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