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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/um/include/sysdep-x86_64/checksum.h
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/um/include/sysdep-x86_64/checksum.h')
-rw-r--r--arch/um/include/sysdep-x86_64/checksum.h151
1 files changed, 151 insertions, 0 deletions
diff --git a/arch/um/include/sysdep-x86_64/checksum.h b/arch/um/include/sysdep-x86_64/checksum.h
new file mode 100644
index 000000000000..572c6c19be33
--- /dev/null
+++ b/arch/um/include/sysdep-x86_64/checksum.h
@@ -0,0 +1,151 @@
1/*
2 * Licensed under the GPL
3 */
4
5#ifndef __UM_SYSDEP_CHECKSUM_H
6#define __UM_SYSDEP_CHECKSUM_H
7
8#include "linux/string.h"
9#include "linux/in6.h"
10#include "asm/uaccess.h"
11
12extern unsigned int csum_partial_copy_from(const unsigned char *src, unsigned char *dst, int len,
13 int sum, int *err_ptr);
14extern unsigned csum_partial(const unsigned char *buff, unsigned len,
15 unsigned sum);
16
17/*
18 * Note: when you get a NULL pointer exception here this means someone
19 * passed in an incorrect kernel address to one of these functions.
20 *
21 * If you use these functions directly please don't forget the
22 * access_ok().
23 */
24
25static __inline__
26unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst,
27 int len, int sum)
28{
29 memcpy(dst, src, len);
30 return(csum_partial(dst, len, sum));
31}
32
33static __inline__
34unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst,
35 int len, int sum, int *err_ptr)
36{
37 return csum_partial_copy_from(src, dst, len, sum, err_ptr);
38}
39
40/**
41 * csum_fold - Fold and invert a 32bit checksum.
42 * sum: 32bit unfolded sum
43 *
44 * Fold a 32bit running checksum to 16bit and invert it. This is usually
45 * the last step before putting a checksum into a packet.
46 * Make sure not to mix with 64bit checksums.
47 */
48static inline unsigned int csum_fold(unsigned int sum)
49{
50 __asm__(
51 " addl %1,%0\n"
52 " adcl $0xffff,%0"
53 : "=r" (sum)
54 : "r" (sum << 16), "0" (sum & 0xffff0000)
55 );
56 return (~sum) >> 16;
57}
58
59/**
60 * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
61 * @saddr: source address
62 * @daddr: destination address
63 * @len: length of packet
64 * @proto: ip protocol of packet
65 * @sum: initial sum to be added in (32bit unfolded)
66 *
67 * Returns the pseudo header checksum the input data. Result is
68 * 32bit unfolded.
69 */
70static inline unsigned long
71csum_tcpudp_nofold(unsigned saddr, unsigned daddr, unsigned short len,
72 unsigned short proto, unsigned int sum)
73{
74 asm(" addl %1, %0\n"
75 " adcl %2, %0\n"
76 " adcl %3, %0\n"
77 " adcl $0, %0\n"
78 : "=r" (sum)
79 : "g" (daddr), "g" (saddr), "g" ((ntohs(len)<<16)+proto*256), "0" (sum));
80 return sum;
81}
82
83/*
84 * computes the checksum of the TCP/UDP pseudo-header
85 * returns a 16-bit checksum, already complemented
86 */
87static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
88 unsigned long daddr,
89 unsigned short len,
90 unsigned short proto,
91 unsigned int sum)
92{
93 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
94}
95
96/**
97 * ip_fast_csum - Compute the IPv4 header checksum efficiently.
98 * iph: ipv4 header
99 * ihl: length of header / 4
100 */
101static inline unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl)
102{
103 unsigned int sum;
104
105 asm( " movl (%1), %0\n"
106 " subl $4, %2\n"
107 " jbe 2f\n"
108 " addl 4(%1), %0\n"
109 " adcl 8(%1), %0\n"
110 " adcl 12(%1), %0\n"
111 "1: adcl 16(%1), %0\n"
112 " lea 4(%1), %1\n"
113 " decl %2\n"
114 " jne 1b\n"
115 " adcl $0, %0\n"
116 " movl %0, %2\n"
117 " shrl $16, %0\n"
118 " addw %w2, %w0\n"
119 " adcl $0, %0\n"
120 " notl %0\n"
121 "2:"
122 /* Since the input registers which are loaded with iph and ipl
123 are modified, we must also specify them as outputs, or gcc
124 will assume they contain their original values. */
125 : "=r" (sum), "=r" (iph), "=r" (ihl)
126 : "1" (iph), "2" (ihl)
127 : "memory");
128 return(sum);
129}
130
131static inline unsigned add32_with_carry(unsigned a, unsigned b)
132{
133 asm("addl %2,%0\n\t"
134 "adcl $0,%0"
135 : "=r" (a)
136 : "0" (a), "r" (b));
137 return a;
138}
139
140#endif
141
142/*
143 * Overrides for Emacs so that we follow Linus's tabbing style.
144 * Emacs will notice this stuff at the end of the file and automatically
145 * adjust the settings for this buffer only. This must remain at the end
146 * of the file.
147 * ---------------------------------------------------------------------------
148 * Local variables:
149 * c-file-style: "linux"
150 * End:
151 */