Add test to check socket close state after vpn connects

Bug: 270298713
Test: atest com.android.cts.net.HostsideVpnTests
Change-Id: Id090eea877de1c8fb6d195429b7affdbfc2abb6a
diff --git a/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java b/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java
index b6902b5..c28ee64 100755
--- a/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java
+++ b/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java
@@ -1274,6 +1274,31 @@
     }
 
     @Test
+    public void testSocketClosed() throws Exception {
+        assumeTrue(supportedHardware());
+
+        final FileDescriptor localFd = openSocketFd(TEST_HOST, 80, TIMEOUT_MS);
+        final List<FileDescriptor> remoteFds = new ArrayList<>();
+
+        for (int i = 0; i < 30; i++) {
+            remoteFds.add(openSocketFdInOtherApp(TEST_HOST, 80, TIMEOUT_MS));
+        }
+
+        final String allowedApps = mRemoteSocketFactoryClient.getPackageName() + "," + mPackageName;
+        startVpn(new String[] {"192.0.2.2/32", "2001:db8:1:2::ffe/128"},
+                new String[] {"192.0.2.0/24", "2001:db8::/32"},
+                allowedApps, "", null, null /* underlyingNetworks */, false /* isAlwaysMetered */);
+
+        // Socket owned by VPN uid is not closed
+        assertSocketStillOpen(localFd, TEST_HOST);
+
+        // Sockets not owned by VPN uid are closed
+        for (final FileDescriptor remoteFd: remoteFds) {
+            assertSocketClosed(remoteFd, TEST_HOST);
+        }
+    }
+
+    @Test
     public void testExcludedRoutes() throws Exception {
         assumeTrue(supportedHardware());
         assumeTrue(SdkLevel.isAtLeastT());
diff --git a/tests/cts/hostside/src/com/android/cts/net/HostsideVpnTests.java b/tests/cts/hostside/src/com/android/cts/net/HostsideVpnTests.java
index 603779d..3ca4775 100644
--- a/tests/cts/hostside/src/com/android/cts/net/HostsideVpnTests.java
+++ b/tests/cts/hostside/src/com/android/cts/net/HostsideVpnTests.java
@@ -51,6 +51,10 @@
         runDeviceTests(TEST_PKG, TEST_PKG + ".VpnTest", "testAppDisallowed");
     }
 
+    public void testSocketClosed() throws Exception {
+        runDeviceTests(TEST_PKG, TEST_PKG + ".VpnTest", "testSocketClosed");
+    }
+
     public void testGetConnectionOwnerUidSecurity() throws Exception {
         runDeviceTests(TEST_PKG, TEST_PKG + ".VpnTest", "testGetConnectionOwnerUidSecurity");
     }