initial_commit

1 files changed, 81 insertions, 0 deletions

diff --git a/lib/libcrc32c.c b/lib/libcrc32c.c
new file mode 100644
index 00000000..244f5480
--- /dev/null
+++ b/lib/libcrc32c.c
@@ -0,0 +1,81 @@
+/* 
+ * CRC32C
+ *@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.
+ * 
+ * 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/hash.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+static struct crypto_shash *tfm;
+
+u32 crc32c(u32 crc, const void *address, unsigned int length)
+{
+	struct {
+		struct shash_desc shash;
+		char ctx[crypto_shash_descsize(tfm)];
+	} desc;
+	int err;
+
+	desc.shash.tfm = tfm;
+	desc.shash.flags = 0;
+	*(u32 *)desc.ctx = crc;
+
+	err = crypto_shash_update(&desc.shash, address, length);
+	BUG_ON(err);
+
+	return *(u32 *)desc.ctx;
+}
+
+EXPORT_SYMBOL(crc32c);
+
+static int __init libcrc32c_mod_init(void)
+{
+	tfm = crypto_alloc_shash("crc32c", 0, 0);
+	if (IS_ERR(tfm))
+		return PTR_ERR(tfm);
+
+	return 0;
+}
+
+static void __exit libcrc32c_mod_fini(void)
+{
+	crypto_free_shash(tfm);
+}
+
+module_init(libcrc32c_mod_init);
+module_exit(libcrc32c_mod_fini);
+
+MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
+MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
+MODULE_LICENSE("GPL");