "ns3/node-module.h"

#include "ns3/helper-module.h"

#include "ns3/global-route-manager.h"

#include "ns3/virtual-net-device.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("VirtualNetDeviceExample");

class Tunnel

{

  Ptr<Socket> m_n3Socket;

  Ptr<Socket> m_n0Socket;

  Ptr<Socket> m_n1Socket;

  Ipv4Address m_n3Address;

  Ipv4Address m_n0Address;

  Ipv4Address m_n1Address;

  UniformVariable m_rng;

  Ptr<VirtualNetDevice> m_n0Tap;

  Ptr<VirtualNetDevice> m_n1Tap;

  Ptr<VirtualNetDevice> m_n3Tap;

  bool

  N0N1VirtualSend (Ptr<Packet> packet, const Address& source, const Address& dest, uint16_t protocolNumber)

  {

    m_n3Socket->SendTo (packet, 0, InetSocketAddress (m_n3Address, 667));

    return true;

  }

  bool

  N3VirtualSend (Ptr<Packet> packet, const Address& source, const Address& dest, uint16_t protocolNumber)

  {

    if (m_rng.GetValue () < 0.25)

      {

        m_n0Socket->SendTo (packet, 0, InetSocketAddress (m_n0Address, 667));

      }

    else 

      {

        m_n1Socket->SendTo (packet, 0, InetSocketAddress (m_n1Address, 667));

      }

    return true;

  }

  void N3SocketRecv (Ptr<Socket> socket)

  {

    Ptr<Packet> packet = socket->Recv (65535, 0);

  }

  void N0SocketRecv (Ptr<Socket> socket)

  {

    Ptr<Packet> packet = socket->Recv (65535, 0);

  }

  void N1SocketRecv (Ptr<Socket> socket)

  {

    Ptr<Packet> packet = socket->Recv (65535, 0);

  }

public:

  Tunnel (Ptr<Node> n3, Ptr<Node> n0, Ptr<Node> n1,

          Ipv4Address n3Addr, Ipv4Address n0Addr, Ipv4Address n1Addr)

    : m_n3Address (n3Addr), m_n0Address (n0Addr), m_n1Address (n1Addr)

  {

    m_n3Socket = Socket::CreateSocket (n3, TypeId::LookupByName ("ns3::UdpSocketFactory"));

    m_n3Socket->Bind (InetSocketAddress (Ipv4Address::GetAny (), 667));

    m_n3Socket->SetRecvCallback (MakeCallback (&Tunnel::N3SocketRecv, this));    

    m_n0Socket = Socket::CreateSocket (n0, TypeId::LookupByName ("ns3::UdpSocketFactory"));

    m_n0Socket->Bind (InetSocketAddress (Ipv4Address::GetAny (), 667));

    m_n0Socket->SetRecvCallback (MakeCallback (&Tunnel::N0SocketRecv, this));    

    m_n1Socket = Socket::CreateSocket (n1, TypeId::LookupByName ("ns3::UdpSocketFactory"));

    m_n1Socket->Bind (InetSocketAddress (Ipv4Address::GetAny (), 667));

    m_n1Socket->SetRecvCallback (MakeCallback (&Tunnel::N1SocketRecv, this));

    // n0 tap device

    m_n0Tap = CreateObject<VirtualNetDevice> ();

    n0->AddDevice (m_n0Tap);

    Ptr<Ipv4> ipv4 = n0->GetObject<Ipv4> ();

    uint32_t i = ipv4->AddInterface (m_n0Tap);

    ipv4->AddAddress (i, Ipv4InterfaceAddress (Ipv4Address ("11.0.0.1"), Ipv4Mask ("255.255.255.0")));

    ipv4->SetUp (i);

    // n1 tap device

    m_n1Tap = CreateObject<VirtualNetDevice> ();

    n1->AddDevice (m_n1Tap);

    ipv4 = n1->GetObject<Ipv4> ();

    i = ipv4->AddInterface (m_n1Tap);

    ipv4->AddAddress (i, Ipv4InterfaceAddress (Ipv4Address ("11.0.0.1"), Ipv4Mask ("255.255.255.0")));

    ipv4->SetUp (i);

    // n3 tap device

    m_n3Tap = CreateObject<VirtualNetDevice> ();

    n3->AddDevice (m_n3Tap);

    ipv4 = n3->GetObject<Ipv4> ();

    i = ipv4->AddInterface (m_n3Tap);

    ipv4->AddAddress (i, Ipv4InterfaceAddress (Ipv4Address ("11.0.0.254"), Ipv4Mask ("255.255.255.0")));

    ipv4->SetUp (i);

