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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Al Viro56649d52006-11-14 21:23:59 -080030__wsum csum_and_copy_from_user (const void __user *src, void *dst,
31 int len, __wsum sum, int *err_ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070032{
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
Al Viro56649d52006-11-14 21:23:59 -080044static __inline__ __wsum csum_and_copy_to_user
45(const void *src, void __user *dst, int len, __wsum sum, int *err_ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070046{
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
Al Viro56649d52006-11-14 21:23:59 -080056 return (__force __wsum)-1; /* invalid checksum */
Linus Torvalds1da177e2005-04-16 15:20:36 -070057}
58#endif
59
Al Viro56649d52006-11-14 21:23:59 -080060static inline __wsum csum_add(__wsum csum, __wsum addend)
Linus Torvalds1da177e2005-04-16 15:20:36 -070061{
Al Viro56649d52006-11-14 21:23:59 -080062 u32 res = (__force u32)csum;
63 res += (__force u32)addend;
64 return (__force __wsum)(res + (res < (__force u32)addend));
Linus Torvalds1da177e2005-04-16 15:20:36 -070065}
66
Al Viro56649d52006-11-14 21:23:59 -080067static inline __wsum csum_sub(__wsum csum, __wsum addend)
Linus Torvalds1da177e2005-04-16 15:20:36 -070068{
69 return csum_add(csum, ~addend);
70}
71
Al Viro56649d52006-11-14 21:23:59 -080072static inline __wsum
73csum_block_add(__wsum csum, __wsum csum2, int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -070074{
Al Viro56649d52006-11-14 21:23:59 -080075 u32 sum = (__force u32)csum2;
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 if (offset&1)
Al Viro56649d52006-11-14 21:23:59 -080077 sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
78 return csum_add(csum, (__force __wsum)sum);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079}
80
Al Viro56649d52006-11-14 21:23:59 -080081static inline __wsum
82csum_block_sub(__wsum csum, __wsum csum2, int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -070083{
Al Viro56649d52006-11-14 21:23:59 -080084 u32 sum = (__force u32)csum2;
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 if (offset&1)
Al Viro56649d52006-11-14 21:23:59 -080086 sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
87 return csum_sub(csum, (__force __wsum)sum);
88}
89
90static inline __wsum csum_unfold(__sum16 n)
91{
92 return (__force __wsum)n;
Linus Torvalds1da177e2005-04-16 15:20:36 -070093}
94
Al Virof6ab0282006-11-16 02:36:50 -080095#define CSUM_MANGLED_0 ((__force __sum16)0xffff)
Patrick McHardya99a00c2007-11-30 01:14:30 +110096
97static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to)
98{
99 __be32 diff[] = { ~from, to };
100
101 *sum = csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum_unfold(*sum)));
102}
103
104static inline void csum_replace2(__sum16 *sum, __be16 from, __be16 to)
105{
106 csum_replace4(sum, (__force __be32)from, (__force __be32)to);
107}
108
109struct sk_buff;
110extern void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
111 __be32 from, __be32 to, int pseudohdr);
112
113static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
114 __be16 from, __be16 to,
115 int pseudohdr)
116{
117 inet_proto_csum_replace4(sum, skb, (__force __be32)from,
118 (__force __be32)to, pseudohdr);
119}
120
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121#endif