Re: [IPV6] addrconf: Fix IPv6 on tuntap tunnels

[David Miller <davem@davemloft.net>]

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Thu, 14 Jun 2007 18:16:07 +1000

> [IPV6] addrconf: Fix IPv6 on tuntap tunnels
> 
> The recent patch that added ipv6_hwtype is broken on tuntap tunnels.
> Indeed, it's broken on any device that does not pass the ipv6_hwtype
> test.
> 
> The reason is that the original test only applies to autoconfiguration,
> not IPv6 support.  IPv6 support is allowed on any device.  In fact,
> even with the ipv6_hwtype patch applied you can still add IPv6 addresses
> to any interface that doesn't pass thw ipv6_hwtype test provided that
> they have a sufficiently large MTU.  This is a serious problem because
> come deregistration time these devices won't be cleaned up properly.
> 
> I've gone back and looked at the rationale for the patch.  It appears
> that the real problem is that we were creating IPv6 devices even if the
> MTU was too small.  So here's a patch which fixes that and reverts the
> ipv6_hwtype stuff.
> 
> Thanks to Kanru Chen for reporting this issue.
> 
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Thanks for fixing this up Herbert.

Patch applied.