1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Userspace interface
4 * Linux ethernet bridge
5 *
6 * Authors:
7 * Lennert Buytenhek <buytenh@gnu.org>
8 */
9
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>
21#include <net/dsa.h>
22#include <net/sock.h>
23#include <linux/if_vlan.h>
24#include <net/switchdev.h>
25#include <net/net_namespace.h>
26
27#include "br_private.h"
28
29/*
30 * Determine initial path cost based on speed.
31 * using recommendations from 802.1d standard
32 *
33 * Since driver might sleep need to not be holding any locks.
34 */
35static int port_cost(struct net_device *dev)
36{
37 struct ethtool_link_ksettings ecmd;
38
39 if (!__ethtool_get_link_ksettings(dev, link_ksettings: &ecmd)) {
40 switch (ecmd.base.speed) {
41 case SPEED_10000:
42 return 2;
43 case SPEED_5000:
44 return 3;
45 case SPEED_2500:
46 return 4;
47 case SPEED_1000:
48 return 5;
49 case SPEED_100:
50 return 19;
51 case SPEED_10:
52 return 100;
53 case SPEED_UNKNOWN:
54 return 100;
55 default:
56 if (ecmd.base.speed > SPEED_10000)
57 return 1;
58 }
59 }
60
61 /* Old silly heuristics based on name */
62 if (!strncmp(dev->name, "lec", 3))
63 return 7;
64
65 if (!strncmp(dev->name, "plip", 4))
66 return 2500;
67
68 return 100; /* assume old 10Mbps */
69}
70
71
72/* Check for port carrier transitions. */
73void br_port_carrier_check(struct net_bridge_port *p, bool *notified)
74{
75 struct net_device *dev = p->dev;
76 struct net_bridge *br = p->br;
77
78 if (!(p->flags & BR_ADMIN_COST) &&
79 netif_running(dev) && netif_oper_up(dev))
80 p->path_cost = port_cost(dev);
81
82 *notified = false;
83 if (!netif_running(dev: br->dev))
84 return;
85
86 spin_lock_bh(lock: &br->lock);
87 if (netif_running(dev) && netif_oper_up(dev)) {
88 if (p->state == BR_STATE_DISABLED) {
89 br_stp_enable_port(p);
90 *notified = true;
91 }
92 } else {
93 if (p->state != BR_STATE_DISABLED) {
94 br_stp_disable_port(p);
95 *notified = true;
96 }
97 }
98 spin_unlock_bh(lock: &br->lock);
99}
100
101static void br_port_set_promisc(struct net_bridge_port *p)
102{
103 int err = 0;
104
105 if (br_promisc_port(p))
106 return;
107
108 err = dev_set_promiscuity(dev: p->dev, inc: 1);
109 if (err)
110 return;
111
112 br_fdb_unsync_static(br: p->br, p);
113 p->flags |= BR_PROMISC;
114}
115
116static void br_port_clear_promisc(struct net_bridge_port *p)
117{
118 int err;
119
120 /* Check if the port is already non-promisc or if it doesn't
121 * support UNICAST filtering. Without unicast filtering support
122 * we'll end up re-enabling promisc mode anyway, so just check for
123 * it here.
124 */
125 if (!br_promisc_port(p) || !(p->dev->priv_flags & IFF_UNICAST_FLT))
126 return;
127
128 /* Since we'll be clearing the promisc mode, program the port
129 * first so that we don't have interruption in traffic.
130 */
131 err = br_fdb_sync_static(br: p->br, p);
132 if (err)
133 return;
134
135 dev_set_promiscuity(dev: p->dev, inc: -1);
136 p->flags &= ~BR_PROMISC;
137}
138
139/* When a port is added or removed or when certain port flags
140 * change, this function is called to automatically manage
141 * promiscuity setting of all the bridge ports. We are always called
142 * under RTNL so can skip using rcu primitives.
143 */
144void br_manage_promisc(struct net_bridge *br)
145{
146 struct net_bridge_port *p;
147 bool set_all = false;
148
149 /* If vlan filtering is disabled or bridge interface is placed
150 * into promiscuous mode, place all ports in promiscuous mode.
