text: // Copyright (c) 2019, The Mask Project
  //
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without modification, are
  // permitted provided that the following conditions are met:
  //
  // 1. Redistributions of source code must retain the above copyright notice, this list of
  //    conditions and the following disclaimer.
  //
  // 2. 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.
  //
  // 3. Neither the name of the copyright holder 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 HOLDER OR CONTRIBUTORS 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.
  
  #include "socks_connect.h"
  
  #include <boost/system/error_code.hpp>
  #include <boost/system/system_error.hpp>
  #include <cstdint>
  #include <memory>
  #include <system_error>
  
  #include "net/error.h"
  #include "net/net_utils_base.h"
  #include "net/socks.h"
  #include "string_tools.h"
  
  namespace net
  {
  namespace socks
  {
      boost::unique_future<boost::asio::ip::tcp::socket>
      connector::operator()(const std::string& remote_host, const std::string& remote_port, boost::asio::steady_timer& timeout) const
      {
          struct future_socket
          {
              boost::promise<boost::asio::ip::tcp::socket> result_;
  
              void operator()(boost::system::error_code error, boost::asio::ip::tcp::socket&& socket)
              {
                  if (error)
                      result_.set_exception(boost::system::system_error{error});
                  else
                      result_.set_value(std::move(socket));
              }
          };
  
          boost::unique_future<boost::asio::ip::tcp::socket> out{};
          {
              std::uint16_t port = 0;
              if (!epee::string_tools::get_xtype_from_string(port, remote_port))
                  throw std::system_error{net::error::invalid_port, "Remote port for socks proxy"};
  
              bool is_set = false;
              std::uint32_t ip_address = 0;
              boost::promise<boost::asio::ip::tcp::socket> result{};
              out = result.get_future();
              const auto proxy = net::socks::make_connect_client(
                  boost::asio::ip::tcp::socket{GET_IO_SERVICE(timeout)}, net::socks::version::v4a, future_socket{std::move(result)}
              );
  
              if (epee::string_tools::get_ip_int32_from_string(ip_address, remote_host))
                  is_set = proxy->set_connect_command(epee::net_utils::ipv4_network_address{ip_address, port});
              else
                  is_set = proxy->set_connect_command(remote_host, port);
  
              if (!is_set || !net::socks::client::connect_and_send(proxy, proxy_address))
                  throw std::system_error{net::error::invalid_host, "Address for socks proxy"};
  
              timeout.async_wait(net::socks::client::async_close{std::move(proxy)});
          }
  
          return out;
      }
  } // socks
  } // net
  