Merge pull request #51 from Control-D-Inc/release-branch-v1.2.1

Release branch v1.2.1

cmd/ctrld/cli.go

@@ -36,8 +36,6 @@ import (
 	"github.com/Control-D-Inc/ctrld/internal/router"
 )
 
-const selfCheckFQDN = "verify.controld.com"
-
 var (
 	version = "dev"
 	commit  = "none"
@@ -138,16 +136,7 @@ func initCLI() {
 						mainLog.Fatal().Err(err).Msg("failed create new service")
 					}
 					s = newService(s)
-					serviceLogger, err := s.Logger(nil)
-					if err != nil {
-						mainLog.Error().Err(err).Msg("failed to get service logger")
-						return
-					}
-
 					if err := s.Run(); err != nil {
-						if sErr := serviceLogger.Error(err); sErr != nil {
-							mainLog.Error().Err(sErr).Msg("failed to write service log")
-						}
 						mainLog.Error().Err(err).Msg("failed to start service")
 					}
 				}()
@@ -176,9 +165,13 @@ func initCLI() {
 			initLogging()
 
 			if setupRouter {
-				if err := router.PreStart(); err != nil {
+				s, errCh := runDNSServerForNTPD(router.ListenAddress())
+				if err := router.PreRun(); err != nil {
 					mainLog.Fatal().Err(err).Msg("failed to perform router pre-start check")
 				}
+				if err := s.Shutdown(); err != nil && errCh != nil {
+					mainLog.Fatal().Err(err).Msg("failed to shutdown dns server for ntpd")
+				}
 			}
 
 			processCDFlags()
@@ -241,6 +234,8 @@ func initCLI() {
 	runCmd.Flags().StringVarP(&logPath, "log", "", "", "Path to log file")
 	runCmd.Flags().IntVarP(&cacheSize, "cache_size", "", 0, "Enable cache with size items")
 	runCmd.Flags().StringVarP(&cdUID, "cd", "", "", "Control D resolver uid")
+	runCmd.Flags().BoolVarP(&cdDev, "dev", "", false, "Use Control D dev resolver/domain")
+	_ = runCmd.Flags().MarkHidden("dev")
 	runCmd.Flags().StringVarP(&homedir, "homedir", "", "", "")
 	_ = runCmd.Flags().MarkHidden("homedir")
 	runCmd.Flags().StringVarP(&iface, "iface", "", "", `Update DNS setting for iface, "auto" means the default interface gateway`)
@@ -298,6 +293,10 @@ func initCLI() {
 
 			processCDFlags()
 
+			if err := ctrld.ValidateConfig(validator.New(), &cfg); err != nil {
+				mainLog.Fatal().Msgf("invalid config: %v", err)
+			}
+
 			// Explicitly passing config, so on system where home directory could not be obtained,
 			// or sub-process env is different with the parent, we still behave correctly and use
 			// the expected config file.
@@ -319,7 +318,7 @@ func initCLI() {
 				{s.Start, true},
 			}
 			if doTasks(tasks) {
-				if err := router.PostInstall(); err != nil {
+				if err := router.PostInstall(svcConfig); err != nil {
 					mainLog.Warn().Err(err).Msg("post installation failed, please check system/service log for details error")
 					return
 				}
@@ -329,7 +328,8 @@ func initCLI() {
 					return
 				}
 
-				status = selfCheckStatus(status)
+				domain := cfg.Upstream["0"].VerifyDomain()
+				status = selfCheckStatus(status, domain)
 				switch status {
 				case service.StatusRunning:
 					mainLog.Notice().Msg("Service started")
@@ -354,6 +354,8 @@ func initCLI() {
 	startCmd.Flags().StringVarP(&logPath, "log", "", "", "Path to log file")
 	startCmd.Flags().IntVarP(&cacheSize, "cache_size", "", 0, "Enable cache with size items")
 	startCmd.Flags().StringVarP(&cdUID, "cd", "", "", "Control D resolver uid")
+	startCmd.Flags().BoolVarP(&cdDev, "dev", "", false, "Use Control D dev resolver/domain")
+	_ = startCmd.Flags().MarkHidden("dev")
 	startCmd.Flags().StringVarP(&iface, "iface", "", "", `Update DNS setting for iface, "auto" means the default interface gateway`)
 	startCmd.Flags().BoolVarP(&setupRouter, "router", "", false, `setup for running on router platforms`)
 	_ = startCmd.Flags().MarkHidden("router")
@@ -474,7 +476,7 @@ NOTE: Uninstalling will set DNS to values provided by DHCP.`,
 				}
 				prog.resetDNS()
 				mainLog.Debug().Msg("Router cleanup")
-				if err := router.Cleanup(); err != nil {
+				if err := router.Cleanup(svcConfig); err != nil {
 					mainLog.Warn().Err(err).Msg("could not cleanup router")
 				}
 				mainLog.Notice().Msg("Service uninstalled")
@@ -708,7 +710,7 @@ func processCDFlags() {
 	}
 	logger := mainLog.With().Str("mode", "cd").Logger()
 	logger.Info().Msgf("fetching Controld D configuration from API: %s", cdUID)
-	resolverConfig, err := controld.FetchResolverConfig(cdUID, rootCmd.Version)
+	resolverConfig, err := controld.FetchResolverConfig(cdUID, rootCmd.Version, cdDev)
 	if uer, ok := err.(*controld.UtilityErrorResponse); ok && uer.ErrorField.Code == controld.InvalidConfigCode {
 		s, err := service.New(&prog{}, svcConfig)
 		if err != nil {
@@ -854,17 +856,25 @@ func netInterface(ifaceName string) (*net.Interface, error) {
 func defaultIfaceName() string {
 	dri, err := interfaces.DefaultRouteInterface()
 	if err != nil {
+		// On WSL 1, the route table does not have any default route. But the fact that
+		// it only uses /etc/resolv.conf for setup DNS, so we can use "lo" here.
+		if oi := osinfo.New(); strings.Contains(oi.String(), "Microsoft") {
+			return "lo"
+		}
 		mainLog.Fatal().Err(err).Msg("failed to get default route interface")
 	}
 	return dri
 }
 
-func selfCheckStatus(status service.Status) service.Status {
+func selfCheckStatus(status service.Status, domain string) service.Status {
+	if domain == "" {
+		// Nothing to do, return the status as-is.
+		return status
+	}
 	c := new(dns.Client)
 	bo := backoff.NewBackoff("self-check", logf, 10*time.Second)
 	bo.LogLongerThan = 500 * time.Millisecond
 	ctx := context.Background()
-	err := errors.New("query failed")
 	maxAttempts := 20
 	mainLog.Debug().Msg("Performing self-check")
 	var (
@@ -888,16 +898,16 @@ func selfCheckStatus(status service.Status) service.Status {
 		}
 		mu.Unlock()
 		m := new(dns.Msg)
-		m.SetQuestion(selfCheckFQDN+".", dns.TypeA)
+		m.SetQuestion(domain+".", dns.TypeA)
 		m.RecursionDesired = true
-		r, _, _ := c.ExchangeContext(ctx, m, net.JoinHostPort(lc.IP, strconv.Itoa(lc.Port)))
+		r, _, err := c.ExchangeContext(ctx, m, net.JoinHostPort(lc.IP, strconv.Itoa(lc.Port)))
 		if r != nil && r.Rcode == dns.RcodeSuccess && len(r.Answer) > 0 {
-			mainLog.Debug().Msgf("self-check against %q succeeded", selfCheckFQDN)
+			mainLog.Debug().Msgf("self-check against %q succeeded", domain)
 			return status
 		}
-		bo.BackOff(ctx, err)
+		bo.BackOff(ctx, fmt.Errorf("ExchangeContext: %w", err))
 	}
-	mainLog.Debug().Msgf("self-check against %q failed", selfCheckFQDN)
+	mainLog.Debug().Msgf("self-check against %q failed", domain)
 	return service.StatusUnknown
 }
 
@@ -907,7 +917,7 @@ func unsupportedPlatformHelp(cmd *cobra.Command) {
 
 func userHomeDir() (string, error) {
 	switch router.Name() {
-	case router.DDWrt, router.Merlin:
+	case router.DDWrt, router.Merlin, router.Tomato:
 		exe, err := os.Executable()
 		if err != nil {
 			return "", err

cmd/ctrld/cli_router.go

@@ -1,3 +1,5 @@
+//go:build linux || freebsd
+
 package main
 
 import (
@@ -42,12 +44,11 @@ func initRouterCLI() {
 			if platform == "auto" {
 				platform = router.Name()
 			}
-			switch platform {
+			if !router.IsSupported(platform) {
-			case router.DDWrt, router.Merlin, router.OpenWrt, router.Ubios:
-			default:
 				unsupportedPlatformHelp(cmd)
 				os.Exit(1)
 			}
+
 			exe, err := os.Executable()
 			if err != nil {
 				mainLog.Fatal().Msgf("could not find executable path: %v", err)
@@ -76,6 +77,8 @@ func initRouterCLI() {
 	routerCmd.Flags().StringVarP(&logPath, "log", "", "", "Path to log file")
 	routerCmd.Flags().IntVarP(&cacheSize, "cache_size", "", 0, "Enable cache with size items")
 	routerCmd.Flags().StringVarP(&cdUID, "cd", "", "", "Control D resolver uid")
+	routerCmd.Flags().BoolVarP(&cdDev, "dev", "", false, "Use Control D dev resolver/domain")
+	_ = routerCmd.Flags().MarkHidden("dev")
 	routerCmd.Flags().StringVarP(&iface, "iface", "", "", `Update DNS setting for iface, "auto" means the default interface gateway`)
 
