Merge changes I0d0c0fac,Ifb9b00b6

* changes:
  Split updateCapabilities into two methods.
  More strictly check NetworkCapabilities callbacks.
diff --git a/core/java/android/net/MacAddress.java b/core/java/android/net/MacAddress.java
index d6992aa..287bdc8 100644
--- a/core/java/android/net/MacAddress.java
+++ b/core/java/android/net/MacAddress.java
@@ -17,6 +17,7 @@
 package android.net;
 
 import android.annotation.IntDef;
+import android.annotation.NonNull;
 import android.os.Parcel;
 import android.os.Parcelable;
 
@@ -60,7 +61,7 @@
     })
     public @interface MacAddressType { }
 
-    /** Indicates a MAC address of unknown type. */
+    /** @hide Indicates a MAC address of unknown type. */
     public static final int TYPE_UNKNOWN = 0;
     /** Indicates a MAC address is a unicast address. */
     public static final int TYPE_UNICAST = 1;
@@ -92,7 +93,7 @@
      *
      * @return the int constant representing the MAC address type of this MacAddress.
      */
-    public @MacAddressType int addressType() {
+    public @MacAddressType int getAddressType() {
         if (equals(BROADCAST_ADDRESS)) {
             return TYPE_BROADCAST;
         }
@@ -120,12 +121,12 @@
     /**
      * @return a byte array representation of this MacAddress.
      */
-    public byte[] toByteArray() {
+    public @NonNull byte[] toByteArray() {
         return byteAddrFromLongAddr(mAddr);
     }
 
     @Override
-    public String toString() {
+    public @NonNull String toString() {
         return stringAddrFromLongAddr(mAddr);
     }
 
@@ -133,7 +134,7 @@
      * @return a String representation of the OUI part of this MacAddress made of 3 hexadecimal
      * numbers in [0,ff] joined by ':' characters.
      */
-    public String toOuiString() {
+    public @NonNull String toOuiString() {
         return String.format(
                 "%02x:%02x:%02x", (mAddr >> 40) & 0xff, (mAddr >> 32) & 0xff, (mAddr >> 24) & 0xff);
     }
@@ -197,7 +198,7 @@
         if (!isMacAddress(addr)) {
             return TYPE_UNKNOWN;
         }
-        return MacAddress.fromBytes(addr).addressType();
+        return MacAddress.fromBytes(addr).getAddressType();
     }
 
     /**
@@ -211,7 +212,7 @@
      *
      * @hide
      */
-    public static byte[] byteAddrFromStringAddr(String addr) {
+    public static @NonNull byte[] byteAddrFromStringAddr(String addr) {
         Preconditions.checkNotNull(addr);
         String[] parts = addr.split(":");
         if (parts.length != ETHER_ADDR_LEN) {
@@ -239,7 +240,7 @@
      *
      * @hide
      */
-    public static String stringAddrFromByteAddr(byte[] addr) {
+    public static @NonNull String stringAddrFromByteAddr(byte[] addr) {
         if (!isMacAddress(addr)) {
             return null;
         }
@@ -291,7 +292,7 @@
 
     // Internal conversion function equivalent to stringAddrFromByteAddr(byteAddrFromLongAddr(addr))
     // that avoids the allocation of an intermediary byte[].
-    private static String stringAddrFromLongAddr(long addr) {
+    private static @NonNull String stringAddrFromLongAddr(long addr) {
         return String.format("%02x:%02x:%02x:%02x:%02x:%02x",
                 (addr >> 40) & 0xff,
                 (addr >> 32) & 0xff,
@@ -310,7 +311,7 @@
      * @return the MacAddress corresponding to the given String representation.
      * @throws IllegalArgumentException if the given String is not a valid representation.
      */
-    public static MacAddress fromString(String addr) {
+    public static @NonNull MacAddress fromString(@NonNull String addr) {
         return new MacAddress(longAddrFromStringAddr(addr));
     }
 
@@ -322,7 +323,7 @@
      * @return the MacAddress corresponding to the given byte array representation.
      * @throws IllegalArgumentException if the given byte array is not a valid representation.
      */
-    public static MacAddress fromBytes(byte[] addr) {
+    public static @NonNull MacAddress fromBytes(@NonNull byte[] addr) {
         return new MacAddress(longAddrFromByteAddr(addr));
     }
 
@@ -336,7 +337,7 @@
      *
      * @hide
      */
-    public static MacAddress createRandomUnicastAddress() {
+    public static @NonNull MacAddress createRandomUnicastAddress() {
         return createRandomUnicastAddress(BASE_GOOGLE_MAC, new Random());
     }
 
