xref: /linux/arch/mips/include/asm/checksum.h (revision 26fbb4c8c7c3ee9a4c3b4de555a8587b5a19154e)
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 1995, 96, 97, 98, 99, 2001 by Ralf Baechle
7  * Copyright (C) 1999 Silicon Graphics, Inc.
8  * Copyright (C) 2001 Thiemo Seufer.
9  * Copyright (C) 2002 Maciej W. Rozycki
10  * Copyright (C) 2014 Imagination Technologies Ltd.
11  */
12 #ifndef _ASM_CHECKSUM_H
13 #define _ASM_CHECKSUM_H
14 
15 #ifdef CONFIG_GENERIC_CSUM
16 #include <asm-generic/checksum.h>
17 #else
18 
19 #include <linux/in6.h>
20 
21 #include <linux/uaccess.h>
22 
23 /*
24  * computes the checksum of a memory block at buff, length len,
25  * and adds in "sum" (32-bit)
26  *
27  * returns a 32-bit number suitable for feeding into itself
28  * or csum_tcpudp_magic
29  *
30  * this function must be called with even lengths, except
31  * for the last fragment, which may be odd
32  *
33  * it's best to have buff aligned on a 32-bit boundary
34  */
35 __wsum csum_partial(const void *buff, int len, __wsum sum);
36 
37 __wsum __csum_partial_copy_from_user(const void __user *src, void *dst, int len);
38 __wsum __csum_partial_copy_to_user(const void *src, void __user *dst, int len);
39 
40 #define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
41 static inline
42 __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len)
43 {
44 	might_fault();
45 	if (!access_ok(src, len))
46 		return 0;
47 	return __csum_partial_copy_from_user(src, dst, len);
48 }
49 
50 /*
51  * Copy and checksum to user
52  */
53 #define HAVE_CSUM_COPY_USER
54 static inline
55 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
56 {
57 	might_fault();
58 	if (!access_ok(dst, len))
59 		return 0;
60 	return __csum_partial_copy_to_user(src, dst, len);
61 }
62 
63 /*
64  * the same as csum_partial, but copies from user space (but on MIPS
65  * we have just one address space, so this is identical to the above)
66  */
67 #define _HAVE_ARCH_CSUM_AND_COPY
68 __wsum __csum_partial_copy_nocheck(const void *src, void *dst, int len);
69 static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
70 {
71 	return __csum_partial_copy_nocheck(src, dst, len);
72 }
73 
74 /*
75  *	Fold a partial checksum without adding pseudo headers
76  */
77 static inline __sum16 csum_fold(__wsum csum)
78 {
79 	u32 sum = (__force u32)csum;
80 
81 	sum += (sum << 16);
82 	csum = (__force __wsum)(sum < (__force u32)csum);
83 	sum >>= 16;
84 	sum += (__force u32)csum;
85 
86 	return (__force __sum16)~sum;
87 }
88 #define csum_fold csum_fold
89 
90 /*
91  *	This is a version of ip_compute_csum() optimized for IP headers,
92  *	which always checksum on 4 octet boundaries.
93  *
94  *	By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
95  *	Arnt Gulbrandsen.