 	tmpl := routerCmd.UsageTemplate()

cmd/ctrld/cli_router_others.go

@@ -1,4 +1,4 @@
-//go:build !linux
+//go:build !linux && !freebsd
 
 package main
 

cmd/ctrld/dns_proxy.go

@@ -50,11 +50,12 @@ func (p *prog) serveDNS(listenerNum string) error {
 		q := m.Question[0]
 		domain := canonicalName(q.Name)
 		reqId := requestID()
-		fmtSrcToDest := fmtRemoteToLocal(listenerNum, w.RemoteAddr().String(), w.LocalAddr().String())
+		remoteAddr := spoofRemoteAddr(w.RemoteAddr(), router.GetClientInfoByMac(macFromMsg(m)))
+		fmtSrcToDest := fmtRemoteToLocal(listenerNum, remoteAddr.String(), w.LocalAddr().String())
 		t := time.Now()
 		ctx := context.WithValue(context.Background(), ctrld.ReqIdCtxKey{}, reqId)
 		ctrld.Log(ctx, mainLog.Debug(), "%s received query: %s %s", fmtSrcToDest, dns.TypeToString[q.Qtype], domain)
-		upstreams, matched := p.upstreamFor(ctx, listenerNum, listenerConfig, w.RemoteAddr(), domain)
+		upstreams, matched := p.upstreamFor(ctx, listenerNum, listenerConfig, remoteAddr, domain)
 		var answer *dns.Msg
 		if !matched && listenerConfig.Restricted {
 			answer = new(dns.Msg)
@@ -418,6 +419,28 @@ func macFromMsg(msg *dns.Msg) string {
 	return ""
 }
 
+func spoofRemoteAddr(addr net.Addr, ci *ctrld.ClientInfo) net.Addr {
+	if ci != nil && ci.IP != "" {
+		switch addr := addr.(type) {
+		case *net.UDPAddr:
+			udpAddr := &net.UDPAddr{
+				IP:   net.ParseIP(ci.IP),
+				Port: addr.Port,
+				Zone: addr.Zone,
+			}
+			return udpAddr
+		case *net.TCPAddr:
+			udpAddr := &net.TCPAddr{
+				IP:   net.ParseIP(ci.IP),
+				Port: addr.Port,
+				Zone: addr.Zone,
+			}
+			return udpAddr
+		}
+	}
+	return addr
+}
+
 // runDNSServer starts a DNS server for given address and network,
 // with the given handler. It ensures the server has started listening.
 // Any error will be reported to the caller via returned channel.
@@ -446,3 +469,51 @@ func runDNSServer(addr, network string, handler dns.Handler) (*dns.Server, <-cha
 	waitLock.Lock()
 	return s, errCh
 }
+
+// runDNSServerForNTPD starts a DNS server listening on router.ListenAddress(). It must only be called when ctrld
+// running on router, before router.PreRun() to serve DNS request for NTP synchronization. The caller must call
+// s.Shutdown() explicitly when NTP is synced successfully.
+func runDNSServerForNTPD(addr string) (*dns.Server, <-chan error) {
+	if addr == "" {
+		return &dns.Server{}, nil
+	}
+	dnsResolver := ctrld.NewBootstrapResolver()
+	s := &dns.Server{
+		Addr: addr,
+		Net:  "udp",
+		Handler: dns.HandlerFunc(func(w dns.ResponseWriter, m *dns.Msg) {
+			mainLog.Debug().Msg("Serving query for ntpd")
+			resolveCtx, cancel := context.WithCancel(context.Background())
+			defer cancel()
+			if osUpstreamConfig.Timeout > 0 {
+				timeoutCtx, cancel := context.WithTimeout(resolveCtx, time.Millisecond*time.Duration(osUpstreamConfig.Timeout))
+				defer cancel()
+				resolveCtx = timeoutCtx
+			}
+			answer, err := dnsResolver.Resolve(resolveCtx, m)
+			if err != nil {
+				mainLog.Error().Err(err).Msgf("could not resolve: %v", m)
+				return
+			}
+			if err := w.WriteMsg(answer); err != nil {
+				mainLog.Error().Err(err).Msg("runDNSServerForNTPD: failed to send DNS response")
+			}
+		}),
+	}
+
+	waitLock := sync.Mutex{}
+	waitLock.Lock()
+	s.NotifyStartedFunc = waitLock.Unlock
+
+	errCh := make(chan error)
+	go func() {
+		defer close(errCh)
+		if err := s.ListenAndServe(); err != nil {
+			waitLock.Unlock()
+			mainLog.Error().Err(err).Msgf("could not listen and serve on: %s", s.Addr)
+			errCh <- err
+		}
+	}()
+	waitLock.Lock()
+	return s, errCh
+}

cmd/ctrld/dns_proxy_test.go

@@ -174,7 +174,7 @@ func Test_macFromMsg(t *testing.T) {
 				t.Fatal(err)
 			}
 			m := new(dns.Msg)
-			m.SetQuestion(selfCheckFQDN+".", dns.TypeA)
+			m.SetQuestion("example.com.", dns.TypeA)
 			o := &dns.OPT{Hdr: dns.RR_Header{Name: ".", Rrtype: dns.TypeOPT}}
 			if tc.wantMac {
 				ec1 := &dns.EDNS0_LOCAL{Code: EDNS0_OPTION_MAC, Data: hw}
@@ -191,3 +191,28 @@ func Test_macFromMsg(t *testing.T) {
 		})
 	}
 }
+
+func Test_remoteAddrFromMsg(t *testing.T) {
+	loopbackIP := net.ParseIP("127.0.0.1")
+	tests := []struct {
+		name string
+		addr net.Addr
+		ci   *ctrld.ClientInfo
+		want string
+	}{
+		{"tcp", &net.TCPAddr{IP: loopbackIP, Port: 12345}, &ctrld.ClientInfo{IP: "192.168.1.10"}, "192.168.1.10:12345"},
+		{"udp", &net.UDPAddr{IP: loopbackIP, Port: 12345}, &ctrld.ClientInfo{IP: "192.168.1.11"}, "192.168.1.11:12345"},
+		{"nil client info", &net.UDPAddr{IP: loopbackIP, Port: 12345}, nil, "127.0.0.1:12345"},
+		{"empty ip", &net.UDPAddr{IP: loopbackIP, Port: 12345}, &ctrld.ClientInfo{}, "127.0.0.1:12345"},
+	}
+	for _, tc := range tests {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			addr := spoofRemoteAddr(tc.addr, tc.ci)
+			if addr.String() != tc.want {
+				t.Errorf("unexpected result, want: %q, got: %q", tc.want, addr.String())
+			}
+		})
+	}
+}

cmd/ctrld/main.go

@@ -27,6 +27,7 @@ var (
 	verbose           int
 	silent            bool
 	cdUID             string
+	cdDev             bool
 	iface             string
 	ifaceStartStop    string
 	setupRouter       bool

cmd/ctrld/prog.go

@@ -175,7 +175,10 @@ func (p *prog) setDNS() {
 	switch router.Name() {
 	case router.DDWrt, router.OpenWrt, router.Ubios:
 		// On router, ctrld run as a DNS forwarder, it does not have to change system DNS.
-		// Except for Merlin, which has WAN DNS setup on boot for NTP.
+		// Except for:
+		//   + EdgeOS, which /etc/resolv.conf could be managed by vyatta_update_resolv.pl script.
+		//   + Merlin/Tomato, which has WAN DNS setup on boot for NTP.
+		//   + Synology, which /etc/resolv.conf is not configured to point to localhost.
 		return
 	}
 	if cfg.Listener == nil || cfg.Listener["0"] == nil {

cmd/ctrld/prog_linux.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"github.com/kardianos/service"
+
+	"github.com/Control-D-Inc/ctrld/internal/router"
 )
 
 func (p *prog) preRun() {
@@ -17,6 +19,13 @@ func setDependencies(svc *service.Config) {
 		"Wants=NetworkManager-wait-online.service",
 		"After=NetworkManager-wait-online.service",
 	}
+	// On EdeOS, ctrld needs to start after vyatta-dhcpd, so it can read leases file.
+	if router.Name() == router.EdgeOS {
+		svc.Dependencies = append(svc.Dependencies, "Wants=vyatta-dhcpd.service")
+		svc.Dependencies = append(svc.Dependencies, "After=vyatta-dhcpd.service")
+		svc.Dependencies = append(svc.Dependencies, "Wants=dnsmasq.service")
+		svc.Dependencies = append(svc.Dependencies, "After=dnsmasq.service")
+	}
 }
 
 func setWorkingDirectory(svc *service.Config, dir string) {

cmd/ctrld/service.go

@@ -13,7 +13,8 @@ import (
 
 func newService(s service.Service) service.Service {
 	// TODO: unify for other SysV system.
-	if router.IsGLiNet() {
+	switch {
+	case router.IsGLiNet(), router.IsOldOpenwrt():
 		return &sysV{s}
 	}
 	return s

config.go

@@ -24,14 +24,31 @@ import (
 	ctrldnet "github.com/Control-D-Inc/ctrld/internal/net"
 )
 
+// IpStackBoth ...
 const (
-	IpStackBoth  = "both"
+	// IpStackBoth indicates that ctrld will use either ipv4 or ipv6 for connecting to upstream,
-	IpStackV4    = "v4"
+	// depending on which stack is available when receiving the DNS query.
-	IpStackV6    = "v6"
+	IpStackBoth = "both"
+	// IpStackV4 indicates that ctrld will use only ipv4 for connecting to upstream.
+	IpStackV4 = "v4"
+	// IpStackV6 indicates that ctrld will use only ipv6 for connecting to upstream.
+	IpStackV6 = "v6"
+	// IpStackSplit indicates that ctrld will use either ipv4 or ipv6 for connecting to upstream,
+	// depending on the record type of the DNS query.
 	IpStackSplit = "split"
+
+	controlDComDomain = "controld.com"
+	controlDNetDomain = "controld.net"
+	controlDDevDomain = "controld.dev"
 )
 
