Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 777 insertions, 0 deletions

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
new file mode 100644
index 000000000..0989074f3
--- /dev/null
+++ b/net/bridge/br_if.c
@@ -0,0 +1,777 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Userspace interface
+ *	Linux ethernet bridge
+ *
+ *	Authors:
+ *	Lennert Buytenhek		<buytenh@gnu.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/netpoll.h>
+#include <linux/ethtool.h>
+#include <linux/if_arp.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rtnetlink.h>
+#include <linux/if_ether.h>
+#include <linux/slab.h>
+#include <net/dsa.h>
+#include <net/sock.h>
+#include <linux/if_vlan.h>
+#include <net/switchdev.h>
+#include <net/net_namespace.h>
+
+#include "br_private.h"
+
+/*
+ * Determine initial path cost based on speed.
+ * using recommendations from 802.1d standard
+ *
+ * Since driver might sleep need to not be holding any locks.
+ */
+static int port_cost(struct net_device *dev)
+{
+	struct ethtool_link_ksettings ecmd;
+
+	if (!__ethtool_get_link_ksettings(dev, &ecmd)) {
+		switch (ecmd.base.speed) {
+		case SPEED_10000:
+			return 2;
+		case SPEED_5000:
+			return 3;
+		case SPEED_2500:
+			return 4;
+		case SPEED_1000:
+			return 5;
+		case SPEED_100:
+			return 19;
+		case SPEED_10:
+			return 100;
+		case SPEED_UNKNOWN:
+			return 100;
+		default:
+			if (ecmd.base.speed > SPEED_10000)
+				return 1;
+		}
+	}
+
+	/* Old silly heuristics based on name */
+	if (!strncmp(dev->name, "lec", 3))
+		return 7;
+
+	if (!strncmp(dev->name, "plip", 4))
+		return 2500;
+
+	return 100;	/* assume old 10Mbps */
+}
+
+
+/* Check for port carrier transitions. */
+void br_port_carrier_check(struct net_bridge_port *p, bool *notified)
+{
+	struct net_device *dev = p->dev;
+	struct net_bridge *br = p->br;
+
+	if (!(p->flags & BR_ADMIN_COST) &&
+	    netif_running(dev) && netif_oper_up(dev))
+		p->path_cost = port_cost(dev);
+
+	*notified = false;
+	if (!netif_running(br->dev))
+		return;
+
+	spin_lock_bh(&br->lock);
+	if (netif_running(dev) && netif_oper_up(dev)) {
+		if (p->state == BR_STATE_DISABLED) {
+			br_stp_enable_port(p);
+			*notified = true;
+		}
+	} else {
+		if (p->state != BR_STATE_DISABLED) {
+			br_stp_disable_port(p);
+			*notified = true;
+		}
+	}
+	spin_unlock_bh(&br->lock);
+}
+
+static void br_port_set_promisc(struct net_bridge_port *p)
+{
+	int err = 0;
+
+	if (br_promisc_port(p))
+		return;
+
+	err = dev_set_promiscuity(p->dev, 1);
+	if (err)
+		return;
+
+	br_fdb_unsync_static(p->br, p);
+	p->flags |= BR_PROMISC;
+}
+
+static void br_port_clear_promisc(struct net_bridge_port *p)
+{
+	int err;
+
+	/* Check if the port is already non-promisc or if it doesn't
+	 * support UNICAST filtering.  Without unicast filtering support
+	 * we'll end up re-enabling promisc mode anyway, so just check for
+	 * it here.
+	 */
+	if (!br_promisc_port(p) || !(p->dev->priv_flags & IFF_UNICAST_FLT))
+		return;
+
+	/* Since we'll be clearing the promisc mode, program the port
+	 * first so that we don't have interruption in traffic.
+	 */
+	err = br_fdb_sync_static(p->br, p);
+	if (err)
+		return;
+
+	dev_set_promiscuity(p->dev, -1);
+	p->flags &= ~BR_PROMISC;
+}
+
+/* When a port is added or removed or when certain port flags
+ * change, this function is called to automatically manage
+ * promiscuity setting of all the bridge ports.  We are always called
+ * under RTNL so can skip using rcu primitives.
