/* inet.c
Subroutines to manipulate internet addresses in a safely portable
way... */
/*
* Copyright (c) 1996 The Internet Software Consortium. 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. Neither the name of The Internet Software Consortium 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 INTERNET SOFTWARE CONSORTIUM 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 INTERNET SOFTWARE CONSORTIUM 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.
*
* This software has been written for the Internet Software Consortium
* by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
* Enterprises. To learn more about the Internet Software Consortium,
* see ``http://www.vix.com/isc''. To learn more about Vixie
* Enterprises, see ``http://www.vix.com''.
*/
#ifndef lint
static char copyright[] =
"$Id: inet.c,v 1.5.2.2 1999/04/24 16:48:10 mellon Exp $ Copyright (c) 1995, 1996, 1998, 1999 The Internet Software Consortium. All rights reserved.\n";
#endif /* not lint */
#include "dhcpd.h"
/* Return just the network number of an internet address... */
struct iaddr subnet_number (addr, mask)
struct iaddr addr;
struct iaddr mask;
{
int i;
struct iaddr rv;
rv.len = 0;
/* Both addresses must have the same length... */
if (addr.len != mask.len)
return rv;
rv.len = addr.len;
for (i = 0; i < rv.len; i++)
rv.iabuf [i] = addr.iabuf [i] & mask.iabuf [i];
return rv;
}
/* Combine a network number and a integer to produce an internet address.
This won't work for subnets with more than 32 bits of host address, but
maybe this isn't a problem. */
struct iaddr ip_addr (subnet, mask, host_address)
struct iaddr subnet;
struct iaddr mask;
u_int32_t host_address;
{
int i, j, k;
u_int32_t swaddr;
struct iaddr rv;
unsigned char habuf [sizeof swaddr];
swaddr = htonl (host_address);
memcpy (habuf, &swaddr, sizeof swaddr);
/* Combine the subnet address and the host address. If
the host address is bigger than can fit in the subnet,
return a zero-length iaddr structure. */
rv = subnet;
j = rv.len - sizeof habuf;
for (i = sizeof habuf - 1; i >= 0; i--) {
if (mask.iabuf [i + j]) {
if (habuf [i] > (mask.iabuf [i + j] ^ 0xFF)) {
rv.len = 0;
return rv;
}
for (k = i - 1; k >= 0; k--) {
if (habuf [k]) {
rv.len = 0;
return rv;
}
}
rv.iabuf [i + j] |= habuf [i];
break;
} else
rv.iabuf [i + j] = habuf [i];
}
return rv;
}
/* Given a subnet number and netmask, return the address on that subnet
for which the host portion of the address is all ones (the standard
broadcast address). */
struct iaddr broadcast_addr (subnet, mask)
struct iaddr subnet;
struct iaddr mask;
{
int i;
struct iaddr rv;
if (subnet.len != mask.len) {
rv.len = 0;
return rv;
}
for (i = 0; i < subnet.len; i++) {
rv.iabuf [i] = subnet.iabuf [i] | (~mask.iabuf [i] & 255);
}
rv.len = subnet.len;
return rv;
}
u_int32_t host_addr (addr, mask)
struct iaddr addr;
struct iaddr mask;
{
int i;
u_int32_t swaddr;
struct iaddr rv;
rv.len = 0;
/* Mask out the network bits... */
rv.len = addr.len;
for (i = 0; i < rv.len; i++)
rv.iabuf [i] = addr.iabuf [i] & ~mask.iabuf [i];
/* Copy out up to 32 bits... */
memcpy (&swaddr, &rv.iabuf [rv.len - sizeof swaddr], sizeof swaddr);
/* Swap it and return it. */
return ntohl (swaddr);
}
int addr_eq (addr1, addr2)
struct iaddr addr1, addr2;
{
if (addr1.len != addr2.len)
return 0;
return memcmp (addr1.iabuf, addr2.iabuf, addr1.len) == 0;
}
char *piaddr (addr)
struct iaddr addr;
{
static char pbuf [4 * 16];
char *s = pbuf;
int i;
if (addr.len == 0) {
strcpy (s, "<null address>");
}
for (i = 0; i < addr.len; i++) {
sprintf (s, "%s%d", i ? "." : "", addr.iabuf [i]);
s += strlen (s);
}
return pbuf;
}
