net: bridge: switchdev: Ensure deferred event delivery on unoffload

When unoffloading a device, it is important to ensure that all
relevant deferred events are delivered to it before it disassociates
itself from the bridge.

Before this change, this was true for the normal case when a device
maps 1:1 to a net_bridge_port, i.e.

br0
/
swp0

When swp0 leaves br0, the call to switchdev_deferred_process() in
del_nbp() makes sure to process any outstanding events while the
device is still associated with the bridge.

In the case when the association is indirect though, i.e. when the
device is attached to the bridge via an intermediate device, like a
LAG...

br0
/
lag0
/
swp0

...then detaching swp0 from lag0 does not cause any net_bridge_port to
be deleted, so there was no guarantee that all events had been
processed before the device disassociated itself from the bridge.

Fix this by always synchronously processing all deferred events before
signaling completion of unoffloading back to the driver.

Fixes: 4e51bf44a03a ("net: bridge: move the switchdev object replay helpers to "push" mode")
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: Skip MDB replays of deferred events on offload

Before this change, generation of the list of MDB events to replay
would race against the creation of new group memberships, either from
the IGMP/MLD snooping logic or from user configuration.

While new memberships are immediately visible to walkers of
br->mdb_list, the notification of their existence to switchdev event
subscribers is deferred until a later point in time. So if a replay
list was generated during a time that overlapped with such a window,
it would also contain a replay of the not-yet-delivered event.

The driver would thus receive two copies of what the bridge internally
considered to be one single event. On destruction of the bridge, only
a single membership deletion event was therefore sent. As a
consequence of this, drivers which reference count memberships (at
least DSA), would be left with orphan groups in their hardware
database when the bridge was destroyed.

This is only an issue when replaying additions. While deletion events
may still be pending on the deferred queue, they will already have
been removed from br->mdb_list, so no duplicates can be generated in
that scenario.

To a user this meant that old group memberships, from a bridge in
which a port was previously attached, could be reanimated (in
hardware) when the port joined a new bridge, without the new bridge's
knowledge.

For example, on an mv88e6xxx system, create a snooping bridge and
immediately add a port to it:

root@infix-06-0b-00:~$ ip link add dev br0 up type bridge mcast_snooping 1 && \
> ip link set dev x3 up master br0

And then destroy the bridge:

root@infix-06-0b-00:~$ ip link del dev br0
root@infix-06-0b-00:~$ mvls atu
ADDRESS FID STATE Q F 0 1 2 3 4 5 6 7 8 9 a
DEV:0 Marvell 88E6393X
33:33:00:00:00:6a 1 static - - 0 . . . . . . . . . .
33:33:ff:87:e4:3f 1 static - - 0 . . . . . . . . . .
ff:ff:ff:ff:ff:ff 1 static - - 0 1 2 3 4 5 6 7 8 9 a
root@infix-06-0b-00:~$

The two IPv6 groups remain in the hardware database because the
port (x3) is notified of the host's membership twice: once via the
original event and once via a replay. Since only a single delete
notification is sent, the count remains at 1 when the bridge is
destroyed.

Then add the same port (or another port belonging to the same hardware
domain) to a new bridge, this time with snooping disabled:

root@infix-06-0b-00:~$ ip link add dev br1 up type bridge mcast_snooping 0 && \
> ip link set dev x3 up master br1

All multicast, including the two IPv6 groups from br0, should now be
flooded, according to the policy of br1. But instead the old
memberships are still active in the hardware database, causing the
switch to only forward traffic to those groups towards the CPU (port
0).

Eliminate the race in two steps:

1. Grab the write-side lock of the MDB while generating the replay
list.

This prevents new memberships from showing up while we are generating
the replay list. But it leaves the scenario in which a deferred event
was already generated, but not delivered, before we grabbed the
lock. Therefore:

2. Make sure that no deferred version of a replay event is already
enqueued to the switchdev deferred queue, before adding it to the
replay list, when replaying additions.

Fixes: 4f2673b3a2b6 ("net: bridge: add helper to replay port and host-joined mdb entries")
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: switchdev: Add a helper to replay objects on a bridge port

When a front panel joins a bridge via another netdevice (typically a LAG),
the driver needs to learn about the objects configured on the bridge port.
When the bridge port is offloaded by the driver for the first time, this
can be achieved by passing a notifier to switchdev_bridge_port_offload().
The notifier is then invoked for the individual objects (such as VLANs)
configured on the bridge, and can look for the interesting ones.

Calling switchdev_bridge_port_offload() when the second port joins the
bridge lower is unnecessary, but the replay is still needed. To that end,
add a new function, switchdev_bridge_port_replay(), which does only the
replay part of the _offload() function in exactly the same way as that
function.

Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Ivan Vecera <ivecera@redhat.com>
Cc: Roopa Prabhu <roopa@nvidia.com>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
Cc: bridge@lists.linux-foundation.org
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: br_switchdev: Tolerate -EOPNOTSUPP when replaying MDB

There are two kinds of MDB entries to be replayed: port MDB entries, and
host MDB entries. They are both replayed by br_switchdev_mdb_replay(). If
the driver supports one kind, but lacks the other, the first -EOPNOTSUPP
returned terminates the whole replay, including any further still-supported
objects in the list.

For this to cause issues, there must be MDB entries for both the host and
the port being replayed. In that case, if the driver bails out from
handling the host entry, the port entries are never replayed. However, the
replay is currently only done when a switchdev port joins a bridge. There
would be no port memberships at that point. Thus despite being erroneous,
the code does not cause observable bugs.

This is not an issue with other object kinds either, because there, each
function replays one object kind. If a driver does not support that kind,
it makes sense to bail out early. -EOPNOTSUPP is then ignored in
nbp_switchdev_sync_objs().

For MDB, suppress the -EOPNOTSUPP error code in br_switchdev_mdb_replay()
already, so that the whole list gets replayed.

The reason we need this patch is that a future patch will introduce a
replay that should be used when a front-panel port netdevice is enslaved to
a bridge lower, in particular a LAG. The LAG netdevice can already have
both host and port MDB entries. The port entries need to be replayed so
that they are offloaded on the port that joins the LAG.

Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Ivan Vecera <ivecera@redhat.com>
Cc: Roopa Prabhu <roopa@nvidia.com>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
Cc: bridge@lists.linux-foundation.org
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: don't notify FDB entries with "master dynamic"

There is a structural problem in switchdev, where the flag bits in
struct switchdev_notifier_fdb_info (added_by_user, is_local etc) only
represent a simplified / denatured view of what's in struct
net_bridge_fdb_entry :: flags (BR_FDB_ADDED_BY_USER, BR_FDB_LOCAL etc).
Each time we want to pass more information about struct
net_bridge_fdb_entry :: flags to struct switchdev_notifier_fdb_info
(here, BR_FDB_STATIC), we find that FDB entries were already notified to
switchdev with no regard to this flag, and thus, switchdev drivers had
no indication whether the notified entries were static or not.

For example, this command:

ip link add br0 type bridge && ip link set swp0 master br0
bridge fdb add dev swp0 00:01:02:03:04:05 master dynamic

has never worked as intended with switchdev. It causes a struct
net_bridge_fdb_entry to be passed to br_switchdev_fdb_notify() which has
a single flag set: BR_FDB_ADDED_BY_USER.

This is further passed to the switchdev notifier chain, where interested
drivers have no choice but to assume this is a static (does not age) and
sticky (does not migrate) FDB entry. So currently, all drivers offload
it to hardware as such, as can be seen below ("offload" is set).

bridge fdb get 00:01:02:03:04:05 dev swp0 master
00:01:02:03:04:05 dev swp0 offload master br0

The software FDB entry expires $ageing_time centiseconds after the
kernel last sees a packet with this MAC SA, and the bridge notifies its
deletion as well, so it eventually disappears from hardware too.

This is a problem, because it is actually desirable to start offloading
"master dynamic" FDB entries correctly - they should expire $ageing_time
centiseconds after the *hardware* port last sees a packet with this
MAC SA - and this is how the current incorrect behavior was discovered.
With an offloaded data plane, it can be expected that software only sees
exception path packets, so an otherwise active dynamic FDB entry would
be aged out by software sooner than it should.

With the change in place, these FDB entries are no longer offloaded:

bridge fdb get 00:01:02:03:04:05 dev swp0 master
00:01:02:03:04:05 dev swp0 master br0

and this also constitutes a better way (assuming a backport to stable
kernels) for user space to determine whether the kernel has the
capability of doing something sane with these or not.

As opposed to "master dynamic" FDB entries, on the current behavior of
which no one currently depends on (which can be deduced from the lack of
kselftests), Ido Schimmel explains that entries with the "extern_learn"
flag (BR_FDB_ADDED_BY_EXT_LEARN) should still be notified to switchdev,
since the spectrum driver listens to them (and this is kind of okay,
because although they are treated identically to "static", they are
expected to not age, and to roam).

Fixes: 6b26b51b1d13 ("net: bridge: Add support for notifying devices about FDB add/del")
Link: https://lore.kernel.org/netdev/20230327115206.jk5q5l753aoelwus@skbuf/
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20230418155902.898627-1-vladimir.oltean@nxp.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

netlink: provide an ability to set default extack message

In netdev common pattern, extack pointer is forwarded to the drivers
to be filled with error message. However, the caller can easily
overwrite the filled message.

