Force creation of Socket upon Transform application

This change forces Socket and DatagramSocket to populate the
SocketImpl, ensuring that the socket file descriptor can be
retrieved when applying Transport mode Transforms

This is done by calling getSoLinger(), triggering a getImpl(), which
triggers setImpl() if needed.

Bug: 77491294
Test: Added tests in IpSecManagerTest, ran on walleye
Change-Id: I40da08b031357710eb794e0f866aec5660c79594

tests/net/java/android/net/IpSecManagerTest.java

@@ -37,6 +37,7 @@ import android.system.Os;
 import com.android.server.IpSecService;
 
 import java.net.InetAddress;
+import java.net.Socket;
 import java.net.UnknownHostException;
 
 import org.junit.Before;
@@ -187,6 +188,33 @@ public class IpSecManagerTest {
         verify(mMockIpSecService).closeUdpEncapsulationSocket(DUMMY_RESOURCE_ID);
     }
 
+    @Test
+    public void testApplyTransportModeTransformEnsuresSocketCreation() throws Exception {
+        Socket socket = new Socket();
+        IpSecConfig dummyConfig = new IpSecConfig();
+        IpSecTransform dummyTransform = new IpSecTransform(null, dummyConfig);
+
+        // Even if underlying SocketImpl is not initalized, this should force the init, and
+        // thereby succeed.
+        mIpSecManager.applyTransportModeTransform(
+                socket, IpSecManager.DIRECTION_IN, dummyTransform);
+
+        // Check to make sure the FileDescriptor is non-null
+        assertNotNull(socket.getFileDescriptor$());
+    }
+
+    @Test
+    public void testRemoveTransportModeTransformsForcesSocketCreation() throws Exception {
+        Socket socket = new Socket();
+
+        // Even if underlying SocketImpl is not initalized, this should force the init, and
+        // thereby succeed.
+        mIpSecManager.removeTransportModeTransforms(socket);
+
+        // Check to make sure the FileDescriptor is non-null
+        assertNotNull(socket.getFileDescriptor$());
+    }
+
     @Test
     public void testOpenEncapsulationSocketOnRandomPort() throws Exception {
         IpSecUdpEncapResponse udpEncapResp =