batman-adv: Add the backbone gateway list to debugfs

This is especially useful if there are no claims yet, but we still want
to know which gateways are using bridge loop avoidance in the network.
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

Documentation/networking/batman-adv.txt

@@ -76,8 +76,9 @@ folder:
 There is a special folder for debugging information:
 
 # ls /sys/kernel/debug/batman_adv/bat0/
-# bla_claim_table    log                socket             transtable_local
-# gateways           originators        transtable_global  vis_data
+# bla_backbone_table  log                 transtable_global
+# bla_claim_table     originators         transtable_local
+# gateways            socket              vis_data
 
 Some of the files contain all sort of status information  regard-
 ing  the  mesh  network.  For  example, you can view the table of

net/batman-adv/bridge_loop_avoidance.c

@@ -1616,3 +1616,68 @@ int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
 		batadv_hardif_free_ref(primary_if);
 	return ret;
 }
+
+int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset)
+{
+	struct net_device *net_dev = (struct net_device *)seq->private;
+	struct batadv_priv *bat_priv = netdev_priv(net_dev);
+	struct batadv_hashtable *hash = bat_priv->backbone_hash;
+	struct batadv_backbone_gw *backbone_gw;
+	struct batadv_hard_iface *primary_if;
+	struct hlist_node *node;
+	struct hlist_head *head;
+	int secs, msecs;
+	uint32_t i;
+	bool is_own;
+	int ret = 0;
+	uint8_t *primary_addr;
+
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+	if (!primary_if) {
+		ret = seq_printf(seq,
+				 "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
+				 net_dev->name);
+		goto out;
+	}
+
+	if (primary_if->if_status != BATADV_IF_ACTIVE) {
+		ret = seq_printf(seq,
+				 "BATMAN mesh %s disabled - primary interface not active\n",
+				 net_dev->name);
+		goto out;
+	}
+
+	primary_addr = primary_if->net_dev->dev_addr;
+	seq_printf(seq,
+		   "Backbones announced for the mesh %s (orig %pM, group id %04x)\n",
+		   net_dev->name, primary_addr,
+		   ntohs(bat_priv->claim_dest.group));
+	seq_printf(seq, "   %-17s    %-5s %-9s (%-4s)\n",
+		   "Originator", "VID", "last seen", "CRC");
+	for (i = 0; i < hash->size; i++) {
+		head = &hash->table[i];
+
+		rcu_read_lock();
+		hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
+			msecs = jiffies_to_msecs(jiffies -
+						 backbone_gw->lasttime);
+			secs = msecs / 1000;
+			msecs = msecs % 1000;
+
+			is_own = batadv_compare_eth(backbone_gw->orig,
+						    primary_addr);
+			if (is_own)
+				continue;
+
+			seq_printf(seq,
+				   " * %pM on % 5d % 4i.%03is (%04x)\n",
+				   backbone_gw->orig, backbone_gw->vid,
+				   secs, msecs, backbone_gw->crc);
+		}
+		rcu_read_unlock();
+	}
+out:
+	if (primary_if)
+		batadv_hardif_free_ref(primary_if);
+	return ret;
+}

net/batman-adv/bridge_loop_avoidance.h

@@ -27,6 +27,8 @@ int batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb, short vid);
 int batadv_bla_is_backbone_gw(struct sk_buff *skb,
 			      struct batadv_orig_node *orig_node, int hdr_size);
 int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset);
+int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq,
+					     void *offset);
 int batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, uint8_t *orig);
 int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
 				   struct batadv_bcast_packet *bcast_packet,
@@ -65,6 +67,12 @@ static inline int batadv_bla_claim_table_seq_print_text(struct seq_file *seq,
 	return 0;
 }
 
+static inline int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq,
+							   void *offset)
+{
+	return 0;
+}
+
 static inline int batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv,
 						 uint8_t *orig)
 {

net/batman-adv/debugfs.c

@@ -267,6 +267,15 @@ static int batadv_bla_claim_table_open(struct inode *inode, struct file *file)
 	return single_open(file, batadv_bla_claim_table_seq_print_text,
 			   net_dev);
 }
+
+static int batadv_bla_backbone_table_open(struct inode *inode,
+					  struct file *file)
+{
+	struct net_device *net_dev = (struct net_device *)inode->i_private;
+	return single_open(file, batadv_bla_backbone_table_seq_print_text,
+			   net_dev);
+}
+
 #endif
 
 static int batadv_transtable_local_open(struct inode *inode, struct file *file)
@@ -305,6 +314,8 @@ static BATADV_DEBUGINFO(transtable_global, S_IRUGO,
 			batadv_transtable_global_open);
 #ifdef CONFIG_BATMAN_ADV_BLA
 static BATADV_DEBUGINFO(bla_claim_table, S_IRUGO, batadv_bla_claim_table_open);
+static BATADV_DEBUGINFO(bla_backbone_table, S_IRUGO,
+			batadv_bla_backbone_table_open);
 #endif
 static BATADV_DEBUGINFO(transtable_local, S_IRUGO,
 			batadv_transtable_local_open);
@@ -316,6 +327,7 @@ static struct batadv_debuginfo *batadv_mesh_debuginfos[] = {
 	&batadv_debuginfo_transtable_global,
 #ifdef CONFIG_BATMAN_ADV_BLA
 	&batadv_debuginfo_bla_claim_table,
+	&batadv_debuginfo_bla_backbone_table,
 #endif
 	&batadv_debuginfo_transtable_local,
 	&batadv_debuginfo_vis_data,