text: // Copyright (c) 2011-2017 The Cryptonote developers
  // Copyright (c) 2017-2018 The Circle Foundation & Conceal Devs
  // Copyright (c) 2018-2019 Conceal Network & Conceal Devs
  // Distributed under the MIT/X11 software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include "TcpConnector.h"
  #include <cassert>
  #ifndef WIN32_LEAN_AND_MEAN
  #define WIN32_LEAN_AND_MEAN
  #endif
  #include <winsock2.h>
  #include <mswsock.h>
  #include <System/InterruptedException.h>
  #include <System/Ipv4Address.h>
  #include "Dispatcher.h"
  #include "ErrorMessage.h"
  #include "TcpConnection.h"
  #include <stdexcept>
  
  namespace System {
  
  namespace {
  
  struct TcpConnectorContext : public OVERLAPPED {
    NativeContext* context;
    uint64_t connection;
    bool interrupted;
  };
  
  LPFN_CONNECTEX connectEx = nullptr;
  
  }
  
  TcpConnector::TcpConnector() : dispatcher(nullptr) {
  }
  
  TcpConnector::TcpConnector(Dispatcher& dispatcher) : dispatcher(&dispatcher), context(nullptr) {
  }
  
  TcpConnector::TcpConnector(TcpConnector&& other) : dispatcher(other.dispatcher) {
    if (dispatcher != nullptr) {
      assert(other.context == nullptr);
      context = nullptr;
      other.dispatcher = nullptr;
    }
  }
  
  TcpConnector::~TcpConnector() {
    assert(dispatcher == nullptr || context == nullptr);
  }
  
  TcpConnector& TcpConnector::operator=(TcpConnector&& other) {
    assert(dispatcher == nullptr || context == nullptr);
    dispatcher = other.dispatcher;
    if (dispatcher != nullptr) {
      assert(other.context == nullptr);
      context = nullptr;
      other.dispatcher = nullptr;
    }
  
    return *this;
  }
  
  TcpConnection TcpConnector::connect(const Ipv4Address& address, uint16_t port) {
    assert(dispatcher != nullptr);
    assert(context == nullptr);
    if (dispatcher->interrupted()) {
      throw InterruptedException();
    }
  
    std::string message;
    SOCKET connection = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (connection == INVALID_SOCKET) {
      message = "socket failed, " + errorMessage(WSAGetLastError());
    } else {
      sockaddr_in bindAddress;
      bindAddress.sin_family = AF_INET;
      bindAddress.sin_port = 0;
      bindAddress.sin_addr.s_addr = INADDR_ANY;
      if (bind(connection, reinterpret_cast<sockaddr*>(&bindAddress), sizeof bindAddress) != 0) {
        message = "bind failed, " + errorMessage(WSAGetLastError());
      } else {
        GUID guidConnectEx = WSAID_CONNECTEX;
        DWORD read = sizeof connectEx;
        if (connectEx == nullptr && WSAIoctl(connection, SIO_GET_EXTENSION_FUNCTION_POINTER, &guidConnectEx, sizeof guidConnectEx, &connectEx, sizeof connectEx, &read, NULL, NULL) != 0) {
          message = "WSAIoctl failed, " + errorMessage(WSAGetLastError());
        } else {
          assert(read == sizeof connectEx);
          if (CreateIoCompletionPort(reinterpret_cast<HANDLE>(connection), dispatcher->getCompletionPort(), 0, 0) != dispatcher->getCompletionPort()) {
            message = "CreateIoCompletionPort failed, " + lastErrorMessage();
          } else {
            sockaddr_in addressData;
            addressData.sin_family = AF_INET;
            addressData.sin_port = htons(port);
            addressData.sin_addr.S_un.S_addr = htonl(address.getValue());
            TcpConnectorContext context2;
            context2.hEvent = NULL;
            if (connectEx(connection, reinterpret_cast<sockaddr*>(&addressData), sizeof addressData, NULL, 0, NULL, &context2) == TRUE) {
              message = "ConnectEx returned immediately, which is not supported.";
            } else {
              int lastError = WSAGetLastError();
              if (lastError != WSA_IO_PENDING) {
                message = "ConnectEx failed, " + errorMessage(lastError);
              } else {
                context2.context = dispatcher->getCurrentContext();
                context2.connection = connection;
                context2.interrupted = false;
                context = &context2;
                dispatcher->getCurrentContext()->interruptProcedure = [&]() {
                  assert(dispatcher != nullptr);
                  assert(context != nullptr);
                  TcpConnectorContext* context2 = static_cast<TcpConnectorContext*>(context);
                  if (!context2->interrupted) {
                    if (CancelIoEx(reinterpret_cast<HANDLE>(context2->connection), context2) != TRUE) {
                      DWORD lastError = GetLastError();
                      if (lastError != ERROR_NOT_FOUND) {
                        throw std::runtime_error("TcpConnector::stop, CancelIoEx failed, " + lastErrorMessage());
                      }
  
                      context2->context->interrupted = true;
                    }
  
                    context2->interrupted = true;
                  }
                };
  
                dispatcher->dispatch();
                dispatcher->getCurrentContext()->interruptProcedure = nullptr;
                assert(context2.context == dispatcher->getCurrentContext());
                assert(context2.connection == connection);
                assert(dispatcher != nullptr);
                assert(context == &context2);
                context = nullptr;
                DWORD transferred;
                DWORD flags;
                if (WSAGetOverlappedResult(connection, &context2, &transferred, FALSE, &flags) != TRUE) {
                  lastError = WSAGetLastError();
                  if (lastError != ERROR_OPERATION_ABORTED) {
                    message = "ConnectEx failed, " + errorMessage(lastError);
                  } else {
                    assert(context2.interrupted);
                    if (closesocket(connection) != 0) {
                      throw std::runtime_error("TcpConnector::connect, closesocket failed, " + errorMessage(WSAGetLastError()));
                    } else {
                      throw InterruptedException();
                    }
                  }
                } else {
                  assert(transferred == 0);
                  assert(flags == 0);
                  DWORD value = 1;
                  if (setsockopt(connection, SOL_SOCKET, SO_UPDATE_CONNECT_CONTEXT, reinterpret_cast<char*>(&value), sizeof(value)) != 0) {
                    message = "setsockopt failed, " + errorMessage(WSAGetLastError());
                  } else {
                    return TcpConnection(*dispatcher, connection);
                  }
                }
              }
            }
          }
        }
      }
  
      int result = closesocket(connection);
      assert(result == 0);
    }
  
    throw std::runtime_error("TcpConnector::connect, " + message);
  }
  
  }
  