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Message-Id: <20220103171203.1124980-2-sw@simonwunderlich.de>
Date: Mon, 3 Jan 2022 18:12:03 +0100
From: Simon Wunderlich <sw@...onwunderlich.de>
To: davem@...emloft.net, kuba@...nel.org
Cc: netdev@...r.kernel.org, b.a.t.m.a.n@...ts.open-mesh.org,
Linus Lüssing <linus.luessing@...3.blue>,
Sven Eckelmann <sven@...fation.org>,
Simon Wunderlich <sw@...onwunderlich.de>
Subject: [PATCH 1/1] batman-adv: mcast: don't send link-local multicast to mcast routers
From: Linus Lüssing <linus.luessing@...3.blue>
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@...3.blue>
Signed-off-by: Sven Eckelmann <sven@...fation.org>
Signed-off-by: Simon Wunderlich <sw@...onwunderlich.de>
---
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(-)
diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index 433901dcf0c3..f4004cf0ff6f 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -1339,6 +1339,7 @@ batadv_mcast_forw_rtr_node_get(struct batadv_priv *bat_priv,
* @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
@@ -1346,17 +1347,16 @@ batadv_mcast_forw_rtr_node_get(struct batadv_priv *bat_priv,
*/
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)
@@ -1369,7 +1369,7 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb,
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;
@@ -1689,6 +1689,7 @@ batadv_mcast_forw_want_rtr(struct batadv_priv *bat_priv,
* @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
@@ -1701,7 +1702,7 @@ batadv_mcast_forw_want_rtr(struct batadv_priv *bat_priv,
* 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;
@@ -1717,12 +1718,16 @@ int batadv_mcast_forw_send(struct batadv_priv *bat_priv, struct sk_buff *skb,
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;
}
diff --git a/net/batman-adv/multicast.h b/net/batman-adv/multicast.h
index 9fee5da08311..8aec818d0bf6 100644
--- a/net/batman-adv/multicast.h
+++ b/net/batman-adv/multicast.h
@@ -43,7 +43,8 @@ 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,
@@ -51,7 +52,7 @@ int batadv_mcast_forw_send_orig(struct batadv_priv *bat_priv,
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);
@@ -68,7 +69,8 @@ void batadv_mcast_purge_orig(struct batadv_orig_node *orig_node);
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;
}
@@ -85,7 +87,7 @@ batadv_mcast_forw_send_orig(struct batadv_priv *bat_priv,
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;
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 7ee09337fc40..2dbbe6c19609 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))
--
2.30.2
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