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1da177e4 LT |
1 | #ifndef _I386_CHECKSUM_H |
2 | #define _I386_CHECKSUM_H | |
3 | ||
4 | #include <linux/in6.h> | |
5 | ||
a9ed8817 AD |
6 | #include <asm/uaccess.h> |
7 | ||
1da177e4 LT |
8 | /* |
9 | * computes the checksum of a memory block at buff, length len, | |
10 | * and adds in "sum" (32-bit) | |
11 | * | |
12 | * returns a 32-bit number suitable for feeding into itself | |
13 | * or csum_tcpudp_magic | |
14 | * | |
15 | * this function must be called with even lengths, except | |
16 | * for the last fragment, which may be odd | |
17 | * | |
18 | * it's best to have buff aligned on a 32-bit boundary | |
19 | */ | |
72685fcd | 20 | asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum); |
1da177e4 LT |
21 | |
22 | /* | |
23 | * the same as csum_partial, but copies from src while it | |
24 | * checksums, and handles user-space pointer exceptions correctly, when needed. | |
25 | * | |
26 | * here even more important to align src and dst on a 32-bit (or even | |
27 | * better 64-bit) boundary | |
28 | */ | |
29 | ||
72685fcd | 30 | asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, |
0883e91a JP |
31 | int len, __wsum sum, |
32 | int *src_err_ptr, int *dst_err_ptr); | |
1da177e4 LT |
33 | |
34 | /* | |
35 | * Note: when you get a NULL pointer exception here this means someone | |
36 | * passed in an incorrect kernel address to one of these functions. | |
37 | * | |
38 | * If you use these functions directly please don't forget the | |
e49332bd | 39 | * access_ok(). |
1da177e4 | 40 | */ |
0883e91a JP |
41 | static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, |
42 | int len, __wsum sum) | |
1da177e4 | 43 | { |
0883e91a | 44 | return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL); |
1da177e4 LT |
45 | } |
46 | ||
0883e91a JP |
47 | static inline __wsum csum_partial_copy_from_user(const void __user *src, |
48 | void *dst, | |
49 | int len, __wsum sum, | |
50 | int *err_ptr) | |
1da177e4 LT |
51 | { |
52 | might_sleep(); | |
72685fcd | 53 | return csum_partial_copy_generic((__force void *)src, dst, |
0883e91a | 54 | len, sum, err_ptr, NULL); |
1da177e4 LT |
55 | } |
56 | ||
57 | /* | |
58 | * This is a version of ip_compute_csum() optimized for IP headers, | |
59 | * which always checksum on 4 octet boundaries. | |
60 | * | |
61 | * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by | |
62 | * Arnt Gulbrandsen. | |
63 | */ | |
72685fcd | 64 | static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) |
1da177e4 LT |
65 | { |
66 | unsigned int sum; | |
67 | ||
0883e91a JP |
68 | asm volatile("movl (%1), %0 ;\n" |
69 | "subl $4, %2 ;\n" | |
70 | "jbe 2f ;\n" | |
71 | "addl 4(%1), %0 ;\n" | |
72 | "adcl 8(%1), %0 ;\n" | |
73 | "adcl 12(%1), %0;\n" | |
74 | "1: adcl 16(%1), %0 ;\n" | |
75 | "lea 4(%1), %1 ;\n" | |
76 | "decl %2 ;\n" | |
77 | "jne 1b ;\n" | |
78 | "adcl $0, %0 ;\n" | |
79 | "movl %0, %2 ;\n" | |
80 | "shrl $16, %0 ;\n" | |
81 | "addw %w2, %w0 ;\n" | |
82 | "adcl $0, %0 ;\n" | |
83 | "notl %0 ;\n" | |
84 | "2: ;\n" | |
2c656491 | 85 | /* Since the input registers which are loaded with iph and ihl |
1da177e4 LT |
86 | are modified, we must also specify them as outputs, or gcc |
87 | will assume they contain their original values. */ | |
0883e91a JP |
88 | : "=r" (sum), "=r" (iph), "=r" (ihl) |
