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/config.h>
  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 unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum);
  32
  33 /*
  34  * this is a new version of the above that records errors it finds in *errp,
  35  * but continues and zeros the rest of the buffer.
  36  */
  37 unsigned int csum_partial_copy_from_user(const unsigned char __user *src,
  38                                          unsigned char *dst, int len,
  39                                          unsigned int sum, int *errp);
  40
  41 /*
  42  * Copy and checksum to user
  43  */
  44 #define HAVE_CSUM_COPY_USER
  45 static inline unsigned int csum_and_copy_to_user (const unsigned char *src,
  46                                                   unsigned char __user *dst,
  47                                                   int len, int sum,
  48                                                   int *err_ptr)
  49 {
  50         might_sleep();
  51         sum = csum_partial(src, len, sum);
  52
  53         if (copy_to_user(dst, src, len)) {
  54                 *err_ptr = -EFAULT;
  55                 return -1;
  56         }
  57
  58         return sum;
  59 }
  60
  61 /*
  62  * the same as csum_partial, but copies from user space (but on MIPS
  63  * we have just one address space, so this is identical to the above)
  64  */
  65 unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst,
  66                                        int len, unsigned int sum);
  67
  68 /*
  69  *      Fold a partial checksum without adding pseudo headers
  70  */
  71 static inline unsigned short int csum_fold(unsigned int sum)
  72 {
  73         __asm__(
  74         "       .set    push            # csum_fold\n"
  75         "       .set    noat            \n"
  76         "       sll     $1, %0, 16      \n"
  77         "       addu    %0, $1          \n"
  78         "       sltu    $1, %0, $1      \n"
  79         "       srl     %0, %0, 16      \n"
  80         "       addu    %0, $1          \n"
  81         "       xori    %0, 0xffff      \n"
  82         "       .set    pop"
  83         : "=r" (sum)
  84         : "0" (sum));
  85
  86         return sum;
  87 }
  88
  89 /*
  90  *      This is a version of ip_compute_csum() optimized for IP headers,
  91  *      which always checksum on 4 octet boundaries.
  92  *
  93  *      By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
  94  *      Arnt Gulbrandsen.
  95  */
  96 static inline unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl)
  97 {
  98         unsigned int *word = (unsigned int *) iph;
  99         unsigned int *stop = word + ihl;
 100         unsigned int csum;
 101         int carry;
 102
 103         csum = word[0];
 104         csum += word[1];
 105         carry = (csum < word[1]);
 106         csum += carry;
 107
 108         csum += word[2];
 109         carry = (csum < word[2]);
 110         csum += carry;
 111
 112         csum += word[3];
 113         carry = (csum < word[3]);
 114         csum += carry;
 115
 116         word += 4;
 117         do {
 118                 csum += *word;
 119                 carry = (csum < *word);
 120                 csum += carry;
 121                 word++;
 122         } while (word != stop);
 123
 124         return csum_fold(csum);
 125 }
 126
 127 static inline unsigned int csum_tcpudp_nofold(unsigned long saddr,
 128         unsigned long daddr, unsigned short len, unsigned short proto,
 129         unsigned int sum)
 130 {
 131         __asm__(
 132         "       .set    push            # csum_tcpudp_nofold\n"
 133         "       .set    noat            \n"
 134 #ifdef CONFIG_32BIT
 135         "       addu    %0, %2          \n"
 136         "       sltu    $1, %0, %2      \n"
 137         "       addu    %0, $1          \n"
 138
 139         "       addu    %0, %3          \n"
 140         "       sltu    $1, %0, %3      \n"
 141         "       addu    %0, $1          \n"
 142
 143         "       addu    %0, %4          \n"
 144         "       sltu    $1, %0, %4      \n"
 145         "       addu    %0, $1          \n"
 146 #endif
 147 #ifdef CONFIG_64BIT
 148         "       daddu   %0, %2          \n"
