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
38MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
39MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
40MODULE_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
61EXPORT_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 */
69u32 __attribute_pure__
70crc32c_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
91static const 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
163u32 __attribute_pure__
164crc32c_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
177EXPORT_SYMBOL(crc32c_be);
178
179#if CRC_BE_BITS == 1
180u32 __attribute_pure__
181crc32c_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