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author | Linus Lüssing <linus.luessing@web.de> | 2013-10-20 00:58:57 +0200 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2013-10-22 14:41:02 -0400 |
commit | 454594f3b93a49ef568cd190c5af31376b105a7b (patch) | |
tree | 5a3109ffdd29aed110e7cd5e4295dfe0246595fd /net/bridge/br_multicast.c | |
parent | 02cf4ebd82ff0ac7254b88e466820a290ed8289a (diff) | |
download | linux-stable-454594f3b93a49ef568cd190c5af31376b105a7b.tar.gz linux-stable-454594f3b93a49ef568cd190c5af31376b105a7b.tar.bz2 linux-stable-454594f3b93a49ef568cd190c5af31376b105a7b.zip |
Revert "bridge: only expire the mdb entry when query is received"
While this commit was a good attempt to fix issues occuring when no
multicast querier is present, this commit still has two more issues:
1) There are cases where mdb entries do not expire even if there is a
querier present. The bridge will unnecessarily continue flooding
multicast packets on the according ports.
2) Never removing an mdb entry could be exploited for a Denial of
Service by an attacker on the local link, slowly, but steadily eating up
all memory.
Actually, this commit became obsolete with
"bridge: disable snooping if there is no querier" (b00589af3b)
which included fixes for a few more cases.
Therefore reverting the following commits (the commit stated in the
commit message plus three of its follow up fixes):
====================
Revert "bridge: update mdb expiration timer upon reports."
This reverts commit f144febd93d5ee534fdf23505ab091b2b9088edc.
Revert "bridge: do not call setup_timer() multiple times"
This reverts commit 1faabf2aab1fdaa1ace4e8c829d1b9cf7bfec2f1.
Revert "bridge: fix some kernel warning in multicast timer"
This reverts commit c7e8e8a8f7a70b343ca1e0f90a31e35ab2d16de1.
Revert "bridge: only expire the mdb entry when query is received"
This reverts commit 9f00b2e7cf241fa389733d41b615efdaa2cb0f5b.
====================
CC: Cong Wang <amwang@redhat.com>
Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Reviewed-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bridge/br_multicast.c')
-rw-r--r-- | net/bridge/br_multicast.c | 47 |
1 files changed, 27 insertions, 20 deletions
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 1085f2180f3a..8b0b610ca2c9 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -272,7 +272,7 @@ static void br_multicast_del_pg(struct net_bridge *br, del_timer(&p->timer); call_rcu_bh(&p->rcu, br_multicast_free_pg); - if (!mp->ports && !mp->mglist && mp->timer_armed && + if (!mp->ports && !mp->mglist && netif_running(br->dev)) mod_timer(&mp->timer, jiffies); @@ -611,9 +611,6 @@ rehash: break; default: - /* If we have an existing entry, update it's expire timer */ - mod_timer(&mp->timer, - jiffies + br->multicast_membership_interval); goto out; } @@ -623,7 +620,6 @@ rehash: mp->br = br; mp->addr = *group; - setup_timer(&mp->timer, br_multicast_group_expired, (unsigned long)mp); @@ -663,6 +659,7 @@ static int br_multicast_add_group(struct net_bridge *br, 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); @@ -677,18 +674,15 @@ static int br_multicast_add_group(struct net_bridge *br, if (!port) { mp->mglist = true; + mod_timer(&mp->timer, now + br->multicast_membership_interval); goto out; } for (pp = &mp->ports; (p = mlock_dereference(*pp, br)) != NULL; pp = &p->next) { - if (p->port == port) { - /* We already have a portgroup, update the timer. */ - mod_timer(&p->timer, - jiffies + br->multicast_membership_interval); - goto out; - } + if (p->port == port) + goto found; if ((unsigned long)p->port < (unsigned long)port) break; } @@ -699,6 +693,8 @@ static int br_multicast_add_group(struct net_bridge *br, 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; @@ -1198,9 +1194,6 @@ static int br_ip4_multicast_query(struct net_bridge *br, if (!mp) goto out; - mod_timer(&mp->timer, now + br->multicast_membership_interval); - mp->timer_armed = true; - max_delay *= br->multicast_last_member_count; if (mp->mglist && @@ -1277,9 +1270,6 @@ static int br_ip6_multicast_query(struct net_bridge *br, if (!mp) goto out; - 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) ? @@ -1365,7 +1355,7 @@ static void br_multicast_leave_group(struct net_bridge *br, call_rcu_bh(&p->rcu, br_multicast_free_pg); br_mdb_notify(br->dev, port, group, RTM_DELMDB); - if (!mp->ports && !mp->mglist && mp->timer_armed && + if (!mp->ports && !mp->mglist && netif_running(br->dev)) mod_timer(&mp->timer, jiffies); } @@ -1377,12 +1367,30 @@ static void br_multicast_leave_group(struct net_bridge *br, br->multicast_last_member_interval; if (!port) { - if (mp->mglist && mp->timer_armed && + if (mp->mglist && (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: spin_unlock(&br->multicast_lock); @@ -1805,7 +1813,6 @@ void br_multicast_stop(struct net_bridge *br) 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); } } |