[PATCH 5.4 19/34] batman-adv: mcast: dont send link-local multicast to mcast routers
From: Greg Kroah-Hartman
Date: Mon Jan 10 2022 - 02:36:33 EST
From: Linus Lüssing <linus.luessing@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Sven Eckelmann <sven@xxxxxxxxxxxxx>
Signed-off-by: Simon Wunderlich <sw@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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))