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authorHerbert Xu <herbert@gondor.apana.org.au>2007-11-20 17:26:06 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2008-01-11 08:16:17 +1100
commit7613636def82092a5c7b6322078a2af832410417 (patch)
treea05fec8d522e78d21b7b45f9ac330bcd1372e1af /crypto/algapi.c
parentfcd06755936d2209b69650d2a7cc99cbcd3ccc67 (diff)
downloadlinux-7613636def82092a5c7b6322078a2af832410417.tar.gz
[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>
Diffstat (limited to 'crypto/algapi.c')
-rw-r--r--crypto/algapi.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/crypto/algapi.c b/crypto/algapi.c
index 8383282de1d..08eca6da1d5 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -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();