-var controldParentDomains = []string{"controld.com", "controld.net", "controld.dev"}
+var (
+	controldParentDomains  = []string{controlDComDomain, controlDNetDomain, controlDDevDomain}
+	controldVerifiedDomain = map[string]string{
+		controlDComDomain: "verify.controld.com",
+		controlDDevDomain: "verify.controld.dev",
+	}
+)
 
 // SetConfigName set the config name that ctrld will look for.
 // DEPRECATED: use SetConfigNameWithPath instead.
@@ -201,6 +218,23 @@ func (uc *UpstreamConfig) Init() {
 	}
 }
 
+// VerifyDomain returns the domain name that could be resolved by the upstream endpoint.
+// It returns empty for non-ControlD upstream endpoint.
+func (uc *UpstreamConfig) VerifyDomain() string {
+	domain := uc.Domain
+	if domain == "" {
+		if u, err := url.Parse(uc.Endpoint); err == nil {
+			domain = u.Hostname()
+		}
+	}
+	for _, parent := range controldParentDomains {
+		if dns.IsSubDomain(parent, domain) {
+			return controldVerifiedDomain[parent]
+		}
+	}
+	return ""
+}
+
 // UpstreamSendClientInfo reports whether the upstream is
 // configured to send client info to Control D DNS server.
 //
@@ -224,6 +258,7 @@ func (uc *UpstreamConfig) UpstreamSendClientInfo() bool {
 	return false
 }
 
+// BootstrapIPs returns the bootstrap IPs list of upstreams.
 func (uc *UpstreamConfig) BootstrapIPs() []string {
 	return uc.bootstrapIPs
 }
@@ -347,9 +382,7 @@ func (uc *UpstreamConfig) setupDOHTransportWithoutPingUpstream() {
 		uc.transport = uc.newDOHTransport(uc.bootstrapIPs6)
 	case IpStackSplit:
 		uc.transport4 = uc.newDOHTransport(uc.bootstrapIPs4)
-		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+		if hasIPv6() {
-		defer cancel()
-		if ctrldnet.IPv6Available(ctx) {
 			uc.transport6 = uc.newDOHTransport(uc.bootstrapIPs6)
 		} else {
 			uc.transport6 = uc.transport4
@@ -419,7 +452,10 @@ func (uc *UpstreamConfig) bootstrapIPForDNSType(dnsType uint16) string {
 		case dns.TypeA:
 			return pick(uc.bootstrapIPs4)
 		default:
-			return pick(uc.bootstrapIPs6)
+			if hasIPv6() {
+				return pick(uc.bootstrapIPs6)
+			}
+			return pick(uc.bootstrapIPs4)
 		}
 	}
 	return pick(uc.bootstrapIPs)
@@ -438,7 +474,10 @@ func (uc *UpstreamConfig) netForDNSType(dnsType uint16) (string, string) {
 		case dns.TypeA:
 			return "tcp4-tls", "udp4"
 		default:
-			return "tcp6-tls", "udp6"
+			if hasIPv6() {
+				return "tcp6-tls", "udp6"
+			}
+			return "tcp4-tls", "udp4"
 		}
 	}
 	return "tcp-tls", "udp"

config_internal_test.go

@@ -190,6 +190,39 @@ func TestUpstreamConfig_Init(t *testing.T) {
 	}
 }
 
+func TestUpstreamConfig_VerifyDomain(t *testing.T) {
+	tests := []struct {
+		name         string
+		uc           *UpstreamConfig
+		verifyDomain string
+	}{
+		{
+			controlDComDomain,
+			&UpstreamConfig{Endpoint: "https://freedns.controld.com/p2"},
+			controldVerifiedDomain[controlDComDomain],
+		},
+		{
+			controlDDevDomain,
+			&UpstreamConfig{Endpoint: "https://freedns.controld.dev/p2"},
+			controldVerifiedDomain[controlDDevDomain],
+		},
+		{
+			"non-ControlD upstream",
+			&UpstreamConfig{Endpoint: "https://dns.google/dns-query"},
+			"",
+		},
+	}
+
+	for _, tc := range tests {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			if got := tc.uc.VerifyDomain(); got != tc.verifyDomain {
+				t.Errorf("unexpected verify domain, want: %q, got: %q", tc.verifyDomain, got)
+			}
+		})
+	}
+}
 func ptrBool(b bool) *bool {
 	return &b
 }

config_quic.go

@@ -109,6 +109,7 @@ type parallelDialerResult struct {
 
 type quicParallelDialer struct{}
 
+// Dial performs parallel dialing to the given address list.
 func (d *quicParallelDialer) Dial(ctx context.Context, domain string, addrs []string, tlsCfg *tls.Config, cfg *quic.Config) (quic.EarlyConnection, error) {
 	if len(addrs) == 0 {
 		return nil, errors.New("empty addresses")

doh.go

@@ -13,10 +13,9 @@ import (
 )
 
 const (
-	DoHMacHeader  = "x-cd-mac"
+	dohMacHeader         = "x-cd-mac"
-	DoHIPHeader   = "x-cd-ip"
+	dohIPHeader          = "x-cd-ip"
-	DoHHostHeader = "x-cd-host"
+	dohHostHeader        = "x-cd-host"
-
 	headerApplicationDNS = "application/dns-message"
 )
 
@@ -101,13 +100,13 @@ func addHeader(ctx context.Context, req *http.Request, sendClientInfo bool) {
 	if sendClientInfo {
 		if ci, ok := ctx.Value(ClientInfoCtxKey{}).(*ClientInfo); ok && ci != nil {
 			if ci.Mac != "" {
-				req.Header.Set(DoHMacHeader, ci.Mac)
+				req.Header.Set(dohMacHeader, ci.Mac)
 			}
 			if ci.IP != "" {
-				req.Header.Set(DoHIPHeader, ci.IP)
+				req.Header.Set(dohIPHeader, ci.IP)
 			}
 			if ci.Hostname != "" {
-				req.Header.Set(DoHHostHeader, ci.Hostname)
+				req.Header.Set(dohHostHeader, ci.Hostname)
 			}
 		}
 	}

dot.go

@@ -33,6 +33,7 @@ func (r *dotResolver) Resolve(ctx context.Context, msg *dns.Msg) (*dns.Msg, erro
 	endpoint := r.uc.Endpoint
 	if r.uc.BootstrapIP != "" {
 		dnsClient.TLSConfig.ServerName = r.uc.Domain
+		dnsClient.Net = "tcp-tls"
 		_, port, _ := net.SplitHostPort(endpoint)
 		endpoint = net.JoinHostPort(r.uc.BootstrapIP, port)
 	}

internal/controld/config.go

@@ -17,9 +17,11 @@ import (
 )
 
 const (
-	apiDomain         = "api.controld.com"
+	apiDomainCom       = "api.controld.com"
-	resolverDataURL   = "https://api.controld.com/utility"
+	apiDomainDev       = "api.controld.dev"
-	InvalidConfigCode = 40401
+	resolverDataURLCom = "https://api.controld.com/utility"
+	resolverDataURLDev = "https://api.controld.dev/utility"
+	InvalidConfigCode  = 40401
 )
 
 // ResolverConfig represents Control D resolver data.
@@ -54,9 +56,13 @@ type utilityRequest struct {
 }
 
 // FetchResolverConfig fetch Control D config for given uid.
-func FetchResolverConfig(uid, version string) (*ResolverConfig, error) {
+func FetchResolverConfig(uid, version string, cdDev bool) (*ResolverConfig, error) {
 	body, _ := json.Marshal(utilityRequest{UID: uid})
-	req, err := http.NewRequest("POST", resolverDataURL, bytes.NewReader(body))
+	apiUrl := resolverDataURLCom
+	if cdDev {
+		apiUrl = resolverDataURLDev
+	}
+	req, err := http.NewRequest("POST", apiUrl, bytes.NewReader(body))
 	if err != nil {
 		return nil, fmt.Errorf("http.NewRequest: %w", err)
 	}
@@ -67,6 +73,10 @@ func FetchResolverConfig(uid, version string) (*ResolverConfig, error) {
 	req.Header.Add("Content-Type", "application/json")
 	transport := http.DefaultTransport.(*http.Transport).Clone()
 	transport.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
+		apiDomain := apiDomainCom
+		if cdDev {
+			apiDomain = apiDomainDev
+		}
 		ips := ctrld.LookupIP(apiDomain)
 		if len(ips) == 0 {
 			ctrld.ProxyLog.Warn().Msgf("No IPs found for %s, connecting to %s", apiDomain, addr)

internal/controld/config_test.go

@@ -13,16 +13,18 @@ func TestFetchResolverConfig(t *testing.T) {
 	tests := []struct {
 		name    string
 		uid     string
+		dev     bool
 		wantErr bool
 	}{
-		{"valid", "p2", false},
+		{"valid com", "p2", false, false},
-		{"invalid uid", "abcd1234", true},
+		{"valid dev", "p2", true, false},
+		{"invalid uid", "abcd1234", false, true},
 	}
 	for _, tc := range tests {
 		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
-			got, err := FetchResolverConfig(tc.uid, "dev-test")
+			got, err := FetchResolverConfig(tc.uid, "dev-test", tc.dev)
 			require.False(t, (err != nil) != tc.wantErr, err)
 			if !tc.wantErr {
 				assert.NotEmpty(t, got.DOH)

internal/router/client_info.go

@@ -1,6 +1,7 @@
 package router
 
 import (
+	"bufio"
 	"bytes"
 	"io"
 	"log"
@@ -15,14 +16,25 @@ import (
 	"github.com/Control-D-Inc/ctrld"
 )
 
