event.c

OpenVPN is a robust and highly flexible tunneling application that uses all of the encryption, authe

{
  struct po_set *pos = (struct po_set *) es;
  ASSERT (pos->fast);
  pos->n_events = 0;
}

static void
po_del (struct event_set *es, event_t event)
{
  struct po_set *pos = (struct po_set *) es;
  ASSERT (!pos->fast);
  ASSERT (0); // JYFIXME -- implement po_del
}

static void
po_ctl (struct event_set *es, event_t event, unsigned int rwflags, void *arg)
{
  struct po_set *pos = (struct po_set *) es;

  msg (D_EVENT_WAIT, "PO_CTL rwflags=0x%04x ev=%d arg=" ptr_format,
       rwflags, (int)event, (ptr_type)arg);

  if (pos->fast)
    {
      if (pos->n_events < pos->capacity)
	{
	  struct pollfd *pfdp = &pos->events[pos->n_events];
	  pfdp->fd = event;
	  pfdp->events = pfdp->revents = 0;
	  pos->args[pos->n_events] = arg;

	  if (rwflags & EVENT_WRITE)
	    pfdp->events |= POLLOUT;
	  if (rwflags & EVENT_READ)
	    pfdp->events |= (POLLIN|POLLPRI);

	  ++pos->n_events;
	}
      else
	goto err;
    }
  else
    {
      ASSERT (0); // JYFIXME -- implement po_ctl for !fast
    }
  return;

 err:
  msg (D_EVENT_ERRORS, "Error: poll: too many I/O wait events");
}

static int
po_wait (struct event_set *es, const struct timeval *tv, struct event_set_return *out, int outlen)
{
  struct po_set *pos = (struct po_set *) es;
  int stat;

  stat = poll (pos->events, pos->n_events, tv_to_ms_timeout (tv));

  // JYFIXME -- show extra debug info after poll() call
#if 0
  msg (D_EVENT_WAIT, "PO_WAIT DEBUG stat=%d pos->n_events=%d",
       stat, pos->n_events);
#endif

  ASSERT (stat <= pos->n_events);

  if (stat > 0)
    {
      int i, j=0;
      const struct pollfd *pfdp = pos->events;
      for (i = 0; i < pos->n_events && j < outlen; ++i)
	{
	  if (pfdp->revents & (POLLIN|POLLPRI|POLLERR|POLLHUP|POLLOUT))
	    {
	      out->rwflags = 0;
	      if (pfdp->revents & (POLLIN|POLLPRI|POLLERR|POLLHUP))
		out->rwflags |= EVENT_READ;
	      if (pfdp->revents & POLLOUT)
		out->rwflags |= EVENT_WRITE;
	      out->arg = pos->args[i];
	      msg (D_EVENT_WAIT, "PO_WAIT[%d,%d] fd=%d rev=0x%08x rwflags=0x%04x arg=" ptr_format,
		   i, j, pfdp->fd, pfdp->revents, out->rwflags, (ptr_type)out->arg);
	      ++out;
	      ++j;
	    }
	  ++pfdp;
	}
      return j;
    }
  return stat;
}

static struct event_set *
po_init (int *maxevents, unsigned int flags)
{
  struct po_set *pos;

  msg (D_EVENT_WAIT, "PO_INIT maxevents=%d flags=0x%08x", *maxevents, flags);

  ALLOC_OBJ_CLEAR (pos, struct po_set);

  /* set dispatch functions */
  pos->func.free = po_free;
  pos->func.reset = po_reset;
  pos->func.del = po_del;
  pos->func.ctl = po_ctl;
  pos->func.wait = po_wait;

  if (flags & EVENT_METHOD_FAST)
    pos->fast = true;

  pos->n_events = 0;

  /* Figure our event capacity */
  ASSERT (*maxevents > 0);
  pos->capacity = *maxevents;

  /* Allocate space for pollfd structures to be passed to poll() */
  ALLOC_ARRAY_CLEAR (pos->events, struct pollfd, pos->capacity);

  /* Allocate space for event_set_return objects */
  ALLOC_ARRAY_CLEAR (pos->args, void *, pos->capacity);

  return (struct event_set *) pos;
}
#endif /* POLL */

#if SELECT

struct se_set
{
  struct event_set_functions func;
  bool fast;
  fd_set readfds;
  fd_set writefds;
  void **args;
  int maxfd;
  int capacity;
};

static void
se_free (struct event_set *es)
{
  struct se_set *ses = (struct se_set *) es;
  free (ses->args);
  free (ses);
}

static void
se_reset (struct event_set *es)
{
  struct se_set *ses = (struct se_set *) es;
  int i;
  ASSERT (ses->fast);
  
  FD_ZERO (&ses->readfds);
  FD_ZERO (&ses->writefds);
  for (i = 0; i <= ses->maxfd; ++i)
    ses->args[i] = NULL;
  ses->maxfd = -1;
}

static void
se_del (struct event_set *es, event_t event)
{
  struct se_set *ses = (struct se_set *) es;
  ASSERT (!ses->fast);

  if (event >= 0 && event < ses->capacity)
    {
      FD_CLR (event, &ses->readfds);
      FD_CLR (event, &ses->writefds);
      ses->args[event] = NULL;
    }
  else
    msg (D_EVENT_ERRORS, "Error: select/se_del: too many I/O wait events");
  return;
}

static void
se_ctl (struct event_set *es, event_t event, unsigned int rwflags, void *arg)
{
  struct se_set *ses = (struct se_set *) es;

  msg (D_EVENT_WAIT, "SE_CTL rwflags=0x%04x ev=%d arg=" ptr_format,
       rwflags, (int)event, (ptr_type)arg);

