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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_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 (uaccess_kernel())
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(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(dst, len)) {
85 if (uaccess_kernel())
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, __be32 daddr,
164 __u32 len, __u8 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 " sltu $1, %0, $1 \n"
190 " dsra32 %0, %0, 0 \n"
191 " addu %0, $1 \n"
192#endif
193 " .set pop"
194 : "=r" (sum)
195 : "0" ((__force unsigned long)daddr),
196 "r" ((__force unsigned long)saddr),
197#ifdef __MIPSEL__
198 "r" ((proto + len) << 8),
199#else
200 "r" (proto + len),
201#endif
202 "r" ((__force unsigned long)sum));
203
204 return sum;
205}
206#define csum_tcpudp_nofold csum_tcpudp_nofold
207
208/*
209 * this routine is used for miscellaneous IP-like checksums, mainly
210 * in icmp.c
211 */
212static inline __sum16 ip_compute_csum(const void *buff, int len)
213{
214 return csum_fold(csum_partial(buff, len, 0));
215}
216
217#define _HAVE_ARCH_IPV6_CSUM
218static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
219 const struct in6_addr *daddr,
220 __u32 len, __u8 proto,
221 __wsum sum)
222{
223 __wsum tmp;
224
225 __asm__(
226 " .set push # csum_ipv6_magic\n"
227 " .set noreorder \n"
228 " .set noat \n"
229 " addu %0, %5 # proto (long in network byte order)\n"
230 " sltu $1, %0, %5 \n"
231 " addu %0, $1 \n"
232
233 " addu %0, %6 # csum\n"
234 " sltu $1, %0, %6 \n"
235 " lw %1, 0(%2) # four words source address\n"
236 " addu %0, $1 \n"
237 " addu %0, %1 \n"
238 " sltu $1, %0, %1 \n"
239
240 " lw %1, 4(%2) \n"
241 " addu %0, $1 \n"
242 " addu %0, %1 \n"
243 " sltu $1, %0, %1 \n"
244
245 " lw %1, 8(%2) \n"
246 " addu %0, $1 \n"
247 " addu %0, %1 \n"
248 " sltu $1, %0, %1 \n"
249
250 " lw %1, 12(%2) \n"
251 " addu %0, $1 \n"
252 " addu %0, %1 \n"
253 " sltu $1, %0, %1 \n"
254
255 " lw %1, 0(%3) \n"
256 " addu %0, $1 \n"
257 " addu %0, %1 \n"
258 " sltu $1, %0, %1 \n"
259
260 " lw %1, 4(%3) \n"
261 " addu %0, $1 \n"
262 " addu %0, %1 \n"
263 " sltu $1, %0, %1 \n"
264
265 " lw %1, 8(%3) \n"
266 " addu %0, $1 \n"
267 " addu %0, %1 \n"
268 " sltu $1, %0, %1 \n"
269
270 " lw %1, 12(%3) \n"
271 " addu %0, $1 \n"
272 " addu %0, %1 \n"
273 " sltu $1, %0, %1 \n"
274
275 " addu %0, $1 # Add final carry\n"
276 " .set pop"
277 : "=&r" (sum), "=&r" (tmp)
278 : "r" (saddr), "r" (daddr),
279 "0" (htonl(len)), "r" (htonl(proto)), "r" (sum));
280
281 return csum_fold(sum);
282}
283
284#include <asm-generic/checksum.h>
285#endif /* CONFIG_GENERIC_CSUM */
286
287#endif /* _ASM_CHECKSUM_H */