LLCP echo server implementation.

Can be used to test the Android LLCP stack with nfcpy. Disabled
by default.

Also fixed unnecessary JNI release call causing warnings in the
logs.

Change-Id: Iaed159e23dadc1601be2df2aadbe1d9c54c50615

2 files changed, 431 insertions, 0 deletions

diff --git a/src/com/android/nfc/P2pLinkManager.java b/src/com/android/nfc/P2pLinkManager.java
index 466453d..277e739 100755
--- a/src/com/android/nfc/P2pLinkManager.java
+++ b/src/com/android/nfc/P2pLinkManager.java
@@ -16,6 +16,7 @@
 
 package com.android.nfc;
 
+import com.android.nfc.echoserver.EchoServer;
 import com.android.nfc.ndefpush.NdefPushClient;
 import com.android.nfc.ndefpush.NdefPushServer;
 import com.android.nfc.snep.SnepClient;
@@ -97,6 +98,11 @@ public class P2pLinkManager implements Handler.Callback, P2pEventListener.Callba
     static final String TAG = "NfcP2pLinkManager";
     static final boolean DBG = true;
 
+    /** Enables the LLCP EchoServer, which can be used to test the android
+     * LLCP stack against nfcpy.
+     */
+    static final boolean ECHOSERVER_ENABLED = false;
+
     // TODO dynamically assign SAP values
     static final int NDEFPUSH_SAP = 0x10;
 
@@ -105,6 +111,8 @@ public class P2pLinkManager implements Handler.Callback, P2pEventListener.Callba
     static final int MSG_DEBOUNCE_TIMEOUT = 1;
     static final int MSG_RECEIVE_COMPLETE = 2;
     static final int MSG_SEND_COMPLETE = 3;
+    static final int MSG_START_ECHOSERVER = 4;
+    static final int MSG_STOP_ECHOSERVER = 5;
 
     // values for mLinkState
     static final int LINK_STATE_DOWN = 1;
@@ -123,6 +131,7 @@ public class P2pLinkManager implements Handler.Callback, P2pEventListener.Callba
 
     final NdefPushServer mNdefPushServer;
     final SnepServer mDefaultSnepServer;
+    final EchoServer mEchoServer;
     final ActivityManager mActivityManager;
     final PackageManager mPackageManager;
     final Context mContext;
@@ -144,6 +153,11 @@ public class P2pLinkManager implements Handler.Callback, P2pEventListener.Callba
     public P2pLinkManager(Context context) {
         mNdefPushServer = new NdefPushServer(NDEFPUSH_SAP, mNppCallback);
         mDefaultSnepServer = new SnepServer(mDefaultSnepCallback);
+        if (ECHOSERVER_ENABLED) {
+            mEchoServer = new EchoServer();
+        } else {
+            mEchoServer = null;
+        }
         mActivityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
         mPackageManager = context.getPackageManager();
         mContext = context;
@@ -166,9 +180,15 @@ public class P2pLinkManager implements Handler.Callback, P2pEventListener.Callba
             if (!mIsReceiveEnabled && receiveEnable) {
                 mDefaultSnepServer.start();
                 mNdefPushServer.start();
+                if (mEchoServer != null) {
+                    mHandler.sendEmptyMessage(MSG_START_ECHOSERVER);
+                }
             } else if (mIsReceiveEnabled && !receiveEnable) {
                 mDefaultSnepServer.stop();
                 mNdefPushServer.stop();
+                if (mEchoServer != null) {
+                    mHandler.sendEmptyMessage(MSG_STOP_ECHOSERVER);
+                }
             }
             mIsSendEnabled = sendEnable;
             mIsReceiveEnabled = receiveEnable;
@@ -196,6 +216,10 @@ public class P2pLinkManager implements Handler.Callback, P2pEventListener.Callba
         Log.i(TAG, "LLCP activated");
 
