net/bridge/br_if.c

   1 /*
   2  *      Userspace interface
   3  *      Linux ethernet bridge
   4  *
   5  *      Authors:
   6  *      Lennert Buytenhek               <buytenh@gnu.org>
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/etherdevice.h>
  17 #include <linux/netpoll.h>
  18 #include <linux/ethtool.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/rtnetlink.h>
  23 #include <linux/if_ether.h>
  24 #include <linux/slab.h>
  25 #include <net/dsa.h>
  26 #include <net/sock.h>
  27 #include <linux/if_vlan.h>
  28 #include <net/switchdev.h>
  29
  30 #include "br_private.h"
  31
  32 /*
  33  * Determine initial path cost based on speed.
  34  * using recommendations from 802.1d standard
  35  *
  36  * Since driver might sleep need to not be holding any locks.
  37  */
  38 static int port_cost(struct net_device *dev)
  39 {
  40         struct ethtool_link_ksettings ecmd;
  41
  42         if (!__ethtool_get_link_ksettings(dev, &ecmd)) {
  43                 switch (ecmd.base.speed) {
  44                 case SPEED_10000:
  45                         return 2;
  46                 case SPEED_1000:
  47                         return 4;
  48                 case SPEED_100:
  49                         return 19;
  50                 case SPEED_10:
  51                         return 100;
  52                 }
  53         }
  54
  55         /* Old silly heuristics based on name */
  56         if (!strncmp(dev->name, "lec", 3))
  57                 return 7;
  58
  59         if (!strncmp(dev->name, "plip", 4))
  60                 return 2500;
  61
  62         return 100;     /* assume old 10Mbps */
  63 }
  64
  65
  66 /* Check for port carrier transitions. */
  67 void br_port_carrier_check(struct net_bridge_port *p)
  68 {
  69         struct net_device *dev = p->dev;
  70         struct net_bridge *br = p->br;
  71
  72         if (!(p->flags & BR_ADMIN_COST) &&
  73             netif_running(dev) && netif_oper_up(dev))
  74                 p->path_cost = port_cost(dev);
  75
  76         if (!netif_running(br->dev))
  77                 return;
  78
  79         spin_lock_bh(&br->lock);
  80         if (netif_running(dev) && netif_oper_up(dev)) {
  81                 if (p->state == BR_STATE_DISABLED)
  82                         br_stp_enable_port(p);
  83         } else {
  84                 if (p->state != BR_STATE_DISABLED)
  85                         br_stp_disable_port(p);
  86         }
  87         spin_unlock_bh(&br->lock);
  88 }
  89
  90 static void br_port_set_promisc(struct net_bridge_port *p)
  91 {
  92         int err = 0;
  93
  94         if (br_promisc_port(p))
  95                 return;
  96
  97         err = dev_set_promiscuity(p->dev, 1);
  98         if (err)
  99                 return;
 100
 101         br_fdb_unsync_static(p->br, p);
 102         p->flags |= BR_PROMISC;
 103 }
 104
 105 static void br_port_clear_promisc(struct net_bridge_port *p)
 106 {
 107         int err;
 108
 109         /* Check if the port is already non-promisc or if it doesn't
 110          * support UNICAST filtering.  Without unicast filtering support
 111          * we'll end up re-enabling promisc mode anyway, so just check for
 112          * it here.
 113          */
 114         if (!br_promisc_port(p) || !(p->dev->priv_flags & IFF_UNICAST_FLT))
 115                 return;
 116
 117         /* Since we'll be clearing the promisc mode, program the port
 118          * first so that we don't have interruption in traffic.
 119          */
 120         err = br_fdb_sync_static(p->br, p);
 121         if (err)
 122                 return;
 123
 124         dev_set_promiscuity(p->dev, -1);
 125         p->flags &= ~BR_PROMISC;
 126 }
 127
 128 /* When a port is added or removed or when certain port flags
 129  * change, this function is called to automatically manage
 130  * promiscuity setting of all the bridge ports.  We are always called
 131  * under RTNL so can skip using rcu primitives.
