Implementing support for NFC observe mode, polling loop fingerprints

and field strength along with their associated APIs.

Bug: 294217286
Bug: 294435374
Bug: 296057223
Test: tested with CTS and manually
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:81080d559182483d9582dc8dc9ed75de3307c572)
Merged-In: I884527f9271a93997fa47b3764f9fa711cddb6f2

Change-Id: I884527f9271a93997fa47b3764f9fa711cddb6f2

9 files changed, 255 insertions, 0 deletions

diff --git a/AconfigFlags.bp b/AconfigFlags.bp
index 45f65709533f..e0745faecf5a 100644
--- a/AconfigFlags.bp
+++ b/AconfigFlags.bp
@@ -121,6 +121,18 @@ aconfig_declarations {
     srcs: ["core/java/android/nfc/*.aconfig"],
 }
 
+cc_aconfig_library {
+    name: "android_nfc_flags_aconfig_c_lib",
+    vendor_available: true,
+    aconfig_declarations: "android.nfc.flags-aconfig",
+    apex_available: [
+        "//apex_available:platform",
+        "com.android.nfcservices",
+        "nfc_nci.st21nfc.default",
+    ],
+    defaults: ["framework-minus-apex-aconfig-java-defaults"],
+}
+
 java_aconfig_library {
     name: "android.nfc.flags-aconfig-java",
     aconfig_declarations: "android.nfc.flags-aconfig",
diff --git a/core/api/current.txt b/core/api/current.txt
index c9cba0065dee..e392bd3d2c11 100644
--- a/core/api/current.txt
+++ b/core/api/current.txt
@@ -29105,14 +29105,17 @@ package android.nfc {
   }
 
