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From: Vladimir Oltean <olteanv@gmail.com>
To: Jakub Kicinski <kuba@kernel.org>,
	"David S. Miller" <davem@davemloft.net>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Tobias Waldekranz <tobias@waldekranz.com>,
	Claudiu Manoil <claudiu.manoil@nxp.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	Roopa Prabhu <roopa@nvidia.com>,
	Nikolay Aleksandrov <nikolay@nvidia.com>,
	Jiri Pirko <jiri@resnulli.us>, Ido Schimmel <idosch@idosch.org>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	UNGLinuxDriver@microchip.com, Ivan Vecera <ivecera@redhat.com>,
	linux-omap@vger.kernel.org,
	Vladimir Oltean <vladimir.oltean@nxp.com>
Subject: [PATCH v4 net-next 04/11] net: bridge: add helper to replay port and local fdb entries
Date: Tue, 23 Mar 2021 01:51:45 +0200
Message-ID: <20210322235152.268695-5-olteanv@gmail.com> (raw)
In-Reply-To: <20210322235152.268695-1-olteanv@gmail.com>

From: Vladimir Oltean <vladimir.oltean@nxp.com>

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

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

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

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

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

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

Reported-by: Ido Schimmel <idosch@idosch.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 include/linux/if_bridge.h |  9 +++++++
 net/bridge/br_fdb.c       | 50 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index f6472969bb44..b564c4486a45 100644
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -147,6 +147,8 @@ void br_fdb_clear_offload(const struct net_device *dev, u16 vid);
 bool br_port_flag_is_set(const struct net_device *dev, unsigned long flag);
 u8 br_port_get_stp_state(const struct net_device *dev);
 clock_t br_get_ageing_time(struct net_device *br_dev);
+int br_fdb_replay(struct net_device *br_dev, struct net_device *dev,
+		  struct notifier_block *nb);
 #else
 static inline struct net_device *
 br_fdb_find_port(const struct net_device *br_dev,
@@ -175,6 +177,13 @@ static inline clock_t br_get_ageing_time(struct net_device *br_dev)
 {
 	return 0;
 }
+
+static inline int br_fdb_replay(struct net_device *br_dev,
+				struct net_device *dev,
+				struct notifier_block *nb)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 
 #endif
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index b7490237f3fc..698b79747d32 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -726,6 +726,56 @@ static inline size_t fdb_nlmsg_size(void)
 		+ nla_total_size(sizeof(u8)); /* NFEA_ACTIVITY_NOTIFY */
 }
 
+static int br_fdb_replay_one(struct notifier_block *nb,
+			     struct net_bridge_fdb_entry *fdb,
+			     struct net_device *dev)
+{
+	struct switchdev_notifier_fdb_info item;
+	int err;
+
+	item.addr = fdb->key.addr.addr;
+	item.vid = fdb->key.vlan_id;
+	item.added_by_user = test_bit(BR_FDB_ADDED_BY_USER, &fdb->flags);
+	item.offloaded = test_bit(BR_FDB_OFFLOADED, &fdb->flags);
+	item.info.dev = dev;
+
+	err = nb->notifier_call(nb, SWITCHDEV_FDB_ADD_TO_DEVICE, &item);
+	return notifier_to_errno(err);
+}
+
+int br_fdb_replay(struct net_device *br_dev, struct net_device *dev,
+		  struct notifier_block *nb)
+{
+	struct net_bridge_fdb_entry *fdb;
+	struct net_bridge *br;
+	int err = 0;
+
+	if (!netif_is_bridge_master(br_dev) || !netif_is_bridge_port(dev))
+		return -EINVAL;
+
+	br = netdev_priv(br_dev);
+
+	rcu_read_lock();
+
+	hlist_for_each_entry_rcu(fdb, &br->fdb_list, fdb_node) {
+		struct net_bridge_port *dst = READ_ONCE(fdb->dst);
+		struct net_device *dst_dev;
+
+		dst_dev = dst ? dst->dev : br->dev;
+		if (dst_dev != br_dev && dst_dev != dev)
+			continue;
+
+		err = br_fdb_replay_one(nb, fdb, dst_dev);
+		if (err)
+			break;
+	}
+
+	rcu_read_unlock();
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(br_fdb_replay);
+
 static void fdb_notify(struct net_bridge *br,
 		       const struct net_bridge_fdb_entry *fdb, int type,
 		       bool swdev_notify)
-- 
2.25.1


  parent reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-22 23:51 [PATCH v4 net-next 00/11] Better support for sandwiched LAGs with bridge and DSA Vladimir Oltean
2021-03-22 23:51 ` [PATCH v4 net-next 01/11] net: bridge: add helper for retrieving the current bridge port STP state Vladimir Oltean
2021-03-23 10:33   ` Nikolay Aleksandrov
2021-03-22 23:51 ` [PATCH v4 net-next 02/11] net: bridge: add helper to retrieve the current ageing time Vladimir Oltean
2021-03-23 10:36   ` Nikolay Aleksandrov
2021-03-22 23:51 ` [PATCH v4 net-next 03/11] net: bridge: add helper to replay port and host-joined mdb entries Vladimir Oltean
2021-03-23 12:00   ` Nikolay Aleksandrov
2021-03-22 23:51 ` Vladimir Oltean [this message]
2021-03-23 11:12   ` [PATCH v4 net-next 04/11] net: bridge: add helper to replay port and local fdb entries Nikolay Aleksandrov
2021-03-23 18:11     ` Vladimir Oltean
2021-03-22 23:51 ` [PATCH v4 net-next 05/11] net: bridge: add helper to replay VLANs installed on port Vladimir Oltean
2021-03-23 14:06   ` Nikolay Aleksandrov
2021-03-22 23:51 ` [PATCH v4 net-next 06/11] net: dsa: call dsa_port_bridge_join when joining a LAG that is already in a bridge Vladimir Oltean
2021-03-22 23:51 ` [PATCH v4 net-next 07/11] net: dsa: pass extack to dsa_port_{bridge,lag}_join Vladimir Oltean
2021-03-22 23:51 ` [PATCH v4 net-next 08/11] net: dsa: inherit the actual bridge port flags at join time Vladimir Oltean
2021-03-22 23:51 ` [PATCH v4 net-next 09/11] net: dsa: sync up switchdev objects and port attributes when joining the bridge Vladimir Oltean
2021-03-22 23:51 ` [PATCH v4 net-next 10/11] net: ocelot: call ocelot_netdevice_bridge_join when joining a bridged LAG Vladimir Oltean
2021-03-22 23:51 ` [PATCH v4 net-next 11/11] net: ocelot: replay switchdev events when joining bridge Vladimir Oltean
2021-03-23 22:00 ` [PATCH v4 net-next 00/11] Better support for sandwiched LAGs with bridge and DSA patchwork-bot+netdevbpf

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