diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-12 21:15:51 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-12 21:15:51 -0400 |
commit | cd166bd0dde265a97dd9aa8e3451a2646d96d04b (patch) | |
tree | 3a7fb5b8bb8d7676e804845b75977be380b8dcff /lib | |
parent | 6b702462cbe5b6f372966a53f4465d745d86b65c (diff) | |
parent | 5b02ee3d219f9e01b6e9146e25613822cfc2e5ce (diff) |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
add generic lib/checksum.c
asm-generic: add a generic uaccess.h
asm-generic: add generic NOMMU versions of some headers
asm-generic: add generic atomic.h and io.h
asm-generic: add legacy I/O header files
asm-generic: add generic versions of common headers
asm-generic: make bitops.h usable
asm-generic: make pci.h usable directly
asm-generic: make get_rtc_time overridable
asm-generic: rename page.h and uaccess.h
asm-generic: rename atomic.h to atomic-long.h
asm-generic: add a generic unistd.h
asm-generic: add generic ABI headers
asm-generic: add generic sysv ipc headers
asm-generic: introduce asm/bitsperlong.h
asm-generic: rename termios.h, signal.h and mman.h
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Makefile | 2 | ||||
-rw-r--r-- | lib/checksum.c | 193 |
2 files changed, 195 insertions, 0 deletions
diff --git a/lib/Makefile b/lib/Makefile index 1f6edefebffe..34c5c0e6222e 100644 --- a/lib/Makefile +++ b/lib/Makefile | |||
@@ -93,6 +93,8 @@ obj-$(CONFIG_NLATTR) += nlattr.o | |||
93 | 93 | ||
94 | obj-$(CONFIG_DMA_API_DEBUG) += dma-debug.o | 94 | obj-$(CONFIG_DMA_API_DEBUG) += dma-debug.o |
95 | 95 | ||
96 | obj-$(CONFIG_GENERIC_CSUM) += checksum.o | ||
97 | |||
96 | hostprogs-y := gen_crc32table | 98 | hostprogs-y := gen_crc32table |
97 | clean-files := crc32table.h | 99 | clean-files := crc32table.h |
98 | 100 | ||
diff --git a/lib/checksum.c b/lib/checksum.c new file mode 100644 index 000000000000..12e5a1c91cda --- /dev/null +++ b/lib/checksum.c | |||
@@ -0,0 +1,193 @@ | |||
1 | /* | ||
2 | * | ||
3 | * INET An implementation of the TCP/IP protocol suite for the LINUX | ||
4 | * operating system. INET is implemented using the BSD Socket | ||
5 | * interface as the means of communication with the user level. | ||
6 | * | ||
7 | * IP/TCP/UDP checksumming routines | ||
8 | * | ||
9 | * Authors: Jorge Cwik, <jorge@laser.satlink.net> | ||
10 | * Arnt Gulbrandsen, <agulbra@nvg.unit.no> | ||
11 | * Tom May, <ftom@netcom.com> | ||
12 | * Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de> | ||
13 | * Lots of code moved from tcp.c and ip.c; see those files | ||
14 | * for more names. | ||
15 | * | ||
16 | * 03/02/96 Jes Sorensen, Andreas Schwab, Roman Hodek: | ||
17 | * Fixed some nasty bugs, causing some horrible crashes. | ||
18 | * A: At some points, the sum (%0) was used as | ||
19 | * length-counter instead of the length counter | ||
20 | * (%1). Thanks to Roman Hodek for pointing this out. | ||
21 | * B: GCC seems to mess up if one uses too many | ||
22 | * data-registers to hold input values and one tries to | ||
23 | * specify d0 and d1 as scratch registers. Letting gcc | ||
24 | * choose these registers itself solves the problem. | ||
25 | * | ||
26 | * This program is free software; you can redistribute it and/or | ||
27 | * modify it under the terms of the GNU General Public License | ||
28 | * as published by the Free Software Foundation; either version | ||
29 | * 2 of the License, or (at your option) any later version. | ||
30 | */ | ||
31 | |||
32 | /* Revised by Kenneth Albanowski for m68knommu. Basic problem: unaligned access | ||
33 | kills, so most of the assembly has to go. */ | ||
34 | |||
35 | #include <linux/module.h> | ||
36 | #include <net/checksum.h> | ||
37 | |||
38 | #include <asm/byteorder.h> | ||
39 | |||
40 | static inline unsigned short from32to16(unsigned long x) | ||
41 | { | ||
42 | /* add up 16-bit and 16-bit for 16+c bit */ | ||
43 | x = (x & 0xffff) + (x >> 16); | ||
44 | /* add up carry.. */ | ||
45 | x = (x & 0xffff) + (x >> 16); | ||
46 | return x; | ||
47 | } | ||
48 | |||
49 | static unsigned int do_csum(const unsigned char *buff, int len) | ||
50 | { | ||
51 | int odd, count; | ||
52 | unsigned long result = 0; | ||
53 | |||
54 | if (len <= 0) | ||
55 | goto out; | ||
56 | odd = 1 & (unsigned long) buff; | ||
57 | if (odd) { | ||
