diff mbox

Move interface across network namespaces

Message ID m14o1e71qe.fsf@fess.ebiederm.org
State Not Applicable, archived
Delegated to: David Miller
Headers show

Commit Message

Eric W. Biederman Aug. 18, 2011, 11:12 p.m. UTC 
Renato Westphal <renatowestphal@gmail.com> writes:

> I forgot to mention that I'm using kernel v2.6.35 (with a lot of
> backports). For future reference, the commit 3b27e105550f7c4a ("netns:
> keep vlan slaves on master netns move", merged into v2.6.37-rc1) fixes
> this problem.

Which makes me silly as I now remember reviewing that patch.

>>>> * The target network namespace sends a RTM_NEWLINK netlink message
>>>> when an interface is moved to it. In the other hand, the source
>>>> network namespace doesn't sends a RTM_DELLINK message when an
>>>> interface is moved from it. This is very annoying because user space
>>>> applications (such as zebra) can't detect some interface moving
>>>> operations and then get into an inconsistent state. Anyone knows if
>>>> there's a workaround for this?
>>>
>>> Not getting RTM_DELLINK is a bug.  The device registration and
>>> unregistration code has changed since dev_change_net_namespace was
>>> written and apparently one of the changes failed to update
>>> dev_change_net_namespace.
>>>
>>
>> Good, that makes a lot more sense. In the kernel 2.6.32.43 the
>> RTM_DELLINK netlink message is sent when a network interface is moved
>> from a network namespace. The same doesn't happens in the kernel
>> 2.6.35.13. I'll try to isolate the problem some more.
>
> Well, this regression was introduced by commit a2835763e130c343ac,
> which was merged into v2.6.34. Reverting parts of this commit makes
> the problem go away but breaks the support of "specifying device flags
> during device creation". I don't know the best way to fix this... any
> ideas?

Everything going through dev_change_net_namespace already needs to be
in the initialized state.  So it looks like we just need to do:

Does the patch below work for you?

Eric

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Comments

Renato Westphal Aug. 19, 2011, 2:38 p.m. UTC | #1 
>> Well, this regression was introduced by commit a2835763e130c343ac,
>> which was merged into v2.6.34. Reverting parts of this commit makes
>> the problem go away but breaks the support of "specifying device flags
>> during device creation". I don't know the best way to fix this... any
>> ideas?
>
> Everything going through dev_change_net_namespace already needs to be
> in the initialized state.  So it looks like we just need to do:
>
> Does the patch below work for you?
>
> Eric
>
> ---
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 17d67b5..bfbde69 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -6108,6 +6108,8 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
>        call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
>        call_netdevice_notifiers(NETDEV_UNREGISTER_BATCH, dev);
>
> +       rtmsg_ifinfo(RTM_DELLINK, dev, ~0U);
> +
>        /*
>         *      Flush the unicast and multicast chains
>         */
>

 This works pretty fine. Thanks! :)
diff mbox

Patch

diff --git a/net/core/dev.c b/net/core/dev.c
index 17d67b5..bfbde69 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6108,6 +6108,8 @@  int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
 	call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
 	call_netdevice_notifiers(NETDEV_UNREGISTER_BATCH, dev);
 
+	rtmsg_ifinfo(RTM_DELLINK, dev, ~0U);
+
 	/*
 	 *	Flush the unicast and multicast chains
 	 */