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  *              MIPS specific IP/TCP/UDP checksumming routines
   7  *
   8  * Authors:     Ralf Baechle, <ralf@waldorf-gmbh.de>
   9  *              Lots of code moved from tcp.c and ip.c; see those files
  10  *              for more names.
  11  *
  12  *              This program is free software; you can redistribute it and/or
  13  *              modify it under the terms of the GNU General Public License
  14  *              as published by the Free Software Foundation; either version
  15  *              2 of the License, or (at your option) any later version.
  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 csum_partial_copy_nocheck (const char *src, char *dst,
  31                                         int len, unsigned int sum)
  32 {
  33         sum = csum_partial(src, len, sum);
  34         memcpy(dst, src, len);
  35
  36         return sum;
  37 }
  38 EXPORT_SYMBOL(csum_partial_copy_nocheck);
  39
  40 /*
  41  * Copy from userspace and compute checksum.  If we catch an exception
  42  * then zero the rest of the buffer.
  43  */
  44 unsigned int csum_partial_copy_from_user (const char __user *src, char *dst,
  45                                           int len, unsigned int sum,
  46                                           int *err_ptr)
  47 {
  48         int missing;
  49
  50         missing = copy_from_user(dst, src, len);
  51         if (missing) {
  52                 memset(dst + len - missing, 0, missing);
  53                 *err_ptr = -EFAULT;
  54         }
  55
  56         return csum_partial(dst, len-missing, sum);
  57 }
  58 EXPORT_SYMBOL(csum_partial_copy_from_user);