aboutsummaryrefslogtreecommitdiffstats
path: root/include/asm-mips/checksum.h
blob: c25cc92b99508b4886aa4e021beafda484926d09 (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
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1995, 96, 97, 98, 99, 2001 by Ralf Baechle
 * Copyright (C) 1999 Silicon Graphics, Inc.
 * Copyright (C) 2001 Thiemo Seufer.
 * Copyright (C) 2002 Maciej W. Rozycki
 */
#ifndef _ASM_CHECKSUM_H
#define _ASM_CHECKSUM_H

#include <linux/config.h>
#include <linux/in6.h>

#include <asm/uaccess.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
 */
unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum);

/*
 * this is a new version of the above that records errors it finds in *errp,
 * but continues and zeros the rest of the buffer.
 */
unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst, int len,
                                         unsigned int sum, int *errp);

/*
 * Copy and checksum to user
 */
#define HAVE_CSUM_COPY_USER
static inline unsigned int csum_and_copy_to_user (const unsigned char *src,
						  unsigned char __user *dst,
						  int len, int sum,
						  int *err_ptr)
{
	might_sleep();
	sum = csum_partial(src, len, sum);

	if (copy_to_user(dst, src, len)) {
		*err_ptr = -EFAULT;
		return -1;
	}

	return sum;
}

/*
 * the same as csum_partial, but copies from user space (but on MIPS
 * we have just one address space, so this is identical to the above)
 */
unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst,
				       int len, unsigned int sum);

/*
 *	Fold a partial checksum without adding pseudo headers
 */
static inline unsigned short int csum_fold(unsigned int sum)
{
	__asm__(
	".set\tnoat\t\t\t# csum_fold\n\t"
	"sll\t$1,%0,16\n\t"
	"addu\t%0,$1\n\t"
	"sltu\t$1,%0,$1\n\t"
	"srl\t%0,%0,16\n\t"
	"addu\t%0,$1\n\t"
	"xori\t%0,0xffff\n\t"
	".set\tat"
	: "=r" (sum)
	: "0" (sum));

	return sum;
}

/*
 *	This is a version of ip_compute_csum() optimized for IP headers,
 *	which always checksum on 4 octet boundaries.
 *
 *	By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
 *	Arnt Gulbrandsen.
 */
static inline unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl)
{
	unsigned int *word = (unsigned int *) iph;
	unsigned int *stop = word + ihl;
	unsigned int csum;
	int carry;

	csum = word[0];
	csum += word[1];
	carry = (csum < word[1]);
	csum += carry;

	csum += word[2];
	carry = (csum < word[2]);
	csum += carry;

	csum += word[3];
	carry = (csum < word[3]);
	csum += carry;

	word += 4;
	do {
		csum += *word;
		carry = (csum < *word);
		csum += carry;
		word++;
	} while (word != stop);

	return csum_fold(csum);
}

static inline unsigned int csum_tcpudp_nofold(unsigned long saddr,
	unsigned long daddr, unsigned short len, unsigned short proto,
	unsigned int sum)
{
	__asm__(
	".set\tnoat\t\t\t# csum_tcpudp_nofold\n\t"
#ifdef CONFIG_MIPS32
	"addu\t%0, %2\n\t"
	"sltu\t$1, %0, %2\n\t"
	"addu\t%0, $1\n\t"

	"addu\t%0, %3\n\t"
	"sltu\t$1, %0, %3\n\t"
	"addu\t%0, $1\n\t"

	"addu\t%0, %4\n\t"
	"sltu\t$1, %0, %4\n\t"
	"addu\t%0, $1\n\t"
#endif
#ifdef CONFIG_MIPS64
	"daddu\t%0, %2\n\t"
	"daddu\t%0, %3\n\t"
	"daddu\t%0, %4\n\t"
	"dsll32\t$1, %0, 0\n\t"
	"daddu\t%0, $1\n\t"
	"dsrl32\t%0, %0, 0\n\t"
#endif
	".set\tat"
	: "=r" (sum)
	: "0" (daddr), "r"(saddr),
#ifdef __MIPSEL__
	  "r" (((unsigned long)htons(len)<<16) + proto*256),
#else
	  "r" (((unsigned long)(proto)<<16) + len),
#endif
	  "r" (sum));

	return sum;
}

/*
 * computes the checksum of the TCP/UDP pseudo-header
 * returns a 16-bit checksum, already complemented
 */
static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
						   unsigned long daddr,
						   unsigned short len,
						   unsigned short proto,
						   unsigned int 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 unsigned short ip_compute_csum(unsigned char * buff, int len)
{
	return csum_fold(csum_partial(buff, len, 0));
}

#define _HAVE_ARCH_IPV6_CSUM
static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
						     struct in6_addr *daddr,
						     __u32 len,
						     unsigned short proto,
						     unsigned int sum)
{
	__asm__(
	".set\tpush\t\t\t# csum_ipv6_magic\n\t"
	".set\tnoreorder\n\t"
	".set\tnoat\n\t"
	"addu\t%0, %5\t\t\t# proto (long in network byte order)\n\t"
	"sltu\t$1, %0, %5\n\t"
	"addu\t%0, $1\n\t"

	"addu\t%0, %6\t\t\t# csum\n\t"
	"sltu\t$1, %0, %6\n\t"
	"lw\t%1, 0(%2)\t\t\t# four words source address\n\t"
	"addu\t%0, $1\n\t"
	"addu\t%0, %1\n\t"
	"sltu\t$1, %0, %1\n\t"

	"lw\t%1, 4(%2)\n\t"
	"addu\t%0, $1\n\t"
	"addu\t%0, %1\n\t"
	"sltu\t$1, %0, %1\n\t"

	"lw\t%1, 8(%2)\n\t"
	"addu\t%0, $1\n\t"
	"addu\t%0, %1\n\t"
	"sltu\t$1, %0, %1\n\t"

	"lw\t%1, 12(%2)\n\t"
	"addu\t%0, $1\n\t"
	"addu\t%0, %1\n\t"
	"sltu\t$1, %0, %1\n\t"

	"lw\t%1, 0(%3)\n\t"
	"addu\t%0, $1\n\t"
	"addu\t%0, %1\n\t"
	"sltu\t$1, %0, %1\n\t"

	"lw\t%1, 4(%3)\n\t"
	"addu\t%0, $1\n\t"
	"addu\t%0, %1\n\t"
	"sltu\t$1, %0, %1\n\t"

	"lw\t%1, 8(%3)\n\t"
	"addu\t%0, $1\n\t"
	"addu\t%0, %1\n\t"
	"sltu\t$1, %0, %1\n\t"

	"lw\t%1, 12(%3)\n\t"
	"addu\t%0, $1\n\t"
	"addu\t%0, %1\n\t"
	"sltu\t$1, %0, %1\n\t"

	"addu\t%0, $1\t\t\t# Add final carry\n\t"
	".set\tpop"
	: "=r" (sum), "=r" (proto)
	: "r" (saddr), "r" (daddr),
	  "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));

	return csum_fold(sum);
}

#endif /* _ASM_CHECKSUM_H */