-var clientInfoFiles = []string{
+// readClientInfoFunc represents the function for reading client info.
-	"/tmp/dnsmasq.leases",                  // ddwrt
+type readClientInfoFunc func(name string) error
-	"/tmp/dhcp.leases",                     // openwrt
+
-	"/var/lib/misc/dnsmasq.leases",         // merlin
+// clientInfoFiles specifies client info files and how to read them on supported platforms.
-	"/mnt/data/udapi-config/dnsmasq.lease", // UDM Pro
+var clientInfoFiles = map[string]readClientInfoFunc{
-	"/data/udapi-config/dnsmasq.lease",     // UDR
+	"/tmp/dnsmasq.leases":                  dnsmasqReadClientInfoFile, // ddwrt
+	"/tmp/dhcp.leases":                     dnsmasqReadClientInfoFile, // openwrt
+	"/var/lib/misc/dnsmasq.leases":         dnsmasqReadClientInfoFile, // merlin
+	"/mnt/data/udapi-config/dnsmasq.lease": dnsmasqReadClientInfoFile, // UDM Pro
+	"/data/udapi-config/dnsmasq.lease":     dnsmasqReadClientInfoFile, // UDR
+	"/etc/dhcpd/dhcpd-leases.log":          dnsmasqReadClientInfoFile, // Synology
+	"/tmp/var/lib/misc/dnsmasq.leases":     dnsmasqReadClientInfoFile, // Tomato
+	"/run/dnsmasq-dhcp.leases":             dnsmasqReadClientInfoFile, // EdgeOS
+	"/run/dhcpd.leases":                    iscDHCPReadClientInfoFile, // EdgeOS
+	"/var/dhcpd/var/db/dhcpd.leases":       iscDHCPReadClientInfoFile, // Pfsense
 }
 
+// watchClientInfoTable watches changes happens in dnsmasq/dhcpd
+// lease files, perform updating to mac table if necessary.
 func (r *router) watchClientInfoTable() {
 	if r.watcher == nil {
 		return
@@ -32,14 +44,19 @@ func (r *router) watchClientInfoTable() {
 		select {
 		case <-timer.C:
 			for _, name := range r.watcher.WatchList() {
-				_ = readClientInfoFile(name)
+				_ = clientInfoFiles[name](name)
 			}
 		case event, ok := <-r.watcher.Events:
 			if !ok {
 				return
 			}
 			if event.Has(fsnotify.Write) {
-				if err := readClientInfoFile(event.Name); err != nil && !os.IsNotExist(err) {
+				readFunc := clientInfoFiles[event.Name]
+				if readFunc == nil {
+					log.Println("unknown file format:", event.Name)
+					continue
+				}
+				if err := readFunc(event.Name); err != nil && !os.IsNotExist(err) {
 					log.Println("could not read client info file:", err)
 				}
 			}
@@ -52,6 +69,7 @@ func (r *router) watchClientInfoTable() {
 	}
 }
 
+// Stop performs tasks need to be done before the router stopped.
 func Stop() error {
 	if Name() == "" {
 		return nil
@@ -65,6 +83,7 @@ func Stop() error {
 	return nil
 }
 
+// GetClientInfoByMac returns ClientInfo for the client associated with the given mac.
 func GetClientInfoByMac(mac string) *ctrld.ClientInfo {
 	if mac == "" {
 		return nil
@@ -78,21 +97,23 @@ func GetClientInfoByMac(mac string) *ctrld.ClientInfo {
 	return val.(*ctrld.ClientInfo)
 }
 
-func readClientInfoFile(name string) error {
+// dnsmasqReadClientInfoFile populates mac table with client info reading from dnsmasq lease file.
+func dnsmasqReadClientInfoFile(name string) error {
 	f, err := os.Open(name)
 	if err != nil {
 		return err
 	}
 	defer f.Close()
-	return readClientInfoReader(f)
+	return dnsmasqReadClientInfoReader(f)
 
 }
 
-func readClientInfoReader(reader io.Reader) error {
+// dnsmasqReadClientInfoReader likes dnsmasqReadClientInfoFile, but reading from an io.Reader instead of file.
+func dnsmasqReadClientInfoReader(reader io.Reader) error {
 	r := routerPlatform.Load()
 	return lineread.Reader(reader, func(line []byte) error {
 		fields := bytes.Fields(line)
-		if len(fields) != 5 {
+		if len(fields) < 4 {
 			return nil
 		}
 		mac := string(fields[1])
@@ -111,6 +132,57 @@ func readClientInfoReader(reader io.Reader) error {
 	})
 }
 
+// iscDHCPReadClientInfoFile populates mac table with client info reading from isc-dhcpd lease file.
+func iscDHCPReadClientInfoFile(name string) error {
+	f, err := os.Open(name)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	return iscDHCPReadClientInfoReader(f)
+}
+
+// iscDHCPReadClientInfoReader likes iscDHCPReadClientInfoFile, but reading from an io.Reader instead of file.
+func iscDHCPReadClientInfoReader(reader io.Reader) error {
+	r := routerPlatform.Load()
+	s := bufio.NewScanner(reader)
+	var ip, mac, hostname string
+	for s.Scan() {
+		line := s.Text()
+		if strings.HasPrefix(line, "}") {
+			if mac != "" {
+				r.mac.Store(mac, &ctrld.ClientInfo{Mac: mac, IP: ip, Hostname: hostname})
+				ip, mac, hostname = "", "", ""
+			}
+			continue
+		}
+		fields := strings.Fields(line)
+		if len(fields) < 2 {
+			continue
+		}
+		switch fields[0] {
+		case "lease":
+			ip = normalizeIP(strings.ToLower(fields[1]))
+			if net.ParseIP(ip) == nil {
+				log.Printf("invalid ip address entry: %q", ip)
+				ip = ""
+			}
+		case "hardware":
+			if len(fields) >= 3 {
+				mac = strings.ToLower(strings.TrimRight(fields[2], ";"))
+				if _, err := net.ParseMAC(mac); err != nil {
+					// Invalid mac, skip.
+					mac = ""
+				}
+			}
+		case "client-hostname":
+			hostname = strings.Trim(fields[1], `";`)
+		}
+	}
+	return nil
+}
+
+// normalizeIP normalizes the ip parsed from dnsmasq/dhcpd lease file.
 func normalizeIP(in string) string {
 	// dnsmasq may put ip with interface index in lease file, strip it here.
 	ip, _, found := strings.Cut(in, "%")

internal/router/client_info_test.go

@@ -1,6 +1,7 @@
 package router
 
 import (
+	"io"
 	"strings"
 	"testing"
 
@@ -31,31 +32,65 @@ func Test_normalizeIP(t *testing.T) {
 
 func Test_readClientInfoReader(t *testing.T) {
 	tests := []struct {
-		name string
+		name     string
-		in   string
+		in       string
-		mac  string
+		readFunc func(r io.Reader) error
+		mac      string
 	}{
 		{
-			"good",
+			"good dnsmasq",
 			`1683329857 e6:20:59:b8:c1:6d 192.168.1.186 * 01:e6:20:59:b8:c1:6d
 `,
+			dnsmasqReadClientInfoReader,
 			"e6:20:59:b8:c1:6d",
 		},
 		{
-			"bad seen on UDMdream machine",
+			"bad dnsmasq seen on UDMdream machine",
 			`1683329857 e6:20:59:b8:c1:6e 192.168.1.111 * 01:e6:20:59:b8:c1:6e
 duid 00:01:00:01:2b:e4:2e:2c:52:52:14:26:dc:1c
 1683322985 117442354 2600:4040:b0e6:b700::111 ASDASD 00:01:00:01:2a:d0:b9:81:00:07:32:4c:1c:07
 `,
+			dnsmasqReadClientInfoReader,
 			"e6:20:59:b8:c1:6e",
 		},
+		{
+			"isc-dhcpd good",
+			`lease 192.168.1.1 {
+    hardware ethernet 00:00:00:00:00:01;
+    client-hostname "host-1";
+}
+`,
+			iscDHCPReadClientInfoReader,
+			"00:00:00:00:00:01",
+		},
+		{
+			"isc-dhcpd bad mac",
+			`lease 192.168.1.1 {
+    hardware ethernet invalid-mac;
+    client-hostname "host-1";
+}
+
+lease 192.168.1.2 {
+    hardware ethernet 00:00:00:00:00:02;
+    client-hostname "host-2";
+}
+`,
+			iscDHCPReadClientInfoReader,
+			"00:00:00:00:00:02",
+		},
+		{
+			"",
+			`1685794060 00:00:00:00:00:04 192.168.0.209 cuonglm-ThinkPad-X1-Carbon-Gen-9 00:00:00:00:00:04 9`,
+			dnsmasqReadClientInfoReader,
+			"00:00:00:00:00:04",
+		},
 	}
 
