/* random.h
 *
 * Copyright (C) 2006-2017 wolfSSL Inc.
 *
 * This file is part of wolfSSL.
 *
 * wolfSSL 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.
 *
 * wolfSSL is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
 */


#ifndef WOLF_CRYPT_RANDOM_H
# define WOLF_CRYPT_RANDOM_H

# include "types.h"

# ifdef HAVE_FIPS
/* for fips @wc_fips */
#  include <cyassl/ctaocrypt/random.h>
# endif

# ifdef __cplusplus
extern "C" {
# endif

/* Maximum generate block length */
# ifndef RNG_MAX_BLOCK_LEN
#  ifdef HAVE_INTEL_QA
#   define RNG_MAX_BLOCK_LEN (0xFFFF)
#  else
#   define RNG_MAX_BLOCK_LEN (0x10000)
#  endif
# endif

/* Size of the BRBG seed */
# ifndef DRBG_SEED_LEN
#  define DRBG_SEED_LEN (440 / 8)
# endif


# if !defined(CUSTOM_RAND_TYPE)
/* To maintain compatibility the default is byte */
#  define CUSTOM_RAND_TYPE byte
# endif

/* make sure Hash DRBG is enabled, unless WC_NO_HASHDRBG is defined
 *  or CUSTOM_RAND_GENERATE_BLOCK is defined*/
# if !defined(WC_NO_HASHDRBG) || !defined(CUSTOM_RAND_GENERATE_BLOCK)
#  undef  HAVE_HASHDRBG
#  define HAVE_HASHDRBG
#  ifndef WC_RESEED_INTERVAL
#   define WC_RESEED_INTERVAL (1000000)
#  endif
# endif


# ifndef HAVE_FIPS /* avoid redefining structs and macros */

/* RNG supports the following sources (in order):
 * 1. CUSTOM_RAND_GENERATE_BLOCK: Defines name of function as RNG source and
 *     bypasses the options below.
 * 2. HAVE_INTEL_RDRAND: Uses the Intel RDRAND if supported by CPU.
 * 3. HAVE_HASHDRBG (requires SHA256 enabled): Uses SHA256 based P-RNG
 *     seeded via wc_GenerateSeed. This is the default source.
 */

/* Seed source can be overriden by defining one of these:
 *   CUSTOM_RAND_GENERATE_SEED
 *   CUSTOM_RAND_GENERATE_SEED_OS
 *   CUSTOM_RAND_GENERATE */


#  if defined(CUSTOM_RAND_GENERATE_BLOCK)

/* To use define the following:
 * #define CUSTOM_RAND_GENERATE_BLOCK myRngFunc
 * extern int myRngFunc(byte* output, word32 sz);
 */
#  elif defined(HAVE_HASHDRBG)
#   ifdef NO_SHA256
#    error "Hash DRBG requires SHA-256."
#   endif /* NO_SHA256 */
#   include "sha256.h"
#  elif defined(HAVE_WNR)
/* allow whitewood as direct RNG source using wc_GenerateSeed directly */
#  else
#   error No RNG source defined!
#  endif // if defined(CUSTOM_RAND_GENERATE_BLOCK)

#  ifdef HAVE_WNR
#   include <wnr.h>
#  endif

#  ifdef WOLFSSL_ASYNC_CRYPT
#   include <wolfssl/wolfcrypt/async.h>
#  endif


#  if defined(USE_WINDOWS_API)
#   if defined(_WIN64)
typedef unsigned __int64 ProviderHandle;
/* type HCRYPTPROV, avoid #include <windows.h> */
#   else
typedef unsigned long ProviderHandle;
#   endif
#  endif


/* OS specific seeder */
typedef struct OS_Seed {
    #  if defined(USE_WINDOWS_API)
    ProviderHandle handle;
    #  else
    int            fd;
    #  endif
} OS_Seed;


#  ifndef WC_RNG_TYPE_DEFINED /* guard on redeclaration */
typedef struct WC_RNG WC_RNG;
#   define WC_RNG_TYPE_DEFINED
#  endif

#  ifdef HAVE_HASHDRBG
/* Private DRBG state */
struct DRBG;
#  endif

/* RNG context */
struct WC_RNG {
    OS_Seed       seed;
    void *        heap;
    #  ifdef HAVE_HASHDRBG
    /* Hash-based Deterministic Random Bit Generator */
    struct DRBG * drbg;
    byte          status;
    #  endif
    #  ifdef WOLFSSL_ASYNC_CRYPT
    WC_ASYNC_DEV  asyncDev;
    int           devId;
    #  endif
};

# endif /* HAVE_FIPS */

/* NO_OLD_RNGNAME removes RNG struct name to prevent possible type conflicts,
 * can't be used with CTaoCrypt FIPS */
# if !defined(NO_OLD_RNGNAME) && !defined(HAVE_FIPS)
#  define RNG WC_RNG
# endif


WOLFSSL_LOCAL
int
wc_GenerateSeed(OS_Seed * os, byte * seed, word32 sz);


# ifdef HAVE_WNR
/* Whitewood netRandom client library */
WOLFSSL_API int wc_InitNetRandom(const char *, wnr_hmac_key, int);
WOLFSSL_API int
wc_FreeNetRandom(void);
# endif /* HAVE_WNR */


WOLFSSL_API int
wc_InitRng(WC_RNG *);
WOLFSSL_API int
wc_InitRng_ex(WC_RNG * rng, void * heap, int devId);
WOLFSSL_API int
wc_RNG_GenerateBlock(WC_RNG *, byte *, word32 sz);
WOLFSSL_API int
wc_RNG_GenerateByte(WC_RNG *, byte *);
WOLFSSL_API int
wc_FreeRng(WC_RNG *);


# ifdef HAVE_HASHDRBG
WOLFSSL_API int
wc_RNG_HealthTest(int reseed,
  const byte * entropyA, word32 entropyASz,
  const byte * entropyB, word32 entropyBSz,
  byte * output, word32 outputSz);
# endif /* HAVE_HASHDRBG */

# ifdef __cplusplus
} /* extern "C" */
# endif

#endif /* WOLF_CRYPT_RANDOM_H */
