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Commit 2ce297fc authored by Cong Wang's avatar Cong Wang Committed by David S. Miller
Browse files

bridge: fix seq check in br_mdb_dump() 



In case of rehashing, introduce a global variable 'br_mdb_rehash_seq'
which gets increased every time when rehashing, and assign
net->dev_base_seq + br_mdb_rehash_seq to cb->seq.

In theory cb->seq could be wrapped to zero, but this is not
easy to fix, as net->dev_base_seq is not visible inside
br_mdb_rehash(). In practice, this is rare.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarCong Wang <amwang@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2925f6c0

net/bridge/br_mdb.c

+2 −4
Original line number Diff line number Diff line
@@ -117,10 +117,8 @@ static int br_mdb_dump(struct sk_buff *skb, struct netlink_callback *cb) 


	rcu_read_lock();



	/* TODO: in case of rehashing, we need to check

	 * consistency for dumping.

	 */

	cb->seq = net->dev_base_seq;

	/* In theory this could be wrapped to 0... */

	cb->seq = net->dev_base_seq + br_mdb_rehash_seq;



	for_each_netdev_rcu(net, dev) {

		if (dev->priv_flags & IFF_EBRIDGE) {

net/bridge/br_multicast.c

+2 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
	rcu_dereference_protected(X, lockdep_is_held(&br->multicast_lock))



static void br_multicast_start_querier(struct net_bridge *br);

unsigned int br_mdb_rehash_seq;



#if IS_ENABLED(CONFIG_IPV6)

static inline int ipv6_is_transient_multicast(const struct in6_addr *addr)
@@ -338,6 +339,7 @@ static int br_mdb_rehash(struct net_bridge_mdb_htable __rcu **mdbp, int max, 
		return err;

	}



	br_mdb_rehash_seq++;

	call_rcu_bh(&mdb->rcu, br_mdb_free);



out:

net/bridge/br_private.h

+1 −0
Original line number Diff line number Diff line
@@ -411,6 +411,7 @@ extern int br_ioctl_deviceless_stub(struct net *net, unsigned int cmd, void __us 


/* br_multicast.c */

#ifdef CONFIG_BRIDGE_IGMP_SNOOPING

extern unsigned int br_mdb_rehash_seq;

extern int br_multicast_rcv(struct net_bridge *br,

			    struct net_bridge_port *port,

			    struct sk_buff *skb);