nuttx/net/neighbor/neighbor_periodic.c

/****************************************************************************
 * net/neighbor/neighbor_periodic.c
 *
 *   Copyright (C) 2007-2009, 2015 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * A leverage of logic from uIP which also has a BSD style license
 *
 *   Copyright (c) 2006, Swedish Institute of Computer Science.  All rights
 *     reserved.
 *   Author: Adam Dunkels <adam@sics.se>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>
#include <nuttx/clock.h>

#include "neighbor/neighbor.h"

/****************************************************************************
 * Public Functions
 ****************************************************************************/

#define USEC_PER_HSEC    500000
#define TICK_PER_HSEC    (USEC_PER_HSEC / USEC_PER_TICK)   /* Truncates! */
#define TICK2HSEC(tick)  (((tick)+(TICK_PER_HSEC/2))/TICK_PER_HSEC) /* Rounds */

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: neighbor_periodic
 *
 * Description:
 *   Called from the timer poll logic in order to perform agin operations on
 *   entries in the Neighbor Table
 *
 * Input Parameters:
 *   None
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

void neighbor_periodic(void)
{
  uint32_t now;
  uint32_t ticks;
  uint32_t hsecs;
  int i;

  /* Get the elapsed time in units of half seconds */

  now   = clock_systimer();
  ticks = now - g_neighbor_polltime;
  hsecs = TICK2HSEC(ticks);

  /* Reset the time of the last poll */

  g_neighbor_polltime = now;

  /* Add the elapsed half seconds from each activate entry in the
   * Neighbor table.
   */

  for (i = 0; i < CONFIG_NET_IPv6_NCONF_ENTRIES; ++i)
    {
      uint32_t newtime = g_neighbors[i].ne_time + hsecs;
      if (newtime > NEIGHBOR_MAXTIME)
        {
          newtime = NEIGHBOR_MAXTIME;
        }

      g_neighbors[i].ne_time = newtime;
    }
}