Re: [HELP] netfilter Kconfig dependency nightmare

On Sat, Sep 17, 2005 at 01:08:58PM +0200, Roman Zippel wrote:

Hi,

Hi Roman, thanks for your reply.

On Sat, 17 Sep 2005, Harald Welte wrote:

quoted

ip_conntrack == CONFIG_IP_NF_CONNTRACK
nfnetlink == CONFIG_NETFILTER_NETLINK
ip_conntrack_netlink == CONFIG_IP_NF_CONNTRACK_NETLINK

If nfnetlink == N, ip_conntrack can be N or M or Y
If nfnetlink == M, ip_conntrack can be N or M
If nfnetlink == Y, ip_conntrack can be Y or M

Where is the requirement for the last one coming from?

sorry.  The last one should be N,M or Y.

The fundamental underlying problem is:

If CONFIG_IP_NF_CONNTRACK_NETLINK is selected (M or Y), then
CONFIG_IP_NF_CONNTRACK conditionally adds some code that references
symbols from nfnetlink.ko (CONFIG_NETFILTER_NETLINK)

So basically, enabling CONFIG_IP_NF_CONNTRACK_NETLINK creates a dependency
from CONFIG_IP_NF_CONNTRACK to CONFIG_NETFILTER_NETLINK.  AFAIK, the syntax
doesn't allow somthing like 

tristate IP_NF_CONNTRACK
	depends on NETFILTER_NETLINK if IP_NF_CONNTRACK_NETLINK!=n

So, if ip_conntrack_netlink == M (or Y), and ip_conntrack == Y, then
nfnetlink has to be set to Y (but cannot be a module).

Is there something that resembles 

And no, I do not see any chance to solve the problem in the code,
without either
1) adding yet another new module that only contains some 1kB of code and
   that requires additional EXPORT_SYMBOLS() on private data from
   ip_conntrack
or
2) adding dead code to ip_conntrack.ko that isn't used in many common
   configurations

:(

-- 
- Harald Welte [off-list ref]                 http://netfilter.org/
============================================================================
  "Fragmentation is like classful addressing -- an interesting early
   architectural error that shows how much experimentation was going
   on while IP was being designed."                    -- Paul Vixie