@@ -352,7 +353,7 @@
      *
      * @hide
      */
-    public static MacAddress createRandomUnicastAddress(MacAddress base, Random r) {
+    public static @NonNull MacAddress createRandomUnicastAddress(MacAddress base, Random r) {
         long addr = (base.mAddr & OUI_MASK) | (NIC_MASK & r.nextLong());
         addr = addr | LOCALLY_ASSIGNED_MASK;
         addr = addr & ~MULTICAST_MASK;
diff --git a/core/java/android/net/Network.java b/core/java/android/net/Network.java
index 903b602..3683d34 100644
--- a/core/java/android/net/Network.java
+++ b/core/java/android/net/Network.java
@@ -356,13 +356,13 @@
         // Multiple Provisioning Domains API recommendations, as made by the
         // IETF mif working group.
         //
-        // The HANDLE_MAGIC value MUST be kept in sync with the corresponding
+        // The handleMagic value MUST be kept in sync with the corresponding
         // value in the native/android/net.c NDK implementation.
         if (netId == 0) {
             return 0L;  // make this zero condition obvious for debugging
         }
-        final long HANDLE_MAGIC = 0xfacade;
-        return (((long) netId) << 32) | HANDLE_MAGIC;
+        final long handleMagic = 0xcafed00dL;
+        return (((long) netId) << 32) | handleMagic;
     }
 
     // implement the Parcelable interface
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index b19e482..ed1e011 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -130,6 +130,7 @@
 import com.android.internal.util.XmlUtils;
 import com.android.server.am.BatteryStatsService;
 import com.android.server.connectivity.DataConnectionStats;
+import com.android.server.connectivity.DnsManager;
 import com.android.server.connectivity.IpConnectivityMetrics;
 import com.android.server.connectivity.KeepaliveTracker;
 import com.android.server.connectivity.LingerMonitor;
@@ -224,7 +225,11 @@
     @GuardedBy("mVpns")
     private final SparseArray<Vpn> mVpns = new SparseArray<Vpn>();
 
+    // TODO: investigate if mLockdownEnabled can be removed and replaced everywhere by
+    // a direct call to LockdownVpnTracker.isEnabled().
+    @GuardedBy("mVpns")
     private boolean mLockdownEnabled;
+    @GuardedBy("mVpns")
     private LockdownVpnTracker mLockdownTracker;
 
     final private Context mContext;
@@ -232,8 +237,6 @@
     // 0 is full bad, 100 is full good
     private int mDefaultInetConditionPublished = 0;
 
-    private int mNumDnsEntries;
-
     private boolean mTestMode;
     private static ConnectivityService sServiceInstance;
 
@@ -407,6 +410,7 @@
     final private InternalHandler mHandler;
     /** Handler used for incoming {@link NetworkStateTracker} events. */
     final private NetworkStateTrackerHandler mTrackerHandler;
+    private final DnsManager mDnsManager;
 
     private boolean mSystemReady;
     private Intent mInitialBroadcast;
@@ -857,6 +861,8 @@
         mMultinetworkPolicyTracker = createMultinetworkPolicyTracker(
                 mContext, mHandler, () -> rematchForAvoidBadWifiUpdate());
         mMultinetworkPolicyTracker.start();
+
+        mDnsManager = new DnsManager(mContext, mNetd, mSystemProperties);
     }
 
     private Tethering makeTethering() {
@@ -972,9 +978,9 @@
     }
 
     private Network[] getVpnUnderlyingNetworks(int uid) {
-        if (!mLockdownEnabled) {
-            int user = UserHandle.getUserId(uid);
-            synchronized (mVpns) {
+        synchronized (mVpns) {
+            if (!mLockdownEnabled) {
+                int user = UserHandle.getUserId(uid);
                 Vpn vpn = mVpns.get(user);
                 if (vpn != null && vpn.appliesToUid(uid)) {
                     return vpn.getUnderlyingNetworks();
@@ -1062,8 +1068,10 @@
         if (isNetworkWithLinkPropertiesBlocked(state.linkProperties, uid, ignoreBlocked)) {
             state.networkInfo.setDetailedState(DetailedState.BLOCKED, null, null);
         }
-        if (mLockdownTracker != null) {
-            mLockdownTracker.augmentNetworkInfo(state.networkInfo);
+        synchronized (mVpns) {
+            if (mLockdownTracker != null) {
+                mLockdownTracker.augmentNetworkInfo(state.networkInfo);
+            }
         }
     }
 
@@ -1228,8 +1236,8 @@
             result.put(nai.network, nc);
         }
 
-        if (!mLockdownEnabled) {
-            synchronized (mVpns) {
+        synchronized (mVpns) {
+            if (!mLockdownEnabled) {
                 Vpn vpn = mVpns.get(userId);
                 if (vpn != null) {
                     Network[] networks = vpn.getUnderlyingNetworks();
@@ -1555,9 +1563,11 @@
     }
 
     private Intent makeGeneralIntent(NetworkInfo info, String bcastType) {
-        if (mLockdownTracker != null) {
-            info = new NetworkInfo(info);
-            mLockdownTracker.augmentNetworkInfo(info);
+        synchronized (mVpns) {
+            if (mLockdownTracker != null) {
+                info = new NetworkInfo(info);
+                mLockdownTracker.augmentNetworkInfo(info);
+            }
         }
 