         synchronized (P2pLinkManager.this) {
+            if (mEchoServer != null) {
+                mEchoServer.onLlcpActivated();
+            }
+
             switch (mLinkState) {
                 case LINK_STATE_DOWN:
                     mLinkState = LINK_STATE_UP;
@@ -278,6 +302,10 @@ public class P2pLinkManager implements Handler.Callback, P2pEventListener.Callba
     public void onLlcpDeactivated() {
         Log.i(TAG, "LLCP deactivated.");
         synchronized (this) {
+            if (mEchoServer != null) {
+                mEchoServer.onLlcpDeactivated();
+            }
+
             switch (mLinkState) {
                 case LINK_STATE_DOWN:
                 case LINK_STATE_DEBOUNCE:
@@ -410,6 +438,16 @@ public class P2pLinkManager implements Handler.Callback, P2pEventListener.Callba
     @Override
     public boolean handleMessage(Message msg) {
         switch (msg.what) {
+            case MSG_START_ECHOSERVER:
+                synchronized (this) {
+                    mEchoServer.start();
+                    break;
+                }
+            case MSG_STOP_ECHOSERVER:
+                synchronized (this) {
+                    mEchoServer.stop();
+                    break;
+                }
             case MSG_DEBOUNCE_TIMEOUT:
                 synchronized (this) {
                     if (mLinkState != LINK_STATE_DEBOUNCE) {
diff --git a/src/com/android/nfc/echoserver/EchoServer.java b/src/com/android/nfc/echoserver/EchoServer.java
new file mode 100644
index 0000000..bd060f7
--- /dev/null
+++ b/src/com/android/nfc/echoserver/EchoServer.java
@@ -0,0 +1,393 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.nfc.echoserver;
+
+import com.android.nfc.DeviceHost.LlcpConnectionlessSocket;
+import com.android.nfc.LlcpException;
+import com.android.nfc.DeviceHost.LlcpServerSocket;
+import com.android.nfc.DeviceHost.LlcpSocket;
+import com.android.nfc.LlcpPacket;
+import com.android.nfc.NfcService;
+
+import android.os.Handler;
+import android.os.Message;
+import android.util.Log;
+
+import java.io.IOException;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+
+/**
+ * EchoServer is an implementation of the echo server that is used in the
+ * nfcpy LLCP test suite. Enabling the EchoServer allows to test Android
+ * NFC devices against nfcpy.
+ * It has two main features (which run simultaneously):
+ * 1) A connection-based server, which has a receive buffer of two
+ *    packets. Once a packet is received, a 2-second sleep is initiated.
+ *    After these 2 seconds, all packets that are in the receive buffer
+ *    are echoed back on the same connection. The connection-based server
+ *    does not drop packets, but simply blocks if the queue is full.
+ * 2) A connection-less mode, which has a receive buffer of two packets.
+ *    On LLCP link activation, we try to receive data on a pre-determined
+ *    connection-less SAP. Like the connection-based server, all data in
+ *    the buffer is echoed back to the SAP from which the data originated
+ *    after a sleep of two seconds.
+ *    The main difference is that the connection-less SAP is supposed
+ *    to drop packets when the buffer is full.
+ *
+ *    To use with nfcpy:
+ *    - Adapt default_miu (see ECHO_MIU below)
+ *    - llcp-test-client.py --mode=target --co-echo=17 --cl-echo=18 -t 1
+ *
+ *    Modify -t to execute the different tests.
+ *
+ */
+public class EchoServer {
+    static boolean DBG = true;
+
+    static final int DEFAULT_CO_SAP = 0x11;
+    static final int DEFAULT_CL_SAP = 0x12;
+
+    // Link MIU
+    static final int MIU = 128;
+
+    static final String TAG = "EchoServer";
+    static final String CONNECTION_SERVICE_NAME = "urn:nfc:sn:co-echo";
+    static final String CONNECTIONLESS_SERVICE_NAME = "urn:nfc:sn:cl-echo";
+
+    ServerThread mServerThread;
+    ConnectionlessServerThread mConnectionlessServerThread;
+    NfcService mService;
+
+    public interface WriteCallback {
+        public void write(byte[] data);
+    }
+
+    public EchoServer() {
+        mService = NfcService.getInstance();
+    }
+
+    static class EchoMachine implements Handler.Callback {
+        static final int QUEUE_SIZE = 2;
+        static final int ECHO_DELAY_IN_MS = 2000;
+
+        /**
+         * ECHO_MIU must be set equal to default_miu in nfcpy.
+         * The nfcpy echo server is expected to maintain the
+         * packet boundaries and sizes of the requests - that is,
+         * if the nfcpy client sends a service data unit of 48 bytes
+         * in a packet, the echo packet should have a payload of
+         * 48 bytes as well. The "problem" is that the current
+         * Android LLCP implementation simply pushes all received data
+         * in a single large buffer, causing us to loose the packet
+         * boundaries, not knowing how much data to put in a single
+         * response packet. The ECHO_MIU parameter determines exactly that.
