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
186
187
188
|
#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
*/
unsigned int
csum_partial(const unsigned char * buff, int len, unsigned int sum);
/*
* csum_partial as an inline function
*/
extern inline unsigned int
csum_partial_inline(const unsigned char * buff, int len, unsigned int sum)
{
__asm__ __volatile__ (
" lr 2,%1\n" /* address in gpr 2 */
" lr 3,%2\n" /* length in gpr 3 */
"0: cksm %0,2\n" /* do checksum on longs */
" jo 0b\n"
: "+&d" (sum)
: "d" (buff), "d" (len)
: "cc", "2", "3" );
return sum;
}
/*
* the same as csum_partial, but copies from src while it
* checksums
*
* here even more important to align src and dst on a 32-bit (or even
* better 64-bit) boundary
*/
extern inline unsigned int
csum_partial_copy(const char *src, char *dst, int len,unsigned int sum)
{
memcpy(dst,src,len);
return csum_partial_inline(dst, len, 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
*/
extern inline unsigned int
csum_partial_copy_from_user(const char *src, char *dst,
int len, unsigned int sum, int *errp)
{
if (copy_from_user(dst, src, len)) {
*errp = -EFAULT;
memset(dst, 0, len);
return sum;
}
return csum_partial(dst, len, sum);
}
extern inline unsigned int
csum_partial_copy_nocheck (const char *src, char *dst, int len, unsigned int sum)
{
memcpy(dst,src,len);
return csum_partial_inline(dst, len, sum);
}
/*
* Fold a partial checksum without adding pseudo headers
*/
#if 1
unsigned short csum_fold(unsigned int sum);
#else
extern inline unsigned short
csum_fold(unsigned int sum)
{
__asm__ __volatile__ (
" sr 3,3\n" /* %0 = H*65536 + L */
" lr 2,%0\n" /* %0 = H L, R2/R3 = H L / 0 0 */
" srdl 2,16\n" /* %0 = H L, R2/R3 = 0 H / L 0 */
" alr 2,3\n" /* %0 = H L, R2/R3 = L H / L 0 */
" alr %0,2\n" /* %0 = H+L+C L+H */
" srl %0,16\n" /* %0 = H+L+C */
: "+&d" (sum) : : "cc", "2", "3");
return ((unsigned short) ~sum);
}
#endif
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries.
*
*/
extern inline unsigned short
ip_fast_csum(unsigned char *iph, unsigned int ihl)
{
unsigned long sum;
__asm__ __volatile__ (
" sr %0,%0\n" /* set sum to zero */
" lr 2,%1\n" /* address in gpr 2 */
" lr 3,%2\n" /* length in gpr 3 */
"0: cksm %0,2\n" /* do checksum on longs */
" jo 0b\n"
: "=&d" (sum)
: "d" (iph), "d" (ihl*4)
: "cc", "2", "3" );
return csum_fold(sum);
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 32-bit checksum
*/
extern inline unsigned int
csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
unsigned short len, unsigned short proto,
unsigned int sum)
{
__asm__ __volatile__ (
" sll %3,16\n"
" or %3,%4\n" /* newproto=proto<<16 in hiword, len in lowword */
" alr %1,%2\n" /* saddr+=daddr */
" brc 12,0f\n"
" ahi %1,1\n" /* add carry */
"0: alr %1,%3\n" /* add saddr+=newproto */
" brc 12,1f\n"
" ahi %1,1\n" /* add carry again */
"1: alr %0,%1\n" /* sum+=saddr */
" brc 12,2f\n"
" ahi %0,1\n" /* add carry again */
"2:"
: "+&d" (sum)
: "d" (saddr), "d" (daddr), "d" (proto), "d" (len)
: "cc" );
return sum;
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/
extern inline unsigned short int
csum_tcpudp_magic(unsigned long saddr, unsigned long daddr,
unsigned short len, unsigned short proto,
unsigned int 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
*/
extern inline unsigned short
ip_compute_csum(unsigned char * buff, int len)
{
return csum_fold(csum_partial(buff, len, 0));
}
#endif /* _S390_CHECKSUM_H */
|
