all: rework fetching/generating config in cd mode

Config fetching/generating in cd mode is currently weird, error prone,
and easy for user to break ctrld when using custom config.

This commit reworks the flow:

 - Fetching config from Control D API.
 - No custom config, use the current default config.
 - If custom config presents, but there's no listener, use 0.0.0.0:53.
 - Try listening on current ip+port config, if ok, ctrld could be a
   direct listener with current setup, moving on.
 - If failed, trying 127.0.0.1:53.
 - If failed, trying current ip + port 5354
 - If still failed, pick a random ip:port pair, retry until listening ok.

With this flow, thing is more predictable/stable, and help removing the
Config interface for router.

internal/dns/nm.go

@@ -267,5 +267,5 @@ func (m *nmManager) Close() error {
 }
 
 func (m *nmManager) Mode() string {
-	return "network-maanger"
+	return "network-manager"
 }

internal/router/ddwrt/ddwrt.go

@@ -57,12 +57,6 @@ func (d *Ddwrt) PreRun() error {
 	return ntp.Wait()
 }
 
-func (d *Ddwrt) Configure() error {
-	d.cfg.Listener["0"].IP = "127.0.0.1"
-	d.cfg.Listener["0"].Port = 5354
-	return nil
-}
-
 func (d *Ddwrt) Setup() error {
 	// Already setup.
 	if val, _ := nvram.Run("get", nvram.CtrldSetupKey); val == "1" {

internal/router/dnsmasq/dnsmasq.go

@@ -1,6 +1,7 @@
 package dnsmasq
 
 import (
+	"errors"
 	"html/template"
 	"net"
 	"path/filepath"
@@ -60,15 +61,20 @@ type Upstream struct {
 }
 
 func ConfTmpl(tmplText string, cfg *ctrld.Config) (string, error) {
-	upstreams := make([]Upstream, 0, len(cfg.Listener))
-	for _, listener := range cfg.Listener {
-		upstreams = append(upstreams, Upstream{Ip: listener.IP, Port: listener.Port})
+	listener := cfg.FirstListener()
+	if listener == nil {
+		return "", errors.New("missing listener")
 	}
+	ip := listener.IP
+	if ip == "0.0.0.0" || ip == "::" || ip == "" {
+		ip = "127.0.0.1"
+	}
+	upstreams := []Upstream{{Ip: ip, Port: listener.Port}}
 	return confTmpl(tmplText, upstreams, cfg.HasUpstreamSendClientInfo())
 }
 
 func FirewallaConfTmpl(tmplText string, cfg *ctrld.Config) (string, error) {
-	if lc := cfg.Listener["0"]; lc != nil && lc.IP == "0.0.0.0" {
+	if lc := cfg.FirstListener(); lc != nil && (lc.IP == "0.0.0.0" || lc.IP == "") {
 		return confTmpl(tmplText, firewallaUpstreams(lc.Port), cfg.HasUpstreamSendClientInfo())
 	}
 	return ConfTmpl(tmplText, cfg)

internal/router/dummy.go

@@ -4,10 +4,6 @@ import "github.com/kardianos/service"
 
 type dummy struct{}
 
-func NewDummyRouter() Router {
-	return &dummy{}
-}
-
 func (d *dummy) ConfigureService(_ *service.Config) error {
 	return nil
 }

internal/router/edgeos/edgeos.go

@@ -61,12 +61,6 @@ func (e *EdgeOS) PreRun() error {
 	return nil
 }
 
-func (e *EdgeOS) Configure() error {
-	e.cfg.Listener["0"].IP = "127.0.0.1"
-	e.cfg.Listener["0"].Port = 5354
-	return nil
-}
-
 func (e *EdgeOS) Setup() error {
 	if e.isUSG {
 		return e.setupUSG()

internal/router/firewalla/firewalla.go

@@ -53,12 +53,6 @@ func (f *Firewalla) PreRun() error {
 	return nil
 }
 
-func (f *Firewalla) Configure() error {
-	f.cfg.Listener["0"].IP = "0.0.0.0"
-	f.cfg.Listener["0"].Port = 5354
-	return nil
-}
-
 func (f *Firewalla) Setup() error {
 	data, err := dnsmasq.FirewallaConfTmpl(dnsmasq.ConfigContentTmpl, f.cfg)
 	if err != nil {

internal/router/merlin/merlin.go

@@ -48,12 +48,6 @@ func (m *Merlin) PreRun() error {
 	return ntp.Wait()
 }
 
-func (m *Merlin) Configure() error {
-	m.cfg.Listener["0"].IP = "127.0.0.1"
-	m.cfg.Listener["0"].Port = 5354
-	return nil
-}
-
 func (m *Merlin) Setup() error {
 	buf, err := os.ReadFile(dnsmasq.MerlinPostConfPath)
 	// Already setup.

