xtables-addons - problem including nf_nat.h in userspace plugin

[Marek Kierdelewicz <marek@piasta.pl>]

Hi,

I'm writing a new netfilter module and I'm using xtables-addons
infrastructure version 1.31 as described in paragraph 2.9.1 of
"Writing Netfilter modules" ebook[1]. 

Iptables userspace plugin for the module needs definition of "struct
nf_nat_multi_range", so I added following line to libxt_xxxx.c:
#include <net/netfilter/nf_nat.h>

Unfortunately I get following message during make: 
warning: net/netfilter/nf_nat.h: No such file or directory
... and compilation fails.

I was able to make it work by copying nf_nat.h and nf_conntrack_tuple.h
to extension directory in xtables-addons tree and by modifying include
in libxt_xxxx.c to "nf_nat.h", but this doesn't seem to be the proper
way of doing things.

How can I make it work without copying header files to xtables-addons
tree?

Please CC me in reply as I'm not subscribed to netfilter-devel. Thx!

[1] http://jengelh.medozas.de/documents/Netfilter_Modules.pdf

Best regards,
Marek