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69c35efcf1
This patch swaps the role of libcrc32c and crc32c. Previously the implementation was in libcrc32c and crc32c was a wrapper. Now the code is in crc32c and libcrc32c just calls the crypto layer. The reason for the change is to tap into the algorithm selection capability of the crypto API so that optimised implementations such as the one utilising Intel's CRC32C instruction can be used where available. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
79 lines
2.1 KiB
C
79 lines
2.1 KiB
C
/*
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* CRC32C
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*@Article{castagnoli-crc,
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* author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
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* title = {{Optimization of Cyclic Redundancy-Check Codes with 24
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* and 32 Parity Bits}},
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* journal = IEEE Transactions on Communication,
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* year = {1993},
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* volume = {41},
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* number = {6},
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* pages = {},
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* month = {June},
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*}
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* Used by the iSCSI driver, possibly others, and derived from the
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* the iscsi-crc.c module of the linux-iscsi driver at
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* http://linux-iscsi.sourceforge.net.
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*
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* Following the example of lib/crc32, this function is intended to be
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* flexible and useful for all users. Modules that currently have their
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* own crc32c, but hopefully may be able to use this one are:
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* net/sctp (please add all your doco to here if you change to
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* use this one!)
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* <endoflist>
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*
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* Copyright (c) 2004 Cisco Systems, Inc.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <crypto/hash.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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static struct crypto_shash *tfm;
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u32 crc32c(u32 crc, const void *address, unsigned int length)
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{
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struct {
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struct shash_desc shash;
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char ctx[crypto_shash_descsize(tfm)];
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} desc;
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int err;
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desc.shash.tfm = tfm;
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desc.shash.flags = 0;
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*(u32 *)desc.ctx = crc;
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err = crypto_shash_update(&desc.shash, address, length);
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BUG_ON(err);
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return *(u32 *)desc.ctx;
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}
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static int __init libcrc32c_mod_init(void)
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{
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tfm = crypto_alloc_shash("crc32c", 0, 0);
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if (IS_ERR(tfm))
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return PTR_ERR(tfm);
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return 0;
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}
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static void __exit libcrc32c_mod_fini(void)
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{
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crypto_free_shash(tfm);
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}
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module_init(libcrc32c_mod_init);
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module_exit(libcrc32c_mod_fini);
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MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
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MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
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MODULE_LICENSE("GPL");
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