[IPV4]: Increment ipInHdrErrors when TTL expires.

Signed-off-by: Weidong <weid@nanjing-fnst.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_forward.c

@@ -116,6 +116,7 @@ int ip_forward(struct sk_buff *skb)
 
 too_many_hops:
         /* Tell the sender its packet died... */
+        IP_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
         icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, 0);
 drop:
 	kfree_skb(skb);