LXR linux/arch/mips/include/asm/checksum.h

   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * Copyright (C) 1995, 96, 97, 98, 99, 2001 by Ralf Baechle
   7 * Copyright (C) 1999 Silicon Graphics, Inc.
   8 * Copyright (C) 2001 Thiemo Seufer.
   9 * Copyright (C) 2002 Maciej W. Rozycki
  10 * Copyright (C) 2014 Imagination Technologies Ltd.
  11 */
  12#ifndef _ASM_CHECKSUM_H
  13#define _ASM_CHECKSUM_H
  14
  15#ifdef CONFIG_GENERIC_CSUM
  16#include <asm-generic/checksum.h>
  17#else
  18
  19#include <linux/in6.h>
  20
  21#include <linux/uaccess.h>
  22
  23/*
  24 * computes the checksum of a memory block at buff, length len,
  25 * and adds in "sum" (32-bit)
  26 *
  27 * returns a 32-bit number suitable for feeding into itself
  28 * or csum_tcpudp_magic
  29 *
  30 * this function must be called with even lengths, except
  31 * for the last fragment, which may be odd
  32 *
  33 * it's best to have buff aligned on a 32-bit boundary
  34 */
  35__wsum csum_partial(const void *buff, int len, __wsum sum);
  36
  37__wsum __csum_partial_copy_kernel(const void *src, void *dst,
  38                                  int len, __wsum sum, int *err_ptr);
  39
  40__wsum __csum_partial_copy_from_user(const void *src, void *dst,
  41                                     int len, __wsum sum, int *err_ptr);
  42__wsum __csum_partial_copy_to_user(const void *src, void *dst,
  43                                   int len, __wsum sum, int *err_ptr);
  44/*
  45 * this is a new version of the above that records errors it finds in *errp,
  46 * but continues and zeros the rest of the buffer.
  47 */
  48static inline
  49__wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len,
  50                                   __wsum sum, int *err_ptr)
  51{
  52        might_fault();
  53        if (uaccess_kernel())
  54                return __csum_partial_copy_kernel((__force void *)src, dst,
  55                                                  len, sum, err_ptr);
  56        else
  57                return __csum_partial_copy_from_user((__force void *)src, dst,
  58                                                     len, sum, err_ptr);
  59}
  60
  61#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
  62static inline
  63__wsum csum_and_copy_from_user(const void __user *src, void *dst,
  64                               int len, __wsum sum, int *err_ptr)
  65{
  66        if (access_ok(src, len))
  67                return csum_partial_copy_from_user(src, dst, len, sum,
  68                                                   err_ptr);
  69        if (len)
  70                *err_ptr = -EFAULT;
  71
  72        return sum;
  73}
  74
  75/*
  76 * Copy and checksum to user
  77 */
  78#define HAVE_CSUM_COPY_USER
  79static inline
  80__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
  81                             __wsum sum, int *err_ptr)
  82{
  83        might_fault();
  84        if (access_ok(dst, len)) {
  85                if (uaccess_kernel())
  86                        return __csum_partial_copy_kernel(src,
  87                                                          (__force void *)dst,
  88                                                          len, sum, err_ptr);
  89                else
  90                        return __csum_partial_copy_to_user(src,
  91                                                           (__force void *)dst,
  92                                                           len, sum, err_ptr);
  93        }
  94        if (len)
  95                *err_ptr = -EFAULT;
  96
  97        return (__force __wsum)-1; /* invalid checksum */
  98}
  99
 100/*
 101 * the same as csum_partial, but copies from user space (but on MIPS
 102 * we have just one address space, so this is identical to the above)
 103 */
 104__wsum csum_partial_copy_nocheck(const void *src, void *dst,
 105                                       int len, __wsum sum);
 106#define csum_partial_copy_nocheck csum_partial_copy_nocheck
 107
 108/*
 109 *      Fold a partial checksum without adding pseudo headers
 110 */
 111static inline __sum16 csum_fold(__wsum csum)
 112{
 113        u32 sum = (__force u32)csum;
 114
 115        sum += (sum << 16);
 116        csum = (__force __wsum)(sum < (__force u32)csum);
 117        sum >>= 16;
 118        sum += (__force u32)csum;
 119
 120        return (__force __sum16)~sum;
 121}
 122#define csum_fold csum_fold
 123
 124/*
 125 *      This is a version of ip_compute_csum() optimized for IP headers,
 126 *      which always checksum on 4 octet boundaries.
 127 *
 128 *      By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
 129 *      Arnt Gulbrandsen.
