Subject: Re: [PATCH] netfilter: fix dependency issues between IPv6 defragmentation and ip6tables

From: Florian Westphal <[email-masked]>
Date: Sun, 3 May 2015 13:07:15 +0200

Liu Hua <[email-masked]> wrote:
> commit f6318e558806c925029dc101f14874be9f9fa78f fix some related issue
> when ip6tables is enabled. But when IP6_NF_IPTABLES is disabled and
> NETFILTER_XT_TARGET_TPROXY is enabled. We will meet build failure with
> "net/built-in.o: In function `tproxy_tg_init':
> net/netfilter/xt_TPROXY.c:588: undefined reference to `nf_defrag_ipv6_enable'
> "
> So this patch change the Kconfig as ipv4 does.
> --- a/net/netfilter/Kconfig
> +++ b/net/netfilter/Kconfig
> @@ -865,7 +865,7 @@ config NETFILTER_XT_TARGET_TPROXY
>  	depends on (IPV6 || IPV6=n)
>  	depends on IP_NF_MANGLE
>  	select NF_DEFRAG_IPV4
> -	select NF_DEFRAG_IPV6 if IP6_NF_IPTABLES
> +	select NF_DEFRAG_IPV6

If IP6_NF_IPTABLES is not set, why would we have to pick
up IPV6 defragmentation?

Without ip6tables, TPROXY cannot be used for ipv6; in fact;
xt_TPROXY should be built without ipv6 support in this case.

My guess is that you have TPROXY=y but DEFRAG_IPV6=m, but that
might warrant a better fix (xt_socket seems to have same issue).