batman-adv: add per VLAN interface attribute framework

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>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>

1 files changed, 171 insertions, 0 deletions

diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 279e91d570a7..936b83bb02de 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -393,6 +393,166 @@ 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
+ *
+ * Returns 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_tmp, *vlan = NULL;
+
+        rcu_read_lock();
+        hlist_for_each_entry_rcu(vlan_tmp, &bat_priv->softif_vlan_list, list) {
+                if (vlan_tmp->vid != vid)
+                        continue;
+
+                if (!atomic_inc_not_zero(&vlan_tmp->refcount))
+                        continue;
+
+                vlan = vlan_tmp;
+                break;
+        }
+        rcu_read_unlock();
+
+        return vlan;
+}
+
+/**
+ * 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
+ *
+ * Returns 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 = batadv_softif_vlan_get(bat_priv, vid);
+        if (vlan) {
+                batadv_softif_vlan_free_ref(vlan);
+                return -EEXIST;
+        }
+
+        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);
+        hlist_add_head_rcu(&vlan->list, &bat_priv->softif_vlan_list);
+        spin_unlock_bh(&bat_priv->softif_vlan_list_lock);
+
+        return 0;
+}
+
+/**
+ * batadv_softif_destroy_vlan - remove and destroy a softif_vlan object
+ * @bat_priv: the bat priv with all the soft interface information
+ * @vlan: the object to remove
+ */
+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);
+
+        /* 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_softif_vlan_free_ref(vlan);
+}
+
+/**
+ * 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
+ *
+ * Returns 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
+ *
+ * Returns 0 on success, -EINVAL if the specified prototype is not ETH_P_8021Q
+ * or -ENOENT if the specified vlan id wasn't registered.
+ */
+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;
+
+        batadv_softif_destroy_vlan(bat_priv, 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.
@@ -432,6 +592,7 @@ static void batadv_set_lockdep_class(struct net_device *dev)
  */
 static void batadv_softif_destroy_finish(struct work_struct *work)
 {
+        struct batadv_softif_vlan *vlan;
         struct batadv_priv *bat_priv;
         struct net_device *soft_iface;
 
@@ -439,6 +600,13 @@ static void batadv_softif_destroy_finish(struct work_struct *work)
                                 cleanup_work);
         soft_iface = bat_priv->soft_iface;
 
+        /* destroy the "untagged" VLAN */
+        vlan = batadv_softif_vlan_get(bat_priv, BATADV_NO_FLAGS);
+        if (vlan) {
+                batadv_softif_destroy_vlan(bat_priv, vlan);
+                batadv_softif_vlan_free_ref(vlan);
+        }
+
         batadv_sysfs_del_meshif(soft_iface);
 
         rtnl_lock();
@@ -594,6 +762,8 @@ 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,
@@ -633,6 +803,7 @@ 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