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

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>

diff --git a/net/bridge/br.c b/net/bridge/br.c
index d164f63a4345c5667e5190f92900d79d3d8806d8..8a8f9e5f264f2a70b246094fa7c31f1be8c0deef 100644 (file)
--- a/net/bridge/br.c
+++ b/net/bridge/br.c
@@ -37,12 +37,15 @@ static int br_device_event(struct notifier_block *unused, unsigned long event, v
        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 */

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index e8cf03b43b7d6c5225f6be08d285a2cbe0307fa2..646504db0220eaadf112a14a82a56f5223d264fa 100644 (file)
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -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
 

diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index a544e161c7fa3cc5a08c7b0f8cfa8884e49a6e4e..f5b2aeebbfe98d82a084c78be2747a14ebcbc938 100644 (file)
--- 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);
@@ -1058,7 +1053,6 @@ 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)
@@ -1073,17 +1067,10 @@ 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:
@@ -1469,13 +1456,23 @@ static void nbp_vlan_set_vlan_dev_state(struct net_bridge_port *p, u16 vid)
 }
 
 /* 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);
@@ -1483,12 +1480,13 @@ void br_vlan_bridge_event(struct net_device *dev, unsigned long event,
 
        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. */