IsoDep.java revision faca12adc62d148505fadfd286e6a2752c197fa0 
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.os.Bundle;
22import android.os.RemoteException;
23import android.util.Log;
24
25import java.io.IOException;
26
27/**
28 * Provides access to ISO-DEP (ISO 14443-4) properties and I/O operations on a {@link Tag}.
29 *
30 * <p>Acquire an {@link IsoDep} object using {@link #get}.
31 * <p>The primary ISO-DEP I/O operation is {@link #transceive}. Applications must
32 * implement their own protocol stack on top of {@link #transceive}.
33 * <p>Tags that enumerate the {@link IsoDep} technology in {@link Tag#getTechList}
34 * will also enumerate
35 * {@link NfcA} or {@link NfcB} (since IsoDep builds on top of either of these).
36 *
37 * <p class="note"><strong>Note:</strong> Methods that perform I/O operations
38 * require the {@link android.Manifest.permission#NFC} permission.
39 */
40public final class IsoDep extends BasicTagTechnology {
41    private static final String TAG = "NFC";
42
43    /** @hide */
44    public static final String EXTRA_HI_LAYER_RESP = "hiresp";
45    /** @hide */
46    public static final String EXTRA_HIST_BYTES = "histbytes";
47
48    private byte[] mHiLayerResponse = null;
49    private byte[] mHistBytes = null;
50
51    /**
52     * Get an instance of {@link IsoDep} for the given tag.
53     * <p>Does not cause any RF activity and does not block.
54     * <p>Returns null if {@link IsoDep} was not enumerated in {@link Tag#getTechList}.
55     * This indicates the tag does not support ISO-DEP.
56     *
57     * @param tag an ISO-DEP compatible tag
58     * @return ISO-DEP object
59     */
60    public static IsoDep get(Tag tag) {
61        if (!tag.hasTech(TagTechnology.ISO_DEP)) return null;
62        try {
63            return new IsoDep(tag);
64        } catch (RemoteException e) {
65            return null;
66        }
67    }
68
69    /** @hide */
70    public IsoDep(Tag tag)
71            throws RemoteException {
72        super(tag, TagTechnology.ISO_DEP);
73        Bundle extras = tag.getTechExtras(TagTechnology.ISO_DEP);
74        if (extras != null) {
75            mHiLayerResponse = extras.getByteArray(EXTRA_HI_LAYER_RESP);
76            mHistBytes = extras.getByteArray(EXTRA_HIST_BYTES);
77        }
78    }
79
80    /**
81     * Set the timeout of {@link #transceive} in milliseconds.
82     * <p>The timeout only applies to ISO-DEP {@link #transceive}, and is
83     * reset to a default value when {@link #close} is called.
84     * <p>Setting a longer timeout may be useful when performing
85     * transactions that require a long processing time on the tag
86     * such as key generation.
87     *
88     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
89     *
90     * @param timeout timeout value in milliseconds
91     */
92    public void setTimeout(int timeout) {
93        try {
94            int err = mTag.getTagService().setTimeout(TagTechnology.ISO_DEP, timeout);
95            if (err != ErrorCodes.SUCCESS) {
96                throw new IllegalArgumentException("The supplied timeout is not valid");
97            }
98        } catch (RemoteException e) {
99            Log.e(TAG, "NFC service dead", e);
100        }
101    }
102
103    /**
104     * Gets the currently set timeout of {@link #transceive} in milliseconds.
105     *
106     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
107     *
108     * @return timeout value in milliseconds
109     * @hide
110     */
111    // TODO Unhide for ICS
112    public int getTimeout() {
113        try {
114            return mTag.getTagService().getTimeout(TagTechnology.ISO_DEP);
115        } catch (RemoteException e) {
116            Log.e(TAG, "NFC service dead", e);
117            return 0;
118        }
119    }
120
121    /**
122     * Return the ISO-DEP historical bytes for {@link NfcA} tags.
123     * <p>Does not cause any RF activity and does not block.
124     * <p>The historical bytes can be used to help identify a tag. They are present
125     * only on {@link IsoDep} tags that are based on {@link NfcA} RF technology.
126     * If this tag is not {@link NfcA} then null is returned.
127     * <p>In ISO 14443-4 terminology, the historical bytes are a subset of the RATS
128     * response.
129     *
130     * @return ISO-DEP historical bytes, or null if this is not a {@link NfcA} tag
131     */
132    public byte[] getHistoricalBytes() {
133        return mHistBytes;
134    }
135
136    /**
137     * Return the higher layer response bytes for {@link NfcB} tags.
138     * <p>Does not cause any RF activity and does not block.
139     * <p>The higher layer response bytes can be used to help identify a tag.
140     * They are present only on {@link IsoDep} tags that are based on {@link NfcB}
141     * RF technology. If this tag is not {@link NfcB} then null is returned.
142     * <p>In ISO 14443-4 terminology, the higher layer bytes are a subset of the
143     * ATTRIB response.
144     *
145     * @return ISO-DEP historical bytes, or null if this is not a {@link NfcB} tag
146     */
147    public byte[] getHiLayerResponse() {
148        return mHiLayerResponse;
149    }
150
151    /**
152     * Send raw ISO-DEP data to the tag and receive the response.
153     *
154     * <p>Applications must only send the INF payload, and not the start of frame and
155     * end of frame indicators. Applications do not need to fragment the payload, it
156     * will be automatically fragmented and defragmented by {@link #transceive} if
157     * it exceeds FSD/FSC limits.
158     *
159     * <p>Use {@link #getMaxTransceiveLength} to retrieve the maximum number of bytes
160     * that can be sent with {@link #transceive}.
161     *
162     * <p>This is an I/O operation and will block until complete. It must
163     * not be called from the main application thread. A blocked call will be canceled with
164     * {@link IOException} if {@link #close} is called from another thread.
165     *
166     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
167     *
168     * @param data command bytes to send, must not be null
169     * @return response bytes received, will not be null
170     * @throws TagLostException if the tag leaves the field
171     * @throws IOException if there is an I/O failure, or this operation is canceled
172     */
173    public byte[] transceive(byte[] data) throws IOException {
174        return transceive(data, true);
175    }
176
177    /**
178     * Return the maximum number of bytes that can be sent with {@link #transceive}.
179     * @return the maximum number of bytes that can be sent with {@link #transceive}.
180     */
181    public int getMaxTransceiveLength() {
182        return getMaxTransceiveLengthInternal();
183    }
184}
185