/* -*- 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

 *

 */

// This script illustrates the behavior of equal-cost multipath routing 

// (ECMP) with Ipv4 global routing, across three equal-cost paths

//

// Network topology:

//

//           n2

//          /  \ all links 

//         /    \  point-to-point

//  n0---n1--n3--n5----n6

//         \    /

//          \  /

//           n4

//

// - multiple UDP flows from n0 to n6

// - Tracing of queues and packet receptions to file "ecmp-global-routing.tr"

// - pcap traces on nodes n2, n3, and n4

#include <iostream>

#include <fstream>

#include <string>

#include <cassert>

#include "ns3/core-module.h"

#include "ns3/network-module.h"

#include "ns3/applications-module.h"

#include "ns3/point-to-point-module.h"

#include "ns3/internet-module.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("EcmpGlobalRoutingExample");

int 

main (int argc, char *argv[])

{

  uint32_t ecmpMode = 1;

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

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

  CommandLine cmd;

  cmd.AddValue ("EcmpMode", "Ecmp Mode: (0 none, 1 random, 2 flow)", ecmpMode);

  cmd.Parse (argc, argv);

  switch (ecmpMode)

    {

      case 0:

        break;  //no ECMP

      case 1:

        Config::SetDefault ("ns3::Ipv4GlobalRouting::RandomEcmpRouting", BooleanValue (true));

        break;

      case 2:

        Config::SetDefault ("ns3::Ipv4GlobalRouting::FlowEcmpRouting", BooleanValue (true));

        break;  

      default:

        NS_FATAL_ERROR ("Illegal command value for EcmpMode: " << ecmpMode);

        break;

    }

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

  NS_LOG_INFO ("Create nodes.");

  NodeContainer c;

  c.Create (7);

  NodeContainer n0n1 = NodeContainer (c.Get (0), c.Get (1));

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

  NodeContainer n1n3 = NodeContainer (c.Get (1), c.Get (3));

  NodeContainer n1n4 = NodeContainer (c.Get (1), c.Get (4));

  NodeContainer n2n5 = NodeContainer (c.Get (2), c.Get (5));

  NodeContainer n3n5 = NodeContainer (c.Get (3), c.Get (5));

  NodeContainer n4n5 = NodeContainer (c.Get (4), c.Get (5));

  NodeContainer n5n6 = NodeContainer (c.Get (5), c.Get (6));

  InternetStackHelper internet;

  internet.Install (c);

  NS_LOG_INFO ("Create channels.");

  PointToPointHelper p2p;

  p2p.SetDeviceAttribute ("DataRate", StringValue ("10Mbps"));

  p2p.SetChannelAttribute ("Delay", StringValue ("1ms"));

  NetDeviceContainer d0d1 = p2p.Install (n0n1);

  NetDeviceContainer d1d2 = p2p.Install (n1n2);

  NetDeviceContainer d1d3 = p2p.Install (n1n3);

  NetDeviceContainer d1d4 = p2p.Install (n1n4);

  NetDeviceContainer d2d5 = p2p.Install (n2n5);

  NetDeviceContainer d3d5 = p2p.Install (n3n5);

  NetDeviceContainer d4d5 = p2p.Install (n4n5);

  NetDeviceContainer d5d6 = p2p.Install (n5n6);

  NS_LOG_INFO ("Assign IP Addresses.");

  Ipv4AddressHelper ipv4;

  ipv4.SetBase ("10.0.1.0", "255.255.255.0");

  ipv4.Assign (d0d1);

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

  ipv4.Assign (d1d2);

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

  ipv4.Assign (d1d3);

  ipv4.SetBase ("10.1.4.0", "255.255.255.0");

  ipv4.Assign (d1d4);

  ipv4.SetBase ("10.2.5.0", "255.255.255.0");

  ipv4.Assign (d2d5);

  ipv4.SetBase ("10.3.5.0", "255.255.255.0");

  ipv4.Assign (d3d5);

  ipv4.SetBase ("10.4.5.0", "255.255.255.0");

  ipv4.Assign (d4d5);

  ipv4.SetBase ("10.5.6.0", "255.255.255.0");

  ipv4.Assign (d5d6);

