content: /*
   * 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.RemoteException;
  import android.util.Log;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  
  /**
   * Provides access to MIFARE Classic properties and I/O operations on a {@link Tag}.
   *
   * <p>Acquire a {@link MifareClassic} object using {@link #get}.
   *
   * <p>MIFARE Classic is also known as MIFARE Standard.
   * <p>MIFARE Classic tags are divided into sectors, and each sector is sub-divided into
   * blocks. Block size is always 16 bytes ({@link #BLOCK_SIZE}. Sector size varies.
   * <ul>
   * <li>MIFARE Classic Mini are 320 bytes ({@link #SIZE_MINI}), with 5 sectors each of 4 blocks.
   * <li>MIFARE Classic 1k are 1024 bytes ({@link #SIZE_1K}), with 16 sectors each of 4 blocks.
   * <li>MIFARE Classic 2k are 2048 bytes ({@link #SIZE_2K}), with 32 sectors each of 4 blocks.
   * <li>MIFARE Classic 4k are 4096 bytes ({@link #SIZE_4K}). The first 32 sectors contain 4 blocks
   * and the last 8 sectors contain 16 blocks.
   * </ul>
   *
   * <p>MIFARE Classic tags require authentication on a per-sector basis before any
   * other I/O operations on that sector can be performed. There are two keys per sector,
   * and ACL bits determine what I/O operations are allowed on that sector after
   * authenticating with a key. {@see #authenticateSectorWithKeyA} and
   * {@see #authenticateSectorWithKeyB}.
   *
   * <p>Three well-known authentication keys are defined in this class:
   * {@link #KEY_DEFAULT}, {@link #KEY_MIFARE_APPLICATION_DIRECTORY},
   * {@link #KEY_NFC_FORUM}.
   * <ul>
   * <li>{@link #KEY_DEFAULT} is the default factory key for MIFARE Classic.
   * <li>{@link #KEY_MIFARE_APPLICATION_DIRECTORY} is the well-known key for
   * MIFARE Classic cards that have been formatted according to the
   * MIFARE Application Directory (MAD) specification.
   * <li>{@link #KEY_NFC_FORUM} is the well-known key for MIFARE Classic cards that
   * have been formatted according to the NXP specification for NDEF on MIFARE Classic.
   *
   * <p>Implementation of this class on a Android NFC device is optional.
   * If it is not implemented, then
   * {@link MifareClassic} will never be enumerated in {@link Tag#getTechList}.
   * If it is enumerated, then all {@link MifareClassic} I/O operations will be supported,
   * and {@link Ndef#MIFARE_CLASSIC} NDEF tags will also be supported. In either case,
   * {@link NfcA} will also be enumerated on the tag, because all MIFARE Classic tags are also
   * {@link NfcA}.
   *
   * <p class="note"><strong>Note:</strong> Methods that perform I/O operations
   * require the {@link android.Manifest.permission#NFC} permission.
   */
  public final class MifareClassic extends BasicTagTechnology {
      private static final String TAG = "NFC";
  
      /**
       * The default factory key.
       */
      public static final byte[] KEY_DEFAULT =
              {(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF};
      /**
       * The well-known key for tags formatted according to the
       * MIFARE Application Directory (MAD) specification.
       */
      public static final byte[] KEY_MIFARE_APPLICATION_DIRECTORY =
              {(byte)0xA0,(byte)0xA1,(byte)0xA2,(byte)0xA3,(byte)0xA4,(byte)0xA5};
      /**
       * The well-known key for tags formatted according to the
       * NDEF on MIFARE Classic specification.
       */
      public static final byte[] KEY_NFC_FORUM =
              {(byte)0xD3,(byte)0xF7,(byte)0xD3,(byte)0xF7,(byte)0xD3,(byte)0xF7};
  
      /** A MIFARE Classic compatible card of unknown type */
      public static final int TYPE_UNKNOWN = -1;
      /** A MIFARE Classic tag */
      public static final int TYPE_CLASSIC = 0;
      /** A MIFARE Plus tag */
      public static final int TYPE_PLUS = 1;
      /** A MIFARE Pro tag */
      public static final int TYPE_PRO = 2;
  
      /** Tag contains 16 sectors, each with 4 blocks. */
      public static final int SIZE_1K = 1024;
      /** Tag contains 32 sectors, each with 4 blocks. */
      public static final int SIZE_2K = 2048;
      /**
       * Tag contains 40 sectors. The first 32 sectors contain 4 blocks and the last 8 sectors
       * contain 16 blocks.
       */
      public static final int SIZE_4K = 4096;
      /** Tag contains 5 sectors, each with 4 blocks. */
      public static final int SIZE_MINI = 320;
  
