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\tnoat\t\t\t# csum_fold\n\t"
  75         "sll\t$1,%0,16\n\t"
  76         "addu\t%0,$1\n\t"
  77         "sltu\t$1,%0,$1\n\t"
  78         "srl\t%0,%0,16\n\t"
  79         "addu\t%0,$1\n\t"
  80         "xori\t%0,0xffff\n\t"
  81         ".set\tat"
  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\tnoat\t\t\t# csum_tcpudp_nofold\n\t"
 132 #ifdef CONFIG_32BIT
 133         "addu\t%0, %2\n\t"
 134         "sltu\t$1, %0, %2\n\t"
 135         "addu\t%0, $1\n\t"
 136
 137         "addu\t%0, %3\n\t"
 138         "sltu\t$1, %0, %3\n\t"
 139         "addu\t%0, $1\n\t"
 140
 141         "addu\t%0, %4\n\t"
 142         "sltu\t$1, %0, %4\n\t"
 143         "addu\t%0, $1\n\t"
 144 #endif
 145 #ifdef CONFIG_64BIT
 146         "daddu\t%0, %2\n\t"
 147         "daddu\t%0, %3\n\t"
 148         "daddu\t%0, %4\n\t"
 149         "dsll32\t$1, %0, 0\n\t"
 150         "daddu\t%0, $1\n\t"
 151         "dsrl32\t%0, %0, 0\n\t"
 152 #endif
 153         ".set\tat"
 154         : "=r" (sum)
 155         : "0" (daddr), "r"(saddr),
 156 #ifdef __MIPSEL__
 157           "r" (((unsigned long)htons(len)<<16) + proto*256),
 158 #else
 159           "r" (((unsigned long)(proto)<<16) + 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 unsigned short int csum_tcpudp_magic(unsigned long saddr,
 171                                                    unsigned long daddr,
 172                                                    unsigned short len,
 173                                                    unsigned short proto,
 174                                                    unsigned int sum)
 175 {
 176         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
 177 }
 178
 179 /*
 180  * this routine is used for miscellaneous IP-like checksums, mainly
 181  * in icmp.c
 182  */
 183 static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
 184 {
 185         return csum_fold(csum_partial(buff, len, 0));
 186 }
 187
 188 #define _HAVE_ARCH_IPV6_CSUM
 189 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
 190                                                      struct in6_addr *daddr,
 191                                                      __u32 len,
 192                                                      unsigned short proto,
 193                                                      unsigned int sum)
 194 {
 195         __asm__(
 196         ".set\tpush\t\t\t# csum_ipv6_magic\n\t"
 197         ".set\tnoreorder\n\t"
 198         ".set\tnoat\n\t"
 199         "addu\t%0, %5\t\t\t# proto (long in network byte order)\n\t"
 200         "sltu\t$1, %0, %5\n\t"
 201         "addu\t%0, $1\n\t"
 202
 203         "addu\t%0, %6\t\t\t# csum\n\t"
 204         "sltu\t$1, %0, %6\n\t"
 205         "lw\t%1, 0(%2)\t\t\t# four words source address\n\t"
 206         "addu\t%0, $1\n\t"
 207         "addu\t%0, %1\n\t"
 208         "sltu\t$1, %0, %1\n\t"
 209
 210         "lw\t%1, 4(%2)\n\t"
 211         "addu\t%0, $1\n\t"
 212         "addu\t%0, %1\n\t"
 213         "sltu\t$1, %0, %1\n\t"
 214
 215         "lw\t%1, 8(%2)\n\t"
 216         "addu\t%0, $1\n\t"
 217         "addu\t%0, %1\n\t"
 218         "sltu\t$1, %0, %1\n\t"
 219
 220         "lw\t%1, 12(%2)\n\t"
 221         "addu\t%0, $1\n\t"
 222         "addu\t%0, %1\n\t"
 223         "sltu\t$1, %0, %1\n\t"
 224
 225         "lw\t%1, 0(%3)\n\t"
 226         "addu\t%0, $1\n\t"
 227         "addu\t%0, %1\n\t"
 228         "sltu\t$1, %0, %1\n\t"
 229
 230         "lw\t%1, 4(%3)\n\t"
 231         "addu\t%0, $1\n\t"
 232         "addu\t%0, %1\n\t"
 233         "sltu\t$1, %0, %1\n\t"
 234
 235         "lw\t%1, 8(%3)\n\t"
 236         "addu\t%0, $1\n\t"
 237         "addu\t%0, %1\n\t"
 238         "sltu\t$1, %0, %1\n\t"
 239
 240         "lw\t%1, 12(%3)\n\t"
 241         "addu\t%0, $1\n\t"
 242         "addu\t%0, %1\n\t"
 243         "sltu\t$1, %0, %1\n\t"
 244
 245         "addu\t%0, $1\t\t\t# Add final carry\n\t"
 246         ".set\tpop"
 247         : "=r" (sum), "=r" (proto)
 248         : "r" (saddr), "r" (daddr),
 249           "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
 250
 251         return csum_fold(sum);
 252 }
 253
 254 #endif /* _ASM_CHECKSUM_H */