Instead of adding multiple "if (!extack->_msg)" checks before any
NL_SET_ERR_MSG() call, which appears after call to the driver, let's
add new macro to common code.

[1] https://lore.kernel.org/all/Y9Irgrgf3uxOjwUm@unreal
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/6993fac557a40a1973dfa0095107c3d03d40bec1.1675171790.git.leon@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

bridge: switchdev: Reflect MAB bridge port flag to device drivers

Reflect the 'BR_PORT_MAB' flag to device drivers so that:

* Drivers that support MAB could act upon the flag being toggled.
* Drivers that do not support MAB will prevent MAB from being enabled.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

bridge: switchdev: Allow device drivers to install locked FDB entries

When the bridge is offloaded to hardware, FDB entries are learned and
aged-out by the hardware. Some device drivers synchronize the hardware
and software FDBs by generating switchdev events towards the bridge.

When a port is locked, the hardware must not learn autonomously, as
otherwise any host will blindly gain authorization. Instead, the
hardware should generate events regarding hosts that are trying to gain
authorization and their MAC addresses should be notified by the device
driver as locked FDB entries towards the bridge driver.

Allow device drivers to notify the bridge driver about such entries by
extending the 'switchdev_notifier_fdb_info' structure with the 'locked'
bit. The bit can only be set by device drivers and not by the bridge
driver.

Prevent a locked entry from being installed if MAB is not enabled on the
bridge port.

If an entry already exists in the bridge driver, reject the locked entry
if the current entry does not have the "locked" flag set or if it points
to a different port. The same semantics are implemented in the software
data path.

Signed-off-by: Hans J. Schultz <netdev@kapio-technology.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: bridge: offload BR_HAIRPIN_MODE, BR_ISOLATED, BR_MULTICAST_TO_UNICAST

Add BR_HAIRPIN_MODE, BR_ISOLATED and BR_MULTICAST_TO_UNICAST port flags to
BR_PORT_FLAGS_HW_OFFLOAD so that switchdev drivers which have an offloaded
data plane have a chance to reject these bridge port flags if they don't
support them yet.

It makes the code path go through the
SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS driver handlers, which return
-EINVAL for everything they don't recognize.

For drivers that don't catch SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS at
all, switchdev will return -EOPNOTSUPP for those which is then ignored, but
those are in the minority.

Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20220410134227.18810-1-arinc.unal@arinc9.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: bridge: switchdev: check br_vlan_group() return value

br_vlan_group() can return NULL and thus return value must be checked
to avoid dereferencing a NULL pointer.

Fixes: 6284c723d9b9 ("net: bridge: mst: Notify switchdev drivers of VLAN MSTI migrations")
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20220421101247.121896-1-clement.leger@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: bridge: mst: Notify switchdev drivers of VLAN MSTI migrations

Whenever a VLAN moves to a new MSTI, send a switchdev notification so
that switchdevs can track a bridge's VID to MSTI mappings.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: bridge: Add support for offloading of locked port flag

Various switchcores support setting ports in locked mode, so that
clients behind locked ports cannot send traffic through the port
unless a fdb entry is added with the clients MAC address.

Signed-off-by: Hans Schultz <schultz.hans+netdev@gmail.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: replay all VLAN groups

The major user of replayed switchdev objects is DSA, and so far it
hasn't needed information about anything other than bridge port VLANs,
so this is all that br_switchdev_vlan_replay() knows to handle.

DSA has managed to get by through replicating every VLAN addition on a
user port such that the same VLAN is also added on all DSA and CPU
ports, but there is a corner case where this does not work.

The mv88e6xxx DSA driver currently prints this error message as soon as
the first port of a switch joins a bridge:

mv88e6085 0x0000000008b96000:00: port 0 failed to add a6:ef:77:c8:5f:3d vid 1 to fdb: -95

where a6:ef:77:c8:5f:3d vid 1 is a local FDB entry corresponding to the
bridge MAC address in the default_pvid.

The -EOPNOTSUPP is returned by mv88e6xxx_port_db_load_purge() because it
tries to map VID 1 to a FID (the ATU is indexed by FID not VID), but
fails to do so. This is because ->port_fdb_add() is called before
->port_vlan_add() for VID 1.

The abridged timeline of the calls is:

br_add_if
-> netdev_master_upper_dev_link
-> dsa_port_bridge_join
-> switchdev_bridge_port_offload
-> br_switchdev_vlan_replay (*)
-> br_switchdev_fdb_replay
-> mv88e6xxx_port_fdb_add
-> nbp_vlan_init
-> nbp_vlan_add
-> mv88e6xxx_port_vlan_add

and the issue is that at the time of (*), the bridge port isn't in VID 1
(nbp_vlan_init hasn't been called), therefore br_switchdev_vlan_replay()
won't have anything to replay, therefore VID 1 won't be in the VTU by
the time mv88e6xxx_port_fdb_add() is called.

This happens only when the first port of a switch joins. For further
ports, the initial mv88e6xxx_port_vlan_add() is sufficient for VID 1 to
be loaded in the VTU (which is switch-wide, not per port).

The problem is somewhat unique to mv88e6xxx by chance, because most
other drivers offload an FDB entry by VID, so FDBs and VLANs can be
added asynchronously with respect to each other, but addressing the
issue at the bridge layer makes sense, since what mv88e6xxx requires
isn't absurd.

To fix this problem, we need to recognize that it isn't the VLAN group
of the port that we're interested in, but the VLAN group of the bridge
itself (so it isn't a timing issue, but rather insufficient information
being passed from switchdev to drivers).

As mentioned, currently nbp_switchdev_sync_objs() only calls
br_switchdev_vlan_replay() for VLANs corresponding to the port, but the
VLANs corresponding to the bridge itself, for local termination, also
need to be replayed. In this case, VID 1 is not (yet) present in the
port's VLAN group but is present in the bridge's VLAN group.

So to fix this bug, DSA is now obligated to explicitly handle VLANs
pointing towards the bridge in order to "close this race" (which isn't
really a race). As Tobias Waldekranz notices, this also implies that it
must explicitly handle port VLANs on foreign interfaces, something that
worked implicitly before:
https://patchwork.kernel.org/project/netdevbpf/patch/20220209213044.2353153-6-vladimir.oltean@nxp.com/#24735260

So in the end, br_switchdev_vlan_replay() must replay all VLANs from all
VLAN groups: all the ports, and the bridge itself.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: make nbp_switchdev_unsync_objs() follow reverse order of sync()

There may be switchdev drivers that can add/remove a FDB or MDB entry
only as long as the VLAN it's in has been notified and offloaded first.
The nbp_switchdev_sync_objs() method satisfies this requirement on
addition, but nbp_switchdev_unsync_objs() first deletes VLANs, then
deletes MDBs and FDBs. Reverse the order of the function calls to cater
to this requirement.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: differentiate new VLANs from changed ones

br_switchdev_port_vlan_add() currently emits a SWITCHDEV_PORT_OBJ_ADD
event with a SWITCHDEV_OBJ_ID_PORT_VLAN for 2 distinct cases:

- a struct net_bridge_vlan got created
- an existing struct net_bridge_vlan was modified

This makes it impossible for switchdev drivers to properly balance
PORT_OBJ_ADD with PORT_OBJ_DEL events, so if we want to allow that to
happen, we must provide a way for drivers to distinguish between a
VLAN with changed flags and a new one.

Annotate struct switchdev_obj_port_vlan with a "bool changed" that
distinguishes the 2 cases above.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: consistent function naming

Rename all recently imported functions in br_switchdev.c to start with a
br_switchdev_* prefix.

br_fdb_replay_one() -> br_switchdev_fdb_replay_one()
br_fdb_replay() -> br_switchdev_fdb_replay()
br_vlan_replay_one() -> br_switchdev_vlan_replay_one()
br_vlan_replay() -> br_switchdev_vlan_replay()
struct br_mdb_complete_info -> struct br_switchdev_mdb_complete_info
br_mdb_complete() -> br_switchdev_mdb_complete()
br_mdb_switchdev_host_port() -> br_switchdev_host_mdb_one()
br_mdb_switchdev_host() -> br_switchdev_host_mdb()
br_mdb_replay_one() -> br_switchdev_mdb_replay_one()
br_mdb_replay() -> br_switchdev_mdb_replay()
br_mdb_queue_one() -> br_switchdev_mdb_queue_one()

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: bridge: mdb: move all switchdev logic to br_switchdev.c

The following functions:

br_mdb_complete
br_switchdev_mdb_populate
br_mdb_replay_one
br_mdb_queue_one
br_mdb_replay
br_mdb_switchdev_host_port
br_mdb_switchdev_host
br_switchdev_mdb_notify

are only accessible from code paths where CONFIG_NET_SWITCHDEV is
enabled. So move them to br_switchdev.c, in order for that code to be
compiled out if that config option is disabled.

Note that br_switchdev.c gets build regardless of whether
CONFIG_BRIDGE_IGMP_SNOOPING is enabled or not, whereas br_mdb.c only got
built when CONFIG_BRIDGE_IGMP_SNOOPING was enabled. So to preserve
correct compilation with CONFIG_BRIDGE_IGMP_SNOOPING being disabled, we
must now place an #ifdef around these functions in br_switchdev.c.
The offending bridge data structures that need this are
br->multicast_lock and br->mdb_list, these are also compiled out of
struct net_bridge when CONFIG_BRIDGE_IGMP_SNOOPING is turned off.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: bridge: move br_vlan_replay to br_switchdev.c

br_vlan_replay() is relevant only if CONFIG_NET_SWITCHDEV is enabled, so
move it to br_switchdev.c.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: bridge: create a common function for populating switchdev FDB entries

There are two places where a switchdev FDB entry is constructed, one is
br_switchdev_fdb_notify() and the other is br_fdb_replay(). One uses a
struct initializer, and the other declares the structure as
uninitialized and populates the elements one by one.

