root/include/net/ip6_checksum.h

INCLUDED FROM

DEFINITIONS

1. csum_ipv6_magic

/*
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              Checksumming functions for IPv6
 *
 * Authors:     Jorge Cwik, <jorge@laser.satlink.net>
 *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
 *              Borrows very liberally from tcp.c and ip.c, see those
 *              files for more names.
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 */

/*
 *      Fixes:
 *
 *      Ralf Baechle                    :       generic ipv6 checksum
 *      <ralf@waldorf-gmbh.de>
 */

#ifndef _CHECKSUM_IPV6_H
#define _CHECKSUM_IPV6_H

#include <asm/types.h>
#include <asm/byteorder.h>
#include <net/ip.h>
#include <asm/checksum.h>
#include <linux/in6.h>

#ifndef _HAVE_ARCH_IPV6_CSUM

static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
                                          const struct in6_addr *daddr,
                                          __u32 len, unsigned short proto,
                                          __wsum csum)
{

        int carry;
        __u32 ulen;
        __u32 uproto;
        __u32 sum = (__force u32)csum;

        sum += (__force u32)saddr->s6_addr32[0];
        carry = (sum < (__force u32)saddr->s6_addr32[0]);
        sum += carry;

        sum += (__force u32)saddr->s6_addr32[1];
        carry = (sum < (__force u32)saddr->s6_addr32[1]);
        sum += carry;

        sum += (__force u32)saddr->s6_addr32[2];
        carry = (sum < (__force u32)saddr->s6_addr32[2]);
        sum += carry;

        sum += (__force u32)saddr->s6_addr32[3];
        carry = (sum < (__force u32)saddr->s6_addr32[3]);
        sum += carry;

        sum += (__force u32)daddr->s6_addr32[0];
        carry = (sum < (__force u32)daddr->s6_addr32[0]);
        sum += carry;

        sum += (__force u32)daddr->s6_addr32[1];
        carry = (sum < (__force u32)daddr->s6_addr32[1]);
        sum += carry;

        sum += (__force u32)daddr->s6_addr32[2];
        carry = (sum < (__force u32)daddr->s6_addr32[2]);
        sum += carry;

        sum += (__force u32)daddr->s6_addr32[3];
        carry = (sum < (__force u32)daddr->s6_addr32[3]);
        sum += carry;

        ulen = (__force u32)htonl((__u32) len);
        sum += ulen;
        carry = (sum < ulen);
        sum += carry;

        uproto = (__force u32)htonl(proto);
        sum += uproto;
        carry = (sum < uproto);
        sum += carry;

        return csum_fold((__force __wsum)sum);
}

#endif
#endif