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batman-adv: fix TT VLAN inconsistency on VLAN re-add
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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: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
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@ordex
ordex committed Jul 21, 2014
1 parent d46b6bf commit 35df3b2
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Showing 3 changed files with 74 additions and 14 deletions.
60 changes: 46 additions & 14 deletions net/batman-adv/soft-interface.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -448,10 +448,15 @@ void batadv_interface_rx(struct net_device *soft_iface,
* 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);
}
}

/**
Expand Down Expand Up @@ -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);

Expand All @@ -516,17 +522,17 @@ 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
*/
batadv_tt_local_add(bat_priv->soft_iface,
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;
}

Expand All @@ -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);
}

Expand All @@ -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
Expand All @@ -576,7 +579,36 @@ static int batadv_interface_add_vid(struct net_device *dev, __be16 proto,

vid |= BATADV_VLAN_HAS_TAG;

return batadv_softif_create_vlan(bat_priv, vid);
/* 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;
}

/**
Expand Down
26 changes: 26 additions & 0 deletions net/batman-adv/translation-table.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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),
Expand Down Expand Up @@ -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;
}

Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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;
Expand All @@ -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);
Expand Down Expand Up @@ -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 */
Expand Down Expand Up @@ -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);
Expand Down
2 changes: 2 additions & 0 deletions net/batman-adv/types.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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 */
Expand Down

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