root/arch/x86/um/asm/checksum_32.h

INCLUDED FROM

DEFINITIONS

1. ip_compute_csum
2. csum_ipv6_magic
3. csum_and_copy_to_user

   1 /*
   2  * Licensed under the GPL
   3  */
   4 
   5 #ifndef __UM_SYSDEP_CHECKSUM_H
   6 #define __UM_SYSDEP_CHECKSUM_H
   7 
   8 static inline __sum16 ip_compute_csum(const void *buff, int len)
   9 {
  10     return csum_fold (csum_partial(buff, len, 0));
  11 }
  12 
  13 #define _HAVE_ARCH_IPV6_CSUM
  14 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
  15                                           const struct in6_addr *daddr,
  16                                           __u32 len, __u8 proto,
  17                                           __wsum sum)
  18 {
  19         __asm__(
  20                 "addl 0(%1), %0         ;\n"
  21                 "adcl 4(%1), %0         ;\n"
  22                 "adcl 8(%1), %0         ;\n"
  23                 "adcl 12(%1), %0        ;\n"
  24                 "adcl 0(%2), %0         ;\n"
  25                 "adcl 4(%2), %0         ;\n"
  26                 "adcl 8(%2), %0         ;\n"
  27                 "adcl 12(%2), %0        ;\n"
  28                 "adcl %3, %0            ;\n"
  29                 "adcl %4, %0            ;\n"
  30                 "adcl $0, %0            ;\n"
  31                 : "=&r" (sum)
  32                 : "r" (saddr), "r" (daddr),
  33                   "r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
  34 
  35         return csum_fold(sum);
  36 }
  37 
  38 /*
  39  *      Copy and checksum to user
  40  */
  41 #define HAVE_CSUM_COPY_USER
  42 static __inline__ __wsum csum_and_copy_to_user(const void *src,
  43                                                      void __user *dst,
  44                                                      int len, __wsum sum, int *err_ptr)
  45 {
  46         if (access_ok(dst, len)) {
  47                 if (copy_to_user(dst, src, len)) {
  48                         *err_ptr = -EFAULT;
  49                         return (__force __wsum)-1;
  50                 }
  51 
  52                 return csum_partial(src, len, sum);
  53         }
  54 
  55         if (len)
  56                 *err_ptr = -EFAULT;
  57 
  58         return (__force __wsum)-1; /* invalid checksum */
  59 }
  60 
  61 #endif