internal/router: do not disable cache on EdgeOS

The dnsmasq cache-size setting on EdgeOS could be re-generated anytime
by vyatta router/dhcp components. This conflicts with setting generated
by ctrld, causing dnsmasq fails to start.

It's better to keep dnsmasq cache enabled on EdgeOS, we can turn it off
again once we find a reliable way to control cache-size setting.

internal/router/dnsmasq/dnsmasq.go

@@ -22,7 +22,9 @@ server={{ .IP }}#{{ .Port }}
 add-mac
 add-subnet=32,128
 {{- end}}
+{{- if .CacheDisabled}}
 cache-size=0
+{{- end}}
 `
 
 const MerlinPostConfPath = "/jffs/scripts/dnsmasq.postconf"
@@ -71,6 +73,10 @@ type Upstream struct {
 }
 
 func ConfTmpl(tmplText string, cfg *ctrld.Config) (string, error) {
+	return ConfTmplWitchCacheDisabled(tmplText, cfg, true)
+}
+
+func ConfTmplWitchCacheDisabled(tmplText string, cfg *ctrld.Config, cacheDisabled bool) (string, error) {
 	listener := cfg.FirstListener()
 	if listener == nil {
 		return "", errors.New("missing listener")
@@ -80,24 +86,26 @@ func ConfTmpl(tmplText string, cfg *ctrld.Config) (string, error) {
 		ip = "127.0.0.1"
 	}
 	upstreams := []Upstream{{IP: ip, Port: listener.Port}}
-	return confTmpl(tmplText, upstreams, cfg.HasUpstreamSendClientInfo())
+	return confTmpl(tmplText, upstreams, cfg.HasUpstreamSendClientInfo(), cacheDisabled)
 }
 
 func FirewallaConfTmpl(tmplText string, cfg *ctrld.Config) (string, error) {
 	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, firewallaUpstreams(lc.Port), cfg.HasUpstreamSendClientInfo(), true)
 	}
 	return ConfTmpl(tmplText, cfg)
 }
 
-func confTmpl(tmplText string, upstreams []Upstream, sendClientInfo bool) (string, error) {
+func confTmpl(tmplText string, upstreams []Upstream, sendClientInfo, cacheDisabled bool) (string, error) {
 	tmpl := template.Must(template.New("").Parse(tmplText))
 	var to = &struct {
 		SendClientInfo bool
 		Upstreams      []Upstream
+		CacheDisabled  bool
 	}{
 		SendClientInfo: sendClientInfo,
 		Upstreams:      upstreams,
+		CacheDisabled:  cacheDisabled,
 	}
 	var sb strings.Builder
 	if err := tmpl.Execute(&sb, to); err != nil {

internal/router/edgeos/edgeos.go

@@ -8,19 +8,18 @@ import (
 	"os/exec"
 	"strings"
 
-	"github.com/Control-D-Inc/ctrld/internal/router/dnsmasq"
+	"github.com/kardianos/service"
 
 	"github.com/Control-D-Inc/ctrld"
-	"github.com/kardianos/service"
+	"github.com/Control-D-Inc/ctrld/internal/router/dnsmasq"
 )
 
 const (
-	Name                           = "edgeos"
+	Name                       = "edgeos"
-	edgeOSDNSMasqDefaultConfigPath = "/etc/dnsmasq.conf"
+	edgeOSDNSMasqConfigPath    = "/etc/dnsmasq.d/dnsmasq-zzz-ctrld.conf"
-	edgeOSDNSMasqConfigPath        = "/etc/dnsmasq.d/dnsmasq-zzz-ctrld.conf"
+	usgDNSMasqConfigPath       = "/etc/dnsmasq.conf"
-	usgDNSMasqConfigPath           = "/etc/dnsmasq.conf"
+	usgDNSMasqBackupConfigPath = "/etc/dnsmasq.conf.bak"
-	usgDNSMasqBackupConfigPath     = "/etc/dnsmasq.conf.bak"
+	toggleContentFilteringLink = "https://community.ui.com/questions/UDM-Pro-disable-enable-DNS-filtering/e2cc4060-e56a-4139-b200-62d7f773ff8f"
-	toggleContentFilteringLink     = "https://community.ui.com/questions/UDM-Pro-disable-enable-DNS-filtering/e2cc4060-e56a-4139-b200-62d7f773ff8f"
 )
 
 var ErrContentFilteringEnabled = fmt.Errorf(`the "Content Filtering" feature" is enabled, which is conflicted with ctrld.\n
@@ -107,13 +106,10 @@ func (e *EdgeOS) setupUSG() error {
 		if strings.HasPrefix(line, "all-servers") {
 			continue
 		}
-		if strings.HasPrefix(line, "cache-size") {
-			continue
-		}
 		sb.WriteString(line)
 	}
 
-	data, err := dnsmasq.ConfTmpl(dnsmasq.ConfigContentTmpl, e.cfg)
+	data, err := dnsmasq.ConfTmplWitchCacheDisabled(dnsmasq.ConfigContentTmpl, e.cfg, false)
 	if err != nil {
 		return err
 	}
@@ -131,11 +127,7 @@ func (e *EdgeOS) setupUSG() error {
 }
 
 func (e *EdgeOS) setupUDM() error {
-	// Disable dnsmasq cache.
+	data, err := dnsmasq.ConfTmplWitchCacheDisabled(dnsmasq.ConfigContentTmpl, e.cfg, false)
-	if err := dnsmasq.DisableCache(edgeOSDNSMasqDefaultConfigPath); err != nil {
-		return err
-	}
-	data, err := dnsmasq.ConfTmpl(dnsmasq.ConfigContentTmpl, e.cfg)
 	if err != nil {
 		return err
 	}
@@ -161,10 +153,6 @@ func (e *EdgeOS) cleanupUSG() error {
 }
 
 func (e *EdgeOS) cleanupUDM() error {
-	// Enable dnsmasq cache.
-	if err := dnsmasq.EnableCache(edgeOSDNSMasqDefaultConfigPath); err != nil {
-		return err
-	}
 	// Remove the custom dnsmasq config
 	if err := os.Remove(edgeOSDNSMasqConfigPath); err != nil {
 		return fmt.Errorf("cleanupUDM: os.Remove: %w", err)