Fix tethering WTF issue

When enable/disable tethering quickly, tethering may have stopped
when Ipserver start creatFd().
As tethering iface is down due to tethering stopped, creatFd() will
throw ErrnoException: bind failed: ENODEV (No such device).
When tethering is stopped, this exception is normal, should not
rise WTF.

Bug: 233587050
Test: manual test
Change-Id: I2e200313d1bec2c1e1245e779f3875397127160d
diff --git a/Tethering/src/android/net/ip/NeighborPacketForwarder.java b/Tethering/src/android/net/ip/NeighborPacketForwarder.java
index 723bd63..8384562 100644
--- a/Tethering/src/android/net/ip/NeighborPacketForwarder.java
+++ b/Tethering/src/android/net/ip/NeighborPacketForwarder.java
@@ -23,6 +23,7 @@
 import static android.system.OsConstants.SOCK_DGRAM;
 import static android.system.OsConstants.SOCK_NONBLOCK;
 import static android.system.OsConstants.SOCK_RAW;
+import static android.system.OsConstants.ENODEV;
 
 import android.net.util.SocketUtils;
 import android.os.Handler;
@@ -131,7 +132,13 @@
                                                         ETH_P_IPV6, mListenIfaceParams.index);
             Os.bind(mFd, bindAddress);
         } catch (ErrnoException | SocketException e) {
-            Log.wtf(mTag, "Failed to create  socket", e);
+            // An ENODEV(No such device) will rise if tethering stopped before this function, this
+            // may happen when enable/disable tethering quickly.
+            if (e instanceof ErrnoException && ((ErrnoException) e).errno == ENODEV) {
+                Log.w(mTag, "Failed to create socket because tethered interface is gone", e);
+            } else {
+                Log.wtf(mTag, "Failed to create socket", e);
+            }
             closeSocketQuietly(mFd);
             return null;
         }