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
|
#ifndef _S390_CHECKSUM_H
#define _S390_CHECKSUM_H
/*
* include/asm-s390/checksum.h
* S390 fast network checksum routines
* see also arch/S390/lib/checksum.c
*
* S390 version
* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Ulrich Hild (first version)
* Martin Schwidefsky (heavily optimized CKSM version)
* D.J. Barrow (third attempt)
*/
#include <asm/uaccess.h>
/*
* computes the checksum of a memory block at buff, length len,
* and adds in "sum" (32-bit)
*
* returns a 32-bit number suitable for feeding into itself
* or csum_tcpudp_magic
*
* this function must be called with even lengths, except
* for the last fragment, which may be odd
*
* it's best to have buff aligned on a 32-bit boundary
*/
static inline __wsum
csum_partial(const void *buff, int len, __wsum sum)
{
register unsigned long reg2 asm("2") = (unsigned long) buff;
register unsigned long reg3 asm("3") = (unsigned long) len;
asm volatile(
"0: cksm %0,%1\n" /* do checksum on longs */
" jo 0b\n"
: "+d" (sum), "+d" (reg2), "+d" (reg3) : : "cc", "memory");
return sum;
}
/*
* the same as csum_partial_copy, but copies from user space.
*
* here even more important to align src and dst on a 32-bit (or even
* better 64-bit) boundary
*
* Copy from userspace and compute checksum. If we catch an exception
* then zero the rest of the buffer.
*/
static inline __wsum
csum_partial_copy_from_user(const void __user *src, void *dst,
int len, __wsum sum,
int *err_ptr)
{
int missing;
missing = copy_from_user(dst, src, len);
if (missing) {
memset(dst + len - missing, 0, missing);
*err_ptr = -EFAULT;
}
return csum_partial(dst, len, sum);
}
static inline __wsum
csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum)
{
memcpy(dst,src,len);
return csum_partial(dst, len, sum);
}
/*
* Fold a partial checksum without adding pseudo headers
*/
static inline __sum16 csum_fold(__wsum sum)
{
u32 csum = (__force u32) sum;
csum += (csum >> 16) + (csum << 16);
csum >>= 16;
return (__force __sum16) ~csum;
}
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries.
*
*/
static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
{
return csum_fold(csum_partial(iph, ihl*4, 0));
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 32-bit checksum
*/
static inline __wsum
csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
unsigned short len, unsigned short proto,
__wsum sum)
{
__u32 csum = (__force __u32)sum;
csum += (__force __u32)saddr;
if (csum < (__force __u32)saddr)
csum++;
csum += (__force __u32)daddr;
if (csum < (__force __u32)daddr)
csum++;
csum += len + proto;
if (csum < len + proto)
csum++;
return (__force __wsum)csum;
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/
static inline __sum16
csum_tcpudp_magic(__be32 saddr, __be32 daddr,
unsigned short len, unsigned short proto,
__wsum sum)
{
return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
}
/*
* this routine is used for miscellaneous IP-like checksums, mainly
* in icmp.c
*/
static inline __sum16 ip_compute_csum(const void *buff, int len)
{
return csum_fold(csum_partial(buff, len, 0));
}
#endif /* _S390_CHECKSUM_H */
|
