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 unsigned int csum_partial(const unsigned char * buff, int len, unsigned int 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
  28 extern unsigned int csum_partial_copy_from_user(const char *src, char *dst,
  29                                                 int len, int sum, int *csum_err);
  30
  31 extern unsigned int csum_partial_copy_nocheck(const char *src, char *dst,
  32                                               int len, int sum);
  33
  34 /*
  35  *      This is a version of ip_compute_csum() optimized for IP headers,
  36  *      which always checksum on 4 octet boundaries.
  37  *
  38  */
  39 static inline unsigned short
  40 ip_fast_csum(unsigned char *iph, unsigned int ihl)
  41 {
  42         unsigned int sum = 0;
  43
  44         __asm__ ("subqw #1,%2\n"
  45                  "1:\t"
  46                  "movel %1@+,%/d0\n\t"
  47                  "addxl %/d0,%0\n\t"
  48                  "dbra  %2,1b\n\t"
  49                  "movel %0,%/d0\n\t"
  50                  "swap  %/d0\n\t"
  51                  "addxw %/d0,%0\n\t"
  52                  "clrw  %/d0\n\t"
  53                  "addxw %/d0,%0\n\t"
  54                  : "=d" (sum), "=a" (iph), "=d" (ihl)
  55                  : "0" (sum), "1" (iph), "2" (ihl)
  56                  : "d0");
  57         return ~sum;
  58 }
  59
  60 /*
  61  *      Fold a partial checksum
  62  */
  63
  64 static inline unsigned int csum_fold(unsigned int sum)
  65 {
  66         unsigned int tmp = sum;
  67         __asm__("swap %1\n\t"
  68                 "addw %1, %0\n\t"
  69                 "clrw %1\n\t"
  70                 "addxw %1, %0"
  71                 : "=&d" (sum), "=&d" (tmp)
  72                 : "0" (sum), "1" (sum));
  73         return ~sum;
  74 }
  75
  76
  77 /*
  78  * computes the checksum of the TCP/UDP pseudo-header
  79  * returns a 16-bit checksum, already complemented
  80  */
  81
  82 static inline unsigned int
  83 csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len,
  84                   unsigned short proto, unsigned int sum)
  85 {
  86         __asm__ ("addl  %1,%0\n\t"
  87                  "addxl %4,%0\n\t"
  88                  "addxl %5,%0\n\t"
  89                  "clrl %1\n\t"
  90                  "addxl %1,%0"
  91                  : "=&d" (sum), "=&d" (saddr)
  92                  : "0" (daddr), "1" (saddr), "d" (len + proto),
  93                    "d"(sum));
  94         return sum;
  95 }
  96
  97 static inline unsigned short int
  98 csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len,
  99                   unsigned short proto, unsigned int sum)
 100 {
 101         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 102 }
 103
 104 /*
 105  * this routine is used for miscellaneous IP-like checksums, mainly
 106  * in icmp.c
 107  */
 108
 109 static inline unsigned short
 110 ip_compute_csum(unsigned char * buff, int len)
 111 {
 112         return csum_fold (csum_partial(buff, len, 0));
 113 }
 114
 115 #define _HAVE_ARCH_IPV6_CSUM
 116 static __inline__ unsigned short int
 117 csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr,
 118                 __u32 len, unsigned short proto, unsigned int sum)
 119 {
 120         register unsigned long tmp;
 121         __asm__("addl %2@,%0\n\t"
 122                 "movel %2@(4),%1\n\t"
 123                 "addxl %1,%0\n\t"
 124                 "movel %2@(8),%1\n\t"
 125                 "addxl %1,%0\n\t"
 126                 "movel %2@(12),%1\n\t"
 127                 "addxl %1,%0\n\t"
 128                 "movel %3@,%1\n\t"
 129                 "addxl %1,%0\n\t"
 130                 "movel %3@(4),%1\n\t"
 131                 "addxl %1,%0\n\t"
 132                 "movel %3@(8),%1\n\t"
 133                 "addxl %1,%0\n\t"
 134                 "movel %3@(12),%1\n\t"
 135                 "addxl %1,%0\n\t"
 136                 "addxl %4,%0\n\t"
 137                 "clrl %1\n\t"
 138                 "addxl %1,%0"
 139                 : "=&d" (sum), "=&d" (tmp)
 140                 : "a" (saddr), "a" (daddr), "d" (len + proto),
 141                   "0" (sum));
 142
 143         return csum_fold(sum);
 144 }
 145
 146 #endif /* _M68K_CHECKSUM_H */