[B.A.T.M.A.N.] [PATCHv5 1/2] batman-adv: add per VLAN interface attribute framework

[B.A.T.M.A.N.] [PATCHv5 1/2] batman-adv: add per VLAN interface attribute framework

[Antonio Quartulli]

From: Antonio Quartulli <antonio@open-mesh.com>

Since batman-adv is now fully VLAN-aware, a proper framework
able to handle per-vlan-interface attributes is needed.

Those attributes will affect the associated VLAN interface
only, rather than the real soft_iface (which would result
in every vlan interface having the same attribute
configuration)

To make the code simpler and easier to extend, attributes
associated to the standalone soft_iface are now treated
like belonging to yet another vlan having a special vid.
This vid is different from the others because it is made up
by all zeros and the VLAN_HAS_TAG bit is not set.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
---


v5:
- tt-vlan patchset has been divided in several small patchsets (this is the
  first one)
- change about bat0 being treated like another vlan has been merged in this
  patch
- patch anticipating sysfs creation has been dropped. It could lead to race
  conditions




 compat.c         |   9 ++++
 compat.h         |  24 +++++++++
 hard-interface.c |   2 +
 main.c           |   5 +-
 soft-interface.c | 145 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 soft-interface.h |   1 +
 types.h          |  21 ++++++++
 7 files changed, 204 insertions(+), 3 deletions(-)

diff --git a/compat.c b/compat.c
index da556a4..0a98fb7 100644
--- a/compat.c
+++ b/compat.c
@@ -27,6 +27,15 @@
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 0, 0)
 
+void batadv_free_rcu_softif_vlan(struct rcu_head *rcu)
+{
+	struct batadv_softif_vlan *vlan;
+
+	vlan = container_of(rcu, struct batadv_softif_vlan, rcu);
+
+	kfree(vlan);
+}
+
 void batadv_free_rcu_tt_global_entry(struct rcu_head *rcu)
 {
 	struct batadv_tt_global_entry *global;
diff --git a/compat.h b/compat.h
index dbf1926..1ee0467 100644
--- a/compat.h
+++ b/compat.h
@@ -182,6 +182,7 @@ static const struct { \
 #define kfree_rcu(ptr, rcu_head) call_rcu(&ptr->rcu_head, batadv_free_rcu_##ptr)
 #define vlan_insert_tag(skb, proto, vid) __vlan_put_tag(skb, vid)
 
+void batadv_free_rcu_softif_vlan(struct rcu_head *rcu);
 void batadv_free_rcu_tt_global_entry(struct rcu_head *rcu);
 void batadv_free_rcu_gw_node(struct rcu_head *rcu);
 void batadv_free_rcu_neigh_node(struct rcu_head *rcu);
@@ -300,6 +301,29 @@ static int __batadv_interface_set_mac_addr(x, y)
 #include <linux/if_vlan.h>
 #define vlan_insert_tag(skb, proto, vid) vlan_insert_tag(skb, vid)
 
+#define NETIF_F_HW_VLAN_CTAG_FILTER NETIF_F_HW_VLAN_FILTER
+
+#define batadv_interface_add_vid(x, y, z) \
+__batadv_interface_add_vid(struct net_device *dev, __be16 proto,\
+			   unsigned short vid);\
+static int batadv_interface_add_vid(struct net_device *dev, unsigned short vid)\
+{\
+	return __batadv_interface_add_vid(dev, htons(ETH_P_8021Q), vid);\
+} \
+static int __batadv_interface_add_vid(struct net_device *dev, __be16 proto,\
+				      unsigned short vid)
+
+#define batadv_interface_kill_vid(x, y, z) \
+__batadv_interface_kill_vid(struct net_device *dev, __be16 proto,\
+			    unsigned short vid);\
+static int batadv_interface_kill_vid(struct net_device *dev,\
+				     unsigned short vid)\
+{\
+	return __batadv_interface_kill_vid(dev, htons(ETH_P_8021Q), vid);\
+} \
+static int __batadv_interface_kill_vid(struct net_device *dev, __be16 proto,\
+				       unsigned short vid)
+
 #endif /* vlan_insert_tag */
 
