Re: [PATCH] ipv4: Disallow non-namespace aware protocols to register.

[ebiederm@xmission.com (Eric W. Biederman)]

David Miller <davem@davemloft.net> writes:

> From: ebiederm@xmission.com (Eric W. Biederman)
> Date: Thu, 14 Feb 2013 22:25:26 -0800
>
>> David Miller <davem@davemloft.net> writes:
>> 
>>> All in-tree ipv4 protocol implementations are now namespace
>>> aware.  Therefore all the run-time checks are superfluous.
>>>
>>> Reject registry of any non-namespace aware ipv4 protocol.
>>> Eventually we'll remove prot->netns_ok and this registry
>>> time check as well.
>> 
>> It has been a long time coming but this is very cool to see we have
>> finally made all of ipv4 network namespace aware.
>
> BTW, I took a look at ipv6 and unlike ipv4 there seems to be no sanity
> checks or per-protocol booleans indicating proper netns support.
>
> Is my interpretation right that ipv6 just assumes all registered
> protocols are netns aware at this point?

It looks like when the ipv6 network namespace work was done work that
check was not added to the ipv6 code :( I skimmed through the history
and I don't see any signs that anything was every done with struct
inet6_protocol.  Nor when I looked at the addition of netns support to
the ipv6 udp code were there any switches flipped.

> If so that was definitely a bug, because things like l2tp have an
> ipv6 component and were not fully netns aware until very recently.

Agreed it was a bug.

I have just read through all of the handlers registered with
inet6_add_protocol in my 3.8 development tree and it appears that
everything except l2tp has network namespace support.  And l2tp is fixed
in net-next so we appear to be good now.

Eric