ieee802154: fix netns settings

6LoWPAN currently doesn't supports x-netns and works only in init_net.

With this patch, we ensure that:
 - the wpan interface cannot be moved to another netns;
 - the 6lowpan interface cannot be moved to another netns;
 - the wpan interface is in the same netns than the 6lowpan interface;
 - the 6lowpan interface is in init_net.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: NAlexander Aring <alex.aring@gmail.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

net/ieee802154/6lowpan/core.c

@@ -126,6 +126,7 @@ static void lowpan_setup(struct net_device *dev)
 	dev->header_ops		= &lowpan_header_ops;
 	dev->ml_priv		= &lowpan_mlme;
 	dev->destructor		= free_netdev;
+	dev->features		|= NETIF_F_NETNS_LOCAL;
 }
 
 static int lowpan_validate(struct nlattr *tb[], struct nlattr *data[])
@@ -148,10 +149,11 @@ static int lowpan_newlink(struct net *src_net, struct net_device *dev,
 
 	pr_debug("adding new link\n");
 
-	if (!tb[IFLA_LINK])
+	if (!tb[IFLA_LINK] ||
+	    !net_eq(dev_net(dev), &init_net))
 		return -EINVAL;
 	/* find and hold real wpan device */
-	real_dev = dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
+	real_dev = dev_get_by_index(dev_net(dev), nla_get_u32(tb[IFLA_LINK]));
 	if (!real_dev)
 		return -ENODEV;
 	if (real_dev->type != ARPHRD_IEEE802154) {

net/ieee802154/core.c

@@ -225,6 +225,7 @@ static int cfg802154_netdev_notifier_call(struct notifier_block *nb,
 	switch (state) {
 		/* TODO NETDEV_DEVTYPE */
 	case NETDEV_REGISTER:
+		dev->features |= NETIF_F_NETNS_LOCAL;
 		wpan_dev->identifier = ++rdev->wpan_dev_id;
 		list_add_rcu(&wpan_dev->list, &rdev->wpan_dev_list);
 		rdev->devlist_generation++;