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_from_user(const void __user *src, void *dst, int len);
  38 __wsum __csum_partial_copy_to_user(const void *src, void __user *dst, int len);
  39
  40 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
  41 static inline
  42 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
  43 {
  44         might_fault();
  45         if (!access_ok(src, len))
  46                 return 0;
  47         return __csum_partial_copy_from_user(src, dst, len);
  48 }
  49
  50 /*
  51  * Copy and checksum to user
  52  */
  53 #define HAVE_CSUM_COPY_USER
  54 static inline
  55 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
  56 {
  57         might_fault();
  58         if (!access_ok(dst, len))
  59                 return 0;
  60         return __csum_partial_copy_to_user(src, dst, len);
  61 }
  62
  63 /*
  64  * the same as csum_partial, but copies from user space (but on MIPS
  65  * we have just one address space, so this is identical to the above)
  66  */
  67 #define _HAVE_ARCH_CSUM_AND_COPY
  68 __wsum __csum_partial_copy_nocheck(const void *src, void *dst, int len);
  69 static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
  70 {
  71         return __csum_partial_copy_nocheck(src, dst, len);
  72 }
  73
  74 /*
  75  *      Fold a partial checksum without adding pseudo headers
  76  */
  77 static inline __sum16 csum_fold(__wsum csum)
  78 {
  79         u32 sum = (__force u32)csum;
  80
  81         sum += (sum << 16);
  82         csum = (__force __wsum)(sum < (__force u32)csum);
  83         sum >>= 16;
  84         sum += (__force u32)csum;
  85
  86         return (__force __sum16)~sum;
  87 }
  88 #define csum_fold csum_fold
  89
  90 /*
  91  *      This is a version of ip_compute_csum() optimized for IP headers,
  92  *      which always checksum on 4 octet boundaries.
  93  *
  94  *      By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
  95  *      Arnt Gulbrandsen.
  96  */
  97 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  98 {
  99         const unsigned int *word = iph;
 100         const unsigned int *stop = word + ihl;
 101         unsigned int csum;
 102         int carry;
 103
 104         csum = word[0];
 105         csum += word[1];
 106         carry = (csum < word[1]);
 107         csum += carry;
 108
 109         csum += word[2];
 110         carry = (csum < word[2]);
 111         csum += carry;
 112
 113         csum += word[3];
 114         carry = (csum < word[3]);
 115         csum += carry;
 116
 117         word += 4;
 118         do {
 119                 csum += *word;
 120                 carry = (csum < *word);
 121                 csum += carry;
 122                 word++;
 123         } while (word != stop);
 124
 125         return csum_fold(csum);
 126 }
 127 #define ip_fast_csum ip_fast_csum
 128
 129 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 130                                         __u32 len, __u8 proto,
 131                                         __wsum isum)
 132 {
 133         const unsigned int sh32 = IS_ENABLED(CONFIG_64BIT) ? 32 : 0;
 134         unsigned long sum = (__force unsigned long)daddr;
 135         unsigned long tmp;
 136         __u32 osum;
 137
 138         tmp = (__force unsigned long)saddr;
 139         sum += tmp;
 140
 141         if (IS_ENABLED(CONFIG_32BIT))
 142                 sum += sum < tmp;
 143
 144         /*
 145          * We know PROTO + LEN has the sign bit clear, so cast to a signed
 146          * type to avoid an extraneous zero-extension where TMP is 64-bit.
 147          */
 148         tmp = (__s32)(proto + len);
 149         tmp <<= IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? 8 : 0;
 150         sum += tmp;
 151         if (IS_ENABLED(CONFIG_32BIT))
 152                 sum += sum < tmp;
 153
 154         tmp = (__force unsigned long)isum;
 155         sum += tmp;
 156
 157         if (IS_ENABLED(CONFIG_32BIT)) {
 158                 sum += sum < tmp;
 159                 osum = sum;
 160         } else if (IS_ENABLED(CONFIG_64BIT)) {
 161                 tmp = sum << sh32;
 162                 sum += tmp;
 163                 osum = sum < tmp;
 164                 osum += sum >> sh32;
 165         } else {
 166                 BUILD_BUG();
 167         }
 168
 169         return (__force __wsum)osum;
 170 }
 171 #define csum_tcpudp_nofold csum_tcpudp_nofold
 172
 173 /*
 174  * this routine is used for miscellaneous IP-like checksums, mainly
 175  * in icmp.c
 176  */
 177 static inline __sum16 ip_compute_csum(const void *buff, int len)
 178 {
 179         return csum_fold(csum_partial(buff, len, 0));
 180 }
 181
 182 #define _HAVE_ARCH_IPV6_CSUM
 183 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 184                                           const struct in6_addr *daddr,
 185                                           __u32 len, __u8 proto,
 186                                           __wsum sum)
 187 {
 188         __wsum tmp;
 189
 190         __asm__(
 191         "       .set    push            # csum_ipv6_magic\n"
 192         "       .set    noreorder       \n"
 193         "       .set    noat            \n"
 194         "       addu    %0, %5          # proto (long in network byte order)\n"
 195         "       sltu    $1, %0, %5      \n"
 196         "       addu    %0, $1          \n"
 197
 198         "       addu    %0, %6          # csum\n"
 199         "       sltu    $1, %0, %6      \n"
 200         "       lw      %1, 0(%2)       # four words source address\n"
 201         "       addu    %0, $1          \n"
 202         "       addu    %0, %1          \n"
 203         "       sltu    $1, %0, %1      \n"
 204
 205         "       lw      %1, 4(%2)       \n"
 206         "       addu    %0, $1          \n"
 207         "       addu    %0, %1          \n"
 208         "       sltu    $1, %0, %1      \n"
 209
 210         "       lw      %1, 8(%2)       \n"
 211         "       addu    %0, $1          \n"
 212         "       addu    %0, %1          \n"
 213         "       sltu    $1, %0, %1      \n"
 214
 215         "       lw      %1, 12(%2)      \n"
 216         "       addu    %0, $1          \n"
 217         "       addu    %0, %1          \n"
 218         "       sltu    $1, %0, %1      \n"
 219
 220         "       lw      %1, 0(%3)       \n"
 221         "       addu    %0, $1          \n"
 222         "       addu    %0, %1          \n"
 223         "       sltu    $1, %0, %1      \n"
 224
 225         "       lw      %1, 4(%3)       \n"
 226         "       addu    %0, $1          \n"
 227         "       addu    %0, %1          \n"
 228         "       sltu    $1, %0, %1      \n"
 229
 230         "       lw      %1, 8(%3)       \n"
 231         "       addu    %0, $1          \n"
 232         "       addu    %0, %1          \n"
 233         "       sltu    $1, %0, %1      \n"
 234
 235         "       lw      %1, 12(%3)      \n"
 236         "       addu    %0, $1          \n"
 237         "       addu    %0, %1          \n"
 238         "       sltu    $1, %0, %1      \n"
 239
 240         "       addu    %0, $1          # Add final carry\n"
 241         "       .set    pop"
 242         : "=&r" (sum), "=&r" (tmp)
 243         : "r" (saddr), "r" (daddr),
 244           "0" (htonl(len)), "r" (htonl(proto)), "r" (sum)
 245         : "memory");
 246
 247         return csum_fold(sum);
 248 }
 249
 250 #include <asm-generic/checksum.h>
 251 #endif /* CONFIG_GENERIC_CSUM */
 252
 253 #endif /* _ASM_CHECKSUM_H */