LXR linux/include/asm-m68k/checksum.h

   1#ifndef _M68K_CHECKSUM_H
   2#define _M68K_CHECKSUM_H
   3
   4#include <linux/in6.h>
   5
   6/*
   7 * computes the checksum of a memory block at buff, length len,
   8 * and adds in "sum" (32-bit)
   9 *
  10 * returns a 32-bit number suitable for feeding into itself
  11 * or csum_tcpudp_magic
  12 *
  13 * this function must be called with even lengths, except
  14 * for the last fragment, which may be odd
  15 *
  16 * it's best to have buff aligned on a 32-bit boundary
  17 */
  18__wsum csum_partial(const void *buff, int len, __wsum sum);
  19
  20/*
  21 * the same as csum_partial, but copies from src while it
  22 * checksums
  23 *
  24 * here even more important to align src and dst on a 32-bit (or even
  25 * better 64-bit) boundary
  26 */
  27
  28extern __wsum csum_partial_copy_from_user(const void __user *src,
  29                                                void *dst,
  30                                                int len, __wsum sum,
  31                                                int *csum_err);
  32
  33extern __wsum csum_partial_copy_nocheck(const void *src,
  34                                              void *dst, int len,
  35                                              __wsum sum);
  36
  37/*
  38 *      This is a version of ip_compute_csum() optimized for IP headers,
  39 *      which always checksum on 4 octet boundaries.
  40 *
  41 */
  42static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  43{
  44        unsigned int sum = 0;
  45        unsigned long tmp;
  46
  47        __asm__ ("subqw #1,%2\n"
  48                 "1:\t"
  49                 "movel %1@+,%3\n\t"
  50                 "addxl %3,%0\n\t"
  51                 "dbra  %2,1b\n\t"
  52                 "movel %0,%3\n\t"
  53                 "swap  %3\n\t"
  54                 "addxw %3,%0\n\t"
  55                 "clrw  %3\n\t"
  56                 "addxw %3,%0\n\t"
  57                 : "=d" (sum), "=&a" (iph), "=&d" (ihl), "=&d" (tmp)
  58                 : "0" (sum), "1" (iph), "2" (ihl)
  59                 : "memory");
  60        return (__force __sum16)~sum;
  61}
  62
  63/*
  64 *      Fold a partial checksum
  65 */
  66
  67static inline __sum16 csum_fold(__wsum sum)
  68{
  69        unsigned int tmp = (__force u32)sum;
  70        __asm__("swap %1\n\t"
  71                "addw %1, %0\n\t"
  72                "clrw %1\n\t"
  73                "addxw %1, %0"
  74                : "=&d" (sum), "=&d" (tmp)
  75                : "0" (sum), "1" (tmp));
  76        return (__force __sum16)~sum;
  77}
  78
  79
  80static inline __wsum
  81csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
  82                  unsigned short proto, __wsum sum)
  83{
  84        __asm__ ("addl  %2,%0\n\t"
  85                 "addxl %3,%0\n\t"
  86                 "addxl %4,%0\n\t"
  87                 "clrl %1\n\t"
  88                 "addxl %1,%0"
  89                 : "=&d" (sum), "=d" (saddr)
  90                 : "g" (daddr), "1" (saddr), "d" (len + proto),
  91                   "0" (sum));
  92        return sum;
  93}
  94
  95
  96/*
  97 * computes the checksum of the TCP/UDP pseudo-header
  98 * returns a 16-bit checksum, already complemented
  99 */
 100static inline __sum16
 101csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
 102                  unsigned short proto, __wsum sum)
 103{
 104        return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 105}
 106
 107/*
 108 * this routine is used for miscellaneous IP-like checksums, mainly
 109 * in icmp.c
 110 */
 111
 112static inline __sum16 ip_compute_csum(const void *buff, int len)
 113{
 114        return csum_fold (csum_partial(buff, len, 0));
 115}
 116
 117#define _HAVE_ARCH_IPV6_CSUM
 118static __inline__ __sum16
 119csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
 120                __u32 len, unsigned short proto, __wsum sum)
 121{
 122        register unsigned long tmp;
 123        __asm__("addl %2@,%0\n\t"
 124                "movel %2@(4),%1\n\t"
 125                "addxl %1,%0\n\t"
 126                "movel %2@(8),%1\n\t"
 127                "addxl %1,%0\n\t"
 128                "movel %2@(12),%1\n\t"
 129                "addxl %1,%0\n\t"
 130                "movel %3@,%1\n\t"
 131                "addxl %1,%0\n\t"
 132                "movel %3@(4),%1\n\t"
 133                "addxl %1,%0\n\t"
 134                "movel %3@(8),%1\n\t"
 135                "addxl %1,%0\n\t"
 136                "movel %3@(12),%1\n\t"
 137                "addxl %1,%0\n\t"
 138                "addxl %4,%0\n\t"
 139                "clrl %1\n\t"
 140                "addxl %1,%0"
 141                : "=&d" (sum), "=&d" (tmp)
 142                : "a" (saddr), "a" (daddr), "d" (len + proto),
 143                  "0" (sum));
 144
 145        return csum_fold(sum);
 146}
 147
 148#endif /* _M68K_CHECKSUM_H */
 149