Add option to prefer IPv6

build.gradle

@@ -150,8 +150,8 @@ android {
     defaultConfig {
         minSdkVersion 23
         targetSdkVersion 34
-        versionCode 180
+        versionCode 181
-        versionName "2.0.3"
+        versionName "2.0.4"
         applicationId "de.monocles.chat"
         def appName = "monocles chat"
         resValue "string", "app_name", appName

src/main/java/eu/siacs/conversations/AppSettings.java

@@ -52,6 +52,7 @@ public class AppSettings {
     private static final String ACCEPT_INVITES_FROM_STRANGERS = "accept_invites_from_strangers";
     private static final String INSTALLATION_ID = "im.conversations.android.install_id";
     public static final String SECURE_TLS = "secure_tls";
+    public static final String PREFER_IPV6 = "prefer_ipv6";
 
     private final Context context;
 
@@ -128,6 +129,10 @@ public class AppSettings {
         return getBooleanPreference(SECURE_TLS, R.bool.secure_tls);
     }
 
+    public boolean preferIPv6() {
+        return getBooleanPreference(PREFER_IPV6, R.bool.prefer_ipv6);
+    }
+
     public boolean isCallIntegration() {
         return getBooleanPreference(CALL_INTEGRATION, R.bool.call_integration);
     }

src/main/java/eu/siacs/conversations/ui/fragment/settings/ConnectionSettingsFragment.java

@@ -88,7 +88,7 @@ public class ConnectionSettingsFragment extends XmppPreferenceFragment {
                 reconnectAccounts();
                 requireService().reinitializeMuclumbusService();
             }
-            case AppSettings.SHOW_CONNECTION_OPTIONS -> {
+            case AppSettings.SHOW_CONNECTION_OPTIONS, AppSettings.PREFER_IPV6 -> {
                 reconnectAccounts();
             }
         }

src/main/java/eu/siacs/conversations/utils/Resolver.java

@@ -20,6 +20,7 @@ import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.MoreExecutors;
 
+import eu.siacs.conversations.AppSettings;
 import eu.siacs.conversations.Config;
 import eu.siacs.conversations.Conversations;
 import eu.siacs.conversations.xmpp.Jid;
@@ -38,6 +39,7 @@ import org.minidns.record.SRV;
 
 import java.io.IOException;
 import java.net.Inet4Address;
+import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
@@ -86,11 +88,21 @@ public class Resolver {
                         if (left.ip == null && right.ip == null) {
                             return 0;
                         } else if (left.ip != null && right.ip != null) {
-                            if (left.ip instanceof Inet4Address
+                            final var appSettings = new AppSettings(Conversations.getContext());
-                                    && right.ip instanceof Inet4Address) {
+                            if (appSettings.preferIPv6()) {
-                                return 0;
+                                if (left.ip instanceof Inet6Address
+                                        && right.ip instanceof Inet6Address) {
+                                    return 0;
+                                } else {
+                                    return left.ip instanceof Inet6Address ? -1 : 1;
+                                }
                             } else {
-                                return left.ip instanceof Inet4Address ? -1 : 1;
+                                if (left.ip instanceof Inet4Address
+                                        && right.ip instanceof Inet4Address) {
+                                    return 0;
+                                } else {
+                                    return left.ip instanceof Inet4Address ? -1 : 1;
+                                }
                             }
                         } else {
                             return left.ip != null ? -1 : 1;

src/main/res/drawable/rounded_commit_24.xml

@@ -0,0 +1,5 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android" android:height="24dp" android:tint="?colorControlNormal" android:viewportHeight="960" android:viewportWidth="960" android:width="24dp">
+      
+    <path android:fillColor="@android:color/white" android:pathData="M480,680Q407,680 352.5,634.5Q298,589 284,520L120,520Q103,520 91.5,508.5Q80,497 80,480Q80,463 91.5,451.5Q103,440 120,440L284,440Q298,371 352.5,325.5Q407,280 480,280Q553,280 607.5,325.5Q662,371 676,440L840,440Q857,440 868.5,451.5Q880,463 880,480Q880,497 868.5,508.5Q857,520 840,520L676,520Q662,589 607.5,634.5Q553,680 480,680ZM480,600Q530,600 565,565Q600,530 600,480Q600,430 565,395Q530,360 480,360Q430,360 395,395Q360,430 360,480Q360,530 395,565Q430,600 480,600Z"/>
+    
+</vector>

src/main/res/values/bools.xml

@@ -12,4 +12,5 @@
     <bool name="showtextformatting">false</bool>
     <bool name="app_lock_enabled">false</bool>
     <bool name="secure_tls">false</bool>
+    <bool name="prefer_ipv6">false</bool>
 </resources>

src/main/res/values/strings.xml

@@ -1404,4 +1404,6 @@
     <string name="pref_hide_media_summary">Hide received and sent media from system gallery views</string>
     <string name="pref_secure_tls_summary">Use only securest TLS ciphers including post quantum key agreement if available on server</string>
     <string name="pref_secure_tls">Use secure TLS Ciphers only</string>
+    <string name="pref_prefer_ipv6_summary">Prefers IPv6 when connecting</string>
+    <string name="pref_prefer_ipv6">Prefer IPv6</string>
 </resources>

src/main/res/xml/preferences_connection.xml

@@ -14,6 +14,12 @@
             android:key="use_tor"
             android:summary="@string/pref_use_tor_summary"
             android:title="@string/pref_use_tor" />
+        <SwitchPreferenceCompat
+            android:defaultValue="@bool/prefer_ipv6"
+            android:icon="@drawable/rounded_commit_24"
+            android:key="prefer_ipv6"
+            android:summary="@string/pref_prefer_ipv6_summary"
+            android:title="@string/pref_prefer_ipv6" />
         <EditTextPreference
             android:defaultValue="@string/default_dns_server_ipv4"
             android:icon="@drawable/outline_dns_24"