Added debug setting

app/src/main/java/eu/faircode/netguard/ActivitySettings.java

@@ -249,8 +249,14 @@ public class ActivitySettings extends AppCompatActivity implements SharedPrefere
             options.removePreference(screen.findPreference("national_roaming"));
         }
 
-        if (!(Util.isDebuggable(this) || Util.getSelfVersionName(this).contains("beta")))
+        if (!(Util.isDebuggable(this) || Util.getSelfVersionName(this).contains("beta"))) {
             screen.removePreference(screen.findPreference("category_development"));
+            SharedPreferences.Editor edit = prefs.edit();
+            edit.remove("debug");
+            edit.remove("loglevel");
+            edit.remove("dns");
+            edit.apply();
+        }
     }
 
     @Override
@@ -453,7 +459,7 @@ public class ActivitySettings extends AppCompatActivity implements SharedPrefere
         } else if ("stats_samples".equals(name)) {
             getPreferenceScreen().findPreference(name).setTitle(getString(R.string.setting_stats_samples, prefs.getString(name, "90")));
 
-        } else if ("loglevel".equals(name))
+        } else if ("debug".equals(name) || "loglevel".equals(name))
             SinkholeService.reload(null, "changed " + name, this);
 
         else if ("dns".equals(name)) {

app/src/main/java/eu/faircode/netguard/SinkholeService.java

@@ -120,7 +120,7 @@ public class SinkholeService extends VpnService implements SharedPreferences.OnS
 
     private native void jni_init();
 
-    private native void jni_start(int tun, int[] uids, String hosts, boolean log, boolean filter, int loglevel);
+    private native void jni_start(int tun, int[] uids, String hosts, boolean log, boolean filter, boolean debug, int loglevel);
 
     private native void jni_stop(int tun, boolean clear);
 
@@ -666,6 +666,8 @@ public class SinkholeService extends VpnService implements SharedPreferences.OnS
         String vpnDns = prefs.getString("dns", sysDns);
         Log.i(TAG, "DNS system=" + sysDns + " VPN=" + vpnDns);
         try {
+            if (TextUtils.isEmpty(vpnDns.trim()))
+                throw new IllegalArgumentException();
             InetAddress.getByName(vpnDns);
             Log.i(TAG, "DNS using=" + vpnDns);
             return vpnDns;
@@ -756,10 +758,13 @@ public class SinkholeService extends VpnService implements SharedPreferences.OnS
         boolean filter = prefs.getBoolean("filter", false);
         boolean use_hosts = prefs.getBoolean("use_hosts", false);
         if (log || filter) {
+            boolean debug = prefs.getBoolean("debug", false);
             int prio = Integer.parseInt(prefs.getString("loglevel", Integer.toString(Log.INFO)));
+            if (!debug)
+                prio = Log.WARN;
             File hosts = new File(getFilesDir(), "hosts.txt");
             String hname = (use_hosts && hosts.exists() ? hosts.getAbsolutePath() : null);
-            jni_start(vpn.getFd(), getAllowedUids(listAllowed), hname, log, filter, prio);
+            jni_start(vpn.getFd(), getAllowedUids(listAllowed), hname, log, filter, debug, prio);
         }
     }
 

app/src/main/jni/netguard/netguard.c

@@ -56,6 +56,7 @@ jboolean signaled = 0;
 struct udp_session *udp_session = NULL;
 struct tcp_session *tcp_session = NULL;
 
+int debug = 0;
 int loglevel = 0;
 FILE *pcap_file = NULL;
 
@@ -106,11 +107,13 @@ Java_eu_faircode_netguard_SinkholeService_jni_1start(
         jint tun, jintArray uids_,
         jstring hosts_,
         jboolean log, jboolean filter,
-        jint loglevel_) {
+        jboolean debug_, jint loglevel_) {
 
+    debug = debug_;
     loglevel = loglevel_;
-    log_android(ANDROID_LOG_WARN, "Starting tun=%d log %d filter %d level %d",
-                tun, log, filter, loglevel_);
+
+    log_android(ANDROID_LOG_WARN, "Starting tun=%d log %d filter %d debug %d level %d",
+                tun, log, filter, debug, loglevel);
 
     // Set blocking
     int flags = fcntl(tun, F_GETFL, 0);
@@ -1050,23 +1053,23 @@ void handle_ip(const struct arguments *args, const uint8_t *buffer, const size_t
     // Handle allowed traffic
     int log = 0;
     if (allowed) {
-        if (protocol == IPPROTO_UDP)
+        if (protocol == IPPROTO_UDP) {
             allowed = handle_udp(args, buffer, length, uid);
-        else if (protocol == IPPROTO_TCP) {
+            log = (debug || dport != 53);
+        } else if (protocol == IPPROTO_TCP) {
             allowed = handle_tcp(args, buffer, length, uid);
-            if (!allowed && loglevel < ANDROID_LOG_WARN)
+            log = (debug || syn);
+        }
+        else {
+            allowed = 0;
             log = 1;
         }
-        else
-            allowed = 0;
     }
 
     // Log traffic
-    if (args->log) {
-        if (!args->filter || syn || log || protocol != IPPROTO_TCP)
+    if (args->log && (!args->filter || log))
         log_packet(args, version, protocol, flags, source, sport, dest, dport, uid, allowed);
 }
-}
 
 jboolean handle_udp(const struct arguments *args, const uint8_t *buffer, size_t length, int uid) {
     // Check version
@@ -1802,7 +1805,6 @@ int write_fin_ack(const struct arguments *args, struct tcp_session *cur, size_t
 }
 
 void write_rst(const struct arguments *args, struct tcp_session *cur) {
-    log_android(ANDROID_LOG_WARN, "Sending RST");
     if (write_tcp(args, cur, NULL, 0, 0, 0, 0, 0, 1) < 0)
         log_android(ANDROID_LOG_ERROR, "write RST error %d: %s", errno, strerror((errno)));
     cur->state = TCP_TIME_WAIT;
@@ -1918,7 +1920,7 @@ ssize_t write_udp(const struct arguments *args, const struct udp_session *cur,
 #endif
 
     if (res >= 0) {
-        if (args->log)
+        if (args->log && (debug || ntohs(cur->dest) != 53))
             log_packet(args, cur->version, IPPROTO_UDP, "",
                        source, ntohs(udp->source), dest, ntohs(udp->dest), cur->uid, 1);
 

app/src/main/res/xml/preferences.xml

@@ -147,8 +147,13 @@
     <PreferenceCategory
         android:key="category_development"
         android:title="Development">
+        <SwitchPreference
+            android:defaultValue="false"
+            android:key="debug"
+            android:title="Debug" />
         <ListPreference
             android:defaultValue="4"
+            android:dependency="debug"
             android:entries="@array/logLevelNames"
             android:entryValues="@array/logLevelValues"
             android:key="loglevel"