bridge: implement multicast fast leave

V3: make it a flag
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>

include/uapi/linux/if_link.h

@@ -218,6 +218,7 @@ enum {
 	IFLA_BRPORT_MODE,	/* mode (hairpin)          */
 	IFLA_BRPORT_GUARD,	/* bpdu guard              */
 	IFLA_BRPORT_PROTECT,	/* root port protection    */
+	IFLA_BRPORT_FAST_LEAVE,	/* multicast fast leave    */
 	__IFLA_BRPORT_MAX
 };
 #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)

net/bridge/br_multicast.c

@@ -1225,7 +1225,7 @@ static void br_multicast_leave_group(struct net_bridge *br,
 	if (!mp)
 		goto out;
 
-	if (port && port->multicast_fast_leave) {
+	if (port && (port->flags & BR_MULTICAST_FAST_LEAVE)) {
 		struct net_bridge_port_group __rcu **pp;
 
 		for (pp = &mp->ports;

net/bridge/br_netlink.c

@@ -53,7 +53,8 @@ static int br_port_fill_attrs(struct sk_buff *skb,
 	    nla_put_u32(skb, IFLA_BRPORT_COST, p->path_cost) ||
 	    nla_put_u8(skb, IFLA_BRPORT_MODE, mode) ||
 	    nla_put_u8(skb, IFLA_BRPORT_GUARD, !!(p->flags & BR_BPDU_GUARD)) ||
-	    nla_put_u8(skb, IFLA_BRPORT_PROTECT, !!(p->flags & BR_ROOT_BLOCK)))
+	    nla_put_u8(skb, IFLA_BRPORT_PROTECT, !!(p->flags & BR_ROOT_BLOCK)) ||
+	    nla_put_u8(skb, IFLA_BRPORT_FAST_LEAVE, !!(p->flags & BR_MULTICAST_FAST_LEAVE)))
 		return -EMSGSIZE;
 
 	return 0;
@@ -210,6 +211,7 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[])
 
 	br_set_port_flag(p, tb, IFLA_BRPORT_MODE, BR_HAIRPIN_MODE);
 	br_set_port_flag(p, tb, IFLA_BRPORT_GUARD, BR_BPDU_GUARD);
+	br_set_port_flag(p, tb, IFLA_BRPORT_FAST_LEAVE, BR_MULTICAST_FAST_LEAVE);
 
 	if (tb[IFLA_BRPORT_COST]) {
 		err = br_stp_set_path_cost(p, nla_get_u32(tb[IFLA_BRPORT_COST]));

net/bridge/br_private.h

@@ -137,11 +137,11 @@ struct net_bridge_port
 #define BR_HAIRPIN_MODE		0x00000001
 #define BR_BPDU_GUARD           0x00000002
 #define BR_ROOT_BLOCK		0x00000004
+#define BR_MULTICAST_FAST_LEAVE	0x00000008
 
 #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;

net/bridge/br_sysfs_if.c

@@ -173,24 +173,7 @@ 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);
+BRPORT_ATTR_FLAG(multicast_fast_leave, BR_MULTICAST_FAST_LEAVE);
 #endif
 
 static const struct brport_attribute *brport_attrs[] = {