 132  */
 133 void br_manage_promisc(struct net_bridge *br)
 134 {
 135         struct net_bridge_port *p;
 136         bool set_all = false;
 137
 138         /* If vlan filtering is disabled or bridge interface is placed
 139          * into promiscuous mode, place all ports in promiscuous mode.
 140          */
 141         if ((br->dev->flags & IFF_PROMISC) || !br_vlan_enabled(br))
 142                 set_all = true;
 143
 144         list_for_each_entry(p, &br->port_list, list) {
 145                 if (set_all) {
 146                         br_port_set_promisc(p);
 147                 } else {
 148                         /* If the number of auto-ports is <= 1, then all other
 149                          * ports will have their output configuration
 150                          * statically specified through fdbs.  Since ingress
 151                          * on the auto-port becomes forwarding/egress to other
 152                          * ports and egress configuration is statically known,
 153                          * we can say that ingress configuration of the
 154                          * auto-port is also statically known.
 155                          * This lets us disable promiscuous mode and write
 156                          * this config to hw.
 157                          */
 158                         if (br->auto_cnt == 0 ||
 159                             (br->auto_cnt == 1 && br_auto_port(p)))
 160                                 br_port_clear_promisc(p);
 161                         else
 162                                 br_port_set_promisc(p);
 163                 }
 164         }
 165 }
 166
 167 static void nbp_update_port_count(struct net_bridge *br)
 168 {
 169         struct net_bridge_port *p;
 170         u32 cnt = 0;
 171
 172         list_for_each_entry(p, &br->port_list, list) {
 173                 if (br_auto_port(p))
 174                         cnt++;
 175         }
 176         if (br->auto_cnt != cnt) {
 177                 br->auto_cnt = cnt;
 178                 br_manage_promisc(br);
 179         }
 180 }
 181
 182 static void nbp_delete_promisc(struct net_bridge_port *p)
 183 {
 184         /* If port is currently promiscuous, unset promiscuity.
 185          * Otherwise, it is a static port so remove all addresses
 186          * from it.
 187          */
 188         dev_set_allmulti(p->dev, -1);
 189         if (br_promisc_port(p))
 190                 dev_set_promiscuity(p->dev, -1);
 191         else
 192                 br_fdb_unsync_static(p->br, p);
 193 }
 194
 195 static void release_nbp(struct kobject *kobj)
 196 {
 197         struct net_bridge_port *p
 198                 = container_of(kobj, struct net_bridge_port, kobj);
 199         kfree(p);
 200 }
 201
 202 static struct kobj_type brport_ktype = {
 203 #ifdef CONFIG_SYSFS
 204         .sysfs_ops = &brport_sysfs_ops,
 205 #endif
 206         .release = release_nbp,
 207 };
 208
 209 static void destroy_nbp(struct net_bridge_port *p)
 210 {
 211         struct net_device *dev = p->dev;
 212
 213         p->br = NULL;
 214         p->dev = NULL;
 215         dev_put(dev);
 216
 217         kobject_put(&p->kobj);
 218 }
 219
 220 static void destroy_nbp_rcu(struct rcu_head *head)
 221 {
 222         struct net_bridge_port *p =
 223                         container_of(head, struct net_bridge_port, rcu);
 224         destroy_nbp(p);
 225 }
 226
 227 static unsigned get_max_headroom(struct net_bridge *br)
 228 {
 229         unsigned max_headroom = 0;
 230         struct net_bridge_port *p;
 231
 232         list_for_each_entry(p, &br->port_list, list) {
 233                 unsigned dev_headroom = netdev_get_fwd_headroom(p->dev);
 234
 235                 if (dev_headroom > max_headroom)
 236                         max_headroom = dev_headroom;
 237         }
 238
 239         return max_headroom;
 240 }
 241
 242 static void update_headroom(struct net_bridge *br, int new_hr)
 243 {
 244         struct net_bridge_port *p;
 245
 246         list_for_each_entry(p, &br->port_list, list)
 247                 netdev_set_rx_headroom(p->dev, new_hr);
 248
 249         br->dev->needed_headroom = new_hr;
 250 }
 251
 252 /* Delete port(interface) from bridge is done in two steps.
