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-rw-r--r--crypto/crc32c.c110
1 files changed, 110 insertions, 0 deletions
diff --git a/crypto/crc32c.c b/crypto/crc32c.c
new file mode 100644
index 000000000000..256956cd9377
--- /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");