internal/router/openwrt/openwrt.go

@@ -48,12 +48,6 @@ func (o *Openwrt) PreRun() error {
 	return nil
 }
 
-func (o *Openwrt) Configure() error {
-	o.cfg.Listener["0"].IP = "127.0.0.1"
-	o.cfg.Listener["0"].Port = 5354
-	return nil
-}
-
 func (o *Openwrt) Setup() error {
 	// Delete dnsmasq port if set.
 	if _, err := uci("delete", "dhcp.@dnsmasq[0].port"); err != nil && !errors.Is(err, errUCIEntryNotFound) {

internal/router/pfsense/pfsense.go

@@ -54,6 +54,14 @@ func (p *Pfsense) ConfigureService(svc *service.Config) error {
 }
 
 func (p *Pfsense) Install(config *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, p.svcName)
+	newname := filepath.Join(rcPath, p.svcName+".sh")
+	_ = os.Remove(newname)
+	if err := os.Symlink(oldname, newname); err != nil {
+		return fmt.Errorf("os.Symlink: %w", err)
+	}
 	return nil
 }
 
@@ -62,16 +70,7 @@ func (p *Pfsense) Uninstall(config *service.Config) error {
 }
 
 func (p *Pfsense) PreRun() error {
-	return nil
-}
-
-func (p *Pfsense) Configure() error {
-	p.cfg.Listener["0"].IP = "127.0.0.1"
-	p.cfg.Listener["0"].Port = 53
-	return nil
-}
-
-func (p *Pfsense) Setup() error {
+	// TODO: remove this hacky solution.
 	// If Pfsense is in DNS Resolver mode, ensure no unbound processes running.
 	_ = exec.Command("killall", "unbound").Run()
 
@@ -80,6 +79,10 @@ func (p *Pfsense) Setup() error {
 	return nil
 }
 
+func (p *Pfsense) Setup() error {
+	return nil
+}
+
 func (p *Pfsense) Cleanup() error {
 	if err := os.Remove(filepath.Join(rcPath, p.svcName+".sh")); err != nil {
 		return fmt.Errorf("os.Remove: %w", err)

internal/router/router.go

@@ -27,15 +27,9 @@ type Service interface {
 	Uninstall(*service.Config) error
 }
 
-// Config is the interface to manage ctrld config on router.
-type Config interface {
-	Configure() error
-}
-
 // Router is the interface for managing ctrld running on router.
 type Router interface {
 	Service
-	Config
 
 	PreRun() error
 	Setup() error
@@ -64,7 +58,7 @@ func New(cfg *ctrld.Config) Router {
 	case firewalla.Name:
 		return firewalla.New(cfg)
 	}
-	return NewDummyRouter()
+	return &dummy{}
 }
 
 // IsGLiNet reports whether the router is an GL.iNet router.
@@ -94,38 +88,6 @@ type router struct {
 	sendClientInfo bool
 }
 
-// IsSupported reports whether the given platform is supported by ctrld.
-func IsSupported(platform string) bool {
-	switch platform {
-	case ddwrt.Name,
-		edgeos.Name,
-		firewalla.Name,
-		merlin.Name,
-		openwrt.Name,
-		pfsense.Name,
-		synology.Name,
-		tomato.Name,
-		ubios.Name:
-		return true
-	}
-	return false
-}
-
-// SupportedPlatforms return all platforms that can be configured to run with ctrld.
-func SupportedPlatforms() []string {
-	return []string{
-		ddwrt.Name,
-		edgeos.Name,
-		firewalla.Name,
-		merlin.Name,
-		openwrt.Name,
-		pfsense.Name,
-		synology.Name,
-		tomato.Name,
-		ubios.Name,
-	}
-}
-
 // Name returns name of the router platform.
 func Name() string {
 	if r := routerPlatform.Load(); r != nil {

internal/router/synology/synology.go

@@ -43,12 +43,6 @@ func (s *Synology) PreRun() error {
 	return nil
 }
 
-func (s *Synology) Configure() error {
-	s.cfg.Listener["0"].IP = "127.0.0.1"
-	s.cfg.Listener["0"].Port = 5354
-	return nil
-}
-
 func (s *Synology) Setup() error {
 	data, err := dnsmasq.ConfTmpl(dnsmasq.ConfigContentTmpl, s.cfg)
 	if err != nil {

internal/router/tomato/tomato.go

@@ -52,12 +52,6 @@ func (f *FreshTomato) PreRun() error {
 	return ntp.Wait()
 }
 
-func (f *FreshTomato) Configure() error {
-	f.cfg.Listener["0"].IP = "127.0.0.1"
-	f.cfg.Listener["0"].Port = 5354
-	return nil
-}
-
 func (f *FreshTomato) Setup() error {
 	// Already setup.
 	if val, _ := nvram.Run("get", nvram.CtrldSetupKey); val == "1" {

internal/router/ubios/ubios.go

@@ -46,12 +46,6 @@ func (u *Ubios) PreRun() error {
 	return nil
 }
 
-func (u *Ubios) Configure() error {
-	u.cfg.Listener["0"].IP = "127.0.0.1"
-	u.cfg.Listener["0"].Port = 5354
-	return nil
-}
-
 func (u *Ubios) Setup() error {
 	data, err := dnsmasq.ConfTmpl(dnsmasq.ConfigContentTmpl, u.cfg)
 	if err != nil {