package main import ( "git.zx2c4.com/wireguard-go/internal/events" "os" "sync/atomic" ) const DefaultMTU = 1420 const ( TUNEventUp = 1 << iota TUNEventDown TUNEventMTUUpdate ) type TUNDevice interface { File() *os.File // returns the file descriptor of the device Read([]byte, int) (int, error) // read a packet from the device (without any additional headers) Write([]byte, int) (int, error) // writes a packet to the device (without any additional headers) MTU() (int, error) // returns the MTU of the device Name() string // returns the current name Events() chan events.Event // returns a constant channel of events related to the device Close() error // stops the device and closes the event channel } func (device *Device) RoutineTUNEventReader() { logInfo := device.log.Info logError := device.log.Error for event := range device.tun.device.Events() { if event.Contains(TUNEventMTUUpdate) { mtu, err := device.tun.device.MTU() old := atomic.LoadInt32(&device.tun.mtu) if err != nil { logError.Println("Failed to load updated MTU of device:", err) } else if int(old) != mtu { if mtu+MessageTransportSize > MaxMessageSize { logInfo.Println("MTU updated:", mtu, "(too large)") } else { logInfo.Println("MTU updated:", mtu) } atomic.StoreInt32(&device.tun.mtu, int32(mtu)) } } if event.Contains(TUNEventUp) && !device.isUp.Get() { logInfo.Println("Interface set up") device.Up() } if event.Contains(TUNEventDown) && device.isUp.Get() { logInfo.Println("Interface set down") device.Down() } event.Processed() } }