         Intent intent = new Intent(bcastType);
@@ -1803,24 +1813,6 @@
         }
     }
 
-    private void flushVmDnsCache() {
-        /*
-         * Tell the VMs to toss their DNS caches
-         */
-        Intent intent = new Intent(Intent.ACTION_CLEAR_DNS_CACHE);
-        intent.addFlags(Intent.FLAG_RECEIVER_REPLACE_PENDING);
-        /*
-         * Connectivity events can happen before boot has completed ...
-         */
-        intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
-        final long ident = Binder.clearCallingIdentity();
-        try {
-            mContext.sendBroadcastAsUser(intent, UserHandle.ALL);
-        } finally {
-            Binder.restoreCallingIdentity(ident);
-        }
-    }
-
     @Override
     public int getRestoreDefaultNetworkDelay(int networkType) {
         String restoreDefaultNetworkDelayStr = mSystemProperties.get(
@@ -2488,6 +2480,7 @@
     private void handleRemoveNetworkRequest(final NetworkRequestInfo nri) {
         nri.unlinkDeathRecipient();
         mNetworkRequests.remove(nri.request);
+
         synchronized (mUidToNetworkRequestCount) {
             int requests = mUidToNetworkRequestCount.get(nri.mUid, 0);
             if (requests < 1) {
@@ -2500,6 +2493,7 @@
                 mUidToNetworkRequestCount.put(nri.mUid, requests - 1);
             }
         }
+
         mNetworkRequestInfoLogs.log("RELEASE " + nri);
         if (nri.request.isRequest()) {
             boolean wasKept = false;
@@ -3422,9 +3416,9 @@
     public boolean prepareVpn(@Nullable String oldPackage, @Nullable String newPackage,
             int userId) {
         enforceCrossUserPermission(userId);
-        throwIfLockdownEnabled();
 
         synchronized (mVpns) {
+            throwIfLockdownEnabled();
             Vpn vpn = mVpns.get(userId);
             if (vpn != null) {
                 return vpn.prepare(oldPackage, newPackage);
@@ -3468,9 +3462,9 @@
      */
     @Override
     public ParcelFileDescriptor establishVpn(VpnConfig config) {
-        throwIfLockdownEnabled();
         int user = UserHandle.getUserId(Binder.getCallingUid());
         synchronized (mVpns) {
+            throwIfLockdownEnabled();
             return mVpns.get(user).establish(config);
         }
     }
@@ -3481,13 +3475,13 @@
      */
     @Override
     public void startLegacyVpn(VpnProfile profile) {
-        throwIfLockdownEnabled();
+        int user = UserHandle.getUserId(Binder.getCallingUid());
         final LinkProperties egress = getActiveLinkProperties();
         if (egress == null) {
             throw new IllegalStateException("Missing active network connection");
         }
-        int user = UserHandle.getUserId(Binder.getCallingUid());
         synchronized (mVpns) {
+            throwIfLockdownEnabled();
             mVpns.get(user).startLegacyVpn(profile, mKeyStore, egress);
         }
     }
@@ -3513,11 +3507,11 @@
     @Override
     public VpnInfo[] getAllVpnInfo() {
         enforceConnectivityInternalPermission();
-        if (mLockdownEnabled) {
-            return new VpnInfo[0];
-        }
-
         synchronized (mVpns) {
+            if (mLockdownEnabled) {
+                return new VpnInfo[0];
+            }
+
             List<VpnInfo> infoList = new ArrayList<>();
             for (int i = 0; i < mVpns.size(); i++) {
                 VpnInfo info = createVpnInfo(mVpns.valueAt(i));
@@ -3582,33 +3576,33 @@
             return false;
         }
 
-        // Tear down existing lockdown if profile was removed
-        mLockdownEnabled = LockdownVpnTracker.isEnabled();
-        if (mLockdownEnabled) {
-            byte[] profileTag = mKeyStore.get(Credentials.LOCKDOWN_VPN);
-            if (profileTag == null) {
-                Slog.e(TAG, "Lockdown VPN configured but cannot be read from keystore");
-                return false;
-            }
-            String profileName = new String(profileTag);
-            final VpnProfile profile = VpnProfile.decode(
-                    profileName, mKeyStore.get(Credentials.VPN + profileName));
-            if (profile == null) {
-                Slog.e(TAG, "Lockdown VPN configured invalid profile " + profileName);
-                setLockdownTracker(null);
-                return true;
-            }
-            int user = UserHandle.getUserId(Binder.getCallingUid());
-            synchronized (mVpns) {
+        synchronized (mVpns) {
+            // Tear down existing lockdown if profile was removed
+            mLockdownEnabled = LockdownVpnTracker.isEnabled();
+            if (mLockdownEnabled) {
+                byte[] profileTag = mKeyStore.get(Credentials.LOCKDOWN_VPN);
+                if (profileTag == null) {
+                    Slog.e(TAG, "Lockdown VPN configured but cannot be read from keystore");
+                    return false;
+                }
+                String profileName = new String(profileTag);
+                final VpnProfile profile = VpnProfile.decode(
+                        profileName, mKeyStore.get(Credentials.VPN + profileName));
+                if (profile == null) {
+                    Slog.e(TAG, "Lockdown VPN configured invalid profile " + profileName);
+                    setLockdownTracker(null);
+                    return true;
+                }
+                int user = UserHandle.getUserId(Binder.getCallingUid());
                 Vpn vpn = mVpns.get(user);
                 if (vpn == null) {
                     Slog.w(TAG, "VPN for user " + user + " not ready yet. Skipping lockdown");
                     return false;
                 }
                 setLockdownTracker(new LockdownVpnTracker(mContext, mNetd, this, vpn, profile));
+            } else {
+                setLockdownTracker(null);
             }
-        } else {
-            setLockdownTracker(null);
         }
 
         return true;
@@ -3618,6 +3612,7 @@
      * Internally set new {@link LockdownVpnTracker}, shutting down any existing
      * {@link LockdownVpnTracker}. Can be {@code null} to disable lockdown.
      */
+    @GuardedBy("mVpns")
     private void setLockdownTracker(LockdownVpnTracker tracker) {
         // Shutdown any existing tracker
         final LockdownVpnTracker existing = mLockdownTracker;
@@ -3632,6 +3627,7 @@
         }
     }
 
