include/asm-sh/checksum.h

   1 #ifndef __ASM_SH_CHECKSUM_H
   2 #define __ASM_SH_CHECKSUM_H
   3
   4 /*
   5  * This file is subject to the terms and conditions of the GNU General Public
   6  * License.  See the file "COPYING" in the main directory of this archive
   7  * for more details.
   8  *
   9  * Copyright (C) 1999 by Kaz Kojima & Niibe Yutaka
  10  */
  11
  12 #include <linux/in6.h>
  13
  14 /*
  15  * computes the checksum of a memory block at buff, length len,
  16  * and adds in "sum" (32-bit)
  17  *
  18  * returns a 32-bit number suitable for feeding into itself
  19  * or csum_tcpudp_magic
  20  *
  21  * this function must be called with even lengths, except
  22  * for the last fragment, which may be odd
  23  *
  24  * it's best to have buff aligned on a 32-bit boundary
  25  */
  26 asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
  27
  28 /*
  29  * the same as csum_partial, but copies from src while it
  30  * checksums, and handles user-space pointer exceptions correctly, when needed.
  31  *
  32  * here even more important to align src and dst on a 32-bit (or even
  33  * better 64-bit) boundary
  34  */
  35
  36 asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
  37                                           int len, __wsum sum, int *src_err_ptr, int *dst_err_ptr);
  38
  39 /*
  40  *      Note: when you get a NULL pointer exception here this means someone
  41  *      passed in an incorrect kernel address to one of these functions.
  42  *
  43  *      If you use these functions directly please don't forget the
  44  *      access_ok().
  45  */
  46 static __inline__
  47 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
  48                                         int len, __wsum sum)
  49 {
  50         return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
  51 }
  52
  53 static __inline__
  54 __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  55                                                 int len, __wsum sum, int *err_ptr)
  56 {
  57         return csum_partial_copy_generic((__force const void *)src, dst,
  58                                         len, sum, err_ptr, NULL);
  59 }
  60
  61 /*
  62  *      Fold a partial checksum
  63  */
  64
  65 static __inline__ __sum16 csum_fold(__wsum sum)
  66 {
  67         unsigned int __dummy;
  68         __asm__("swap.w %0, %1\n\t"
  69                 "extu.w %0, %0\n\t"
  70                 "extu.w %1, %1\n\t"
  71                 "add    %1, %0\n\t"
  72                 "swap.w %0, %1\n\t"
  73                 "add    %1, %0\n\t"
  74                 "not    %0, %0\n\t"
  75                 : "=r" (sum), "=&r" (__dummy)
  76                 : "0" (sum)
  77                 : "t");
  78         return (__force __sum16)sum;
  79 }
  80
  81 /*
  82  *      This is a version of ip_compute_csum() optimized for IP headers,
  83  *      which always checksum on 4 octet boundaries.
  84  *
  85  *      i386 version by Jorge Cwik <jorge@laser.satlink.net>, adapted
  86  *      for linux by * Arnt Gulbrandsen.
