https://source.android.com/ 
/*
 * Copyright (C) 2017 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.
 */
/*
 * Copyright (c) 2015-2017, The Linux Foundation.
 */
/*
 * Contributed by: Giesecke & Devrient GmbH.
 */

package android.se.omapi;

import android.annotation.NonNull;
import android.annotation.Nullable;
import android.os.RemoteException;
import android.os.ServiceSpecificException;
import android.util.Log;

import java.io.IOException;


Instances of this class represent an ISO/IEC 7816-4 channel opened to a
Secure Element. It can be either a logical channel or the basic channel. They
can be used to send APDUs to the secure element. Channels are opened by
calling the Session.openBasicChannel(byte[]) or
Session.openLogicalChannel(byte[]) methods.

See Also:
/**
 * Instances of this class represent an ISO/IEC 7816-4 channel opened to a
 * Secure Element. It can be either a logical channel or the basic channel. They
 * can be used to send APDUs to the secure element. Channels are opened by
 * calling the Session.openBasicChannel(byte[]) or
 * Session.openLogicalChannel(byte[]) methods.
 *
 * @see <a href="http://globalplatform.org">GlobalPlatform Open Mobile API</a>
 */
public final class Channel implements java.nio.channels.Channel {

    private static final String TAG = "OMAPI.Channel";
    private Session mSession;
    private final ISecureElementChannel mChannel;
    private final SEService mService;
    private final Object mLock = new Object();

    Channel(@NonNull SEService service, @NonNull Session session,
            @NonNull ISecureElementChannel channel) {
        if (service == null || session == null || channel == null) {
            throw new IllegalArgumentException("Parameters cannot be null");
        }
        mService = service;
        mSession = session;
        mChannel = channel;
    }

    
Closes this channel to the Secure Element. If the method is called when
the channel is already closed, this method will be ignored. The close()
method shall wait for completion of any pending transmit(byte[] command)
before closing the channel.

/**
     * Closes this channel to the Secure Element. If the method is called when
     * the channel is already closed, this method will be ignored. The close()
     * method shall wait for completion of any pending transmit(byte[] command)
     * before closing the channel.
     */
    public void close() {
        if (isOpen()) {
            synchronized (mLock) {
                try {
                    mChannel.close();
                } catch (Exception e) {
                    Log.e(TAG, "Error closing channel", e);
                }
            }
        }
    }

    
Tells if this channel is open.

Returns:false if the channel is closed or in case of an error.
        true otherwise.
/**
     * Tells if this channel is open.
     *
     * @return <code>false</code> if the channel is closed or in case of an error.
     *         <code>true</code> otherwise.
     */
    public boolean isOpen() {
        if (!mService.isConnected()) {
            Log.e(TAG, "service not connected to system");
            return false;
        }
        try {
            return !mChannel.isClosed();
        } catch (RemoteException e) {
            Log.e(TAG, "Exception in isClosed()");
            return false;
        }
    }

    
Returns a boolean telling if this channel is the basic channel.

Returns:true if this channel is a basic channel. false if
        this channel is a logical channel.
/**
     * Returns a boolean telling if this channel is the basic channel.
     *
     * @return <code>true</code> if this channel is a basic channel. <code>false</code> if
     *         this channel is a logical channel.
     */
    public boolean isBasicChannel() {
        if (!mService.isConnected()) {
            throw new IllegalStateException("service not connected to system");
        }
        try {
            return mChannel.isBasicChannel();
        } catch (RemoteException e) {
            throw new IllegalStateException(e.getMessage());
        }
    }

    
Transmit an APDU command (as per ISO/IEC 7816-4) to the Secure Element. The
underlying layers generate as many TPDUs as necessary to transport this APDU. The
API shall ensure that all available data returned from Secure Element, including
concatenated responses, are retrieved and made available to the calling application. If a
warning status code is received the API wont check for further response data but will
return all data received so far and the warning status code.

The transport part is invisible from the application. The generated response is the
response of the APDU which means that all protocols related responses are handled
inside the API or the underlying implementation.

The transmit method shall support extended length APDU commands independently of
the coding within the ATR.

