bridge: Limit number of MDB entries per port, port-vlan

The following patch will add two more maximum MDB allowances to the global one, mcast_hash_max, that exists today. In all these cases, attempts to add MDB entries above the configured maximums through netlink, fail noisily and obviously. Such visibility is missing when adding entries through the control plane traffic, by IGMP or MLD packets.

To improve visibility in those cases, add a trace point that reports the violation, including the relevant netdevice (be it a slave or the bridge itself), and the MDB entry parameters:

	# perf record -e bridge:br_mdb_full &
	# [...]
	# perf script | cut -d: -f4-
	 dev v2 af 2 src ::ffff:0.0.0.0 grp ::ffff:239.1.1.112/00:00:00:00:00:00 vid 0
	 dev v2 af 10 src :: grp ff0e::112/00:00:00:00:00:00 vid 0
	 dev v2 af 2 src ::ffff:0.0.0.0 grp ::ffff:239.1.1.112/00:00:00:00:00:00 vid 10
	 dev v2 af 10 src 2001:db8:1::1 grp ff0e::1/00:00:00:00:00:00 vid 10
	 dev v2 af 2 src ::ffff:192.0.2.1 grp ::ffff:239.1.1.1/00:00:00:00:00:00 vid 10

CC Steven Rostedt <[email protected]>

CC [email protected]

Signed-off-by Petr Machata <[email protected]>

---

Notes:
v2:
- Report IPv4 as an IPv6-mapped address through the IPv6 buffer as well, to save ring buffer space.

 include/trace/events/bridge.h | 58 +++++++++++++++++++++++++++++++++++
 net/core/net-traces.c         |  1 +
 2 files changed, 59 insertions(+)

The MDB maintained by the bridge is limited. When the bridge is configured for IGMP / MLD snooping, a buggy or malicious client can easily exhaust its capacity. In SW datapath, the capacity is configurable through the IFLA_BR_MCAST_HASH_MAX parameter, but ultimately is finite. Obviously a similar limit exists in the HW datapath for purposes of offloading.

In order to prevent the issue of unilateral exhaustion of MDB resources, introduce two parameters in each of two contexts:

- Per-port and per-port-VLAN number of MDB entries that the port is member in.

- Per-port and (when BROPT_MCAST_VLAN_SNOOPING_ENABLED is enabled) per-port-VLAN maximum permitted number of MDB entries, or 0 for no limit.

The per-port multicast context is used for tracking of MDB entries for the port as a whole. This is available for all bridges.

The per-port-VLAN multicast context is then only available on VLAN-filtering bridges on VLANs that have multicast snooping on.

With these changes in place, it will be possible to configure MDB limit for bridge as a whole, or any one port as a whole, or any single port-VLAN.

Note that unlike the global limit, exhaustion of the per-port and per-port-VLAN maximums does not cause disablement of multicast snooping. It is also permitted to configure the local limit larger than hash_max, even though that is not useful.

In this patch, introduce only the accounting for number of entries, and the max field itself, but not the means to toggle the max. The next patch introduces the netlink APIs to toggle and read the values.

Signed-off-by Petr Machata <[email protected]>

---

Notes:
v2:
- In br_multicast_port_ngroups_inc_one(), bounce if n>=max, not if n==max
- Adjust extack messages to mention ngroups, now that the bounces appear when n>=max, not n==max
- In __br_multicast_enable_port_ctx(), do not reset max to 0. Also do not count number of entries by going through _inc, as that would end up incorrectly bouncing the entries.

 net/bridge/br_multicast.c | 132 +++++++++++++++++++++++++++++++++++++-
 net/bridge/br_private.h   |   2 +
 2 files changed, 133 insertions(+), 1 deletion(-)

net/bridge/br_multicast.c +24 -0

index 51b622afdb67..e7ae339a8757 100644
@@ -31,6 +31,7 @@
 #include <net/ip6_checksum.h>
 #include <net/addrconf.h>
 #endif
+#include <trace/events/bridge.h>
 
 #include "br_private.h"
 #include "br_private_mcast_eht.h"

@@ -234,6 +235,29 @@ br_multicast_pg_to_port_ctx(const struct net_bridge_port_group *pg)
 	return pmctx;
 }
 
+static struct net_bridge_mcast_port *
+br_multicast_port_vid_to_port_ctx(struct net_bridge_port *port, u16 vid)
+{
+	struct net_bridge_mcast_port *pmctx = NULL;
+	struct net_bridge_vlan *vlan;
+
+	lockdep_assert_held_once(&port->br->multicast_lock);
+
+	if (!br_opt_get(port->br, BROPT_MCAST_VLAN_SNOOPING_ENABLED))
+		return NULL;
+
+	/* Take RCU to access the vlan. */
+	rcu_read_lock();
+
+	vlan = br_vlan_find(nbp_vlan_group_rcu(port), vid);
+	if (vlan && !br_multicast_port_ctx_vlan_disabled(&vlan->port_mcast_ctx))
+		pmctx = &vlan->port_mcast_ctx;
+
+	rcu_read_unlock();
+
+	return pmctx;
+}
+
 /* when snooping we need to check if the contexts should be used
  * in the following order:
  * - if pmctx is non-NULL (port), check if it should be used

net/bridge/br_multicast.c +7 -0

+}
+
+static int br_multicast_port_ngroups_inc(struct net_bridge_port *port,
+					 const struct br_ip *group,
+					 struct netlink_ext_ack *extack)
+{
+	struct net_bridge_mcast_port *pmctx;

net/bridge/br_multicast.c +9 -0

+		trace_br_mdb_full(port->dev, group);
+		return err;
+	}
+
+	/* Only count on the VLAN context if VID is given, and if snooping on
+	 * that VLAN is enabled.
+	 */
+	if (!group->vid)
+		return 0;

net/bridge/br_multicast.c +45 -1

+		trace_br_mdb_full(port->dev, group);
+		goto dec_one_out;
+	}
+
+	return 0;
+
+dec_one_out:
+	br_multicast_port_ngroups_dec_one(&port->multicast_ctx);
+	return err;
+}
+
+static void br_multicast_port_ngroups_dec(struct net_bridge_port *port, u16 vid)
+{
+	struct net_bridge_mcast_port *pmctx;
+
+	lockdep_assert_held_once(&port->br->multicast_lock);
+
+	if (vid) {
+		pmctx = br_multicast_port_vid_to_port_ctx(port, vid);
+		if (pmctx)
+			br_multicast_port_ngroups_dec_one(pmctx);
+	}
+	br_multicast_port_ngroups_dec_one(&port->multicast_ctx);
+}
+
 static void br_multicast_destroy_port_group(struct net_bridge_mcast_gc *gc)
 {
 	struct net_bridge_port_group *pg;

