Re: [PATCH] netfilter: conntrack: add weak IPV6 dependency

[Pablo Neira Ayuso]

On Fri, Jul 06, 2018 at 08:35:48PM +0200, Florian Westphal wrote:
> Florian Westphal <fw@xxxxxxxxx> wrote:
> > Arnd Bergmann <arnd@xxxxxxxx> wrote:
> > > and that resulted in a new build failure:
> > > 
> > > net/netfilter/nf_conntrack_proto.o:(.rodata+0x788): undefined
> > > reference to `nf_conntrack_l4proto_icmpv6'
> > > net/ipv6/netfilter/nf_conntrack_reasm.o: In function `nf_ct_frag6_expire':
> > > nf_conntrack_reasm.c:(.text+0x2320): undefined reference to
> > > `ip6_expire_frag_queue'
> > > net/ipv6/netfilter/nf_conntrack_reasm.o: In function `nf_ct_frag6_init':
> > > nf_conntrack_reasm.c:(.text+0x2384): undefined reference to `ip6_frag_init'
> > > nf_conntrack_reasm.c:(.text+0x2394): undefined reference to `ip6_frag_init'
> > > nf_conntrack_reasm.c:(.text+0x2398): undefined reference to `ip6_rhash_params'
> > > net/ipv6/netfilter/nf_conntrack_reasm.o: In function `nf_ct_frag6_expire':
> > > nf_conntrack_reasm.c:(.text+0x10bc): undefined reference to
> > > `ip6_expire_frag_queue'
> > > 
> > > I don't think we can get CONFIG_NF_DEFRAG_IPV6=y to work with IPV6=m.
> > 
> > Yes, not with current implementation, but I still don't think this
> > is unavoidable.
> > 
> > In case this is urgent I'm fine with the patch that adds the dependency,
> > otherwise I'd like to try and disentangle nf_conntrack_reasm and ipv6.
> 
> This links fine for me with IPV6=m:
> 
> Pablo, do you think this is too ugly?

Well, yes...

> It requires some copypastry from ipv6 defrag into nfct ipv6 defrag
> to avoid the link errors outlined above.

This is a bit of a regression I think.

While I think a bit of demodularization is fine, if things like this
start to kick in, it's probably good if we go make a step back...

Let me know, thanks.