+         * We use ECHO_MIU=48 because of a bug in PN544, which does not respect
+         * the target length reduction parameter of the p2p protocol.
+         */
+        static final int ECHO_MIU = 48;
+
+        final BlockingQueue<byte[]> dataQueue;
+        final Handler handler;
+        final boolean dumpWhenFull;
+        final WriteCallback callback;
+
+        // shutdown can be modified from multiple threads, protected by this
+        boolean shutdown = false;
+
+        EchoMachine(WriteCallback callback, boolean dumpWhenFull) {
+            this.callback = callback;
+            this.dumpWhenFull = dumpWhenFull;
+            dataQueue = new LinkedBlockingQueue<byte[]>(QUEUE_SIZE);
+            handler = new Handler(this);
+        }
+
+        public void pushUnit(byte[] unit, int size) {
+            if (dumpWhenFull && dataQueue.remainingCapacity() == 0) {
+                if (DBG) Log.d(TAG, "Dumping data unit");
+            } else {
+                try {
+                    // Split up the packet in ECHO_MIU size packets
+                    int sizeLeft = size;
+
+                    if (dataQueue.isEmpty()) {
+                        // First message: start echo'ing in 2 seconds
+                        handler.sendMessageDelayed(handler.obtainMessage(), ECHO_DELAY_IN_MS);
+                    }
+
+                    if (sizeLeft == 0) {
+                        // Special case: also send a zero-sized data unit
+                        dataQueue.put(new byte[] {});
+                    }
+                    while (sizeLeft > 0) {
+                        int minSize = Math.min(size, ECHO_MIU);
+                        byte[] data = new byte[minSize];
+                        System.arraycopy(unit, 0, data, 0, minSize);
+                        dataQueue.put(data);
+                        sizeLeft -= minSize;
+                    }
+                } catch (InterruptedException e) {
+                    // Ignore
+                }
+            }
+        }
+
+        /** Shuts down the EchoMachine. May block until callbacks
+         *  in progress are completed.
+         */
+        public synchronized void shutdown() {
+            dataQueue.clear();
+            shutdown = true;
+        }
+
+        @Override
+        public synchronized boolean handleMessage(Message msg) {
+            if (shutdown) return true;
+            while (!dataQueue.isEmpty()) {
+                callback.write(dataQueue.remove());
+            }
+            return true;
+        }
+    }
+
+    public class ServerThread extends Thread implements WriteCallback {
+        final EchoMachine echoMachine;
+
+        boolean running = true;
+        LlcpServerSocket serverSocket;
+        LlcpSocket clientSocket;
+
+        public ServerThread() {
+            super();
+            echoMachine = new EchoMachine(this, false);
+        }
+
+        private void handleClient(LlcpSocket socket) {
+            boolean connectionBroken = false;
+            byte[] dataUnit = new byte[1024];
+
+            // Get raw data from remote server
+            while (!connectionBroken) {
+                try {
+                    int size = socket.receive(dataUnit);
+                    if (DBG) Log.d(TAG, "read " + size + " bytes");
+                    if (size < 0) {
+                        connectionBroken = true;
+                        break;
+                    } else {
+                        echoMachine.pushUnit(dataUnit, size);
+                    }
+                } catch (IOException e) {
+                    // Connection broken
+                    connectionBroken = true;
+                    if (DBG) Log.d(TAG, "connection broken by IOException", e);
+                }
+            }
+        }
+
+        @Override
+        public void run() {
+            if (DBG) Log.d(TAG, "about create LLCP service socket");
+            try {
+                serverSocket = mService.createLlcpServerSocket(DEFAULT_CO_SAP,
+                        CONNECTION_SERVICE_NAME, MIU, 1, 1024);
+            } catch (LlcpException e) {
+                return;
+            }
+            if (serverSocket == null) {
+                if (DBG) Log.d(TAG, "failed to create LLCP service socket");
+                return;
+            }
+            if (DBG) Log.d(TAG, "created LLCP service socket");
+
+            while (running) {
+
+                try {
+                    if (DBG) Log.d(TAG, "about to accept");
+                    clientSocket = serverSocket.accept();
+                    if (DBG) Log.d(TAG, "accept returned " + clientSocket);
+                    handleClient(clientSocket);
+                } catch (LlcpException e) {
+                    Log.e(TAG, "llcp error", e);
+                    running = false;
+                } catch (IOException e) {
+                    Log.e(TAG, "IO error", e);
+                    running = false;
+                }
+            }
+
+            echoMachine.shutdown();
