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Commit bcbfc778 authored by Linus Lüssing's avatar Linus Lüssing Committed by Greg Kroah-Hartman
Browse files

batman-adv: mcast: don't send link-local multicast to mcast routers 



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: 11d458c1 ("batman-adv: mcast: apply optimizations for routable packets, too")
Signed-off-by: default avatarLinus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarSimon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 76936ddb

net/batman-adv/multicast.c

+10 −5
Original line number Diff line number Diff line
@@ -1373,6 +1373,7 @@ 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
@@ -1380,17 +1381,16 @@ 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)
@@ -1403,7 +1403,7 @@ 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;
@@ -1723,6 +1723,7 @@ 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
@@ -1735,7 +1736,7 @@ 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;
@@ -1751,12 +1752,16 @@ 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;

}

net/batman-adv/multicast.h

+6 −4
Original line number Diff line number Diff line
@@ -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 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);
@@ -71,7 +72,8 @@ 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;

}
@@ -88,7 +90,7 @@ 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;

net/batman-adv/soft-interface.c

+5 −2
Original line number Diff line number Diff line
@@ -200,6 +200,7 @@ 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;
@@ -302,7 +303,8 @@ 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;
@@ -367,7 +369,8 @@ 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))