crypto: rng - RNG interface and implementation

This patch adds a random number generator interface as well as a
cryptographic pseudo-random number generator based on AES.  It is
meant to be used in cases where a deterministic CPRNG is required.

One of the first applications will be as an input in the IPsec IV
generation process.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/crypto/internal/rng.h

@@ -0,0 +1,26 @@
+/*
+ * RNG: Random Number Generator  algorithms under the crypto API
+ *
+ * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#ifndef _CRYPTO_INTERNAL_RNG_H
+#define _CRYPTO_INTERNAL_RNG_H
+
+#include <crypto/algapi.h>
+#include <crypto/rng.h>
+
+extern const struct crypto_type crypto_rng_type;
+
+static inline void *crypto_rng_ctx(struct crypto_rng *tfm)
+{
+	return crypto_tfm_ctx(&tfm->base);
+}
+
+#endif

include/crypto/rng.h

@@ -0,0 +1,75 @@
+/*
+ * RNG: Random Number Generator  algorithms under the crypto API
+ *
+ * Copyright (c) 2008 Neil Horman <nhorman@tuxdriver.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#ifndef _CRYPTO_RNG_H
+#define _CRYPTO_RNG_H
+
+#include <linux/crypto.h>
+
+extern struct crypto_rng *crypto_default_rng;
+
+int crypto_get_default_rng(void);
+void crypto_put_default_rng(void);
+
+static inline struct crypto_rng *__crypto_rng_cast(struct crypto_tfm *tfm)
+{
+	return (struct crypto_rng *)tfm;
+}
+
+static inline struct crypto_rng *crypto_alloc_rng(const char *alg_name,
+						  u32 type, u32 mask)
+{
+	type &= ~CRYPTO_ALG_TYPE_MASK;
+	type |= CRYPTO_ALG_TYPE_RNG;
+	mask |= CRYPTO_ALG_TYPE_MASK;
+
+	return __crypto_rng_cast(crypto_alloc_base(alg_name, type, mask));
+}
+
+static inline struct crypto_tfm *crypto_rng_tfm(struct crypto_rng *tfm)
+{
+	return &tfm->base;
+}
+
+static inline struct rng_alg *crypto_rng_alg(struct crypto_rng *tfm)
+{
+	return &crypto_rng_tfm(tfm)->__crt_alg->cra_rng;
+}
+
+static inline struct rng_tfm *crypto_rng_crt(struct crypto_rng *tfm)
+{
+	return &crypto_rng_tfm(tfm)->crt_rng;
+}
+
+static inline void crypto_free_rng(struct crypto_rng *tfm)
+{
+	crypto_free_tfm(crypto_rng_tfm(tfm));
+}
+
+static inline int crypto_rng_get_bytes(struct crypto_rng *tfm,
+				       u8 *rdata, unsigned int dlen)
+{
+	return crypto_rng_crt(tfm)->rng_gen_random(tfm, rdata, dlen);
+}
+
+static inline int crypto_rng_reset(struct crypto_rng *tfm,
+				   u8 *seed, unsigned int slen)
+{
+	return crypto_rng_crt(tfm)->rng_reset(tfm, seed, slen);
+}
+
+static inline int crypto_rng_seedsize(struct crypto_rng *tfm)
+{
+	return crypto_rng_alg(tfm)->seedsize;
+}
+
+#endif