From 426d1570259dedec8d527b8c832b24b4829d4765 Mon Sep 17 00:00:00 2001
From: Arceliar <Arceliar@users.noreply.github.com>
Date: Fri, 8 Mar 2019 18:51:07 -0600
Subject: [PATCH] make sure we don't replace an existing listener

---
 src/yggdrasil/tcp.go | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/yggdrasil/tcp.go b/src/yggdrasil/tcp.go
index 2a177c03..43ea4431 100644
--- a/src/yggdrasil/tcp.go
+++ b/src/yggdrasil/tcp.go
@@ -155,8 +155,14 @@ func (t *tcp) listener(l *tcpListener, listenaddr string) {
 	}
 	// Track the listener so that we can find it again in future
 	t.mutex.Lock()
-	t.listeners[listenaddr] = l
-	t.mutex.Unlock()
+	if _, isIn := t.listeners[listenaddr]; isIn {
+		t.mutex.Unlock()
+		l.listener.Close()
+		return
+	} else {
+		t.listeners[listenaddr] = l
+		t.mutex.Unlock()
+	}
 	// And here we go!
 	accepted := make(chan bool)
 	defer func() {