diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index abc84d9..16420cc 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -128,6 +128,7 @@ struct netns_ipv4 {
 	int sysctl_tcp_timestamps;
 	struct inet_timewait_death_row tcp_death_row;
 	int sysctl_max_syn_backlog;
+	int sysctl_tcp_fastopen;
 
 #ifdef CONFIG_NET_L3_MASTER_DEV
 	int sysctl_udp_l3mdev_accept;