[PATCH 7/7] batman-adv: Allow to modify slaves of soft-interfaces through rntl_link

[Sven Eckelmann <sven@narfation.org>]

The sysfs configuration interface of batman-adv to add/remove slaves of an
soft-iface is not deadlock free and doesn't follow the currently common way to
modify slaves of an interface.

An additional configuration interface though rtnl_link is introduced which
provides easy device adding/removing with tools like "ip":
$ ip link set dev eth0 master bat0
$ ip link set dev eth0 nomaster

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 net/batman-adv/soft-interface.c |   39 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index fcb510e..8d4ee5c 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -476,6 +476,41 @@ free_bat_counters:
 	return ret;
 }
 
+/**
+ * batadv_add_slave - Add a slave interface to a batadv_soft_interface
+ * @dev: batadv_soft_interface used as master interface
+ * @slave_dev: net_device which should become the slave interface
+ */
+static int batadv_add_slave(struct net_device *dev,
+			    struct net_device *slave_dev)
+{
+	struct batadv_hard_iface *hard_iface;
+
+	hard_iface = batadv_hardif_get_by_netdev(slave_dev);
+	if (!hard_iface || hard_iface->soft_iface != NULL)
+		return -EINVAL;
+
+	return batadv_hardif_enable_interface(hard_iface, dev->name);
+}
+
+/**
+ * batadv_del_slave - Delete a slave interface from a batadv_soft_interface
+ * @dev: batadv_soft_interface used as master interface
+ * @slave_dev: net_device which should be removed from the master interface
+ */
+static int batadv_del_slave(struct net_device *dev,
+			    struct net_device *slave_dev)
+{
+	struct batadv_hard_iface *hard_iface;
+
+	hard_iface = batadv_hardif_get_by_netdev(slave_dev);
+	if (!hard_iface || hard_iface->soft_iface != dev)
+		return -EINVAL;
+
+	batadv_hardif_disable_interface(hard_iface, BATADV_IF_CLEANUP_KEEP);
+	return 0;
+}
+
 static const struct net_device_ops batadv_netdev_ops = {
 	.ndo_init = batadv_softif_init,
 	.ndo_open = batadv_interface_open,
@@ -484,7 +519,9 @@ static const struct net_device_ops batadv_netdev_ops = {
 	.ndo_set_mac_address = batadv_interface_set_mac_addr,
 	.ndo_change_mtu = batadv_interface_change_mtu,
 	.ndo_start_xmit = batadv_interface_tx,
-	.ndo_validate_addr = eth_validate_addr
+	.ndo_validate_addr = eth_validate_addr,
+	.ndo_add_slave = batadv_add_slave,
+	.ndo_del_slave = batadv_del_slave,
 };
 
 /**
-- 
1.7.10.4