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

/*

 * Copyright (c) 2007 Georgia Tech Research Corporation

 *

 * 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

 *

 * Author: Raj Bhattacharjea <raj.b@gatech.edu>

 */

#include "ns3/assert.h"

#include "ns3/log.h"

#include "ns3/nstime.h"

#include "ns3/boolean.h"

#include "ns3/object-vector.h"

#include "ns3/packet.h"

#include "ns3/node.h"

#include "ns3/simulator.h"

#include "ns3/ipv4-route.h"

#include "tcp-l4-protocol.h"

#include "tcp-header.h"

#include "ipv4-end-point-demux.h"

#include "ipv4-end-point.h"

#include "ipv4-l3-protocol.h"

#include "tcp-socket-factory-impl.h"

#include "tcp-newreno.h"

#include "rtt-estimator.h"

#include <vector>

#include <sstream>

#include <iomanip>

NS_LOG_COMPONENT_DEFINE ("TcpL4Protocol");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (TcpL4Protocol);

//TcpL4Protocol stuff----------------------------------------------------------

#undef NS_LOG_APPEND_CONTEXT

#define NS_LOG_APPEND_CONTEXT                                   \

  if (m_node) { std::clog << Simulator::Now ().GetSeconds () << " [node " << m_node->GetId () << "] "; } 

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

const uint8_t TcpL4Protocol::PROT_NUMBER = 6;

TypeId 

TcpL4Protocol::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::TcpL4Protocol")

    .SetParent<Ipv4L4Protocol> ()

    .AddConstructor<TcpL4Protocol> ()

    .AddAttribute ("RttEstimatorType",

                   "Type of RttEstimator objects.",

                   TypeIdValue (RttMeanDeviation::GetTypeId()),

                   MakeTypeIdAccessor (&TcpL4Protocol::m_rttTypeId),

                   MakeTypeIdChecker ())

    .AddAttribute ("SocketType",

                   "Socket type of TCP objects.",

                   TypeIdValue (TcpNewReno::GetTypeId()),

                   MakeTypeIdAccessor (&TcpL4Protocol::m_socketTypeId),

                   MakeTypeIdChecker ())

    .AddAttribute ("SocketList", "The list of sockets associated to this protocol.",

                   ObjectVectorValue (),

                   MakeObjectVectorAccessor (&TcpL4Protocol::m_sockets),

                   MakeObjectVectorChecker<TcpSocketBase> ())

    ;

  return tid;

}

TcpL4Protocol::TcpL4Protocol ()

  : m_endPoints (new Ipv4EndPointDemux ())

{

  NS_LOG_FUNCTION_NOARGS ();

  NS_LOG_LOGIC("Made a TcpL4Protocol "<<this);

}

TcpL4Protocol::~TcpL4Protocol ()

{

  NS_LOG_FUNCTION_NOARGS ();

}

void 

TcpL4Protocol::SetNode (Ptr<Node> node)

{

  m_node = node;

}

/* 

 * This method is called by AddAgregate and completes the aggregation

 * by setting the node in the TCP stack, link it to the ipv4 stack and 

 * adding TCP socket factory to the node.

 */

void

TcpL4Protocol::NotifyNewAggregate ()

{

  if (m_node == 0)

    {

      Ptr<Node> node = this->GetObject<Node> ();

      if (node != 0)

        {

          Ptr<Ipv4L3Protocol> ipv4 = this->GetObject<Ipv4L3Protocol> ();

          if (ipv4 != 0)

            {

              this->SetNode (node);

              ipv4->Insert (this);

              Ptr<TcpSocketFactoryImpl> tcpFactory = CreateObject<TcpSocketFactoryImpl> ();

              tcpFactory->SetTcp (this);

              node->AggregateObject (tcpFactory);

              this->SetDownTarget (MakeCallback(&Ipv4L3Protocol::Send, ipv4));

            }

        }

    }

  Object::NotifyNewAggregate ();

}

int 

TcpL4Protocol::GetProtocolNumber (void) const

{

  return PROT_NUMBER;

}

void

TcpL4Protocol::DoDispose (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  for (std::vector<Ptr<TcpSocketBase> >::iterator i = m_sockets.begin (); i != m_sockets.end (); i++)

    {

      *i = 0;

    }

  m_sockets.clear ();

  if (m_endPoints != 0)

    {

      delete m_endPoints;

      m_endPoints = 0;

    }

  m_node = 0;

  m_downTarget.Nullify ();

  Ipv4L4Protocol::DoDispose ();

}

Ptr<Socket>

TcpL4Protocol::CreateSocket (TypeId socketTypeId)

{

  NS_LOG_FUNCTION_NOARGS ();

  ObjectFactory rttFactory;

