diff options
Diffstat (limited to 'net')
| -rw-r--r-- | net/bridge/br_multicast.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index b71772828b23..353406f2971a 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -192,6 +192,44 @@ struct net_bridge_mdb_entry *br_mdb_get(struct net_bridge_mcast *brmctx, return br_mdb_ip_get_rcu(br, &ip); } +/* IMPORTANT: this function must be used only when the contexts cannot be + * passed down (e.g. timer) and must be used for read-only purposes because + * the vlan snooping option can change, so it can return any context + * (non-vlan or vlan). Its initial intended purpose is to read timer values + * from the *current* context based on the option. At worst that could lead + * to inconsistent timers when the contexts are changed, i.e. src timer + * which needs to re-arm with a specific delay taken from the old context + */ +static struct net_bridge_mcast_port * +br_multicast_pg_to_port_ctx(const struct net_bridge_port_group *pg) +{ + struct net_bridge_mcast_port *pmctx = &pg->key.port->multicast_ctx; + struct net_bridge_vlan *vlan; + + lockdep_assert_held_once(&pg->key.port->br->multicast_lock); + + /* if vlan snooping is disabled use the port's multicast context */ + if (!pg->key.addr.vid || + !br_opt_get(pg->key.port->br, BROPT_MCAST_VLAN_SNOOPING_ENABLED)) + goto out; + + /* locking is tricky here, due to different rules for multicast and + * vlans we need to take rcu to find the vlan and make sure it has + * the BR_VLFLAG_MCAST_ENABLED flag set, it can only change under + * multicast_lock which must be already held here, so the vlan's pmctx + * can safely be used on return + */ + rcu_read_lock(); + vlan = br_vlan_find(nbp_vlan_group(pg->key.port), pg->key.addr.vid); + if (vlan && !br_multicast_port_ctx_vlan_disabled(&vlan->port_mcast_ctx)) + pmctx = &vlan->port_mcast_ctx; + else + pmctx = NULL; + rcu_read_unlock(); +out: + return pmctx; +} + static bool br_port_group_equal(struct net_bridge_port_group *p, struct net_bridge_port *port, const unsigned char *src) |