[IPV4] SNMP: Support OutMcastPkts and OutBcastPkts

A transmitted IP multicast datagram should be counted as OutMcastPkts.
By the same token, a transmitted IP broadcast datagram should be
counted as OutBcastPkts.
Signed-off-by: Mitsuru Chinen <mitch@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_output.c

@@ -160,9 +160,15 @@ EXPORT_SYMBOL_GPL(ip_build_and_send_pkt);
 static inline int ip_finish_output2(struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb->dst;
+	struct rtable *rt = (struct rtable *)dst;
 	struct net_device *dev = dst->dev;
 	int hh_len = LL_RESERVED_SPACE(dev);
 
+	if (rt->rt_type == RTN_MULTICAST)
+		IP_INC_STATS(IPSTATS_MIB_OUTMCASTPKTS);
+	else if (rt->rt_type == RTN_BROADCAST)
+		IP_INC_STATS(IPSTATS_MIB_OUTBCASTPKTS);
+
 	/* Be paranoid, rather than too clever. */
 	if (unlikely(skb_headroom(skb) < hh_len && dev->hard_header)) {
 		struct sk_buff *skb2;