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1da177e4 LT |
1 | /* |
2 | * Licensed under the GPL | |
3 | */ | |
4 | ||
5 | #ifndef __UM_SYSDEP_CHECKSUM_H | |
6 | #define __UM_SYSDEP_CHECKSUM_H | |
7 | ||
8 | #include "linux/in6.h" | |
9 | #include "linux/string.h" | |
10 | ||
11 | /* | |
12 | * computes the checksum of a memory block at buff, length len, | |
13 | * and adds in "sum" (32-bit) | |
14 | * | |
15 | * returns a 32-bit number suitable for feeding into itself | |
16 | * or csum_tcpudp_magic | |
17 | * | |
18 | * this function must be called with even lengths, except | |
19 | * for the last fragment, which may be odd | |
20 | * | |
21 | * it's best to have buff aligned on a 32-bit boundary | |
22 | */ | |
abf419b8 | 23 | __wsum csum_partial(const void *buff, int len, __wsum sum); |
1da177e4 | 24 | |
1da177e4 LT |
25 | /* |
26 | * Note: when you get a NULL pointer exception here this means someone | |
27 | * passed in an incorrect kernel address to one of these functions. | |
28 | * | |
29 | * If you use these functions directly please don't forget the | |
30 | * access_ok(). | |
31 | */ | |
32 | ||
33 | static __inline__ | |
abf419b8 AV |
34 | __wsum csum_partial_copy_nocheck(const void *src, void *dst, |
35 | int len, __wsum sum) | |
1da177e4 LT |
36 | { |
37 | memcpy(dst, src, len); | |
014c2544 | 38 | return csum_partial(dst, len, sum); |
1da177e4 LT |
39 | } |
40 | ||
7d37c6d5 BS |
41 | /* |
42 | * the same as csum_partial, but copies from src while it | |
43 | * checksums, and handles user-space pointer exceptions correctly, when needed. | |
44 | * | |
45 | * here even more important to align src and dst on a 32-bit (or even | |
46 | * better 64-bit) boundary | |
47 | */ | |
48 | ||
1da177e4 | 49 | static __inline__ |
abf419b8 AV |
50 | __wsum csum_partial_copy_from_user(const void __user *src, void *dst, |
51 | int len, __wsum sum, int *err_ptr) | |
1da177e4 | 52 | { |
abf419b8 | 53 | if (copy_from_user(dst, src, len)) { |
7d37c6d5 | 54 | *err_ptr = -EFAULT; |
abf419b8 | 55 | return (__force __wsum)-1; |
7d37c6d5 BS |
56 | } |
57 | ||
58 | return csum_partial(dst, len, sum); | |
1da177e4 LT |
59 | } |
60 | ||
1da177e4 LT |
61 | /* |
62 | * This is a version of ip_compute_csum() optimized for IP headers, | |
63 | * which always checksum on 4 octet boundaries. | |
64 | * | |
65 | * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by | |
66 | * Arnt Gulbrandsen. | |
67 | */ | |
abf419b8 | 68 | static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) |
1da177e4 LT |
69 | { |
70 | unsigned int sum; | |
71 | ||
72 | __asm__ __volatile__( | |
73 | "movl (%1), %0 ;\n" | |
74 | "subl $4, %2 ;\n" | |
75 | "jbe 2f ;\n" | |
76 | "addl 4(%1), %0 ;\n" | |
77 | "adcl 8(%1), %0 ;\n" | |
78 | "adcl 12(%1), %0 ;\n" | |
79 | "1: adcl 16(%1), %0 ;\n" | |
80 | "lea 4(%1), %1 ;\n" | |
81 | "decl %2 ;\n" | |
82 | "jne 1b ;\n" | |
83 | "adcl $0, %0 ;\n" | |
84 | "movl %0, %2 ;\n" | |
85 | "shrl $16, %0 ;\n" | |
86 | "addw %w2, %w0 ;\n" | |
87 | "adcl $0, %0 ;\n" | |
88 | "notl %0 ;\n" | |
89 | "2: ;\n" | |
90 | /* Since the input registers which are loaded with iph and ipl | |
91 | are modified, we must also specify them as outputs, or gcc | |
92 | will assume they contain their original values. */ | |
93 | : "=r" (sum), "=r" (iph), "=r" (ihl) | |
94 | : "1" (iph), "2" (ihl) | |
95 | : "memory"); | |
abf419b8 | 96 | return (__force __sum16)sum; |
1da177e4 LT |
97 | } |
98 | ||
99 | /* | |
100 | * Fold a partial checksum | |
101 | */ | |
102 | ||
abf419b8 | 103 | static inline __sum16 csum_fold(__wsum sum) |
1da177e4 LT |
104 | { |
