Flip the sign of a return value check, thereby suppressing the following
spurious error:
port 2 failed to notify DSA_NOTIFIER_BRIDGE_LEAVE: -EOPNOTSUPP
... which is emitted when removing an unoffloaded DSA switch port from a
bridge.
Fixes: d371b7c92d19 ("net: dsa: Unset vlan_filtering when ports leave the bridge")
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20211012112730.3429157-1-alvin@pqrs.dk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As explained in commit e358bef7c392 ("net: dsa: Give drivers the chance
to veto certain upper devices"), the hellcreek driver uses some tricks
to comply with the network stack expectations: it enforces port
separation in standalone mode using VLANs. For untagged traffic,
bridging between ports is prevented by using different PVIDs, and for
VLAN-tagged traffic, it never accepts 8021q uppers with the same VID on
two ports, so packets with one VLAN cannot leak from one port to another.
That is almost fine*, and has worked because hellcreek relied on an
implicit behavior of the DSA core that was changed by the previous
patch: the standalone ports declare the 'rx-vlan-filter' feature as 'on
[fixed]'. Since most of the DSA drivers are actually VLAN-unaware in
standalone mode, that feature was actually incorrectly reflecting the
hardware/driver state, so there was a desire to fix it. This leaves the
hellcreek driver in a situation where it has to explicitly request this
behavior from the DSA framework.
We configure the ports as follows:
- Standalone: 'rx-vlan-filter' is on. An 8021q upper on top of a
standalone hellcreek port will go through dsa_slave_vlan_rx_add_vid
and will add a VLAN to the hardware tables, giving the driver the
opportunity to refuse it through .port_prechangeupper.
- Bridged with vlan_filtering=0: 'rx-vlan-filter' is off. An 8021q upper
on top of a bridged hellcreek port will not go through
dsa_slave_vlan_rx_add_vid, because there will not be any attempt to
offload this VLAN. The driver already disables VLAN awareness, so that
upper should receive the traffic it needs.
- Bridged with vlan_filtering=1: 'rx-vlan-filter' is on. An 8021q upper
on top of a bridged hellcreek port will call dsa_slave_vlan_rx_add_vid,
and can again be vetoed through .port_prechangeupper.
*It is not actually completely fine, because if I follow through
correctly, we can have the following situation:
ip link add br0 type bridge vlan_filtering 0
ip link set lan0 master br0 # lan0 now becomes VLAN-unaware
ip link set lan0 nomaster # lan0 fails to become VLAN-aware again, therefore breaking isolation
This patch fixes that corner case by extending the DSA core logic, based
on this requested attribute, to change the VLAN awareness state of the
switch (port) when it leaves the bridge.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
If the driver does not implement .port_bridge_{join,leave}, then we must
fall back to standalone operation on that port, and trigger the error
path of dsa_port_bridge_join. This sets dp->bridge_dev = NULL.
In turn, having a non-NULL dp->bridge_dev when there is no offloading
support makes the following things go wrong:
- dsa_default_offload_fwd_mark make the wrong decision in setting
skb->offload_fwd_mark. It should set skb->offload_fwd_mark = 0 for
ports that don't offload the bridge, which should instruct the bridge
to forward in software. But this does not happen, dp->bridge_dev is
incorrectly set to point to the bridge, so the bridge is told that
packets have been forwarded in hardware, which they haven't.
- switchdev objects (MDBs, VLANs) should not be offloaded by ports that
don't offload the bridge. Standalone ports should behave as packet-in,
packet-out and the bridge should not be able to manipulate the pvid of
the port, or tag stripping on egress, or ingress filtering. This
should already work fine because dsa_slave_port_obj_add has:
case SWITCHDEV_OBJ_ID_PORT_VLAN:
if (!dsa_port_offloads_bridge_port(dp, obj->orig_dev))
return -EOPNOTSUPP;
err = dsa_slave_vlan_add(dev, obj, extack);
but since dsa_port_offloads_bridge_port works based on dp->bridge_dev,
this is again sabotaging us.
All the above work in case the port has an unoffloaded LAG interface, so
this is well exercised code, we should apply it for plain unoffloaded
bridge ports too.
Reported-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The big problem which mandates cross-chip notifiers for tag_8021q is
this:
|
sw0p0 sw0p1 sw0p2 sw0p3 sw0p4
[ user ] [ user ] [ user ] [ dsa ] [ cpu ]
|
+---------+
|
sw1p0 sw1p1 sw1p2 sw1p3 sw1p4
[ user ] [ user ] [ user ] [ dsa ] [ dsa ]
|
+---------+
|
sw2p0 sw2p1 sw2p2 sw2p3 sw2p4
[ user ] [ user ] [ user ] [ dsa ] [ dsa ]
When the user runs:
ip link add br0 type bridge
ip link set sw0p0 master br0
ip link set sw2p0 master br0
It doesn't work.
