aboutsummaryrefslogtreecommitdiffstats
path: root/arch/avr32/include/asm/checksum.h
blob: 4ddbfd2486af06412b32e7cf66af54ce1942d9e8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
/*
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#ifndef __ASM_AVR32_CHECKSUM_H
#define __ASM_AVR32_CHECKSUM_H

/*
 * computes the checksum of a memory block at buff, length len,
 * and adds in "sum" (32-bit)
 *
 * returns a 32-bit number suitable for feeding into itself
 * or csum_tcpudp_magic
 *
 * this function must be called with even lengths, except
 * for the last fragment, which may be odd
 *
 * it's best to have buff aligned on a 32-bit boundary
 */
__wsum csum_partial(const void *buff, int len, __wsum sum);

/*
 * the same as csum_partial, but copies from src while it
 * checksums, and handles user-space pointer exceptions correctly, when needed.
 *
 * here even more important to align src and dst on a 32-bit (or even
 * better 64-bit) boundary
 */
__wsum csum_partial_copy_generic(const void *src, void *dst, int len,
				       __wsum sum, int *src_err_ptr,
				       int *dst_err_ptr);

/*
 *	Note: when you get a NULL pointer exception here this means someone
 *	passed in an incorrect kernel address to one of these functions.
 *
 *	If you use these functions directly please don't forget the
 *	access_ok().
 */
static inline
__wsum csum_partial_copy_nocheck(const void *src, void *dst,
				       int len, __wsum sum)
{
	return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
}

static inline
__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
					  int len, __wsum sum, int *err_ptr)
{
	return csum_partial_copy_generic((const void __force *)src, dst, len,
					 sum, err_ptr, NULL);
}

/*
 *	This is a version of ip_compute_csum() optimized for IP headers,
 *	which always checksum on 4 octet boundaries.
 */
static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
{
	unsigned int sum, tmp;

	__asm__ __volatile__(
		"	ld.w	%0, %1++\n"
		"	ld.w	%3, %1++\n"
		"	sub	%2, 4\n"
		"	add	%0, %3\n"
		"	ld.w	%3, %1++\n"
		"	adc	%0, %0, %3\n"
		"	ld.w	%3, %1++\n"
		"	adc	%0, %0, %3\n"
		"	acr	%0\n"
		"1:	ld.w	%3, %1++\n"
		"	add	%0, %3\n"
		"	acr	%0\n"
		"	sub	%2, 1\n"
		"	brne	1b\n"
		"	lsl	%3, %0, 16\n"
		"	andl	%0, 0\n"
		"	mov	%2, 0xffff\n"
		"	add	%0, %3\n"
		"	adc	%0, %0, %2\n"
		"	com	%0\n"
		"	lsr	%0, 16\n"
		: "=r"(sum), "=r"(iph), "=r"(ihl), "=r"(tmp)
		: "1"(iph), "2"(ihl)
		: "memory", "cc");
	return (__force __sum16)sum;
}

/*
 *	Fold a partial checksum
 */

static inline __sum16 csum_fold(__wsum sum)
{
	unsigned int tmp;

	asm("	bfextu	%1, %0, 0, 16\n"
	    "	lsr	%0, 16\n"
	    "	add	%0, %1\n"
	    "	bfextu	%1, %0, 16, 16\n"
	    "	add	%0, %1"
	    : "=&r"(sum), "=&r"(tmp)
	    : "0"(sum));

	return (__force __sum16)~sum;
}

static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
					       unsigned short len,
					       unsigned short proto,
					       __wsum sum)
{
	asm("	add	%0, %1\n"
	    "	adc	%0, %0, %2\n"
	    "	adc	%0, %0, %3\n"
	    "	acr	%0"
	    : "=r"(sum)
	    : "r"(daddr), "r"(saddr), "r"(len + proto),
	      "0"(sum)
	    : "cc");

	return sum;
}

/*
 * computes the checksum of the TCP/UDP pseudo-header
 * returns a 16-bit checksum, already complemented
 */
static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
						   unsigned short len,
						   unsigned short proto,
						   __wsum sum)
{
	return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
}

/*
 * this routine is used for miscellaneous IP-like checksums, mainly
 * in icmp.c
 */

static inline __sum16 ip_compute_csum(const void *buff, int len)
{
    return csum_fold(csum_partial(buff, len, 0));
}

#endif /* __ASM_AVR32_CHECKSUM_H */