From b051aaf41ef82b67e9d780e8de1378993b906ee1 Mon Sep 17 00:00:00 2001
From: M66B <M66B@users.noreply.github.com>
Date: Tue, 27 Oct 2020 13:22:23 +0100
Subject: [PATCH] Added option to prefer IPv4

---
 .../main/java/eu/faircode/email/EmailService.java   | 12 ++++++++++++
 .../faircode/email/FragmentOptionsConnection.java   | 12 +++++++++++-
 .../java/eu/faircode/email/ServiceSynchronize.java  |  2 +-
 .../main/res/layout/fragment_options_connection.xml | 13 ++++++++++++-
 app/src/main/res/values/strings.xml                 |  1 +
 5 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/app/src/main/java/eu/faircode/email/EmailService.java b/app/src/main/java/eu/faircode/email/EmailService.java
index 6b34ce7e3c..0d5c1af9d4 100644
--- a/app/src/main/java/eu/faircode/email/EmailService.java
+++ b/app/src/main/java/eu/faircode/email/EmailService.java
@@ -431,6 +431,18 @@ public class EmailService implements AutoCloseable {
             //            new SocketConnectException("Debug", new IOException("Test"), host, port, 0));
 
             main = InetAddress.getByName(host);
+
+            SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
+            boolean prefer_ip4 = prefs.getBoolean("prefer_ip4", false);
+            if (prefer_ip4 && main instanceof Inet6Address) {
+                for (InetAddress iaddr : InetAddress.getAllByName(host))
+                    if (iaddr instanceof Inet4Address) {
+                        main = iaddr;
+                        EntityLog.log(context, "Preferring=" + main);
+                        break;
+                    }
+            }
+
             EntityLog.log(context, "Connecting to " + main);
             _connect(main, port, require_id, user, authenticator, factory);
         } catch (UnknownHostException ex) {
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptionsConnection.java b/app/src/main/java/eu/faircode/email/FragmentOptionsConnection.java
index 3255cf4482..fe764a4b02 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptionsConnection.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptionsConnection.java
@@ -58,13 +58,14 @@ public class FragmentOptionsConnection extends FragmentBase implements SharedPre
     private SwitchCompat swRoaming;
     private SwitchCompat swRlah;
     private EditText etTimeout;
+    private SwitchCompat swPreferIp4;
     private SwitchCompat swSslHarden;
     private Button btnManage;
     private TextView tvConnectionType;
     private TextView tvConnectionRoaming;
 
     private final static String[] RESET_OPTIONS = new String[]{
-            "metered", "download", "roaming", "rlah", "timeout", "ssl_harden"
+            "metered", "download", "roaming", "rlah", "timeout", "prefer_ip4", "ssl_harden"
     };
 
     @Override
@@ -82,6 +83,7 @@ public class FragmentOptionsConnection extends FragmentBase implements SharedPre
         swRoaming = view.findViewById(R.id.swRoaming);
         swRlah = view.findViewById(R.id.swRlah);
         etTimeout = view.findViewById(R.id.etTimeout);
+        swPreferIp4 = view.findViewById(R.id.swPreferIp4);
         swSslHarden = view.findViewById(R.id.swSslHarden);
         btnManage = view.findViewById(R.id.btnManage);
 
@@ -153,6 +155,13 @@ public class FragmentOptionsConnection extends FragmentBase implements SharedPre
             }
         });
 
+        swPreferIp4.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
+                prefs.edit().putBoolean("prefer_ip4", checked).apply();
+            }
+        });
+
         swSslHarden.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -266,6 +275,7 @@ public class FragmentOptionsConnection extends FragmentBase implements SharedPre
         etTimeout.setText(timeout == 0 ? null : Integer.toString(timeout));
         etTimeout.setHint(Integer.toString(EmailService.DEFAULT_CONNECT_TIMEOUT));
 
+        swPreferIp4.setChecked(prefs.getBoolean("prefer_ip4", false));
         swSslHarden.setChecked(prefs.getBoolean("ssl_harden", false));
     }
 
diff --git a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
index 465e1ac0e9..376de379f6 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
@@ -134,7 +134,7 @@ public class ServiceSynchronize extends ServiceBase implements SharedPreferences
             "sync_kept",
             "sync_folders",
             "sync_shared_folders",
-            "ssl_harden", // force reconnect
+            "prefer_ip4", "ssl_harden", // force reconnect
             "badge", "unseen_ignored", // force update badge/widget
             "protocol", "debug", // force reconnect
             "auth_plain",
diff --git a/app/src/main/res/layout/fragment_options_connection.xml b/app/src/main/res/layout/fragment_options_connection.xml
index 9c2bcfe9bd..686fec2359 100644
--- a/app/src/main/res/layout/fragment_options_connection.xml
+++ b/app/src/main/res/layout/fragment_options_connection.xml
@@ -184,6 +184,17 @@
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/tvTimeoutHint" />
 
+        <androidx.appcompat.widget.SwitchCompat
+            android:id="@+id/swPreferIp4"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="12dp"
+            android:text="@string/title_advanced_prefer_ip4"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/etTimeout"
+            app:switchPadding="12dp" />
+
         <androidx.appcompat.widget.SwitchCompat
             android:id="@+id/swSslHarden"
             android:layout_width="0dp"
@@ -193,7 +204,7 @@
             android:text="@string/title_advanced_ssl_harden"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toBottomOf="@id/etTimeout"
+            app:layout_constraintTop_toBottomOf="@id/swPreferIp4"
             app:switchPadding="12dp" />
 
         <eu.faircode.email.FixedTextView
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 4c8ec01c0c..8449f1ec2a 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -328,6 +328,7 @@
     <string name="title_advanced_roaming">Download messages and attachments while roaming</string>
     <string name="title_advanced_rlah">Roam like at home</string>
     <string name="title_advanced_timeout">Connection timeout (seconds)</string>
+    <string name="title_advanced_prefer_ip4">Prefer IPv4 over IPv6</string>
     <string name="title_advanced_ssl_harden">Harden SSL connections</string>
     <string name="title_advanced_manage_connectivity">Manage connectivity</string>