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 <sbri...@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo.bianc...@redhat.com>
---
Changes since RFC:
- export rtmsg_ifinfo_build_skb() symbol and do not use rtmsg_ifinfo_newnet()
directly
---
drivers/net/veth.c | 66 +++++++++++++++++++++++++++++++++++++++++++-
net/core/rtnetlink.c | 1 +
2 files changed, 66 insertions(+), 1 deletion(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 8d679c8b7f25..0caffc93d74d 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -1242,18 +1242,82 @@ 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;
+ struct sk_buff *skb;
+
+ 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);
+ skb = rtmsg_ifinfo_build_skb(RTM_NEWLINK, peer, ~0U,
+ IFLA_EVENT_NONE, GFP_ATOMIC,
+ &nsid, dev->ifindex);
+ if (skb) {
+ rtnl_notify(skb, peer_net, 0, RTNLGRP_LINK, NULL,
+ GFP_ATOMIC);
+ 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);
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 24431e578310..b2df84db7670 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3326,6 +3326,7 @@ struct sk_buff *rtmsg_ifinfo_build_skb(int type, struct
net_device *dev,
rtnl_set_sk_err(net, RTNLGRP_LINK, err);
return NULL;
}
+EXPORT_SYMBOL(rtmsg_ifinfo_build_skb);
void rtmsg_ifinfo_send(struct sk_buff *skb, struct net_device *dev, gfp_t
flags)
{
--
2.17.1
