From f232a6f4c9219cab431005ebacc7bda3cdcd64fb Mon Sep 17 00:00:00 2001
From: Diego Romar <18450339+doromaraujo@users.noreply.github.com>
Date: Mon, 22 Sep 2025 08:58:41 -0300
Subject: [PATCH] Add check on current looper when adding dns to
 VPNService.builder

---
 .../java/io/netbird/client/tool/IFace.java    | 36 +++++++++++--------
 1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/tool/src/main/java/io/netbird/client/tool/IFace.java b/tool/src/main/java/io/netbird/client/tool/IFace.java
index 918d2ac..e41a280 100644
--- a/tool/src/main/java/io/netbird/client/tool/IFace.java
+++ b/tool/src/main/java/io/netbird/client/tool/IFace.java
@@ -104,25 +104,33 @@ class IFace implements TunAdapter {
             return;
         }
 
-        CountDownLatch latch = new CountDownLatch(1);
+        if (Looper.myLooper() != Looper.getMainLooper()) {
+            CountDownLatch latch = new CountDownLatch(1);
 
-        // ConnectivityManager must to run on the main thread instead of a Go routine
-        new Handler(Looper.getMainLooper()).post(() -> {
-            DNSWatch dnsWatch = new DNSWatch(vpnService);
+            // ConnectivityManager must to run on the main thread instead of a Go routine
+            new Handler(Looper.getMainLooper()).post(() -> {
+                addDnsServer(builder, dns);
 
-            if (!dnsWatch.isPrivateDnsActive()) {
-                builder.addDnsServer(dns);
-            } else {
-                Log.d(LOGTAG, "ignore DNS because private dns is active");
+                latch.countDown();
+            });
+
+            try {
+                latch.await(); // Will block the current thread until countDown() is called
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
             }
+        } else {
+            addDnsServer(builder, dns);
+        }
+    }
 
-            latch.countDown();
-        });
+    private void addDnsServer(VpnService.Builder builder, String dns) {
+        DNSWatch dnsWatch = new DNSWatch(vpnService);
 
-        try {
-            latch.await(); // Will block the current thread until countDown() is called
-        } catch (InterruptedException e) {
-            Thread.currentThread().interrupt();
+        if (!dnsWatch.isPrivateDnsActive()) {
+            builder.addDnsServer(dns);
+        } else {
+            Log.d(LOGTAG, "ignore DNS because private dns is active");
         }
     }