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1#ifndef __ASM_SH_CHECKSUM_H
2#define __ASM_SH_CHECKSUM_H
3
4/*
5 * This file is subject to the terms and conditions of the GNU General Public
6 * License. See the file "COPYING" in the main directory of this archive
7 * for more details.
8 *
9 * Copyright (C) 1999 by Kaz Kojima & Niibe Yutaka
10 */
11
12#include <linux/config.h>
13#include <linux/in6.h>
14
15/*
16 * computes the checksum of a memory block at buff, length len,
17 * and adds in "sum" (32-bit)
18 *
19 * returns a 32-bit number suitable for feeding into itself
20 * or csum_tcpudp_magic
21 *
22 * this function must be called with even lengths, except
23 * for the last fragment, which may be odd
24 *
25 * it's best to have buff aligned on a 32-bit boundary
26 */
27asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
28
29/*
30 * the same as csum_partial, but copies from src while it
31 * checksums, and handles user-space pointer exceptions correctly, when needed.
32 *
33 * here even more important to align src and dst on a 32-bit (or even
34 * better 64-bit) boundary
35 */
36
37asmlinkage unsigned int csum_partial_copy_generic(const unsigned char *src, unsigned char *dst,
38 int len, int sum, int *src_err_ptr, int *dst_err_ptr);
39
40/*
41 * Note: when you get a NULL pointer exception here this means someone
42 * passed in an incorrect kernel address to one of these functions.
43 *
44 * If you use these functions directly please don't forget the
45 * access_ok().
46 */
47static __inline__
48unsigned int csum_partial_copy_nocheck (const unsigned char *src, unsigned char *dst,
49 int len, int sum)
50{
51 return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
52}
53
54static __inline__
55unsigned int csum_partial_copy_from_user (const unsigned char *src, unsigned char *dst,
56 int len, int sum, int *err_ptr)
57{
58 return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);
59}
60
61/*
62 * Fold a partial checksum
63 */
64
65static __inline__ unsigned int csum_fold(unsigned int sum)
66{
67 unsigned int __dummy;
68 __asm__("swap.w %0, %1\n\t"
69 "extu.w %0, %0\n\t"
70 "extu.w %1, %1\n\t"
71 "add %1, %0\n\t"
72 "swap.w %0, %1\n\t"
73 "add %1, %0\n\t"
74 "not %0, %0\n\t"
75 : "=r" (sum), "=&r" (__dummy)
76 : "0" (sum)
77 : "t");
78 return sum;
79}
80
81/*
82 * This is a version of ip_compute_csum() optimized for IP headers,
83 * which always checksum on 4 octet boundaries.
84 *
85 * i386 version by Jorge Cwik <jorge@laser.satlink.net>, adapted
86 * for linux by * Arnt Gulbrandsen.
87 */
88static __inline__ unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl)
89{
90 unsigned int sum, __dummy0, __dummy1;
91
92 __asm__ __volatile__(
93 "mov.l @%1+, %0\n\t"
94 "mov.l @%1+, %3\n\t"
95 "add #-2, %2\n\t"
96 "clrt\n\t"
97 "1:\t"
98 "addc %3, %0\n\t"
99 "movt %4\n\t"
100 "mov.l @%1+, %3\n\t"
101 "dt %2\n\t"
102 "bf/s 1b\n\t"
103 " cmp/eq #1, %4\n\t"
104 "addc %3, %0\n\t"
105 "addc %2, %0" /* Here %2 is 0, add carry-bit */
106 /* Since the input registers which are loaded with iph and ihl
107 are modified, we must also specify them as outputs, or gcc
108 will assume they contain their original values. */
109 : "=r" (sum), "=r" (iph), "=r" (ihl), "=&r" (__dummy0), "=&z" (__dummy1)
110 : "1" (iph), "2" (ihl)
111 : "t");
112
113 return csum_fold(sum);
114}
115
116static __inline__ unsigned long csum_tcpudp_nofold(unsigned long saddr,
117 unsigned long daddr,
118 unsigned short len,
119 unsigned short proto,
120 unsigned int sum)
121{
122#ifdef __LITTLE_ENDIAN__
123 unsigned long len_proto = (ntohs(len)<<16)+proto*256;
124#else
125 unsigned long len_proto = (proto<<16)+len;
126#endif
127 __asm__("clrt\n\t"
128 "addc %0, %1\n\t"
129 "addc %2, %1\n\t"
130 "addc %3, %1\n\t"
131 "movt %0\n\t"
132 "add %1, %0"
133 : "=r" (sum), "=r" (len_proto)
134 : "r" (daddr), "r" (saddr), "1" (len_proto), "0" (sum)
135 : "t");
136 return sum;
137}
138
139/*
140 * computes the checksum of the TCP/UDP pseudo-header
141 * returns a 16-bit checksum, already complemented
142 */
143static __inline__ unsigned short int csum_tcpudp_magic(unsigned long saddr,
144 unsigned long daddr,
145 unsigned short len,
146 unsigned short proto,
147 unsigned int sum)
148{
149 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
150}
151
152/*
153 * this routine is used for miscellaneous IP-like checksums, mainly
154 * in icmp.c
155 */
156
157static __inline__ unsigned short ip_compute_csum(unsigned char * buff, int len)
158{
159 return csum_fold (csum_partial(buff, len, 0));
160}
161
162#define _HAVE_ARCH_IPV6_CSUM
163static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
164 struct in6_addr *daddr,
165 __u32 len,
166 unsigned short proto,
167 unsigned int sum)
168{
169 unsigned int __dummy;
170 __asm__("clrt\n\t"
171 "mov.l @(0,%2), %1\n\t"
172 "addc %1, %0\n\t"
173 "mov.l @(4,%2), %1\n\t"
174 "addc %1, %0\n\t"
175 "mov.l @(8,%2), %1\n\t"
176 "addc %1, %0\n\t"
177 "mov.l @(12,%2), %1\n\t"
178 "addc %1, %0\n\t"
179 "mov.l @(0,%3), %1\n\t"
180 "addc %1, %0\n\t"
181 "mov.l @(4,%3), %1\n\t"
182 "addc %1, %0\n\t"
183 "mov.l @(8,%3), %1\n\t"
184 "addc %1, %0\n\t"
185 "mov.l @(12,%3), %1\n\t"
186 "addc %1, %0\n\t"
187 "addc %4, %0\n\t"
188 "addc %5, %0\n\t"
189 "movt %1\n\t"
190 "add %1, %0\n"
191 : "=r" (sum), "=&r" (__dummy)
192 : "r" (saddr), "r" (daddr),
193 "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
194 : "t");
195
196 return csum_fold(sum);
197}
198
199/*
200 * Copy and checksum to user
201 */
202#define HAVE_CSUM_COPY_USER
203static __inline__ unsigned int csum_and_copy_to_user (const unsigned char *src,
204 unsigned char __user *dst,
205 int len, int sum,
206 int *err_ptr)
207{
208 if (access_ok(VERIFY_WRITE, dst, len))
209 return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
210
211 if (len)
212 *err_ptr = -EFAULT;
213
214 return -1; /* invalid checksum */
215}
216#endif /* __ASM_SH_CHECKSUM_H */