 #endif /* < KERNEL_VERSION(3, 10, 0) */
diff --git a/hard-interface.c b/hard-interface.c
index d564af2..c5f871f 100644
--- a/hard-interface.c
+++ b/hard-interface.c
@@ -643,6 +643,8 @@ static int batadv_hard_if_event(struct notifier_block *this,
 
 	if (batadv_softif_is_valid(net_dev) && event == NETDEV_REGISTER) {
 		batadv_sysfs_add_meshif(net_dev);
+		bat_priv = netdev_priv(net_dev);
+		batadv_softif_create_vlan(bat_priv, BATADV_NO_FLAGS);
 		return NOTIFY_DONE;
 	}
 
diff --git a/main.c b/main.c
index f2f1137..fd7fac0 100644
--- a/main.c
+++ b/main.c
@@ -109,6 +109,7 @@ int batadv_mesh_init(struct net_device *soft_iface)
 	spin_lock_init(&bat_priv->gw.list_lock);
 	spin_lock_init(&bat_priv->tvlv.container_list_lock);
 	spin_lock_init(&bat_priv->tvlv.handler_list_lock);
+	spin_lock_init(&bat_priv->softif_vlan_list_lock);
 
 	INIT_HLIST_HEAD(&bat_priv->forw_bat_list);
 	INIT_HLIST_HEAD(&bat_priv->forw_bcast_list);
@@ -118,6 +119,7 @@ int batadv_mesh_init(struct net_device *soft_iface)
 	INIT_LIST_HEAD(&bat_priv->tt.roam_list);
 	INIT_HLIST_HEAD(&bat_priv->tvlv.container_list);
 	INIT_HLIST_HEAD(&bat_priv->tvlv.handler_list);
+	INIT_LIST_HEAD(&bat_priv->softif_vlan_list);
 
 	ret = batadv_originator_init(bat_priv);
 	if (ret < 0)
@@ -127,9 +129,6 @@ int batadv_mesh_init(struct net_device *soft_iface)
 	if (ret < 0)
 		goto err;
 
-	batadv_tt_local_add(soft_iface, soft_iface->dev_addr,
-			    BATADV_NULL_IFINDEX, BATADV_NO_FLAGS);
-
 	ret = batadv_bla_init(bat_priv);
 	if (ret < 0)
 		goto err;
diff --git a/soft-interface.c b/soft-interface.c
index d897194..f7552c5 100644
--- a/soft-interface.c
+++ b/soft-interface.c
@@ -384,6 +384,148 @@ out:
 	return;
 }
 
