ipv4: Namespaceify tcp synack retries 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 b7b5bd6..9e83084 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -99,6 +99,7 @@
 	int sysctl_tcp_keepalive_intvl;
 
 	int sysctl_tcp_syn_retries;
+	int sysctl_tcp_synack_retries;
 
 	struct ping_group_range ping_group_range;