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, 1996, 1997, 1998, 2001 by Ralf Baechle
   7  */
   8 #ifndef _ASM_CHECKSUM_H
   9 #define _ASM_CHECKSUM_H
  10
  11 #include <asm/uaccess.h>
  12 #include <linux/in6.h>
  13
  14 /*
  15  * computes the checksum of a memory block at buff, length len,
  16  * and adds in "sum" (32-bit)
  17  *
  18  * returns a 32-bit number suitable for feeding into itself
  19  * or csum_tcpudp_magic
  20  *
  21  * this function must be called with even lengths, except
  22  * for the last fragment, which may be odd
  23  *
  24  * it's best to have buff aligned on a 32-bit boundary
  25  */
  26 unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum);
  27
  28 /*
  29  * this is a new version of the above that records errors it finds in *errp,
  30  * but continues and zeros the rest of the buffer.
  31  */
  32 unsigned int csum_partial_copy_from_user(const char *src, char *dst, int len,
  33                                          unsigned int sum, int *errp);
  34
  35 /*
  36  * Copy and checksum to user
  37  */
  38 #define HAVE_CSUM_COPY_USER
  39 static inline unsigned int csum_and_copy_to_user (const char *src, char *dst,
  40                                                   int len, int sum,
  41                                                   int *err_ptr)
  42 {
  43         sum = csum_partial(src, len, sum);
  44
  45         if (copy_to_user(dst, src, len)) {
  46                 *err_ptr = -EFAULT;
  47                 return -1;
  48         }
  49
  50         return sum;
  51 }
  52
  53 /*
  54  * the same as csum_partial, but copies from user space (but on MIPS
  55  * we have just one address space, so this is identical to the above)
  56  */
  57 unsigned int csum_partial_copy_nocheck(const char *src, char *dst, int len,
  58                                        unsigned int sum);
  59
  60 /*
  61  *      Fold a partial checksum without adding pseudo headers
  62  */
  63 static inline unsigned short int csum_fold(unsigned int sum)
  64 {
  65         __asm__(
  66         ".set\tnoat\t\t\t# csum_fold\n\t"
  67         "sll\t$1,%0,16\n\t"
  68         "addu\t%0,$1\n\t"
  69         "sltu\t$1,%0,$1\n\t"
  70         "srl\t%0,%0,16\n\t"
  71         "addu\t%0,$1\n\t"
  72         "xori\t%0,0xffff\n\t"
  73         ".set\tat"
  74         : "=r" (sum)
  75         : "0" (sum));
  76
  77         return sum;
  78 }
  79
  80 /*
  81  *      This is a version of ip_compute_csum() optimized for IP headers,
  82  *      which always checksum on 4 octet boundaries.
  83  *
  84  *      By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
  85  *      Arnt Gulbrandsen.
  86  */
  87 static inline unsigned short ip_fast_csum(unsigned char *iph,
  88                                           unsigned int ihl)
  89 {
  90         unsigned int sum;
  91         unsigned long dummy;
  92
  93         /*
  94          * This is for 32-bit MIPS processors.