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
 			r := routerPlatform.Load()
 			r.mac.Delete(tc.mac)
-			if err := readClientInfoReader(strings.NewReader(tc.in)); err != nil {
+			if err := tc.readFunc(strings.NewReader(tc.in)); err != nil {
 				t.Errorf("readClientInfoReader() error = %v", err)
 			}
 			info, existed := r.mac.Load(tc.mac)
@@ -64,6 +99,8 @@ duid 00:01:00:01:2b:e4:2e:2c:52:52:14:26:dc:1c
 			}
 			if ci, ok := info.(*ctrld.ClientInfo); ok && existed && ci.Mac != tc.mac {
 				t.Errorf("mac mismatched, got: %q, want: %q", ci.Mac, tc.mac)
+			} else {
+				t.Log(ci)
 			}
 		})
 	}

internal/router/ddwrt.go

@@ -7,9 +7,10 @@ import (
 )
 
 const (
-	nvramCtrldKeyPrefix = "ctrld_"
+	nvramCtrldKeyPrefix  = "ctrld_"
-	nvramCtrldSetupKey  = "ctrld_setup"
+	nvramCtrldSetupKey   = "ctrld_setup"
-	nvramRCStartupKey   = "rc_startup"
+	nvramCtrldInstallKey = "ctrld_install"
+	nvramRCStartupKey    = "rc_startup"
 )
 
 //lint:ignore ST1005 This error is for human.
@@ -29,14 +30,14 @@ func setupDDWrt() error {
 		return err
 	}
 
-	nvramKvMap := nvramKV()
+	nvramKvMap := nvramSetupKV()
 	nvramKvMap["dnsmasq_options"] = data
-	if err := nvramSetup(nvramKvMap); err != nil {
+	if err := nvramSetKV(nvramKvMap, nvramCtrldSetupKey); err != nil {
 		return err
 	}
 
 	// Restart dnsmasq service.
-	if err := ddwrtRestartDNSMasq(); err != nil {
+	if err := restartDNSMasq(); err != nil {
 		return err
 	}
 	return nil
@@ -44,11 +45,11 @@ func setupDDWrt() error {
 
 func cleanupDDWrt() error {
 	// Restore old configs.
-	if err := nvramRestore(nvramKV()); err != nil {
+	if err := nvramRestore(nvramSetupKV(), nvramCtrldSetupKey); err != nil {
 		return err
 	}
 	// Restart dnsmasq service.
-	if err := ddwrtRestartDNSMasq(); err != nil {
+	if err := restartDNSMasq(); err != nil {
 		return err
 	}
 	return nil

internal/router/dnsmasq.go

@@ -49,7 +49,7 @@ func dnsMasqConf() (string, error) {
 	var sb strings.Builder
 	var tmplText string
 	switch Name() {
-	case DDWrt, OpenWrt, Ubios:
+	case EdgeOS, DDWrt, OpenWrt, Ubios, Synology, Tomato:
 		tmplText = dnsMasqConfigContentTmpl
 	case Merlin:
 		tmplText = merlinDNSMasqPostConfTmpl
@@ -65,3 +65,23 @@ func dnsMasqConf() (string, error) {
 	}
 	return sb.String(), nil
 }
+
+func restartDNSMasq() error {
+	switch Name() {
+	case EdgeOS:
+		return edgeOSRestartDNSMasq()
+	case DDWrt:
+		return ddwrtRestartDNSMasq()
+	case Merlin:
+		return merlinRestartDNSMasq()
+	case OpenWrt:
+		return openwrtRestartDNSMasq()
+	case Ubios:
+		return ubiosRestartDNSMasq()
+	case Synology:
+		return synologyRestartDNSMasq()
+	case Tomato:
+		return tomatoRestartService(tomatoDNSMasqSvcName)
+	}
+	panic("not supported platform")
+}

internal/router/edgeos.go

@@ -0,0 +1,56 @@
+package router
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+)
+
+const edgeOSDNSMasqConfigPath = "/etc/dnsmasq.d/dnsmasq-zzz-ctrld.conf"
+
+func setupEdgeOS() error {
+	// Disable dnsmasq as DNS server.
+	dnsMasqConfigContent, err := dnsMasqConf()
+	if err != nil {
+		return err
+	}
+	if err := os.WriteFile(edgeOSDNSMasqConfigPath, []byte(dnsMasqConfigContent), 0600); err != nil {
+		return err
+	}
+	// Restart dnsmasq service.
+	if err := restartDNSMasq(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func cleanupEdgeOS() error {
+	// Remove the custom dnsmasq config
+	if err := os.Remove(edgeOSDNSMasqConfigPath); err != nil {
+		return err
+	}
+	// Restart dnsmasq service.
+	if err := restartDNSMasq(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func postInstallEdgeOS() error {
+	// If "Content Filtering" is enabled, UniFi OS will create firewall rules to intercept all DNS queries
+	// from outside, and route those queries to separated interfaces (e.g: dnsfilter-2@if79) created by UniFi OS.
+	// Thus, those queries will never reach ctrld listener. UniFi OS does not provide any mechanism to toggle this
+	// feature via command line, so there's nothing ctrld can do to disable this feature. For now, reporting an
+	// error and guiding users to disable the feature using UniFi OS web UI.
+	if contentFilteringEnabled() {
+		return errContentFilteringEnabled
+	}
+	return nil
+}
+
+func edgeOSRestartDNSMasq() error {
+	if out, err := exec.Command("/etc/init.d/dnsmasq", "restart").CombinedOutput(); err != nil {
+		return fmt.Errorf("edgeosRestartDNSMasq: %s, %w", string(out), err)
+	}
+	return nil
+}

internal/router/merlin.go

@@ -35,11 +35,11 @@ func setupMerlin() error {
 		return err
 	}
 	// Restart dnsmasq service.
-	if err := merlinRestartDNSMasq(); err != nil {
+	if err := restartDNSMasq(); err != nil {
 		return err
 	}
 
-	if err := nvramSetup(nvramKV()); err != nil {
+	if err := nvramSetKV(nvramSetupKV(), nvramCtrldSetupKey); err != nil {
 		return err
 	}
 
@@ -48,7 +48,7 @@ func setupMerlin() error {
 
 func cleanupMerlin() error {
 	// Restore old configs.
-	if err := nvramRestore(nvramKV()); err != nil {
+	if err := nvramRestore(nvramSetupKV(), nvramCtrldSetupKey); err != nil {
 		return err
 	}
 	buf, err := os.ReadFile(merlinDNSMasqPostConfPath)
@@ -60,7 +60,7 @@ func cleanupMerlin() error {
 		return err
 	}
 	// Restart dnsmasq service.
-	if err := merlinRestartDNSMasq(); err != nil {
+	if err := restartDNSMasq(); err != nil {
 		return err
 	}
 	return nil

internal/router/nvram.go

@@ -26,7 +26,7 @@ NOTE:
     +https://community.ui.com/questions/Implement-DNSSEC-into-UniFi/951c72b0-4d88-4c86-9174-45417bd2f9ca
     +https://community.ui.com/questions/Enable-DNSSEC-for-Unifi-Dream-Machine-FW-updates/e68e367c-d09b-4459-9444-18908f7c1ea1
 */
-func nvramKV() map[string]string {
+func nvramSetupKV() map[string]string {
 	switch Name() {
 	case DDWrt:
 		return map[string]string{
@@ -39,11 +39,28 @@ func nvramKV() map[string]string {
 		return map[string]string{
 			"dnspriv_enable": "0", // Ensure Merlin native DoT disabled.
 		}
+	case Tomato:
+		return map[string]string{
+			"dnsmasq_custom": "",  // Configuration of dnsmasq set by ctrld, filled by setupTomato.
+			"dnscrypt_proxy": "0", // Disable DNSCrypt.
+			"dnssec_enable":  "0", // Disable DNSSEC.
+			"stubby_proxy":   "0", // Disable Stubby
+		}
 	}
 	return nil
 }
 
-func nvramSetup(m map[string]string) error {
+func nvramInstallKV() map[string]string {
+	switch Name() {
+	case Tomato:
+		return map[string]string{
+			tomatoNvramScriptWanupKey: "", // script to start ctrld, filled by tomatoSvc.Install method.
+		}
+	}
+	return nil
+}
+
+func nvramSetKV(m map[string]string, setupKey string) error {
 	// Backup current value, store ctrld's configs.
 	for key, value := range m {
 		old, err := nvram("get", key)
@@ -58,7 +75,7 @@ func nvramSetup(m map[string]string) error {
 		}
 	}
 
-	if out, err := nvram("set", nvramCtrldSetupKey+"=1"); err != nil {
+	if out, err := nvram("set", setupKey+"=1"); err != nil {
 		return fmt.Errorf("%s: %w", out, err)
 	}
 	// Commit.
@@ -68,7 +85,7 @@ func nvramSetup(m map[string]string) error {
 	return nil
 }
 
-func nvramRestore(m map[string]string) error {
+func nvramRestore(m map[string]string, setupKey string) error {
 	// Restore old configs.
 	for key := range m {
 		ctrldKey := nvramCtrldKeyPrefix + key
@@ -82,7 +99,7 @@ func nvramRestore(m map[string]string) error {
 		}
 	}
 
-	if out, err := nvram("unset", "ctrld_setup"); err != nil {
+	if out, err := nvram("unset", setupKey); err != nil {
 		return fmt.Errorf("%s: %w", out, err)
 	}
 	// Commit.

internal/router/openwrt.go

@@ -23,12 +23,21 @@ func IsGLiNet() bool {
 	return bytes.Contains(buf, []byte(" (glinet"))
 }
 