One problem when introducing new members of struct
switchdev_notifier_fdb_info is that there is a risk for one of these
functions to run with an uninitialized value.

So centralize the logic of populating such structure into a dedicated
function. Being the primary location where these structures are created,
using an uninitialized variable and populating the members one by one
should be fine, since this one function is supposed to assign values to
all its members.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: move br_fdb_replay inside br_switchdev.c

br_fdb_replay is only called from switchdev code paths, so it makes
sense to be disabled if switchdev is not enabled in the first place.

As opposed to br_mdb_replay and br_vlan_replay which might be turned off
depending on bridge support for multicast and VLANs, FDB support is
always on. So moving br_mdb_replay and br_vlan_replay inside
br_switchdev.c would mean adding some #ifdef's in br_switchdev.c, so we
keep those where they are.

The reason for the movement is that in future changes there will be some
code reuse between br_switchdev_fdb_notify and br_fdb_replay.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: make switchdev_bridge_port_{,unoffload} loosely coupled with the bridge

With the introduction of explicit offloading API in switchdev in commit
2f5dc00f7a3e ("net: bridge: switchdev: let drivers inform which bridge
ports are offloaded"), we started having Ethernet switch drivers calling
directly into a function exported by net/bridge/br_switchdev.c, which is
a function exported by the bridge driver.

This means that drivers that did not have an explicit dependency on the
bridge before, like cpsw and am65-cpsw, now do - otherwise it is not
possible to call a symbol exported by a driver that can be built as
module unless you are a module too.

There was an attempt to solve the dependency issue in the form of commit
b0e81817629a ("net: build all switchdev drivers as modules when the
bridge is a module"). Grygorii Strashko, however, says about it:

| In my opinion, the problem is a bit bigger here than just fixing the
| build :(
|
| In case, of ^cpsw the switchdev mode is kinda optional and in many
| cases (especially for testing purposes, NFS) the multi-mac mode is
| still preferable mode.
|
| There were no such tight dependency between switchdev drivers and
| bridge core before and switchdev serviced as independent, notification
| based layer between them, so ^cpsw still can be "Y" and bridge can be
| "M". Now for mostly every kernel build configuration the CONFIG_BRIDGE
| will need to be set as "Y", or we will have to update drivers to
| support build with BRIDGE=n and maintain separate builds for
| networking vs non-networking testing. But is this enough? Wouldn't
| it cause 'chain reaction' required to add more and more "Y" options
| (like CONFIG_VLAN_8021Q)?
|
| PS. Just to be sure we on the same page - ARM builds will be forced
| (with this patch) to have CONFIG_TI_CPSW_SWITCHDEV=m and so all our
| automation testing will just fail with omap2plus_defconfig.

In the light of this, it would be desirable for some configurations to
avoid dependencies between switchdev drivers and the bridge, and have
the switchdev mode as completely optional within the driver.

Arnd Bergmann also tried to write a patch which better expressed the
build time dependency for Ethernet switch drivers where the switchdev
support is optional, like cpsw/am65-cpsw, and this made the drivers
follow the bridge (compile as module if the bridge is a module) only if
the optional switchdev support in the driver was enabled in the first
place:
https://patchwork.kernel.org/project/netdevbpf/patch/20210802144813.1152762-1-arnd@kernel.org/

but this still did not solve the fact that cpsw and am65-cpsw now must
be built as modules when the bridge is a module - it just expressed
correctly that optional dependency. But the new behavior is an apparent
regression from Grygorii's perspective.

So to support the use case where the Ethernet driver is built-in,
NET_SWITCHDEV (a bool option) is enabled, and the bridge is a module, we
need a framework that can handle the possible absence of the bridge from
the running system, i.e. runtime bloatware as opposed to build-time
bloatware.

Luckily we already have this framework, since switchdev has been using
it extensively. Events from the bridge side are transmitted to the
driver side using notifier chains - this was originally done so that
unrelated drivers could snoop for events emitted by the bridge towards
ports that are implemented by other drivers (think of a switch driver
with LAG offload that listens for switchdev events on a bonding/team
interface that it offloads).

There are also events which are transmitted from the driver side to the
bridge side, which again are modeled using notifiers.
SWITCHDEV_FDB_ADD_TO_BRIDGE is an example of this, and deals with
notifying the bridge that a MAC address has been dynamically learned.
So there is a precedent we can use for modeling the new framework.

The difference compared to SWITCHDEV_FDB_ADD_TO_BRIDGE is that the work
that the bridge needs to do when a port becomes offloaded is blocking in
its nature: replay VLANs, MDBs etc. The calling context is indeed
blocking (we are under rtnl_mutex), but the existing switchdev
notification chain that the bridge is subscribed to is only the atomic
one. So we need to subscribe the bridge to the blocking switchdev
notification chain too.

This patch:
- keeps the driver-side perception of the switchdev_bridge_port_{,un}offload
unchanged
- moves the implementation of switchdev_bridge_port_{,un}offload from
the bridge module into the switchdev module.
- makes everybody that is subscribed to the switchdev blocking notifier
chain "hear" offload & unoffload events
- makes the bridge driver subscribe and handle those events
- moves the bridge driver's handling of those events into 2 new
functions called br_switchdev_port_{,un}offload. These functions
contain in fact the core of the logic that was previously in
switchdev_bridge_port_{,un}offload, just that now we go through an
extra indirection layer to reach them.

Unlike all the other switchdev notification structures, the structure
used to carry the bridge port information, struct
switchdev_notifier_brport_info, does not contain a "bool handled".
This is because in the current usage pattern, we always know that a
switchdev bridge port offloading event will be handled by the bridge,
because the switchdev_bridge_port_offload() call was initiated by a
NETDEV_CHANGEUPPER event in the first place, where info->upper_dev is a
bridge. So if the bridge wasn't loaded, then the CHANGEUPPER event
couldn't have happened.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: fix incorrect use of FDB flags when picking the dst device

Nikolay points out that it is incorrect to assume that it is impossible
to have an fdb entry with fdb->dst == NULL and the BR_FDB_LOCAL bit in
fdb->flags not set. This is because there are reader-side places that
test_bit(BR_FDB_LOCAL, &fdb->flags) without the br->hash_lock, and if
the updating of the FDB entry happens on another CPU, there are no
memory barriers at writer or reader side which would ensure that the
reader sees the updates to both fdb->flags and fdb->dst in the same
order, i.e. the reader will not see an inconsistent FDB entry.

So we must be prepared to deal with FDB entries where fdb->dst and
fdb->flags are in a potentially inconsistent state, and that means that
fdb->dst == NULL should remain a condition to pick the net_device that
we report to switchdev as being the bridge device, which is what the
code did prior to the blamed patch.

Fixes: 52e4bec15546 ("net: bridge: switchdev: treat local FDBs the same as entries towards the bridge")
Suggested-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Link: https://lore.kernel.org/r/20210802113633.189831-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: bridge: switchdev: treat local FDBs the same as entries towards the bridge

Currently the following script:

1. ip link add br0 type bridge vlan_filtering 1 && ip link set br0 up
2. ip link set swp2 up && ip link set swp2 master br0
3. ip link set swp3 up && ip link set swp3 master br0
4. ip link set swp4 up && ip link set swp4 master br0
5. bridge vlan del dev swp2 vid 1
6. bridge vlan del dev swp3 vid 1
7. ip link set swp4 nomaster
8. ip link set swp3 nomaster

produces the following output:

[ 641.010738] sja1105 spi0.1: port 2 failed to delete 00:1f:7b:63:02:48 vid 1 from fdb: -2

[ swp2, swp3 and br0 all have the same MAC address, the one listed above ]

In short, this happens because the number of FDB entry additions
notified to switchdev is unbalanced with the number of deletions.

At step 1, the bridge has a random MAC address. At step 2, the
br_fdb_replay of swp2 receives this initial MAC address. Then the bridge
inherits the MAC address of swp2 via br_fdb_change_mac_address(), and it
notifies switchdev (only swp2 at this point) of the deletion of the
random MAC address and the addition of 00:1f:7b:63:02:48 as a local FDB
entry with fdb->dst == swp2, in VLANs 0 and the default_pvid (1).

During step 7:

del_nbp
-> br_fdb_delete_by_port(br, p, vid=0, do_all=1);
-> fdb_delete_local(br, p, f);

br_fdb_delete_by_port() deletes all entries towards the ports,
regardless of vid, because do_all is 1.

fdb_delete_local() has logic to migrate local FDB entries deleted from
one port to another port which shares the same MAC address and is in the
same VLAN, or to the bridge device itself. This migration happens
without notifying switchdev of the deletion on the old port and the
addition on the new one, just fdb->dst is changed and the added_by_user
flag is cleared.

In the example above, the del_nbp(swp4) causes the
"addr 00:1f:7b:63:02:48 vid 1" local FDB entry with fdb->dst == swp4
that existed up until then to be migrated directly towards the bridge
(fdb->dst == NULL). This is because it cannot be migrated to any of the
other ports (swp2 and swp3 are not in VLAN 1).

