1 // SPDX-License-Identifier: GPL-2.0-or-later
4 * Linux ethernet bridge
7 * Lennert Buytenhek <buytenh@gnu.org>
10 #include <linux/kernel.h>
11 #include <linux/netdevice.h>
12 #include <linux/etherdevice.h>
13 #include <linux/netpoll.h>
14 #include <linux/ethtool.h>
15 #include <linux/if_arp.h>
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/rtnetlink.h>
19 #include <linux/if_ether.h>
20 #include <linux/slab.h>
23 #include <linux/if_vlan.h>
24 #include <net/switchdev.h>
25 #include <net/net_namespace.h>
27 #include "br_private.h"
30 * Determine initial path cost based on speed.
31 * using recommendations from 802.1d standard
33 * Since driver might sleep need to not be holding any locks.
35 static int port_cost(struct net_device *dev)
37 struct ethtool_link_ksettings ecmd;
39 if (!__ethtool_get_link_ksettings(dev, &ecmd)) {
40 switch (ecmd.base.speed) {
52 /* Old silly heuristics based on name */
53 if (!strncmp(dev->name, "lec", 3))
56 if (!strncmp(dev->name, "plip", 4))
59 return 100; /* assume old 10Mbps */
63 /* Check for port carrier transitions. */
64 void br_port_carrier_check(struct net_bridge_port *p, bool *notified)
66 struct net_device *dev = p->dev;
67 struct net_bridge *br = p->br;
69 if (!(p->flags & BR_ADMIN_COST) &&
70 netif_running(dev) && netif_oper_up(dev))
71 p->path_cost = port_cost(dev);
74 if (!netif_running(br->dev))
77 spin_lock_bh(&br->lock);
78 if (netif_running(dev) && netif_oper_up(dev)) {
79 if (p->state == BR_STATE_DISABLED) {
80 br_stp_enable_port(p);
84 if (p->state != BR_STATE_DISABLED) {
85 br_stp_disable_port(p);
89 spin_unlock_bh(&br->lock);
92 static void br_port_set_promisc(struct net_bridge_port *p)
96 if (br_promisc_port(p))
99 err = dev_set_promiscuity(p->dev, 1);
103 br_fdb_unsync_static(p->br, p);
104 p->flags |= BR_PROMISC;
107 static void br_port_clear_promisc(struct net_bridge_port *p)
111 /* Check if the port is already non-promisc or if it doesn't
112 * support UNICAST filtering. Without unicast filtering support
113 * we'll end up re-enabling promisc mode anyway, so just check for
116 if (!br_promisc_port(p) || !(p->dev->priv_flags & IFF_UNICAST_FLT))
119 /* Since we'll be clearing the promisc mode, program the port
120 * first so that we don't have interruption in traffic.
122 err = br_fdb_sync_static(p->br, p);
126 dev_set_promiscuity(p->dev, -1);
127 p->flags &= ~BR_PROMISC;
130 /* When a port is added or removed or when certain port flags
131 * change, this function is called to automatically manage
132 * promiscuity setting of all the bridge ports. We are always called
133 * under RTNL so can skip using rcu primitives.
135 void br_manage_promisc(struct net_bridge *br)
137 struct net_bridge_port *p;
138 bool set_all = false;
140 /* If vlan filtering is disabled or bridge interface is placed
141 * into promiscuous mode, place all ports in promiscuous mode.
143 if ((br->dev->flags & IFF_PROMISC) || !br_vlan_enabled(br->dev))
146 list_for_each_entry(p, &br->port_list, list) {
148 br_port_set_promisc(p);
150 /* If the number of auto-ports is <= 1, then all other
151 * ports will have their output configuration
152 * statically specified through fdbs. Since ingress
153 * on the auto-port becomes forwarding/egress to other
154 * ports and egress configuration is statically known,
155 * we can say that ingress configuration of the
156 * auto-port is also statically known.
