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Revision 1.1, Mon Oct 8 10:44:50 2007 UTC (16 years, 7 months ago) by norby
Branch: MAIN
CVS Tags: OPENBSD_7_5_BASE, OPENBSD_7_5, OPENBSD_7_4_BASE, OPENBSD_7_4, OPENBSD_7_3_BASE, OPENBSD_7_3, OPENBSD_7_2_BASE, OPENBSD_7_2, OPENBSD_7_1_BASE, OPENBSD_7_1, OPENBSD_7_0_BASE, OPENBSD_7_0, OPENBSD_6_9_BASE, OPENBSD_6_9, OPENBSD_6_8_BASE, OPENBSD_6_8, OPENBSD_6_7_BASE, OPENBSD_6_7, OPENBSD_6_6_BASE, OPENBSD_6_6, OPENBSD_6_5_BASE, OPENBSD_6_5, OPENBSD_6_4_BASE, OPENBSD_6_4, OPENBSD_6_3_BASE, OPENBSD_6_3, OPENBSD_6_2_BASE, OPENBSD_6_2, OPENBSD_6_1_BASE, OPENBSD_6_1, OPENBSD_6_0_BASE, OPENBSD_6_0, OPENBSD_5_9_BASE, OPENBSD_5_9, OPENBSD_5_8_BASE, OPENBSD_5_8, OPENBSD_5_7_BASE, OPENBSD_5_7, OPENBSD_5_6_BASE, OPENBSD_5_6, OPENBSD_5_5_BASE, OPENBSD_5_5, OPENBSD_5_4_BASE, OPENBSD_5_4, OPENBSD_5_3_BASE, OPENBSD_5_3, OPENBSD_5_2_BASE, OPENBSD_5_2, OPENBSD_5_1_BASE, OPENBSD_5_1, OPENBSD_5_0_BASE, OPENBSD_5_0, OPENBSD_4_9_BASE, OPENBSD_4_9, OPENBSD_4_8_BASE, OPENBSD_4_8, OPENBSD_4_7_BASE, OPENBSD_4_7, OPENBSD_4_6_BASE, OPENBSD_4_6, OPENBSD_4_5_BASE, OPENBSD_4_5, OPENBSD_4_4_BASE, OPENBSD_4_4, OPENBSD_4_3_BASE, OPENBSD_4_3, HEAD 

Welcome ospf6d

The new ospf6d daemon will support OSPFv3, basically OSPF for IPv6 networks.

It is heavily based on ospfd(8), it is more or less a copy and paste of it.
Currently some unneeded stuff has been removed and the trasition from
IPv4 to IPv6 has begun.

ospf6d is not very usefull at the moment, it is being imported to allow more
people to work on it concurrently.

Not yet connected to the builds.

ok claudio@ dlg@

/*	$OpenBSD: iso_cksum.c,v 1.1 2007/10/08 10:44:50 norby Exp $ */

/*
 * Copyright (c) 2005 Claudio Jeker <claudio@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>

#include "ospf6d.h"

/* implementation of Fletcher Checksum -- see RFC 1008 for more info */

/* pos needs to be 0 for verify and 2 <= pos < len for calculation */
u_int16_t
iso_cksum(void *buf, u_int16_t len, u_int16_t pos)
{
	u_int8_t	*p = buf;
	int		 c0 = 0, c1 = 0, x;	/* counters */
	u_int16_t	 sop;

	sop = len - pos - 1;	/* pos is an offset (pos 2 is 3rd element) */
	p += 2;			/* jump over age field */
	len -= 2;
	while (len--) {
		c0 += *p++;
		c1 += c0;
		if ((len & 0xfff) == 0) {
			/* overflow protection */
			c0 %= 255;
			c1 %= 255;
		}
	}

	if (pos) {
		x = ((sop * c0 - c1)) % 255;
		if (x <= 0)
			x += 255;
		c1 = 510 - c0 - x;
		if (c1 > 255)
			c1 -= 255;
		c0 = x;
	}

	return (c0 << 8 | c1);
}