linux-kernel - [PATCH 7/9] net: bridge: mcast: active state, if snooping is enabled

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Message-ID: <20250829085724.24230-8-linus.luessing@c0d3.blue>
Date: Fri, 29 Aug 2025 10:53:48 +0200
From: Linus Lüssing <linus.luessing@...3.blue>
To: bridge@...ts.linux.dev
Cc: netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Nikolay Aleksandrov <razor@...ckwall.org>,
	Ido Schimmel <idosch@...dia.com>,
	Andrew Lunn <andrew+netdev@...n.ch>,
	Simon Horman <horms@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Eric Dumazet <edumazet@...gle.com>,
	"David S . Miller" <davem@...emloft.net>,
	Kuniyuki Iwashima <kuniyu@...gle.com>,
	Stanislav Fomichev <sdf@...ichev.me>,
	Xiao Liang <shaw.leon@...il.com>,
	Linus Lüssing <linus.luessing@...3.blue>
Subject: [PATCH 7/9] net: bridge: mcast: active state, if snooping is enabled

To be able to use the upcoming SWITCHDEV_ATTR_ID_BRIDGE_MC_ACTIVE
as a potential replacement for SWITCHDEV_ATTR_ID_BRIDGE_MC_DISABLED
also check and toggle the active state if multicast snooping is enabled
or disabled. So that MC_ACTIVE not only checks the querier state, but
also if multicast snooping is enabled in general.

No functional change for the fast/data path yet.

Signed-off-by: Linus Lüssing <linus.luessing@...3.blue>
---
 include/uapi/linux/if_link.h |  6 ++++--
 net/bridge/br_multicast.c    | 21 +++++++++++++++++++--
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index fcf2c42aa6c4..ef686ea17afe 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -746,12 +746,14 @@ enum in6_addr_gen_mode {
  * @IFLA_BR_MCAST_ACTIVE_V4
  *   Bridge IPv4 mcast active state, read only.
  *
- *   1 if an IGMP querier is present, 0 otherwise.
+ *   1 if *IFLA_BR_MCAST_SNOOPING* is enabled and an IGMP querier is present,
+ *   0 otherwise.
  *
  * @IFLA_BR_MCAST_ACTIVE_V6
  *   Bridge IPv6 mcast active state, read only.
  *
- *   1 if an MLD querier is present, 0 otherwise.
+ *   1 if *IFLA_BR_MCAST_SNOOPING* is enabled and an MLD querier is present,
+ *   0 otherwise.
  */
 enum {
 	IFLA_BR_UNSPEC,
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 54163c74b9a9..53720337a1e3 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1145,6 +1145,7 @@ static void br_ip6_multicast_update_active(struct net_bridge_mcast *brmctx,
  *
  * The multicast active state is set, per protocol family, if:
  *
+ * - multicast snooping is enabled
  * - an IGMP/MLD querier is present
  * - for own IPv6 MLD querier: an IPv6 address is configured on the bridge
  *
@@ -1159,6 +1160,13 @@ static void br_multicast_update_active(struct net_bridge_mcast *brmctx)
 
 	lockdep_assert_held_once(&brmctx->br->multicast_lock);
 
+	if (!br_opt_get(brmctx->br, BROPT_MULTICAST_ENABLED))
+		force_inactive = true;
+
+	if (br_opt_get(brmctx->br, BROPT_MCAST_VLAN_SNOOPING_ENABLED) &&
+	    br_multicast_ctx_vlan_disabled(brmctx))
+		force_inactive = true;
+
 	br_ip4_multicast_update_active(brmctx, force_inactive);
 	br_ip6_multicast_update_active(brmctx, force_inactive);
 }
@@ -1371,6 +1379,12 @@ static struct sk_buff *br_multicast_alloc_query(struct net_bridge_mcast *brmctx,
 	return NULL;
 }
 
+static void br_multicast_toggle_enabled(struct net_bridge *br, bool on)
+{
+	br_opt_toggle(br, BROPT_MULTICAST_ENABLED, on);
+	br_multicast_update_active(&br->multicast_ctx);
+}
+
 struct net_bridge_mdb_entry *br_multicast_new_group(struct net_bridge *br,
 						    struct br_ip *group)
 {
@@ -1384,7 +1398,7 @@ struct net_bridge_mdb_entry *br_multicast_new_group(struct net_bridge *br,
 	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);
+		br_multicast_toggle_enabled(br, false);
 		return ERR_PTR(-E2BIG);
 	}
 
@@ -4452,6 +4466,7 @@ void br_multicast_toggle_one_vlan(struct net_bridge_vlan *vlan, bool on)
 
 		spin_lock_bh(&br->multicast_lock);
 		vlan->priv_flags ^= BR_VLFLAG_MCAST_ENABLED;
+		br_multicast_update_active(&vlan->br_mcast_ctx);
 		spin_unlock_bh(&br->multicast_lock);
 
 		if (on)
@@ -4472,6 +4487,7 @@ void br_multicast_toggle_one_vlan(struct net_bridge_vlan *vlan, bool on)
 			__br_multicast_enable_port_ctx(&vlan->port_mcast_ctx);
 		else
 			__br_multicast_disable_port_ctx(&vlan->port_mcast_ctx);
+		br_multicast_update_active(brmctx);
 		spin_unlock_bh(&br->multicast_lock);
 	}
 }
@@ -4792,7 +4808,8 @@ int br_multicast_toggle(struct net_bridge *br, unsigned long val,
 	if (err)
 		goto unlock;
 
-	br_opt_toggle(br, BROPT_MULTICAST_ENABLED, !!val);
+	br_multicast_toggle_enabled(br, !!val);
+
 	if (!br_opt_get(br, BROPT_MULTICAST_ENABLED)) {
 		change_snoopers = true;
 		goto unlock;
-- 
2.50.1