/* -*- 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

 *

 * based on earlier integration work by Tom Henderson and Sam Jansen.

 * 2008 Florian Westphal <fw@strlen.de>

 */

#include "ns3/assert.h"

#include "ns3/log.h"

#include "ns3/nstime.h"

#include "ns3/packet.h"

#include "ns3/node.h"

#include "ns3/ipv4-route.h"

#include "ns3/object-vector.h"

#include "ns3/string.h"

#include "tcp-header.h"

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

#include "ipv4-end-point.h"

#include "ipv4-l3-protocol.h"

#include "nsc-tcp-l4-protocol.h"

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

#include "nsc-sysctl.h"

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

#include "sim_interface.h"

#include <vector>

#include <sstream>

#include <dlfcn.h>

#include <iomanip>

#include <netinet/in.h>

#include <arpa/inet.h>

namespace ns3 {

NS_LOG_COMPONENT_DEFINE ("NscTcpL4Protocol");

NS_OBJECT_ENSURE_REGISTERED (NscTcpL4Protocol);

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

const uint8_t NscTcpL4Protocol::PROT_NUMBER = 6;

/**

 * \ingroup nsctcp

 * \brief Nsc interface implementation class.

 */

class NscInterfaceImpl : public ISendCallback, public IInterruptCallback 

{

public:

  /**

   * Constructor

   * \param prot the NSC TCP protocol

   */

  NscInterfaceImpl (Ptr<NscTcpL4Protocol> prot);

private:

  /**

   * \brief Invoked by NSCs 'ethernet driver' to re-inject a packet into ns-3.

   *

   * A packet is an octet soup consisting of an IP Header, TCP Header

   * and user payload, if any

   *

   * \param data the data

   * \param datalen the data length

   */

  virtual void send_callback (const void *data, int datalen);

  /**

   * \brief Called by the NSC stack whenever something of interest has happened

   *

   * Examples: when data arrives on a socket, a listen socket

   * has a new connection pending, etc.

   */

  virtual void wakeup ();

  /**

   * \brief Called by the Linux stack RNG initialization

   *

   * Its also used by the cradle code to add a timestamp to

   * printk/printf/debug output.

   */

  virtual void gettime (unsigned int *, unsigned int *);

private:

  Ptr<NscTcpL4Protocol> m_prot; //!< the NSC TCP protocol

};

NscInterfaceImpl::NscInterfaceImpl (Ptr<NscTcpL4Protocol> prot)

  : m_prot (prot)

{

}

void

NscInterfaceImpl::send_callback (const void *data, int datalen)

{

  m_prot->send_callback (data, datalen);

}

void

NscInterfaceImpl::wakeup ()

{

  m_prot->wakeup ();

}

void

NscInterfaceImpl::gettime (unsigned int *sec, unsigned int *usec)

{

  m_prot->gettime (sec,usec);

}

#undef NS_LOG_APPEND_CONTEXT

#define NS_LOG_APPEND_CONTEXT                                   \

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

TypeId 

NscTcpL4Protocol::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::NscTcpL4Protocol")

    .SetParent<IpL4Protocol> ()

    .SetGroupName ("Internet")

    .AddConstructor<NscTcpL4Protocol>()

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

                   ObjectVectorValue (),

                   MakeObjectVectorAccessor (&NscTcpL4Protocol::m_sockets),

                   MakeObjectVectorChecker<NscTcpSocketImpl> ())

    .AddAttribute ("Library",

                   "Set the linux library to be used to create the stack",

                   TypeId::ATTR_GET|TypeId::ATTR_CONSTRUCT,

                   StringValue ("liblinux2.6.26.so"),

                   MakeStringAccessor (&NscTcpL4Protocol::GetNscLibrary,&NscTcpL4Protocol::SetNscLibrary),

                   MakeStringChecker ())

  ;

  return tid;

}

/**

 * \brief External Random number generator

 *

 * \todo make it random...

 *

 * \returns a random number

 */

int external_rand ()

{

  return 1;

}

NscTcpL4Protocol::NscTcpL4Protocol ()

  : m_endPoints (new Ipv4EndPointDemux ()),

    m_nscStack (0),

    m_nscInterface (new NscInterfaceImpl (this)),

    m_softTimer (Timer::CANCEL_ON_DESTROY)

{

  m_dlopenHandle = NULL;

  NS_LOG_LOGIC ("Made a NscTcpL4Protocol "<<this);

}

NscTcpL4Protocol::~NscTcpL4Protocol ()

{

  NS_LOG_FUNCTION (this);

  dlclose (m_dlopenHandle);

}

void

NscTcpL4Protocol::SetNscLibrary (const std::string &soname)

{

  if (soname!="")

    {

      m_nscLibrary = soname;

      NS_ASSERT (!m_dlopenHandle);

      m_dlopenHandle = dlopen (soname.c_str (), RTLD_NOW);

      if (m_dlopenHandle == NULL)

        NS_FATAL_ERROR (dlerror ());