After the migration to br0 takes place, swp4 requests a deletion replay
of all FDB entries. Since the "addr 00:1f:7b:63:02:48 vid 1" entry now
point towards the bridge, a deletion of it is replayed. There was just
a prior addition of this address, so the switchdev driver deletes this
entry.

Then, the del_nbp(swp3) at step 8 triggers another br_fdb_replay, and
switchdev is notified again to delete "addr 00:1f:7b:63:02:48 vid 1".
But it can't because it no longer has it, so it returns -ENOENT.

There are other possibilities to trigger this issue, but this is by far
the simplest to explain.

To fix this, we must avoid the situation where the addition of an FDB
entry is notified to switchdev as a local entry on a port, and the
deletion is notified on the bridge itself.

Considering that the 2 types of FDB entries are completely equivalent
and we cannot have the same MAC address as a local entry on 2 bridge
ports, or on a bridge port and pointing towards the bridge at the same
time, it makes sense to hide away from switchdev completely the fact
that a local FDB entry is associated with a given bridge port at all.
Just say that it points towards the bridge, it should make no difference
whatsoever to the switchdev driver and should even lead to a simpler
overall implementation, will less cases to handle.

This also avoids any modification at all to the core bridge driver, just
what is reported to switchdev changes. With the local/permanent entries
on bridge ports being already reported to user space, it is hard to
believe that the bridge behavior can change in any backwards-incompatible
way such as making all local FDB entries point towards the bridge.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: replay the entire FDB for each port

Currently when a switchdev port joins a bridge, we replay all FDB
entries pointing towards that port or towards the bridge.

However, this is insufficient in certain situations:

(a) DSA, through its assisted_learning_on_cpu_port logic, snoops
dynamically learned FDB entries on foreign interfaces.
These are FDB entries that are pointing neither towards the newly
joined switchdev port, nor towards the bridge. So these addresses
would be missed when joining a bridge where a foreign interface has
already learned some addresses, and they would also linger on if the
DSA port leaves the bridge before the foreign interface forgets them.
None of this happens if we replay the entire FDB when the port joins.

(b) There is a desire to treat local FDB entries on a port (i.e. the
port's termination MAC address) identically to FDB entries pointing
towards the bridge itself. More details on the reason behind this in
the next patch. The point is that this cannot be done given the
current structure of br_fdb_replay() in this situation:
ip link set swp0 master br0 # br0 inherits its MAC address from swp0
ip link set swp1 master br0
What is desirable is that when swp1 joins the bridge, br_fdb_replay()
also notifies swp1 of br0's MAC address, but this won't in fact
happen because the MAC address of br0 does not have fdb->dst == NULL
(it doesn't point towards the bridge), but it has fdb->dst == swp0.
So our current logic makes it impossible for that address to be
replayed. But if we dump the entire FDB instead of just the entries
with fdb->dst == swp1 and fdb->dst == NULL, then the inherited MAC
address of br0 will be replayed too, which is what we need.

A natural question arises: say there is an FDB entry to be replayed,
like a MAC address dynamically learned on a foreign interface that
belongs to a bridge where no switchdev port has joined yet. If 10
switchdev ports belonging to the same driver join this bridge, one by
one, won't every port get notified 10 times of the foreign FDB entry,
amounting to a total of 100 notifications for this FDB entry in the
switchdev driver?

Well, yes, but this is where the "void *ctx" argument for br_fdb_replay
is useful: every port of the switchdev driver is notified whenever any
other port requests an FDB replay, but because the replay was initiated
by a different port, its context is different from the initiating port's
context, so it ignores those replays.

So the foreign FDB entry will be installed only 10 times, once per port.
This is done so that the following 4 code paths are always well balanced:
(a) addition of foreign FDB entry is replayed when port joins bridge
(b) deletion of foreign FDB entry is replayed when port leaves bridge
(c) addition of foreign FDB entry is notified to all ports currently in bridge
(c) deletion of foreign FDB entry is notified to all ports currently in bridge

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: fix build when setting skb->offload_fwd_mark with CONFIG_NET_SWITCHDEV=n

Switchdev support can be disabled at compile time, and in that case,
struct sk_buff will not contain the offload_fwd_mark field.

To make the code in br_forward.c work in both cases, we do what is done
in other places and we create a helper function, with an empty shim
definition, that is implemented by the br_switchdev.o translation module.
This is always compiled if and only if CONFIG_NET_SWITCHDEV is y or m.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 472111920f1c ("net: bridge: switchdev: allow the TX data plane forwarding to be offloaded")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: allow the TX data plane forwarding to be offloaded

Allow switchdevs to forward frames from the CPU in accordance with the
bridge configuration in the same way as is done between bridge
ports. This means that the bridge will only send a single skb towards
one of the ports under the switchdev's control, and expects the driver
to deliver the packet to all eligible ports in its domain.

Primarily this improves the performance of multicast flows with
multiple subscribers, as it allows the hardware to perform the frame
replication.

The basic flow between the driver and the bridge is as follows:

- When joining a bridge port, the switchdev driver calls
switchdev_bridge_port_offload() with tx_fwd_offload = true.

- The bridge sends offloadable skbs to one of the ports under the
switchdev's control using skb->offload_fwd_mark = true.

- The switchdev driver checks the skb->offload_fwd_mark field and lets
its FDB lookup select the destination port mask for this packet.

v1->v2:
- convert br_input_skb_cb::fwd_hwdoms to a plain unsigned long
- introduce a static key "br_switchdev_fwd_offload_used" to minimize the
impact of the newly introduced feature on all the setups which don't
have hardware that can make use of it
- introduce a check for nbp->flags & BR_FWD_OFFLOAD to optimize cache
line access
- reorder nbp_switchdev_frame_mark_accel() and br_handle_vlan() in
__br_forward()
- do not strip VLAN on egress if forwarding offload on VLAN-aware bridge
is being used
- propagate errors from .ndo_dfwd_add_station() if not EOPNOTSUPP

v2->v3:
- replace the solution based on .ndo_dfwd_add_station with a solution
based on switchdev_bridge_port_offload
- rename BR_FWD_OFFLOAD to BR_TX_FWD_OFFLOAD
v3->v4: rebase
v4->v5:
- make sure the static key is decremented on bridge port unoffload
- more function and variable renaming and comments for them:
br_switchdev_fwd_offload_used to br_switchdev_tx_fwd_offload
br_switchdev_accels_skb to br_switchdev_frame_uses_tx_fwd_offload
nbp_switchdev_frame_mark_tx_fwd to nbp_switchdev_frame_mark_tx_fwd_to_hwdom
nbp_switchdev_frame_mark_accel to nbp_switchdev_frame_mark_tx_fwd_offload
fwd_accel to tx_fwd_offload

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
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>

net: bridge: move the switchdev object replay helpers to "push" mode

Starting with commit 4f2673b3a2b6 ("net: bridge: add helper to replay
port and host-joined mdb entries"), DSA has introduced some bridge
helpers that replay switchdev events (FDB/MDB/VLAN additions and
deletions) that can be lost by the switchdev drivers in a variety of
circumstances:

- an IP multicast group was host-joined on the bridge itself before any
switchdev port joined the bridge, leading to the host MDB entries
missing in the hardware database.
- during the bridge creation process, the MAC address of the bridge was
added to the FDB as an entry pointing towards the bridge device
itself, but with no switchdev ports being part of the bridge yet, this
local FDB entry would remain unknown to the switchdev hardware
database.
- a VLAN/FDB/MDB was added to a bridge port that is a LAG interface,
before any switchdev port joined that LAG, leading to the hardware
database missing those entries.
- a switchdev port left a LAG that is a bridge port, while the LAG
remained part of the bridge, and all FDB/MDB/VLAN entries remained
installed in the hardware database of the switchdev port.

Also, since commit 0d2cfbd41c4a ("net: bridge: ignore switchdev events
for LAG ports which didn't request replay"), DSA introduced a method,
based on a const void *ctx, to ensure that two switchdev ports under the
same LAG that is a bridge port do not see the same MDB/VLAN entry being
replayed twice by the bridge, once for every bridge port that joins the
LAG.

With so many ordering corner cases being possible, it seems unreasonable
to expect a switchdev driver writer to get it right from the first try.
Therefore, now that DSA has experimented with the bridge replay helpers
for a little bit, we can move the code to the bridge driver where it is
more readily available to all switchdev drivers.

To convert the switchdev object replay helpers from "pull mode" (where
the driver asks for them) to a "push mode" (where the bridge offers them
automatically), the biggest problem is that the bridge needs to be aware
when a switchdev port joins and leaves, even when the switchdev is only
indirectly a bridge port (for example when the bridge port is a LAG
upper of the switchdev).

Luckily, we already have a hook for that, in the form of the newly
introduced switchdev_bridge_port_offload() and
switchdev_bridge_port_unoffload() calls. These offer a natural place for
hooking the object addition and deletion replays.

Extend the above 2 functions with:
- pointers to the switchdev atomic notifier (for FDB replays) and the
blocking notifier (for MDB and VLAN replays).
- the "const void *ctx" argument required for drivers to be able to
disambiguate between which port is targeted, when multiple ports are
lowers of the same LAG that is a bridge port. Most of the drivers pass
NULL to this argument, except the ones that support LAG offload and have
the proper context check already in place in the switchdev blocking
notifier handler.