157 * This lets us disable promiscuous mode and write
160 if (br->auto_cnt == 0 ||
161 (br->auto_cnt == 1 && br_auto_port(p)))
162 br_port_clear_promisc(p);
164 br_port_set_promisc(p);
169 int nbp_backup_change(struct net_bridge_port *p,
170 struct net_device *backup_dev)
172 struct net_bridge_port *old_backup = rtnl_dereference(p->backup_port);
173 struct net_bridge_port *backup_p = NULL;
178 if (!netif_is_bridge_port(backup_dev))
181 backup_p = br_port_get_rtnl(backup_dev);
182 if (backup_p->br != p->br)
189 if (old_backup == backup_p)
192 /* if the backup link is already set, clear it */
194 old_backup->backup_redirected_cnt--;
197 backup_p->backup_redirected_cnt++;
198 rcu_assign_pointer(p->backup_port, backup_p);
203 static void nbp_backup_clear(struct net_bridge_port *p)
205 nbp_backup_change(p, NULL);
206 if (p->backup_redirected_cnt) {
207 struct net_bridge_port *cur_p;
209 list_for_each_entry(cur_p, &p->br->port_list, list) {
210 struct net_bridge_port *backup_p;
212 backup_p = rtnl_dereference(cur_p->backup_port);
214 nbp_backup_change(cur_p, NULL);
218 WARN_ON(rcu_access_pointer(p->backup_port) || p->backup_redirected_cnt);
221 static void nbp_update_port_count(struct net_bridge *br)
223 struct net_bridge_port *p;
226 list_for_each_entry(p, &br->port_list, list) {
230 if (br->auto_cnt != cnt) {
232 br_manage_promisc(br);
236 static void nbp_delete_promisc(struct net_bridge_port *p)
238 /* If port is currently promiscuous, unset promiscuity.
239 * Otherwise, it is a static port so remove all addresses
242 dev_set_allmulti(p->dev, -1);
243 if (br_promisc_port(p))
244 dev_set_promiscuity(p->dev, -1);
246 br_fdb_unsync_static(p->br, p);
249 static void release_nbp(struct kobject *kobj)
251 struct net_bridge_port *p
252 = container_of(kobj, struct net_bridge_port, kobj);
256 static void brport_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
258 struct net_bridge_port *p = kobj_to_brport(kobj);
260 net_ns_get_ownership(dev_net(p->dev), uid, gid);
263 static struct kobj_type brport_ktype = {
265 .sysfs_ops = &brport_sysfs_ops,
267 .release = release_nbp,
268 .get_ownership = brport_get_ownership,
271 static void destroy_nbp(struct net_bridge_port *p)
273 struct net_device *dev = p->dev;
279 kobject_put(&p->kobj);
282 static void destroy_nbp_rcu(struct rcu_head *head)
284 struct net_bridge_port *p =
285 container_of(head, struct net_bridge_port, rcu);
289 static unsigned get_max_headroom(struct net_bridge *br)
291 unsigned max_headroom = 0;
292 struct net_bridge_port *p;
294 list_for_each_entry(p, &br->port_list, list) {
295 unsigned dev_headroom = netdev_get_fwd_headroom(p->dev);
297 if (dev_headroom > max_headroom)
298 max_headroom = dev_headroom;
304 static void update_headroom(struct net_bridge *br, int new_hr)
306 struct net_bridge_port *p;
308 list_for_each_entry(p, &br->port_list, list)
309 netdev_set_rx_headroom(p->dev, new_hr);
311 br->dev->needed_headroom = new_hr;
314 /* Delete port(interface) from bridge is done in two steps.
315 * via RCU. First step, marks device as down. That deletes
316 * all the timers and stops new packets from flowing through.
318 * Final cleanup doesn't occur until after all CPU's finished
319 * processing packets.
