1 #ifndef __ASM_GENERIC_CHECKSUM_H
2 #define __ASM_GENERIC_CHECKSUM_H
5 * computes the checksum of a memory block at buff, length len,
6 * and adds in "sum" (32-bit)
8 * returns a 32-bit number suitable for feeding into itself
11 * this function must be called with even lengths, except
12 * for the last fragment, which may be odd
14 * it's best to have buff aligned on a 32-bit boundary
16 extern __wsum
csum_partial(const void *buff
, int len
, __wsum sum
);
19 * the same as csum_partial, but copies from src while it
22 * here even more important to align src and dst on a 32-bit (or even
23 * better 64-bit) boundary
25 extern __wsum
csum_partial_copy(const void *src
, void *dst
, int len
, __wsum sum
);
28 * the same as csum_partial_copy, but copies from user space.
30 * here even more important to align src and dst on a 32-bit (or even
31 * better 64-bit) boundary
33 extern __wsum
csum_partial_copy_from_user(const void __user
*src
, void *dst
,
34 int len
, __wsum sum
, int *csum_err
);
36 #ifndef csum_partial_copy_nocheck
37 #define csum_partial_copy_nocheck(src, dst, len, sum) \
38 csum_partial_copy((src), (dst), (len), (sum))
42 * This is a version of ip_compute_csum() optimized for IP headers,
43 * which always checksum on 4 octet boundaries.
45 extern __sum16
ip_fast_csum(const void *iph
, unsigned int ihl
);
48 * Fold a partial checksum
50 static inline __sum16
csum_fold(__wsum csum
)
52 u32 sum
= (__force u32
)csum
;
53 sum
= (sum
& 0xffff) + (sum
>> 16);
54 sum
= (sum
& 0xffff) + (sum
>> 16);
55 return (__force __sum16
)~sum
;
58 #ifndef csum_tcpudp_nofold
60 * computes the checksum of the TCP/UDP pseudo-header
61 * returns a 16-bit checksum, already complemented
64 csum_tcpudp_nofold(__be32 saddr
, __be32 daddr
, unsigned short len
,
65 unsigned short proto
, __wsum sum
);
68 #ifndef csum_tcpudp_magic
70 csum_tcpudp_magic(__be32 saddr
, __be32 daddr
, unsigned short len
,
71 unsigned short proto
, __wsum sum
)
73 return csum_fold(csum_tcpudp_nofold(saddr
, daddr
, len
, proto
, sum
));
78 * this routine is used for miscellaneous IP-like checksums, mainly
81 extern __sum16
ip_compute_csum(const void *buff
, int len
);
83 #endif /* __ASM_GENERIC_CHECKSUM_H */
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