Add `CustomDns.replaceDnsServer` method

1 files changed, 20 insertions, 0 deletions

diff --git a/android/src/main/kotlin/net/mullvad/mullvadvpn/service/CustomDns.kt b/android/src/main/kotlin/net/mullvad/mullvadvpn/service/CustomDns.kt
index 3bd1ae8cc8..9b41877f4c 100644
--- a/android/src/main/kotlin/net/mullvad/mullvadvpn/service/CustomDns.kt
+++ b/android/src/main/kotlin/net/mullvad/mullvadvpn/service/CustomDns.kt
@@ -56,6 +56,26 @@ class CustomDns(val daemon: MullvadDaemon, val settingsListener: SettingsListene
         return false
     }
 
+    fun replaceDnsServer(oldServer: InetAddress, newServer: InetAddress): Boolean {
+        synchronized(this) {
+            if (oldServer == newServer) {
+                return true
+            } else if (!dnsServers.contains(newServer)) {
+                val index = dnsServers.indexOf(oldServer)
+
+                if (index >= 0) {
+                    dnsServers.removeAt(index)
+                    dnsServers.add(index, newServer)
+                    changeDnsOptions(enabled, dnsServers)
+
+                    return true
+                }
+            }
+        }
+
+        return false
+    }
+
     fun removeDnsServer(server: InetAddress) {
         synchronized(this) {
             if (dnsServers.remove(server)) {