Also unexport the replay helpers, since nobody except the bridge calls
them directly now.

Note that:
(a) we abuse the terminology slightly, because FDB entries are not
"switchdev objects", but we count them as objects nonetheless.
With no direct way to prove it, I think they are not modeled as
switchdev objects because those can only be installed by the bridge
to the hardware (as opposed to FDB entries which can be propagated
in the other direction too). This is merely an abuse of terms, FDB
entries are replayed too, despite not being objects.
(b) the bridge does not attempt to sync port attributes to newly joined
ports, just the countable stuff (the objects). The reason for this
is simple: no universal and symmetric way to sync and unsync them is
known. For example, VLAN filtering: what to do on unsync, disable or
leave it enabled? Similarly, STP state, ageing timer, etc etc. What
a switchdev port does when it becomes standalone again is not really
up to the bridge's competence, and the driver should deal with it.
On the other hand, replaying deletions of switchdev objects can be
seen a matter of cleanup and therefore be treated by the bridge,
hence this patch.

We make the replay helpers opt-in for drivers, because they might not
bring immediate benefits for them:

- nbp_vlan_init() is called _after_ netdev_master_upper_dev_link(),
so br_vlan_replay() should not do anything for the new drivers on
which we call it. The existing drivers where there was even a slight
possibility for there to exist a VLAN on a bridge port before they
join it are already guarded against this: mlxsw and prestera deny
joining LAG interfaces that are members of a bridge.

- br_fdb_replay() should now notify of local FDB entries, but I patched
all drivers except DSA to ignore these new entries in commit
2c4eca3ef716 ("net: bridge: switchdev: include local flag in FDB
notifications"). Driver authors can lift this restriction as they
wish, and when they do, they can also opt into the FDB replay
functionality.

- br_mdb_replay() should fix a real issue which is described in commit
4f2673b3a2b6 ("net: bridge: add helper to replay port and host-joined
mdb entries"). However most drivers do not offload the
SWITCHDEV_OBJ_ID_HOST_MDB to see this issue: only cpsw and am65_cpsw
offload this switchdev object, and I don't completely understand the
way in which they offload this switchdev object anyway. So I'll leave
it up to these drivers' respective maintainers to opt into
br_mdb_replay().

So most of the drivers pass NULL notifier blocks for the replay helpers,
except:
- dpaa2-switch which was already acked/regression-tested with the
helpers enabled (and there isn't much of a downside in having them)
- ocelot which already had replay logic in "pull" mode
- DSA which already had replay logic in "pull" mode

An important observation is that the drivers which don't currently
request bridge event replays don't even have the
switchdev_bridge_port_{offload,unoffload} calls placed in proper places
right now. This was done to avoid unnecessary rework for drivers which
might never even add support for this. For driver writers who wish to
add replay support, this can be used as a tentative placement guide:
https://patchwork.kernel.org/project/netdevbpf/patch/20210720134655.892334-11-vladimir.oltean@nxp.com/

Cc: Vadym Kochan <vkochan@marvell.com>
Cc: Taras Chornyi <tchornyi@marvell.com>
Cc: Ioana Ciornei <ioana.ciornei@nxp.com>
Cc: Lars Povlsen <lars.povlsen@microchip.com>
Cc: Steen Hegelund <Steen.Hegelund@microchip.com>
Cc: UNGLinuxDriver@microchip.com
Cc: Claudiu Manoil <claudiu.manoil@nxp.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Ioana Ciornei <ioana.ciornei@nxp.com> # dpaa2-switch
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: let drivers inform which bridge ports are offloaded

On reception of an skb, the bridge checks if it was marked as 'already
forwarded in hardware' (checks if skb->offload_fwd_mark == 1), and if it
is, it assigns the source hardware domain of that skb based on the
hardware domain of the ingress port. Then during forwarding, it enforces
that the egress port must have a different hardware domain than the
ingress one (this is done in nbp_switchdev_allowed_egress).

Non-switchdev drivers don't report any physical switch id (neither
through devlink nor .ndo_get_port_parent_id), therefore the bridge
assigns them a hardware domain of 0, and packets coming from them will
always have skb->offload_fwd_mark = 0. So there aren't any restrictions.

Problems appear due to the fact that DSA would like to perform software
fallback for bonding and team interfaces that the physical switch cannot
offload.

+-- br0 ---+
/ / | \
/ / | \
/ | | bond0
/ | | / \
swp0 swp1 swp2 swp3 swp4

There, it is desirable that the presence of swp3 and swp4 under a
non-offloaded LAG does not preclude us from doing hardware bridging
beteen swp0, swp1 and swp2. The bandwidth of the CPU is often times high
enough that software bridging between {swp0,swp1,swp2} and bond0 is not
impractical.

But this creates an impossible paradox given the current way in which
port hardware domains are assigned. When the driver receives a packet
from swp0 (say, due to flooding), it must set skb->offload_fwd_mark to
something.

- If we set it to 0, then the bridge will forward it towards swp1, swp2
and bond0. But the switch has already forwarded it towards swp1 and
swp2 (not to bond0, remember, that isn't offloaded, so as far as the
switch is concerned, ports swp3 and swp4 are not looking up the FDB,
and the entire bond0 is a destination that is strictly behind the
CPU). But we don't want duplicated traffic towards swp1 and swp2, so
it's not ok to set skb->offload_fwd_mark = 0.

- If we set it to 1, then the bridge will not forward the skb towards
the ports with the same switchdev mark, i.e. not to swp1, swp2 and
bond0. Towards swp1 and swp2 that's ok, but towards bond0? It should
have forwarded the skb there.

So the real issue is that bond0 will be assigned the same hardware
domain as {swp0,swp1,swp2}, because the function that assigns hardware
domains to bridge ports, nbp_switchdev_add(), recurses through bond0's
lower interfaces until it finds something that implements devlink (calls
dev_get_port_parent_id with bool recurse = true). This is a problem
because the fact that bond0 can be offloaded by swp3 and swp4 in our
example is merely an assumption.

A solution is to give the bridge explicit hints as to what hardware
domain it should use for each port.

Currently, the bridging offload is very 'silent': a driver registers a
netdevice notifier, which is put on the netns's notifier chain, and
which sniffs around for NETDEV_CHANGEUPPER events where the upper is a
bridge, and the lower is an interface it knows about (one registered by
this driver, normally). Then, from within that notifier, it does a bunch
of stuff behind the bridge's back, without the bridge necessarily
knowing that there's somebody offloading that port. It looks like this:

ip link set swp0 master br0
|
v
br_add_if() calls netdev_master_upper_dev_link()
|
v
call_netdevice_notifiers
|
v
dsa_slave_netdevice_event
|
v
oh, hey! it's for me!
|
v
.port_bridge_join

What we do to solve the conundrum is to be less silent, and change the
switchdev drivers to present themselves to the bridge. Something like this:

ip link set swp0 master br0
|
v
br_add_if() calls netdev_master_upper_dev_link()
|
v bridge: Aye! I'll use this
call_netdevice_notifiers ^ ppid as the
| | hardware domain for
v | this port, and zero
dsa_slave_netdevice_event | if I got nothing.
| |
v |
oh, hey! it's for me! |
| |
v |
.port_bridge_join |
| |
+------------------------+
switchdev_bridge_port_offload(swp0, swp0)

Then stacked interfaces (like bond0 on top of swp3/swp4) would be
treated differently in DSA, depending on whether we can or cannot
offload them.

The offload case:

ip link set bond0 master br0
|
v
br_add_if() calls netdev_master_upper_dev_link()
|
v bridge: Aye! I'll use this
call_netdevice_notifiers ^ ppid as the
| | switchdev mark for
v | bond0.
dsa_slave_netdevice_event | Coincidentally (or not),
| | bond0 and swp0, swp1, swp2
v | all have the same switchdev
hmm, it's not quite for me, | mark now, since the ASIC
but my driver has already | is able to forward towards
called .port_lag_join | all these ports in hw.
for it, because I have |
a port with dp->lag_dev == bond0. |
| |
v |
.port_bridge_join |
for swp3 and swp4 |
| |
+------------------------+
switchdev_bridge_port_offload(bond0, swp3)
switchdev_bridge_port_offload(bond0, swp4)

And the non-offload case:

ip link set bond0 master br0
|
v
br_add_if() calls netdev_master_upper_dev_link()
|
v bridge waiting:
call_netdevice_notifiers ^ huh, switchdev_bridge_port_offload
| | wasn't called, okay, I'll use a
v | hwdom of zero for this one.
dsa_slave_netdevice_event : Then packets received on swp0 will
| : not be software-forwarded towards
v : swp1, but they will towards bond0.
it's not for me, but
bond0 is an upper of swp3
and swp4, but their dp->lag_dev
is NULL because they couldn't
offload it.

Basically we can draw the conclusion that the lowers of a bridge port
can come and go, so depending on the configuration of lowers for a
bridge port, it can dynamically toggle between offloaded and unoffloaded.
Therefore, we need an equivalent switchdev_bridge_port_unoffload too.

This patch changes the way any switchdev driver interacts with the
bridge. From now on, everybody needs to call switchdev_bridge_port_offload
and switchdev_bridge_port_unoffload, otherwise the bridge will treat the
port as non-offloaded and allow software flooding to other ports from
the same ASIC.

