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