+    @GuardedBy("mVpns")
     private void throwIfLockdownEnabled() {
         if (mLockdownEnabled) {
             throw new IllegalStateException("Unavailable in lockdown mode");
@@ -3679,12 +3675,12 @@
         enforceConnectivityInternalPermission();
         enforceCrossUserPermission(userId);
 
-        // Can't set always-on VPN if legacy VPN is already in lockdown mode.
-        if (LockdownVpnTracker.isEnabled()) {
-            return false;
-        }
-
         synchronized (mVpns) {
+            // Can't set always-on VPN if legacy VPN is already in lockdown mode.
+            if (LockdownVpnTracker.isEnabled()) {
+                return false;
+            }
+
             Vpn vpn = mVpns.get(userId);
             if (vpn == null) {
                 Slog.w(TAG, "User " + userId + " has no Vpn configuration");
@@ -3860,9 +3856,9 @@
             }
             userVpn = new Vpn(mHandler.getLooper(), mContext, mNetd, userId);
             mVpns.put(userId, userVpn);
-        }
-        if (mUserManager.getUserInfo(userId).isPrimary() && LockdownVpnTracker.isEnabled()) {
-            updateLockdownVpn();
+            if (mUserManager.getUserInfo(userId).isPrimary() && LockdownVpnTracker.isEnabled()) {
+                updateLockdownVpn();
+            }
         }
     }
 
@@ -3899,11 +3895,13 @@
     }
 
     private void onUserUnlocked(int userId) {
-        // User present may be sent because of an unlock, which might mean an unlocked keystore.
-        if (mUserManager.getUserInfo(userId).isPrimary() && LockdownVpnTracker.isEnabled()) {
-            updateLockdownVpn();
-        } else {
-            startAlwaysOnVpn(userId);
+        synchronized (mVpns) {
+            // User present may be sent because of an unlock, which might mean an unlocked keystore.
+            if (mUserManager.getUserInfo(userId).isPrimary() && LockdownVpnTracker.isEnabled()) {
+                updateLockdownVpn();
+            } else {
+                startAlwaysOnVpn(userId);
+            }
         }
     }
 
@@ -4558,41 +4556,17 @@
             return;  // no updating necessary
         }
 
+        final NetworkAgentInfo defaultNai = getDefaultNetwork();
+        final boolean isDefaultNetwork = (defaultNai != null && defaultNai.network.netId == netId);
+
         Collection<InetAddress> dnses = newLp.getDnsServers();
         if (DBG) log("Setting DNS servers for network " + netId + " to " + dnses);
         try {
-            mNetd.setDnsConfigurationForNetwork(
-                    netId, NetworkUtils.makeStrings(dnses), newLp.getDomains());
+            mDnsManager.setDnsConfigurationForNetwork(
+                    netId, dnses, newLp.getDomains(), isDefaultNetwork);
         } catch (Exception e) {
             loge("Exception in setDnsConfigurationForNetwork: " + e);
         }
-        final NetworkAgentInfo defaultNai = getDefaultNetwork();
-        if (defaultNai != null && defaultNai.network.netId == netId) {
-            setDefaultDnsSystemProperties(dnses);
-        }
-        flushVmDnsCache();
-    }
-
-    private void setDefaultDnsSystemProperties(Collection<InetAddress> dnses) {
-        int last = 0;
-        for (InetAddress dns : dnses) {
-            ++last;
-            setNetDnsProperty(last, dns.getHostAddress());
-        }
-        for (int i = last + 1; i <= mNumDnsEntries; ++i) {
-            setNetDnsProperty(i, "");
-        }
-        mNumDnsEntries = last;
-    }
-
-    private void setNetDnsProperty(int which, String value) {
-        final String key = "net.dns" + which;
-        // Log and forget errors setting unsupported properties.
-        try {
-            mSystemProperties.set(key, value);
-        } catch (Exception e) {
-            Log.e(TAG, "Error setting unsupported net.dns property: ", e);
-        }
     }
 
     private String getNetworkPermission(NetworkCapabilities nc) {
@@ -4880,7 +4854,7 @@
         notifyLockdownVpn(newNetwork);
         handleApplyDefaultProxy(newNetwork.linkProperties.getHttpProxy());
         updateTcpBufferSizes(newNetwork);
-        setDefaultDnsSystemProperties(newNetwork.linkProperties.getDnsServers());
+        mDnsManager.setDefaultDnsSystemProperties(newNetwork.linkProperties.getDnsServers());
     }
 
     private void processListenRequests(NetworkAgentInfo nai, boolean capabilitiesChanged) {
@@ -5230,11 +5204,13 @@
     }
 
     private void notifyLockdownVpn(NetworkAgentInfo nai) {
-        if (mLockdownTracker != null) {
-            if (nai != null && nai.isVPN()) {
-                mLockdownTracker.onVpnStateChanged(nai.networkInfo);
-            } else {
-                mLockdownTracker.onNetworkInfoChanged();
+        synchronized (mVpns) {
+            if (mLockdownTracker != null) {
+                if (nai != null && nai.isVPN()) {
+                    mLockdownTracker.onVpnStateChanged(nai.networkInfo);
+                } else {
+                    mLockdownTracker.onNetworkInfoChanged();
+                }
             }
         }
     }
@@ -5464,28 +5440,28 @@
 
