www.pudn.com > TCPmodbushy.rar > 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  
 * 
 */ 
 
#include "o:/IPV4/lwip/ip_addr.h" 
#include "o:/IPV4/lwip/inet.h" 
#include "o:/lwip/netif.h" 
 
/* used by IP_ADDR_ANY and IP_ADDR_BROADCAST in ip_addr.h */ 
const struct ip_addr xdata ip_addr_any = { 0x00000000UL }; 
const struct ip_addr xdata 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 xdata *addr) 
{ 
  /* all ones (broadcast) or all zeroes (old skool broadcast) */ 
  if ((addr->addr == ip_addr_broadcast.addr) || 
      (addr->addr == ip_addr_any.addr)) 
    return 1; 
  /* 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; 
}