Stop counting handlers before terminating.

The requirement to do so is obsolete and has already been removed from
other pluggable transports.

https://bugs.torproject.org/32046

server-webrtc/snowflake.go

@@ -21,10 +21,6 @@ var ptMethodName = "snowflake"
 var ptInfo pt.ServerInfo
 var logFile *os.File
 
-// When a datachannel handler starts, +1 is written to this channel;
-// when it ends, -1 is written.
-var handlerChan = make(chan int)
-
 func copyLoop(WebRTC, ORPort net.Conn) {
 	var wg sync.WaitGroup
 	wg.Add(2)
@@ -100,11 +96,6 @@ func (c *webRTCConn) SetWriteDeadline(t time.Time) error {
 func datachannelHandler(conn *webRTCConn) {
 	defer conn.Close()
 
-	handlerChan <- 1
-	defer func() {
-		handlerChan <- -1
-	}()
-
 	or, err := pt.DialOr(&ptInfo, "", ptMethodName) // TODO: Extended OR
 	if err != nil {
 		log.Printf("Failed to connect to ORPort: " + err.Error())
@@ -246,8 +237,6 @@ func main() {
 	}
 	pt.SmethodsDone()
 
-	var numHandlers int
-	var sig os.Signal
 	sigChan := make(chan os.Signal, 1)
 	signal.Notify(sigChan, syscall.SIGTERM)
 
@@ -263,17 +252,6 @@ func main() {
 		}()
 	}
 
-	// keep track of handlers and wait for a signal
-	sig = nil
-	for sig == nil {
-		select {
-		case n := <-handlerChan:
-			numHandlers += n
-		case sig = <-sigChan:
-		}
-	}
-
-	for numHandlers > 0 {
-		numHandlers += <-handlerChan
-	}
+	// wait for a signal
+	<-sigChan
 }