/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 1996-2001 by Sun Microsystems, Inc.
* All rights reserved.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <sys/types.h>
#include "v4_sum_impl.h"
/*
* Compute one's complement checksum for IP packet headers.
*/
uint16_t
ipv4cksum(uint16_t *cp, uint16_t count)
{
uint_t sum = 0;
uint_t oneword = BIT_WRAP;
if (count == 0)
return (0);
count >>= 1;
while (count--) {
sum += (uint_t)*cp++;
if (sum >= oneword) { /* Wrap carries into low bit */
sum -= oneword;
sum++;
}
}
return ((uint16_t)~sum);
}