tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#ifdef __KERNEL__
2#ifndef _PPC_CHECKSUM_H
3#define _PPC_CHECKSUM_H
4
5
6/*
7 * computes the checksum of a memory block at buff, length len,
8 * and adds in "sum" (32-bit)
9 *
10 * returns a 32-bit number suitable for feeding into itself
11 * or csum_tcpudp_magic
12 *
13 * this function must be called with even lengths, except
14 * for the last fragment, which may be odd
15 *
16 * it's best to have buff aligned on a 32-bit boundary
17 */
18extern unsigned int csum_partial(const unsigned char * buff, int len,
19 unsigned int sum);
20
21/*
22 * Computes the checksum of a memory block at src, length len,
23 * and adds in "sum" (32-bit), while copying the block to dst.
24 * If an access exception occurs on src or dst, it stores -EFAULT
25 * to *src_err or *dst_err respectively (if that pointer is not
26 * NULL), and, for an error on src, zeroes the rest of dst.
27 *
28 * Like csum_partial, this must be called with even lengths,
29 * except for the last fragment.
30 */
31extern unsigned int csum_partial_copy_generic(const char *src, char *dst,
32 int len, unsigned int sum,
33 int *src_err, int *dst_err);
34
35#define csum_partial_copy_from_user(src, dst, len, sum, errp) \
36 csum_partial_copy_generic((__force void *)(src), (dst), (len), (sum), (errp), NULL)
37
38/* FIXME: this needs to be written to really do no check -- Cort */
39#define csum_partial_copy_nocheck(src, dst, len, sum) \
40 csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
41
42/*
43 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
44 * 1's complement 16-bit checksum.
45 */
46static inline unsigned int csum_fold(unsigned int sum)
47{
48 unsigned int tmp;
49
50 /* swap the two 16-bit halves of sum */
51 __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
52 /* if there is a carry from adding the two 16-bit halves,
53 it will carry from the lower half into the upper half,
54 giving us the correct sum in the upper half. */
55 sum = ~(sum + tmp) >> 16;
56 return sum;
57}
58
59/*
60 * this routine is used for miscellaneous IP-like checksums, mainly
61 * in icmp.c
62 */
63static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
64{
65 return csum_fold(csum_partial(buff, len, 0));
66}
67
68/*
69 * FIXME: I swiped this one from the sparc and made minor modifications.
70 * It may not be correct. -- Cort
71 */
72static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
73 unsigned long daddr,
74 unsigned short len,
75 unsigned short proto,
76 unsigned int sum)
77{
78 __asm__("\n\
79 addc %0,%0,%1 \n\
80 adde %0,%0,%2 \n\
81 adde %0,%0,%3 \n\
82 addze %0,%0 \n\
83 "
84 : "=r" (sum)
85 : "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum));
86 return sum;
87}
88
89/*
90 * This is a version of ip_compute_csum() optimized for IP headers,
91 * which always checksum on 4 octet boundaries. ihl is the number
92 * of 32-bit words and is always >= 5.
93 */
94extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl);
95
96/*
97 * computes the checksum of the TCP/UDP pseudo-header
98 * returns a 16-bit checksum, already complemented
99 */
100extern unsigned short csum_tcpudp_magic(unsigned long saddr,
101 unsigned long daddr,
102 unsigned short len,
103 unsigned short proto,
104 unsigned int sum);
105
106#endif
107#endif /* __KERNEL__ */