cmd/ctrld: fix reset DNS when uninstalling

The "--iface" needs to be explicitly passed, otherwise, ctrld does not
know which interface to restore.

cmd/ctrld/cli.go

@@ -323,11 +323,13 @@ func initCLI() {
 			}
 			initLogging()
 			if doTasks(tasks) {
+				prog.resetDNS()
 				mainLog.Info().Msg("Service uninstalled")
 				return
 			}
 		},
 	}
+	uninstallCmd.Flags().StringVarP(&iface, "iface", "", "auto", `Reset DNS setting for iface, "auto" means the default interface gateway`)
 
 	listIfacesCmd := &cobra.Command{
 		Use:   "list",

cmd/ctrld/os_linux.go

@@ -72,9 +72,10 @@ func setDNS(iface *net.Interface, nameservers []string) error {
 		}
 		currentNS := currentDNS(iface)
 		if reflect.DeepEqual(currentNS, nameservers) {
-			break
+			return nil
 		}
 	}
+	mainLog.Debug().Msg("DNS was not set for some reason")
 	return nil
 }
 
@@ -105,7 +106,6 @@ func resetDNS(iface *net.Interface) error {
 		conversation, err := c.Exchange(iface.Name)
 		if err != nil {
 			mainLog.Debug().Err(err).Msg("could not exchange DHCPv6")
-			return nil
 		}
 		for _, packet := range conversation {
 			if packet.Type() == dhcpv6.MessageTypeReply {

cmd/ctrld/prog.go

@@ -174,11 +174,6 @@ func (p *prog) Stop(s service.Service) error {
 	return nil
 }
 
-func (p *prog) Uninstall(s service.Service) error {
-	p.resetDNS()
-	return nil
-}
-
 func (p *prog) allocateIP(ip string) error {
 	if !p.cfg.Service.AllocateIP {
 		return nil