     @Override
     public boolean addVpnAddress(String address, int prefixLength) {
-        throwIfLockdownEnabled();
         int user = UserHandle.getUserId(Binder.getCallingUid());
         synchronized (mVpns) {
+            throwIfLockdownEnabled();
             return mVpns.get(user).addAddress(address, prefixLength);
         }
     }
 
     @Override
     public boolean removeVpnAddress(String address, int prefixLength) {
-        throwIfLockdownEnabled();
         int user = UserHandle.getUserId(Binder.getCallingUid());
         synchronized (mVpns) {
+            throwIfLockdownEnabled();
             return mVpns.get(user).removeAddress(address, prefixLength);
         }
     }
 
     @Override
     public boolean setUnderlyingNetworksForVpn(Network[] networks) {
-        throwIfLockdownEnabled();
         int user = UserHandle.getUserId(Binder.getCallingUid());
-        boolean success;
+        final boolean success;
         synchronized (mVpns) {
+            throwIfLockdownEnabled();
             success = mVpns.get(user).setUnderlyingNetworks(networks);
         }
         if (success) {
@@ -5545,31 +5521,31 @@
                     setAlwaysOnVpnPackage(userId, null, false);
                     setVpnPackageAuthorization(alwaysOnPackage, userId, false);
                 }
-            }
 
-            // Turn Always-on VPN off
-            if (mLockdownEnabled && userId == UserHandle.USER_SYSTEM) {
-                final long ident = Binder.clearCallingIdentity();
-                try {
-                    mKeyStore.delete(Credentials.LOCKDOWN_VPN);
-                    mLockdownEnabled = false;
-                    setLockdownTracker(null);
-                } finally {
-                    Binder.restoreCallingIdentity(ident);
+                // Turn Always-on VPN off
+                if (mLockdownEnabled && userId == UserHandle.USER_SYSTEM) {
+                    final long ident = Binder.clearCallingIdentity();
+                    try {
+                        mKeyStore.delete(Credentials.LOCKDOWN_VPN);
+                        mLockdownEnabled = false;
+                        setLockdownTracker(null);
+                    } finally {
+                        Binder.restoreCallingIdentity(ident);
+                    }
                 }
-            }
 
-            // Turn VPN off
-            VpnConfig vpnConfig = getVpnConfig(userId);
-            if (vpnConfig != null) {
-                if (vpnConfig.legacy) {
-                    prepareVpn(VpnConfig.LEGACY_VPN, VpnConfig.LEGACY_VPN, userId);
-                } else {
-                    // Prevent this app (packagename = vpnConfig.user) from initiating VPN connections
-                    // in the future without user intervention.
-                    setVpnPackageAuthorization(vpnConfig.user, userId, false);
+                // Turn VPN off
+                VpnConfig vpnConfig = getVpnConfig(userId);
+                if (vpnConfig != null) {
+                    if (vpnConfig.legacy) {
+                        prepareVpn(VpnConfig.LEGACY_VPN, VpnConfig.LEGACY_VPN, userId);
+                    } else {
+                        // Prevent this app (packagename = vpnConfig.user) from initiating
+                        // VPN connections in the future without user intervention.
+                        setVpnPackageAuthorization(vpnConfig.user, userId, false);
 