This is because dsa_8021q_crosschip_bridge_join() assumes that "ds" and
"other_ds" are at most 1 hop away from each other, so it is sufficient
to add the RX VLAN of {ds, port} into {other_ds, other_port} and vice
versa and presto, the cross-chip link works. When there is another
switch in the middle, such as in this case switch 1 with its DSA links
sw1p3 and sw1p4, somebody needs to tell it about these VLANs too.
Which is exactly why the problem is quadratic: when a port joins a
bridge, for each port in the tree that's already in that same bridge we
notify a tag_8021q VLAN addition of that port's RX VLAN to the entire
tree. It is a very complicated web of VLANs.
It must be mentioned that currently we install tag_8021q VLANs on too
many ports (DSA links - to be precise, on all of them). For example,
when sw2p0 joins br0, and assuming sw1p0 was part of br0 too, we add the
RX VLAN of sw2p0 on the DSA links of switch 0 too, even though there
isn't any port of switch 0 that is a member of br0 (at least yet).
In theory we could notify only the switches which sit in between the
port joining the bridge and the port reacting to that bridge_join event.
But in practice that is impossible, because of the way 'link' properties
are described in the device tree. The DSA bindings require DT writers to
list out not only the real/physical DSA links, but in fact the entire
routing table, like for example switch 0 above will have:
sw0p3: port@3 {
link = <&sw1p4 &sw2p4>;
};
This was done because:
/* TODO: ideally DSA ports would have a single dp->link_dp member,
* and no dst->rtable nor this struct dsa_link would be needed,
* but this would require some more complex tree walking,
* so keep it stupid at the moment and list them all.
*/
but it is a perfect example of a situation where too much information is
actively detrimential, because we are now in the position where we
cannot distinguish a real DSA link from one that is put there to avoid
the 'complex tree walking'. And because DT is ABI, there is not much we
can change.
And because we do not know which DSA links are real and which ones
aren't, we can't really know if DSA switch A is in the data path between
switches B and C, in the general case.
So this is why tag_8021q RX VLANs are added on all DSA links, and
probably why it will never change.
On the other hand, at least the number of additions/deletions is well
balanced, and this means that once we implement reference counting at
the cross-chip notifier level a la fdb/mdb, there is absolutely zero
need for a struct dsa_8021q_crosschip_link, it's all self-managing.
In fact, with the tag_8021q notifiers emitted from the bridge join
notifiers, it becomes so generic that sja1105 does not need to do
anything anymore, we can just delete its implementation of the
.crosschip_bridge_{join,leave} methods.
Among other things we can simply delete is the home-grown implementation
of sja1105_notify_crosschip_switches(). The reason why that is wrong is
because it is not quadratic - it only covers remote switches to which we
have a cross-chip bridging link and that does not cover in-between
switches. This deletion is part of the same patch because sja1105 used
to poke deep inside the guts of the tag_8021q context in order to do
that. Because the cross-chip links went away, so needs the sja1105 code.
Last but not least, dsa_8021q_setup_port() is simplified (and also
renamed). Because our TAG_8021Q_VLAN_ADD notifier is designed to react
on the CPU port too, the four dsa_8021q_vid_apply() calls:
- 1 for RX VLAN on user port
- 1 for the user port's RX VLAN on the CPU port
- 1 for TX VLAN on user port
- 1 for the user port's TX VLAN on the CPU port
now get squashed into only 2 notifier calls via
dsa_port_tag_8021q_vlan_add.
And because the notifiers to add and to delete a tag_8021q VLAN are
distinct, now we finally break up the port setup and teardown into
separate functions instead of relying on a "bool enabled" flag which
tells us what to do. Arguably it should have been this way from the
get go.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There has been at least one wasted opportunity for tag_8021q to be used
by a driver:
https://patchwork.ozlabs.org/project/netdev/patch/20200710113611.3398-3-kurt@linutronix.de/#2484272
because of a design decision: the declared purpose of tag_8021q is to
offer source port/switch identification for a tagging driver for packets
coming from a switch with no hardware DSA tagging support. It is not
intended to provide VLAN-based port isolation, because its first user,
sja1105, had another mechanism for bridging domain isolation, the L2
Forwarding Table. So even if 2 ports are in the same VLAN but they are
separated via the L2 Forwarding Table, they will not communicate with
one another. The L2 Forwarding Table is managed by the
sja1105_bridge_join() and sja1105_bridge_leave() methods.