@@ -702,6 +802,7 @@ void br_multicast_del_pg(struct net_bridge_mdb_entry *mp,
 	} else {
 		br_multicast_star_g_handle_mode(pg, MCAST_INCLUDE);
 	}
+	br_multicast_port_ngroups_dec(pg->key.port, pg->key.addr.vid);
 	hlist_add_head(&pg->mcast_gc.gc_node, &br->mcast_gc_list);
 	queue_work(system_long_wq, &br->mcast_gc_work);
 

@@ -1165,6 +1266,7 @@ struct net_bridge_mdb_entry *br_multicast_new_group(struct net_bridge *br,
 		return mp;
 
 	if (atomic_read(&br->mdb_hash_tbl.nelems) >= br->hash_max) {
+		trace_br_mdb_full(br->dev, group);
 		br_mc_disabled_update(br->dev, false, NULL);
 		br_opt_toggle(br, BROPT_MULTICAST_ENABLED, false);
 		return ERR_PTR(-E2BIG);

@@ -1288,11 +1390,16 @@ struct net_bridge_port_group *br_multicast_new_port_group(
 			struct netlink_ext_ack *extack)
 {
 	struct net_bridge_port_group *p;
+	int err;
+
+	err = br_multicast_port_ngroups_inc(port, group, extack);
+	if (err)
+		return NULL;
 
 	p = kzalloc(sizeof(*p), GFP_ATOMIC);
 	if (unlikely(!p)) {
 		NL_SET_ERR_MSG_MOD(extack, "Couldn't allocate new port group");
-		return NULL;
+		goto dec_out;
 	}
 
 	p->key.addr = *group;

@@ -1326,18 +1433,22 @@ struct net_bridge_port_group *br_multicast_new_port_group(
 
 free_out:
 	kfree(p);
+dec_out:
+	br_multicast_port_ngroups_dec(port, group->vid);
 	return NULL;
 }
 
 void br_multicast_del_port_group(struct net_bridge_port_group *p)
 {
 	struct net_bridge_port *port = p->key.port;
+	__u16 vid = p->key.addr.vid;
 
 	hlist_del_init(&p->mglist);
 	if (!br_multicast_is_star_g(&p->key.addr))
 		rhashtable_remove_fast(&port->br->sg_port_tbl, &p->rhnode,
 				       br_sg_port_rht_params);
 	kfree(p);
+	br_multicast_port_ngroups_dec(port, vid);
 }
 
 void br_multicast_host_join(const struct net_bridge_mcast *brmctx,

@@ -1951,6 +2062,25 @@ static void __br_multicast_enable_port_ctx(struct net_bridge_mcast_port *pmctx)
 		br_ip4_multicast_add_router(brmctx, pmctx);
 		br_ip6_multicast_add_router(brmctx, pmctx);
 	}
+
+	if (br_multicast_port_ctx_is_vlan(pmctx)) {
+		struct net_bridge_port_group *pg;
+		u32 n = 0;
+
+		/* The mcast_n_groups counter might be wrong. First,
+		 * BR_VLFLAG_MCAST_ENABLED is toggled before temporary entries
+		 * are flushed, thus mcast_n_groups after the toggle does not

net/bridge/br_multicast.c +1 -0

+	}
 }
 
 void br_multicast_enable_port(struct net_bridge_port *port)

net/bridge/br_private.h +2 -0

index e4069e27b5c6..49f411a0a1f1 100644
@@ -126,6 +126,8 @@ struct net_bridge_mcast_port {
 	struct hlist_node		ip6_rlist;
 #endif /* IS_ENABLED(CONFIG_IPV6) */
 	unsigned char			multicast_router;
+	u32				mdb_n_entries;
+	u32				mdb_max_entries;
 #endif /* CONFIG_BRIDGE_IGMP_SNOOPING */
 };
 

Quoted 95 lines · Petr Machata

The MDB maintained by the bridge is limited. When the bridge is configured for IGMP / MLD snooping, a buggy or malicious client can easily exhaust its capacity. In SW datapath, the capacity is configurable through the IFLA_BR_MCAST_HASH_MAX parameter, but ultimately is finite. Obviously a similar limit exists in the HW datapath for purposes of offloading.

In order to prevent the issue of unilateral exhaustion of MDB resources, introduce two parameters in each of two contexts:

- Per-port and per-port-VLAN number of MDB entries that the port is member in.

- Per-port and (when BROPT_MCAST_VLAN_SNOOPING_ENABLED is enabled) per-port-VLAN maximum permitted number of MDB entries, or 0 for no limit.

The per-port multicast context is used for tracking of MDB entries for the port as a whole. This is available for all bridges.

The per-port-VLAN multicast context is then only available on VLAN-filtering bridges on VLANs that have multicast snooping on.

With these changes in place, it will be possible to configure MDB limit for bridge as a whole, or any one port as a whole, or any single port-VLAN.

Note that unlike the global limit, exhaustion of the per-port and per-port-VLAN maximums does not cause disablement of multicast snooping. It is also permitted to configure the local limit larger than hash_max, even though that is not useful.

In this patch, introduce only the accounting for number of entries, and the max field itself, but not the means to toggle the max. The next patch introduces the netlink APIs to toggle and read the values.

Signed-off-by Petr Machata <[email protected]>

---

Notes:
v2:
- In br_multicast_port_ngroups_inc_one(), bounce if n>=max, not if n==max
- Adjust extack messages to mention ngroups, now that the bounces appear when n>=max, not n==max
- In __br_multicast_enable_port_ctx(), do not reset max to 0. Also do not count number of entries by going through _inc, as that would end up incorrectly bouncing the entries.

 net/bridge/br_multicast.c | 132 +++++++++++++++++++++++++++++++++++++-
 net/bridge/br_private.h   |   2 +
 2 files changed, 133 insertions(+), 1 deletion(-)

net/bridge/br_multicast.c +24 -0

index 51b622afdb67..e7ae339a8757 100644
@@ -31,6 +31,7 @@
 #include <net/ip6_checksum.h>
 #include <net/addrconf.h>
 #endif
+#include <trace/events/bridge.h>
 
 #include "br_private.h"
 #include "br_private_mcast_eht.h"

@@ -234,6 +235,29 @@ br_multicast_pg_to_port_ctx(const struct net_bridge_port_group *pg)
 	return pmctx;
 }
 