+ */
+void br_manage_promisc(struct net_bridge *br)
+{
+	struct net_bridge_port *p;
+	bool set_all = false;
+
+	/* If vlan filtering is disabled or bridge interface is placed
+	 * into promiscuous mode, place all ports in promiscuous mode.
+	 */
+	if ((br->dev->flags & IFF_PROMISC) || !br_vlan_enabled(br->dev))
+		set_all = true;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		if (set_all) {
+			br_port_set_promisc(p);
+		} else {
+			/* If the number of auto-ports is <= 1, then all other
+			 * ports will have their output configuration
+			 * statically specified through fdbs.  Since ingress
+			 * on the auto-port becomes forwarding/egress to other
+			 * ports and egress configuration is statically known,
+			 * we can say that ingress configuration of the
+			 * auto-port is also statically known.
+			 * This lets us disable promiscuous mode and write
+			 * this config to hw.
+			 */
+			if ((p->dev->priv_flags & IFF_UNICAST_FLT) &&
+			    (br->auto_cnt == 0 ||
+			     (br->auto_cnt == 1 && br_auto_port(p))))
+				br_port_clear_promisc(p);
+			else
+				br_port_set_promisc(p);
+		}
+	}
+}
+
+int nbp_backup_change(struct net_bridge_port *p,
+		      struct net_device *backup_dev)
+{
+	struct net_bridge_port *old_backup = rtnl_dereference(p->backup_port);
+	struct net_bridge_port *backup_p = NULL;
+
+	ASSERT_RTNL();
+
+	if (backup_dev) {
+		if (!netif_is_bridge_port(backup_dev))
+			return -ENOENT;
+
+		backup_p = br_port_get_rtnl(backup_dev);
+		if (backup_p->br != p->br)
+			return -EINVAL;
+	}
+
+	if (p == backup_p)
+		return -EINVAL;
+
+	if (old_backup == backup_p)
+		return 0;
+
+	/* if the backup link is already set, clear it */
+	if (old_backup)
+		old_backup->backup_redirected_cnt--;
+
+	if (backup_p)
+		backup_p->backup_redirected_cnt++;
+	rcu_assign_pointer(p->backup_port, backup_p);
+
+	return 0;
+}
+
+static void nbp_backup_clear(struct net_bridge_port *p)
+{
+	nbp_backup_change(p, NULL);
+	if (p->backup_redirected_cnt) {
+		struct net_bridge_port *cur_p;
+
+		list_for_each_entry(cur_p, &p->br->port_list, list) {
+			struct net_bridge_port *backup_p;
+
+			backup_p = rtnl_dereference(cur_p->backup_port);
+			if (backup_p == p)
+				nbp_backup_change(cur_p, NULL);
+		}
+	}
+
+	WARN_ON(rcu_access_pointer(p->backup_port) || p->backup_redirected_cnt);
+}
+
+static void nbp_update_port_count(struct net_bridge *br)
+{
+	struct net_bridge_port *p;
+	u32 cnt = 0;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		if (br_auto_port(p))
+			cnt++;
+	}
+	if (br->auto_cnt != cnt) {
+		br->auto_cnt = cnt;
+		br_manage_promisc(br);
+	}
+}
+
+static void nbp_delete_promisc(struct net_bridge_port *p)
+{
+	/* If port is currently promiscuous, unset promiscuity.
+	 * Otherwise, it is a static port so remove all addresses
+	 * from it.
