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 */ 35 static int port_cost(struct net_device *dev) 36 { 37 struct ethtool_link_ksettings ecmd; 38 39 if (!__ethtool_get_link_ksettings(dev, &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. */ 73 void 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(br->dev)) 84 return; 85 86 spin_lock_bh(&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(&br->lock); 99 } 100 101 static 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(p->dev, 1); 109 if (err) 110 return; 111 112 br_fdb_unsync_static(p->br, p); 113 p->flags |= BR_PROMISC; 114 } 115 116 static 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(p->br, p); 132 if (err) 133 return; 134 135 dev_set_promiscuity(p->dev, -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 */ 144 void 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(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 (br->auto_cnt == 0 || 170 (br->auto_cnt == 1 && br_auto_port(p))) 171 br_port_clear_promisc(p); 172 else 173 br_port_set_promisc(p); 174 } 175 } 176 } 177 178 int nbp_backup_change(struct net_bridge_port *p, 179 struct net_device *backup_dev) 180 { 181 struct net_bridge_port *old_backup = rtnl_dereference(p->backup_port); 182 struct net_bridge_port *backup_p = NULL; 183 184 ASSERT_RTNL(); 185 186 if (backup_dev) { 187 if (!netif_is_bridge_port(backup_dev)) 188 return -ENOENT; 189 190 backup_p = br_port_get_rtnl(backup_dev); 191 if (backup_p->br != p->br) 192 return -EINVAL; 193 } 194 195 if (p == backup_p) 196 return -EINVAL; 197 198 if (old_backup == backup_p) 199 return 0; 200 201 /* if the backup link is already set, clear it */ 202 if (old_backup) 203 old_backup->backup_redirected_cnt--; 204 205 if (backup_p) 206 backup_p->backup_redirected_cnt++; 207 rcu_assign_pointer(p->backup_port, backup_p); 208 209 return 0; 210 } 211 212 static void nbp_backup_clear(struct net_bridge_port *p) 213 { 214 nbp_backup_change(p, NULL); 215 if (p->backup_redirected_cnt) { 216 struct net_bridge_port *cur_p; 217 218 list_for_each_entry(cur_p, &p->br->port_list, list) { 219 struct net_bridge_port *backup_p; 220 221 backup_p = rtnl_dereference(cur_p->backup_port); 222 if (backup_p == p) 223 nbp_backup_change(cur_p, NULL); 224 } 225 } 226 227 WARN_ON(rcu_access_pointer(p->backup_port) || p->backup_redirected_cnt); 228 } 229 230 static void nbp_update_port_count(struct net_bridge *br) 231 { 232 struct net_bridge_port *p; 233 u32 cnt = 0; 234 235 list_for_each_entry(p, &br->port_list, list) { 236 if (br_auto_port(p)) 237 cnt++; 238 } 239 if (br->auto_cnt != cnt) { 240 br->auto_cnt = cnt; 241 br_manage_promisc(br); 242 } 243 } 244 245 static void nbp_delete_promisc(struct net_bridge_port *p) 246 { 247 /* If port is currently promiscuous, unset promiscuity. 248 * Otherwise, it is a static port so remove all addresses 249 * from it. 250 */ 251 dev_set_allmulti(p->dev, -1); 252 if (br_promisc_port(p)) 253 dev_set_promiscuity(p->dev, -1); 254 else 255 br_fdb_unsync_static(p->br, p); 256 } 257 258 static void release_nbp(struct kobject *kobj) 259 { 260 struct net_bridge_port *p 261 = container_of(kobj, struct net_bridge_port, kobj); 262 kfree(p); 263 } 264 265 static void brport_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid) 266 { 267 struct net_bridge_port *p = kobj_to_brport(kobj); 268 269 net_ns_get_ownership(dev_net(p->dev), uid, gid); 270 } 271 272 static const struct kobj_type brport_ktype = { 273 #ifdef CONFIG_SYSFS 274 .sysfs_ops = &brport_sysfs_ops, 275 #endif 276 .release = release_nbp, 277 .get_ownership = brport_get_ownership, 278 }; 279 280 static void destroy_nbp(struct net_bridge_port *p) 281 { 282 struct net_device *dev = p->dev; 283 284 p->br = NULL; 285 p->dev = NULL; 286 netdev_put(dev, &p->dev_tracker); 287 288 kobject_put(&p->kobj); 289 } 290 291 static void destroy_nbp_rcu(struct rcu_head *head) 292 { 293 struct net_bridge_port *p = 294 container_of(head, struct net_bridge_port, rcu); 295 destroy_nbp(p); 296 } 297 298 static unsigned get_max_headroom(struct net_bridge *br) 299 { 300 unsigned max_headroom = 0; 301 struct net_bridge_port *p; 302 303 list_for_each_entry(p, &br->port_list, list) { 304 unsigned dev_headroom = netdev_get_fwd_headroom(p->dev); 305 306 if (dev_headroom > max_headroom) 307 max_headroom = dev_headroom; 308 } 309 310 return max_headroom; 311 } 312 313 static void update_headroom(struct net_bridge *br, int new_hr) 314 { 315 struct net_bridge_port *p; 316 317 list_for_each_entry(p, &br->port_list, list) 318 netdev_set_rx_headroom(p->dev, new_hr); 319 320 br->dev->needed_headroom = new_hr; 321 } 322 323 /* Delete port(interface) from bridge is done in two steps. 324 * via RCU. First step, marks device as down. That deletes 325 * all the timers and stops new packets from flowing through. 326 * 327 * Final cleanup doesn't occur until after all CPU's finished 328 * processing packets. 329 * 330 * Protected from multiple admin operations by RTNL mutex 331 */ 332 static void del_nbp(struct net_bridge_port *p) 333 { 334 struct net_bridge *br = p->br; 335 struct net_device *dev = p->dev; 336 337 sysfs_remove_link(br->ifobj, p->dev->name); 338 339 nbp_delete_promisc(p); 340 341 spin_lock_bh(&br->lock); 342 br_stp_disable_port(p); 343 spin_unlock_bh(&br->lock); 344 345 br_mrp_port_del(br, p); 346 br_cfm_port_del(br, p); 347 348 br_ifinfo_notify(RTM_DELLINK, NULL, p); 349 350 list_del_rcu(&p->list); 351 if (netdev_get_fwd_headroom(dev) == br->dev->needed_headroom) 352 update_headroom(br, get_max_headroom(br)); 353 netdev_reset_rx_headroom(dev); 354 355 nbp_vlan_flush(p); 356 br_fdb_delete_by_port(br, p, 0, 1); 357 switchdev_deferred_process(); 358 nbp_backup_clear(p); 359 360 nbp_update_port_count(br); 361 362 netdev_upper_dev_unlink(dev, br->dev); 363 364 dev->priv_flags &= ~IFF_BRIDGE_PORT; 365 366 netdev_rx_handler_unregister(dev); 367 368 br_multicast_del_port(p); 369 370 kobject_uevent(&p->kobj, KOBJ_REMOVE); 371 kobject_del(&p->kobj); 372 373 br_netpoll_disable(p); 374 375 call_rcu(&p->rcu, destroy_nbp_rcu); 376 } 377 378 /* Delete bridge device */ 379 void br_dev_delete(struct net_device *dev, struct list_head *head) 380 { 381 struct net_bridge *br = netdev_priv(dev); 382 struct net_bridge_port *p, *n; 383 384 list_for_each_entry_safe(p, n, &br->port_list, list) { 385 del_nbp(p); 386 } 387 388 br_recalculate_neigh_suppress_enabled(br); 389 390 br_fdb_delete_by_port(br, NULL, 0, 1); 391 392 cancel_delayed_work_sync(&br->gc_work); 393 394 br_sysfs_delbr(br->dev); 395 unregister_netdevice_queue(br->dev, head); 396 } 397 398 /* find an available port number */ 399 