1#ifndef _PPC64_CHECKSUM_H
2#define _PPC64_CHECKSUM_H
3
4/*
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.
9 */
10
11/*
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.
15 */
16extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl);
17
18/*
19 * computes the checksum of the TCP/UDP pseudo-header
20 * returns a 16-bit checksum, already complemented
21 */
22extern unsigned short csum_tcpudp_magic(unsigned long saddr,
23					unsigned long daddr,
24					unsigned short len,
25					unsigned short proto,
26					unsigned int sum);
27
28/*
29 * computes the checksum of a memory block at buff, length len,
30 * and adds in "sum" (32-bit)
31 *
32 * returns a 32-bit number suitable for feeding into itself
33 * or csum_tcpudp_magic
34 *
35 * this function must be called with even lengths, except
36 * for the last fragment, which may be odd
37 *
38 * it's best to have buff aligned on a 32-bit boundary
39 */
40extern unsigned int csum_partial(const unsigned char * buff, int len,
41				 unsigned int sum);
42
43/*
44 * the same as csum_partial, but copies from src to dst while it
45 * checksums
46 */
47unsigned int csum_partial_copy(const char *src, char *dst,
48			       int len, unsigned int sum);
49
50extern unsigned int csum_partial_copy_generic(const char *src, char *dst,
51					      int len, unsigned int sum,
52					      int *src_err, int *dst_err);
53/*
54 * the same as csum_partial, but copies from user space.
55 */
56
57unsigned int csum_partial_copy_fromuser(const char *src,
58					char *dst,
59					int len,
60					unsigned int sum,
61					int *src_err);
62
63unsigned int csum_partial_copy_nocheck(const char *src,
64				       char *dst,
65				       int len,
66				       unsigned int sum);
67
68/*
69 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
70 * 1's complement 16-bit checksum.
71 */
72static inline unsigned int csum_fold(unsigned int sum)
73{
74	unsigned int tmp;
75
76	/* swap the two 16-bit halves of sum */
77	__asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
78	/* if there is a carry from adding the two 16-bit halves,
79	   it will carry from the lower half into the upper half,
80	   giving us the correct sum in the upper half. */
81	sum = ~(sum + tmp) >> 16;
82	return sum;
83}
84
85/*
86 * this routine is used for miscellaneous IP-like checksums, mainly
87 * in icmp.c
88 */
89static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
90{
91	return csum_fold(csum_partial(buff, len, 0));
92}
93
94#define csum_partial_copy_from_user(src, dst, len, sum, errp)   \
95        csum_partial_copy_generic((src), (dst), (len), (sum), (errp), 0)
96
97#define csum_partial_copy_nocheck(src, dst, len, sum)   \
98        csum_partial_copy_generic((src), (dst), (len), (sum), 0, 0)
99
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
115#endif
116