net: bridge: Add netlink knobs for number / maximum MDB entries

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 in 1 groups, and mcast_max_groups=1.

 # 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 in 1 groups, and mcast_max_groups=1.

 # 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 <petrm@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 49f411a0a1f1..cef5f6ea850c 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -978,6 +978,9 @@ 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_ngroups_get(const struct net_bridge_mcast_port *pmctx);
+void br_multicast_ngroups_set_max(struct net_bridge_mcast_port *pmctx, u32 max);
+u32 br_multicast_ngroups_get_max(const struct net_bridge_mcast_port *pmctx);
 void br_mdb_init(void);
 void br_mdb_uninit(void);
 void br_multicast_host_join(const struct net_bridge_mcast *brmctx,
@@ -1761,7 +1764,8 @@ 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,