MifareUltralight.java revision 20e62c9f1466ace5771e244f03a995dc0939b11b 
1/*
2 * Copyright (C) 2010 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 android.nfc.tech;
18
19import android.nfc.ErrorCodes;
20import android.nfc.Tag;
21import android.nfc.TagLostException;
22import android.os.Bundle;
23import android.os.RemoteException;
24import android.util.Log;
25
26import java.io.IOException;
27
28//TOOD: Ultralight C 3-DES authentication, one-way counter
29
30/**
31 * Provides access to MIFARE Ultralight properties and I/O operations on a {@link Tag}.
32 *
33 * <p>Acquire a {@link MifareUltralight} object using {@link #get}.
34 *
35 * <p>MIFARE Ultralight compatible tags have 4 byte pages {@link #PAGE_SIZE}.
36 * The primary operations on an Ultralight tag are {@link #readPages} and
37 * {@link #writePage}.
38 *
39 * <p>The original MIFARE Ultralight consists of a 64 byte EEPROM. The first
40 * 4 pages are for the OTP area, manufacturer data, and locking bits. They are
41 * readable and some bits are writable. The final 12 pages are the user
42 * read/write area. For more information see the NXP data sheet MF0ICU1.
43 *
44 * <p>The MIFARE Ultralight C consists of a 192 byte EEPROM. The first 4 pages
45 * are for OTP, manufacturer data, and locking bits. The next 36 pages are the
46 * user read/write area. The next 4 pages are additional locking bits, counters
47 * and authentication configuration and are readable. The final 4 pages are for
48 * the authentication key and are not readable. For more information see the
49 * NXP data sheet MF0ICU2.
50 *
51 * <p>Implementation of this class on a Android NFC device is optional.
52 * If it is not implemented, then
53 * {@link MifareUltralight} will never be enumerated in {@link Tag#getTechList}.
54 * If it is enumerated, then all {@link MifareUltralight} I/O operations will be supported.
55 * In either case, {@link NfcA} will also be enumerated on the tag,
56 * because all MIFARE Ultralight tags are also {@link NfcA} tags.
57 *
58 * <p class="note"><strong>Note:</strong> Methods that perform I/O operations
59 * require the {@link android.Manifest.permission#NFC} permission.
60 */
61public final class MifareUltralight extends BasicTagTechnology {
62    private static final String TAG = "NFC";
63
64    /** A MIFARE Ultralight compatible tag of unknown type */
65    public static final int TYPE_UNKNOWN = -1;
66    /** A MIFARE Ultralight tag */
67    public static final int TYPE_ULTRALIGHT = 1;
68    /** A MIFARE Ultralight C tag */
69    public static final int TYPE_ULTRALIGHT_C = 2;
70
71    /** Size of a MIFARE Ultralight page in bytes */
72    public static final int PAGE_SIZE = 4;
73
74    private static final int NXP_MANUFACTURER_ID = 0x04;
75    private static final int MAX_PAGE_COUNT = 256;
76
77    /** @hide */
78    public static final String EXTRA_IS_UL_C = "isulc";
79
80    private int mType;
81
82    /**
83     * Get an instance of {@link MifareUltralight} for the given tag.
84     * <p>Returns null if {@link MifareUltralight} was not enumerated in
85     * {@link Tag#getTechList} - this indicates the tag is not MIFARE
86     * Ultralight compatible, or that this Android
87     * device does not implement MIFARE Ultralight.
88     * <p>Does not cause any RF activity and does not block.
89     *
90     * @param tag an MIFARE Ultralight compatible tag
91     * @return MIFARE Ultralight object
92     */
93    public static MifareUltralight get(Tag tag) {
94        if (!tag.hasTech(TagTechnology.MIFARE_ULTRALIGHT)) return null;
95        try {
96            return new MifareUltralight(tag);
97        } catch (RemoteException e) {
98            return null;
99        }
100    }
101
102    /** @hide */
103    public MifareUltralight(Tag tag) throws RemoteException {
104        super(tag, TagTechnology.MIFARE_ULTRALIGHT);
105
106        // Check if this could actually be a MIFARE
107        NfcA a = NfcA.get(tag);
108
109        mType = TYPE_UNKNOWN;
110
111        if (a.getSak() == 0x00 && tag.getId()[0] == NXP_MANUFACTURER_ID) {
112            Bundle extras = tag.getTechExtras(TagTechnology.MIFARE_ULTRALIGHT);
113            if (extras.getBoolean(EXTRA_IS_UL_C)) {
114                mType = TYPE_ULTRALIGHT_C;
115            } else {
116                mType = TYPE_ULTRALIGHT;
117            }
118        }
119    }
120
121    /**
122     * Return the MIFARE Ultralight type of the tag.
123     * <p>One of {@link #TYPE_ULTRALIGHT} or {@link #TYPE_ULTRALIGHT_C} or
124     * {@link #TYPE_UNKNOWN}.
125     * <p>Depending on how the tag has been formatted, it can be impossible
126     * to accurately classify between original MIFARE Ultralight and
127     * Ultralight C. So treat this method as a hint.
128     * <p>Does not cause any RF activity and does not block.
