hotfix(dns): always run and use built-in DNS server

- start DNS server before healthcheck
- do not fallback to plaintext anymore
- allow to use plain addresses with a port different than 53, system-wide
- do not wait for the DNS server and rely on healtcheck only

internal/dns/plaintext.go

@@ -1,37 +0,0 @@
-package dns
-
-import (
-	"net/netip"
-	"time"
-
-	"github.com/qdm12/dns/v2/pkg/nameserver"
-)
-
-func (l *Loop) useUnencryptedDNS(fallback bool) {
-	settings := l.GetSettings()
-
-	targetIP := settings.GetFirstPlaintextIPv4()
-
-	if fallback {
-		l.logger.Info("falling back on plaintext DNS at address " + targetIP.String())
-	} else {
-		l.logger.Info("using plaintext DNS at address " + targetIP.String())
-	}
-
-	const dialTimeout = 3 * time.Second
-	const defaultDNSPort = 53
-	settingsInternalDNS := nameserver.SettingsInternalDNS{
-		AddrPort: netip.AddrPortFrom(targetIP, defaultDNSPort),
-		Timeout:  dialTimeout,
-	}
-	nameserver.UseDNSInternally(settingsInternalDNS)
-
-	settingsSystemWide := nameserver.SettingsSystemDNS{
-		IPs:        []netip.Addr{targetIP},
-		ResolvPath: l.resolvConf,
-	}
-	err := nameserver.UseDNSSystemWide(settingsSystemWide)
-	if err != nil {
-		l.logger.Error(err.Error())
-	}
-}

internal/dns/run.go

@@ -18,9 +18,6 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 		return
 	}
 
-	const fallback = false
-	l.useUnencryptedDNS(fallback)
-
 	select {
 	case <-l.start:
 	case <-ctx.Done():
@@ -83,8 +80,6 @@ func (l *Loop) runWait(ctx context.Context, runError <-chan error) (exitLoop boo
 		case <-l.stop:
 			l.userTrigger = true
 			l.logger.Info("stopping")
-			const fallback = false
-			l.useUnencryptedDNS(fallback)
 			l.stopServer()
 			l.stopped <- struct{}{}
 		case <-l.start:
@@ -93,8 +88,6 @@ func (l *Loop) runWait(ctx context.Context, runError <-chan error) (exitLoop boo
 			return false
 		case err := <-runError: // unexpected error
 			l.statusManager.SetStatus(constants.Crashed)
-			const fallback = true
-			l.useUnencryptedDNS(fallback)
 			l.logAndWait(ctx, err)
 			return false
 		}

internal/dns/setup.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 
-	"github.com/qdm12/dns/v2/pkg/check"
 	"github.com/qdm12/dns/v2/pkg/middlewares/filter/update"
 	"github.com/qdm12/dns/v2/pkg/nameserver"
 	"github.com/qdm12/dns/v2/pkg/server"
@@ -44,11 +43,5 @@ func (l *Loop) setupServer(ctx context.Context, settings settings.DNS) (runError
 		l.logger.Error(err.Error())
 	}
 
-	err = check.WaitForDNS(ctx, check.Settings{})
-	if err != nil {
-		l.stopServer()
-		return nil, err
-	}
-
 	return runError, nil
 }

internal/vpn/tunnelup.go

@@ -76,6 +76,8 @@ func (l *Loop) onTunnelUp(ctx, loopCtx context.Context, data tunnelUpData) {
 		}
 	}
 
+	_, _ = l.dnsLooper.ApplyStatus(ctx, constants.Running)
+
 	icmpTargetIPs := l.healthSettings.ICMPTargetIPs
 	if len(icmpTargetIPs) == 1 && icmpTargetIPs[0].IsUnspecified() {
 		icmpTargetIPs = []netip.Addr{data.serverIP}
@@ -101,8 +103,6 @@ func (l *Loop) onTunnelUp(ctx, loopCtx context.Context, data tunnelUpData) {
 	// to start monitoring health and auto-healing.
 	go l.collectHealthErrors(ctx, loopCtx, healthErrCh)
 
-	_, _ = l.dnsLooper.ApplyStatus(ctx, constants.Running)
-
 	err = l.publicip.RunOnce(ctx)
 	if err != nil {
 		l.logger.Error("getting public IP address information: " + err.Error())