SetSocketKeepAlive for QAbstractSocket

// Includes for SetSocketKeepAlive
#if defined _WINDOWS
 #include <winsock2.h>
 #include <Mstcpip.h>
#else
 #include <sys/socket.h>
 #include <netinet/tcp.h>
#endif


/*!
 * \brief SetSocketKeepAlive
 * KeepAlive mechanism for sockets
 *
 * \param socket
 * \param enable
 * \param idletime
 * \param interval
 *
 * \return bool
 */
bool GlobalServiceData::SetSocketKeepAlive(QAbstractSocket * socket, bool enable /*= true*/, unsigned idletime /*= 5*/, unsigned interval /*= 1*/)
{
 int fd = socket->socketDescriptor();
#if defined _WINDOWS
 // Adopted from: Qt\5.11.2\qtwebengine\src\3rdparty\chromium\net\socket\tcp_socket_win.cc 

 tcp_keepalive keepalive_vals = {
  enable ? 1u : 0u,  // TCP keep-alive on.
  idletime * 1000,  // Delay time before sending first TCP keep-alive packet.
  interval * 1000,  // Delay time between sending TCP keep-alive packets.
 };
 DWORD bytes_returned = 0xABAB;
 int rv = WSAIoctl(fd, SIO_KEEPALIVE_VALS, &keepalive_vals, sizeof(keepalive_vals), NULL, 0, &bytes_returned, NULL, NULL);

 // Disregard any failure in disabling nagle or enabling TCP Keep-Alive.
 return rv == 0;

#else

 // Adopted from: Qt\5.11.2\qtwebengine\src\3rdparty\chromium\net\socket\tcp_socket_posix.cc

 // Enabling TCP keepalives is the same on all platforms.
 int on = enable ? 1 : 0;
 if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on))) { return false; }

 // If we disabled TCP keep alive, our work is done here.
 if (!enable) return true;

 // The following part only applies to OS_LINUX and OS_ANDROID
 // Setting the keepalive interval varies by platform.
 // Set seconds until first TCP keep alive.
 if (setsockopt(fd, SOL_TCP, TCP_KEEPIDLE, &idletime, sizeof(idletime))) { return false; }

 // Set seconds between TCP keep alives.
 if (setsockopt(fd, SOL_TCP, TCP_KEEPINTVL, &interval, sizeof(interval))) { return false; }

 return true;
#endif
}