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* [PATCH net] rtnetlink: allow to set iface down before enslaving it
@ 2023-12-29 10:08 Nicolas Dichtel
  2023-12-31 16:36 ` David Ahern
  2024-01-01 22:10 ` Phil Sutter
  0 siblings, 2 replies; 6+ messages in thread
From: Nicolas Dichtel @ 2023-12-29 10:08 UTC (permalink / raw)
  To: David S . Miller, Jakub Kicinski, Paolo Abeni, Eric Dumazet,
	Phil Sutter, David Ahern
  Cc: netdev, Nicolas Dichtel, stable

The below commit adds support for:
> ip link set dummy0 down
> ip link set dummy0 master bond0 up

but breaks the opposite:
> ip link set dummy0 up
> ip link set dummy0 master bond0 down

Let's add a workaround to have both commands working.

Cc: stable@vger.kernel.org
Fixes: a4abfa627c38 ("net: rtnetlink: Enslave device before bringing it up")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
---
 net/core/rtnetlink.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e8431c6c8490..dd79693c2d91 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2905,6 +2905,14 @@ static int do_setlink(const struct sk_buff *skb,
 		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
 	}
 
+	/* Backward compat: enable to set interface down before enslaving it */
+	if (!(ifm->ifi_flags & IFF_UP) && ifm->ifi_change & IFF_UP) {
+		err = dev_change_flags(dev, rtnl_dev_combine_flags(dev, ifm),
+				       extack);
+		if (err < 0)
+			goto errout;
+	}
+
 	if (tb[IFLA_MASTER]) {
 		err = do_set_master(dev, nla_get_u32(tb[IFLA_MASTER]), extack);
 		if (err)
-- 
2.39.2


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH net] rtnetlink: allow to set iface down before enslaving it
  2023-12-29 10:08 [PATCH net] rtnetlink: allow to set iface down before enslaving it Nicolas Dichtel
@ 2023-12-31 16:36 ` David Ahern
  2024-01-02 12:14   ` Nicolas Dichtel
  2024-01-01 22:10 ` Phil Sutter
  1 sibling, 1 reply; 6+ messages in thread
From: David Ahern @ 2023-12-31 16:36 UTC (permalink / raw)
  To: Nicolas Dichtel, David S . Miller, Jakub Kicinski, Paolo Abeni,
	Eric Dumazet, Phil Sutter
  Cc: netdev, stable

On 12/29/23 5:08 AM, Nicolas Dichtel wrote:
> The below commit adds support for:
>> ip link set dummy0 down
>> ip link set dummy0 master bond0 up
> 
> but breaks the opposite:
>> ip link set dummy0 up
>> ip link set dummy0 master bond0 down
> 
> Let's add a workaround to have both commands working.
> 
> Cc: stable@vger.kernel.org
> Fixes: a4abfa627c38 ("net: rtnetlink: Enslave device before bringing it up")
> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
> ---
>  net/core/rtnetlink.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 

add tests to tools/testing/selftests/net/rtnetlink.sh


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net] rtnetlink: allow to set iface down before enslaving it
  2023-12-29 10:08 [PATCH net] rtnetlink: allow to set iface down before enslaving it Nicolas Dichtel
  2023-12-31 16:36 ` David Ahern
@ 2024-01-01 22:10 ` Phil Sutter
  2024-01-02 12:14   ` Nicolas Dichtel
  1 sibling, 1 reply; 6+ messages in thread
From: Phil Sutter @ 2024-01-01 22:10 UTC (permalink / raw)
  To: Nicolas Dichtel
  Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, Eric Dumazet,
	David Ahern, netdev, stable