+/**
+ * batadv_softif_vlan_free_ref - decrease the vlan object refcounter and
+ *  possibly free it
+ * @softif_vlan: the vlan object to release
+ */
+static void batadv_softif_vlan_free_ref(struct batadv_softif_vlan *softif_vlan)
+{
+	if (atomic_dec_and_test(&softif_vlan->refcount))
+		kfree_rcu(softif_vlan, rcu);
+}
+
+/**
+ * batadv_softif_vlan_get - get the vlan object for a specific vid
+ * @bat_priv: the bat priv with all the soft interface information
+ * @vid: the identifier of the vlan object to retrieve
+ *
+ * Return the private data of the vlan matching the vid passed as argument or
+ * NULL otherwise. The refcounter of the returned object is incremented by 1.
+ */
+static struct batadv_softif_vlan *
+batadv_softif_vlan_get(struct batadv_priv *bat_priv, unsigned short vid)
+{
+	struct batadv_softif_vlan *vlan, *vlan_tmp = NULL;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(vlan, &bat_priv->softif_vlan_list, list) {
+		if (vlan->vid != vid)
+			continue;
+
+		if (!atomic_inc_not_zero(&vlan->refcount))
+			continue;
+
+		vlan_tmp = vlan;
+		break;
+	}
+	rcu_read_unlock();
+
+	return vlan_tmp;
+}
+
+/**
+ * batadv_create_vlan - allocate the needed resources for a new vlan
+ * @bat_priv: the bat priv with all the soft interface information
+ * @vid: the VLAN identifier
+ *
+ * Return 0 on success, a negative error otherwise.
+ */
+int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid)
+{
+	struct batadv_softif_vlan *vlan;
+
+	vlan = kzalloc(sizeof(*vlan), GFP_ATOMIC);
+	if (!vlan)
+		return -ENOMEM;
+
+	vlan->vid = vid;
+	atomic_set(&vlan->refcount, 1);
+
+	/* 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);
+
+	spin_lock_bh(&bat_priv->softif_vlan_list_lock);
+	list_add_rcu(&vlan->list, &bat_priv->softif_vlan_list);
+	spin_unlock_bh(&bat_priv->softif_vlan_list_lock);
+
+	return 0;
+}
+
+/**
+ * batadv_interface_add_vid - ndo_add_vid API implementation
+ * @dev: the netdev of the mesh interface
+ * @vid: identifier of the new vlan
+ *
+ * Set up all the internal structures for handling the new vlan on top of the
+ * mesh interface
+ *
+ * Return 0 on success or a negative error code in case of failure
+ */
+static int batadv_interface_add_vid(struct net_device *dev, __be16 proto,
+				    unsigned short vid)
+{
+	struct batadv_priv *bat_priv = netdev_priv(dev);
+
+	/* only 802.1Q vlans are supported.
+	 * batman-adv does not know how to handle other types
+	 */
+	if (proto != htons(ETH_P_8021Q))
+		return -EINVAL;
+
+	vid |= BATADV_VLAN_HAS_TAG;
+
+	return batadv_softif_create_vlan(bat_priv, vid);
+}
+
+/**
+ * batadv_interface_kill_vid - ndo_kill_vid API implementation
+ * @dev: the netdev of the mesh interface
+ * @vid: identifier of the deleted vlan
+ *
+ * Destroy all the internal structures used to handle the vlan identified by vid
+ * on top of the mesh interface
+ *
+ * Return 0 or -EINVAL if the specified prototype is not ETH_P_8021Q
+ */
+static int batadv_interface_kill_vid(struct net_device *dev, __be16 proto,
+				     unsigned short vid)
+{
+	struct batadv_priv *bat_priv = netdev_priv(dev);
+	struct batadv_softif_vlan *vlan;
+
+	/* only 802.1Q vlans are supported. batman-adv does not know how to
+	 * handle other types
+	 */
+	if (proto != htons(ETH_P_8021Q))
+		return -EINVAL;
+
+	vlan = batadv_softif_vlan_get(bat_priv, vid | BATADV_VLAN_HAS_TAG);
+	if (!vlan)
+		return -ENOENT;
+
+	spin_lock_bh(&bat_priv->softif_vlan_list_lock);
+	list_del_rcu(&vlan->list);
+	spin_unlock_bh(&bat_priv->softif_vlan_list_lock);
+
+	/* explicitly remove the associated TT local entry because it is marked
+	 * with the NOPURGE flag
+	 */
+	batadv_tt_local_remove(bat_priv, dev->dev_addr, vid,
+			       "vlan interface destroyed", false);
+
+	/* batadv_softif_vlan_get() increased the refcounter by 1 */
+	batadv_softif_vlan_free_ref(vlan);
+	/* finally free the vlan object */
+	batadv_softif_vlan_free_ref(vlan);
+
+	return 0;
+}
+
 /* batman-adv network devices have devices nesting below it and are a special
  * "super class" of normal network devices; split their locks off into a
  * separate class since they always nest.
@@ -585,6 +727,8 @@ static const struct net_device_ops batadv_netdev_ops = {
 	.ndo_open = batadv_interface_open,
 	.ndo_stop = batadv_interface_release,
 	.ndo_get_stats = batadv_interface_stats,
+	.ndo_vlan_rx_add_vid = batadv_interface_add_vid,
+	.ndo_vlan_rx_kill_vid = batadv_interface_kill_vid,
 	.ndo_set_mac_address = batadv_interface_set_mac_addr,
 	.ndo_change_mtu = batadv_interface_change_mtu,
 	.ndo_set_rx_mode = batadv_interface_set_rx_mode,
@@ -624,6 +768,7 @@ static void batadv_softif_init_early(struct net_device *dev)
 
 	dev->netdev_ops = &batadv_netdev_ops;
 	dev->destructor = batadv_softif_free;
+	dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
 	dev->tx_queue_len = 0;
 
 	/* can't call min_mtu, because the needed variables
diff --git a/soft-interface.h b/soft-interface.h
index 2f2472c..16d9be6 100644
--- a/soft-interface.h
+++ b/soft-interface.h
@@ -28,5 +28,6 @@ struct net_device *batadv_softif_create(const char *name);
 void batadv_softif_destroy_sysfs(struct net_device *soft_iface);
 int batadv_softif_is_valid(const struct net_device *net_dev);
 extern struct rtnl_link_ops batadv_link_ops;
+int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid);
 
 #endif /* _NET_BATMAN_ADV_SOFT_INTERFACE_H_ */
diff --git a/types.h b/types.h
index 20a1bef..9fdf2c2 100644
--- a/types.h
+++ b/types.h
@@ -530,6 +530,22 @@ struct batadv_priv_nc {
 	struct batadv_hashtable *decoding_hash;
 };
 