+// IsOldOpenwrt reports whether the router is an "old" version of Openwrt,
+// aka versions which don't have "service" command.
+func IsOldOpenwrt() bool {
+	if Name() != OpenWrt {
+		return false
+	}
+	cmd, _ := exec.LookPath("service")
+	return cmd == ""
+}
+
 func setupOpenWrt() error {
 	// Delete dnsmasq port if set.
 	if _, err := uci("delete", "dhcp.@dnsmasq[0].port"); err != nil && !errors.Is(err, errUCIEntryNotFound) {
 		return err
 	}
-	// Disable dnsmasq as DNS server.
 	dnsMasqConfigContent, err := dnsMasqConf()
 	if err != nil {
 		return err
@@ -41,7 +50,7 @@ func setupOpenWrt() error {
 		return err
 	}
 	// Restart dnsmasq service.
-	if err := openwrtRestartDNSMasq(); err != nil {
+	if err := restartDNSMasq(); err != nil {
 		return err
 	}
 	return nil
@@ -53,7 +62,7 @@ func cleanupOpenWrt() error {
 		return err
 	}
 	// Restart dnsmasq service.
-	if err := openwrtRestartDNSMasq(); err != nil {
+	if err := restartDNSMasq(); err != nil {
 		return err
 	}
 	return nil

internal/router/pfsense.go

@@ -0,0 +1,66 @@
+package router
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+
+	"github.com/kardianos/service"
+)
+
+const (
+	rcPath        = "/usr/local/etc/rc.d"
+	unboundRcPath = rcPath + "/unbound"
+	dnsmasqRcPath = rcPath + "/dnsmasq"
+)
+
+func setupPfsense() error {
+	// If Pfsense is in DNS Resolver mode, ensure no unbound processes running.
+	_ = exec.Command("killall", "unbound").Run()
+
+	// If Pfsense is in DNS Forwarder mode, ensure no dnsmasq processes running.
+	_ = exec.Command("killall", "dnsmasq").Run()
+	return nil
+}
+
+func cleanupPfsense(svc *service.Config) error {
+	if err := os.Remove(filepath.Join(rcPath, svc.Name+".sh")); err != nil {
+		return fmt.Errorf("os.Remove: %w", err)
+	}
+	_ = exec.Command(unboundRcPath, "onerestart").Run()
+	_ = exec.Command(dnsmasqRcPath, "onerestart").Run()
+
+	return nil
+}
+
+func postInstallPfsense(svc *service.Config) error {
+	// pfsense need ".sh" extension for script to be run at boot.
+	// See: https://docs.netgate.com/pfsense/en/latest/development/boot-commands.html#shell-script-option
+	oldname := filepath.Join(rcPath, svc.Name)
+	newname := filepath.Join(rcPath, svc.Name+".sh")
+	_ = os.Remove(newname)
+	if err := os.Symlink(oldname, newname); err != nil {
+		return fmt.Errorf("os.Symlink: %w", err)
+	}
+	return nil
+}
+
+const pfsenseInitScript = `#!/bin/sh
+
+# PROVIDE: {{.Name}}
+# REQUIRE: SERVERS
+# REQUIRE: unbound dnsmasq securelevel
+# KEYWORD: shutdown
+
+. /etc/rc.subr
+
+name="{{.Name}}"
+{{.Name}}_env="IS_DAEMON=1"
+pidfile="/var/run/${name}.pid"
+command="/usr/sbin/daemon"
+daemon_args="-P ${pidfile} -r -t \"${name}: daemon\"{{if .WorkingDirectory}} -c {{.WorkingDirectory}}{{end}}"
+command_args="${daemon_args} {{.Path}}{{range .Arguments}} {{.}}{{end}}"
+
+run_rc_command "$1"
+`

internal/router/router.go

@@ -19,10 +19,14 @@ import (
 )
 
 const (
-	OpenWrt = "openwrt"
+	OpenWrt  = "openwrt"
-	DDWrt   = "ddwrt"
+	DDWrt    = "ddwrt"
-	Merlin  = "merlin"
+	Merlin   = "merlin"
-	Ubios   = "ubios"
+	Ubios    = "ubios"
+	Synology = "synology"
+	Tomato   = "tomato"
+	EdgeOS   = "edgeos"
+	Pfsense  = "pfsense"
 )
 
 // ErrNotSupported reports the current router is not supported error.
@@ -37,23 +41,36 @@ type router struct {
 	watcher        *fsnotify.Watcher
 }
 
+// IsSupported reports whether the given platform is supported by ctrld.
+func IsSupported(platform string) bool {
+	switch platform {
+	case EdgeOS, DDWrt, Merlin, OpenWrt, Pfsense, Synology, Tomato, Ubios:
+		return true
+	}
+	return false
+}
+
 // SupportedPlatforms return all platforms that can be configured to run with ctrld.
 func SupportedPlatforms() []string {
-	return []string{DDWrt, Merlin, OpenWrt, Ubios}
+	return []string{EdgeOS, DDWrt, Merlin, OpenWrt, Pfsense, Synology, Tomato, Ubios}
 }
 
 var configureFunc = map[string]func() error{
-	DDWrt:   setupDDWrt,
+	EdgeOS:   setupEdgeOS,
-	Merlin:  setupMerlin,
+	DDWrt:    setupDDWrt,
-	OpenWrt: setupOpenWrt,
+	Merlin:   setupMerlin,
-	Ubios:   setupUbiOS,
+	OpenWrt:  setupOpenWrt,
+	Pfsense:  setupPfsense,
+	Synology: setupSynology,
+	Tomato:   setupTomato,
+	Ubios:    setupUbiOS,
 }
 
 // Configure configures things for running ctrld on the router.
 func Configure(c *ctrld.Config) error {
 	name := Name()
 	switch name {
-	case DDWrt, Merlin, OpenWrt, Ubios:
+	case EdgeOS, DDWrt, Merlin, OpenWrt, Pfsense, Synology, Tomato, Ubios:
 		if c.HasUpstreamSendClientInfo() {
 			r := routerPlatform.Load()
 			r.sendClientInfo = true
@@ -63,8 +80,8 @@ func Configure(c *ctrld.Config) error {
 			}
 			r.watcher = watcher
 			go r.watchClientInfoTable()
-			for _, file := range clientInfoFiles {
+			for file, readClienInfoFunc := range clientInfoFiles {
-				_ = readClientInfoFile(file)
+				_ = readClienInfoFunc(file)
 				_ = r.watcher.Add(file)
 			}
 		}
@@ -88,67 +105,53 @@ func ConfigureService(sc *service.Config) error {
 		}
 	case OpenWrt:
 		sc.Option["SysvScript"] = openWrtScript
-	case Merlin, Ubios:
+	case Pfsense:
+		sc.Option["SysvScript"] = pfsenseInitScript
+	case EdgeOS, Merlin, Synology, Tomato, Ubios:
 	}
 	return nil
 }
 
-// PreStart blocks until the router is ready for running ctrld.
+// PreRun blocks until the router is ready for running ctrld.
-func PreStart() (err error) {
+func PreRun() (err error) {
-	if Name() != DDWrt {
+	// On some routers, NTP may out of sync, so waiting for it to be ready.
+	switch Name() {
+	case Merlin, Tomato:
+		// Wait until `ntp_ready=1` set.
+		b := backoff.NewBackoff("PreStart", func(format string, args ...any) {}, 10*time.Second)
+		for {
+			out, err := nvram("get", "ntp_ready")
+			if err != nil {
+				return fmt.Errorf("PreStart: nvram: %w", err)
+			}
+			if out == "1" {
+				return nil
+			}
+			b.BackOff(context.Background(), errors.New("ntp not ready"))
+		}
+	default:
 		return nil
 	}
-
-	pidFile := "/tmp/ctrld.pid"
-	// On Merlin, NTP may out of sync, so waiting for it to be ready.
-	//
-	// Remove pid file and trigger dnsmasq restart, so NTP can resolve
-	// server name and perform time synchronization.
-	pid, err := os.ReadFile(pidFile)
-	if err != nil {
-		return fmt.Errorf("PreStart: os.Readfile: %w", err)
-	}
-	if err := os.Remove(pidFile); err != nil {
-		return fmt.Errorf("PreStart: os.Remove: %w", err)
-	}
-	defer func() {
-		if werr := os.WriteFile(pidFile, pid, 0600); werr != nil {
-			err = errors.Join(err, werr)
-			return
-		}
-		if rerr := merlinRestartDNSMasq(); rerr != nil {
-			err = errors.Join(err, rerr)
-			return
-		}
-	}()
-	if err := merlinRestartDNSMasq(); err != nil {
-		return fmt.Errorf("PreStart: merlinRestartDNSMasq: %w", err)
-	}
-
-	// Wait until `ntp_read=1` set.
-	b := backoff.NewBackoff("PreStart", func(format string, args ...any) {}, 10*time.Second)
-	for {
-		out, err := nvram("get", "ntp_ready")
-		if err != nil {
-			return fmt.Errorf("PreStart: nvram: %w", err)
-		}
-		if out == "1" {
-			return nil
-		}
-		b.BackOff(context.Background(), errors.New("ntp not ready"))
-	}
 }
 
 // PostInstall performs task after installing ctrld on router.
-func PostInstall() error {
+func PostInstall(svc *service.Config) error {
 	name := Name()
 	switch name {
+	case EdgeOS:
+		return postInstallEdgeOS()
 	case DDWrt:
 		return postInstallDDWrt()
 	case Merlin:
 		return postInstallMerlin()
 	case OpenWrt:
 		return postInstallOpenWrt()
+	case Pfsense:
+		return postInstallPfsense(svc)
+	case Synology:
+		return postInstallSynology()
+	case Tomato:
+		return postInstallTomato()
 	case Ubios:
 		return postInstallUbiOS()
 	}
@@ -156,15 +159,23 @@ func PostInstall() error {
 }
 