129     *
130     * @return the type
131     */
132    public int getType() {
133        return mType;
134    }
135
136    /**
137     * Read 4 pages (16 bytes).
138     *
139     * <p>The MIFARE Ultralight protocol always reads 4 pages at a time, to
140     * reduce the number of commands required to read an entire tag.
141     * <p>If a read spans past the last readable block, then the tag will
142     * return pages that have been wrapped back to the first blocks. MIFARE
143     * Ultralight tags have readable blocks 0x00 through 0x0F. So a read to
144     * block offset 0x0E would return blocks 0x0E, 0x0F, 0x00, 0x01. MIFARE
145     * Ultralight C tags have readable blocks 0x00 through 0x2B. So a read to
146     * block 0x2A would return blocks 0x2A, 0x2B, 0x00, 0x01.
147     *
148     * <p>This is an I/O operation and will block until complete. It must
149     * not be called from the main application thread. A blocked call will be canceled with
150     * {@link IOException} if {@link #close} is called from another thread.
151     *
152     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
153     *
154     * @param pageOffset index of first page to read, starting from 0
155     * @return 4 pages (16 bytes)
156     * @throws TagLostException if the tag leaves the field
157     * @throws IOException if there is an I/O failure, or the operation is canceled
158     */
159    public byte[] readPages(int pageOffset) throws IOException {
160        validatePageIndex(pageOffset);
161        checkConnected();
162
163        byte[] cmd = { 0x30, (byte) pageOffset};
164        return transceive(cmd, false);
165    }
166
167    /**
168     * Write 1 page (4 bytes).
169     *
170     * <p>The MIFARE Ultralight protocol always writes 1 page at a time, to
171     * minimize EEPROM write cycles.
172     *
173     * <p>This is an I/O operation and will block until complete. It must
174     * not be called from the main application thread. A blocked call will be canceled with
175     * {@link IOException} if {@link #close} is called from another thread.
176     *
177     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
178     *
179     * @param pageOffset index of page to write, starting from 0
180     * @param data 4 bytes to write
181     * @throws TagLostException if the tag leaves the field
182     * @throws IOException if there is an I/O failure, or the operation is canceled
183     */
184    public void writePage(int pageOffset, byte[] data) throws IOException {
185        validatePageIndex(pageOffset);
186        checkConnected();
187
188        byte[] cmd = new byte[data.length + 2];
189        cmd[0] = (byte) 0xA2;
190        cmd[1] = (byte) pageOffset;
191        System.arraycopy(data, 0, cmd, 2, data.length);
192
193        transceive(cmd, false);
194    }
195
196    /**
197     * Send raw NfcA data to a tag and receive the response.
198     *
199     * <p>This is equivalent to connecting to this tag via {@link NfcA}
200     * and calling {@link NfcA#transceive}. Note that all MIFARE Classic
201     * tags are based on {@link NfcA} technology.
202     *
203     * <p>This is an I/O operation and will block until complete. It must
204     * not be called from the main application thread. A blocked call will be canceled with
205     * {@link IOException} if {@link #close} is called from another thread.
206     *
207     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
208     *
209     * @see NfcA#transceive
210     */
211    public byte[] transceive(byte[] data) throws IOException {
212        return transceive(data, true);
213    }
214
215    /**
216     * Set the timeout of {@link #transceive} in milliseconds.
217     * <p>The timeout only applies to MifareUltralight {@link #transceive},
218     * and is reset to a default value when {@link #close} is called.
219     * <p>Setting a longer timeout may be useful when performing
220     * transactions that require a long processing time on the tag
221     * such as key generation.
222     *
223     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
224     *
225     * @param timeout timeout value in milliseconds
226     * @hide
227     */
228    // TODO Unhide for ICS
229    public void setTimeout(int timeout) {
230        try {
231            int err = mTag.getTagService().setTimeout(
232                    TagTechnology.MIFARE_ULTRALIGHT, timeout);
233            if (err != ErrorCodes.SUCCESS) {
234                throw new IllegalArgumentException("The supplied timeout is not valid");
235            }
236        } catch (RemoteException e) {
237            Log.e(TAG, "NFC service dead", e);
238        }
239    }
240
241    /**
242     * Gets the currently set timeout of {@link #transceive} in milliseconds.
243     *
244     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
245     *
246     * @return timeout value in milliseconds
247     * @hide
248     */
249    // TODO Unhide for ICS
250    public int getTimeout() {
251        try {
252            return mTag.getTagService().getTimeout(TagTechnology.MIFARE_ULTRALIGHT);
253        } catch (RemoteException e) {
254            Log.e(TAG, "NFC service dead", e);
255            return 0;
256        }
257    }
258
259    private static void validatePageIndex(int pageIndex) {
260        // Do not be too strict on upper bounds checking, since some cards
261        // may have more addressable memory than they report.
262        // Note that issuing a command to an out-of-bounds block is safe - the
263        // tag will wrap the read to an addressable area. This validation is a
264        // helper to guard against obvious programming mistakes.
265        if (pageIndex < 0 || pageIndex >= MAX_PAGE_COUNT) {
266            throw new IndexOutOfBoundsException("page out of bounds: " + pageIndex);
267        }
268    }
269}
270