Cleanup the TetheredClients API

Add comments to getters as requested in API review, and remove the
expirationTime private field that was planned to be replaced with
LinkAddress expiration.

Test: atest TetheringTests
Fixes: 150878126
Change-Id: Iecf65859cdeeaac2fa7b817b4f505c510424ac89
Merged-In: Iecf65859cdeeaac2fa7b817b4f505c510424ac89
(cherry picked from commit 594d0eae38c13e2bb03de0b3ae1f8781991c321e)

Tethering/common/TetheringLib/src/android/net/TetheredClient.java

@@ -64,16 +64,26 @@ public final class TetheredClient implements Parcelable {
         dest.writeInt(mTetheringType);
     }
 
+    /**
+     * Get the MAC address used to identify the client.
+     */
     @NonNull
     public MacAddress getMacAddress() {
         return mMacAddress;
     }
 
+    /**
+     * Get information on the list of addresses that are associated with the client.
+     */
     @NonNull
     public List<AddressInfo> getAddresses() {
         return new ArrayList<>(mAddresses);
     }
 
+    /**
+     * Get the type of tethering used by the client.
+     * @return one of the {@code TetheringManager#TETHERING_*} constants.
+     */
     public int getTetheringType() {
         return mTetheringType;
     }
@@ -115,45 +125,47 @@ public final class TetheredClient implements Parcelable {
         private final LinkAddress mAddress;
         @Nullable
         private final String mHostname;
-        // TODO: use LinkAddress expiration time once it is supported
-        private final long mExpirationTime;
 
         /** @hide */
         public AddressInfo(@NonNull LinkAddress address, @Nullable String hostname) {
-            this(address, hostname, 0);
-        }
-
-        /** @hide */
-        public AddressInfo(@NonNull LinkAddress address, String hostname, long expirationTime) {
             this.mAddress = address;
             this.mHostname = hostname;
-            this.mExpirationTime = expirationTime;
         }
 
         private AddressInfo(Parcel in) {
-            this(in.readParcelable(null),  in.readString(), in.readLong());
+            this(in.readParcelable(null),  in.readString());
         }
 
         @Override
         public void writeToParcel(@NonNull Parcel dest, int flags) {
             dest.writeParcelable(mAddress, flags);
             dest.writeString(mHostname);
-            dest.writeLong(mExpirationTime);
         }
 
+        /**
+         * Get the link address (including prefix length and lifetime) used by the client.
+         *
+         * This may be an IPv4 or IPv6 address.
+         */
         @NonNull
         public LinkAddress getAddress() {
             return mAddress;
         }
 
+        /**
+         * Get the hostname that was advertised by the client when obtaining its address, if any.
+         */
         @Nullable
         public String getHostname() {
             return mHostname;
         }
 
-        /** @hide TODO: use expiration time in LinkAddress */
+        /**
+         * Get the expiration time of the address assigned to the client.
+         * @hide
+         */
         public long getExpirationTime() {
-            return mExpirationTime;
+            return mAddress.getExpirationTime();
         }
 
         @Override
@@ -163,7 +175,7 @@ public final class TetheredClient implements Parcelable {
 
         @Override
         public int hashCode() {
-            return Objects.hash(mAddress, mHostname, mExpirationTime);
+            return Objects.hash(mAddress, mHostname);
         }
 
         @Override
@@ -173,8 +185,7 @@ public final class TetheredClient implements Parcelable {
             // Use .equals() for addresses as all changes, including address expiry changes,
             // should be included.
             return other.mAddress.equals(mAddress)
-                    && Objects.equals(mHostname, other.mHostname)
+                    && Objects.equals(mHostname, other.mHostname);
-                    && mExpirationTime == other.mExpirationTime;
         }
 
         @NonNull

Tethering/src/android/net/ip/IpServer.java

@@ -24,6 +24,7 @@ import static android.net.util.NetworkConstants.FF;
 import static android.net.util.NetworkConstants.RFC7421_PREFIX_LENGTH;
 import static android.net.util.NetworkConstants.asByte;
 import static android.net.util.TetheringMessageBase.BASE_IPSERVER;
+import static android.system.OsConstants.RT_SCOPE_UNIVERSE;
 
 import android.net.INetd;
 import android.net.INetworkStackStatusCallback;
@@ -448,7 +449,9 @@ public class IpServer extends StateMachine {
             final ArrayList<TetheredClient> leases = new ArrayList<>();
             for (DhcpLeaseParcelable lease : leaseParcelables) {
                 final LinkAddress address = new LinkAddress(
-                        intToInet4AddressHTH(lease.netAddr), lease.prefixLength);
+                        intToInet4AddressHTH(lease.netAddr), lease.prefixLength,
+                        0 /* flags */, RT_SCOPE_UNIVERSE /* as per RFC6724#3.2 */,
+                        lease.expTime /* deprecationTime */, lease.expTime /* expirationTime */);
 
                 final MacAddress macAddress;
                 try {
@@ -460,7 +463,7 @@ public class IpServer extends StateMachine {
                 }
 
                 final TetheredClient.AddressInfo addressInfo = new TetheredClient.AddressInfo(
-                        address, lease.hostname, lease.expTime);
+                        address, lease.hostname);
                 leases.add(new TetheredClient(
                         macAddress,
                         Collections.singletonList(addressInfo),

