arch/m32r/lib/csum_partial_copy.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              M32R specific IP/TCP/UDP checksumming routines
   7  *              (Some code taken from MIPS architecture)
   8  *
   9  * This file is subject to the terms and conditions of the GNU General Public
  10  * License.  See the file "COPYING" in the main directory of this archive
  11  * for more details.
  12  *
  13  * Copyright (C) 1994, 1995  Waldorf Electronics GmbH
  14  * Copyright (C) 1998, 1999  Ralf Baechle
  15  * Copyright (C) 2001-2005  Hiroyuki Kondo, Hirokazu Takata
  16  *
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/types.h>
  21
  22 #include <net/checksum.h>
  23 #include <asm/byteorder.h>
  24 #include <asm/string.h>
  25 #include <asm/uaccess.h>
  26
  27 /*
  28  * Copy while checksumming, otherwise like csum_partial
  29  */
  30 unsigned int
  31 csum_partial_copy_nocheck (const unsigned char *src, unsigned char *dst,
  32                            int len, unsigned int sum)
  33 {
  34         sum = csum_partial(src, len, sum);
  35         memcpy(dst, src, len);
  36
  37         return sum;
  38 }
  39 EXPORT_SYMBOL(csum_partial_copy_nocheck);
  40
  41 /*
  42  * Copy from userspace and compute checksum.  If we catch an exception
  43  * then zero the rest of the buffer.
  44  */
  45 unsigned int
  46 csum_partial_copy_from_user (const unsigned char __user *src,
  47                              unsigned char *dst,
  48                              int len, unsigned int sum, int *err_ptr)
  49 {
  50         int missing;
  51
  52         missing = copy_from_user(dst, src, len);
  53         if (missing) {
  54                 memset(dst + len - missing, 0, missing);
  55                 *err_ptr = -EFAULT;
  56         }
  57
  58         return csum_partial(dst, len-missing, sum);
  59 }
  60 EXPORT_SYMBOL(csum_partial_copy_from_user);