-                    prepareVpn(null, VpnConfig.LEGACY_VPN, userId);
+                        prepareVpn(null, VpnConfig.LEGACY_VPN, userId);
+                    }
                 }
             }
         }
diff --git a/services/core/java/com/android/server/connectivity/DnsManager.java b/services/core/java/com/android/server/connectivity/DnsManager.java
new file mode 100644
index 0000000..a4170ce
--- /dev/null
+++ b/services/core/java/com/android/server/connectivity/DnsManager.java
@@ -0,0 +1,226 @@
+/*
+ * Copyright (C) 2018 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 com.android.server.connectivity;
+
+import static android.net.ConnectivityManager.PRIVATE_DNS_DEFAULT_MODE;
+import static android.net.ConnectivityManager.PRIVATE_DNS_MODE_OPPORTUNISTIC;
+import static android.net.ConnectivityManager.PRIVATE_DNS_MODE_PROVIDER_HOSTNAME;
+import static android.provider.Settings.Global.DNS_RESOLVER_MIN_SAMPLES;
+import static android.provider.Settings.Global.DNS_RESOLVER_MAX_SAMPLES;
+import static android.provider.Settings.Global.DNS_RESOLVER_SAMPLE_VALIDITY_SECONDS;
+import static android.provider.Settings.Global.DNS_RESOLVER_SUCCESS_THRESHOLD_PERCENT;
+import static android.provider.Settings.Global.PRIVATE_DNS_MODE;
+import static android.provider.Settings.Global.PRIVATE_DNS_SPECIFIER;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.Intent;
+import android.net.NetworkUtils;
+import android.os.Binder;
+import android.os.INetworkManagementService;
+import android.os.Handler;
+import android.os.UserHandle;
+import android.provider.Settings;
+import android.text.TextUtils;
+import android.util.Slog;
+
+import com.android.server.connectivity.MockableSystemProperties;
+
+import java.net.InetAddress;
+import java.util.Collection;
+
+
+/**
+ * Encapsulate the management of DNS settings for networks.
+ *
+ * This class it NOT designed for concurrent access. Furthermore, all non-static
+ * methods MUST be called from ConnectivityService's thread.
+ *
+ * @hide
+ */
+public class DnsManager {
+    private static final String TAG = DnsManager.class.getSimpleName();
+
+    /* Defaults for resolver parameters. */
+    private static final int DNS_RESOLVER_DEFAULT_SAMPLE_VALIDITY_SECONDS = 1800;
+    private static final int DNS_RESOLVER_DEFAULT_SUCCESS_THRESHOLD_PERCENT = 25;
+    private static final int DNS_RESOLVER_DEFAULT_MIN_SAMPLES = 8;
+    private static final int DNS_RESOLVER_DEFAULT_MAX_SAMPLES = 64;
+
+    private final Context mContext;
+    private final ContentResolver mContentResolver;
+    private final INetworkManagementService mNMS;
+    private final MockableSystemProperties mSystemProperties;
+
+    private int mNumDnsEntries;
+    private int mSampleValidity;
+    private int mSuccessThreshold;
+    private int mMinSamples;
+    private int mMaxSamples;
+    private String mPrivateDnsMode;
+    private String mPrivateDnsSpecifier;
+
+    public DnsManager(Context ctx, INetworkManagementService nms, MockableSystemProperties sp) {
+        mContext = ctx;
+        mContentResolver = mContext.getContentResolver();
+        mNMS = nms;
+        mSystemProperties = sp;
+
+        // TODO: Create and register ContentObservers to track every setting
+        // used herein, posting messages to respond to changes.
+    }
+
+    public boolean isPrivateDnsInStrictMode() {
+        return !TextUtils.isEmpty(mPrivateDnsMode) &&
+               mPrivateDnsMode.startsWith(PRIVATE_DNS_MODE_PROVIDER_HOSTNAME) &&
+               !TextUtils.isEmpty(mPrivateDnsSpecifier);
+    }
+
+    public void setDnsConfigurationForNetwork(
+            int netId, Collection<InetAddress> servers, String domains, boolean isDefaultNetwork) {
+        updateParametersSettings();
+        updatePrivateDnsSettings();
+
+        final String[] serverStrs = NetworkUtils.makeStrings(servers);
+        final String[] domainStrs = (domains == null) ? new String[0] : domains.split(" ");
+        final int[] params = { mSampleValidity, mSuccessThreshold, mMinSamples, mMaxSamples };
+        final boolean useTls = shouldUseTls(mPrivateDnsMode);
+        // TODO: Populate tlsHostname once it's decided how the hostname's IP
+        // addresses will be resolved:
+        //
+        //     [1] network-provided DNS servers are included here with the
+        //         hostname and netd will use the network-provided servers to
+        //         resolve the hostname and fix up its internal structures, or
+        //
+        //     [2] network-provided DNS servers are included here without the
+        //         hostname, the ConnectivityService layer resolves the given
+        //         hostname, and then reconfigures netd with this information.
+        //
+        // In practice, there will always be a need for ConnectivityService or
+        // the captive portal app to use the network-provided services to make
+        // some queries. This argues in favor of [1], in concert with another
+        // mechanism, perhaps setting a high bit in the netid, to indicate
