Read PCAPdroid extensions metadata from Pcapng

A PCAP/Pcapng reader has been implemented to support parsing the
PCAPdroid extensions metadata. This allows displaying a number of
information in the UI when loading from a Pcapng file, in particular:

- when the dump was generated with root, show the capture interface
  name
- show the UID (app) related to a given connection
- if the dump contains UIDs of uninstalled apps, show the
  original package name and app name

Closes #479

.gitignore

@@ -13,6 +13,7 @@ local.properties
 .DS_Store
 build/
 captures/
+pcap/
 .externalNativeBuild
 .cxx
 app/release/

app/src/main/java/com/emanuelef/remote_capture/AppsResolver.java

@@ -24,6 +24,7 @@
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
 import android.graphics.drawable.Drawable;
+import android.util.ArrayMap;
 import android.util.SparseArray;
 
 import com.emanuelef.remote_capture.interfaces.DrawableLoader;
@@ -37,6 +38,8 @@
 
 public class AppsResolver {
     private static final String TAG = "AppsResolver";
+    private static final SparseArray<AppDescriptor> mMappedUids = new SparseArray<>();
+    private static final ArrayMap<String, AppDescriptor> mMappedPackages = new ArrayMap<>();
     private final SparseArray<AppDescriptor> mApps;
     private final PackageManager mPm;
     private final Context mContext;
@@ -90,10 +93,35 @@ private void initVirtualApps() {
                 virtualIconLoader,"nobody", 9999, true));
     }
 
+    public synchronized static void clearMappedApps() {
+        mMappedUids.clear();
+        mMappedPackages.clear();
+    }
+
+    // Map the uid to the given package_name and app_name
+    // This is need for apps which are not installed in this device
+    public synchronized static void addMappedApp(int uid, String packageName, String appName) {
+        AppDescriptor dsc = new AppDescriptor(appName, null, packageName, uid, false);
+        mMappedUids.put(uid, dsc);
+        mMappedPackages.put(packageName, dsc);
+    }
+
+    private synchronized static AppDescriptor getMappedApp(int uid) {
+        return mMappedUids.get(uid);
+    }
+
+    private synchronized static AppDescriptor getMappedApp(String packageName) {
+        return mMappedPackages.get(packageName);
+    }
+
     // Get the AppDescriptor corresponding to the given package name
     // No caching occurs. Virtual apps cannot be used.
     // This is public to provide a fast resolution alternative to getAppByPackage
     public static AppDescriptor resolveInstalledApp(PackageManager pm, String packageName, int pm_flags, boolean warn_not_found) {
+        AppDescriptor dsc = getMappedApp(packageName);
+        if (dsc != null)
+            return dsc;
+
         PackageInfo pinfo;
 
         try {
@@ -113,6 +141,10 @@ public static AppDescriptor resolveInstalledApp(PackageManager pm, String packag
 
     @SuppressLint("DiscouragedPrivateApi")
     public @Nullable AppDescriptor getAppByUid(int uid, int pm_flags) {
+        AppDescriptor dsc = getMappedApp(uid);
+        if (dsc != null)
+            return dsc;
+
         AppDescriptor app = mApps.get(uid);
         if(app != null)
             return app;
@@ -180,6 +212,10 @@ public static AppDescriptor resolveInstalledApp(PackageManager pm, String packag
     /* Lookup a UID by package name (including virtual apps).
      * UID_NO_FILTER is returned if no match is found. */
     public int getUid(String package_name) {
+        AppDescriptor dsc = getMappedApp(package_name);
+        if (dsc != null)
+            return dsc.getUid();
+
         if(!package_name.contains(".")) {
             // This is a virtual app
             for(int i=0; i<mApps.size(); i++) {

app/src/main/java/com/emanuelef/remote_capture/CaptureService.java

@@ -201,6 +201,7 @@ protected void attachBaseContext(Context base) {
     @Override
     public void onCreate() {
         Log.d(CaptureService.TAG, "onCreate");
+        AppsResolver.clearMappedApps();
         nativeAppsResolver = new AppsResolver(this);
         mPrefs = PreferenceManager.getDefaultSharedPreferences(this);
         mSettings = new CaptureSettings(this, mPrefs); // initialize to prevent NULL pointer exceptions in methods (e.g. isRootCapture)
@@ -1484,6 +1485,18 @@ public String getPackageNameByUid(int uid) {
         return dsc.getPackageName();
     }
 
