From: Linus Lüssing linus.luessing@c0d3.blue
commit 938f2e0b57ffe8a6df71e1e177b2978b1b33fe5e upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/batman-adv/multicast.c | 15 ++++++++++----- net/batman-adv/multicast.h | 10 ++++++---- net/batman-adv/soft-interface.c | 7 +++++-- 3 files changed, 21 insertions(+), 11 deletions(-)
--- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -1373,6 +1373,7 @@ batadv_mcast_forw_rtr_node_get(struct ba * @bat_priv: the bat priv with all the soft interface information * @skb: The multicast packet to check * @orig: an originator to be set to forward the skb to + * @is_routable: stores whether the destination is routable * * Return: the forwarding mode as enum batadv_forw_mode and in case of * BATADV_FORW_SINGLE set the orig to the single originator the skb @@ -1380,17 +1381,16 @@ batadv_mcast_forw_rtr_node_get(struct ba */ enum batadv_forw_mode batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, - struct batadv_orig_node **orig) + struct batadv_orig_node **orig, int *is_routable) { int ret, tt_count, ip_count, unsnoop_count, total_count; bool is_unsnoopable = false; unsigned int mcast_fanout; struct ethhdr *ethhdr; - int is_routable = 0; int rtr_count = 0;
ret = batadv_mcast_forw_mode_check(bat_priv, skb, &is_unsnoopable, - &is_routable); + is_routable); if (ret == -ENOMEM) return BATADV_FORW_NONE; else if (ret < 0) @@ -1403,7 +1403,7 @@ batadv_mcast_forw_mode(struct batadv_pri ip_count = batadv_mcast_forw_want_all_ip_count(bat_priv, ethhdr); unsnoop_count = !is_unsnoopable ? 0 : atomic_read(&bat_priv->mcast.num_want_all_unsnoopables); - rtr_count = batadv_mcast_forw_rtr_count(bat_priv, is_routable); + rtr_count = batadv_mcast_forw_rtr_count(bat_priv, *is_routable);
total_count = tt_count + ip_count + unsnoop_count + rtr_count;
@@ -1723,6 +1723,7 @@ batadv_mcast_forw_want_rtr(struct batadv * @bat_priv: the bat priv with all the soft interface information * @skb: the multicast packet to transmit * @vid: the vlan identifier + * @is_routable: stores whether the destination is routable * * Sends copies of a frame with multicast destination to any node that signaled * interest in it, that is either via the translation table or the according @@ -1735,7 +1736,7 @@ batadv_mcast_forw_want_rtr(struct batadv * is neither IPv4 nor IPv6. NET_XMIT_SUCCESS otherwise. */ int batadv_mcast_forw_send(struct batadv_priv *bat_priv, struct sk_buff *skb, - unsigned short vid) + unsigned short vid, int is_routable) { int ret;
@@ -1751,12 +1752,16 @@ int batadv_mcast_forw_send(struct batadv return ret; }
+ if (!is_routable) + goto skip_mc_router; + ret = batadv_mcast_forw_want_rtr(bat_priv, skb, vid); if (ret != NET_XMIT_SUCCESS) { kfree_skb(skb); return ret; }
+skip_mc_router: consume_skb(skb); return ret; } --- a/net/batman-adv/multicast.h +++ b/net/batman-adv/multicast.h @@ -44,7 +44,8 @@ enum batadv_forw_mode {
enum batadv_forw_mode batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, - struct batadv_orig_node **mcast_single_orig); + struct batadv_orig_node **mcast_single_orig, + int *is_routable);
int batadv_mcast_forw_send_orig(struct batadv_priv *bat_priv, struct sk_buff *skb, @@ -52,7 +53,7 @@ int batadv_mcast_forw_send_orig(struct b struct batadv_orig_node *orig_node);
int batadv_mcast_forw_send(struct batadv_priv *bat_priv, struct sk_buff *skb, - unsigned short vid); + unsigned short vid, int is_routable);
void batadv_mcast_init(struct batadv_priv *bat_priv);
@@ -71,7 +72,8 @@ void batadv_mcast_purge_orig(struct bata
static inline enum batadv_forw_mode batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb, - struct batadv_orig_node **mcast_single_orig) + struct batadv_orig_node **mcast_single_orig, + int *is_routable) { return BATADV_FORW_ALL; } @@ -88,7 +90,7 @@ batadv_mcast_forw_send_orig(struct batad
static inline int batadv_mcast_forw_send(struct batadv_priv *bat_priv, struct sk_buff *skb, - unsigned short vid) + unsigned short vid, int is_routable) { kfree_skb(skb); return NET_XMIT_DROP; --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -200,6 +200,7 @@ static netdev_tx_t batadv_interface_tx(s 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;
@@ -302,7 +303,8 @@ static netdev_tx_t batadv_interface_tx(s 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;
@@ -367,7 +369,8 @@ send: 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))