/* -*- 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

 *

 * Contributed by:  Luis Cortes (cortes@gatech.edu)

 */

// This script exercises global routing code in a mixed point-to-point

// and csma/cd environment.  We bring up and down interfaces and observe

// the effect on global routing.  We explicitly enable the attribute

// to respond to interface events, so that routes are recomputed

// automatically.

//

// Network topology

//

//  n0

//     \ p-p

//      \          (shared csma/cd)

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

//      /            |        | 

//     / p-p        n4        n5 ---------- n6

//   n1                             p-p

//   |                                      |

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

//                p-p

//

// - at time 1 CBR/UDP flow from n1 to n6's IP address on the n5/n6 link

// - at time 10, start similar flow from n1 to n6's address on the n1/n6 link

//

//  Order of events

//  At pre-simulation time, configure global routes.  Shortest path from

//  n1 to n6 is via the direct point-to-point link

//  At time 1s, start CBR traffic flow from n1 to n6

//  At time 2s, set the n1 point-to-point interface to down.  Packets

//    will be diverted to the n1-n2-n5-n6 path

//  At time 4s, re-enable the n1/n6 interface to up.  n1-n6 route restored.

//  At time 6s, set the n6-n1 point-to-point Ipv4 interface to down (note, this

//    keeps the point-to-point link "up" from n1's perspective).  Traffic will

//    flow through the path n1-n2-n5-n6

//  At time 8s, bring the interface back up.  Path n1-n6 is restored

//  At time 10s, stop the first flow.

//  At time 11s, start a new flow, but to n6's other IP address (the one

//    on the n1/n6 p2p link)

//  At time 12s, bring the n1 interface down between n1 and n6.  Packets

//    will be diverted to the alternate path

//  At time 14s, re-enable the n1/n6 interface to up.  This will change 

//    routing back to n1-n6 since the interface up notification will cause

//    a new local interface route, at higher priority than global routing

//  At time 16s, stop the second flow.

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

#include <iostream>

#include <fstream>

#include <string>

#include <cassert>

#include "ns3/core-module.h"

#include "ns3/network-module.h"

#include "ns3/csma-module.h"

#include "ns3/internet-module.h"

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

#include "ns3/applications-module.h"

#include "ns3/ipv4-global-routing-helper.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("DynamicGlobalRoutingExample");

int 

main (int argc, char *argv[])

{

  // The below value configures the default behavior of global routing.

  // By default, it is disabled.  To respond to interface events, set to true

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

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

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

  CommandLine cmd;

  cmd.Parse (argc, argv);

  NS_LOG_INFO ("Create nodes.");

  NodeContainer c;

  c.Create (7);

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

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

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

  NodeContainer n1n6 = NodeContainer (c.Get (1), c.Get (6));

  NodeContainer n2345 = NodeContainer (c.Get (2), c.Get (3), c.Get (4), c.Get (5));

  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 d1d6 = p2p.Install (n1n6);

  NetDeviceContainer d1d2 = p2p.Install (n1n2);

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

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

  NetDeviceContainer d5d6 = p2p.Install (n5n6);

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

  CsmaHelper csma;

  csma.SetChannelAttribute ("DataRate", StringValue ("5Mbps"));

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

  NetDeviceContainer d2345 = csma.Install (n2345);

  // Later, we add IP addresses.

  NS_LOG_INFO ("Assign IP Addresses.");

  Ipv4AddressHelper ipv4;

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

  ipv4.Assign (d0d2);

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

  ipv4.Assign (d1d2);

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

  Ipv4InterfaceContainer i5i6 = ipv4.Assign (d5d6);

  ipv4.SetBase ("10.250.1.0", "255.255.255.0");

  ipv4.Assign (d2345);

  ipv4.SetBase ("172.16.1.0", "255.255.255.0");

  Ipv4InterfaceContainer i1i6 = ipv4.Assign (d1d6);

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

  // tables in the nodes.