+static struct net_bridge_mcast_port *
+br_multicast_port_vid_to_port_ctx(struct net_bridge_port *port, u16 vid)
+{
+	struct net_bridge_mcast_port *pmctx = NULL;
+	struct net_bridge_vlan *vlan;
+
+	lockdep_assert_held_once(&port->br->multicast_lock);
+
+	if (!br_opt_get(port->br, BROPT_MCAST_VLAN_SNOOPING_ENABLED))
+		return NULL;
+
+	/* Take RCU to access the vlan. */
+	rcu_read_lock();
+
+	vlan = br_vlan_find(nbp_vlan_group_rcu(port), vid);
+	if (vlan && !br_multicast_port_ctx_vlan_disabled(&vlan->port_mcast_ctx))
+		pmctx = &vlan->port_mcast_ctx;
+
+	rcu_read_unlock();
+
+	return pmctx;
+}
+
 /* when snooping we need to check if the contexts should be used
  * in the following order:
  * - if pmctx is non-NULL (port), check if it should be used

net/bridge/br_multicast.c void br_multicast_del_group_src(struct net_bridge_group_src *src, · line 700

Quoted 9 lines

net/bridge/br_multicast.c +6 -0

@@ -668,6 +692,82 @@ void br_multicast_del_group_src(struct net_bridge_group_src *src,
 	__br_multicast_del_group_src(src);
 }
 
+static int
+br_multicast_port_ngroups_inc_one(struct net_bridge_mcast_port *pmctx,
+				  struct netlink_ext_ack *extack)
+{
+	if (pmctx->mdb_max_entries &&
+	    pmctx->mdb_n_entries >= pmctx->mdb_max_entries)

These should be using *_ONCE() because of the next patch. KCSAN might be sad otherwise. :)

net/bridge/br_multicast.c void br_multicast_del_group_src(struct net_bridge_group_src *src, · line 703

Quoted 3 lines

net/bridge/br_multicast.c +3 -0

+		return -E2BIG;
+
+	pmctx->mdb_n_entries++;

WRITE_ONCE()

net/bridge/br_multicast.c void br_multicast_del_group_src(struct net_bridge_group_src *src, · line 709

Quoted 6 lines

net/bridge/br_multicast.c +6 -0

+	return 0;
+}
+
+static void br_multicast_port_ngroups_dec_one(struct net_bridge_mcast_port *pmctx)
+{
+	WARN_ON_ONCE(pmctx->mdb_n_entries-- == 0);

READ_ONCE()

Quoted 3 lines

net/bridge/br_multicast.c +2 -0

+}
+

Quoted 4 lines · Petr Machata

net/bridge/br_multicast.c +0 -0

@@ -668,6 +692,82 @@ void br_multicast_del_group_src(struct net_bridge_group_src *src,
 	__br_multicast_del_group_src(src);
 }
 

net/bridge/br_multicast.c void br_multicast_del_group_src(struct net_bridge_group_src *src, · line 700

Quoted 6 lines

net/bridge/br_multicast.c +6 -0

+static int
+br_multicast_port_ngroups_inc_one(struct net_bridge_mcast_port *pmctx,
+				  struct netlink_ext_ack *extack)
+{
+	if (pmctx->mdb_max_entries &&
+	    pmctx->mdb_n_entries >= pmctx->mdb_max_entries)

These should be using *_ONCE() because of the next patch. KCSAN might be sad otherwise. :)

The previous patch added accounting for number of MDB entries per port and per port-VLAN, and the logic to verify that these values stay within configured bounds. However it didn't provide means to actually configure those bounds or read the occupancy. This patch does that.

Two new netlink attributes are added for the MDB occupancy:
IFLA_BRPORT_MCAST_N_GROUPS for the per-port occupancy and BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS for the per-port-VLAN occupancy. And another two for the maximum number of MDB entries:
IFLA_BRPORT_MCAST_MAX_GROUPS for the per-port maximum, and BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS for the per-port-VLAN one.

Note that the two new IFLA_BRPORT_ attributes prompt bumping of RTNL_SLAVE_MAX_TYPE to size the slave attribute tables large enough.

The new attributes are used like this:

 # ip link add name br up type bridge vlan_filtering 1 mcast_snooping 1 \
                                      mcast_vlan_snooping 1 mcast_querier 1
 # ip link set dev v1 master br
 # bridge vlan add dev v1 vid 2

 # bridge vlan set dev v1 vid 1 mcast_max_groups 1
 # bridge mdb add dev br port v1 grp 230.1.2.3 temp vid 1
 # bridge mdb add dev br port v1 grp 230.1.2.4 temp vid 1
 Error: bridge: Port-VLAN is already a member in mcast_max_groups (1) groups.

 # bridge link set dev v1 mcast_max_groups 1
 # bridge mdb add dev br port v1 grp 230.1.2.3 temp vid 2
 Error: bridge: Port is already a member in mcast_max_groups (1) groups.

 # bridge -d link show
 5: v1@v2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master br [...]
     [...] mcast_n_groups 1 mcast_max_groups 1

 # bridge -d vlan show
 port              vlan-id
 br                1 PVID Egress Untagged
                     state forwarding mcast_router 1
 v1                1 PVID Egress Untagged
                     [...] mcast_n_groups 1 mcast_max_groups 1
                   2
                     [...] mcast_n_groups 0 mcast_max_groups 0

Signed-off-by Petr Machata <[email protected]>

---

Notes:

    v2:
    - Drop locks around accesses in
      br_multicast_{port,vlan}_ngroups_{get,set_max}(),
    - Drop bounces due to max<n in
      br_multicast_{port,vlan}_ngroups_set_max().

 include/uapi/linux/if_bridge.h |  2 ++
 include/uapi/linux/if_link.h   |  2 ++
 net/bridge/br_multicast.c      | 50 ++++++++++++++++++++++++++++++++++
 net/bridge/br_netlink.c        | 17 +++++++++++-
 net/bridge/br_private.h        | 15 +++++++++-
 net/bridge/br_vlan.c           | 11 +++++---
 net/bridge/br_vlan_options.c   | 33 +++++++++++++++++++++-
 net/core/rtnetlink.c           |  2 +-
 8 files changed, 124 insertions(+), 8 deletions(-)

include/uapi/linux/if_bridge.h +2 -0

index d9de241d90f9..d60c456710b3 100644
@@ -523,6 +523,8 @@ enum {
 	BRIDGE_VLANDB_ENTRY_TUNNEL_INFO,
 	BRIDGE_VLANDB_ENTRY_STATS,
 	BRIDGE_VLANDB_ENTRY_MCAST_ROUTER,
+	BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS,
+	BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS,
 	__BRIDGE_VLANDB_ENTRY_MAX,
 };
 #define BRIDGE_VLANDB_ENTRY_MAX (__BRIDGE_VLANDB_ENTRY_MAX - 1)

include/uapi/linux/if_link.h +2 -0

index 1021a7e47a86..1bed3a72939c 100644
@@ -564,6 +564,8 @@ enum {
 	IFLA_BRPORT_MCAST_EHT_HOSTS_CNT,
 	IFLA_BRPORT_LOCKED,
 	IFLA_BRPORT_MAB,
+	IFLA_BRPORT_MCAST_N_GROUPS,
+	IFLA_BRPORT_MCAST_MAX_GROUPS,
 	__IFLA_BRPORT_MAX
 };
 #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)

net/bridge/br_multicast.c +1 -0

index e7ae339a8757..393ffc21c3e8 100644
@@ -768,6 +768,56 @@ static void br_multicast_port_ngroups_dec(struct net_bridge_port *port, u16 vid)
 	br_multicast_port_ngroups_dec_one(&port->multicast_ctx);
 }
 
