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

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
......@@ -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) {
......
......@@ -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:
......
......@@ -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);
......
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