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Linux kernel mirror (for testing)
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kernel
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linux
1/*
2 * Copyright 2004-2009 Analog Devices Inc.
3 * akbar.hussain@lineo.com
4 *
5 * Licensed under the GPL-2 or later.
6 */
7
8#ifndef _BFIN_CHECKSUM_H
9#define _BFIN_CHECKSUM_H
10
11/*
12 * computes the checksum of a memory block at buff, length len,
13 * and adds in "sum" (32-bit)
14 *
15 * returns a 32-bit number suitable for feeding into itself
16 * or csum_tcpudp_magic
17 *
18 * this function must be called with even lengths, except
19 * for the last fragment, which may be odd
20 *
21 * it's best to have buff aligned on a 32-bit boundary
22 */
23__wsum csum_partial(const void *buff, int len, __wsum sum);
24
25/*
26 * the same as csum_partial, but copies from src while it
27 * checksums
28 *
29 * here even more important to align src and dst on a 32-bit (or even
30 * better 64-bit) boundary
31 */
32
33__wsum csum_partial_copy(const void *src, void *dst,
34 int len, __wsum sum);
35
36/*
37 * the same as csum_partial_copy, but copies from user space.
38 *
39 * here even more important to align src and dst on a 32-bit (or even
40 * better 64-bit) boundary
41 */
42
43extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
44 int len, __wsum sum, int *csum_err);
45
46#define csum_partial_copy_nocheck(src, dst, len, sum) \
47 csum_partial_copy((src), (dst), (len), (sum))
48
49__sum16 ip_fast_csum(unsigned char *iph, unsigned int ihl);
50
51/*
52 * Fold a partial checksum
53 */
54
55static inline __sum16 csum_fold(__wsum sum)
56{
57 while (sum >> 16)
58 sum = (sum & 0xffff) + (sum >> 16);
59 return ((~(sum << 16)) >> 16);
60}
61
62/*
63 * computes the checksum of the TCP/UDP pseudo-header
64 * returns a 16-bit checksum, already complemented
65 */
66
67static inline __wsum
68csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
69 unsigned short proto, __wsum sum)
70{
71 unsigned int carry;
72
73 __asm__ ("%0 = %0 + %2;\n\t"
74 "CC = AC0;\n\t"
75 "%1 = CC;\n\t"
76 "%0 = %0 + %1;\n\t"
77 "%0 = %0 + %3;\n\t"
78 "CC = AC0;\n\t"
79 "%1 = CC;\n\t"
80 "%0 = %0 + %1;\n\t"
81 "%0 = %0 + %4;\n\t"
82 "CC = AC0;\n\t"
83 "%1 = CC;\n\t"
84 "%0 = %0 + %1;\n\t"
85 : "=d" (sum), "=&d" (carry)
86 : "d" (daddr), "d" (saddr), "d" ((len + proto) << 8), "0"(sum)
87 : "CC");
88
89 return (sum);
90}
91
92static inline __sum16
93csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
94 unsigned short proto, __wsum sum)
95{
96 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
97}
98
99/*
100 * this routine is used for miscellaneous IP-like checksums, mainly
101 * in icmp.c
102 */
103
104extern __sum16 ip_compute_csum(const void *buff, int len);
105
106#endif /* _BFIN_CHECKSUM_H */