67 lines
1.7 KiB
Go
67 lines
1.7 KiB
Go
/* SPDX-License-Identifier: GPL-2.0
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*
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* Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*/
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package main
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import (
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"os"
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"sync/atomic"
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)
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const DefaultMTU = 1420
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type TUNEvent int
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const (
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TUNEventUp = 1 << iota
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TUNEventDown
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TUNEventMTUUpdate
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)
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type TUNDevice interface {
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File() *os.File // returns the file descriptor of the device
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Read([]byte, int) (int, error) // read a packet from the device (without any additional headers)
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Write([]byte, int) (int, error) // writes a packet to the device (without any additional headers)
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MTU() (int, error) // returns the MTU of the device
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Name() (string, error) // fetches and returns the current name
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Events() chan TUNEvent // returns a constant channel of events related to the device
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Close() error // stops the device and closes the event channel
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}
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func (device *Device) RoutineTUNEventReader() {
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setUp := false
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logInfo := device.log.Info
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logError := device.log.Error
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for event := range device.tun.device.Events() {
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if event&TUNEventMTUUpdate != 0 {
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mtu, err := device.tun.device.MTU()
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old := atomic.LoadInt32(&device.tun.mtu)
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if err != nil {
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logError.Println("Failed to load updated MTU of device:", err)
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} else if int(old) != mtu {
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if mtu+MessageTransportSize > MaxMessageSize {
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logInfo.Println("MTU updated:", mtu, "(too large)")
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} else {
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logInfo.Println("MTU updated:", mtu)
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}
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atomic.StoreInt32(&device.tun.mtu, int32(mtu))
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}
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}
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if event&TUNEventUp != 0 && !setUp {
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logInfo.Println("Interface set up")
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setUp = true
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device.Up()
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}
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if event&TUNEventDown != 0 && setUp {
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logInfo.Println("Interface set down")
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setUp = false
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device.Down()
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}
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}
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}
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