monero/contrib/epee/include/net/net_helper.h

// Copyright (c) 2006-2013, Andrey N. Sabelnikov, www.sabelnikov.net
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of the Andrey N. Sabelnikov nor the
// names of its contributors may be used to endorse or promote products
// derived from this software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER  BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// 




#pragma once

//#include <Winsock2.h>
//#include <Ws2tcpip.h>
#include <string>
#include <boost/version.hpp>
#include <boost/asio/io_service.hpp>
#include <boost/asio/ip/tcp.hpp>
#include <boost/asio/read.hpp>
#include <boost/asio/ssl.hpp>
#include <boost/asio/steady_timer.hpp>
#include <boost/thread/future.hpp>
#include <boost/lambda/bind.hpp>
#include <boost/lambda/lambda.hpp>
#include <boost/interprocess/detail/atomic.hpp>
#include <boost/system/error_code.hpp>
#include <functional>
#include "net/net_utils_base.h"
#include "net/net_ssl.h"
#include "misc_language.h"

#undef MONERO_DEFAULT_LOG_CATEGORY
#define MONERO_DEFAULT_LOG_CATEGORY "net"

#ifndef MAKE_IP
#define MAKE_IP( a1, a2, a3, a4 )	(a1|(a2<<8)|(a3<<16)|(a4<<24))
#endif


namespace epee
{
namespace net_utils
{
	struct direct_connect
	{
		boost::unique_future<boost::asio::ip::tcp::socket>
			operator()(const std::string& addr, const std::string& port, boost::asio::steady_timer&) const;
	};


  class blocked_mode_client
	{
		enum try_connect_result_t
		{
			CONNECT_SUCCESS,
			CONNECT_FAILURE,
			CONNECT_NO_SSL,
		};

		
		
				struct handler_obj
				{
					handler_obj(boost::system::error_code& error,	size_t& bytes_transferred):ref_error(error), ref_bytes_transferred(bytes_transferred)
					{}
					handler_obj(const handler_obj& other_obj):ref_error(other_obj.ref_error), ref_bytes_transferred(other_obj.ref_bytes_transferred)
					{}

					boost::system::error_code& ref_error;
					size_t& ref_bytes_transferred;

					void operator()(const boost::system::error_code& error, // Result of operation.
						std::size_t bytes_transferred           // Number of bytes read.
						)
					{
						ref_error = error;
						ref_bytes_transferred = bytes_transferred;
					}
				};

	public:
		inline
			blocked_mode_client() :
				m_io_service(),
				m_ctx(boost::asio::ssl::context::tlsv12),
				m_connector(direct_connect{}),
				m_ssl_socket(new boost::asio::ssl::stream<boost::asio::ip::tcp::socket>(m_io_service, m_ctx)),
				m_ssl_options(epee::net_utils::ssl_support_t::e_ssl_support_autodetect),
				m_initialized(true),
				m_connected(false),
				m_deadline(m_io_service),
				m_shutdowned(0),
				m_bytes_sent(0),
				m_bytes_received(0)
		{
		}

		/*! The first/second parameters are host/port respectively. The third
		    parameter is for setting the timeout callback - the timer is
		    already set by the caller, the callee only needs to set the
		    behavior.

		    Additional asynchronous operations should be queued using the
		    `io_service` from the timer. The implementation should assume
		    multi-threaded I/O processing.

		    If the callee cannot start an asynchronous operation, an exception
		    should be thrown to signal an immediate failure.

		    The return value is a future to a connected socket. Asynchronous
		    failures should use the `set_exception` method. */
		using connect_func = boost::unique_future<boost::asio::ip::tcp::socket>(const std::string&, const std::string&, boost::asio::steady_timer&);

		inline
			~blocked_mode_client()
		{
			//profile_tools::local_coast lc("~blocked_mode_client()", 3);
			try { shutdown(); }
			catch(...) { /* ignore */ }
		}

		inline void set_ssl(ssl_options_t ssl_options)
		{
			if (ssl_options)
				m_ctx = ssl_options.create_context();
			else
				m_ctx = boost::asio::ssl::context(boost::asio::ssl::context::tlsv12);
			m_ssl_options = std::move(ssl_options);
		}

