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Subject[PATCH 5.2 20/56] net: bridge: move default pvid init/deinit to NETDEV_REGISTER/UNREGISTER
Date
From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>

[ Upstream commit 091adf9ba6cdb432cbcc217b47e4ffb8aa0d8865 ]

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: 5be5a2df40f0 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/bridge/br.c | 5 ++++-
net/bridge/br_private.h | 9 +++++----
net/bridge/br_vlan.c | 34 ++++++++++++++++------------------
3 files changed, 25 insertions(+), 23 deletions(-)

--- a/net/bridge/br.c
+++ b/net/bridge/br.c
@@ -37,12 +37,15 @@ static int br_device_event(struct notifi
int err;

if (dev->priv_flags & IFF_EBRIDGE) {
+ err = br_vlan_bridge_event(dev, event, ptr);
+ if (err)
+ return notifier_from_errno(err);
+
if (event == NETDEV_REGISTER) {
/* register of bridge completed, add sysfs entries */
br_sysfs_addbr(dev);
return NOTIFY_DONE;
}
- br_vlan_bridge_event(dev, event, ptr);
}

/* not a port of a bridge */
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -893,8 +893,8 @@ int nbp_get_num_vlan_infos(struct net_br
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)
@@ -1084,9 +1084,10 @@ static inline void br_vlan_port_event(st
{
}

-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

--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -715,11 +715,6 @@ void br_vlan_flush(struct net_bridge *br

ASSERT_RTNL();

- /* delete auto-added default pvid local fdb before flushing vlans
- * otherwise it will be leaked on bridge device init failure
- */
- br_fdb_delete_by_port(br, NULL, 0, 1);
-
vg = br_vlan_group(br);
__vlan_flush(vg);
RCU_INIT_POINTER(br->vlgrp, NULL);
@@ -1048,7 +1043,6 @@ int br_vlan_init(struct net_bridge *br)
{
struct net_bridge_vlan_group *vg;
int ret = -ENOMEM;
- bool changed;

vg = kzalloc(sizeof(*vg), GFP_KERNEL);
if (!vg)
@@ -1063,17 +1057,10 @@ int br_vlan_init(struct net_bridge *br)
br->vlan_proto = htons(ETH_P_8021Q);
br->default_pvid = 1;
rcu_assign_pointer(br->vlgrp, vg);
- ret = br_vlan_add(br, 1,
- BRIDGE_VLAN_INFO_PVID | BRIDGE_VLAN_INFO_UNTAGGED |
- BRIDGE_VLAN_INFO_BRENTRY, &changed, NULL);
- if (ret)
- goto err_vlan_add;

out:
return ret;

-err_vlan_add:
- vlan_tunnel_deinit(vg);
err_tunnel_init:
rhashtable_destroy(&vg->vlan_hash);
err_rhtbl:
@@ -1448,13 +1435,23 @@ static void nbp_vlan_set_vlan_dev_state(
}

/* Must be protected by RTNL. */
-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)
{
struct netdev_notifier_changeupper_info *info;
- struct net_bridge *br;
+ struct net_bridge *br = netdev_priv(dev);
+ bool changed;
+ int ret = 0;

switch (event) {
+ case NETDEV_REGISTER:
+ ret = br_vlan_add(br, br->default_pvid,
+ BRIDGE_VLAN_INFO_PVID |
+ BRIDGE_VLAN_INFO_UNTAGGED |
+ BRIDGE_VLAN_INFO_BRENTRY, &changed, NULL);
+ break;
+ case NETDEV_UNREGISTER:
+ br_vlan_delete(br, br->default_pvid);
+ break;
case NETDEV_CHANGEUPPER:
info = ptr;
br_vlan_upper_change(dev, info->upper_dev, info->linking);
@@ -1462,12 +1459,13 @@ void br_vlan_bridge_event(struct net_dev

case NETDEV_CHANGE:
case NETDEV_UP:
- br = netdev_priv(dev);
if (!br_opt_get(br, BROPT_VLAN_BRIDGE_BINDING))
- return;
+ break;
br_vlan_link_state_change(dev, br);
break;
}
+
+ return ret;
}

/* Must be protected by RTNL. */

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