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 *src, 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\tnoat\t\t\t# csum_fold\n\t"
  74         "sll\t$1,%0,16\n\t"
  75         "addu\t%0,$1\n\t"
  76         "sltu\t$1,%0,$1\n\t"
  77         "srl\t%0,%0,16\n\t"
  78         "addu\t%0,$1\n\t"
  79         "xori\t%0,0xffff\n\t"
  80         ".set\tat"
  81         : "=r" (sum)
  82         : "0" (sum));
  83
  84         return 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 unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl)
  95 {
  96         unsigned int *word = (unsigned int *) iph;
  97         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 unsigned int csum_tcpudp_nofold(unsigned long saddr,
 126         unsigned long daddr, unsigned short len, unsigned short proto,
 127         unsigned int sum)
 128 {
 129         __asm__(
 130         ".set\tnoat\t\t\t# csum_tcpudp_nofold\n\t"
 131 #ifdef CONFIG_MIPS32
 132         "addu\t%0, %2\n\t"
 133         "sltu\t$1, %0, %2\n\t"
 134         "addu\t%0, $1\n\t"
 135
 136         "addu\t%0, %3\n\t"
 137         "sltu\t$1, %0, %3\n\t"
 138         "addu\t%0, $1\n\t"
 139
 140         "addu\t%0, %4\n\t"
 141         "sltu\t$1, %0, %4\n\t"
 142         "addu\t%0, $1\n\t"
 143 #endif
 144 #ifdef CONFIG_MIPS64
 145         "daddu\t%0, %2\n\t"
 146         "daddu\t%0, %3\n\t"
 147         "daddu\t%0, %4\n\t"
 148         "dsll32\t$1, %0, 0\n\t"
 149         "daddu\t%0, $1\n\t"
 150         "dsrl32\t%0, %0, 0\n\t"
 151 #endif
 152         ".set\tat"
 153         : "=r" (sum)
 154         : "0" (daddr), "r"(saddr),
 155 #ifdef __MIPSEL__
 156           "r" (((unsigned long)htons(len)<<16) + proto*256),
 157 #else
 158           "r" (((unsigned long)(proto)<<16) + len),
 159 #endif
 160           "r" (sum));
 161
 162         return sum;
 163 }
 164
 165 /*
 166  * computes the checksum of the TCP/UDP pseudo-header
 167  * returns a 16-bit checksum, already complemented
 168  */
 169 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
 170                                                    unsigned long daddr,
 171                                                    unsigned short len,
 172                                                    unsigned short proto,
 173                                                    unsigned int 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 unsigned short ip_compute_csum(unsigned char * buff, int len)
 183 {
 184         return csum_fold(csum_partial(buff, len, 0));
 185 }
 186
 187 #define _HAVE_ARCH_IPV6_CSUM
 188 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
 189                                                      struct in6_addr *daddr,
 190                                                      __u32 len,
 191                                                      unsigned short proto,
 192                                                      unsigned int sum)
 193 {
 194         __asm__(
 195         ".set\tpush\t\t\t# csum_ipv6_magic\n\t"
 196         ".set\tnoreorder\n\t"
 197         ".set\tnoat\n\t"
 198         "addu\t%0, %5\t\t\t# proto (long in network byte order)\n\t"
 199         "sltu\t$1, %0, %5\n\t"
 200         "addu\t%0, $1\n\t"
 201
 202         "addu\t%0, %6\t\t\t# csum\n\t"
 203         "sltu\t$1, %0, %6\n\t"
 204         "lw\t%1, 0(%2)\t\t\t# four words source address\n\t"
 205         "addu\t%0, $1\n\t"
 206         "addu\t%0, %1\n\t"
 207         "sltu\t$1, %0, %1\n\t"
 208
 209         "lw\t%1, 4(%2)\n\t"
 210         "addu\t%0, $1\n\t"
 211         "addu\t%0, %1\n\t"
 212         "sltu\t$1, %0, %1\n\t"
 213
 214         "lw\t%1, 8(%2)\n\t"
 215         "addu\t%0, $1\n\t"
 216         "addu\t%0, %1\n\t"
 217         "sltu\t$1, %0, %1\n\t"
 218
 219         "lw\t%1, 12(%2)\n\t"
 220         "addu\t%0, $1\n\t"
 221         "addu\t%0, %1\n\t"
 222         "sltu\t$1, %0, %1\n\t"
 223
 224         "lw\t%1, 0(%3)\n\t"
 225         "addu\t%0, $1\n\t"
 226         "addu\t%0, %1\n\t"
 227         "sltu\t$1, %0, %1\n\t"
 228
 229         "lw\t%1, 4(%3)\n\t"
 230         "addu\t%0, $1\n\t"
 231         "addu\t%0, %1\n\t"
 232         "sltu\t$1, %0, %1\n\t"
 233
 234         "lw\t%1, 8(%3)\n\t"
 235         "addu\t%0, $1\n\t"
 236         "addu\t%0, %1\n\t"
 237         "sltu\t$1, %0, %1\n\t"
 238
 239         "lw\t%1, 12(%3)\n\t"
 240         "addu\t%0, $1\n\t"
 241         "addu\t%0, %1\n\t"
 242         "sltu\t$1, %0, %1\n\t"
 243
 244         "addu\t%0, $1\t\t\t# Add final carry\n\t"
 245         ".set\tpop"
 246         : "=r" (sum), "=r" (proto)
 247         : "r" (saddr), "r" (daddr),
 248           "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
 249
 250         return csum_fold(sum);
 251 }
 252
 253 #endif /* _ASM_CHECKSUM_H */