Attachment #1019 for bug #903

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

/*
 * Copyright (c) 2010 The Boeing Company
 *
 * 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: Tom Goff <thomas.goff@boeing.com>
 */

#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>

#include "ns3/log.h"
#include "ns3/fatal-error.h"
#include "ns3/simple-ref-count.h"
#include "ns3/system-thread.h"
#include "ns3/simulator.h"

#include "unix-fd-reader.h"

NS_LOG_COMPONENT_DEFINE ("FdReader");

namespace ns3 {

FdReader::FdReader ()
  : m_fd (-1), m_readCallback (0), m_readThread (0), m_stop (false),
    m_destroyEvent ()
{
  m_evpipe[0] = -1;
  m_evpipe[1] = -1;
}

FdReader::~FdReader ()
{
  Stop ();
}

void FdReader::Start (int fd, Callback<void, uint8_t *, ssize_t> readCallback)
{
  int tmp;

  NS_ASSERT_MSG (m_readThread == 0, "read thread already exists");

  // create a pipe for inter-thread event notification
  tmp = pipe (m_evpipe);
  if (tmp == -1)
    {
      NS_FATAL_ERROR ("pipe() failed: " << strerror (errno));
    }

  // make the read end non-blocking
  tmp = fcntl(m_evpipe[0], F_GETFL);
  if (tmp == -1)
    {
      NS_FATAL_ERROR ("fcntl() failed: " << strerror (errno));
    }
  if (fcntl(m_evpipe[0], F_SETFL, tmp | O_NONBLOCK) == -1)
    {
      NS_FATAL_ERROR ("fcntl() failed: " << strerror (errno));
    }

  m_fd = fd;
  m_readCallback = readCallback;

  //
  // We're going to spin up a thread soon, so we need to make sure we have
  // a way to tear down that thread when the simulation stops.  Do this by
  // scheduling a "destroy time" method to make sure the thread exits before
  // proceeding.
  //
  if (! m_destroyEvent.IsRunning ())
    {
      // hold a reference to ensure that this object is not
      // deallocated before the destroy-time event fires
      this->Ref ();
      m_destroyEvent =
        Simulator::ScheduleDestroy (&FdReader::DestroyEvent, this);
    }

  //
  // Now spin up a thread to read from the fd
  //
  NS_LOG_LOGIC ("Spinning up read thread");

  m_readThread = Create<SystemThread> (MakeCallback (&FdReader::Run, this));
  m_readThread->Start ();
}

void FdReader::DestroyEvent (void)
{
  Stop ();
  this->Unref ();
}

void FdReader::Stop (void)
{
  m_stop = true;

  // signal the read thread and close the write end of the event pipe
  if (m_evpipe[1] != -1)
    {
      char zero = 0;
      ssize_t len = write (m_evpipe[1], &zero, sizeof (zero));
      if (len != sizeof (zero))
        NS_LOG_WARN ("incomplete write(): " << strerror (errno));
      close (m_evpipe[1]);
      m_evpipe[1] = -1;
    }

  // join the read thread
  if (m_readThread != 0)
    {
      m_readThread->Join ();
      m_readThread = 0;
    }

  // close the read end of the event pipe
  if (m_evpipe[0] != -1)
    {
      close (m_evpipe[0]);
      m_evpipe[0] = -1;
    }

  // reset everything else
  m_fd = -1;
  m_readCallback.Nullify ();
  m_stop = false;
}

// This runs in a separate thread
void FdReader::Run (void)
{
  int nfds;
  fd_set rfds;

  nfds = (m_fd > m_evpipe[0] ? m_fd : m_evpipe[0]) + 1;

  FD_ZERO (&rfds);
  FD_SET (m_fd, &rfds);
  FD_SET (m_evpipe[0], &rfds);

  for (;;)
    {
      int r;
      fd_set readfds = rfds;

      r = select (nfds, &readfds, NULL, NULL, NULL);
      if (r == -1 && errno != EINTR)
        {
          NS_FATAL_ERROR ("select() failed: " << strerror (errno));
	}

      if (FD_ISSET (m_evpipe[0], &readfds))
        {
          // drain the event pipe
          ssize_t len;
          for (;;)
            {
              char buf[1024];
              len = read (m_evpipe[0], buf, sizeof (buf));
              if (len == 0)
                {
                  NS_FATAL_ERROR ("event pipe closed");
                }
              if (len < 0)
                {
                  break;
                }
            }

          if (len < 0 && errno != EAGAIN && errno != EWOULDBLOCK)
            {
              NS_LOG_WARN ("read() failed: " << strerror (errno));
              break;
            }
	}

      if (m_stop)
        {
          // this thread is done
          break;
        }

      if (FD_ISSET (m_fd, &readfds))
        {
          struct FdReader::Data data = DoRead ();
          // reading stops when m_len is zero
          if (data.m_len == 0)
            {
              break;
            }
          // the callback is only called when m_len is positive (data
          // is ignored if m_len is negative)
          else if (data.m_len > 0)
            {
              m_readCallback (data.m_buf, data.m_len);
            }
        }
    }
}