    inline
      bool connect(const std::string& addr, int port, std::chrono::milliseconds timeout)
    {
      return connect(addr, std::to_string(port), timeout);
    }

    inline
			try_connect_result_t try_connect(const std::string& addr, const std::string& port, std::chrono::milliseconds timeout, epee::net_utils::ssl_support_t ssl_support)
		{
				m_deadline.expires_from_now(timeout);
				boost::unique_future<boost::asio::ip::tcp::socket> connection = m_connector(addr, port, m_deadline);
				for (;;)
				{
					m_io_service.reset();
					m_io_service.run_one();

					if (connection.is_ready())
						break;
				}

				m_ssl_socket->next_layer() = connection.get();
				m_deadline.cancel();
				if (m_ssl_socket->next_layer().is_open())
				{
					m_connected = true;
					m_deadline.expires_at(std::chrono::steady_clock::time_point::max());
					// SSL Options
					if (ssl_support == epee::net_utils::ssl_support_t::e_ssl_support_enabled || ssl_support == epee::net_utils::ssl_support_t::e_ssl_support_autodetect)
					{
						if (!m_ssl_options.handshake(*m_ssl_socket, boost::asio::ssl::stream_base::client, addr))
						{
							if (ssl_support == epee::net_utils::ssl_support_t::e_ssl_support_autodetect)
							{
								boost::system::error_code ignored_ec;
								m_ssl_socket->next_layer().shutdown(boost::asio::ip::tcp::socket::shutdown_both, ignored_ec);
								m_ssl_socket->next_layer().close();
								m_connected = false;
								return CONNECT_NO_SSL;
							}
							else
							{
								MWARNING("Failed to establish SSL connection");
								m_connected = false;
								return CONNECT_FAILURE;
							}
						}
						m_ssl_options.support = ssl_support_t::e_ssl_support_enabled;
					}
					return CONNECT_SUCCESS;
				}else
				{
					MWARNING("Some problems at connect, expected open socket");
					return CONNECT_FAILURE;
				}

		}

    inline
			bool connect(const std::string& addr, const std::string& port, std::chrono::milliseconds timeout)
		{
			m_connected = false;
			try
			{
				m_ssl_socket->next_layer().close();

				// Set SSL options
				// disable sslv2
				m_ssl_socket.reset(new boost::asio::ssl::stream<boost::asio::ip::tcp::socket>(m_io_service, m_ctx));

				// Get a list of endpoints corresponding to the server name.

				try_connect_result_t try_connect_result = try_connect(addr, port, timeout, m_ssl_options.support);
				if (try_connect_result == CONNECT_FAILURE)
					return false;
				if (m_ssl_options.support == epee::net_utils::ssl_support_t::e_ssl_support_autodetect)
				{
					m_ssl_options.support = epee::net_utils::ssl_support_t::e_ssl_support_enabled;
					if (try_connect_result == CONNECT_NO_SSL)
					{
						MERROR("SSL handshake failed on an autodetect connection, reconnecting without SSL");
						m_ssl_options.support = epee::net_utils::ssl_support_t::e_ssl_support_disabled;
						if (try_connect(addr, port, timeout, m_ssl_options.support) != CONNECT_SUCCESS)
							return false;
					}
				}
			}
			catch(const boost::system::system_error& er)
			{
				MDEBUG("Some problems at connect, message: " << er.what());
				return false;
			}
			catch(...)
			{
				MDEBUG("Some fatal problems.");
				return false;
			}

			return true;
		}
		//! Change the connection routine (proxy, etc.)
		void set_connector(std::function<connect_func> connector)
		{
			m_connector = std::move(connector);
		}

		inline 
		bool disconnect()
		{
			try
			{	
				if(m_connected)
				{
					m_connected = false;
					if(m_ssl_options)
						shutdown_ssl();
					m_ssl_socket->next_layer().shutdown(boost::asio::ip::tcp::socket::shutdown_both);
				}
			}
			catch(const boost::system::system_error& /*er*/)
			{
				//LOG_ERROR("Some problems at disconnect, message: " << er.what());
				return false;
			}
			catch(...)
			{
				//LOG_ERROR("Some fatal problems.");
				return false;
			}
			return true;
		}


		inline 
		bool send(const std::string& buff, std::chrono::milliseconds timeout)
		{

			try
			{
				m_deadline.expires_from_now(timeout);

