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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 | */ | |
23 | unsigned int csum_partial(const unsigned char * buff, int len, | |
24 | unsigned int sum); | |
25 | ||
1da177e4 LT |
26 | /* |
27 | * Note: when you get a NULL pointer exception here this means someone | |
28 | * passed in an incorrect kernel address to one of these functions. | |
29 | * | |
30 | * If you use these functions directly please don't forget the | |
31 | * access_ok(). | |
32 | */ | |
33 | ||
34 | static __inline__ | |
35 | unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst, | |
36 | int len, int sum) | |
37 | { | |
38 | memcpy(dst, src, len); | |
014c2544 | 39 | return csum_partial(dst, len, sum); |
1da177e4 LT |
40 | } |
41 | ||
7d37c6d5 BS |
42 | /* |
43 | * the same as csum_partial, but copies from src while it | |
44 | * checksums, and handles user-space pointer exceptions correctly, when needed. | |
45 | * | |
46 | * here even more important to align src and dst on a 32-bit (or even | |
47 | * better 64-bit) boundary | |
48 | */ | |
49 | ||
1da177e4 LT |
50 | static __inline__ |
51 | unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst, | |
52 | int len, int sum, int *err_ptr) | |
53 | { | |
7d37c6d5 BS |
54 | if(copy_from_user(dst, src, len)){ |
55 | *err_ptr = -EFAULT; | |
56 | return(-1); | |
57 | } | |
58 | ||
59 | return csum_partial(dst, len, sum); | |
1da177e4 LT |
60 | } |
61 | ||
62 | /* | |
63 | * These are the old (and unsafe) way of doing checksums, a warning message | |
64 | * will be printed if they are used and an exception occurs. | |
65 | * | |
66 | * these functions should go away after some time. | |
67 | */ | |
68 | ||
69 | #define csum_partial_copy_fromuser csum_partial_copy_from_user | |
1da177e4 LT |
70 | |
71 | /* | |
72 | * This is a version of ip_compute_csum() optimized for IP headers, | |
73 | * which always checksum on 4 octet boundaries. | |
74 | * | |
75 | * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by | |
76 | * Arnt Gulbrandsen. | |
77 | */ | |
78 | static inline unsigned short ip_fast_csum(unsigned char * iph, | |
79 | unsigned int ihl) | |
80 | { | |
81 | unsigned int sum; | |
82 | ||
83 | __asm__ __volatile__( | |
84 | "movl (%1), %0 ;\n" | |
85 | "subl $4, %2 ;\n" | |
86 | "jbe 2f ;\n" | |
87 | "addl 4(%1), %0 ;\n" | |
88 | "adcl 8(%1), %0 ;\n" | |
89 | "adcl 12(%1), %0 ;\n" | |
90 | "1: adcl 16(%1), %0 ;\n" | |
91 | "lea 4(%1), %1 ;\n" | |
92 | "decl %2 ;\n" | |
93 | "jne 1b ;\n" | |
94 | "adcl $0, %0 ;\n" | |
95 | "movl %0, %2 ;\n" | |
96 | "shrl $16, %0 ;\n" | |
97 | "addw %w2, %w0 ;\n" | |
98 | "adcl $0, %0 ;\n" | |
99 | "notl %0 ;\n" | |
100 | "2: ;\n" | |
101 | /* Since the input registers which are loaded with iph and ipl | |
102 | are modified, we must also specify them as outputs, or gcc | |
103 | will assume they contain their original values. */ | |
104 | : "=r" (sum), "=r" (iph), "=r" (ihl) | |
105 | : "1" (iph), "2" (ihl) | |
106 | : "memory"); | |
014c2544 | 107 | return sum; |
1da177e4 LT |
108 | } |
109 | ||
110 | /* | |
111 | * Fold a partial checksum | |
112 | */ | |
113 | ||
114 | static inline unsigned int csum_fold(unsigned int sum) | |
115 | { | |
116 | __asm__( | |
117 | "addl %1, %0 ;\n" | |
118 | "adcl $0xffff, %0 ;\n" | |
