all: refactor router code to use interface

So the code is more modular, easier to read/maintain.

internal/router/tomato/tomato.go

@@ -0,0 +1,131 @@
+package tomato
+
+import (
+	"fmt"
+	"os/exec"
+
+	"github.com/Control-D-Inc/ctrld"
+	"github.com/Control-D-Inc/ctrld/internal/router/dnsmasq"
+	"github.com/Control-D-Inc/ctrld/internal/router/ntp"
+	"github.com/Control-D-Inc/ctrld/internal/router/nvram"
+	"github.com/kardianos/service"
+)
+
+const (
+	Name = "freshtomato"
+
+	tomatoDnsCryptProxySvcName = "dnscrypt-proxy"
+	tomatoStubbySvcName        = "stubby"
+	tomatoDNSMasqSvcName       = "dnsmasq"
+)
+
+var nvramKvMap = 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
+}
+
+type FreshTomato struct {
+	cfg *ctrld.Config
+}
+
+// New returns a router.Router for configuring/setup/run ctrld on Ubios routers.
+func New(cfg *ctrld.Config) *FreshTomato {
+	return &FreshTomato{cfg: cfg}
+}
+
+func (f *FreshTomato) ConfigureService(config *service.Config) error {
+	return nil
+}
+
+func (f *FreshTomato) Install(_ *service.Config) error {
+	return nil
+}
+
+func (f *FreshTomato) Uninstall(_ *service.Config) error {
+	return nil
+}
+
+func (f *FreshTomato) PreRun() error {
+	_ = f.Cleanup()
+	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" {
+		return nil
+	}
+
+	data, err := dnsmasq.ConfTmpl(dnsmasq.ConfigContentTmpl, f.cfg)
+	if err != nil {
+		return err
+	}
+	nvramKvMap["dnsmasq_custom"] = data
+	if err := nvram.SetKV(nvramKvMap, nvram.CtrldSetupKey); 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 (f *FreshTomato) Cleanup() error {
+	if val, _ := nvram.Run("get", nvram.CtrldSetupKey); val == "1" {
+		nvramKvMap["dnsmasq_custom"] = ""
+		// Restore old configs.
+		if err := nvram.Restore(nvramKvMap, nvram.CtrldSetupKey); 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
+}
+
+func restartDNSMasq() error {
+	return tomatoRestartService(tomatoDNSMasqSvcName)
+}