+u32 br_multicast_port_ngroups_get(const struct net_bridge_port *port)

net/bridge/br_multicast.c +8 -0

+
+	*n = READ_ONCE(v->port_mcast_ctx.mdb_n_entries);
+	return 0;
+}
+
+void br_multicast_port_ngroups_set_max(struct net_bridge_port *port, u32 max)
+{
+	WRITE_ONCE(port->multicast_ctx.mdb_max_entries, max);

net/bridge/br_multicast.c +10 -0

+
+	WRITE_ONCE(v->port_mcast_ctx.mdb_max_entries, max);
+	return 0;
+}
+
+u32 br_multicast_port_ngroups_get_max(const struct net_bridge_port *port)
+{
+	return READ_ONCE(port->multicast_ctx.mdb_max_entries);
+}
+

net/bridge/br_multicast.c +1 -0

+
 static void br_multicast_destroy_port_group(struct net_bridge_mcast_gc *gc)
 {
 	struct net_bridge_port_group *pg;

net/bridge/br_netlink.c +16 -1

index a6133d469885..968d0963d9a9 100644
@@ -202,6 +202,8 @@ static inline size_t br_port_info_size(void)
 		+ nla_total_size_64bit(sizeof(u64)) /* IFLA_BRPORT_HOLD_TIMER */
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 		+ nla_total_size(sizeof(u8))	/* IFLA_BRPORT_MULTICAST_ROUTER */
+		+ nla_total_size(sizeof(u32))	/* IFLA_BRPORT_MCAST_N_GROUPS */
+		+ nla_total_size(sizeof(u32))	/* IFLA_BRPORT_MCAST_MAX_GROUPS */
 #endif
 		+ nla_total_size(sizeof(u16))	/* IFLA_BRPORT_GROUP_FWD_MASK */
 		+ nla_total_size(sizeof(u8))	/* IFLA_BRPORT_MRP_RING_OPEN */

@@ -298,7 +300,11 @@ static int br_port_fill_attrs(struct sk_buff *skb,
 	    nla_put_u32(skb, IFLA_BRPORT_MCAST_EHT_HOSTS_LIMIT,
 			p->multicast_eht_hosts_limit) ||
 	    nla_put_u32(skb, IFLA_BRPORT_MCAST_EHT_HOSTS_CNT,
-			p->multicast_eht_hosts_cnt))
+			p->multicast_eht_hosts_cnt) ||
+	    nla_put_u32(skb, IFLA_BRPORT_MCAST_N_GROUPS,
+			br_multicast_port_ngroups_get(p)) ||
+	    nla_put_u32(skb, IFLA_BRPORT_MCAST_MAX_GROUPS,
+			br_multicast_port_ngroups_get_max(p)))
 		return -EMSGSIZE;
 #endif
 

@@ -883,6 +889,8 @@ static const struct nla_policy br_port_policy[IFLA_BRPORT_MAX + 1] = {
 	[IFLA_BRPORT_MAB] = { .type = NLA_U8 },
 	[IFLA_BRPORT_BACKUP_PORT] = { .type = NLA_U32 },
 	[IFLA_BRPORT_MCAST_EHT_HOSTS_LIMIT] = { .type = NLA_U32 },
+	[IFLA_BRPORT_MCAST_N_GROUPS] = { .type = NLA_REJECT },
+	[IFLA_BRPORT_MCAST_MAX_GROUPS] = { .type = NLA_U32 },
 };
 
 /* Change the state of the port and notify spanning tree */

@@ -1017,6 +1025,13 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[],
 		if (err)
 			return err;
 	}
+
+	if (tb[IFLA_BRPORT_MCAST_MAX_GROUPS]) {
+		u32 max_groups;
+
+		max_groups = nla_get_u32(tb[IFLA_BRPORT_MCAST_MAX_GROUPS]);
+		br_multicast_port_ngroups_set_max(p, max_groups);
+	}
 #endif
 
 	if (tb[IFLA_BRPORT_GROUP_FWD_MASK]) {

net/bridge/br_private.h +14 -1

index 49f411a0a1f1..98f3836efb84 100644
@@ -978,6 +978,18 @@ void br_multicast_uninit_stats(struct net_bridge *br);
 void br_multicast_get_stats(const struct net_bridge *br,
 			    const struct net_bridge_port *p,
 			    struct br_mcast_stats *dest);
+u32 br_multicast_port_ngroups_get(const struct net_bridge_port *port);
+int br_multicast_vlan_ngroups_get(struct net_bridge *br,
+				  const struct net_bridge_vlan *v,
+				  u32 *n);
+void br_multicast_port_ngroups_set_max(struct net_bridge_port *port, u32 max);
+int br_multicast_vlan_ngroups_set_max(struct net_bridge *br,
+				      struct net_bridge_vlan *v, u32 max,
+				      struct netlink_ext_ack *extack);
+u32 br_multicast_port_ngroups_get_max(const struct net_bridge_port *port);
+int br_multicast_vlan_ngroups_get_max(struct net_bridge *br,
+				      const struct net_bridge_vlan *v,
+				      u32 *max);
 void br_mdb_init(void);
 void br_mdb_uninit(void);
 void br_multicast_host_join(const struct net_bridge_mcast *brmctx,

