1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
// Copyright 2018 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package tun contains methods to open TAP and TUN devices.
package tun
import (
"syscall"
"unsafe"
)
// Open opens the specified TUN device, sets it to non-blocking mode, and
// returns its file descriptor.
func Open(name string) (int, error) {
return open(name, syscall.IFF_TUN|syscall.IFF_NO_PI)
}
// OpenTAP opens the specified TAP device, sets it to non-blocking mode, and
// returns its file descriptor.
func OpenTAP(name string) (int, error) {
return open(name, syscall.IFF_TAP|syscall.IFF_NO_PI)
}
func open(name string, flags uint16) (int, error) {
fd, err := syscall.Open("/dev/net/tun", syscall.O_RDWR, 0)
if err != nil {
return -1, err
}
var ifr struct {
name [16]byte
flags uint16
_ [22]byte
}
copy(ifr.name[:], name)
ifr.flags = flags
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd), syscall.TUNSETIFF, uintptr(unsafe.Pointer(&ifr)))
if errno != 0 {
syscall.Close(fd)
return -1, errno
}
if err = syscall.SetNonblock(fd, true); err != nil {
syscall.Close(fd)
return -1, err
}
return fd, nil
}
|
