bridge: implement multicast fast leave

V2: make the toggle per-port

Fast leave allows bridge to immediately stops the multicast
traffic on the port receives IGMP Leave when IGMP snooping is enabled,
no timeouts are observed.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 42 insertions, 0 deletions

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 241743417f49..2391bae4f733 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1225,6 +1225,27 @@ static void br_multicast_leave_group(struct net_bridge *br,
         if (!mp)
                 goto out;
 
+        if (port && port->multicast_fast_leave) {
+                struct net_bridge_port_group __rcu **pp;
+
+                for (pp = &mp->ports;
+                     (p = mlock_dereference(*pp, br)) != NULL;
+                     pp = &p->next) {
+                        if (p->port != port)
+                                continue;
+
+                        rcu_assign_pointer(*pp, p->next);
+                        hlist_del_init(&p->mglist);
+                        del_timer(&p->timer);
+                        call_rcu_bh(&p->rcu, br_multicast_free_pg);
+
+                        if (!mp->ports && !mp->mglist &&
+                            netif_running(br->dev))
+                                mod_timer(&mp->timer, jiffies);
+                }
+                goto out;
+        }
+
         now = jiffies;
         time = now + br->multicast_last_member_count *
                      br->multicast_last_member_interval;
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index eb9cd42146a5..cdbf9047a659 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -141,6 +141,7 @@ struct net_bridge_port
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
         u32                             multicast_startup_queries_sent;
         unsigned char                   multicast_router;
+        unsigned char                   multicast_fast_leave;
         struct timer_list               multicast_router_timer;
         struct timer_list               multicast_query_timer;
         struct hlist_head               mglist;
diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c
index 7ff95ba21982..dc484ace0be3 100644
--- a/net/bridge/br_sysfs_if.c
+++ b/net/bridge/br_sysfs_if.c
@@ -172,6 +172,25 @@ static int store_multicast_router(struct net_bridge_port *p,
 }
 static BRPORT_ATTR(multicast_router, S_IRUGO | S_IWUSR, show_multicast_router,
                    store_multicast_router);
+
+static ssize_t show_multicast_fast_leave(struct net_bridge_port *p,
+                                         char *buf)
+{
+        return sprintf(buf, "%d\n", p->multicast_fast_leave);
+}
+
+static int store_multicast_fast_leave(struct net_bridge_port *p,
+                                      unsigned long v)
+{
+        if (p->br->multicast_disabled)
+                return -EINVAL;
+
+        p->multicast_fast_leave = !!v;
+        return 0;
+}
+
+static BRPORT_ATTR(multicast_fast_leave, S_IRUGO | S_IWUSR,
+                   show_multicast_fast_leave, store_multicast_fast_leave);
 #endif
 
 static const struct brport_attribute *brport_attrs[] = {
@@ -195,6 +214,7 @@ static const struct brport_attribute *brport_attrs[] = {
         &brport_attr_root_block,
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
         &brport_attr_multicast_router,
+        &brport_attr_multicast_fast_leave,
 #endif
         NULL
 };