119 | : "=r" (sum) | |
120 | : "r" (sum << 16), "0" (sum & 0xffff0000) | |
121 | ); | |
122 | return (~sum) >> 16; | |
123 | } | |
124 | ||
125 | static inline unsigned long csum_tcpudp_nofold(unsigned long saddr, | |
126 | unsigned long daddr, | |
127 | unsigned short len, | |
128 | unsigned short proto, | |
129 | unsigned int sum) | |
130 | { | |
131 | __asm__( | |
132 | "addl %1, %0 ;\n" | |
133 | "adcl %2, %0 ;\n" | |
134 | "adcl %3, %0 ;\n" | |
135 | "adcl $0, %0 ;\n" | |
136 | : "=r" (sum) | |
137 | : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum)); | |
138 | return sum; | |
139 | } | |
140 | ||
141 | /* | |
142 | * computes the checksum of the TCP/UDP pseudo-header | |
143 | * returns a 16-bit checksum, already complemented | |
144 | */ | |
145 | static inline unsigned short int csum_tcpudp_magic(unsigned long saddr, | |
146 | unsigned long daddr, | |
147 | unsigned short len, | |
148 | unsigned short proto, | |
149 | unsigned int sum) | |
150 | { | |
151 | return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); | |
152 | } | |
153 | ||
154 | /* | |
155 | * this routine is used for miscellaneous IP-like checksums, mainly | |
156 | * in icmp.c | |
157 | */ | |
158 | ||
159 | static inline unsigned short ip_compute_csum(unsigned char * buff, int len) | |
160 | { | |
161 | return csum_fold (csum_partial(buff, len, 0)); | |
162 | } | |
163 | ||
164 | #define _HAVE_ARCH_IPV6_CSUM | |
165 | static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr, | |
166 | struct in6_addr *daddr, | |
167 | __u32 len, | |
168 | unsigned short proto, | |
169 | unsigned int sum) | |
170 | { | |
171 | __asm__( | |
172 | "addl 0(%1), %0 ;\n" | |
173 | "adcl 4(%1), %0 ;\n" | |
174 | "adcl 8(%1), %0 ;\n" | |
175 | "adcl 12(%1), %0 ;\n" | |
176 | "adcl 0(%2), %0 ;\n" | |
177 | "adcl 4(%2), %0 ;\n" | |
178 | "adcl 8(%2), %0 ;\n" | |
179 | "adcl 12(%2), %0 ;\n" | |
180 | "adcl %3, %0 ;\n" | |
181 | "adcl %4, %0 ;\n" | |
182 | "adcl $0, %0 ;\n" | |
183 | : "=&r" (sum) | |
184 | : "r" (saddr), "r" (daddr), | |
185 | "r"(htonl(len)), "r"(htonl(proto)), "0"(sum)); | |
186 | ||
187 | return csum_fold(sum); | |
188 | } | |
189 | ||
190 | /* | |
191 | * Copy and checksum to user | |
192 | */ | |
193 | #define HAVE_CSUM_COPY_USER | |
194 | static __inline__ unsigned int csum_and_copy_to_user(const unsigned char *src, | |
195 | unsigned char *dst, | |
196 | int len, int sum, int *err_ptr) | |
197 | { | |
7d37c6d5 BS |
198 | if (access_ok(VERIFY_WRITE, dst, len)){ |
199 | if(copy_to_user(dst, src, len)){ | |
200 | *err_ptr = -EFAULT; | |
201 | return(-1); | |
202 | } | |
203 | ||
204 | return csum_partial(src, len, sum); | |
205 | } | |
1da177e4 LT |
206 | |
207 | if (len) | |
208 | *err_ptr = -EFAULT; | |
209 | ||
210 | return -1; /* invalid checksum */ | |
211 | } | |
212 | ||
213 | #endif | |
214 | ||
215 | /* | |
216 | * Overrides for Emacs so that we follow Linus's tabbing style. | |
217 | * Emacs will notice this stuff at the end of the file and automatically | |
218 | * adjust the settings for this buffer only. This must remain at the end | |
219 | * of the file. | |
220 | * --------------------------------------------------------------------------- | |
221 | * Local variables: | |
222 | * c-file-style: "linux" | |
223 | * End: | |
224 | */ |