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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * include/asm-v850/checksum.h -- Checksum ops
3 *
4 * Copyright (C) 2001 NEC Corporation
5 * Copyright (C) 2001 Miles Bader <miles@gnu.org>
6 *
7 * This file is subject to the terms and conditions of the GNU General
8 * Public License. See the file COPYING in the main directory of this
9 * archive for more details.
10 *
11 * Written by Miles Bader <miles@gnu.org>
12 */
13
14#ifndef __V850_CHECKSUM_H__
15#define __V850_CHECKSUM_H__
16
17/*
18 * computes the checksum of a memory block at buff, length len,
19 * and adds in "sum" (32-bit)
20 *
21 * returns a 32-bit number suitable for feeding into itself
22 * or csum_tcpudp_magic
23 *
24 * this function must be called with even lengths, except
25 * for the last fragment, which may be odd
26 *
27 * it's best to have buff aligned on a 32-bit boundary
28 */
29extern unsigned int csum_partial (const unsigned char * buff, int len,
30 unsigned int sum);
31
32/*
33 * the same as csum_partial, but copies from src while it
34 * checksums
35 *
36 * here even more important to align src and dst on a 32-bit (or even
37 * better 64-bit) boundary
38 */
39extern unsigned csum_partial_copy (const char *src, char *dst, int len,
40 unsigned sum);
41
42
43/*
44 * the same as csum_partial_copy, but copies from user space.
45 *
46 * here even more important to align src and dst on a 32-bit (or even
47 * better 64-bit) boundary
48 */
49extern unsigned csum_partial_copy_from_user (const char *src, char *dst,
50 int len, unsigned sum,
51 int *csum_err);
52
53#define csum_partial_copy_nocheck(src, dst, len, sum) \
54 csum_partial_copy ((src), (dst), (len), (sum))
55
56unsigned short ip_fast_csum (unsigned char *iph, unsigned int ihl);
57
58/*
59 * Fold a partial checksum
60 */
61static inline unsigned int csum_fold (unsigned long sum)
62{
63 unsigned int result;
64 /*
65 %0 %1
66 hsw %1, %0 H L L H
67 add %1, %0 H L H+L+C H+L
68 */
69 asm ("hsw %1, %0; add %1, %0" : "=&r" (result) : "r" (sum));
70 return (~result) >> 16;
71}
72
73
74/*
75 * computes the checksum of the TCP/UDP pseudo-header
76 * returns a 16-bit checksum, already complemented
77 */
78static inline unsigned int
79csum_tcpudp_nofold (unsigned long saddr, unsigned long daddr,
80 unsigned short len,
81 unsigned short proto, unsigned int sum)
82{
83 int __carry;
84 __asm__ ("add %2, %0;"
85 "setf c, %1;"
86 "add %1, %0;"
87 "add %3, %0;"
88 "setf c, %1;"
89 "add %1, %0;"
90 "add %4, %0;"
91 "setf c, %1;"
92 "add %1, %0"
93 : "=&r" (sum), "=&r" (__carry)
94 : "r" (daddr), "r" (saddr),
95 "r" (ntohs (len) + (proto << 8)),
96 "0" (sum));
97 return sum;
98}
99
100static inline unsigned short int
101csum_tcpudp_magic (unsigned long saddr, unsigned long daddr,
102 unsigned short len,
103 unsigned short proto, unsigned int sum)
104{
105 return csum_fold (csum_tcpudp_nofold (saddr, daddr, len, proto, sum));
106}
107
108/*
109 * this routine is used for miscellaneous IP-like checksums, mainly
110 * in icmp.c
111 */
112extern unsigned short ip_compute_csum (const unsigned char * buff, int len);
113
114
115#endif /* __V850_CHECKSUM_H__ */