static int find_portno(struct net_bridge *br) 400 { 401 int index; 402 struct net_bridge_port *p; 403 unsigned long *inuse; 404 405 inuse = bitmap_zalloc(BR_MAX_PORTS, GFP_KERNEL); 406 if (!inuse) 407 return -ENOMEM; 408 409 __set_bit(0, inuse); /* zero is reserved */ 410 list_for_each_entry(p, &br->port_list, list) 411 __set_bit(p->port_no, inuse); 412 413 index = find_first_zero_bit(inuse, BR_MAX_PORTS); 414 bitmap_free(inuse); 415 416 return (index >= BR_MAX_PORTS) ? -EXFULL : index; 417 } 418 419 /* called with RTNL but without bridge lock */ 420 static struct net_bridge_port *new_nbp(struct net_bridge *br, 421 struct net_device *dev) 422 { 423 struct net_bridge_port *p; 424 int index, err; 425 426 index = find_portno(br); 427 if (index < 0) 428 return ERR_PTR(index); 429 430 p = kzalloc(sizeof(*p), GFP_KERNEL); 431 if (p == NULL) 432 return ERR_PTR(-ENOMEM); 433 434 p->br = br; 435 netdev_hold(dev, &p->dev_tracker, GFP_KERNEL); 436 p->dev = dev; 437 p->path_cost = port_cost(dev); 438 p->priority = 0x8000 >> BR_PORT_BITS; 439 p->port_no = index; 440 p->flags = BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD | BR_BCAST_FLOOD; 441 br_init_port(p); 442 br_set_state(p, BR_STATE_DISABLED); 443 br_stp_port_timer_init(p); 444 err = br_multicast_add_port(p); 445 if (err) { 446 netdev_put(dev, &p->dev_tracker); 447 kfree(p); 448 p = ERR_PTR(err); 449 } 450 451 return p; 452 } 453 454 int br_add_bridge(struct net *net, const char *name) 455 { 456 struct net_device *dev; 457 int res; 458 459 dev = alloc_netdev(sizeof(struct net_bridge), name, NET_NAME_UNKNOWN, 460 br_dev_setup); 461 462 if (!dev) 463 return -ENOMEM; 464 465 dev_net_set(dev, net); 466 dev->rtnl_link_ops = &br_link_ops; 467 468 res = register_netdevice(dev); 469 if (res) 470 free_netdev(dev); 471 return res; 472 } 473 474 int br_del_bridge(struct net *net, const char *name) 475 { 476 struct net_device *dev; 477 int ret = 0; 478 479 dev = __dev_get_by_name(net, name); 480 if (dev == NULL) 481 ret = -ENXIO; /* Could not find device */ 482 483 else if (!netif_is_bridge_master(dev)) { 484 /* Attempt to delete non bridge device! */ 485 ret = -EPERM; 486 } 487 488 else if (dev->flags & IFF_UP) { 489 /* Not shutdown yet. */ 490 ret = -EBUSY; 491 } 492 493 else 494 br_dev_delete(dev, NULL); 495 496 return ret; 497 } 498 499 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */ 500 static int br_mtu_min(const struct net_bridge *br) 501 { 502 const struct net_bridge_port *p; 503 int ret_mtu = 0; 504 505 list_for_each_entry(p, &br->port_list, list) 506 if (!ret_mtu || ret_mtu > p->dev->mtu) 507 ret_mtu = p->dev->mtu; 508 509 return ret_mtu ? ret_mtu : ETH_DATA_LEN; 510 } 511 512 void br_mtu_auto_adjust(struct net_bridge *br) 513 { 514 ASSERT_RTNL(); 515 516 /* if the bridge MTU was manually configured don't mess with it */ 517 if (br_opt_get(br, BROPT_MTU_SET_BY_USER)) 518 return; 519 520 /* change to the minimum MTU and clear the flag which was set by 521 * the bridge ndo_change_mtu callback 522 */ 523 dev_set_mtu(br->dev, br_mtu_min(br)); 524 br_opt_toggle(br, BROPT_MTU_SET_BY_USER, false); 525 } 526 527 static void br_set_gso_limits(struct net_bridge *br) 528 { 529 unsigned int tso_max_size = TSO_MAX_SIZE; 530 const struct net_bridge_port *p; 531 u16 tso_max_segs = TSO_MAX_SEGS; 532 533 