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1da177e4 LT |
1 | #ifndef _PPC64_CHECKSUM_H |
2 | #define _PPC64_CHECKSUM_H | |
3 | ||
4 | /* | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License | |
7 | * as published by the Free Software Foundation; either version | |
8 | * 2 of the License, or (at your option) any later version. | |
9 | */ | |
10 | ||
11 | /* | |
12 | * This is a version of ip_compute_csum() optimized for IP headers, | |
13 | * which always checksum on 4 octet boundaries. ihl is the number | |
14 | * of 32-bit words and is always >= 5. | |
15 | */ | |
16 | extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl); | |
17 | ||
18 | /* | |
19 | * computes the checksum of the TCP/UDP pseudo-header | |
20 | * returns a 16-bit checksum, already complemented | |
21 | */ | |
22 | extern unsigned short csum_tcpudp_magic(unsigned long saddr, | |
23 | unsigned long daddr, | |
24 | unsigned short len, | |
25 | unsigned short proto, | |
26 | unsigned int sum); | |
27 | ||
28 | /* | |
29 | * computes the checksum of a memory block at buff, length len, | |
30 | * and adds in "sum" (32-bit) | |
31 | * | |
32 | * returns a 32-bit number suitable for feeding into itself | |
33 | * or csum_tcpudp_magic | |
34 | * | |
35 | * this function must be called with even lengths, except | |
36 | * for the last fragment, which may be odd | |
37 | * | |
38 | * it's best to have buff aligned on a 32-bit boundary | |
39 | */ | |
40 | extern unsigned int csum_partial(const unsigned char * buff, int len, | |
41 | unsigned int sum); | |
42 | ||
43 | /* | |
44 | * the same as csum_partial, but copies from src to dst while it | |
45 | * checksums | |
46 | */ | |
47 | extern unsigned int csum_partial_copy_generic(const char *src, char *dst, | |
48 | int len, unsigned int sum, | |
49 | int *src_err, int *dst_err); | |
50 | /* | |
51 | * the same as csum_partial, but copies from src to dst while it | |
52 | * checksums. | |
53 | */ | |
54 | ||
55 | unsigned int csum_partial_copy_nocheck(const char *src, | |
56 | char *dst, | |
57 | int len, | |
58 | unsigned int sum); | |
59 | ||
60 | /* | |
61 | * turns a 32-bit partial checksum (e.g. from csum_partial) into a | |
62 | * 1's complement 16-bit checksum. | |
63 | */ | |
64 | static inline unsigned int csum_fold(unsigned int sum) | |
65 | { | |
66 | unsigned int tmp; | |
67 | ||
68 | /* swap the two 16-bit halves of sum */ | |
69 | __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum)); | |
70 | /* if there is a carry from adding the two 16-bit halves, | |
71 | it will carry from the lower half into the upper half, | |
72 | giving us the correct sum in the upper half. */ | |
73 | sum = ~(sum + tmp) >> 16; | |
74 | return sum; | |
75 | } | |
76 | ||
77 | /* | |
78 | * this routine is used for miscellaneous IP-like checksums, mainly | |
79 | * in icmp.c | |
80 | */ | |
81 | static inline unsigned short ip_compute_csum(unsigned char * buff, int len) | |
82 | { | |
83 | return csum_fold(csum_partial(buff, len, 0)); | |
84 | } | |
85 | ||
86 | #define csum_partial_copy_from_user(src, dst, len, sum, errp) \ | |
87 | csum_partial_copy_generic((src), (dst), (len), (sum), (errp), NULL) | |
88 | ||
89 | #define csum_partial_copy_nocheck(src, dst, len, sum) \ | |
90 | csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL) | |
91 | ||
92 | static inline u32 csum_tcpudp_nofold(u32 saddr, | |
93 | u32 daddr, | |
94 | unsigned short len, | |
95 | unsigned short proto, | |
96 | unsigned int sum) | |
97 | { | |
98 | unsigned long s = sum; | |
99 | ||
100 | s += saddr; | |
101 | s += daddr; | |
102 | s += (proto << 16) + len; | |
103 | s += (s >> 32); | |
104 | return (u32) s; | |
105 | } | |
106 | ||
107 | #endif |