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Linux kernel mirror (for testing)
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linux
1#ifndef _BFIN_CHECKSUM_H
2#define _BFIN_CHECKSUM_H
3
4/*
5 * MODIFIED FOR BFIN April 30, 2001 akbar.hussain@lineo.com
6 *
7 * computes the checksum of a memory block at buff, length len,
8 * and adds in "sum" (32-bit)
9 *
10 * returns a 32-bit number suitable for feeding into itself
11 * or csum_tcpudp_magic
12 *
13 * this function must be called with even lengths, except
14 * for the last fragment, which may be odd
15 *
16 * it's best to have buff aligned on a 32-bit boundary
17 */
18__wsum csum_partial(const void *buff, int len, __wsum sum);
19
20/*
21 * the same as csum_partial, but copies from src while it
22 * checksums
23 *
24 * here even more important to align src and dst on a 32-bit (or even
25 * better 64-bit) boundary
26 */
27
28__wsum csum_partial_copy(const void *src, void *dst,
29 int len, __wsum sum);
30
31/*
32 * the same as csum_partial_copy, but copies from user space.
33 *
34 * here even more important to align src and dst on a 32-bit (or even
35 * better 64-bit) boundary
36 */
37
38extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
39 int len, __wsum sum, int *csum_err);
40
41#define csum_partial_copy_nocheck(src, dst, len, sum) \
42 csum_partial_copy((src), (dst), (len), (sum))
43
44__sum16 ip_fast_csum(unsigned char *iph, unsigned int ihl);
45
46/*
47 * Fold a partial checksum
48 */
49
50static inline __sum16 csum_fold(__wsum sum)
51{
52 while (sum >> 16)
53 sum = (sum & 0xffff) + (sum >> 16);
54 return ((~(sum << 16)) >> 16);
55}
56
57/*
58 * computes the checksum of the TCP/UDP pseudo-header
59 * returns a 16-bit checksum, already complemented
60 */
61
62static inline __wsum
63csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
64 unsigned short proto, __wsum sum)
65{
66 unsigned int carry;
67
68 __asm__ ("%0 = %0 + %2;\n\t"
69 "CC = AC0;\n\t"
70 "%1 = CC;\n\t"
71 "%0 = %0 + %1;\n\t"
72 "%0 = %0 + %3;\n\t"
73 "CC = AC0;\n\t"
74 "%1 = CC;\n\t"
75 "%0 = %0 + %1;\n\t"
76 "%0 = %0 + %4;\n\t"
77 "CC = AC0;\n\t"
78 "%1 = CC;\n\t"
79 "%0 = %0 + %1;\n\t"
80 : "=d" (sum), "=&d" (carry)
81 : "d" (daddr), "d" (saddr), "d" ((len + proto) << 8), "0"(sum)
82 : "CC");
83
84 return (sum);
85}
86
87static inline __sum16
88csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
89 unsigned short proto, __wsum sum)
90{
91 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
92}
93
94/*
95 * this routine is used for miscellaneous IP-like checksums, mainly
96 * in icmp.c
97 */
98
99extern __sum16 ip_compute_csum(const void *buff, int len);
100
101#endif /* _BFIN_CHECKSUM_H */