release/src-rt-6.x.4708/linux/linux-2.6.36/include/net/ip6_checksum.h

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Checksumming functions for IPv6
   7  *
   8  * Authors:     Jorge Cwik, <jorge@laser.satlink.net>
   9  *              Arnt Gulbrandsen, <agulbra@nvg.unit.no>
  10  *              Borrows very liberally from tcp.c and ip.c, see those
  11  *              files for more names.
  12  *
  13  *              This program is free software; you can redistribute it and/or
  14  *              modify it under the terms of the GNU General Public License
  15  *              as published by the Free Software Foundation; either version
  16  *              2 of the License, or (at your option) any later version.
  17  */
  18
  19 /*
  20  *      Fixes:
  21  *
  22  *      Ralf Baechle                    :       generic ipv6 checksum
  23  *      <ralf@waldorf-gmbh.de>
  24  */
  25
  26 #ifndef _CHECKSUM_IPV6_H
  27 #define _CHECKSUM_IPV6_H
  28
  29 #include <asm/types.h>
  30 #include <asm/byteorder.h>
  31 #include <net/ip.h>
  32 #include <asm/checksum.h>
  33 #include <linux/in6.h>
  34
  35 #ifndef _HAVE_ARCH_IPV6_CSUM
  36
  37 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
  38                                           const struct in6_addr *daddr,
  39                                           __u32 len, unsigned short proto,
  40                                           __wsum csum)
  41 {
  42
  43         int carry;
  44         __u32 ulen;
  45         __u32 uproto;
  46         __u32 sum = (__force u32)csum;
  47
  48         sum += (__force u32)saddr->s6_addr32[0];
  49         carry = (sum < (__force u32)saddr->s6_addr32[0]);
  50         sum += carry;
  51
  52         sum += (__force u32)saddr->s6_addr32[1];
  53         carry = (sum < (__force u32)saddr->s6_addr32[1]);
  54         sum += carry;
  55
  56         sum += (__force u32)saddr->s6_addr32[2];
  57         carry = (sum < (__force u32)saddr->s6_addr32[2]);
  58         sum += carry;
  59
  60         sum += (__force u32)saddr->s6_addr32[3];
  61         carry = (sum < (__force u32)saddr->s6_addr32[3]);
  62         sum += carry;
  63
  64         sum += (__force u32)daddr->s6_addr32[0];
  65         carry = (sum < (__force u32)daddr->s6_addr32[0]);
  66         sum += carry;
  67
  68         sum += (__force u32)daddr->s6_addr32[1];
  69         carry = (sum < (__force u32)daddr->s6_addr32[1]);
  70         sum += carry;
  71
  72         sum += (__force u32)daddr->s6_addr32[2];
  73         carry = (sum < (__force u32)daddr->s6_addr32[2]);
  74         sum += carry;
  75
  76         sum += (__force u32)daddr->s6_addr32[3];
  77         carry = (sum < (__force u32)daddr->s6_addr32[3]);
  78         sum += carry;
  79
  80         ulen = (__force u32)htonl((__u32) len);
  81         sum += ulen;
  82         carry = (sum < ulen);
  83         sum += carry;
  84
  85         uproto = (__force u32)htonl(proto);
  86         sum += uproto;
  87         carry = (sum < uproto);
  88         sum += carry;
  89
  90         return csum_fold((__force __wsum)sum);
  91 }
  92
  93 #endif
  94 #endif