diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/m68knommu/lib/checksum.c |
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/m68knommu/lib/checksum.c')
-rw-r--r-- | arch/m68knommu/lib/checksum.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/arch/m68knommu/lib/checksum.c b/arch/m68knommu/lib/checksum.c new file mode 100644 index 000000000000..7bec6fdee34b --- /dev/null +++ b/arch/m68knommu/lib/checksum.c | |||
@@ -0,0 +1,160 @@ | |||
1 | /* | ||
2 | * INET An implementation of the TCP/IP protocol suite for the LINUX | ||
3 | * operating system. INET is implemented using the BSD Socket | ||
4 | * interface as the means of communication with the user level. | ||
5 | * | ||
6 | * IP/TCP/UDP checksumming routines | ||
7 | * | ||
8 | * Authors: Jorge Cwik, <jorge@laser.satlink.net> | ||
9 | * Arnt Gulbrandsen, <agulbra@nvg.unit.no> | ||
10 | * Tom May, <ftom@netcom.com> | ||
11 | * Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de> | ||
12 | * Lots of code moved from tcp.c and ip.c; see those files | ||
13 | * for more names. | ||
14 | * | ||
15 | * 03/02/96 Jes Sorensen, Andreas Schwab, Roman Hodek: | ||
16 | * Fixed some nasty bugs, causing some horrible crashes. | ||
17 | * A: At some points, the sum (%0) was used as | ||
18 | * length-counter instead of the length counter | ||
19 | * (%1). Thanks to Roman Hodek for pointing this out. | ||
20 | * B: GCC seems to mess up if one uses too many | ||
21 | * data-registers to hold input values and one tries to | ||
22 | * specify d0 and d1 as scratch registers. Letting gcc choose these | ||
23 | * registers itself solves the problem. | ||
24 | * | ||
25 | * This program is free software; you can redistribute it and/or | ||
26 | * modify it under the terms of the GNU General Public License | ||
27 | * as published by the Free Software Foundation; either version | ||
28 | * 2 of the License, or (at your option) any later version. | ||
29 | */ | ||
30 | |||
31 | /* Revised by Kenneth Albanowski for m68knommu. Basic problem: unaligned access kills, so most | ||
32 | of the assembly has to go. */ | ||
33 | |||
34 | #include <linux/module.h> | ||
35 | #include <net/checksum.h> | ||
36 | |||
37 | static inline unsigned short from32to16(unsigned long x) | ||
38 | { | ||
39 | /* add up 16-bit and 16-bit for 16+c bit */ | ||
40 | x = (x & 0xffff) + (x >> 16); | ||
41 | /* add up carry.. */ | ||
42 | x = (x & 0xffff) + (x >> 16); | ||
43 | return x; | ||
44 | } | ||
45 | |||
46 | static unsigned long do_csum(const unsigned char * buff, int len) | ||
47 | { | ||
48 | int odd, count; | ||
49 | unsigned long result = 0; | ||
50 | |||
51 | if (len <= 0) | ||
52 | goto out; | ||
53 | odd = 1 & (unsigned long) buff; | ||
54 | if (odd) { | ||
55 | result = *buff; | ||
56 | len--; | ||
57 | buff++; | ||
58 | } | ||
59 | count = len >> 1; /* nr of 16-bit words.. */ | ||
60 | if (count) { | ||
61 | if (2 & (unsigned long) buff) { | ||
62 | result += *(unsigned short *) buff; | ||
63 | count--; | ||
64 | len -= 2; | ||
65 | buff += 2; | ||
66 | } | ||
67 | count >>= 1; /* nr of 32-bit words.. */ | ||
68 | if (count) { | ||
69 | unsigned long carry = 0; | ||
70 | do { | ||
71 | unsigned long w = *(unsigned long *) buff; | ||
72 | count--; | ||
73 | buff += 4; | ||
74 | result += carry; | ||
75 | result += w; | ||
76 | carry = (w > result); | ||
77 | } while (count); | ||
78 | result += carry; | ||
79 | result = (result & 0xffff) + (result >> 16); | ||
80 | } | ||
81 | if (len & 2) { | ||
82 | result += *(unsigned short *) buff; | ||
83 | buff += 2; | ||
84 | } | ||
85 | } | ||
86 | if (len & 1) | ||
87 | result += (*buff << 8); | ||
88 | result = from32to16(result); | ||
89 | if (odd) | ||
90 | result = ((result >> 8) & 0xff) | ((result & 0xff) << 8); | ||
91 | out: | ||
92 | return result; | ||
93 | } | ||
94 | |||
95 | /* | ||
96 | * This is a version of ip_compute_csum() optimized for IP headers, | ||
97 | * which always checksum on 4 octet boundaries. | ||
98 | */ | ||
99 | unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl) | ||
100 | { | ||
101 | return ~do_csum(iph,ihl*4); | ||
102 | } | ||
103 | |||
104 | /* | ||
105 | * computes the checksum of a memory block at buff, length len, | ||
106 | * and adds in "sum" (32-bit) | ||
107 | * | ||
108 | * returns a 32-bit number suitable for feeding into itself | ||
109 | * or csum_tcpudp_magic | ||
110 | * | ||
111 | * this function must be called with even lengths, except | ||
112 | * for the last fragment, which may be odd | ||
113 | * | ||
114 | * it's best to have buff aligned on a 32-bit boundary | ||
115 | */ | ||
116 | unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum) | ||
117 | { | ||
118 | unsigned int result = do_csum(buff, len); | ||
119 | |||
120 | /* add in old sum, and carry.. */ | ||
121 | result += sum; | ||
122 | if (sum > result) | ||
123 | result += 1; | ||
124 | return result; | ||
125 | } | ||
126 | |||
127 | EXPORT_SYMBOL(csum_partial); | ||
128 | |||
129 | /* | ||
130 | * this routine is used for miscellaneous IP-like checksums, mainly | ||
131 | * in icmp.c | ||
132 | */ | ||
133 | unsigned short ip_compute_csum(const unsigned char * buff, int len) | ||
134 | { | ||
135 | return ~do_csum(buff,len); | ||
136 | } | ||
137 | |||
138 | /* | ||
139 | * copy from fs while checksumming, otherwise like csum_partial | ||
140 | */ | ||
141 | |||
142 | unsigned int | ||
143 | csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst, | ||
144 | int len, int sum, int *csum_err) | ||
145 | { | ||
146 | if (csum_err) *csum_err = 0; | ||
147 | memcpy(dst, src, len); | ||
148 | return csum_partial(dst, len, sum); | ||
149 | } | ||
150 | |||
151 | /* | ||
152 | * copy from ds while checksumming, otherwise like csum_partial | ||
153 | */ | ||
154 | |||
155 | unsigned int | ||
156 | csum_partial_copy(const unsigned char *src, unsigned char *dst, int len, int sum) | ||
157 | { | ||
158 | memcpy(dst, src, len); | ||
159 | return csum_partial(dst, len, sum); | ||
160 | } | ||