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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/in6.h>
15
16#include <asm/uaccess.h>
17
18/*
19 * computes the checksum of a memory block at buff, length len,
20 * and adds in "sum" (32-bit)
21 *
22 * returns a 32-bit number suitable for feeding into itself
23 * or csum_tcpudp_magic
24 *
25 * this function must be called with even lengths, except
26 * for the last fragment, which may be odd
27 *
28 * it's best to have buff aligned on a 32-bit boundary
29 */
Al Viro8e3d8432006-11-14 21:18:18 -080030__wsum csum_partial(const void *buff, int len, __wsum sum);
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
Atsushi Nemotof860c902006-12-13 01:22:06 +090032__wsum __csum_partial_copy_user(const void *src, void *dst,
33 int len, __wsum sum, int *err_ptr);
34
Linus Torvalds1da177e2005-04-16 15:20:36 -070035/*
36 * this is a new version of the above that records errors it finds in *errp,
37 * but continues and zeros the rest of the buffer.
38 */
Atsushi Nemotof860c902006-12-13 01:22:06 +090039static inline
40__wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len,
41 __wsum sum, int *err_ptr)
42{
43 might_sleep();
44 return __csum_partial_copy_user((__force void *)src, dst,
45 len, sum, err_ptr);
46}
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
48/*
49 * Copy and checksum to user
50 */
51#define HAVE_CSUM_COPY_USER
Atsushi Nemotof860c902006-12-13 01:22:06 +090052static inline
53__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
54 __wsum sum, int *err_ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070055{
56 might_sleep();
Atsushi Nemotof860c902006-12-13 01:22:06 +090057 if (access_ok(VERIFY_WRITE, dst, len))
58 return __csum_partial_copy_user(src, (__force void *)dst,
59 len, sum, err_ptr);
60 if (len)
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 *err_ptr = -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
Atsushi Nemotof860c902006-12-13 01:22:06 +090063 return (__force __wsum)-1; /* invalid checksum */
Linus Torvalds1da177e2005-04-16 15:20:36 -070064}
65
66/*
67 * the same as csum_partial, but copies from user space (but on MIPS
68 * we have just one address space, so this is identical to the above)
69 */
Al Viro8e3d8432006-11-14 21:18:18 -080070__wsum csum_partial_copy_nocheck(const void *src, void *dst,
71 int len, __wsum sum);
Linus Torvalds1da177e2005-04-16 15:20:36 -070072
73/*
74 * Fold a partial checksum without adding pseudo headers
75 */
Al Viro8e3d8432006-11-14 21:18:18 -080076static inline __sum16 csum_fold(__wsum sum)
Linus Torvalds1da177e2005-04-16 15:20:36 -070077{
78 __asm__(
Thiemo Seufer04988d6f2005-07-08 09:17:05 +000079 " .set push # csum_fold\n"
80 " .set noat \n"
81 " sll $1, %0, 16 \n"
82 " addu %0, $1 \n"
83 " sltu $1, %0, $1 \n"
84 " srl %0, %0, 16 \n"
85 " addu %0, $1 \n"
86 " xori %0, 0xffff \n"
87 " .set pop"
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 : "=r" (sum)
89 : "0" (sum));
90
Al Viro8e3d8432006-11-14 21:18:18 -080091 return (__force __sum16)sum;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092}
93
94/*
95 * This is a version of ip_compute_csum() optimized for IP headers,
96 * which always checksum on 4 octet boundaries.
97 *
98 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
99 * Arnt Gulbrandsen.
