tcp-example

output

$ tcpdump -qns 0 -A -r ./tcp-transfer-0-0.pcap
reading from file ./tcp-transfer-0-0.pcap, link-type PPP (PPP)
09:00:00.000000 IP 10.1.3.1.49153 > 10.1.3.2.80: tcp 0
.!E..8....@...
...
......P....................
...........
09:00:00.020079 IP 10.1.3.2.80 > 10.1.3.1.49153: tcp 0
.!E..(....@...
...
....P..........P.......
09:00:00.020079 IP 10.1.3.1.49153 > 10.1.3.2.80: tcp 0
.!E..(....@...
...
......P........P.......
$ tcpdump -qns 0 -A -r ./tcp-transfer-1-0.pcap
reading from file ./tcp-transfer-1-0.pcap, link-type PPP (PPP)
09:00:00.010046 IP 10.1.3.1.49153 > 10.1.3.2.80: tcp 0
.!E..8....@...
...
......P....................
...........
09:00:00.010046 IP 10.1.3.2.80 > 10.1.3.1.49153: tcp 0
.!E..(....@...
...
....P..........P.......
09:00:00.030113 IP 10.1.3.1.49153 > 10.1.3.2.80: tcp 0
.!E..(....@...
...
......P........P.......

tcp-transfer.cpp

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

#include <iostream>
#include <fstream>
#include <string>

#include "ns3/core-module.h"
#include "ns3/applications-module.h"
#include "ns3/network-module.h"
#include "ns3/internet-module.h"
#include "ns3/point-to-point-module.h"
#include "ns3/ipv4-global-routing-helper.h"

using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("TcpTransfer");

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

void WriteUntilBufferFull (Ptr<Socket> localSocket, uint32_t txSpace);
static const uint32_t totalTxBytes = 10000;
static const uint32_t writeSize = 1040;
static uint32_t currentTxBytes = 0;
uint8_t data[writeSize];

int main (int argc, char *argv[])
{

  NodeContainer n0n1;
  n0n1.Create (2);

  PointToPointHelper p2p;
  p2p.SetDeviceAttribute ("DataRate", DataRateValue (DataRate (10000000)));
  p2p.SetChannelAttribute ("Delay", TimeValue (MilliSeconds (10)));

  // And then install devices and channels connecting our topology.
  NetDeviceContainer dev0 = p2p.Install (n0n1);

  // Now add ip/tcp stack to all nodes.
  InternetStackHelper internet;
  internet.InstallAll ();

  // Later, we add IP addresses.
  Ipv4AddressHelper ipv4;
  ipv4.SetBase ("10.1.3.0", "255.255.255.0");
  Ipv4InterfaceContainer ipInterfs = ipv4.Assign (dev0);

  Ipv4GlobalRoutingHelper::PopulateRoutingTables ();

  uint16_t servPort = 80;

  Ptr<Socket> localSocket = Socket::CreateSocket (n0n1.Get(0), TcpSocketFactory::GetTypeId());
  localSocket->Bind ();
  Simulator::ScheduleNow (&StartFlow, localSocket, ipInterfs.GetAddress(1), servPort);
  localSocket->SetAttribute("SndBufSize", UintegerValue(4096));

  //Ask for ASCII and pcap traces of network traffic
  AsciiTraceHelper ascii;
  p2p.EnableAsciiAll (ascii.CreateFileStream ("tcp-transfer.tr"));
  p2p.EnablePcapAll ("tcp-transfer");

  // Finally, set up the simulator to run.  The 1000 second hard limit is a
  // failsafe in case some change above causes the simulation to never end
  Simulator::Stop (Seconds (1000));
  Simulator::Run ();
  Simulator::Destroy ();
}

void StartFlow (Ptr<Socket> localSocket,
                Ipv4Address servAddress,
                uint16_t servPort)
{
  localSocket->Connect (InetSocketAddress (servAddress, servPort));
  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 ();
}