151 */
152 if ((br->dev->flags & IFF_PROMISC) || !br_vlan_enabled(dev: br->dev))
153 set_all = true;
154
155 list_for_each_entry(p, &br->port_list, list) {
156 if (set_all) {
157 br_port_set_promisc(p);
158 } else {
159 /* If the number of auto-ports is <= 1, then all other
160 * ports will have their output configuration
161 * statically specified through fdbs. Since ingress
162 * on the auto-port becomes forwarding/egress to other
163 * ports and egress configuration is statically known,
164 * we can say that ingress configuration of the
165 * auto-port is also statically known.
166 * This lets us disable promiscuous mode and write
167 * this config to hw.
168 */
169 if ((p->dev->priv_flags & IFF_UNICAST_FLT) &&
170 (br->auto_cnt == 0 ||
171 (br->auto_cnt == 1 && br_auto_port(p))))
172 br_port_clear_promisc(p);
173 else
174 br_port_set_promisc(p);
175 }
176 }
177}
178
179int nbp_backup_change(struct net_bridge_port *p,
180 struct net_device *backup_dev)
181{
182 struct net_bridge_port *old_backup = rtnl_dereference(p->backup_port);
183 struct net_bridge_port *backup_p = NULL;
184
185 ASSERT_RTNL();
186
187 if (backup_dev) {
188 if (!netif_is_bridge_port(dev: backup_dev))
189 return -ENOENT;
190
191 backup_p = br_port_get_rtnl(dev: backup_dev);
192 if (backup_p->br != p->br)
193 return -EINVAL;
194 }
195
196 if (p == backup_p)
197 return -EINVAL;
198
199 if (old_backup == backup_p)
200 return 0;
201
202 /* if the backup link is already set, clear it */
203 if (old_backup)
204 old_backup->backup_redirected_cnt--;
205
206 if (backup_p)
207 backup_p->backup_redirected_cnt++;
208 rcu_assign_pointer(p->backup_port, backup_p);
209
210 return 0;
211}
212
213static void nbp_backup_clear(struct net_bridge_port *p)
214{
215 nbp_backup_change(p, NULL);
216 if (p->backup_redirected_cnt) {
217 struct net_bridge_port *cur_p;
218
219 list_for_each_entry(cur_p, &p->br->port_list, list) {
220 struct net_bridge_port *backup_p;
221
222 backup_p = rtnl_dereference(cur_p->backup_port);
223 if (backup_p == p)
224 nbp_backup_change(p: cur_p, NULL);
225 }
226 }
227
228 WARN_ON(rcu_access_pointer(p->backup_port) || p->backup_redirected_cnt);
229}
230
231static void nbp_update_port_count(struct net_bridge *br)
232{
233 struct net_bridge_port *p;
234 u32 cnt = 0;
235
236 list_for_each_entry(p, &br->port_list, list) {
237 if (br_auto_port(p))
238 cnt++;
239 }
240 if (br->auto_cnt != cnt) {
241 br->auto_cnt = cnt;
242 br_manage_promisc(br);
243 }
244}
245
246static void nbp_delete_promisc(struct net_bridge_port *p)
247{
248 /* If port is currently promiscuous, unset promiscuity.
249 * Otherwise, it is a static port so remove all addresses
250 * from it.
