/*

* (C) 2016 Jack Lloyd

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/rng.h>

#include <botan/entropy_src.h>

#include <botan/loadstor.h>

#include <botan/internal/os_utils.h>

#if defined(BOTAN_HAS_AUTO_SEEDING_RNG)

  #include <botan/auto_rng.h>

#endif

namespace Botan {

void RandomNumberGenerator::randomize_with_ts_input(uint8_t output[], size_t output_len)

   {

   if(this->accepts_input())

      {

      /*

      Form additional input which is provided to the PRNG implementation

      to paramaterize the KDF output.

      */

      uint8_t additional_input[16] = { 0 };

      store_le(OS::get_system_timestamp_ns(), additional_input);

      store_le(OS::get_high_resolution_clock(), additional_input + 8);

      this->randomize_with_input(output, output_len, additional_input, sizeof(additional_input));

      }

   else

      {

      this->randomize(output, output_len);

      }

   }

void RandomNumberGenerator::randomize_with_input(uint8_t output[], size_t output_len,

                                                 const uint8_t input[], size_t input_len)

   {

   this->add_entropy(input, input_len);

   this->randomize(output, output_len);

   }

size_t RandomNumberGenerator::reseed(Entropy_Sources& srcs,

                                     size_t poll_bits,

                                     std::chrono::milliseconds poll_timeout)

   {

   if(this->accepts_input())

      {

      return srcs.poll(*this, poll_bits, poll_timeout);

      }

   else

      {

      return 0;

      }

   }

void RandomNumberGenerator::reseed_from_rng(RandomNumberGenerator& rng, size_t poll_bits)

   {

   if(this->accepts_input())

      {

      secure_vector<uint8_t> buf(poll_bits / 8);

      rng.randomize(buf.data(), buf.size());

      this->add_entropy(buf.data(), buf.size());

      }

   }

RandomNumberGenerator* RandomNumberGenerator::make_rng()

   {

#if defined(BOTAN_HAS_AUTO_SEEDING_RNG)

   return new AutoSeeded_RNG;

#else

   throw Not_Implemented("make_rng failed, no AutoSeeded_RNG in this build");

#endif

   }

#if defined(BOTAN_TARGET_OS_HAS_THREADS)

#if defined(BOTAN_HAS_AUTO_SEEDING_RNG)

Serialized_RNG::Serialized_RNG() : m_rng(new AutoSeeded_RNG) {}

#else

Serialized_RNG::Serialized_RNG()

   {

   throw Not_Implemented("Serialized_RNG default constructor failed: AutoSeeded_RNG disabled in build");

   }

#endif

#endif

}