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35#include <linux/export.h>
36#include <net/checksum.h>
37
38#include <asm/byteorder.h>
39
40#ifndef do_csum
41static inline unsigned short from32to16(unsigned int x)
42{
43
44 x = (x & 0xffff) + (x >> 16);
45
46 x = (x & 0xffff) + (x >> 16);
47 return x;
48}
49
50static unsigned int do_csum(const unsigned char *buff, int len)
51{
52 int odd;
53 unsigned int result = 0;
54
55 if (len <= 0)
56 goto out;
57 odd = 1 & (unsigned long) buff;
58 if (odd) {
59#ifdef __LITTLE_ENDIAN
60 result += (*buff << 8);
61#else
62 result = *buff;
63#endif
64 len--;
65 buff++;
66 }
67 if (len >= 2) {
68 if (2 & (unsigned long) buff) {
69 result += *(unsigned short *) buff;
70 len -= 2;
71 buff += 2;
72 }
73 if (len >= 4) {
74 const unsigned char *end = buff + ((unsigned)len & ~3);
75 unsigned int carry = 0;
76 do {
77 unsigned int w = *(unsigned int *) buff;
78 buff += 4;
79 result += carry;
80 result += w;
81 carry = (w > result);
82 } while (buff < end);
83 result += carry;
84 result = (result & 0xffff) + (result >> 16);
85 }
86 if (len & 2) {
87 result += *(unsigned short *) buff;
88 buff += 2;
89 }
90 }
91 if (len & 1)
92#ifdef __LITTLE_ENDIAN
93 result += *buff;
94#else
95 result += (*buff << 8);
96#endif
97 result = from32to16(result);
98 if (odd)
99 result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
100out:
101 return result;
102}
103#endif
104
105
106
107
108
109__sum16 ip_fast_csum(const void *iph, unsigned int ihl)
110{
111 return (__force __sum16)~do_csum(iph, ihl*4);
112}
113EXPORT_SYMBOL(ip_fast_csum);
114
115
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117
118
119
120
121
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123
124
125
126
127__wsum csum_partial(const void *buff, int len, __wsum wsum)
128{
129 unsigned int sum = (__force unsigned int)wsum;
130 unsigned int result = do_csum(buff, len);
131
132
133 result += sum;
134 if (sum > result)
135 result += 1;
136 return (__force __wsum)result;
137}
138EXPORT_SYMBOL(csum_partial);
139
140
141
142
143
144__sum16 ip_compute_csum(const void *buff, int len)
145{
146 return (__force __sum16)~do_csum(buff, len);
147}
148EXPORT_SYMBOL(ip_compute_csum);
149
150
151
152
153__wsum
154csum_partial_copy_from_user(const void __user *src, void *dst, int len,
155 __wsum sum, int *csum_err)
156{
157 int missing;
158
159 missing = __copy_from_user(dst, src, len);
160 if (missing) {
161 memset(dst + len - missing, 0, missing);
162 *csum_err = -EFAULT;
163 } else
164 *csum_err = 0;
165
166 return csum_partial(dst, len, sum);
167}
168EXPORT_SYMBOL(csum_partial_copy_from_user);
169
170
171
172
173__wsum
174csum_partial_copy(const void *src, void *dst, int len, __wsum sum)
175{
176 memcpy(dst, src, len);
177 return csum_partial(dst, len, sum);
178}
179EXPORT_SYMBOL(csum_partial_copy);
180
181#ifndef csum_tcpudp_nofold
182__wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
183 unsigned short len,
184 unsigned short proto,
185 __wsum sum)
186{
187 unsigned long long s = (__force u32)sum;
188
189 s += (__force u32)saddr;
190 s += (__force u32)daddr;
191#ifdef __BIG_ENDIAN
192 s += proto + len;
193#else
194 s += (proto + len) << 8;
195#endif
196 s += (s >> 32);
197 return (__force __wsum)s;
198}
199EXPORT_SYMBOL(csum_tcpudp_nofold);
200#endif
201