366cbd11a4
The new sysconn function of Go 1.12 makes this possible:
package main
import "log"
import "os"
import "unsafe"
import "time"
import "syscall"
import "sync"
import "golang.org/x/sys/unix"
func main() {
fd, err := os.OpenFile("/dev/net/tun", os.O_RDWR, 0)
if err != nil {
log.Fatal(err)
}
var ifr [unix.IFNAMSIZ + 64]byte
copy(ifr[:], []byte("cheese"))
*(*uint16)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])) = unix.IFF_TUN
var errno syscall.Errno
s, _ := fd.SyscallConn()
s.Control(func(fd uintptr) {
_, _, errno = unix.Syscall(
unix.SYS_IOCTL,
fd,
uintptr(unix.TUNSETIFF),
uintptr(unsafe.Pointer(&ifr[0])),
)
})
if errno != 0 {
log.Fatal(errno)
}
b := [4]byte{}
wait := sync.WaitGroup{}
wait.Add(1)
go func() {
_, err := fd.Read(b[:])
log.Print("Read errored: ", err)
wait.Done()
}()
time.Sleep(time.Second)
log.Print("Closing")
err = fd.Close()
if err != nil {
log.Print("Close errored: " , err)
}
wait.Wait()
log.Print("Exiting")
}
42 lines
1.2 KiB
Go
42 lines
1.2 KiB
Go
/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
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*/
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package tun
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import (
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"fmt"
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"os"
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)
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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 (tun *nativeTun) operateOnFd(fn func(fd uintptr)) {
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sysconn, err := tun.tunFile.SyscallConn()
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if err != nil {
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tun.errors <- fmt.Errorf("unable to find sysconn for tunfile: %s", err.Error())
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return
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}
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err = sysconn.Control(fn)
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if err != nil {
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tun.errors <- fmt.Errorf("unable to control sysconn for tunfile: %s", err.Error())
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}
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}
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