      /** Size of a MIFARE Classic block (in bytes) */
      public static final int BLOCK_SIZE = 16;
  
      private static final int MAX_BLOCK_COUNT = 256;
      private static final int MAX_SECTOR_COUNT = 40;
  
      private boolean mIsEmulated;
      private int mType;
      private int mSize;
  
      /**
       * Get an instance of {@link MifareClassic} for the given tag.
       * <p>Does not cause any RF activity and does not block.
       * <p>Returns null if {@link MifareClassic} was not enumerated in {@link Tag#getTechList}.
       * This indicates the tag is not MIFARE Classic compatible, or this Android
       * device does not support MIFARE Classic.
       *
       * @param tag an MIFARE Classic compatible tag
       * @return MIFARE Classic object
       */
      public static MifareClassic get(Tag tag) {
          if (!tag.hasTech(TagTechnology.MIFARE_CLASSIC)) return null;
          try {
              return new MifareClassic(tag);
          } catch (RemoteException e) {
              return null;
          }
      }
  
      /** @hide */
      public MifareClassic(Tag tag) throws RemoteException {
          super(tag, TagTechnology.MIFARE_CLASSIC);
  
          NfcA a = NfcA.get(tag);  // MIFARE Classic is always based on NFC a
  
          mIsEmulated = false;
  
          switch (a.getSak()) {
          case 0x01:
          case 0x08:
              mType = TYPE_CLASSIC;
              mSize = SIZE_1K;
              break;
          case 0x09:
              mType = TYPE_CLASSIC;
              mSize = SIZE_MINI;
              break;
          case 0x10:
              mType = TYPE_PLUS;
              mSize = SIZE_2K;
              // SecLevel = SL2
              break;
          case 0x11:
              mType = TYPE_PLUS;
              mSize = SIZE_4K;
              // Seclevel = SL2
              break;
          case 0x18:
              mType = TYPE_CLASSIC;
              mSize = SIZE_4K;
              break;
          case 0x28:
              mType = TYPE_CLASSIC;
              mSize = SIZE_1K;
              mIsEmulated = true;
              break;
          case 0x38:
              mType = TYPE_CLASSIC;
              mSize = SIZE_4K;
              mIsEmulated = true;
              break;
          case 0x88:
              mType = TYPE_CLASSIC;
              mSize = SIZE_1K;
              // NXP-tag: false
              break;
          case 0x98:
          case 0xB8:
              mType = TYPE_PRO;
              mSize = SIZE_4K;
              break;
          default:
              // Stack incorrectly reported a MifareClassic. We cannot handle this
              // gracefully - we have no idea of the memory layout. Bail.
              throw new RuntimeException(
                      "Tag incorrectly enumerated as MIFARE Classic, SAK = " + a.getSak());
          }
      }
  
      /**
       * Return the type of this MIFARE Classic compatible tag.
       * <p>One of {@link #TYPE_UNKNOWN}, {@link #TYPE_CLASSIC}, {@link #TYPE_PLUS} or
       * {@link #TYPE_PRO}.
       * <p>Does not cause any RF activity and does not block.
       *
       * @return type
       */
      public int getType() {
          return mType;
      }
  
      /**
       * Return the size of the tag in bytes
       * <p>One of {@link #SIZE_MINI}, {@link #SIZE_1K}, {@link #SIZE_2K}, {@link #SIZE_4K}.
       * These constants are equal to their respective size in bytes.
       * <p>Does not cause any RF activity and does not block.
       * @return size in bytes
       */
      public int getSize() {
          return mSize;
      }
  
      /**
       * Return true if the tag is emulated, determined at discovery time.
       * These are actually smart-cards that emulate a MIFARE Classic interface.
       * They can be treated identically to a MIFARE Classic tag.
       * @hide
       */
      public boolean isEmulated() {
          return mIsEmulated;
      }
  
      /**
       * Return the number of MIFARE Classic sectors.
       * <p>Does not cause any RF activity and does not block.
       * @return number of sectors
       */
      public int getSectorCount() {
          switch (mSize) {
          case SIZE_1K:
              return 16;
          case SIZE_2K:
              return 32;
          case SIZE_4K:
              return 40;
          case SIZE_MINI:
              return 5;
          default:
              return 0;
          }
      }
  