   public final class NfcAdapter {
+    method @FlaggedApi("android.nfc.nfc_observe_mode") public boolean allowTransaction();
     method public void disableForegroundDispatch(android.app.Activity);
     method public void disableReaderMode(android.app.Activity);
+    method @FlaggedApi("android.nfc.nfc_observe_mode") public boolean disallowTransaction();
     method public void enableForegroundDispatch(android.app.Activity, android.app.PendingIntent, android.content.IntentFilter[], String[][]);
     method public void enableReaderMode(android.app.Activity, android.nfc.NfcAdapter.ReaderCallback, int, android.os.Bundle);
     method public static android.nfc.NfcAdapter getDefaultAdapter(android.content.Context);
     method @Nullable public android.nfc.NfcAntennaInfo getNfcAntennaInfo();
     method public boolean ignore(android.nfc.Tag, int, android.nfc.NfcAdapter.OnTagRemovedListener, android.os.Handler);
     method public boolean isEnabled();
+    method @FlaggedApi("android.nfc.nfc_observe_mode") public boolean isObserveModeSupported();
     method @FlaggedApi("android.nfc.enable_nfc_reader_option") public boolean isReaderOptionEnabled();
     method @FlaggedApi("android.nfc.enable_nfc_reader_option") public boolean isReaderOptionSupported();
     method public boolean isSecureNfcEnabled();
@@ -29220,6 +29223,7 @@ package android.nfc.cardemulation {
     method public boolean removeAidsForService(android.content.ComponentName, String);
     method @NonNull @RequiresPermission(android.Manifest.permission.NFC) public boolean setOffHostForService(@NonNull android.content.ComponentName, @NonNull String);
     method public boolean setPreferredService(android.app.Activity, android.content.ComponentName);
+    method @FlaggedApi("android.nfc.nfc_observe_mode") public boolean setServiceObserveModeDefault(@NonNull android.content.ComponentName, boolean);
     method public boolean supportsAidPrefixRegistration();
     method @NonNull @RequiresPermission(android.Manifest.permission.NFC) public boolean unsetOffHostForService(@NonNull android.content.ComponentName);
     method public boolean unsetPreferredService(android.app.Activity);
@@ -29239,9 +29243,20 @@ package android.nfc.cardemulation {
     method public final android.os.IBinder onBind(android.content.Intent);
     method public abstract void onDeactivated(int);
     method public abstract byte[] processCommandApdu(byte[], android.os.Bundle);
+    method @FlaggedApi("android.nfc.nfc_read_polling_loop") public void processPollingFrames(@NonNull java.util.List<android.os.Bundle>);
     method public final void sendResponseApdu(byte[]);
     field public static final int DEACTIVATION_DESELECTED = 1; // 0x1
     field public static final int DEACTIVATION_LINK_LOSS = 0; // 0x0
+    field @FlaggedApi("android.nfc.nfc_read_polling_loop") public static final String POLLING_LOOP_DATA_KEY = "android.nfc.cardemulation.DATA";
+    field @FlaggedApi("android.nfc.nfc_read_polling_loop") public static final String POLLING_LOOP_GAIN_KEY = "android.nfc.cardemulation.GAIN";
+    field @FlaggedApi("android.nfc.nfc_read_polling_loop") public static final String POLLING_LOOP_TIMESTAMP_KEY = "android.nfc.cardemulation.TIMESTAMP";
+    field @FlaggedApi("android.nfc.nfc_read_polling_loop") public static final char POLLING_LOOP_TYPE_A = 65; // 0x0041 'A'
+    field @FlaggedApi("android.nfc.nfc_read_polling_loop") public static final char POLLING_LOOP_TYPE_B = 66; // 0x0042 'B'
+    field @FlaggedApi("android.nfc.nfc_read_polling_loop") public static final char POLLING_LOOP_TYPE_F = 70; // 0x0046 'F'
+    field @FlaggedApi("android.nfc.nfc_read_polling_loop") public static final String POLLING_LOOP_TYPE_KEY = "android.nfc.cardemulation.TYPE";
+    field @FlaggedApi("android.nfc.nfc_read_polling_loop") public static final char POLLING_LOOP_TYPE_OFF = 88; // 0x0058 'X'
+    field @FlaggedApi("android.nfc.nfc_read_polling_loop") public static final char POLLING_LOOP_TYPE_ON = 79; // 0x004f 'O'
+    field @FlaggedApi("android.nfc.nfc_read_polling_loop") public static final char POLLING_LOOP_TYPE_UNKNOWN = 85; // 0x0055 'U'
     field public static final String SERVICE_INTERFACE = "android.nfc.cardemulation.action.HOST_APDU_SERVICE";
     field public static final String SERVICE_META_DATA = "android.nfc.cardemulation.host_apdu_service";
   }
diff --git a/core/java/android/nfc/INfcAdapter.aidl b/core/java/android/nfc/INfcAdapter.aidl
index 0c95c2ec7a7a..f6beec179d57 100644
--- a/core/java/android/nfc/INfcAdapter.aidl
+++ b/core/java/android/nfc/INfcAdapter.aidl
@@ -84,4 +84,6 @@ interface INfcAdapter
     boolean isReaderOptionSupported();
     @JavaPassthrough(annotation="@android.annotation.RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)")
     boolean enableReaderOption(boolean enable);
+    boolean isObserveModeSupported();
+    boolean setObserveMode(boolean enabled);
 }
diff --git a/core/java/android/nfc/INfcCardEmulation.aidl b/core/java/android/nfc/INfcCardEmulation.aidl
index c7b3b2c03f65..191385a3c13d 100644
--- a/core/java/android/nfc/INfcCardEmulation.aidl
+++ b/core/java/android/nfc/INfcCardEmulation.aidl
@@ -30,6 +30,7 @@ interface INfcCardEmulation
     boolean isDefaultServiceForAid(int userHandle, in ComponentName service, String aid);
     boolean setDefaultServiceForCategory(int userHandle, in ComponentName service, String category);
     boolean setDefaultForNextTap(int userHandle, in ComponentName service);
+    boolean setServiceObserveModeDefault(int userId, in android.content.ComponentName service, boolean enable);
     boolean registerAidGroupForService(int userHandle, in ComponentName service, in AidGroup aidGroup);
     boolean setOffHostForService(int userHandle, in ComponentName service, in String offHostSecureElement);
     boolean unsetOffHostForService(int userHandle, in ComponentName service);
diff --git a/core/java/android/nfc/NfcAdapter.java b/core/java/android/nfc/NfcAdapter.java
index c89759553810..98a980f5e7f8 100644
--- a/core/java/android/nfc/NfcAdapter.java
+++ b/core/java/android/nfc/NfcAdapter.java
@@ -1081,6 +1081,61 @@ public final class NfcAdapter {
         }
     }
 
