netfilter: nf_conntrack: add nf_ct_timeout_lookup

This patch adds the new nf_ct_timeout_lookup function to encapsulate
the timeout policy attachment that is called in the nf_conntrack_in
path.

Signed-off-by: Pablo Neira Ayuso <[e-mail]>

include/net/netfilter/nf_conntrack_timeout.h

···
 #endif
 };
 
+static inline unsigned int *
+nf_ct_timeout_lookup(struct net *net, struct nf_conn *ct,
+		     struct nf_conntrack_l4proto *l4proto)
+{
+#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
+	struct nf_conn_timeout *timeout_ext;
+	unsigned int *timeouts;
+
+	timeout_ext = nf_ct_timeout_find(ct);
+	if (timeout_ext)
+		timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext);
+	else
+		timeouts = l4proto->get_timeouts(net);
+
+	return timeouts;
+#else
+	return l4proto->get_timeouts(net);
+#endif
+}
+
 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 extern int nf_conntrack_timeout_init(struct net *net);
 extern void nf_conntrack_timeout_fini(struct net *net);

net/netfilter/nf_conntrack_core.c

···
 	enum ip_conntrack_info ctinfo;
 	struct nf_conntrack_l3proto *l3proto;
 	struct nf_conntrack_l4proto *l4proto;
-	struct nf_conn_timeout *timeout_ext;
 	unsigned int *timeouts;
 	unsigned int dataoff;
 	u_int8_t protonum;
···
 	NF_CT_ASSERT(skb->nfct);
 
 	/* Decide what timeout policy we want to apply to this flow. */
-	timeout_ext = nf_ct_timeout_find(ct);
-	if (timeout_ext)
-		timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext);
-	else
-		timeouts = l4proto->get_timeouts(net);
+	timeouts = nf_ct_timeout_lookup(net, ct, l4proto);
 
 	ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts);
 	if (ret <= 0) {