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
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
11 #ifndef _ASM_CHECKSUM_H
12 #define _ASM_CHECKSUM_H
14 #include <linux/in6.h>
16 #include <asm/uaccess.h>
19 * computes the checksum of a memory block at buff, length len,
20 * and adds in "sum" (32-bit)
22 * returns a 32-bit number suitable for feeding into itself
23 * or csum_tcpudp_magic
25 * this function must be called with even lengths, except
26 * for the last fragment, which may be odd
28 * it's best to have buff aligned on a 32-bit boundary
30 __wsum
csum_partial(const void *buff
, int len
, __wsum sum
);
32 __wsum
__csum_partial_copy_user(const void *src
, void *dst
,
33 int len
, __wsum sum
, int *err_ptr
);
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.
40 __wsum
csum_partial_copy_from_user(const void __user
*src
, void *dst
, int len
,
41 __wsum sum
, int *err_ptr
)
44 return __csum_partial_copy_user((__force
void *)src
, dst
,
49 * Copy and checksum to user
51 #define HAVE_CSUM_COPY_USER
53 __wsum
csum_and_copy_to_user(const void *src
, void __user
*dst
, int len
,
54 __wsum sum
, int *err_ptr
)
57 if (access_ok(VERIFY_WRITE
, dst
, len
))
58 return __csum_partial_copy_user(src
, (__force
void *)dst
,
63 return (__force __wsum
)-1; /* invalid checksum */
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)
70 __wsum
csum_partial_copy_nocheck(const void *src
, void *dst
,
74 * Fold a partial checksum without adding pseudo headers
76 static inline __sum16
csum_fold(__wsum sum
)
79 " .set push # csum_fold\n"
91 return (__force __sum16
)sum
;
95 * This is a version of ip_compute_csum() optimized for IP headers,
96 * which always checksum on 4 octet boundaries.
98 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
101 static inline __sum16
ip_fast_csum(const void *iph
, unsigned int ihl
)
103 const unsigned int *word
= iph
;
104 const unsigned int *stop
= word
+ ihl
;
110 carry
= (csum
< word
[1]);
114 carry
= (csum
< word
[2]);
118 carry
= (csum
< word
[3]);
124 carry
= (csum
< *word
);
127 } while (word
!= stop
);
129 return csum_fold(csum
);
132 static inline __wsum
csum_tcpudp_nofold(__be32 saddr
,
133 __be32 daddr
, unsigned short len
, unsigned short proto
,
137 " .set push # csum_tcpudp_nofold\n"
141 " sltu $1, %0, %2 \n"
145 " sltu $1, %0, %3 \n"
149 " sltu $1, %0, %4 \n"
156 " dsll32 $1, %0, 0 \n"
158 " dsra32 %0, %0, 0 \n"
162 : "0" ((__force
unsigned long)daddr
),
163 "r" ((__force
unsigned long)saddr
),
165 "r" ((proto
+ len
) << 8),
175 * computes the checksum of the TCP/UDP pseudo-header
176 * returns a 16-bit checksum, already complemented
178 static inline __sum16
csum_tcpudp_magic(__be32 saddr
, __be32 daddr
,
180 unsigned short proto
,
183 return csum_fold(csum_tcpudp_nofold(saddr
, daddr
, len
, proto
, sum
));
187 * this routine is used for miscellaneous IP-like checksums, mainly
190 static inline __sum16
ip_compute_csum(const void *buff
, int len
)
192 return csum_fold(csum_partial(buff
, len
, 0));
195 #define _HAVE_ARCH_IPV6_CSUM
196 static __inline__ __sum16
csum_ipv6_magic(const struct in6_addr
*saddr
,
197 const struct in6_addr
*daddr
,
198 __u32 len
, unsigned short proto
,
202 " .set push # csum_ipv6_magic\n"
205 " addu %0, %5 # proto (long in network byte order)\n"
206 " sltu $1, %0, %5 \n"
209 " addu %0, %6 # csum\n"
210 " sltu $1, %0, %6 \n"
211 " lw %1, 0(%2) # four words source address\n"
214 " sltu $1, %0, %1 \n"
219 " sltu $1, %0, %1 \n"
224 " sltu $1, %0, %1 \n"
229 " sltu $1, %0, %1 \n"
234 " sltu $1, %0, %1 \n"
239 " sltu $1, %0, %1 \n"
244 " sltu $1, %0, %1 \n"
249 " sltu $1, %0, %1 \n"
251 " addu %0, $1 # Add final carry\n"
253 : "=r" (sum
), "=r" (proto
)
254 : "r" (saddr
), "r" (daddr
),
255 "0" (htonl(len
)), "1" (htonl(proto
)), "r" (sum
));
257 return csum_fold(sum
);
260 #endif /* _ASM_CHECKSUM_H */