+
+    /**
+     * Returns whether the device supports observer mode or not. When observe
+     * mode is enabled, the NFC hardware will listen for NFC readers, but not
+     * respond to them. When observe mode is disabled, the NFC hardware will
+     * resoond to the reader and proceed with the transaction.
+     * @return true if the mode is supported, false otherwise.
+     */
+    @FlaggedApi(Flags.FLAG_NFC_OBSERVE_MODE)
+    public boolean isObserveModeSupported() {
+        try {
+            return sService.isObserveModeSupported();
+        } catch (RemoteException e) {
+            attemptDeadServiceRecovery(e);
+            return false;
+        }
+    }
+
+   /**
+    * Disables observe mode to allow the transaction to proceed. See
+    * {@link #isObserveModeSupported()} for a description of observe mode and
+    * use {@link #disallowTransaction()} to enable observe mode and block
+    * transactions again.
+    *
+    * @return boolean indicating success or failure.
+    */
+    @FlaggedApi(Flags.FLAG_NFC_OBSERVE_MODE)
+    public boolean allowTransaction() {
+        try {
+            return sService.setObserveMode(false);
+        } catch (RemoteException e) {
+            attemptDeadServiceRecovery(e);
+            return false;
+        }
+    }
+
+    /**
+    * Signals that the transaction has completed and observe mode may be
+    * reenabled. See {@link #isObserveModeSupported()} for a description of
+    * observe mode and use {@link #allowTransaction()} to disable observe
+    * mode and allow transactions to proceed.
+    *
+    * @return boolean indicating success or failure.
+    */
+
+    @FlaggedApi(Flags.FLAG_NFC_OBSERVE_MODE)
+    public boolean disallowTransaction() {
+        try {
+            return sService.setObserveMode(true);
+        } catch (RemoteException e) {
+            attemptDeadServiceRecovery(e);
+            return false;
+        }
+    }
+
     /**
      * Resumes default polling for the current device state if polling is paused. Calling
      * this while polling is not paused is a no-op.
diff --git a/core/java/android/nfc/cardemulation/CardEmulation.java b/core/java/android/nfc/cardemulation/CardEmulation.java
index d048b595ad1e..58b6179691e9 100644
--- a/core/java/android/nfc/cardemulation/CardEmulation.java
+++ b/core/java/android/nfc/cardemulation/CardEmulation.java
@@ -328,6 +328,24 @@ public final class CardEmulation {
             return SELECTION_MODE_ASK_IF_CONFLICT;
         }
     }
+    /**
+     * Sets whether the system should default to observe mode or not when
+     * the service is in the foreground or the default payment service.
+     *
+     * @param service The component name of the service
+     * @param enable Whether the servic should default to observe mode or not
+     * @return whether the change was successful.
+     */
+    @FlaggedApi(Flags.FLAG_NFC_OBSERVE_MODE)
+    public boolean setServiceObserveModeDefault(@NonNull ComponentName service, boolean enable) {
+        try {
+            return sService.setServiceObserveModeDefault(mContext.getUser().getIdentifier(),
+                    service, enable);
+        } catch (RemoteException e) {
+            Log.e(TAG, "Failed to reach CardEmulationService.");
+        }
+        return  false;
+    }
 
     /**
      * Registers a list of AIDs for a specific category for the
diff --git a/core/java/android/nfc/cardemulation/HostApduService.java b/core/java/android/nfc/cardemulation/HostApduService.java
index 55d0e73780a2..7cd2533a7dbf 100644
--- a/core/java/android/nfc/cardemulation/HostApduService.java
+++ b/core/java/android/nfc/cardemulation/HostApduService.java
@@ -16,11 +16,14 @@
 
 package android.nfc.cardemulation;
 
+import android.annotation.FlaggedApi;
+import android.annotation.NonNull;
 import android.annotation.SdkConstant;
 import android.annotation.SdkConstant.SdkConstantType;
 import android.app.Service;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.nfc.NfcAdapter;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.IBinder;
@@ -29,6 +32,9 @@ import android.os.Messenger;
 import android.os.RemoteException;
 import android.util.Log;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * <p>HostApduService is a convenience {@link Service} class that can be
  * extended to emulate an NFC card inside an Android
@@ -230,9 +236,99 @@ public abstract class HostApduService extends Service {
     /**
      * @hide
      */
+    public static final int MSG_POLLING_LOOP = 4;
+
+    /**
+     * @hide
+     */
     public static final String KEY_DATA = "data";
 