				// Set up the variable that receives the result of the asynchronous
				// operation. The error code is set to would_block to signal that the
				// operation is incomplete. Asio guarantees that its asynchronous
				// operations will never fail with would_block, so any other value in
				// ec indicates completion.
				boost::system::error_code ec = boost::asio::error::would_block;

				// Start the asynchronous operation itself. The boost::lambda function
				// object is used as a callback and will update the ec variable when the
				// operation completes. The blocking_udp_client.cpp example shows how you
				// can use boost::bind rather than boost::lambda.
				async_write(buff.c_str(), buff.size(), ec);

				// Block until the asynchronous operation has completed.
				while (ec == boost::asio::error::would_block)
				{
					m_io_service.reset();
					m_io_service.run_one(); 
				}

				if (ec)
				{
					LOG_PRINT_L3("Problems at write: " << ec.message());
          m_connected = false;
					return false;
				}else
				{
					m_deadline.expires_at(std::chrono::steady_clock::time_point::max());
					m_bytes_sent += buff.size();
				}
			}

			catch(const boost::system::system_error& er)
			{
				LOG_ERROR("Some problems at connect, message: " << er.what());
				return false;
			}
			catch(...)
			{
				LOG_ERROR("Some fatal problems.");
				return false;
			}

			return true;
		}

		inline 
			bool send(const void* data, size_t sz)
		{
			try
			{
				/*
				m_deadline.expires_from_now(boost::posix_time::milliseconds(m_reciev_timeout));

				// Set up the variable that receives the result of the asynchronous
				// operation. The error code is set to would_block to signal that the
				// operation is incomplete. Asio guarantees that its asynchronous
				// operations will never fail with would_block, so any other value in
				// ec indicates completion.
				boost::system::error_code ec = boost::asio::error::would_block;

				// Start the asynchronous operation itself. The boost::lambda function
				// object is used as a callback and will update the ec variable when the
				// operation completes. The blocking_udp_client.cpp example shows how you
				// can use boost::bind rather than boost::lambda.
				boost::asio::async_write(m_socket, boost::asio::buffer(data, sz), boost::lambda::var(ec) = boost::lambda::_1);

				// Block until the asynchronous operation has completed.
				while (ec == boost::asio::error::would_block)
				{
					m_io_service.run_one();
				}
				*/
				boost::system::error_code ec;

				size_t writen = write(data, sz, ec);

				if (!writen || ec)
				{
					LOG_PRINT_L3("Problems at write: " << ec.message());
          m_connected = false;
					return false;
				}else
				{
					m_deadline.expires_at(std::chrono::steady_clock::time_point::max());
					m_bytes_sent += sz;
				}
			}

			catch(const boost::system::system_error& er)
			{
				LOG_ERROR("Some problems at send, message: " << er.what());
        m_connected = false;
				return false;
			}
			catch(...)
			{
				LOG_ERROR("Some fatal problems.");
				return false;
			}

			return true;
		}

		bool is_connected(bool *ssl = NULL)
		{
			if (!m_connected || !m_ssl_socket->next_layer().is_open())
				return false;
			if (ssl)
				*ssl = m_ssl_options.support == ssl_support_t::e_ssl_support_enabled;
			return true;
		}

		inline 
		bool recv(std::string& buff, std::chrono::milliseconds timeout)
		{

			try
			{
				// Set a deadline for the asynchronous operation. Since this function uses
				// a composed operation (async_read_until), the deadline applies to the
				// entire operation, rather than individual reads from the socket.
				m_deadline.expires_from_now(timeout);

				// Set up the variable that receives the result of the asynchronous
				// operation. The error code is set to would_block to signal that the
				// operation is incomplete. Asio guarantees that its asynchronous
				// operations will never fail with would_block, so any other value in
				// ec indicates completion.
				//boost::system::error_code ec = boost::asio::error::would_block;

