ip6_checksum.h

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/*
 * 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, <[email protected]>
 *      Arnt Gulbrandsen, <[email protected]>
 *      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
 *  <[email protected]>
 */

#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