xref: /dflybsd-src/usr.sbin/route6d/misc/cksum.c (revision 86d7f5d305c6adaa56ff4582ece9859d73106103)
1*86d7f5d3SJohn Marino /*
2*86d7f5d3SJohn Marino  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3*86d7f5d3SJohn Marino  * All rights reserved.
4*86d7f5d3SJohn Marino  *
5*86d7f5d3SJohn Marino  * Redistribution and use in source and binary forms, with or without
6*86d7f5d3SJohn Marino  * modification, are permitted provided that the following conditions
7*86d7f5d3SJohn Marino  * are met:
8*86d7f5d3SJohn Marino  * 1. Redistributions of source code must retain the above copyright
9*86d7f5d3SJohn Marino  *    notice, this list of conditions and the following disclaimer.
10*86d7f5d3SJohn Marino  * 2. Redistributions in binary form must reproduce the above copyright
11*86d7f5d3SJohn Marino  *    notice, this list of conditions and the following disclaimer in the
12*86d7f5d3SJohn Marino  *    documentation and/or other materials provided with the distribution.
13*86d7f5d3SJohn Marino  * 3. Neither the name of the project nor the names of its contributors
14*86d7f5d3SJohn Marino  *    may be used to endorse or promote products derived from this software
15*86d7f5d3SJohn Marino  *    without specific prior written permission.
16*86d7f5d3SJohn Marino  *
17*86d7f5d3SJohn Marino  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18*86d7f5d3SJohn Marino  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19*86d7f5d3SJohn Marino  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20*86d7f5d3SJohn Marino  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21*86d7f5d3SJohn Marino  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22*86d7f5d3SJohn Marino  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23*86d7f5d3SJohn Marino  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24*86d7f5d3SJohn Marino  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25*86d7f5d3SJohn Marino  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26*86d7f5d3SJohn Marino  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27*86d7f5d3SJohn Marino  * SUCH DAMAGE.
28*86d7f5d3SJohn Marino  *
29*86d7f5d3SJohn Marino  * $FreeBSD: src/usr.sbin/route6d/misc/cksum.c,v 1.1 1999/12/28 02:37:10 shin Exp $
30*86d7f5d3SJohn Marino  * $DragonFly: src/usr.sbin/route6d/misc/cksum.c,v 1.3 2005/12/05 02:40:28 swildner Exp $
31*86d7f5d3SJohn Marino  */
32*86d7f5d3SJohn Marino 
33*86d7f5d3SJohn Marino #include <stdio.h>
34*86d7f5d3SJohn Marino 
35*86d7f5d3SJohn Marino unsigned short buf[BUFSIZ];
36*86d7f5d3SJohn Marino 
37*86d7f5d3SJohn Marino int
main(void)38*86d7f5d3SJohn Marino main(void)
39*86d7f5d3SJohn Marino {
40*86d7f5d3SJohn Marino 	int	i;
41*86d7f5d3SJohn Marino 	unsigned short *p = buf, *q = &buf[4];
42*86d7f5d3SJohn Marino 	unsigned long sum, sum2;
43*86d7f5d3SJohn Marino 
44*86d7f5d3SJohn Marino 	while (scanf("%x", &i) != EOF) {
45*86d7f5d3SJohn Marino 		*p++ = i; printf("%d ", i);
46*86d7f5d3SJohn Marino 	}
47*86d7f5d3SJohn Marino 	printf("\n");
48*86d7f5d3SJohn Marino 
49*86d7f5d3SJohn Marino 	sum = buf[2] + (buf[3] >> 8) & 0xff;
50*86d7f5d3SJohn Marino 	while (q != p)
51*86d7f5d3SJohn Marino 		sum += (*q++ & 0xffff);
52*86d7f5d3SJohn Marino 	sum2 = (sum & 0xffff) + (sum >> 16) & 0xffff;
53*86d7f5d3SJohn Marino 	printf("%x, %x\n", sum, sum2);
54*86d7f5d3SJohn Marino }
55