+/*
+ * struct batadv_softif_vlan - per VLAN attributes set
+ * @vid: VLAN identifier
+ * @kobj: kobject for sysfs vlan subdirectory
+ * @list: list node for bat_priv::softif_vlan_list
+ * @refcount: number of context where this object is currently in use
+ * @rcu: struct used for freeing in a RCU-safe manner
+ */
+struct batadv_softif_vlan {
+	unsigned short vid;
+	struct kobject *kobj;
+	struct list_head list;
+	atomic_t refcount;
+	struct rcu_head rcu;
+};
+
 /**
  * struct batadv_priv - per mesh interface data
  * @mesh_state: current status of the mesh (inactive/active/deactivating)
@@ -566,6 +582,9 @@ struct batadv_priv_nc {
  * @primary_if: one of the hard interfaces assigned to this mesh interface
  *  becomes the primary interface
  * @bat_algo_ops: routing algorithm used by this mesh interface
+ * @softif_vlan_list: a list of softif_vlan structs, one per VLAN created on top
+ *  of the mesh interface represented by this object
+ * @softif_vlan_list_lock: lock protecting softif_vlan_list
  * @bla: bridge loope avoidance data
  * @debug_log: holding debug logging relevant data
  * @gw: gateway data
@@ -613,6 +632,8 @@ struct batadv_priv {
 	struct work_struct cleanup_work;
 	struct batadv_hard_iface __rcu *primary_if;  /* rcu protected pointer */
 	struct batadv_algo_ops *bat_algo_ops;
+	struct list_head softif_vlan_list;
+	spinlock_t softif_vlan_list_lock; /* protects softif_vlan_list */
 #ifdef CONFIG_BATMAN_ADV_BLA
 	struct batadv_priv_bla bla;
 #endif
-- 
1.8.1.5

[B.A.T.M.A.N.] [PATCHv5 2/2] batman-adv: add sysfs framework for VLAN

[Antonio Quartulli]

From: Antonio Quartulli <antonio@open-mesh.com>

Each VLAN can now have its own set of attributes.
Export them through a new subfolder in the sysfs tree.
Each VLAN created on top of a soft_iface will have its own
subfolder.

The subfolder is named "vlan%VID" and it is created inside
the "mesh" sysfs folder belonging to batman-adv.

Since the fake-VLAN representing the standalone soft_iface
has no real vid, its subfolder is named "novlan".

Create all the needed macros and data structures to easily
handle new VLAN spacific attributes.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
---

v5:
- added description for "novlan" subfolder in the commit message
- "novlan" folder introduction has been correctly merged into this patch


 soft-interface.c |   7 +++
 sysfs.c          | 142 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 sysfs.h          |  10 ++++
 3 files changed, 159 insertions(+)

diff --git a/soft-interface.c b/soft-interface.c
index f7552c5..c866933 100644
--- a/soft-interface.c
+++ b/soft-interface.c
@@ -434,6 +434,7 @@ batadv_softif_vlan_get(struct batadv_priv *bat_priv, unsigned short vid)
 int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid)
 {
 	struct batadv_softif_vlan *vlan;
+	int err;
 
 	vlan = kzalloc(sizeof(*vlan), GFP_ATOMIC);
 	if (!vlan)
@@ -449,6 +450,10 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid)
 			    bat_priv->soft_iface->dev_addr, vid,
 			    BATADV_NULL_IFINDEX);
 
+	err = batadv_sysfs_add_vlan(bat_priv->soft_iface, vlan);
+	if (err)
+		return err;
+
 	spin_lock_bh(&bat_priv->softif_vlan_list_lock);
 	list_add_rcu(&vlan->list, &bat_priv->softif_vlan_list);
 	spin_unlock_bh(&bat_priv->softif_vlan_list_lock);
@@ -512,6 +517,8 @@ static int batadv_interface_kill_vid(struct net_device *dev, __be16 proto,
 	list_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
 	 */
diff --git a/sysfs.c b/sysfs.c
index b70ae52..32bdc46 100644
--- a/sysfs.c
+++ b/sysfs.c
@@ -39,6 +39,31 @@ static struct batadv_priv *batadv_kobj_to_batpriv(struct kobject *obj)
 	return netdev_priv(net_dev);
 }
 
