[Patch net-next 3/3] net: bridge: Add notify on flag change netlink i/f

From: Joseph Huang
Date: Tue Mar 18 2025 - 18:45:10 EST


Add netlink interface to manipulate the mdb_notify_on_flag_change knob.

Signed-off-by: Joseph Huang <Joseph.Huang@xxxxxxxxxx>
---
include/uapi/linux/if_link.h | 14 ++++++++++++++
net/bridge/br_netlink.c | 21 +++++++++++++++++++++
2 files changed, 35 insertions(+)

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index bfe880fbbb24..8fa830599972 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -741,6 +741,19 @@ enum in6_addr_gen_mode {
* @IFLA_BR_FDB_MAX_LEARNED
* Set the number of max dynamically learned FDB entries for the current
* bridge.
+ *
+ * @IFLA_BR_MDB_NOTIFY_ON_FLAG_CHANGE
+ * Set how the bridge shall notify user space about MDB flag change via
+ * RTM_NEWMDB netlink message.
+ * The valid values are:
+ *
+ * * 0 - the bridge will not notify user space about MDB flag change
+ * * 1 - the bridge will notify user space about flag change if either
+ * MDB_PG_FLAGS_OFFLOAD or MDB_PG_FLAGS_OFFLOAD_FAILED has changed
+ * * 2 - the bridge will notify user space about flag change only if
+ * MDB_PG_FLAGS_OFFLOAD_FAILED has changed
+ *
+ * The default value is 0.
*/
enum {
IFLA_BR_UNSPEC,
@@ -793,6 +806,7 @@ enum {
IFLA_BR_MCAST_QUERIER_STATE,
IFLA_BR_FDB_N_LEARNED,
IFLA_BR_FDB_MAX_LEARNED,
+ IFLA_BR_MDB_NOTIFY_ON_FLAG_CHANGE,
__IFLA_BR_MAX,
};

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 3e0f47203f2a..e87d39b148d8 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -1270,6 +1270,7 @@ static const struct nla_policy br_policy[IFLA_BR_MAX + 1] = {
NLA_POLICY_EXACT_LEN(sizeof(struct br_boolopt_multi)),
[IFLA_BR_FDB_N_LEARNED] = { .type = NLA_REJECT },
[IFLA_BR_FDB_MAX_LEARNED] = { .type = NLA_U32 },
+ [IFLA_BR_MDB_NOTIFY_ON_FLAG_CHANGE] = { .type = NLA_U8 },
};

static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
@@ -1514,6 +1515,18 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
return err;
}
#endif
+
+#ifdef CONFIG_NET_SWITCHDEV
+ if (data[IFLA_BR_MDB_NOTIFY_ON_FLAG_CHANGE]) {
+ __u8 val;
+
+ val = nla_get_u8(data[IFLA_BR_MDB_NOTIFY_ON_FLAG_CHANGE]);
+ err = br_multicast_set_mdb_notify_on_flag_change(&br->multicast_ctx,
+ val);
+ if (err)
+ return err;
+ }
+#endif
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
if (data[IFLA_BR_NF_CALL_IPTABLES]) {
@@ -1625,6 +1638,9 @@ static size_t br_get_size(const struct net_device *brdev)
nla_total_size(sizeof(u8)) + /* IFLA_BR_MCAST_IGMP_VERSION */
nla_total_size(sizeof(u8)) + /* IFLA_BR_MCAST_MLD_VERSION */
br_multicast_querier_state_size() + /* IFLA_BR_MCAST_QUERIER_STATE */
+#ifdef CONFIG_NET_SWITCHDEV
+ nla_total_size(sizeof(u8)) + /* IFLA_BR_MDB_NOTIFY_ON_FLAG_CHANGE */
+#endif
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
nla_total_size(sizeof(u8)) + /* IFLA_BR_NF_CALL_IPTABLES */
@@ -1722,6 +1738,11 @@ static int br_fill_info(struct sk_buff *skb, const struct net_device *brdev)
if (nla_put_u8(skb, IFLA_BR_MCAST_MLD_VERSION,
br->multicast_ctx.multicast_mld_version))
return -EMSGSIZE;
+#endif
+#ifdef CONFIG_NET_SWITCHDEV
+ if (nla_put_u8(skb, IFLA_BR_MDB_NOTIFY_ON_FLAG_CHANGE,
+ br->multicast_ctx.multicast_mdb_notify_on_flag_change))
+ return -EMSGSIZE;
#endif
clockval = jiffies_to_clock_t(br->multicast_ctx.multicast_last_member_interval);
if (nla_put_u64_64bit(skb, IFLA_BR_MCAST_LAST_MEMBER_INTVL, clockval,
--
2.49.0