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: I1c537485e11b31e5a6e0d8b7b6a1f396f9441746

1 files changed, 11 insertions, 0 deletions

diff --git a/src/android/net/util/NetworkStackUtils.java b/src/android/net/util/NetworkStackUtils.java
index abfed3e..541f9d8 100644
--- a/src/android/net/util/NetworkStackUtils.java
+++ b/src/android/net/util/NetworkStackUtils.java
@@ -23,6 +23,8 @@ 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;
@@ -227,4 +229,13 @@ 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);
+    }
 }