1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _METAG_CHECKSUM_H
3 #define _METAG_CHECKSUM_H
6 * computes the checksum of a memory block at buff, length len,
7 * and adds in "sum" (32-bit)
9 * returns a 32-bit number suitable for feeding into itself
10 * or csum_tcpudp_magic
12 * this function must be called with even lengths, except
13 * for the last fragment, which may be odd
15 * it's best to have buff aligned on a 32-bit boundary
17 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
20 * the same as csum_partial, but copies from src while it
23 * here even more important to align src and dst on a 32-bit (or even
24 * better 64-bit) boundary
26 extern __wsum csum_partial_copy(const void *src, void *dst, int len,
30 * the same as csum_partial_copy, but copies from user space.
32 * here even more important to align src and dst on a 32-bit (or even
33 * better 64-bit) boundary
35 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
36 int len, __wsum sum, int *csum_err);
38 #define csum_partial_copy_nocheck(src, dst, len, sum) \
39 csum_partial_copy((src), (dst), (len), (sum))
42 * Fold a partial checksum
44 static inline __sum16 csum_fold(__wsum csum)
46 u32 sum = (__force u32)csum;
47 sum = (sum & 0xffff) + (sum >> 16);
48 sum = (sum & 0xffff) + (sum >> 16);
49 return (__force __sum16)~sum;
53 * This is a version of ip_compute_csum() optimized for IP headers,
54 * which always checksum on 4 octet boundaries.
56 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
59 * computes the checksum of the TCP/UDP pseudo-header
60 * returns a 16-bit checksum, already complemented
62 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
63 __u32 len, __u8 proto,
66 unsigned long len_proto = (proto + len) << 8;
67 asm ("ADDS %0, %0, %1\n"
74 : "d" (daddr), "d" (saddr), "d" (len_proto),
81 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
82 __u8 proto, __wsum sum)
84 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
88 * this routine is used for miscellaneous IP-like checksums, mainly
91 extern __sum16 ip_compute_csum(const void *buff, int len);
93 #endif /* _METAG_CHECKSUM_H */