1 #ifndef _METAG_CHECKSUM_H
2 #define _METAG_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,
29 * the same as csum_partial_copy, but copies from user space.
31 * here even more important to align src and dst on a 32-bit (or even
32 * better 64-bit) boundary
34 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
35 int len, __wsum sum, int *csum_err);
37 #define csum_partial_copy_nocheck(src, dst, len, sum) \
38 csum_partial_copy((src), (dst), (len), (sum))
41 * Fold a partial checksum
43 static inline __sum16 csum_fold(__wsum csum)
45 u32 sum = (__force u32)csum;
46 sum = (sum & 0xffff) + (sum >> 16);
47 sum = (sum & 0xffff) + (sum >> 16);
48 return (__force __sum16)~sum;
52 * This is a version of ip_compute_csum() optimized for IP headers,
53 * which always checksum on 4 octet boundaries.
55 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
58 * computes the checksum of the TCP/UDP pseudo-header
59 * returns a 16-bit checksum, already complemented
61 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
62 __u32 len, __u8 proto,
65 unsigned long len_proto = (proto + len) << 8;
66 asm ("ADDS %0, %0, %1\n"
73 : "d" (daddr), "d" (saddr), "d" (len_proto),
80 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
81 __u8 proto, __wsum sum)
83 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
87 * this routine is used for miscellaneous IP-like checksums, mainly
90 extern __sum16 ip_compute_csum(const void *buff, int len);
92 #endif /* _METAG_CHECKSUM_H */