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

[Daniel Lezcano <dlezcano@fr.ibm.com>]

Daniel Lezcano wrote:
> 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 ?

Another suggestion/question, is it acceptable to say non-gpl driver 
should use init_task.nsproxy->net_ns instead of &init_net ?

Or does it make sense to have init_net gpl-exported, since we can access 
it through init_task which is exported without gpl mention ?

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