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Commit 7613636d authored by Herbert Xu's avatar Herbert Xu
Browse files

[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: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent fcd06755

crypto/algapi.c

+47 −0
Original line number Diff line number Diff line
@@ -605,6 +605,53 @@ int crypto_tfm_in_queue(struct crypto_queue *queue, struct crypto_tfm *tfm) 
}

EXPORT_SYMBOL_GPL(crypto_tfm_in_queue);



static inline void crypto_inc_byte(u8 *a, unsigned int size)

{

	u8 *b = (a + size);

	u8 c;



	for (; size; size--) {

		c = *--b + 1;

		*b = c;

		if (c)

			break;

	}

}



void crypto_inc(u8 *a, unsigned int size)

{

	__be32 *b = (__be32 *)(a + size);

	u32 c;



	for (; size >= 4; size -= 4) {

		c = be32_to_cpu(*--b) + 1;

		*b = cpu_to_be32(c);

		if (c)

			return;

	}



	crypto_inc_byte(a, size);

}

EXPORT_SYMBOL_GPL(crypto_inc);



static inline void crypto_xor_byte(u8 *a, const u8 *b, unsigned int size)

{

	for (; size; size--)

		*a++ ^= *b++;

}



void crypto_xor(u8 *dst, const u8 *src, unsigned int size)

{

	u32 *a = (u32 *)dst;

	u32 *b = (u32 *)src;



	for (; size >= 4; size -= 4)

		*a++ ^= *b++;



	crypto_xor_byte((u8 *)a, (u8 *)b, size);

}

EXPORT_SYMBOL_GPL(crypto_xor);



static int __init crypto_algapi_init(void)

{

	crypto_init_proc();

include/crypto/algapi.h

+4 −0
Original line number Diff line number Diff line
@@ -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,