Merge changes I2e556cf5,I5e42005f,I7b766ef6 into main

* changes:
  Remove unused method TetheringConfiguration#isRandomPrefixBaseEnabled()
  PrivateAddressCoordinator: introduce Dependencies class
  PrivateAddressCoordinator: move the special handling of WiFi P2P dedicated IP to IpServer
diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
index 506fa56..7a6df88 100644
--- a/Tethering/src/android/net/ip/IpServer.java
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -124,6 +124,8 @@
     // TODO: have PanService use some visible version of this constant
     private static final String BLUETOOTH_IFACE_ADDR = "192.168.44.1/24";
 
+    private static final String LEGACY_WIFI_P2P_IFACE_ADDRESS = "192.168.49.1/24";
+
     // TODO: have this configurable
     private static final int DHCP_LEASE_TIME_SECS = 3600;
 
@@ -249,6 +251,7 @@
     private final LinkProperties mLinkProperties;
     private final boolean mUsingLegacyDhcp;
     private final int mP2pLeasesSubnetPrefixLength;
+    private final boolean mIsWifiP2pDedicatedIpEnabled;
 
     private final Dependencies mDeps;
 
@@ -313,6 +316,7 @@
         mLinkProperties = new LinkProperties();
         mUsingLegacyDhcp = config.useLegacyDhcpServer();
         mP2pLeasesSubnetPrefixLength = config.getP2pLeasesSubnetPrefixLength();
+        mIsWifiP2pDedicatedIpEnabled = config.shouldEnableWifiP2pDedicatedIp();
         mPrivateAddressCoordinator = addressCoordinator;
         mDeps = deps;
         mTetheringMetrics = tetheringMetrics;
@@ -698,11 +702,18 @@
         return (mInterfaceType == TetheringManager.TETHERING_BLUETOOTH) && !SdkLevel.isAtLeastT();
     }
 
+    private boolean shouldUseWifiP2pDedicatedIp() {
+        return mIsWifiP2pDedicatedIpEnabled
+                && mInterfaceType == TetheringManager.TETHERING_WIFI_P2P;
+    }
+
     private LinkAddress requestIpv4Address(final int scope, final boolean useLastAddress) {
         if (mStaticIpv4ServerAddr != null) return mStaticIpv4ServerAddr;
 
         if (shouldNotConfigureBluetoothInterface()) return new LinkAddress(BLUETOOTH_IFACE_ADDR);
 
+        if (shouldUseWifiP2pDedicatedIp()) return new LinkAddress(LEGACY_WIFI_P2P_IFACE_ADDRESS);
+
         return mPrivateAddressCoordinator.requestDownstreamAddress(this, scope, useLastAddress);
     }
 
diff --git a/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java b/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java
index 1d5df61..50f82cf 100644
--- a/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java
+++ b/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java
@@ -28,6 +28,7 @@
 
 import static java.util.Arrays.asList;
 
+import android.content.Context;
 import android.net.IpPrefix;
 import android.net.LinkAddress;
 import android.net.LinkProperties;
@@ -42,6 +43,7 @@
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.IndentingPrintWriter;
+import com.android.net.module.util.DeviceConfigUtils;
 
 import java.net.Inet4Address;
 import java.net.InetAddress;
@@ -67,6 +69,9 @@
     // WARNING: Keep in sync with chooseDownstreamAddress
     public static final int PREFIX_LENGTH = 24;
 