Note that these functions lay the ground for a more complex handshake
between switchdev drivers and the bridge in the future.

For drivers that will request a replay of the switchdev objects when
they offload and unoffload a bridge port (DSA, dpaa2-switch, ocelot), we
place the call to switchdev_bridge_port_unoffload() strategically inside
the NETDEV_PRECHANGEUPPER notifier's code path, and not inside
NETDEV_CHANGEUPPER. This is because the switchdev object replay helpers
need the netdev adjacency lists to be valid, and that is only true in
NETDEV_PRECHANGEUPPER.

Cc: Vadym Kochan <vkochan@marvell.com>
Cc: Taras Chornyi <tchornyi@marvell.com>
Cc: Ioana Ciornei <ioana.ciornei@nxp.com>
Cc: Lars Povlsen <lars.povlsen@microchip.com>
Cc: Steen Hegelund <Steen.Hegelund@microchip.com>
Cc: UNGLinuxDriver@microchip.com
Cc: Claudiu Manoil <claudiu.manoil@nxp.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Ioana Ciornei <ioana.ciornei@nxp.com> # dpaa2-switch: regression
Acked-by: Ioana Ciornei <ioana.ciornei@nxp.com> # dpaa2-switch
Tested-by: Horatiu Vultur <horatiu.vultur@microchip.com> # ocelot-switch
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: recycle unused hwdoms

Since hwdoms have only been used thus far for equality comparisons, the
bridge has used the simplest possible assignment policy; using a
counter to keep track of the last value handed out.

With the upcoming transmit offloading, we need to perform set
operations efficiently based on hwdoms, e.g. we want to answer
questions like "has this skb been forwarded to any port within this
hwdom?"

Move to a bitmap-based allocation scheme that recycles hwdoms once all
members leaves the bridge. This means that we can use a single
unsigned long to keep track of the hwdoms that have received an skb.

v1->v2: convert the typedef DECLARE_BITMAP(br_hwdom_map_t, BR_HWDOM_MAX)
into a plain unsigned long.
v2->v6: none

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: disambiguate offload_fwd_mark

Before this change, four related - but distinct - concepts where named
offload_fwd_mark:

- skb->offload_fwd_mark: Set by the switchdev driver if the underlying
hardware has already forwarded this frame to the other ports in the
same hardware domain.

- nbp->offload_fwd_mark: An idetifier used to group ports that share
the same hardware forwarding domain.

- br->offload_fwd_mark: Counter used to make sure that unique IDs are
used in cases where a bridge contains ports from multiple hardware
domains.

- skb->cb->offload_fwd_mark: The hardware domain on which the frame
ingressed and was forwarded.

Introduce the term "hardware forwarding domain" ("hwdom") in the
bridge to denote a set of ports with the following property:

If an skb with skb->offload_fwd_mark set, is received on a port
belonging to hwdom N, that frame has already been forwarded to all
other ports in hwdom N.

By decoupling the name from "offload_fwd_mark", we can extend the
term's definition in the future - e.g. to add constraints that
describe expected egress behavior - without overloading the meaning of
"offload_fwd_mark".

- nbp->offload_fwd_mark thus becomes nbp->hwdom.

- br->offload_fwd_mark becomes br->last_hwdom.

- skb->cb->offload_fwd_mark becomes skb->cb->src_hwdom. The slight
change in naming here mandates a slight change in behavior of the
nbp_switchdev_frame_mark() function. Previously, it only set this
value in skb->cb for packets with skb->offload_fwd_mark true (ones
which were forwarded in hardware). Whereas now we always track the
incoming hwdom for all packets coming from a switchdev (even for the
packets which weren't forwarded in hardware, such as STP BPDUs, IGMP
reports etc). As all uses of skb->cb->offload_fwd_mark were already
gated behind checks of skb->offload_fwd_mark, this will not introduce
any functional change, but it paves the way for future changes where
the ingressing hwdom must be known for frames coming from a switchdev
regardless of whether they were forwarded in hardware or not
(basically, if the skb comes from a switchdev, skb->cb->src_hwdom now
always tracks which one).

A typical example where this is relevant: the switchdev has a fixed
configuration to trap STP BPDUs, but STP is not running on the bridge
and the group_fwd_mask allows them to be forwarded. Say we have this
setup:

br0
/ | \
/ | \
swp0 swp1 swp2

A BPDU comes in on swp0 and is trapped to the CPU; the driver does not
set skb->offload_fwd_mark. The bridge determines that the frame should
be forwarded to swp{1,2}. It is imperative that forward offloading is
_not_ allowed in this case, as the source hwdom is already "poisoned".

Recording the source hwdom allows this case to be handled properly.

v2->v3: added code comments
v3->v6: none

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: send FDB notifications for host addresses

Treat addresses added to the bridge itself in the same way as regular
ports and send out a notification so that drivers may sync it down to
the hardware FDB.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: use READ_ONCE() and WRITE_ONCE() compiler barriers for fdb->dst

Annotate the writer side of fdb->dst:

- fdb_create()
- br_fdb_update()
- fdb_add_entry()
- br_fdb_external_learn_add()

with WRITE_ONCE() and the reader side:

- br_fdb_test_addr()
- br_fdb_update()
- fdb_fill_info()
- fdb_add_entry()
- fdb_delete_by_addr_and_port()
- br_fdb_external_learn_add()
- br_switchdev_fdb_notify()

with compiler barriers such that the readers do not attempt to reload
fdb->dst multiple times, leading to potentially different destination
ports when the fdb entry is updated concurrently.

This is especially important in read-side sections where fdb->dst is
used more than once, but let's convert all accesses for the sake of
uniformity.

Suggested-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: include local flag in FDB notifications

As explained in bugfix commit 6ab4c3117aec ("net: bridge: don't notify
switchdev for local FDB addresses") as well as in this discussion:
https://lore.kernel.org/netdev/20210117193009.io3nungdwuzmo5f7@skbuf/

the switchdev notifiers for FDB entries managed to have a zero-day bug,
which was that drivers would not know what to do with local FDB entries,
because they were not told that they are local. The bug fix was to
simply not notify them of those addresses.

Let us now add the 'is_local' bit to bridge FDB entries, and make all
drivers ignore these entries by their own choice.

Co-developed-by: Tobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: switchdev: refactor br_switchdev_fdb_notify

Instead of having to add more and more arguments to
br_switchdev_fdb_call_notifiers, get rid of it and build the info
struct directly in br_switchdev_fdb_notify.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: don't notify switchdev for local FDB addresses

As explained in this discussion:
https://lore.kernel.org/netdev/20210117193009.io3nungdwuzmo5f7@skbuf/

the switchdev notifiers for FDB entries managed to have a zero-day bug.
The bridge would not say that this entry is local:

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

and the switchdev driver would be more than happy to offload it as a
normal static FDB entry. This is despite the fact that 'local' and
non-'local' entries have completely opposite directions: a local entry
is locally terminated and not forwarded, whereas a static entry is
forwarded and not locally terminated. So, for example, DSA would install
this entry on swp0 instead of installing it on the CPU port as it should.

There is an even sadder part, which is that the 'local' flag is implicit
if 'static' is not specified, meaning that this command produces the
same result of adding a 'local' entry:

bridge fdb add dev swp0 00:01:02:03:04:05 master

I've updated the man pages for 'bridge', and after reading it now, it
should be pretty clear to any user that the commands above were broken
and should have never resulted in the 00:01:02:03:04:05 address being
forwarded (this behavior is coherent with non-switchdev interfaces):
https://patchwork.kernel.org/project/netdevbpf/cover/20210211104502.2081443-1-olteanv@gmail.com/
If you're a user reading this and this is what you want, just use:

bridge fdb add dev swp0 00:01:02:03:04:05 master static

Because switchdev should have given drivers the means from day one to
classify FDB entries as local/non-local, but didn't, it means that all
drivers are currently broken. So we can just as well omit the switchdev
notifications for local FDB entries, which is exactly what this patch
does to close the bug in stable trees. For further development work
where drivers might want to trap the local FDB entries to the host, we
can add a 'bool is_local' to br_switchdev_fdb_call_notifiers(), and
selectively make drivers act upon that bit, while all the others ignore
those entries if the 'is_local' bit is set.

Fixes: 6b26b51b1d13 ("net: bridge: Add support for notifying devices about FDB add/del")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: propagate extack through switchdev_port_attr_set

The benefit is the ability to propagate errors from switchdev drivers
for the SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING and
SWITCHDEV_ATTR_ID_BRIDGE_VLAN_PROTOCOL attributes.

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>

net: switchdev: pass flags and mask to both {PRE_,}BRIDGE_FLAGS attributes

This switchdev attribute offers a counterproductive API for a driver
writer, because although br_switchdev_set_port_flag gets passed a
"flags" and a "mask", those are passed piecemeal to the driver, so while
the PRE_BRIDGE_FLAGS listener knows what changed because it has the
"mask", the BRIDGE_FLAGS listener doesn't, because it only has the final
value. But certain drivers can offload only certain combinations of
settings, like for example they cannot change unicast flooding
independently of multicast flooding - they must be both on or both off.
The way the information is passed to switchdev makes drivers not
expressive enough, and unable to reject this request ahead of time, in
the PRE_BRIDGE_FLAGS notifier, so they are forced to reject it during
the deferred BRIDGE_FLAGS attribute, where the rejection is currently
ignored.

