Java tutorial
/* * Copyright (C) 2010 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.nfc.tech; import android.nfc.ErrorCodes; import android.nfc.Tag; import android.nfc.TagLostException; import android.os.Bundle; import android.os.RemoteException; import android.util.Log; import java.io.IOException; //TOOD: Ultralight C 3-DES authentication, one-way counter /** * Provides access to MIFARE Ultralight properties and I/O operations on a {@link Tag}. * * <p>Acquire a {@link MifareUltralight} object using {@link #get}. * * <p>MIFARE Ultralight compatible tags have 4 byte pages {@link #PAGE_SIZE}. * The primary operations on an Ultralight tag are {@link #readPages} and * {@link #writePage}. * * <p>The original MIFARE Ultralight consists of a 64 byte EEPROM. The first * 4 pages are for the OTP area, manufacturer data, and locking bits. They are * readable and some bits are writable. The final 12 pages are the user * read/write area. For more information see the NXP data sheet MF0ICU1. * * <p>The MIFARE Ultralight C consists of a 192 byte EEPROM. The first 4 pages * are for OTP, manufacturer data, and locking bits. The next 36 pages are the * user read/write area. The next 4 pages are additional locking bits, counters * and authentication configuration and are readable. The final 4 pages are for * the authentication key and are not readable. For more information see the * NXP data sheet MF0ICU2. * * <p>Implementation of this class on a Android NFC device is optional. * If it is not implemented, then * {@link MifareUltralight} will never be enumerated in {@link Tag#getTechList}. * If it is enumerated, then all {@link MifareUltralight} I/O operations will be supported. * In either case, {@link NfcA} will also be enumerated on the tag, * because all MIFARE Ultralight tags are also {@link NfcA} tags. * * <p class="note"><strong>Note:</strong> Methods that perform I/O operations * require the {@link android.Manifest.permission#NFC} permission. */ public final class MifareUltralight extends BasicTagTechnology { private static final String TAG = "NFC"; /** A MIFARE Ultralight compatible tag of unknown type */ public static final int TYPE_UNKNOWN = -1; /** A MIFARE Ultralight tag */ public static final int TYPE_ULTRALIGHT = 1; /** A MIFARE Ultralight C tag */ public static final int TYPE_ULTRALIGHT_C = 2; /** Size of a MIFARE Ultralight page in bytes */ public static final int PAGE_SIZE = 4; private static final int NXP_MANUFACTURER_ID = 0x04; private static final int MAX_PAGE_COUNT = 256; /** @hide */ public static final String EXTRA_IS_UL_C = "isulc"; private int mType; /** * Get an instance of {@link MifareUltralight} for the given tag. * <p>Returns null if {@link MifareUltralight} was not enumerated in * {@link Tag#getTechList} - this indicates the tag is not MIFARE * Ultralight compatible, or that this Android * device does not implement MIFARE Ultralight. * <p>Does not cause any RF activity and does not block. * * @param tag an MIFARE Ultralight compatible tag * @return MIFARE Ultralight object */ public static MifareUltralight get(Tag tag) { if (!tag.hasTech(TagTechnology.MIFARE_ULTRALIGHT)) return null; try { return new MifareUltralight(tag); } catch (RemoteException e) { return null; } } /** @hide */ public MifareUltralight(Tag tag) throws RemoteException { super(tag, TagTechnology.MIFARE_ULTRALIGHT); // Check if this could actually be a MIFARE NfcA a = NfcA.get(tag); mType = TYPE_UNKNOWN; if (a.getSak() == 0x00 && tag.getId()[0] == NXP_MANUFACTURER_ID) { Bundle extras = tag.getTechExtras(TagTechnology.MIFARE_ULTRALIGHT); if (extras.getBoolean(EXTRA_IS_UL_C)) { mType = TYPE_ULTRALIGHT_C; } else { mType = TYPE_ULTRALIGHT; } } } /** * Return the MIFARE Ultralight type of the tag. * <p>One of {@link #TYPE_ULTRALIGHT} or {@link #TYPE_ULTRALIGHT_C} or * {@link #TYPE_UNKNOWN}. * <p>Depending on how the tag has been formatted, it can be impossible * to accurately classify between original MIFARE Ultralight and * Ultralight C. So treat this method as a hint. * <p>Does not cause any RF activity and does not block. * * @return the type */ public int getType() { return mType; } /** * Read 4 pages (16 bytes). * * <p>The MIFARE Ultralight protocol always reads 4 pages at a time, to * reduce the number of commands required to read an entire tag. * <p>If a read spans past the last readable block, then the tag will * return pages that have been wrapped back to the first blocks. MIFARE * Ultralight tags have readable blocks 0x00 through 0x0F. So a read