321 * Protected from multiple admin operations by RTNL mutex
323 static void del_nbp(struct net_bridge_port *p)
325 struct net_bridge *br = p->br;
326 struct net_device *dev = p->dev;
328 sysfs_remove_link(br->ifobj, p->dev->name);
330 nbp_delete_promisc(p);
332 spin_lock_bh(&br->lock);
333 br_stp_disable_port(p);
334 spin_unlock_bh(&br->lock);
336 br_mrp_port_del(br, p);
338 br_ifinfo_notify(RTM_DELLINK, NULL, p);
340 list_del_rcu(&p->list);
341 if (netdev_get_fwd_headroom(dev) == br->dev->needed_headroom)
342 update_headroom(br, get_max_headroom(br));
343 netdev_reset_rx_headroom(dev);
346 br_fdb_delete_by_port(br, p, 0, 1);
347 switchdev_deferred_process();
350 nbp_update_port_count(br);
352 netdev_upper_dev_unlink(dev, br->dev);
354 dev->priv_flags &= ~IFF_BRIDGE_PORT;
356 netdev_rx_handler_unregister(dev);
358 br_multicast_del_port(p);
360 kobject_uevent(&p->kobj, KOBJ_REMOVE);
361 kobject_del(&p->kobj);
363 br_netpoll_disable(p);
365 call_rcu(&p->rcu, destroy_nbp_rcu);
368 /* Delete bridge device */
369 void br_dev_delete(struct net_device *dev, struct list_head *head)
371 struct net_bridge *br = netdev_priv(dev);
372 struct net_bridge_port *p, *n;
374 list_for_each_entry_safe(p, n, &br->port_list, list) {
378 br_recalculate_neigh_suppress_enabled(br);
380 br_fdb_delete_by_port(br, NULL, 0, 1);
382 cancel_delayed_work_sync(&br->gc_work);
384 br_sysfs_delbr(br->dev);
385 unregister_netdevice_queue(br->dev, head);
388 /* find an available port number */
389 static int find_portno(struct net_bridge *br)
392 struct net_bridge_port *p;
393 unsigned long *inuse;
395 inuse = bitmap_zalloc(BR_MAX_PORTS, GFP_KERNEL);
399 set_bit(0, inuse); /* zero is reserved */
400 list_for_each_entry(p, &br->port_list, list) {
401 set_bit(p->port_no, inuse);
403 index = find_first_zero_bit(inuse, BR_MAX_PORTS);
406 return (index >= BR_MAX_PORTS) ? -EXFULL : index;
409 /* called with RTNL but without bridge lock */
410 static struct net_bridge_port *new_nbp(struct net_bridge *br,
411 struct net_device *dev)
413 struct net_bridge_port *p;
416 index = find_portno(br);
418 return ERR_PTR(index);
420 p = kzalloc(sizeof(*p), GFP_KERNEL);
422 return ERR_PTR(-ENOMEM);
427 p->path_cost = port_cost(dev);
428 p->priority = 0x8000 >> BR_PORT_BITS;
430 p->flags = BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD | BR_BCAST_FLOOD;
432 br_set_state(p, BR_STATE_DISABLED);
433 br_stp_port_timer_init(p);
434 err = br_multicast_add_port(p);
444 int br_add_bridge(struct net *net, const char *name)
446 struct net_device *dev;
449 dev = alloc_netdev(sizeof(struct net_bridge), name, NET_NAME_UNKNOWN,
455 dev_net_set(dev, net);
456 dev->rtnl_link_ops = &br_link_ops;
458 res = register_netdev(dev);
464 int br_del_bridge(struct net *net, const char *name)
466 struct net_device *dev;
470 dev = __dev_get_by_name(net, name);
472 ret = -ENXIO; /* Could not find device */
474 else if (!(dev->priv_flags & IFF_EBRIDGE)) {
475 /* Attempt to delete non bridge device! */
479 else if (dev->flags & IFF_UP) {
480 /* Not shutdown yet. */
485 br_dev_delete(dev, NULL);
491 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
492 static int br_mtu_min(const struct net_bridge *br)
494 const struct net_bridge_port *p;
497 list_for_each_entry(p, &br->port_list, list)
498 if (!ret_mtu || ret_mtu > p->dev->mtu)
499 ret_mtu = p->dev->mtu;
501 return ret_mtu ? ret_mtu : ETH_DATA_LEN;
504 void br_mtu_auto_adjust(struct net_bridge *br)
508 /* if the bridge MTU was manually configured don't mess with it */
509 if (br_opt_get(br, BROPT_MTU_SET_BY_USER))
512 /* change to the minimum MTU and clear the flag which was set by
513 * the bridge ndo_change_mtu callback
515 dev_set_mtu(br->dev, br_mtu_min(br));
