/* -*- 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

 *

 */

/* Test program for multi-interface host, static routing

         Destination host (10.20.1.2)

                 |

                 | 10.20.1.0/24

              DSTRTR 

  10.10.1.0/24 /   \  10.10.2.0/24

              /     \

           Rtr1    Rtr2

 10.1.1.0/24 |      | 10.1.2.0/24

             |      /

              \    /

             Source

*/

#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"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("SocketBoundTcpRoutingExample");

static const uint32_t totalTxBytes = 20000;

static uint32_t currentTxBytes = 0;

static const uint32_t writeSize = 1040;

uint8_t data[writeSize];

void StartFlow (Ptr<Socket>, Ipv4Address, uint16_t);

void WriteUntilBufferFull (Ptr<Socket>, uint32_t);

void SendStuff (Ptr<Socket> sock, Ipv4Address dstaddr, uint16_t port);

void BindSock (Ptr<Socket> sock, Ptr<NetDevice> netdev);

void srcSocketRecv (Ptr<Socket> socket);

void dstSocketRecv (Ptr<Socket> socket);

int 

main (int argc, char *argv[])

{

  // 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);

  Ptr<Node> nSrc = CreateObject<Node> ();

  Ptr<Node> nDst = CreateObject<Node> ();

  Ptr<Node> nRtr1 = CreateObject<Node> ();

  Ptr<Node> nRtr2 = CreateObject<Node> ();

  Ptr<Node> nDstRtr = CreateObject<Node> ();

  NodeContainer c = NodeContainer (nSrc, nDst, nRtr1, nRtr2, nDstRtr);

  InternetStackHelper internet;

  internet.Install (c);

  // Point-to-point links

  NodeContainer nSrcnRtr1 = NodeContainer (nSrc, nRtr1);

  NodeContainer nSrcnRtr2 = NodeContainer (nSrc, nRtr2);

  NodeContainer nRtr1nDstRtr = NodeContainer (nRtr1, nDstRtr);

  NodeContainer nRtr2nDstRtr = NodeContainer (nRtr2, nDstRtr);

  NodeContainer nDstRtrnDst = NodeContainer (nDstRtr, nDst);

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

  PointToPointHelper p2p;

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

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

  NetDeviceContainer dSrcdRtr1 = p2p.Install (nSrcnRtr1);

  NetDeviceContainer dSrcdRtr2 = p2p.Install (nSrcnRtr2);

  NetDeviceContainer dRtr1dDstRtr = p2p.Install (nRtr1nDstRtr);

  NetDeviceContainer dRtr2dDstRtr = p2p.Install (nRtr2nDstRtr);

  NetDeviceContainer dDstRtrdDst = p2p.Install (nDstRtrnDst);

  Ptr<NetDevice> SrcToRtr1=dSrcdRtr1.Get (0);

  Ptr<NetDevice> SrcToRtr2=dSrcdRtr2.Get (0);

  // Later, we add IP addresses.  

  Ipv4AddressHelper ipv4;

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

  Ipv4InterfaceContainer iSrciRtr1 = ipv4.Assign (dSrcdRtr1);

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

  Ipv4InterfaceContainer iSrciRtr2 = ipv4.Assign (dSrcdRtr2);

  ipv4.SetBase ("10.10.1.0", "255.255.255.0");

  Ipv4InterfaceContainer iRtr1iDstRtr = ipv4.Assign (dRtr1dDstRtr);

  ipv4.SetBase ("10.10.2.0", "255.255.255.0");

  Ipv4InterfaceContainer iRtr2iDstRtr = ipv4.Assign (dRtr2dDstRtr);

  ipv4.SetBase ("10.20.1.0", "255.255.255.0");

  Ipv4InterfaceContainer iDstRtrDst = ipv4.Assign (dDstRtrdDst);

  Ptr<Ipv4> ipv4Src = nSrc->GetObject<Ipv4> ();

  Ptr<Ipv4> ipv4Rtr1 = nRtr1->GetObject<Ipv4> ();

  Ptr<Ipv4> ipv4Rtr2 = nRtr2->GetObject<Ipv4> ();

  Ptr<Ipv4> ipv4DstRtr = nDstRtr->GetObject<Ipv4> ();

  Ptr<Ipv4> ipv4Dst = nDst->GetObject<Ipv4> ();

  Ipv4StaticRoutingHelper ipv4RoutingHelper;

  Ptr<Ipv4StaticRouting> staticRoutingSrc = ipv4RoutingHelper.GetStaticRouting (ipv4Src);

  Ptr<Ipv4StaticRouting> staticRoutingRtr1 = ipv4RoutingHelper.GetStaticRouting (ipv4Rtr1);

  Ptr<Ipv4StaticRouting> staticRoutingRtr2 = ipv4RoutingHelper.GetStaticRouting (ipv4Rtr2);

  Ptr<Ipv4StaticRouting> staticRoutingDstRtr = ipv4RoutingHelper.GetStaticRouting (ipv4DstRtr);

  Ptr<Ipv4StaticRouting> staticRoutingDst = ipv4RoutingHelper.GetStaticRouting (ipv4Dst);

  // Create static routes from Src to Dst

  staticRoutingRtr1->AddHostRouteTo (Ipv4Address ("10.20.1.2"), Ipv4Address ("10.10.1.2"), 2);

  staticRoutingRtr2->AddHostRouteTo (Ipv4Address ("10.20.1.2"), Ipv4Address ("10.10.2.2"), 2);

  // Two routes to same destination - setting separate metrics. 

