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/* $OpenBSD: inet.c,v 1.4 2004/02/07 13:26:35 henning Exp $ */
/*
* 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''.
*/
#include "dhcpd.h"
/*
* Return just the network number of an internet address...
*/
struct iaddr
subnet_number(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(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(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(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(struct iaddr addr1, struct iaddr addr2)
{
if (addr1.len != addr2.len)
return (0);
return (memcmp(addr1.iabuf, addr2.iabuf, addr1.len) == 0);
}
char *piaddr(struct iaddr addr)
{
static char pbuf[32];
char *s;
struct in_addr a;
memcpy(&a, &(addr.iabuf), sizeof(struct in_addr));
if (addr.len == 0)
strlcpy(pbuf, "<null address>", sizeof(pbuf));
else {
s = inet_ntoa(a);
if (s != NULL)
strlcpy(pbuf, s, sizeof(pbuf));
else
strlcpy(pbuf, "<invalid address>", sizeof(pbuf));
}
return (pbuf);
}
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