list_for_each_entry(p, &br->port_list, list) { 534 tso_max_size = min(tso_max_size, p->dev->tso_max_size); 535 tso_max_segs = min(tso_max_segs, p->dev->tso_max_segs); 536 } 537 netif_set_tso_max_size(br->dev, tso_max_size); 538 netif_set_tso_max_segs(br->dev, tso_max_segs); 539 } 540 541 /* 542 * Recomputes features using slave's features 543 */ 544 netdev_features_t br_features_recompute(struct net_bridge *br, 545 netdev_features_t features) 546 { 547 struct net_bridge_port *p; 548 netdev_features_t mask; 549 550 if (list_empty(&br->port_list)) 551 return features; 552 553 mask = features; 554 features &= ~NETIF_F_ONE_FOR_ALL; 555 556 list_for_each_entry(p, &br->port_list, list) { 557 features = netdev_increment_features(features, 558 p->dev->features, mask); 559 } 560 features = netdev_add_tso_features(features, mask); 561 562 return features; 563 } 564 565 /* called with RTNL */ 566 int br_add_if(struct net_bridge *br, struct net_device *dev, 567 struct netlink_ext_ack *extack) 568 { 569 struct net_bridge_port *p; 570 int err = 0; 571 unsigned br_hr, dev_hr; 572 bool changed_addr, fdb_synced = false; 573 574 /* Don't allow bridging non-ethernet like devices. */ 575 if ((dev->flags & IFF_LOOPBACK) || 576 dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN || 577 !is_valid_ether_addr(dev->dev_addr)) 578 return -EINVAL; 579 580 /* No bridging of bridges */ 581 if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit) { 582 NL_SET_ERR_MSG(extack, 583 "Can not enslave a bridge to a bridge"); 584 return -ELOOP; 585 } 586 587 /* Device has master upper dev */ 588 if (netdev_master_upper_dev_get(dev)) 589 return -EBUSY; 590 591 /* No bridging devices that dislike that (e.g. wireless) */ 592 if (dev->priv_flags & IFF_DONT_BRIDGE) { 593 NL_SET_ERR_MSG(extack, 594 "Device does not allow enslaving to a bridge"); 595 return -EOPNOTSUPP; 596 } 597 598 p = new_nbp(br, dev); 599 if (IS_ERR(p)) 600 return PTR_ERR(p); 601 602 call_netdevice_notifiers(NETDEV_JOIN, dev); 603 604 err = dev_set_allmulti(dev, 1); 605 if (err) { 606 br_multicast_del_port(p); 607 netdev_put(dev, &p->dev_tracker); 608 kfree(p); /* kobject not yet init'd, manually free */ 609 goto err1; 610 } 611 612 err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj), 613 SYSFS_BRIDGE_PORT_ATTR); 614 if (err) 615 goto err2; 616 617 err = br_sysfs_addif(p); 618 if (err) 619 goto err2; 620 621 err = br_netpoll_enable(p); 622 if (err) 623 goto err3; 624 625 err = netdev_rx_handler_register(dev, br_get_rx_handler(dev), p); 626 if (err) 627 goto err4; 628 629 dev->priv_flags |= IFF_BRIDGE_PORT; 630 631 err = netdev_master_upper_dev_link(dev, br->dev, NULL, NULL, extack); 632 if (err) 633 goto err5; 634 635 dev_disable_lro(dev); 636 637 list_add_rcu(&p->list, &br->port_list); 638 639 nbp_update_port_count(br); 640 if (!br_promisc_port(p) && (p->dev->priv_flags & IFF_UNICAST_FLT)) { 641 /* When updating the port count we also update all ports' 642 * promiscuous mode. 643 * A port leaving promiscuous mode normally gets the bridge's 644 * fdb synced to the unicast filter (if supported), however, 645 * `br_port_clear_promisc` does not distinguish between 646 * non-promiscuous ports and *new* ports, so we need to 647 * sync explicitly here. 648 */ 649 fdb_synced = br_fdb_sync_static(br, p) == 0; 650 