+    public static final String TETHER_FORCE_RANDOM_PREFIX_BASE_SELECTION =
+            "tether_force_random_prefix_base_selection";
+
     // Upstream monitor would be stopped when tethering is down. When tethering restart, downstream
     // address may be requested before coordinator get current upstream notification. To ensure
     // coordinator do not select conflict downstream prefix, mUpstreamPrefixMap would not be cleared
@@ -79,20 +84,42 @@
     private final List<IpPrefix> mTetheringPrefixes;
     // A supplier that returns ConnectivityManager#getAllNetworks.
     private final Supplier<Network[]> mGetAllNetworksSupplier;
-    private final boolean mIsRandomPrefixBaseEnabled;
-    private final boolean mShouldEnableWifiP2pDedicatedIp;
+    private final Dependencies mDeps;
     // keyed by downstream type(TetheringManager.TETHERING_*).
     private final ArrayMap<AddressKey, LinkAddress> mCachedAddresses;
     private final Random mRandom;
 
+    /** Capture PrivateAddressCoordinator dependencies for injection. */
+    public static class Dependencies {
+        private final Context mContext;
+
+        Dependencies(Context context) {
+            mContext = context;
+        }
+
+        /**
+         * Check whether or not one specific experimental feature is enabled according to {@link
+         * DeviceConfigUtils}.
+         *
+         * @param featureName The feature's name to look up.
+         * @return true if this feature is enabled, or false if disabled.
+         */
+        public boolean isFeatureEnabled(String featureName) {
+            return DeviceConfigUtils.isTetheringFeatureEnabled(mContext, featureName);
+        }
+    }
+
+    public PrivateAddressCoordinator(Supplier<Network[]> getAllNetworksSupplier, Context context) {
+        this(getAllNetworksSupplier, new Dependencies(context));
+    }
+
+    @VisibleForTesting
     public PrivateAddressCoordinator(Supplier<Network[]> getAllNetworksSupplier,
-            boolean isRandomPrefixBase,
-            boolean shouldEnableWifiP2pDedicatedIp) {
+                                     Dependencies deps) {
         mDownstreams = new ArraySet<>();
         mUpstreamPrefixMap = new ArrayMap<>();
         mGetAllNetworksSupplier = getAllNetworksSupplier;
-        mIsRandomPrefixBaseEnabled = isRandomPrefixBase;
-        mShouldEnableWifiP2pDedicatedIp = shouldEnableWifiP2pDedicatedIp;
+        mDeps = deps;
         mCachedAddresses = new ArrayMap<AddressKey, LinkAddress>();
         // Reserved static addresses for bluetooth and wifi p2p.
         mCachedAddresses.put(new AddressKey(TETHERING_BLUETOOTH, CONNECTIVITY_SCOPE_GLOBAL),
@@ -179,11 +206,6 @@
     @Nullable
     public LinkAddress requestDownstreamAddress(final IpServer ipServer, final int scope,
             boolean useLastAddress) {
-        if (mShouldEnableWifiP2pDedicatedIp
-                && ipServer.interfaceType() == TETHERING_WIFI_P2P) {
-            return new LinkAddress(LEGACY_WIFI_P2P_IFACE_ADDRESS);
-        }
-
         final AddressKey addrKey = new AddressKey(ipServer.interfaceType(), scope);
         // This ensures that tethering isn't started on 2 different interfaces with the same type.
         // Once tethering could support multiple interface with the same type,
@@ -212,7 +234,7 @@
     }
 
     private int getRandomPrefixIndex() {
-        if (!mIsRandomPrefixBaseEnabled) return 0;
+        if (!mDeps.isFeatureEnabled(TETHER_FORCE_RANDOM_PREFIX_BASE_SELECTION)) return 0;
 
         final int random = getRandomInt() & 0xffffff;
         // This is to select the starting prefix range (/8, /12, or /16) instead of the actual
diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
index 49bc86e..13b8004 100644
--- a/Tethering/src/com/android/networkstack/tethering/Tethering.java
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -359,10 +359,7 @@
         // Load tethering configuration.
         updateConfiguration();
         mConfig.readEnableSyncSM(mContext);
-        // It is OK for the configuration to be passed to the PrivateAddressCoordinator at
-        // construction time because the only part of the configuration it uses is
-        // shouldEnableWifiP2pDedicatedIp(), and currently do not support changing that.
-        mPrivateAddressCoordinator = mDeps.makePrivateAddressCoordinator(mContext, mConfig);
+        mPrivateAddressCoordinator = mDeps.makePrivateAddressCoordinator(mContext);
 
