xref: /openbmc/linux/lib/libcrc32c.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  * CRC32C
3  *@Article{castagnoli-crc,
4  * author =       { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
5  * title =        {{Optimization of Cyclic Redundancy-Check Codes with 24
6  *                 and 32 Parity Bits}},
7  * journal =      IEEE Transactions on Communication,
8  * year =         {1993},
9  * volume =       {41},
10  * number =       {6},
11  * pages =        {},
12  * month =        {June},
13  *}
14  * Used by the iSCSI driver, possibly others, and derived from the
15  * the iscsi-crc.c module of the linux-iscsi driver at
16  * http://linux-iscsi.sourceforge.net.
17  *
18  * Following the example of lib/crc32, this function is intended to be
19  * flexible and useful for all users.  Modules that currently have their
20  * own crc32c, but hopefully may be able to use this one are:
21  *  net/sctp (please add all your doco to here if you change to
22  *            use this one!)
23  *  <endoflist>
24  *
25  * Copyright (c) 2004 Cisco Systems, Inc.
26  *
27  * This program is free software; you can redistribute it and/or modify it
28  * under the terms of the GNU General Public License as published by the Free
29  * Software Foundation; either version 2 of the License, or (at your option)
30  * any later version.
31  *
32  */
33 #include <linux/crc32c.h>
34 #include <linux/compiler.h>
35 #include <linux/module.h>
36 #include <asm/byteorder.h>
37 
38 MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
39 MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
40 MODULE_LICENSE("GPL");
41 
42 #define CRC32C_POLY_BE 0x1EDC6F41
43 #define CRC32C_POLY_LE 0x82F63B78
44 
45 #ifndef CRC_LE_BITS
46 # define CRC_LE_BITS 8
47 #endif
48 
49 
50 /*
51  * Haven't generated a big-endian table yet, but the bit-wise version
52  * should at least work.
53  */
54 #if defined CRC_BE_BITS && CRC_BE_BITS != 1
55 #undef CRC_BE_BITS
56 #endif
57 #ifndef CRC_BE_BITS
58 # define CRC_BE_BITS 1
59 #endif
60 
61 EXPORT_SYMBOL(crc32c_le);
62 
63 #if CRC_LE_BITS == 1
64 /*
65  * Compute things bit-wise, as done in crc32.c.  We could share the tight
66  * loop below with crc32 and vary the POLY if we don't find value in terms
67  * of space and maintainability in keeping the two modules separate.
68  */
69 u32 __attribute_pure__
70 crc32c_le(u32 crc, unsigned char const *p, size_t len)
71 {
72 	int i;
73 	while (len--) {
74 		crc ^= *p++;
75 		for (i = 0; i < 8; i++)
76 			crc = (crc >> 1) ^ ((crc & 1) ? CRC32C_POLY_LE : 0);
77 	}
78 	return crc;
79 }
80 #else
81 
82 /*
83  * This is the CRC-32C table
84  * Generated with:
85  * width = 32 bits
86  * poly = 0x1EDC6F41
87  * reflect input bytes = true
88  * reflect output bytes = true
89  */
90 
91 static u32 crc32c_table[256] = {
92 	0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
93 	0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
94 	0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
95 	0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
96 	0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
97 	0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
98 	0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
99 	0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
100 	0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
101 	0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
102 	0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
103 	0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
104 	0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
105 	0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
106 	0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
107 	0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
108 	0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
109 	0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
110 	0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
111 	0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
112 	0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
113 	0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
114 	0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
115 	0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
116 	0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
117 	0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
118 	0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
119 	0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
120 	0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
121 	0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
122 	0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
123 	0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
124 	0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
125 	0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
126 	0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
127 	0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
128 	0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
129 	0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
130 	0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
131 	0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
132 	0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
133 	0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
134 	0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
135 	0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
136 	0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
137 	0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
138 	0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
139 	0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
140 	0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
141 	0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
142 	0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
143 	0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
144 	0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
145 	0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
146 	0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
147 	0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
148 	0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
149 	0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
150 	0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
151 	0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
152 	0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
153 	0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
154 	0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
155 	0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
156 };
157 
158 /*
159  * Steps through buffer one byte at at time, calculates reflected
160  * crc using table.
161  */
162 
163 u32 __attribute_pure__
164 crc32c_le(u32 seed, unsigned char const *data, size_t length)
165 {
166 	u32 crc = __cpu_to_le32(seed);
167 
168 	while (length--)
169 		crc =
170 		    crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);
171 
172 	return __le32_to_cpu(crc);
173 }
174 
175 #endif	/* CRC_LE_BITS == 8 */
176 
177 EXPORT_SYMBOL(crc32c_be);
178 
179 #if CRC_BE_BITS == 1
180 u32 __attribute_pure__
181 crc32c_be(u32 crc, unsigned char const *p, size_t len)
182 {
183 	int i;
184 	while (len--) {
185 		crc ^= *p++ << 24;
186 		for (i = 0; i < 8; i++)
187 			crc =
188 			    (crc << 1) ^ ((crc & 0x80000000) ? CRC32C_POLY_BE :
189 					  0);
190 	}
191 	return crc;
192 }
193 #endif
194 
195 /*
196  * Unit test
197  *
198  * A small unit test suite is implemented as part of the crypto suite.
199  * Select CRYPTO_CRC32C and use the tcrypt module to run the tests.
200  */
201