     /**
+     * POLLING_LOOP_TYPE_KEY is the Bundle key for the type of
+     * polling loop frame in the Bundle passed to {@link #processPollingFrames(List)}
+     */
+    @FlaggedApi(android.nfc.Flags.FLAG_NFC_READ_POLLING_LOOP)
+    public static final String POLLING_LOOP_TYPE_KEY = "android.nfc.cardemulation.TYPE";
+
+    /**
+     * POLLING_LOOP_TYPE_A is the value associated with the key
+     * POLLING_LOOP_TYPE  in the Bundle passed to {@link #processPollingFrames(List)}
+     * when the polling loop is for NFC-A.
+     */
+    @FlaggedApi(android.nfc.Flags.FLAG_NFC_READ_POLLING_LOOP)
+    public static final char POLLING_LOOP_TYPE_A = 'A';
+
+    /**
+     * POLLING_LOOP_TYPE_B is the value associated with the key
+     * POLLING_LOOP_TYPE  in the Bundle passed to {@link #processPollingFrames(List)}
+     * when the polling loop is for NFC-B.
+     */
+    @FlaggedApi(android.nfc.Flags.FLAG_NFC_READ_POLLING_LOOP)
+    public static final char POLLING_LOOP_TYPE_B = 'B';
+
+    /**
+     * POLLING_LOOP_TYPE_F is the value associated with the key
+     * POLLING_LOOP_TYPE  in the Bundle passed to {@link #processPollingFrames(List)}
+     * when the polling loop is for NFC-F.
+     */
+    @FlaggedApi(android.nfc.Flags.FLAG_NFC_READ_POLLING_LOOP)
+    public static final char POLLING_LOOP_TYPE_F = 'F';
+
+    /**
+     * POLLING_LOOP_TYPE_ON is the value associated with the key
+     * POLLING_LOOP_TYPE  in the Bundle passed to {@link #processPollingFrames(List)}
+     * when the polling loop turns on.
+     */
+    @FlaggedApi(android.nfc.Flags.FLAG_NFC_READ_POLLING_LOOP)
+    public static final char POLLING_LOOP_TYPE_ON = 'O';
+
+    /**
+     * POLLING_LOOP_TYPE_OFF is the value associated with the key
+     * POLLING_LOOP_TYPE  in the Bundle passed to {@link #processPollingFrames(List)}
+     * when the polling loop turns off.
+     */
+    @FlaggedApi(android.nfc.Flags.FLAG_NFC_READ_POLLING_LOOP)
+    public static final char POLLING_LOOP_TYPE_OFF = 'X';
+
+    /**
+     * POLLING_LOOP_TYPE_UNKNOWN is the value associated with the key
+     * POLLING_LOOP_TYPE  in the Bundle passed to {@link #processPollingFrames(List)}
+     * when the polling loop frame isn't recognized.
+     */
+    @FlaggedApi(android.nfc.Flags.FLAG_NFC_READ_POLLING_LOOP)
+    public static final char POLLING_LOOP_TYPE_UNKNOWN = 'U';
+
+    /**
+     * POLLING_LOOP_DATA is the Bundle key for the raw data of captured from
+     * the polling loop frame in the Bundle passed to {@link #processPollingFrames(List)}
+     * when the frame type isn't recognized.
+     */
+    @FlaggedApi(android.nfc.Flags.FLAG_NFC_READ_POLLING_LOOP)
+    public static final String POLLING_LOOP_DATA_KEY = "android.nfc.cardemulation.DATA";
+
+    /**
+     * POLLING_LOOP_GAIN_KEY is the Bundle key for the field strength of
+     * the polling loop frame in the Bundle passed to {@link #processPollingFrames(List)}
+     * when the frame type isn't recognized.
+     */
+    @FlaggedApi(android.nfc.Flags.FLAG_NFC_READ_POLLING_LOOP)
+    public static final String POLLING_LOOP_GAIN_KEY = "android.nfc.cardemulation.GAIN";
+
+    /**
+     * POLLING_LOOP_TIMESTAMP_KEY is the Bundle key for the timestamp of
+     * the polling loop frame in the Bundle passed to {@link #processPollingFrames(List)}
+     * when the frame type isn't recognized.
+     */
+    @FlaggedApi(android.nfc.Flags.FLAG_NFC_READ_POLLING_LOOP)
+    public static final String POLLING_LOOP_TIMESTAMP_KEY = "android.nfc.cardemulation.TIMESTAMP";
+
+    /**
+     * @hide
+     */
+    public static final String POLLING_LOOP_FRAMES_BUNDLE_KEY =
+            "android.nfc.cardemulation.POLLING_FRAMES";
+
+    /**
      * Messenger interface to NfcService for sending responses.
      * Only accessed on main thread by the message handler.
      *
@@ -255,6 +351,7 @@ public abstract class HostApduService extends Service {
 