         // Must be initialized after tethering configuration is loaded because BpfCoordinator
         // constructor needs to use the configuration.
diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java b/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
index c9817c9..b3e9c1b 100644
--- a/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
@@ -182,7 +182,6 @@
     private final int mP2pLeasesSubnetPrefixLength;
 
     private final boolean mEnableWearTethering;
-    private final boolean mRandomPrefixBase;
 
     private final int mUsbTetheringFunction;
     protected final ContentResolver mContentResolver;
@@ -300,8 +299,6 @@
 
         mEnableWearTethering = shouldEnableWearTethering(ctx);
 
-        mRandomPrefixBase = mDeps.isFeatureEnabled(ctx, TETHER_FORCE_RANDOM_PREFIX_BASE_SELECTION);
-
         configLog.log(toString());
     }
 
@@ -390,10 +387,6 @@
         return mEnableWearTethering;
     }
 
-    public boolean isRandomPrefixBaseEnabled() {
-        return mRandomPrefixBase;
-    }
-
     /**
      * Check whether sync SM is enabled then set it to USE_SYNC_SM. This should be called once
      * when tethering is created. Otherwise if the flag is pushed while tethering is enabled,
@@ -455,9 +448,6 @@
         pw.print("mUsbTetheringFunction: ");
         pw.println(isUsingNcm() ? "NCM" : "RNDIS");
 
-        pw.print("mRandomPrefixBase: ");
-        pw.println(mRandomPrefixBase);
-
         pw.print("USE_SYNC_SM: ");
         pw.println(USE_SYNC_SM);
     }
diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringDependencies.java b/Tethering/src/com/android/networkstack/tethering/TetheringDependencies.java
index 81f057c..cc878d5 100644
--- a/Tethering/src/com/android/networkstack/tethering/TetheringDependencies.java
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringDependencies.java
@@ -177,13 +177,9 @@
     /**
      * Make PrivateAddressCoordinator to be used by Tethering.
      */
-    public PrivateAddressCoordinator makePrivateAddressCoordinator(
-            Context ctx, TetheringConfiguration cfg) {
+    public PrivateAddressCoordinator makePrivateAddressCoordinator(Context ctx) {
         final ConnectivityManager cm = ctx.getSystemService(ConnectivityManager.class);
-        return new PrivateAddressCoordinator(
-                cm::getAllNetworks,
-                cfg.isRandomPrefixBaseEnabled(),
-                cfg.shouldEnableWifiP2pDedicatedIp());
+        return new PrivateAddressCoordinator(cm::getAllNetworks, ctx);
     }
 
     /**
diff --git a/Tethering/tests/unit/src/android/net/ip/IpServerTest.java b/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
index 177296a..f7834a3 100644
--- a/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
+++ b/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
@@ -139,6 +139,7 @@
     private static final boolean DEFAULT_USING_BPF_OFFLOAD = true;
     private static final int DEFAULT_SUBNET_PREFIX_LENGTH = 0;
     private static final int P2P_SUBNET_PREFIX_LENGTH = 25;
+    private static final String LEGACY_WIFI_P2P_IFACE_ADDRESS = "192.168.49.1/24";
 
     private static final InterfaceParams TEST_IFACE_PARAMS = new InterfaceParams(
             IFACE_NAME, 42 /* index */, MacAddress.ALL_ZEROS_ADDRESS, 1500 /* defaultMtu */);
@@ -196,6 +197,12 @@
 