As a consequence, today tag_8021q does not bother too much with hooking
into .port_bridge_join() and .port_bridge_leave() because that would
introduce yet another degree of freedom, it just iterates statically
through all ports of a switch and adds the RX VLAN of one port to all
the others. In this way, whenever .port_bridge_join() is called,
bridging will magically work because the RX VLANs are already installed
everywhere they need to be.
This is not to say that the reason for the change in this patch is to
satisfy the hellcreek and similar use cases, that is merely a nice side
effect. Instead it is to make sja1105 cross-chip links work properly
over a DSA link.
For context, sja1105 today supports a degenerate form of cross-chip
bridging, where the switches are interconnected through their CPU ports
("disjoint trees" topology). There is some code which has been
generalized into dsa_8021q_crosschip_link_{add,del}, but it is not
enough, and frankly it is impossible to build upon that.
Real multi-switch DSA trees, like daisy chains or H trees, which have
actual DSA links, do not work.
The problem is that sja1105 is unlike mv88e6xxx, and does not have a PVT
for cross-chip bridging, which is a table by which the local switch can
select the forwarding domain for packets from a certain ingress switch
ID and source port. The sja1105 switches cannot parse their own DSA
tags, because, well, they don't really have support for DSA tags, it's
all VLANs.
So to make something like cross-chip bridging between sw0p0 and sw1p0 to
work over the sw0p3/sw1p3 DSA link to work with sja1105 in the topology
below:
| |
sw0p0 sw0p1 sw0p2 sw0p3 sw1p3 sw1p2 sw1p1 sw1p0
[ user ] [ user ] [ cpu ] [ dsa ] ---- [ dsa ] [ cpu ] [ user ] [ user ]
we need to ask ourselves 2 questions:
(1) how should the L2 Forwarding Table be managed?
(2) how should the VLAN Lookup Table be managed?
i.e. what should prevent packets from going to unwanted ports?
Since as mentioned, there is no PVT, the L2 Forwarding Table only
contains forwarding rules for local ports. So we can say "all user ports
are allowed to forward to all CPU ports and all DSA links".
If we allow forwarding to DSA links unconditionally, this means we must
prevent forwarding using the VLAN Lookup Table. This is in fact
asymmetric with what we do for tag_8021q on ports local to the same
switch, and it matters because now that we are making tag_8021q a core
DSA feature, we need to hook into .crosschip_bridge_join() to add/remove
the tag_8021q VLANs. So for symmetry it makes sense to manage the VLANs
for local forwarding in the same way as cross-chip forwarding.
Note that there is a very precise reason why tag_8021q hooks into
dsa_switch_bridge_join() which acts at the cross-chip notifier level,
and not at a higher level such as dsa_port_bridge_join(). We need to
install the RX VLAN of the newly joining port into the VLAN table of all
the existing ports across the tree that are part of the same bridge, and
the notifier already does the iteration through the switches for us.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This was not caught because there is no switch driver which implements
the .port_bridge_join but not .port_bridge_leave method, but it should
nonetheless be fixed, as in certain conditions (driver development) it
might lead to NULL pointer dereference.
Fixes: f66a6a69f97a ("net: dsa: permit cross-chip bridging between all trees in the system")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The DSA core has a layered structure, and even though we end up returning 0 (success) to user space when setting a bonding/team upper that can't be offloaded, some parts of the framework actually need to know that we couldn't offload that. For example, if dsa_switch_lag_join returns 0 as it currently does, dsa_port_lag_join has no way to tell a successful offload from a software fallback, and it will call dsa_port_bridge_join afterwards. Then we'll think we're offloading the bridge master of the LAG, when in fact we're not even offloading the LAG. In turn, this will make us set skb->offload_fwd_mark = true, which is incorrect and the bridge doesn't like it. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
The same concerns expressed for host MDB entries are valid for host FDBs just as well: - in the case of multiple bridges spanning the same switch chip, deleting a host FDB entry that belongs to one bridge will result in breakage to the other bridge - not deleting FDB entries across DSA links means that the switch's hardware tables will eventually run out, given enough wear&tear So do the same thing and introduce reference counting for CPU ports and DSA links using the same data structures as we have for MDB entries. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
DSA treats some bridge FDB entries by trapping them to the CPU port. Currently, the only class of such entries are FDB addresses learnt by the software bridge on a foreign interface. However there are many more to be added: - FDB entries with the is_local flag (for termination) added by the bridge on the user ports (typically containing the MAC address of the bridge port) - FDB entries pointing towards the bridge net device (for termination). Typically these contain the MAC address of the bridge net device. - Static FDB entries installed on a foreign interface that is in the same bridge with a DSA user port. The reason why a separate cross-chip notifier for host FDBs is justified compared to normal FDBs is the same as in the case of host MDBs: the cross-chip notifier matching function in switch.c should avoid installing these entries on routing ports that route towards the targeted switch, but not towards the CPU. This is required in order to have proper support for H-like multi-chip topologies. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Ever since the cross-chip notifiers were introduced, the design was
meant to be simplistic and just get the job done without worrying too
much about dangling resources left behind.
