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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
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
12 * This is a version of ip_compute_csum() optimized for IP headers,
13 * which always checksum on 4 octet boundaries. ihl is the number
14 * of 32-bit words and is always >= 5.
16 extern unsigned short ip_fast_csum(unsigned char * iph
, unsigned int ihl
);
19 * computes the checksum of the TCP/UDP pseudo-header
20 * returns a 16-bit checksum, already complemented
22 extern unsigned short csum_tcpudp_magic(unsigned long saddr
,
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 unsigned int csum_partial(const unsigned char * buff
, int len
,
44 * Computes the checksum of a memory block at src, length len,
45 * and adds in "sum" (32-bit), while copying the block to dst.
46 * If an access exception occurs on src or dst, it stores -EFAULT
47 * to *src_err or *dst_err respectively (if that pointer is not
48 * NULL), and, for an error on src, zeroes the rest of dst.
50 * Like csum_partial, this must be called with even lengths,
51 * except for the last fragment.
53 extern unsigned int csum_partial_copy_generic(const char *src
, char *dst
,
54 int len
, unsigned int sum
,
55 int *src_err
, int *dst_err
);
57 * the same as csum_partial, but copies from src to dst while it
60 unsigned int csum_partial_copy_nocheck(const char *src
,
65 #define csum_partial_copy_from_user(src, dst, len, sum, errp) \
66 csum_partial_copy_generic((src), (dst), (len), (sum), (errp), NULL)
68 #define csum_partial_copy_nocheck(src, dst, len, sum) \
69 csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
73 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
74 * 1's complement 16-bit checksum.
76 static inline unsigned int csum_fold(unsigned int sum
)
80 /* swap the two 16-bit halves of sum */
81 __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp
) : "r" (sum
));
82 /* if there is a carry from adding the two 16-bit halves,
83 it will carry from the lower half into the upper half,
84 giving us the correct sum in the upper half. */
85 sum
= ~(sum
+ tmp
) >> 16;
90 * this routine is used for miscellaneous IP-like checksums, mainly
93 static inline unsigned short ip_compute_csum(unsigned char * buff
, int len
)
95 return csum_fold(csum_partial(buff
, len
, 0));
99 static inline u32
csum_tcpudp_nofold(u32 saddr
,
102 unsigned short proto
,
105 unsigned long s
= sum
;
109 s
+= (proto
<< 16) + len
;
114 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr
,
117 unsigned short proto
,
127 : "r" (daddr
), "r"(saddr
), "r"((proto
<<16)+len
), "0"(sum
));