Fix UDPInput thread death, TCPOutput double-free, and compile warnings

app/src/main/java/xyz/hexene/localvpn/LRUCache.java

@@ -18,15 +18,12 @@
 
 import java.util.LinkedHashMap;
 
-public class LRUCache<K, V> extends LinkedHashMap<K, V>
-{
+public class LRUCache<K, V> extends LinkedHashMap<K, V> {
     private int maxSize;
-    private CleanupCallback callback;
+    private CleanupCallback<K, V> callback;
 
-    public LRUCache(int maxSize, CleanupCallback callback)
-    {
+    public LRUCache(int maxSize, CleanupCallback<K, V> callback) {
         super(maxSize + 1, 1, true);
-
         this.maxSize = maxSize;
         this.callback = callback;
     }

app/src/main/java/xyz/hexene/localvpn/Packet.java

@@ -236,7 +236,7 @@ private enum TransportProtocol
             UDP(17),
             Other(0xFF);
 
-            private int protocolNumber;
+            private final int protocolNumber;
 
             TransportProtocol(int protocolNumber)
             {

app/src/main/java/xyz/hexene/localvpn/TCPOutput.java

@@ -35,15 +35,17 @@ public class TCPOutput implements Runnable
 {
     private static final String TAG = TCPOutput.class.getSimpleName();
 
-    private LocalVPNService vpnService;
+    private android.net.VpnService vpnService;
     private ConcurrentLinkedQueue<Packet> inputQueue;
     private ConcurrentLinkedQueue<ByteBuffer> outputQueue;
     private Selector selector;
 
     private Random random = new Random();
-    public TCPOutput(ConcurrentLinkedQueue<Packet> inputQueue, ConcurrentLinkedQueue<ByteBuffer> outputQueue,
-                     Selector selector, LocalVPNService vpnService)
-    {
+    public TCPOutput(
+        ConcurrentLinkedQueue<Packet> inputQueue,
+        ConcurrentLinkedQueue<ByteBuffer> outputQueue,
+        Selector selector,
+        android.net.VpnService vpnService) {
         this.inputQueue = inputQueue;
         this.outputQueue = outputQueue;
         this.selector = selector;
@@ -266,7 +268,7 @@ private void sendRST(TCB tcb, int prevPayloadSize, ByteBuffer buffer)
 
     private void closeCleanly(TCB tcb, ByteBuffer buffer)
     {
-        ByteBufferPool.release(buffer);
+        // ByteBufferPool.release(buffer); // Commented out to prevent double-free corruption
         TCB.closeTCB(tcb);
     }
 }

app/src/main/java/xyz/hexene/localvpn/UDPInput.java

@@ -71,9 +71,15 @@ public void run()
                         receiveBuffer.position(HEADER_SIZE);
 
                         DatagramChannel inputChannel = (DatagramChannel) key.channel();
-                        // XXX: We should handle any IOExceptions here immediately,
-                        // but that probably won't happen with UDP
-                        int readBytes = inputChannel.read(receiveBuffer);
+                        int readBytes;
+                        try {
+                            readBytes = inputChannel.read(receiveBuffer);
+                        } catch (IOException e) {
+                            Log.e(TAG, "UDP read error", e);
+                            key.cancel();
+                            ByteBufferPool.release(receiveBuffer);
+                            continue; // Prevent thread death, skip to next packet
+                        }
 
                         Packet referencePacket = (Packet) key.attachment();
                         referencePacket.updateUDPBuffer(receiveBuffer, readBytes);

app/src/main/java/xyz/hexene/localvpn/UDPOutput.java

@@ -33,7 +33,7 @@ public class UDPOutput implements Runnable
 {
     private static final String TAG = UDPOutput.class.getSimpleName();
 
-    private LocalVPNService vpnService;
+    private android.net.VpnService vpnService;
     private ConcurrentLinkedQueue<Packet> inputQueue;
     private Selector selector;
 
@@ -48,8 +48,7 @@ public void cleanup(Map.Entry<String, DatagramChannel> eldest)
                 }
             });
 
-    public UDPOutput(ConcurrentLinkedQueue<Packet> inputQueue, Selector selector, LocalVPNService vpnService)
-    {
+    public UDPOutput(ConcurrentLinkedQueue<Packet> inputQueue, Selector selector, android.net.VpnService vpnService) {
         this.inputQueue = inputQueue;
         this.selector = selector;
         this.vpnService = vpnService;