1 files changed, 110 insertions, 0 deletions
diff --git a/crypto/crc32c.c b/crypto/crc32c.c
new file mode 100644
index 0000000..256956c
--- /dev/null
+++ b/crypto/crc32c.c
@@ -0,0 +1,110 @@
+/* 
+ * Cryptographic API.
+ *
+ * CRC32C chksum
+ *
+ * This module file is a wrapper to invoke the lib/crc32c routines.
+ *
+ * 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 <linux/init.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/crypto.h>
+#include <linux/crc32c.h>
+#include <asm/byteorder.h>
+
+#define CHKSUM_BLOCK_SIZE	32
+#define CHKSUM_DIGEST_SIZE	4
+
+struct chksum_ctx {
+	u32 crc;
+};
+
+/*
+ * Steps through buffer one byte at at time, calculates reflected 
+ * crc using table.
+ */
+
+static void chksum_init(void *ctx)
+{
+	struct chksum_ctx *mctx = ctx;
+
+	mctx->crc = ~(u32)0;			/* common usage */
+}
+
+/*
+ * 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(void *ctx, const u8 *key, unsigned int keylen,
+	                  u32 *flags)
+{
+	struct chksum_ctx *mctx = ctx;
+
+	if (keylen != sizeof(mctx->crc)) {
+		if (flags)
+			*flags = CRYPTO_TFM_RES_BAD_KEY_LEN;
+		return -EINVAL;
+	}
+	mctx->crc = __cpu_to_le32(*(u32 *)key);
+	return 0;
+}
+
+static void chksum_update(void *ctx, const u8 *data, unsigned int length)
+{
+	struct chksum_ctx *mctx = ctx;
+	u32 mcrc;
+
+	mcrc = crc32c(mctx->crc, data, (size_t)length);
+
+	mctx->crc = mcrc;
+}
+
+static void chksum_final(void *ctx, u8 *out)
+{
+	struct chksum_ctx *mctx = ctx;
+	u32 mcrc = (mctx->crc ^ ~(u32)0);
+	
+	*(u32 *)out = __le32_to_cpu(mcrc);
+}
+
+static struct crypto_alg alg = {
+	.cra_name	=	"crc32c",
+	.cra_flags	=	CRYPTO_ALG_TYPE_DIGEST,
+	.cra_blocksize	=	CHKSUM_BLOCK_SIZE,
+	.cra_ctxsize	=	sizeof(struct chksum_ctx),
+	.cra_module	=	THIS_MODULE,
+	.cra_list	=	LIST_HEAD_INIT(alg.cra_list),
+	.cra_u		=	{
+		.digest = {
+			 .dia_digestsize=	CHKSUM_DIGEST_SIZE,
+			 .dia_setkey	=	chksum_setkey,
+			 .dia_init   	= 	chksum_init,
+			 .dia_update 	=	chksum_update,
+			 .dia_final  	=	chksum_final
+		 }
+	}
+};
+
+static int __init init(void)
+{
+	return crypto_register_alg(&alg);
+}
+
+static void __exit fini(void)
+{
+	crypto_unregister_alg(&alg);
+}
+
+module_init(init);
+module_exit(fini);
+
+MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
+MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
+MODULE_LICENSE("GPL");