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author | Herbert Xu <herbert@gondor.apana.org.au> | 2007-11-20 10:26:06 +0100 |
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committer | Herbert Xu <herbert@gondor.apana.org.au> | 2008-01-10 22:16:17 +0100 |
commit | 7613636def82092a5c7b6322078a2af832410417 (patch) | |
tree | a05fec8d522e78d21b7b45f9ac330bcd1372e1af /crypto | |
parent | [HIFN]: Add support for using the random number generator (diff) | |
download | linux-7613636def82092a5c7b6322078a2af832410417.tar.xz linux-7613636def82092a5c7b6322078a2af832410417.zip |
[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')
-rw-r--r-- | crypto/algapi.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/crypto/algapi.c b/crypto/algapi.c index 8383282de1dd..08eca6da1d53 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(); |