6.6-stable review patch. If anyone has any objections, please let me know.
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From: Petr Machata petrm@nvidia.com
[ Upstream commit cd9a9562b2559973aa1b68c3af63021a2c5fd022 ]
Currently, after the bridge is created, the FDB does not hold an FDB entry for the bridge MAC on VLAN 0:
# ip link add name br up type bridge # ip -br link show dev br br UNKNOWN 92:19:8c:4e:01:ed <BROADCAST,MULTICAST,UP,LOWER_UP> # bridge fdb show | grep 92:19:8c:4e:01:ed 92:19:8c:4e:01:ed dev br vlan 1 master br permanent
Later when the bridge MAC is changed, or in fact when the address is given during netdevice creation, the entry appears:
# ip link add name br up address 00:11:22:33:44:55 type bridge # bridge fdb show | grep 00:11:22:33:44:55 00:11:22:33:44:55 dev br vlan 1 master br permanent 00:11:22:33:44:55 dev br master br permanent
However when the bridge address is set by the user to the current bridge address before the first port is enslaved, none of the address handlers gets invoked, because the address is not actually changed. The address is however marked as NET_ADDR_SET. Then when a port is enslaved, the address is not changed, because it is NET_ADDR_SET. Thus the VLAN 0 entry is not added, and it has not been added previously either:
# ip link add name br up type bridge # ip -br link show dev br br UNKNOWN 7e:f0:a8:1a:be:c2 <BROADCAST,MULTICAST,UP,LOWER_UP> # ip link set dev br addr 7e:f0:a8:1a:be:c2 # ip link add name v up type veth # ip link set dev v master br # ip -br link show dev br br UNKNOWN 7e:f0:a8:1a:be:c2 <BROADCAST,MULTICAST,UP,LOWER_UP> # bridge fdb | grep 7e:f0:a8:1a:be:c2 7e:f0:a8:1a:be:c2 dev br vlan 1 master br permanent
Then when the bridge MAC is used as DMAC, and br_handle_frame_finish() looks up an FDB entry with VLAN=0, it doesn't find any, and floods the traffic instead of passing it up.
Fix this by simply adding the VLAN 0 FDB entry for the bridge itself always on netdevice creation. This also makes the behavior consistent with how ports are treated: ports always have an FDB entry for each member VLAN as well as VLAN 0.
Signed-off-by: Petr Machata petrm@nvidia.com Reviewed-by: Ido Schimmel idosch@nvidia.com Acked-by: Nikolay Aleksandrov razor@blackwall.org Link: https://patch.msgid.link/415202b2d1b9b0899479a502bbe2ba188678f192.1758550408... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/bridge/br.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/net/bridge/br.c b/net/bridge/br.c index a45db67197226..d466febcf9abe 100644 --- a/net/bridge/br.c +++ b/net/bridge/br.c @@ -37,6 +37,11 @@ static int br_device_event(struct notifier_block *unused, unsigned long event, v int err;
if (netif_is_bridge_master(dev)) { + struct net_bridge *br = netdev_priv(dev); + + if (event == NETDEV_REGISTER) + br_fdb_change_mac_address(br, dev->dev_addr); + err = br_vlan_bridge_event(dev, event, ptr); if (err) return notifier_from_errno(err);