/*
* 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);
}
}
}
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