} // namespace ns3




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

/*
 * Copyright (c) 2010 The Boeing Company
 *
 * 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: Tom Goff <thomas.goff@boeing.com>
 */

#ifndef UNIX_FD_READER_H
#define UNIX_FD_READER_H

#include <stdint.h>

#include "ns3/callback.h"
#include "ns3/system-thread.h"
#include "ns3/event-id.h"

namespace ns3 {

/**
 * \brief A class that asynchronously reads from a file descriptor.
 *
 * This class can be used to start a system thread that reads from a
 * given file descriptor and invokes a given callback when data is
 * received.  This class handles thread management automatically but
 * the \p DoRead() method must be implemented by a subclass.
 */
class FdReader : public SimpleRefCount<FdReader>
{
public:
  FdReader();
  ~FdReader();

  /**
   * Start a new read thread.
   *
   * \param fd A valid file descriptor open for reading.
   *
   * \param readCallback A callback to invoke when new data is
   * available.
   */
  void Start (int fd, Callback<void, uint8_t *, ssize_t> readCallback);

  /**
   * Stop the read thread and reset internal state.  This does not
   * close the file descriptor used for reading.
   */
  void Stop (void);

protected:

  /**
   * \internal
   * \brief A structure representing data read.
   */
  struct Data
  {
    Data () : m_buf (0), m_len (0) {}
    Data (uint8_t *buf, ssize_t len) : m_buf (buf), m_len (len) {}
    uint8_t *m_buf;
    ssize_t m_len;
  };

  /**
   * \internal
   * \brief The read implementation.
   *
   * The value of \p m_len returned controls further processing.  The
   * callback function is only invoked when \p m_len is positive; any
   * data read is not processed when \p m_len is negative; reading
   * stops when \p m_len is zero.
   *
   * The management of memory associated with \p m_buf must be
   * compatible with the read callback.
   *
   * \return A structure representing what was read.
   */
  virtual FdReader::Data DoRead (void) = 0;

  /**
   * \internal
   * \brief The file descriptor to read from.
   */
  int m_fd;

private:

  void Run (void);
  void DestroyEvent (void);

  Callback<void, uint8_t *, ssize_t> m_readCallback;
  Ptr<SystemThread> m_readThread;
  int m_evpipe[2];           // pipe used to signal events between threads
  bool m_stop;               // true means the read thread should stop
  EventId m_destroyEvent;
};

} // namespace ns3

#endif	// UNIX_FD_READER_H




            'unix-system-thread.cc',
            'unix-system-mutex.cc',
            'unix-system-condition.cc',
            'unix-fd-reader.cc',
            ])
        core.uselib = 'PTHREAD'
        headers.source.extend([
                'system-mutex.h',
                'system-thread.h',
                'system-condition.h',
                'unix-fd-reader.h',
                ])

    if bld.env['ENABLE_GSL']:




#include "ns3/ipv4.h"
#include "ns3/simulator.h"
#include "ns3/realtime-simulator-impl.h"
#include "ns3/unix-fd-reader.h"
#include "ns3/uinteger.h"

#include <sys/wait.h>


namespace ns3 {

FdReader::Data TapBridgeFdReader::DoRead (void)
{
  NS_LOG_FUNCTION_NOARGS ();

  uint32_t bufferSize = 65536;
  uint8_t *buf = (uint8_t *)malloc (bufferSize);
  NS_ABORT_MSG_IF (buf == 0, "malloc() failed");

  NS_LOG_LOGIC ("Calling read on tap device fd " << m_fd);
  ssize_t len = read (m_fd, buf, bufferSize);
  if (len <= 0)
    {
      NS_LOG_INFO ("TapBridgeFdReader::DoRead(): done");
      free (buf);
      buf = 0;
      len = 0;
    }

  return FdReader::Data (buf, len);
}

#define TAP_MAGIC 95549

NS_OBJECT_ENSURE_REGISTERED (TapBridge);

  m_sock (-1),
  m_startEvent (),
  m_stopEvent (),
  m_fdReader (0),
  m_ns3AddressRewritten (false)
{
  NS_LOG_FUNCTION_NOARGS ();

