check_ethernet: add fallback to any recently seen neighbor

Jetstream mesh devices do not have a default gateway before
the mesh is established. This was causing the check_ethernet
hook to fail if there was no active SSH connection to the DUT.

This adds a fallback to ping any recently seen neighbor.

TEST=Checked fallback on devices with no default gateway and no
  active ssh connection.

Change-Id: I36f416e10d9d5e0f2db71c9b67210ea210b184c6
Commit-Ready: Laurence Goodby <>
Tested-by: Laurence Goodby <>
Reviewed-by: Richard Barnette <>
Reviewed-by: Grant Grundler <>
1 file changed