+/**
+ * batadv_kobj_to_vlan - convert a kobj in the associated softif_vlan struct
+ * @obj: kobject to covert
+ *
+ * Return the associated softif_vlan struct if cound, NULL otherwise
+ */
+static struct batadv_softif_vlan *batadv_kobj_to_vlan(struct kobject *obj)
+{
+	struct batadv_priv *bat_priv = batadv_kobj_to_batpriv(obj->parent);
+	struct batadv_softif_vlan *vlan, *vlan_tmp = NULL;
+
+	list_for_each_entry_rcu(vlan, &bat_priv->softif_vlan_list, list) {
+		if (vlan->kobj != obj)
+			continue;
+
+		if (!atomic_inc_not_zero(&vlan->refcount))
+			continue;
+
+		vlan_tmp = vlan;
+		break;
+	}
+
+	return vlan_tmp;
+}
+
 #define BATADV_UEV_TYPE_VAR	"BATTYPE="
 #define BATADV_UEV_ACTION_VAR	"BATACTION="
 #define BATADV_UEV_DATA_VAR	"BATDATA="
@@ -53,6 +78,15 @@ static char *batadv_uev_type_str[] = {
 	"gw"
 };
 
+/* Use this, if you have customized show and store functions for vlan attrs */
+#define BATADV_ATTR_VLAN(_name, _mode, _show, _store)	\
+struct batadv_attribute batadv_attr_vlan_##_name = {	\
+	.attr = {.name = __stringify(_name),		\
+		 .mode = _mode },			\
+	.show   = _show,				\
+	.store  = _store,				\
+};
+
 /* Use this, if you have customized show and store functions */
 #define BATADV_ATTR(_name, _mode, _show, _store)	\
 struct batadv_attribute batadv_attr_##_name = {		\
@@ -122,6 +156,38 @@ ssize_t batadv_show_##_name(struct kobject *kobj,			\
 	static BATADV_ATTR(_name, _mode, batadv_show_##_name,		\
 			   batadv_store_##_name)
 
+#define BATADV_ATTR_VLAN_STORE_BOOL(_name, _post_func)			\
+ssize_t batadv_store_vlan_##_name(struct kobject *kobj,			\
+				  struct attribute *attr, char *buff,	\
+				  size_t count)				\
+{									\
+	struct batadv_priv *bat_priv = batadv_kobj_to_batpriv(kobj->parent);\
+	struct batadv_softif_vlan *vlan = batadv_kobj_to_vlan(kobj);	\
+	size_t res = __batadv_store_bool_attr(buff, count, _post_func, attr,\
+					      &vlan->_name,		\
+					      bat_priv->soft_iface);	\
+	batadv_softif_vlan_free_ref(vlan);				\
+	return res;							\
+}
+
+#define BATADV_ATTR_VLAN_SHOW_BOOL(_name)				\
+ssize_t batadv_show_vlan_##_name(struct kobject *kobj,			\
+			    struct attribute *attr, char *buff)		\
+{									\
+	struct batadv_softif_vlan *vlan = batadv_kobj_to_vlan(kobj);	\
+	size_t res =  sprintf(buff, "%s\n",				\
+			      atomic_read(&vlan->_name) == 0 ?		\
+			      "disabled" : "enabled");			\
+	batadv_softif_vlan_free_ref(vlan);				\
+	return res;							\
+}
+
+/* Use this, if you are going to turn a [name] in the vlan struct on or off */
+#define BATADV_ATTR_VLAN_BOOL(_name, _mode, _post_func)			\
+	static BATADV_ATTR_VLAN_STORE_BOOL(_name, _post_func)		\
+	static BATADV_ATTR_VLAN_SHOW_BOOL(_name)			\
+	static BATADV_ATTR_VLAN(_name, _mode, batadv_show_vlan_##_name,	\
+				batadv_store_vlan_##_name)
 
 static int batadv_store_bool_attr(char *buff, size_t count,
 				  struct net_device *net_dev,
@@ -403,6 +469,13 @@ static struct batadv_attribute *batadv_mesh_attrs[] = {
 	NULL,
 };
 
+/**
+ * batadv_vlan_attrs - array of vlan specific sysfs attributes
+ */
+static struct batadv_attribute *batadv_vlan_attrs[] = {
+	NULL,
+};
+
 int batadv_sysfs_add_meshif(struct net_device *dev)
 {
 	struct kobject *batif_kobject = &dev->dev.kobj;
@@ -453,6 +526,75 @@ void batadv_sysfs_del_meshif(struct net_device *dev)
 	bat_priv->mesh_obj = NULL;
 }
 
