lib/lwip/src/core/ipv4/ip_addr.c

/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved. 
 * 
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * This file is part of the lwIP TCP/IP stack.
 * 
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

#include "lwip/ip_addr.h"
#include "lwip/inet.h"
#include "lwip/netif.h"

/* used by IP_ADDR_ANY and IP_ADDR_BROADCAST in ip_addr.h */
const struct ip_addr ip_addr_any = { 0x00000000UL };
const struct ip_addr ip_addr_broadcast = { 0xffffffffUL };

/* Determine if an address is a broadcast address on a network interface 
 * 
 * @param addr address to be checked
 * @param netif the network interface against which the address is checked
 * @return returns non-zero if the address is a broadcast address
 *
 */

u8_t ip_addr_isbroadcast(struct ip_addr *addr, struct netif *netif)
{
  /* all ones (broadcast) or all zeroes (old skool broadcast) */
  if ((addr->addr == ip_addr_broadcast.addr) ||
      (addr->addr == ip_addr_any.addr))
    return 1;
  /* no broadcast support on this network interface? */
  else if ((netif->flags & NETIF_FLAG_BROADCAST) == 0)
    /* the given address cannot be a broadcast address
     * nor can we check against any broadcast addresses */
    return 0;
  /* address matches network interface address exactly? => no broadcast */
  else if (addr->addr == netif->ip_addr.addr)
    return 0;
  /*  on the same (sub) network... */
  else if (ip_addr_netcmp(addr, &(netif->ip_addr), &(netif->netmask))
         /* ...and host identifier bits are all ones? =>... */
          && ((addr->addr & ~netif->netmask.addr) ==
           (ip_addr_broadcast.addr & ~netif->netmask.addr)))
    /* => network broadcast address */
    return 1;
  else
    return 0;
}