Allow multicast to be shut down more sanely

src/multicast/multicast.go

@@ -27,6 +27,8 @@ type Multicast struct {
 	listeners       map[string]*yggdrasil.TcpListener
 	listenPort      uint16
 	isOpen          bool
+	announcer       *time.Timer
+	platformhandler *time.Timer
 }
 
 // Init prepares the multicast interface for use.
@@ -63,9 +65,9 @@ func (m *Multicast) Start() error {
 	}
 
 	m.isOpen = true
-	go m.multicastStarted()
 	go m.listen()
-	go m.announce()
+	m.multicastStarted()
+	m.announce()
 
 	return nil
 }
@@ -73,6 +75,8 @@ func (m *Multicast) Start() error {
 // Stop is not implemented for multicast yet.
 func (m *Multicast) Stop() error {
 	m.isOpen = false
+	m.announcer.Stop()
+	m.platformhandler.Stop()
 	m.sock.Close()
 	return nil
 }
@@ -136,7 +140,6 @@ func (m *Multicast) announce() {
 	if err != nil {
 		panic(err)
 	}
-	for {
 	interfaces := m.Interfaces()
 	// There might be interfaces that we configured listeners for but are no
 	// longer up - if that's the case then we should stop the listeners
@@ -236,8 +239,7 @@ func (m *Multicast) announce() {
 			break
 		}
 	}
-		time.Sleep(time.Second * 15)
-	}
+	m.announcer = time.AfterFunc(time.Second*15, m.announce)
 }
 
 func (m *Multicast) listen() {

src/multicast/multicast_darwin.go

@@ -32,21 +32,14 @@ import (
 var awdlGoroutineStarted bool
 
 func (m *Multicast) multicastStarted() {
-	if awdlGoroutineStarted {
-		return
-	}
-	awdlGoroutineStarted = true
-	for {
 	C.StopAWDLBrowsing()
 	for intf := range m.Interfaces() {
 		if intf == "awdl0" {
-				m.log.Infoln("Multicast discovery is using AWDL discovery")
 			C.StartAWDLBrowsing()
 			break
 		}
 	}
-		time.Sleep(time.Minute)
-	}
+	m.platformhandler = time.AfterFunc(time.Minute, m.multicastStarted)
 }
 
 func (m *Multicast) multicastReuse(network string, address string, c syscall.RawConn) error {