This patch also changes drivers to make use of the "mask" field for edge
detection when possible.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: don't print in br_switchdev_set_port_flag

For the netlink interface, propagate errors through extack rather than
simply printing them to the console. For the sysfs interface, we still
print to the console, but at least that's one layer higher than in
switchdev, which also allows us to silently ignore the offloading of
flags if that is ever needed in the future.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: offload all port flags at once in br_setport

If for example this command:

ip link set swp0 type bridge_slave flood off mcast_flood off learning off

succeeded at configuring BR_FLOOD and BR_MCAST_FLOOD but not at
BR_LEARNING, there would be no attempt to revert the partial state in
any way. Arguably, if the user changes more than one flag through the
same netlink command, this one _should_ be all or nothing, which means
it should be passed through switchdev as all or nothing.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: switchdev: remove vid_begin -> vid_end range from VLAN objects

The call path of a switchdev VLAN addition to the bridge looks something
like this today:

nbp_vlan_init
| __br_vlan_set_default_pvid
| | |
| | br_afspec |
| | | |
| | v |
| | br_process_vlan_info |
| | | |
| | v |
| | br_vlan_info |
| | / \ /
| | / \ /
| | / \ /
| | / \ /
v v v v v
nbp_vlan_add br_vlan_add ------+
| ^ ^ | |
| / | | |
| / / / |
\ br_vlan_get_master/ / v
\ ^ / / br_vlan_add_existing
\ | / / |
\ | / / /
\ | / / /
\ | / / /
\ | / / /
v | | v /
__vlan_add /
/ | /
/ | /
v | /
__vlan_vid_add | /
\ | /
v v v
br_switchdev_port_vlan_add

The ranges UAPI was introduced to the bridge in commit bdced7ef7838
("bridge: support for multiple vlans and vlan ranges in setlink and
dellink requests") (Jan 10 2015). But the VLAN ranges (parsed in br_afspec)
have always been passed one by one, through struct bridge_vlan_info
tmp_vinfo, to br_vlan_info. So the range never went too far in depth.

Then Scott Feldman introduced the switchdev_port_bridge_setlink function
in commit 47f8328bb1a4 ("switchdev: add new switchdev bridge setlink").
That marked the introduction of the SWITCHDEV_OBJ_PORT_VLAN, which made
full use of the range. But switchdev_port_bridge_setlink was called like
this:

br_setlink
-> br_afspec
-> switchdev_port_bridge_setlink

Basically, the switchdev and the bridge code were not tightly integrated.
Then commit 41c498b9359e ("bridge: restore br_setlink back to original")
came, and switchdev drivers were required to implement
.ndo_bridge_setlink = switchdev_port_bridge_setlink for a while.

In the meantime, commits such as 0944d6b5a2fa ("bridge: try switchdev op
first in __vlan_vid_add/del") finally made switchdev penetrate the
br_vlan_info() barrier and start to develop the call path we have today.
But remember, br_vlan_info() still receives VLANs one by one.

Then Arkadi Sharshevsky refactored the switchdev API in 2017 in commit
29ab586c3d83 ("net: switchdev: Remove bridge bypass support from
switchdev") so that drivers would not implement .ndo_bridge_setlink any
longer. The switchdev_port_bridge_setlink also got deleted.
This refactoring removed the parallel bridge_setlink implementation from
switchdev, and left the only switchdev VLAN objects to be the ones
offloaded from __vlan_vid_add (basically RX filtering) and __vlan_add
(the latter coming from commit 9c86ce2c1ae3 ("net: bridge: Notify about
bridge VLANs")).

That is to say, today the switchdev VLAN object ranges are not used in
the kernel. Refactoring the above call path is a bit complicated, when
the bridge VLAN call path is already a bit complicated.

Let's go off and finish the job of commit 29ab586c3d83 by deleting the
bogus iteration through the VLAN ranges from the drivers. Some aspects
of this feature never made too much sense in the first place. For
example, what is a range of VLANs all having the BRIDGE_VLAN_INFO_PVID
flag supposed to mean, when a port can obviously have a single pvid?
This particular configuration _is_ denied as of commit 6623c60dc28e
("bridge: vlan: enforce no pvid flag in vlan ranges"), but from an API
perspective, the driver still has to play pretend, and only offload the
vlan->vid_end as pvid. And the addition of a switchdev VLAN object can
modify the flags of another, completely unrelated, switchdev VLAN
object! (a VLAN that is PVID will invalidate the PVID flag from whatever
other VLAN had previously been offloaded with switchdev and had that
flag. Yet switchdev never notifies about that change, drivers are
supposed to guess).

Nonetheless, having a VLAN range in the API makes error handling look
scarier than it really is - unwinding on errors and all of that.
When in reality, no one really calls this API with more than one VLAN.
It is all unnecessary complexity.

And despite appearing pretentious (two-phase transactional model and
all), the switchdev API is really sloppy because the VLAN addition and
removal operations are not paired with one another (you can add a VLAN
100 times and delete it just once). The bridge notifies through
switchdev of a VLAN addition not only when the flags of an existing VLAN
change, but also when nothing changes. There are switchdev drivers out
there who don't like adding a VLAN that has already been added, and
those checks don't really belong at driver level. But the fact that the
API contains ranges is yet another factor that prevents this from being
addressed in the future.

Of the existing switchdev pieces of hardware, it appears that only
Mellanox Spectrum supports offloading more than one VLAN at a time,
through mlxsw_sp_port_vlan_set. I have kept that code internal to the
driver, because there is some more bookkeeping that makes use of it, but
I deleted it from the switchdev API. But since the switchdev support for
ranges has already been de facto deleted by a Mellanox employee and
nobody noticed for 4 years, I'm going to assume it's not a biggie.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com> # switchdev and mlxsw
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de> # hellcreek
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: bridge: fdb: convert offloaded to use bitops

Convert the offloaded field to a flag and use bitops.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: fdb: convert added_by_user to bitops

Straight-forward convert of the added_by_user field to bitops.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: switchdev: Replace port attr set SDO with a notification

Drop switchdev_ops.switchdev_port_attr_set. Drop the uses of this field
from all clients, which were migrated to use switchdev notification in
the previous patches.

Add a new function switchdev_port_attr_notify() that sends the switchdev
notifications SWITCHDEV_PORT_ATTR_SET and calls the blocking (process)
notifier chain.

We have one odd case within net/bridge/br_switchdev.c with the
SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS attribute identifier that
requires executing from atomic context, we deal with that one
specifically.

Drop __switchdev_port_attr_set() and update switchdev_port_attr_set()
likewise.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: Stop calling switchdev_port_attr_get()

Now that all switchdev drivers have been converted to check the
SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS flags and report flags that they
do not support accordingly, we can migrate the bridge code to try to set
that attribute first, check the results and then do the actual setting.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Get rid of SWITCHDEV_ATTR_ID_PORT_PARENT_ID

Now that we have a dedicated NDO for getting a port's parent ID, get rid
of SWITCHDEV_ATTR_ID_PORT_PARENT_ID and convert all callers to use the
NDO exclusively. This is a preliminary change to getting rid of
switchdev_ops eventually.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Introduce ndo_get_port_parent_id()

In preparation for getting rid of switchdev_ops, create a dedicated NDO
operation for getting the port's parent identifier. There are
essentially two classes of drivers that need to implement getting the
port's parent ID which are VF/PF drivers with a built-in switch, and
pure switchdev drivers such as mlxsw, ocelot, dsa etc.

We introduce a helper function: dev_get_port_parent_id() which supports
recursion into the lower devices to obtain the first port's parent ID.

Convert the bridge, core and ipv4 multicast routing code to check for
such ndo_get_port_parent_id() and call the helper function when valid
before falling back to switchdev_port_attr_get(). This will allow us to
convert all relevant drivers in one go instead of having to implement
both switchdev_port_attr_get() and ndo_get_port_parent_id() operations,
then get rid of switchdev_port_attr_get().

Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

switchdev: Add extack argument to call_switchdev_notifiers()

A follow-up patch will enable vetoing of FDB entries. Make it possible
to communicate details of why an FDB entry is not acceptable back to the
user.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: switchdev: Add extack argument to switchdev_port_obj_add()

After the previous patch, bridge driver has extack argument available to
pass to switchdev. Therefore extend switchdev_port_obj_add() with this
argument, updating all callers, and passing the argument through to
switchdev_port_obj_notify().

Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Ivan Vecera <ivecera@redhat.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: Propagate extack to switchdev

ndo_bridge_setlink has been updated in the previous patch to have extack
available, and changelink RTNL op has had this argument since the time
extack was added. Propagate both through the bridge driver to eventually
reach br_switchdev_port_vlan_add(), where it will be used by subsequent
patches.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: Ivan Vecera <ivecera@redhat.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

bridge: switchdev: Allow clearing FDB entry offload indication

Currently, an FDB entry only ceases being offloaded when it is deleted.
This changes with VxLAN encapsulation.

Devices capable of performing VxLAN encapsulation usually have only one
FDB table, unlike the software data path which has two - one in the
bridge driver and another in the VxLAN driver.

Therefore, bridge FDB entries pointing to a VxLAN device are only
offloaded if there is a corresponding entry in the VxLAN FDB.