    }

}

std::string 

NscTcpL4Protocol::GetNscLibrary () const

{

  return m_nscLibrary;

}

void 

NscTcpL4Protocol::SetNode (Ptr<Node> node)

{

  m_node = node;

  if (m_nscStack)

    { // stack has already been loaded...

      return;

    }

  NS_ASSERT (m_dlopenHandle);

  FCreateStack create = (FCreateStack)dlsym (m_dlopenHandle, "nsc_create_stack");

  NS_ASSERT (create);

  m_nscStack = create (m_nscInterface, m_nscInterface, external_rand);

  int hzval = m_nscStack->get_hz ();

  NS_ASSERT (hzval > 0);

  m_softTimer.SetFunction (&NscTcpL4Protocol::SoftInterrupt, this);

  m_softTimer.SetDelay (MilliSeconds (1000/hzval));

  m_nscStack->init (hzval);

  // This enables stack and NSC debug messages

  // m_nscStack->set_diagnostic(1000);

  Ptr<Ns3NscStack> nscStack = Create<Ns3NscStack> ();

  nscStack->SetStack (m_nscStack);

  node->AggregateObject (nscStack);

  m_softTimer.Schedule ();

  // its likely no ns-3 interface exits at this point, so

  // we dealy adding the nsc interface until the start of the simulation.

  Simulator::ScheduleNow (&NscTcpL4Protocol::AddInterface, this);

}

void

NscTcpL4Protocol::NotifyNewAggregate ()

{ 

  if (m_node == 0)

    {

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

      if (node != 0)

        {

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

          if (ipv4 != 0 && m_downTarget.IsNull ())

            {

              this->SetNode (node);

              ipv4->Insert (this);

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

              tcpFactory->SetTcp (this);

              node->AggregateObject (tcpFactory);

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

            }

        }

    }

  IpL4Protocol::NotifyNewAggregate ();

}

int 

NscTcpL4Protocol::GetProtocolNumber (void) const

{

  return PROT_NUMBER;

}

int 

NscTcpL4Protocol::GetVersion (void) const

{

  return 2;

}

void

NscTcpL4Protocol::DoDispose (void)

{

  NS_LOG_FUNCTION (this);

  for (std::vector<Ptr<NscTcpSocketImpl> >::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;

  delete m_nscInterface;

  m_nscInterface = 0;

  m_downTarget.Nullify ();

  IpL4Protocol::DoDispose ();

}

Ptr<Socket>

NscTcpL4Protocol::CreateSocket (void)

{

  NS_LOG_FUNCTION (this);

  Ptr<NscTcpSocketImpl> socket = CreateObject<NscTcpSocketImpl> ();

  socket->SetNode (m_node);

  socket->SetTcp (this);

  m_sockets.push_back (socket);

  return socket;

}

Ipv4EndPoint *

NscTcpL4Protocol::Allocate (void)

{

  NS_LOG_FUNCTION (this);

  return m_endPoints->Allocate ();

}

Ipv4EndPoint *

NscTcpL4Protocol::Allocate (Ipv4Address address)

{

  NS_LOG_FUNCTION (this << address);

  return m_endPoints->Allocate (address);

}

Ipv4EndPoint *

NscTcpL4Protocol::Allocate (uint16_t port)

{

  NS_LOG_FUNCTION (this << port);

  return m_endPoints->Allocate (port);

}

Ipv4EndPoint *

NscTcpL4Protocol::Allocate (Ipv4Address address, uint16_t port)

{

  NS_LOG_FUNCTION (this << address << port);

  return m_endPoints->Allocate (address, port);

}

Ipv4EndPoint *

NscTcpL4Protocol::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 

NscTcpL4Protocol::DeAllocate (Ipv4EndPoint *endPoint)

{

  NS_LOG_FUNCTION (this << endPoint);

  // NSC m_endPoints->DeAllocate (endPoint);

}

IpL4Protocol::RxStatus

NscTcpL4Protocol::Receive (Ptr<Packet> packet,

                           Ipv4Header const &header,

                           Ptr<Ipv4Interface> incomingInterface)

{

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

  Ipv4Header ipHeader;

  uint32_t packetSize = packet->GetSize ();

  // The way things work at the moment, the IP header has been removed

  // by the ns-3 IPv4 processing code. However, the NSC stack expects

  // a complete IP packet, so we add the IP header back.

