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1 | /* |
2 | * Cryptographic API. |
3 | * |
4 | * CRC32C chksum |
5 | * |
6 | *@Article{castagnoli-crc, |
7 | * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman}, |
8 | * title = {{Optimization of Cyclic Redundancy-Check Codes with 24 |
9 | * and 32 Parity Bits}}, |
10 | * journal = IEEE Transactions on Communication, |
11 | * year = {1993}, |
12 | * volume = {41}, |
13 | * number = {6}, |
14 | * pages = {}, |
15 | * month = {June}, |
16 | *} |
17 | * Used by the iSCSI driver, possibly others, and derived from the |
18 | * the iscsi-crc.c module of the linux-iscsi driver at |
19 | * http://linux-iscsi.sourceforge.net. |
20 | * |
21 | * Following the example of lib/crc32, this function is intended to be |
22 | * flexible and useful for all users. Modules that currently have their |
23 | * own crc32c, but hopefully may be able to use this one are: |
24 | * net/sctp (please add all your doco to here if you change to |
25 | * use this one!) |
26 | * <endoflist> |
27 | * |
28 | * Copyright (c) 2004 Cisco Systems, Inc. |
29 | * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au> |
30 | * |
31 | * This program is free software; you can redistribute it and/or modify it |
32 | * under the terms of the GNU General Public License as published by the Free |
33 | * Software Foundation; either version 2 of the License, or (at your option) |
34 | * any later version. |
35 | * |
36 | */ |
37 | |
38 | #include <crypto/internal/hash.h> |
39 | #include <linux/init.h> |
40 | #include <linux/module.h> |
41 | #include <linux/string.h> |
42 | #include <linux/kernel.h> |
43 | |
44 | #define CHKSUM_BLOCK_SIZE 1 |
45 | #define CHKSUM_DIGEST_SIZE 4 |
46 | |
47 | struct chksum_ctx { |
48 | u32 key; |
49 | }; |
50 | |
51 | struct chksum_desc_ctx { |
52 | u32 crc; |
53 | }; |
54 | |
55 | /* |
56 | * This is the CRC-32C table |
57 | * Generated with: |
58 | * width = 32 bits |
59 | * poly = 0x1EDC6F41 |
60 | * reflect input bytes = true |
61 | * reflect output bytes = true |
62 | */ |
63 | |
64 | static const u32 crc32c_table[256] = { |
65 | 0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L, |
66 | 0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL, |
67 | 0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL, |
68 | 0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L, |
69 | 0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL, |
70 | 0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L, |
71 | 0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L, |
72 | 0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL, |
73 | 0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL, |
74 | 0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L, |
75 | 0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L, |
76 | 0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL, |
77 | 0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L, |
78 | 0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL, |
79 | 0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL, |
80 | 0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L, |
81 | 0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L, |
82 | 0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L, |
83 | 0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L, |
84 | 0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L, |
85 | 0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L, |
86 | 0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L, |
87 | 0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L, |
88 | 0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L, |
89 | 0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L, |
90 | 0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L, |
91 | 0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L, |
92 | 0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L, |
93 | 0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L, |
94 | 0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L, |
95 | 0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L, |
96 | 0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L, |
97 | 0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL, |
98 | 0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L, |
99 | 0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L, |
100 | 0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL, |
101 | 0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L, |
102 | 0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL, |
103 | 0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL, |
104 | 0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L, |
105 | 0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L, |
106 | 0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL, |
107 | 0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL, |
108 | 0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L, |
109 | 0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL, |
110 | 0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L, |
111 | 0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L, |
