1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun #ifndef __ASM_GENERIC_CHECKSUM_H
3*4882a593Smuzhiyun #define __ASM_GENERIC_CHECKSUM_H
4*4882a593Smuzhiyun
5*4882a593Smuzhiyun /*
6*4882a593Smuzhiyun * computes the checksum of a memory block at buff, length len,
7*4882a593Smuzhiyun * and adds in "sum" (32-bit)
8*4882a593Smuzhiyun *
9*4882a593Smuzhiyun * returns a 32-bit number suitable for feeding into itself
10*4882a593Smuzhiyun * or csum_tcpudp_magic
11*4882a593Smuzhiyun *
12*4882a593Smuzhiyun * this function must be called with even lengths, except
13*4882a593Smuzhiyun * for the last fragment, which may be odd
14*4882a593Smuzhiyun *
15*4882a593Smuzhiyun * it's best to have buff aligned on a 32-bit boundary
16*4882a593Smuzhiyun */
17*4882a593Smuzhiyun extern __wsum csum_partial(const void *buff, int len, __wsum sum);
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun #ifndef ip_fast_csum
20*4882a593Smuzhiyun /*
21*4882a593Smuzhiyun * This is a version of ip_compute_csum() optimized for IP headers,
22*4882a593Smuzhiyun * which always checksum on 4 octet boundaries.
23*4882a593Smuzhiyun */
24*4882a593Smuzhiyun extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
25*4882a593Smuzhiyun #endif
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun #ifndef csum_fold
28*4882a593Smuzhiyun /*
29*4882a593Smuzhiyun * Fold a partial checksum
30*4882a593Smuzhiyun */
csum_fold(__wsum csum)31*4882a593Smuzhiyun static inline __sum16 csum_fold(__wsum csum)
32*4882a593Smuzhiyun {
33*4882a593Smuzhiyun u32 sum = (__force u32)csum;
34*4882a593Smuzhiyun sum = (sum & 0xffff) + (sum >> 16);
35*4882a593Smuzhiyun sum = (sum & 0xffff) + (sum >> 16);
36*4882a593Smuzhiyun return (__force __sum16)~sum;
37*4882a593Smuzhiyun }
38*4882a593Smuzhiyun #endif
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun #ifndef csum_tcpudp_nofold
41*4882a593Smuzhiyun /*
42*4882a593Smuzhiyun * computes the checksum of the TCP/UDP pseudo-header
43*4882a593Smuzhiyun * returns a 16-bit checksum, already complemented
44*4882a593Smuzhiyun */
45*4882a593Smuzhiyun extern __wsum
46*4882a593Smuzhiyun csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
47*4882a593Smuzhiyun __u8 proto, __wsum sum);
48*4882a593Smuzhiyun #endif
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun #ifndef csum_tcpudp_magic
51*4882a593Smuzhiyun static inline __sum16
csum_tcpudp_magic(__be32 saddr,__be32 daddr,__u32 len,__u8 proto,__wsum sum)52*4882a593Smuzhiyun csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
53*4882a593Smuzhiyun __u8 proto, __wsum sum)
54*4882a593Smuzhiyun {
55*4882a593Smuzhiyun return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
56*4882a593Smuzhiyun }
57*4882a593Smuzhiyun #endif
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun /*
60*4882a593Smuzhiyun * this routine is used for miscellaneous IP-like checksums, mainly
61*4882a593Smuzhiyun * in icmp.c
62*4882a593Smuzhiyun */
63*4882a593Smuzhiyun extern __sum16 ip_compute_csum(const void *buff, int len);
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun #endif /* __ASM_GENERIC_CHECKSUM_H */
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