Revert "Simplify addRoutesToLocalNetwork calls"

Revert submission 2777667

Reason for revert: DroidMonitor-triggered revert due to breakage, bug b/305187495

Reverted changes: /q/submissionid:2777667

Bug: 305187495

Change-Id: I516d40b20d775e9c61b2f825bc094329d016d0c3

Tethering/tests/privileged/src/android/net/ip/RouterAdvertisementDaemonTest.java

@@ -16,6 +16,8 @@
 
 package android.net.ip;
 
+import static android.net.RouteInfo.RTN_UNICAST;
+
 import static com.android.net.module.util.NetworkStackConstants.ETHER_HEADER_LEN;
 import static com.android.net.module.util.NetworkStackConstants.ETHER_TYPE_IPV6;
 import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ND_OPTION_MTU;
@@ -40,13 +42,12 @@ import android.content.Context;
 import android.net.INetd;
 import android.net.IpPrefix;
 import android.net.MacAddress;
+import android.net.RouteInfo;
 import android.net.ip.RouterAdvertisementDaemon.RaParams;
 import android.os.Handler;
 import android.os.HandlerThread;
 import android.os.IBinder;
 import android.os.Looper;
-import android.os.RemoteException;
-import android.os.ServiceSpecificException;
 
 import androidx.test.InstrumentationRegistry;
 import androidx.test.filters.SmallTest;
@@ -54,6 +55,7 @@ import androidx.test.runner.AndroidJUnit4;
 
 import com.android.net.module.util.InterfaceParams;
 import com.android.net.module.util.Ipv6Utils;
+import com.android.net.module.util.NetdUtils;
 import com.android.net.module.util.Struct;
 import com.android.net.module.util.structs.EthernetHeader;
 import com.android.net.module.util.structs.Icmpv6Header;
@@ -78,6 +80,7 @@ import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.nio.ByteBuffer;
 import java.util.HashSet;
+import java.util.List;
 
 @RunWith(AndroidJUnit4.class)
 @SmallTest
@@ -329,12 +332,10 @@ public final class RouterAdvertisementDaemonTest {
         // Add a default route "fe80::/64 -> ::" to local network, otherwise, device will fail to
         // send the unicast RA out due to the ENETUNREACH error(No route to the peer's link-local
         // address is present).
-        try {
-            sNetd.networkAddRoute(INetd.LOCAL_NET_ID, mTetheredParams.name,
-                    "fe80::/64", INetd.NEXTHOP_NONE);
-        } catch (RemoteException | ServiceSpecificException e) {
-            throw new IllegalStateException(e);
-        }
+        final String iface = mTetheredParams.name;
+        final RouteInfo linkLocalRoute =
+                new RouteInfo(new IpPrefix("fe80::/64"), null, iface, RTN_UNICAST);
+        NetdUtils.addRoutesToLocalNetwork(sNetd, iface, List.of(linkLocalRoute));
 
         final ByteBuffer rs = createRsPacket("fe80::1122:3344:5566:7788");
         mTetheredPacketReader.sendResponse(rs);

staticlibs/client-libs/netd/com/android/net/module/util/NetdUtils.java

@@ -159,11 +159,9 @@ public class NetdUtils {
             throws RemoteException, ServiceSpecificException {
         netd.tetherInterfaceAdd(iface);
         networkAddInterface(netd, iface, maxAttempts, pollingIntervalMs);
-        // Activate a route to dest and IPv6 link local.
-        modifyRoute(netd, ModifyOperation.ADD, INetd.LOCAL_NET_ID,
-                new RouteInfo(dest, null, iface, RTN_UNICAST));
-        modifyRoute(netd, ModifyOperation.ADD, INetd.LOCAL_NET_ID,
-                new RouteInfo(new IpPrefix("fe80::/64"), null, iface, RTN_UNICAST));
+        List<RouteInfo> routes = new ArrayList<>();
+        routes.add(new RouteInfo(dest, null, iface, RTN_UNICAST));
+        addRoutesToLocalNetwork(netd, iface, routes);
     }
 
     /**