correctly clean up various things

src/yggdrasil/link.go

@@ -114,7 +114,12 @@ func (intf *linkInterface) handler() error {
 	} else {
 		intf.closed = make(chan struct{})
 		intf.link.interfaces[intf.info] = intf
-		defer close(intf.closed)
+		defer func() {
+			intf.link.mutex.Lock()
+			delete(intf.link.interfaces, intf.info)
+			intf.link.mutex.Unlock()
+			close(intf.closed)
+		}()
 		intf.link.core.log.Println("DEBUG: registered interface for", intf.name)
 	}
 	intf.link.mutex.Unlock()
@@ -144,7 +149,10 @@ func (intf *linkInterface) handler() error {
 		timer := time.NewTimer(interval)
 		clearTimer := func() {
 			if !timer.Stop() {
-				<-timer.C
+				select {
+				case <-timer.C:
+				default:
+				}
 			}
 		}
 		defer clearTimer()

src/yggdrasil/tcp.go

@@ -294,8 +294,8 @@ func (iface *tcpInterface) handler(sock net.Conn, incoming bool) {
 		panic(err)
 	}
 	iface.core.log.Println("DEBUG: starting handler for", name)
-	link.handler()
-	iface.core.log.Println("DEBUG: stopped handler for", name)
+	err = link.handler()
+	iface.core.log.Println("DEBUG: stopped handler for", name, err)
 }
 
 // This exchanges/checks connection metadata, sets up the peer struct, sets up the writer goroutine, and then runs the reader within the current goroutine.