bridge: Add port-level netlink handling for neigh_forward_grat

Add netlink handlers for the port-level neigh_forward_grat option via
IFLA_BRPORT_NEIGH_FORWARD_GRAT attribute.

The default value of OFF preserves existing behavior, i.e. gratuitous ARP
and unsolicited NA are suppressed when neigh_suppress is enabled. Users can
explicitly set it to ON to allow these packets through.

Example for enabling control via 'bridge link' command:
 # bridge link set dev eth0 neigh_suppress on
 # bridge link set dev eth0 neigh_forward_grat on

Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260511065936.4173106-5-danieller@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 6fd5386a1d646542c184702e13cc2e6c8ee1820d..898326c201ef99a1dafda820bfbfe3d428ae2bd3 100644 (file)
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -190,6 +190,7 @@ static inline size_t br_port_info_size(void)
                + nla_total_size(1)     /* IFLA_BRPORT_LOCKED */
                + nla_total_size(1)     /* IFLA_BRPORT_MAB */
                + nla_total_size(1)     /* IFLA_BRPORT_NEIGH_VLAN_SUPPRESS */
+               + nla_total_size(1)     /* IFLA_BRPORT_NEIGH_FORWARD_GRAT */
                + nla_total_size(sizeof(struct ifla_bridge_id)) /* IFLA_BRPORT_ROOT_ID */
                + nla_total_size(sizeof(struct ifla_bridge_id)) /* IFLA_BRPORT_BRIDGE_ID */
                + nla_total_size(sizeof(u16))   /* IFLA_BRPORT_DESIGNATED_PORT */
@@ -282,7 +283,9 @@ static int br_port_fill_attrs(struct sk_buff *skb,
            nla_put_u8(skb, IFLA_BRPORT_LOCKED, !!(p->flags & BR_PORT_LOCKED)) ||
            nla_put_u8(skb, IFLA_BRPORT_MAB, !!(p->flags & BR_PORT_MAB)) ||
            nla_put_u8(skb, IFLA_BRPORT_NEIGH_VLAN_SUPPRESS,
-                      !!(p->flags & BR_NEIGH_VLAN_SUPPRESS)))
+                      !!(p->flags & BR_NEIGH_VLAN_SUPPRESS)) ||
+           nla_put_u8(skb, IFLA_BRPORT_NEIGH_FORWARD_GRAT,
+                      !!(p->flags & BR_NEIGH_FORWARD_GRAT)))
                return -EMSGSIZE;
 
        timerval = br_timer_value(&p->message_age_timer);
@@ -902,6 +905,7 @@ static const struct nla_policy br_port_policy[IFLA_BRPORT_MAX + 1] = {
        [IFLA_BRPORT_MCAST_MAX_GROUPS] = { .type = NLA_U32 },
        [IFLA_BRPORT_NEIGH_VLAN_SUPPRESS] = NLA_POLICY_MAX(NLA_U8, 1),
        [IFLA_BRPORT_BACKUP_NHID] = { .type = NLA_U32 },
+       [IFLA_BRPORT_NEIGH_FORWARD_GRAT] = NLA_POLICY_MAX(NLA_U8, 1),
 };
 
 /* Change the state of the port and notify spanning tree */
@@ -970,6 +974,8 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[],
        br_set_port_flag(p, tb, IFLA_BRPORT_MAB, BR_PORT_MAB);
        br_set_port_flag(p, tb, IFLA_BRPORT_NEIGH_VLAN_SUPPRESS,
                         BR_NEIGH_VLAN_SUPPRESS);
+       br_set_port_flag(p, tb, IFLA_BRPORT_NEIGH_FORWARD_GRAT,
+                        BR_NEIGH_FORWARD_GRAT);
 
        if ((p->flags & BR_PORT_MAB) &&
            (!(p->flags & BR_PORT_LOCKED) || !(p->flags & BR_LEARNING))) {