]>
Commit | Line | Data |
---|---|---|
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 | |
30 | __wsum csum_and_copy_from_user (const void __user *src, void *dst, | |
31 | int len, __wsum sum, int *err_ptr) | |
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 | |
44 | static __inline__ __wsum csum_and_copy_to_user | |
45 | (const void *src, void __user *dst, int len, __wsum sum, int *err_ptr) | |
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 | ||
56 | return (__force __wsum)-1; /* invalid checksum */ | |
57 | } | |
58 | #endif | |
59 | ||
60 | #ifndef HAVE_ARCH_CSUM_ADD | |
61 | static inline __wsum csum_add(__wsum csum, __wsum addend) | |
62 | { | |
63 | u32 res = (__force u32)csum; | |
64 | res += (__force u32)addend; | |
65 | return (__force __wsum)(res + (res < (__force u32)addend)); | |
66 | } | |
67 | #endif | |
68 | ||
69 | static inline __wsum csum_sub(__wsum csum, __wsum addend) | |
70 | { | |
71 | return csum_add(csum, ~addend); | |
72 | } | |
73 | ||
74 | static inline __sum16 csum16_add(__sum16 csum, __be16 addend) | |
75 | { | |
76 | u16 res = (__force u16)csum; | |
77 | ||
78 | res += (__force u16)addend; | |
79 | return (__force __sum16)(res + (res < (__force u16)addend)); | |
80 | } | |
81 | ||
82 | static inline __sum16 csum16_sub(__sum16 csum, __be16 addend) | |
83 | { | |
84 | return csum16_add(csum, ~addend); | |
85 | } | |
86 | ||
87 | static inline __wsum | |
88 | csum_block_add(__wsum csum, __wsum csum2, int offset) | |
89 | { | |
90 | u32 sum = (__force u32)csum2; | |
91 | ||
92 | /* rotate sum to align it with a 16b boundary */ | |
93 | if (offset & 1) | |
94 | sum = ror32(sum, 8); | |
95 | ||
96 | return csum_add(csum, (__force __wsum)sum); | |
97 | } | |
98 | ||
99 | static inline __wsum | |
100 | csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len) | |
101 | { | |
102 | return csum_block_add(csum, csum2, offset); | |
103 | } | |
104 | ||
105 | static inline __wsum | |
106 | csum_block_sub(__wsum csum, __wsum csum2, int offset) | |
107 | { | |
108 | return csum_block_add(csum, ~csum2, offset); | |
109 | } | |
110 | ||
111 | static inline __wsum csum_unfold(__sum16 n) | |
112 | { | |
113 | return (__force __wsum)n; | |
114 | } | |
115 | ||
116 | static inline __wsum csum_partial_ext(const void *buff, int len, __wsum sum) | |
117 | { | |
118 | return csum_partial(buff, len, sum); | |
119 | } | |
120 | ||
121 | #define CSUM_MANGLED_0 ((__force __sum16)0xffff) | |
122 | ||
123 | static inline void csum_replace_by_diff(__sum16 *sum, __wsum diff) | |
124 | { | |
125 | *sum = csum_fold(csum_add(diff, ~csum_unfold(*sum))); | |
126 | } | |
127 | ||
128 | static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to) | |
129 | { | |
130 | __wsum tmp = csum_sub(~csum_unfold(*sum), (__force __wsum)from); | |
131 | ||
132 | *sum = csum_fold(csum_add(tmp, (__force __wsum)to)); | |
133 | } | |
134 | ||
135 | /* Implements RFC 1624 (Incremental Internet Checksum) | |
136 | * 3. Discussion states : | |
137 | * HC' = ~(~HC + ~m + m') | |
138 | * m : old value of a 16bit field | |
139 | * m' : new value of a 16bit field | |
140 | */ | |
141 | static inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new) | |
142 | { | |
143 | *sum = ~csum16_add(csum16_sub(~(*sum), old), new); | |
144 | } | |
145 | ||
146 | struct sk_buff; | |
147 | void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb, | |
148 | __be32 from, __be32 to, bool pseudohdr); | |
149 | void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb, | |
150 | const __be32 *from, const __be32 *to, | |
151 | bool pseudohdr); | |
152 | void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb, | |
153 | __wsum diff, bool pseudohdr); | |
154 | ||
155 | static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, | |
156 | __be16 from, __be16 to, | |
157 | bool pseudohdr) | |
158 | { | |
159 | inet_proto_csum_replace4(sum, skb, (__force __be32)from, | |
160 | (__force __be32)to, pseudohdr); | |
161 | } | |
162 | ||
163 | static inline __wsum remcsum_adjust(void *ptr, __wsum csum, | |
164 | int start, int offset) | |
165 | { | |
166 | __sum16 *psum = (__sum16 *)(ptr + offset); | |
167 | __wsum delta; | |
168 | ||
169 | /* Subtract out checksum up to start */ | |
170 | csum = csum_sub(csum, csum_partial(ptr, start, 0)); | |
171 | ||
172 | /* Set derived checksum in packet */ | |
173 | delta = csum_sub((__force __wsum)csum_fold(csum), | |
174 | (__force __wsum)*psum); | |
175 | *psum = csum_fold(csum); | |
176 | ||
177 | return delta; | |
178 | } | |
179 | ||
180 | static inline void remcsum_unadjust(__sum16 *psum, __wsum delta) | |
181 | { | |
182 | *psum = csum_fold(csum_sub(delta, *psum)); | |
183 | } | |
184 | ||
185 | #endif |