@@ -1761,7 +1773,8 @@ static inline u16 br_vlan_flags(const struct net_bridge_vlan *v, u16 pvid)
 #ifdef CONFIG_BRIDGE_VLAN_FILTERING
 bool br_vlan_opts_eq_range(const struct net_bridge_vlan *v_curr,
 			   const struct net_bridge_vlan *range_end);
-bool br_vlan_opts_fill(struct sk_buff *skb, const struct net_bridge_vlan *v);
+bool br_vlan_opts_fill(struct sk_buff *skb, const struct net_bridge_vlan *v,
+		       const struct net_bridge_port *p);
 size_t br_vlan_opts_nl_size(void);
 int br_vlan_process_options(const struct net_bridge *br,
 			    const struct net_bridge_port *p,

net/bridge/br_vlan.c +7 -4

index bc75fa1e4666..8a3dbc09ba38 100644
@@ -1816,6 +1816,7 @@ static bool br_vlan_stats_fill(struct sk_buff *skb,
 /* v_opts is used to dump the options which must be equal in the whole range */
 static bool br_vlan_fill_vids(struct sk_buff *skb, u16 vid, u16 vid_range,
 			      const struct net_bridge_vlan *v_opts,
+			      const struct net_bridge_port *p,
 			      u16 flags,
 			      bool dump_stats)
 {

@@ -1842,7 +1843,7 @@ static bool br_vlan_fill_vids(struct sk_buff *skb, u16 vid, u16 vid_range,
 		goto out_err;
 
 	if (v_opts) {
-		if (!br_vlan_opts_fill(skb, v_opts))
+		if (!br_vlan_opts_fill(skb, v_opts, p))
 			goto out_err;
 
 		if (dump_stats && !br_vlan_stats_fill(skb, v_opts))

@@ -1925,7 +1926,7 @@ void br_vlan_notify(const struct net_bridge *br,
 		goto out_kfree;
 	}
 
-	if (!br_vlan_fill_vids(skb, vid, vid_range, v, flags, false))
+	if (!br_vlan_fill_vids(skb, vid, vid_range, v, p, flags, false))
 		goto out_err;
 
 	nlmsg_end(skb, nlh);

@@ -2030,7 +2031,7 @@ static int br_vlan_dump_dev(const struct net_device *dev,
 
 			if (!br_vlan_fill_vids(skb, range_start->vid,
 					       range_end->vid, range_start,
-					       vlan_flags, dump_stats)) {
+					       p, vlan_flags, dump_stats)) {
 				err = -EMSGSIZE;
 				break;
 			}

@@ -2056,7 +2057,7 @@ static int br_vlan_dump_dev(const struct net_device *dev,
 		else if (!dump_global &&
 			 !br_vlan_fill_vids(skb, range_start->vid,
 					    range_end->vid, range_start,
-					    br_vlan_flags(range_start, pvid),
+					    p, br_vlan_flags(range_start, pvid),
 					    dump_stats))
 			err = -EMSGSIZE;
 	}

@@ -2131,6 +2132,8 @@ static const struct nla_policy br_vlan_db_policy[BRIDGE_VLANDB_ENTRY_MAX + 1] =
 	[BRIDGE_VLANDB_ENTRY_STATE]	= { .type = NLA_U8 },
 	[BRIDGE_VLANDB_ENTRY_TUNNEL_INFO] = { .type = NLA_NESTED },
 	[BRIDGE_VLANDB_ENTRY_MCAST_ROUTER]	= { .type = NLA_U8 },
+	[BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS]	= { .type = NLA_REJECT },
+	[BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS]	= { .type = NLA_U32 },
 };
 
 static int br_vlan_rtm_process_one(struct net_device *dev,

net/bridge/br_vlan_options.c +32 -1

index a2724d03278c..43d8f11ce79c 100644
@@ -48,7 +48,8 @@ bool br_vlan_opts_eq_range(const struct net_bridge_vlan *v_curr,
 	       curr_mc_rtr == range_mc_rtr;
 }
 
-bool br_vlan_opts_fill(struct sk_buff *skb, const struct net_bridge_vlan *v)
+bool br_vlan_opts_fill(struct sk_buff *skb, const struct net_bridge_vlan *v,
+		       const struct net_bridge_port *p)
 {
 	if (nla_put_u8(skb, BRIDGE_VLANDB_ENTRY_STATE, br_vlan_get_state(v)) ||
 	    !__vlan_tun_put(skb, v))

@@ -58,6 +59,20 @@ bool br_vlan_opts_fill(struct sk_buff *skb, const struct net_bridge_vlan *v)
 	if (nla_put_u8(skb, BRIDGE_VLANDB_ENTRY_MCAST_ROUTER,
 		       br_vlan_multicast_router(v)))
 		return false;
+	if (p && !br_multicast_port_ctx_vlan_disabled(&v->port_mcast_ctx)) {
+		u32 mdb_max_entries;
+		u32 mdb_n_entries;
+
+		if (br_multicast_vlan_ngroups_get(p->br, v, &mdb_n_entries) ||
+		    nla_put_u32(skb, BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS,
+				mdb_n_entries))
+			return false;
+		if (br_multicast_vlan_ngroups_get_max(p->br, v,
+						      &mdb_max_entries) ||
+		    nla_put_u32(skb, BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS,
+				mdb_max_entries))
+			return false;
+	}
 #endif
 
 	return true;

@@ -70,6 +85,8 @@ size_t br_vlan_opts_nl_size(void)
 	       + nla_total_size(sizeof(u32)) /* BRIDGE_VLANDB_TINFO_ID */
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 	       + nla_total_size(sizeof(u8)) /* BRIDGE_VLANDB_ENTRY_MCAST_ROUTER */
+	       + nla_total_size(sizeof(u32)) /* BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS */
+	       + nla_total_size(sizeof(u32)) /* BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS */
 #endif
 	       + 0;
 }

@@ -212,6 +229,20 @@ static int br_vlan_process_one_opts(const struct net_bridge *br,
 			return err;
 		*changed = true;
 	}
+	if (tb[BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS]) {
+		u32 val;
+
+		if (!p) {
+			NL_SET_ERR_MSG_MOD(extack, "Can't set mcast_max_groups for non-port vlans");
+			return -EINVAL;
+		}
+
+		val = nla_get_u32(tb[BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS]);
+		err = br_multicast_vlan_ngroups_set_max(p->br, v, val, extack);
+		if (err)
+			return err;
+		*changed = true;
+	}
 #endif
 
 	return 0;

net/core/rtnetlink.c +1 -1

index 64289bc98887..e786255a8360 100644
@@ -58,7 +58,7 @@
 #include "dev.h"
 
 #define RTNL_MAX_TYPE		50
-#define RTNL_SLAVE_MAX_TYPE	40
+#define RTNL_SLAVE_MAX_TYPE	42
 
 struct rtnl_link {
 	rtnl_doit_func		doit;

Quoted 99 lines · Petr Machata

The previous patch added accounting for number of MDB entries per port and per port-VLAN, and the logic to verify that these values stay within configured bounds. However it didn't provide means to actually configure those bounds or read the occupancy. This patch does that.

