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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _I386_CHECKSUM_H
2#define _I386_CHECKSUM_H
3
4#include <linux/in6.h>
5
Alexey Dobriyana9ed8812005-06-23 00:08:32 -07006#include <asm/uaccess.h>
7
Linus Torvalds1da177e2005-04-16 15:20:36 -07008/*
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 */
Al Viro72685fc2006-11-14 21:21:37 -080020asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
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
Al Viro72685fc2006-11-14 21:21:37 -080030asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
Joe Perches0883e912008-03-23 01:01:49 -070031 int len, __wsum sum,
32 int *src_err_ptr, int *dst_err_ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
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
Jesper Juhle49332b2005-05-01 08:59:08 -070039 * access_ok().
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 */
Joe Perches0883e912008-03-23 01:01:49 -070041static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst,
42 int len, __wsum sum)
Linus Torvalds1da177e2005-04-16 15:20:36 -070043{
Joe Perches0883e912008-03-23 01:01:49 -070044 return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070045}
46
Joe Perches0883e912008-03-23 01:01:49 -070047static inline __wsum csum_partial_copy_from_user(const void __user *src,
48 void *dst,
49 int len, __wsum sum,
50 int *err_ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070051{
52 might_sleep();
Al Viro72685fc2006-11-14 21:21:37 -080053 return csum_partial_copy_generic((__force void *)src, dst,
Joe Perches0883e912008-03-23 01:01:49 -070054 len, sum, err_ptr, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070055}
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 */
Al Viro72685fc2006-11-14 21:21:37 -080064static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
Linus Torvalds1da177e2005-04-16 15:20:36 -070065{
66 unsigned int sum;
67
Joe Perches0883e912008-03-23 01:01:49 -070068 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"
Thomas Graf2c656492005-08-20 17:24:25 -070085 /* Since the input registers which are loaded with iph and ihl
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 are modified, we must also specify them as outputs, or gcc
87 will assume they contain their original values. */
Joe Perches0883e912008-03-23 01:01:49 -070088 : "=r" (sum), "=r" (iph), "=r" (ihl)
89 : "1" (iph), "2" (ihl)
90 : "memory");
Al Viro72685fc2006-11-14 21:21:37 -080091 return (__force __sum16)sum;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092}
93
94/*
95 * Fold a partial checksum
96 */
97
Al Viro72685fc2006-11-14 21:21:37 -080098static inline __sum16 csum_fold(__wsum sum)
Linus Torvalds1da177e2005-04-16 15:20:36 -070099{
Joe Perches0883e912008-03-23 01:01:49 -0700100 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));
Al Viro72685fc2006-11-14 21:21:37 -0800105 return (__force __sum16)(~(__force u32)sum >> 16);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106}
107
Al Viro72685fc2006-11-14 21:21:37 -0800108static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
Joe Perches0883e912008-03-23 01:01:49 -0700109 unsigned short len,
110 unsigned short proto,
111 __wsum sum)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112{
Joe Perches0883e912008-03-23 01:01:49 -0700113 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121}
122
123/*
124 * computes the checksum of the TCP/UDP pseudo-header
125 * returns a 16-bit checksum, already complemented
126 */
Al Viro72685fc2006-11-14 21:21:37 -0800127static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
Joe Perches0883e912008-03-23 01:01:49 -0700128 unsigned short len,
129 unsigned short proto,
130 __wsum sum)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131{
Joe Perches0883e912008-03-23 01:01:49 -0700132 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133}
134
135/*
136 * this routine is used for miscellaneous IP-like checksums, mainly
137 * in icmp.c
138 */
139
Al Viro72685fc2006-11-14 21:21:37 -0800140static inline __sum16 ip_compute_csum(const void *buff, int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141{
Joe Perches0883e912008-03-23 01:01:49 -0700142 return csum_fold(csum_partial(buff, len, 0));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143}
144
145#define _HAVE_ARCH_IPV6_CSUM
Joe Perches0883e912008-03-23 01:01:49 -0700146static 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)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150{
Joe Perches0883e912008-03-23 01:01:49 -0700151 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));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
166 return csum_fold(sum);
167}
168
169/*
170 * Copy and checksum to user
171 */
172#define HAVE_CSUM_COPY_USER
Joe Perches0883e912008-03-23 01:01:49 -0700173static inline __wsum csum_and_copy_to_user(const void *src,
174 void __user *dst,
175 int len, __wsum sum,
176 int *err_ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177{
178 might_sleep();
179 if (access_ok(VERIFY_WRITE, dst, len))
Joe Perches0883e912008-03-23 01:01:49 -0700180 return csum_partial_copy_generic(src, (__force void *)dst,
181 len, sum, NULL, err_ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182
183 if (len)
184 *err_ptr = -EFAULT;
185
Al Viro72685fc2006-11-14 21:21:37 -0800186 return (__force __wsum)-1; /* invalid checksum */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187}
188
189#endif