516 br_opt_toggle(br, BROPT_MTU_SET_BY_USER, false);
519 static void br_set_gso_limits(struct net_bridge *br)
521 unsigned int gso_max_size = GSO_MAX_SIZE;
522 u16 gso_max_segs = GSO_MAX_SEGS;
523 const struct net_bridge_port *p;
525 list_for_each_entry(p, &br->port_list, list) {
526 gso_max_size = min(gso_max_size, p->dev->gso_max_size);
527 gso_max_segs = min(gso_max_segs, p->dev->gso_max_segs);
529 br->dev->gso_max_size = gso_max_size;
530 br->dev->gso_max_segs = gso_max_segs;
534 * Recomputes features using slave's features
536 netdev_features_t br_features_recompute(struct net_bridge *br,
537 netdev_features_t features)
539 struct net_bridge_port *p;
540 netdev_features_t mask;
542 if (list_empty(&br->port_list))
546 features &= ~NETIF_F_ONE_FOR_ALL;
548 list_for_each_entry(p, &br->port_list, list) {
549 features = netdev_increment_features(features,
550 p->dev->features, mask);
552 features = netdev_add_tso_features(features, mask);
557 /* called with RTNL */
558 int br_add_if(struct net_bridge *br, struct net_device *dev,
559 struct netlink_ext_ack *extack)
561 struct net_bridge_port *p;
563 unsigned br_hr, dev_hr;
564 bool changed_addr, fdb_synced = false;
566 /* Don't allow bridging non-ethernet like devices. */
567 if ((dev->flags & IFF_LOOPBACK) ||
568 dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
569 !is_valid_ether_addr(dev->dev_addr))
572 /* Also don't allow bridging of net devices that are DSA masters, since
573 * the bridge layer rx_handler prevents the DSA fake ethertype handler
574 * to be invoked, so we don't get the chance to strip off and parse the
575 * DSA switch tag protocol header (the bridge layer just returns
576 * RX_HANDLER_CONSUMED, stopping RX processing for these frames).
577 * The only case where that would not be an issue is when bridging can
578 * already be offloaded, such as when the DSA master is itself a DSA
579 * or plain switchdev port, and is bridged only with other ports from
580 * the same hardware device.
582 if (netdev_uses_dsa(dev)) {
583 list_for_each_entry(p, &br->port_list, list) {
584 if (!netdev_port_same_parent_id(dev, p->dev)) {
585 NL_SET_ERR_MSG(extack,
586 "Cannot do software bridging with a DSA master");
592 /* No bridging of bridges */
593 if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit) {
594 NL_SET_ERR_MSG(extack,
595 "Can not enslave a bridge to a bridge");
599 /* Device has master upper dev */
600 if (netdev_master_upper_dev_get(dev))
603 /* No bridging devices that dislike that (e.g. wireless) */
604 if (dev->priv_flags & IFF_DONT_BRIDGE) {
605 NL_SET_ERR_MSG(extack,
606 "Device does not allow enslaving to a bridge");
610 p = new_nbp(br, dev);
614 call_netdevice_notifiers(NETDEV_JOIN, dev);
616 err = dev_set_allmulti(dev, 1);
618 br_multicast_del_port(p);
619 kfree(p); /* kobject not yet init'd, manually free */
623 err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
624 SYSFS_BRIDGE_PORT_ATTR);
628 err = br_sysfs_addif(p);
632 err = br_netpoll_enable(p);
636 err = netdev_rx_handler_register(dev, br_get_rx_handler(dev), p);
640 dev->priv_flags |= IFF_BRIDGE_PORT;
642 err = netdev_master_upper_dev_link(dev, br->dev, NULL, NULL, extack);
646 err = nbp_switchdev_mark_set(p);
650 dev_disable_lro(dev);
652 list_add_rcu(&p->list, &br->port_list);
654 nbp_update_port_count(br);
655 if (!br_promisc_port(p) && (p->dev->priv_flags & IFF_UNICAST_FLT)) {
656 /* When updating the port count we also update all ports'
658 * A port leaving promiscuous mode normally gets the bridge's
659 * fdb synced to the unicast filter (if supported), however,
660 * `br_port_clear_promisc` does not distinguish between
661 * non-promiscuous ports and *new* ports, so we need to
662 * sync explicitly here.