Two new netlink attributes are added for the MDB occupancy:
IFLA_BRPORT_MCAST_N_GROUPS for the per-port occupancy and BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS for the per-port-VLAN occupancy. And another two for the maximum number of MDB entries:
IFLA_BRPORT_MCAST_MAX_GROUPS for the per-port maximum, and BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS for the per-port-VLAN one.

Note that the two new IFLA_BRPORT_ attributes prompt bumping of RTNL_SLAVE_MAX_TYPE to size the slave attribute tables large enough.

The new attributes are used like this:

 # ip link add name br up type bridge vlan_filtering 1 mcast_snooping 1 \
                                      mcast_vlan_snooping 1 mcast_querier 1
 # ip link set dev v1 master br
 # bridge vlan add dev v1 vid 2

 # bridge vlan set dev v1 vid 1 mcast_max_groups 1
 # bridge mdb add dev br port v1 grp 230.1.2.3 temp vid 1
 # bridge mdb add dev br port v1 grp 230.1.2.4 temp vid 1
 Error: bridge: Port-VLAN is already a member in mcast_max_groups (1) groups.

 # bridge link set dev v1 mcast_max_groups 1
 # bridge mdb add dev br port v1 grp 230.1.2.3 temp vid 2
 Error: bridge: Port is already a member in mcast_max_groups (1) groups.

 # bridge -d link show
 5: v1@v2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master br [...]
     [...] mcast_n_groups 1 mcast_max_groups 1

 # bridge -d vlan show
 port              vlan-id
 br                1 PVID Egress Untagged
                     state forwarding mcast_router 1
 v1                1 PVID Egress Untagged
                     [...] mcast_n_groups 1 mcast_max_groups 1
                   2
                     [...] mcast_n_groups 0 mcast_max_groups 0

Signed-off-by Petr Machata <[email protected]>

---

Notes:

    v2:
    - Drop locks around accesses in
      br_multicast_{port,vlan}_ngroups_{get,set_max}(),
    - Drop bounces due to max<n in
      br_multicast_{port,vlan}_ngroups_set_max().

 include/uapi/linux/if_bridge.h |  2 ++
 include/uapi/linux/if_link.h   |  2 ++
 net/bridge/br_multicast.c      | 50 ++++++++++++++++++++++++++++++++++
 net/bridge/br_netlink.c        | 17 +++++++++++-
 net/bridge/br_private.h        | 15 +++++++++-
 net/bridge/br_vlan.c           | 11 +++++---
 net/bridge/br_vlan_options.c   | 33 +++++++++++++++++++++-
 net/core/rtnetlink.c           |  2 +-
 8 files changed, 124 insertions(+), 8 deletions(-)

include/uapi/linux/if_bridge.h +2 -0

index d9de241d90f9..d60c456710b3 100644
@@ -523,6 +523,8 @@ enum {
 	BRIDGE_VLANDB_ENTRY_TUNNEL_INFO,
 	BRIDGE_VLANDB_ENTRY_STATS,
 	BRIDGE_VLANDB_ENTRY_MCAST_ROUTER,
+	BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS,
+	BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS,
 	__BRIDGE_VLANDB_ENTRY_MAX,
 };
 #define BRIDGE_VLANDB_ENTRY_MAX (__BRIDGE_VLANDB_ENTRY_MAX - 1)

include/uapi/linux/if_link.h +2 -0

index 1021a7e47a86..1bed3a72939c 100644
@@ -564,6 +564,8 @@ enum {
 	IFLA_BRPORT_MCAST_EHT_HOSTS_CNT,
 	IFLA_BRPORT_LOCKED,
 	IFLA_BRPORT_MAB,
+	IFLA_BRPORT_MCAST_N_GROUPS,
+	IFLA_BRPORT_MCAST_MAX_GROUPS,
 	__IFLA_BRPORT_MAX
 };
 #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)

net/bridge/br_multicast.c +1 -0

index e7ae339a8757..393ffc21c3e8 100644
@@ -768,6 +768,56 @@ static void br_multicast_port_ngroups_dec(struct net_bridge_port *port, u16 vid)
 	br_multicast_port_ngroups_dec_one(&port->multicast_ctx);
 }
 
+u32 br_multicast_port_ngroups_get(const struct net_bridge_port *port)

net/bridge/br_multicast.c static void br_multicast_port_ngroups_dec(struct net_bridge_port *port, u16 vid) · line 781

Quoted 10 lines

net/bridge/br_multicast.c +10 -0

+{
+	return READ_ONCE(port->multicast_ctx.mdb_n_entries);
+}
+
+int br_multicast_vlan_ngroups_get(struct net_bridge *br,
+				  const struct net_bridge_vlan *v,
+				  u32 *n)
+{
+	if (br_multicast_port_ctx_vlan_disabled(&v->port_mcast_ctx))
+		return -EINVAL;

This check seems unnecessary since the helper is used only if !br_multicast_port_ctx_vlan_disabled() below.

Quoted 12 lines

net/bridge/br_multicast.c +12 -0

+
+	*n = READ_ONCE(v->port_mcast_ctx.mdb_n_entries);
+	return 0;
+}
+
+void br_multicast_port_ngroups_set_max(struct net_bridge_port *port, u32 max)
+{
+	WRITE_ONCE(port->multicast_ctx.mdb_max_entries, max);
+}
+
+int br_multicast_vlan_ngroups_set_max(struct net_bridge *br,
+				      struct net_bridge_vlan *v, u32 max,

net/bridge/br_multicast.c static void br_multicast_port_ngroups_dec(struct net_bridge_port *port, u16 vid) · line 799

Quoted 6 lines

net/bridge/br_multicast.c +6 -0

+				      struct netlink_ext_ack *extack)
+{
+	if (br_multicast_port_ctx_vlan_disabled(&v->port_mcast_ctx)) {
+		NL_SET_ERR_MSG_MOD(extack, "Multicast snooping disabled on this VLAN");
+		return -EINVAL;
+	}

same comment about the check

Quoted 11 lines

net/bridge/br_multicast.c +10 -0

+
+	WRITE_ONCE(v->port_mcast_ctx.mdb_max_entries, max);
+	return 0;
+}
+
+u32 br_multicast_port_ngroups_get_max(const struct net_bridge_port *port)
+{
+	return READ_ONCE(port->multicast_ctx.mdb_max_entries);
+}
+

net/bridge/br_multicast.c static void br_multicast_port_ngroups_dec(struct net_bridge_port *port, u16 vid) · line 819

Quoted 10 lines

net/bridge/br_multicast.c +10 -0

+int br_multicast_vlan_ngroups_get_max(struct net_bridge *br,
+				      const struct net_bridge_vlan *v,
+				      u32 *max)
+{
+	if (br_multicast_port_ctx_vlan_disabled(&v->port_mcast_ctx))
+		return -EINVAL;
+
+	*max = READ_ONCE(v->port_mcast_ctx.mdb_max_entries);
+	return 0;
+}

So I don't think we need special flavours for vlan and port, the point of using common port_mcast_ctx for both was to unify the code as much as possible. If the reason was to add that check then we already have it below before calling that code, no? Could we instead add one helper for each action that takes pmctx pointers and works on them?