     private void initStateMachine(int interfaceType, boolean usingLegacyDhcp,
             boolean usingBpfOffload) throws Exception {
+        initStateMachine(interfaceType, usingLegacyDhcp, usingBpfOffload,
+                false /* shouldEnableWifiP2pDedicatedIp */);
+    }
+
+    private void initStateMachine(int interfaceType, boolean usingLegacyDhcp,
+            boolean usingBpfOffload, boolean shouldEnableWifiP2pDedicatedIp) throws Exception {
         when(mDependencies.getDadProxy(any(), any())).thenReturn(mDadProxy);
         when(mDependencies.getRouterAdvertisementDaemon(any())).thenReturn(mRaDaemon);
         when(mDependencies.getInterfaceParams(IFACE_NAME)).thenReturn(TEST_IFACE_PARAMS);
@@ -213,6 +220,8 @@
         when(mTetherConfig.isBpfOffloadEnabled()).thenReturn(usingBpfOffload);
         when(mTetherConfig.useLegacyDhcpServer()).thenReturn(usingLegacyDhcp);
         when(mTetherConfig.getP2pLeasesSubnetPrefixLength()).thenReturn(P2P_SUBNET_PREFIX_LENGTH);
+        when(mTetherConfig.shouldEnableWifiP2pDedicatedIp())
+                .thenReturn(shouldEnableWifiP2pDedicatedIp);
         when(mBpfCoordinator.isUsingBpfOffload()).thenReturn(usingBpfOffload);
         mIpServer = createIpServer(interfaceType);
         mIpServer.start();
@@ -409,7 +418,7 @@
     }
 
     @Test
-    public void canBeTetheredAsWifiP2p() throws Exception {
+    public void canBeTetheredAsWifiP2p_NotUsingDedicatedIp() throws Exception {
         initStateMachine(TETHERING_WIFI_P2P);
 
         dispatchCommand(IpServer.CMD_TETHER_REQUESTED, STATE_LOCAL_ONLY);
@@ -431,6 +440,33 @@
     }
 
     @Test
+    public void canBeTetheredAsWifiP2p_UsingDedicatedIp() throws Exception {
+        initStateMachine(TETHERING_WIFI_P2P, false /* usingLegacyDhcp */, DEFAULT_USING_BPF_OFFLOAD,
+                true /* shouldEnableWifiP2pDedicatedIp */);
+
+        dispatchCommand(IpServer.CMD_TETHER_REQUESTED, STATE_LOCAL_ONLY);
+        InOrder inOrder = inOrder(mCallback, mNetd, mAddressCoordinator);
+        // When using WiFi P2p dedicated IP, the IpServer just picks the IP address without
+        // requesting for it at PrivateAddressCoordinator.
+        inOrder.verify(mAddressCoordinator, never()).requestDownstreamAddress(any(), anyInt(),
+                anyBoolean());
+        inOrder.verify(mNetd).interfaceSetCfg(argThat(cfg ->
+                IFACE_NAME.equals(cfg.ifName) && assertNotContainsFlag(cfg.flags, IF_STATE_UP)));
+        inOrder.verify(mNetd).tetherInterfaceAdd(IFACE_NAME);
+        inOrder.verify(mNetd).networkAddInterface(INetd.LOCAL_NET_ID, IFACE_NAME);
+        inOrder.verify(mNetd, times(2)).networkAddRoute(eq(INetd.LOCAL_NET_ID), eq(IFACE_NAME),
+                any(), any());
+        inOrder.verify(mCallback).updateInterfaceState(
+                mIpServer, STATE_LOCAL_ONLY, TETHER_ERROR_NO_ERROR);
+        inOrder.verify(mCallback).updateLinkProperties(
+                eq(mIpServer), mLinkPropertiesCaptor.capture());
+        assertIPv4AddressAndDirectlyConnectedRoute(mLinkPropertiesCaptor.getValue());
+        assertEquals(List.of(new LinkAddress(LEGACY_WIFI_P2P_IFACE_ADDRESS)),
+                mLinkPropertiesCaptor.getValue().getLinkAddresses());
+        verifyNoMoreInteractions(mNetd, mCallback, mAddressCoordinator);
+    }
+
+    @Test
     public void handlesFirstUpstreamChange() throws Exception {
         initTetheredStateMachine(TETHERING_BLUETOOTH, null);
 
