arch/mips/lib/csum_partial_copy.c

   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) 1994, 1995 Waldorf Electronics GmbH
   7  * Copyright (C) 1998, 1999 Ralf Baechle
   8  */
   9 #include <net/checksum.h>
  10 #include <linux/types.h>
  11 #include <asm/byteorder.h>
  12 #include <asm/string.h>
  13 #include <asm/uaccess.h>
  14
  15 /*
  16  * copy while checksumming, otherwise like csum_partial
  17  */
  18 unsigned int csum_partial_copy_nocheck(const char *src, char *dst,
  19         int len, unsigned int sum)
  20 {
  21         /*
  22          * It's 2:30 am and I don't feel like doing it real ...
  23          * This is lots slower than the real thing (tm)
  24          */
  25         sum = csum_partial(src, len, sum);
  26         memcpy(dst, src, len);
  27
  28         return sum;
  29 }
  30
  31 /*
  32  * Copy from userspace and compute checksum.  If we catch an exception
  33  * then zero the rest of the buffer.
  34  */
  35 unsigned int csum_partial_copy_from_user (const char *src, char *dst,
  36         int len, unsigned int sum, int *err_ptr)
  37 {
  38         int missing;
  39
  40         missing = copy_from_user(dst, src, len);
  41         if (missing) {
  42                 memset(dst + len - missing, 0, missing);
  43                 *err_ptr = -EFAULT;
  44         }
  45
  46         return csum_partial(dst, len, sum);
  47 }