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Commit 35df3b29 authored by Antonio Quartulli's avatar Antonio Quartulli Committed by Antonio Quartulli
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batman-adv: fix TT VLAN inconsistency on VLAN re-add 



When a VLAN interface (on top of batX) is removed and
re-added within a short timeframe TT does not have enough
time to properly cleanup. This creates an internal TT state
mismatch as the newly created softif_vlan will be
initialized from scratch with a TT client count of zero
(even if TT entries for this VLAN still exist). The
resulting TT messages are bogus due to the counter / tt
client listing mismatch, thus creating inconsistencies on
every node in the network

To fix this issue destroy_vlan() has to not free the VLAN
object immediately but it has to be kept alive until all the
TT entries for this VLAN have been removed. destroy_vlan()
still removes the sysfs folder so that the user has the
feeling that everything went fine.

If the same VLAN is re-added before the old object is free'd,
then the latter is resurrected and re-used.

Implement such behaviour by increasing the reference counter
of a softif_vlan object every time a new local TT entry for
such VLAN is created and remove the object from the list
only when all the TT entries have been destroyed.

Signed-off-by: default avatarAntonio Quartulli <antonio@open-mesh.com>
Signed-off-by: default avatarMarek Lindner <mareklindner@neomailbox.ch>
parent d46b6bfa

net/batman-adv/soft-interface.c

+46 −14
Original line number Diff line number Diff line
@@ -448,10 +448,15 @@ out: 
 *  possibly free it

 * @softif_vlan: the vlan object to release

 */

void batadv_softif_vlan_free_ref(struct batadv_softif_vlan *softif_vlan)

void batadv_softif_vlan_free_ref(struct batadv_softif_vlan *vlan)

{

	if (atomic_dec_and_test(&softif_vlan->refcount))

		kfree_rcu(softif_vlan, rcu);

	if (atomic_dec_and_test(&vlan->refcount)) {

		spin_lock_bh(&vlan->bat_priv->softif_vlan_list_lock);

		hlist_del_rcu(&vlan->list);

		spin_unlock_bh(&vlan->bat_priv->softif_vlan_list_lock);



		kfree_rcu(vlan, rcu);

	}

}



/**
@@ -505,6 +510,7 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid) 
	if (!vlan)

		return -ENOMEM;



	vlan->bat_priv = bat_priv;

	vlan->vid = vid;

	atomic_set(&vlan->refcount, 1);
@@ -516,6 +522,10 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid) 
		return err;

	}



	spin_lock_bh(&bat_priv->softif_vlan_list_lock);

	hlist_add_head_rcu(&vlan->list, &bat_priv->softif_vlan_list);

	spin_unlock_bh(&bat_priv->softif_vlan_list_lock);



	/* add a new TT local entry. This one will be marked with the NOPURGE

	 * flag

	 */
@@ -523,10 +533,6 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid) 
			    bat_priv->soft_iface->dev_addr, vid,

			    BATADV_NULL_IFINDEX, BATADV_NO_MARK);



	spin_lock_bh(&bat_priv->softif_vlan_list_lock);

	hlist_add_head_rcu(&vlan->list, &bat_priv->softif_vlan_list);

	spin_unlock_bh(&bat_priv->softif_vlan_list_lock);



	return 0;

}
@@ -538,18 +544,13 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid) 
static void batadv_softif_destroy_vlan(struct batadv_priv *bat_priv,

				       struct batadv_softif_vlan *vlan)

{

	spin_lock_bh(&bat_priv->softif_vlan_list_lock);

	hlist_del_rcu(&vlan->list);

	spin_unlock_bh(&bat_priv->softif_vlan_list_lock);



	batadv_sysfs_del_vlan(bat_priv, vlan);



	/* explicitly remove the associated TT local entry because it is marked

	 * with the NOPURGE flag

	 */

	batadv_tt_local_remove(bat_priv, bat_priv->soft_iface->dev_addr,

			       vlan->vid, "vlan interface destroyed", false);



	batadv_sysfs_del_vlan(bat_priv, vlan);

	batadv_softif_vlan_free_ref(vlan);

}
@@ -567,6 +568,8 @@ static int batadv_interface_add_vid(struct net_device *dev, __be16 proto, 
				    unsigned short vid)

{

	struct batadv_priv *bat_priv = netdev_priv(dev);

	struct batadv_softif_vlan *vlan;

	int ret;



	/* only 802.1Q vlans are supported.

	 * batman-adv does not know how to handle other types
@@ -576,7 +579,36 @@ static int batadv_interface_add_vid(struct net_device *dev, __be16 proto, 


	vid |= BATADV_VLAN_HAS_TAG;



	/* if a new vlan is getting created and it already exists, it means that

	 * it was not deleted yet. batadv_softif_vlan_get() increases the

	 * refcount in order to revive the object.

	 *

	 * if it does not exist then create it.

