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net: bridge: move default pvid init/deinit to NETDEV_REGISTER/UNREGISTER

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Most of the bridge device's vlan init bugs come from the fact that its
default pvid is created at the wrong time, way too early in ndo_init()
before the device is even assigned an ifindex. It introduces a bug when the
bridge's dev_addr is added as fdb during the initial default pvid creation
the notification has ifindex/NDA_MASTER both equal to 0 (see example below)
which really makes no sense for user-space[0] and is wrong.
Usually user-space software would ignore such entries, but they are
actually valid and will eventually have all necessary attributes.
It makes much more sense to send a notification *after* the device has
registered and has a proper ifindex allocated rather than before when
there's a chance that the registration might still fail or to receive
it with ifindex/NDA_MASTER == 0. Note that we can remove the fdb flush
from br_vlan_flush() since that case can no longer happen. At
NETDEV_REGISTER br->default_pvid is always == 1 as it's initialized by
br_vlan_init() before that and at NETDEV_UNREGISTER it can be anything
depending why it was called (if called due to NETDEV_REGISTER error
it'll still be == 1, otherwise it could be any value changed during the
device life time).

For the demonstration below a small change to iproute2 for printing all fdb
notifications is added, because it contained a workaround not to show
entries with ifindex == 0.
Command executed while monitoring: $ ip l add br0 type bridge
Before (both ifindex and master == 0):
$ bridge monitor fdb
36:7e:8a:b3:56:ba dev * vlan 1 master * permanent

After (proper br0 ifindex):
$ bridge monitor fdb
e6:2a:ae:7a:b7:48 dev br0 vlan 1 master br0 permanent

v4: move only the default pvid init/deinit to NETDEV_REGISTER/UNREGISTER
v3: send the correct v2 patch with all changes (stub should return 0)
v2: on error in br_vlan_init set br->vlgrp to NULL and return 0 in
    the br_vlan_bridge_event stub when bridge vlans are disabled

[0] https://bugzilla.kernel.org/show_bug.cgi?id=204389

Reported-by: michael-dev <michael-dev@fami-braun.de>
Fixes: 5be5a2df40 ("bridge: Add filtering support for default_pvid")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Nikolay Aleksandrov
2019-08-02 13:57:36 +03:00
committed by David S. Miller
parent d934423ac2
commit 091adf9ba6
3 changed files with 25 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
net/bridge/br_private.h
View File

@@ -894,8 +894,8 @@ int nbp_get_num_vlan_infos(struct net_bridge_port *p, u32 filter_mask);
void br_vlan_get_stats(const struct net_bridge_vlan *v,
struct br_vlan_stats *stats);
void br_vlan_port_event(struct net_bridge_port *p, unsigned long event);
void br_vlan_bridge_event(struct net_device *dev, unsigned long event,
void *ptr);
int br_vlan_bridge_event(struct net_device *dev, unsigned long event,
void *ptr);
static inline struct net_bridge_vlan_group *br_vlan_group(
const struct net_bridge *br)
@@ -1085,9 +1085,10 @@ static inline void br_vlan_port_event(struct net_bridge_port *p,
{
}
static inline void br_vlan_bridge_event(struct net_device *dev,
unsigned long event, void *ptr)
static inline int br_vlan_bridge_event(struct net_device *dev,
unsigned long event, void *ptr)
{
return 0;
}
#endif