batman-adv: Allow to use rntl_link for device creation/deletion

The sysfs configuration interface of batman-adv to add/remove soft-interfaces
is not deadlock free and doesn't follow the currently common way to create new
virtual interfaces.

An additional interface though rtnl_link is introduced which provides easy device
creation/deletion with tools like "ip":

$ ip link add dev bat0 type batadv
$ ip link del dev bat0

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

4 files changed, 33 insertions, 0 deletions

diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 0495a7dc7505..62b1f89b7b4d 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -71,6 +71,7 @@ static int __init batadv_init(void)
         batadv_debugfs_init();
 
         register_netdevice_notifier(&batadv_hard_if_notifier);
+        rtnl_link_register(&batadv_link_ops);
 
         pr_info("B.A.T.M.A.N. advanced %s (compatibility version %i) loaded\n",
                 BATADV_SOURCE_VERSION, BATADV_COMPAT_VERSION);
@@ -81,6 +82,7 @@ static int __init batadv_init(void)
 static void __exit batadv_exit(void)
 {
         batadv_debugfs_destroy();
+        rtnl_link_unregister(&batadv_link_ops);
         unregister_netdevice_notifier(&batadv_hard_if_notifier);
         batadv_hardif_remove_interfaces();
 
diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h
index 0afd4ee7708b..a9e12e65aa15 100644
--- a/net/batman-adv/main.h
+++ b/net/batman-adv/main.h
@@ -152,6 +152,7 @@ enum batadv_uev_type {
 #include <linux/percpu.h>
 #include <linux/slab.h>
 #include <net/sock.h>           /* struct sock */
+#include <net/rtnetlink.h>
 #include <linux/jiffies.h>
 #include <linux/seq_file.h>
 #include "types.h"
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index bc77a5be960d..545c863b35fc 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -570,6 +570,8 @@ struct net_device *batadv_softif_create(const char *name)
         if (!soft_iface)
                 return NULL;
 
+        soft_iface->rtnl_link_ops = &batadv_link_ops;
+
         ret = register_netdevice(soft_iface);
         if (ret < 0) {
                 pr_err("Unable to register the batman interface '%s': %i\n",
@@ -592,6 +594,26 @@ void batadv_softif_destroy_sysfs(struct net_device *soft_iface)
         queue_work(batadv_event_workqueue, &bat_priv->cleanup_work);
 }
 
+/**
+ * batadv_softif_destroy_netlink - deletion of batadv_soft_interface via netlink
+ * @soft_iface: the to-be-removed batman-adv interface
+ * @head: list pointer
+ */
+static void batadv_softif_destroy_netlink(struct net_device *soft_iface,
+                                          struct list_head *head)
+{
+        struct batadv_hard_iface *hard_iface;
+
+        list_for_each_entry(hard_iface, &batadv_hardif_list, list) {
+                if (hard_iface->soft_iface == soft_iface)
+                        batadv_hardif_disable_interface(hard_iface,
+                                                        BATADV_IF_CLEANUP_KEEP);
+        }
+
+        batadv_sysfs_del_meshif(soft_iface);
+        unregister_netdevice_queue(soft_iface, head);
+}
+
 int batadv_softif_is_valid(const struct net_device *net_dev)
 {
         if (net_dev->netdev_ops->ndo_start_xmit == batadv_interface_tx)
@@ -600,6 +622,13 @@ int batadv_softif_is_valid(const struct net_device *net_dev)
         return 0;
 }
 
+struct rtnl_link_ops batadv_link_ops __read_mostly = {
+        .kind           = "batadv",
+        .priv_size      = sizeof(struct batadv_priv),
+        .setup          = batadv_softif_init_early,
+        .dellink        = batadv_softif_destroy_netlink,
+};
+
 /* ethtool */
 static int batadv_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
 {
diff --git a/net/batman-adv/soft-interface.h b/net/batman-adv/soft-interface.h
index 49bc66bb774a..2f2472c2ea0d 100644
--- a/net/batman-adv/soft-interface.h
+++ b/net/batman-adv/soft-interface.h
@@ -27,5 +27,6 @@ void batadv_interface_rx(struct net_device *soft_iface,
 struct net_device *batadv_softif_create(const char *name);
 void batadv_softif_destroy_sysfs(struct net_device *soft_iface);
 int batadv_softif_is_valid(const struct net_device *net_dev);
+extern struct rtnl_link_ops batadv_link_ops;
 
 #endif /* _NET_BATMAN_ADV_SOFT_INTERFACE_H_ */