Revert "Restore the default interface MTU when disconnecting from Wi-Fi AP."

This reverts commit 98ed332579d20a8304b5cdbba761d49bcad75fd3.

Reason for revert: prepare another CL to fix the possible NPE issue.
Test: atest NetworkStackIntegrationTests

Change-Id: I9237b31625299162dca1c2b3e012858413639081

2 files changed, 3 insertions, 38 deletions

diff --git a/src/android/net/ip/IpClient.java b/src/android/net/ip/IpClient.java
index bff30b6..799184e 100644
--- a/src/android/net/ip/IpClient.java
+++ b/src/android/net/ip/IpClient.java
@@ -19,7 +19,6 @@ package android.net.ip;
 import static android.net.RouteInfo.RTN_UNICAST;
 import static android.net.shared.IpConfigurationParcelableUtil.toStableParcelable;
 
-import static com.android.server.util.NetworkStackConstants.ETHER_MTU;
 import static com.android.server.util.PermissionUtil.checkNetworkStackCallingPermission;
 
 import android.annotation.NonNull;
@@ -49,7 +48,6 @@ import android.os.ConditionVariable;
 import android.os.IBinder;
 import android.os.Message;
 import android.os.RemoteException;
-import android.os.ServiceSpecificException;
 import android.os.SystemClock;
 import android.text.TextUtils;
 import android.util.LocalLog;
@@ -71,8 +69,6 @@ import com.android.server.NetworkStackService.NetworkStackServiceManager;
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
 import java.net.InetAddress;
-import java.net.NetworkInterface;
-import java.net.SocketException;
 import java.util.Collection;
 import java.util.List;
 import java.util.Objects;
@@ -384,8 +380,6 @@ public class IpClient extends StateMachine {
     private final ConditionVariable mApfDataSnapshotComplete = new ConditionVariable();
 
     public static class Dependencies {
-        private static final String TAG = "IpClient.Dependencies";
-
         /**
          * Get interface parameters for the specified interface.
          */
@@ -394,18 +388,6 @@ public class IpClient extends StateMachine {
         }
 
         /**
-         * Get the current MTU for the specified interface.
-         */
-        public int getInterfaceMtu(String ifname) {
-            try {
-                return NetworkInterface.getByName(ifname).getMTU();
-            } catch (SocketException e) {
-                Log.e(TAG, "unexpected failure to get the interface MTU");
-                return ETHER_MTU;
-            }
-        }
-
-        /**
          * Get a INetd connector.
          */
         public INetd getNetd(Context context) {
@@ -868,14 +850,10 @@ public class IpClient extends StateMachine {
         return shouldLog;
     }
 
-    private void logError(String fmt, Throwable e, Object... args) {
-        final String msg = "ERROR " + String.format(fmt, args);
-        Log.e(mTag, msg, e);
-        mLog.e(msg, e);
-    }
-
     private void logError(String fmt, Object... args) {
-        logError(fmt, null, args);
+        final String msg = "ERROR " + String.format(fmt, args);
+        Log.e(mTag, msg);
+        mLog.log(msg);
     }
 
     // This needs to be called with care to ensure that our LinkProperties
@@ -1373,17 +1351,6 @@ public class IpClient extends StateMachine {
                 // There's no DHCPv4 for which to wait; proceed to stopped.
                 deferMessage(obtainMessage(CMD_JUMP_STOPPING_TO_STOPPED));
             }
-
-            // Restore the interface MTU to initial value if it has changed.
-            final int mtu = mDependencies.getInterfaceMtu(mInterfaceName);
-            try {
-                if (mtu != mInterfaceParams.defaultMtu) {
-                    mNetd.interfaceSetMtu(mInterfaceName, mInterfaceParams.defaultMtu);
-                }
-            } catch (RemoteException | ServiceSpecificException e) {
-                logError("Couldn't reset MTU from "
-                        + mtu + " to " + mInterfaceParams.defaultMtu + ": " + e);
-            }
         }
 
         @Override
diff --git a/src/com/android/server/util/NetworkStackConstants.java b/src/com/android/server/util/NetworkStackConstants.java
index 3174a9b..804765e 100644
--- a/src/com/android/server/util/NetworkStackConstants.java
+++ b/src/com/android/server/util/NetworkStackConstants.java
@@ -54,7 +54,6 @@ public final class NetworkStackConstants {
     public static final int ETHER_TYPE_IPV4 = 0x0800;
     public static final int ETHER_TYPE_IPV6 = 0x86dd;
     public static final int ETHER_HEADER_LEN = 14;
-    public static final int ETHER_MTU = 1500;
 
     /**
      * ARP constants.
@@ -98,7 +97,6 @@ public final class NetworkStackConstants {
     public static final int IPV6_PROTOCOL_OFFSET = 6;
     public static final int IPV6_SRC_ADDR_OFFSET = 8;
     public static final int IPV6_DST_ADDR_OFFSET = 24;
-    public static final int IPV6_MIN_MTU = 1280;
 
     /**
      * ICMPv6 constants.