-
Notifications
You must be signed in to change notification settings - Fork 18
/
tun.go
107 lines (81 loc) · 1.84 KB
/
tun.go
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
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
package meshboi
import (
"io"
"os"
"os/exec"
"strconv"
"syscall"
"unsafe"
)
const (
IFF_TUN = 0x1 /* Flag to open a TUN device (rather than TAP) */
IFF_NO_PI = 0x1000 /* Do not provide packet information */
)
type ifReq struct {
Name [16]byte
Flags uint16
}
type Tun struct {
io.ReadWriteCloser
Name string
}
type TunConn interface {
io.ReadWriteCloser
}
//https://www.kernel.org/doc/Documentation/networking/tuntap.txt
func NewTun(name string) (*Tun, error) {
tunFile, err := os.OpenFile("/dev/net/tun", os.O_RDWR, 0)
if err != nil {
return nil, err
}
req := ifReq{}
req.Flags = IFF_TUN | IFF_NO_PI
copy(req.Name[:], name)
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, tunFile.Fd(), syscall.TUNSETIFF, uintptr(unsafe.Pointer(&req)))
if errno != 0 {
return nil, os.NewSyscallError("ioctl", errno)
}
tun := Tun{
Name: name,
ReadWriteCloser: tunFile,
}
return &tun, nil
}
// Makes a Tun with the desired config and immediately sets it up
func NewTunWithConfig(name string, ip string, mtu int) (*Tun, error) {
tun, err := NewTun(name)
if err != nil {
return nil, err
}
if err := tun.SetNetwork(ip); err != nil {
return nil, err
}
if err := tun.SetMtu(mtu); err != nil {
return nil, err
}
if err := tun.SetLinkUp(); err != nil {
return nil, err
}
return tun, nil
}
func (t Tun) SetLinkUp() error {
cmd := exec.Command("/sbin/ip", "link", "set", t.Name, "up")
if err := cmd.Run(); err != nil {
return err
}
return nil
}
func (t Tun) SetNetwork(ip string) error {
cmd := exec.Command("/sbin/ip", "addr", "add", ip, "dev", t.Name)
if err := cmd.Run(); err != nil {
return err
}
return nil
}
func (t Tun) SetMtu(mtu int) error {
cmd := exec.Command("/sbin/ip", "link", "set", "dev", t.Name, "mtu", strconv.Itoa(mtu))
if err := cmd.Run(); err != nil {
return err
}
return nil
}