| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
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| 2 | /* |
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| 3 | * CRC32C |
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| 4 | *@Article{castagnoli-crc, |
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| 5 | * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman}, |
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| 6 | * title = {{Optimization of Cyclic Redundancy-Check Codes with 24 |
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| 7 | * and 32 Parity Bits}}, |
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| 8 | * journal = IEEE Transactions on Communication, |
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| 9 | * year = {1993}, |
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| 10 | * volume = {41}, |
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| 11 | * number = {6}, |
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| 12 | * pages = {}, |
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| 13 | * month = {June}, |
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| 14 | *} |
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| 15 | * Used by the iSCSI driver, possibly others, and derived from |
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| 16 | * the iscsi-crc.c module of the linux-iscsi driver at |
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| 17 | * http://linux-iscsi.sourceforge.net. |
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| 18 | * |
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| 19 | * Following the example of lib/crc32, this function is intended to be |
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| 20 | * flexible and useful for all users. Modules that currently have their |
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| 21 | * own crc32c, but hopefully may be able to use this one are: |
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| 22 | * net/sctp (please add all your doco to here if you change to |
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| 23 | * use this one!) |
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| 24 | * <endoflist> |
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| 25 | * |
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| 26 | * Copyright (c) 2004 Cisco Systems, Inc. |
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| 27 | */ |
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| 28 | |
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| 29 | #include <crypto/hash.h> |
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| 30 | #include <linux/err.h> |
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| 31 | #include <linux/init.h> |
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| 32 | #include <linux/kernel.h> |
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| 33 | #include <linux/module.h> |
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| 34 | #include <linux/crc32c.h> |
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| 35 | |
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| 36 | static struct crypto_shash *tfm; |
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| 37 | |
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| 38 | u32 crc32c(u32 crc, const void *address, unsigned int length) |
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| 39 | { |
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| 40 | SHASH_DESC_ON_STACK(shash, tfm); |
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| 41 | u32 ret, *ctx = (u32 *)shash_desc_ctx(desc: shash); |
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| 42 | int err; |
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| 43 | |
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| 44 | shash->tfm = tfm; |
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| 45 | *ctx = crc; |
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| 46 | |
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| 47 | err = crypto_shash_update(desc: shash, data: address, len: length); |
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| 48 | BUG_ON(err); |
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| 49 | |
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| 50 | ret = *ctx; |
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| 51 | barrier_data(ctx); |
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| 52 | return ret; |
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| 53 | } |
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| 54 | |
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| 55 | EXPORT_SYMBOL(crc32c); |
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| 56 | |
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| 57 | static int __init libcrc32c_mod_init(void) |
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| 58 | { |
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| 59 | tfm = crypto_alloc_shash(alg_name: "crc32c" , type: 0, mask: 0); |
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| 60 | return PTR_ERR_OR_ZERO(ptr: tfm); |
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| 61 | } |
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| 62 | |
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| 63 | static void __exit libcrc32c_mod_fini(void) |
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| 64 | { |
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| 65 | crypto_free_shash(tfm); |
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| 66 | } |
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| 67 | |
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| 68 | module_init(libcrc32c_mod_init); |
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| 69 | module_exit(libcrc32c_mod_fini); |
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| 70 | |
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| 71 | MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>" ); |
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| 72 | MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations" ); |
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| 73 | MODULE_LICENSE("GPL" ); |
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| 74 | MODULE_SOFTDEP("pre: crc32c" ); |
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| 75 | |
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