[CRYPTO] api: Add crypto_inc and crypto_xor

With the addition of more stream ciphers we need to curb the proliferation
of ad-hoc xor functions.  This patch creates a generic pair of functions,
crypto_inc and crypto_xor which does big-endian increment and exclusive or,
respectively.

For optimum performance, they both use u32 operations so alignment must be
as that of u32 even though the arguments are of type u8 *.

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

1 files changed, 4 insertions, 0 deletions

diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index 88619f9..2cdb227 100644
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -124,6 +124,10 @@ int crypto_enqueue_request(struct crypto_queue *queue,
 struct crypto_async_request *crypto_dequeue_request(struct crypto_queue *queue);
 int crypto_tfm_in_queue(struct crypto_queue *queue, struct crypto_tfm *tfm);
 
+/* These functions require the input/output to be aligned as u32. */
+void crypto_inc(u8 *a, unsigned int size);
+void crypto_xor(u8 *dst, const u8 *src, unsigned int size);
+
 int blkcipher_walk_done(struct blkcipher_desc *desc,
 			struct blkcipher_walk *walk, int err);
 int blkcipher_walk_virt(struct blkcipher_desc *desc,