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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 | */ | |
11 | #ifndef _ASM_CHECKSUM_H | |
12 | #define _ASM_CHECKSUM_H | |
13 | ||
14 | #include <linux/config.h> | |
15 | #include <linux/in6.h> | |
16 | ||
17 | #include <asm/uaccess.h> | |
18 | ||
19 | /* | |
20 | * computes the checksum of a memory block at buff, length len, | |
21 | * and adds in "sum" (32-bit) | |
22 | * | |
23 | * returns a 32-bit number suitable for feeding into itself | |
24 | * or csum_tcpudp_magic | |
25 | * | |
26 | * this function must be called with even lengths, except | |
27 | * for the last fragment, which may be odd | |
28 | * | |
29 | * it's best to have buff aligned on a 32-bit boundary | |
30 | */ | |
31 | unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum); | |
32 | ||
33 | /* | |
34 | * this is a new version of the above that records errors it finds in *errp, | |
35 | * but continues and zeros the rest of the buffer. | |
36 | */ | |
37 | unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst, int len, | |
38 | unsigned int sum, int *errp); | |
39 | ||
40 | /* | |
41 | * Copy and checksum to user | |
42 | */ | |
43 | #define HAVE_CSUM_COPY_USER | |
44 | static inline unsigned int csum_and_copy_to_user (const unsigned char *src, | |
45 | unsigned char __user *dst, | |
46 | int len, int sum, | |
47 | int *err_ptr) | |
48 | { | |
49 | might_sleep(); | |
50 | sum = csum_partial(src, len, sum); | |
51 | ||
52 | if (copy_to_user(dst, src, len)) { | |
53 | *err_ptr = -EFAULT; | |
54 | return -1; | |
55 | } | |
56 | ||
57 | return sum; | |
58 | } | |
59 | ||
60 | /* | |
61 | * the same as csum_partial, but copies from user space (but on MIPS | |
62 | * we have just one address space, so this is identical to the above) | |
63 | */ | |
64 | unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst, | |
65 | int len, unsigned int sum); | |
66 | ||
67 | /* | |
68 | * Fold a partial checksum without adding pseudo headers | |
69 | */ | |
70 | static inline unsigned short int csum_fold(unsigned int sum) | |
71 | { | |
72 | __asm__( | |
73 | ".set\tnoat\t\t\t# csum_fold\n\t" | |
74 | "sll\t$1,%0,16\n\t" | |
75 | "addu\t%0,$1\n\t" | |
76 | "sltu\t$1,%0,$1\n\t" | |
77 | "srl\t%0,%0,16\n\t" | |
78 | "addu\t%0,$1\n\t" | |
79 | "xori\t%0,0xffff\n\t" | |
80 | ".set\tat" | |
81 | : "=r" (sum) | |
82 | : "0" (sum)); | |
83 | ||
84 | return sum; | |
85 | } | |
86 | ||
87 | /* | |
88 | * This is a version of ip_compute_csum() optimized for IP headers, | |
89 | * which always checksum on 4 octet boundaries. | |
90 | * | |
91 | * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by | |
92 | * Arnt Gulbrandsen. | |
93 | */ | |
94 | static inline unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl) | |
95 | { | |
96 | unsigned int *word = (unsigned int *) iph; | |
97 | unsigned int *stop = word + ihl; | |
98 | unsigned int csum; | |
99 | int carry; | |
100 | ||
101 | csum = word[0]; | |
102 | csum += word[1]; | |
103 | carry = (csum < word[1]); | |
104 | csum += carry; | |
105 | ||
106 | csum += word[2]; | |
107 | carry = (csum < word[2]); | |
108 | csum += carry; | |
109 | ||
110 | csum += word[3]; | |
111 | carry = (csum < word[3]); | |
112 | csum += carry; | |
113 | ||
114 | word += 4; | |
115 | do { | |
116 | csum += *word; | |
117 | carry = (csum < *word); | |
118 | csum += carry; | |
119 | word++; | |
120 | } while (word != stop); | |
121 | ||
122 | return csum_fold(csum); | |
123 | } | |
124 | ||
125 | static inline unsigned int csum_tcpudp_nofold(unsigned long saddr, | |
126 | unsigned long daddr, unsigned short len, unsigned short proto, | |
127 | unsigned int sum) | |
128 | { | |
