i386/linux-2.3.21/include/asm-mips/checksum.h

   1 /* $Id: checksum.h,v 1.6 1998/09/16 13:30:51 ralf Exp $
   2  *
   3  * This file is subject to the terms and conditions of the GNU General Public
   4  * License.  See the file "COPYING" in the main directory of this archive
   5  * for more details.
   6  *
   7  * Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle
   8  */
   9 #ifndef __ASM_MIPS_CHECKSUM_H
  10 #define __ASM_MIPS_CHECKSUM_H
  11
  12 /*
  13  * computes the checksum of a memory block at buff, length len,
  14  * and adds in "sum" (32-bit)
  15  *
  16  * returns a 32-bit number suitable for feeding into itself
  17  * or csum_tcpudp_magic
  18  *
  19  * this function must be called with even lengths, except
  20  * for the last fragment, which may be odd
  21  *
  22  * it's best to have buff aligned on a 32-bit boundary
  23  */
  24 unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
  25
  26 /*
  27  * this is a new version of the above that records errors it finds in *errp,
  28  * but continues and zeros the rest of the buffer.
  29  */
  30 #define csum_partial_copy_nocheck csum_partial_copy
  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 char *src, char *dst, int len,
  37                                          unsigned int sum, int *errp);
  38
  39 #define HAVE_CSUM_COPY_USER
  40 unsigned int csum_and_copy_to_user (const char *src, char *dst,
  41                                     int len, int sum, int *err_ptr);
  42
  43 /*
  44  * the same as csum_partial, but copies from user space (but on MIPS
  45  * we have just one address space, so this is identical to the above)
  46  *
  47  * this is obsolete and will go away.
  48  */
  49 #define csum_partial_copy_fromuser csum_partial_copy
  50 unsigned int csum_partial_copy(const char *src, char *dst, int len, unsigned int sum);
  51
  52 /*
  53  *      Fold a partial checksum without adding pseudo headers
  54  */
  55 static inline unsigned short int csum_fold(unsigned int sum)
  56 {
  57         __asm__("
  58         .set    noat
  59         sll     $1,%0,16
  60         addu    %0,$1
  61         sltu    $1,%0,$1
  62         srl     %0,%0,16
  63         addu    %0,$1
  64         xori    %0,0xffff
  65         .set    at"
  66         : "=r" (sum)
  67         : "0" (sum)
  68         : "$1");
  69
  70         return sum;
  71 }
  72
  73 /*
  74  *      This is a version of ip_compute_csum() optimized for IP headers,
  75  *      which always checksum on 4 octet boundaries.
  76  *
  77  *      By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
  78  *      Arnt Gulbrandsen.
  79  */
  80 static inline unsigned short ip_fast_csum(unsigned char * iph,
  81                                           unsigned int ihl)
  82 {
  83         unsigned int sum;
  84         unsigned long dummy;
  85
  86         /*
  87          * This is for 32-bit MIPS processors.
