include/asm-sh/checksum.h

   1 #ifndef __ASM_SH_CHECKSUM_H
   2 #define __ASM_SH_CHECKSUM_H
   3
   4 /*
   5  * This file is subject to the terms and conditions of the GNU General Public
   6  * License.  See the file "COPYING" in the main directory of this archive
   7  * for more details.
   8  *
   9  * Copyright (C) 1999 by Kaz Kojima & Niibe Yutaka
  10  */
  11
  12 #include <linux/config.h>
  13 #include <linux/in6.h>
  14
  15 /*
  16  * computes the checksum of a memory block at buff, length len,
  17  * and adds in "sum" (32-bit)
  18  *
  19  * returns a 32-bit number suitable for feeding into itself
  20  * or csum_tcpudp_magic
  21  *
  22  * this function must be called with even lengths, except
  23  * for the last fragment, which may be odd
  24  *
  25  * it's best to have buff aligned on a 32-bit boundary
  26  */
  27 asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
  28
  29 /*
  30  * the same as csum_partial, but copies from src while it
  31  * checksums, and handles user-space pointer exceptions correctly, when needed.
  32  *
  33  * here even more important to align src and dst on a 32-bit (or even
  34  * better 64-bit) boundary
  35  */
  36
  37 asmlinkage unsigned int csum_partial_copy_generic(const unsigned char *src, unsigned char *dst,
  38                                                   int len, int sum, int *src_err_ptr, int *dst_err_ptr);
  39
  40 /*
  41  *      Note: when you get a NULL pointer exception here this means someone
  42  *      passed in an incorrect kernel address to one of these functions.
  43  *
  44  *      If you use these functions directly please don't forget the
  45  *      access_ok().
  46  */
  47 static __inline__
  48 unsigned int csum_partial_copy_nocheck (const unsigned char *src, unsigned char *dst,
  49                                         int len, int sum)
  50 {
  51         return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
  52 }
  53
  54 static __inline__
  55 unsigned int csum_partial_copy_from_user (const unsigned char *src, unsigned char *dst,
  56                                                 int len, int sum, int *err_ptr)
  57 {
  58         return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);
  59 }
  60
  61 /*
  62  *      Fold a partial checksum
  63  */
  64
  65 static __inline__ unsigned int csum_fold(unsigned int sum)
  66 {
  67         unsigned int __dummy;
  68         __asm__("swap.w %0, %1\n\t"
  69                 "extu.w %0, %0\n\t"
  70                 "extu.w %1, %1\n\t"
  71                 "add    %1, %0\n\t"
  72                 "swap.w %0, %1\n\t"
  73                 "add    %1, %0\n\t"
  74                 "not    %0, %0\n\t"
  75                 : "=r" (sum), "=&r" (__dummy)
  76                 : "0" (sum)
  77                 : "t");
  78         return sum;
  79 }
  80
  81 /*
  82  *      This is a version of ip_compute_csum() optimized for IP headers,
  83  *      which always checksum on 4 octet boundaries.
  84  *
  85  *      i386 version by Jorge Cwik <jorge@laser.satlink.net>, adapted
  86  *      for linux by * Arnt Gulbrandsen.