251 */
252 dev_set_allmulti(dev: p->dev, inc: -1);
253 if (br_promisc_port(p))
254 dev_set_promiscuity(dev: p->dev, inc: -1);
255 else
256 br_fdb_unsync_static(br: p->br, p);
257}
258
259static void release_nbp(struct kobject *kobj)
260{
261 struct net_bridge_port *p
262 = container_of(kobj, struct net_bridge_port, kobj);
263 kfree(objp: p);
264}
265
266static void brport_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
267{
268 struct net_bridge_port *p = kobj_to_brport(kobj);
269
270 net_ns_get_ownership(net: dev_net(dev: p->dev), uid, gid);
271}
272
273static const struct kobj_type brport_ktype = {
274#ifdef CONFIG_SYSFS
275 .sysfs_ops = &brport_sysfs_ops,
276#endif
277 .release = release_nbp,
278 .get_ownership = brport_get_ownership,
279};
280
281static void destroy_nbp(struct net_bridge_port *p)
282{
283 struct net_device *dev = p->dev;
284
285 p->br = NULL;
286 p->dev = NULL;
287 netdev_put(dev, tracker: &p->dev_tracker);
288
289 kobject_put(kobj: &p->kobj);
290}
291
292static void destroy_nbp_rcu(struct rcu_head *head)
293{
294 struct net_bridge_port *p =
295 container_of(head, struct net_bridge_port, rcu);
296 destroy_nbp(p);
297}
298
299static unsigned get_max_headroom(struct net_bridge *br)
300{
301 unsigned max_headroom = 0;
302 struct net_bridge_port *p;
303
304 list_for_each_entry(p, &br->port_list, list) {
305 unsigned dev_headroom = netdev_get_fwd_headroom(dev: p->dev);
306
307 if (dev_headroom > max_headroom)
308 max_headroom = dev_headroom;
309 }
310
311 return max_headroom;
312}
313
314static void update_headroom(struct net_bridge *br, int new_hr)
315{
316 struct net_bridge_port *p;
317
318 list_for_each_entry(p, &br->port_list, list)
319 netdev_set_rx_headroom(dev: p->dev, new_hr);
320
321 br->dev->needed_headroom = new_hr;
322}
323
324/* Delete port(interface) from bridge is done in two steps.
325 * via RCU. First step, marks device as down. That deletes
326 * all the timers and stops new packets from flowing through.
327 *
328 * Final cleanup doesn't occur until after all CPU's finished
329 * processing packets.
330 *
331 * Protected from multiple admin operations by RTNL mutex
332 */
333static void del_nbp(struct net_bridge_port *p)
334{
335 struct net_bridge *br = p->br;
336 struct net_device *dev = p->dev;
337
338 sysfs_remove_link(kobj: br->ifobj, name: p->dev->name);
339
340 nbp_delete_promisc(p);
341
342 spin_lock_bh(lock: &br->lock);
343 br_stp_disable_port(p);
344 spin_unlock_bh(lock: &br->lock);
345
346 br_mrp_port_del(br, p);
347 br_cfm_port_del(br, p);
348
349 br_ifinfo_notify(RTM_DELLINK, NULL, port: p);
350
351 list_del_rcu(entry: &p->list);
352 if (netdev_get_fwd_headroom(dev) == br->dev->needed_headroom)
353 update_headroom(br, new_hr: get_max_headroom(br));
354 netdev_reset_rx_headroom(dev);
355
356 nbp_vlan_flush(port: p);
357 br_fdb_delete_by_port(br, p, vid: 0, do_all: 1);
358 switchdev_deferred_process();
359 nbp_backup_clear(p);
360
361 nbp_update_port_count(br);
362
363 netdev_upper_dev_unlink(dev, upper_dev: br->dev);
364
365 dev->priv_flags &= ~IFF_BRIDGE_PORT;
366
367 netdev_rx_handler_unregister(dev);
368
369 br_multicast_del_port(port: p);
370
371 kobject_uevent(kobj: &p->kobj, action: KOBJ_REMOVE);
372 kobject_del(kobj: &p->kobj);
373
374 br_netpoll_disable(p);
375
376 call_rcu(head: &p->rcu, func: destroy_nbp_rcu);
377}
378
379/* Delete bridge device */
380void br_dev_delete(struct net_device *dev, struct list_head *head)
381{
382 struct net_bridge *br = netdev_priv(dev);
383 struct net_bridge_port *p, *n;
384
385 list_for_each_entry_safe(p, n, &br->port_list, list) {
386 del_nbp(p);
387 }
388
389 br_mst_uninit(br);
