batman-adv: Fix rx packet/bytes stats on local ARP reply

The stats are generated by batadv_interface_stats and must not be stored
directly in the net_device stats member variable. The batadv_priv
bat_counters information is assembled when ndo_get_stats is called. The
stats previously stored in net_device::stats is then overwritten.

The batman-adv counters must therefore be increased when an ARP packet is
answered locally via the distributed arp table.

Fixes: c384ea3ec930 ("batman-adv: Distributed ARP Table - add snooping functions for ARP messages")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

net/batman-adv/distributed-arp-table.c

@@ -1064,8 +1064,9 @@ bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
 
 		skb_new->protocol = eth_type_trans(skb_new, soft_iface);
 
-		soft_iface->stats.rx_packets++;
-		soft_iface->stats.rx_bytes += skb->len + ETH_HLEN + hdr_size;
+		batadv_inc_counter(bat_priv, BATADV_CNT_RX);
+		batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
+				   skb->len + ETH_HLEN + hdr_size);
 
 		netif_rx(skb_new);
 		batadv_dbg(BATADV_DBG_DAT, bat_priv, "ARP request replied locally\n");