105 | __asm__( | |
106 | "addl %1, %0 ;\n" | |
107 | "adcl $0xffff, %0 ;\n" | |
108 | : "=r" (sum) | |
abf419b8 AV |
109 | : "r" ((__force u32)sum << 16), |
110 | "0" ((__force u32)sum & 0xffff0000) | |
1da177e4 | 111 | ); |
abf419b8 | 112 | return (__force __sum16)(~(__force u32)sum >> 16); |
1da177e4 LT |
113 | } |
114 | ||
abf419b8 | 115 | static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, |
1da177e4 LT |
116 | unsigned short len, |
117 | unsigned short proto, | |
abf419b8 | 118 | __wsum sum) |
1da177e4 LT |
119 | { |
120 | __asm__( | |
121 | "addl %1, %0 ;\n" | |
122 | "adcl %2, %0 ;\n" | |
123 | "adcl %3, %0 ;\n" | |
124 | "adcl $0, %0 ;\n" | |
125 | : "=r" (sum) | |
abf419b8 | 126 | : "g" (daddr), "g"(saddr), "g"((len + proto) << 8), "0"(sum)); |
1da177e4 LT |
127 | return sum; |
128 | } | |
129 | ||
130 | /* | |
131 | * computes the checksum of the TCP/UDP pseudo-header | |
132 | * returns a 16-bit checksum, already complemented | |
133 | */ | |
abf419b8 | 134 | static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, |
1da177e4 LT |
135 | unsigned short len, |
136 | unsigned short proto, | |
abf419b8 | 137 | __wsum sum) |
1da177e4 LT |
138 | { |
139 | return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); | |
140 | } | |
141 | ||
142 | /* | |
143 | * this routine is used for miscellaneous IP-like checksums, mainly | |
144 | * in icmp.c | |
145 | */ | |
146 | ||
abf419b8 | 147 | static inline __sum16 ip_compute_csum(const void *buff, int len) |
1da177e4 LT |
148 | { |
149 | return csum_fold (csum_partial(buff, len, 0)); | |
150 | } | |
151 | ||
152 | #define _HAVE_ARCH_IPV6_CSUM | |
abf419b8 AV |
153 | static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr, |
154 | const struct in6_addr *daddr, | |
155 | __u32 len, unsigned short proto, | |
156 | __wsum sum) | |
1da177e4 LT |
157 | { |
158 | __asm__( | |
159 | "addl 0(%1), %0 ;\n" | |
160 | "adcl 4(%1), %0 ;\n" | |
161 | "adcl 8(%1), %0 ;\n" | |
162 | "adcl 12(%1), %0 ;\n" | |
163 | "adcl 0(%2), %0 ;\n" | |
164 | "adcl 4(%2), %0 ;\n" | |
165 | "adcl 8(%2), %0 ;\n" | |
166 | "adcl 12(%2), %0 ;\n" | |
167 | "adcl %3, %0 ;\n" | |
168 | "adcl %4, %0 ;\n" | |
169 | "adcl $0, %0 ;\n" | |
170 | : "=&r" (sum) | |
171 | : "r" (saddr), "r" (daddr), | |
172 | "r"(htonl(len)), "r"(htonl(proto)), "0"(sum)); | |
173 | ||
174 | return csum_fold(sum); | |
175 | } | |
176 | ||
177 | /* | |
178 | * Copy and checksum to user | |
179 | */ | |
180 | #define HAVE_CSUM_COPY_USER | |
abf419b8 AV |
181 | static __inline__ __wsum csum_and_copy_to_user(const void *src, |
182 | void __user *dst, | |
183 | int len, __wsum sum, int *err_ptr) | |
1da177e4 | 184 | { |
abf419b8 AV |
185 | if (access_ok(VERIFY_WRITE, dst, len)) { |
186 | if (copy_to_user(dst, src, len)) { | |
7d37c6d5 | 187 | *err_ptr = -EFAULT; |
abf419b8 | 188 | return (__force __wsum)-1; |
7d37c6d5 BS |
189 | } |
190 | ||
191 | return csum_partial(src, len, sum); | |
192 | } | |
1da177e4 LT |
193 | |
194 | if (len) | |
195 | *err_ptr = -EFAULT; | |
196 | ||
abf419b8 | 197 | return (__force __wsum)-1; /* invalid checksum */ |
1da177e4 LT |
198 | } |
199 | ||
200 | #endif | |
201 | ||
202 | /* | |
203 | * Overrides for Emacs so that we follow Linus's tabbing style. | |
204 | * Emacs will notice this stuff at the end of the file and automatically | |
205 | * adjust the settings for this buffer only. This must remain at the end | |
206 | * of the file. | |
207 | * --------------------------------------------------------------------------- | |
208 | * Local variables: | |
209 | * c-file-style: "linux" | |
210 | * End: | |
211 | */ |