Re: namespace support requires network modules to say "GPL"

Daniel Lezcano
2007-12-03T18:59:47Z

Ben Greear wrote:
> Eric W. Biederman wrote:
>> Patrick McHardy <kaber@trash.net> writes:
>>
>>
>>> Ben Greear wrote:
>>>
>>>> I have a binary module that uses dev_get_by_name...it's sort of a
>>>> bridge-like
>>>> thing and
>>>> needs user-space to tell it which device to listen for packets on...
>>>>
>>>> This code doesn't need or care about name-spaces, so I don't see how
>>>> it could
>>>> really
>>>> be infringing on the author's code (any worse than loading a binary
>>>> driver
>>>> into the kernel
>>>> ever does).
>>>>
>>
>> Regardless of infringement it is incompatible with a complete network
>> namespace implementation. Further it sounds like the module you are
>> describing defines a kernel ABI without being merged and hopes that
>> ABI will still be supportable in the future. Honestly I think doing so
>> is horrible code maintenance policy.
>>
> I don't mind if the ABI changes, so long as I can still use something
> similar.
>
> The namespace logic is interesting to me in general, but at this point I
> can't think of a way that
> it actually helps this particular module. All I really need is a way to
> grab every frame
> from eth0 and then transmit it to eth1. I'm currently doing this by
> finding the netdevice
> and registering a raw-packet protocol (ie, like tcpdump would do). At
> least up to 2.6.23,
> this does not require any hacks to the kernel and uses only non GPL
> exported symbols.
>
> Based on my understanding of the namespace logic, if I never add any
> namespaces,
> the general network layout should look similar to how it does today, so
> I should have
> no logical problem with my module.
>
>> Once things are largely complete it makes sense to argue with out of
>> tree module authors that because they don't have network namespace
>> support in their modules, their modules are broken.
> Does this imply that every module that accesses the network code *must*
> become
> GPL simply because it must interact with namespace logic that is
> exported as GPL only symbols?

That's right, with init_net's EXPORT_SYMBOL_GPL and dev_get_xx, we
enforce people to be GPL whatever they didn't asked to have the
namespaces in their code.

Eric, why can we simply change EXPORT_SYMBOL_GPL to EXPORT_SYMBOL for
init_net ?