to * block offset 0x0E would return blocks 0x0E, 0x0F, 0x00, 0x01. MIFARE * Ultralight C tags have readable blocks 0x00 through 0x2B. So a read to * block 0x2A would return blocks 0x2A, 0x2B, 0x00, 0x01. * * <p>This is an I/O operation and will block until complete. It must * not be called from the main application thread. A blocked call will be canceled with * {@link IOException} if {@link #close} is called from another thread. * * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission. * * @param pageOffset index of first page to read, starting from 0 * @return 4 pages (16 bytes) * @throws TagLostException if the tag leaves the field * @throws IOException if there is an I/O failure, or the operation is canceled */ public byte[] readPages(int pageOffset) throws IOException { validatePageIndex(pageOffset); checkConnected(); byte[] cmd = { 0x30, (byte) pageOffset }; return transceive(cmd, false); } /** * Write 1 page (4 bytes). * * <p>The MIFARE Ultralight protocol always writes 1 page at a time, to * minimize EEPROM write cycles. * * <p>This is an I/O operation and will block until complete. It must * not be called from the main application thread. A blocked call will be canceled with * {@link IOException} if {@link #close} is called from another thread. * * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission. * * @param pageOffset index of page to write, starting from 0 * @param data 4 bytes to write * @throws TagLostException if the tag leaves the field * @throws IOException if there is an I/O failure, or the operation is canceled */ public void writePage(int pageOffset, byte[] data) throws IOException { validatePageIndex(pageOffset); checkConnected(); byte[] cmd = new byte[data.length + 2]; cmd[0] = (byte) 0xA2; cmd[1] = (byte) pageOffset; System.arraycopy(data, 0, cmd, 2, data.length); transceive(cmd, false); } /** * Send raw NfcA data to a tag and receive the response. * * <p>This is equivalent to connecting to this tag via {@link NfcA} * and calling {@link NfcA#transceive}. Note that all MIFARE Classic * tags are based on {@link NfcA} technology. * * <p>Use {@link #getMaxTransceiveLength} to retrieve the maximum number of bytes * that can be sent with {@link #transceive}. * * <p>This is an I/O operation and will block until complete. It must * not be called from the main application thread. A blocked call will be canceled with * {@link IOException} if {@link #close} is called from another thread. * * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission. * * @see NfcA#transceive */ public byte[] transceive(byte[] data) throws IOException { return transceive(data, true); } /** * Return the maximum number of bytes that can be sent with {@link #transceive}. * @return the maximum number of bytes that can be sent with {@link #transceive}. */ public int getMaxTransceiveLength() { return getMaxTransceiveLengthInternal(); } /** * Set the {@link #transceive} timeout in milliseconds. * * <p>The timeout only applies to {@link #transceive} on this object, * and is reset to a default value when {@link #close} is called. * * <p>Setting a longer timeout may be useful when performing * transactions that require a long processing time on the tag * such as key generation. * * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission. * * @param timeout timeout value in milliseconds */ public void setTimeout(int timeout) { try { int err = mTag.getTagService().setTimeout(TagTechnology.MIFARE_ULTRALIGHT, timeout); if (err != ErrorCodes.SUCCESS) { throw new IllegalArgumentException("The supplied timeout is not valid"); } } catch (RemoteException e) { Log.e(TAG, "NFC service dead", e); } } /** * Get the current {@link #transceive} timeout in milliseconds. * * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission. * * @return timeout value in milliseconds */ public int getTimeout() { try { return mTag.getTagService().getTimeout(TagTechnology.MIFARE_ULTRALIGHT); } catch (RemoteException e) { Log.e(TAG, "NFC service dead", e); return 0; } } private static void validatePageIndex(int pageIndex) { // Do not be too strict on upper bounds checking, since some cards // may have more addressable memory than they report. // Note that issuing a command to an out-of-bounds block is safe - the // tag will wrap the read to an addressable area. This validation is a // helper to guard against obvious programming mistakes. if (pageIndex < 0 || pageIndex >= MAX_PAGE_COUNT) { throw new IndexOutOfBoundsException("page out of bounds: " + pageIndex); } } }