nuttx/net/uip/uip_igmpsend.c

/****************************************************************************
 * net/uip/uip_igmpsend.c
 *
 *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
 *
 * 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 NuttX 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 COPYRIGHT HOLDERS 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
 * COPYRIGHT OWNER 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 <debug.h>

#include <net/uip/uipopt.h>
#include <net/uip/uip.h>
#include <net/uip/uip-arch.h>
#include <net/uip/uip-igmp.h>

#include "uip_internal.h"

#ifdef CONFIG_NET_IGMP

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

#define RASIZE      (8)
#define ROUTERALERT ((uint16_t*)&dev->d_buf[UIP_LLH_LEN])
#define IGMPBUF     ((struct uip_igmphdr_s *)&dev->d_buf[UIP_LLH_LEN + RASIZE])
#define IGMPPAYLOAD (&dev->d_buf[UIP_LLH_LEN + RASIZE + UIP_IPH_LEN])

/****************************************************************************
 * Public Variables
 ****************************************************************************/

/****************************************************************************
 * Private Variables
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/
 
static uint16_t uip_igmpchksum(FAR uint8_t *buffer, int buflen)
{
  uint16_t sum = uip_chksum((FAR uint16_t*)buffer, buflen);
  return sum ? sum : 0xffff;
}

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

/****************************************************************************
 * Name: uip_igmpsend
 *
 * Description:
 *   Sends an IGMP IP packet on a network interface. This function constructs
 *   the IP header and calculates the IP header checksum.
 *
 * Parameters:
 *   dev       - The device driver structure to use in the send operation.
 *   group     - Describes the multicast group member and identifies the message
 *                to be sent.
 *   destipaddr - The IP address of the recipient of the message
 *
 * Return:
 *   None
 *
 * Assumptions:
 *   Called from the interrupt level or with interrupts disabled.
 *
 ****************************************************************************/

void uip_igmpsend(FAR struct uip_driver_s *dev, FAR struct igmp_group_s *group,
                  FAR uip_ipaddr_t *destipaddr)
{
  /* The total length to send is the size of the IP and IGMP headers and 8
   * bytes for the ROUTER ALERT (and, eventually, the ethernet header)
   */

  dev->d_len           = UIP_IPIGMPH_LEN + RASIZE;

  /* The total size of the data is the size of the IGMP header */

  dev->d_sndlen        = UIP_IGMPH_LEN;

  /* Add the router alert option */

  ROUTERALERT[0]       = HTONS(0x9404);
  ROUTERALERT[1]       = 0;

  /* Initialize the IPv4 header */

  IGMPBUF->vhl         = 0x45;
  IGMPBUF->tos         = 0;
  IGMPBUF->len[0]      = (dev->d_len >> 8);
  IGMPBUF->len[1]      = (dev->d_len & 0xff);
  ++g_ipid;
  IGMPBUF->ipid[0]     = g_ipid >> 8;
  IGMPBUF->ipid[1]     = g_ipid & 0xff;
  IGMPBUF->ipoffset[0] = UIP_TCPFLAG_DONTFRAG >> 8;
  IGMPBUF->ipoffset[1] = UIP_TCPFLAG_DONTFRAG & 0xff;
  IGMPBUF->ttl         = IGMP_TTL;
  IGMPBUF->proto       = UIP_PROTO_IGMP;

  uiphdr_ipaddr_copy(IGMPBUF->srcipaddr, &dev->d_ipaddr);
  uiphdr_ipaddr_copy(IGMPBUF->destipaddr, destipaddr);

  /* Calculate IP checksum. */

  IGMPBUF->ipchksum    = 0;
  IGMPBUF->ipchksum    = ~uip_igmpchksum((FAR uint8_t *)ROUTERALERT, UIP_IPH_LEN + RASIZE);

  /* Set up the IGMP message */

  IGMPBUF->type    = group->msgid;
  IGMPBUF->maxresp = 0;
  uiphdr_ipaddr_copy(IGMPBUF->grpaddr, &group->grpaddr);

  /* Calculate the IGMP checksum. */

  IGMPBUF->chksum  = 0;
  IGMPBUF->chksum  = ~uip_igmpchksum(IGMPPAYLOAD, UIP_IPIGMPH_LEN);

  IGMP_STATINCR(uip_stats.igmp.poll_send);
  IGMP_STATINCR(uip_stats.ip.sent);

  nllvdbg("Outgoing IGMP packet length: %d (%d)\n",
          dev->d_len, (IGMPBUF->len[0] << 8) | IGMPBUF->len[1]);

}

#endif /* CONFIG_NET_IGMP */