From 26a56a652eeeece7677ba4f1896da34c83930652 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Wed, 18 Apr 2018 16:39:14 +0200
Subject: [PATCH] Allow determining name
---
device.go | 8 ++++++++
tun.go | 2 +-
tun_linux.go | 25 +++++++++++++++++++------
3 files changed, 28 insertions(+), 7 deletions(-)
diff --git a/device.go b/device.go
index 79ec0b8..5adf33a 100644
--- a/device.go
+++ b/device.go
@@ -255,7 +255,15 @@ func NewDevice(tun TUNDevice, logger *Logger) *Device {
device.isClosed.Set(false)
device.log = logger
+
device.tun.device = tun
+ mtu, err := device.tun.device.MTU()
+ if err != nil {
+ logger.Error.Println("Trouble determining MTU, assuming 1420:", err)
+ mtu = 1420
+ }
+ device.tun.mtu = int32(mtu)
+
device.peers.keyMap = make(map[NoisePublicKey]*Peer)
// initialize anti-DoS / anti-scanning features
diff --git a/tun.go b/tun.go
index 7b044ad..318772a 100644
--- a/tun.go
+++ b/tun.go
@@ -20,7 +20,7 @@ type TUNDevice interface {
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
+ Name() (string, error) // fetches and 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
}
diff --git a/tun_linux.go b/tun_linux.go
index da53907..06b5af4 100644
--- a/tun_linux.go
+++ b/tun_linux.go
@@ -11,6 +11,7 @@ import (
"golang.org/x/sys/unix"
"net"
"os"
+ "strconv"
"strings"
"time"
"unsafe"
@@ -130,10 +131,6 @@ func (tun *NativeTun) isUp() (bool, error) {
return inter.Flags&net.FlagUp != 0, err
}
-func (tun *NativeTun) Name() string {
- return tun.name
-}
-
func getDummySock() (int, error) {
return unix.Socket(
unix.AF_INET,
@@ -229,7 +226,7 @@ func (tun *NativeTun) MTU() (int, error) {
uintptr(unsafe.Pointer(&ifr[0])),
)
if errno != 0 {
- return 0, errors.New("Failed to get MTU of TUN device")
+ return 0, errors.New("Failed to get MTU of TUN device: " + strconv.FormatInt(int64(errno), 10))
}
// convert result to signed 32-bit int
@@ -241,6 +238,22 @@ func (tun *NativeTun) MTU() (int, error) {
return int(val), nil
}
+func (tun *NativeTun) Name() (string, error) {
+
+ var ifr [ifReqSize]byte
+ _, _, errno := unix.Syscall(
+ unix.SYS_IOCTL,
+ tun.fd.Fd(),
+ uintptr(unix.TUNGETIFF),
+ uintptr(unsafe.Pointer(&ifr[0])),
+ )
+ if errno != 0 {
+ return "", errors.New("Failed to get name of TUN device: " + strconv.FormatInt(int64(errno), 10))
+ }
+ tun.name = string(ifr[:])
+ return tun.name, nil
+}
+
func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
if tun.nopi {
@@ -342,7 +355,7 @@ func CreateTUN(name string) (TUNDevice, error) {
_, _, errno := unix.Syscall(
unix.SYS_IOCTL,
- uintptr(fd.Fd()),
+ fd.Fd(),
uintptr(unix.TUNSETIFF),
uintptr(unsafe.Pointer(&ifr[0])),
)