+        // via existing DNS APIs which set of servers (network-provided or
+        // non-network-provided private DNS) should be queried.
+        final String tlsHostname = "";
+        try {
+            mNMS.setDnsConfigurationForNetwork(
+                    netId, serverStrs, domainStrs, params, useTls, tlsHostname);
+        } catch (Exception e) {
+            Slog.e(TAG, "Error setting DNS configuration: " + e);
+            return;
+        }
+
+        // TODO: netd should listen on [::1]:53 and proxy queries to the current
+        // default network, and we should just set net.dns1 to ::1, not least
+        // because applications attempting to use net.dns resolvers will bypass
+        // the privacy protections of things like DNS-over-TLS.
+        if (isDefaultNetwork) setDefaultDnsSystemProperties(servers);
+        flushVmDnsCache();
+    }
+
+    public void setDefaultDnsSystemProperties(Collection<InetAddress> dnses) {
+        int last = 0;
+        for (InetAddress dns : dnses) {
+            ++last;
+            setNetDnsProperty(last, dns.getHostAddress());
+        }
+        for (int i = last + 1; i <= mNumDnsEntries; ++i) {
+            setNetDnsProperty(i, "");
+        }
+        mNumDnsEntries = last;
+    }
+
+    private void flushVmDnsCache() {
+        /*
+         * Tell the VMs to toss their DNS caches
+         */
+        final Intent intent = new Intent(Intent.ACTION_CLEAR_DNS_CACHE);
+        intent.addFlags(Intent.FLAG_RECEIVER_REPLACE_PENDING);
+        /*
+         * Connectivity events can happen before boot has completed ...
+         */
+        intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
+        final long ident = Binder.clearCallingIdentity();
+        try {
+            mContext.sendBroadcastAsUser(intent, UserHandle.ALL);
+        } finally {
+            Binder.restoreCallingIdentity(ident);
+        }
+    }
+
+    private void updatePrivateDnsSettings() {
+        mPrivateDnsMode = getStringSetting(PRIVATE_DNS_MODE);
+        mPrivateDnsSpecifier = getStringSetting(PRIVATE_DNS_SPECIFIER);
+    }
+
+    private void updateParametersSettings() {
+        mSampleValidity = getIntSetting(
+                DNS_RESOLVER_SAMPLE_VALIDITY_SECONDS,
+                DNS_RESOLVER_DEFAULT_SAMPLE_VALIDITY_SECONDS);
+        if (mSampleValidity < 0 || mSampleValidity > 65535) {
+            Slog.w(TAG, "Invalid sampleValidity=" + mSampleValidity + ", using default=" +
+                    DNS_RESOLVER_DEFAULT_SAMPLE_VALIDITY_SECONDS);
+            mSampleValidity = DNS_RESOLVER_DEFAULT_SAMPLE_VALIDITY_SECONDS;
+        }
+
+        mSuccessThreshold = getIntSetting(
+                DNS_RESOLVER_SUCCESS_THRESHOLD_PERCENT,
+                DNS_RESOLVER_DEFAULT_SUCCESS_THRESHOLD_PERCENT);
+        if (mSuccessThreshold < 0 || mSuccessThreshold > 100) {
+            Slog.w(TAG, "Invalid successThreshold=" + mSuccessThreshold + ", using default=" +
+                    DNS_RESOLVER_DEFAULT_SUCCESS_THRESHOLD_PERCENT);
+            mSuccessThreshold = DNS_RESOLVER_DEFAULT_SUCCESS_THRESHOLD_PERCENT;
+        }
+
+        mMinSamples = getIntSetting(DNS_RESOLVER_MIN_SAMPLES, DNS_RESOLVER_DEFAULT_MIN_SAMPLES);
+        mMaxSamples = getIntSetting(DNS_RESOLVER_MAX_SAMPLES, DNS_RESOLVER_DEFAULT_MAX_SAMPLES);
+        if (mMinSamples < 0 || mMinSamples > mMaxSamples || mMaxSamples > 64) {
+            Slog.w(TAG, "Invalid sample count (min, max)=(" + mMinSamples + ", " + mMaxSamples +
+                    "), using default=(" + DNS_RESOLVER_DEFAULT_MIN_SAMPLES + ", " +
+                    DNS_RESOLVER_DEFAULT_MAX_SAMPLES + ")");
+            mMinSamples = DNS_RESOLVER_DEFAULT_MIN_SAMPLES;
+            mMaxSamples = DNS_RESOLVER_DEFAULT_MAX_SAMPLES;
+        }
+    }
+
+    private String getStringSetting(String which) {
+        return Settings.Global.getString(mContentResolver, which);
+    }
+
+    private int getIntSetting(String which, int dflt) {
+        return Settings.Global.getInt(mContentResolver, which, dflt);
+    }
+
+    private void setNetDnsProperty(int which, String value) {
+        final String key = "net.dns" + which;
+        // Log and forget errors setting unsupported properties.
+        try {
+            mSystemProperties.set(key, value);
+        } catch (Exception e) {
+            Slog.e(TAG, "Error setting unsupported net.dns property: ", e);
+        }
+    }
+
+    private static boolean shouldUseTls(String mode) {
+        if (TextUtils.isEmpty(mode)) {
+            mode = PRIVATE_DNS_DEFAULT_MODE;
+        }
+        return mode.equals(PRIVATE_DNS_MODE_OPPORTUNISTIC) ||
+               mode.startsWith(PRIVATE_DNS_MODE_PROVIDER_HOSTNAME);
+    }
+}
diff --git a/tests/net/java/android/net/MacAddressTest.java b/tests/net/java/android/net/MacAddressTest.java
index 473dc53..9aad413 100644
--- a/tests/net/java/android/net/MacAddressTest.java
+++ b/tests/net/java/android/net/MacAddressTest.java
@@ -67,7 +67,7 @@
             assertEquals(msg, t.expectedType, got);
 