+	 */
+	dev_set_allmulti(p->dev, -1);
+	if (br_promisc_port(p))
+		dev_set_promiscuity(p->dev, -1);
+	else
+		br_fdb_unsync_static(p->br, p);
+}
+
+static void release_nbp(struct kobject *kobj)
+{
+	struct net_bridge_port *p
+		= container_of(kobj, struct net_bridge_port, kobj);
+	kfree(p);
+}
+
+static void brport_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
+{
+	struct net_bridge_port *p = kobj_to_brport(kobj);
+
+	net_ns_get_ownership(dev_net(p->dev), uid, gid);
+}
+
+static struct kobj_type brport_ktype = {
+#ifdef CONFIG_SYSFS
+	.sysfs_ops = &brport_sysfs_ops,
+#endif
+	.release = release_nbp,
+	.get_ownership = brport_get_ownership,
+};
+
+static void destroy_nbp(struct net_bridge_port *p)
+{
+	struct net_device *dev = p->dev;
+
+	p->br = NULL;
+	p->dev = NULL;
+	netdev_put(dev, &p->dev_tracker);
+
+	kobject_put(&p->kobj);
+}
+
+static void destroy_nbp_rcu(struct rcu_head *head)
+{
+	struct net_bridge_port *p =
+			container_of(head, struct net_bridge_port, rcu);
+	destroy_nbp(p);
+}
+
+static unsigned get_max_headroom(struct net_bridge *br)
+{
+	unsigned max_headroom = 0;
+	struct net_bridge_port *p;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		unsigned dev_headroom = netdev_get_fwd_headroom(p->dev);
+
+		if (dev_headroom > max_headroom)
+			max_headroom = dev_headroom;
+	}
+
+	return max_headroom;
+}
+
+static void update_headroom(struct net_bridge *br, int new_hr)
+{
+	struct net_bridge_port *p;
+
+	list_for_each_entry(p, &br->port_list, list)
+		netdev_set_rx_headroom(p->dev, new_hr);
+
+	br->dev->needed_headroom = new_hr;
+}
+
+/* Delete port(interface) from bridge is done in two steps.
+ * via RCU. First step, marks device as down. That deletes
+ * all the timers and stops new packets from flowing through.
+ *
+ * Final cleanup doesn't occur until after all CPU's finished
+ * processing packets.
+ *
+ * Protected from multiple admin operations by RTNL mutex
+ */
+static void del_nbp(struct net_bridge_port *p)
+{
+	struct net_bridge *br = p->br;
+	struct net_device *dev = p->dev;
+
+	sysfs_remove_link(br->ifobj, p->dev->name);
+
+	nbp_delete_promisc(p);
+
+	spin_lock_bh(&br->lock);
+	br_stp_disable_port(p);
+	spin_unlock_bh(&br->lock);
+
+	br_mrp_port_del(br, p);
+	br_cfm_port_del(br, p);
+
+	br_ifinfo_notify(RTM_DELLINK, NULL, p);
+
+	list_del_rcu(&p->list);
+	if (netdev_get_fwd_headroom(dev) == br->dev->needed_headroom)
+		update_headroom(br, get_max_headroom(br));
+	netdev_reset_rx_headroom(dev);
+
+	nbp_vlan_flush(p);
+	br_fdb_delete_by_port(br, p, 0, 1);
+	switchdev_deferred_process();
+	nbp_backup_clear(p);
+
+	nbp_update_port_count(br);
+
+	netdev_upper_dev_unlink(dev, br->dev);
+
+	dev->priv_flags &= ~IFF_BRIDGE_PORT;
+
+	netdev_rx_handler_unregister(dev);
+
+	br_multicast_del_port(p);
+
+	kobject_uevent(&p->kobj, KOBJ_REMOVE);
+	kobject_del(&p->kobj);
+
+	br_netpoll_disable(p);
+
+	call_rcu(&p->rcu, destroy_nbp_rcu);
+}
+
+/* Delete bridge device */
+void br_dev_delete(struct net_device *dev, struct list_head *head)
+{
+	struct net_bridge *br = netdev_priv(dev);
+	struct net_bridge_port *p, *n;
+
+	list_for_each_entry_safe(p, n, &br->port_list, list) {
+		del_nbp(p);
+	}
+
+	br_recalculate_neigh_suppress_enabled(br);
