core/ipv4/ip_addr.c

0001 /**
0002  * @file
0003  * This is the IPv4 address tools implementation.
0004  *
0005  */
0006
0007 /*
0008  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
0009  * All rights reserved.
0010  *
0011  * Redistribution and use in source and binary forms, with or without modification,
0012  * are permitted provided that the following conditions are met:
0013  *
0014  * 1. Redistributions of source code must retain the above copyright notice,
0015  *    this list of conditions and the following disclaimer.
0016  * 2. Redistributions in binary form must reproduce the above copyright notice,
0017  *    this list of conditions and the following disclaimer in the documentation
0018  *    and/or other materials provided with the distribution.
0019  * 3. The name of the author may not be used to endorse or promote products
0020  *    derived from this software without specific prior written permission.
0021  *
0022  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
0023  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
0024  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
0025  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
0026  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
0027  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0028  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0029  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
0030  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
0031  * OF SUCH DAMAGE.
0032  *
0033  * This file is part of the lwIP TCP/IP stack.
0034  *
0035  * Author: Adam Dunkels <adam@sics.se>
0036  *
0037  */
0038
0039 #include "lwip/opt.h"
0040 #include "lwip/ip_addr.h"
0041 #include "lwip/inet.h"
0042 #include "lwip/netif.h"
0043
0044 #define IP_ADDR_ANY_VALUE 0x00000000UL
0045 #define IP_ADDR_BROADCAST_VALUE 0xffffffffUL
0046
0047 /* used by IP_ADDR_ANY and IP_ADDR_BROADCAST in ip_addr.h */
0048 const struct ip_addr ip_addr_any = { IP_ADDR_ANY_VALUE };
0049 const struct ip_addr ip_addr_broadcast = { IP_ADDR_BROADCAST_VALUE };
0050
0051 /**
0052  * Determine if an address is a broadcast address on a network interface
0053  *
0054  * @param addr address to be checked
0055  * @param netif the network interface against which the address is checked
0056  * @return returns non-zero if the address is a broadcast address
0057  */
0058 u8_t ip_addr_isbroadcast(struct ip_addr *addr, struct netif *netif)
0059 {
0060   u32_t addr2test;
0061
0062   addr2test = addr->addr;
0063   /* all ones (broadcast) or all zeroes (old skool broadcast) */
0064   if ((~addr2test == IP_ADDR_ANY_VALUE) ||
0065       (addr2test == IP_ADDR_ANY_VALUE))
0066     return 1;
0067   /* no broadcast support on this network interface? */
0068   else if ((netif->flags & NETIF_FLAG_BROADCAST) == 0)
0069     /* the given address cannot be a broadcast address
0070      * nor can we check against any broadcast addresses */
0071     return 0;
0072   /* address matches network interface address exactly? => no broadcast */
0073   else if (addr2test == netif->ip_addr.addr)
0074     return 0;
0075   /*  on the same (sub) network... */
0076   else if (ip_addr_netcmp(addr, &(netif->ip_addr), &(netif->netmask))
0077          /* ...and host identifier bits are all ones? =>... */
0078           && ((addr2test & ~netif->netmask.addr) ==
0079            (IP_ADDR_BROADCAST_VALUE & ~netif->netmask.addr)))
0080     /* => network broadcast address */
0081     return 1;
0082   else
0083     return 0;
0084 }