[PATCH 1/1] batman-adv: mcast: don't send link-local multicast to mcast routers
From: Simon Wunderlich <sw@simonwunderlich.de>
Date: 2022-01-03 17:20:35
Also in:
batman
Subsystem:
batman advanced, the rest · Maintainers:
Marek Lindner, Simon Wunderlich, Antonio Quartulli, Sven Eckelmann, Linus Torvalds
From: Linus Lüssing <redacted>
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 <redacted>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.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