[Thread] introduce TestTunNetworkUtils and use it in existing test cases

TestTunNetworkUtils is a centralized place to control the test TUN networks used by integration test. With this we can safely tear down all test networks in `teardown()` instead of tearing down the newly created network in `finally` clause.

Bug: 377640059
Change-Id: I57b34bb2644bd6a5bb73ed1573932f35de657c8f
diff --git a/thread/tests/integration/src/android/net/thread/BorderRoutingTest.java b/thread/tests/integration/src/android/net/thread/BorderRoutingTest.java
index ddbef47..aeeed65 100644
--- a/thread/tests/integration/src/android/net/thread/BorderRoutingTest.java
+++ b/thread/tests/integration/src/android/net/thread/BorderRoutingTest.java
@@ -58,6 +58,7 @@
 import android.net.thread.utils.InfraNetworkDevice;
 import android.net.thread.utils.IntegrationTestUtils;
 import android.net.thread.utils.OtDaemonController;
+import android.net.thread.utils.TestTunNetworkUtils;
 import android.net.thread.utils.ThreadFeatureCheckerRule;
 import android.net.thread.utils.ThreadFeatureCheckerRule.RequiresIpv6MulticastRouting;
 import android.net.thread.utils.ThreadFeatureCheckerRule.RequiresSimulationThreadDevice;
@@ -160,6 +161,7 @@
     @After
     public void tearDown() throws Exception {
         mController.setTestNetworkAsUpstreamAndWait(null);
+        TestTunNetworkUtils.tearDownAllInfraNetworks();
 
         mHandlerThread.quitSafely();
         mHandlerThread.join();
@@ -226,19 +228,13 @@
         FullThreadDevice ftd = mFtds.get(0);
         joinNetworkAndWaitForOmr(ftd, DEFAULT_DATASET);
         Inet6Address ftdOmr = ftd.getOmrAddress();
-        // Create a new infra network and let Thread prefer it
-        TestNetworkTracker oldInfraNetworkTracker = mInfraNetworkTracker;
-        try {
-            setUpInfraNetwork();
-            mInfraNetworkReader = newPacketReader(mInfraNetworkTracker.getTestIface(), mHandler);
-            startInfraDeviceAndWaitForOnLinkAddr();
+        setUpInfraNetwork();
+        mInfraNetworkReader = newPacketReader(mInfraNetworkTracker.getTestIface(), mHandler);
+        startInfraDeviceAndWaitForOnLinkAddr();
 
-            mInfraDevice.sendEchoRequest(ftd.getOmrAddress());
+        mInfraDevice.sendEchoRequest(ftd.getOmrAddress());
 
-            assertNotNull(pollForIcmpPacketOnInfraNetwork(ICMPV6_ECHO_REPLY_TYPE, ftdOmr));
-        } finally {
-            runAsShell(MANAGE_TEST_NETWORKS, () -> oldInfraNetworkTracker.teardown());
-        }
+        assertNotNull(pollForIcmpPacketOnInfraNetwork(ICMPV6_ECHO_REPLY_TYPE, ftdOmr));
     }
 
     @Test
@@ -615,8 +611,6 @@
         subscribeMulticastAddressAndWait(ftd, GROUP_ADDR_SCOPE_5);
         Inet6Address ftdOmr = ftd.getOmrAddress();
 
-        // Destroy infra link and re-create
-        tearDownInfraNetwork();
         setUpInfraNetwork();
         mInfraNetworkReader = newPacketReader(mInfraNetworkTracker.getTestIface(), mHandler);
         startInfraDeviceAndWaitForOnLinkAddr();
@@ -642,8 +636,6 @@
         joinNetworkAndWaitForOmr(ftd, DEFAULT_DATASET);
         Inet6Address ftdOmr = ftd.getOmrAddress();
 
-        // Destroy infra link and re-create
-        tearDownInfraNetwork();
         setUpInfraNetwork();
         mInfraNetworkReader = newPacketReader(mInfraNetworkTracker.getTestIface(), mHandler);
         startInfraDeviceAndWaitForOnLinkAddr();
@@ -683,7 +675,7 @@
     @Test
     public void nat64_withAilNat64Prefix_threadDevicePingIpv4InfraDevice_outboundPacketIsForwarded()
             throws Exception {
-        tearDownInfraNetwork();
+        TestTunNetworkUtils.tearDownInfraNetwork(mInfraNetworkTracker);
         LinkProperties lp = new LinkProperties();
         // NAT64 feature requires the infra network to have an IPv4 default route.
         lp.addRoute(
@@ -701,7 +693,7 @@
                         RouteInfo.RTN_UNICAST,
                         1500 /* mtu */));
         lp.setNat64Prefix(AIL_NAT64_PREFIX);
-        mInfraNetworkTracker = IntegrationTestUtils.setUpInfraNetwork(mContext, mController, lp);
+        mInfraNetworkTracker = TestTunNetworkUtils.setUpInfraNetwork(mContext, mController, lp);
         mInfraNetworkReader = newPacketReader(mInfraNetworkTracker.getTestIface(), mHandler);
         FullThreadDevice ftd = mFtds.get(0);
         joinNetworkAndWaitForOmr(ftd, DEFAULT_DATASET);
@@ -717,16 +709,12 @@
     }
 