				// Start the asynchronous operation itself. The boost::lambda function
				// object is used as a callback and will update the ec variable when the
				// operation completes. The blocking_udp_client.cpp example shows how you
				// can use boost::bind rather than boost::lambda.

				boost::system::error_code ec = boost::asio::error::would_block;
				size_t bytes_transfered = 0;
			
				handler_obj hndlr(ec, bytes_transfered);

				static const size_t max_size = 16384;
				buff.resize(max_size);
				
				async_read(&buff[0], max_size, boost::asio::transfer_at_least(1), hndlr);

				// Block until the asynchronous operation has completed.
				while (ec == boost::asio::error::would_block && !boost::interprocess::ipcdetail::atomic_read32(&m_shutdowned))
				{
					m_io_service.reset();
					m_io_service.run_one(); 
				}


				if (ec)
				{
                    MTRACE("READ ENDS: Connection err_code " << ec.value());
                    if(ec == boost::asio::error::eof)
                    {
                      MTRACE("Connection err_code eof.");
                      //connection closed there, empty
                      buff.clear();
                      return true;
                    }

					MDEBUG("Problems at read: " << ec.message());
                    m_connected = false;
					return false;
				}else
				{
                    MTRACE("READ ENDS: Success. bytes_tr: " << bytes_transfered);
					m_deadline.expires_at(std::chrono::steady_clock::time_point::max());
				}

				/*if(!bytes_transfered)
					return false;*/

				m_bytes_received += bytes_transfered;
				buff.resize(bytes_transfered);
				return true;
			}

			catch(const boost::system::system_error& er)
			{
				LOG_ERROR("Some problems at read, message: " << er.what());
        m_connected = false;
				return false;
			}
			catch(...)
			{
				LOG_ERROR("Some fatal problems at read.");
				return false;
			}



			return false;

		}

		inline bool recv_n(std::string& buff, int64_t sz, std::chrono::milliseconds timeout)
		{

			try
			{
				// Set a deadline for the asynchronous operation. Since this function uses
				// a composed operation (async_read_until), the deadline applies to the
				// entire operation, rather than individual reads from the socket.
				m_deadline.expires_from_now(timeout);

				// Set up the variable that receives the result of the asynchronous
				// operation. The error code is set to would_block to signal that the
				// operation is incomplete. Asio guarantees that its asynchronous
				// operations will never fail with would_block, so any other value in
				// ec indicates completion.
				//boost::system::error_code ec = boost::asio::error::would_block;

				// Start the asynchronous operation itself. The boost::lambda function
				// object is used as a callback and will update the ec variable when the
				// operation completes. The blocking_udp_client.cpp example shows how you
				// can use boost::bind rather than boost::lambda.

				buff.resize(static_cast<size_t>(sz));
				boost::system::error_code ec = boost::asio::error::would_block;
				size_t bytes_transfered = 0;

				
				handler_obj hndlr(ec, bytes_transfered);
				async_read((char*)buff.data(), buff.size(), boost::asio::transfer_at_least(buff.size()), hndlr);
				
				// Block until the asynchronous operation has completed.
				while (ec == boost::asio::error::would_block && !boost::interprocess::ipcdetail::atomic_read32(&m_shutdowned))
				{
					m_io_service.run_one(); 
				}

				if (ec)
				{
					LOG_PRINT_L3("Problems at read: " << ec.message());
          m_connected = false;
					return false;
				}else
				{
					m_deadline.expires_at(std::chrono::steady_clock::time_point::max());
				}

				m_bytes_received += bytes_transfered;
				if(bytes_transfered != buff.size())
				{
					LOG_ERROR("Transferred mismatch with transfer_at_least value: m_bytes_transferred=" << bytes_transfered << " at_least value=" << buff.size());
					return false;
				}

				return true;
			}

			catch(const boost::system::system_error& er)
			{
				LOG_ERROR("Some problems at read, message: " << er.what());
        m_connected = false;
				return false;
			}
			catch(...)
			{
				LOG_ERROR("Some fatal problems at read.");
				return false;
			}



