net: bridge: mcast: add support for group query retransmit

We need to be able to retransmit group-specific and group-and-source
specific queries. The new timer takes care of those.

v3: add IPv6 support
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/bridge/br_multicast.c

@@ -50,6 +50,7 @@ static void br_ip4_multicast_leave_group(struct net_bridge *br,
 					 __be32 group,
 					 __u16 vid,
 					 const unsigned char *src);
+static void br_multicast_port_group_rexmit(struct timer_list *t);
 
 static void __del_port_router(struct net_bridge_port *p);
 #if IS_ENABLED(CONFIG_IPV6)
@@ -184,6 +185,7 @@ void br_multicast_del_pg(struct net_bridge_mdb_entry *mp,
 	rcu_assign_pointer(*pp, pg->next);
 	hlist_del_init(&pg->mglist);
 	del_timer(&pg->timer);
+	del_timer(&pg->rexmit_timer);
 	hlist_for_each_entry_safe(ent, tmp, &pg->src_list, node)
 		br_multicast_del_group_src(ent);
 	br_mdb_notify(br->dev, pg->port, &pg->addr, RTM_DELMDB, pg->flags);
@@ -237,7 +239,8 @@ static struct sk_buff *br_ip4_multicast_alloc_query(struct net_bridge *br,
 						    struct net_bridge_port_group *pg,
 						    __be32 ip_dst, __be32 group,
 						    bool with_srcs, bool over_lmqt,
-						    u8 sflag, u8 *igmp_type)
+						    u8 sflag, u8 *igmp_type,
+						    bool *need_rexmit)
 {
 	struct net_bridge_port *p = pg ? pg->port : NULL;
 	struct net_bridge_group_src *ent;
@@ -352,6 +355,8 @@ static struct sk_buff *br_ip4_multicast_alloc_query(struct net_bridge *br,
 			    ent->src_query_rexmit_cnt > 0) {
 				ihv3->srcs[lmqt_srcs++] = ent->addr.u.ip4;
 				ent->src_query_rexmit_cnt--;
+				if (need_rexmit && ent->src_query_rexmit_cnt)
+					*need_rexmit = true;
 			}
 		}
 		if (WARN_ON(lmqt_srcs != ntohs(ihv3->nsrcs))) {
@@ -380,7 +385,8 @@ static struct sk_buff *br_ip6_multicast_alloc_query(struct net_bridge *br,
 						    const struct in6_addr *ip6_dst,
 						    const struct in6_addr *group,
 						    bool with_srcs, bool over_llqt,
-						    u8 sflag, u8 *igmp_type)
+						    u8 sflag, u8 *igmp_type,
+						    bool *need_rexmit)
 {
 	struct net_bridge_port *p = pg ? pg->port : NULL;
 	struct net_bridge_group_src *ent;
@@ -510,6 +516,8 @@ static struct sk_buff *br_ip6_multicast_alloc_query(struct net_bridge *br,
 			    ent->src_query_rexmit_cnt > 0) {
 				mld2q->mld2q_srcs[llqt_srcs++] = ent->addr.u.ip6;
 				ent->src_query_rexmit_cnt--;
+				if (need_rexmit && ent->src_query_rexmit_cnt)
+					*need_rexmit = true;
 			}
 		}
 		if (WARN_ON(llqt_srcs != ntohs(mld2q->mld2q_nsrcs))) {
@@ -540,7 +548,8 @@ static struct sk_buff *br_multicast_alloc_query(struct net_bridge *br,
 						struct br_ip *ip_dst,
 						struct br_ip *group,
 						bool with_srcs, bool over_lmqt,
-						u8 sflag, u8 *igmp_type)
+						u8 sflag, u8 *igmp_type,
+						bool *need_rexmit)
 {
 	__be32 ip4_dst;
 
@@ -550,7 +559,8 @@ static struct sk_buff *br_multicast_alloc_query(struct net_bridge *br,
 		return br_ip4_multicast_alloc_query(br, pg,
 						    ip4_dst, group->u.ip4,
 						    with_srcs, over_lmqt,
-						    sflag, igmp_type);
+						    sflag, igmp_type,
+						    need_rexmit);
 #if IS_ENABLED(CONFIG_IPV6)
 	case htons(ETH_P_IPV6): {
 		struct in6_addr ip6_dst;
@@ -564,7 +574,8 @@ static struct sk_buff *br_multicast_alloc_query(struct net_bridge *br,
 		return br_ip6_multicast_alloc_query(br, pg,
 						    &ip6_dst, &group->u.ip6,
 						    with_srcs, over_lmqt,
-						    sflag, igmp_type);
+						    sflag, igmp_type,
+						    need_rexmit);
 	}
 #endif
 	}
@@ -708,8 +719,9 @@ struct net_bridge_port_group *br_multicast_new_port_group(
 	p->filter_mode = filter_mode;
 	INIT_HLIST_HEAD(&p->src_list);
 	rcu_assign_pointer(p->next, next);
-	hlist_add_head(&p->mglist, &port->mglist);
 	timer_setup(&p->timer, br_multicast_port_group_expired, 0);
+	timer_setup(&p->rexmit_timer, br_multicast_port_group_rexmit, 0);
+	hlist_add_head(&p->mglist, &port->mglist);
 
