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#include <linux/in6.h>
  16
  17#include <asm/uaccess.h>
  18
  19/*
  20 * computes the checksum of a memory block at buff, length len,
  21 * and adds in "sum" (32-bit)
  22 *
  23 * returns a 32-bit number suitable for feeding into itself
  24 * or csum_tcpudp_magic
  25 *
  26 * this function must be called with even lengths, except
  27 * for the last fragment, which may be odd
  28 *
  29 * it's best to have buff aligned on a 32-bit boundary
  30 */
  31__wsum csum_partial(const void *buff, int len, __wsum sum);
  32
  33__wsum __csum_partial_copy_kernel(const void *src, void *dst,
  34                                  int len, __wsum sum, int *err_ptr);
  35
  36__wsum __csum_partial_copy_from_user(const void *src, void *dst,
  37                                     int len, __wsum sum, int *err_ptr);
  38__wsum __csum_partial_copy_to_user(const void *src, void *dst,
  39                                   int len, __wsum sum, int *err_ptr);
  40/*
  41 * this is a new version of the above that records errors it finds in *errp,
  42 * but continues and zeros the rest of the buffer.
  43 */
  44static inline
  45__wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len,
  46                                   __wsum sum, int *err_ptr)
  47{
  48        might_fault();
  49        if (segment_eq(get_fs(), get_ds()))
  50                return __csum_partial_copy_kernel((__force void *)src, dst,
  51                                                  len, sum, err_ptr);
  52        else
  53                return __csum_partial_copy_from_user((__force void *)src, dst,
  54                                                     len, sum, err_ptr);
  55}
  56
  57#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
  58static inline
  59__wsum csum_and_copy_from_user(const void __user *src, void *dst,
  60                               int len, __wsum sum, int *err_ptr)
  61{
  62        if (access_ok(VERIFY_READ, src, len))
  63                return csum_partial_copy_from_user(src, dst, len, sum,
  64                                                   err_ptr);
  65        if (len)
  66                *err_ptr = -EFAULT;
  67
  68        return sum;
  69}
  70
  71/*
  72 * Copy and checksum to user
  73 */
  74#define HAVE_CSUM_COPY_USER
  75static inline
  76__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
  77                             __wsum sum, int *err_ptr)
  78{
  79        might_fault();
  80        if (access_ok(VERIFY_WRITE, dst, len)) {
  81                if (segment_eq(get_fs(), get_ds()))
  82                        return __csum_partial_copy_kernel(src,
  83                                                          (__force void *)dst,
  84                                                          len, sum, err_ptr);
  85                else
  86                        return __csum_partial_copy_to_user(src,
  87                                                           (__force void *)dst,
  88                                                           len, sum, err_ptr);
  89        }
  90        if (len)
  91                *err_ptr = -EFAULT;
  92
  93        return (__force __wsum)-1; /* invalid checksum */
  94}
  95
  96/*
  97 * the same as csum_partial, but copies from user space (but on MIPS
  98 * we have just one address space, so this is identical to the above)
  99 */
 100__wsum csum_partial_copy_nocheck(const void *src, void *dst,
 101                                       int len, __wsum sum);
 102
 103/*
 104 *      Fold a partial checksum without adding pseudo headers
 105 */
 106static inline __sum16 csum_fold(__wsum sum)
 107{
 108        __asm__(
 109        "       .set    push            # csum_fold\n"
 110        "       .set    noat            \n"
 111        "       sll     $1, %0, 16      \n"
 112        "       addu    %0, $1          \n"
 113        "       sltu    $1, %0, $1      \n"
 114        "       srl     %0, %0, 16      \n"
 115        "       addu    %0, $1          \n"
 116        "       xori    %0, 0xffff      \n"
 117        "       .set    pop"
 118        : "=r" (sum)
 119        : "0" (sum));
 120
 121        return (__force __sum16)sum;
 122}
 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
 162static inline __wsum csum_tcpudp_nofold(__be32 saddr,
 163        __be32 daddr, unsigned short len, unsigned short proto,
 164        __wsum sum)
 165{
 166        __asm__(
 167        "       .set    push            # csum_tcpudp_nofold\n"
 168        "       .set    noat            \n"
 169#ifdef CONFIG_32BIT
