1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.nfc.snep;
18
19import com.android.nfc.DeviceHost.LlcpServerSocket;
20import com.android.nfc.DeviceHost.LlcpSocket;
21import com.android.nfc.LlcpException;
22import com.android.nfc.NfcService;
23
24import android.nfc.NdefMessage;
25import android.nfc.NfcAdapter;
26import android.util.Log;
27
28import java.io.IOException;
29
30/**
31 * A simple server that accepts NDEF messages pushed to it over an LLCP connection. Those messages
32 * are typically set on the client side by using {@link NfcAdapter#enableForegroundNdefPush}.
33 */
34public final class SnepServer {
35    private static final String TAG = "SnepServer";
36    private static final boolean DBG = false;
37    private static final int DEFAULT_MIU = 248;
38    private static final int DEFAULT_RW_SIZE = 1;
39
40    public static final int DEFAULT_PORT = 4;
41
42    public static final String DEFAULT_SERVICE_NAME = "urn:nfc:sn:snep";
43
44    final Callback mCallback;
45    final String mServiceName;
46    final int mServiceSap;
47    final int mFragmentLength;
48    final int mMiu;
49    final int mRwSize;
50
51    /** Protected by 'this', null when stopped, non-null when running */
52    ServerThread mServerThread = null;
53    boolean mServerRunning = false;
54
55    public interface Callback {
56        public SnepMessage doPut(NdefMessage msg);
57        public SnepMessage doGet(int acceptableLength, NdefMessage msg);
58    }
59
60    public SnepServer(Callback callback) {
61        mCallback = callback;
62        mServiceName = DEFAULT_SERVICE_NAME;
63        mServiceSap = DEFAULT_PORT;
64        mFragmentLength = -1;
65        mMiu = DEFAULT_MIU;
66        mRwSize = DEFAULT_RW_SIZE;
67    }
68
69    public SnepServer(String serviceName, int serviceSap, Callback callback) {
70        mCallback = callback;
71        mServiceName = serviceName;
72        mServiceSap = serviceSap;
73        mFragmentLength = -1;
74        mMiu = DEFAULT_MIU;
75        mRwSize = DEFAULT_RW_SIZE;
76    }
77
78    public SnepServer(Callback callback, int miu, int rwSize) {
79        mCallback = callback;
80        mServiceName = DEFAULT_SERVICE_NAME;
81        mServiceSap = DEFAULT_PORT;
82        mFragmentLength = -1;
83        mMiu = miu;
84        mRwSize = rwSize;
85    }
86
87    SnepServer(String serviceName, int serviceSap, int fragmentLength, Callback callback) {
88        mCallback = callback;
89        mServiceName = serviceName;
90        mServiceSap = serviceSap;
91        mFragmentLength = fragmentLength;
92        mMiu = DEFAULT_MIU;
93        mRwSize = DEFAULT_RW_SIZE;
94    }
95
96    /** Connection class, used to handle incoming connections */
97    private class ConnectionThread extends Thread {
98        private final LlcpSocket mSock;
99        private final SnepMessenger mMessager;
100
101        ConnectionThread(LlcpSocket socket, int fragmentLength) {
102            super(TAG);
103            mSock = socket;
104            mMessager = new SnepMessenger(false, socket, fragmentLength);
105        }
106
107        @Override
108        public void run() {
109            if (DBG) Log.d(TAG, "starting connection thread");
110            try {
111                boolean running;
112                synchronized (SnepServer.this) {
113                    running = mServerRunning;
114                }
115
116                while (running) {
117                    if (!handleRequest(mMessager, mCallback)) {
118                        break;
119                    }
120
121                    synchronized (SnepServer.this) {
122                        running = mServerRunning;
123                    }
124                }
125            } catch (IOException e) {
126                if (DBG) Log.e(TAG, "Closing from IOException");
127            } finally {
128                try {
129                    if (DBG) Log.d(TAG, "about to close");
130                    mSock.close();
131                } catch (IOException e) {
132                    // ignore
133                }
134            }
135
136            if (DBG) Log.d(TAG, "finished connection thread");
137        }
138    }
139
140    static boolean handleRequest(SnepMessenger messenger, Callback callback) throws IOException {
141        SnepMessage request;
142        try {
143            request = messenger.getMessage();
144        } catch (SnepException e) {
145            if (DBG) Log.w(TAG, "Bad snep message", e);
146            try {
147                messenger.sendMessage(SnepMessage.getMessage(
148                    SnepMessage.RESPONSE_BAD_REQUEST));
149            } catch (IOException e2) {
150                // Ignore
151            }
152            return false;
153        }
154
155        if (((request.getVersion() & 0xF0) >> 4) != SnepMessage.VERSION_MAJOR) {
156            messenger.sendMessage(SnepMessage.getMessage(
157                    SnepMessage.RESPONSE_UNSUPPORTED_VERSION));
158        } else if (request.getField() == SnepMessage.REQUEST_GET) {
159            messenger.sendMessage(callback.doGet(request.getAcceptableLength(),
160                    request.getNdefMessage()));
161        } else if (request.getField() == SnepMessage.REQUEST_PUT) {
