Botan::POWER9_DARN Class Reference

#include <p9_darn.h>

Inheritance diagram for Botan::POWER9_DARN:

Public Member Functions
std::string	name () const override
size_t	poll (RandomNumberGenerator &rng) override

Static Public Member Functions
static std::unique_ptr< Entropy_Source >	create (const std::string &type)

Detailed Description

Definition at line 14 of file p9_darn.h.

Member Function Documentation

std::unique_ptr< Entropy_Source > Botan::Entropy_Source::create ( const std::string &  type )

staticinherited

Return a new entropy source of a particular type, or null Each entropy source may require substantial resources (eg, a file handle or socket instance), so try to share them among multiple RNGs, or just use the preconfigured global list accessed by Entropy_Sources::global_sources()

Definition at line 67 of file entropy_srcs.cpp.

References BOTAN_UNUSED, and Botan::OS::running_in_privileged_state().

Referenced by Botan::Entropy_Sources::Entropy_Sources().

   {
#if defined(BOTAN_HAS_SYSTEM_RNG)
   if(name == "system_rng" || name == "win32_cryptoapi")
      {
      return std::unique_ptr<Entropy_Source>(new System_RNG_EntropySource);
      }
#endif

#if defined(BOTAN_HAS_ENTROPY_SRC_RDRAND)
   if(name == "rdrand")
      {
      return std::unique_ptr<Entropy_Source>(new Intel_Rdrand);
      }
#endif

#if defined(BOTAN_HAS_ENTROPY_SRC_RDSEED)
   if(name == "rdseed")
      {
      return std::unique_ptr<Entropy_Source>(new Intel_Rdseed);
      }
#endif

#if defined(BOTAN_HAS_ENTROPY_SRC_DARN)
   if(name == "p9_darn")
      {
      return std::unique_ptr<Entropy_Source>(new POWER9_DARN);
      }
#endif

#if defined(BOTAN_HAS_ENTROPY_SRC_GETENTROPY)
   if(name == "getentropy")
      {
      return std::unique_ptr<Entropy_Source>(new Getentropy);
      }
#endif

#if defined(BOTAN_HAS_ENTROPY_SRC_DEV_RANDOM)
   if(name == "dev_random")
      {
      return std::unique_ptr<Entropy_Source>(new Device_EntropySource(BOTAN_SYSTEM_RNG_POLL_DEVICES));
      }
#endif

#if defined(BOTAN_HAS_ENTROPY_SRC_PROC_WALKER)
   if(name == "proc_walk" && OS::running_in_privileged_state() == false)
      {
      const std::string root_dir = BOTAN_ENTROPY_PROC_FS_PATH;
      if(!root_dir.empty())
         return std::unique_ptr<Entropy_Source>(new ProcWalking_EntropySource(root_dir));
      }
#endif

#if defined(BOTAN_HAS_ENTROPY_SRC_WIN32)
   if(name == "system_stats")
      {
      return std::unique_ptr<Entropy_Source>(new Win32_EntropySource);
      }
#endif

   BOTAN_UNUSED(name);
   return std::unique_ptr<Entropy_Source>();
   }

std::string Botan::POWER9_DARN::name ( ) const

inlineoverridevirtual

Returns

name identifying this entropy source

Implements Botan::Entropy_Source.

Definition at line 17 of file p9_darn.h.

{ return "p9_darn"; }

size_t Botan::POWER9_DARN::poll ( RandomNumberGenerator &  rng )

overridevirtual

Perform an entropy gathering poll

Parameters

rng	will be provided with entropy via calls to add_entropy

Returns

conservative estimate of actual entropy added to rng during poll

Implements Botan::Entropy_Source.

Definition at line 38 of file p9_darn.cpp.

References Botan::RandomNumberGenerator::add_entropy().

   {
   const size_t DARN_BYTES = 1024;
   static_assert(DARN_BYTES % 8 == 0, "Bad DARN configuration");

   if(CPUID::has_darn_rng())
      {
      secure_vector<uint64_t> seed;
      seed.reserve(DARN_BYTES / 8);

      for(size_t p = 0; p != DARN_BYTES / 8; ++p)
         {
         if(!read_darn(seed))
            break;
         }

      if(seed.size() > 0)
         {
         rng.add_entropy(reinterpret_cast<const uint8_t*>(seed.data()),
                         seed.size() * sizeof(uint32_t));
         }
      }

   // DARN is used but not trusted
   return 0;
   }

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The documentation for this class was generated from the following files:

• src/lib/entropy/p9_darn/p9_darn.h
• src/lib/entropy/p9_darn/p9_darn.cpp