For status word '61 XX' the API or underlying implementation shall issue a GET
RESPONSE command as specified by ISO 7816-4 standard with LE=XX; for the status
word '6C XX', the API or underlying implementation shall reissue the input command
with LE=XX. For other status words, the API (or underlying implementation) shall return
the complete response including data and status word to the device application. The API
(or underlying implementation) shall not handle internally the received status words. The
channel shall not be closed even if the Secure Element answered with an error code.
The system ensures the synchronization between all the concurrent calls to this method,
and that only one APDU will be sent at a time, irrespective of the number of TPDUs that
might be required to transport it to the SE. The entire APDU communication to this SE is
locked to the APDU.

The channel information in the class byte in the APDU will be ignored. The system will
add any required information to ensure the APDU is transported on this channel.
The only restrictions on the set of commands that can be sent is defined below, the API
implementation shall be able to send all other commands: 


    

  • MANAGE_CHANNEL commands are not allowed.
    • 

  • SELECT by DF Name (p1=04) are not allowed.
    • 

  • CLA bytes with channel numbers are de-masked.
    • 



Params:
  • command – the APDU command to be transmitted, as a byte array.
Throws:
Returns:the response received, as a byte array. The returned byte array contains the data
bytes in the following order:
[<first data byte>, ..., <last data byte>, <sw1>, <sw2>]
/**
     * Transmit an APDU command (as per ISO/IEC 7816-4) to the Secure Element. The
     * underlying layers generate as many TPDUs as necessary to transport this APDU. The
     * API shall ensure that all available data returned from Secure Element, including
     * concatenated responses, are retrieved and made available to the calling application. If a
     * warning status code is received the API wont check for further response data but will
     * return all data received so far and the warning status code.<br>
     * The transport part is invisible from the application. The generated response is the
     * response of the APDU which means that all protocols related responses are handled
     * inside the API or the underlying implementation.<br>
     * The transmit method shall support extended length APDU commands independently of
     * the coding within the ATR.<br>
     * For status word '61 XX' the API or underlying implementation shall issue a GET
     * RESPONSE command as specified by ISO 7816-4 standard with LE=XX; for the status
     * word '6C XX', the API or underlying implementation shall reissue the input command
     * with LE=XX. For other status words, the API (or underlying implementation) shall return
     * the complete response including data and status word to the device application. The API
     * (or underlying implementation) shall not handle internally the received status words. The
     * channel shall not be closed even if the Secure Element answered with an error code.
     * The system ensures the synchronization between all the concurrent calls to this method,
     * and that only one APDU will be sent at a time, irrespective of the number of TPDUs that
     * might be required to transport it to the SE. The entire APDU communication to this SE is
     * locked to the APDU.<br>
     * The channel information in the class byte in the APDU will be ignored. The system will
     * add any required information to ensure the APDU is transported on this channel.
     * The only restrictions on the set of commands that can be sent is defined below, the API
     * implementation shall be able to send all other commands: <br>
     * <ul>
     * <li>MANAGE_CHANNEL commands are not allowed.</li>
     * <li>SELECT by DF Name (p1=04) are not allowed.</li>
     * <li>CLA bytes with channel numbers are de-masked.</li>
     * </ul>
     *
     * @param command the APDU command to be transmitted, as a byte array.
     *
     * @return the response received, as a byte array. The returned byte array contains the data
     * bytes in the following order:
     * [&lt;first data byte&gt;, ..., &lt;last data byte&gt;, &lt;sw1&gt;, &lt;sw2&gt;]
     *
     * @throws IOException if there is a communication problem to the reader or the Secure Element.
     * @throws IllegalStateException if the channel is used after being closed.
     * @throws IllegalArgumentException if the command byte array is less than 4 bytes long.
     * @throws IllegalArgumentException if Lc byte is inconsistent with length of the byte array.
     * @throws IllegalArgumentException if CLA byte is invalid according to [2] (0xff).
     * @throws IllegalArgumentException if INS byte is invalid according to [2] (0x6x or 0x9x).
     * @throws SecurityException if the command is filtered by the security policy.
     * @throws NullPointerException if command is NULL.
     */
    public @NonNull byte[] transmit(@NonNull byte[] command) throws IOException {
        if (!mService.isConnected()) {
            throw new IllegalStateException("service not connected to system");
        }
        synchronized (mLock) {
            try {
                byte[] response = mChannel.transmit(command);
                if (response == null) {
                    throw new IOException("Error in communicating with Secure Element");
                }
                return response;
            } catch (ServiceSpecificException e) {
                throw new IOException(e.getMessage());
            } catch (RemoteException e) {
                throw new IllegalStateException(e.getMessage());
            }
        }
    }

    
Get the session that has opened this channel.