 253  * via RCU. First step, marks device as down. That deletes
 254  * all the timers and stops new packets from flowing through.
 255  *
 256  * Final cleanup doesn't occur until after all CPU's finished
 257  * processing packets.
 258  *
 259  * Protected from multiple admin operations by RTNL mutex
 260  */
 261 static void del_nbp(struct net_bridge_port *p)
 262 {
 263         struct net_bridge *br = p->br;
 264         struct net_device *dev = p->dev;
 265
 266         sysfs_remove_link(br->ifobj, p->dev->name);
 267
 268         nbp_delete_promisc(p);
 269
 270         spin_lock_bh(&br->lock);
 271         br_stp_disable_port(p);
 272         spin_unlock_bh(&br->lock);
 273
 274         br_ifinfo_notify(RTM_DELLINK, p);
 275
 276         list_del_rcu(&p->list);
 277         if (netdev_get_fwd_headroom(dev) == br->dev->needed_headroom)
 278                 update_headroom(br, get_max_headroom(br));
 279         netdev_reset_rx_headroom(dev);
 280
 281         nbp_vlan_flush(p);
 282         br_fdb_delete_by_port(br, p, 0, 1);
 283         switchdev_deferred_process();
 284
 285         nbp_update_port_count(br);
 286
 287         netdev_upper_dev_unlink(dev, br->dev);
 288
 289         dev->priv_flags &= ~IFF_BRIDGE_PORT;
 290
 291         netdev_rx_handler_unregister(dev);
 292
 293         br_multicast_del_port(p);
 294
 295         kobject_uevent(&p->kobj, KOBJ_REMOVE);
 296         kobject_del(&p->kobj);
 297
 298         br_netpoll_disable(p);
 299
 300         call_rcu(&p->rcu, destroy_nbp_rcu);
 301 }
 302
 303 /* Delete bridge device */
 304 void br_dev_delete(struct net_device *dev, struct list_head *head)
 305 {
 306         struct net_bridge *br = netdev_priv(dev);
 307         struct net_bridge_port *p, *n;
 308
 309         list_for_each_entry_safe(p, n, &br->port_list, list) {
 310                 del_nbp(p);
 311         }
 312
 313         br_fdb_delete_by_port(br, NULL, 0, 1);
 314
 315         br_vlan_flush(br);
 316         br_multicast_dev_del(br);
 317         cancel_delayed_work_sync(&br->gc_work);
 318
 319         br_sysfs_delbr(br->dev);
 320         unregister_netdevice_queue(br->dev, head);
 321 }
 322
 323 /* find an available port number */
 324 static int find_portno(struct net_bridge *br)
 325 {
 326         int index;
 327         struct net_bridge_port *p;
 328         unsigned long *inuse;
 329
 330         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
 331                         GFP_KERNEL);
 332         if (!inuse)
 333                 return -ENOMEM;
 334
 335         set_bit(0, inuse);      /* zero is reserved */
 336         list_for_each_entry(p, &br->port_list, list) {
 337                 set_bit(p->port_no, inuse);
 338         }
 339         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 340         kfree(inuse);
 341
 342         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
 343 }
 344
 345 /* called with RTNL but without bridge lock */
 346 static struct net_bridge_port *new_nbp(struct net_bridge *br,
 347                                        struct net_device *dev)
 348 {
 349         struct net_bridge_port *p;
 350         int index, err;
 351
 352         index = find_portno(br);
 353         if (index < 0)
 354                 return ERR_PTR(index);
 355
 356         p = kzalloc(sizeof(*p), GFP_KERNEL);
 357         if (p == NULL)
 358                 return ERR_PTR(-ENOMEM);
 359
 360         p->br = br;
 361         dev_hold(dev);
 362         p->dev = dev;
 363         p->path_cost = port_cost(dev);
 364         p->priority = 0x8000 >> BR_PORT_BITS;
 365         p->port_no = index;
 366         p->flags = BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD;
 367         br_init_port(p);
 368         br_set_state(p, BR_STATE_DISABLED);
 369         br_stp_port_timer_init(p);
 370         err = br_multicast_add_port(p);
 371         if (err) {
 372                 dev_put(dev);
 373                 kfree(p);
