#include "v4ping.h"

#include "ns3/icmpv4.h"

#include "ns3/assert.h"

#include "ns3/log.h"

#include "ns3/ipv4-address.h"

#include "ns3/socket.h"

#include "ns3/uinteger.h"

#include "ns3/inet-socket-address.h"

#include "ns3/packet.h"

#include "ns3/trace-source-accessor.h"

#include "ns3/simulator.h"

namespace ns3 {

NS_LOG_COMPONENT_DEFINE ("V4Ping");

NS_OBJECT_ENSURE_REGISTERED (V4Ping);

TypeId 

V4Ping::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::V4Ping")

    .SetParent<Application> ()

    .AddConstructor<V4Ping> ()

    .AddAttribute ("Remote", 

		   "The address of the machine we want to ping.",

		   Ipv4AddressValue (),

		   MakeIpv4AddressAccessor (&V4Ping::m_remote),

		   MakeIpv4AddressChecker ())

    .AddTraceSource ("Rtt",

		     "The rtt calculated by the ping.",

		     MakeTraceSourceAccessor (&V4Ping::m_traceRtt));

    ;

  return tid;

}

V4Ping::V4Ping ()

  : m_socket (0),

    m_seq (0)

{}

V4Ping::~V4Ping ()

{}

void

V4Ping::DoDispose (void)

{

  NS_LOG_FUNCTION (this);

  m_socket = 0;

  Application::DoDispose ();

}

uint32_t

V4Ping::GetApplicationId (void) const

{

  Ptr<Node> node = GetNode ();

  for (uint32_t i = 0; i < node->GetNApplications (); ++i)

    {

      if (node->GetApplication (i) == this)

	{

	  return i;

	}

    }

  NS_ASSERT_MSG (false, "forgot to add application to node");

  return 0; // quiet compiler

}

void

V4Ping::Receive (Ptr<Socket> socket)

{

  NS_LOG_FUNCTION (this << socket);

  while (m_socket->GetRxAvailable () > 0)

    {

      Address from;

      Ptr<Packet> p = m_socket->RecvFrom (0xffffffff, 0, from);

      NS_LOG_DEBUG ("recv " << p->GetSize () << " bytes");

      NS_ASSERT (InetSocketAddress::IsMatchingType (from));

      InetSocketAddress realFrom = InetSocketAddress::ConvertFrom (from);

      NS_ASSERT (realFrom.GetPort () == 1); // protocol should be icmp.

      Ipv4Header ipv4;

      p->RemoveHeader (ipv4);

      NS_ASSERT (ipv4.GetProtocol () == 1); // protocol should be icmp.

      Icmpv4Header icmp;

      p->RemoveHeader (icmp);

      if (icmp.GetType () == Icmpv4Header::ECHO_REPLY)

	{

	  Icmpv4Echo echo;

	  p->RemoveHeader (echo);

	  if (echo.GetSequenceNumber () == (m_seq - 1) &&

	      echo.GetIdentifier () == 0)

	    {

		{

		  if (buf[0] == GetNode ()->GetId () &&

		      buf[1] == GetApplicationId ())

		    {

		      int64_t ts = buf[3];

		      ts <<= 32;

		      ts |= buf[2];

		      Time sendTime = TimeStep (ts);

		      NS_ASSERT (Simulator::Now () > sendTime);

		      Time delta = Simulator::Now () - sendTime;

		      m_traceRtt (delta);

		    }

		}

	    }

	}

    }

}

void

V4Ping::Write32 (uint8_t *buffer, uint32_t data)

{

  buffer[0] = (data >> 0) & 0xff;

  buffer[1] = (data >> 8) & 0xff;

  buffer[2] = (data >> 16) & 0xff;

  buffer[3] = (data >> 24) & 0xff;

}

void 

V4Ping::StartApplication (void)

{

  NS_LOG_FUNCTION (this);

  m_socket = Socket::CreateSocket (GetNode (), TypeId::LookupByName ("ns3::Ipv4RawSocketFactory"));

  NS_ASSERT (m_socket != 0);

  m_socket->SetAttribute ("Protocol", UintegerValue (1)); // icmp

  m_socket->SetRecvCallback (MakeCallback (&V4Ping::Receive, this));

  InetSocketAddress src = InetSocketAddress (Ipv4Address::GetAny (), 0);

  int status;

  status = m_socket->Bind (src);

  NS_ASSERT (status != -1);

  InetSocketAddress dst = InetSocketAddress (m_remote, 0);

  status = m_socket->Connect (dst);

  NS_ASSERT (status != -1);

  Ptr<Packet> p = Create<Packet> ();

  Icmpv4Echo echo;

  echo.SetSequenceNumber (m_seq);

  m_seq++;

  echo.SetIdentifier (0);

  //

  // We must write quantities out in some form of network order.  Since there

  // isn't an htonl to work with we just follow the convention in pcap traces

  // (where any difference would show up anyway) and borrow that code.  Don't

  // be too surprised when you see that this is a little endian convention.

  //

  uint8_t data[4 * sizeof(uint32_t)];

  uint32_t tmp = GetNode ()->GetId ();

  Write32 (&data[0 * sizeof(uint32_t)], tmp);

  tmp = GetApplicationId ();

  Write32 (&data[1 * sizeof(uint32_t)], tmp);

  int64_t now = Simulator::Now ().GetTimeStep ();

  tmp = now & 0xffffffff;

  Write32 (&data[2 * sizeof(uint32_t)], tmp);

  now >>= 32;

  tmp = now & 0xffffffff;

  Write32 (&data[3 * sizeof(uint32_t)], tmp);

  Ptr<Packet> dataPacket = Create<Packet> ((uint8_t *) &data, 16);

  echo.SetData (dataPacket);

  p->AddHeader (echo);

  Icmpv4Header header;

  header.SetType (Icmpv4Header::ECHO);

  header.SetCode (0);

  p->AddHeader (header);

  m_socket->Send (p, 0);

}

void 

V4Ping::StopApplication (void)

{

  NS_LOG_FUNCTION (this);

  m_socket->Close ();

}

} // namespace ns3