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 <asm/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_kernel(const void *src, void *dst,
38				  int len, __wsum sum, int *err_ptr);
39
40__wsum __csum_partial_copy_from_user(const void *src, void *dst,
41				     int len, __wsum sum, int *err_ptr);
42__wsum __csum_partial_copy_to_user(const void *src, void *dst,
43				   int len, __wsum sum, int *err_ptr);
44/*
45 * this is a new version of the above that records errors it finds in *errp,
46 * but continues and zeros the rest of the buffer.
47 */
48static inline
49__wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len,
50				   __wsum sum, int *err_ptr)
51{
52	might_fault();
53	if (segment_eq(get_fs(), get_ds()))
54		return __csum_partial_copy_kernel((__force void *)src, dst,
55						  len, sum, err_ptr);
56	else
57		return __csum_partial_copy_from_user((__force void *)src, dst,
58						     len, sum, err_ptr);
59}
60
61#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
62static inline
63__wsum csum_and_copy_from_user(const void __user *src, void *dst,
64			       int len, __wsum sum, int *err_ptr)
65{
66	if (access_ok(VERIFY_READ, src, len))
67		return csum_partial_copy_from_user(src, dst, len, sum,
68						   err_ptr);
69	if (len)
70		*err_ptr = -EFAULT;
71
72	return sum;
73}
74
75/*
76 * Copy and checksum to user
77 */
78#define HAVE_CSUM_COPY_USER
79static inline
80__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
81			     __wsum sum, int *err_ptr)
82{
83	might_fault();
84	if (access_ok(VERIFY_WRITE, dst, len)) {
85		if (segment_eq(get_fs(), get_ds()))
86			return __csum_partial_copy_kernel(src,
87							  (__force void *)dst,
88							  len, sum, err_ptr);
89		else
90			return __csum_partial_copy_to_user(src,
91							   (__force void *)dst,
92							   len, sum, err_ptr);
93	}
94	if (len)
95		*err_ptr = -EFAULT;
96
97	return (__force __wsum)-1; /* invalid checksum */
98}
99
100/*
101 * the same as csum_partial, but copies from user space (but on MIPS
102 * we have just one address space, so this is identical to the above)
103 */
104__wsum csum_partial_copy_nocheck(const void *src, void *dst,
105				       int len, __wsum sum);
106#define csum_partial_copy_nocheck csum_partial_copy_nocheck
107
108/*
109 *	Fold a partial checksum without adding pseudo headers
110 */
111static inline __sum16 csum_fold(__wsum csum)
112{
113	u32 sum = (__force u32)csum;;
114
115	sum += (sum << 16);
116	csum = (sum < csum);
117	sum >>= 16;
118	sum += csum;
119
120	return (__force __sum16)~sum;
121}
122#define csum_fold csum_fold
123
124/*
125 *	This is a version of ip_compute_csum() optimized for IP headers,
126 *	which always checksum on 4 octet boundaries.
127 *
128 *	By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
129 *	Arnt Gulbrandsen.