Tethering/tests/unit/src/android/net/TetheredClientTest.kt

@@ -20,6 +20,7 @@ import android.net.InetAddresses.parseNumericAddress
 import android.net.TetheredClient.AddressInfo
 import android.net.TetheringManager.TETHERING_BLUETOOTH
 import android.net.TetheringManager.TETHERING_USB
+import android.system.OsConstants.RT_SCOPE_UNIVERSE
 import androidx.test.filters.SmallTest
 import androidx.test.runner.AndroidJUnit4
 import com.android.testutils.assertParcelSane
@@ -30,11 +31,19 @@ import kotlin.test.assertNotEquals
 
 private val TEST_MACADDR = MacAddress.fromBytes(byteArrayOf(12, 23, 34, 45, 56, 67))
 private val TEST_OTHER_MACADDR = MacAddress.fromBytes(byteArrayOf(23, 34, 45, 56, 67, 78))
-private val TEST_ADDR1 = LinkAddress(parseNumericAddress("192.168.113.3"), 24)
+private val TEST_ADDR1 = makeLinkAddress("192.168.113.3", prefixLength = 24, expTime = 123L)
-private val TEST_ADDR2 = LinkAddress(parseNumericAddress("fe80::1:2:3"), 64)
+private val TEST_ADDR2 = makeLinkAddress("fe80::1:2:3", prefixLength = 64, expTime = 456L)
 private val TEST_ADDRINFO1 = AddressInfo(TEST_ADDR1, "test_hostname")
 private val TEST_ADDRINFO2 = AddressInfo(TEST_ADDR2, null)
 
+private fun makeLinkAddress(addr: String, prefixLength: Int, expTime: Long) = LinkAddress(
+        parseNumericAddress(addr),
+        prefixLength,
+        0 /* flags */,
+        RT_SCOPE_UNIVERSE,
+        expTime /* deprecationTime */,
+        expTime /* expirationTime */)
+
 @RunWith(AndroidJUnit4::class)
 @SmallTest
 class TetheredClientTest {

Tethering/tests/unit/src/com/android/server/connectivity/tethering/ConnectedClientsTrackerTest.kt

@@ -46,23 +46,28 @@ class ConnectedClientsTrackerTest {
 
     private val client1Addr = MacAddress.fromString("01:23:45:67:89:0A")
     private val client1 = TetheredClient(client1Addr, listOf(
-            AddressInfo(LinkAddress("192.168.43.44/32"), null /* hostname */, clock.time + 20)),
+            makeAddrInfo("192.168.43.44/32", null /* hostname */, clock.time + 20)),
             TETHERING_WIFI)
     private val wifiClient1 = makeWifiClient(client1Addr)
     private val client2Addr = MacAddress.fromString("02:34:56:78:90:AB")
-    private val client2Exp30AddrInfo = AddressInfo(
+    private val client2Exp30AddrInfo = makeAddrInfo(
-            LinkAddress("192.168.43.45/32"), "my_hostname", clock.time + 30)
+            "192.168.43.45/32", "my_hostname", clock.time + 30)
     private val client2 = TetheredClient(client2Addr, listOf(
             client2Exp30AddrInfo,
-            AddressInfo(LinkAddress("2001:db8:12::34/72"), "other_hostname", clock.time + 10)),
+            makeAddrInfo("2001:db8:12::34/72", "other_hostname", clock.time + 10)),
             TETHERING_WIFI)
     private val wifiClient2 = makeWifiClient(client2Addr)
     private val client3Addr = MacAddress.fromString("03:45:67:89:0A:BC")
     private val client3 = TetheredClient(client3Addr,
-            listOf(AddressInfo(LinkAddress("2001:db8:34::34/72"), "other_other_hostname",
+            listOf(makeAddrInfo("2001:db8:34::34/72", "other_other_hostname", clock.time + 10)),
-                    clock.time + 10)),
             TETHERING_USB)
 
+    private fun makeAddrInfo(addr: String, hostname: String?, expTime: Long) =
+            LinkAddress(addr).let {
+                AddressInfo(LinkAddress(it.address, it.prefixLength, it.flags, it.scope,
+                        expTime /* deprecationTime */, expTime /* expirationTime */), hostname)
+            }
+
     @Test
     fun testUpdateConnectedClients() {
         doReturn(emptyList<TetheredClient>()).`when`(server1).allLeases