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Commit 091adf9b authored by Nikolay Aleksandrov's avatar Nikolay Aleksandrov Committed by David S. Miller
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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: default avatarmichael-dev <michael-dev@fami-braun.de>
Fixes: 5be5a2df ("bridge: Add filtering support for default_pvid")
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: default avatarRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d934423a

net/bridge/br.c

+4 −1
Original line number Diff line number Diff line
@@ -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 */

net/bridge/br_private.h

+5 −4
Original line number Diff line number Diff line
@@ -894,7 +894,7 @@ 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,

int br_vlan_bridge_event(struct net_device *dev, unsigned long event,

			 void *ptr);



static inline struct net_bridge_vlan_group *br_vlan_group(
@@ -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,

static inline int br_vlan_bridge_event(struct net_device *dev,

				       unsigned long event, void *ptr)

{

	return 0;

}

#endif

net/bridge/br_vlan.c

+16 −18
Original line number Diff line number Diff line
@@ -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. */