Function CreateTUNFromFile

polyamide/tun/tun_linux.go:585–633

CreateTUNFromFile creates a Device from an os.File with the provided MTU.

(file *os.File, mtu int)

// CreateTUNFromFile creates a Device from an os.File with the provided MTU.
func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
	tun := &NativeTun{
		tunFile:                 file,
		events:                  make(chan Event, 5),
		errors:                  make(chan error, 5),
		statusListenersShutdown: make(chan struct{}),
		tcpGROTable:             newTCPGROTable(),
		udpGROTable:             newUDPGROTable(),
		toWrite:                 make([]int, 0, conn.IdealBatchSize),
	}

	name, err := tun.Name()
	if err != nil {
		return nil, err
	}

	err = tun.initFromFlags(name)
	if err != nil {
		return nil, err
	}

	// start event listener
	tun.index, err = getIFIndex(name)
	if err != nil {
		return nil, err
	}

	tun.netlinkSock, err = createNetlinkSocket()
	if err != nil {
		return nil, err
	}
	tun.netlinkCancel, err = rwcancel.NewRWCancel(tun.netlinkSock)
	if err != nil {
		unix.Close(tun.netlinkSock)
		return nil, err
	}

	tun.hackListenerClosed.Lock()
	go tun.routineNetlinkListener()
	go tun.routineHackListener() // cross namespace

	err = tun.setMTU(mtu)
	if err != nil {
		unix.Close(tun.netlinkSock)
		return nil, err
	}

	return tun, nil
}

// CreateUnmonitoredTUNFromFD creates a Device from the provided file
// descriptor.