commit df347448a102a996c3eef12d6a9a0319051e2f5f
author chiachangwang <chiachangwang@google.com> Tue Jun 06 03:12:24 2023 +0000
committer Chiachang Wang <chiachangwang@google.com> Wed Jun 07 02:05:10 2023 +0000
tree f48cc25de1fffe600475ba2c032c23e2f2413010
parent f2b38772ac999b3e218014478f9f496969193850

Make a v4 nattKeepalivePacket helper method

This is a preparation change for the subsequent changes to
separate the logic for constructing a v4 NAT-T keepalive
packets to a dedicated method.

Bug: 196453719
Test: atest FrameworksNetTests
Change-Id: If72b4875e65a547bbf90367eacce7b145358006a

framework/src/android/net/NattKeepalivePacketData.java

diff --git a/framework/src/android/net/NattKeepalivePacketData.java b/framework/src/android/net/NattKeepalivePacketData.java
index c4f8fc2..d76f569 100644
--- a/framework/src/android/net/NattKeepalivePacketData.java
+++ b/framework/src/android/net/NattKeepalivePacketData.java
@@ -55,15 +55,22 @@
     public static NattKeepalivePacketData nattKeepalivePacket(
             InetAddress srcAddress, int srcPort, InetAddress dstAddress, int dstPort)
             throws InvalidPacketException {
+        if (dstPort != NattSocketKeepalive.NATT_PORT) {
+            throw new InvalidPacketException(ERROR_INVALID_PORT);
+        }
 
         if (!(srcAddress instanceof Inet4Address) || !(dstAddress instanceof Inet4Address)) {
             throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS);
         }
 
-        if (dstPort != NattSocketKeepalive.NATT_PORT) {
-            throw new InvalidPacketException(ERROR_INVALID_PORT);
-        }
+        return nattKeepalivePacketv4(
+                (Inet4Address) srcAddress, srcPort,
+                (Inet4Address) dstAddress, dstPort);
+    }
 
+    private static NattKeepalivePacketData nattKeepalivePacketv4(
+            Inet4Address srcAddress, int srcPort, Inet4Address dstAddress, int dstPort)
+            throws InvalidPacketException {
         int length = IPV4_HEADER_LENGTH + UDP_HEADER_LENGTH + 1;
         ByteBuffer buf = ByteBuffer.allocate(length);
         buf.order(ByteOrder.BIG_ENDIAN);