58 | result = *buff; | ||
59 | len--; | ||
60 | buff++; | ||
61 | } | ||
62 | count = len >> 1; /* nr of 16-bit words.. */ | ||
63 | if (count) { | ||
64 | if (2 & (unsigned long) buff) { | ||
65 | result += *(unsigned short *) buff; | ||
66 | count--; | ||
67 | len -= 2; | ||
68 | buff += 2; | ||
69 | } | ||
70 | count >>= 1; /* nr of 32-bit words.. */ | ||
71 | if (count) { | ||
72 | unsigned long carry = 0; | ||
73 | do { | ||
74 | unsigned long w = *(unsigned long *) buff; | ||
75 | count--; | ||
76 | buff += 4; | ||
77 | result += carry; | ||
78 | result += w; | ||
79 | carry = (w > result); | ||
80 | } while (count); | ||
81 | result += carry; | ||
82 | result = (result & 0xffff) + (result >> 16); | ||
83 | } | ||
84 | if (len & 2) { | ||
85 | result += *(unsigned short *) buff; | ||
86 | buff += 2; | ||
87 | } | ||
88 | } | ||
89 | if (len & 1) | ||
90 | result += (*buff << 8); | ||
91 | result = from32to16(result); | ||
92 | if (odd) | ||
93 | result = ((result >> 8) & 0xff) | ((result & 0xff) << 8); | ||
94 | out: | ||
95 | return result; | ||
96 | } | ||
97 | |||
98 | /* | ||
99 | * This is a version of ip_compute_csum() optimized for IP headers, | ||
100 | * which always checksum on 4 octet boundaries. | ||
101 | */ | ||
102 | __sum16 ip_fast_csum(const void *iph, unsigned int ihl) | ||
103 | { | ||
104 | return (__force __sum16)~do_csum(iph, ihl*4); | ||
105 | } | ||
106 | EXPORT_SYMBOL(ip_fast_csum); | ||
107 | |||
108 | /* | ||
109 | * computes the checksum of a memory block at buff, length len, | ||
110 | * and adds in "sum" (32-bit) | ||
111 | * | ||
112 | * returns a 32-bit number suitable for feeding into itself | ||
113 | * or csum_tcpudp_magic | ||
114 | * | ||
115 | * this function must be called with even lengths, except | ||
116 | * for the last fragment, which may be odd | ||
117 | * | ||
118 | * it's best to have buff aligned on a 32-bit boundary | ||
119 | */ | ||
120 | __wsum csum_partial(const void *buff, int len, __wsum wsum) | ||
121 | { | ||
122 | unsigned int sum = (__force unsigned int)wsum; | ||
123 | unsigned int result = do_csum(buff, len); | ||
124 | |||
125 | /* add in old sum, and carry.. */ | ||
126 | result += sum; | ||
127 | if (sum > result) | ||
128 | result += 1; | ||
129 | return (__force __wsum)result; | ||
130 | } | ||
131 | EXPORT_SYMBOL(csum_partial); | ||
132 | |||
133 | /* | ||
134 | * this routine is used for miscellaneous IP-like checksums, mainly | ||
135 | * in icmp.c | ||
136 | */ | ||
137 | __sum16 ip_compute_csum(const void *buff, int len) | ||
138 | { | ||
139 | return (__force __sum16)~do_csum(buff, len); | ||
140 | } | ||
141 | EXPORT_SYMBOL(ip_compute_csum); | ||
142 | |||
143 | /* | ||
144 | * copy from fs while checksumming, otherwise like csum_partial | ||
145 | */ | ||
146 | __wsum | ||
147 | csum_partial_copy_from_user(const void __user *src, void *dst, int len, | ||
148 | __wsum sum, int *csum_err) | ||
149 | { | ||
150 | int missing; | ||
151 | |||
152 | missing = __copy_from_user(dst, src, len); | ||
153 | if (missing) { | ||
154 | memset(dst + len - missing, 0, missing); | ||
155 | *csum_err = -EFAULT; | ||
156 | } else | ||
157 | *csum_err = 0; | ||
158 | |||
159 | return csum_partial(dst, len, sum); | ||
160 | } | ||
161 | EXPORT_SYMBOL(csum_partial_copy_from_user); | ||
162 | |||
163 | /* | ||
164 | * copy from ds while checksumming, otherwise like csum_partial | ||
165 | */ | ||
166 | __wsum | ||
167 | csum_partial_copy(const void *src, void *dst, int len, __wsum sum) | ||
168 | { | ||
169 | memcpy(dst, src, len); | ||
170 | return csum_partial(dst, len, sum); | ||
171 | } | ||
172 | EXPORT_SYMBOL(csum_partial_copy); | ||
173 | |||
174 | #ifndef csum_tcpudp_nofold | ||
175 | __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, | ||
176 | unsigned short len, | ||
177 | unsigned short proto, | ||
178 | __wsum sum) | ||
179 | { | ||
180 | unsigned long long s = (__force u32)sum; | ||
181 | |||
182 | s += (__force u32)saddr; | ||
183 | s += (__force u32)daddr; | ||
184 | #ifdef __BIG_ENDIAN | ||
185 | s += proto + len; | ||
186 | #else | ||
187 | s += (proto + len) << 8; | ||
188 | #endif | ||
189 | s += (s >> 32); | ||
190 | return (__force __wsum)s; | ||
191 | } | ||
192 | EXPORT_SYMBOL(csum_tcpudp_nofold); | ||
193 | #endif | ||