+
+            try {
+                clientSocket.close();
+            } catch (IOException e) {
+                // Ignore
+            }
+            clientSocket = null;
+
+            try {
+                serverSocket.close();
+            } catch (IOException e) {
+                // Ignore
+            }
+            serverSocket = null;
+        }
+
+        @Override
+        public void write(byte[] data) {
+            if (clientSocket != null) {
+                try {
+                    clientSocket.send(data);
+                } catch (IOException e) {
+                    // Ignore
+                }
+            }
+        }
+
+        public void shutdown() {
+            running = false;
+            if (serverSocket != null) {
+                try {
+                    serverSocket.close();
+                } catch (IOException e) {
+                    // ignore
+                }
+                serverSocket = null;
+            }
+        }
+    }
+
+    public class ConnectionlessServerThread extends Thread implements WriteCallback {
+        final EchoMachine echoMachine;
+
+        LlcpConnectionlessSocket socket;
+        int mRemoteSap;
+        boolean mRunning = true;
+
+        public ConnectionlessServerThread() {
+            super();
+            echoMachine = new EchoMachine(this, true);
+        }
+
+        @Override
+        public void run() {
+            boolean connectionBroken = false;
+            LlcpPacket packet;
+            if (DBG) Log.d(TAG, "about create LLCP connectionless socket");
+            try {
+                socket = mService.createLlcpConnectionLessSocket(
+                        DEFAULT_CL_SAP);
+                if (socket == null) {
+                    if (DBG) Log.d(TAG, "failed to create LLCP connectionless socket");
+                    return;
+                }
+
+                while (mRunning && !connectionBroken) {
+                    try {
+                        packet = socket.receive();
+                        if (packet == null || packet.getDataBuffer() == null) {
+                            break;
+                        }
+                        byte[] dataUnit = packet.getDataBuffer();
+                        int size = dataUnit.length;
+
+                        if (DBG) Log.d(TAG, "read " + packet.getDataBuffer().length + " bytes");
+                        if (size < 0) {
+                            connectionBroken = true;
+                            break;
+                        } else {
+                            mRemoteSap = packet.getRemoteSap();
+                            echoMachine.pushUnit(dataUnit, size);
+                        }
+                    } catch (IOException e) {
+                        // Connection broken
+                        connectionBroken = true;
+                        if (DBG) Log.d(TAG, "connection broken by IOException", e);
+                    }
+                }
+            } catch (LlcpException e) {
+                Log.e(TAG, "llcp error", e);
+            } finally {
+                echoMachine.shutdown();
+
+                if (socket != null) {
+                    try {
+                        socket.close();
+                    } catch (IOException e) {
+                    }
+                }
+            }
+
+        }
+
+        public void shutdown() {
+            mRunning = false;
+        }
+
+        @Override
+        public void write(byte[] data) {
+            try {
+                socket.send(mRemoteSap, data);
+            } catch (IOException e) {
+                if (DBG) Log.d(TAG, "Error writing data.");
+            }
+        }
+    }
+
+    public void onLlcpActivated() {
+        synchronized (this) {
+            // Connectionless server can only be started once the link is up
+            // - otherwise, all calls to receive() on the connectionless socket
+            // will fail immediately.
+            if (mConnectionlessServerThread == null) {
+                mConnectionlessServerThread = new ConnectionlessServerThread();
+                mConnectionlessServerThread.start();
+            }
+        }
+    }
+
+    public void onLlcpDeactivated() {
+        synchronized (this) {
+            if (mConnectionlessServerThread != null) {
+                mConnectionlessServerThread.shutdown();
+                mConnectionlessServerThread = null;
+            }
+        }
+    }
+
+    /**
+     *  Needs to be called on the UI thread
+     */
+    public void start() {
+        synchronized (this) {
+            if (mServerThread == null) {
+                mServerThread = new ServerThread();
+                mServerThread.start();
+            }
+        }
+
+    }
+
+    public void stop() {
+        synchronized (this) {
+            if (mServerThread != null) {
+                mServerThread.shutdown();
+                mServerThread = null;
+            }
+        }
+    }
+}