89 | : "1" (iph), "2" (ihl) | |
90 | : "memory"); | |
72685fcd | 91 | return (__force __sum16)sum; |
1da177e4 LT |
92 | } |
93 | ||
94 | /* | |
95 | * Fold a partial checksum | |
96 | */ | |
97 | ||
72685fcd | 98 | static inline __sum16 csum_fold(__wsum sum) |
1da177e4 | 99 | { |
0883e91a JP |
100 | asm("addl %1, %0 ;\n" |
101 | "adcl $0xffff, %0 ;\n" | |
102 | : "=r" (sum) | |
103 | : "r" ((__force u32)sum << 16), | |
104 | "0" ((__force u32)sum & 0xffff0000)); | |
72685fcd | 105 | return (__force __sum16)(~(__force u32)sum >> 16); |
1da177e4 LT |
106 | } |
107 | ||
72685fcd | 108 | static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, |
0883e91a JP |
109 | unsigned short len, |
110 | unsigned short proto, | |
111 | __wsum sum) | |
1da177e4 | 112 | { |
0883e91a JP |
113 | asm("addl %1, %0 ;\n" |
114 | "adcl %2, %0 ;\n" | |
115 | "adcl %3, %0 ;\n" | |
116 | "adcl $0, %0 ;\n" | |
117 | : "=r" (sum) | |
118 | : "g" (daddr), "g"(saddr), | |
119 | "g" ((len + proto) << 8), "0" (sum)); | |
120 | return sum; | |
1da177e4 LT |
121 | } |
122 | ||
123 | /* | |
124 | * computes the checksum of the TCP/UDP pseudo-header | |
125 | * returns a 16-bit checksum, already complemented | |
126 | */ | |
72685fcd | 127 | static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, |
0883e91a JP |
128 | unsigned short len, |
129 | unsigned short proto, | |
130 | __wsum sum) | |
1da177e4 | 131 | { |
0883e91a | 132 | return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); |
1da177e4 LT |
133 | } |
134 | ||
135 | /* | |
136 | * this routine is used for miscellaneous IP-like checksums, mainly | |
137 | * in icmp.c | |
138 | */ | |
139 | ||
72685fcd | 140 | static inline __sum16 ip_compute_csum(const void *buff, int len) |
1da177e4 | 141 | { |
0883e91a | 142 | return csum_fold(csum_partial(buff, len, 0)); |
1da177e4 LT |
143 | } |
144 | ||
145 | #define _HAVE_ARCH_IPV6_CSUM | |
0883e91a JP |
146 | static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr, |
147 | const struct in6_addr *daddr, | |
148 | __u32 len, unsigned short proto, | |
149 | __wsum sum) | |
1da177e4 | 150 | { |
0883e91a JP |
151 | asm("addl 0(%1), %0 ;\n" |
152 | "adcl 4(%1), %0 ;\n" | |
153 | "adcl 8(%1), %0 ;\n" | |
154 | "adcl 12(%1), %0 ;\n" | |
155 | "adcl 0(%2), %0 ;\n" | |
156 | "adcl 4(%2), %0 ;\n" | |
157 | "adcl 8(%2), %0 ;\n" | |
158 | "adcl 12(%2), %0 ;\n" | |
159 | "adcl %3, %0 ;\n" | |
160 | "adcl %4, %0 ;\n" | |
161 | "adcl $0, %0 ;\n" | |
162 | : "=&r" (sum) | |
163 | : "r" (saddr), "r" (daddr), | |
164 | "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)); | |
1da177e4 LT |
165 | |
166 | return csum_fold(sum); | |
167 | } | |
168 | ||
169 | /* | |
170 | * Copy and checksum to user | |
171 | */ | |
172 | #define HAVE_CSUM_COPY_USER | |
0883e91a JP |
173 | static inline __wsum csum_and_copy_to_user(const void *src, |
174 | void __user *dst, | |
175 | int len, __wsum sum, | |
176 | int *err_ptr) | |
1da177e4 LT |
177 | { |
178 | might_sleep(); | |
179 | if (access_ok(VERIFY_WRITE, dst, len)) | |
0883e91a JP |
180 | return csum_partial_copy_generic(src, (__force void *)dst, |
181 | len, sum, NULL, err_ptr); | |
1da177e4 LT |
182 | |
183 | if (len) | |
184 | *err_ptr = -EFAULT; | |
185 | ||
72685fcd | 186 | return (__force __wsum)-1; /* invalid checksum */ |
1da177e4 LT |
187 | } |
188 | ||
189 | #endif |