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 <linux/kernel.h>
  10 #include <linux/types.h>
  11 #include <asm/byteorder.h>
  12 #include <asm/string.h>
  13 #include <asm/uaccess.h>
  14 #include <net/checksum.h>
  15
  16 /*
  17  * copy while checksumming, otherwise like csum_partial
  18  */
  19 unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst,
  20         int len, unsigned int sum)
  21 {
  22         /*
  23          * It's 2:30 am and I don't feel like doing it real ...
  24          * This is lots slower than the real thing (tm)
  25          */
  26         sum = csum_partial(src, len, sum);
  27         memcpy(dst, src, len);
  28
  29         return sum;
  30 }
  31
  32 /*
  33  * Copy from userspace and compute checksum.  If we catch an exception
  34  * then zero the rest of the buffer.
  35  */
  36 unsigned int csum_partial_copy_from_user (const unsigned char *src, unsigned char *dst,
  37         int len, unsigned int sum, int *err_ptr)
  38 {
  39         int missing;
  40
  41         might_sleep();
  42         missing = copy_from_user(dst, src, len);
  43         if (missing) {
  44                 memset(dst + len - missing, 0, missing);
  45                 *err_ptr = -EFAULT;
  46         }
  47
  48         return csum_partial(dst, len, sum);
  49 }