664 fdb_synced = br_fdb_sync_static(br, p) == 0;
666 netdev_err(dev, "failed to sync bridge static fdb addresses to this port\n");
669 netdev_update_features(br->dev);
671 br_hr = br->dev->needed_headroom;
672 dev_hr = netdev_get_fwd_headroom(dev);
674 update_headroom(br, dev_hr);
676 netdev_set_rx_headroom(dev, br_hr);
678 if (br_fdb_insert(br, p, dev->dev_addr, 0))
679 netdev_err(dev, "failed insert local address bridge forwarding table\n");
681 if (br->dev->addr_assign_type != NET_ADDR_SET) {
682 /* Ask for permission to use this MAC address now, even if we
683 * don't end up choosing it below.
685 err = dev_pre_changeaddr_notify(br->dev, dev->dev_addr, extack);
690 err = nbp_vlan_init(p, extack);
692 netdev_err(dev, "failed to initialize vlan filtering on this port\n");
696 spin_lock_bh(&br->lock);
697 changed_addr = br_stp_recalculate_bridge_id(br);
699 if (netif_running(dev) && netif_oper_up(dev) &&
700 (br->dev->flags & IFF_UP))
701 br_stp_enable_port(p);
702 spin_unlock_bh(&br->lock);
704 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
707 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
709 br_mtu_auto_adjust(br);
710 br_set_gso_limits(br);
712 kobject_uevent(&p->kobj, KOBJ_ADD);
718 br_fdb_unsync_static(br, p);
719 list_del_rcu(&p->list);
720 br_fdb_delete_by_port(br, p, 0, 1);
721 nbp_update_port_count(br);
723 netdev_upper_dev_unlink(dev, br->dev);
725 dev->priv_flags &= ~IFF_BRIDGE_PORT;
726 netdev_rx_handler_unregister(dev);
728 br_netpoll_disable(p);
730 sysfs_remove_link(br->ifobj, p->dev->name);
732 br_multicast_del_port(p);
733 kobject_put(&p->kobj);
734 dev_set_allmulti(dev, -1);
740 /* called with RTNL */
741 int br_del_if(struct net_bridge *br, struct net_device *dev)
743 struct net_bridge_port *p;
746 p = br_port_get_rtnl(dev);
747 if (!p || p->br != br)
750 /* Since more than one interface can be attached to a bridge,
751 * there still maybe an alternate path for netconsole to use;
752 * therefore there is no reason for a NETDEV_RELEASE event.
756 br_mtu_auto_adjust(br);
757 br_set_gso_limits(br);
759 spin_lock_bh(&br->lock);
760 changed_addr = br_stp_recalculate_bridge_id(br);
761 spin_unlock_bh(&br->lock);
764 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
766 netdev_update_features(br->dev);
771 void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
773 struct net_bridge *br = p->br;
775 if (mask & BR_AUTO_MASK)
776 nbp_update_port_count(br);
778 if (mask & BR_NEIGH_SUPPRESS)
779 br_recalculate_neigh_suppress_enabled(br);
782 bool br_port_flag_is_set(const struct net_device *dev, unsigned long flag)
784 struct net_bridge_port *p;
786 p = br_port_get_rtnl_rcu(dev);
790 return p->flags & flag;
792 EXPORT_SYMBOL_GPL(br_port_flag_is_set);