Native poll

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

@@ -85,6 +85,7 @@ public class SinkholeService extends VpnService implements SharedPreferences.OnS
     private Object subscriptionsChangedListener = null;
     private ParcelFileDescriptor vpn = null;
     private Thread receiveThread = null;
+    private Thread pollThread = null;
 
     private volatile Looper mServiceLooper;
     private volatile ServiceHandler mServiceHandler;
@@ -120,7 +121,7 @@ public class SinkholeService extends VpnService implements SharedPreferences.OnS
 
     private native void jni_decode(byte[] buffer, int length);
 
-    private native void jni_receive(int fd);
+    private native void jni_poll();
 
     static {
         System.loadLibrary("netguard");
@@ -728,8 +729,22 @@ public class SinkholeService extends VpnService implements SharedPreferences.OnS
                     }
                 }
             }
-        }, getString(R.string.app_name) + " debug");
+        }, getString(R.string.app_name) + " receive");
         receiveThread.start();
+
+        pollThread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                while (!Thread.currentThread().isInterrupted())
+                    try {
+                        Thread.sleep(5000);
+                        jni_poll();
+                    } catch (InterruptedException ignore) {
+                        break;
+                    }
+            }
+        }, getString(R.string.app_name) + " poll");
+        pollThread.start();
     }
 
     // Called from native code
@@ -748,6 +763,8 @@ public class SinkholeService extends VpnService implements SharedPreferences.OnS
     private void stopReceiving() {
         if (receiveThread != null)
             receiveThread.interrupt();
+        if (pollThread != null)
+            pollThread.interrupt();
     }
 
     private BroadcastReceiver interactiveStateReceiver = new BroadcastReceiver() {

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

@@ -8,6 +8,7 @@
 #include <netinet/ip6.h>
 #include <netinet/udp.h>
 #include <netinet/tcp.h>
+#include <pthread.h>
 
 // This should go into a header file later
 
@@ -47,12 +48,18 @@ char *hex(jbyte *, int);
 
 int tun;
 struct connection *connection = NULL;
+pthread_mutex_t poll_lock;
 
 // JNI interface
 
 JNIEXPORT void JNICALL
 Java_eu_faircode_netguard_SinkholeService_jni_1init(JNIEnv *env, jobject instance) {
     __android_log_print(ANDROID_LOG_INFO, TAG, "Init");
+
+    if (pthread_mutex_init(&poll_lock, NULL) != 0)
+        __android_log_print(ANDROID_LOG_ERROR, TAG, "Mutex init error %d: %s",
+                            errno, strerror(errno));
+    // TODO pthread_mutex_destroy
 }
 
 JNIEXPORT void JNICALL
@@ -70,26 +77,17 @@ Java_eu_faircode_netguard_SinkholeService_jni_1decode(JNIEnv *env, jobject insta
 }
 
 JNIEXPORT void JNICALL
-Java_eu_faircode_netguard_SinkholeService_jni_1receive(JNIEnv *env, jobject instance, jint fd) {
+Java_eu_faircode_netguard_SinkholeService_jni_1poll(JNIEnv *env, jobject instance) {
-    int len;
+    __android_log_print(ANDROID_LOG_DEBUG, TAG, "Poll");
-    jbyte buffer[MAXPKT];
+    poll();
-    while (1) {
-        len = read(fd, buffer, sizeof(buffer));
-        if (len < 0) {
-            __android_log_print(ANDROID_LOG_WARN, TAG, "Receive error=%d", len);
-            return;
-
-        } else if (len > 0)
-            decode(env, instance, buffer, len);
-
-        else
-            __android_log_print(ANDROID_LOG_WARN, TAG, "Nothing received");
-    }
 }
-
 // Private functions
 
 void poll() {
+    if (pthread_mutex_lock(&poll_lock) != 0)
+        __android_log_print(ANDROID_LOG_ERROR, TAG, "Mutex lock error %d: %s",
+                            errno, strerror(errno));
+
     time_t now = time(NULL);
 
     struct connection *last = NULL;
@@ -207,9 +205,8 @@ void poll() {
 
                     // Send packet
                     __android_log_print(ANDROID_LOG_DEBUG, TAG,
-                                        "Sending SYN+ACK to tun %s/%u ack %u len %d %s",
+                                        "Sending SYN+ACK to tun %s/%u ack %u",
-                                        to, ntohs(tcp->dest), ntohl(tcp->ack_seq), len,
+                                        to, ntohs(tcp->dest), ntohl(tcp->ack_seq));
-                                        hex(buffer, len));
                     if (write(tun, buffer, len) < 0) {
                         // TODO
                         __android_log_print(ANDROID_LOG_ERROR, TAG, "write error %d: %s",
@@ -228,6 +225,10 @@ void poll() {
 
         cur = cur->next;
     }
+
+    if (pthread_mutex_unlock(&poll_lock) != 0)
+        __android_log_print(ANDROID_LOG_ERROR, TAG, "Mutex unlock error %d: %s",
+                            errno, strerror(errno));
 }
 
 void handle_tcp(JNIEnv *env, jobject instance, jbyte *buffer, int len) {
@@ -237,7 +238,7 @@ void handle_tcp(JNIEnv *env, jobject instance, jbyte *buffer, int len) {
         return;
 
     // Copy buffer
-    jbyte *copy = malloc(len); // TODO free
+    jbyte *copy = malloc(len); // TODO check/free
     memcpy(copy, buffer, len);
 
     // Get headers
@@ -263,7 +264,7 @@ void handle_tcp(JNIEnv *env, jobject instance, jbyte *buffer, int len) {
                                 ntohs(tcphdr->dest), ntohl(tcphdr->seq));
 
             // Register connection
-            struct connection *syn = malloc(sizeof(struct connection));
+            struct connection *syn = malloc(sizeof(struct connection)); // TODO check/free
             syn->time = time(NULL);
             syn->remote_seq = ntohl(tcphdr->seq);
             syn->local_seq = 123;  // TODO randomize