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Diffstat (limited to 'boost/beast/websocket/detail/prng.ipp')
| -rw-r--r-- | boost/beast/websocket/detail/prng.ipp | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/boost/beast/websocket/detail/prng.ipp b/boost/beast/websocket/detail/prng.ipp new file mode 100644 index 0000000000..2807ca96e9 --- /dev/null +++ b/boost/beast/websocket/detail/prng.ipp @@ -0,0 +1,327 @@ +// +// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com) +// +// Distributed under the Boost Software License, Version 1.0. (See accompanying +// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +// +// Official repository: https://github.com/boostorg/beast +// + +#ifndef BOOST_BEAST_WEBSOCKET_DETAIL_PRNG_IPP +#define BOOST_BEAST_WEBSOCKET_DETAIL_PRNG_IPP + +#include <boost/beast/websocket/detail/prng.hpp> +#include <boost/beast/core/detail/chacha.hpp> +#include <boost/beast/core/detail/pcg.hpp> +#include <boost/align/aligned_alloc.hpp> +#include <boost/throw_exception.hpp> +#include <atomic> +#include <cstdlib> +#include <mutex> +#include <new> +#include <random> +#include <stdexcept> + +namespace boost { +namespace beast { +namespace websocket { +namespace detail { + +//------------------------------------------------------------------------------ + +std::uint32_t const* +prng_seed(std::seed_seq* ss) +{ + struct data + { + std::uint32_t v[8]; + + explicit + data(std::seed_seq* pss) + { + if(! pss) + { + std::random_device g; + std::seed_seq ss{ + g(), g(), g(), g(), + g(), g(), g(), g()}; + ss.generate(v, v+8); + } + else + { + pss->generate(v, v+8); + } + } + }; + static data const d(ss); + return d.v; +} + +//------------------------------------------------------------------------------ + +template<class T> +class prng_pool +{ + std::mutex m_; + T* head_ = nullptr; + +public: + static + prng_pool& + instance() + { + static prng_pool p; + return p; + } + + ~prng_pool() + { + for(auto p = head_; p;) + { + auto next = p->next; + p->~T(); + boost::alignment::aligned_free(p); + p = next; + } + } + + prng::ref + acquire() + { + { + std::lock_guard< + std::mutex> g(m_); + if(head_) + { + auto p = head_; + head_ = head_->next; + return prng::ref(*p); + } + } + auto p = boost::alignment::aligned_alloc( + 16, sizeof(T)); + if(! p) + BOOST_THROW_EXCEPTION(std::bad_alloc{}); + return prng::ref(*(::new(p) T())); + } + + void + release(T& t) + { + std::lock_guard< + std::mutex> g(m_); + t.next = head_; + head_ = &t; + } +}; + +prng::ref +make_prng_no_tls(bool secure) +{ + class fast_prng final : public prng + { + int refs_ = 0; + beast::detail::pcg r_; + + public: + fast_prng* next = nullptr; + + fast_prng() + : r_( + []{ + auto const pv = prng_seed(); + return + ((static_cast<std::uint64_t>(pv[0])<<32)+pv[1]) ^ + ((static_cast<std::uint64_t>(pv[2])<<32)+pv[3]) ^ + ((static_cast<std::uint64_t>(pv[4])<<32)+pv[5]) ^ + ((static_cast<std::uint64_t>(pv[6])<<32)+pv[7]); + }(), + []{ + static std::atomic< + std::uint32_t> nonce{0}; + return ++nonce; + }()) + { + } + + protected: + prng& + acquire() noexcept override + { + ++refs_; + return *this; + } + + void + release() noexcept override + { + if(--refs_ == 0) + prng_pool<fast_prng>::instance().release(*this); + } + + value_type + operator()() noexcept override + { + return r_(); + } + }; + + class secure_prng final : public prng + { + int refs_ = 0; + beast::detail::chacha<20> r_; + + public: + secure_prng* next = nullptr; + + secure_prng() + : r_(prng_seed(), [] + { + static std::atomic< + std::uint64_t> nonce{0}; + return ++nonce; + }()) + { + } + + protected: + prng& + acquire() noexcept override + { + ++refs_; + return *this; + } + + void + release() noexcept override + { + if(--refs_ == 0) + prng_pool<secure_prng>::instance().release(*this); + } + + value_type + operator()() noexcept override + { + return r_(); + } + }; + + if(secure) + return prng_pool<secure_prng>::instance().acquire(); + + return prng_pool<fast_prng>::instance().acquire(); +} + +//------------------------------------------------------------------------------ + +#ifndef BOOST_NO_CXX11_THREAD_LOCAL + +prng::ref +make_prng_tls(bool secure) +{ + class fast_prng final : public prng + { + beast::detail::pcg r_; + + public: + fast_prng() + : r_( + []{ + auto const pv = prng_seed(); + return + ((static_cast<std::uint64_t>(pv[0])<<32)+pv[1]) ^ + ((static_cast<std::uint64_t>(pv[2])<<32)+pv[3]) ^ + ((static_cast<std::uint64_t>(pv[4])<<32)+pv[5]) ^ + ((static_cast<std::uint64_t>(pv[6])<<32)+pv[7]); + }(), + []{ + static std::atomic< + std::uint32_t> nonce{0}; + return ++nonce; + }()) + { + } + + protected: + prng& + acquire() noexcept override + { + return *this; + } + + void + release() noexcept override + { + } + + value_type + operator()() noexcept override + { + return r_(); + } + }; + + class secure_prng final : public prng + { + beast::detail::chacha<20> r_; + + public: + secure_prng() + : r_(prng_seed(), [] + { + static std::atomic< + std::uint64_t> nonce{0}; + return ++nonce; + }()) + { + } + + protected: + prng& + acquire() noexcept override + { + return *this; + } + + void + release() noexcept override + { + } + + value_type + operator()() noexcept override + { + return r_(); + } + }; + + if(secure) + { + thread_local secure_prng sp; + return prng::ref(sp); + } + + thread_local fast_prng fp; + return prng::ref(fp); +} + +#endif + +//------------------------------------------------------------------------------ + +prng::ref +make_prng(bool secure) +{ +#ifdef BOOST_NO_CXX11_THREAD_LOCAL + return make_prng_no_tls(secure); +#else + return make_prng_tls(secure); +#endif +} + +} // detail +} // websocket +} // beast +} // boost + +#endif |