  95          */
  96         __asm__ __volatile__(
  97         ".set\tnoreorder\t\t\t# ip_fast_csum\n\t"
  98         ".set\tnoat\n\t"
  99         "lw\t%0, (%1)\n\t"
 100         "subu\t%2, 4\n\t"
 101         "#blez\t%2, 2f\n\t"
 102         " sll\t%2, 2\n\t"
 103         "lw\t%3, 4(%1)\n\t"
 104         "addu\t%2, %1\n\t"
 105         "addu\t%0, %3\n\t"
 106         "sltu\t$1, %0, %3\n\t"
 107         "lw\t%3, 8(%1)\n\t"
 108         "addu\t%0, $1\n\t"
 109         "addu\t%0, %3\n\t"
 110         "sltu\t$1, %0, %3\n\t"
 111         "lw\t%3, 12(%1)\n\t"
 112         "addu\t%0, $1\n\t"
 113         "addu\t%0, %3\n\t"
 114         "sltu\t$1, %0, %3\n\t"
 115         "addu\t%0, $1\n"
 116
 117         "1:\tlw\t%3, 16(%1)\n\t"
 118         "addiu\t%1, 4\n\t"
 119         "addu\t%0, %3\n\t"
 120         "sltu\t$1, %0, %3\n\t"
 121         "bne\t%2, %1, 1b\n\t"
 122         " addu\t%0, $1\n"
 123
 124         "2:\t.set\tat\n\t"
 125         ".set\treorder"
 126         : "=&r" (sum), "=&r" (iph), "=&r" (ihl), "=&r" (dummy)
 127         : "1" (iph), "2" (ihl));
 128
 129         return csum_fold(sum);
 130 }
 131
 132 /*
 133  * computes the checksum of the TCP/UDP pseudo-header
 134  * returns a 16-bit checksum, already complemented
 135  */
 136 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
 137                                                unsigned long daddr,
 138                                                unsigned short len,
 139                                                unsigned short proto,
 140                                                unsigned int sum)
 141 {
 142         __asm__(
 143         ".set\tnoat\t\t\t# csum_tcpudp_nofold\n\t"
 144         "addu\t%0, %2\n\t"
 145         "sltu\t$1, %0, %2\n\t"
 146         "addu\t%0, $1\n\t"
 147
 148         "addu\t%0, %3\n\t"
 149         "sltu\t$1, %0, %3\n\t"
 150         "addu\t%0, $1\n\t"
 151
 152         "addu\t%0, %4\n\t"
 153         "sltu\t$1, %0, %4\n\t"
 154         "addu\t%0, $1\n\t"
 155         ".set\tat"
 156         : "=r" (sum)
 157         : "0" (daddr), "r"(saddr),
 158 #ifdef __MIPSEL__
 159           "r" ((ntohs(len)<<16)+proto*256),
 160 #else
 161           "r" (((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\tpush\t\t\t# csum_ipv6_magic\n\t"
 199         ".set\tnoreorder\n\t"
 200         ".set\tnoat\n\t"
 201         "addu\t%0, %5\t\t\t# proto (long in network byte order)\n\t"
 202         "sltu\t$1, %0, %5\n\t"
 203         "addu\t%0, $1\n\t"
 204
 205         "addu\t%0, %6\t\t\t# csum\n\t"
 206         "sltu\t$1, %0, %6\n\t"
 207         "lw\t%1, 0(%2)\t\t\t# four words source address\n\t"
 208         "addu\t%0, $1\n\t"
 209         "addu\t%0, %1\n\t"
 210         "sltu\t$1, %0, %1\n\t"
 211
 212         "lw\t%1, 4(%2)\n\t"
 213         "addu\t%0, $1\n\t"
 214         "addu\t%0, %1\n\t"
 215         "sltu\t$1, %0, %1\n\t"
 216
 217         "lw\t%1, 8(%2)\n\t"
 218         "addu\t%0, $1\n\t"
 219         "addu\t%0, %1\n\t"
 220         "sltu\t$1, %0, %1\n\t"
 221
 222         "lw\t%1, 12(%2)\n\t"
 223         "addu\t%0, $1\n\t"
 224         "addu\t%0, %1\n\t"
 225         "sltu\t$1, %0, %1\n\t"
 226
 227         "lw\t%1, 0(%3)\n\t"
 228         "addu\t%0, $1\n\t"
 229         "addu\t%0, %1\n\t"
 230         "sltu\t$1, %0, %1\n\t"
 231
 232         "lw\t%1, 4(%3)\n\t"
 233         "addu\t%0, $1\n\t"
 234         "addu\t%0, %1\n\t"
 235         "sltu\t$1, %0, %1\n\t"
 236
 237         "lw\t%1, 8(%3)\n\t"
 238         "addu\t%0, $1\n\t"
 239         "addu\t%0, %1\n\t"
 240         "sltu\t$1, %0, %1\n\t"
 241
 242         "lw\t%1, 12(%3)\n\t"
 243         "addu\t%0, $1\n\t"
 244         "addu\t%0, %1\n\t"
 245         "sltu\t$1, %0, %1\n\t"
 246
 247         "addu\t%0, $1\t\t\t# Add final carry\n\t"
 248         ".set\tpop"
 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 */