 374                 p = ERR_PTR(err);
 375         }
 376
 377         return p;
 378 }
 379
 380 int br_add_bridge(struct net *net, const char *name)
 381 {
 382         struct net_device *dev;
 383         int res;
 384
 385         dev = alloc_netdev(sizeof(struct net_bridge), name, NET_NAME_UNKNOWN,
 386                            br_dev_setup);
 387
 388         if (!dev)
 389                 return -ENOMEM;
 390
 391         dev_net_set(dev, net);
 392         dev->rtnl_link_ops = &br_link_ops;
 393
 394         res = register_netdev(dev);
 395         if (res)
 396                 free_netdev(dev);
 397         return res;
 398 }
 399
 400 int br_del_bridge(struct net *net, const char *name)
 401 {
 402         struct net_device *dev;
 403         int ret = 0;
 404
 405         rtnl_lock();
 406         dev = __dev_get_by_name(net, name);
 407         if (dev == NULL)
 408                 ret =  -ENXIO;  /* Could not find device */
 409
 410         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
 411                 /* Attempt to delete non bridge device! */
 412                 ret = -EPERM;
 413         }
 414
 415         else if (dev->flags & IFF_UP) {
 416                 /* Not shutdown yet. */
 417                 ret = -EBUSY;
 418         }
 419
 420         else
 421                 br_dev_delete(dev, NULL);
 422
 423         rtnl_unlock();
 424         return ret;
 425 }
 426
 427 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
 428 int br_min_mtu(const struct net_bridge *br)
 429 {
 430         const struct net_bridge_port *p;
 431         int mtu = 0;
 432
 433         ASSERT_RTNL();
 434
 435         if (list_empty(&br->port_list))
 436                 mtu = ETH_DATA_LEN;
 437         else {
 438                 list_for_each_entry(p, &br->port_list, list) {
 439                         if (!mtu  || p->dev->mtu < mtu)
 440                                 mtu = p->dev->mtu;
 441                 }
 442         }
 443         return mtu;
 444 }
 445
 446 static void br_set_gso_limits(struct net_bridge *br)
 447 {
 448         unsigned int gso_max_size = GSO_MAX_SIZE;
 449         u16 gso_max_segs = GSO_MAX_SEGS;
 450         const struct net_bridge_port *p;
 451
 452         list_for_each_entry(p, &br->port_list, list) {
 453                 gso_max_size = min(gso_max_size, p->dev->gso_max_size);
 454                 gso_max_segs = min(gso_max_segs, p->dev->gso_max_segs);
 455         }
 456         br->dev->gso_max_size = gso_max_size;
 457         br->dev->gso_max_segs = gso_max_segs;
 458 }
 459
 460 /*
 461  * Recomputes features using slave's features
 462  */
 463 netdev_features_t br_features_recompute(struct net_bridge *br,
 464         netdev_features_t features)
 465 {
 466         struct net_bridge_port *p;
 467         netdev_features_t mask;
 468
 469         if (list_empty(&br->port_list))
 470                 return features;
 471
 472         mask = features;
 473         features &= ~NETIF_F_ONE_FOR_ALL;
 474
 475         list_for_each_entry(p, &br->port_list, list) {
 476                 features = netdev_increment_features(features,
 477                                                      p->dev->features, mask);
 478         }
 479         features = netdev_add_tso_features(features, mask);
 480
 481         return features;
 482 }
 483
 484 /* called with RTNL */
 485 int br_add_if(struct net_bridge *br, struct net_device *dev)
 486 {
 487         struct net_bridge_port *p;
 488         int err = 0;
 489         unsigned br_hr, dev_hr;
 490         bool changed_addr;
 491
 492         /* Don't allow bridging non-ethernet like devices, or DSA-enabled
 493          * master network devices since the bridge layer rx_handler prevents
 494          * the DSA fake ethertype handler to be invoked, so we do not strip off
 495          * the DSA switch tag protocol header and the bridge layer just return
 496          * RX_HANDLER_CONSUMED, stopping RX processing for these frames.