     private void setUpInfraNetwork() throws Exception {
-        mInfraNetworkTracker = IntegrationTestUtils.setUpInfraNetwork(mContext, mController);
-    }
-
-    private void tearDownInfraNetwork() {
-        IntegrationTestUtils.tearDownInfraNetwork(mInfraNetworkTracker);
+        mInfraNetworkTracker = TestTunNetworkUtils.setUpInfraNetwork(mContext, mController);
     }
 
     private void startInfraDeviceAndWaitForOnLinkAddr() {
         mInfraDevice =
-                IntegrationTestUtils.startInfraDeviceAndWaitForOnLinkAddr(mInfraNetworkReader);
+                TestTunNetworkUtils.startInfraDeviceAndWaitForOnLinkAddr(mInfraNetworkReader);
     }
 
     private void assertInfraLinkMemberOfGroup(Inet6Address address) throws Exception {
diff --git a/thread/tests/integration/src/android/net/thread/InternetAccessTest.kt b/thread/tests/integration/src/android/net/thread/InternetAccessTest.kt
index 162f58e..cb00611 100644
--- a/thread/tests/integration/src/android/net/thread/InternetAccessTest.kt
+++ b/thread/tests/integration/src/android/net/thread/InternetAccessTest.kt
@@ -28,12 +28,10 @@
 import android.net.thread.utils.IntegrationTestUtils.joinNetworkAndWaitForOmr
 import android.net.thread.utils.IntegrationTestUtils.leaveNetworkAndDisableThread
 import android.net.thread.utils.IntegrationTestUtils.newPacketReader
-import android.net.thread.utils.IntegrationTestUtils.setUpInfraNetwork
-import android.net.thread.utils.IntegrationTestUtils.startInfraDeviceAndWaitForOnLinkAddr
-import android.net.thread.utils.IntegrationTestUtils.tearDownInfraNetwork
 import android.net.thread.utils.IntegrationTestUtils.waitFor
 import android.net.thread.utils.OtDaemonController
 import android.net.thread.utils.TestDnsServer
+import android.net.thread.utils.TestTunNetworkUtils
 import android.net.thread.utils.TestUdpEchoServer
 import android.net.thread.utils.ThreadFeatureCheckerRule
 import android.net.thread.utils.ThreadFeatureCheckerRule.RequiresSimulationThreadDevice
@@ -128,11 +126,11 @@
         handler = Handler(handlerThread.looper)
         ftds = ArrayList()
 
-        infraNetworkTracker = setUpInfraNetwork(context, controller)
+        infraNetworkTracker = TestTunNetworkUtils.setUpInfraNetwork(context, controller)
 
         // Create an infra network device.
         infraNetworkReader = newPacketReader(infraNetworkTracker.testIface, handler)
-        infraDevice = startInfraDeviceAndWaitForOnLinkAddr(infraNetworkReader)
+        infraDevice = TestTunNetworkUtils.startInfraDeviceAndWaitForOnLinkAddr(infraNetworkReader)
 
         // Create a DNS server
         dnsServer = TestDnsServer(infraNetworkReader, DNS_SERVER_ADDR, ANSWER_RECORDS)
@@ -150,7 +148,7 @@
     @Throws(Exception::class)
     fun tearDown() {
         controller.setTestNetworkAsUpstreamAndWait(null)
-        tearDownInfraNetwork(infraNetworkTracker)
+        TestTunNetworkUtils.tearDownAllInfraNetworks()
 
         dnsServer.stop()
         udpEchoServer.stop()
diff --git a/thread/tests/integration/src/android/net/thread/utils/IntegrationTestUtils.kt b/thread/tests/integration/src/android/net/thread/utils/IntegrationTestUtils.kt
index c3859c1..07d0390 100644
--- a/thread/tests/integration/src/android/net/thread/utils/IntegrationTestUtils.kt
+++ b/thread/tests/integration/src/android/net/thread/utils/IntegrationTestUtils.kt
@@ -649,57 +649,6 @@
         )
     }
 