			return false;
		}
		
		bool shutdown()
		{
			m_deadline.cancel();
			boost::system::error_code ec;
			if(m_ssl_options.support != ssl_support_t::e_ssl_support_disabled)
				shutdown_ssl();
			m_ssl_socket->next_layer().cancel(ec);
			if(ec)
				MDEBUG("Problems at cancel: " << ec.message());
			m_ssl_socket->next_layer().shutdown(boost::asio::ip::tcp::socket::shutdown_both, ec);
			if(ec)
				MDEBUG("Problems at shutdown: " << ec.message());
			m_ssl_socket->next_layer().close(ec);
			if(ec)
				MDEBUG("Problems at close: " << ec.message());
			boost::interprocess::ipcdetail::atomic_write32(&m_shutdowned, 1);
      m_connected = false;
			return true;
		}
		
		boost::asio::io_service& get_io_service()
		{
			return m_io_service;
		}

		boost::asio::ip::tcp::socket& get_socket()
		{
			return m_ssl_socket->next_layer();
		}

		uint64_t get_bytes_sent() const
		{
			return m_bytes_sent;
		}

		uint64_t get_bytes_received() const
		{
			return m_bytes_received;
		}

	private:

		void check_deadline()
		{
			// Check whether the deadline has passed. We compare the deadline against
			// the current time since a new asynchronous operation may have moved the
			// deadline before this actor had a chance to run.
			if (m_deadline.expires_at() <= std::chrono::steady_clock::now())
			{
				// The deadline has passed. The socket is closed so that any outstanding
				// asynchronous operations are cancelled. This allows the blocked
				// connect(), read_line() or write_line() functions to return.
				LOG_PRINT_L3("Timed out socket");
        m_connected = false;
				m_ssl_socket->next_layer().close();

				// There is no longer an active deadline. The expiry is set to positive
				// infinity so that the actor takes no action until a new deadline is set.
				m_deadline.expires_at(std::chrono::steady_clock::time_point::max());
			}

			// Put the actor back to sleep.
			m_deadline.async_wait(boost::bind(&blocked_mode_client::check_deadline, this));
		}

		void shutdown_ssl() {
			// ssl socket shutdown blocks if server doesn't respond. We close after 2 secs
			boost::system::error_code ec = boost::asio::error::would_block;
			m_deadline.expires_from_now(std::chrono::milliseconds(2000));
			m_ssl_socket->async_shutdown(boost::lambda::var(ec) = boost::lambda::_1);
			while (ec == boost::asio::error::would_block)
			{
				m_io_service.reset();
				m_io_service.run_one();
			}
			// Ignore "short read" error
			if (ec.category() == boost::asio::error::get_ssl_category() &&
			    ec.value() !=
#if BOOST_VERSION >= 106200
			    boost::asio::ssl::error::stream_truncated
#else // older Boost supports only OpenSSL 1.0, so 1.0-only macros are appropriate
			    ERR_PACK(ERR_LIB_SSL, 0, SSL_R_SHORT_READ)
#endif
			    )
				MDEBUG("Problems at ssl shutdown: " << ec.message());
		}
		
	protected:
		bool write(const void* data, size_t sz, boost::system::error_code& ec)
		{
			bool success;
			if(m_ssl_options.support == ssl_support_t::e_ssl_support_enabled)
				success = boost::asio::write(*m_ssl_socket, boost::asio::buffer(data, sz), ec);
			else
				success = boost::asio::write(m_ssl_socket->next_layer(), boost::asio::buffer(data, sz), ec);
			return success;
		}
		
		void async_write(const void* data, size_t sz, boost::system::error_code& ec) 
		{
			if(m_ssl_options.support == ssl_support_t::e_ssl_support_enabled)
				boost::asio::async_write(*m_ssl_socket, boost::asio::buffer(data, sz), boost::lambda::var(ec) = boost::lambda::_1);
			else
				boost::asio::async_write(m_ssl_socket->next_layer(), boost::asio::buffer(data, sz), boost::lambda::var(ec) = boost::lambda::_1);
		}
		
		void async_read(char* buff, size_t sz, boost::asio::detail::transfer_at_least_t transfer_at_least, handler_obj& hndlr)
		{
			if(m_ssl_options.support != ssl_support_t::e_ssl_support_enabled)
				boost::asio::async_read(m_ssl_socket->next_layer(), boost::asio::buffer(buff, sz), transfer_at_least, hndlr);
			else
				boost::asio::async_read(*m_ssl_socket, boost::asio::buffer(buff, sz), transfer_at_least, hndlr);
			
