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1/* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */
2
3#ifndef _CRIS_CHECKSUM_H
4#define _CRIS_CHECKSUM_H
5
6#include <arch/checksum.h>
7
8/*
9 * computes the checksum of a memory block at buff, length len,
10 * and adds in "sum" (32-bit)
11 *
12 * returns a 32-bit number suitable for feeding into itself
13 * or csum_tcpudp_magic
14 *
15 * this function must be called with even lengths, except
16 * for the last fragment, which may be odd
17 *
18 * it's best to have buff aligned on a 32-bit boundary
19 */
20__wsum csum_partial(const void *buff, int len, __wsum sum);
21
22/*
23 * the same as csum_partial, but copies from src while it
24 * checksums
25 *
26 * here even more important to align src and dst on a 32-bit (or even
27 * better 64-bit) boundary
28 */
29
30__wsum csum_partial_copy_nocheck(const void *src, void *dst,
31 int len, __wsum sum);
32
33/*
34 * Fold a partial checksum into a word
35 */
36
37static inline __sum16 csum_fold(__wsum csum)
38{
39 u32 sum = (__force u32)csum;
40 sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
41 sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
42 return (__force __sum16)~sum;
43}
44
45extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
46 int len, __wsum sum,
47 int *errptr);
48
49/*
50 * This is a version of ip_compute_csum() optimized for IP headers,
51 * which always checksum on 4 octet boundaries.
52 *
53 */
54
55static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
56{
57 return csum_fold(csum_partial(iph, ihl * 4, 0));
58}
59
60/*
61 * computes the checksum of the TCP/UDP pseudo-header
62 * returns a 16-bit checksum, already complemented
63 */
64
65static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
66 unsigned short len,
67 unsigned short proto,
68 __wsum sum)
69{
70 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
71}
72
73/*
74 * this routine is used for miscellaneous IP-like checksums, mainly
75 * in icmp.c
76 */
77
78static inline __sum16 ip_compute_csum(const void *buff, int len)
79{
80 return csum_fold (csum_partial(buff, len, 0));
81}
82
83#endif