netfilter: nf_conntrack: generalize nf_ct_l4proto_net

This patch generalizes nf_ct_l4proto_net by splitting it into chunks and
moving the corresponding protocol part to where it really belongs to.

To clarify, note that we follow two different approaches to support per-net
depending if it's built-in or run-time loadable protocol tracker.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Gao feng <gaofeng@cn.fujitsu.com>
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index 44f0da8..07e56ea 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -1623,6 +1623,11 @@
 	return ret;
 }
 
+static struct nf_proto_net *tcp_get_net_proto(struct net *net)
+{
+	return &net->ct.nf_ct_proto.tcp.pn;
+}
+
 struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp4 __read_mostly =
 {
 	.l3proto		= PF_INET,
@@ -1656,6 +1661,7 @@
 	},
 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 	.init_net		= tcp_init_net,
+	.get_net_proto		= tcp_get_net_proto,
 };
 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp4);
 
@@ -1692,5 +1698,6 @@
 	},
 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
 	.init_net		= tcp_init_net,
+	.get_net_proto		= tcp_get_net_proto,
 };
 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_tcp6);