390 br_recalculate_neigh_suppress_enabled(br);
391
392 br_fdb_delete_by_port(br, NULL, vid: 0, do_all: 1);
393
394 cancel_delayed_work_sync(dwork: &br->gc_work);
395
396 br_sysfs_delbr(dev: br->dev);
397 unregister_netdevice_queue(dev: br->dev, head);
398}
399
400/* find an available port number */
401static int find_portno(struct net_bridge *br)
402{
403 int index;
404 struct net_bridge_port *p;
405 unsigned long *inuse;
406
407 inuse = bitmap_zalloc(BR_MAX_PORTS, GFP_KERNEL);
408 if (!inuse)
409 return -ENOMEM;
410
411 __set_bit(0, inuse); /* zero is reserved */
412 list_for_each_entry(p, &br->port_list, list)
413 __set_bit(p->port_no, inuse);
414
415 index = find_first_zero_bit(addr: inuse, BR_MAX_PORTS);
416 bitmap_free(bitmap: inuse);
417
418 return (index >= BR_MAX_PORTS) ? -EXFULL : index;
419}
420
421/* called with RTNL but without bridge lock */
422static struct net_bridge_port *new_nbp(struct net_bridge *br,
423 struct net_device *dev)
424{
425 struct net_bridge_port *p;
426 int index, err;
427
428 index = find_portno(br);
429 if (index < 0)
430 return ERR_PTR(error: index);
431
432 p = kzalloc(sizeof(*p), GFP_KERNEL);
433 if (p == NULL)
434 return ERR_PTR(error: -ENOMEM);
435
436 p->br = br;
437 netdev_hold(dev, tracker: &p->dev_tracker, GFP_KERNEL);
438 p->dev = dev;
439 p->path_cost = port_cost(dev);
440 p->priority = 0x8000 >> BR_PORT_BITS;
441 p->port_no = index;
442 p->flags = BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD | BR_BCAST_FLOOD;
443 br_init_port(p);
444 br_set_state(p, BR_STATE_DISABLED);
445 br_stp_port_timer_init(p);
446 err = br_multicast_add_port(port: p);
447 if (err) {
448 netdev_put(dev, tracker: &p->dev_tracker);
449 kfree(objp: p);
450 p = ERR_PTR(error: err);
451 }
452
453 return p;
454}
455
456int br_add_bridge(struct net *net, const char *name)
457{
458 struct net_device *dev;
459 int res;
460
461 dev = alloc_netdev(sizeof(struct net_bridge), name, NET_NAME_UNKNOWN,
462 br_dev_setup);
463
464 if (!dev)
465 return -ENOMEM;
466
467 dev_net_set(dev, net);
468 dev->rtnl_link_ops = &br_link_ops;
469
470 res = register_netdevice(dev);
471 if (res)
472 free_netdev(dev);
473 return res;
474}
475
476int br_del_bridge(struct net *net, const char *name)
477{
478 struct net_device *dev;
479 int ret = 0;
480
481 dev = __dev_get_by_name(net, name);
482 if (dev == NULL)
483 ret = -ENXIO; /* Could not find device */
484
485 else if (!netif_is_bridge_master(dev)) {
486 /* Attempt to delete non bridge device! */
487 ret = -EPERM;
488 }
489
490 else if (dev->flags & IFF_UP) {
491 /* Not shutdown yet. */
492 ret = -EBUSY;
493 }
494
495 else
496 br_dev_delete(dev, NULL);
497
498 return ret;
499}
500
501/* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
502static int br_mtu_min(const struct net_bridge *br)
503{
504 const struct net_bridge_port *p;
505 int ret_mtu = 0;
506
507 list_for_each_entry(p, &br->port_list, list)
508 if (!ret_mtu || ret_mtu > p->dev->mtu)
509 ret_mtu = p->dev->mtu;
510
511 return ret_mtu ? ret_mtu : ETH_DATA_LEN;
512}
513
514void br_mtu_auto_adjust(struct net_bridge *br)
515{
516 ASSERT_RTNL();
517
518 /* if the bridge MTU was manually configured don't mess with it */
519 if (br_opt_get(br, opt: BROPT_MTU_SET_BY_USER))
520 return;
521
522 /* change to the minimum MTU and clear the flag which was set by
523 * the bridge ndo_change_mtu callback
524 */
525 dev_set_mtu(br->dev, br_mtu_min(br));
526 br_opt_toggle(br, opt: BROPT_MTU_SET_BY_USER, on: false);
527}
528
529/*
530 * Recomputes features using slave's features
531 */
532netdev_features_t br_features_recompute(struct net_bridge *br,
533 netdev_features_t features)