      /**
       * Return the total number of MIFARE Classic blocks.
       * <p>Does not cause any RF activity and does not block.
       * @return total number of blocks
       */
      public int getBlockCount() {
          return mSize / BLOCK_SIZE;
      }
  
      /**
       * Return the number of blocks in the given sector.
       * <p>Does not cause any RF activity and does not block.
       *
       * @param sectorIndex index of sector, starting from 0
       * @return number of blocks in the sector
       */
      public int getBlockCountInSector(int sectorIndex) {
          validateSector(sectorIndex);
  
          if (sectorIndex < 32) {
              return 4;
          } else {
              return 16;
          }
      }
  
      /**
       * Return the sector that contains a given block.
       * <p>Does not cause any RF activity and does not block.
       *
       * @param blockIndex index of block to lookup, starting from 0
       * @return sector index that contains the block
       */
      public int blockToSector(int blockIndex) {
          validateBlock(blockIndex);
  
          if (blockIndex < 32 * 4) {
              return blockIndex / 4;
          } else {
              return 32 + (blockIndex - 32 * 4) / 16;
          }
      }
  
      /**
       * Return the first block of a given sector.
       * <p>Does not cause any RF activity and does not block.
       *
       * @param sectorIndex index of sector to lookup, starting from 0
       * @return block index of first block in sector
       */
      public int sectorToBlock(int sectorIndex) {
          if (sectorIndex < 32) {
              return sectorIndex * 4;
          } else {
              return 32 * 4 + (sectorIndex - 32) * 16;
          }
      }
  
      /**
       * Authenticate a sector with key A.
       *
       * <p>Successful authentication of a sector with key A enables other
       * I/O operations on that sector. The set of operations granted by key A
       * key depends on the ACL bits set in that sector. For more information
       * see the MIFARE Classic specification on <a href="http://www.nxp.com">http://www.nxp.com</a>.
       *
       * <p>A failed authentication attempt causes an implicit reconnection to the
       * tag, so authentication to other sectors will be lost.
       *
       * <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 sectorIndex index of sector to authenticate, starting from 0
       * @param key 6-byte authentication key
       * @return true on success, false on authentication failure
       * @throws TagLostException if the tag leaves the field
       * @throws IOException if there is an I/O failure, or the operation is canceled
       */
      public boolean authenticateSectorWithKeyA(int sectorIndex, byte[] key) throws IOException {
          return authenticate(sectorIndex, key, true);
      }
  
      /**
       * Authenticate a sector with key B.
       *
       * <p>Successful authentication of a sector with key B enables other
       * I/O operations on that sector. The set of operations granted by key B
       * depends on the ACL bits set in that sector. For more information
       * see the MIFARE Classic specification on <a href="http://www.nxp.com">http://www.nxp.com</a>.
       *
       * <p>A failed authentication attempt causes an implicit reconnection to the
       * tag, so authentication to other sectors will be lost.
       *
       * <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 sectorIndex index of sector to authenticate, starting from 0
       * @param key 6-byte authentication key
       * @return true on success, false on authentication failure
       * @throws TagLostException if the tag leaves the field
       * @throws IOException if there is an I/O failure, or the operation is canceled
       */
      public boolean authenticateSectorWithKeyB(int sectorIndex, byte[] key) throws IOException {
          return authenticate(sectorIndex, key, false);
      }
  
      private boolean authenticate(int sector, byte[] key, boolean keyA) throws IOException {
          validateSector(sector);
          checkConnected();
  
          byte[] cmd = new byte[12];
  
          // First byte is the command
          if (keyA) {
              cmd[0] = 0x60; // phHal_eMifareAuthentA
          } else {
              cmd[0] = 0x61; // phHal_eMifareAuthentB
          }
  
          // Second byte is block address
          // Authenticate command takes a block address. Authenticating a block
          // of a sector will authenticate the entire sector.
          cmd[1] = (byte) sectorToBlock(sector);
  
          // Next 4 bytes are last 4 bytes of UID
          byte[] uid = getTag().getId();
          System.arraycopy(uid, uid.length - 4, cmd, 2, 4);
  
          // Next 6 bytes are key
          System.arraycopy(key, 0, cmd, 6, 6);
  
          try {
              if (transceive(cmd, false) != null) {
                  return true;
              }
          } catch (TagLostException e) {
              throw e;
          } catch (IOException e) {
              // No need to deal with, will return false anyway
          }
          return false;
      }
  
