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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/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Checksumming functions for IP, TCP, UDP and so on
8 *
9 * Authors: Jorge Cwik, <jorge@laser.satlink.net>
10 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
11 * Borrows very liberally from tcp.c and ip.c, see those
12 * files for more names.
13 */
14
15#ifndef _CHECKSUM_H
16#define _CHECKSUM_H
17
18#include <linux/errno.h>
19#include <asm/types.h>
20#include <asm/byteorder.h>
21#include <asm/checksum.h>
22#if !defined(_HAVE_ARCH_COPY_AND_CSUM_FROM_USER) || !defined(HAVE_CSUM_COPY_USER)
23#include <linux/uaccess.h>
24#endif
25
26#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
27static __always_inline
28__wsum csum_and_copy_from_user (const void __user *src, void *dst,
29 int len)
30{
31 if (copy_from_user(dst, src, len))
32 return 0;
33 return csum_partial(dst, len, ~0U);
34}
35#endif
36
37#ifndef HAVE_CSUM_COPY_USER
38static __always_inline __wsum csum_and_copy_to_user
39(const void *src, void __user *dst, int len)
40{
41 __wsum sum = csum_partial(src, len, ~0U);
42
43 if (copy_to_user(dst, src, len) == 0)
44 return sum;
45 return 0;
46}
47#endif
48
49#ifndef _HAVE_ARCH_CSUM_AND_COPY
50static __always_inline __wsum
51csum_partial_copy_nocheck(const void *src, void *dst, int len)
52{
53 memcpy(dst, src, len);
54 return csum_partial(dst, len, 0);
55}
56#endif
57
58#ifndef HAVE_ARCH_CSUM_ADD
59static __always_inline __wsum csum_add(__wsum csum, __wsum addend)
60{
61 u32 res = (__force u32)csum;
62 res += (__force u32)addend;
63 return (__force __wsum)(res + (res < (__force u32)addend));
64}
65#endif
66
67static __always_inline __wsum csum_sub(__wsum csum, __wsum addend)
68{
69 return csum_add(csum, ~addend);
70}
71
72static __always_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 __always_inline __sum16 csum16_sub(__sum16 csum, __be16 addend)
81{
82 return csum16_add(csum, ~addend);
83}
84
85#ifndef HAVE_ARCH_CSUM_SHIFT
86static __always_inline __wsum csum_shift(__wsum sum, int offset)
87{
88 /* rotate sum to align it with a 16b boundary */
89 if (offset & 1)
90 return (__force __wsum)ror32((__force u32)sum, 8);
91 return sum;
92}
93#endif
94
95static __always_inline __wsum
96csum_block_add(__wsum csum, __wsum csum2, int offset)
97{
98 return csum_add(csum, csum_shift(csum2, offset));
99}
100
101static __always_inline __wsum
102csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len)
103{
104 return csum_block_add(csum, csum2, offset);
105}
106
107static __always_inline __wsum
108csum_block_sub(__wsum csum, __wsum csum2, int offset)
109{
110 return csum_block_add(csum, ~csum2, offset);
111}
112
113static __always_inline __wsum csum_unfold(__sum16 n)
114{
115 return (__force __wsum)n;
116}
117
118static __always_inline
119__wsum csum_partial_ext(const void *buff, int len, __wsum sum)
120{
121 return csum_partial(buff, len, sum);
122}
123
124#define CSUM_MANGLED_0 ((__force __sum16)0xffff)
125
126static __always_inline void csum_replace_by_diff(__sum16 *sum, __wsum diff)
127{
128 *sum = csum_fold(csum_add(diff, ~csum_unfold(*sum)));
129}
130
131static __always_inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to)
132{
133 __wsum tmp = csum_sub(~csum_unfold(*sum), (__force __wsum)from);
134
135 *sum = csum_fold(csum_add(tmp, (__force __wsum)to));
136}
137
138/* Implements RFC 1624 (Incremental Internet Checksum)
139 * 3. Discussion states :
140 * HC' = ~(~HC + ~m + m')
141 * m : old value of a 16bit field
142 * m' : new value of a 16bit field
143 */
144static __always_inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new)
145{
146 *sum = ~csum16_add(csum16_sub(~(*sum), old), new);
147}
148
149static inline void csum_replace(__wsum *csum, __wsum old, __wsum new)
150{
151 *csum = csum_add(csum_sub(*csum, old), new);
152}
153
154struct sk_buff;
155void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
156 __be32 from, __be32 to, bool pseudohdr);
157void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
158 const __be32 *from, const __be32 *to,
159 bool pseudohdr);
160void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
161 __wsum diff, bool pseudohdr);
162
163static __always_inline
164void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
165 __be16 from, __be16 to, bool pseudohdr)
166{
167 inet_proto_csum_replace4(sum, skb, (__force __be32)from,
168 (__force __be32)to, pseudohdr);
169}
170
171static __always_inline __wsum remcsum_adjust(void *ptr, __wsum csum,
172 int start, int offset)
173{
174 __sum16 *psum = (__sum16 *)(ptr + offset);
175 __wsum delta;
176
177 /* Subtract out checksum up to start */
178 csum = csum_sub(csum, csum_partial(ptr, start, 0));
179
180 /* Set derived checksum in packet */
181 delta = csum_sub((__force __wsum)csum_fold(csum),
182 (__force __wsum)*psum);
183 *psum = csum_fold(csum);
184
185 return delta;
186}
187
188static __always_inline void remcsum_unadjust(__sum16 *psum, __wsum delta)
189{
190 *psum = csum_fold(csum_sub(delta, (__force __wsum)*psum));
191}
192
193static __always_inline __wsum wsum_negate(__wsum val)
194{
195 return (__force __wsum)-((__force u32)val);
196}
197#endif