batman-adv: implement AP-isolation on the receiver side

When a node receives a unicast packet it checks if the source and the
destination client can communicate or not due to the AP isolation
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>

Documentation/ABI/testing/sysfs-class-net-mesh

@@ -22,6 +22,14 @@ Description:
                 mesh will be fragmented or silently discarded if the
                 packet size exceeds the outgoing interface MTU.
 
+What:		/sys/class/net/<mesh_iface>/mesh/ap_isolation
+Date:		May 2011
+Contact:	Antonio Quartulli <ordex@autistici.org>
+Description:
+		Indicates whether the data traffic going from a
+		wireless client to another wireless client will be
+		silently dropped.
+
 What:           /sys/class/net/<mesh_iface>/mesh/gw_bandwidth
 Date:           October 2010
 Contact:        Marek Lindner <lindner_marek@yahoo.de>

net/batman-adv/bat_sysfs.c

@@ -380,6 +380,7 @@ static ssize_t store_gw_bwidth(struct kobject *kobj, struct attribute *attr,
 BAT_ATTR_BOOL(aggregated_ogms, S_IRUGO | S_IWUSR, NULL);
 BAT_ATTR_BOOL(bonding, S_IRUGO | S_IWUSR, NULL);
 BAT_ATTR_BOOL(fragmentation, S_IRUGO | S_IWUSR, update_min_mtu);
+BAT_ATTR_BOOL(ap_isolation, S_IRUGO | S_IWUSR, NULL);
 static BAT_ATTR(vis_mode, S_IRUGO | S_IWUSR, show_vis_mode, store_vis_mode);
 static BAT_ATTR(gw_mode, S_IRUGO | S_IWUSR, show_gw_mode, store_gw_mode);
 BAT_ATTR_UINT(orig_interval, S_IRUGO | S_IWUSR, 2 * JITTER, INT_MAX, NULL);
@@ -396,6 +397,7 @@ static struct bat_attribute *mesh_attrs[] = {
 	&bat_attr_aggregated_ogms,
 	&bat_attr_bonding,
 	&bat_attr_fragmentation,
+	&bat_attr_ap_isolation,
 	&bat_attr_vis_mode,
 	&bat_attr_gw_mode,
 	&bat_attr_orig_interval,

net/batman-adv/soft-interface.c

@@ -739,6 +739,9 @@ void interface_rx(struct net_device *soft_iface,
 
 	soft_iface->last_rx = jiffies;
 
+	if (is_ap_isolated(bat_priv, ethhdr->h_source, ethhdr->h_dest))
+		goto dropped;
+
 	netif_rx(skb);
 	goto out;
 
@@ -812,6 +815,7 @@ struct net_device *softif_create(const char *name)
 
 	atomic_set(&bat_priv->aggregated_ogms, 1);
 	atomic_set(&bat_priv->bonding, 0);
+	atomic_set(&bat_priv->ap_isolation, 0);
 	atomic_set(&bat_priv->vis_mode, VIS_TYPE_CLIENT_UPDATE);
 	atomic_set(&bat_priv->gw_mode, GW_MODE_OFF);
 	atomic_set(&bat_priv->gw_sel_class, 20);

net/batman-adv/translation-table.c

@@ -781,6 +781,18 @@ static void tt_global_table_free(struct bat_priv *bat_priv)
 	bat_priv->tt_global_hash = NULL;
 }
 
+static bool _is_ap_isolated(struct tt_local_entry *tt_local_entry,
+			    struct tt_global_entry *tt_global_entry)
+{
+	bool ret = false;
+
+	if (tt_local_entry->flags & TT_CLIENT_WIFI &&
+	    tt_global_entry->flags & TT_CLIENT_WIFI)
+		ret = true;
+
+	return ret;
+}
+
 struct orig_node *transtable_search(struct bat_priv *bat_priv,
 				    const uint8_t *addr)
 {
@@ -1729,3 +1741,33 @@ void tt_commit_changes(struct bat_priv *bat_priv)
 	atomic_inc(&bat_priv->ttvn);
 	bat_priv->tt_poss_change = false;
 }
+
+bool is_ap_isolated(struct bat_priv *bat_priv, uint8_t *src, uint8_t *dst)
+{
+	struct tt_local_entry *tt_local_entry = NULL;
+	struct tt_global_entry *tt_global_entry = NULL;
+	bool ret = true;
+
+	if (!atomic_read(&bat_priv->ap_isolation))
+		return false;
+
+	tt_local_entry = tt_local_hash_find(bat_priv, dst);
+	if (!tt_local_entry)
+		goto out;
+
+	tt_global_entry = tt_global_hash_find(bat_priv, src);
+	if (!tt_global_entry)
+		goto out;
+
+	if (_is_ap_isolated(tt_local_entry, tt_global_entry))
+		goto out;
+
+	ret = false;
+
+out:
+	if (tt_global_entry)
+		tt_global_entry_free_ref(tt_global_entry);
+	if (tt_local_entry)
+		tt_local_entry_free_ref(tt_local_entry);
+	return ret;
+}

net/batman-adv/translation-table.h

@@ -63,5 +63,6 @@ void handle_tt_response(struct bat_priv *bat_priv,
 void send_roam_adv(struct bat_priv *bat_priv, uint8_t *client,
 		   struct orig_node *orig_node);
 void tt_commit_changes(struct bat_priv *bat_priv);
+bool is_ap_isolated(struct bat_priv *bat_priv, uint8_t *src, uint8_t *dst);
 
 #endif /* _NET_BATMAN_ADV_TRANSLATION_TABLE_H_ */

net/batman-adv/types.h

@@ -146,6 +146,7 @@ struct bat_priv {
 	atomic_t aggregated_ogms;	/* boolean */
 	atomic_t bonding;		/* boolean */
 	atomic_t fragmentation;		/* boolean */
+	atomic_t ap_isolation;		/* boolean */
 	atomic_t vis_mode;		/* VIS_TYPE_* */
 	atomic_t gw_mode;		/* GW_MODE_* */
 	atomic_t gw_sel_class;		/* uint */