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1da177e4 LT |
1 | #ifndef _I386_CHECKSUM_H |
2 | #define _I386_CHECKSUM_H | |
3 | ||
4 | #include <linux/in6.h> | |
5 | ||
6 | /* | |
7 | * computes the checksum of a memory block at buff, length len, | |
8 | * and adds in "sum" (32-bit) | |
9 | * | |
10 | * returns a 32-bit number suitable for feeding into itself | |
11 | * or csum_tcpudp_magic | |
12 | * | |
13 | * this function must be called with even lengths, except | |
14 | * for the last fragment, which may be odd | |
15 | * | |
16 | * it's best to have buff aligned on a 32-bit boundary | |
17 | */ | |
18 | asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum); | |
19 | ||
20 | /* | |
21 | * the same as csum_partial, but copies from src while it | |
22 | * checksums, and handles user-space pointer exceptions correctly, when needed. | |
23 | * | |
24 | * here even more important to align src and dst on a 32-bit (or even | |
25 | * better 64-bit) boundary | |
26 | */ | |
27 | ||
28 | asmlinkage unsigned int csum_partial_copy_generic(const unsigned char *src, unsigned char *dst, | |
29 | int len, int sum, int *src_err_ptr, int *dst_err_ptr); | |
30 | ||
31 | /* | |
32 | * Note: when you get a NULL pointer exception here this means someone | |
33 | * passed in an incorrect kernel address to one of these functions. | |
34 | * | |
35 | * If you use these functions directly please don't forget the | |
36 | * verify_area(). | |
37 | */ | |
38 | static __inline__ | |
39 | unsigned int csum_partial_copy_nocheck (const unsigned char *src, unsigned char *dst, | |
40 | int len, int sum) | |
41 | { | |
42 | return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL); | |
43 | } | |
44 | ||
45 | static __inline__ | |
46 | unsigned int csum_partial_copy_from_user(const unsigned char __user *src, unsigned char *dst, | |
47 | int len, int sum, int *err_ptr) | |
48 | { | |
49 | might_sleep(); | |
50 | return csum_partial_copy_generic((__force unsigned char *)src, dst, | |
51 | len, sum, err_ptr, NULL); | |
52 | } | |
53 | ||
54 | /* | |
55 | * This is a version of ip_compute_csum() optimized for IP headers, | |
56 | * which always checksum on 4 octet boundaries. | |
57 | * | |
58 | * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by | |
59 | * Arnt Gulbrandsen. | |
60 | */ | |
61 | static inline unsigned short ip_fast_csum(unsigned char * iph, | |
62 | unsigned int ihl) | |
63 | { | |
64 | unsigned int sum; | |
65 | ||
66 | __asm__ __volatile__( | |
67 | "movl (%1), %0 ;\n" | |
68 | "subl $4, %2 ;\n" | |
69 | "jbe 2f ;\n" | |
70 | "addl 4(%1), %0 ;\n" | |
71 | "adcl 8(%1), %0 ;\n" | |
72 | "adcl 12(%1), %0 ;\n" | |
73 | "1: adcl 16(%1), %0 ;\n" | |
74 | "lea 4(%1), %1 ;\n" | |
75 | "decl %2 ;\n" | |
76 | "jne 1b ;\n" | |
77 | "adcl $0, %0 ;\n" | |
78 | "movl %0, %2 ;\n" | |
79 | "shrl $16, %0 ;\n" | |
80 | "addw %w2, %w0 ;\n" | |
81 | "adcl $0, %0 ;\n" | |
82 | "notl %0 ;\n" | |
83 | "2: ;\n" | |
84 | /* Since the input registers which are loaded with iph and ipl | |
85 | are modified, we must also specify them as outputs, or gcc | |
86 | will assume they contain their original values. */ | |