  if (event >= 0 && event < ses->capacity)
    {
      ses->maxfd = max_int (event, ses->maxfd);
      ses->args[event] = arg;
      if (ses->fast)
	{
	  if (rwflags & EVENT_READ)
	    FD_SET (event, &ses->readfds);
	  if (rwflags & EVENT_WRITE)
	    FD_SET (event, &ses->writefds);
	}
      else
	{
	  if (rwflags & EVENT_READ)
	    FD_SET (event, &ses->readfds);
	  else
	    FD_CLR (event, &ses->readfds);
	  if (rwflags & EVENT_WRITE)
	    FD_SET (event, &ses->writefds);
	  else
	    FD_CLR (event, &ses->writefds);
	}
    }
  else
    {
      msg (D_EVENT_ERRORS, "Error: select: too many I/O wait events");
    }
}

static int
se_wait_return (struct se_set *ses,
		fd_set *read,
		fd_set *write,
		struct event_set_return *out,
		int outlen)
{
  int i, j = 0;
  for (i = 0; i <= ses->maxfd && j < outlen; ++i)
    {
      const bool r = FD_ISSET (i, read);
      const bool w = FD_ISSET (i, write);
      if (r || w)
	{
	  out->rwflags = 0;
	  if (r)
	    out->rwflags |= EVENT_READ;
	  if (w)
	    out->rwflags |= EVENT_WRITE;
	  out->arg = ses->args[i];
	  msg (D_EVENT_WAIT, "SE_WAIT[%d,%d] rwflags=0x%04x arg=" ptr_format,
	       i, j, out->rwflags, (ptr_type)out->arg);
	  ++out;
	  ++j;
	}
    }
  return j;
}

static int
se_wait_fast (struct event_set *es, const struct timeval *tv, struct event_set_return *out, int outlen)
{
  struct se_set *ses = (struct se_set *) es;
  struct timeval tv_tmp = *tv;
  int stat;

  stat = select (ses->maxfd + 1, &ses->readfds, &ses->writefds, NULL, &tv_tmp);

  if (stat > 0)
    stat = se_wait_return (ses, &ses->readfds, &ses->writefds, out, outlen);

  return stat;
}

static int
se_wait_scalable (struct event_set *es, const struct timeval *tv, struct event_set_return *out, int outlen)
{
  struct se_set *ses = (struct se_set *) es;
  struct timeval tv_tmp = *tv;
  fd_set read = ses->readfds;
  fd_set write = ses->writefds;
  int stat;

  stat = select (ses->maxfd + 1, &read, &write, NULL, &tv_tmp);

  if (stat > 0)
    stat = se_wait_return (ses, &read, &write, out, outlen);

  return stat;
}

static struct event_set *
se_init (int *maxevents, unsigned int flags)
{
  const int maximum_fds = 256; // JYFIXME -- figure out the minimum on all OSes which OpenVPN supports
  struct se_set *ses;

  msg (D_EVENT_WAIT, "SE_INIT maxevents=%d flags=0x%08x", *maxevents, flags);

  ALLOC_OBJ_CLEAR (ses, struct se_set);

  /* set dispatch functions */
  ses->func.free = se_free;
  ses->func.reset = se_reset;
  ses->func.del = se_del;
  ses->func.ctl = se_ctl;
  ses->func.wait = se_wait_scalable;

  if (flags & EVENT_METHOD_FAST)
    {
      ses->fast = true;
      ses->func.wait = se_wait_fast;
    }

  /* Select needs to be passed this value + 1 */
  ses->maxfd = -1;

  /* Figure our event capacity */
  ASSERT (*maxevents > 0);
  *maxevents = min_int (*maxevents, maximum_fds);
  ses->capacity = *maxevents + 10;

  /* Allocate space for event_set_return void * args */
  ALLOC_ARRAY_CLEAR (ses->args, void *, ses->capacity);

  return (struct event_set *) ses;
}
#endif /* SELECT */

static struct event_set *
event_set_init_simple (int *maxevents, unsigned int flags)
{
  struct event_set *ret = NULL;
#ifdef WIN32
  ret = we_init (maxevents, flags);
#elif POLL && SELECT
  if (flags & EVENT_METHOD_US_TIMEOUT)
    ret = se_init (maxevents, flags); 
# ifdef SELECT_PREFERRED_OVER_POLL
   if (!ret)
     ret = se_init (maxevents, flags);
   if (!ret)
     ret = po_init (maxevents, flags);
# else
   if (!ret)
     ret = po_init (maxevents, flags);
   if (!ret)
     ret = se_init (maxevents, flags);
# endif
#elif POLL
  ret = po_init (maxevents, flags);
#elif SELECT
  ret = se_init (maxevents, flags);
#else
#error At least one of poll, select, or WSAWaitForMultipleEvents must be supported by the kernel
#endif
  ASSERT (ret);
  return ret;
}

static struct event_set *
event_set_init_scalable (int *maxevents, unsigned int flags)
{
  struct event_set *ret = NULL;
#if EPOLL
  ret = ep_init (maxevents, flags);
  if (!ret)
    {
      msg (M_WARN, "Note: sys_epoll API is unavailable, falling back to poll/select API");
      ret = event_set_init_simple (maxevents, flags);
    }
#else
  ret = event_set_init_simple (maxevents, flags);
#endif
  ASSERT (ret);
  return ret;
}

struct event_set *
event_set_init (int *maxevents, unsigned int flags)
{
  if (flags & EVENT_METHOD_FAST)
    return event_set_init_simple (maxevents, flags);
  else
    return event_set_init_scalable (maxevents, flags);
}