+/**
+ * batadv_sysfs_add_vlan - add all the needed sysfs objects for the new vlan
+ * @dev: netdev of the mesh interface
+ * @vlan: private data of the newly added VLAN interface
+ *
+ * Return 0 on success and -ENOMEM if any of the structure allocations fails
+ */
+int batadv_sysfs_add_vlan(struct net_device *dev,
+			  struct batadv_softif_vlan *vlan)
+{
+	struct batadv_priv *bat_priv = netdev_priv(dev);
+	struct batadv_attribute **bat_attr;
+	char vlan_subdir_str[256], *vlan_subdir;
+	int err;
+
+	vlan_subdir = "novlan";
+	if (vlan->vid & BATADV_VLAN_HAS_TAG) {
+		sprintf(vlan_subdir_str, BATADV_SYSFS_VLAN_SUBDIR_PREFIX "%u",
+			vlan->vid & VLAN_VID_MASK);
+		vlan_subdir = vlan_subdir_str;
+	}
+
+	vlan->kobj = kobject_create_and_add(vlan_subdir, bat_priv->mesh_obj);
+	if (!vlan->kobj) {
+		batadv_err(dev, "Can't add sysfs directory: %s/%s\n", dev->name,
+			   vlan_subdir);
+		goto out;
+	}
+
+	for (bat_attr = batadv_vlan_attrs; *bat_attr; ++bat_attr) {
+		err = sysfs_create_file(vlan->kobj,
+					&((*bat_attr)->attr));
+		if (err) {
+			batadv_err(dev, "Can't add sysfs file: %s/%s/%s\n",
+				   dev->name, vlan_subdir,
+				   ((*bat_attr)->attr).name);
+			goto rem_attr;
+		}
+	}
+
+	return 0;
+
+rem_attr:
+	for (bat_attr = batadv_vlan_attrs; *bat_attr; ++bat_attr)
+		sysfs_remove_file(vlan->kobj, &((*bat_attr)->attr));
+
+	kobject_put(vlan->kobj);
+	vlan->kobj = NULL;
+out:
+	return -ENOMEM;
+}
+
+/**
+ * batadv_sysfs_del_vlan - remove all the sysfs objects for a given VLAN
+ * @bat_priv: the bat priv with all the soft interface information
+ * @vlan: the private data of the VLAN to destroy
+ */
+void batadv_sysfs_del_vlan(struct batadv_priv *bat_priv,
+			   struct batadv_softif_vlan *vlan)
+{
+	struct batadv_attribute **bat_attr;
+
+	for (bat_attr = batadv_vlan_attrs; *bat_attr; ++bat_attr)
+		sysfs_remove_file(vlan->kobj, &((*bat_attr)->attr));
+
+	kobject_put(vlan->kobj);
+	vlan->kobj = NULL;
+}
+
 static ssize_t batadv_show_mesh_iface(struct kobject *kobj,
 				      struct attribute *attr, char *buff)
 {
diff --git a/sysfs.h b/sysfs.h
index 479acf4..c4f96c1 100644
--- a/sysfs.h
+++ b/sysfs.h
@@ -22,6 +22,12 @@
 
 #define BATADV_SYSFS_IF_MESH_SUBDIR "mesh"
 #define BATADV_SYSFS_IF_BAT_SUBDIR "batman_adv"
+/**
+ * BATADV_SYSFS_VLAN_SUBDIR_PREFIX - prefix of the subfolder that will be
+ *  created in the sysfs hierarchy for each VLAN interface. The subfolder will
+ *  be named "BATADV_SYSFS_VLAN_SUBDIR_PREFIX%vid"
+ */
+#define BATADV_SYSFS_VLAN_SUBDIR_PREFIX "vlan"
 
 struct batadv_attribute {
 	struct attribute attr;
@@ -36,6 +42,10 @@ void batadv_sysfs_del_meshif(struct net_device *dev);
 int batadv_sysfs_add_hardif(struct kobject **hardif_obj,
 			    struct net_device *dev);
 void batadv_sysfs_del_hardif(struct kobject **hardif_obj);
+int batadv_sysfs_add_vlan(struct net_device *dev,
+			  struct batadv_softif_vlan *vlan);
+void batadv_sysfs_del_vlan(struct batadv_priv *bat_priv,
+			   struct batadv_softif_vlan *vlan);
 int batadv_throw_uevent(struct batadv_priv *bat_priv, enum batadv_uev_type type,
 			enum batadv_uev_action action, const char *data);
 
-- 
1.8.1.5