 149         "       daddu   %0, %3          \n"
 150         "       daddu   %0, %4          \n"
 151         "       dsll32  $1, %0, 0       \n"
 152         "       daddu   %0, $1          \n"
 153         "       dsra32  %0, %0, 0       \n"
 154 #endif
 155         "       .set    pop"
 156         : "=r" (sum)
 157         : "0" (daddr), "r"(saddr),
 158 #ifdef __MIPSEL__
 159           "r" (((unsigned long)htons(len)<<16) + proto*256),
 160 #else
 161           "r" (((unsigned long)(proto)<<16) + len),
 162 #endif
 163           "r" (sum));
 164
 165         return sum;
 166 }
 167
 168 /*
 169  * computes the checksum of the TCP/UDP pseudo-header
 170  * returns a 16-bit checksum, already complemented
 171  */
 172 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
 173                                                    unsigned long daddr,
 174                                                    unsigned short len,
 175                                                    unsigned short proto,
 176                                                    unsigned int sum)
 177 {
 178         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 179 }
 180
 181 /*
 182  * this routine is used for miscellaneous IP-like checksums, mainly
 183  * in icmp.c
 184  */
 185 static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
 186 {
 187         return csum_fold(csum_partial(buff, len, 0));
 188 }
 189
 190 #define _HAVE_ARCH_IPV6_CSUM
 191 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
 192                                                      struct in6_addr *daddr,
 193                                                      __u32 len,
 194                                                      unsigned short proto,
 195                                                      unsigned int sum)
 196 {
 197         __asm__(
 198         "       .set    push            # csum_ipv6_magic\n"
 199         "       .set    noreorder       \n"
 200         "       .set    noat            \n"
 201         "       addu    %0, %5          # proto (long in network byte order)\n"
 202         "       sltu    $1, %0, %5      \n"
 203         "       addu    %0, $1          \n"
 204
 205         "       addu    %0, %6          # csum\n"
 206         "       sltu    $1, %0, %6      \n"
 207         "       lw      %1, 0(%2)       # four words source address\n"
 208         "       addu    %0, $1          \n"
 209         "       addu    %0, %1          \n"
 210         "       sltu    $1, %0, %1      \n"
 211
 212         "       lw      %1, 4(%2)       \n"
 213         "       addu    %0, $1          \n"
 214         "       addu    %0, %1          \n"
 215         "       sltu    $1, %0, %1      \n"
 216
 217         "       lw      %1, 8(%2)       \n"
 218         "       addu    %0, $1          \n"
 219         "       addu    %0, %1          \n"
 220         "       sltu    $1, %0, %1      \n"
 221
 222         "       lw      %1, 12(%2)      \n"
 223         "       addu    %0, $1          \n"
 224         "       addu    %0, %1          \n"
 225         "       sltu    $1, %0, %1      \n"
 226
 227         "       lw      %1, 0(%3)       \n"
 228         "       addu    %0, $1          \n"
 229         "       addu    %0, %1          \n"
 230         "       sltu    $1, %0, %1      \n"
 231
 232         "       lw      %1, 4(%3)       \n"
 233         "       addu    %0, $1          \n"
 234         "       addu    %0, %1          \n"
 235         "       sltu    $1, %0, %1      \n"
 236
 237         "       lw      %1, 8(%3)       \n"
 238         "       addu    %0, $1          \n"
 239         "       addu    %0, %1          \n"
 240         "       sltu    $1, %0, %1      \n"
 241
 242         "       lw      %1, 12(%3)      \n"
 243         "       addu    %0, $1          \n"
 244         "       addu    %0, %1          \n"
 245         "       sltu    $1, %0, %1      \n"
 246
 247         "       addu    %0, $1          # Add final carry\n"
 248         "       .set    pop"
 249         : "=r" (sum), "=r" (proto)
 250         : "r" (saddr), "r" (daddr),
 251           "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
 252
 253         return csum_fold(sum);
 254 }
 255
 256 #endif /* _ASM_CHECKSUM_H */