Revert "Revert "netfilter: synproxy: fix conntrackd interaction""

BugLink: http://bugs.launchpad.net/bugs/1709032

This reverts commit f58e6473.
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>

net/netfilter/nf_conntrack_netlink.c

@@ -45,6 +45,8 @@
 #include <net/netfilter/nf_conntrack_zones.h>
 #include <net/netfilter/nf_conntrack_timestamp.h>
 #include <net/netfilter/nf_conntrack_labels.h>
+#include <net/netfilter/nf_conntrack_seqadj.h>
+#include <net/netfilter/nf_conntrack_synproxy.h>
 #ifdef CONFIG_NF_NAT_NEEDED
 #include <net/netfilter/nf_nat_core.h>
 #include <net/netfilter/nf_nat_l4proto.h>
@@ -1798,6 +1800,8 @@ ctnetlink_create_conntrack(struct net *net,
 	nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
 	nf_ct_ecache_ext_add(ct, 0, 0, GFP_ATOMIC);
 	nf_ct_labels_ext_add(ct);
+	nfct_seqadj_ext_add(ct);
+	nfct_synproxy_ext_add(ct);
 
 	/* we must add conntrack extensions before confirmation. */
 	ct->status |= IPS_CONFIRMED;