From cd9396993057ba25ef904a890f2e01e5b73b1286 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Thu, 24 Oct 2019 23:37:39 +0100
Subject: [PATCH] Fix isOpen for TUN/TAP actor

---
 src/tuntap/tun.go | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/tuntap/tun.go b/src/tuntap/tun.go
index 06feede..f0250c9 100644
--- a/src/tuntap/tun.go
+++ b/src/tuntap/tun.go
@@ -143,9 +143,12 @@ func (tun *TunAdapter) Start() error {
 }
 
 func (tun *TunAdapter) _start() error {
+	if tun.isOpen {
+		return errors.New("TUN/TAP module is already started")
+	}
 	current := tun.config.GetCurrent()
 	if tun.config == nil || tun.listener == nil || tun.dialer == nil {
-		return errors.New("No configuration available to TUN/TAP")
+		return errors.New("no configuration available to TUN/TAP")
 	}
 	var boxPub crypto.BoxPubKey
 	boxPubHex, err := hex.DecodeString(current.EncryptionPublicKey)
@@ -182,7 +185,11 @@ func (tun *TunAdapter) _start() error {
 
 // IsStarted returns true if the module has been started.
 func (tun *TunAdapter) IsStarted() bool {
-	return tun.isOpen
+	var isOpen bool
+	phony.Block(tun, func() {
+		isOpen = tun.isOpen
+	})
+	return isOpen
 }
 
 // Start the setup process for the TUN/TAP adapter. If successful, starts the