-    private fun defaultLinkProperties(): LinkProperties {
-        val lp = LinkProperties()
-        // TODO: use a fake DNS server
-        lp.setDnsServers(listOf(parseNumericAddress("8.8.8.8")))
-        // NAT64 feature requires the infra network to have an IPv4 default route.
-        lp.addRoute(
-            RouteInfo(
-                IpPrefix("0.0.0.0/0") /* destination */,
-                null /* gateway */,
-                null /* iface */,
-                RouteInfo.RTN_UNICAST, 1500 /* mtu */
-            )
-        )
-        return lp
-    }
-
-    @JvmStatic
-    @JvmOverloads
-    fun startInfraDeviceAndWaitForOnLinkAddr(
-            pollPacketReader: PollPacketReader,
-            macAddress: MacAddress = MacAddress.fromString("1:2:3:4:5:6")
-    ): InfraNetworkDevice {
-        val infraDevice = InfraNetworkDevice(macAddress, pollPacketReader)
-        infraDevice.runSlaac(Duration.ofSeconds(60))
-        requireNotNull(infraDevice.ipv6Addr)
-        return infraDevice
-    }
-
-    @JvmStatic
-    @JvmOverloads
-    @Throws(java.lang.Exception::class)
-    fun setUpInfraNetwork(
-        context: Context,
-        controller: ThreadNetworkControllerWrapper,
-        lp: LinkProperties = defaultLinkProperties()
-    ): TestNetworkTracker {
-        val infraNetworkTracker: TestNetworkTracker =
-            runAsShell(
-                MANAGE_TEST_NETWORKS,
-                supplier = { initTestNetwork(context, lp, setupTimeoutMs = 5000) })
-        val infraNetworkName: String = infraNetworkTracker.testIface.getInterfaceName()
-        controller.setTestNetworkAsUpstreamAndWait(infraNetworkName)
-
-        return infraNetworkTracker
-    }
-
-    @JvmStatic
-    fun tearDownInfraNetwork(testNetworkTracker: TestNetworkTracker) {
-        runAsShell(MANAGE_TEST_NETWORKS) { testNetworkTracker.teardown() }
-    }
-
     /**
      * Stop the ot-daemon by shell command.
      */
diff --git a/thread/tests/integration/src/android/net/thread/utils/TestTunNetworkUtils.kt b/thread/tests/integration/src/android/net/thread/utils/TestTunNetworkUtils.kt
new file mode 100644
index 0000000..1667980
--- /dev/null
+++ b/thread/tests/integration/src/android/net/thread/utils/TestTunNetworkUtils.kt
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.thread.utils
+
+import android.Manifest.permission.MANAGE_TEST_NETWORKS
+import android.content.Context
+import android.net.InetAddresses.parseNumericAddress
+import android.net.IpPrefix
+import android.net.LinkProperties
+import android.net.MacAddress
+import android.net.RouteInfo
+import com.android.testutils.PollPacketReader
+import com.android.testutils.TestNetworkTracker
+import com.android.testutils.initTestNetwork
+import com.android.testutils.runAsShell
+import java.time.Duration
+
+object TestTunNetworkUtils {
+    private val networkTrackers = mutableListOf<TestNetworkTracker>()
+
+    @JvmStatic
+    @JvmOverloads
+    fun setUpInfraNetwork(
+        context: Context,
+        controller: ThreadNetworkControllerWrapper,
+        lp: LinkProperties = defaultLinkProperties(),
+    ): TestNetworkTracker {
+        val infraNetworkTracker: TestNetworkTracker =
+            runAsShell(
+                MANAGE_TEST_NETWORKS,
+                supplier = { initTestNetwork(context, lp, setupTimeoutMs = 5000) },
+            )
+        val infraNetworkName: String = infraNetworkTracker.testIface.getInterfaceName()
+        controller.setTestNetworkAsUpstreamAndWait(infraNetworkName)
+        networkTrackers.add(infraNetworkTracker)
+
+        return infraNetworkTracker
+    }
+
+    @JvmStatic
+    fun tearDownInfraNetwork(testNetworkTracker: TestNetworkTracker) {
+        runAsShell(MANAGE_TEST_NETWORKS) { testNetworkTracker.teardown() }
+    }
+
+    @JvmStatic
+    fun tearDownAllInfraNetworks() {
+        networkTrackers.forEach { tearDownInfraNetwork(it) }
+        networkTrackers.clear()
+    }
+
+    @JvmStatic
+    @JvmOverloads
+    fun startInfraDeviceAndWaitForOnLinkAddr(
+        pollPacketReader: PollPacketReader,
+        macAddress: MacAddress = MacAddress.fromString("1:2:3:4:5:6"),
+    ): InfraNetworkDevice {
+        val infraDevice = InfraNetworkDevice(macAddress, pollPacketReader)
+        infraDevice.runSlaac(Duration.ofSeconds(60))
+        requireNotNull(infraDevice.ipv6Addr)
+        return infraDevice
+    }
+
+    private fun defaultLinkProperties(): LinkProperties {
+        val lp = LinkProperties()
+        // TODO: use a fake DNS server
+        lp.setDnsServers(listOf(parseNumericAddress("8.8.8.8")))
+        // NAT64 feature requires the infra network to have an IPv4 default route.
+        lp.addRoute(
+            RouteInfo(
+                IpPrefix("0.0.0.0/0") /* destination */,
+                null /* gateway */,
+                null /* iface */,
+                RouteInfo.RTN_UNICAST,
+                1500, /* mtu */
+            )
+        )
+        return lp
+    }
+}