Thanks,
Nik

Quoted 221 lines

net/bridge/br_multicast.c +1 -0

+
 static void br_multicast_destroy_port_group(struct net_bridge_mcast_gc *gc)
 {
 	struct net_bridge_port_group *pg;

net/bridge/br_netlink.c +16 -1

index a6133d469885..968d0963d9a9 100644
@@ -202,6 +202,8 @@ static inline size_t br_port_info_size(void)
 		+ nla_total_size_64bit(sizeof(u64)) /* IFLA_BRPORT_HOLD_TIMER */
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 		+ nla_total_size(sizeof(u8))	/* IFLA_BRPORT_MULTICAST_ROUTER */
+		+ nla_total_size(sizeof(u32))	/* IFLA_BRPORT_MCAST_N_GROUPS */
+		+ nla_total_size(sizeof(u32))	/* IFLA_BRPORT_MCAST_MAX_GROUPS */
 #endif
 		+ nla_total_size(sizeof(u16))	/* IFLA_BRPORT_GROUP_FWD_MASK */
 		+ nla_total_size(sizeof(u8))	/* IFLA_BRPORT_MRP_RING_OPEN */

@@ -298,7 +300,11 @@ static int br_port_fill_attrs(struct sk_buff *skb,
 	    nla_put_u32(skb, IFLA_BRPORT_MCAST_EHT_HOSTS_LIMIT,
 			p->multicast_eht_hosts_limit) ||
 	    nla_put_u32(skb, IFLA_BRPORT_MCAST_EHT_HOSTS_CNT,
-			p->multicast_eht_hosts_cnt))
+			p->multicast_eht_hosts_cnt) ||
+	    nla_put_u32(skb, IFLA_BRPORT_MCAST_N_GROUPS,
+			br_multicast_port_ngroups_get(p)) ||
+	    nla_put_u32(skb, IFLA_BRPORT_MCAST_MAX_GROUPS,
+			br_multicast_port_ngroups_get_max(p)))
 		return -EMSGSIZE;
 #endif
 

@@ -883,6 +889,8 @@ static const struct nla_policy br_port_policy[IFLA_BRPORT_MAX + 1] = {
 	[IFLA_BRPORT_MAB] = { .type = NLA_U8 },
 	[IFLA_BRPORT_BACKUP_PORT] = { .type = NLA_U32 },
 	[IFLA_BRPORT_MCAST_EHT_HOSTS_LIMIT] = { .type = NLA_U32 },
+	[IFLA_BRPORT_MCAST_N_GROUPS] = { .type = NLA_REJECT },
+	[IFLA_BRPORT_MCAST_MAX_GROUPS] = { .type = NLA_U32 },
 };
 
 /* Change the state of the port and notify spanning tree */

@@ -1017,6 +1025,13 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[],
 		if (err)
 			return err;
 	}
+
+	if (tb[IFLA_BRPORT_MCAST_MAX_GROUPS]) {
+		u32 max_groups;
+
+		max_groups = nla_get_u32(tb[IFLA_BRPORT_MCAST_MAX_GROUPS]);
+		br_multicast_port_ngroups_set_max(p, max_groups);
+	}
 #endif
 
 	if (tb[IFLA_BRPORT_GROUP_FWD_MASK]) {

net/bridge/br_private.h +14 -1

index 49f411a0a1f1..98f3836efb84 100644
@@ -978,6 +978,18 @@ void br_multicast_uninit_stats(struct net_bridge *br);
 void br_multicast_get_stats(const struct net_bridge *br,
 			    const struct net_bridge_port *p,
 			    struct br_mcast_stats *dest);
+u32 br_multicast_port_ngroups_get(const struct net_bridge_port *port);
+int br_multicast_vlan_ngroups_get(struct net_bridge *br,
+				  const struct net_bridge_vlan *v,
+				  u32 *n);
+void br_multicast_port_ngroups_set_max(struct net_bridge_port *port, u32 max);
+int br_multicast_vlan_ngroups_set_max(struct net_bridge *br,
+				      struct net_bridge_vlan *v, u32 max,
+				      struct netlink_ext_ack *extack);
+u32 br_multicast_port_ngroups_get_max(const struct net_bridge_port *port);
+int br_multicast_vlan_ngroups_get_max(struct net_bridge *br,
+				      const struct net_bridge_vlan *v,
+				      u32 *max);
 void br_mdb_init(void);
 void br_mdb_uninit(void);
 void br_multicast_host_join(const struct net_bridge_mcast *brmctx,

@@ -1761,7 +1773,8 @@ static inline u16 br_vlan_flags(const struct net_bridge_vlan *v, u16 pvid)
 #ifdef CONFIG_BRIDGE_VLAN_FILTERING
 bool br_vlan_opts_eq_range(const struct net_bridge_vlan *v_curr,
 			   const struct net_bridge_vlan *range_end);
-bool br_vlan_opts_fill(struct sk_buff *skb, const struct net_bridge_vlan *v);
+bool br_vlan_opts_fill(struct sk_buff *skb, const struct net_bridge_vlan *v,
+		       const struct net_bridge_port *p);
 size_t br_vlan_opts_nl_size(void);
 int br_vlan_process_options(const struct net_bridge *br,
 			    const struct net_bridge_port *p,

net/bridge/br_vlan.c +7 -4

index bc75fa1e4666..8a3dbc09ba38 100644
@@ -1816,6 +1816,7 @@ static bool br_vlan_stats_fill(struct sk_buff *skb,
 /* v_opts is used to dump the options which must be equal in the whole range */
 static bool br_vlan_fill_vids(struct sk_buff *skb, u16 vid, u16 vid_range,
 			      const struct net_bridge_vlan *v_opts,
+			      const struct net_bridge_port *p,
 			      u16 flags,
 			      bool dump_stats)
 {

@@ -1842,7 +1843,7 @@ static bool br_vlan_fill_vids(struct sk_buff *skb, u16 vid, u16 vid_range,
 		goto out_err;
 
 	if (v_opts) {
-		if (!br_vlan_opts_fill(skb, v_opts))
+		if (!br_vlan_opts_fill(skb, v_opts, p))
 			goto out_err;
 
 		if (dump_stats && !br_vlan_stats_fill(skb, v_opts))

