1#ifndef _METAG_CHECKSUM_H
2#define _METAG_CHECKSUM_H
3
4/*
5 * computes the checksum of a memory block at buff, length len,
6 * and adds in "sum" (32-bit)
7 *
8 * returns a 32-bit number suitable for feeding into itself
9 * or csum_tcpudp_magic
10 *
11 * this function must be called with even lengths, except
12 * for the last fragment, which may be odd
13 *
14 * it's best to have buff aligned on a 32-bit boundary
15 */
16extern __wsum csum_partial(const void *buff, int len, __wsum sum);
17
18/*
19 * the same as csum_partial, but copies from src while it
20 * checksums
21 *
22 * here even more important to align src and dst on a 32-bit (or even
23 * better 64-bit) boundary
24 */
25extern __wsum csum_partial_copy(const void *src, void *dst, int len,
26				__wsum sum);
27
28/*
29 * the same as csum_partial_copy, but copies from user space.
30 *
31 * here even more important to align src and dst on a 32-bit (or even
32 * better 64-bit) boundary
33 */
34extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
35					int len, __wsum sum, int *csum_err);
36
37#define csum_partial_copy_nocheck(src, dst, len, sum)	\
38	csum_partial_copy((src), (dst), (len), (sum))
39
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
51/*
52 * This is a version of ip_compute_csum() optimized for IP headers,
53 * which always checksum on 4 octet boundaries.
54 */
55extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
56
57/*
58 * computes the checksum of the TCP/UDP pseudo-header
59 * returns a 16-bit checksum, already complemented
60 */
61static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
62					unsigned short len,
63					unsigned short proto,
64					__wsum sum)
65{
66	unsigned long len_proto = (proto + len) << 8;
67	asm ("ADDS   %0, %0, %1\n"
68	     "ADDCS  %0, %0, #1\n"
69	     "ADDS   %0, %0, %2\n"
70	     "ADDCS  %0, %0, #1\n"
71	     "ADDS   %0, %0, %3\n"
72	     "ADDCS  %0, %0, #1\n"
73	     : "=d" (sum)
74	     : "d" (daddr), "d" (saddr), "d" (len_proto),
75	       "0" (sum)
76	     : "cc");
77	return sum;
78}
79
80static inline __sum16
81csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
82		  unsigned short proto, __wsum sum)
83{
84	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
85}
86
87/*
88 * this routine is used for miscellaneous IP-like checksums, mainly
89 * in icmp.c
90 */
91extern __sum16 ip_compute_csum(const void *buff, int len);
92
93#endif /* _METAG_CHECKSUM_H */
94