  87  */
  88 static __inline__ __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  89 {
  90         unsigned int sum, __dummy0, __dummy1;
  91
  92         __asm__ __volatile__(
  93                 "mov.l  @%1+, %0\n\t"
  94                 "mov.l  @%1+, %3\n\t"
  95                 "add    #-2, %2\n\t"
  96                 "clrt\n\t"
  97                 "1:\t"
  98                 "addc   %3, %0\n\t"
  99                 "movt   %4\n\t"
 100                 "mov.l  @%1+, %3\n\t"
 101                 "dt     %2\n\t"
 102                 "bf/s   1b\n\t"
 103                 " cmp/eq #1, %4\n\t"
 104                 "addc   %3, %0\n\t"
 105                 "addc   %2, %0"     /* Here %2 is 0, add carry-bit */
 106         /* Since the input registers which are loaded with iph and ihl
 107            are modified, we must also specify them as outputs, or gcc
 108            will assume they contain their original values. */
 109         : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
 110         : "1" (iph), "2" (ihl)
 111         : "t");
 112
 113         return  csum_fold(sum);
 114 }
 115
 116 static __inline__ __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 117                                                    unsigned short len,
 118                                                    unsigned short proto,
 119                                                    __wsum sum)
 120 {
 121 #ifdef __LITTLE_ENDIAN__
 122         unsigned long len_proto = (proto + len) << 8;
 123 #else
 124         unsigned long len_proto = proto + len;
 125 #endif
 126         __asm__("clrt\n\t"
 127                 "addc   %0, %1\n\t"
 128                 "addc   %2, %1\n\t"
 129                 "addc   %3, %1\n\t"
 130                 "movt   %0\n\t"
 131                 "add    %1, %0"
 132                 : "=r" (sum), "=r" (len_proto)
 133                 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum)
 134                 : "t");
 135         return sum;
 136 }
 137
 138 /*
 139  * computes the checksum of the TCP/UDP pseudo-header
 140  * returns a 16-bit checksum, already complemented
 141  */
 142 static __inline__ __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 143                                                        unsigned short len,
 144                                                        unsigned short proto,
 145                                                        __wsum sum)
 146 {
 147         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 148 }
 149
 150 /*
 151  * this routine is used for miscellaneous IP-like checksums, mainly
 152  * in icmp.c
 153  */
 154
 155 static __inline__ __sum16 ip_compute_csum(const void *buff, int len)
 156 {
 157     return csum_fold (csum_partial(buff, len, 0));
 158 }
 159
 160 #define _HAVE_ARCH_IPV6_CSUM
 161 #ifdef CONFIG_IPV6
 162 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 163                                           const struct in6_addr *daddr,
 164                                           __u32 len, unsigned short proto,
 165                                           __wsum sum)
 166 {
 167         unsigned int __dummy;
 168         __asm__("clrt\n\t"
 169                 "mov.l  @(0,%2), %1\n\t"
 170                 "addc   %1, %0\n\t"
 171                 "mov.l  @(4,%2), %1\n\t"
 172                 "addc   %1, %0\n\t"
 173                 "mov.l  @(8,%2), %1\n\t"
 174                 "addc   %1, %0\n\t"
 175                 "mov.l  @(12,%2), %1\n\t"
 176                 "addc   %1, %0\n\t"
 177                 "mov.l  @(0,%3), %1\n\t"
 178                 "addc   %1, %0\n\t"
 179                 "mov.l  @(4,%3), %1\n\t"
 180                 "addc   %1, %0\n\t"
 181                 "mov.l  @(8,%3), %1\n\t"
 182                 "addc   %1, %0\n\t"
 183                 "mov.l  @(12,%3), %1\n\t"
 184                 "addc   %1, %0\n\t"
 185                 "addc   %4, %0\n\t"
 186                 "addc   %5, %0\n\t"
 187                 "movt   %1\n\t"
 188                 "add    %1, %0\n"
 189                 : "=r" (sum), "=&r" (__dummy)
 190                 : "r" (saddr), "r" (daddr),
 191                   "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
 192                 : "t");
 193
 194         return csum_fold(sum);
 195 }
 196 #endif
 197
 198 /*
 199  *      Copy and checksum to user
 200  */
 201 #define HAVE_CSUM_COPY_USER
 202 static __inline__ __wsum csum_and_copy_to_user (const void *src,
 203                                                       void __user *dst,
 204                                                       int len, __wsum sum,
 205                                                       int *err_ptr)
 206 {
 207         if (access_ok(VERIFY_WRITE, dst, len))
 208                 return csum_partial_copy_generic((__force const void *)src,
 209                                                 dst, len, sum, NULL, err_ptr);
 210
 211         if (len)
 212                 *err_ptr = -EFAULT;
 213
 214         return (__force __wsum)-1; /* invalid checksum */
 215 }
 216 #endif /* __ASM_SH_CHECKSUM_H */