IsoDep.java revision a924973f22aedc580708625e4babb6deabc6b4d3
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.Tag; 20import android.os.Bundle; 21import android.os.RemoteException; 22import android.util.Log; 23 24import java.io.IOException; 25 26/** 27 * Provides access to ISO-DEP (ISO 14443-4) properties and I/O operations on a {@link Tag}. 28 * 29 * <p>Acquire an {@link IsoDep} object using {@link #get}. 30 * <p>The primary ISO-DEP I/O operation is {@link #transceive}. Applications must 31 * implement their own protocol stack on top of {@link #transceive}. 32 * <p>Tags that enumerate the {@link IsoDep} technology in {@link Tag#getTechList} 33 * will also enumerate 34 * {@link NfcA} or {@link NfcB} (since IsoDep builds on top of either of these). 35 * 36 * <p class="note"><strong>Note:</strong> Methods that perform I/O operations 37 * require the {@link android.Manifest.permission#NFC} permission. 38 */ 39public final class IsoDep extends BasicTagTechnology { 40 private static final String TAG = "NFC"; 41 42 /** @hide */ 43 public static final String EXTRA_HI_LAYER_RESP = "hiresp"; 44 /** @hide */ 45 public static final String EXTRA_HIST_BYTES = "histbytes"; 46 47 private byte[] mHiLayerResponse = null; 48 private byte[] mHistBytes = null; 49 50 /** 51 * Get an instance of {@link IsoDep} for the given tag. 52 * <p>Does not cause any RF activity and does not block. 53 * <p>Returns null if {@link IsoDep} was not enumerated in {@link Tag#getTechList}. 54 * This indicates the tag does not support ISO-DEP. 55 * 56 * @param tag an ISO-DEP compatible tag 57 * @return ISO-DEP object 58 */ 59 public static IsoDep get(Tag tag) { 60 if (!tag.hasTech(TagTechnology.ISO_DEP)) return null; 61 try { 62 return new IsoDep(tag); 63 } catch (RemoteException e) { 64 return null; 65 } 66 } 67 68 /** @hide */ 69 public IsoDep(Tag tag) 70 throws RemoteException { 71 super(tag, TagTechnology.ISO_DEP); 72 Bundle extras = tag.getTechExtras(TagTechnology.ISO_DEP); 73 if (extras != null) { 74 mHiLayerResponse = extras.getByteArray(EXTRA_HI_LAYER_RESP); 75 mHistBytes = extras.getByteArray(EXTRA_HIST_BYTES); 76 } 77 } 78 79 /** 80 * Set the timeout of {@link #transceive} in milliseconds. 81 * <p>The timeout only applies to ISO-DEP {@link #transceive}, and is 82 * reset to a default value when {@link #close} is called. 83 * <p>Setting a longer timeout may be useful when performing 84 * transactions that require a long processing time on the tag 85 * such as key generation. 86 * 87 * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission. 88 * 89 * @param timeout timeout value in milliseconds 90 */ 91 public void setTimeout(int timeout) { 92 try { 93 mTag.getTagService().setIsoDepTimeout(timeout); 94 } catch (RemoteException e) { 95 Log.e(TAG, "NFC service dead", e); 96 } 97 } 98 99 /** 100 * Return the ISO-DEP historical bytes for {@link NfcA} tags. 101 * <p>Does not cause any RF activity and does not block. 102 * <p>The historical bytes can be used to help identify a tag. They are present 103 * only on {@link IsoDep} tags that are based on {@link NfcA} RF technology. 104 * If this tag is not {@link NfcA} then null is returned. 105 * <p>In ISO 14443-4 terminology, the historical bytes are a subset of the RATS 106 * response. 107 * 108 * @return ISO-DEP historical bytes, or null if this is not a {@link NfcA} tag 109 */ 110 public byte[] getHistoricalBytes() { 111 return mHistBytes; 112 } 113 114 /** 115 * Return the higher layer response bytes for {@link NfcB} tags. 116 * <p>Does not cause any RF activity and does not block. 117 * <p>The higher layer response bytes can be used to help identify a tag. 118 * They are present only on {@link IsoDep} tags that are based on {@link NfcB} 119 * RF technology. If this tag is not {@link NfcB} then null is returned. 120 * <p>In ISO 14443-4 terminology, the higher layer bytes are a subset of the 121 * ATTRIB response. 122 * 123 * @return ISO-DEP historical bytes, or null if this is not a {@link NfcB} tag 124 */ 125 public byte[] getHiLayerResponse() { 126 return mHiLayerResponse; 127 } 128 129 /** 130 * Send raw ISO-DEP data to the tag and receive the response. 131 * 132 * <p>Applications must only send the INF payload, and not the start of frame and 133 * end of frame indicators. Applications do not need to fragment the payload, it 134 * will be automatically fragmented and defragmented by {@link #transceive} if 135 * it exceeds FSD/FSC limits. 136 * 137 * <p>This is an I/O operation and will block until complete. It must 138 * not be called from the main application thread. A blocked call will be canceled with 139 * {@link IOException} if {@link #close} is called from another thread. 140 * 141 * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission. 142 * 143 * @param data command bytes to send, must not be null 144 * @return response bytes received, will not be null 145 * @throws TagLostException if the tag leaves the field 146 * @throws IOException if there is an I/O failure, or this operation is canceled 147 */ 148 public byte[] transceive(byte[] data) throws IOException { 149 return transceive(data, true); 150 } 151} 152