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