             if (got != MacAddress.TYPE_UNKNOWN) {
-                assertEquals(got, MacAddress.fromBytes(t.addr).addressType());
+                assertEquals(got, MacAddress.fromBytes(t.addr).getAddressType());
             }
         }
     }
@@ -191,7 +191,7 @@
 
             assertTrue(stringRepr + " expected to be a locally assigned address",
                     mac.isLocallyAssigned());
-            assertEquals(MacAddress.TYPE_UNICAST, mac.addressType());
+            assertEquals(MacAddress.TYPE_UNICAST, mac.getAddressType());
             assertTrue(stringRepr + " expected to begin with " + expectedLocalOui,
                     stringRepr.startsWith(expectedLocalOui));
         }
diff --git a/tests/net/java/android/net/NetworkTest.java b/tests/net/java/android/net/NetworkTest.java
index bacf986..94d01e9 100644
--- a/tests/net/java/android/net/NetworkTest.java
+++ b/tests/net/java/android/net/NetworkTest.java
@@ -147,9 +147,9 @@
 
         // Adjust as necessary to test an implementation's specific constants.
         // When running with runtest, "adb logcat -s TestRunner" can be useful.
-        assertEquals(4311403230L, one.getNetworkHandle());
-        assertEquals(8606370526L, two.getNetworkHandle());
-        assertEquals(12901337822L, three.getNetworkHandle());
+        assertEquals(7700664333L, one.getNetworkHandle());
+        assertEquals(11995631629L, two.getNetworkHandle());
+        assertEquals(16290598925L, three.getNetworkHandle());
     }
 
     private static <T> void assertNotEqual(T t1, T t2) {
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index 731c3f1..b8e37f3 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -55,14 +55,20 @@
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
+import static org.mockito.Matchers.anyBoolean;
+import static org.mockito.Matchers.anyInt;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+
 import android.app.NotificationManager;
 import android.app.PendingIntent;
 import android.content.BroadcastReceiver;
@@ -116,6 +122,7 @@
 import android.util.ArraySet;
 import android.util.Log;
 
+import com.android.internal.util.ArrayUtils;
 import com.android.internal.util.WakeupMessage;
 import com.android.internal.util.test.BroadcastInterceptingContext;
 import com.android.internal.util.test.FakeSettingsProvider;
@@ -132,6 +139,7 @@
 import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 import org.mockito.Spy;
@@ -174,8 +182,11 @@
 
     @Mock IpConnectivityMetrics.Logger mMetricsService;
     @Mock DefaultNetworkMetrics mDefaultNetworkMetrics;
+    @Mock INetworkManagementService mNetworkManagementService;
     @Mock INetworkStatsService mStatsService;
 
+    private ArgumentCaptor<String[]> mStringArrayCaptor = ArgumentCaptor.forClass(String[].class);
+
     // This class exists to test bindProcessToNetwork and getBoundNetworkForProcess. These methods
     // do not go through ConnectivityService but talk to netd directly, so they don't automatically
     // reflect the state of our test ConnectivityService.
@@ -872,7 +883,7 @@
         LocalServices.addService(
                 NetworkPolicyManagerInternal.class, mock(NetworkPolicyManagerInternal.class));
         mService = new WrappedConnectivityService(mServiceContext,
-                mock(INetworkManagementService.class),
+                mNetworkManagementService,
                 mStatsService,
                 mock(INetworkPolicyManager.class),
                 mock(IpConnectivityLog.class));
@@ -3521,6 +3532,44 @@
         reset(mStatsService);
     }
 
+    @Test
+    public void testBasicDnsConfigurationPushed() throws Exception {
+        mCellNetworkAgent = new MockNetworkAgent(TRANSPORT_CELLULAR);
+        waitForIdle();
+        verify(mNetworkManagementService, never()).setDnsConfigurationForNetwork(
+                anyInt(), any(), any(), any(), anyBoolean(), anyString());
+
+        final LinkProperties cellLp = new LinkProperties();
+        cellLp.setInterfaceName("test_rmnet_data0");
+        mCellNetworkAgent.sendLinkProperties(cellLp);
+        mCellNetworkAgent.connect(false);
+        waitForIdle();
+        verify(mNetworkManagementService, times(1)).setDnsConfigurationForNetwork(
+                anyInt(), mStringArrayCaptor.capture(), any(), any(), anyBoolean(), anyString());
+        // CS tells netd about the empty DNS config for this network.
+        assertEmpty(mStringArrayCaptor.getValue());
+        reset(mNetworkManagementService);
+
+        cellLp.addDnsServer(InetAddress.getByName("2001:db8::1"));
+        mCellNetworkAgent.sendLinkProperties(cellLp);
+        waitForIdle();
+        verify(mNetworkManagementService, times(1)).setDnsConfigurationForNetwork(
+                anyInt(), mStringArrayCaptor.capture(), any(), any(), anyBoolean(), anyString());
+        assertEquals(1, mStringArrayCaptor.getValue().length);
+        assertTrue(ArrayUtils.contains(mStringArrayCaptor.getValue(), "2001:db8::1"));
+        reset(mNetworkManagementService);
+
+        cellLp.addDnsServer(InetAddress.getByName("192.0.2.1"));
+        mCellNetworkAgent.sendLinkProperties(cellLp);
+        waitForIdle();
+        verify(mNetworkManagementService, times(1)).setDnsConfigurationForNetwork(
+                anyInt(), mStringArrayCaptor.capture(), any(), any(), anyBoolean(), anyString());
+        assertEquals(2, mStringArrayCaptor.getValue().length);
+        assertTrue(ArrayUtils.containsAll(mStringArrayCaptor.getValue(),
+                new String[]{"2001:db8::1", "192.0.2.1"}));
+        reset(mNetworkManagementService);
+    }
+
     private void checkDirectlyConnectedRoutes(Object callbackObj,
             Collection<LinkAddress> linkAddresses, Collection<RouteInfo> otherRoutes) {
         assertTrue(callbackObj instanceof LinkProperties);