Allow clearing the offload indication in case the corresponding entry
was deleted from the VxLAN FDB.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: Extract boilerplate around switchdev_port_obj_*()

A call to switchdev_port_obj_add() or switchdev_port_obj_del() involves
initializing a struct switchdev_obj_port_vlan, a piece of code that
repeats on each call site almost verbatim. While in the current codebase
there is just one duplicated add call, the follow-up patches add more of
both add and del calls.

Thus to remove the duplication, extract the repetition into named
functions and reuse.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: Notify about !added_by_user FDB entries

Do not automatically bail out on sending notifications about activity on
non-user-added FDB entries. Instead, notify about this activity except
for cases where the activity itself originates in a notification, to
avoid sending duplicate notifications.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

switchdev: Add fdb.added_by_user to switchdev notifications

The following patch enables sending notifications also for events on FDB
entries that weren't added by the user. Give the drivers the information
necessary to distinguish between the two origins of FDB entries.

To maintain the current behavior, have switchdev-implementing drivers
bail out on notifications about non-user-added FDB entries. In case of
mlxsw driver, allow a call to mlxsw_sp_span_respin() so that SPAN over
bridge catches up with the changed FDB.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: use rhashtable for fdbs

Before this patch the bridge used a fixed 256 element hash table which
was fine for small use cases (in my tests it starts to degrade
above 1000 entries), but it wasn't enough for medium or large
scale deployments. Modern setups have thousands of participants in a
single bridge, even only enabling vlans and adding a few thousand vlan
entries will cause a few thousand fdbs to be automatically inserted per
participating port. So we need to scale the fdb table considerably to
cope with modern workloads, and this patch converts it to use a
rhashtable for its operations thus improving the bridge scalability.
Tests show the following results (10 runs each), at up to 1000 entries
rhashtable is ~3% slower, at 2000 rhashtable is 30% faster, at 3000 it
is 2 times faster and at 30000 it is 50 times faster.
Obviously this happens because of the properties of the two constructs
and is expected, rhashtable keeps pretty much a constant time even with
10000000 entries (tested), while the fixed hash table struggles
considerably even above 10000.
As a side effect this also reduces the net_bridge struct size from 3248
bytes to 1344 bytes. Also note that the key struct is 8 bytes.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

bridge: check for null fdb->dst before notifying switchdev drivers

current switchdev drivers dont seem to support offloading fdb
entries pointing to the bridge device which have fdb->dst
not set to any port. This patch adds a NULL fdb->dst check in
the switchdev notifier code.

This patch fixes the below NULL ptr dereference:
$bridge fdb add 00:02:00:00:00:33 dev br0 self

[ 69.953374] BUG: unable to handle kernel NULL pointer dereference at
0000000000000008
[ 69.954044] IP: br_switchdev_fdb_notify+0x29/0x80
[ 69.954044] PGD 66527067
[ 69.954044] P4D 66527067
[ 69.954044] PUD 7899c067
[ 69.954044] PMD 0
[ 69.954044]
[ 69.954044] Oops: 0000 [#1] SMP
[ 69.954044] Modules linked in:
[ 69.954044] CPU: 1 PID: 3074 Comm: bridge Not tainted 4.13.0-rc6+ #1
[ 69.954044] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.7.5.1-0-g8936dbb-20141113_115728-nilsson.home.kraxel.org
04/01/2014
[ 69.954044] task: ffff88007b827140 task.stack: ffffc90001564000
[ 69.954044] RIP: 0010:br_switchdev_fdb_notify+0x29/0x80
[ 69.954044] RSP: 0018:ffffc90001567918 EFLAGS: 00010246
[ 69.954044] RAX: 0000000000000000 RBX: ffff8800795e0880 RCX:
00000000000000c0
[ 69.954044] RDX: ffffc90001567920 RSI: 000000000000001c RDI:
ffff8800795d0600
[ 69.954044] RBP: ffffc90001567938 R08: ffff8800795d0600 R09:
0000000000000000
[ 69.954044] R10: ffffc90001567a88 R11: ffff88007b849400 R12:
ffff8800795e0880
[ 69.954044] R13: ffff8800795d0600 R14: ffffffff81ef8880 R15:
000000000000001c
[ 69.954044] FS: 00007f93d3085700(0000) GS:ffff88007fd00000(0000)
knlGS:0000000000000000
[ 69.954044] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 69.954044] CR2: 0000000000000008 CR3: 0000000066551000 CR4:
00000000000006e0
[ 69.954044] Call Trace:
[ 69.954044] fdb_notify+0x3f/0xf0
[ 69.954044] __br_fdb_add.isra.12+0x1a7/0x370
[ 69.954044] br_fdb_add+0x178/0x280
[ 69.954044] rtnl_fdb_add+0x10a/0x200
[ 69.954044] rtnetlink_rcv_msg+0x1b4/0x240
[ 69.954044] ? skb_free_head+0x21/0x40
[ 69.954044] ? rtnl_calcit.isra.18+0xf0/0xf0
[ 69.954044] netlink_rcv_skb+0xed/0x120
[ 69.954044] rtnetlink_rcv+0x15/0x20
[ 69.954044] netlink_unicast+0x180/0x200
[ 69.954044] netlink_sendmsg+0x291/0x370
[ 69.954044] ___sys_sendmsg+0x180/0x2e0
[ 69.954044] ? filemap_map_pages+0x2db/0x370
[ 69.954044] ? do_wp_page+0x11d/0x420
[ 69.954044] ? __handle_mm_fault+0x794/0xd80
[ 69.954044] ? vma_link+0xcb/0xd0
[ 69.954044] __sys_sendmsg+0x4c/0x90
[ 69.954044] SyS_sendmsg+0x12/0x20
[ 69.954044] do_syscall_64+0x63/0xe0
[ 69.954044] entry_SYSCALL64_slow_path+0x25/0x25
[ 69.954044] RIP: 0033:0x7f93d2bad690
[ 69.954044] RSP: 002b:00007ffc7217a638 EFLAGS: 00000246 ORIG_RAX:
000000000000002e
[ 69.954044] RAX: ffffffffffffffda RBX: 00007ffc72182eac RCX:
00007f93d2bad690
[ 69.954044] RDX: 0000000000000000 RSI: 00007ffc7217a670 RDI:
0000000000000003
[ 69.954044] RBP: 0000000059a1f7f8 R08: 0000000000000006 R09:
000000000000000a
[ 69.954044] R10: 00007ffc7217a400 R11: 0000000000000246 R12:
00007ffc7217a670
[ 69.954044] R13: 00007ffc72182a98 R14: 00000000006114c0 R15:
00007ffc72182aa0
[ 69.954044] Code: 1f 00 66 66 66 66 90 55 48 89 e5 48 83 ec 20 f6 47
20 04 74 0a 83 fe 1c 74 09 83 fe 1d 74 2c c9 66 90 c3 48 8b 47 10 48 8d
55 e8 <48> 8b 70 08 0f b7 47 1e 48 83 c7 18 48 89 7d f0 bf 03 00 00 00
[ 69.954044] RIP: br_switchdev_fdb_notify+0x29/0x80 RSP:
ffffc90001567918
[ 69.954044] CR2: 0000000000000008
[ 69.954044] ---[ end trace 03e9eec4a82c238b ]---

Fixes: 6b26b51b1d13 ("net: bridge: Add support for notifying devices about FDB add/del")
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: Add support for notifying devices about FDB add/del

Currently the bridge doesn't notify the underlying devices about new
FDBs learned. The FDB sync is placed on the switchdev notifier chain
because devices may potentially learn FDB that are not directly related
to their ports, for example:

1. Mixed SW/HW bridge - FDBs that point to the ASICs external devices
should be offloaded as CPU traps in order to
perform forwarding in slow path.
2. EVPN - Externally learned FDBs for the vtep device.

Notification is sent only about static FDB add/del. This is done due
to fact that currently this is the only scenario supported by switch
drivers.

Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Reviewed-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: bridge: Add support for offloading port attributes

Currently the flood, learning and learning_sync port attributes are
offloaded by setting the SELF flag. Add support for offloading the
flood and learning attribute through the bridge code. In case of
setting an unsupported flag on a offloded port the operation will
fail.

The learning_sync attribute doesn't have any software representation
and cannot be offloaded through the bridge code.

Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Reviewed-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

bridge: switchdev: Add forward mark support for stacked devices

switchdev_port_fwd_mark_set() is used to set the 'offload_fwd_mark' of
port netdevs so that packets being flooded by the device won't be
flooded twice.

It works by assigning a unique identifier (the ifindex of the first
bridge port) to bridge ports sharing the same parent ID. This prevents
packets from being flooded twice by the same switch, but will flood
packets through bridge ports belonging to a different switch.

This method is problematic when stacked devices are taken into account,
such as VLANs. In such cases, a physical port netdev can have upper
devices being members in two different bridges, thus requiring two
different 'offload_fwd_mark's to be configured on the port netdev, which
is impossible.

The main problem is that packet and netdev marking is performed at the
physical netdev level, whereas flooding occurs between bridge ports,
which are not necessarily port netdevs.

Instead, packet and netdev marking should really be done in the bridge
driver with the switch driver only telling it which packets it already
forwarded. The bridge driver will mark such packets using the mark
assigned to the ingress bridge port and will prevent the packet from
being forwarded through any bridge port sharing the same mark (i.e.
having the same parent ID).

Remove the current switchdev 'offload_fwd_mark' implementation and
instead implement the proposed method. In addition, make rocker - the
sole user of the mark - use the proposed method.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>