| 1 | |
| 2 | |
| 3 | * CRC32C
|
| 4 | *@Article{castagnoli-crc,
|
| 5 | * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
|
| 6 | * title = {{Optimization of Cyclic Redundancy-Check Codes with 24
|
| 7 | * and 32 Parity Bits}},
|
| 8 | * journal = IEEE Transactions on Communication,
|
| 9 | * year = {1993},
|
| 10 | * volume = {41},
|
| 11 | * number = {6},
|
| 12 | * pages = {},
|
| 13 | * month = {June},
|
| 14 | *}
|
| 15 | * Used by the iSCSI driver, possibly others, and derived from
|
| 16 | * the iscsi-crc.c module of the linux-iscsi driver at
|
| 17 | * http://linux-iscsi.sourceforge.net.
|
| 18 | *
|
| 19 | * Following the example of lib/crc32, this function is intended to be
|
| 20 | * flexible and useful for all users. Modules that currently have their
|
| 21 | * own crc32c, but hopefully may be able to use this one are:
|
| 22 | * net/sctp (please add all your doco to here if you change to
|
| 23 | * use this one!)
|
| 24 | * <endoflist>
|
| 25 | *
|
| 26 | * Copyright (c) 2004 Cisco Systems, Inc.
|
| 27 |
|
| 28 |
|
| 29 | #include <crypto/hash.h>
|
| 30 | #include <linux/err.h>
|
| 31 | #include <linux/init.h>
|
| 32 | #include <linux/kernel.h>
|
| 33 | #include <linux/module.h>
|
| 34 | #include <linux/crc32c.h>
|
| 35 |
|
| 36 | static struct crypto_shash *tfm;
|
| 37 |
|
| 38 | u32 crc32c(u32 crc, const void *address, unsigned int length)
|
| 39 | {
|
| 40 | SHASH_DESC_ON_STACK(shash, tfm);
|
| 41 | u32 ret, *ctx = (u32 *)shash_desc_ctx(shash);
|
| 42 | int err;
|
| 43 |
|
| 44 | shash->tfm = tfm;
|
| 45 | *ctx = crc;
|
| 46 |
|
| 47 | err = crypto_shash_update(shash, address, length);
|
| 48 | BUG_ON(err);
|
| 49 |
|
| 50 | ret = *ctx;
|
| 51 | barrier_data(ctx);
|
| 52 | return ret;
|
| 53 | }
|
| 54 |
|
| 55 | EXPORT_SYMBOL(crc32c);
|
| 56 |
|
| 57 | static int __init libcrc32c_mod_init(void)
|
| 58 | {
|
| 59 | tfm = crypto_alloc_shash("crc32c", 0, 0);
|
| 60 | return PTR_ERR_OR_ZERO(tfm);
|
| 61 | }
|
| 62 |
|
| 63 | static void __exit libcrc32c_mod_fini(void)
|
| 64 | {
|
| 65 | crypto_free_shash(tfm);
|
| 66 | }
|
| 67 |
|
| 68 | const char *crc32c_impl(void)
|
| 69 | {
|
| 70 | return crypto_shash_driver_name(tfm);
|
| 71 | }
|
| 72 | EXPORT_SYMBOL(crc32c_impl);
|
| 73 |
|
| 74 | module_init(libcrc32c_mod_init);
|
| 75 | module_exit(libcrc32c_mod_fini);
|
| 76 |
|
| 77 | MODULE_AUTHOR("Clay Haapala <[email protected]>");
|
| 78 | MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
|
| 79 | MODULE_LICENSE("GPL");
|
| 80 | MODULE_SOFTDEP("pre: crc32c");
|