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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
29static 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
44static __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
60static inline __wsum csum_add(__wsum csum, __wsum addend)
61{
62 u32 res = (__force u32)csum;
63 res += (__force u32)addend;
64 return (__force __wsum)(res + (res < (__force u32)addend));
65}
66
67static inline __wsum csum_sub(__wsum csum, __wsum addend)
68{
69 return csum_add(csum, ~addend);
70}
71
72static inline __wsum
73csum_block_add(__wsum csum, __wsum csum2, int offset)
74{
75 u32 sum = (__force u32)csum2;
76 if (offset&1)
77 sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
78 return csum_add(csum, (__force __wsum)sum);
79}
80
81static inline __wsum
82csum_block_sub(__wsum csum, __wsum csum2, int offset)
83{
84 u32 sum = (__force u32)csum2;
85 if (offset&1)
86 sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
87 return csum_sub(csum, (__force __wsum)sum);
88}
89
90static inline __wsum csum_unfold(__sum16 n)
91{
92 return (__force __wsum)n;
93}
94
95#define CSUM_MANGLED_0 ((__force __sum16)0xffff)
96
97static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to)
98{
99 __be32 diff[] = { ~from, to };
100
101 *sum = csum_fold(csum_partial(diff, sizeof(diff), ~csum_unfold(*sum)));
102}
103
104static inline void csum_replace2(__sum16 *sum, __be16 from, __be16 to)
105{
106 csum_replace4(sum, (__force __be32)from, (__force __be32)to);
107}
108
109struct sk_buff;
110extern void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
111 __be32 from, __be32 to, int pseudohdr);
112
113static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
114 __be16 from, __be16 to,
115 int pseudohdr)
116{
117 inet_proto_csum_replace4(sum, skb, (__force __be32)from,
118 (__force __be32)to, pseudohdr);
119}
120
121#endif
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
29static 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
44static __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
60static inline __wsum csum_add(__wsum csum, __wsum addend)
61{
62 u32 res = (__force u32)csum;
63 res += (__force u32)addend;
64 return (__force __wsum)(res + (res < (__force u32)addend));
65}
66
67static inline __wsum csum_sub(__wsum csum, __wsum addend)
68{
69 return csum_add(csum, ~addend);
70}
71
72static 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
80static inline __sum16 csum16_sub(__sum16 csum, __be16 addend)
81{
82 return csum16_add(csum, ~addend);
83}
84
85static inline __wsum
86csum_block_add(__wsum csum, __wsum csum2, int offset)
87{
88 u32 sum = (__force u32)csum2;
89 if (offset&1)
90 sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
91 return csum_add(csum, (__force __wsum)sum);
92}
93
94static inline __wsum
95csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len)
96{
97 return csum_block_add(csum, csum2, offset);
98}
99
100static inline __wsum
101csum_block_sub(__wsum csum, __wsum csum2, int offset)
102{
103 u32 sum = (__force u32)csum2;
104 if (offset&1)
105 sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
106 return csum_sub(csum, (__force __wsum)sum);
107}
108
109static inline __wsum csum_unfold(__sum16 n)
110{
111 return (__force __wsum)n;
112}
113
114static inline __wsum csum_partial_ext(const void *buff, int len, __wsum sum)
115{
116 return csum_partial(buff, len, sum);
117}
118
119#define CSUM_MANGLED_0 ((__force __sum16)0xffff)
120
121static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to)
122{
123 __be32 diff[] = { ~from, to };
124
125 *sum = csum_fold(csum_partial(diff, sizeof(diff), ~csum_unfold(*sum)));
126}
127
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 */
134static inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new)
135{
136 *sum = ~csum16_add(csum16_sub(~(*sum), old), new);
137}
138
139struct sk_buff;
140void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
141 __be32 from, __be32 to, int pseudohdr);
142void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
143 const __be32 *from, const __be32 *to,
144 int pseudohdr);
145
146static 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
154#endif