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-rw-r--r--net/batman-adv/distributed-arp-table.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
index 28cfa53837e1..77ede40ff529 100644
--- a/net/batman-adv/distributed-arp-table.c
+++ b/net/batman-adv/distributed-arp-table.c
@@ -1203,6 +1203,7 @@ void batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv,
bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
struct sk_buff *skb, int hdr_size)
{
+ struct batadv_dat_entry *dat_entry = NULL;
u16 type;
__be32 ip_src, ip_dst;
u8 *hw_src, *hw_dst;
@@ -1225,12 +1226,41 @@ bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
hw_dst = batadv_arp_hw_dst(skb, hdr_size);
ip_dst = batadv_arp_ip_dst(skb, hdr_size);
+ /* If ip_dst is already in cache and has the right mac address,
+ * drop this frame if this ARP reply is destined for us because it's
+ * most probably an ARP reply generated by another node of the DHT.
+ * We have most probably received already a reply earlier. Delivering
+ * this frame would lead to doubled receive of an ARP reply.
+ */
+ dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_src, vid);
+ if (dat_entry && batadv_compare_eth(hw_src, dat_entry->mac_addr)) {
+ batadv_dbg(BATADV_DBG_DAT, bat_priv, "Doubled ARP reply removed: ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]; dat_entry: %pM-%pI4\n",
+ hw_src, &ip_src, hw_dst, &ip_dst,
+ dat_entry->mac_addr, &dat_entry->ip);
+ dropped = true;
+ goto out;
+ }
+
/* Update our internal cache with both the IP addresses the node got
* within the ARP reply
*/
batadv_dat_entry_add(bat_priv, ip_src, hw_src, vid);
batadv_dat_entry_add(bat_priv, ip_dst, hw_dst, vid);
+ /* If BLA is enabled, only forward ARP replies if we have claimed the
+ * source of the ARP reply or if no one else of the same backbone has
+ * already claimed that client. This prevents that different gateways
+ * to the same backbone all forward the ARP reply leading to multiple
+ * replies in the backbone.
+ */
+ if (!batadv_bla_check_claim(bat_priv, hw_src, vid)) {
+ batadv_dbg(BATADV_DBG_DAT, bat_priv,
+ "Device %pM claimed by another backbone gw. Drop ARP reply.\n",
+ hw_src);
+ dropped = true;
+ goto out;
+ }
+
/* if this REPLY is directed to a client of mine, let's deliver the
* packet to the interface
*/
@@ -1243,6 +1273,8 @@ bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
out:
if (dropped)
kfree_skb(skb);
+ if (dat_entry)
+ batadv_dat_entry_put(dat_entry);
/* if dropped == false -> deliver to the interface */
return dropped;
}