crypto: chacha20 - Export common ChaCha20 helpers

As architecture specific drivers need a software fallback, export a
ChaCha20 en-/decryption function together with some helpers in a header
file.

Signed-off-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 25 insertions, 0 deletions

diff --git a/include/crypto/chacha20.h b/include/crypto/chacha20.h
new file mode 100644
index 0000000..274bbae
--- /dev/null
+++ b/include/crypto/chacha20.h
@@ -0,0 +1,25 @@
+/*
+ * Common values for the ChaCha20 algorithm
+ */
+
+#ifndef _CRYPTO_CHACHA20_H
+#define _CRYPTO_CHACHA20_H
+
+#include <linux/types.h>
+#include <linux/crypto.h>
+
+#define CHACHA20_IV_SIZE	16
+#define CHACHA20_KEY_SIZE	32
+#define CHACHA20_BLOCK_SIZE	64
+
+struct chacha20_ctx {
+	u32 key[8];
+};
+
+void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv);
+int crypto_chacha20_setkey(struct crypto_tfm *tfm, const u8 *key,
+			   unsigned int keysize);
+int crypto_chacha20_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+			  struct scatterlist *src, unsigned int nbytes);
+
+#endif