From a0f54cbe5ac2cd8b8296c2c57c30029dd349cff0 Mon Sep 17 00:00:00 2001 From: Mathias Hall-Andersen Date: Sun, 4 Feb 2018 16:08:26 +0100 Subject: Align with go library layout --- tun.go | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 tun.go (limited to 'tun.go') diff --git a/tun.go b/tun.go new file mode 100644 index 0000000..6259f33 --- /dev/null +++ b/tun.go @@ -0,0 +1,58 @@ +package main + +import ( + "os" + "sync/atomic" +) + +const DefaultMTU = 1420 + +type TUNEvent int + +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 TUNEvent // 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&TUNEventMTUUpdate != 0 { + 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&TUNEventUp != 0 && !device.isUp.Get() { + logInfo.Println("Interface set up") + device.Up() + } + + if event&TUNEventDown != 0 && device.isUp.Get() { + logInfo.Println("Interface set down") + device.Down() + } + } +} -- cgit v1.2.3-59-g8ed1b