130 */
131static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
132{
133	const unsigned int *word = iph;
134	const unsigned int *stop = word + ihl;
135	unsigned int csum;
136	int carry;
137
138	csum = word[0];
139	csum += word[1];
140	carry = (csum < word[1]);
141	csum += carry;
142
143	csum += word[2];
144	carry = (csum < word[2]);
145	csum += carry;
146
147	csum += word[3];
148	carry = (csum < word[3]);
149	csum += carry;
150
151	word += 4;
152	do {
153		csum += *word;
154		carry = (csum < *word);
155		csum += carry;
156		word++;
157	} while (word != stop);
158
159	return csum_fold(csum);
160}
161#define ip_fast_csum ip_fast_csum
162
163static inline __wsum csum_tcpudp_nofold(__be32 saddr,
164	__be32 daddr, unsigned short len, unsigned short proto,
165	__wsum sum)
166{
167	__asm__(
168	"	.set	push		# csum_tcpudp_nofold\n"
169	"	.set	noat		\n"
170#ifdef CONFIG_32BIT
171	"	addu	%0, %2		\n"
172	"	sltu	$1, %0, %2	\n"
173	"	addu	%0, $1		\n"
174
175	"	addu	%0, %3		\n"
176	"	sltu	$1, %0, %3	\n"
177	"	addu	%0, $1		\n"
178
179	"	addu	%0, %4		\n"
180	"	sltu	$1, %0, %4	\n"
181	"	addu	%0, $1		\n"
182#endif
183#ifdef CONFIG_64BIT
184	"	daddu	%0, %2		\n"
185	"	daddu	%0, %3		\n"
186	"	daddu	%0, %4		\n"
187	"	dsll32	$1, %0, 0	\n"
188	"	daddu	%0, $1		\n"
189	"	dsra32	%0, %0, 0	\n"
190#endif
191	"	.set	pop"
192	: "=r" (sum)
193	: "0" ((__force unsigned long)daddr),
194	  "r" ((__force unsigned long)saddr),
195#ifdef __MIPSEL__
196	  "r" ((proto + len) << 8),
197#else
198	  "r" (proto + len),
199#endif
200	  "r" ((__force unsigned long)sum));
201
202	return sum;
203}
204#define csum_tcpudp_nofold csum_tcpudp_nofold
205
206/*
207 * this routine is used for miscellaneous IP-like checksums, mainly
208 * in icmp.c
209 */
210static inline __sum16 ip_compute_csum(const void *buff, int len)
211{
212	return csum_fold(csum_partial(buff, len, 0));
213}
214
215#define _HAVE_ARCH_IPV6_CSUM
216static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
217					  const struct in6_addr *daddr,
218					  __u32 len, unsigned short proto,
219					  __wsum sum)
220{
221	__wsum tmp;
222
223	__asm__(
224	"	.set	push		# csum_ipv6_magic\n"
225	"	.set	noreorder	\n"
226	"	.set	noat		\n"
227	"	addu	%0, %5		# proto (long in network byte order)\n"
228	"	sltu	$1, %0, %5	\n"
229	"	addu	%0, $1		\n"
230
231	"	addu	%0, %6		# csum\n"
232	"	sltu	$1, %0, %6	\n"
233	"	lw	%1, 0(%2)	# four words source address\n"
234	"	addu	%0, $1		\n"
235	"	addu	%0, %1		\n"
236	"	sltu	$1, %0, %1	\n"
237
238	"	lw	%1, 4(%2)	\n"
239	"	addu	%0, $1		\n"
240	"	addu	%0, %1		\n"
241	"	sltu	$1, %0, %1	\n"
242
243	"	lw	%1, 8(%2)	\n"
244	"	addu	%0, $1		\n"
245	"	addu	%0, %1		\n"
246	"	sltu	$1, %0, %1	\n"
247
248	"	lw	%1, 12(%2)	\n"
249	"	addu	%0, $1		\n"
250	"	addu	%0, %1		\n"
251	"	sltu	$1, %0, %1	\n"
252
253	"	lw	%1, 0(%3)	\n"
254	"	addu	%0, $1		\n"
255	"	addu	%0, %1		\n"
256	"	sltu	$1, %0, %1	\n"
257
258	"	lw	%1, 4(%3)	\n"
259	"	addu	%0, $1		\n"
260	"	addu	%0, %1		\n"
261	"	sltu	$1, %0, %1	\n"
262
263	"	lw	%1, 8(%3)	\n"
264	"	addu	%0, $1		\n"
265	"	addu	%0, %1		\n"
266	"	sltu	$1, %0, %1	\n"
267
268	"	lw	%1, 12(%3)	\n"
269	"	addu	%0, $1		\n"
270	"	addu	%0, %1		\n"
271	"	sltu	$1, %0, %1	\n"
272
273	"	addu	%0, $1		# Add final carry\n"
274	"	.set	pop"
275	: "=&r" (sum), "=&r" (tmp)
276	: "r" (saddr), "r" (daddr),
277	  "0" (htonl(len)), "r" (htonl(proto)), "r" (sum));
278
279	return csum_fold(sum);
280}
281
282#include <asm-generic/checksum.h>
283#endif /* CONFIG_GENERIC_CSUM */
284
285#endif /* _ASM_CHECKSUM_H */
286