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
|
/*
* arch/arm/include/asm/checksum.h
*
* IP checksum routines
*
* Copyright (C) Original authors of ../asm-i386/checksum.h
* Copyright (C) 1996-1999 Russell King
*/
#ifndef __ASM_ARM_CHECKSUM_H
#define __ASM_ARM_CHECKSUM_H
#include <linux/in6.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
*/
__wsum csum_partial(const void *buff, int len, __wsum sum);
/*
* the same as csum_partial, but copies from src while it
* checksums, and handles user-space pointer exceptions correctly, when needed.
*
* here even more important to align src and dst on a 32-bit (or even
* better 64-bit) boundary
*/
__wsum
csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
__wsum
csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr);
/*
* Fold a partial checksum without adding pseudo headers
*/
static inline __sum16 csum_fold(__wsum sum)
{
__asm__(
"add %0, %1, %1, ror #16 @ csum_fold"
: "=r" (sum)
: "r" (sum)
: "cc");
return (__force __sum16)(~(__force u32)sum >> 16);
}
/*
* 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)
{
unsigned int tmp1;
__wsum sum;
__asm__ __volatile__(
"ldr %0, [%1], #4 @ ip_fast_csum \n\
ldr %3, [%1], #4 \n\
sub %2, %2, #5 \n\
adds %0, %0, %3 \n\
ldr %3, [%1], #4 \n\
adcs %0, %0, %3 \n\
ldr %3, [%1], #4 \n\
1: adcs %0, %0, %3 \n\
ldr %3, [%1], #4 \n\
tst %2, #15 @ do this carefully \n\
subne %2, %2, #1 @ without destroying \n\
bne 1b @ the carry flag \n\
adcs %0, %0, %3 \n\
adc %0, %0, #0"
: "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1)
: "1" (iph), "2" (ihl)
: "cc", "memory");
return csum_fold(sum);
}
static inline __wsum
csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
__u8 proto, __wsum sum)
{
u32 lenprot = len + proto;
if (__builtin_constant_p(sum) && sum == 0) {
__asm__(
"adds %0, %1, %2 @ csum_tcpudp_nofold0 \n\t"
#ifdef __ARMEB__
"adcs %0, %0, %3 \n\t"
#else
"adcs %0, %0, %3, ror #8 \n\t"
#endif
"adc %0, %0, #0"
: "=&r" (sum)
: "r" (daddr), "r" (saddr), "r" (lenprot)
: "cc");
} else {
__asm__(
"adds %0, %1, %2 @ csum_tcpudp_nofold \n\t"
"adcs %0, %0, %3 \n\t"
#ifdef __ARMEB__
"adcs %0, %0, %4 \n\t"
#else
"adcs %0, %0, %4, ror #8 \n\t"
#endif
"adc %0, %0, #0"
: "=&r"(sum)
: "r" (sum), "r" (daddr), "r" (saddr), "r" (lenprot)
: "cc");
}
return sum;
}
/*
* 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, __u32 len,
__u8 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));
}
#define _HAVE_ARCH_IPV6_CSUM
extern __wsum
__csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len,
__be32 proto, __wsum sum);
static inline __sum16
csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
__u32 len, __u8 proto, __wsum sum)
{
return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len),
htonl(proto), sum));
}
#endif
|