129 | __asm__( | |
130 | ".set\tnoat\t\t\t# csum_tcpudp_nofold\n\t" | |
131 | #ifdef CONFIG_MIPS32 | |
132 | "addu\t%0, %2\n\t" | |
133 | "sltu\t$1, %0, %2\n\t" | |
134 | "addu\t%0, $1\n\t" | |
135 | ||
136 | "addu\t%0, %3\n\t" | |
137 | "sltu\t$1, %0, %3\n\t" | |
138 | "addu\t%0, $1\n\t" | |
139 | ||
140 | "addu\t%0, %4\n\t" | |
141 | "sltu\t$1, %0, %4\n\t" | |
142 | "addu\t%0, $1\n\t" | |
143 | #endif | |
144 | #ifdef CONFIG_MIPS64 | |
145 | "daddu\t%0, %2\n\t" | |
146 | "daddu\t%0, %3\n\t" | |
147 | "daddu\t%0, %4\n\t" | |
148 | "dsll32\t$1, %0, 0\n\t" | |
149 | "daddu\t%0, $1\n\t" | |
150 | "dsrl32\t%0, %0, 0\n\t" | |
151 | #endif | |
152 | ".set\tat" | |
153 | : "=r" (sum) | |
154 | : "0" (daddr), "r"(saddr), | |
155 | #ifdef __MIPSEL__ | |
156 | "r" (((unsigned long)htons(len)<<16) + proto*256), | |
157 | #else | |
158 | "r" (((unsigned long)(proto)<<16) + len), | |
159 | #endif | |
160 | "r" (sum)); | |
161 | ||
162 | return sum; | |
163 | } | |
164 | ||
165 | /* | |
166 | * computes the checksum of the TCP/UDP pseudo-header | |
167 | * returns a 16-bit checksum, already complemented | |
168 | */ | |
169 | static inline unsigned short int csum_tcpudp_magic(unsigned long saddr, | |
170 | unsigned long daddr, | |
171 | unsigned short len, | |
172 | unsigned short proto, | |
173 | unsigned int sum) | |
174 | { | |
175 | return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); | |
176 | } | |
177 | ||
178 | /* | |
179 | * this routine is used for miscellaneous IP-like checksums, mainly | |
180 | * in icmp.c | |
181 | */ | |
182 | static inline unsigned short ip_compute_csum(unsigned char * buff, int len) | |
183 | { | |
184 | return csum_fold(csum_partial(buff, len, 0)); | |
185 | } | |
186 | ||
187 | #define _HAVE_ARCH_IPV6_CSUM | |
188 | static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr, | |
189 | struct in6_addr *daddr, | |
190 | __u32 len, | |
191 | unsigned short proto, | |
192 | unsigned int sum) | |
193 | { | |
194 | __asm__( | |
195 | ".set\tpush\t\t\t# csum_ipv6_magic\n\t" | |
196 | ".set\tnoreorder\n\t" | |
197 | ".set\tnoat\n\t" | |
198 | "addu\t%0, %5\t\t\t# proto (long in network byte order)\n\t" | |
199 | "sltu\t$1, %0, %5\n\t" | |
200 | "addu\t%0, $1\n\t" | |
201 | ||
202 | "addu\t%0, %6\t\t\t# csum\n\t" | |
203 | "sltu\t$1, %0, %6\n\t" | |
204 | "lw\t%1, 0(%2)\t\t\t# four words source address\n\t" | |
205 | "addu\t%0, $1\n\t" | |
206 | "addu\t%0, %1\n\t" | |
207 | "sltu\t$1, %0, %1\n\t" | |
208 | ||
209 | "lw\t%1, 4(%2)\n\t" | |
210 | "addu\t%0, $1\n\t" | |
211 | "addu\t%0, %1\n\t" | |
212 | "sltu\t$1, %0, %1\n\t" | |
213 | ||
214 | "lw\t%1, 8(%2)\n\t" | |
215 | "addu\t%0, $1\n\t" | |
216 | "addu\t%0, %1\n\t" | |
217 | "sltu\t$1, %0, %1\n\t" | |
218 | ||
219 | "lw\t%1, 12(%2)\n\t" | |
220 | "addu\t%0, $1\n\t" | |
221 | "addu\t%0, %1\n\t" | |
222 | "sltu\t$1, %0, %1\n\t" | |
223 | ||
224 | "lw\t%1, 0(%3)\n\t" | |
225 | "addu\t%0, $1\n\t" | |
226 | "addu\t%0, %1\n\t" | |
227 | "sltu\t$1, %0, %1\n\t" | |
228 | ||
229 | "lw\t%1, 4(%3)\n\t" | |
230 | "addu\t%0, $1\n\t" | |
231 | "addu\t%0, %1\n\t" | |
232 | "sltu\t$1, %0, %1\n\t" | |
233 | ||
234 | "lw\t%1, 8(%3)\n\t" | |
235 | "addu\t%0, $1\n\t" | |
236 | "addu\t%0, %1\n\t" | |
237 | "sltu\t$1, %0, %1\n\t" | |
238 | ||
239 | "lw\t%1, 12(%3)\n\t" | |
240 | "addu\t%0, $1\n\t" | |
241 | "addu\t%0, %1\n\t" | |
242 | "sltu\t$1, %0, %1\n\t" | |
243 | ||
244 | "addu\t%0, $1\t\t\t# Add final carry\n\t" | |
245 | ".set\tpop" | |
246 | : "=r" (sum), "=r" (proto) | |
247 | : "r" (saddr), "r" (daddr), | |
248 | "0" (htonl(len)), "1" (htonl(proto)), "r" (sum)); | |
249 | ||
250 | return csum_fold(sum); | |
251 | } | |
252 | ||
253 | #endif /* _ASM_CHECKSUM_H */ |