 // Cleanup cleans ctrld setup on the router.
-func Cleanup() error {
+func Cleanup(svc *service.Config) error {
 	name := Name()
 	switch name {
+	case EdgeOS:
+		return cleanupEdgeOS()
 	case DDWrt:
 		return cleanupDDWrt()
 	case Merlin:
 		return cleanupMerlin()
 	case OpenWrt:
 		return cleanupOpenWrt()
+	case Pfsense:
+		return cleanupPfsense(svc)
+	case Synology:
+		return cleanupSynology()
+	case Tomato:
+		return cleanupTomato()
 	case Ubios:
 		return cleanupUbiOS()
 	}
@@ -175,8 +186,10 @@ func Cleanup() error {
 func ListenAddress() string {
 	name := Name()
 	switch name {
-	case DDWrt, Merlin, OpenWrt, Ubios:
+	case EdgeOS, DDWrt, Merlin, OpenWrt, Synology, Tomato, Ubios:
 		return "127.0.0.1:5354"
+	case Pfsense:
+		// On pfsense, we run ctrld as DNS resolver.
 	}
 	return ""
 }
@@ -194,14 +207,24 @@ func Name() string {
 
 func distroName() string {
 	switch {
-	case bytes.HasPrefix(uname(), []byte("DD-WRT")):
+	case bytes.HasPrefix(unameO(), []byte("DD-WRT")):
 		return DDWrt
-	case bytes.HasPrefix(uname(), []byte("ASUSWRT-Merlin")):
+	case bytes.HasPrefix(unameO(), []byte("ASUSWRT-Merlin")):
 		return Merlin
 	case haveFile("/etc/openwrt_version"):
 		return OpenWrt
 	case haveDir("/data/unifi"):
 		return Ubios
+	case bytes.HasPrefix(unameU(), []byte("synology")):
+		return Synology
+	case bytes.HasPrefix(unameO(), []byte("Tomato")):
+		return Tomato
+	case haveDir("/config/scripts/post-config.d"):
+		return EdgeOS
+	case haveFile("/etc/ubnt/init/vyatta-router"):
+		return EdgeOS // For 2.x
+	case isPfsense():
+		return Pfsense
 	}
 	return ""
 }
@@ -216,7 +239,17 @@ func haveDir(dir string) bool {
 	return fi != nil && fi.IsDir()
 }
 
-func uname() []byte {
+func unameO() []byte {
 	out, _ := exec.Command("uname", "-o").Output()
 	return out
 }
+
+func unameU() []byte {
+	out, _ := exec.Command("uname", "-u").Output()
+	return out
+}
+
+func isPfsense() bool {
+	b, err := os.ReadFile("/etc/platform")
+	return err == nil && bytes.HasPrefix(b, []byte("pfSense"))
+}

internal/router/service.go

@@ -48,6 +48,15 @@ func init() {
 			},
 			new: newUbiosService,
 		},
+		&linuxSystemService{
+			name:   "tomato",
+			detect: func() bool { return Name() == Tomato },
+			interactive: func() bool {
+				is, _ := isInteractive()
+				return is
+			},
+			new: newTomatoService,
+		},
 	}
 	systems = append(systems, service.AvailableSystems()...)
 	service.ChooseSystem(systems...)

internal/router/service_tomato.go

@@ -0,0 +1,278 @@
+package router
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"os/signal"
+	"strings"
+	"syscall"
+	"text/template"
+
+	"github.com/kardianos/service"
+)
+
+const tomatoNvramScriptWanupKey = "script_wanup"
+
+type tomatoSvc struct {
+	i        service.Interface
+	platform string
+	*service.Config
+}
+
+func newTomatoService(i service.Interface, platform string, c *service.Config) (service.Service, error) {
+	s := &tomatoSvc{
+		i:        i,
+		platform: platform,
+		Config:   c,
+	}
+	return s, nil
+}
+
+func (s *tomatoSvc) String() string {
+	if len(s.DisplayName) > 0 {
+		return s.DisplayName
+	}
+	return s.Name
+}
+
+func (s *tomatoSvc) Platform() string {
+	return s.platform
+}
+
+func (s *tomatoSvc) configPath() string {
+	path, err := os.Executable()
+	if err != nil {
+		return ""
+	}
+	return path + ".startup"
+}
+
+func (s *tomatoSvc) template() *template.Template {
+	return template.Must(template.New("").Parse(tomatoSvcScript))
+}
+
+func (s *tomatoSvc) Install() error {
+	exePath, err := os.Executable()
+	if err != nil {
+		return err
+	}
+
+	if !strings.HasPrefix(exePath, "/jffs/") {
+		return errors.New("could not install service outside /jffs")
+	}
+	if _, err := nvram("set", "jffs2_on=1"); err != nil {
+		return err
+	}
+	if _, err := nvram("commit"); err != nil {
+		return err
+	}
+
+	confPath := s.configPath()
+	if _, err := os.Stat(confPath); err == nil {
+		return fmt.Errorf("already installed: %s", confPath)
+	}
+
+	var to = &struct {
+		*service.Config
+		Path string
+	}{
+		s.Config,
+		exePath,
+	}
+
+	f, err := os.Create(confPath)
+	if err != nil {
+		return fmt.Errorf("os.Create: %w", err)
+	}
+	defer f.Close()
+
+	if err := s.template().Execute(f, to); err != nil {
+		return fmt.Errorf("s.template.Execute: %w", err)
+	}
+
+	if err = os.Chmod(confPath, 0755); err != nil {
+		return fmt.Errorf("os.Chmod: startup script: %w", err)
+	}
+
+	nvramKvMap := nvramInstallKV()
+	old, err := nvram("get", tomatoNvramScriptWanupKey)
+	if err != nil {
+		return fmt.Errorf("nvram: %w", err)
+	}
+	nvramKvMap[tomatoNvramScriptWanupKey] = strings.Join([]string{old, s.configPath() + " start"}, "\n")
+	if err := nvramSetKV(nvramKvMap, nvramCtrldInstallKey); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (s *tomatoSvc) Uninstall() error {
+	if err := os.Remove(s.configPath()); err != nil {
+		return fmt.Errorf("os.Remove: %w", err)
+	}
+	// Restore old configs.
+	if err := nvramRestore(nvramInstallKV(), nvramCtrldInstallKey); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (s *tomatoSvc) Logger(errs chan<- error) (service.Logger, error) {
+	if service.Interactive() {
+		return service.ConsoleLogger, nil
+	}
+	return s.SystemLogger(errs)
+}
+
+func (s *tomatoSvc) SystemLogger(errs chan<- error) (service.Logger, error) {
+	return newSysLogger(s.Name, errs)
+}
+
+func (s *tomatoSvc) Run() (err error) {
+	err = s.i.Start(s)
+	if err != nil {
+		return err
+	}
+
+	if interactice, _ := isInteractive(); !interactice {
+		signal.Ignore(syscall.SIGHUP)
+	}
+
+	var sigChan = make(chan os.Signal, 1)
+	signal.Notify(sigChan, syscall.SIGTERM, os.Interrupt)
+	<-sigChan
+
+	return s.i.Stop(s)
+}
+
+func (s *tomatoSvc) Status() (service.Status, error) {
+	if _, err := os.Stat(s.configPath()); os.IsNotExist(err) {
+		return service.StatusUnknown, service.ErrNotInstalled
+	}
+	out, err := exec.Command(s.configPath(), "status").CombinedOutput()
+	if err != nil {
+		return service.StatusUnknown, err
+	}
+	switch string(bytes.TrimSpace(out)) {
+	case "running":
+		return service.StatusRunning, nil
+	default:
+		return service.StatusStopped, nil
+	}
+}
+
+func (s *tomatoSvc) Start() error {
+	return exec.Command(s.configPath(), "start").Run()
+}
+
+func (s *tomatoSvc) Stop() error {
+	return exec.Command(s.configPath(), "stop").Run()
+}
+
+func (s *tomatoSvc) Restart() error {
+	return exec.Command(s.configPath(), "restart").Run()
+}
+
+// https://wiki.freshtomato.org/doku.php/freshtomato_zerotier?s[]=%2Aservice%2A
+const tomatoSvcScript = `#!/bin/sh
+ 
+
+NAME="{{.Name}}"
+CMD="{{.Path}}{{range .Arguments}} {{.}}{{end}}"
+LOG_FILE="/var/log/${NAME}.log"
+PID_FILE="/tmp/$NAME.pid"
+ 
+ 
+alias elog="logger -t $NAME -s"
+ 
+ 
+COND=$1
+[ $# -eq 0 ] && COND="start"
+ 
+get_pid() {
+  cat "$PID_FILE"
+}
+
+is_running() {
+  [ -f "$PID_FILE" ] && ps | grep -q "^ *$(get_pid) "
+}
+
+start() {
+  if is_running; then
+    elog "$NAME is already running."
+    exit 1
+  fi
+  elog "Starting $NAME Services: "
+  $CMD &
+  echo $! > "$PID_FILE"
+  chmod 600 "$PID_FILE"
+  if is_running; then
+    elog "succeeded."
+  else
+    elog "failed."
+  fi
+}
+ 
+ 
+stop() {
+  if ! is_running; then
+    elog "$NAME is not running."
+    exit 1
+  fi
+  elog "Shutting down $NAME Services: "
+  kill -SIGTERM "$(get_pid)"
+  for _ in 1 2 3 4 5; do
+    if ! is_running; then
+      if [ -f "$pid_file" ]; then
+        rm "$pid_file"
+      fi
+      return 0
+    fi
+    printf "."
+    sleep 2
+  done
+  if ! is_running; then
+    elog "succeeded."
+  else
+    elog "failed."
+  fi
+}
+ 
+ 
+do_restart() {
+  stop
+  start
+}
+
+
+do_status() {
+  if ! is_running; then
+    echo "stopped"
+  else
+    echo "running"
+  fi
+}
+ 
+ 
+case "$COND" in
+start)
+  start
+  ;;
+stop)
+  stop
+  ;;
+restart)
+  do_restart
+  ;;
+status)
+  do_status
+  ;;
+*)
+  elog "Usage: $0 (start|stop|restart|status)"
+  ;;
+esac
+exit 0
+`