  }

};

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 ("VirtualNetDeviceExample", LOG_LEVEL_INFO);

#endif

  // Set up some default values for the simulation.  Use the 

  Config::SetDefault ("ns3::OnOffApplication::PacketSize", UintegerValue (210));

  Config::SetDefault ("ns3::OnOffApplication::DataRate", StringValue ("448kb/s"));

  //DefaultValue::Bind ("DropTailQueue::m_maxPackets", 30);   

  // Allow the user to override any of the defaults and the above

  // DefaultValue::Bind ()s at run-time, via command-line arguments

  CommandLine cmd;

  cmd.Parse (argc, argv);

  // Here, we will explicitly create four nodes.  In more sophisticated

  // topologies, we could configure a node factory.

  NS_LOG_INFO ("Create nodes.");

  NodeContainer c;

  c.Create (4);

  NodeContainer n0n2 = NodeContainer (c.Get(0), c.Get (2));

  NodeContainer n1n2 = NodeContainer (c.Get(1), c.Get (2));

  NodeContainer n3n2 = NodeContainer (c.Get(3), c.Get (2));

  InternetStackHelper internet;

  internet.Install (c);

  // We create the channels first without any IP addressing information

  NS_LOG_INFO ("Create channels.");

  PointToPointHelper p2p;

  p2p.SetDeviceAttribute ("DataRate", StringValue ("5Mbps"));

  p2p.SetChannelAttribute ("Delay", StringValue ("2ms"));

  NetDeviceContainer d0d2 = p2p.Install (n0n2);

  NetDeviceContainer d1d2 = p2p.Install (n1n2);

  p2p.SetDeviceAttribute ("DataRate", StringValue ("1500kbps"));

  p2p.SetChannelAttribute ("Delay", StringValue ("10ms"));

  NetDeviceContainer d3d2 = p2p.Install (n3n2);

  // Later, we add IP addresses.  

  NS_LOG_INFO ("Assign IP Addresses.");

  Ipv4AddressHelper ipv4;

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

  Ipv4InterfaceContainer i0i2 = ipv4.Assign (d0d2);

  ipv4.SetBase ("10.1.2.0", "255.255.255.0");

  Ipv4InterfaceContainer i1i2 = ipv4.Assign (d1d2);

  ipv4.SetBase ("10.1.3.0", "255.255.255.0");

  Ipv4InterfaceContainer i3i2 = ipv4.Assign (d3d2);

  // Create router nodes, initialize routing database and set up the routing

  // tables in the nodes.

  GlobalRouteManager::PopulateRoutingTables ();

  // Add the tunnels

  Tunnel tunnel (c.Get (3), c.Get (0), c.Get (1),

                 i3i2.GetAddress (0), i0i2.GetAddress (0), i1i2.GetAddress (0));

  // Create the OnOff application to send UDP datagrams of size

  // 210 bytes at a rate of 448 Kb/s

  NS_LOG_INFO ("Create Applications.");

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

  OnOffHelper onoff ("ns3::UdpSocketFactory", 

                     Address (InetSocketAddress (Ipv4Address ("11.0.0.254"), port)));

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

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

  ApplicationContainer apps = onoff.Install (c.Get (0));

  apps.Start (Seconds (1.0));

  apps.Stop (Seconds (10.0));

  // Create a packet sink to receive these packets

  PacketSinkHelper sink ("ns3::UdpSocketFactory",

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

  apps = sink.Install (c.Get (3));

  apps.Start (Seconds (1.0));

  apps.Stop (Seconds (10.0));

  // Create a similar flow from n3 to n1, starting at time 1.1 seconds

  onoff.SetAttribute ("Remote", 

                      AddressValue (InetSocketAddress (Ipv4Address ("11.0.0.2"), port)));

  apps = onoff.Install (c.Get (3));

  apps.Start (Seconds (1.1));

  apps.Stop (Seconds (10.0));

  // Create a packet sink to receive these packets

  apps = sink.Install (c.Get (1));

  apps.Start (Seconds (1.1));

  apps.Stop (Seconds (10.0));

  std::ofstream ascii;

  ascii.open ("virtual-net-device.tr");

  PointToPointHelper::EnablePcapAll ("virtual-net-device");

  PointToPointHelper::EnableAsciiAll (ascii);

  NS_LOG_INFO ("Run Simulation.");

  Simulator::Run ();

  Simulator::Destroy ();

  NS_LOG_INFO ("Done.");

  return 0;

}