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1da177e4 LT |
1 | /* |
2 | * INET An implementation of the TCP/IP protocol suite for the LINUX | |
3 | * operating system. INET is implemented using the BSD Socket | |
4 | * interface as the means of communication with the user level. | |
5 | * | |
6 | * Checksumming functions for IP, TCP, UDP and so on | |
7 | * | |
8 | * Authors: Jorge Cwik, <jorge@laser.satlink.net> | |
9 | * Arnt Gulbrandsen, <agulbra@nvg.unit.no> | |
10 | * Borrows very liberally from tcp.c and ip.c, see those | |
11 | * files for more names. | |
12 | * | |
13 | * This program is free software; you can redistribute it and/or | |
14 | * modify it under the terms of the GNU General Public License | |
15 | * as published by the Free Software Foundation; either version | |
16 | * 2 of the License, or (at your option) any later version. | |
17 | */ | |
18 | ||
19 | #ifndef _CHECKSUM_H | |
20 | #define _CHECKSUM_H | |
21 | ||
22 | #include <linux/errno.h> | |
23 | #include <asm/types.h> | |
24 | #include <asm/byteorder.h> | |
25 | #include <asm/uaccess.h> | |
26 | #include <asm/checksum.h> | |
27 | ||
28 | #ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER | |
29 | static inline | |
56649d5d AV |
30 | __wsum csum_and_copy_from_user (const void __user *src, void *dst, |
31 | int len, __wsum sum, int *err_ptr) | |
1da177e4 LT |
32 | { |
33 | if (access_ok(VERIFY_READ, src, len)) | |
34 | return csum_partial_copy_from_user(src, dst, len, sum, err_ptr); | |
35 | ||
36 | if (len) | |
37 | *err_ptr = -EFAULT; | |
38 | ||
39 | return sum; | |
40 | } | |
41 | #endif | |
42 | ||
43 | #ifndef HAVE_CSUM_COPY_USER | |
56649d5d AV |
44 | static __inline__ __wsum csum_and_copy_to_user |
45 | (const void *src, void __user *dst, int len, __wsum sum, int *err_ptr) | |
1da177e4 LT |
46 | { |
47 | sum = csum_partial(src, len, sum); | |
48 | ||
49 | if (access_ok(VERIFY_WRITE, dst, len)) { | |
50 | if (copy_to_user(dst, src, len) == 0) | |
51 | return sum; | |
52 | } | |
53 | if (len) | |
54 | *err_ptr = -EFAULT; | |
55 | ||
56649d5d | 56 | return (__force __wsum)-1; /* invalid checksum */ |
1da177e4 LT |
57 | } |
58 | #endif | |
59 | ||
56649d5d | 60 | static inline __wsum csum_add(__wsum csum, __wsum addend) |
1da177e4 | 61 | { |
56649d5d AV |
62 | u32 res = (__force u32)csum; |
63 | res += (__force u32)addend; | |
64 | return (__force __wsum)(res + (res < (__force u32)addend)); | |
1da177e4 LT |
65 | } |
66 | ||
56649d5d | 67 | static inline __wsum csum_sub(__wsum csum, __wsum addend) |
1da177e4 LT |
68 | { |
69 | return csum_add(csum, ~addend); | |
70 | } | |
71 | ||
99f0b958 ED |
72 | static inline __sum16 csum16_add(__sum16 csum, __be16 addend) |
73 | { | |
74 | u16 res = (__force u16)csum; | |
75 | ||
76 | res += (__force u16)addend; | |
77 | return (__force __sum16)(res + (res < (__force u16)addend)); | |
78 | } | |
79 | ||
80 | static inline __sum16 csum16_sub(__sum16 csum, __be16 addend) | |
81 | { | |
82 | return csum16_add(csum, ~addend); | |
83 | } | |
84 | ||
56649d5d AV |
85 | static inline __wsum |
86 | csum_block_add(__wsum csum, __wsum csum2, int offset) | |
1da177e4 | 87 | { |
56649d5d | 88 | u32 sum = (__force u32)csum2; |
1da177e4 | 89 | if (offset&1) |
56649d5d AV |
90 | sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF); |
91 | return csum_add(csum, (__force __wsum)sum); | |
1da177e4 LT |
92 | } |
93 | ||
2817a336 DB |
94 | static inline __wsum |
95 | csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len) | |
96 | { | |
97 | return csum_block_add(csum, csum2, offset); | |
98 | } | |
99 | ||
56649d5d AV |
100 | static inline __wsum |
101 | csum_block_sub(__wsum csum, __wsum csum2, int offset) | |
1da177e4 | 102 | { |
56649d5d | 103 | u32 sum = (__force u32)csum2; |
1da177e4 | 104 | if (offset&1) |
56649d5d AV |
105 | sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF); |
106 | return csum_sub(csum, (__force __wsum)sum); | |
107 | } | |
108 | ||
109 | static inline __wsum csum_unfold(__sum16 n) | |
110 | { | |
111 | return (__force __wsum)n; | |
1da177e4 LT |
112 | } |
113 | ||
cea80ea8 DB |
114 | static inline __wsum csum_partial_ext(const void *buff, int len, __wsum sum) |
115 | { | |
116 | return csum_partial(buff, len, sum); | |
117 | } | |
118 | ||
f6ab0288 | 119 | #define CSUM_MANGLED_0 ((__force __sum16)0xffff) |
a99a00cf PM |
120 | |
121 | static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to) | |
122 | { | |
123 | __be32 diff[] = { ~from, to }; | |
124 | ||
07f0757a | 125 | *sum = csum_fold(csum_partial(diff, sizeof(diff), ~csum_unfold(*sum))); |
a99a00cf PM |
126 | } |
127 | ||
99f0b958 ED |
128 | /* Implements RFC 1624 (Incremental Internet Checksum) |
129 | * 3. Discussion states : | |
130 | * HC' = ~(~HC + ~m + m') | |
131 | * m : old value of a 16bit field | |
132 | * m' : new value of a 16bit field | |
133 | */ | |
134 | static inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new) | |
a99a00cf | 135 | { |
99f0b958 | 136 | *sum = ~csum16_add(csum16_sub(~(*sum), old), new); |
a99a00cf PM |
137 | } |
138 | ||
139 | struct sk_buff; | |
4fc70747 JP |
140 | void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb, |
141 | __be32 from, __be32 to, int pseudohdr); | |
142 | void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb, | |
143 | const __be32 *from, const __be32 *to, | |
144 | int pseudohdr); | |
a99a00cf PM |
145 | |
146 | static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, | |
147 | __be16 from, __be16 to, | |
148 | int pseudohdr) | |
149 | { | |
150 | inet_proto_csum_replace4(sum, skb, (__force __be32)from, | |
151 | (__force __be32)to, pseudohdr); | |
152 | } | |
153 | ||
1da177e4 | 154 | #endif |