Problem with bridges and wireless NIC's

Problem with bridges and wireless NIC's

[Bjarke Istrup Pedersen]

Hey,

There is a problem when trying to create a bridge containing a normal
NIC and a wireless NIC, and using hostapd.

The problem is, that it is not possible to create a bridge containing
a wireless NIC, if it hasn't been setup first.

Does anyone have a solution for this?

(The commit that introduced this problem is
ad4bb6f8883a13bb0f65b194dae36c62a02ac779 , reverting it solves the
problem).

For more info, please have a look at this bug report:
http://bugs.gentoo.org/show_bug.cgi?id=298824

Best regards,
Bjarke I. Pedersen

Re: Problem with bridges and wireless NIC's

[Jouni Malinen]

On Sun, Feb 28, 2010 at 11:58:10PM +0100, Bjarke Istrup Pedersen wrote:

> There is a problem when trying to create a bridge containing a normal
> NIC and a wireless NIC, and using hostapd.
> 
> The problem is, that it is not possible to create a bridge containing
> a wireless NIC, if it hasn't been setup first.
> 
> Does anyone have a solution for this?

How about first creating the br0, then starting hostapd, and finally
adding wlan0 into br0?

> (The commit that introduced this problem is
> ad4bb6f8883a13bb0f65b194dae36c62a02ac779 , reverting it solves the
> problem).

I don't know whether I would call that a solution, but well..

> For more info, please have a look at this bug report:
> http://bugs.gentoo.org/show_bug.cgi?id=298824

I'm not sure whether I understood the description correctly, but this
sounds like a limitation in the way the network setup is done. Forcing
br0 to be created with wlan0 before wlan0 has been configured is not
going to work. I would consider removing wlan0 from the static
configuration of br0 and just creating br0 with eth0 with the setup
scripts and allowing hostapd to add wlan0 into br0 once the interface
has been configured properly (support for this was added in hostapd
0.7.1).
 
-- 
Jouni Malinen                                            PGP id EFC895FA

Re: Problem with bridges and wireless NIC's

[Bjarke Istrup Pedersen]

2010/3/1 Jouni Malinen <j@w1.fi>:
> On Sun, Feb 28, 2010 at 11:58:10PM +0100, Bjarke Istrup Pedersen wrote:
>
>> There is a problem when trying to create a bridge containing a normal
>> NIC and a wireless NIC, and using hostapd.
>>
>> The problem is, that it is not possible to create a bridge containing
>> a wireless NIC, if it hasn't been setup first.
>>
>> Does anyone have a solution for this?
>
> How about first creating the br0, then starting hostapd, and finally
> adding wlan0 into br0?
>
>> (The commit that introduced this problem is
>> ad4bb6f8883a13bb0f65b194dae36c62a02ac779 , reverting it solves the
>> problem).
>
> I don't know whether I would call that a solution, but well..
>
>> For more info, please have a look at this bug report:
>> http://bugs.gentoo.org/show_bug.cgi?id=298824
>
> I'm not sure whether I understood the description correctly, but this
> sounds like a limitation in the way the network setup is done. Forcing
> br0 to be created with wlan0 before wlan0 has been configured is not
> going to work. I would consider removing wlan0 from the static
> configuration of br0 and just creating br0 with eth0 with the setup
> scripts and allowing hostapd to add wlan0 into br0 once the interface
> has been configured properly (support for this was added in hostapd
> 0.7.1).
>
> --
> Jouni Malinen                                            PGP id EFC895FA
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
>

Hey,

That sounds interresting, is there any chance that that functionality
can be added to the 0.6.x branch too? (I'm maintaining hostapd in
Gentoo, but cannot stabilize a 0.7.x build, due to it being a
development branch)

Best regards,
Bjarke I. Pedersen

Re: Problem with bridges and wireless NIC's

[Jouni Malinen]

On Mon, Mar 01, 2010 at 09:12:48AM +0100, Bjarke Istrup Pedersen wrote:
> That sounds interresting, is there any chance that that functionality
> can be added to the 0.6.x branch too? (I'm maintaining hostapd in
> Gentoo, but cannot stabilize a 0.7.x build, due to it being a
> development branch)

While it might be relatively simple to port the bridge setup code into
0.6.x, I'm not that keen on doing it for this particular reason. I'm
recommending 0.7.x branch for all AP functionality with nl80211-based
driver interface and as such, do not really want to promote use of 0.6.x
versions for this.

