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 */
48 static inline
csum_partial_copy_from_user(const void __user * src,void * dst,int len,__wsum sum,int * err_ptr)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
62 static inline
csum_and_copy_from_user(const void __user * src,void * dst,int len,__wsum sum,int * err_ptr)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
79 static inline
csum_and_copy_to_user(const void * src,void __user * dst,int len,__wsum sum,int * err_ptr)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 */
csum_fold(__wsum csum)111 static 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 */
ip_fast_csum(const void * iph,unsigned int ihl)131 static 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
csum_tcpudp_nofold(__be32 saddr,__be32 daddr,unsigned short len,unsigned short proto,__wsum sum)163 static 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 */
ip_compute_csum(const void * buff,int len)210 static 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
csum_ipv6_magic(const struct in6_addr * saddr,const struct in6_addr * daddr,__u32 len,unsigned short proto,__wsum sum)216 static __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