+
+	br_fdb_delete_by_port(br, NULL, 0, 1);
+
+	cancel_delayed_work_sync(&br->gc_work);
+
+	br_sysfs_delbr(br->dev);
+	unregister_netdevice_queue(br->dev, head);
+}
+
+/* find an available port number */
+static int find_portno(struct net_bridge *br)
+{
+	int index;
+	struct net_bridge_port *p;
+	unsigned long *inuse;
+
+	inuse = bitmap_zalloc(BR_MAX_PORTS, GFP_KERNEL);
+	if (!inuse)
+		return -ENOMEM;
+
+	__set_bit(0, inuse);	/* zero is reserved */
+	list_for_each_entry(p, &br->port_list, list)
+		__set_bit(p->port_no, inuse);
+
+	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
+	bitmap_free(inuse);
+
+	return (index >= BR_MAX_PORTS) ? -EXFULL : index;
+}
+
+/* called with RTNL but without bridge lock */
+static struct net_bridge_port *new_nbp(struct net_bridge *br,
+				       struct net_device *dev)
+{
+	struct net_bridge_port *p;
+	int index, err;
+
+	index = find_portno(br);
+	if (index < 0)
+		return ERR_PTR(index);
+
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	if (p == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	p->br = br;
+	netdev_hold(dev, &p->dev_tracker, GFP_KERNEL);
+	p->dev = dev;
+	p->path_cost = port_cost(dev);
+	p->priority = 0x8000 >> BR_PORT_BITS;
+	p->port_no = index;
+	p->flags = BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD | BR_BCAST_FLOOD;
+	br_init_port(p);
+	br_set_state(p, BR_STATE_DISABLED);
+	br_stp_port_timer_init(p);
+	err = br_multicast_add_port(p);
+	if (err) {
+		netdev_put(dev, &p->dev_tracker);
+		kfree(p);
+		p = ERR_PTR(err);
+	}
+
+	return p;
+}
+
+int br_add_bridge(struct net *net, const char *name)
+{
+	struct net_device *dev;
+	int res;
+
+	dev = alloc_netdev(sizeof(struct net_bridge), name, NET_NAME_UNKNOWN,
+			   br_dev_setup);
+
+	if (!dev)
+		return -ENOMEM;
+
+	dev_net_set(dev, net);
+	dev->rtnl_link_ops = &br_link_ops;
+
+	res = register_netdevice(dev);
+	if (res)
+		free_netdev(dev);
+	return res;
+}
+
+int br_del_bridge(struct net *net, const char *name)
+{
+	struct net_device *dev;
+	int ret = 0;
+
+	dev = __dev_get_by_name(net, name);
+	if (dev == NULL)
+		ret =  -ENXIO; 	/* Could not find device */
+
+	else if (!netif_is_bridge_master(dev)) {
+		/* Attempt to delete non bridge device! */
+		ret = -EPERM;
+	}
+
+	else if (dev->flags & IFF_UP) {
+		/* Not shutdown yet. */
+		ret = -EBUSY;
+	}
+
+	else
+		br_dev_delete(dev, NULL);
+
+	return ret;
+}
+
+/* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
+static int br_mtu_min(const struct net_bridge *br)
+{
+	const struct net_bridge_port *p;
+	int ret_mtu = 0;
+
+	list_for_each_entry(p, &br->port_list, list)
+		if (!ret_mtu || ret_mtu > p->dev->mtu)
+			ret_mtu = p->dev->mtu;
+
+	return ret_mtu ? ret_mtu : ETH_DATA_LEN;
+}
+
+void br_mtu_auto_adjust(struct net_bridge *br)
+{
+	ASSERT_RTNL();
+
+	/* if the bridge MTU was manually configured don't mess with it */
+	if (br_opt_get(br, BROPT_MTU_SET_BY_USER))
+		return;
+
+	/* change to the minimum MTU and clear the flag which was set by
+	 * the bridge ndo_change_mtu callback
+	 */
+	dev_set_mtu(br->dev, br_mtu_min(br));
+	br_opt_toggle(br, BROPT_MTU_SET_BY_USER, false);
+}
+
+static void br_set_gso_limits(struct net_bridge *br)
+{
