summaryrefslogtreecommitdiffstats
path: root/lib/libcrc32c.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/libcrc32c.c')
-rw-r--r--lib/libcrc32c.c74
1 files changed, 74 insertions, 0 deletions
diff --git a/lib/libcrc32c.c b/lib/libcrc32c.c
new file mode 100644
index 0000000000..649e687413
--- /dev/null
+++ b/lib/libcrc32c.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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 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.
+ */
+
+#include <crypto/hash.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/crc32c.h>
+
+static struct crypto_shash *tfm;
+
+u32 crc32c(u32 crc, const void *address, unsigned int length)
+{
+ SHASH_DESC_ON_STACK(shash, tfm);
+ u32 ret, *ctx = (u32 *)shash_desc_ctx(shash);
+ int err;
+
+ shash->tfm = tfm;
+ *ctx = crc;
+
+ err = crypto_shash_update(shash, address, length);
+ BUG_ON(err);
+
+ ret = *ctx;
+ barrier_data(ctx);
+ return ret;
+}
+
+EXPORT_SYMBOL(crc32c);
+
+static int __init libcrc32c_mod_init(void)
+{
+ tfm = crypto_alloc_shash("crc32c", 0, 0);
+ return PTR_ERR_OR_ZERO(tfm);
+}
+
+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");
+MODULE_SOFTDEP("pre: crc32c");