87 | : "=r" (sum), "=r" (iph), "=r" (ihl) | |
88 | : "1" (iph), "2" (ihl) | |
89 | : "memory"); | |
90 | return(sum); | |
91 | } | |
92 | ||
93 | /* | |
94 | * Fold a partial checksum | |
95 | */ | |
96 | ||
97 | static inline unsigned int csum_fold(unsigned int sum) | |
98 | { | |
99 | __asm__( | |
100 | "addl %1, %0 ;\n" | |
101 | "adcl $0xffff, %0 ;\n" | |
102 | : "=r" (sum) | |
103 | : "r" (sum << 16), "0" (sum & 0xffff0000) | |
104 | ); | |
105 | return (~sum) >> 16; | |
106 | } | |
107 | ||
108 | static inline unsigned long csum_tcpudp_nofold(unsigned long saddr, | |
109 | unsigned long daddr, | |
110 | unsigned short len, | |
111 | unsigned short proto, | |
112 | unsigned int sum) | |
113 | { | |
114 | __asm__( | |
115 | "addl %1, %0 ;\n" | |
116 | "adcl %2, %0 ;\n" | |
117 | "adcl %3, %0 ;\n" | |
118 | "adcl $0, %0 ;\n" | |
119 | : "=r" (sum) | |
120 | : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum)); | |
121 | return sum; | |
122 | } | |
123 | ||
124 | /* | |
125 | * computes the checksum of the TCP/UDP pseudo-header | |
126 | * returns a 16-bit checksum, already complemented | |
127 | */ | |
128 | static inline unsigned short int csum_tcpudp_magic(unsigned long saddr, | |
129 | unsigned long daddr, | |
130 | unsigned short len, | |
131 | unsigned short proto, | |
132 | unsigned int sum) | |
133 | { | |
134 | return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); | |
135 | } | |
136 | ||
137 | /* | |
138 | * this routine is used for miscellaneous IP-like checksums, mainly | |
139 | * in icmp.c | |
140 | */ | |
141 | ||
142 | static inline unsigned short ip_compute_csum(unsigned char * buff, int len) | |
143 | { | |
144 | return csum_fold (csum_partial(buff, len, 0)); | |
145 | } | |
146 | ||
147 | #define _HAVE_ARCH_IPV6_CSUM | |
148 | static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr, | |
149 | struct in6_addr *daddr, | |
150 | __u32 len, | |
151 | unsigned short proto, | |
152 | unsigned int sum) | |
153 | { | |
154 | __asm__( | |
155 | "addl 0(%1), %0 ;\n" | |
156 | "adcl 4(%1), %0 ;\n" | |
157 | "adcl 8(%1), %0 ;\n" | |
158 | "adcl 12(%1), %0 ;\n" | |
159 | "adcl 0(%2), %0 ;\n" | |
160 | "adcl 4(%2), %0 ;\n" | |
161 | "adcl 8(%2), %0 ;\n" | |
162 | "adcl 12(%2), %0 ;\n" | |
163 | "adcl %3, %0 ;\n" | |
164 | "adcl %4, %0 ;\n" | |
165 | "adcl $0, %0 ;\n" | |
166 | : "=&r" (sum) | |
167 | : "r" (saddr), "r" (daddr), | |
168 | "r"(htonl(len)), "r"(htonl(proto)), "0"(sum)); | |
169 | ||
170 | return csum_fold(sum); | |
171 | } | |
172 | ||
173 | /* | |
174 | * Copy and checksum to user | |
175 | */ | |
176 | #define HAVE_CSUM_COPY_USER | |
177 | static __inline__ unsigned int csum_and_copy_to_user(const unsigned char *src, | |
178 | unsigned char __user *dst, | |
179 | int len, int sum, | |
180 | int *err_ptr) | |
181 | { | |
182 | might_sleep(); | |
183 | if (access_ok(VERIFY_WRITE, dst, len)) | |
184 | return csum_partial_copy_generic(src, (__force unsigned char *)dst, len, sum, NULL, err_ptr); | |
185 | ||
186 | if (len) | |
187 | *err_ptr = -EFAULT; | |
188 | ||
189 | return -1; /* invalid checksum */ | |
190 | } | |
191 | ||
192 | #endif |