add rate measure

tunnel/link.go

@@ -32,9 +32,12 @@ type link struct {
 	// channels keeps a mapping of channels and last seen
 	channels map[string]time.Time
 
-	// the weighed moving average roundtrip
+	// the weighted moving average roundtrip
 	rtt int64
 
+	// weighted moving average of bits flowing
+	rate float64
+
 	// keep an error count on the link
 	errCount int
 }
@@ -55,7 +58,7 @@ func (l *link) setRTT(d time.Duration) {
 	l.Lock()
 	defer l.Unlock()
 
-	if l.rtt < 0 {
+	if l.rtt <= 0 {
 		l.rtt = d.Nanoseconds()
 		return
 	}
@@ -110,7 +113,9 @@ func (l *link) Delay() int64 {
 
 // Current transfer rate as bits per second (lower is better)
 func (l *link) Rate() float64 {
-	return float64(10e8)
+	l.RLock()
+	defer l.RUnlock()
+	return l.rate
 }
 
 // Length returns the roundtrip time as nanoseconds (lower is better).
@@ -141,11 +146,43 @@ func (l *link) Close() error {
 }
 
 func (l *link) Send(m *transport.Message) error {
+	dataSent := len(m.Body)
+
+	// set header length
+	for k, v := range m.Header {
+		dataSent += (len(k) + len(v))
+	}
+
+	// get time now
+	now := time.Now()
+
+	// send the message
 	err := l.Socket.Send(m)
 
 	l.Lock()
 	defer l.Unlock()
 
+	// calculate based on data
+	if dataSent > 0 {
+		// measure time taken
+		delta := time.Since(now)
+
+		// bit sent
+		bits := dataSent * 1024
+
+		// rate of send in bits per nanosecond
+		rate := float64(bits) / float64(delta.Nanoseconds())
+
+		//
+		if l.rate == 0 {
+			// rate per second
+			l.rate = rate * 1e9
+		} else {
+			// set new rate per second
+			l.rate = 0.8*l.rate + 0.2*(rate*1e9)
+		}
+	}
+
 	// if theres no error reset the counter
 	if err == nil {
 		l.errCount = 0