534{
535 struct net_bridge_port *p;
536 netdev_features_t mask;
537
538 if (list_empty(head: &br->port_list))
539 return features;
540
541 mask = features;
542 features &= ~NETIF_F_ONE_FOR_ALL;
543
544 list_for_each_entry(p, &br->port_list, list) {
545 features = netdev_increment_features(all: features,
546 one: p->dev->features, mask);
547 }
548 features = netdev_add_tso_features(features, mask);
549
550 return features;
551}
552
553/* called with RTNL */
554int br_add_if(struct net_bridge *br, struct net_device *dev,
555 struct netlink_ext_ack *extack)
556{
557 struct net_bridge_port *p;
558 int err = 0;
559 unsigned br_hr, dev_hr;
560 bool changed_addr, fdb_synced = false;
561
562 /* Don't allow bridging non-ethernet like devices. */
563 if ((dev->flags & IFF_LOOPBACK) ||
564 dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
565 !is_valid_ether_addr(addr: dev->dev_addr))
566 return -EINVAL;
567
568 /* No bridging of bridges */
569 if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit) {
570 NL_SET_ERR_MSG(extack,
571 "Can not enslave a bridge to a bridge");
572 return -ELOOP;
573 }
574
575 /* Device has master upper dev */
576 if (netdev_master_upper_dev_get(dev))
577 return -EBUSY;
578
579 /* No bridging devices that dislike that (e.g. wireless) */
580 if (dev->priv_flags & IFF_DONT_BRIDGE) {
581 NL_SET_ERR_MSG(extack,
582 "Device does not allow enslaving to a bridge");
583 return -EOPNOTSUPP;
584 }
585
586 p = new_nbp(br, dev);
587 if (IS_ERR(ptr: p))
588 return PTR_ERR(ptr: p);
589
590 call_netdevice_notifiers(val: NETDEV_JOIN, dev);
591
592 err = dev_set_allmulti(dev, inc: 1);
593 if (err) {
594 br_multicast_del_port(port: p);
595 netdev_put(dev, tracker: &p->dev_tracker);
596 kfree(objp: p); /* kobject not yet init'd, manually free */
597 goto err1;
598 }
599
600 err = kobject_init_and_add(kobj: &p->kobj, ktype: &brport_ktype, parent: &(dev->dev.kobj),
601 SYSFS_BRIDGE_PORT_ATTR);
602 if (err)
603 goto err2;
604
605 err = br_sysfs_addif(p);
606 if (err)
607 goto err2;
608
609 err = br_netpoll_enable(p);
610 if (err)
611 goto err3;
612
613 err = netdev_rx_handler_register(dev, rx_handler: br_get_rx_handler(dev), rx_handler_data: p);
614 if (err)
615 goto err4;
616
617 dev->priv_flags |= IFF_BRIDGE_PORT;
618
619 err = netdev_master_upper_dev_link(dev, upper_dev: br->dev, NULL, NULL, extack);
620 if (err)
621 goto err5;
622
623 dev_disable_lro(dev);
624
625 list_add_rcu(new: &p->list, head: &br->port_list);
626
627 nbp_update_port_count(br);
628 if (!br_promisc_port(p) && (p->dev->priv_flags & IFF_UNICAST_FLT)) {
629 /* When updating the port count we also update all ports'
630 * promiscuous mode.
631 * A port leaving promiscuous mode normally gets the bridge's
632 * fdb synced to the unicast filter (if supported), however,
633 * `br_port_clear_promisc` does not distinguish between
634 * non-promiscuous ports and *new* ports, so we need to
635 * sync explicitly here.
636 */
637 fdb_synced = br_fdb_sync_static(br, p) == 0;
638 if (!fdb_synced)
639 netdev_err(dev, format: "failed to sync bridge static fdb addresses to this port\n");
640 }
641
642 br_hr = br->dev->needed_headroom;
643 dev_hr = netdev_get_fwd_headroom(dev);
644 if (br_hr < dev_hr)
645 update_headroom(br, new_hr: dev_hr);
646 else
647 netdev_set_rx_headroom(dev, new_hr: br_hr);
648
649 if (br_fdb_add_local(br, source: p, addr: dev->dev_addr, vid: 0))
650 netdev_err(dev, format: "failed insert local address bridge forwarding table\n");
651
652 if (br->dev->addr_assign_type != NET_ADDR_SET) {
653 /* Ask for permission to use this MAC address now, even if we
654 * don't end up choosing it below.
