diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index d9e6cb3..c461628 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -285,7 +285,8 @@
 
 	if (skb->protocol == htons(ETH_P_IP))
 		proto = AF_INET;
-	else if (skb->protocol == htons(ETH_P_IPV6))
+	else if (skb->protocol == htons(ETH_P_IPV6) &&
+		 skb->sk->sk_family == AF_INET6)
 		proto = AF_INET6;
 	else
 		return;