  ObjectFactory socketFactory;

  rttFactory.SetTypeId(m_rttTypeId);

  socketFactory.SetTypeId(socketTypeId);

  Ptr<RttEstimator> rtt = rttFactory.Create<RttEstimator> ();

  Ptr<TcpSocketBase> socket = socketFactory.Create<TcpSocketBase> ();

  socket->SetNode (m_node);

  socket->SetTcp (this);

  socket->SetRtt (rtt);

  m_sockets.push_back (socket);

  return socket;

}

Ptr<Socket>

TcpL4Protocol::CreateSocket (void)

{

  return CreateSocket (m_socketTypeId);

}

Ipv4EndPoint *

TcpL4Protocol::Allocate (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  return m_endPoints->Allocate ();

}

Ipv4EndPoint *

TcpL4Protocol::Allocate (Ipv4Address address)

{

  NS_LOG_FUNCTION (this << address);

  return m_endPoints->Allocate (address);

}

Ipv4EndPoint *

TcpL4Protocol::Allocate (uint16_t port)

{

  NS_LOG_FUNCTION (this << port);

  return m_endPoints->Allocate (port);

}

Ipv4EndPoint *

TcpL4Protocol::Allocate (Ipv4Address address, uint16_t port)

{

  NS_LOG_FUNCTION (this << address << port);

  return m_endPoints->Allocate (address, port);

}

Ipv4EndPoint *

TcpL4Protocol::Allocate (Ipv4Address localAddress, uint16_t localPort,

                         Ipv4Address peerAddress, uint16_t peerPort)

{

  NS_LOG_FUNCTION (this << localAddress << localPort << peerAddress << peerPort);

  return m_endPoints->Allocate (localAddress, localPort,

                                peerAddress, peerPort);

}

void 

TcpL4Protocol::DeAllocate (Ipv4EndPoint *endPoint)

{

  NS_LOG_FUNCTION (this << endPoint);

  m_endPoints->DeAllocate (endPoint);

}

enum Ipv4L4Protocol::RxStatus

TcpL4Protocol::Receive (Ptr<Packet> packet,

             Ipv4Header const &ipHeader,

             Ptr<Ipv4Interface> incomingInterface)

{

  NS_LOG_FUNCTION (this << packet << ipHeader << incomingInterface);

  TcpHeader tcpHeader;

  if(Node::ChecksumEnabled ())

  {

    tcpHeader.EnableChecksums();

    tcpHeader.InitializeChecksum (ipHeader.GetSource (), ipHeader.GetDestination (), PROT_NUMBER);

  }

  packet->PeekHeader (tcpHeader);

  NS_LOG_LOGIC("TcpL4Protocol " << this

               << " receiving seq " << tcpHeader.GetSequenceNumber()

               << " ack " << tcpHeader.GetAckNumber()

               << " flags "<< std::hex << (int)tcpHeader.GetFlags() << std::dec

               << " data size " << packet->GetSize());

  if(!tcpHeader.IsChecksumOk ())

  {

    NS_LOG_INFO("Bad checksum, dropping packet!");

    return Ipv4L4Protocol::RX_CSUM_FAILED;

  }

  NS_LOG_LOGIC ("TcpL4Protocol "<<this<<" received a packet");

  Ipv4EndPointDemux::EndPoints endPoints =

    m_endPoints->Lookup (ipHeader.GetDestination (), tcpHeader.GetDestinationPort (),

                         ipHeader.GetSource (), tcpHeader.GetSourcePort (),incomingInterface);

  if (endPoints.empty ())

  {

    NS_LOG_LOGIC ("  No endpoints matched on TcpL4Protocol "<<this);

    std::ostringstream oss;

    oss<<"  destination IP: ";

    ipHeader.GetDestination ().Print (oss);

    oss<<" destination port: "<< tcpHeader.GetDestinationPort ()<<" source IP: ";

    ipHeader.GetSource ().Print (oss);

    oss<<" source port: "<<tcpHeader.GetSourcePort ();

    NS_LOG_LOGIC (oss.str ());

    if (!(tcpHeader.GetFlags () & TcpHeader::RST))

      {

        // build a RST packet and send

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

        TcpHeader header;

        if (tcpHeader.GetFlags () & TcpHeader::ACK)

          {

            // ACK bit was set

            header.SetFlags (TcpHeader::RST);

            header.SetSequenceNumber (header.GetAckNumber ());

          }

        else

          {

            header.SetFlags (TcpHeader::RST | TcpHeader::ACK);

            header.SetSequenceNumber (SequenceNumber32 (0));

            header.SetAckNumber (header.GetSequenceNumber () + SequenceNumber32 (1));

          }

        header.SetSourcePort (tcpHeader.GetDestinationPort ());

        header.SetDestinationPort (tcpHeader.GetSourcePort ());