96  */
97 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
98 {
99 	const unsigned int *word = iph;
100 	const unsigned int *stop = word + ihl;
101 	unsigned int csum;
102 	int carry;
103 
104 	csum = word[0];
105 	csum += word[1];
106 	carry = (csum < word[1]);
107 	csum += carry;
108 
109 	csum += word[2];
110 	carry = (csum < word[2]);
111 	csum += carry;
112 
113 	csum += word[3];
114 	carry = (csum < word[3]);
115 	csum += carry;
116 
117 	word += 4;
118 	do {
119 		csum += *word;
120 		carry = (csum < *word);
121 		csum += carry;
122 		word++;
123 	} while (word != stop);
124 
125 	return csum_fold(csum);
126 }
127 #define ip_fast_csum ip_fast_csum
128 
129 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
130 					__u32 len, __u8 proto,
131 					__wsum sum)
132 {
133 	__asm__(
134 	"	.set	push		# csum_tcpudp_nofold\n"
135 	"	.set	noat		\n"
136 #ifdef CONFIG_32BIT
137 	"	addu	%0, %2		\n"
138 	"	sltu	$1, %0, %2	\n"
139 	"	addu	%0, $1		\n"
140 
141 	"	addu	%0, %3		\n"
142 	"	sltu	$1, %0, %3	\n"
143 	"	addu	%0, $1		\n"
144 
145 	"	addu	%0, %4		\n"
146 	"	sltu	$1, %0, %4	\n"
147 	"	addu	%0, $1		\n"
148 #endif
149 #ifdef CONFIG_64BIT
150 	"	daddu	%0, %2		\n"
151 	"	daddu	%0, %3		\n"
152 	"	daddu	%0, %4		\n"
153 	"	dsll32	$1, %0, 0	\n"
154 	"	daddu	%0, $1		\n"
155 	"	sltu	$1, %0, $1	\n"
156 	"	dsra32	%0, %0, 0	\n"
157 	"	addu	%0, $1		\n"
158 #endif
159 	"	.set	pop"
160 	: "=r" (sum)
161 	: "0" ((__force unsigned long)daddr),
162 	  "r" ((__force unsigned long)saddr),
163 #ifdef __MIPSEL__
164 	  "r" ((proto + len) << 8),
165 #else
166 	  "r" (proto + len),
167 #endif
168 	  "r" ((__force unsigned long)sum));
169 
170 	return sum;
171 }
172 #define csum_tcpudp_nofold csum_tcpudp_nofold
173 
174 /*
175  * this routine is used for miscellaneous IP-like checksums, mainly
176  * in icmp.c
177  */
178 static inline __sum16 ip_compute_csum(const void *buff, int len)
179 {
180 	return csum_fold(csum_partial(buff, len, 0));
181 }
182 
183 #define _HAVE_ARCH_IPV6_CSUM
184 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
185 					  const struct in6_addr *daddr,
186 					  __u32 len, __u8 proto,
187 					  __wsum sum)
188 {
189 	__wsum tmp;
190 
191 	__asm__(
192 	"	.set	push		# csum_ipv6_magic\n"
193 	"	.set	noreorder	\n"
194 	"	.set	noat		\n"
195 	"	addu	%0, %5		# proto (long in network byte order)\n"
196 	"	sltu	$1, %0, %5	\n"
197 	"	addu	%0, $1		\n"
198 
199 	"	addu	%0, %6		# csum\n"
200 	"	sltu	$1, %0, %6	\n"
201 	"	lw	%1, 0(%2)	# four words source address\n"
202 	"	addu	%0, $1		\n"
203 	"	addu	%0, %1		\n"
204 	"	sltu	$1, %0, %1	\n"
205 
206 	"	lw	%1, 4(%2)	\n"
207 	"	addu	%0, $1		\n"
208 	"	addu	%0, %1		\n"
209 	"	sltu	$1, %0, %1	\n"
210 
211 	"	lw	%1, 8(%2)	\n"
212 	"	addu	%0, $1		\n"
213 	"	addu	%0, %1		\n"
214 	"	sltu	$1, %0, %1	\n"
215 
216 	"	lw	%1, 12(%2)	\n"
217 	"	addu	%0, $1		\n"
218 	"	addu	%0, %1		\n"
219 	"	sltu	$1, %0, %1	\n"
220 
221 	"	lw	%1, 0(%3)	\n"
222 	"	addu	%0, $1		\n"
223 	"	addu	%0, %1		\n"
224 	"	sltu	$1, %0, %1	\n"
225 
226 	"	lw	%1, 4(%3)	\n"
227 	"	addu	%0, $1		\n"
228 	"	addu	%0, %1		\n"
229 	"	sltu	$1, %0, %1	\n"
230 
231 	"	lw	%1, 8(%3)	\n"
232 	"	addu	%0, $1		\n"
233 	"	addu	%0, %1		\n"
234 	"	sltu	$1, %0, %1	\n"
235 
236 	"	lw	%1, 12(%3)	\n"
237 	"	addu	%0, $1		\n"
238 	"	addu	%0, %1		\n"
239 	"	sltu	$1, %0, %1	\n"
240 
241 	"	addu	%0, $1		# Add final carry\n"
242 	"	.set	pop"
243 	: "=&r" (sum), "=&r" (tmp)
244 	: "r" (saddr), "r" (daddr),
245 	  "0" (htonl(len)), "r" (htonl(proto)), "r" (sum));
246 
247 	return csum_fold(sum);
248 }
249 
250 #include <asm-generic/checksum.h>
251 #endif /* CONFIG_GENERIC_CSUM */
252 
253 #endif /* _ASM_CHECKSUM_H */
254