Dropping NAT-T keepalive packet from APF

Add NAT Traversal keepalive filter to APF program to
drop NAT-T keepalive packets when NAT-T keepalive
offload is starting.

Bug: 33530442
Test: - atest NetworkStackTests
      - atest FrameworksNetTests

Change-Id: If62ba7fdb5f0f0f0a7a59ec169e82b4e3147eedd
Merged-In: If62ba7fdb5f0f0f0a7a59ec169e82b4e3147eedd
Merged-In: Ib3416ec37f0de12daf882068e00673ad60438c1a
(cherry picked from commit 95538d2d6b13188c9a742000a85517aef28bb833)

1 files changed, 11 insertions, 0 deletions

diff --git a/src/android/net/util/NetworkStackUtils.java b/src/android/net/util/NetworkStackUtils.java
index 2934e1c..9bf1b96 100644
--- a/src/android/net/util/NetworkStackUtils.java
+++ b/src/android/net/util/NetworkStackUtils.java
@@ -24,6 +24,8 @@ import android.util.SparseArray;
 import java.io.FileDescriptor;
 import java.io.IOException;
 import java.net.Inet4Address;
+import java.net.Inet6Address;
+import java.net.InetAddress;
 import java.net.SocketException;
 import java.util.List;
 import java.util.function.Predicate;
@@ -228,4 +230,13 @@ public class NetworkStackUtils {
 
     private static native void addArpEntry(byte[] ethAddr, byte[] netAddr, String ifname,
             FileDescriptor fd) throws IOException;
+
+    /**
+     * Return IP address and port in a string format.
+     */
+    public static String addressAndPortToString(InetAddress address, int port) {
+        return String.format(
+                (address instanceof Inet6Address) ? "[%s]:%d" : "%s:%d",
+                        address.getHostAddress(), port);
+    }
 }