root/arch/m68k/include/asm/checksum.h

INCLUDED FROM

DEFINITIONS

1. ip_fast_csum
2. csum_fold
3. csum_tcpudp_nofold
4. csum_tcpudp_magic
5. ip_compute_csum
6. csum_ipv6_magic

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _M68K_CHECKSUM_H
   3 #define _M68K_CHECKSUM_H
   4 
   5 #include <linux/in6.h>
   6 
   7 #ifdef CONFIG_GENERIC_CSUM
   8 #include <asm-generic/checksum.h>
   9 #else
  10 
  11 /*
  12  * computes the checksum of a memory block at buff, length len,
  13  * and adds in "sum" (32-bit)
  14  *
  15  * returns a 32-bit number suitable for feeding into itself
  16  * or csum_tcpudp_magic
  17  *
  18  * this function must be called with even lengths, except
  19  * for the last fragment, which may be odd
  20  *
  21  * it's best to have buff aligned on a 32-bit boundary
  22  */
  23 __wsum csum_partial(const void *buff, int len, __wsum sum);
  24 
  25 /*
  26  * the same as csum_partial, but copies from src while it
  27  * checksums
  28  *
  29  * here even more important to align src and dst on a 32-bit (or even
  30  * better 64-bit) boundary
  31  */
  32 
  33 extern __wsum csum_partial_copy_from_user(const void __user *src,
  34                                                 void *dst,
  35                                                 int len, __wsum sum,
  36                                                 int *csum_err);
  37 
  38 extern __wsum csum_partial_copy_nocheck(const void *src,
  39                                               void *dst, int len,
  40                                               __wsum sum);
  41 
  42 /*
  43  *      This is a version of ip_fast_csum() optimized for IP headers,
  44  *      which always checksum on 4 octet boundaries.
  45  */
  46 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  47 {
  48         unsigned int sum = 0;
  49         unsigned long tmp;
  50 
  51         __asm__ ("subqw #1,%2\n"
  52                  "1:\t"
  53                  "movel %1@+,%3\n\t"
  54                  "addxl %3,%0\n\t"
  55                  "dbra  %2,1b\n\t"
  56                  "movel %0,%3\n\t"
  57                  "swap  %3\n\t"
  58                  "addxw %3,%0\n\t"
  59                  "clrw  %3\n\t"
  60                  "addxw %3,%0\n\t"
  61                  : "=d" (sum), "=&a" (iph), "=&d" (ihl), "=&d" (tmp)
  62                  : "0" (sum), "1" (iph), "2" (ihl)
  63                  : "memory");
  64         return (__force __sum16)~sum;
  65 }
  66 
  67 static inline __sum16 csum_fold(__wsum sum)
  68 {
  69         unsigned int tmp = (__force u32)sum;
  70 
  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 
  78         return (__force __sum16)~sum;
  79 }
  80 
  81 static inline __wsum
  82 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
  83                   unsigned short proto, __wsum 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 __sum16
 102 csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
 103                   unsigned short proto, __wsum 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 __sum16 ip_compute_csum(const void *buff, int len)
 114 {
 115         return csum_fold (csum_partial(buff, len, 0));
 116 }
 117 
 118 #define _HAVE_ARCH_IPV6_CSUM
 119 static __inline__ __sum16
 120 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
 121                 __u32 len, __u8 proto, __wsum sum)
 122 {
 123         register unsigned long tmp;
 124         __asm__("addl %2@,%0\n\t"
 125                 "movel %2@(4),%1\n\t"
 126                 "addxl %1,%0\n\t"
 127                 "movel %2@(8),%1\n\t"
 128                 "addxl %1,%0\n\t"
 129                 "movel %2@(12),%1\n\t"
 130                 "addxl %1,%0\n\t"
 131                 "movel %3@,%1\n\t"
 132                 "addxl %1,%0\n\t"
 133                 "movel %3@(4),%1\n\t"
 134                 "addxl %1,%0\n\t"
 135                 "movel %3@(8),%1\n\t"
 136                 "addxl %1,%0\n\t"
 137                 "movel %3@(12),%1\n\t"
 138                 "addxl %1,%0\n\t"
 139                 "addxl %4,%0\n\t"
 140                 "clrl %1\n\t"
 141                 "addxl %1,%0"
 142                 : "=&d" (sum), "=&d" (tmp)
 143                 : "a" (saddr), "a" (daddr), "d" (len + proto),
 144                   "0" (sum));
 145 
 146         return csum_fold(sum);
 147 }
 148 
 149 #endif /* CONFIG_GENERIC_CSUM */
 150 #endif /* _M68K_CHECKSUM_H */