diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 85b3e89..c573353 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1609,7 +1609,7 @@
 		return 0;
 	}
 
-	if (skb->len < (skb->h.th->doff<<2) || tcp_checksum_complete(skb))
+	if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
 		goto csum_err;
 
 	if (sk->sk_state == TCP_LISTEN) {