100 */
Al Viro8e3d8432006-11-14 21:18:18 -0800101static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102{
Al Viro8e3d8432006-11-14 21:18:18 -0800103 const unsigned int *word = iph;
104 const unsigned int *stop = word + ihl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 unsigned int csum;
106 int carry;
107
108 csum = word[0];
109 csum += word[1];
110 carry = (csum < word[1]);
111 csum += carry;
112
113 csum += word[2];
114 carry = (csum < word[2]);
115 csum += carry;
116
117 csum += word[3];
118 carry = (csum < word[3]);
119 csum += carry;
120
121 word += 4;
122 do {
123 csum += *word;
124 carry = (csum < *word);
125 csum += carry;
126 word++;
127 } while (word != stop);
128
129 return csum_fold(csum);
130}
131
Al Viro8e3d8432006-11-14 21:18:18 -0800132static inline __wsum csum_tcpudp_nofold(__be32 saddr,
133 __be32 daddr, unsigned short len, unsigned short proto,
134 __wsum sum)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135{
136 __asm__(
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000137 " .set push # csum_tcpudp_nofold\n"
138 " .set noat \n"
Ralf Baechle875d43e2005-09-03 15:56:16 -0700139#ifdef CONFIG_32BIT
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000140 " addu %0, %2 \n"
141 " sltu $1, %0, %2 \n"
142 " addu %0, $1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000144 " addu %0, %3 \n"
145 " sltu $1, %0, %3 \n"
146 " addu %0, $1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000148 " addu %0, %4 \n"
149 " sltu $1, %0, %4 \n"
150 " addu %0, $1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151#endif
Ralf Baechle875d43e2005-09-03 15:56:16 -0700152#ifdef CONFIG_64BIT
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000153 " daddu %0, %2 \n"
154 " daddu %0, %3 \n"
155 " daddu %0, %4 \n"
156 " dsll32 $1, %0, 0 \n"
157 " daddu %0, $1 \n"
Ralf Baechlee9728832005-09-20 10:56:26 +0000158 " dsra32 %0, %0, 0 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159#endif
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000160 " .set pop"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 : "=r" (sum)
Atsushi Nemoto66218da2007-01-24 15:43:34 +0900162 : "0" ((__force unsigned long)daddr),
163 "r" ((__force unsigned long)saddr),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164#ifdef __MIPSEL__
Al Viro8e3d8432006-11-14 21:18:18 -0800165 "r" ((proto + len) << 8),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166#else
Al Viro8e3d8432006-11-14 21:18:18 -0800167 "r" (proto + len),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168#endif
169 "r" (sum));
170
171 return sum;
172}
173
174/*
175 * computes the checksum of the TCP/UDP pseudo-header
176 * returns a 16-bit checksum, already complemented
177 */
Al Viro8e3d8432006-11-14 21:18:18 -0800178static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 unsigned short len,
180 unsigned short proto,
Al Viro8e3d8432006-11-14 21:18:18 -0800181 __wsum sum)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182{
183 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
184}
185
186/*
187 * this routine is used for miscellaneous IP-like checksums, mainly
188 * in icmp.c
189 */
Al Viro8e3d8432006-11-14 21:18:18 -0800190static inline __sum16 ip_compute_csum(const void *buff, int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191{
192 return csum_fold(csum_partial(buff, len, 0));
193}
194
195#define _HAVE_ARCH_IPV6_CSUM
Al Viro8e3d8432006-11-14 21:18:18 -0800196static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
197 const struct in6_addr *daddr,
198 __u32 len, unsigned short proto,
199 __wsum sum)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200{
201 __asm__(
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000202 " .set push # csum_ipv6_magic\n"
203 " .set noreorder \n"
204 " .set noat \n"
205 " addu %0, %5 # proto (long in network byte order)\n"
206 " sltu $1, %0, %5 \n"
207 " addu %0, $1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000209 " addu %0, %6 # csum\n"
210 " sltu $1, %0, %6 \n"
211 " lw %1, 0(%2) # four words source address\n"
212 " addu %0, $1 \n"
213 " addu %0, %1 \n"
214 " sltu $1, %0, %1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000216 " lw %1, 4(%2) \n"
217 " addu %0, $1 \n"
218 " addu %0, %1 \n"
219 " sltu $1, %0, %1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000221 " lw %1, 8(%2) \n"
222 " addu %0, $1 \n"
223 " addu %0, %1 \n"
224 " sltu $1, %0, %1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000226 " lw %1, 12(%2) \n"
227 " addu %0, $1 \n"
228 " addu %0, %1 \n"
229 " sltu $1, %0, %1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000231 " lw %1, 0(%3) \n"
232 " addu %0, $1 \n"
233 " addu %0, %1 \n"
234 " sltu $1, %0, %1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000236 " lw %1, 4(%3) \n"
237 " addu %0, $1 \n"
238 " addu %0, %1 \n"
239 " sltu $1, %0, %1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000241 " lw %1, 8(%3) \n"
242 " addu %0, $1 \n"
243 " addu %0, %1 \n"
244 " sltu $1, %0, %1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000246 " lw %1, 12(%3) \n"
247 " addu %0, $1 \n"
248 " addu %0, %1 \n"
249 " sltu $1, %0, %1 \n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250
Thiemo Seufer04988d6f2005-07-08 09:17:05 +0000251 " addu %0, $1 # Add final carry\n"
252 " .set pop"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 : "=r" (sum), "=r" (proto)
254 : "r" (saddr), "r" (daddr),
255 "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
256
257 return csum_fold(sum);
258}
259
260#endif /* _ASM_CHECKSUM_H */