 170        "       addu    %0, %2          \n"
 171        "       sltu    $1, %0, %2      \n"
 172        "       addu    %0, $1          \n"
 173
 174        "       addu    %0, %3          \n"
 175        "       sltu    $1, %0, %3      \n"
 176        "       addu    %0, $1          \n"
 177
 178        "       addu    %0, %4          \n"
 179        "       sltu    $1, %0, %4      \n"
 180        "       addu    %0, $1          \n"
 181#endif
 182#ifdef CONFIG_64BIT
 183        "       daddu   %0, %2          \n"
 184        "       daddu   %0, %3          \n"
 185        "       daddu   %0, %4          \n"
 186        "       dsll32  $1, %0, 0       \n"
 187        "       daddu   %0, $1          \n"
 188        "       dsra32  %0, %0, 0       \n"
 189#endif
 190        "       .set    pop"
 191        : "=r" (sum)
 192        : "0" ((__force unsigned long)daddr),
 193          "r" ((__force unsigned long)saddr),
 194#ifdef __MIPSEL__
 195          "r" ((proto + len) << 8),
 196#else
 197          "r" (proto + len),
 198#endif
 199          "r" ((__force unsigned long)sum));
 200
 201        return sum;
 202}
 203
 204/*
 205 * computes the checksum of the TCP/UDP pseudo-header
 206 * returns a 16-bit checksum, already complemented
 207 */
 208static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
 209                                                   unsigned short len,
 210                                                   unsigned short proto,
 211                                                   __wsum sum)
 212{
 213        return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 214}
 215
 216/*
 217 * this routine is used for miscellaneous IP-like checksums, mainly
 218 * in icmp.c
 219 */
 220static inline __sum16 ip_compute_csum(const void *buff, int len)
 221{
 222        return csum_fold(csum_partial(buff, len, 0));
 223}
 224
 225#define _HAVE_ARCH_IPV6_CSUM
 226static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 227                                          const struct in6_addr *daddr,
 228                                          __u32 len, unsigned short proto,
 229                                          __wsum sum)
 230{
 231        __asm__(
 232        "       .set    push            # csum_ipv6_magic\n"
 233        "       .set    noreorder       \n"
 234        "       .set    noat            \n"
 235        "       addu    %0, %5          # proto (long in network byte order)\n"
 236        "       sltu    $1, %0, %5      \n"
 237        "       addu    %0, $1          \n"
 238
 239        "       addu    %0, %6          # csum\n"
 240        "       sltu    $1, %0, %6      \n"
 241        "       lw      %1, 0(%2)       # four words source address\n"
 242        "       addu    %0, $1          \n"
 243        "       addu    %0, %1          \n"
 244        "       sltu    $1, %0, %1      \n"
 245
 246        "       lw      %1, 4(%2)       \n"
 247        "       addu    %0, $1          \n"
 248        "       addu    %0, %1          \n"
 249        "       sltu    $1, %0, %1      \n"
 250
 251        "       lw      %1, 8(%2)       \n"
 252        "       addu    %0, $1          \n"
 253        "       addu    %0, %1          \n"
 254        "       sltu    $1, %0, %1      \n"
 255
 256        "       lw      %1, 12(%2)      \n"
 257        "       addu    %0, $1          \n"
 258        "       addu    %0, %1          \n"
 259        "       sltu    $1, %0, %1      \n"
 260
 261        "       lw      %1, 0(%3)       \n"
 262        "       addu    %0, $1          \n"
 263        "       addu    %0, %1          \n"
 264        "       sltu    $1, %0, %1      \n"
 265
 266        "       lw      %1, 4(%3)       \n"
 267        "       addu    %0, $1          \n"
 268        "       addu    %0, %1          \n"
 269        "       sltu    $1, %0, %1      \n"
 270
 271        "       lw      %1, 8(%3)       \n"
 272        "       addu    %0, $1          \n"
 273        "       addu    %0, %1          \n"
 274        "       sltu    $1, %0, %1      \n"
 275
 276        "       lw      %1, 12(%3)      \n"
 277        "       addu    %0, $1          \n"
 278        "       addu    %0, %1          \n"
 279        "       sltu    $1, %0, %1      \n"
 280
 281        "       addu    %0, $1          # Add final carry\n"
 282        "       .set    pop"
 283        : "=r" (sum), "=r" (proto)
 284        : "r" (saddr), "r" (daddr),
 285          "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
 286
 287        return csum_fold(sum);
 288}
 289
 290#endif /* _ASM_CHECKSUM_H */
 291