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).