all: fix OS resolver looping issue on Windows

By making dnsFromAdapter ignores DNS server which is the same IP address
of the adapter.

While at it, also changes OS resolver to use ctrld bootstrap DNS only if
there's no available nameservers.

cmd/cli/cli.go

@@ -507,7 +507,7 @@ func initCLI() {
 			iface = runningIface(s)
 			tasks := []task{
 				{s.Stop, false},
-				{func() error { p.resetDNS(); return nil }, false},
+				{func() error { resetDnsNoLog(p); return nil }, false},
 				{s.Start, true},
 			}
 			if doTasks(tasks) {
@@ -887,7 +887,10 @@ NOTE: Uninstalling will set DNS to values provided by DHCP.`,
 			sc := &service.Config{}
 			*sc = *svcConfig
 			sc.Executable = bin
-			s, err := newService(&prog{}, sc)
+			readConfig(false)
+			v.Unmarshal(&cfg)
+			p := &prog{router: router.New(&cfg, runInCdMode())}
+			s, err := newService(p, sc)
 			if err != nil {
 				mainLog.Load().Error().Msg(err.Error())
 				return
@@ -931,6 +934,7 @@ NOTE: Uninstalling will set DNS to values provided by DHCP.`,
 				}
 				tasks := []task{
 					{s.Stop, false},
+					{func() error { resetDnsNoLog(p); return nil }, false},
 					{s.Start, false},
 				}
 				if doTasks(tasks) {
@@ -2541,3 +2545,11 @@ func runningIface(s service.Service) string {
 	}
 	return ""
 }
+
+// resetDnsNoLog performs resetting DNS with logging disable.
+func resetDnsNoLog(p *prog) {
+	lvl := zerolog.GlobalLevel()
+	zerolog.SetGlobalLevel(zerolog.Disabled)
+	p.resetDNS()
+	zerolog.SetGlobalLevel(lvl)
+}