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Linux kernel mirror (for testing)
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linux
1#ifndef _ASM_POWERPC_CHECKSUM_H
2#define _ASM_POWERPC_CHECKSUM_H
3#ifdef __KERNEL__
4
5/*
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.
10 */
11
12/*
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.
16 */
17extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl);
18
19/*
20 * computes the checksum of the TCP/UDP pseudo-header
21 * returns a 16-bit checksum, already complemented
22 */
23extern unsigned short csum_tcpudp_magic(unsigned long saddr,
24 unsigned long daddr,
25 unsigned short len,
26 unsigned short proto,
27 unsigned int sum);
28
29/*
30 * computes the checksum of a memory block at buff, length len,
31 * and adds in "sum" (32-bit)
32 *
33 * returns a 32-bit number suitable for feeding into itself
34 * or csum_tcpudp_magic
35 *
36 * this function must be called with even lengths, except
37 * for the last fragment, which may be odd
38 *
39 * it's best to have buff aligned on a 32-bit boundary
40 */
41extern unsigned int csum_partial(const unsigned char * buff, int len,
42 unsigned int sum);
43
44/*
45 * Computes the checksum of a memory block at src, length len,
46 * and adds in "sum" (32-bit), while copying the block to dst.
47 * If an access exception occurs on src or dst, it stores -EFAULT
48 * to *src_err or *dst_err respectively (if that pointer is not
49 * NULL), and, for an error on src, zeroes the rest of dst.
50 *
51 * Like csum_partial, this must be called with even lengths,
52 * except for the last fragment.
53 */
54extern unsigned int csum_partial_copy_generic(const char *src, char *dst,
55 int len, unsigned int sum,
56 int *src_err, int *dst_err);
57/*
58 * the same as csum_partial, but copies from src to dst while it
59 * checksums.
60 */
61unsigned int csum_partial_copy_nocheck(const char *src,
62 char *dst,
63 int len,
64 unsigned int sum);
65
66#define csum_partial_copy_from_user(src, dst, len, sum, errp) \
67 csum_partial_copy_generic((src), (dst), (len), (sum), (errp), NULL)
68
69#define csum_partial_copy_nocheck(src, dst, len, sum) \
70 csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
71
72
73/*
74 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
75 * 1's complement 16-bit checksum.
76 */
77static inline unsigned int csum_fold(unsigned int sum)
78{
79 unsigned int tmp;
80
81 /* swap the two 16-bit halves of sum */
82 __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
83 /* if there is a carry from adding the two 16-bit halves,
84 it will carry from the lower half into the upper half,
85 giving us the correct sum in the upper half. */
86 sum = ~(sum + tmp) >> 16;
87 return sum;
88}
89
90/*
91 * this routine is used for miscellaneous IP-like checksums, mainly
92 * in icmp.c
93 */
94static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
95{
96 return csum_fold(csum_partial(buff, len, 0));
97}
98
99#ifdef __powerpc64__
100static inline u32 csum_tcpudp_nofold(u32 saddr,
101 u32 daddr,
102 unsigned short len,
103 unsigned short proto,
104 unsigned int sum)
105{
106 unsigned long s = sum;
107
108 s += saddr;
109 s += daddr;
110 s += (proto << 16) + len;
111 s += (s >> 32);
112 return (u32) s;
113}
114#else
115static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
116 unsigned long daddr,
117 unsigned short len,
118 unsigned short proto,
119 unsigned int sum)
120{
121 __asm__("\n\
122 addc %0,%0,%1 \n\
123 adde %0,%0,%2 \n\
124 adde %0,%0,%3 \n\
125 addze %0,%0 \n\
126 "
127 : "=r" (sum)
128 : "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum));
129 return sum;
130}
131
132#endif
133#endif /* __KERNEL__ */
134#endif