include/asm-v850/checksum.h

   1 /*
   2  * include/asm-v850/checksum.h -- Checksum ops
   3  *
   4  *  Copyright (C) 2001  NEC Corporation
   5  *  Copyright (C) 2001  Miles Bader <miles@gnu.org>
   6  *
   7  * This file is subject to the terms and conditions of the GNU General
   8  * Public License.  See the file COPYING in the main directory of this
   9  * archive for more details.
  10  *
  11  * Written by Miles Bader <miles@gnu.org>
  12  */
  13
  14 #ifndef __V850_CHECKSUM_H__
  15 #define __V850_CHECKSUM_H__
  16
  17 /*
  18  * computes the checksum of a memory block at buff, length len,
  19  * and adds in "sum" (32-bit)
  20  *
  21  * returns a 32-bit number suitable for feeding into itself
  22  * or csum_tcpudp_magic
  23  *
  24  * this function must be called with even lengths, except
  25  * for the last fragment, which may be odd
  26  *
  27  * it's best to have buff aligned on a 32-bit boundary
  28  */
  29 extern unsigned int csum_partial (const unsigned char * buff, int len,
  30                                   unsigned int sum);
  31
  32 /*
  33  * the same as csum_partial, but copies from src while it
  34  * checksums
  35  *
  36  * here even more important to align src and dst on a 32-bit (or even
  37  * better 64-bit) boundary
  38  */
  39 extern unsigned csum_partial_copy (const char *src, char *dst, int len,
  40                                    unsigned sum);
  41
  42
  43 /*
  44  * the same as csum_partial_copy, but copies from user space.
  45  *
  46  * here even more important to align src and dst on a 32-bit (or even
  47  * better 64-bit) boundary
  48  */
  49 extern unsigned csum_partial_copy_from_user (const char *src, char *dst,
  50                                              int len, unsigned sum,
  51                                              int *csum_err);
  52
  53 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
  54         csum_partial_copy ((src), (dst), (len), (sum))
  55
  56 unsigned short ip_fast_csum (unsigned char *iph, unsigned int ihl);
  57
  58 /*
  59  *      Fold a partial checksum
  60  */
  61 static inline unsigned int csum_fold (unsigned long sum)
  62 {
  63         unsigned int result;
  64         /*
  65                                 %0              %1
  66               hsw %1, %0        H     L         L     H
  67               add %1, %0        H     L         H+L+C H+L
  68         */
  69         asm ("hsw %1, %0; add %1, %0" : "=&r" (result) : "r" (sum));
  70         return (~result) >> 16;
  71 }
  72
  73
  74 /*
  75  * computes the checksum of the TCP/UDP pseudo-header
  76  * returns a 16-bit checksum, already complemented
  77  */
  78 static inline unsigned int
  79 csum_tcpudp_nofold (unsigned long saddr, unsigned long daddr,
  80                     unsigned short len,
  81                     unsigned short proto, unsigned int sum)
  82 {
  83         int __carry;
  84         __asm__ ("add %2, %0;"
  85                  "setf c, %1;"
  86                  "add %1, %0;"
  87                  "add %3, %0;"
  88                  "setf c, %1;"
  89                  "add %1, %0;"
  90                  "add %4, %0;"
  91                  "setf c, %1;"
  92                  "add %1, %0"
  93                  : "=&r" (sum), "=&r" (__carry)
  94                  : "r" (daddr), "r" (saddr),
  95                  "r" (ntohs (len) + (proto << 8)),
  96                  "0" (sum));
  97         return sum;
  98 }
  99
 100 static inline unsigned short int
 101 csum_tcpudp_magic (unsigned long saddr, unsigned long daddr,
 102                    unsigned short len,
 103                    unsigned short proto, unsigned int sum)
 104 {
 105         return csum_fold (csum_tcpudp_nofold (saddr, daddr, len, proto, sum));
 106 }
 107
 108 /*
 109  * this routine is used for miscellaneous IP-like checksums, mainly
 110  * in icmp.c
 111  */
 112 extern unsigned short ip_compute_csum (const unsigned char * buff, int len);
 113
 114
 115 #endif /* __V850_CHECKSUM_H__ */