[NETFILTER]: nf_conntrack: support for layer 3 protocol load on demand

x_tables matches and targets that require nf_conntrack_ipv[4|6] to work
don't have enough information to load on demand these modules. This
patch introduces the following changes to solve this issue:

o nf_ct_l3proto_try_module_get: try to load the layer 3 connection
tracker module and increases the refcount.
o nf_ct_l3proto_module put: drop the refcount of the module.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index 2743c156caa0..b6f0905a4ee2 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -195,6 +195,10 @@ static inline void nf_ct_put(struct nf_conn *ct)
         nf_conntrack_put(&ct->ct_general);
 }
 
+/* Protocol module loading */
+extern int nf_ct_l3proto_try_module_get(unsigned short l3proto);
+extern void nf_ct_l3proto_module_put(unsigned short l3proto);
+
 extern struct nf_conntrack_tuple_hash *
 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
                     const struct nf_conn *ignored_conntrack);