162            if (DBG) Log.d(TAG, "putting message " + request.toString());
163            messenger.sendMessage(callback.doPut(request.getNdefMessage()));
164        } else {
165            if (DBG) Log.d(TAG, "Unknown request (" + request.getField() +")");
166            messenger.sendMessage(SnepMessage.getMessage(
167                    SnepMessage.RESPONSE_BAD_REQUEST));
168        }
169        return true;
170    }
171
172    /** Server class, used to listen for incoming connection request */
173    class ServerThread extends Thread {
174        private boolean mThreadRunning = true;
175        LlcpServerSocket mServerSocket;
176
177        @Override
178        public void run() {
179            boolean threadRunning;
180            synchronized (SnepServer.this) {
181                threadRunning = mThreadRunning;
182            }
183
184            while (threadRunning) {
185                if (DBG) Log.d(TAG, "about create LLCP service socket");
186                try {
187                    synchronized (SnepServer.this) {
188                        mServerSocket = NfcService.getInstance().createLlcpServerSocket(mServiceSap,
189                                mServiceName, mMiu, mRwSize, 1024);
190                    }
191                    if (mServerSocket == null) {
192                        if (DBG) Log.d(TAG, "failed to create LLCP service socket");
193                        return;
194                    }
195                    if (DBG) Log.d(TAG, "created LLCP service socket");
196                    synchronized (SnepServer.this) {
197                        threadRunning = mThreadRunning;
198                    }
199
200                    while (threadRunning) {
201                        LlcpServerSocket serverSocket;
202                        synchronized (SnepServer.this) {
203                            serverSocket = mServerSocket;
204                        }
205
206                        if (serverSocket == null) {
207                            if (DBG) Log.d(TAG, "Server socket shut down.");
208                            return;
209                        }
210                        if (DBG) Log.d(TAG, "about to accept");
211                        LlcpSocket communicationSocket = serverSocket.accept();
212                        if (DBG) Log.d(TAG, "accept returned " + communicationSocket);
213                        if (communicationSocket != null) {
214                            int fragmentLength = (mFragmentLength == -1) ?
215                                    mMiu : Math.min(mMiu, mFragmentLength);
216                            new ConnectionThread(communicationSocket, fragmentLength).start();
217                        }
218
219                        synchronized (SnepServer.this) {
220                            threadRunning = mThreadRunning;
221                        }
222                    }
223                    if (DBG) Log.d(TAG, "stop running");
224                } catch (LlcpException e) {
225                    Log.e(TAG, "llcp error", e);
226                } catch (IOException e) {
227                    Log.e(TAG, "IO error", e);
228                } finally {
229                    synchronized (SnepServer.this) {
230                        if (mServerSocket != null) {
231                            if (DBG) Log.d(TAG, "about to close");
232                            try {
233                                mServerSocket.close();
234                            } catch (IOException e) {
235                                // ignore
236                            }
237                            mServerSocket = null;
238                        }
239                    }
240                }
241
242                synchronized (SnepServer.this) {
243                    threadRunning = mThreadRunning;
244                }
245            }
246        }
247
248        public void shutdown() {
249            synchronized (SnepServer.this) {
250                mThreadRunning = false;
251                if (mServerSocket != null) {
252                    try {
253                        mServerSocket.close();
254                    } catch (IOException e) {
255                        // ignore
256                    }
257                    mServerSocket = null;
258                }
259            }
260        }
261    }
262
263    public void start() {
264        synchronized (SnepServer.this) {
265            if (DBG) Log.d(TAG, "start, thread = " + mServerThread);
266            if (mServerThread == null) {
267                if (DBG) Log.d(TAG, "starting new server thread");
268                mServerThread = new ServerThread();
269                mServerThread.start();
270                mServerRunning = true;
271            }
272        }
273    }
274
275    public void stop() {
276        synchronized (SnepServer.this) {
277            if (DBG) Log.d(TAG, "stop, thread = " + mServerThread);
278            if (mServerThread != null) {
279                if (DBG) Log.d(TAG, "shuting down server thread");
280                mServerThread.shutdown();
281                mServerThread = null;
282                mServerRunning = false;
283            }
284        }
285    }
286}
287