From 35df3b298fc8779f7edf4b0228c683f7e98edcd5 Mon Sep 17 00:00:00 2001 From: Antonio Quartulli Date: Thu, 8 May 2014 17:13:15 +0200 Subject: 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: Antonio Quartulli Signed-off-by: Marek Lindner --- net/batman-adv/soft-interface.c | 60 +++++++++++++++++++++++++++++++---------- 1 file changed, 46 insertions(+), 14 deletions(-) (limited to 'net/batman-adv/soft-interface.c') diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index e7ee65d..cbd677f 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -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; - 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; } /** -- cgit v1.1