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1 | /* SPDX-License-Identifier: GPL-2.0 */ | |
2 | #ifndef __ASM_GENERIC_CHECKSUM_H | |
3 | #define __ASM_GENERIC_CHECKSUM_H | |
4 | ||
5 | /* | |
6 | * computes the checksum of a memory block at buff, length len, | |
7 | * and adds in "sum" (32-bit) | |
8 | * | |
9 | * returns a 32-bit number suitable for feeding into itself | |
10 | * or csum_tcpudp_magic | |
11 | * | |
12 | * this function must be called with even lengths, except | |
13 | * for the last fragment, which may be odd | |
14 | * | |
15 | * it's best to have buff aligned on a 32-bit boundary | |
16 | */ | |
17 | extern __wsum csum_partial(const void *buff, int len, __wsum sum); | |
18 | ||
19 | /* | |
20 | * the same as csum_partial, but copies from src while it | |
21 | * checksums | |
22 | * | |
23 | * here even more important to align src and dst on a 32-bit (or even | |
24 | * better 64-bit) boundary | |
25 | */ | |
26 | extern __wsum csum_partial_copy(const void *src, void *dst, int len, __wsum sum); | |
27 | ||
28 | /* | |
29 | * the same as csum_partial_copy, but copies from user space. | |
30 | * | |
31 | * here even more important to align src and dst on a 32-bit (or even | |
32 | * better 64-bit) boundary | |
33 | */ | |
34 | extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst, | |
35 | int len, __wsum sum, int *csum_err); | |
36 | ||
37 | #ifndef csum_partial_copy_nocheck | |
38 | #define csum_partial_copy_nocheck(src, dst, len, sum) \ | |
39 | csum_partial_copy((src), (dst), (len), (sum)) | |
40 | #endif | |
41 | ||
42 | #ifndef ip_fast_csum | |
43 | /* | |
44 | * This is a version of ip_compute_csum() optimized for IP headers, | |
45 | * which always checksum on 4 octet boundaries. | |
46 | */ | |
47 | extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl); | |
48 | #endif | |
49 | ||
50 | #ifndef csum_fold | |
51 | /* | |
52 | * Fold a partial checksum | |
53 | */ | |
54 | static inline __sum16 csum_fold(__wsum csum) | |
55 | { | |
56 | u32 sum = (__force u32)csum; | |
57 | sum = (sum & 0xffff) + (sum >> 16); | |
58 | sum = (sum & 0xffff) + (sum >> 16); | |
59 | return (__force __sum16)~sum; | |
60 | } | |
61 | #endif | |
62 | ||
63 | #ifndef csum_tcpudp_nofold | |
64 | /* | |
65 | * computes the checksum of the TCP/UDP pseudo-header | |
66 | * returns a 16-bit checksum, already complemented | |
67 | */ | |
68 | extern __wsum | |
69 | csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, | |
70 | __u8 proto, __wsum sum); | |
71 | #endif | |
72 | ||
73 | #ifndef csum_tcpudp_magic | |
74 | static inline __sum16 | |
75 | csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len, | |
76 | __u8 proto, __wsum sum) | |
77 | { | |
78 | return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); | |
79 | } | |
80 | #endif | |
81 | ||
82 | /* | |
83 | * this routine is used for miscellaneous IP-like checksums, mainly | |
84 | * in icmp.c | |
85 | */ | |
86 | extern __sum16 ip_compute_csum(const void *buff, int len); | |
87 | ||
88 | #endif /* __ASM_GENERIC_CHECKSUM_H */ |