bridge: fix bridge root block on designated port
Root port blocking was designed so that a bridge port can opt
out of becoming the designated root port for a bridge. If a port
however first becomes the designated root port and we then toggle
the root port block on it we currently don't kick that port out of
the designated root port. This fixes that. This is particularly
important for net_devices that would wish to never become a root
port from the start, currently toggling that off will enable root
port flag but it won't really kick the bridge and do what you'd
expect, the MAC address is kept on the bridge of the toggled port
for root_block if it was the designated port.
In order to catch if a port with root port block preference is set
we need to move our check for root block prior to the root selection
so check for root blocked ports upon eveyr br_configuration_update().
We also simply just prevent the root-blocked ports from consideration
as root port candidates on br_should_become_root_port() and
br_stp_recalculate_bridge_id().
The issue that this patch is trying to address and fix can be tested
easily before and after this patch is applied using 2 TAP net_devices
and then toggling at will with the root_block knob.
ip tuntap add dev tap0 mode tap
ip tuntap add dev tap1 mode tap
ip link add dev br0 type bridge
ip link show br0
echo -------------------------------------------
ip link set dev tap0 master br0
ip link
echo -------------------------------------------
ip link set dev tap1 master br0
ip link
echo -------------------------------------------
Upon review at the above results you can toggle root_block
on each port to see if you see the results you expect.
bridge link set dev tap0 root_block on
ip link
bridge link set dev tap1 root_block on
ip link
Toggling off root_block on any port should will bring back the
port to be a candidate for designated root port:
bridge link set dev tap1 root_block off
ip link
bridge link set dev tap0 root_block off
ip link
To nuke:
ip tuntap del tap0 mode tap
ip tuntap del tap0 mode tap
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: bridge@lists.linux-foundation.org
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: xen-devel@lists.xenproject.org
Cc: kvm@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
4 files changed