 	if (src)
 		memcpy(p->eth_addr, src, ETH_ALEN);
@@ -943,7 +955,8 @@ static void __br_multicast_send_query(struct net_bridge *br,
 				      struct br_ip *ip_dst,
 				      struct br_ip *group,
 				      bool with_srcs,
-				      u8 sflag)
+				      u8 sflag,
+				      bool *need_rexmit)
 {
 	bool over_lmqt = !!sflag;
 	struct sk_buff *skb;
@@ -951,7 +964,8 @@ static void __br_multicast_send_query(struct net_bridge *br,
 
 again_under_lmqt:
 	skb = br_multicast_alloc_query(br, pg, ip_dst, group, with_srcs,
-				       over_lmqt, sflag, &igmp_type);
+				       over_lmqt, sflag, &igmp_type,
+				       need_rexmit);
 	if (!skb)
 		return;
 
@@ -1004,7 +1018,8 @@ static void br_multicast_send_query(struct net_bridge *br,
 	if (!other_query || timer_pending(&other_query->timer))
 		return;
 
-	__br_multicast_send_query(br, port, NULL, NULL, &br_group, false, 0);
+	__br_multicast_send_query(br, port, NULL, NULL, &br_group, false, 0,
+				  NULL);
 
 	time = jiffies;
 	time += own_query->startup_sent < br->multicast_startup_query_count ?
@@ -1049,6 +1064,44 @@ static void br_ip6_multicast_port_query_expired(struct timer_list *t)
 }
 #endif
 
+static void br_multicast_port_group_rexmit(struct timer_list *t)
+{
+	struct net_bridge_port_group *pg = from_timer(pg, t, rexmit_timer);
+	struct bridge_mcast_other_query *other_query = NULL;
+	struct net_bridge *br = pg->port->br;
+	bool need_rexmit = false;
+
+	spin_lock(&br->multicast_lock);
+	if (!netif_running(br->dev) || hlist_unhashed(&pg->mglist) ||
+	    !br_opt_get(br, BROPT_MULTICAST_ENABLED) ||
+	    !br_opt_get(br, BROPT_MULTICAST_QUERIER))
+		goto out;
+
+	if (pg->addr.proto == htons(ETH_P_IP))
+		other_query = &br->ip4_other_query;
+#if IS_ENABLED(CONFIG_IPV6)
+	else
+		other_query = &br->ip6_other_query;
+#endif
+
+	if (!other_query || timer_pending(&other_query->timer))
+		goto out;
+
+	if (pg->grp_query_rexmit_cnt) {
+		pg->grp_query_rexmit_cnt--;
+		__br_multicast_send_query(br, pg->port, pg, &pg->addr,
+					  &pg->addr, false, 1, NULL);
+	}
+	__br_multicast_send_query(br, pg->port, pg, &pg->addr,
+				  &pg->addr, true, 0, &need_rexmit);
+
+	if (pg->grp_query_rexmit_cnt || need_rexmit)
+		mod_timer(&pg->rexmit_timer, jiffies +
+					     br->multicast_last_member_interval);
+out:
+	spin_unlock(&br->multicast_lock);
+}
+
 static void br_mc_disabled_update(struct net_device *dev, bool value)
 {
 	struct switchdev_attr attr = {
@@ -1658,7 +1711,7 @@ br_multicast_leave_group(struct net_bridge *br,
 
 	if (br_opt_get(br, BROPT_MULTICAST_QUERIER)) {
 		__br_multicast_send_query(br, port, NULL, NULL, &mp->addr,
-					  false, 0);
+					  false, 0, NULL);
 
 		time = jiffies + br->multicast_last_member_count *
 				 br->multicast_last_member_interval;

net/bridge/br_private.h

@@ -240,10 +240,12 @@ struct net_bridge_port_group {
 	unsigned char			eth_addr[ETH_ALEN] __aligned(2);
 	unsigned char			flags;
 	unsigned char			filter_mode;
+	unsigned char			grp_query_rexmit_cnt;
 
 	struct hlist_head		src_list;
 	unsigned int			src_ents;
 	struct timer_list		timer;
+	struct timer_list		rexmit_timer;
 	struct hlist_node		mglist;
 
 	struct rcu_head			rcu;
@@ -868,6 +870,12 @@ static inline int br_multicast_igmp_type(const struct sk_buff *skb)
 {
 	return BR_INPUT_SKB_CB(skb)->igmp;
 }
+
+static inline unsigned long br_multicast_lmqt(const struct net_bridge *br)
+{
+	return br->multicast_last_member_interval *
+	       br->multicast_last_member_count;
+}
 #else
 static inline int br_multicast_rcv(struct net_bridge *br,
 				   struct net_bridge_port *port,