I started working on porting the driver_nl80211.c changes into the 0.6.x
branch, but that turned up to take way too much effort compared to what
the potential benefit would be. As such, I do not plan on continuing on
this direction and you should be prepared to quite a bit of additional
work on porting non-trivial fixes from hostapd 0.7.x yourself if you
plan on using hostapd 0.6.x in Gentoo with mac80211/nl80211-based
drivers.

-- 
Jouni Malinen                                            PGP id EFC895FA

Re: Problem with bridges and wireless NIC's

[Bjarke Istrup Pedersen]

2010/3/1 Jouni Malinen <j@w1.fi>:
> On Mon, Mar 01, 2010 at 09:12:48AM +0100, Bjarke Istrup Pedersen wrote:
>> That sounds interresting, is there any chance that that functionality
>> can be added to the 0.6.x branch too? (I'm maintaining hostapd in
>> Gentoo, but cannot stabilize a 0.7.x build, due to it being a
>> development branch)
>
> While it might be relatively simple to port the bridge setup code into
> 0.6.x, I'm not that keen on doing it for this particular reason. I'm
> recommending 0.7.x branch for all AP functionality with nl80211-based
> driver interface and as such, do not really want to promote use of 0.6.x
> versions for this.
>
> I started working on porting the driver_nl80211.c changes into the 0.6.x
> branch, but that turned up to take way too much effort compared to what
> the potential benefit would be. As such, I do not plan on continuing on
> this direction and you should be prepared to quite a bit of additional
> work on porting non-trivial fixes from hostapd 0.7.x yourself if you
> plan on using hostapd 0.6.x in Gentoo with mac80211/nl80211-based
> drivers.
>
> --
> Jouni Malinen                                            PGP id EFC895FA
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
>

Okay, so the best thing to do, is to advise people to reverse the
patch if the need 0.6.x, or use 0.7.x - right?
If so, thats fine with me :-)

Best regards,
Bjarke Istrup Pedersen

Re: Problem with bridges and wireless NIC's

[Jouni Malinen]

On Mon, Mar 01, 2010 at 12:40:14PM +0100, Bjarke Istrup Pedersen wrote:
> Okay, so the best thing to do, is to advise people to reverse the
> patch if the need 0.6.x, or use 0.7.x - right?

I don't think I would recommend people to reverse the commit that made
kernel reject invalid wlan0 mode in the bridge in general. It should be
possible to reorder network configuration to work with it and if really
not, reverting that change is reasonable only for a device that works as
an AP and uses bridging. Alternatively, whoever needs hostapd 0.6.x for
whatever reason could obviously also backport the hostapd patch for
bridge setup.

-- 
Jouni Malinen                                            PGP id EFC895FA

Re: Problem with bridges and wireless NIC's

[Bjarke Istrup Pedersen]

2010/3/1 Jouni Malinen <j@w1.fi>:
> On Mon, Mar 01, 2010 at 12:40:14PM +0100, Bjarke Istrup Pedersen wrote:
>> Okay, so the best thing to do, is to advise people to reverse the
>> patch if the need 0.6.x, or use 0.7.x - right?
>
> I don't think I would recommend people to reverse the commit that made
> kernel reject invalid wlan0 mode in the bridge in general. It should be
> possible to reorder network configuration to work with it and if really
> not, reverting that change is reasonable only for a device that works as
> an AP and uses bridging. Alternatively, whoever needs hostapd 0.6.x for
> whatever reason could obviously also backport the hostapd patch for
> bridge setup.
>
> --
> Jouni Malinen                                            PGP id EFC895FA
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
>

Okay, I have recommended people to upgrade to 0.7.1 and configure
hostapd to do the adding to the bridge :-)
Thanks for helping.

Btw. - is there a timeframe for when 0.7.x might go stable? (the WPS
stuff is really interresting) :-)