func main() {
log.Println("Multicast discovery utility running...")
mc := multicast.JoinMulticast(func(peer string, peers []multicast.PeerInfo) {
log.Println("Added new peer:", peer)
},
func(peer string, peers []multicast.PeerInfo) {
log.Println("Removed peer:", peer)
})
/*
f, err := mc.conn.File()
err = syscall.SetsockoptInt(int(f.Fd()), syscall.IPPROTO_IP, syscall.IP_MULTICAST_LOOP, 1)
if err != nil {
log.Fatal("Error setting up socket for multicast loop")
}
*/
mc.SetPeriod(1)
mc.StartMulticast()
mc.ListenPeers()
c := make(chan os.Signal, 1)
signal.Notify(c, os.Interrupt)
go func() {
<-c
log.Println("Leaving multicast group...")
mc.LeaveMulticast()
log.Println("Quitting multicast discovery...")
os.Exit(0)
}()
// Sleep forever in main goroutine
select {}
}
// Start begins the local Lantern discovery process
func Start(advertise bool, portToAdvertise string) {
if service != nil {
// Dev error: this service shouldn't be started unless stopped
panic("The " + messageType + " service is already registered")
return
}
var err error
service, err = ui.Register(messageType, nil, func(write func(interface{}) error) error {
// When connecting the UI we push the current peer list. For this reason, we need
// to hold this list beyond the add/remove events.
return write(buildPeersList())
})
if err != nil {
log.Errorf("Unable to register Local Discovery service: %q", err)
return
}
addOrRemoveCb := func(peer string, peersInfo []multicast.PeerInfo) {
peersMutex.Lock()
lastPeers = peersInfo
peersMutex.Unlock()
service.Out <- buildPeersList()
}
mc = multicast.JoinMulticast(addOrRemoveCb, addOrRemoveCb)
if advertise {
mc.SetPayload(portToAdvertise)
mc.StartMulticast()
}
mc.ListenPeers()
}