  88          */
  89         __asm__ __volatile__("
  90         .set    noreorder
  91         .set    noat
  92         lw      %0,(%1)
  93         subu    %2,4
  94         #blez   %2,2f
  95         sll     %2,2                    # delay slot
  96
  97         lw      %3,4(%1)
  98         addu    %2,%1                   # delay slot
  99         addu    %0,%3
 100         sltu    $1,%0,%3
 101         lw      %3,8(%1)
 102         addu    %0,$1
 103         addu    %0,%3
 104         sltu    $1,%0,%3
 105         lw      %3,12(%1)
 106         addu    %0,$1
 107         addu    %0,%3
 108         sltu    $1,%0,%3
 109         addu    %0,$1
 110
 111 1:      lw      %3,16(%1)
 112         addiu   %1,4
 113         addu    %0,%3
 114         sltu    $1,%0,%3
 115         bne     %2,%1,1b
 116         addu    %0,$1                   # delay slot
 117
 118 2:      .set    at
 119         .set    reorder"
 120         : "=&r" (sum), "=&r" (iph), "=&r" (ihl), "=&r" (dummy)
 121         : "1" (iph), "2" (ihl)
 122         : "$1");
 123
 124         return csum_fold(sum);
 125 }
 126
 127 /*
 128  * computes the checksum of the TCP/UDP pseudo-header
 129  * returns a 16-bit checksum, already complemented
 130  */
 131 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
 132                                                unsigned long daddr,
 133                                                unsigned short len,
 134                                                unsigned short proto,
 135                                                unsigned int sum)
 136 {
 137     __asm__("
 138         .set    noat
 139         addu    %0,%2
 140         sltu    $1,%0,%2
 141         addu    %0,$1
 142
 143         addu    %0,%3
 144         sltu    $1,%0,%3
 145         addu    %0,$1
 146
 147         addu    %0,%4
 148         sltu    $1,%0,%4
 149         addu    %0,$1
 150         .set    at"
 151         : "=r" (sum)
 152         : "0" (daddr), "r"(saddr),
 153 #ifdef __MIPSEL__
 154             "r" ((ntohs(len)<<16)+proto*256),
 155 #else
 156             "r" (((proto)<<16)+len),
 157 #endif
 158             "r"(sum)
 159         : "$1");
 160
 161         return sum;
 162 }
 163
 164 /*
 165  * computes the checksum of the TCP/UDP pseudo-header
 166  * returns a 16-bit checksum, already complemented
 167  */
 168 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
 169                                                    unsigned long daddr,
 170                                                    unsigned short len,
 171                                                    unsigned short proto,
 172                                                    unsigned int sum)
 173 {
 174         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 175 }
 176
 177 /*
 178  * this routine is used for miscellaneous IP-like checksums, mainly
 179  * in icmp.c
 180  */
 181 static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
 182 {
 183         return csum_fold(csum_partial(buff, len, 0));
 184 }
 185
 186 #define _HAVE_ARCH_IPV6_CSUM
 187 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
 188                                                      struct in6_addr *daddr,
 189                                                      __u16 len,
 190                                                      unsigned short proto,
 191                                                      unsigned int sum)
 192 {
 193         __asm__("
 194                 .set    noreorder
 195                 .set    noat
 196                 addu    %0,%5           # proto (long in network byte order)
 197                 sltu    $1,%0,%5
 198                 addu    %0,$1
 199
 200                 addu    %0,%6           # csum
 201                 sltu    $1,%0,%6
 202                 lw      %1,0(%2)        # four words source address
 203                 addu    %0,$1
 204                 addu    %0,%1
 205                 sltu    $1,%0,$1
 206
 207                 lw      %1,4(%2)
 208                 addu    %0,$1
 209                 addu    %0,%1
 210                 sltu    $1,%0,$1
 211
 212                 lw      %1,8(%2)
 213                 addu    %0,$1
 214                 addu    %0,%1
 215                 sltu    $1,%0,$1
 216
 217                 lw      %1,12(%2)
 218                 addu    %0,$1
 219                 addu    %0,%1
 220                 sltu    $1,%0,$1
 221
 222                 lw      %1,0(%3)
 223                 addu    %0,$1
 224                 addu    %0,%1
 225                 sltu    $1,%0,$1
 226
 227                 lw      %1,4(%3)
 228                 addu    %0,$1
 229                 addu    %0,%1
 230                 sltu    $1,%0,$1
 231
 232                 lw      %1,8(%3)
 233                 addu    %0,$1
 234                 addu    %0,%1
 235                 sltu    $1,%0,$1
 236
 237                 lw      %1,12(%3)
 238                 addu    %0,$1
 239                 addu    %0,%1
 240                 sltu    $1,%0,$1
 241                 .set    noat
 242                 .set    noreorder"
 243                 : "=r" (sum),
 244                   "=r" (proto)
 245                 : "r" (saddr),
 246                   "r" (daddr),
 247                   "0" (htonl((__u32) (len))),
 248                   "1" (htonl(proto)),
 249                   "r"(sum)
 250                 : "$1");
 251
 252         return csum_fold(sum);
 253 }
 254
 255 #endif /* __ASM_MIPS_CHECKSUM_H */