{
  NS_LOG_FUNCTION_NOARGS ();

  StopTapDevice ();

  delete [] m_packetBuffer;
  m_packetBuffer = 0;


  //
  // Now spin up a read thread to read packets from the tap device.
  //
  NS_ABORT_MSG_IF (m_fdReader != 0,"TapBridge::StartTapDevice(): Receive thread is already running");
  NS_LOG_LOGIC ("Spinning up read thread");

  m_fdReader = Create<TapBridgeFdReader> ();
  m_fdReader->Start (m_sock, MakeCallback (&TapBridge::ReadCallback, this));
}

void

{
  NS_LOG_FUNCTION_NOARGS ();

  if (m_fdReader != 0)
    {
      m_fdReader->Stop ();
      m_fdReader = 0;
    }

  if (m_sock != -1)
    {
      close (m_sock);
      m_sock = -1;
    }
}

void

}

void
TapBridge::ReadCallback (uint8_t *buf, ssize_t len)
{
  NS_LOG_FUNCTION_NOARGS ();

  NS_ASSERT_MSG (buf != 0, "invalid buf argument");
  NS_ASSERT_MSG (len > 0, "invalid len argument");

  //
  // It's important to remember that we're in a completely different thread
  // than the simulator is running in.  We need to synchronize with that
  // other thread to get the packet up into ns-3.  What we will need to do
  // is to schedule a method to deal with the packet using the multithreaded
  // simulator we are most certainly running.  However, I just said it -- we
  // are talking about two threads here, so it is very, very dangerous to do
  // any kind of reference counting on a shared object.  Just don't do it.
  // So what we're going to do is pass the buffer allocated on the heap
  // into the ns-3 context thread where it will create the packet.
  //
  int32_t len = -1;

  NS_LOG_INFO ("TapBridge::ReadCallback(): Received packet on node " << m_nodeId);
  NS_LOG_INFO ("TapBridge::ReadCallback(): Scheduling handler");
  NS_ASSERT_MSG (m_rtImpl, "TapBridge::ReadCallback(): Realtime simulator implementation pointer not set");
  m_rtImpl->ScheduleRealtimeNowWithContext (m_nodeId, MakeEvent (&TapBridge::ForwardToBridgedDevice, this, buf, len));
      NS_ABORT_MSG_IF (buf == 0, "TapBridge::ReadThread(): malloc packet buffer failed");
      NS_LOG_LOGIC ("Calling read on tap device socket fd " << m_sock);
      len = read (m_sock, buf, bufferSize);

      if (len == -1)
        {
          NS_LOG_INFO ("TapBridge::ReadThread(): Returning");
          free (buf);
          buf = 0;
          return;
        }

      NS_LOG_INFO ("TapBridge::ReadThread(): Received packet on node " << m_nodeId);
      NS_LOG_INFO ("TapBridge::ReadThread(): Scheduling handler");
      NS_ASSERT_MSG (m_rtImpl, "EmuNetDevice::ReadThread(): Realtime simulator implementation pointer not set");
      m_rtImpl->ScheduleRealtimeNowWithContext (m_nodeId, MakeEvent (&TapBridge::ForwardToBridgedDevice, this, buf, len));
      buf = 0;
    }
}

void
TapBridge::ForwardToBridgedDevice (uint8_t *buf, ssize_t len)
{
  NS_LOG_FUNCTION (buf << len);





#include "ns3/data-rate.h"
#include "ns3/ptr.h"
#include "ns3/mac48-address.h"
#include "ns3/unix-fd-reader.h"
#include "ns3/realtime-simulator-impl.h"

namespace ns3 {

class TapBridgeFdReader : public FdReader
{
private:
  FdReader::Data DoRead (void);
};

class Node;

/**

  /**
   * \internal
   *
   * Callback to process packets that are read
   */
  void ReadCallback (uint8_t *buf, ssize_t len);

  /*
   * \internal

   *            received from the host.
   * \param buf The length of the buffer.
   */
  void ForwardToBridgedDevice (uint8_t *buf, ssize_t len);

  /**
   * \internal

   * The socket (actually interpreted as fd) to use to talk to the Tap device on
   * the real internet host.
   */
  int m_sock;

  /**
   * \internal

  /**
   * \internal
   *
   * Includes the ns-3 read thread used to do blocking reads on the fd
   * corresponding to the host device.
   */
  Ptr<TapBridgeFdReader> m_fdReader;

  /**
   * \internal

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