From: Antonio Quartulli <antonio(a)open-mesh.com>
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(a)open-mesh.com>
---
Changes since v3:
- always re-add NO_PURGE local entry on add_vid()
Changes since v2:
- remove cleanup_work member that is not needed anymore in this approach
- reword commit subject
- reword commit message (Thanks Marek!)
Changes since v1:
- destroy and create vlan sysfs folder within softif_vlan_destroy/create() to
avoid lock troubles with soft-interface destruction and delayed jobs.
soft-interface.c | 53 ++++++++++++++++++++++++++++++++++++++++-------------
translation-table.c | 26 ++++++++++++++++++++++++++
types.h | 2 ++
3 files changed, 68 insertions(+), 13 deletions(-)
diff --git a/soft-interface.c b/soft-interface.c
index d962363..321c6bd 100644
--- a/soft-interface.c
+++ b/soft-interface.c
@@ -437,10 +437,15 @@ 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);
+ }
}
/**
@@ -494,6 +499,7 @@ 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);
@@ -505,6 +511,10 @@ 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
*/
@@ -512,10 +522,6 @@ 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;
}
@@ -527,18 +533,13 @@ 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);
}
@@ -556,6 +557,8 @@ 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
@@ -565,6 +568,30 @@ static int batadv_interface_add_vid(struct net_device *dev, __be16 proto,
vid |= BATADV_VLAN_HAS_TAG;
+ /* if a new vlan is getting created, but it is found in the list, it
+ * means that it was not deleted yet. Make batadv_softif_vlan_get()
+ * increase the refcounter by one and return
+ */
+ vlan = batadv_softif_vlan_get(bat_priv, vid);
+ if (vlan) {
+ /* 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);
+ ret = 0;
+ if (!vlan->kobj) {
+ ret = batadv_sysfs_add_vlan(bat_priv->soft_iface, vlan);
+ if (ret)
+ batadv_softif_vlan_free_ref(vlan);
+ }
+
+ return ret;
+ }
+
return batadv_softif_create_vlan(bat_priv, vid);
}
diff --git a/translation-table.c b/translation-table.c
index 959dde7..b689981 100644
--- a/translation-table.c
+++ b/translation-table.c
@@ -485,6 +485,7 @@ 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;
+ struct batadv_softif_vlan *vlan;
struct net_device *in_dev = NULL;
struct hlist_head *head;
struct batadv_tt_orig_list_entry *orig_entry;
@@ -544,6 +545,9 @@ 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),
@@ -573,6 +577,7 @@ 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;
}
@@ -978,6 +983,7 @@ 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)
@@ -1008,6 +1014,11 @@ 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);
@@ -1080,6 +1091,7 @@ 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;
@@ -1100,6 +1112,13 @@ 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);
@@ -3078,6 +3097,7 @@ 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 */
@@ -3106,6 +3126,12 @@ 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);
diff --git a/types.h b/types.h
index 78370ab..c4aba2f 100644
--- a/types.h
+++ b/types.h
@@ -638,6 +638,7 @@ 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
@@ -647,6 +648,7 @@ 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 */
--
1.8.3.2