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

[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
......@@ -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();
......
......@@ -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,
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment