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 */
17extern __wsum csum_partial(const void *buff, int len, __wsum sum);
18
 
 
 
 
 
 
 
 
 
 
 
 
19#ifndef ip_fast_csum
20/*
21 * This is a version of ip_compute_csum() optimized for IP headers,
22 * which always checksum on 4 octet boundaries.
23 */
24extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
25#endif
26
27#ifndef csum_fold
28/*
29 * Fold a partial checksum
30 */
31static inline __sum16 csum_fold(__wsum csum)
32{
33	u32 sum = (__force u32)csum;
34	sum = (sum & 0xffff) + (sum >> 16);
35	sum = (sum & 0xffff) + (sum >> 16);
36	return (__force __sum16)~sum;
37}
38#endif
39
40#ifndef csum_tcpudp_nofold
41/*
42 * computes the checksum of the TCP/UDP pseudo-header
43 * returns a 16-bit checksum, already complemented
44 */
45extern __wsum
46csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
47		   __u8 proto, __wsum sum);
48#endif
49
50#ifndef csum_tcpudp_magic
51static inline __sum16
52csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
53		  __u8 proto, __wsum sum)
54{
55	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
56}
57#endif
58
59/*
60 * this routine is used for miscellaneous IP-like checksums, mainly
61 * in icmp.c
62 */
63extern __sum16 ip_compute_csum(const void *buff, int len);
64
65#endif /* __ASM_GENERIC_CHECKSUM_H */

 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 */
17extern __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#ifndef csum_partial_copy_nocheck
27__wsum csum_partial_copy_nocheck(const void *src, void *dst, int len,
28		__wsum sum);
29#endif
30
31#ifndef ip_fast_csum
32/*
33 * This is a version of ip_compute_csum() optimized for IP headers,
34 * which always checksum on 4 octet boundaries.
35 */
36extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
37#endif
38
39#ifndef csum_fold
40/*
41 * Fold a partial checksum
42 */
43static inline __sum16 csum_fold(__wsum csum)
44{
45	u32 sum = (__force u32)csum;
46	sum = (sum & 0xffff) + (sum >> 16);
47	sum = (sum & 0xffff) + (sum >> 16);
48	return (__force __sum16)~sum;
49}
50#endif
51
52#ifndef csum_tcpudp_nofold
53/*
54 * computes the checksum of the TCP/UDP pseudo-header
55 * returns a 16-bit checksum, already complemented
56 */
57extern __wsum
58csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
59		   __u8 proto, __wsum sum);
60#endif
61
62#ifndef csum_tcpudp_magic
63static inline __sum16
64csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
65		  __u8 proto, __wsum sum)
66{
67	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
68}
69#endif
70
71/*
72 * this routine is used for miscellaneous IP-like checksums, mainly
73 * in icmp.c
74 */
75extern __sum16 ip_compute_csum(const void *buff, int len);
76
77#endif /* __ASM_GENERIC_CHECKSUM_H */