internal/router/synology.go

@@ -0,0 +1,55 @@
+package router
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+)
+
+const (
+	synologyDNSMasqConfigPath = "/etc/dhcpd/dhcpd-zzz-ctrld.conf"
+	synologyDhcpdInfoPath     = "/etc/dhcpd/dhcpd-zzz-ctrld.info"
+)
+
+func setupSynology() error {
+	dnsMasqConfigContent, err := dnsMasqConf()
+	if err != nil {
+		return err
+	}
+	if err := os.WriteFile(synologyDNSMasqConfigPath, []byte(dnsMasqConfigContent), 0600); err != nil {
+		return err
+	}
+	if err := os.WriteFile(synologyDhcpdInfoPath, []byte(`enable="yes"`), 0600); err != nil {
+		return err
+	}
+	if err := restartDNSMasq(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func cleanupSynology() error {
+	// Remove the custom config files.
+	for _, f := range []string{synologyDNSMasqConfigPath, synologyDhcpdInfoPath} {
+		if err := os.Remove(f); err != nil {
+			return err
+		}
+	}
+
+	// Restart dnsmasq service.
+	if err := restartDNSMasq(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func postInstallSynology() error {
+	return nil
+}
+
+func synologyRestartDNSMasq() error {
+	if out, err := exec.Command("/etc/rc.network", "nat-restart-dhcp").CombinedOutput(); err != nil {
+		return fmt.Errorf("synologyRestartDNSMasq: %s - %w", string(out), err)
+	}
+	return nil
+}

internal/router/tomato.go

@@ -0,0 +1,82 @@
+package router
+
+import (
+	"fmt"
+	"os/exec"
+)
+
+const (
+	tomatoDnsCryptProxySvcName = "dnscrypt-proxy"
+	tomatoStubbySvcName        = "stubby"
+	tomatoDNSMasqSvcName       = "dnsmasq"
+)
+
+func setupTomato() error {
+	// Already setup.
+	if val, _ := nvram("get", nvramCtrldSetupKey); val == "1" {
+		return nil
+	}
+
+	data, err := dnsMasqConf()
+	if err != nil {
+		return err
+	}
+
+	nvramKvMap := nvramSetupKV()
+	nvramKvMap["dnsmasq_custom"] = data
+	if err := nvramSetKV(nvramKvMap, nvramCtrldSetupKey); err != nil {
+		return err
+	}
+
+	// Restart dnscrypt-proxy service.
+	if err := tomatoRestartServiceWithKill(tomatoDnsCryptProxySvcName, true); err != nil {
+		return err
+	}
+	// Restart stubby service.
+	if err := tomatoRestartService(tomatoStubbySvcName); err != nil {
+		return err
+	}
+	// Restart dnsmasq service.
+	if err := restartDNSMasq(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func postInstallTomato() error {
+	return nil
+}
+
+func cleanupTomato() error {
+	// Restore old configs.
+	if err := nvramRestore(nvramSetupKV(), nvramCtrldSetupKey); err != nil {
+		return err
+	}
+	// Restart dnscrypt-proxy service.
+	if err := tomatoRestartServiceWithKill(tomatoDnsCryptProxySvcName, true); err != nil {
+		return err
+	}
+	// Restart stubby service.
+	if err := tomatoRestartService(tomatoStubbySvcName); err != nil {
+		return err
+	}
+	// Restart dnsmasq service.
+	if err := restartDNSMasq(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func tomatoRestartService(name string) error {
+	return tomatoRestartServiceWithKill(name, false)
+}
+
+func tomatoRestartServiceWithKill(name string, killBeforeRestart bool) error {
+	if killBeforeRestart {
+		_, _ = exec.Command("killall", name).CombinedOutput()
+	}
+	if out, err := exec.Command("service", name, "restart").CombinedOutput(); err != nil {
+		return fmt.Errorf("service restart %s: %s, %w", name, string(out), err)
+	}
+	return nil
+}

internal/router/ubios.go

@@ -2,12 +2,17 @@ package router
 
 import (
 	"bytes"
+	"fmt"
 	"os"
 	"strconv"
 )
 
+var errContentFilteringEnabled = fmt.Errorf(`the "Content Filtering" feature" is enabled, which is conflicted with ctrld.\n
+To disable it, folowing instruction here: %s`, toggleContentFilteringLink)
+
 const (
-	ubiosDNSMasqConfigPath = "/run/dnsmasq.conf.d/zzzctrld.conf"
+	ubiosDNSMasqConfigPath     = "/run/dnsmasq.conf.d/zzzctrld.conf"
+	toggleContentFilteringLink = "https://community.ui.com/questions/UDM-Pro-disable-enable-DNS-filtering/e2cc4060-e56a-4139-b200-62d7f773ff8f"
 )
 
 func setupUbiOS() error {
@@ -20,7 +25,7 @@ func setupUbiOS() error {
 		return err
 	}
 	// Restart dnsmasq service.
-	if err := ubiosRestartDNSMasq(); err != nil {
+	if err := restartDNSMasq(); err != nil {
 		return err
 	}
 	return nil
@@ -32,13 +37,17 @@ func cleanupUbiOS() error {
 		return err
 	}
 	// Restart dnsmasq service.
-	if err := ubiosRestartDNSMasq(); err != nil {
+	if err := restartDNSMasq(); err != nil {
 		return err
 	}
 	return nil
 }
 
 func postInstallUbiOS() error {
+	// See comment in postInstallEdgeOS.
+	if contentFilteringEnabled() {
+		return errContentFilteringEnabled
+	}
 	return nil
 }
 
@@ -57,3 +66,8 @@ func ubiosRestartDNSMasq() error {
 	}
 	return proc.Kill()
 }
+
+func contentFilteringEnabled() bool {
+	st, err := os.Stat("/run/dnsfilter/dnsfilter")
+	return err == nil && !st.IsDir()
+}

net.go

@@ -0,0 +1,46 @@
+package ctrld
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"tailscale.com/logtail/backoff"
+
+	ctrldnet "github.com/Control-D-Inc/ctrld/internal/net"
+)
+
+var (
+	hasIPv6Once   sync.Once
+	ipv6Available atomic.Bool
+)
+
+func hasIPv6() bool {
+	hasIPv6Once.Do(func() {
+		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+		defer cancel()
+		val := ctrldnet.IPv6Available(ctx)
+		ipv6Available.Store(val)
+		go probingIPv6(val)
+	})
+	return ipv6Available.Load()
+}
+
+// TODO(cuonglm): doing poll check natively for supported platforms.
+func probingIPv6(old bool) {
+	b := backoff.NewBackoff("probingIPv6", func(format string, args ...any) {}, 30*time.Second)
+	bCtx := context.Background()
+	for {
+		func() {
+			ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+			defer cancel()
+			cur := ctrldnet.IPv6Available(ctx)
+			if ipv6Available.CompareAndSwap(old, cur) {
+				old = cur
+			}
+		}()
+		b.BackOff(bCtx, errors.New("no change"))
+	}
+}

resolver.go

@@ -12,11 +12,17 @@ import (
 )
 
 const (
-	ResolverTypeDOH    = "doh"
+	// ResolverTypeDOH specifies DoH resolver.
-	ResolverTypeDOH3   = "doh3"
+	ResolverTypeDOH = "doh"
-	ResolverTypeDOT    = "dot"
+	// ResolverTypeDOH3 specifies DoH3 resolver.
-	ResolverTypeDOQ    = "doq"
+	ResolverTypeDOH3 = "doh3"
-	ResolverTypeOS     = "os"
+	// ResolverTypeDOT specifies DoT resolver.
+	ResolverTypeDOT = "dot"
+	// ResolverTypeDOQ specifies DoQ resolver.
+	ResolverTypeDOQ = "doq"
+	// ResolverTypeOS specifies OS resolver.
+	ResolverTypeOS = "os"
+	// ResolverTypeLegacy specifies legacy resolver.
 	ResolverTypeLegacy = "legacy"
 )
 
@@ -125,7 +131,14 @@ func (r *legacyResolver) Resolve(ctx context.Context, msg *dns.Msg) (*dns.Msg, e
 		Net:    udpNet,
 		Dialer: dialer,
 	}
-	answer, _, err := dnsClient.ExchangeContext(ctx, msg, r.uc.Endpoint)
+	endpoint := r.uc.Endpoint
+	if r.uc.BootstrapIP != "" {
+		dnsClient.Net = "udp"
+		_, port, _ := net.SplitHostPort(endpoint)
+		endpoint = net.JoinHostPort(r.uc.BootstrapIP, port)
+	}
+
+	answer, _, err := dnsClient.ExchangeContext(ctx, msg, endpoint)
 	return answer, err
 }
 
@@ -194,3 +207,17 @@ func lookupIP(domain string, timeout int, withBootstrapDNS bool) (ips []string)
 	}
 	return ips
 }
+
+// NewBootstrapResolver returns an OS resolver, which use following nameservers:
+//
+//   - ControlD bootstrap DNS server.
+//   - Gateway IP address (depends on OS).
+//   - Input servers.
+func NewBootstrapResolver(servers ...string) Resolver {
+	resolver := &osResolver{nameservers: nameservers()}
+	resolver.nameservers = append([]string{net.JoinHostPort(bootstrapDNS, "53")}, resolver.nameservers...)
+	for _, ns := range servers {
+		resolver.nameservers = append([]string{net.JoinHostPort(ns, "53")}, resolver.nameservers...)
+	}
+	return resolver
+}