linux-stable.git/include/linux/if_bridge.h, branch v5.13.2

net: bridge: add helper to replay VLANs installed on port

2021-03-23T21:49:05+00:00

Currently this simple setup with DSA:

ip link add br0 type bridge vlan_filtering 1
ip link add bond0 type bond
ip link set bond0 master br0
ip link set swp0 master bond0

will not work because the bridge has created the PVID in br_add_if ->
nbp_vlan_init, and it has notified switchdev of the existence of VLAN 1,
but that was too early, since swp0 was not yet a lower of bond0, so it
had no reason to act upon that notification.

We need a helper in the bridge to replay the switchdev VLAN objects that
were notified since the bridge port creation, because some of them may
have been missed.

As opposed to the br_mdb_replay function, the vg->vlan_list write side
protection is offered by the rtnl_mutex which is sleepable, so we don't
need to queue up the objects in atomic context, we can replay them right
away.

Signed-off-by: Vladimir Oltean 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

net: bridge: add helper to replay port and local fdb entries

2021-03-23T21:49:05+00:00

When a switchdev port starts offloading a LAG that is already in a
bridge and has an FDB entry pointing to it:

ip link set bond0 master br0
bridge fdb add dev bond0 00:01:02:03:04:05 master static
ip link set swp0 master bond0

the switchdev driver will have no idea that this FDB entry is there,
because it missed the switchdev event emitted at its creation.

Ido Schimmel pointed this out during a discussion about challenges with
switchdev offloading of stacked interfaces between the physical port and
the bridge, and recommended to just catch that condition and deny the
CHANGEUPPER event:
https://lore.kernel.org/netdev/20210210105949.GB287766@shredder.lan/

But in fact, we might need to deal with the hard thing anyway, which is
to replay all FDB addresses relevant to this port, because it isn't just
static FDB entries, but also local addresses (ones that are not
forwarded but terminated by the bridge). There, we can't just say 'oh
yeah, there was an upper already so I'm not joining that'.

So, similar to the logic for replaying MDB entries, add a function that
must be called by individual switchdev drivers and replays local FDB
entries as well as ones pointing towards a bridge port. This time, we
use the atomic switchdev notifier block, since that's what FDB entries
expect for some reason.

Reported-by: Ido Schimmel 
Signed-off-by: Vladimir Oltean 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

net: bridge: add helper to replay port and host-joined mdb entries

2021-03-23T21:49:05+00:00

I have a system with DSA ports, and udhcpcd is configured to bring
interfaces up as soon as they are created.

I create a bridge as follows:

ip link add br0 type bridge

As soon as I create the bridge and udhcpcd brings it up, I also have
avahi which automatically starts sending IPv6 packets to advertise some
local services, and because of that, the br0 bridge joins the following
IPv6 groups due to the code path detailed below:

33:33:ff:6d:c1:9c vid 0
33:33:00:00:00:6a vid 0
33:33:00:00:00:fb vid 0

br_dev_xmit
-> br_multicast_rcv
   -> br_ip6_multicast_add_group
      -> __br_multicast_add_group
         -> br_multicast_host_join
            -> br_mdb_notify

This is all fine, but inside br_mdb_notify we have br_mdb_switchdev_host
hooked up, and switchdev will attempt to offload the host joined groups
to an empty list of ports. Of course nobody offloads them.

Then when we add a port to br0:

ip link set swp0 master br0

the bridge doesn't replay the host-joined MDB entries from br_add_if,
and eventually the host joined addresses expire, and a switchdev
notification for deleting it is emitted, but surprise, the original
addition was already completely missed.

The strategy to address this problem is to replay the MDB entries (both
the port ones and the host joined ones) when the new port joins the
bridge, similar to what vxlan_fdb_replay does (in that case, its FDB can
be populated and only then attached to a bridge that you offload).
However there are 2 possibilities: the addresses can be 'pushed' by the
bridge into the port, or the port can 'pull' them from the bridge.

Considering that in the general case, the new port can be really late to
the party, and there may have been many other switchdev ports that
already received the initial notification, we would like to avoid
delivering duplicate events to them, since they might misbehave. And
currently, the bridge calls the entire switchdev notifier chain, whereas
for replaying it should just call the notifier block of the new guy.
But the bridge doesn't know what is the new guy's notifier block, it
just knows where the switchdev notifier chain is. So for simplification,
we make this a driver-initiated pull for now, and the notifier block is
passed as an argument.

To emulate the calling context for mdb objects (deferred and put on the
blocking notifier chain), we must iterate under RCU protection through
the bridge's mdb entries, queue them, and only call them once we're out
of the RCU read-side critical section.

There was some opportunity for reuse between br_mdb_switchdev_host_port,
br_mdb_notify and the newly added br_mdb_queue_one in how the switchdev
mdb object is created, so a helper was created.

