all: make router setup/cleanup works more generally

cmd/ctrld/cli.go

@@ -275,22 +275,19 @@ func initCLI() {
 				if cp := router.CertPool(); cp != nil {
 					rootCertPool = cp
 				}
-				// Perform router setup/cleanup if ctrld could not be direct listener.
-				if !couldBeDirectListener(cfg.FirstListener()) {
-					p.onStarted = append(p.onStarted, func() {
-						mainLog.Debug().Msg("router setup")
-						if err := p.router.Setup(); err != nil {
-							mainLog.Error().Err(err).Msg("could not configure router")
-						}
-					})
-					p.onStopped = append(p.onStopped, func() {
-						mainLog.Debug().Msg("router cleanup")
-						if err := p.router.Cleanup(); err != nil {
-							mainLog.Error().Err(err).Msg("could not cleanup router")
-						}
-						p.resetDNS()
-					})
-				}
+				p.onStarted = append(p.onStarted, func() {
+					mainLog.Debug().Msg("router setup")
+					if err := p.router.Setup(); err != nil {
+						mainLog.Error().Err(err).Msg("could not configure router")
+					}
+				})
+				p.onStopped = append(p.onStopped, func() {
+					mainLog.Debug().Msg("router cleanup")
+					if err := p.router.Cleanup(); err != nil {
+						mainLog.Error().Err(err).Msg("could not cleanup router")
+					}
+					p.resetDNS()
+				})
 			}
 
 			close(waitCh)
@@ -404,7 +401,7 @@ func initCLI() {
 				return
 			}
 
-			if router.Name() != "" && !couldBeDirectListener(cfg.FirstListener()) {
+			if router.Name() != "" {
 				mainLog.Debug().Msg("cleaning up router before installing")
 				_ = p.router.Cleanup()
 			}
@@ -504,15 +501,18 @@ func initCLI() {
 		Short: "Stop the ctrld service",
 		Args:  cobra.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			prog := &prog{}
-			s, err := newService(prog, svcConfig)
+			tryReadingConfig(false)
+			v.Unmarshal(&cfg)
+			p := &prog{router: router.New(&cfg)}
+			s, err := newService(p, svcConfig)
 			if err != nil {
 				mainLog.Error().Msg(err.Error())
 				return
 			}
 			initLogging()
 			if doTasks([]task{{s.Stop, true}}) {
-				prog.resetDNS()
+				p.router.Cleanup()
+				p.resetDNS()
 				mainLog.Notice().Msg("Service stopped")
 			}
 		},
@@ -591,7 +591,9 @@ func initCLI() {
 NOTE: Uninstalling will set DNS to values provided by DHCP.`,
 		Args: cobra.NoArgs,
 		Run: func(cmd *cobra.Command, args []string) {
-			p := &prog{}
+			tryReadingConfig(false)
+			v.Unmarshal(&cfg)
+			p := &prog{router: router.New(&cfg)}
 			s, err := newService(p, svcConfig)
 			if err != nil {
 				mainLog.Error().Msg(err.Error())
@@ -1157,19 +1159,20 @@ func uninstall(p *prog, s service.Service) {
 	}
 	initLogging()
 	if doTasks(tasks) {
-		r := router.New(&cfg)
-		if err := r.Uninstall(svcConfig); err != nil {
+		if err := p.router.ConfigureService(svcConfig); err != nil {
+			mainLog.Fatal().Err(err).Msg("could not configure service")
+		}
+		if err := p.router.Uninstall(svcConfig); err != nil {
 			mainLog.Warn().Err(err).Msg("post uninstallation failed, please check system/service log for details error")
 			return
 		}
-		// Stop already reset DNS on router.
-		if router.Name() == "" {
-			p.resetDNS()
+		p.resetDNS()
+		if router.Name() != "" {
+			mainLog.Debug().Msg("Router cleanup")
 		}
-		mainLog.Debug().Msg("Router cleanup")
 		// Stop already did router.Cleanup and report any error if happens,
 		// ignoring error here to prevent false positive.
-		_ = r.Cleanup()
+		_ = p.router.Cleanup()
 		mainLog.Notice().Msg("Service uninstalled")
 		return
 	}

cmd/ctrld/os_linux.go

@@ -147,7 +147,7 @@ func resetDNS(iface *net.Interface) (err error) {
 	if ctrldnet.IPv6Available(ctx) {
 		c := client6.NewClient()
 		conversation, err := c.Exchange(iface.Name)
-		if err != nil {
+		if err != nil && !errAddrInUse(err) {
 			mainLog.Debug().Err(err).Msg("could not exchange DHCPv6")
 		}
 		for _, packet := range conversation {

cmd/ctrld/prog.go

@@ -1,12 +1,14 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"math/rand"
 	"net"
 	"os"
 	"strconv"
 	"sync"
+	"syscall"
 
 	"github.com/kardianos/service"
 
@@ -216,7 +218,7 @@ func (p *prog) setDNS() {
 	logger.Debug().Msg("setting DNS for interface")
 	ns := lc.IP
 	switch {
-	case couldBeDirectListener(lc):
+	case lc.IsDirectDnsListener():
 		// If ctrld is direct listener, use 127.0.0.1 as nameserver.
 		ns = "127.0.0.1"
 	case lc.Port != 53:
@@ -294,3 +296,11 @@ func runLogServer(sockPath string) net.Conn {
 	}
 	return server
 }
+
+func errAddrInUse(err error) bool {
+	opErr, ok := err.(*net.OpError)
+	if !ok {
+		return false
+	}
+	return errors.Is(opErr.Err, syscall.EADDRINUSE)
+}