[KA02] internal cleanup and refactor for SocketKeepalive

In previous change, the new SocketKeepalive API was exported.
But internally, old PacketKeepalive names and structures are
still used.

This change rename them properly for code consistency and also
refactor KeepalivePacketData to support different types of
KeepalivePacketData.

(clean cherry-pick from aosp/860394)

Bug: 114151147
Test: 1. atest FrameworksNetTests
      2. atest FrameworksWifiTests
      3. atest FrameworksTelephonyTests

Change-Id: Ia9917d12987e91e87e34ffb3f126e7bc7c9c187e
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index f807543..1cb2c4a 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -60,7 +60,6 @@
 import android.database.ContentObserver;
 import android.net.ConnectionInfo;
 import android.net.ConnectivityManager;
-import android.net.ConnectivityManager.PacketKeepalive;
 import android.net.IConnectivityManager;
 import android.net.IIpConnectivityMetrics;
 import android.net.INetd;
@@ -94,6 +93,7 @@
 import android.net.PrivateDnsConfigParcel;
 import android.net.ProxyInfo;
 import android.net.RouteInfo;
+import android.net.SocketKeepalive;
 import android.net.UidRange;
 import android.net.Uri;
 import android.net.VpnService;
@@ -2488,8 +2488,8 @@
                     nai.networkMisc.acceptUnvalidated = msg.arg1 == 1;
                     break;
                 }
-                case NetworkAgent.EVENT_PACKET_KEEPALIVE: {
-                    mKeepaliveTracker.handleEventPacketKeepalive(nai, msg);
+                case NetworkAgent.EVENT_SOCKET_KEEPALIVE: {
+                    mKeepaliveTracker.handleEventSocketKeepalive(nai, msg);
                     break;
                 }
             }
@@ -2863,8 +2863,7 @@
         // sending all CALLBACK_LOST messages (for requests, not listens) at the end
         // of rematchAllNetworksAndRequests
         notifyNetworkCallbacks(nai, ConnectivityManager.CALLBACK_LOST);
-        mKeepaliveTracker.handleStopAllKeepalives(nai,
-                ConnectivityManager.PacketKeepalive.ERROR_INVALID_NETWORK);
+        mKeepaliveTracker.handleStopAllKeepalives(nai, SocketKeepalive.ERROR_INVALID_NETWORK);
         for (String iface : nai.linkProperties.getAllInterfaceNames()) {
             // Disable wakeup packet monitoring for each interface.
             wakeupModifyInterface(iface, nai.networkCapabilities, false);
@@ -3456,12 +3455,12 @@
                     break;
                 }
                 // Sent by KeepaliveTracker to process an app request on the state machine thread.
-                case NetworkAgent.CMD_START_PACKET_KEEPALIVE: {
+                case NetworkAgent.CMD_START_SOCKET_KEEPALIVE: {
                     mKeepaliveTracker.handleStartKeepalive(msg);
                     break;
                 }
                 // Sent by KeepaliveTracker to process an app request on the state machine thread.
-                case NetworkAgent.CMD_STOP_PACKET_KEEPALIVE: {
+                case NetworkAgent.CMD_STOP_SOCKET_KEEPALIVE: {
                     NetworkAgentInfo nai = getNetworkAgentInfoForNetwork((Network) msg.obj);
                     int slot = msg.arg1;
                     int reason = msg.arg2;
@@ -6363,7 +6362,7 @@
         mKeepaliveTracker.startNattKeepalive(
                 getNetworkAgentInfoForNetwork(network),
                 intervalSeconds, messenger, binder,
-                srcAddr, srcPort, dstAddr, ConnectivityManager.PacketKeepalive.NATT_PORT);
+                srcAddr, srcPort, dstAddr, NattSocketKeepalive.NATT_PORT);
     }
 
     @Override
@@ -6380,7 +6379,7 @@
     @Override
     public void stopKeepalive(Network network, int slot) {
         mHandler.sendMessage(mHandler.obtainMessage(
-                NetworkAgent.CMD_STOP_PACKET_KEEPALIVE, slot, PacketKeepalive.SUCCESS, network));
+                NetworkAgent.CMD_STOP_SOCKET_KEEPALIVE, slot, SocketKeepalive.SUCCESS, network));
     }
 
     @Override