On Fri, Dec 29, 2023 at 11:08:35AM +0100, Nicolas Dichtel wrote:
> The below commit adds support for:
> > ip link set dummy0 down
> > ip link set dummy0 master bond0 up
> 
> but breaks the opposite:
> > ip link set dummy0 up
> > ip link set dummy0 master bond0 down
> 
> Let's add a workaround to have both commands working.
> 
> Cc: stable@vger.kernel.org
> Fixes: a4abfa627c38 ("net: rtnetlink: Enslave device before bringing it up")
> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
> ---
>  net/core/rtnetlink.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index e8431c6c8490..dd79693c2d91 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -2905,6 +2905,14 @@ static int do_setlink(const struct sk_buff *skb,
>  		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
>  	}
>  
> +	/* Backward compat: enable to set interface down before enslaving it */
> +	if (!(ifm->ifi_flags & IFF_UP) && ifm->ifi_change & IFF_UP) {
> +		err = dev_change_flags(dev, rtnl_dev_combine_flags(dev, ifm),
> +				       extack);
> +		if (err < 0)
> +			goto errout;
> +	}
> +
>  	if (tb[IFLA_MASTER]) {
>  		err = do_set_master(dev, nla_get_u32(tb[IFLA_MASTER]), extack);
>  		if (err)

Doesn't this merely revert to the old behaviour of setting the interface
up before enslaving if both IFF_UP and IFLA_MASTER are present? Did you
test this with a bond-type master?

Cheers, Phil

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net] rtnetlink: allow to set iface down before enslaving it
  2024-01-01 22:10 ` Phil Sutter
@ 2024-01-02 12:14   ` Nicolas Dichtel
  2024-01-02 22:03     ` Phil Sutter
  0 siblings, 1 reply; 6+ messages in thread
From: Nicolas Dichtel @ 2024-01-02 12:14 UTC (permalink / raw)
  To: Phil Sutter, David S . Miller, Jakub Kicinski, Paolo Abeni,
	Eric Dumazet, David Ahern, netdev, stable

Le 01/01/2024 à 23:10, Phil Sutter a écrit :
> On Fri, Dec 29, 2023 at 11:08:35AM +0100, Nicolas Dichtel wrote:
>> The below commit adds support for:
>>> ip link set dummy0 down
>>> ip link set dummy0 master bond0 up
>>
>> but breaks the opposite:
>>> ip link set dummy0 up
>>> ip link set dummy0 master bond0 down
>>
>> Let's add a workaround to have both commands working.
>>
>> Cc: stable@vger.kernel.org
>> Fixes: a4abfa627c38 ("net: rtnetlink: Enslave device before bringing it up")
>> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
>> ---
>>  net/core/rtnetlink.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
>> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
>> index e8431c6c8490..dd79693c2d91 100644
>> --- a/net/core/rtnetlink.c
>> +++ b/net/core/rtnetlink.c
>> @@ -2905,6 +2905,14 @@ static int do_setlink(const struct sk_buff *skb,
>>  		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
>>  	}
>>  
>> +	/* Backward compat: enable to set interface down before enslaving it */
>> +	if (!(ifm->ifi_flags & IFF_UP) && ifm->ifi_change & IFF_UP) {
>> +		err = dev_change_flags(dev, rtnl_dev_combine_flags(dev, ifm),
>> +				       extack);
>> +		if (err < 0)
>> +			goto errout;
>> +	}
>> +
>>  	if (tb[IFLA_MASTER]) {
>>  		err = do_set_master(dev, nla_get_u32(tb[IFLA_MASTER]), extack);
>>  		if (err)
> 
> Doesn't this merely revert to the old behaviour of setting the interface
> up before enslaving if both IFF_UP and IFLA_MASTER are present? Did you
> test this with a bond-type master?
Yes, both command sequences (cf commit log) work after the patch.
dev_change_flags() is called before do_set_master() only if the user asks to
remove the flag IFF_UP.


