| 1 | |
| 2 | |
| 3 | * Copyright 2012 Xyratex Technology Limited
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| 4 |
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| 5 |
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| 6 | |
| 7 | * This is crypto api shash wrappers to crc32_le.
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| 8 |
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| 9 |
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| 10 | #include <linux/unaligned.h>
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| 11 | #include <linux/crc32.h>
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| 12 | #include <crypto/internal/hash.h>
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| 13 | #include <linux/init.h>
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| 14 | #include <linux/module.h>
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| 15 | #include <linux/string.h>
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| 16 | #include <linux/kernel.h>
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| 17 |
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| 18 | #define CHKSUM_BLOCK_SIZE 1
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| 19 | #define CHKSUM_DIGEST_SIZE 4
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| 20 |
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| 21 |
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| 22 | static int crc32_cra_init(struct crypto_tfm *tfm)
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| 23 | {
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| 24 | u32 *key = crypto_tfm_ctx(tfm);
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| 25 |
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| 26 | *key = 0;
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| 27 |
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| 28 | return 0;
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| 29 | }
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| 30 |
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| 31 | |
| 32 | * Setting the seed allows arbitrary accumulators and flexible XOR policy
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| 33 | * If your algorithm starts with ~0, then XOR with ~0 before you set
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| 34 | * the seed.
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| 35 |
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| 36 | static int crc32_setkey(struct crypto_shash *hash, const u8 *key,
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| 37 | unsigned int keylen)
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| 38 | {
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| 39 | u32 *mctx = crypto_shash_ctx(hash);
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| 40 |
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| 41 | if (keylen != sizeof(u32))
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| 42 | return -EINVAL;
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| 43 | *mctx = get_unaligned_le32(key);
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| 44 | return 0;
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| 45 | }
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| 46 |
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| 47 | static int crc32_init(struct shash_desc *desc)
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| 48 | {
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| 49 | u32 *mctx = crypto_shash_ctx(desc->tfm);
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| 50 | u32 *crcp = shash_desc_ctx(desc);
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| 51 |
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| 52 | *crcp = *mctx;
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| 53 |
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| 54 | return 0;
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| 55 | }
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| 56 |
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| 57 | static int crc32_update(struct shash_desc *desc, const u8 *data,
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| 58 | unsigned int len)
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| 59 | {
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| 60 | u32 *crcp = shash_desc_ctx(desc);
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| 61 |
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| 62 | *crcp = crc32_le(*crcp, data, len);
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| 63 | return 0;
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| 64 | }
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| 65 |
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| 66 |
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| 67 | static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out)
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| 68 | {
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| 69 | put_unaligned_le32(crc32_le(*crcp, data, len), out);
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| 70 | return 0;
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| 71 | }
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| 72 |
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| 73 | static int crc32_finup(struct shash_desc *desc, const u8 *data,
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| 74 | unsigned int len, u8 *out)
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| 75 | {
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| 76 | return __crc32_finup(shash_desc_ctx(desc), data, len, out);
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| 77 | }
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| 78 |
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| 79 | static int crc32_final(struct shash_desc *desc, u8 *out)
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| 80 | {
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| 81 | u32 *crcp = shash_desc_ctx(desc);
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| 82 |
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| 83 | put_unaligned_le32(*crcp, out);
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| 84 | return 0;
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| 85 | }
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| 86 |
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| 87 | static int crc32_digest(struct shash_desc *desc, const u8 *data,
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| 88 | unsigned int len, u8 *out)
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| 89 | {
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| 90 | return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len, out);
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| 91 | }
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| 92 |
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| 93 | static struct shash_alg alg = {
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| 94 | .setkey = crc32_setkey,
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| 95 | .init = crc32_init,
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| 96 | .update = crc32_update,
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| 97 | .final = crc32_final,
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| 98 | .finup = crc32_finup,
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| 99 | .digest = crc32_digest,
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| 100 | .descsize = sizeof(u32),
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| 101 | .digestsize = CHKSUM_DIGEST_SIZE,
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| 102 |
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| 103 | .base.cra_name = "crc32",
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| 104 | .base.cra_driver_name = "crc32-lib",
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| 105 | .base.cra_priority = 100,
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| 106 | .base.cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
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| 107 | .base.cra_blocksize = CHKSUM_BLOCK_SIZE,
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| 108 | .base.cra_ctxsize = sizeof(u32),
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| 109 | .base.cra_module = THIS_MODULE,
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| 110 | .base.cra_init = crc32_cra_init,
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| 111 | };
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| 112 |
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| 113 | static int __init crc32_mod_init(void)
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| 114 | {
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| 115 | return crypto_register_shash(&alg);
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| 116 | }
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| 117 |
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| 118 | static void __exit crc32_mod_fini(void)
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| 119 | {
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| 120 | crypto_unregister_shash(&alg);
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| 121 | }
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| 122 |
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| 123 | module_init(crc32_mod_init);
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| 124 | module_exit(crc32_mod_fini);
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| 125 |
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| 126 | MODULE_AUTHOR("Alexander Boyko <[email protected]>");
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| 127 | MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32");
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| 128 | MODULE_LICENSE("GPL");
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| 129 | MODULE_ALIAS_CRYPTO("crc32");
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