Support QosCallback for UDP socket : validate

Do validate() before sending QosCallback to App.
If validate fails, notify error to App & tear down QosCallback internally.

Bug: 203146631
Test: atest & verified on LTE test equipment
Change-Id: I05e28b10b816381a191272c85b3b178204d835d7
diff --git a/service/src/com/android/server/connectivity/QosCallbackAgentConnection.java b/service/src/com/android/server/connectivity/QosCallbackAgentConnection.java
index 534dbe7..e682026 100644
--- a/service/src/com/android/server/connectivity/QosCallbackAgentConnection.java
+++ b/service/src/com/android/server/connectivity/QosCallbackAgentConnection.java
@@ -30,6 +30,8 @@
 import android.telephony.data.NrQosSessionAttributes;
 import android.util.Log;
 
+import com.android.modules.utils.build.SdkLevel;
+
 import java.util.Objects;
 
 /**
@@ -149,6 +151,7 @@
 
     void sendEventEpsQosSessionAvailable(final QosSession session,
             final EpsBearerQosSessionAttributes attributes) {
+        if (!validateOrSendErrorAndUnregister()) return;
         try {
             if (DBG) log("sendEventEpsQosSessionAvailable: sending...");
             mCallback.onQosEpsBearerSessionAvailable(session, attributes);
@@ -159,6 +162,7 @@
 
     void sendEventNrQosSessionAvailable(final QosSession session,
             final NrQosSessionAttributes attributes) {
+        if (!validateOrSendErrorAndUnregister()) return;
         try {
             if (DBG) log("sendEventNrQosSessionAvailable: sending...");
             mCallback.onNrQosSessionAvailable(session, attributes);
@@ -168,6 +172,7 @@
     }
 
     void sendEventQosSessionLost(@NonNull final QosSession session) {
+        if (!validateOrSendErrorAndUnregister()) return;
         try {
             if (DBG) log("sendEventQosSessionLost: sending...");
             mCallback.onQosSessionLost(session);
@@ -185,6 +190,21 @@
         }
     }
 
+    private boolean validateOrSendErrorAndUnregister() {
+        final int exceptionType = mFilter.validate();
+        if (exceptionType != EX_TYPE_FILTER_NONE) {
+             log("validation fail before sending QosCallback.");
+             // Error callback is returned from Android T to prevent any disruption of application
+             // running on Android S.
+             if (SdkLevel.isAtLeastT()) {
+                sendEventQosCallbackError(exceptionType);
+                mQosCallbackTracker.unregisterCallback(mCallback);
+            }
+            return false;
+        }
+        return true;
+    }
+
     private static void log(@NonNull final String msg) {
         Log.d(TAG, msg);
     }