1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate * CDDL HEADER START
3*0Sstevel@tonic-gate *
4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance
7*0Sstevel@tonic-gate * with the License.
8*0Sstevel@tonic-gate *
9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate * and limitations under the License.
13*0Sstevel@tonic-gate *
14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate *
20*0Sstevel@tonic-gate * CDDL HEADER END
21*0Sstevel@tonic-gate */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate * Copyright (c) 1996-2001 by Sun Microsystems, Inc.
24*0Sstevel@tonic-gate * All rights reserved.
25*0Sstevel@tonic-gate */
26*0Sstevel@tonic-gate
27*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI"
28*0Sstevel@tonic-gate
29*0Sstevel@tonic-gate #include <sys/types.h>
30*0Sstevel@tonic-gate #include "v4_sum_impl.h"
31*0Sstevel@tonic-gate
32*0Sstevel@tonic-gate /*
33*0Sstevel@tonic-gate * Compute one's complement checksum for IP packet headers.
34*0Sstevel@tonic-gate */
35*0Sstevel@tonic-gate uint16_t
ipv4cksum(uint16_t * cp,uint16_t count)36*0Sstevel@tonic-gate ipv4cksum(uint16_t *cp, uint16_t count)
37*0Sstevel@tonic-gate {
38*0Sstevel@tonic-gate uint_t sum = 0;
39*0Sstevel@tonic-gate uint_t oneword = BIT_WRAP;
40*0Sstevel@tonic-gate
41*0Sstevel@tonic-gate if (count == 0)
42*0Sstevel@tonic-gate return (0);
43*0Sstevel@tonic-gate
44*0Sstevel@tonic-gate count >>= 1;
45*0Sstevel@tonic-gate while (count--) {
46*0Sstevel@tonic-gate sum += (uint_t)*cp++;
47*0Sstevel@tonic-gate if (sum >= oneword) { /* Wrap carries into low bit */
48*0Sstevel@tonic-gate sum -= oneword;
49*0Sstevel@tonic-gate sum++;
50*0Sstevel@tonic-gate }
51*0Sstevel@tonic-gate }
52*0Sstevel@tonic-gate return ((uint16_t)~sum);
53*0Sstevel@tonic-gate }
54