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1/*
2 * Network Checksum & Copy routine
3 *
4 * Copyright (C) 1999, 2003-2004 Hewlett-Packard Co
5 * Stephane Eranian <eranian@hpl.hp.com>
6 *
7 * Most of the code has been imported from Linux/Alpha
8 */
9
10#include <linux/module.h>
11#include <linux/types.h>
12#include <linux/string.h>
13
14#include <asm/uaccess.h>
15
16/*
17 * XXX Fixme: those 2 inlines are meant for debugging and will go away
18 */
19static inline unsigned
20short from64to16(unsigned long x)
21{
22 /* add up 32-bit words for 33 bits */
23 x = (x & 0xffffffff) + (x >> 32);
24 /* add up 16-bit and 17-bit words for 17+c bits */
25 x = (x & 0xffff) + (x >> 16);
26 /* add up 16-bit and 2-bit for 16+c bit */
27 x = (x & 0xffff) + (x >> 16);
28 /* add up carry.. */
29 x = (x & 0xffff) + (x >> 16);
30 return x;
31}
32
33static inline
34unsigned long do_csum_c(const unsigned char * buff, int len, unsigned int psum)
35{
36 int odd, count;
37 unsigned long result = (unsigned long)psum;
38
39 if (len <= 0)
40 goto out;
41 odd = 1 & (unsigned long) buff;
42 if (odd) {
43 result = *buff << 8;
44 len--;
45 buff++;
46 }
47 count = len >> 1; /* nr of 16-bit words.. */
48 if (count) {
49 if (2 & (unsigned long) buff) {
50 result += *(unsigned short *) buff;
51 count--;
52 len -= 2;
53 buff += 2;
54 }
55 count >>= 1; /* nr of 32-bit words.. */
56 if (count) {
57 if (4 & (unsigned long) buff) {
58 result += *(unsigned int *) buff;
59 count--;
60 len -= 4;
61 buff += 4;
62 }
63 count >>= 1; /* nr of 64-bit words.. */
64 if (count) {
65 unsigned long carry = 0;
66 do {
67 unsigned long w = *(unsigned long *) buff;
68 count--;
69 buff += 8;
70 result += carry;
71 result += w;
72 carry = (w > result);
73 } while (count);
74 result += carry;
75 result = (result & 0xffffffff) + (result >> 32);
76 }
77 if (len & 4) {
78 result += *(unsigned int *) buff;
79 buff += 4;
80 }
81 }
82 if (len & 2) {
83 result += *(unsigned short *) buff;
84 buff += 2;
85 }
86 }
87 if (len & 1)
88 result += *buff;
89
90 result = from64to16(result);
91
92 if (odd)
93 result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
94
95out:
96 return result;
97}
98
99/*
100 * XXX Fixme
101 *
102 * This is very ugly but temporary. THIS NEEDS SERIOUS ENHANCEMENTS.
103 * But it's very tricky to get right even in C.
104 */
105extern unsigned long do_csum(const unsigned char *, long);
106
107__wsum
108csum_partial_copy_from_user(const void __user *src, void *dst,
109 int len, __wsum psum, int *errp)
110{
111 unsigned long result;
112
113 /* XXX Fixme
114 * for now we separate the copy from checksum for obvious
115 * alignment difficulties. Look at the Alpha code and you'll be
116 * scared.
117 */
118
119 if (__copy_from_user(dst, src, len) != 0 && errp)
120 *errp = -EFAULT;
121
122 result = do_csum(dst, len);
123
124 /* add in old sum, and carry.. */
125 result += (__force u32)psum;
126 /* 32+c bits -> 32 bits */
127 result = (result & 0xffffffff) + (result >> 32);
128 return (__force __wsum)result;
129}
130
131EXPORT_SYMBOL(csum_partial_copy_from_user);
132
133__wsum
134csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
135{
136 return csum_partial_copy_from_user((__force const void __user *)src,
137 dst, len, sum, NULL);
138}
139
140EXPORT_SYMBOL(csum_partial_copy_nocheck);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Network Checksum & Copy routine
4 *
5 * Copyright (C) 1999, 2003-2004 Hewlett-Packard Co
6 * Stephane Eranian <eranian@hpl.hp.com>
7 *
8 * Most of the code has been imported from Linux/Alpha
9 */
10
11#include <linux/module.h>
12#include <linux/types.h>
13#include <linux/string.h>
14
15#include <net/checksum.h>
16
17/*
18 * XXX Fixme: those 2 inlines are meant for debugging and will go away
19 */
20static inline unsigned
21short from64to16(unsigned long x)
22{
23 /* add up 32-bit words for 33 bits */
24 x = (x & 0xffffffff) + (x >> 32);
25 /* add up 16-bit and 17-bit words for 17+c bits */
26 x = (x & 0xffff) + (x >> 16);
27 /* add up 16-bit and 2-bit for 16+c bit */
28 x = (x & 0xffff) + (x >> 16);
29 /* add up carry.. */
30 x = (x & 0xffff) + (x >> 16);
31 return x;
32}
33
34static inline
35unsigned long do_csum_c(const unsigned char * buff, int len, unsigned int psum)
36{
37 int odd, count;
38 unsigned long result = (unsigned long)psum;
39
40 if (len <= 0)
41 goto out;
42 odd = 1 & (unsigned long) buff;
43 if (odd) {
44 result = *buff << 8;
45 len--;
46 buff++;
47 }
48 count = len >> 1; /* nr of 16-bit words.. */
49 if (count) {
50 if (2 & (unsigned long) buff) {
51 result += *(unsigned short *) buff;
52 count--;
53 len -= 2;
54 buff += 2;
55 }
56 count >>= 1; /* nr of 32-bit words.. */
57 if (count) {
58 if (4 & (unsigned long) buff) {
59 result += *(unsigned int *) buff;
60 count--;
61 len -= 4;
62 buff += 4;
63 }
64 count >>= 1; /* nr of 64-bit words.. */
65 if (count) {
66 unsigned long carry = 0;
67 do {
68 unsigned long w = *(unsigned long *) buff;
69 count--;
70 buff += 8;
71 result += carry;
72 result += w;
73 carry = (w > result);
74 } while (count);
75 result += carry;
76 result = (result & 0xffffffff) + (result >> 32);
77 }
78 if (len & 4) {
79 result += *(unsigned int *) buff;
80 buff += 4;
81 }
82 }
83 if (len & 2) {
84 result += *(unsigned short *) buff;
85 buff += 2;
86 }
87 }
88 if (len & 1)
89 result += *buff;
90
91 result = from64to16(result);
92
93 if (odd)
94 result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
95
96out:
97 return result;
98}
99
100/*
101 * XXX Fixme
102 *
103 * This is very ugly but temporary. THIS NEEDS SERIOUS ENHANCEMENTS.
104 * But it's very tricky to get right even in C.
105 */
106__wsum
107csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
108{
109 memcpy(dst, src, len);
110 return csum_partial(dst, len, sum);
111}
112
113EXPORT_SYMBOL(csum_partial_copy_nocheck);