[RFC net-next] veth: report NEWLINK event when moving the peer device in a new namespace
From: Lorenzo Bianconi <hidden>
Date: 2018-08-29 14:05:37
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
When moving a veth device to another namespace, userspace receives a RTM_DELLINK message indicating the device has been removed from current netns. However, the other peer does not receive a netlink event containing new values for IFLA_LINK_NETNSID and IFLA_LINK veth attributes. Fix that behaviour sending to userspace a RTM_NEWLINK message in the peer namespace to report new IFLA_LINK_NETNSID/IFLA_LINK values Reviewed-by: Stefano Brivio <redacted> Signed-off-by: Lorenzo Bianconi <redacted> --- drivers/net/veth.c | 60 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 59 insertions(+), 1 deletion(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 8d679c8b7f25..b27d46d8084a 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c@@ -1242,18 +1242,76 @@ static struct rtnl_link_ops veth_link_ops = { .get_link_net = veth_get_link_net, }; +static int veth_notify(struct notifier_block *this, + unsigned long event, void *ptr) +{ + struct net_device *peer, *dev = netdev_notifier_info_to_dev(ptr); + struct net *peer_net, *net = dev_net(dev); + int nsid, ret = NOTIFY_DONE; + struct veth_priv *priv; + + if (dev->netdev_ops != &veth_netdev_ops) + return NOTIFY_DONE; + + if (event != NETDEV_REGISTER) + return NOTIFY_DONE; + + priv = netdev_priv(dev); + + rcu_read_lock(); + + peer = rcu_dereference(priv->peer); + if (!peer) + goto out; + + peer_net = dev_net(peer); + /* do not forward events if both veth devices + * are in the same namespace + */ + if (peer_net == net) + goto out; + + /* notify on peer namespace new IFLA_LINK_NETNSID + * and IFLA_LINK values + */ + nsid = peernet2id_alloc(peer_net, net); + rtmsg_ifinfo_newnet(RTM_NEWLINK, peer, ~0U, GFP_ATOMIC, + &nsid, dev->ifindex); + ret = NOTIFY_OK; + +out: + rcu_read_unlock(); + + return ret; +} + +static struct notifier_block veth_notifier = { + .notifier_call = veth_notify, +}; + /* * init/fini */ static __init int veth_init(void) { - return rtnl_link_register(&veth_link_ops); + int err; + + err = register_netdevice_notifier(&veth_notifier); + if (err < 0) + return err; + + err = rtnl_link_register(&veth_link_ops); + if (err < 0) + unregister_netdevice_notifier(&veth_notifier); + + return err; } static __exit void veth_exit(void) { rtnl_link_unregister(&veth_link_ops); + unregister_netdevice_notifier(&veth_notifier); } module_init(veth_init);
--
2.17.1