DCCP: Fix to check missing sequence number for ICMP

If we want check the sequence number, the length of dccp packet must not less than __dccp_basic_hdr_len(dh). If the length of dccp packet is less than this value, check for sequence number will get unpredictable result.

This patch fix the problem.

---
 net/dccp/ipv4.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index 8fd4d57..0c5f82d 100644
@@ -207,7 +207,7 @@ static void dccp_v4_err(struct sk_buff *skb, u32 info)
 	int err;
 	struct net *net = dev_net(skb->dev);
 
-	if (skb->len < (iph->ihl << 2) + 8) {
+	if (skb->len < (iph->ihl << 2) + __dccp_basic_hdr_len(dh)) {
 		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
 		return;
 	}