For example, somebody installs an MDB entry on sw0p0 in this daisy chain
topology. It gets installed using ds->ops->port_mdb_add() on sw0p0,
sw1p4 and sw2p4.
|
sw0p0 sw0p1 sw0p2 sw0p3 sw0p4
[ user ] [ user ] [ user ] [ dsa ] [ cpu ]
[ x ] [ ] [ ] [ ] [ ]
|
+---------+
|
sw1p0 sw1p1 sw1p2 sw1p3 sw1p4
[ user ] [ user ] [ user ] [ dsa ] [ dsa ]
[ ] [ ] [ ] [ ] [ x ]
|
+---------+
|
sw2p0 sw2p1 sw2p2 sw2p3 sw2p4
[ user ] [ user ] [ user ] [ user ] [ dsa ]
[ ] [ ] [ ] [ ] [ x ]
Then the same person deletes that MDB entry. The cross-chip notifier for
deletion only matches sw0p0:
|
sw0p0 sw0p1 sw0p2 sw0p3 sw0p4
[ user ] [ user ] [ user ] [ dsa ] [ cpu ]
[ x ] [ ] [ ] [ ] [ ]
|
+---------+
|
sw1p0 sw1p1 sw1p2 sw1p3 sw1p4
[ user ] [ user ] [ user ] [ dsa ] [ dsa ]
[ ] [ ] [ ] [ ] [ ]
|
+---------+
|
sw2p0 sw2p1 sw2p2 sw2p3 sw2p4
[ user ] [ user ] [ user ] [ user ] [ dsa ]
[ ] [ ] [ ] [ ] [ ]
Why?
Because the DSA links are 'trunk' ports, if we just go ahead and delete
the MDB from sw1p4 and sw2p4 directly, we might delete those multicast
entries when they are still needed. Just consider the fact that somebody
does:
- add a multicast MAC address towards sw0p0 [ via the cross-chip
notifiers it gets installed on the DSA links too ]
- add the same multicast MAC address towards sw0p1 (another port of that
same switch)
- delete the same multicast MAC address from sw0p0.
At this point, if we deleted the MAC address from the DSA links, it
would be flooded, even though there is still an entry on switch 0 which
needs it not to.
So that is why deletions only match the targeted source port and nothing
on DSA links. Of course, dangling resources means that the hardware
tables will eventually run out given enough additions/removals, but hey,
at least it's simple.
But there is a bigger concern which needs to be addressed, and that is
our support for SWITCHDEV_OBJ_ID_HOST_MDB. DSA simply translates such an
object into a dsa_port_host_mdb_add() which ends up as ds->ops->port_mdb_add()
on the upstream port, and a similar thing happens on deletion:
dsa_port_host_mdb_del() will trigger ds->ops->port_mdb_del() on the
upstream port.
When there are 2 VLAN-unaware bridges spanning the same switch (which is
a use case DSA proudly supports), each bridge will install its own
SWITCHDEV_OBJ_ID_HOST_MDB entries. But upon deletion, DSA goes ahead and
emits a DSA_NOTIFIER_MDB_DEL for dp->cpu_dp, which is shared between the
user ports enslaved to br0 and the user ports enslaved to br1. Not good.
The host-trapped multicast addresses installed by br1 will be deleted
when any state changes in br0 (IGMP timers expire, or ports leave, etc).
To avoid this, we could of course go the route of the zero-sum game and
delete the DSA_NOTIFIER_MDB_DEL call for dp->cpu_dp. But the better
design is to just admit that on shared ports like DSA links and CPU
ports, we should be reference counting calls, even if this consumes some
dynamic memory which DSA has traditionally avoided. On the flip side,
the hardware tables of switches are limited in size, so it would be good
if the OS managed them properly instead of having them eventually
overflow.
To address the memory usage concern, we only apply the refcounting of
MDB entries on ports that are really shared (CPU ports and DSA links)
and not on user ports. In a typical single-switch setup, this means only
the CPU port (and the host MDB entries are not that many, really).
The name of the newly introduced data structures (dsa_mac_addr) is
chosen in such a way that will be reusable for host FDB entries (next
patch).
With this change, we can finally have the same matching logic for the
MDB additions and deletions, as well as for their host-trapped variants.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>