Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / crypto / crc32c_generic.c

diff --git a/kernel/crypto/crc32c_generic.c b/kernel/crypto/crc32c_generic.c
new file mode 100644 (file)
index 0000000..06f1b60
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+++ b/kernel/crypto/crc32c_generic.c
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+/*
+ * Cryptographic API.
+ *
+ * CRC32C chksum
+ *
+ *@Article{castagnoli-crc,
+ * author =       { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
+ * title =        {{Optimization of Cyclic Redundancy-Check Codes with 24
+ *                 and 32 Parity Bits}},
+ * journal =      IEEE Transactions on Communication,
+ * year =         {1993},
+ * volume =       {41},
+ * number =       {6},
+ * pages =        {},
+ * month =        {June},
+ *}
+ * Used by the iSCSI driver, possibly others, and derived from the
+ * the iscsi-crc.c module of the linux-iscsi driver at
+ * http://linux-iscsi.sourceforge.net.
+ *
+ * Following the example of lib/crc32, this function is intended to be
+ * flexible and useful for all users.  Modules that currently have their
+ * own crc32c, but hopefully may be able to use this one are:
+ *  net/sctp (please add all your doco to here if you change to
+ *            use this one!)
+ *  <endoflist>
+ *
+ * Copyright (c) 2004 Cisco Systems, Inc.
+ * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#include <crypto/internal/hash.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/crc32.h>
+
+#define CHKSUM_BLOCK_SIZE      1
+#define CHKSUM_DIGEST_SIZE     4
+
+struct chksum_ctx {
+       u32 key;
+};
+
+struct chksum_desc_ctx {
+       u32 crc;
+};
+
+/*
+ * Steps through buffer one byte at at time, calculates reflected
+ * crc using table.
+ */
+
+static int chksum_init(struct shash_desc *desc)
+{
+       struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
+       struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+       ctx->crc = mctx->key;
+
+       return 0;
+}
+
+/*
+ * Setting the seed allows arbitrary accumulators and flexible XOR policy
+ * If your algorithm starts with ~0, then XOR with ~0 before you set
+ * the seed.
+ */
+static int chksum_setkey(struct crypto_shash *tfm, const u8 *key,
+                        unsigned int keylen)
+{
+       struct chksum_ctx *mctx = crypto_shash_ctx(tfm);
+
+       if (keylen != sizeof(mctx->key)) {
+               crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+               return -EINVAL;
+       }
+       mctx->key = le32_to_cpu(*(__le32 *)key);
+       return 0;
+}
+
+static int chksum_update(struct shash_desc *desc, const u8 *data,
+                        unsigned int length)
+{
+       struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+       ctx->crc = __crc32c_le(ctx->crc, data, length);
+       return 0;
+}
+
+static int chksum_final(struct shash_desc *desc, u8 *out)
+{
+       struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+       *(__le32 *)out = ~cpu_to_le32p(&ctx->crc);
+       return 0;
+}
+
+static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out)
+{
+       *(__le32 *)out = ~cpu_to_le32(__crc32c_le(*crcp, data, len));
+       return 0;
+}
+
+static int chksum_finup(struct shash_desc *desc, const u8 *data,
+                       unsigned int len, u8 *out)
+{
+       struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
+
+       return __chksum_finup(&ctx->crc, data, len, out);
+}
+
+static int chksum_digest(struct shash_desc *desc, const u8 *data,
+                        unsigned int length, u8 *out)
+{
+       struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
+
+       return __chksum_finup(&mctx->key, data, length, out);
+}
+
+static int crc32c_cra_init(struct crypto_tfm *tfm)
+{
+       struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
+
+       mctx->key = ~0;
+       return 0;
+}
+
+static struct shash_alg alg = {
+       .digestsize             =       CHKSUM_DIGEST_SIZE,
+       .setkey                 =       chksum_setkey,
+       .init           =       chksum_init,
+       .update         =       chksum_update,
+       .final          =       chksum_final,
+       .finup          =       chksum_finup,
+       .digest         =       chksum_digest,
+       .descsize               =       sizeof(struct chksum_desc_ctx),
+       .base                   =       {
+               .cra_name               =       "crc32c",
+               .cra_driver_name        =       "crc32c-generic",
+               .cra_priority           =       100,
+               .cra_blocksize          =       CHKSUM_BLOCK_SIZE,
+               .cra_alignmask          =       3,
+               .cra_ctxsize            =       sizeof(struct chksum_ctx),
+               .cra_module             =       THIS_MODULE,
+               .cra_init               =       crc32c_cra_init,
+       }
+};
+
+static int __init crc32c_mod_init(void)
+{
+       return crypto_register_shash(&alg);
+}
+
+static void __exit crc32c_mod_fini(void)
+{
+       crypto_unregister_shash(&alg);
+}
+
+module_init(crc32c_mod_init);
+module_exit(crc32c_mod_fini);
+
+MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
+MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_CRYPTO("crc32c");
+MODULE_ALIAS_CRYPTO("crc32c-generic");
+MODULE_SOFTDEP("pre: crc32c");