      /**
       * Read 16-byte block.
       *
       * <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 blockIndex index of block to read, starting from 0
       * @return 16 byte block
       * @throws TagLostException if the tag leaves the field
       * @throws IOException if there is an I/O failure, or the operation is canceled
       */
      public byte[] readBlock(int blockIndex) throws IOException {
          validateBlock(blockIndex);
          checkConnected();
  
          byte[] cmd = { 0x30, (byte) blockIndex };
          return transceive(cmd, false);
      }
  
      /**
       * Write 16-byte block.
       *
       * <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 blockIndex index of block to write, starting from 0
       * @param data 16 bytes of data 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 writeBlock(int blockIndex, byte[] data) throws IOException {
          validateBlock(blockIndex);
          checkConnected();
          if (data.length != 16) {
              throw new IllegalArgumentException("must write 16-bytes");
          }
  
          byte[] cmd = new byte[data.length + 2];
          cmd[0] = (byte) 0xA0; // MF write command
          cmd[1] = (byte) blockIndex;
          System.arraycopy(data, 0, cmd, 2, data.length);
  
          transceive(cmd, false);
      }
  
      /**
       * Increment a value block, storing the result in the temporary block on the tag.
       *
       * <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 blockIndex index of block to increment, starting from 0
       * @param value non-negative to increment by
       * @throws TagLostException if the tag leaves the field
       * @throws IOException if there is an I/O failure, or the operation is canceled
       */
      public void increment(int blockIndex, int value) throws IOException {
          validateBlock(blockIndex);
          validateValueOperand(value);
          checkConnected();
  
          ByteBuffer cmd = ByteBuffer.allocate(6);
          cmd.order(ByteOrder.LITTLE_ENDIAN);
          cmd.put( (byte) 0xC1 );
          cmd.put( (byte) blockIndex );
          cmd.putInt(value);
  
          transceive(cmd.array(), false);
      }
  
      /**
       * Decrement a value block, storing the result in the temporary block on the tag.
       *
       * <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 blockIndex index of block to decrement, starting from 0
       * @param value non-negative to decrement by
       * @throws TagLostException if the tag leaves the field
       * @throws IOException if there is an I/O failure, or the operation is canceled
       */
      public void decrement(int blockIndex, int value) throws IOException {
          validateBlock(blockIndex);
          validateValueOperand(value);
          checkConnected();
  
          ByteBuffer cmd = ByteBuffer.allocate(6);
          cmd.order(ByteOrder.LITTLE_ENDIAN);
          cmd.put( (byte) 0xC0 );
          cmd.put( (byte) blockIndex );
          cmd.putInt(value);
  
          transceive(cmd.array(), false);
      }
  
      /**
       * Copy from the temporary block to a value block.
       *
       * <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 blockIndex index of block to copy to
       * @throws TagLostException if the tag leaves the field
       * @throws IOException if there is an I/O failure, or the operation is canceled
       */
      public void transfer(int blockIndex) throws IOException {
          validateBlock(blockIndex);
          checkConnected();
  
          byte[] cmd = { (byte) 0xB0, (byte) blockIndex };
  
          transceive(cmd, false);
      }
  
      /**
       * Copy from a value block to the temporary block.
       *
       * <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 blockIndex index of block to copy from
       * @throws TagLostException if the tag leaves the field
       * @throws IOException if there is an I/O failure, or the operation is canceled
       */
      public void restore(int blockIndex) throws IOException {
          validateBlock(blockIndex);
          checkConnected();
  
          byte[] cmd = { (byte) 0xC2, (byte) blockIndex };
  
          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_CLASSIC, 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_CLASSIC);
          } catch (RemoteException e) {
              Log.e(TAG, "NFC service dead", e);
              return 0;
          }
      }
  
      private static void validateSector(int sector) {
          // Do not be too strict on upper bounds checking, since some cards
          // have more addressable memory than they report. For example,
          // MIFARE Plus 2k cards will appear as MIFARE Classic 1k cards when in
          // MIFARE Classic compatibility mode.
          // Note that issuing a command to an out-of-bounds block is safe - the
          // tag should report error causing IOException. This validation is a
          // helper to guard against obvious programming mistakes.
          if (sector < 0 || sector >= MAX_SECTOR_COUNT) {
              throw new IndexOutOfBoundsException("sector out of bounds: " + sector);
          }
      }
  
      private static void validateBlock(int block) {
          // Just looking for obvious out of bounds...
          if (block < 0 || block >= MAX_BLOCK_COUNT) {
              throw new IndexOutOfBoundsException("block out of bounds: " + block);
          }
      }
  
      private static void validateValueOperand(int value) {
          if (value < 0) {
              throw new IllegalArgumentException("value operand negative");
          }
      }
  }
  