[question] bridged tunnel

[question] bridged tunnel

[Jiri Pirko]

Hello all.

Imagine following net scheme:

LAN1 --- ROUTER A --- ROUTER B --- LAN2

I would like to have LAN1 and LAN2 bridged together.

I'm wondering if it's possible to made a tunnel and put it in bridge in
kernel space only? I would do the same with TAP and some dummy userspace
client/server but this would obviously decrease performance. Is it reasonable to
try to modify tun driver to be used not only via chardev but also via some
kernel API? This API would be used for other kernel modules to actually do the
communication.

Thanks for comments.

Jirka

Re: [question] bridged tunnel

[Rémi Denis-Courmont]

On Tuesday 28 July 2009 10:59:29 ext Jiri Pirko wrote:
> Hello all.
>
> Imagine following net scheme:
>
> LAN1 --- ROUTER A --- ROUTER B --- LAN2
>
> I would like to have LAN1 and LAN2 bridged together.

Then just put both interfaces to LAN1 and LAN2 in the same bridge... Why do 
you want to bring TAP here?!

-- 
Rémi Denis-Courmont
Nokia Devices R&D, Maemo Software, Helsinki

Re: [question] bridged tunnel

[Philip Craig]

Jiri Pirko wrote:
> Hello all.
> 
> Imagine following net scheme:
> 
> LAN1 --- ROUTER A --- ROUTER B --- LAN2
> 
> I would like to have LAN1 and LAN2 bridged together.

You can do that with gretap devices.

If you don't want to use GRE, then at least it provides an
example of how to do this in the kernel.

Re: [question] bridged tunnel

[Jiri Pirko]

Tue, Jul 28, 2009 at 10:11:15AM CEST, remi.denis-courmont@nokia.com wrote:
>On Tuesday 28 July 2009 10:59:29 ext Jiri Pirko wrote:
>> Hello all.
>>
>> Imagine following net scheme:
>>
>> LAN1 --- ROUTER A --- ROUTER B --- LAN2
>>
>> I would like to have LAN1 and LAN2 bridged together.
>
>Then just put both interfaces to LAN1 and LAN2 in the same bridge... Why do 
>you want to bring TAP here?!

Well generally there could be anything (e.g. internet) in between ROUTER A and
B. That's why.

>
>-- 
>Rémi Denis-Courmont
>Nokia Devices R&D, Maemo Software, Helsinki
>

Re: [question] bridged tunnel

[Jiri Pirko]

Tue, Jul 28, 2009 at 10:12:28AM CEST, philipc@snapgear.com wrote:
>Jiri Pirko wrote:
>> Hello all.
>> 
>> Imagine following net scheme:
>> 
>> LAN1 --- ROUTER A --- ROUTER B --- LAN2
>> 
>> I would like to have LAN1 and LAN2 bridged together.
>
>You can do that with gretap devices.
>
>If you don't want to use GRE, then at least it provides an
>example of how to do this in the kernel.

Will look at this. Thanks

Re: [question] bridged tunnel

[Philip Craig]

Jiri Pirko wrote:
> Well generally there could be anything (e.g. internet) in between ROUTER A and
> B. That's why.

If the internet is in the middle, then you don't want to invent your own
tunneling.  Using something like OpenVPN in tap mode, or gretap over IPSec.

Re: [question] bridged tunnel

[Jiri Pirko]

Tue, Jul 28, 2009 at 10:28:05AM CEST, philipc@snapgear.com wrote:
>Jiri Pirko wrote:
>> Well generally there could be anything (e.g. internet) in between ROUTER A and
>> B. That's why.
>
>If the internet is in the middle, then you don't want to invent your own
>tunneling.  Using something like OpenVPN in tap mode, or gretap over IPSec.
>

I would like to avoid overhead that openvpn and ipsec adds. In my case only few
routers are in the middle.