Suggested-by: Ido Schimmel 
Signed-off-by: Vladimir Oltean 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

net: bridge: add helper to retrieve the current ageing time

2021-03-23T21:49:05+00:00

The SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME attribute is only emitted from:

sysfs/ioctl/netlink
-> br_set_ageing_time
   -> __set_ageing_time

therefore not at bridge port creation time, so:
(a) switchdev drivers have to hardcode the initial value for the address
    ageing time, because they didn't get any notification
(b) that hardcoded value can be out of sync, if the user changes the
    ageing time before enslaving the port to the bridge

We need a helper in the bridge, such that switchdev drivers can query
the current value of the bridge ageing time when they start offloading
it.

Signed-off-by: Vladimir Oltean 
Reviewed-by: Florian Fainelli 
Reviewed-by: Tobias Waldekranz 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

net: bridge: add helper for retrieving the current bridge port STP state

2021-03-23T21:49:05+00:00

It may happen that we have the following topology with DSA or any other
switchdev driver with LAG offload:

ip link add br0 type bridge stp_state 1
ip link add bond0 type bond
ip link set bond0 master br0
ip link set swp0 master bond0
ip link set swp1 master bond0

STP decides that it should put bond0 into the BLOCKING state, and
that's that. The ports that are actively listening for the switchdev
port attributes emitted for the bond0 bridge port (because they are
offloading it) and have the honor of seeing that switchdev port
attribute can react to it, so we can program swp0 and swp1 into the
BLOCKING state.

But if then we do:

ip link set swp2 master bond0

then as far as the bridge is concerned, nothing has changed: it still
has one bridge port. But this new bridge port will not see any STP state
change notification and will remain FORWARDING, which is how the
standalone code leaves it in.

We need a function in the bridge driver which retrieves the current STP
state, such that drivers can synchronize to it when they may have missed
switchdev events.

Signed-off-by: Vladimir Oltean 
Reviewed-by: Florian Fainelli 
Reviewed-by: Tobias Waldekranz 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

net: bridge: mcast: add support for raw L2 multicast groups

2020-10-31T00:49:19+00:00

Extend the bridge multicast control and data path to configure routes
for L2 (non-IP) multicast groups.

The uapi struct br_mdb_entry union u is extended with another variant,
mac_addr, which does not change the structure size, and which is valid
when the proto field is zero.

To be compatible with the forwarding code that is already in place,
which acts as an IGMP/MLD snooping bridge with querier capabilities, we
need to declare that for L2 MDB entries (for which there exists no such
thing as IGMP/MLD snooping/querying), that there is always a querier.
Otherwise, these entries would be flooded to all bridge ports and not
just to those that are members of the L2 multicast group.

Needless to say, only permanent L2 multicast groups can be installed on
a bridge port.

Signed-off-by: Nikolay Aleksandrov 
Signed-off-by: Vladimir Oltean 
Link: https://lore.kernel.org/r/20201028233831.610076-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski

net: bridge: mcast: rename br_ip's u member to dst

2020-09-23T20:24:34+00:00

Since now we have src in br_ip, u no longer makes sense so rename
it to dst. No functional changes.

v2: fix build with CONFIG_BATMAN_ADV_MCAST

CC: Marek Lindner 
CC: Simon Wunderlich 
CC: Antonio Quartulli 
CC: Sven Eckelmann 
CC: b.a.t.m.a.n@lists.open-mesh.org
Signed-off-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

net: bridge: add src field to br_ip

2020-09-23T20:24:34+00:00

Add a new src field to struct br_ip which will be used to lookup S, G
entries. When SSM option is added we will enable full br_ip lookups.

Signed-off-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

bridge: mrp: Extend bridge interface

2020-07-14T20:46:42+00:00

This patch adds a new flag(BR_MRP_LOST_IN_CONT) to the net bridge
ports. This bit will be set when the port lost the continuity of
MRP_InTest frames.

Signed-off-by: Horatiu Vultur 
Acked-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

bridge: mrp: Extend bridge interface

2020-04-27T18:40:25+00:00

To integrate MRP into the bridge, first the bridge needs to be aware of ports
that are part of an MRP ring and which rings are on the bridge.
Therefore extend bridge interface with the following:
- add new flag(BR_MPP_AWARE) to the net bridge ports, this bit will be
  set when the port is added to an MRP instance. In this way it knows if
  the frame was received on MRP ring port
- add new flag(BR_MRP_LOST_CONT) to the net bridge ports, this bit will be set
  when the port lost the continuity of MRP Test frames.
- add a list of MRP instances

Reviewed-by: Nikolay Aleksandrov 
Signed-off-by: Horatiu Vultur 
Signed-off-by: David S. Miller