  NS_LOG_INFO ("Populate routing tables.");

  Ipv4GlobalRoutingHelper::PopulateRoutingTables ();

  NS_LOG_INFO ("Create Applications.");

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

  OnOffHelper onoff ("ns3::UdpSocketFactory",

                     InetSocketAddress (Ipv4Address ("10.5.6.2"), port));

  onoff.SetConstantRate (DataRate ("100kbps"));

  onoff.SetAttribute ("PacketSize", UintegerValue (500));

  ApplicationContainer apps;

  for (uint32_t i = 0; i < 10; i++)

    {

      apps.Add (onoff.Install (c.Get (0)));

    }

  apps.Add (onoff.Install (c.Get (1)));

  apps.Start (Seconds (1.0));

  apps.Stop (Seconds (5.0));

  PacketSinkHelper sink ("ns3::UdpSocketFactory",

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

  sink.Install (c.Get (6));

  // Trace the right-most (second) interface on nodes 2, 3, and 4

  p2p.EnablePcap ("ecmp-global-routing", 2, 2);

  p2p.EnablePcap ("ecmp-global-routing", 3, 2);

  p2p.EnablePcap ("ecmp-global-routing", 4, 2);

  NS_LOG_INFO ("Run Simulation.");

  Simulator::Run ();

  Simulator::Destroy ();

}

    obj = bld.create_ns3_program( 'ecmp-global-routing',

                                  ['applications', 'point-to-point', 'internet', 'network', 'core'])

    obj.source = 'ecmp-global-routing.cc'

#include "ns3/abort.h"

#include "udp-header.h"

#include "tcp-header.h"

/* see http://www.iana.org/assignments/protocol-numbers */

const uint8_t TCP_PROT_NUMBER = 6;

const uint8_t UDP_PROT_NUMBER = 17;

    .AddAttribute ("FlowEcmpRouting",

                   "Set to true if flows are randomly routed among ECMP; set to false for using only one route consistently",

                   BooleanValue (false),

                   MakeBooleanAccessor (&Ipv4GlobalRouting::m_flowEcmpRouting),

                   MakeBooleanChecker ())

    m_flowEcmpRouting (false),

// This function is used to spread the routing of flows across equal

// cost paths, by calculating an integer based on the five-tuple in the headers

//

// It assumes that if a transport protocol value is specified in the header, 

// that a transport header with port numbers is prepended to the ipPayload 

//

uint32_t

Ipv4GlobalRouting::GetTupleValue (const Ipv4Header &header, Ptr<const Packet> ipPayload)

{

  // We do not care if this value rolls over

  uint32_t tupleValue = header.GetSource ().Get () + 

                        header.GetDestination ().Get () + 

                        header.GetProtocol ();

  switch (header.GetProtocol ())

    {

    case UDP_PROT_NUMBER:

      {

        UdpHeader udpHeader;

        ipPayload->PeekHeader (udpHeader);

        NS_LOG_DEBUG ("Found UDP proto and header: " << 

                       udpHeader.GetSourcePort () << ":" <<  

                       udpHeader.GetDestinationPort ());

        tupleValue += udpHeader.GetSourcePort ();

        tupleValue += udpHeader.GetDestinationPort ();

        break;

      }

    case TCP_PROT_NUMBER:

      {

        TcpHeader tcpHeader;

        ipPayload->PeekHeader (tcpHeader);

        NS_LOG_DEBUG ("Found TCP proto and header: " << 

                       tcpHeader.GetSourcePort () << ":" <<  

                       tcpHeader.GetDestinationPort ());

        tupleValue += tcpHeader.GetSourcePort ();

        tupleValue += tcpHeader.GetDestinationPort ();

        break;

      }

    default:

      {

        NS_LOG_DEBUG ("Udp or Tcp header not found");

        break;

      }

    }

  return tupleValue;

}

  /// Set to true if flows are randomly routed among ECMP; set to false for using only one route consistently

  bool m_flowEcmpRouting;