	 */

	vlan = batadv_softif_vlan_get(bat_priv, vid);

	if (!vlan)

		return batadv_softif_create_vlan(bat_priv, vid);



	/* recreate the sysfs object if it was already destroyed (and it should

	 * be since we received a kill_vid() for this vlan

	 */

	if (!vlan->kobj) {

		ret = batadv_sysfs_add_vlan(bat_priv->soft_iface, vlan);

		if (ret) {

			batadv_softif_vlan_free_ref(vlan);

			return ret;

		}

	}



	/* add a new TT local entry. This one will be marked with the NOPURGE

	 * flag. This must be added again, even if the vlan object already

	 * exists, because the entry was deleted by kill_vid()

	 */

	batadv_tt_local_add(bat_priv->soft_iface,

			    bat_priv->soft_iface->dev_addr, vid,

			    BATADV_NULL_IFINDEX, BATADV_NO_MARK);



	return 0;

}



/**

net/batman-adv/translation-table.c

+26 −0
Original line number Diff line number Diff line
@@ -511,6 +511,7 @@ bool batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr, 
	struct batadv_priv *bat_priv = netdev_priv(soft_iface);

	struct batadv_tt_local_entry *tt_local;

	struct batadv_tt_global_entry *tt_global = NULL;

	struct batadv_softif_vlan *vlan;

	struct net_device *in_dev = NULL;

	struct hlist_head *head;

	struct batadv_tt_orig_list_entry *orig_entry;
@@ -572,6 +573,9 @@ bool batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr, 
	if (!tt_local)

		goto out;



	/* increase the refcounter of the related vlan */

	vlan = batadv_softif_vlan_get(bat_priv, vid);



	batadv_dbg(BATADV_DBG_TT, bat_priv,

		   "Creating new local tt entry: %pM (vid: %d, ttvn: %d)\n",

		   addr, BATADV_PRINT_VID(vid),
@@ -604,6 +608,7 @@ bool batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr, 
	if (unlikely(hash_added != 0)) {

		/* remove the reference for the hash */

		batadv_tt_local_entry_free_ref(tt_local);

		batadv_softif_vlan_free_ref(vlan);

		goto out;

	}
@@ -1009,6 +1014,7 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv, 
{

	struct batadv_tt_local_entry *tt_local_entry;

	uint16_t flags, curr_flags = BATADV_NO_FLAGS;

	struct batadv_softif_vlan *vlan;



	tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr, vid);

	if (!tt_local_entry)
@@ -1039,6 +1045,11 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv, 
	hlist_del_rcu(&tt_local_entry->common.hash_entry);

	batadv_tt_local_entry_free_ref(tt_local_entry);



	/* decrease the reference held for this vlan */

	vlan = batadv_softif_vlan_get(bat_priv, vid);

	batadv_softif_vlan_free_ref(vlan);

	batadv_softif_vlan_free_ref(vlan);



out:

	if (tt_local_entry)

		batadv_tt_local_entry_free_ref(tt_local_entry);
@@ -1111,6 +1122,7 @@ static void batadv_tt_local_table_free(struct batadv_priv *bat_priv) 
	spinlock_t *list_lock; /* protects write access to the hash lists */

	struct batadv_tt_common_entry *tt_common_entry;

	struct batadv_tt_local_entry *tt_local;

	struct batadv_softif_vlan *vlan;

	struct hlist_node *node_tmp;

	struct hlist_head *head;

	uint32_t i;
@@ -1131,6 +1143,13 @@ static void batadv_tt_local_table_free(struct batadv_priv *bat_priv) 
			tt_local = container_of(tt_common_entry,

						struct batadv_tt_local_entry,

						common);



			/* decrease the reference held for this vlan */

			vlan = batadv_softif_vlan_get(bat_priv,

						      tt_common_entry->vid);

			batadv_softif_vlan_free_ref(vlan);

			batadv_softif_vlan_free_ref(vlan);



			batadv_tt_local_entry_free_ref(tt_local);

		}

		spin_unlock_bh(list_lock);
@@ -3139,6 +3158,7 @@ static void batadv_tt_local_purge_pending_clients(struct batadv_priv *bat_priv) 
	struct batadv_hashtable *hash = bat_priv->tt.local_hash;

	struct batadv_tt_common_entry *tt_common;

	struct batadv_tt_local_entry *tt_local;

	struct batadv_softif_vlan *vlan;

	struct hlist_node *node_tmp;

	struct hlist_head *head;

	spinlock_t *list_lock; /* protects write access to the hash lists */
@@ -3167,6 +3187,12 @@ static void batadv_tt_local_purge_pending_clients(struct batadv_priv *bat_priv) 
			tt_local = container_of(tt_common,

						struct batadv_tt_local_entry,

						common);



			/* decrease the reference held for this vlan */

			vlan = batadv_softif_vlan_get(bat_priv, tt_common->vid);

			batadv_softif_vlan_free_ref(vlan);

			batadv_softif_vlan_free_ref(vlan);



			batadv_tt_local_entry_free_ref(tt_local);

		}

		spin_unlock_bh(list_lock);

net/batman-adv/types.h

+2 −0
Original line number Diff line number Diff line
@@ -687,6 +687,7 @@ struct batadv_priv_nc { 


/**

 * struct batadv_softif_vlan - per VLAN attributes set

 * @bat_priv: pointer to the mesh object

 * @vid: VLAN identifier

 * @kobj: kobject for sysfs vlan subdirectory

 * @ap_isolation: AP isolation state
@@ -696,6 +697,7 @@ struct batadv_priv_nc { 
 * @rcu: struct used for freeing in a RCU-safe manner

 */

struct batadv_softif_vlan {

	struct batadv_priv *bat_priv;

	unsigned short vid;

	struct kobject *kobj;

	atomic_t ap_isolation;		/* boolean */