+	unsigned int tso_max_size = TSO_MAX_SIZE;
+	const struct net_bridge_port *p;
+	u16 tso_max_segs = TSO_MAX_SEGS;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		tso_max_size = min(tso_max_size, p->dev->tso_max_size);
+		tso_max_segs = min(tso_max_segs, p->dev->tso_max_segs);
+	}
+	netif_set_tso_max_size(br->dev, tso_max_size);
+	netif_set_tso_max_segs(br->dev, tso_max_segs);
+}
+
+/*
+ * Recomputes features using slave's features
+ */
+netdev_features_t br_features_recompute(struct net_bridge *br,
+	netdev_features_t features)
+{
+	struct net_bridge_port *p;
+	netdev_features_t mask;
+
+	if (list_empty(&br->port_list))
+		return features;
+
+	mask = features;
+	features &= ~NETIF_F_ONE_FOR_ALL;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		features = netdev_increment_features(features,
+						     p->dev->features, mask);
+	}
+	features = netdev_add_tso_features(features, mask);
+
+	return features;
+}
+
+/* called with RTNL */
+int br_add_if(struct net_bridge *br, struct net_device *dev,
+	      struct netlink_ext_ack *extack)
+{
+	struct net_bridge_port *p;
+	int err = 0;
+	unsigned br_hr, dev_hr;
+	bool changed_addr, fdb_synced = false;
+
+	/* Don't allow bridging non-ethernet like devices. */
+	if ((dev->flags & IFF_LOOPBACK) ||
+	    dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
+	    !is_valid_ether_addr(dev->dev_addr))
+		return -EINVAL;
+
+	/* No bridging of bridges */
+	if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit) {
+		NL_SET_ERR_MSG(extack,
+			       "Can not enslave a bridge to a bridge");
+		return -ELOOP;
+	}
+
+	/* Device has master upper dev */
+	if (netdev_master_upper_dev_get(dev))
+		return -EBUSY;
+
+	/* No bridging devices that dislike that (e.g. wireless) */
+	if (dev->priv_flags & IFF_DONT_BRIDGE) {
+		NL_SET_ERR_MSG(extack,
+			       "Device does not allow enslaving to a bridge");
+		return -EOPNOTSUPP;
+	}
+
+	p = new_nbp(br, dev);
+	if (IS_ERR(p))
+		return PTR_ERR(p);
+
+	call_netdevice_notifiers(NETDEV_JOIN, dev);
+
+	err = dev_set_allmulti(dev, 1);
+	if (err) {
+		br_multicast_del_port(p);
+		netdev_put(dev, &p->dev_tracker);
+		kfree(p);	/* kobject not yet init'd, manually free */
+		goto err1;
+	}
+
+	err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
+				   SYSFS_BRIDGE_PORT_ATTR);
+	if (err)
+		goto err2;
+
+	err = br_sysfs_addif(p);
+	if (err)
+		goto err2;
+
+	err = br_netpoll_enable(p);
+	if (err)
+		goto err3;
+
+	err = netdev_rx_handler_register(dev, br_get_rx_handler(dev), p);
+	if (err)
+		goto err4;
+
+	dev->priv_flags |= IFF_BRIDGE_PORT;
+
+	err = netdev_master_upper_dev_link(dev, br->dev, NULL, NULL, extack);
+	if (err)
+		goto err5;
+
+	dev_disable_lro(dev);
+
+	list_add_rcu(&p->list, &br->port_list);
+
+	nbp_update_port_count(br);
+	if (!br_promisc_port(p) && (p->dev->priv_flags & IFF_UNICAST_FLT)) {
+		/* When updating the port count we also update all ports'
+		 * promiscuous mode.
+		 * A port leaving promiscuous mode normally gets the bridge's
+		 * fdb synced to the unicast filter (if supported), however,
+		 * `br_port_clear_promisc` does not distinguish between
+		 * non-promiscuous ports and *new* ports, so we need to
+		 * sync explicitly here.
