batman-adv: add broadcast duplicate check

When multiple backbone gateways relay the same broadcast from the
backbone into the mesh, other nodes in the mesh may receive this
broadcast multiple times. To avoid this, the crc checksums of
received broadcasts are recorded and new broadcast packets with
the same content may be dropped if received by another gateway.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 1d1fd04c9c3a..78eddc9067e6 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -1076,6 +1076,10 @@ int recv_bcast_packet(struct sk_buff *skb, struct hard_iface *recv_if)
 
         spin_unlock_bh(&orig_node->bcast_seqno_lock);
 
+        /* check whether this has been sent by another originator before */
+        if (bla_check_bcast_duplist(bat_priv, bcast_packet, hdr_size))
+                goto out;
+
         /* rebroadcast packet */
         add_bcast_packet_to_list(bat_priv, skb, 1);