Hesham/wireguard-android
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tunnel: retry DNS resolution for 10 seconds

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This has several problems: 1) it blocks the main thread; 2) it doesn't
distinguish between a permanent error and a transient one; 3) the 10
seconds is hard coded; 4) there's no way for the user to cancel it.

We'll have to improve this.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2021-05-26 18:03:44 +02:00
parent 24ded8070f
commit fe61522f2a
4 changed files with 26 additions and 2 deletions
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3
tunnel/src/main/java/com/wireguard/android/backend/BackendException.java
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@ -55,6 +55,7 @@ public final class BackendException extends Exception {
VPN_NOT_AUTHORIZED,
UNABLE_TO_START_VPN,
TUN_CREATION_ERROR,
GO_ACTIVATION_ERROR_CODE
GO_ACTIVATION_ERROR_CODE,
DNS_RESOLUTION_FAILURE,
}
}

21
tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
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@ -16,6 +16,7 @@ import com.wireguard.android.backend.BackendException.Reason;
import com.wireguard.android.backend.Tunnel.State;
import com.wireguard.android.util.SharedLibraryLoader;
import com.wireguard.config.Config;
import com.wireguard.config.InetEndpoint;
import com.wireguard.config.InetNetwork;
import com.wireguard.config.Peer;
import com.wireguard.crypto.Key;
@ -40,6 +41,7 @@ import androidx.collection.ArraySet;
*/
@NonNullForAll
public final class GoBackend implements Backend {
private static final int DNS_RESOLUTION_RETRIES = 10;
private static final String TAG = "WireGuard/GoBackend";
@Nullable private static AlwaysOnCallback alwaysOnCallback;
private static GhettoCompletableFuture<VpnService> vpnService = new GhettoCompletableFuture<>();
@ -234,6 +236,25 @@ public final class GoBackend implements Backend {
return;
}
dnsRetry: for (int i = 0; i < DNS_RESOLUTION_RETRIES; ++i) {
// Pre-resolve IPs so they're cached when building the userspace string
for (final Peer peer : config.getPeers()) {
final InetEndpoint ep = peer.getEndpoint().orElse(null);
if (ep == null)
continue;
if (ep.getResolved().orElse(null) == null) {
if (i < DNS_RESOLUTION_RETRIES - 1) {
Log.w(TAG, "DNS host \"" + ep.getHost() + "\" failed to resolve; trying again");
Thread.sleep(1000);
continue dnsRetry;
} else
throw new BackendException(Reason.DNS_RESOLUTION_FAILURE, ep.getHost());
}
}
break;
}
// Build config
final String goConfig = config.toWgUserspaceString();

3
ui/src/main/java/com/wireguard/android/util/ErrorMessages.kt
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@ -36,7 +36,8 @@ object ErrorMessages {
BackendException.Reason.VPN_NOT_AUTHORIZED to R.string.vpn_not_authorized_error,
BackendException.Reason.UNABLE_TO_START_VPN to R.string.vpn_start_error,
BackendException.Reason.TUN_CREATION_ERROR to R.string.tun_create_error,
BackendException.Reason.GO_ACTIVATION_ERROR_CODE to R.string.tunnel_on_error
BackendException.Reason.GO_ACTIVATION_ERROR_CODE to R.string.tunnel_on_error,
BackendException.Reason.DNS_RESOLUTION_FAILURE to R.string.tunnel_dns_failure
)
private val KFE_FORMAT_MAP = mapOf(
Key.Format.BASE64 to R.string.key_length_explanation_base64,

1
ui/src/main/res/values/strings.xml
View File

@ -214,6 +214,7 @@
<string name="tunnel_list_placeholder">Add a tunnel using the blue button</string>
<string name="tunnel_name">Tunnel Name</string>
<string name="tunnel_on_error">Unable to turn tunnel on (wgTurnOn returned %d)</string>
<string name="tunnel_dns_failure">Unable to resolve DNS hostname: “%s”</string>
<string name="tunnel_rename_error">Unable to rename tunnel: %s</string>
<string name="tunnel_rename_success">Successfully renamed tunnel to “%s”</string>
<string name="type_name_go_userspace">Go userspace</string>