+		 */
+		fdb_synced = br_fdb_sync_static(br, p) == 0;
+		if (!fdb_synced)
+			netdev_err(dev, "failed to sync bridge static fdb addresses to this port\n");
+	}
+
+	netdev_update_features(br->dev);
+
+	br_hr = br->dev->needed_headroom;
+	dev_hr = netdev_get_fwd_headroom(dev);
+	if (br_hr < dev_hr)
+		update_headroom(br, dev_hr);
+	else
+		netdev_set_rx_headroom(dev, br_hr);
+
+	if (br_fdb_add_local(br, p, dev->dev_addr, 0))
+		netdev_err(dev, "failed insert local address bridge forwarding table\n");
+
+	if (br->dev->addr_assign_type != NET_ADDR_SET) {
+		/* Ask for permission to use this MAC address now, even if we
+		 * don't end up choosing it below.
+		 */
+		err = dev_pre_changeaddr_notify(br->dev, dev->dev_addr, extack);
+		if (err)
+			goto err6;
+	}
+
+	err = nbp_vlan_init(p, extack);
+	if (err) {
+		netdev_err(dev, "failed to initialize vlan filtering on this port\n");
+		goto err6;
+	}
+
+	spin_lock_bh(&br->lock);
+	changed_addr = br_stp_recalculate_bridge_id(br);
+
+	if (netif_running(dev) && netif_oper_up(dev) &&
+	    (br->dev->flags & IFF_UP))
+		br_stp_enable_port(p);
+	spin_unlock_bh(&br->lock);
+
+	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
+
+	if (changed_addr)
+		call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
+
+	br_mtu_auto_adjust(br);
+	br_set_gso_limits(br);
+
+	kobject_uevent(&p->kobj, KOBJ_ADD);
+
+	return 0;
+
+err6:
+	if (fdb_synced)
+		br_fdb_unsync_static(br, p);
+	list_del_rcu(&p->list);
+	br_fdb_delete_by_port(br, p, 0, 1);
+	nbp_update_port_count(br);
+	netdev_upper_dev_unlink(dev, br->dev);
+err5:
+	dev->priv_flags &= ~IFF_BRIDGE_PORT;
+	netdev_rx_handler_unregister(dev);
+err4:
+	br_netpoll_disable(p);
+err3:
+	sysfs_remove_link(br->ifobj, p->dev->name);
+err2:
+	br_multicast_del_port(p);
+	netdev_put(dev, &p->dev_tracker);
+	kobject_put(&p->kobj);
+	dev_set_allmulti(dev, -1);
+err1:
+	return err;
+}
+
+/* called with RTNL */
+int br_del_if(struct net_bridge *br, struct net_device *dev)
+{
+	struct net_bridge_port *p;
+	bool changed_addr;
+
+	p = br_port_get_rtnl(dev);
+	if (!p || p->br != br)
+		return -EINVAL;
+
+	/* Since more than one interface can be attached to a bridge,
+	 * there still maybe an alternate path for netconsole to use;
+	 * therefore there is no reason for a NETDEV_RELEASE event.
+	 */
+	del_nbp(p);
+
+	br_mtu_auto_adjust(br);
+	br_set_gso_limits(br);
+
+	spin_lock_bh(&br->lock);
+	changed_addr = br_stp_recalculate_bridge_id(br);
+	spin_unlock_bh(&br->lock);
+
+	if (changed_addr)
+		call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
+
+	netdev_update_features(br->dev);
+
+	return 0;
+}
+
+void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
+{
+	struct net_bridge *br = p->br;
+
+	if (mask & BR_AUTO_MASK)
+		nbp_update_port_count(br);
+
+	if (mask & BR_NEIGH_SUPPRESS)
+		br_recalculate_neigh_suppress_enabled(br);
+}
+
+bool br_port_flag_is_set(const struct net_device *dev, unsigned long flag)
+{
+	struct net_bridge_port *p;
+
+	p = br_port_get_rtnl_rcu(dev);
+	if (!p)
+		return false;
+
+	return p->flags & flag;
+}
+EXPORT_SYMBOL_GPL(br_port_flag_is_set);