Merge changes I943d4efb,I02378125,I2ee4ae52

* changes:
  Reset the generated v6 clat address when stop
  Add helper method to translate v4 address pair to clat v6
  Add methods to provide clat source address

service/src/com/android/server/connectivity/Nat464Xlat.java

@@ -44,7 +44,9 @@ import com.android.net.module.util.NetworkStackConstants;
 import com.android.server.ConnectivityService;
 
 import java.io.IOException;
+import java.net.Inet4Address;
 import java.net.Inet6Address;
+import java.net.UnknownHostException;
 import java.util.Objects;
 
 /**
@@ -99,7 +101,8 @@ public class Nat464Xlat {
     private IpPrefix mNat64PrefixFromRa;
     private String mBaseIface;
     private String mIface;
-    private Inet6Address mIPv6Address;
+    @VisibleForTesting
+    Inet6Address mIPv6Address;
     private State mState = State.IDLE;
     private final ClatCoordinator mClatCoordinator;  // non-null iff T+
 
@@ -239,6 +242,7 @@ public class Nat464Xlat {
         mNat64PrefixInUse = null;
         mIface = null;
         mBaseIface = null;
+        mIPv6Address = null;
 
         if (!mPrefixDiscoveryRunning) {
             setPrefix64(null);
@@ -540,6 +544,52 @@ public class Nat464Xlat {
         mNetwork.handler().post(() -> handleInterfaceRemoved(iface));
     }
 
+    /**
+     * Translate the input v4 address to v6 clat address.
+     */
+    @Nullable
+    public Inet6Address translateV4toV6(@NonNull Inet4Address addr) {
+        // Variables in Nat464Xlat should only be accessed from handler thread.
+        ensureRunningOnHandlerThread();
+        if (!isStarted()) return null;
+
+        return convertv4ToClatv6(mNat64PrefixInUse, addr);
+    }
+
+    @Nullable
+    private static Inet6Address convertv4ToClatv6(
+            @NonNull IpPrefix prefix, @NonNull Inet4Address addr) {
+        final byte[] v6Addr = new byte[16];
+        // Generate a v6 address from Nat64 prefix. Prefix should be 12 bytes long.
+        System.arraycopy(prefix.getAddress().getAddress(), 0, v6Addr, 0, 12);
+        System.arraycopy(addr.getAddress(), 0, v6Addr, 12, 4);
+
+        try {
+            return (Inet6Address) Inet6Address.getByAddress(v6Addr);
+        } catch (UnknownHostException e) {
+            Log.e(TAG, "getByAddress should never throw for a numeric address");
+            return null;
+        }
+    }
+
+    /**
+     * Get the generated v6 address of clat.
+     */
+    @Nullable
+    public Inet6Address getClatv6SrcAddress() {
+        // Variables in Nat464Xlat should only be accessed from handler thread.
+        ensureRunningOnHandlerThread();
+
+        return mIPv6Address;
+    }
+
+    private void ensureRunningOnHandlerThread() {
+        if (mNetwork.handler().getLooper().getThread() != Thread.currentThread()) {
+            throw new IllegalStateException(
+                    "Not running on handler thread: " + Thread.currentThread().getName());
+        }
+    }
+
     /**
      * Dump the NAT64 xlat information.
      *

service/src/com/android/server/connectivity/NetworkAgentInfo.java

@@ -68,6 +68,8 @@ import com.android.modules.utils.build.SdkLevel;
 import com.android.server.ConnectivityService;
 
 import java.io.PrintWriter;
+import java.net.Inet4Address;
+import java.net.Inet6Address;
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -1032,6 +1034,22 @@ public class NetworkAgentInfo implements NetworkRanker.Scoreable {
         return network;
     }
 
+    /**
+     * Get the generated v6 address of clat.
+     */
+    @Nullable
+    public Inet6Address getClatv6SrcAddress() {
+        return clatd.getClatv6SrcAddress();
+    }
+
+    /**
+     * Translate the input v4 address to v6 clat address.
+     */
+    @Nullable
+    public Inet6Address translateV4toClatV6(@NonNull Inet4Address addr) {
+        return clatd.translateV4toV6(addr);
+    }
+
     /**
      * Get the NetworkMonitorManager in this NetworkAgentInfo.
      *

tests/unit/java/com/android/server/connectivity/Nat464XlatTest.java

@@ -20,10 +20,12 @@ import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.anyString;
+import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.never;
@@ -72,6 +74,7 @@ public class Nat464XlatTest {
     static final String STACKED_IFACE = "v4-test0";
     static final LinkAddress V6ADDR = new LinkAddress("2001:db8:1::f00/64");
     static final LinkAddress ADDR = new LinkAddress("192.0.2.5/29");
+    static final String CLAT_V6 = "64:ff9b::1";
     static final String NAT64_PREFIX = "64:ff9b::/96";
     static final String OTHER_NAT64_PREFIX = "2001:db8:0:64::/96";
     static final int NETID = 42;
@@ -132,6 +135,8 @@ public class Nat464XlatTest {
         when(mNetd.interfaceGetCfg(eq(STACKED_IFACE))).thenReturn(mConfig);
         mConfig.ipv4Addr = ADDR.getAddress().getHostAddress();
         mConfig.prefixLength =  ADDR.getPrefixLength();
+        doReturn(CLAT_V6).when(mClatCoordinator).clatStart(
+                BASE_IFACE, NETID, new IpPrefix(NAT64_PREFIX));
     }
 
     private void assertRequiresClat(boolean expected, NetworkAgentInfo nai) {
@@ -286,7 +291,8 @@ public class Nat464XlatTest {
         assertFalse(c.getValue().getAllInterfaceNames().contains(STACKED_IFACE));
         verify(mDnsResolver).stopPrefix64Discovery(eq(NETID));
         assertIdle(nat);
-
+        // Verify the generated v6 is reset when clat is stopped.
+        assertNull(nat.mIPv6Address);
         // Stacked interface removed notification arrives and is ignored.
         nat.interfaceRemoved(STACKED_IFACE);
         mLooper.dispatchNext();