 130 */
 131static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
 132{
 133        const unsigned int *word = iph;
 134        const unsigned int *stop = word + ihl;
 135        unsigned int csum;
 136        int carry;
 137
 138        csum = word[0];
 139        csum += word[1];
 140        carry = (csum < word[1]);
 141        csum += carry;
 142
 143        csum += word[2];
 144        carry = (csum < word[2]);
 145        csum += carry;
 146
 147        csum += word[3];
 148        carry = (csum < word[3]);
 149        csum += carry;
 150
 151        word += 4;
 152        do {
 153                csum += *word;
 154                carry = (csum < *word);
 155                csum += carry;
 156                word++;
 157        } while (word != stop);
 158
 159        return csum_fold(csum);
 160}
 161#define ip_fast_csum ip_fast_csum
 162
 163static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 164                                        __u32 len, __u8 proto,
 165                                        __wsum sum)
 166{
 167        __asm__(
 168        "       .set    push            # csum_tcpudp_nofold\n"
 169        "       .set    noat            \n"
 170#ifdef CONFIG_32BIT
 171        "       addu    %0, %2          \n"
 172        "       sltu    $1, %0, %2      \n"
 173        "       addu    %0, $1          \n"
 174
 175        "       addu    %0, %3          \n"
 176        "       sltu    $1, %0, %3      \n"
 177        "       addu    %0, $1          \n"
 178
 179        "       addu    %0, %4          \n"
 180        "       sltu    $1, %0, %4      \n"
 181        "       addu    %0, $1          \n"
 182#endif
 183#ifdef CONFIG_64BIT
 184        "       daddu   %0, %2          \n"
 185        "       daddu   %0, %3          \n"
 186        "       daddu   %0, %4          \n"
 187        "       dsll32  $1, %0, 0       \n"
 188        "       daddu   %0, $1          \n"
 189        "       sltu    $1, %0, $1      \n"
 190        "       dsra32  %0, %0, 0       \n"
 191        "       addu    %0, $1          \n"
 192#endif
 193        "       .set    pop"
 194        : "=r" (sum)
 195        : "0" ((__force unsigned long)daddr),
 196          "r" ((__force unsigned long)saddr),
 197#ifdef __MIPSEL__
 198          "r" ((proto + len) << 8),
 199#else
 200          "r" (proto + len),
 201#endif
 202          "r" ((__force unsigned long)sum));
 203
 204        return sum;
 205}
 206#define csum_tcpudp_nofold csum_tcpudp_nofold
 207
 208/*
 209 * this routine is used for miscellaneous IP-like checksums, mainly
 210 * in icmp.c
 211 */
 212static inline __sum16 ip_compute_csum(const void *buff, int len)
 213{
 214        return csum_fold(csum_partial(buff, len, 0));
 215}
 216
 217#define _HAVE_ARCH_IPV6_CSUM
 218static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 219                                          const struct in6_addr *daddr,
 220                                          __u32 len, __u8 proto,
 221                                          __wsum sum)
 222{
 223        __wsum tmp;
 224
 225        __asm__(
 226        "       .set    push            # csum_ipv6_magic\n"
 227        "       .set    noreorder       \n"
 228        "       .set    noat            \n"
 229        "       addu    %0, %5          # proto (long in network byte order)\n"
 230        "       sltu    $1, %0, %5      \n"
 231        "       addu    %0, $1          \n"
 232
 233        "       addu    %0, %6          # csum\n"
 234        "       sltu    $1, %0, %6      \n"
 235        "       lw      %1, 0(%2)       # four words source address\n"
 236        "       addu    %0, $1          \n"
 237        "       addu    %0, %1          \n"
 238        "       sltu    $1, %0, %1      \n"
 239
 240        "       lw      %1, 4(%2)       \n"
 241        "       addu    %0, $1          \n"
 242        "       addu    %0, %1          \n"
 243        "       sltu    $1, %0, %1      \n"
 244
 245        "       lw      %1, 8(%2)       \n"
 246        "       addu    %0, $1          \n"
 247        "       addu    %0, %1          \n"
 248        "       sltu    $1, %0, %1      \n"
 249
 250        "       lw      %1, 12(%2)      \n"
 251        "       addu    %0, $1          \n"
 252        "       addu    %0, %1          \n"
 253        "       sltu    $1, %0, %1      \n"
 254
 255        "       lw      %1, 0(%3)       \n"
 256        "       addu    %0, $1          \n"
 257        "       addu    %0, %1          \n"
 258        "       sltu    $1, %0, %1      \n"
 259
 260        "       lw      %1, 4(%3)       \n"
 261        "       addu    %0, $1          \n"
 262        "       addu    %0, %1          \n"
 263        "       sltu    $1, %0, %1      \n"
 264
 265        "       lw      %1, 8(%3)       \n"
 266        "       addu    %0, $1          \n"
 267        "       addu    %0, %1          \n"
 268        "       sltu    $1, %0, %1      \n"
 269
 270        "       lw      %1, 12(%3)      \n"
 271        "       addu    %0, $1          \n"
 272        "       addu    %0, %1          \n"
 273        "       sltu    $1, %0, %1      \n"
 274
 275        "       addu    %0, $1          # Add final carry\n"
 276        "       .set    pop"
 277        : "=&r" (sum), "=&r" (tmp)
 278        : "r" (saddr), "r" (daddr),
 279          "0" (htonl(len)), "r" (htonl(proto)), "r" (sum));
 280
 281        return csum_fold(sum);
 282}
 283
 284#include <asm-generic/checksum.h>
 285#endif /* CONFIG_GENERIC_CSUM */
 286
 287#endif /* _ASM_CHECKSUM_H */
 288