ipv4: Namespaceify tcp syncookies sysctl knob

Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 9e83084..ac000fc 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -101,6 +101,8 @@
 	int sysctl_tcp_syn_retries;
 	int sysctl_tcp_synack_retries;
 
+	int sysctl_tcp_syncookies;
+
 	struct ping_group_range ping_group_range;
 
 	atomic_t dev_addr_genid;