tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 * Checksumming functions for IP, TCP, UDP and so on
7 *
8 * Authors: Jorge Cwik, <jorge@laser.satlink.net>
9 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
10 * Borrows very liberally from tcp.c and ip.c, see those
11 * files for more names.
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
17 */
18
19#ifndef _CHECKSUM_H
20#define _CHECKSUM_H
21
22#include <linux/errno.h>
23#include <asm/types.h>
24#include <asm/byteorder.h>
25#include <asm/uaccess.h>
26#include <asm/checksum.h>
27
28#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
29static inline
30unsigned int csum_and_copy_from_user (const unsigned char __user *src, unsigned char *dst,
31 int len, int sum, int *err_ptr)
32{
33 if (access_ok(VERIFY_READ, src, len))
34 return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
35
36 if (len)
37 *err_ptr = -EFAULT;
38
39 return sum;
40}
41#endif
42
43#ifndef HAVE_CSUM_COPY_USER
44static __inline__ unsigned int csum_and_copy_to_user
45(const unsigned char *src, unsigned char __user *dst, int len, unsigned int sum, int *err_ptr)
46{
47 sum = csum_partial(src, len, sum);
48
49 if (access_ok(VERIFY_WRITE, dst, len)) {
50 if (copy_to_user(dst, src, len) == 0)
51 return sum;
52 }
53 if (len)
54 *err_ptr = -EFAULT;
55
56 return -1; /* invalid checksum */
57}
58#endif
59
60static inline unsigned int csum_add(unsigned int csum, unsigned int addend)
61{
62 csum += addend;
63 return csum + (csum < addend);
64}
65
66static inline unsigned int csum_sub(unsigned int csum, unsigned int addend)
67{
68 return csum_add(csum, ~addend);
69}
70
71static inline unsigned int
72csum_block_add(unsigned int csum, unsigned int csum2, int offset)
73{
74 if (offset&1)
75 csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);
76 return csum_add(csum, csum2);
77}
78
79static inline unsigned int
80csum_block_sub(unsigned int csum, unsigned int csum2, int offset)
81{
82 if (offset&1)
83 csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);
84 return csum_sub(csum, csum2);
85}
86
87#endif