  87  */
  88 static __inline__ unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl)
  89 {
  90         unsigned int sum, __dummy0, __dummy1;
  91
  92         __asm__ __volatile__(
  93                 "mov.l  @%1+, %0\n\t"
  94                 "mov.l  @%1+, %3\n\t"
  95                 "add    #-2, %2\n\t"
  96                 "clrt\n\t"
  97                 "1:\t"
  98                 "addc   %3, %0\n\t"
  99                 "movt   %4\n\t"
 100                 "mov.l  @%1+, %3\n\t"
 101                 "dt     %2\n\t"
 102                 "bf/s   1b\n\t"
 103                 " cmp/eq #1, %4\n\t"
 104                 "addc   %3, %0\n\t"
 105                 "addc   %2, %0"     /* Here %2 is 0, add carry-bit */
 106         /* Since the input registers which are loaded with iph and ihl
 107            are modified, we must also specify them as outputs, or gcc
 108            will assume they contain their original values. */
 109         : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
 110         : "1" (iph), "2" (ihl)
 111         : "t");
 112
 113         return  csum_fold(sum);
 114 }
 115
 116 static __inline__ unsigned long csum_tcpudp_nofold(unsigned long saddr,
 117                                                    unsigned long daddr,
 118                                                    unsigned short len,
 119                                                    unsigned short proto,
 120                                                    unsigned int sum)
 121 {
 122 #ifdef __LITTLE_ENDIAN__
 123         unsigned long len_proto = (ntohs(len)<<16)+proto*256;
 124 #else
 125         unsigned long len_proto = (proto<<16)+len;
 126 #endif
 127         __asm__("clrt\n\t"
 128                 "addc   %0, %1\n\t"
 129                 "addc   %2, %1\n\t"
 130                 "addc   %3, %1\n\t"
 131                 "movt   %0\n\t"
 132                 "add    %1, %0"
 133                 : "=r" (sum), "=r" (len_proto)
 134                 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum)
 135                 : "t");
 136         return sum;
 137 }
 138
 139 /*
 140  * computes the checksum of the TCP/UDP pseudo-header
 141  * returns a 16-bit checksum, already complemented
 142  */
 143 static __inline__ unsigned short int csum_tcpudp_magic(unsigned long saddr,
 144                                                        unsigned long daddr,
 145                                                        unsigned short len,
 146                                                        unsigned short proto,
 147                                                        unsigned int sum)
 148 {
 149         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 150 }
 151
 152 /*
 153  * this routine is used for miscellaneous IP-like checksums, mainly
 154  * in icmp.c
 155  */
 156
 157 static __inline__ unsigned short ip_compute_csum(unsigned char * buff, int len)
 158 {
 159     return csum_fold (csum_partial(buff, len, 0));
 160 }
 161
 162 #define _HAVE_ARCH_IPV6_CSUM
 163 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
 164                                                      struct in6_addr *daddr,
 165                                                      __u32 len,
 166                                                      unsigned short proto,
 167                                                      unsigned int sum)
 168 {
 169         unsigned int __dummy;
 170         __asm__("clrt\n\t"
 171                 "mov.l  @(0,%2), %1\n\t"
 172                 "addc   %1, %0\n\t"
 173                 "mov.l  @(4,%2), %1\n\t"
 174                 "addc   %1, %0\n\t"
 175                 "mov.l  @(8,%2), %1\n\t"
 176                 "addc   %1, %0\n\t"
 177                 "mov.l  @(12,%2), %1\n\t"
 178                 "addc   %1, %0\n\t"
 179                 "mov.l  @(0,%3), %1\n\t"
 180                 "addc   %1, %0\n\t"
 181                 "mov.l  @(4,%3), %1\n\t"
 182                 "addc   %1, %0\n\t"
 183                 "mov.l  @(8,%3), %1\n\t"
 184                 "addc   %1, %0\n\t"
 185                 "mov.l  @(12,%3), %1\n\t"
 186                 "addc   %1, %0\n\t"
 187                 "addc   %4, %0\n\t"
 188                 "addc   %5, %0\n\t"
 189                 "movt   %1\n\t"
 190                 "add    %1, %0\n"
 191                 : "=r" (sum), "=&r" (__dummy)
 192                 : "r" (saddr), "r" (daddr),
 193                   "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
 194                 : "t");
 195
 196         return csum_fold(sum);
 197 }
 198
 199 /*
 200  *      Copy and checksum to user
 201  */
 202 #define HAVE_CSUM_COPY_USER
 203 static __inline__ unsigned int csum_and_copy_to_user (const unsigned char *src,
 204                                                       unsigned char __user *dst,
 205                                                       int len, int sum,
 206                                                       int *err_ptr)
 207 {
 208         if (access_ok(VERIFY_WRITE, dst, len))
 209                 return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
 210
 211         if (len)
 212                 *err_ptr = -EFAULT;
 213
 214         return -1; /* invalid checksum */
 215 }
 216 #endif /* __ASM_SH_CHECKSUM_H */