655 */
656 err = netif_pre_changeaddr_notify(dev: br->dev, addr: dev->dev_addr,
657 extack);
658 if (err)
659 goto err6;
660 }
661
662 err = nbp_vlan_init(port: p, extack);
663 if (err) {
664 netdev_err(dev, format: "failed to initialize vlan filtering on this port\n");
665 goto err6;
666 }
667
668 spin_lock_bh(lock: &br->lock);
669 changed_addr = br_stp_recalculate_bridge_id(br);
670
671 if (netif_running(dev) && netif_oper_up(dev) &&
672 (br->dev->flags & IFF_UP))
673 br_stp_enable_port(p);
674 spin_unlock_bh(lock: &br->lock);
675
676 br_ifinfo_notify(RTM_NEWLINK, NULL, port: p);
677
678 if (changed_addr)
679 call_netdevice_notifiers(val: NETDEV_CHANGEADDR, dev: br->dev);
680
681 br_mtu_auto_adjust(br);
682
683 netdev_compute_master_upper_features(dev: br->dev, update_header: false);
684
685 kobject_uevent(kobj: &p->kobj, action: KOBJ_ADD);
686
687 return 0;
688
689err6:
690 if (fdb_synced)
691 br_fdb_unsync_static(br, p);
692 list_del_rcu(entry: &p->list);
693 br_fdb_delete_by_port(br, p, vid: 0, do_all: 1);
694 nbp_update_port_count(br);
695 netdev_upper_dev_unlink(dev, upper_dev: br->dev);
696err5:
697 dev->priv_flags &= ~IFF_BRIDGE_PORT;
698 netdev_rx_handler_unregister(dev);
699err4:
700 br_netpoll_disable(p);
701err3:
702 sysfs_remove_link(kobj: br->ifobj, name: p->dev->name);
703err2:
704 br_multicast_del_port(port: p);
705 netdev_put(dev, tracker: &p->dev_tracker);
706 kobject_put(kobj: &p->kobj);
707 dev_set_allmulti(dev, inc: -1);
708err1:
709 return err;
710}
711
712/* called with RTNL */
713int br_del_if(struct net_bridge *br, struct net_device *dev)
714{
715 struct net_bridge_port *p;
716 bool changed_addr;
717
718 p = br_port_get_rtnl(dev);
719 if (!p || p->br != br)
720 return -EINVAL;
721
722 /* Since more than one interface can be attached to a bridge,
723 * there still maybe an alternate path for netconsole to use;
724 * therefore there is no reason for a NETDEV_RELEASE event.
725 */
726 del_nbp(p);
727
728 br_mtu_auto_adjust(br);
729
730 spin_lock_bh(lock: &br->lock);
731 changed_addr = br_stp_recalculate_bridge_id(br);
732 spin_unlock_bh(lock: &br->lock);
733
734 if (changed_addr)
735 call_netdevice_notifiers(val: NETDEV_CHANGEADDR, dev: br->dev);
736
737 netdev_compute_master_upper_features(dev: br->dev, update_header: false);
738
739 return 0;
740}
741
742void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
743{
744 struct net_bridge *br = p->br;
745
746 if (mask & BR_AUTO_MASK)
747 nbp_update_port_count(br);
748
749 if (mask & (BR_NEIGH_SUPPRESS | BR_NEIGH_VLAN_SUPPRESS))
750 br_recalculate_neigh_suppress_enabled(br);
751}
752
753bool br_port_flag_is_set(const struct net_device *dev, unsigned long flag)
754{
755 struct net_bridge_port *p;
756
757 p = br_port_get_rtnl_rcu(dev);
758 if (!p)
759 return false;
760
761 return p->flags & flag;
762}
763EXPORT_SYMBOL_GPL(br_port_flag_is_set);
764

source code of linux/net/bridge/br_if.c