        SendPacket (rstPacket, header, ipHeader.GetDestination (), ipHeader.GetSource ());

        return Ipv4L4Protocol::RX_ENDPOINT_CLOSED;

      }

    else

      {

        return Ipv4L4Protocol::RX_ENDPOINT_CLOSED;

      }

  }

  NS_ASSERT_MSG (endPoints.size() == 1 , "Demux returned more than one endpoint");

  NS_LOG_LOGIC ("TcpL4Protocol "<<this<<" forwarding up to endpoint/socket");

  (*endPoints.begin ())->ForwardUp (packet, ipHeader, tcpHeader.GetSourcePort (), 

                                    incomingInterface);

  return Ipv4L4Protocol::RX_OK;

}

void

TcpL4Protocol::Send (Ptr<Packet> packet, 

           Ipv4Address saddr, Ipv4Address daddr, 

           uint16_t sport, uint16_t dport, Ptr<NetDevice> oif)

{

  NS_LOG_FUNCTION (this << packet << saddr << daddr << sport << dport << oif);

  TcpHeader tcpHeader;

  tcpHeader.SetDestinationPort (dport);

  tcpHeader.SetSourcePort (sport);

  if(Node::ChecksumEnabled ())

  {

    tcpHeader.EnableChecksums();

  }

  tcpHeader.InitializeChecksum (saddr,

                               daddr,

                               PROT_NUMBER);

  tcpHeader.SetFlags (TcpHeader::ACK);

  tcpHeader.SetAckNumber (SequenceNumber32 (0));

  packet->AddHeader (tcpHeader);

  Ptr<Ipv4L3Protocol> ipv4 = 

    m_node->GetObject<Ipv4L3Protocol> ();

  if (ipv4 != 0)

    {

      Ipv4Header header;

      header.SetDestination (daddr);

      header.SetProtocol (PROT_NUMBER);

      Socket::SocketErrno errno_;

      Ptr<Ipv4Route> route;

      Ptr<NetDevice> oif (0); //specify non-zero if bound to a source address

      if (ipv4->GetRoutingProtocol () != 0)

        {

          route = ipv4->GetRoutingProtocol ()->RouteOutput (packet, header, oif, errno_);

        }

      else

        {

          NS_LOG_ERROR ("No IPV4 Routing Protocol");

          route = 0;

        }

      ipv4->Send (packet, saddr, daddr, PROT_NUMBER, route);

    }

}

void

TcpL4Protocol::SendPacket (Ptr<Packet> packet, const TcpHeader &outgoing,

                               Ipv4Address saddr, Ipv4Address daddr, Ptr<NetDevice> oif)

{

  NS_LOG_LOGIC("TcpL4Protocol " << this

              << " sending seq " << outgoing.GetSequenceNumber()

              << " ack " << outgoing.GetAckNumber()

              << " flags " << std::hex << (int)outgoing.GetFlags() << std::dec

              << " data size " << packet->GetSize());

  NS_LOG_FUNCTION (this << packet << saddr << daddr << oif);

  // XXX outgoingHeader cannot be logged

  TcpHeader outgoingHeader = outgoing;

  outgoingHeader.SetLength (5); //header length in units of 32bit words

  /* outgoingHeader.SetUrgentPointer (0); //XXX */

  if(Node::ChecksumEnabled ())

  {

    outgoingHeader.EnableChecksums();

  }

  outgoingHeader.InitializeChecksum(saddr, daddr, PROT_NUMBER);

  packet->AddHeader (outgoingHeader);

  Ptr<Ipv4L3Protocol> ipv4 = 

    m_node->GetObject<Ipv4L3Protocol> ();

  if (ipv4 != 0)

    {

      Ipv4Header header;

      header.SetDestination (daddr);

      header.SetProtocol (PROT_NUMBER);

      Socket::SocketErrno errno_;

      Ptr<Ipv4Route> route;

      if (ipv4->GetRoutingProtocol () != 0)

        {

          route = ipv4->GetRoutingProtocol ()->RouteOutput (packet, header, oif, errno_);

        }

      else

        {

          NS_LOG_ERROR ("No IPV4 Routing Protocol");

          route = 0;

        }

      m_downTarget (packet, saddr, daddr, PROT_NUMBER, route);

    }

  else

    NS_FATAL_ERROR("Trying to use Tcp on a node without an Ipv4 interface");

}

void

TcpL4Protocol::SetDownTarget (Ipv4L4Protocol::DownTargetCallback callback)

{

  m_downTarget = callback;

}

Ipv4L4Protocol::DownTargetCallback

TcpL4Protocol::GetDownTarget (void) const

{

  return m_downTarget;

}

}; // namespace ns3