                 byte[] apdu = dataBundle.getByteArray(KEY_DATA);
                 if (apdu != null) {
+                        HostApduService has = HostApduService.this;
                     byte[] responseApdu = processCommandApdu(apdu, null);
                     if (responseApdu != null) {
                         if (mNfcService == null) {
@@ -306,6 +403,12 @@ public abstract class HostApduService extends Service {
                     Log.e(TAG, "RemoteException calling into NfcService.");
                 }
                 break;
+                case MSG_POLLING_LOOP:
+                    ArrayList<Bundle> frames =
+                            msg.getData().getParcelableArrayList(POLLING_LOOP_FRAMES_BUNDLE_KEY,
+                            Bundle.class);
+                    processPollingFrames(frames);
+                    break;
             default:
                 super.handleMessage(msg);
             }
@@ -366,6 +469,21 @@ public abstract class HostApduService extends Service {
         }
     }
 
+    /**
+     * This method is called when a polling frame has been received from a
+     * remote device. If the device is in observe mode, the service should
+     * call {@link NfcAdapter#allowTransaction()} once it is ready to proceed
+     * with the transaction. If the device is not in observe mode, the service
+     * can use this polling frame information to determine how to proceed if it
+     * subsequently has {@link #processCommandApdu(byte[], Bundle)} called. The
+     * service must override this method inorder to receive polling frames,
+     * otherwise the base implementation drops the frame.
+     *
+     * @param frame A description of the polling frame.
+     */
+    @FlaggedApi(android.nfc.Flags.FLAG_NFC_READ_POLLING_LOOP)
+    public void processPollingFrames(@NonNull List<Bundle> frame) {
+    }
 
     /**
      * <p>This method will be called when a command APDU has been received
diff --git a/core/java/android/nfc/flags.aconfig b/core/java/android/nfc/flags.aconfig
index cd50ace036de..17e042761dbe 100644
--- a/core/java/android/nfc/flags.aconfig
+++ b/core/java/android/nfc/flags.aconfig
@@ -20,3 +20,31 @@ flag {
     description: "Flag for NFC user restriction"
     bug: "291187960"
 }
+
+flag {
+    name: "nfc_observe_mode"
+    namespace: "nfc"
+    description: "Enable NFC Observe Mode"
+    bug: "294217286"
+}
+
+flag {
+    name: "nfc_read_polling_loop"
+    namespace: "nfc"
+    description: "Enable NFC Polling Loop Notifications"
+    bug: "294217286"
+}
+
+flag {
+    name: "nfc_observe_mode_st_shim"
+    namespace: "nfc"
+    description: "Enable NFC Observe Mode ST shim"
+    bug: "294217286"
+}
+
+flag {
+    name: "nfc_read_polling_loop_st_shim"
+    namespace: "nfc"
+    description: "Enable NFC Polling Loop Notifications ST shim"
+    bug: "294217286"
+}
diff --git a/core/res/res/values/attrs.xml b/core/res/res/values/attrs.xml
index 6f7bc53e891c..3413282351ff 100644
--- a/core/res/res/values/attrs.xml
+++ b/core/res/res/values/attrs.xml
@@ -4303,6 +4303,9 @@
         <!-- Whether the device must be screen on before routing data to this service.
              The default is true.-->
         <attr name="requireDeviceScreenOn" format="boolean"/>
+        <!-- Whether the device should default to observe mode when this service is
+             default or in the foreground. -->
+        <attr name="defaultToObserveMode" format="boolean"/>
     </declare-styleable>
 
     <!-- Use <code>offhost-apdu-service</code> as the root tag of the XML resource that
@@ -4327,6 +4330,9 @@
         <!-- Whether the device must be screen on before routing data to this service.
              The default is false.-->
         <attr name="requireDeviceScreenOn"/>
+        <!-- Whether the device should default to observe mode when this service is
+             default or in the foreground. -->
+        <attr name="defaultToObserveMode"/>
     </declare-styleable>
 
     <!-- Specify one or more <code>aid-group</code> elements inside a