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
csum_and_copy_from_user(const void __user * src,void * dst,int len)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
csum_and_copy_to_user(const void * src,void __user * dst,int len)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);
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 */
csum_fold(__wsum csum)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 */
ip_fast_csum(const void * iph,unsigned int ihl)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
csum_tcpudp_nofold(__be32 saddr,__be32 daddr,__u32 len,__u8 proto,__wsum isum)129 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
130 __u32 len, __u8 proto,
131 __wsum isum)
132 {
133 const unsigned int sh32 = IS_ENABLED(CONFIG_64BIT) ? 32 : 0;
134 unsigned long sum = (__force unsigned long)daddr;
135 unsigned long tmp;
136 __u32 osum;
137
138 tmp = (__force unsigned long)saddr;
139 sum += tmp;
140
141 if (IS_ENABLED(CONFIG_32BIT))
142 sum += sum < tmp;
143
144 /*
145 * We know PROTO + LEN has the sign bit clear, so cast to a signed
146 * type to avoid an extraneous zero-extension where TMP is 64-bit.
147 */
148 tmp = (__s32)(proto + len);
149 tmp <<= IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? 8 : 0;
150 sum += tmp;
151 if (IS_ENABLED(CONFIG_32BIT))
152 sum += sum < tmp;
153
154 tmp = (__force unsigned long)isum;
155 sum += tmp;
156
157 if (IS_ENABLED(CONFIG_32BIT)) {
158 sum += sum < tmp;
159 osum = sum;
160 } else if (IS_ENABLED(CONFIG_64BIT)) {
161 tmp = sum << sh32;
162 sum += tmp;
163 osum = sum < tmp;
164 osum += sum >> sh32;
165 } else {
166 BUILD_BUG();
167 }
168
169 return (__force __wsum)osum;
170 }
171 #define csum_tcpudp_nofold csum_tcpudp_nofold
172
173 /*
174 * this routine is used for miscellaneous IP-like checksums, mainly
175 * in icmp.c
176 */
ip_compute_csum(const void * buff,int len)177 static inline __sum16 ip_compute_csum(const void *buff, int len)
178 {
179 return csum_fold(csum_partial(buff, len, 0));
180 }
181
182 #define _HAVE_ARCH_IPV6_CSUM
csum_ipv6_magic(const struct in6_addr * saddr,const struct in6_addr * daddr,__u32 len,__u8 proto,__wsum sum)183 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
184 const struct in6_addr *daddr,
185 __u32 len, __u8 proto,
186 __wsum sum)
187 {
188 __wsum tmp;
189
190 __asm__(
191 " .set push # csum_ipv6_magic\n"
192 " .set noreorder \n"
193 " .set noat \n"
194 " addu %0, %5 # proto (long in network byte order)\n"
195 " sltu $1, %0, %5 \n"
196 " addu %0, $1 \n"
197
198 " addu %0, %6 # csum\n"
199 " sltu $1, %0, %6 \n"
200 " lw %1, 0(%2) # four words source address\n"
201 " addu %0, $1 \n"
202 " addu %0, %1 \n"
203 " sltu $1, %0, %1 \n"
204
205 " lw %1, 4(%2) \n"
206 " addu %0, $1 \n"
207 " addu %0, %1 \n"
208 " sltu $1, %0, %1 \n"
209
210 " lw %1, 8(%2) \n"
211 " addu %0, $1 \n"
212 " addu %0, %1 \n"
213 " sltu $1, %0, %1 \n"
214
215 " lw %1, 12(%2) \n"
216 " addu %0, $1 \n"
217 " addu %0, %1 \n"
218 " sltu $1, %0, %1 \n"
219
220 " lw %1, 0(%3) \n"
221 " addu %0, $1 \n"
222 " addu %0, %1 \n"
223 " sltu $1, %0, %1 \n"
224
225 " lw %1, 4(%3) \n"
226 " addu %0, $1 \n"
227 " addu %0, %1 \n"
228 " sltu $1, %0, %1 \n"
229
230 " lw %1, 8(%3) \n"
231 " addu %0, $1 \n"
232 " addu %0, %1 \n"
233 " sltu $1, %0, %1 \n"
234
235 " lw %1, 12(%3) \n"
236 " addu %0, $1 \n"
237 " addu %0, %1 \n"
238 " sltu $1, %0, %1 \n"
239
240 " addu %0, $1 # Add final carry\n"
241 " .set pop"
242 : "=&r" (sum), "=&r" (tmp)
243 : "r" (saddr), "r" (daddr),
244 "0" (htonl(len)), "r" (htonl(proto)), "r" (sum)
245 : "memory");
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