112 | 0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL, |
113 | 0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L, |
114 | 0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL, |
115 | 0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL, |
116 | 0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L, |
117 | 0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL, |
118 | 0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L, |
119 | 0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L, |
120 | 0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL, |
121 | 0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL, |
122 | 0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L, |
123 | 0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L, |
124 | 0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL, |
125 | 0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L, |
126 | 0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL, |
127 | 0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL, |
128 | 0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L |
129 | }; |
130 | |
131 | /* |
132 | * Steps through buffer one byte at at time, calculates reflected |
133 | * crc using table. |
134 | */ |
135 | |
136 | static u32 crc32c(u32 crc, const u8 *data, unsigned int length) |
137 | { |
138 | while (length--) |
139 | crc = crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8); |
140 | |
141 | return crc; |
142 | } |
143 | |
144 | /* |
145 | * Steps through buffer one byte at at time, calculates reflected |
146 | * crc using table. |
147 | */ |
148 | |
149 | static int chksum_init(struct shash_desc *desc) |
150 | { |
151 | struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm); |
152 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
153 | |
154 | ctx->crc = mctx->key; |
155 | |
156 | return 0; |
157 | } |
158 | |
159 | /* |
160 | * Setting the seed allows arbitrary accumulators and flexible XOR policy |
161 | * If your algorithm starts with ~0, then XOR with ~0 before you set |
162 | * the seed. |
163 | */ |
164 | static int chksum_setkey(struct crypto_shash *tfm, const u8 *key, |
165 | unsigned int keylen) |
166 | { |
167 | struct chksum_ctx *mctx = crypto_shash_ctx(tfm); |
168 | |
169 | if (keylen != sizeof(mctx->key)) { |
170 | crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); |
171 | return -EINVAL; |
172 | } |
173 | mctx->key = le32_to_cpu(*(__le32 *)key); |
174 | return 0; |
175 | } |
176 | |
177 | static int chksum_update(struct shash_desc *desc, const u8 *data, |
178 | unsigned int length) |
179 | { |
180 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
181 | |
182 | ctx->crc = crc32c(ctx->crc, data, length); |
183 | return 0; |
184 | } |
185 | |
186 | static int chksum_final(struct shash_desc *desc, u8 *out) |
187 | { |
188 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
189 | |
190 | *(__le32 *)out = ~cpu_to_le32p(&ctx->crc); |
191 | return 0; |
192 | } |
193 | |
194 | static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out) |
195 | { |
196 | *(__le32 *)out = ~cpu_to_le32(crc32c(*crcp, data, len)); |
197 | return 0; |
198 | } |
199 | |
200 | static int chksum_finup(struct shash_desc *desc, const u8 *data, |
201 | unsigned int len, u8 *out) |
202 | { |
203 | struct chksum_desc_ctx *ctx = shash_desc_ctx(desc); |
204 | |
205 | return __chksum_finup(&ctx->crc, data, len, out); |
206 | } |
207 | |
208 | static int chksum_digest(struct shash_desc *desc, const u8 *data, |
209 | unsigned int length, u8 *out) |
210 | { |
211 | struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm); |
212 | |
213 | return __chksum_finup(&mctx->key, data, length, out); |
214 | } |
215 | |
216 | static int crc32c_cra_init(struct crypto_tfm *tfm) |
217 | { |
218 | struct chksum_ctx *mctx = crypto_tfm_ctx(tfm); |
219 | |
220 | mctx->key = ~0; |
221 | return 0; |
222 | } |
223 | |
224 | static struct shash_alg alg = { |
225 | .digestsize = CHKSUM_DIGEST_SIZE, |
226 | .setkey = chksum_setkey, |
227 | .init = chksum_init, |
228 | .update = chksum_update, |
229 | .final = chksum_final, |
230 | .finup = chksum_finup, |
231 | .digest = chksum_digest, |
232 | .descsize = sizeof(struct chksum_desc_ctx), |
233 | .base = { |
234 | .cra_name = "crc32c", |
235 | .cra_driver_name = "crc32c-generic", |
236 | .cra_priority = 100, |
237 | .cra_blocksize = CHKSUM_BLOCK_SIZE, |
238 | .cra_alignmask = 3, |
239 | .cra_ctxsize = sizeof(struct chksum_ctx), |
240 | .cra_module = THIS_MODULE, |
241 | .cra_init = crc32c_cra_init, |
242 | } |
243 | }; |
244 | |
245 | static int __init crc32c_mod_init(void) |
246 | { |
247 | return crypto_register_shash(&alg); |
248 | } |
249 | |
250 | static void __exit crc32c_mod_fini(void) |
251 | { |
252 | crypto_unregister_shash(&alg); |
253 | } |
254 | |
255 | module_init(crc32c_mod_init); |
256 | module_exit(crc32c_mod_fini); |
257 | |
258 | MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>"); |
259 | MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c"); |
260 | MODULE_LICENSE("GPL"); |
261 |
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