batman-adv: Distributed ARP Table - add snooping functions for ARP messages
In case of an ARP message going in or out the soft_iface, it is intercepted and
a special action is performed. In particular the DHT helper functions previously
implemented are used to store all the ARP entries belonging to the network in
order to provide a fast and unicast lookup instead of the classic broadcast
flooding mechanism.
Each node stores the entries it is responsible for (following the DHT rules) in
its soft_iface ARP table. This makes it possible to reuse the kernel data
structures and functions for ARP management.
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 2f123a1..9dc0ae1 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -20,6 +20,7 @@
#include "main.h"
#include "soft-interface.h"
#include "hard-interface.h"
+#include "distributed-arp-table.h"
#include "routing.h"
#include "send.h"
#include "debugfs.h"
@@ -155,6 +156,7 @@
short vid __maybe_unused = -1;
bool do_bcast = false;
uint32_t seqno;
+ unsigned long brd_delay = 1;
if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
goto dropped;
@@ -224,6 +226,13 @@
if (!primary_if)
goto dropped;
+ /* in case of ARP request, we do not immediately broadcasti the
+ * packet, instead we first wait for DAT to try to retrieve the
+ * correct ARP entry
+ */
+ if (batadv_dat_snoop_outgoing_arp_request(bat_priv, skb))
+ brd_delay = msecs_to_jiffies(ARP_REQ_DELAY);
+
if (batadv_skb_head_push(skb, sizeof(*bcast_packet)) < 0)
goto dropped;
@@ -245,7 +254,7 @@
seqno = atomic_inc_return(&bat_priv->bcast_seqno);
bcast_packet->seqno = htonl(seqno);
- batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
+ batadv_add_bcast_packet_to_list(bat_priv, skb, brd_delay);
/* a copy is stored in the bcast list, therefore removing
* the original skb.
@@ -260,6 +269,11 @@
goto dropped;
}
+ if (batadv_dat_snoop_outgoing_arp_request(bat_priv, skb))
+ goto dropped;
+
+ batadv_dat_snoop_outgoing_arp_reply(bat_priv, skb);
+
ret = batadv_unicast_send_skb(bat_priv, skb);
if (ret != 0)
goto dropped_freed;