batman-adv: add B.A.T.M.A.N. IV bat_gw_dump implementations

Dump the list of gateways via the netlink socket.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
[sven.eckelmann@open-mesh.com: integrate in batadv_algo_ops]
Signed-off-by: Sven Eckelmann <sven.eckelmann@open-mesh.com>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>

net/batman-adv/bat_iv_ogm.c

@@ -2681,6 +2681,110 @@ static void batadv_iv_gw_print(struct batadv_priv *bat_priv,
 		seq_puts(seq, "No gateways in range ...\n");
 }
 
+/**
+ * batadv_iv_gw_dump_entry - Dump a gateway into a message
+ * @msg: Netlink message to dump into
+ * @portid: Port making netlink request
+ * @seq: Sequence number of netlink message
+ * @bat_priv: The bat priv with all the soft interface information
+ * @gw_node: Gateway to be dumped
+ *
+ * Return: Error code, or 0 on success
+ */
+static int batadv_iv_gw_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
+				   struct batadv_priv *bat_priv,
+				   struct batadv_gw_node *gw_node)
+{
+	struct batadv_neigh_ifinfo *router_ifinfo = NULL;
+	struct batadv_neigh_node *router;
+	struct batadv_gw_node *curr_gw;
+	int ret = -EINVAL;
+	void *hdr;
+
+	router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT);
+	if (!router)
+		goto out;
+
+	router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
+	if (!router_ifinfo)
+		goto out;
+
+	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
+
+	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family,
+			  NLM_F_MULTI, BATADV_CMD_GET_GATEWAYS);
+	if (!hdr) {
+		ret = -ENOBUFS;
+		goto out;
+	}
+
+	ret = -EMSGSIZE;
+
+	if (curr_gw == gw_node)
+		if (nla_put_flag(msg, BATADV_ATTR_FLAG_BEST)) {
+			genlmsg_cancel(msg, hdr);
+			goto out;
+		}
+
+	if (nla_put(msg, BATADV_ATTR_ORIG_ADDRESS, ETH_ALEN,
+		    gw_node->orig_node->orig) ||
+	    nla_put_u8(msg, BATADV_ATTR_TQ, router_ifinfo->bat_iv.tq_avg) ||
+	    nla_put(msg, BATADV_ATTR_ROUTER, ETH_ALEN,
+		    router->addr) ||
+	    nla_put_string(msg, BATADV_ATTR_HARD_IFNAME,
+			   router->if_incoming->net_dev->name) ||
+	    nla_put_u32(msg, BATADV_ATTR_BANDWIDTH_DOWN,
+			gw_node->bandwidth_down) ||
+	    nla_put_u32(msg, BATADV_ATTR_BANDWIDTH_UP,
+			gw_node->bandwidth_up)) {
+		genlmsg_cancel(msg, hdr);
+		goto out;
+	}
+
+	genlmsg_end(msg, hdr);
+	ret = 0;
+
+out:
+	if (router_ifinfo)
+		batadv_neigh_ifinfo_put(router_ifinfo);
+	if (router)
+		batadv_neigh_node_put(router);
+	return ret;
+}
+
+/**
+ * batadv_iv_gw_dump - Dump gateways into a message
+ * @msg: Netlink message to dump into
+ * @cb: Control block containing additional options
+ * @bat_priv: The bat priv with all the soft interface information
+ */
+static void batadv_iv_gw_dump(struct sk_buff *msg, struct netlink_callback *cb,
+			      struct batadv_priv *bat_priv)
+{
+	int portid = NETLINK_CB(cb->skb).portid;
+	struct batadv_gw_node *gw_node;
+	int idx_skip = cb->args[0];
+	int idx = 0;
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
+		if (idx++ < idx_skip)
+			continue;
+
+		if (batadv_iv_gw_dump_entry(msg, portid, cb->nlh->nlmsg_seq,
+					    bat_priv, gw_node)) {
+			idx_skip = idx - 1;
+			goto unlock;
+		}
+	}
+
+	idx_skip = idx;
+unlock:
+	rcu_read_unlock();
+
+	cb->args[0] = idx_skip;
+}
+
 static struct batadv_algo_ops batadv_batman_iv __read_mostly = {
 	.name = "BATMAN_IV",
 	.iface = {
@@ -2707,6 +2811,7 @@ static struct batadv_algo_ops batadv_batman_iv __read_mostly = {
 		.get_best_gw_node = batadv_iv_gw_get_best_gw_node,
 		.is_eligible = batadv_iv_gw_is_eligible,
 		.print = batadv_iv_gw_print,
+		.dump = batadv_iv_gw_dump,
 	},
 };