In order to use the Ethernet bridging functionality, you'll need the

  userspace tools.
  
  Documentation for Linux bridging is on:
     http://www.linuxfoundation.org/collaborate/workgroups/networking/bridge
  
  The bridge-utilities are maintained at:
     git://git.kernel.org/pub/scm/linux/kernel/git/shemminger/bridge-utils.git
  
  Additionally, the iproute2 utilities can be used to configure
  bridge devices.

  
  If you still have questions, don't hesitate to post to the mailing list 

  (more info https://lists.linux-foundation.org/mailman/listinfo/bridge).