+    public void loadUidMapping(int uid, String package_name, String app_name) {
+        if (uid < 0)
+            return;
+
+        AppDescriptor dsc = nativeAppsResolver.getAppByUid(uid, 0);
+
+        if ((dsc == null) || !dsc.getPackageName().equals(package_name)) {
+            // This uid corresponds to a different app than the one on the Pcapng
+            AppsResolver.addMappedApp(uid, package_name, app_name);
+        }
+    }
+
     /* Exports a PCAP data chunk */
     public void dumpPcapData(byte[] data) {
         if((mDumper != null) && (data.length > 0)) {
@@ -1513,7 +1526,10 @@ public void reportError(String msg) {
 
             // Try to get a translated string (see errors.h)
             switch (msg) {
-                case "Invalid PCAP file":
+                case "Unsupported PCAP/Pcapng file":
+                    err = getString(R.string.unsupported_pcap_file);
+                    break;
+                case "Invalid PCAP/Pcapng file":
                     err = getString(R.string.invalid_pcap_file);
                     break;
                 case "Could not open the capture interface":
@@ -1522,7 +1538,7 @@ public void reportError(String msg) {
                 case "Unsupported datalink":
                     err = getString(R.string.unsupported_pcap_datalink);
                     break;
-                case "The specified PCAP file does not exist":
+                case "The specified PCAP/Pcapng file does not exist":
                     err = getString(R.string.pcap_file_not_exists);
                     break;
                 case "pcapd daemon start failure":
@@ -1533,7 +1549,7 @@ public void reportError(String msg) {
                     if(mSettings.root_capture)
                         err = getString(R.string.root_capture_start_failed);
                     break;
-                case "PCAP read error":
+                case "PCAP/Pcapng read error":
                     err = getString(R.string.pcap_read_error);
                     break;
             }

app/src/main/java/com/emanuelef/remote_capture/adapters/AppsStatsAdapter.java

@@ -125,7 +125,7 @@ public AppsStatsAdapter(Context context) {
         mContext = context;
         mApps = new AppsResolver(context);
         mLayoutInflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
-        mUnknownIcon = ContextCompat.getDrawable(mContext, android.R.drawable.ic_menu_help);
+        mUnknownIcon = ContextCompat.getDrawable(mContext, R.drawable.ic_image);
         mPrefs = PreferenceManager.getDefaultSharedPreferences(mContext);
         mBlocklist = PCAPdroid.getInstance().getBlocklist();
         mWhitelist = PCAPdroid.getInstance().getFirewallWhitelist();

app/src/main/java/com/emanuelef/remote_capture/fragments/AppOverview.java

@@ -23,6 +23,7 @@
 import android.content.Intent;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
+import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.Handler;
@@ -41,6 +42,7 @@
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
 import androidx.core.graphics.Insets;
 import androidx.core.view.MenuProvider;
 import androidx.core.view.ViewCompat;
@@ -116,7 +118,10 @@ public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceStat
 
         ((TextView)view.findViewById(R.id.uid)).setText(Utils.formatInteger(ctx, dsc.getUid()));
         ((TextView)view.findViewById(R.id.name)).setText(dsc.getName());
-        ((ImageView)view.findViewById(R.id.app_icon)).setImageDrawable(dsc.getIcon());
+        Drawable icon = dsc.getIcon();
+        if (icon == null)
+            icon = ContextCompat.getDrawable(ctx, R.drawable.ic_image);
+        ((ImageView)view.findViewById(R.id.app_icon)).setImageDrawable(icon);
 
         mPinfo = dsc.getPackageInfo();
 

app/src/main/jni/core/CMakeLists.txt

@@ -3,12 +3,13 @@ project(core)
 add_library(capture SHARED
         pcapdroid.c
         capture_vpn.c
-        capture_libpcap.c
+        capture_pcap.c
         ip_lru.c
         ndpi_config.c
         crc32.c
         blacklist.c
         pcap_dump.c
+        pcap_reader.c
         log_writer.c
         port_map.c
         jni_impl.c)