/*
* 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.os.Bundle;
import android.os.RemoteException;
import android.util.Log;
import java.io.IOException;
/**
* Provides access to ISO-DEP (ISO 14443-4) properties and I/O operations on a {@link Tag}.
*
* <p>Acquire an {@link IsoDep} object using {@link #get}.
* <p>The primary ISO-DEP I/O operation is {@link #transceive}. Applications must
* implement their own protocol stack on top of {@link #transceive}.
* <p>Tags that enumerate the {@link IsoDep} technology in {@link Tag#getTechList}
* will also enumerate
* {@link NfcA} or {@link NfcB} (since IsoDep builds on top of either of these).
*
* <p class="note"><strong>Note:</strong> Methods that perform I/O operations
* require the {@link android.Manifest.permission#NFC} permission.
*/
public final class IsoDep extends BasicTagTechnology {
private static final String TAG = "NFC";
/** @hide */
public static final String EXTRA_HI_LAYER_RESP = "hiresp";
/** @hide */
public static final String EXTRA_HIST_BYTES = "histbytes";
private byte[] mHiLayerResponse = null;
private byte[] mHistBytes = null;
/**
* Get an instance of {@link IsoDep} for the given tag.
* <p>Does not cause any RF activity and does not block.
* <p>Returns null if {@link IsoDep} was not enumerated in {@link Tag#getTechList}.
* This indicates the tag does not support ISO-DEP.
*
* @param tag an ISO-DEP compatible tag
* @return ISO-DEP object
*/
public static IsoDep get(Tag tag) {
if (!tag.hasTech(TagTechnology.ISO_DEP)) return null;
try {
return new IsoDep(tag);
} catch (RemoteException e) {
return null;
}
}
/** @hide */
public IsoDep(Tag tag)
throws RemoteException {
super(tag, TagTechnology.ISO_DEP);
Bundle extras = tag.getTechExtras(TagTechnology.ISO_DEP);
if (extras != null) {
mHiLayerResponse = extras.getByteArray(EXTRA_HI_LAYER_RESP);
mHistBytes = extras.getByteArray(EXTRA_HIST_BYTES);
}
}
/**
* Set the timeout of {@link #transceive} in milliseconds.
* <p>The timeout only applies to ISO-DEP {@link #transceive}, 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.ISO_DEP, 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 timeout for {@link #transceive} 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.ISO_DEP);
} catch (RemoteException e) {
Log.e(TAG, "NFC service dead", e);
return 0;
}
}
/**
* Return the ISO-DEP historical bytes for {@link NfcA} tags.
* <p>Does not cause any RF activity and does not block.
* <p>The historical bytes can be used to help identify a tag. They are present
* only on {@link IsoDep} tags that are based on {@link NfcA} RF technology.
* If this tag is not {@link NfcA} then null is returned.
* <p>In ISO 14443-4 terminology, the historical bytes are a subset of the RATS
* response.
*
* @return ISO-DEP historical bytes, or null if this is not a {@link NfcA} tag
*/
public byte[] getHistoricalBytes() {
return mHistBytes;
}
/**
* Return the higher layer response bytes for {@link NfcB} tags.
* <p>Does not cause any RF activity and does not block.
* <p>The higher layer response bytes can be used to help identify a tag.
* They are present only on {@link IsoDep} tags that are based on {@link NfcB}
* RF technology. If this tag is not {@link NfcB} then null is returned.
* <p>In ISO 14443-4 terminology, the higher layer bytes are a subset of the
* ATTRIB response.
*
* @return ISO-DEP historical bytes, or null if this is not a {@link NfcB} tag
*/
public byte[] getHiLayerResponse() {
return mHiLayerResponse;
}
/**
* Send raw ISO-DEP data to the tag and receive the response.
*
* <p>Applications must only send the INF payload, and not the start of frame and
* end of frame indicators. Applications do not need to fragment the payload, it
* will be automatically fragmented and defragmented by {@link #transceive} if
* it exceeds FSD/FSC limits.
*
* <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.
*
* @param data command bytes to send, must not be null
* @return response bytes received, will not be null
* @throws TagLostException if the tag leaves the field
* @throws IOException if there is an I/O failure, or this operation is canceled
*/
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();
}
/**
* <p>Standard APDUs have a 1-byte length field, allowing a maximum of
* 255 payload bytes, which results in a maximum APDU length of 261 bytes.
*
* <p>Extended length APDUs have a 3-byte length field, allowing 65535
* payload bytes.
*
* <p>Some NFC adapters, like the one used in the Nexus S and the Galaxy Nexus
* do not support extended length APDUs. They are expected to be well-supported
* in the future though. Use this method to check for extended length APDU
* support.
*
* @return whether the NFC adapter on this device supports extended length APDUs.
*/
public boolean isExtendedLengthApduSupported() {
try {
return mTag.getTagService().getExtendedLengthApdusSupported();
} catch (RemoteException e) {
Log.e(TAG, "NFC service dead", e);
return false;
}
}
}
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