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 <linux/uaccess.h> |
22 | #include <asm/checksum.h> |
23 | |
24 | #ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER |
25 | static __always_inline |
26 | __wsum csum_and_copy_from_user (const void __user *src, void *dst, |
27 | int len) |
28 | { |
29 | if (copy_from_user(dst, src, len)) |
30 | return 0; |
31 | return csum_partial(dst, len, ~0U); |
32 | } |
33 | #endif |
34 | |
35 | #ifndef HAVE_CSUM_COPY_USER |
36 | static __always_inline __wsum csum_and_copy_to_user |
37 | (const void *src, void __user *dst, int len) |
38 | { |
39 | __wsum sum = csum_partial(src, len, ~0U); |
40 | |
41 | if (copy_to_user(dst, src, len) == 0) |
42 | return sum; |
43 | return 0; |
44 | } |
45 | #endif |
46 | |
47 | #ifndef _HAVE_ARCH_CSUM_AND_COPY |
48 | static __always_inline __wsum |
49 | csum_partial_copy_nocheck(const void *src, void *dst, int len) |
50 | { |
51 | memcpy(dst, src, len); |
52 | return csum_partial(dst, len, 0); |
53 | } |
54 | #endif |
55 | |
56 | #ifndef HAVE_ARCH_CSUM_ADD |
57 | static __always_inline __wsum csum_add(__wsum csum, __wsum addend) |
58 | { |
59 | u32 res = (__force u32)csum; |
60 | res += (__force u32)addend; |
61 | return (__force __wsum)(res + (res < (__force u32)addend)); |
62 | } |
63 | #endif |
64 | |
65 | static __always_inline __wsum csum_sub(__wsum csum, __wsum addend) |
66 | { |
67 | return csum_add(csum, ~addend); |
68 | } |
69 | |
70 | static __always_inline __sum16 csum16_add(__sum16 csum, __be16 addend) |
71 | { |
72 | u16 res = (__force u16)csum; |
73 | |
74 | res += (__force u16)addend; |
75 | return (__force __sum16)(res + (res < (__force u16)addend)); |
76 | } |
77 | |
78 | static __always_inline __sum16 csum16_sub(__sum16 csum, __be16 addend) |
79 | { |
80 | return csum16_add(csum, ~addend); |
81 | } |
82 | |
83 | #ifndef HAVE_ARCH_CSUM_SHIFT |
84 | static __always_inline __wsum csum_shift(__wsum sum, int offset) |
85 | { |
86 | /* rotate sum to align it with a 16b boundary */ |
87 | if (offset & 1) |
88 | return (__force __wsum)ror32((__force u32)sum, 8); |
89 | return sum; |
90 | } |
91 | #endif |
92 | |
93 | static __always_inline __wsum |
94 | csum_block_add(__wsum csum, __wsum csum2, int offset) |
95 | { |
96 | return csum_add(csum, csum_shift(csum2, offset)); |
97 | } |
98 | |
99 | static __always_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 __always_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 __always_inline __wsum csum_unfold(__sum16 n) |
112 | { |
113 | return (__force __wsum)n; |
114 | } |
115 | |
116 | static __always_inline |
117 | __wsum csum_partial_ext(const void *buff, int len, __wsum sum) |
118 | { |
119 | return csum_partial(buff, len, sum); |
120 | } |
121 | |
122 | #define CSUM_MANGLED_0 ((__force __sum16)0xffff) |
123 | |
124 | static __always_inline void csum_replace_by_diff(__sum16 *sum, __wsum diff) |
125 | { |
126 | *sum = csum_fold(csum_add(diff, ~csum_unfold(*sum))); |
127 | } |
128 | |
129 | static __always_inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to) |
130 | { |
131 | __wsum tmp = csum_sub(~csum_unfold(*sum), (__force __wsum)from); |
132 | |
133 | *sum = csum_fold(csum_add(tmp, (__force __wsum)to)); |
134 | } |
135 | |
136 | /* Implements RFC 1624 (Incremental Internet Checksum) |
137 | * 3. Discussion states : |
138 | * HC' = ~(~HC + ~m + m') |
139 | * m : old value of a 16bit field |
140 | * m' : new value of a 16bit field |
141 | */ |
142 | static __always_inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new) |
143 | { |
144 | *sum = ~csum16_add(csum16_sub(~(*sum), old), new); |
145 | } |
146 | |
147 | static inline void csum_replace(__wsum *csum, __wsum old, __wsum new) |
148 | { |
149 | *csum = csum_add(csum_sub(*csum, old), new); |
150 | } |
151 | |
152 | struct sk_buff; |
153 | void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb, |
154 | __be32 from, __be32 to, bool pseudohdr); |
155 | void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb, |
156 | const __be32 *from, const __be32 *to, |
157 | bool pseudohdr); |
158 | void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb, |
159 | __wsum diff, bool pseudohdr); |
160 | |
161 | static __always_inline |
162 | void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, |
163 | __be16 from, __be16 to, bool pseudohdr) |
164 | { |
165 | inet_proto_csum_replace4(sum, skb, (__force __be32)from, |
166 | (__force __be32)to, pseudohdr); |
167 | } |
168 | |
169 | static __always_inline __wsum remcsum_adjust(void *ptr, __wsum csum, |
170 | int start, int offset) |
171 | { |
172 | __sum16 *psum = (__sum16 *)(ptr + offset); |
173 | __wsum delta; |
174 | |
175 | /* Subtract out checksum up to start */ |
176 | csum = csum_sub(csum, csum_partial(ptr, start, 0)); |
177 | |
178 | /* Set derived checksum in packet */ |
179 | delta = csum_sub((__force __wsum)csum_fold(csum), |
180 | (__force __wsum)*psum); |
181 | *psum = csum_fold(csum); |
182 | |
183 | return delta; |
184 | } |
185 | |
186 | static __always_inline void remcsum_unadjust(__sum16 *psum, __wsum delta) |
187 | { |
188 | *psum = csum_fold(csum_sub(delta, (__force __wsum)*psum)); |
189 | } |
190 | |
191 | static __always_inline __wsum wsum_negate(__wsum val) |
192 | { |
193 | return (__force __wsum)-((__force u32)val); |
194 | } |
195 | #endif |
196 | |