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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - include/asm-powerpc/checksum.h
1 #ifndef _ASM_POWERPC_CHECKSUM_H
2 #define _ASM_POWERPC_CHECKSUM_H
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
13 * This is a version of ip_compute_csum() optimized for IP headers,
14 * which always checksum on 4 octet boundaries. ihl is the number
15 * of 32-bit words and is always >= 5.
17 extern __sum16
ip_fast_csum(const void *iph
, unsigned int ihl
);
20 * computes the checksum of the TCP/UDP pseudo-header
21 * returns a 16-bit checksum, already complemented
23 extern __sum16
csum_tcpudp_magic(__be32 saddr
, __be32 daddr
,
29 * computes the checksum of a memory block at buff, length len,
30 * and adds in "sum" (32-bit)
32 * returns a 32-bit number suitable for feeding into itself
33 * or csum_tcpudp_magic
35 * this function must be called with even lengths, except
36 * for the last fragment, which may be odd
38 * it's best to have buff aligned on a 32-bit boundary
40 extern __wsum
csum_partial(const void *buff
, int len
, __wsum sum
);
43 * Computes the checksum of a memory block at src, length len,
44 * and adds in "sum" (32-bit), while copying the block to dst.
45 * If an access exception occurs on src or dst, it stores -EFAULT
46 * to *src_err or *dst_err respectively (if that pointer is not
47 * NULL), and, for an error on src, zeroes the rest of dst.
49 * Like csum_partial, this must be called with even lengths,
50 * except for the last fragment.
52 extern __wsum
csum_partial_copy_generic(const void *src
, void *dst
,
54 int *src_err
, int *dst_err
);
56 * the same as csum_partial, but copies from src to dst while it
59 #define csum_partial_copy_from_user(src, dst, len, sum, errp) \
60 csum_partial_copy_generic((__force const void *)(src), (dst), (len), (sum), (errp), NULL)
62 #define csum_partial_copy_nocheck(src, dst, len, sum) \
63 csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
67 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
68 * 1's complement 16-bit checksum.
70 static inline __sum16
csum_fold(__wsum sum
)
74 /* swap the two 16-bit halves of sum */
75 __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp
) : "r" (sum
));
76 /* if there is a carry from adding the two 16-bit halves,
77 it will carry from the lower half into the upper half,
78 giving us the correct sum in the upper half. */
79 return (__force __sum16
)(~((__force u32
)sum
+ tmp
) >> 16);
83 * this routine is used for miscellaneous IP-like checksums, mainly
86 static inline __sum16
ip_compute_csum(const void *buff
, int len
)
88 return csum_fold(csum_partial(buff
, len
, 0));
91 static inline __wsum
csum_tcpudp_nofold(__be32 saddr
, __be32 daddr
,
97 unsigned long s
= (__force u32
)sum
;
99 s
+= (__force u32
)saddr
;
100 s
+= (__force u32
)daddr
;
103 return (__force __wsum
) s
;
112 : "r" (daddr
), "r"(saddr
), "r"(proto
+ len
), "0"(sum
));
116 #endif /* __KERNEL__ */