crypto: salsa20 - export generic helpers

Export the Salsa20 constants, transform context, and initialization
functions so that they can be reused by the x86 implementation.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 27 insertions, 0 deletions

diff --git a/include/crypto/salsa20.h b/include/crypto/salsa20.h
new file mode 100644
index 000000000000..19ed48aefc86
--- /dev/null
+++ b/include/crypto/salsa20.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Common values for the Salsa20 algorithm
+ */
+
+#ifndef _CRYPTO_SALSA20_H
+#define _CRYPTO_SALSA20_H
+
+#include <linux/types.h>
+
+#define SALSA20_IV_SIZE		8
+#define SALSA20_MIN_KEY_SIZE	16
+#define SALSA20_MAX_KEY_SIZE	32
+#define SALSA20_BLOCK_SIZE	64
+
+struct crypto_skcipher;
+
+struct salsa20_ctx {
+	u32 initial_state[16];
+};
+
+void crypto_salsa20_init(u32 *state, const struct salsa20_ctx *ctx,
+			 const u8 *iv);
+int crypto_salsa20_setkey(struct crypto_skcipher *tfm, const u8 *key,
+			  unsigned int keysize);
+
+#endif /* _CRYPTO_SALSA20_H */