bridge: only expire the mdb entry when query is received
Currently we arm the expire timer when the mdb entry is added,
however, this causes problem when there is no querier sent
out after that.
So we should only arm the timer when a corresponding query is
received, as suggested by Herbert.
And he also mentioned "if there is no querier then group
subscriptions shouldn't expire. There has to be at least one querier
in the network for this thing to work. Otherwise it just degenerates
into a non-snooping switch, which is OK."
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Adam Baker <linux@baker-net.org.uk>
Signed-off-by: Cong Wang <amwang@redhat.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 2475147..40bda80 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -617,8 +617,6 @@
mp->br = br;
mp->addr = *group;
- setup_timer(&mp->timer, br_multicast_group_expired,
- (unsigned long)mp);
hlist_add_head_rcu(&mp->hlist[mdb->ver], &mdb->mhash[hash]);
mdb->size++;
@@ -656,7 +654,6 @@
struct net_bridge_mdb_entry *mp;
struct net_bridge_port_group *p;
struct net_bridge_port_group __rcu **pp;
- unsigned long now = jiffies;
int err;
spin_lock(&br->multicast_lock);
@@ -671,7 +668,6 @@
if (!port) {
mp->mglist = true;
- mod_timer(&mp->timer, now + br->multicast_membership_interval);
goto out;
}
@@ -679,7 +675,7 @@
(p = mlock_dereference(*pp, br)) != NULL;
pp = &p->next) {
if (p->port == port)
- goto found;
+ goto out;
if ((unsigned long)p->port < (unsigned long)port)
break;
}
@@ -690,8 +686,6 @@
rcu_assign_pointer(*pp, p);
br_mdb_notify(br->dev, port, group, RTM_NEWMDB);
-found:
- mod_timer(&p->timer, now + br->multicast_membership_interval);
out:
err = 0;
@@ -1131,6 +1125,10 @@
if (!mp)
goto out;
+ setup_timer(&mp->timer, br_multicast_group_expired, (unsigned long)mp);
+ mod_timer(&mp->timer, now + br->multicast_membership_interval);
+ mp->timer_armed = true;
+
max_delay *= br->multicast_last_member_count;
if (mp->mglist &&
@@ -1205,6 +1203,10 @@
if (!mp)
goto out;
+ setup_timer(&mp->timer, br_multicast_group_expired, (unsigned long)mp);
+ mod_timer(&mp->timer, now + br->multicast_membership_interval);
+ mp->timer_armed = true;
+
max_delay *= br->multicast_last_member_count;
if (mp->mglist &&
(timer_pending(&mp->timer) ?
@@ -1263,7 +1265,7 @@
call_rcu_bh(&p->rcu, br_multicast_free_pg);
br_mdb_notify(br->dev, port, group, RTM_DELMDB);
- if (!mp->ports && !mp->mglist &&
+ if (!mp->ports && !mp->mglist && mp->timer_armed &&
netif_running(br->dev))
mod_timer(&mp->timer, jiffies);
}
@@ -1275,30 +1277,12 @@
br->multicast_last_member_interval;
if (!port) {
- if (mp->mglist &&
+ if (mp->mglist && mp->timer_armed &&
(timer_pending(&mp->timer) ?
time_after(mp->timer.expires, time) :
try_to_del_timer_sync(&mp->timer) >= 0)) {
mod_timer(&mp->timer, time);
}
-
- goto out;
- }
-
- for (p = mlock_dereference(mp->ports, br);
- p != NULL;
- p = mlock_dereference(p->next, br)) {
- if (p->port != port)
- continue;
-
- if (!hlist_unhashed(&p->mglist) &&
- (timer_pending(&p->timer) ?
- time_after(p->timer.expires, time) :
- try_to_del_timer_sync(&p->timer) >= 0)) {
- mod_timer(&p->timer, time);
- }
-
- break;
}
out:
@@ -1674,6 +1658,7 @@
hlist_for_each_entry_safe(mp, n, &mdb->mhash[i],
hlist[ver]) {
del_timer(&mp->timer);
+ mp->timer_armed = false;
call_rcu_bh(&mp->rcu, br_multicast_free_group);
}
}