Returns:the session object this channel is bound to.
/**
     * Get the session that has opened this channel.
     *
     * @return the session object this channel is bound to.
     */
    public @NonNull Session getSession() {
        return mSession;
    }

    
Returns the data as received from the application select command inclusively the status word
received at applet selection.
The returned byte array contains the data bytes in the following order:
[<first data byte>, ..., <last data byte>, <sw1>, <sw2>]

Returns:The data as returned by the application select command inclusively the status word.
Only the status word if the application select command has no returned data.
Returns null if an application select command has not been performed or the selection
response can not be retrieved by the reader implementation.
/**
     * Returns the data as received from the application select command inclusively the status word
     * received at applet selection.
     * The returned byte array contains the data bytes in the following order:
     * [&lt;first data byte&gt;, ..., &lt;last data byte&gt;, &lt;sw1&gt;, &lt;sw2&gt;]
     * @return The data as returned by the application select command inclusively the status word.
     * Only the status word if the application select command has no returned data.
     * Returns null if an application select command has not been performed or the selection
     * response can not be retrieved by the reader implementation.
     */
    public @Nullable byte[] getSelectResponse() {
        if (!mService.isConnected()) {
            throw new IllegalStateException("service not connected to system");
        }

        byte[] response;
        try {
            response = mChannel.getSelectResponse();
        } catch (RemoteException e) {
            throw new IllegalStateException(e.getMessage());
        }

        if (response != null && response.length == 0) {
            response = null;
        }
        return response;
    }

    
Performs a selection of the next Applet on this channel that matches to the partial AID
specified in the openBasicChannel(byte[] aid) or openLogicalChannel(byte[] aid) method.
This mechanism can be used by a device application to iterate through all Applets
matching to the same partial AID.
If selectNext() returns true a new Applet was successfully selected on this channel.
If no further Applet exists with matches to the partial AID this method returns false
and the already selected Applet stays selected. 

Since the API cannot distinguish between a partial and full AID the API shall rely on the
response of the Secure Element for the return value of this method. 

The implementation of the underlying SELECT command within this method shall use
the same values as the corresponding openBasicChannel(byte[] aid) or
openLogicalChannel(byte[] aid) command with the option: 

P2='02' (Next occurrence) 

The select response stored in the Channel object shall be updated with the APDU
response of the SELECT command.

Throws:
Returns:true if new Applet was selected on this channel.
false he already selected Applet stays selected on this channel.
/**
     * Performs a selection of the next Applet on this channel that matches to the partial AID
     * specified in the openBasicChannel(byte[] aid) or openLogicalChannel(byte[] aid) method.
     * This mechanism can be used by a device application to iterate through all Applets
     * matching to the same partial AID.
     * If selectNext() returns true a new Applet was successfully selected on this channel.
     * If no further Applet exists with matches to the partial AID this method returns false
     * and the already selected Applet stays selected. <br>
     *
     * Since the API cannot distinguish between a partial and full AID the API shall rely on the
     * response of the Secure Element for the return value of this method. <br>
     * The implementation of the underlying SELECT command within this method shall use
     * the same values as the corresponding openBasicChannel(byte[] aid) or
     * openLogicalChannel(byte[] aid) command with the option: <br>
     * P2='02' (Next occurrence) <br>
     * The select response stored in the Channel object shall be updated with the APDU
     * response of the SELECT command.

     * @return <code>true</code> if new Applet was selected on this channel.
               <code>false</code> he already selected Applet stays selected on this channel.
     *
     * @throws IOException if there is a communication problem to the reader or the Secure Element.
     * @throws IllegalStateException if the channel is used after being closed.
     * @throws UnsupportedOperationException if this operation is not supported by the card.
     */
    public boolean selectNext() throws IOException {
        if (!mService.isConnected()) {
            throw new IllegalStateException("service not connected to system");
        }
        try {
            synchronized (mLock) {
                return mChannel.selectNext();
            }
        } catch (ServiceSpecificException e) {
            throw new IOException(e.getMessage());
        } catch (RemoteException e) {
            throw new IllegalStateException(e.getMessage());
        }
    }
}