1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Checksumming functions for IP, TCP, UDP and so on
*
* Authors: Jorge Cwik, <jorge@laser.satlink.net>
* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
* Borrows very liberally from tcp.c and ip.c, see those
* files for more names.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _CHECKSUM_H
#define _CHECKSUM_H
#include <linux/errno.h>
#include <asm/types.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>
#include <asm/checksum.h>
#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
static inline
__wsum csum_and_copy_from_user (const void __user *src, void *dst,
int len, __wsum sum, int *err_ptr)
{
if (access_ok(VERIFY_READ, src, len))
return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
if (len)
*err_ptr = -EFAULT;
return sum;
}
#endif
#ifndef HAVE_CSUM_COPY_USER
static __inline__ __wsum csum_and_copy_to_user
(const void *src, void __user *dst, int len, __wsum sum, int *err_ptr)
{
sum = csum_partial(src, len, sum);
if (access_ok(VERIFY_WRITE, dst, len)) {
if (copy_to_user(dst, src, len) == 0)
return sum;
}
if (len)
*err_ptr = -EFAULT;
return (__force __wsum)-1; /* invalid checksum */
}
#endif
#ifndef HAVE_ARCH_CSUM_ADD
static inline __wsum csum_add(__wsum csum, __wsum addend)
{
u32 res = (__force u32)csum;
res += (__force u32)addend;
return (__force __wsum)(res + (res < (__force u32)addend));
}
#endif
static inline __wsum csum_sub(__wsum csum, __wsum addend)
{
return csum_add(csum, ~addend);
}
static inline __sum16 csum16_add(__sum16 csum, __be16 addend)
{
u16 res = (__force u16)csum;
res += (__force u16)addend;
return (__force __sum16)(res + (res < (__force u16)addend));
}
static inline __sum16 csum16_sub(__sum16 csum, __be16 addend)
{
return csum16_add(csum, ~addend);
}
static inline __wsum
csum_block_add(__wsum csum, __wsum csum2, int offset)
{
u32 sum = (__force u32)csum2;
/* rotate sum to align it with a 16b boundary */
if (offset & 1)
sum = ror32(sum, 8);
return csum_add(csum, (__force __wsum)sum);
}
static inline __wsum
csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len)
{
return csum_block_add(csum, csum2, offset);
}
static inline __wsum
csum_block_sub(__wsum csum, __wsum csum2, int offset)
{
return csum_block_add(csum, ~csum2, offset);
}
static inline __wsum csum_unfold(__sum16 n)
{
return (__force __wsum)n;
}
static inline __wsum csum_partial_ext(const void *buff, int len, __wsum sum)
{
return csum_partial(buff, len, sum);
}
#define CSUM_MANGLED_0 ((__force __sum16)0xffff)
static inline void csum_replace_by_diff(__sum16 *sum, __wsum diff)
{
*sum = csum_fold(csum_add(diff, ~csum_unfold(*sum)));
}
static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to)
{
__wsum tmp = csum_sub(~csum_unfold(*sum), (__force __wsum)from);
*sum = csum_fold(csum_add(tmp, (__force __wsum)to));
}
/* Implements RFC 1624 (Incremental Internet Checksum)
* 3. Discussion states :
* HC' = ~(~HC + ~m + m')
* m : old value of a 16bit field
* m' : new value of a 16bit field
*/
static inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new)
{
*sum = ~csum16_add(csum16_sub(~(*sum), old), new);
}
struct sk_buff;
void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
__be32 from, __be32 to, bool pseudohdr);
void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
const __be32 *from, const __be32 *to,
bool pseudohdr);
void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
__wsum diff, bool pseudohdr);
static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
__be16 from, __be16 to,
bool pseudohdr)
{
inet_proto_csum_replace4(sum, skb, (__force __be32)from,
(__force __be32)to, pseudohdr);
}
static inline __wsum remcsum_adjust(void *ptr, __wsum csum,
int start, int offset)
{
__sum16 *psum = (__sum16 *)(ptr + offset);
__wsum delta;
/* Subtract out checksum up to start */
csum = csum_sub(csum, csum_partial(ptr, start, 0));
/* Set derived checksum in packet */
delta = csum_sub((__force __wsum)csum_fold(csum),
(__force __wsum)*psum);
*psum = csum_fold(csum);
return delta;
}
static inline void remcsum_unadjust(__sum16 *psum, __wsum delta)
{
*psum = csum_fold(csum_sub(delta, *psum));
}
#endif
|