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/PrivateAddressCoordinatorTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/PrivateAddressCoordinatorTest.java
index a5c06f3..bff1fda 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/PrivateAddressCoordinatorTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/PrivateAddressCoordinatorTest.java
@@ -25,6 +25,7 @@
 import static android.net.TetheringManager.TETHERING_WIFI;
 import static android.net.TetheringManager.TETHERING_WIFI_P2P;
 
+import static com.android.networkstack.tethering.PrivateAddressCoordinator.TETHER_FORCE_RANDOM_PREFIX_BASE_SELECTION;
 import static com.android.networkstack.tethering.util.PrefixUtils.asIpPrefix;
 
 import static org.junit.Assert.assertEquals;
@@ -71,7 +72,7 @@
     @Mock private IpServer mWifiP2pIpServer;
     @Mock private Context mContext;
     @Mock private ConnectivityManager mConnectivityMgr;
-    @Mock private TetheringConfiguration mConfig;
+    @Mock private PrivateAddressCoordinator.Dependencies mDeps;
 
     private PrivateAddressCoordinator mPrivateAddressCoordinator;
     private final LinkAddress mBluetoothAddress = new LinkAddress("192.168.44.1/24");
@@ -106,15 +107,9 @@
         when(mContext.getSystemService(Context.CONNECTIVITY_SERVICE)).thenReturn(mConnectivityMgr);
         when(mContext.getSystemService(ConnectivityManager.class)).thenReturn(mConnectivityMgr);
         when(mConnectivityMgr.getAllNetworks()).thenReturn(mAllNetworks);
-        when(mConfig.shouldEnableWifiP2pDedicatedIp()).thenReturn(false);
-        when(mConfig.isRandomPrefixBaseEnabled()).thenReturn(false);
         setUpIpServers();
         mPrivateAddressCoordinator =
-                spy(
-                        new PrivateAddressCoordinator(
-                                mConnectivityMgr::getAllNetworks,
-                                mConfig.isRandomPrefixBaseEnabled(),
-                                mConfig.shouldEnableWifiP2pDedicatedIp()));
+                spy(new PrivateAddressCoordinator(mConnectivityMgr::getAllNetworks, mDeps));
     }
 
     private LinkAddress requestDownstreamAddress(final IpServer ipServer, int scope,
@@ -282,24 +277,6 @@
     }
 
     @Test
-    public void testEnableLegacyWifiP2PAddress() throws Exception {
-        when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(
-                getSubAddress(mLegacyWifiP2pAddress.getAddress().getAddress()));
-        // No matter #shouldEnableWifiP2pDedicatedIp() is enabled or not, legacy wifi p2p prefix
-        // is resevered.
-        assertReseveredWifiP2pPrefix();
-
-        when(mConfig.shouldEnableWifiP2pDedicatedIp()).thenReturn(true);
-        assertReseveredWifiP2pPrefix();
-
-        // If #shouldEnableWifiP2pDedicatedIp() is enabled, wifi P2P gets the configured address.
-        LinkAddress address = requestDownstreamAddress(mWifiP2pIpServer,
-                CONNECTIVITY_SCOPE_LOCAL, true /* useLastAddress */);
-        assertEquals(mLegacyWifiP2pAddress, address);
-        mPrivateAddressCoordinator.releaseDownstream(mWifiP2pIpServer);
-    }
-
-    @Test
     public void testEnableSapAndLohsConcurrently() throws Exception {
         final LinkAddress hotspotAddress = requestDownstreamAddress(mHotspotIpServer,
                 CONNECTIVITY_SCOPE_GLOBAL, true /* useLastAddress */);
@@ -317,7 +294,7 @@
 