if (!fdb_synced) 651 netdev_err(dev, "failed to sync bridge static fdb addresses to this port\n"); 652 } 653 654 netdev_update_features(br->dev); 655 656 br_hr = br->dev->needed_headroom; 657 dev_hr = netdev_get_fwd_headroom(dev); 658 if (br_hr < dev_hr) 659 update_headroom(br, dev_hr); 660 else 661 netdev_set_rx_headroom(dev, br_hr); 662 663 if (br_fdb_add_local(br, p, dev->dev_addr, 0)) 664 netdev_err(dev, "failed insert local address bridge forwarding table\n"); 665 666 if (br->dev->addr_assign_type != NET_ADDR_SET) { 667 /* Ask for permission to use this MAC address now, even if we 668 * don't end up choosing it below. 669 */ 670 err = dev_pre_changeaddr_notify(br->dev, dev->dev_addr, extack); 671 if (err) 672 goto err6; 673 } 674 675 err = nbp_vlan_init(p, extack); 676 if (err) { 677 netdev_err(dev, "failed to initialize vlan filtering on this port\n"); 678 goto err6; 679 } 680 681 spin_lock_bh(&br->lock); 682 changed_addr = br_stp_recalculate_bridge_id(br); 683 684 if (netif_running(dev) && netif_oper_up(dev) && 685 (br->dev->flags & IFF_UP)) 686 br_stp_enable_port(p); 687 spin_unlock_bh(&br->lock); 688 689 br_ifinfo_notify(RTM_NEWLINK, NULL, p); 690 691 if (changed_addr) 692 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev); 693 694 br_mtu_auto_adjust(br); 695 br_set_gso_limits(br); 696 697 kobject_uevent(&p->kobj, KOBJ_ADD); 698 699 return 0; 700 701 err6: 702 if (fdb_synced) 703 br_fdb_unsync_static(br, p); 704 list_del_rcu(&p->list); 705 br_fdb_delete_by_port(br, p, 0, 1); 706 nbp_update_port_count(br); 707 netdev_upper_dev_unlink(dev, br->dev); 708 err5: 709 dev->priv_flags &= ~IFF_BRIDGE_PORT; 710 netdev_rx_handler_unregister(dev); 711 err4: 712 br_netpoll_disable(p); 713 err3: 714 sysfs_remove_link(br->ifobj, p->dev->name); 715 err2: 716 br_multicast_del_port(p); 717 netdev_put(dev, &p->dev_tracker); 718 kobject_put(&p->kobj); 719 dev_set_allmulti(dev, -1); 720 err1: 721 return err; 722 } 723 724 /* called with RTNL */ 725 int br_del_if(struct net_bridge *br, struct net_device *dev) 726 { 727 struct net_bridge_port *p; 728 bool changed_addr; 729 730 p = br_port_get_rtnl(dev); 731 if (!p || p->br != br) 732 return -EINVAL; 733 734 /* Since more than one interface can be attached to a bridge, 735 * there still maybe an alternate path for netconsole to use; 736 * therefore there is no reason for a NETDEV_RELEASE event. 737 */ 738 del_nbp(p); 739 740 br_mtu_auto_adjust(br); 741 br_set_gso_limits(br); 742 743 spin_lock_bh(&br->lock); 744 changed_addr = br_stp_recalculate_bridge_id(br); 745 spin_unlock_bh(&br->lock); 746 747 if (changed_addr) 748 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev); 749 750 netdev_update_features(br->dev); 751 752 return 0; 753 } 754 755 void br_port_flags_change(struct net_bridge_port *p, unsigned long mask) 756 { 757 struct net_bridge *br = p->br; 758 759 if (mask & BR_AUTO_MASK) 760 nbp_update_port_count(br); 761 762 if (mask & (BR_NEIGH_SUPPRESS | BR_NEIGH_VLAN_SUPPRESS)) 763 br_recalculate_neigh_suppress_enabled(br); 764 } 765 766 bool br_port_flag_is_set(const struct net_device *dev, unsigned long flag) 767 { 768 struct net_bridge_port *p; 769 770 p = br_port_get_rtnl_rcu(dev); 771 if (!p) 772 return false; 773 774 return p->flags & flag; 775 } 776 EXPORT_SYMBOL_GPL(br_port_flag_is_set); 777