  Ipv4GlobalRoutingHelper::PopulateRoutingTables ();

  // 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",

                     InetSocketAddress (i5i6.GetAddress (1), port));

  onoff.SetConstantRate (DataRate ("2kbps"));

  onoff.SetAttribute ("PacketSize", UintegerValue (50));

  ApplicationContainer apps = onoff.Install (c.Get (1));

  apps.Start (Seconds (1.0));

  apps.Stop (Seconds (10.0));

  // Create a second OnOff application to send UDP datagrams of size

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

  OnOffHelper onoff2 ("ns3::UdpSocketFactory",

                      InetSocketAddress (i1i6.GetAddress (1), port));

  onoff2.SetAttribute ("OnTime", StringValue ("ns3::ConstantRandomVariable[Constant=1]"));

  onoff2.SetAttribute ("OffTime", StringValue ("ns3::ConstantRandomVariable[Constant=0]"));

  onoff2.SetAttribute ("DataRate", StringValue ("2kbps"));

  onoff2.SetAttribute ("PacketSize", UintegerValue (50));

  ApplicationContainer apps2 = onoff2.Install (c.Get (1));

  apps2.Start (Seconds (11.0));

  apps2.Stop (Seconds (16.0));

  // Create an optional packet sink to receive these packets

  PacketSinkHelper sink ("ns3::UdpSocketFactory",

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

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

  apps.Start (Seconds (1.0));

  apps.Stop (Seconds (10.0));

  PacketSinkHelper sink2 ("ns3::UdpSocketFactory",

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

  apps2 = sink2.Install (c.Get (6));

  apps2.Start (Seconds (11.0));

  apps2.Stop (Seconds (16.0));

  AsciiTraceHelper ascii;

  Ptr<OutputStreamWrapper> stream = ascii.CreateFileStream ("dynamic-global-routing.tr");

  p2p.EnableAsciiAll (stream);

  csma.EnableAsciiAll (stream);

  internet.EnableAsciiIpv4All (stream);

  p2p.EnablePcapAll ("dynamic-global-routing");

  csma.EnablePcapAll ("dynamic-global-routing", false);

  Ptr<Node> n1 = c.Get (1);

  Ptr<Ipv4> ipv41 = n1->GetObject<Ipv4> ();

  // The first ifIndex is 0 for loopback, then the first p2p is numbered 1,

  // then the next p2p is numbered 2

  uint32_t ipv4ifIndex1 = 2;

  Simulator::Schedule (Seconds (2),&Ipv4::SetDown,ipv41, ipv4ifIndex1);

  Simulator::Schedule (Seconds (4),&Ipv4::SetUp,ipv41, ipv4ifIndex1);

  Ptr<Node> n6 = c.Get (6);

  Ptr<Ipv4> ipv46 = n6->GetObject<Ipv4> ();

  // The first ifIndex is 0 for loopback, then the first p2p is numbered 1,

  // then the next p2p is numbered 2

  uint32_t ipv4ifIndex6 = 2;

  Simulator::Schedule (Seconds (6),&Ipv4::SetDown,ipv46, ipv4ifIndex6);

  Simulator::Schedule (Seconds (8),&Ipv4::SetUp,ipv46, ipv4ifIndex6);

  Simulator::Schedule (Seconds (12),&Ipv4::SetDown,ipv41, ipv4ifIndex1);

  Simulator::Schedule (Seconds (14),&Ipv4::SetUp,ipv41, ipv4ifIndex1);

  // Trace routing tables 

  Ipv4GlobalRoutingHelper g;

  Ptr<OutputStreamWrapper> routingStream = Create<OutputStreamWrapper> ("dynamic-global-routing.routes", std::ios::out);

  g.PrintRoutingTableAllAt (Seconds (12), routingStream);

  NS_LOG_INFO ("Run Simulation.");

  Simulator::Run ();

  Simulator::Destroy ();

  NS_LOG_INFO ("Done.");

}