@@ -1925,7 +1926,7 @@ void br_vlan_notify(const struct net_bridge *br,
 		goto out_kfree;
 	}
 
-	if (!br_vlan_fill_vids(skb, vid, vid_range, v, flags, false))
+	if (!br_vlan_fill_vids(skb, vid, vid_range, v, p, flags, false))
 		goto out_err;
 
 	nlmsg_end(skb, nlh);

@@ -2030,7 +2031,7 @@ static int br_vlan_dump_dev(const struct net_device *dev,
 
 			if (!br_vlan_fill_vids(skb, range_start->vid,
 					       range_end->vid, range_start,
-					       vlan_flags, dump_stats)) {
+					       p, vlan_flags, dump_stats)) {
 				err = -EMSGSIZE;
 				break;
 			}

@@ -2056,7 +2057,7 @@ static int br_vlan_dump_dev(const struct net_device *dev,
 		else if (!dump_global &&
 			 !br_vlan_fill_vids(skb, range_start->vid,
 					    range_end->vid, range_start,
-					    br_vlan_flags(range_start, pvid),
+					    p, br_vlan_flags(range_start, pvid),
 					    dump_stats))
 			err = -EMSGSIZE;
 	}

@@ -2131,6 +2132,8 @@ static const struct nla_policy br_vlan_db_policy[BRIDGE_VLANDB_ENTRY_MAX + 1] =
 	[BRIDGE_VLANDB_ENTRY_STATE]	= { .type = NLA_U8 },
 	[BRIDGE_VLANDB_ENTRY_TUNNEL_INFO] = { .type = NLA_NESTED },
 	[BRIDGE_VLANDB_ENTRY_MCAST_ROUTER]	= { .type = NLA_U8 },
+	[BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS]	= { .type = NLA_REJECT },
+	[BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS]	= { .type = NLA_U32 },
 };
 
 static int br_vlan_rtm_process_one(struct net_device *dev,

net/bridge/br_vlan_options.c +32 -1

index a2724d03278c..43d8f11ce79c 100644
@@ -48,7 +48,8 @@ bool br_vlan_opts_eq_range(const struct net_bridge_vlan *v_curr,
 	       curr_mc_rtr == range_mc_rtr;
 }
 
-bool br_vlan_opts_fill(struct sk_buff *skb, const struct net_bridge_vlan *v)
+bool br_vlan_opts_fill(struct sk_buff *skb, const struct net_bridge_vlan *v,
+		       const struct net_bridge_port *p)
 {
 	if (nla_put_u8(skb, BRIDGE_VLANDB_ENTRY_STATE, br_vlan_get_state(v)) ||
 	    !__vlan_tun_put(skb, v))

@@ -58,6 +59,20 @@ bool br_vlan_opts_fill(struct sk_buff *skb, const struct net_bridge_vlan *v)
 	if (nla_put_u8(skb, BRIDGE_VLANDB_ENTRY_MCAST_ROUTER,
 		       br_vlan_multicast_router(v)))
 		return false;
+	if (p && !br_multicast_port_ctx_vlan_disabled(&v->port_mcast_ctx)) {
+		u32 mdb_max_entries;
+		u32 mdb_n_entries;
+
+		if (br_multicast_vlan_ngroups_get(p->br, v, &mdb_n_entries) ||
+		    nla_put_u32(skb, BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS,
+				mdb_n_entries))
+			return false;
+		if (br_multicast_vlan_ngroups_get_max(p->br, v,
+						      &mdb_max_entries) ||
+		    nla_put_u32(skb, BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS,
+				mdb_max_entries))
+			return false;
+	}
 #endif
 
 	return true;

@@ -70,6 +85,8 @@ size_t br_vlan_opts_nl_size(void)
 	       + nla_total_size(sizeof(u32)) /* BRIDGE_VLANDB_TINFO_ID */
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 	       + nla_total_size(sizeof(u8)) /* BRIDGE_VLANDB_ENTRY_MCAST_ROUTER */
+	       + nla_total_size(sizeof(u32)) /* BRIDGE_VLANDB_ENTRY_MCAST_N_GROUPS */
+	       + nla_total_size(sizeof(u32)) /* BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS */
 #endif
 	       + 0;
 }

@@ -212,6 +229,20 @@ static int br_vlan_process_one_opts(const struct net_bridge *br,
 			return err;
 		*changed = true;
 	}
+	if (tb[BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS]) {
+		u32 val;
+
+		if (!p) {
+			NL_SET_ERR_MSG_MOD(extack, "Can't set mcast_max_groups for non-port vlans");
+			return -EINVAL;
+		}
+
+		val = nla_get_u32(tb[BRIDGE_VLANDB_ENTRY_MCAST_MAX_GROUPS]);
+		err = br_multicast_vlan_ngroups_set_max(p->br, v, val, extack);
+		if (err)
+			return err;
+		*changed = true;
+	}
 #endif
 
 	return 0;

net/core/rtnetlink.c +1 -1

index 64289bc98887..e786255a8360 100644
@@ -58,7 +58,7 @@
 #include "dev.h"
 
 #define RTNL_MAX_TYPE		50
-#define RTNL_SLAVE_MAX_TYPE	40
+#define RTNL_SLAVE_MAX_TYPE	42
 
 struct rtnl_link {
 	rtnl_doit_func		doit;

Quoted 11 lines · Nikolay Aleksandrov

net/bridge/br_multicast.c static void br_multicast_port_ngroups_dec(struct net_bridge_port *port, u16 vid) · line 799

Quoted 8 lines · Petr Machata

net/bridge/br_multicast.c +8 -0

+int br_multicast_vlan_ngroups_set_max(struct net_bridge *br,
+				      struct net_bridge_vlan *v, u32 max,
+				      struct netlink_ext_ack *extack)
+{
+	if (br_multicast_port_ctx_vlan_disabled(&v->port_mcast_ctx)) {
+		NL_SET_ERR_MSG_MOD(extack, "Multicast snooping disabled on this VLAN");
+		return -EINVAL;
+	}

same comment about the check

Ok, not exactly the same. I see that for the max case this check is used, please pull it in the vlan code and just drop this helper. Both read/write will be doing the same then.

Subject: [PATCH net-next mlxsw v2 00/16] bridge: Limit number of MDB entries per port, port-vlan

Quoted 1 line · On Wed, 1 Feb 2023 18:28:33 +0100 Petr Machata wrote:

Subject: [PATCH net-next mlxsw v2 00/16] bridge: Limit number of MDB entries per port, port-vlan

What do you mean by "net-next mlxsw"?
Is there a tree called "net-next mlxsw" somewhere?