		}
		
	protected:
		boost::asio::io_service m_io_service;
		boost::asio::ssl::context m_ctx;
		std::shared_ptr<boost::asio::ssl::stream<boost::asio::ip::tcp::socket>> m_ssl_socket;
		std::function<connect_func> m_connector;
		ssl_options_t m_ssl_options;
		bool m_initialized;
		bool m_connected;
		boost::asio::steady_timer m_deadline;
		volatile uint32_t m_shutdowned;
		std::atomic<uint64_t> m_bytes_sent;
		std::atomic<uint64_t> m_bytes_received;
	};


	/************************************************************************/
	/*                                                                      */
	/************************************************************************/
	class async_blocked_mode_client: public blocked_mode_client
	{
	public:
		async_blocked_mode_client():m_send_deadline(blocked_mode_client::m_io_service)
		{

			// No deadline is required until the first socket operation is started. We
			// set the deadline to positive infinity so that the actor takes no action
			// until a specific deadline is set.
			m_send_deadline.expires_at(boost::posix_time::pos_infin);

			// Start the persistent actor that checks for deadline expiry.
			check_send_deadline();
		}
		~async_blocked_mode_client()
		{
			m_send_deadline.cancel();
		}
		
		bool shutdown()
		{
			blocked_mode_client::shutdown();
			m_send_deadline.cancel();
			return true;
		}

		inline 
			bool send(const void* data, size_t sz)
		{
			try
			{
				/*
				m_send_deadline.expires_from_now(boost::posix_time::milliseconds(m_reciev_timeout));

				// Set up the variable that receives the result of the asynchronous
				// operation. The error code is set to would_block to signal that the
				// operation is incomplete. Asio guarantees that its asynchronous
				// operations will never fail with would_block, so any other value in
				// ec indicates completion.
				boost::system::error_code ec = boost::asio::error::would_block;

				// Start the asynchronous operation itself. The boost::lambda function
				// object is used as a callback and will update the ec variable when the
				// operation completes. The blocking_udp_client.cpp example shows how you
				// can use boost::bind rather than boost::lambda.
				boost::asio::async_write(m_socket, boost::asio::buffer(data, sz), boost::lambda::var(ec) = boost::lambda::_1);

				// Block until the asynchronous operation has completed.
				while(ec == boost::asio::error::would_block)
				{
					m_io_service.run_one();
				}*/
				
				boost::system::error_code ec;

				size_t writen = write(data, sz, ec);
				
				if (!writen || ec)
				{
					LOG_PRINT_L3("Problems at write: " << ec.message());
					return false;
				}else
				{
					m_send_deadline.expires_at(boost::posix_time::pos_infin);
				}
			}

			catch(const boost::system::system_error& er)
			{
				LOG_ERROR("Some problems at connect, message: " << er.what());
				return false;
			}
			catch(...)
			{
				LOG_ERROR("Some fatal problems.");
				return false;
			}

			return true;
		}


	private:

		boost::asio::deadline_timer m_send_deadline;

		void check_send_deadline()
		{
			// Check whether the deadline has passed. We compare the deadline against
			// the current time since a new asynchronous operation may have moved the
			// deadline before this actor had a chance to run.
			if (m_send_deadline.expires_at() <= boost::asio::deadline_timer::traits_type::now())
			{
				// The deadline has passed. The socket is closed so that any outstanding
				// asynchronous operations are cancelled. This allows the blocked
				// connect(), read_line() or write_line() functions to return.
				LOG_PRINT_L3("Timed out socket");
				m_ssl_socket->next_layer().close();

				// There is no longer an active deadline. The expiry is set to positive
				// infinity so that the actor takes no action until a new deadline is set.
				m_send_deadline.expires_at(boost::posix_time::pos_infin);
			}

			// Put the actor back to sleep.
			m_send_deadline.async_wait(boost::bind(&async_blocked_mode_client::check_send_deadline, this));
		}
	};
}
}