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     * Get the current timeout for {@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     */
110    public int getTimeout() {
111        try {
112            return mTag.getTagService().getTimeout(TagTechnology.ISO_DEP);
113        } catch (RemoteException e) {
114            Log.e(TAG, "NFC service dead", e);
115            return 0;
116        }
117    }
118
119    /**
120     * Return the ISO-DEP historical bytes for {@link NfcA} tags.
121     * <p>Does not cause any RF activity and does not block.
122     * <p>The historical bytes can be used to help identify a tag. They are present
123     * only on {@link IsoDep} tags that are based on {@link NfcA} RF technology.
124     * If this tag is not {@link NfcA} then null is returned.
125     * <p>In ISO 14443-4 terminology, the historical bytes are a subset of the RATS
126     * response.
127     *
128     * @return ISO-DEP historical bytes, or null if this is not a {@link NfcA} tag
129     */
130    public byte[] getHistoricalBytes() {
131        return mHistBytes;
132    }
133
134    /**
135     * Return the higher layer response bytes for {@link NfcB} tags.
136     * <p>Does not cause any RF activity and does not block.
137     * <p>The higher layer response bytes can be used to help identify a tag.
138     * They are present only on {@link IsoDep} tags that are based on {@link NfcB}
139     * RF technology. If this tag is not {@link NfcB} then null is returned.
140     * <p>In ISO 14443-4 terminology, the higher layer bytes are a subset of the
141     * ATTRIB response.
142     *
143     * @return ISO-DEP historical bytes, or null if this is not a {@link NfcB} tag
144     */
145    public byte[] getHiLayerResponse() {
146        return mHiLayerResponse;
147    }
148
149    /**
150     * Send raw ISO-DEP data to the tag and receive the response.
151     *
152     * <p>Applications must only send the INF payload, and not the start of frame and
153     * end of frame indicators. Applications do not need to fragment the payload, it
154     * will be automatically fragmented and defragmented by {@link #transceive} if
155     * it exceeds FSD/FSC limits.
156     *
157     * <p>Use {@link #getMaxTransceiveLength} to retrieve the maximum number of bytes
158     * that can be sent with {@link #transceive}.
159     *
160     * <p>This is an I/O operation and will block until complete. It must
161     * not be called from the main application thread. A blocked call will be canceled with
162     * {@link IOException} if {@link #close} is called from another thread.
163     *
164     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
165     *
166     * @param data command bytes to send, must not be null
167     * @return response bytes received, will not be null
168     * @throws TagLostException if the tag leaves the field
169     * @throws IOException if there is an I/O failure, or this operation is canceled
170     */
171    public byte[] transceive(byte[] data) throws IOException {
172        return transceive(data, true);
173    }
174
175    /**
176     * Return the maximum number of bytes that can be sent with {@link #transceive}.
177     * @return the maximum number of bytes that can be sent with {@link #transceive}.
178     */
179    public int getMaxTransceiveLength() {
180        return getMaxTransceiveLengthInternal();
181    }
182
183    /**
184     * <p>Standard APDUs have a 1-byte length field, allowing a maximum of
185     * 255 payload bytes, which results in a maximum APDU length of 261 bytes.
186     *
187     * <p>Extended length APDUs have a 3-byte length field, allowing 65535
188     * payload bytes.
189     *
190     * <p>Some NFC adapters, like the one used in the Nexus S and the Galaxy Nexus
191     * do not support extended length APDUs. They are expected to be well-supported
192     * in the future though. Use this method to check for extended length APDU
193     * support.
194     *
195     * @return whether the NFC adapter on this device supports extended length APDUs.
196     */
197    public boolean isExtendedLengthApduSupported() {
198        try {
199            return mTag.getTagService().getExtendedLengthApdusSupported();
200        } catch (RemoteException e) {
201            Log.e(TAG, "NFC service dead", e);
202            return false;
203        }
204    }
205}
206