crypto: poly1305 - Export common Poly1305 helpers

As architecture specific drivers need a software fallback, export Poly1305
init/update/final functions 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>

include/crypto/poly1305.h

@@ -0,0 +1,41 @@
+/*
+ * Common values for the Poly1305 algorithm
+ */
+
+#ifndef _CRYPTO_POLY1305_H
+#define _CRYPTO_POLY1305_H
+
+#include <linux/types.h>
+#include <linux/crypto.h>
+
+#define POLY1305_BLOCK_SIZE	16
+#define POLY1305_KEY_SIZE	32
+#define POLY1305_DIGEST_SIZE	16
+
+struct poly1305_desc_ctx {
+	/* key */
+	u32 r[5];
+	/* finalize key */
+	u32 s[4];
+	/* accumulator */
+	u32 h[5];
+	/* partial buffer */
+	u8 buf[POLY1305_BLOCK_SIZE];
+	/* bytes used in partial buffer */
+	unsigned int buflen;
+	/* r key has been set */
+	bool rset;
+	/* s key has been set */
+	bool sset;
+};
+
+int crypto_poly1305_init(struct shash_desc *desc);
+int crypto_poly1305_setkey(struct crypto_shash *tfm,
+			   const u8 *key, unsigned int keylen);
+unsigned int crypto_poly1305_setdesckey(struct poly1305_desc_ctx *dctx,
+					const u8 *src, unsigned int srclen);
+int crypto_poly1305_update(struct shash_desc *desc,
+			   const u8 *src, unsigned int srclen);
+int crypto_poly1305_final(struct shash_desc *desc, u8 *dst);
+
+#endif