Close idle connections of unreferenced outbounds and DNS servers

protocol/group/selector.go

@@ -25,6 +25,7 @@ func RegisterSelector(registry *outbound.Registry) {
 
 var (
 	_ adapter.OutboundGroup           = (*Selector)(nil)
+	_ adapter.Referrer                = (*Selector)(nil)
 	_ adapter.ConnectionHandler       = (*Selector)(nil)
 	_ adapter.PacketConnectionHandler = (*Selector)(nil)
 )
@@ -120,6 +121,10 @@ func (s *Selector) All() []string {
 	return s.tags
 }
 
+func (s *Selector) References() []string {
+	return []string{s.Now()}
+}
+
 func (s *Selector) SelectOutbound(tag string) bool {
 	detour, loaded := s.outbounds[tag]
 	if !loaded {

protocol/group/urltest.go

@@ -32,6 +32,7 @@ func RegisterURLTest(registry *outbound.Registry) {
 var (
 	_ adapter.OutboundGroup           = (*URLTest)(nil)
 	_ adapter.InterfaceUpdateListener = (*URLTest)(nil)
+	_ adapter.Referrer                = (*URLTest)(nil)
 )
 
 type URLTest struct {
@@ -111,6 +112,21 @@ func (s *URLTest) All() []string {
 	return s.tags
 }
 
+func (s *URLTest) References() []string {
+	group := s.group
+	if group == nil {
+		return nil
+	}
+	var references []string
+	if group.selectedOutboundTCP != nil {
+		references = append(references, group.selectedOutboundTCP.Tag())
+	}
+	if group.selectedOutboundUDP != nil && group.selectedOutboundUDP != group.selectedOutboundTCP {
+		references = append(references, group.selectedOutboundUDP.Tag())
+	}
+	return references
+}
+
 func (s *URLTest) URLTest(ctx context.Context) (map[string]uint16, error) {
 	return s.group.URLTest(ctx)
 }
@@ -488,20 +504,28 @@ func (b *urlTestBatch) test(outbounds []adapter.Outbound, link string, interval
 func (g *URLTestGroup) performUpdateCheck() {
 	g.updateAccess.Lock()
 	defer g.updateAccess.Unlock()
-	var updated bool
+	var (
+		updated  bool
+		selected bool
+	)
 	if outbound, exists := g.Select(N.NetworkTCP); outbound != nil && (g.selectedOutboundTCP == nil || (exists && outbound != g.selectedOutboundTCP)) {
 		if g.selectedOutboundTCP != nil {
 			updated = true
 		}
 		g.selectedOutboundTCP = outbound
+		selected = true
 	}
 	if outbound, exists := g.Select(N.NetworkUDP); outbound != nil && (g.selectedOutboundUDP == nil || (exists && outbound != g.selectedOutboundUDP)) {
 		if g.selectedOutboundUDP != nil {
 			updated = true
 		}
 		g.selectedOutboundUDP = outbound
+		selected = true
 	}
 	if updated {
 		g.interruptGroup.Interrupt(g.interruptExternalConnections)
 	}
+	if selected {
+		g.history.NotifyUpdated()
+	}
 }