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 unsigned char __user *src,
  29                                                 unsigned char *dst,
  30                                                 int len, int sum,
  31                                                 int *csum_err);
  32
  33 extern unsigned int csum_partial_copy_nocheck(const unsigned char *src,
  34                                               unsigned char *dst, int len,
  35                                               int 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  */
  42 static inline unsigned short
  43 ip_fast_csum(unsigned char *iph, unsigned int ihl)
  44 {
  45         unsigned int sum = 0;
  46         unsigned long tmp;
  47
  48         __asm__ ("subqw #1,%2\n"
  49                  "1:\t"
  50                  "movel %1@+,%3\n\t"
  51                  "addxl %3,%0\n\t"
  52                  "dbra  %2,1b\n\t"
  53                  "movel %0,%3\n\t"
  54                  "swap  %3\n\t"
  55                  "addxw %3,%0\n\t"
  56                  "clrw  %3\n\t"
  57                  "addxw %3,%0\n\t"
  58                  : "=d" (sum), "=&a" (iph), "=&d" (ihl), "=&d" (tmp)
  59                  : "0" (sum), "1" (iph), "2" (ihl)
  60                  : "memory");
  61         return ~sum;
  62 }
  63
  64 /*
  65  *      Fold a partial checksum
  66  */
  67
  68 static inline unsigned int csum_fold(unsigned int sum)
  69 {
  70         unsigned int tmp = sum;
  71         __asm__("swap %1\n\t"
  72                 "addw %1, %0\n\t"
  73                 "clrw %1\n\t"
  74                 "addxw %1, %0"
  75                 : "=&d" (sum), "=&d" (tmp)
  76                 : "0" (sum), "1" (tmp));
  77         return ~sum;
  78 }
  79
  80
  81 static inline unsigned int
  82 csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len,
  83                   unsigned short proto, unsigned int sum)
  84 {
  85         __asm__ ("addl  %2,%0\n\t"
  86                  "addxl %3,%0\n\t"
  87                  "addxl %4,%0\n\t"
  88                  "clrl %1\n\t"
  89                  "addxl %1,%0"
  90                  : "=&d" (sum), "=d" (saddr)
  91                  : "g" (daddr), "1" (saddr), "d" (len + proto),
  92                    "0" (sum));
  93         return sum;
  94 }
  95
  96
  97 /*
  98  * computes the checksum of the TCP/UDP pseudo-header
  99  * returns a 16-bit checksum, already complemented
 100  */
 101 static inline unsigned short int
 102 csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len,
 103                   unsigned short proto, unsigned int sum)
 104 {
 105         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 106 }
 107
 108 /*
 109  * this routine is used for miscellaneous IP-like checksums, mainly
 110  * in icmp.c
 111  */
 112
 113 static inline unsigned short
 114 ip_compute_csum(unsigned char * buff, int len)
 115 {
 116         return csum_fold (csum_partial(buff, len, 0));
 117 }
 118
 119 #define _HAVE_ARCH_IPV6_CSUM
 120 static __inline__ unsigned short int
 121 csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr,
 122                 __u32 len, unsigned short proto, unsigned int sum)
 123 {
 124         register unsigned long tmp;
 125         __asm__("addl %2@,%0\n\t"
 126                 "movel %2@(4),%1\n\t"
 127                 "addxl %1,%0\n\t"
 128                 "movel %2@(8),%1\n\t"
 129                 "addxl %1,%0\n\t"
 130                 "movel %2@(12),%1\n\t"
 131                 "addxl %1,%0\n\t"
 132                 "movel %3@,%1\n\t"
 133                 "addxl %1,%0\n\t"
 134                 "movel %3@(4),%1\n\t"
 135                 "addxl %1,%0\n\t"
 136                 "movel %3@(8),%1\n\t"
 137                 "addxl %1,%0\n\t"
 138                 "movel %3@(12),%1\n\t"
 139                 "addxl %1,%0\n\t"
 140                 "addxl %4,%0\n\t"
 141                 "clrl %1\n\t"
 142                 "addxl %1,%0"
 143                 : "=&d" (sum), "=&d" (tmp)
 144                 : "a" (saddr), "a" (daddr), "d" (len + proto),
 145                   "0" (sum));
 146
 147         return csum_fold(sum);
 148 }
 149
 150 #endif /* _M68K_CHECKSUM_H */