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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Al Viro56649d52006-11-14 21:23:59 -080030__wsum csum_and_copy_from_user (const void __user *src, void *dst,
31 int len, __wsum sum, int *err_ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070032{
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
Al Viro56649d52006-11-14 21:23:59 -080044static __inline__ __wsum csum_and_copy_to_user
45(const void *src, void __user *dst, int len, __wsum sum, int *err_ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070046{
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
Al Viro56649d52006-11-14 21:23:59 -080056 return (__force __wsum)-1; /* invalid checksum */
Linus Torvalds1da177e2005-04-16 15:20:36 -070057}
58#endif
59
Tom Herbert07064c62014-05-02 16:28:03 -070060#ifndef HAVE_ARCH_CSUM_ADD
Al Viro56649d52006-11-14 21:23:59 -080061static inline __wsum csum_add(__wsum csum, __wsum addend)
Linus Torvalds1da177e2005-04-16 15:20:36 -070062{
Al Viro56649d52006-11-14 21:23:59 -080063 u32 res = (__force u32)csum;
64 res += (__force u32)addend;
65 return (__force __wsum)(res + (res < (__force u32)addend));
Linus Torvalds1da177e2005-04-16 15:20:36 -070066}
Tom Herbert07064c62014-05-02 16:28:03 -070067#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070068
Al Viro56649d52006-11-14 21:23:59 -080069static inline __wsum csum_sub(__wsum csum, __wsum addend)
Linus Torvalds1da177e2005-04-16 15:20:36 -070070{
71 return csum_add(csum, ~addend);
72}
73
Eric Dumazet99f0b952014-03-23 19:51:36 -070074static 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
82static inline __sum16 csum16_sub(__sum16 csum, __be16 addend)
83{
84 return csum16_add(csum, ~addend);
85}
86
Al Viro56649d52006-11-14 21:23:59 -080087static inline __wsum
88csum_block_add(__wsum csum, __wsum csum2, int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -070089{
Al Viro56649d52006-11-14 21:23:59 -080090 u32 sum = (__force u32)csum2;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 if (offset&1)
Al Viro56649d52006-11-14 21:23:59 -080092 sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
93 return csum_add(csum, (__force __wsum)sum);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094}
95
Al Viro56649d52006-11-14 21:23:59 -080096static inline __wsum
Daniel Borkmann2817a332013-10-30 11:50:51 +010097csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len)
98{
99 return csum_block_add(csum, csum2, offset);
100}
101
102static inline __wsum
Al Viro56649d52006-11-14 21:23:59 -0800103csum_block_sub(__wsum csum, __wsum csum2, int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104{
Al Viro56649d52006-11-14 21:23:59 -0800105 u32 sum = (__force u32)csum2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 if (offset&1)
Al Viro56649d52006-11-14 21:23:59 -0800107 sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
108 return csum_sub(csum, (__force __wsum)sum);
109}
110
111static inline __wsum csum_unfold(__sum16 n)
112{
113 return (__force __wsum)n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114}
115
Daniel Borkmanncea80ea2013-11-04 17:10:25 +0100116static inline __wsum csum_partial_ext(const void *buff, int len, __wsum sum)
117{
118 return csum_partial(buff, len, sum);
119}
120
Al Virof6ab0282006-11-16 02:36:50 -0800121#define CSUM_MANGLED_0 ((__force __sum16)0xffff)
Patrick McHardya99a00c2007-11-30 01:14:30 +1100122
123static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to)
124{
LEROY Christophe4565af02014-09-23 10:54:32 +0200125 *sum = csum_fold(csum_add(csum_sub(~csum_unfold(*sum), from), to));
Patrick McHardya99a00c2007-11-30 01:14:30 +1100126}
127
Eric Dumazet99f0b952014-03-23 19:51:36 -0700128/* 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)
Patrick McHardya99a00c2007-11-30 01:14:30 +1100135{
Eric Dumazet99f0b952014-03-23 19:51:36 -0700136 *sum = ~csum16_add(csum16_sub(~(*sum), old), new);
Patrick McHardya99a00c2007-11-30 01:14:30 +1100137}
138
139struct sk_buff;
Joe Perches4fc70742013-07-31 17:31:38 -0700140void 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);
Patrick McHardya99a00c2007-11-30 01:14:30 +1100145
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154#endif