Regards,
Nicolas

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net] rtnetlink: allow to set iface down before enslaving it
  2023-12-31 16:36 ` David Ahern
@ 2024-01-02 12:14   ` Nicolas Dichtel
  0 siblings, 0 replies; 6+ messages in thread
From: Nicolas Dichtel @ 2024-01-02 12:14 UTC (permalink / raw)
  To: David Ahern, David S . Miller, Jakub Kicinski, Paolo Abeni,
	Eric Dumazet, Phil Sutter
  Cc: netdev, stable

Le 31/12/2023 à 17:36, David Ahern a écrit :
> On 12/29/23 5:08 AM, Nicolas Dichtel wrote:
>> The below commit adds support for:
>>> ip link set dummy0 down
>>> ip link set dummy0 master bond0 up
>>
>> but breaks the opposite:
>>> ip link set dummy0 up
>>> ip link set dummy0 master bond0 down
>>
>> Let's add a workaround to have both commands working.
>>
>> Cc: stable@vger.kernel.org
>> Fixes: a4abfa627c38 ("net: rtnetlink: Enslave device before bringing it up")
>> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
>> ---
>>  net/core/rtnetlink.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
> 
> add tests to tools/testing/selftests/net/rtnetlink.sh
> 
Will do.


Thanks,
Nicolas

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net] rtnetlink: allow to set iface down before enslaving it
  2024-01-02 12:14   ` Nicolas Dichtel
@ 2024-01-02 22:03     ` Phil Sutter
  0 siblings, 0 replies; 6+ messages in thread
From: Phil Sutter @ 2024-01-02 22:03 UTC (permalink / raw)
  To: Nicolas Dichtel
  Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, Eric Dumazet,
	David Ahern, netdev, stable

On Tue, Jan 02, 2024 at 01:14:21PM +0100, Nicolas Dichtel wrote:
> Le 01/01/2024 à 23:10, Phil Sutter a écrit :
> > On Fri, Dec 29, 2023 at 11:08:35AM +0100, Nicolas Dichtel wrote:
> >> The below commit adds support for:
> >>> ip link set dummy0 down
> >>> ip link set dummy0 master bond0 up
> >>
> >> but breaks the opposite:
> >>> ip link set dummy0 up
> >>> ip link set dummy0 master bond0 down
> >>
> >> Let's add a workaround to have both commands working.
> >>
> >> Cc: stable@vger.kernel.org
> >> Fixes: a4abfa627c38 ("net: rtnetlink: Enslave device before bringing it up")
> >> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
> >> ---
> >>  net/core/rtnetlink.c | 8 ++++++++
> >>  1 file changed, 8 insertions(+)
> >>
> >> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> >> index e8431c6c8490..dd79693c2d91 100644
> >> --- a/net/core/rtnetlink.c
> >> +++ b/net/core/rtnetlink.c
> >> @@ -2905,6 +2905,14 @@ static int do_setlink(const struct sk_buff *skb,
> >>  		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
> >>  	}
> >>  
> >> +	/* Backward compat: enable to set interface down before enslaving it */
> >> +	if (!(ifm->ifi_flags & IFF_UP) && ifm->ifi_change & IFF_UP) {
> >> +		err = dev_change_flags(dev, rtnl_dev_combine_flags(dev, ifm),
> >> +				       extack);
> >> +		if (err < 0)
> >> +			goto errout;
> >> +	}
> >> +
> >>  	if (tb[IFLA_MASTER]) {
> >>  		err = do_set_master(dev, nla_get_u32(tb[IFLA_MASTER]), extack);
> >>  		if (err)
> > 
> > Doesn't this merely revert to the old behaviour of setting the interface
> > up before enslaving if both IFF_UP and IFLA_MASTER are present? Did you
> > test this with a bond-type master?
> Yes, both command sequences (cf commit log) work after the patch.
> dev_change_flags() is called before do_set_master() only if the user asks to
> remove the flag IFF_UP.

Ah, indeed! I should have looked at rtnl_dev_combine_flags() before
commenting. When submitting v2, feel free to add my:

Acked-by: Phil Sutter <phil@nwl.cc>

Thanks, Phil

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2024-01-02 22:03 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-12-29 10:08 [PATCH net] rtnetlink: allow to set iface down before enslaving it Nicolas Dichtel
2023-12-31 16:36 ` David Ahern
2024-01-02 12:14   ` Nicolas Dichtel
2024-01-01 22:10 ` Phil Sutter
2024-01-02 12:14   ` Nicolas Dichtel
2024-01-02 22:03     ` Phil Sutter

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