DNS retry custom

app/src/main/java/eu/faircode/email/DnsHelper.java

@@ -55,6 +55,7 @@ import org.minidns.record.Record;
 import org.minidns.record.SRV;
 import org.minidns.record.TXT;
 import org.minidns.source.AbstractDnsDataSource;
+import org.minidns.source.DnsDataSource;
 import org.minidns.util.MultipleIoException;
 
 import java.io.ByteArrayOutputStream;
@@ -184,6 +185,8 @@ public class DnsHelper {
         ResolverApi resolver = DnssecResolverApi.INSTANCE;
         AbstractDnsClient client = resolver.getClient();
 
+        DnsDataSource dataSource = client.getDataSource();
+
         if (false) {
             String private_dns = ConnectionHelper.getPrivateDnsServerName(context);
             Log.w("DNS private=" + private_dns);
@@ -199,7 +202,17 @@ public class DnsHelper {
             ((DnssecClient) client).setUseHardcodedDnsServers(false);
 
         Log.i("DNS query name=" + type + ":" + name);
-        ResolverResult<? extends Data> data = resolver.resolve(name, clazz);
+        ResolverResult<? extends Data> data;
+        try {
+            data = resolver.resolve(name, clazz);
+        } catch (Throwable ex) {
+            Log.w(ex);
+            if (dataSource == null || dataSource == client.getDataSource())
+                throw ex;
+            Log.i("DNS retry custom");
+            client.setDataSource(dataSource);
+            data = resolver.resolve(name, clazz);
+        }
         Log.i("DNS resolved name=" + type + ":" + name +
                 " success=" + data.wasSuccessful() +
                 " rcode=" + data.getResponseCode());
@@ -207,8 +220,7 @@ public class DnsHelper {
         try {
             data.throwIfErrorResponse();
         } catch (Throwable ex) {
-            Log.e("DNS error message=" + ex.getMessage());
+            Log.w("DNS error message=" + ex.getMessage());
-            Log.e(ex);
             throw ex;
         }