     @Test
     public void testStartedPrefixRange() throws Exception {
-        when(mConfig.isRandomPrefixBaseEnabled()).thenReturn(true);
+        when(mDeps.isFeatureEnabled(TETHER_FORCE_RANDOM_PREFIX_BASE_SELECTION)).thenReturn(true);
 
         startedPrefixBaseTest("192.168.0.0/16", 0);
 
@@ -343,11 +320,7 @@
     private void startedPrefixBaseTest(final String expected, final int randomIntForPrefixBase)
             throws Exception {
         mPrivateAddressCoordinator =
-                spy(
-                        new PrivateAddressCoordinator(
-                                mConnectivityMgr::getAllNetworks,
-                                mConfig.isRandomPrefixBaseEnabled(),
-                                mConfig.shouldEnableWifiP2pDedicatedIp()));
+                spy(new PrivateAddressCoordinator(mConnectivityMgr::getAllNetworks, mDeps));
         when(mPrivateAddressCoordinator.getRandomInt()).thenReturn(randomIntForPrefixBase);
         final LinkAddress address = requestDownstreamAddress(mHotspotIpServer,
                 CONNECTIVITY_SCOPE_GLOBAL, false /* useLastAddress */);
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
index 9a4945e..66fe957 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
@@ -71,6 +71,7 @@
 import static com.android.net.module.util.NetworkStackConstants.RFC7421_PREFIX_LENGTH;
 import static com.android.networkstack.tethering.OffloadHardwareInterface.OFFLOAD_HAL_VERSION_HIDL_1_0;
 import static com.android.networkstack.tethering.OffloadHardwareInterface.OFFLOAD_HAL_VERSION_NONE;
+import static com.android.networkstack.tethering.PrivateAddressCoordinator.TETHER_FORCE_RANDOM_PREFIX_BASE_SELECTION;
 import static com.android.networkstack.tethering.TestConnectivityManager.BROADCAST_FIRST;
 import static com.android.networkstack.tethering.TestConnectivityManager.CALLBACKS_FIRST;
 import static com.android.networkstack.tethering.Tethering.UserRestrictionActionListener;
@@ -293,6 +294,7 @@
     @Mock private TetheredInterfaceRequestShim mTetheredInterfaceRequestShim;
     @Mock private TetheringMetrics mTetheringMetrics;
     @Mock private RoutingCoordinatorManager mRoutingCoordinatorManager;
+    @Mock private PrivateAddressCoordinator.Dependencies mPrivateAddressCoordinatorDependencies;
 
     private final MockIpServerDependencies mIpServerDependencies =
             spy(new MockIpServerDependencies());
@@ -535,9 +537,11 @@
         }
 
         @Override
-        public PrivateAddressCoordinator makePrivateAddressCoordinator(Context ctx,
-                TetheringConfiguration cfg) {
-            mPrivateAddressCoordinator = super.makePrivateAddressCoordinator(ctx, cfg);
+        public PrivateAddressCoordinator makePrivateAddressCoordinator(Context ctx) {
+            ConnectivityManager cm = ctx.getSystemService(ConnectivityManager.class);
+            mPrivateAddressCoordinator =
+                    new PrivateAddressCoordinator(
+                            cm::getAllNetworks, mPrivateAddressCoordinatorDependencies);
             return mPrivateAddressCoordinator;
         }
 
@@ -664,6 +668,8 @@
                 .thenReturn(true);
         initOffloadConfiguration(OFFLOAD_HAL_VERSION_HIDL_1_0, 0 /* defaultDisabled */);
         when(mOffloadHardwareInterface.getForwardedStats(any())).thenReturn(mForwardedStats);
+        when(mPrivateAddressCoordinatorDependencies.isFeatureEnabled(anyString()))
+                .thenReturn(false);
 
         mServiceContext = new TestContext(mContext);
         mServiceContext.setUseRegisteredHandlers(true);