Recover Android VPN probes after first stall

clients/android/app/build.gradle

@@ -30,8 +30,8 @@ android {
         applicationId "su.cin.rapvpn"
         minSdk 26
         targetSdk 35
-        versionCode 185
+        versionCode 186
-        versionName "0.2.185"
+        versionName "0.2.186"
         buildConfigField "String", "DEFAULT_BACKEND_URL", "\"${normalizeGradleString(defaultBackendUrl)}\""
         buildConfigField "String", "DEFAULT_CLUSTER_ID", "\"${normalizeGradleString(defaultClusterId)}\""
         buildConfigField "String", "DEFAULT_ORGANIZATION_ID", "\"${normalizeGradleString(defaultOrganizationId)}\""

clients/android/app/src/main/java/su/cin/rapvpn/RapDiagnosticService.java

@@ -69,6 +69,10 @@ public class RapDiagnosticService extends Service {
     private static final long COMMAND_STALE_MS = 45000;
     private static final long COMMAND_ORPHAN_MS = 60000;
     private static final long POLL_FORCE_MS = 45000;
+    private static final int RECOVERY_TCP_TIMEOUT_MS = 8000;
+    private static final int RECOVERY_PAGE_TIMEOUT_MS = 25000;
+    private static final int RECOVERY_DOWNLOAD_CONNECT_TIMEOUT_MS = 8000;
+    private static final int RECOVERY_DOWNLOAD_READ_TIMEOUT_MS = 12000;
     private volatile boolean running;
     private Thread worker;
     private Thread supervisor;
@@ -478,14 +482,14 @@ public class RapDiagnosticService extends Service {
         }
         if (isRecoverableVPNProbe(type) && looksLikeVPNStall(result)) {
             String firstResult = result;
-            Thread.sleep(1500);
+            String recovery = controlledRestartVPNRuntime(client, clusterId);
-            String fastRetry = runVPNProbeCommand(type, params);
+            Thread.sleep(2500);
-            if (!looksLikeVPNStall(fastRetry)) {
+            String recoveryRetry = runVPNProbeCommand(type, recoveryProbePayload(type, params), true);
-                result = firstResult + " | fast_retry=" + fastRetry;
+            if (!looksLikeVPNStall(recoveryRetry)) {
+                result = firstResult + " | recovery=" + recovery + " | recovery_retry=" + recoveryRetry;
             } else {
-                String recovery = controlledRestartVPNRuntime(client, clusterId);
+                Thread.sleep(1500);
-                Thread.sleep(4000);
+                result = firstResult + " | recovery=" + recovery + " | recovery_retry=" + recoveryRetry + " | final_retry=" + runVPNProbeCommand(type, recoveryProbePayload(type, params), true);
-                result = firstResult + " | fast_retry=" + fastRetry + " | recovery=" + recovery + " | retry=" + runVPNProbeCommand(type, params);
             }
         }
         lastCommandType = type;
@@ -661,6 +665,10 @@ public class RapDiagnosticService extends Service {
     }
 
     private String runVPNProbeCommand(String type, JSONObject payload) {
+        return runVPNProbeCommand(type, payload, false);
+    }
+
+    private String runVPNProbeCommand(String type, JSONObject payload, boolean recoveryAttempt) {
         if ("vpn_http_get".equals(type)) {
             return runVPNHttpGet(payload.optString("url", "http://192.168.200.61:18080/"));
         }
@@ -671,11 +679,37 @@ public class RapDiagnosticService extends Service {
             return runVPNTCPConnect(payload.optString("host", "192.168.200.95"), payload.optInt("port", 3389), payload.optInt("timeout_ms", 7000));
         }
         if ("vpn_download_test".equals(type)) {
+            if (recoveryAttempt) {
+                return runVPNDownloadTest(
+                        payload.optString("url", "http://192.168.200.61:18080/downloads/rap-android-rdp-vpn-build.json"),
+                        RECOVERY_DOWNLOAD_CONNECT_TIMEOUT_MS,
+                        RECOVERY_DOWNLOAD_READ_TIMEOUT_MS);
+            }
             return runVPNDownloadTest(payload.optString("url", "http://192.168.200.61:18080/downloads/rap-android-rdp-vpn-build.json"));
         }
         return "retry skipped: unsupported probe " + type;
     }
 
+    private JSONObject recoveryProbePayload(String type, JSONObject payload) {
+        JSONObject copy;
+        try {
+            copy = payload == null ? new JSONObject() : new JSONObject(payload.toString());
+        } catch (Exception e) {
+            copy = new JSONObject();
+        }
+        try {
+            if ("vpn_tcp_connect".equals(type) || "vpn_rdp_probe".equals(type)) {
+                int requested = copy.optInt("timeout_ms", RECOVERY_TCP_TIMEOUT_MS);
+                copy.put("timeout_ms", Math.max(1000, Math.min(requested, RECOVERY_TCP_TIMEOUT_MS)));
+            } else if ("vpn_page_probe".equals(type)) {
+                int requested = copy.optInt("timeout_ms", RECOVERY_PAGE_TIMEOUT_MS);
+                copy.put("timeout_ms", Math.max(10000, Math.min(requested, RECOVERY_PAGE_TIMEOUT_MS)));
+            }
+        } catch (Exception ignored) {
+        }
+        return copy;
+    }
+
     private String controlledRestartVPNRuntime(RapApiClient client, String clusterId) {
         SharedPreferences prefs = getSharedPreferences(PREFS, MODE_PRIVATE);
         String connectionId = prefs.getString(PREF_VPN_CONNECTION_ID, "");
@@ -1051,6 +1085,10 @@ public class RapDiagnosticService extends Service {
     }
 
     private String runVPNDownloadTest(String target) {
+        return runVPNDownloadTest(target, 15000, 20000);
+    }
+
+    private String runVPNDownloadTest(String target, int connectTimeoutMs, int readTimeoutMs) {
         try {
             Network vpn = waitForVPNNetwork(5000);
             if (vpn == null) {
@@ -1058,8 +1096,8 @@ public class RapDiagnosticService extends Service {
             }
             URL url = new URL(target);
             HttpURLConnection connection = (HttpURLConnection) vpn.openConnection(url);
-            connection.setConnectTimeout(15000);
+            connection.setConnectTimeout(Math.max(1000, connectTimeoutMs));
-            connection.setReadTimeout(20000);
+            connection.setReadTimeout(Math.max(1000, readTimeoutMs));
             connection.setInstanceFollowRedirects(false);
             int code = connection.getResponseCode();
             int bytes = 0;