feat(vpn): run WaitForDNS before querying the public ip address

- Fix #2325 better

internal/vpn/tunnelup.go

@@ -2,9 +2,8 @@ package vpn
 
 import (
 	"context"
-	"strings"
-	"time"
 
+	"github.com/qdm12/dns/v2/pkg/check"
 	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/version"
 )
@@ -31,9 +30,17 @@ func (l *Loop) onTunnelUp(ctx context.Context, data tunnelUpData) {
 
 	if *l.dnsLooper.GetSettings().DoT.Enabled {
 		_, _ = l.dnsLooper.ApplyStatus(ctx, constants.Running)
+	} else {
+		err := check.WaitForDNS(ctx, check.Settings{})
+		if err != nil {
+			l.logger.Error("waiting for DNS to be ready: " + err.Error())
+		}
 	}
 
-	l.fetchPublicIPWithRetry(ctx)
+	err := l.publicip.RunOnce(ctx)
+	if err != nil {
+		l.logger.Error("getting public IP address information: " + err.Error())
+	}
 
 	if l.versionInfo {
 		l.versionInfo = false // only get the version information once
@@ -45,31 +52,8 @@ func (l *Loop) onTunnelUp(ctx context.Context, data tunnelUpData) {
 		}
 	}
 
-	err := l.startPortForwarding(data)
+	err = l.startPortForwarding(data)
 	if err != nil {
 		l.logger.Error(err.Error())
 	}
 }
-
-func (l *Loop) fetchPublicIPWithRetry(ctx context.Context) {
-	for {
-		err := l.publicip.RunOnce(ctx)
-		if err == nil {
-			return
-		}
-
-		l.logger.Error("getting public IP address information: " + err.Error())
-		if !strings.HasSuffix(err.Error(), "read: connection refused") {
-			return
-		}
-
-		// Retry mechanism asked in https://github.com/qdm12/gluetun/issues/2325
-		const retryPeriod = 2 * time.Second
-		l.logger.Infof("retrying public IP address information fetch in %s", retryPeriod)
-		timer := time.NewTimer(retryPeriod)
-		select {
-		case <-ctx.Done():
-		case <-timer.C:
-		}
-	}
-}