batman-adv: mcast: don't send link-local multicast to mcast routers
The addition of routable multicast TX handling introduced a
bug/regression for packets with a link-local multicast destination:
These packets would be sent to all batman-adv nodes with a multicast
router and to all batman-adv nodes with an old version without multicast
router detection.
This even disregards the batman-adv multicast fanout setting, which can
potentially lead to an unwanted, high number of unicast transmissions or
even congestion.
Fixing this by avoiding to send link-local multicast packets to nodes in
the multicast router list.
Fixes: 11d458c1cb9b ("batman-adv: mcast: apply optimizations for routable packets, too")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 7ee0933..2dbbe6c 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -198,6 +198,7 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb,
int gw_mode;
enum batadv_forw_mode forw_mode = BATADV_FORW_SINGLE;
struct batadv_orig_node *mcast_single_orig = NULL;
+ int mcast_is_routable = 0;
int network_offset = ETH_HLEN;
__be16 proto;
@@ -300,7 +301,8 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb,
send:
if (do_bcast && !is_broadcast_ether_addr(ethhdr->h_dest)) {
forw_mode = batadv_mcast_forw_mode(bat_priv, skb,
- &mcast_single_orig);
+ &mcast_single_orig,
+ &mcast_is_routable);
if (forw_mode == BATADV_FORW_NONE)
goto dropped;
@@ -359,7 +361,8 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb,
ret = batadv_mcast_forw_send_orig(bat_priv, skb, vid,
mcast_single_orig);
} else if (forw_mode == BATADV_FORW_SOME) {
- ret = batadv_mcast_forw_send(bat_priv, skb, vid);
+ ret = batadv_mcast_forw_send(bat_priv, skb, vid,
+ mcast_is_routable);
} else {
if (batadv_dat_snoop_outgoing_arp_request(bat_priv,
skb))