csum_partial_copy.c revision 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 
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 */
30unsigned int
31csum_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}
39EXPORT_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 */
45unsigned int
46csum_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}
60EXPORT_SYMBOL(csum_partial_copy_from_user);
61