Messages in this thread | | | Date | Mon, 9 Jul 2018 22:27:25 +0200 | From | Florian Westphal <> | Subject | Re: [PATCH] netfilter: conntrack: add weak IPV6 dependency |
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Pablo Neira Ayuso <pablo@netfilter.org> wrote: > On Fri, Jul 06, 2018 at 08:35:48PM +0200, Florian Westphal wrote: > > Florian Westphal <fw@strlen.de> wrote: > > > Arnd Bergmann <arnd@arndb.de> 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.
nf_defrag_ipv6 has always depended on ipv6.
Previously dependency chain is
nf_conntrack_ipv6 -> ipv6 +-----> nf_defrag_ipv6 > ipv6 +-----> nf_conntrack
new dependency chain is: nf_conntrack --> nf_defrag_ipv6 --> ipv6
The alternate fix is the one from Arnd to disallow NF_CONNTRACK=y IPV6=m
> 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...
If you want to revert, ok. It will prevent all l4 unification patches plus any attempt to get rid of the nf_hook for defrag too however so I do not like it.
> Let me know, thanks.
Yet another alternative would be to remove the
nf_conntrack -> nf_defrag_ipv6
dependency, e.g. by adding a new rcu-protected function pointer.
nf_conntrack, when ipv6 conntrack is requested, would check if its null, and, if so, issue request_module() for ipv6 defrag before failing the request.
However, I find it even more ugly than my patch.
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