ui,tunnel: auto-detect IPv6/IPv4 preference

Detect IP address change.
Request non-VPN network.
Update endpoint when needed.
Unregister network on wgTurnOff and use IPv4 if network is not known.

3 files changed, 33 insertions, 17 deletions

diff --git a/tunnel/src/main/java/com/wireguard/config/Config.java b/tunnel/src/main/java/com/wireguard/config/Config.java
index ee9cebce..12ddb242 100644
--- a/tunnel/src/main/java/com/wireguard/config/Config.java
+++ b/tunnel/src/main/java/com/wireguard/config/Config.java
@@ -9,6 +9,7 @@ import com.wireguard.config.BadConfigException.Location;
 import com.wireguard.config.BadConfigException.Reason;
 import com.wireguard.config.BadConfigException.Section;
 import com.wireguard.util.NonNullForAll;
+import com.wireguard.util.Resolver;
 
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -173,12 +174,19 @@ public final class Config {
      *
      * @return the {@code Config} represented as a series of "key=value" lines
      */
-    public String toWgUserspaceString() {
+    public String toWgUserspaceString(Resolver resolver) {
         final StringBuilder sb = new StringBuilder();
         sb.append(interfaze.toWgUserspaceString());
         sb.append("replace_peers=true\n");
         for (final Peer peer : peers)
-            sb.append(peer.toWgUserspaceString());
+            sb.append(peer.toWgUserspaceString(resolver));
+        return sb.toString();
+    }
+
+    public String toWgEndpointsUserspaceString(Resolver resolver) {
+        final StringBuilder sb = new StringBuilder();
+        for (final Peer peer : peers)
+            sb.append(peer.toWgEndpointsUserspaceString(resolver));
         return sb.toString();
     }
 
diff --git a/tunnel/src/main/java/com/wireguard/config/InetEndpoint.java b/tunnel/src/main/java/com/wireguard/config/InetEndpoint.java
index d1db432b..e1e9d653 100644
--- a/tunnel/src/main/java/com/wireguard/config/InetEndpoint.java
+++ b/tunnel/src/main/java/com/wireguard/config/InetEndpoint.java
@@ -6,6 +6,7 @@
 package com.wireguard.config;
 
 import com.wireguard.util.NonNullForAll;
+import com.wireguard.util.Resolver;
 
 import java.net.Inet4Address;
 import java.net.InetAddress;
@@ -87,24 +88,22 @@ public final class InetEndpoint {
      *
      * @return the resolved endpoint, or {@link Optional#empty()}
      */
-    public Optional<InetEndpoint> getResolved() {
-        if (isResolved)
+    public Optional<InetEndpoint> getResolved(Resolver resolver) {
+        return getResolved(resolver, false);
+    }
+
+    public Optional<InetEndpoint> getResolved(Resolver resolver, Boolean force) {
+        if (!force && isResolved)
             return Optional.of(this);
         synchronized (lock) {
             //TODO(zx2c4): Implement a real timeout mechanism using DNS TTL
-            if (Duration.between(lastResolution, Instant.now()).toMinutes() > 1) {
+            if (force || Duration.between(lastResolution, Instant.now()).toMinutes() > 1) {
                 try {
-                    // Prefer v4 endpoints over v6 to work around DNS64 and IPv6 NAT issues.
-                    final InetAddress[] candidates = InetAddress.getAllByName(host);
-                    InetAddress address = candidates[0];
-                    for (final InetAddress candidate : candidates) {
-                        if (candidate instanceof Inet4Address) {
-                            address = candidate;
-                            break;
-                        }
-                    }
-                    resolved = new InetEndpoint(address.getHostAddress(), true, port);
+                    InetAddress address = resolver.resolve(host);
+                    InetEndpoint resolvedNow = new InetEndpoint(address.getHostAddress(), true, port);
                     lastResolution = Instant.now();
+
+                    resolved = resolvedNow;
                 } catch (final UnknownHostException e) {
                     resolved = null;
                 }
diff --git a/tunnel/src/main/java/com/wireguard/config/Peer.java b/tunnel/src/main/java/com/wireguard/config/Peer.java
index 8a0fd763..1d20a961 100644
--- a/tunnel/src/main/java/com/wireguard/config/Peer.java
+++ b/tunnel/src/main/java/com/wireguard/config/Peer.java
@@ -11,6 +11,7 @@ import com.wireguard.config.BadConfigException.Section;
 import com.wireguard.crypto.Key;
 import com.wireguard.crypto.KeyFormatException;
 import com.wireguard.util.NonNullForAll;
+import com.wireguard.util.Resolver;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -190,18 +191,26 @@ public final class Peer {
      *
      * @return the {@code Peer} represented as a series of "key=value" lines
      */
-    public String toWgUserspaceString() {
+    public String toWgUserspaceString(Resolver resolver) {
         final StringBuilder sb = new StringBuilder();
         // The order here is important: public_key signifies the beginning of a new peer.
         sb.append("public_key=").append(publicKey.toHex()).append('\n');
         for (final InetNetwork allowedIp : allowedIps)
             sb.append("allowed_ip=").append(allowedIp).append('\n');
-        endpoint.flatMap(InetEndpoint::getResolved).ifPresent(ep -> sb.append("endpoint=").append(ep).append('\n'));
+        endpoint.flatMap(ep -> ep.getResolved(resolver)).ifPresent(ep -> sb.append("endpoint=").append(ep).append('\n'));
         persistentKeepalive.ifPresent(pk -> sb.append("persistent_keepalive_interval=").append(pk).append('\n'));
         preSharedKey.ifPresent(psk -> sb.append("preshared_key=").append(psk.toHex()).append('\n'));
         return sb.toString();
     }
 
+    public String toWgEndpointsUserspaceString(Resolver resolver) {
+        final StringBuilder sb = new StringBuilder();
+        // The order here is important: public_key signifies the beginning of a new peer.
+        sb.append("public_key=").append(publicKey.toHex()).append('\n');
+        endpoint.flatMap(ep -> ep.getResolved(resolver, true)).ifPresent(ep -> sb.append("endpoint=").append(ep).append('\n'));
+        return sb.toString();
+    }
+
     @SuppressWarnings("UnusedReturnValue")
     public static final class Builder {
         // See wg(8)