  // You can switch these to see how traffic gets diverted via different routes

  staticRoutingSrc->AddHostRouteTo (Ipv4Address ("10.20.1.2"), Ipv4Address ("10.1.1.2"), 1,5);

  staticRoutingSrc->AddHostRouteTo (Ipv4Address ("10.20.1.2"), Ipv4Address ("10.1.2.2"), 2,10);

  // Creating static routes from DST to Source pointing to Rtr1 VIA Rtr2(!)

  staticRoutingDst->AddHostRouteTo (Ipv4Address ("10.1.1.1"), Ipv4Address ("10.20.1.1"), 1);

  staticRoutingDstRtr->AddHostRouteTo (Ipv4Address ("10.1.1.1"), Ipv4Address ("10.10.2.1"), 2);

  staticRoutingRtr2->AddHostRouteTo (Ipv4Address ("10.1.1.1"), Ipv4Address ("10.1.2.1"), 1);

  staticRoutingDst->AddHostRouteTo (Ipv4Address ("10.1.2.1"), Ipv4Address ("10.20.1.1"), 1);

  staticRoutingDstRtr->AddHostRouteTo (Ipv4Address ("10.1.2.1"), Ipv4Address ("10.10.2.1"), 2);

  staticRoutingRtr2->AddHostRouteTo (Ipv4Address ("10.1.2.1"), Ipv4Address ("10.1.2.1"), 1);

  Ipv4InterfaceAddress ifInAddrSrc=ipv4Src->GetAddress (1,0);

  // There are no apps that can utilize the Socket Option so doing the work directly..

  // Taken from tcp-large-transfer example

  Ptr<Socket> srcSocket1 = Socket::CreateSocket (nSrc, TypeId::LookupByName ("ns3::TcpSocketFactory"));

  Ptr<Socket> srcSocket2 = Socket::CreateSocket (nSrc, TypeId::LookupByName ("ns3::TcpSocketFactory"));

  Ptr<Socket> srcSocket3 = Socket::CreateSocket (nSrc, TypeId::LookupByName ("ns3::TcpSocketFactory"));

  Ptr<Socket> srcSocket4 = Socket::CreateSocket (nSrc, TypeId::LookupByName ("ns3::TcpSocketFactory"));

  uint16_t dstport = 12345;

  Ipv4Address dstaddr ("10.20.1.2");

  PacketSinkHelper sink ("ns3::TcpSocketFactory", InetSocketAddress (Ipv4Address::GetAny(), dstport));

  ApplicationContainer apps = sink.Install (nDst);

  apps.Start (Seconds (0.0));

  apps.Stop (Seconds (10.0));

  p2p.EnablePcapAll ("socket-bound-tcp-static-routing");

  LogComponentEnableAll (LOG_PREFIX_TIME);

  LogComponentEnable ("SocketBoundTcpRoutingExample", LOG_LEVEL_INFO);

  // First packet as normal (goes via Rtr1)

  Simulator::Schedule (Seconds (0.1),&StartFlow, srcSocket1, dstaddr, dstport);

  // Second via Rtr1 explicitly

  Simulator::Schedule (Seconds (1.0),&BindSock, srcSocket2, SrcToRtr1);

  Simulator::Schedule (Seconds (1.1),&StartFlow, srcSocket2, dstaddr, dstport);

  // Third via Rtr2 explicitly

  Simulator::Schedule (Seconds (2.0),&BindSock, srcSocket3, SrcToRtr2);

  Simulator::Schedule (Seconds (2.1),&StartFlow, srcSocket3, dstaddr, dstport);

  // Fourth again as normal (goes via Rtr1)

  Simulator::Schedule (Seconds (3.0),&BindSock, srcSocket4, Ptr<NetDevice>(0));

  Simulator::Schedule (Seconds (3.1),&StartFlow, srcSocket4, dstaddr, dstport);

  // If you uncomment what's below, it results in ASSERT failing since you can't 

  // bind to a socket not existing on a node

  // Simulator::Schedule(Seconds(4.0),&BindSock, srcSocket, dDstRtrdDst.Get(0)); 

  Simulator::Run ();

  Simulator::Destroy ();

  return 0;

}

void BindSock(Ptr<Socket> sock, Ptr<NetDevice> netdev)

{

  sock->BindToNetDevice(netdev);

  return;

}

void StartFlow(Ptr<Socket> localSocket,

               Ipv4Address servAddress,

               uint16_t servPort)

{

  NS_LOG_INFO ("Starting flow at time " <<  Simulator::Now ().GetSeconds ());

  currentTxBytes = 0;

  localSocket->Bind ();

  localSocket->Connect (InetSocketAddress (servAddress, servPort));//connect

  // tell the tcp implementation to call WriteUntilBufferFull again

  // if we blocked and new tx buffer space becomes available

  localSocket->SetSendCallback (MakeCallback (&WriteUntilBufferFull));

  WriteUntilBufferFull (localSocket, localSocket->GetTxAvailable ());

}

void WriteUntilBufferFull (Ptr<Socket> localSocket, uint32_t txSpace)

{

  while (currentTxBytes < totalTxBytes && localSocket->GetTxAvailable () > 0)

    {

      uint32_t left = totalTxBytes - currentTxBytes;

      uint32_t dataOffset = currentTxBytes % writeSize;

      uint32_t toWrite = writeSize - dataOffset;

      toWrite = std::min (toWrite, left);

      toWrite = std::min (toWrite, localSocket->GetTxAvailable ());

      int amountSent = localSocket->Send (&data[dataOffset], toWrite, 0);

      if(amountSent < 0)

        {

          // we will be called again when new tx space becomes available.

          return;

        }

      currentTxBytes += amountSent;

    }

  localSocket->Close ();

}