  // Since the original header is already gone, we create a new one

  // based on the information we have.

  ipHeader.SetSource (header.GetSource ());

  ipHeader.SetDestination (header.GetDestination ());

  ipHeader.SetProtocol (PROT_NUMBER);

  ipHeader.SetPayloadSize (packetSize);

  ipHeader.SetTtl (1);

  // all NSC stacks check the IP checksum

  ipHeader.EnableChecksum ();

  packet->AddHeader (ipHeader);

  packetSize = packet->GetSize ();

  uint8_t *buf = new uint8_t[packetSize];

  packet->CopyData (buf, packetSize);

  const uint8_t *data = const_cast<uint8_t *>(buf);

  // deliver complete packet to the NSC network stack

  m_nscStack->if_receive_packet (0, data, packetSize);

  delete[] buf;

  wakeup ();

  return IpL4Protocol::RX_OK;

}

IpL4Protocol::RxStatus

NscTcpL4Protocol::Receive(Ptr<Packet>, Ipv6Header const &, Ptr<Ipv6Interface>)

{

  return IpL4Protocol::RX_ENDPOINT_UNREACH;

}

void NscTcpL4Protocol::SoftInterrupt (void)

{

  m_nscStack->timer_interrupt ();

  m_nscStack->increment_ticks ();

  m_softTimer.Schedule ();

}

void NscTcpL4Protocol::send_callback (const void* data, int datalen)

{

  Ptr<Packet> p;

  uint32_t ipv4Saddr, ipv4Daddr;

  NS_ASSERT (datalen > 20);

  // create packet, without IP header. The TCP header is not touched.

  // Not using the IP header makes integration easier, but it destroys

  // eg. ECN.

  const uint8_t *rawdata = reinterpret_cast<const uint8_t *>(data);

  rawdata += 20; // skip IP header. IP options aren't supported at this time.

  datalen -= 20;

  p = Create<Packet> (rawdata, datalen);

  // we need the real source/destination ipv4 addresses for Send ().

  const uint32_t *ipheader = reinterpret_cast<const uint32_t *>(data);

  ipv4Saddr = *(ipheader+3);

  ipv4Daddr = *(ipheader+4);

  Ipv4Address saddr (ntohl (ipv4Saddr));

  Ipv4Address daddr (ntohl (ipv4Daddr));

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

  NS_ASSERT_MSG (ipv4, "nsc callback invoked, but node has no ipv4 object");

  m_downTarget (p, saddr, daddr, PROT_NUMBER, 0);

  m_nscStack->if_send_finish (0);

}

void NscTcpL4Protocol::wakeup ()

{

  // \todo

  // this should schedule a timer to read from all tcp sockets now... this is

  // an indication that data might be waiting on the socket

  Ipv4EndPointDemux::EndPoints endPoints = m_endPoints->GetAllEndPoints ();

  for (Ipv4EndPointDemux::EndPointsI endPoint = endPoints.begin ();

       endPoint != endPoints.end (); endPoint++) {

      // NSC HACK: (ab)use TcpSocket::ForwardUp for signalling

      (*endPoint)->ForwardUp (NULL, Ipv4Header (), 0, 0);

    }

}

void NscTcpL4Protocol::gettime (unsigned int* sec, unsigned int* usec)

{

  // Only used by the Linux network stack, e.g. during ISN generation

  // and in the kernel rng initialization routine. Also used in Linux

  // printk output.

  Time t = Simulator::Now ();

  int64_t us = t.GetMicroSeconds ();

  *sec = us / (1000*1000);

  *usec = us - *sec * (1000*1000);

}

void NscTcpL4Protocol::AddInterface (void)

{

  Ptr<Ipv4> ip = m_node->GetObject<Ipv4> ();

  const uint32_t nInterfaces = ip->GetNInterfaces ();

  NS_ASSERT_MSG (nInterfaces <= 2, "nsc does not support multiple interfaces per node");

  // start from 1, ignore the loopback interface (HACK)

  // we really don't need the loop, but its here to illustrate

  // how things _should_ be (once nsc can deal with multiple interfaces...)

  for (uint32_t i = 1; i < nInterfaces; i++)

    {

      Ipv4InterfaceAddress ifAddr = ip->GetAddress (i, 0);

      Ipv4Address addr = ifAddr.GetLocal ();

      Ipv4Mask mask = ifAddr.GetMask ();

      uint16_t mtu = ip->GetMtu (i);

      std::ostringstream addrOss, maskOss;

      addr.Print (addrOss);

      mask.Print (maskOss);

      NS_LOG_LOGIC ("if_attach " << addrOss.str ().c_str () << " " << maskOss.str ().c_str () << " " << mtu);

      std::string addrStr = addrOss.str ();

      std::string maskStr = maskOss.str ();

      const char* addrCStr = addrStr.c_str ();

      const char* maskCStr = maskStr.c_str ();

      m_nscStack->if_attach (addrCStr, maskCStr, mtu);

      if (i == 1)

        {

          // The NSC stack requires a default gateway and only supports

          // single-interface nodes.  The below is a hack, but

          // it turns out that we can pass the interface address to nsc as

          // a default gateway.  Bug 1398 has been opened to track this

          // issue (NSC's limitation to single-interface nodes)

          //

          // Previous versions of this code tried to assign the "next"

          // IP address of the subnet but this was found to fail for

          // some use cases in /30 subnets.

          // \todo \bugid{1398} NSC's limitation to single-interface nodes

          m_nscStack->add_default_gateway (addrOss.str ().c_str ());

        }

    }

}

void

NscTcpL4Protocol::SetDownTarget (IpL4Protocol::DownTargetCallback callback)

{

  m_downTarget = callback;