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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>
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -080025#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#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;
Alexander Duyck33803962016-03-09 09:25:26 -080091
92 /* rotate sum to align it with a 16b boundary */
93 if (offset & 1)
94 sum = ror32(sum, 8);
95
Al Viro56649d52006-11-14 21:23:59 -080096 return csum_add(csum, (__force __wsum)sum);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097}
98
Al Viro56649d52006-11-14 21:23:59 -080099static inline __wsum
Daniel Borkmann2817a332013-10-30 11:50:51 +0100100csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len)
101{
102 return csum_block_add(csum, csum2, offset);
103}
104
105static inline __wsum
Al Viro56649d52006-11-14 21:23:59 -0800106csum_block_sub(__wsum csum, __wsum csum2, int offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107{
Alexander Duyck33803962016-03-09 09:25:26 -0800108 return csum_block_add(csum, ~csum2, offset);
Al Viro56649d52006-11-14 21:23:59 -0800109}
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
Daniel Borkmann8050c0f2016-03-04 15:15:02 +0100123static inline void csum_replace_by_diff(__sum16 *sum, __wsum diff)
124{
125 *sum = csum_fold(csum_add(diff, ~csum_unfold(*sum)));
126}
127
Patrick McHardya99a00c2007-11-30 01:14:30 +1100128static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to)
129{
Eric Dumazetd53a2aa2015-05-15 08:52:19 -0700130 __wsum tmp = csum_sub(~csum_unfold(*sum), (__force __wsum)from);
131
132 *sum = csum_fold(csum_add(tmp, (__force __wsum)to));
Patrick McHardya99a00c2007-11-30 01:14:30 +1100133}
134
Eric Dumazet99f0b952014-03-23 19:51:36 -0700135/* 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 */
141static inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new)
Patrick McHardya99a00c2007-11-30 01:14:30 +1100142{
Eric Dumazet99f0b952014-03-23 19:51:36 -0700143 *sum = ~csum16_add(csum16_sub(~(*sum), old), new);
Patrick McHardya99a00c2007-11-30 01:14:30 +1100144}
145
146struct sk_buff;
Joe Perches4fc70742013-07-31 17:31:38 -0700147void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
Tom Herbert4b048d62015-08-17 13:42:25 -0700148 __be32 from, __be32 to, bool pseudohdr);
Joe Perches4fc70742013-07-31 17:31:38 -0700149void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
150 const __be32 *from, const __be32 *to,
Tom Herbert4b048d62015-08-17 13:42:25 -0700151 bool pseudohdr);
Tom Herbertabc5d1f2015-08-17 13:42:26 -0700152void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
153 __wsum diff, bool pseudohdr);
Patrick McHardya99a00c2007-11-30 01:14:30 +1100154
155static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
156 __be16 from, __be16 to,
Tom Herbert4b048d62015-08-17 13:42:25 -0700157 bool pseudohdr)
Patrick McHardya99a00c2007-11-30 01:14:30 +1100158{
159 inet_proto_csum_replace4(sum, skb, (__force __be32)from,
160 (__force __be32)to, pseudohdr);
161}
162
Tom Herbert7c967b22014-11-25 11:21:19 -0800163static 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 */
Tom Herbert369620a2015-12-10 12:37:44 -0800173 delta = csum_sub((__force __wsum)csum_fold(csum),
174 (__force __wsum)*psum);
Tom Herbert7c967b22014-11-25 11:21:19 -0800175 *psum = csum_fold(csum);
176
177 return delta;
178}
179
Tom Herbert26c4f7d2015-02-10 16:30:27 -0800180static inline void remcsum_unadjust(__sum16 *psum, __wsum delta)
181{
182 *psum = csum_fold(csum_sub(delta, *psum));
183}
184
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185#endif