blob: d76a5f081c912e65ab12baceebb1114235875963 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001#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 */
18asmlinkage 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
28asmlinkage 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 */
38static __inline__
39unsigned 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
45static __inline__
46unsigned 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 */
61static 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
97static 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
108static 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 */
128static 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
142static 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
148static __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
177static __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