 497          */
 498         if ((dev->flags & IFF_LOOPBACK) ||
 499             dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
 500             !is_valid_ether_addr(dev->dev_addr) ||
 501             netdev_uses_dsa(dev))
 502                 return -EINVAL;
 503
 504         /* No bridging of bridges */
 505         if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
 506                 return -ELOOP;
 507
 508         /* Device is already being bridged */
 509         if (br_port_exists(dev))
 510                 return -EBUSY;
 511
 512         /* No bridging devices that dislike that (e.g. wireless) */
 513         if (dev->priv_flags & IFF_DONT_BRIDGE)
 514                 return -EOPNOTSUPP;
 515
 516         p = new_nbp(br, dev);
 517         if (IS_ERR(p))
 518                 return PTR_ERR(p);
 519
 520         call_netdevice_notifiers(NETDEV_JOIN, dev);
 521
 522         err = dev_set_allmulti(dev, 1);
 523         if (err)
 524                 goto put_back;
 525
 526         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
 527                                    SYSFS_BRIDGE_PORT_ATTR);
 528         if (err)
 529                 goto err1;
 530
 531         err = br_sysfs_addif(p);
 532         if (err)
 533                 goto err2;
 534
 535         err = br_netpoll_enable(p);
 536         if (err)
 537                 goto err3;
 538
 539         err = netdev_rx_handler_register(dev, br_handle_frame, p);
 540         if (err)
 541                 goto err4;
 542
 543         dev->priv_flags |= IFF_BRIDGE_PORT;
 544
 545         err = netdev_master_upper_dev_link(dev, br->dev, NULL, NULL);
 546         if (err)
 547                 goto err5;
 548
 549         err = nbp_switchdev_mark_set(p);
 550         if (err)
 551                 goto err6;
 552
 553         dev_disable_lro(dev);
 554
 555         list_add_rcu(&p->list, &br->port_list);
 556
 557         nbp_update_port_count(br);
 558
 559         netdev_update_features(br->dev);
 560
 561         br_hr = br->dev->needed_headroom;
 562         dev_hr = netdev_get_fwd_headroom(dev);
 563         if (br_hr < dev_hr)
 564                 update_headroom(br, dev_hr);
 565         else
 566                 netdev_set_rx_headroom(dev, br_hr);
 567
 568         if (br_fdb_insert(br, p, dev->dev_addr, 0))
 569                 netdev_err(dev, "failed insert local address bridge forwarding table\n");
 570
 571         err = nbp_vlan_init(p);
 572         if (err) {
 573                 netdev_err(dev, "failed to initialize vlan filtering on this port\n");
 574                 goto err7;
 575         }
 576
 577         spin_lock_bh(&br->lock);
 578         changed_addr = br_stp_recalculate_bridge_id(br);
 579
 580         if (netif_running(dev) && netif_oper_up(dev) &&
 581             (br->dev->flags & IFF_UP))
 582                 br_stp_enable_port(p);
 583         spin_unlock_bh(&br->lock);
 584
 585         br_ifinfo_notify(RTM_NEWLINK, p);
 586
 587         if (changed_addr)
 588                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
 589
 590         dev_set_mtu(br->dev, br_min_mtu(br));
 591         br_set_gso_limits(br);
 592
 593         kobject_uevent(&p->kobj, KOBJ_ADD);
 594
 595         return 0;
 596
 597 err7:
 598         list_del_rcu(&p->list);
 599         br_fdb_delete_by_port(br, p, 0, 1);
 600         nbp_update_port_count(br);
 601 err6:
 602         netdev_upper_dev_unlink(dev, br->dev);
 603 err5:
 604         dev->priv_flags &= ~IFF_BRIDGE_PORT;
 605         netdev_rx_handler_unregister(dev);
 606 err4:
 607         br_netpoll_disable(p);
 608 err3:
 609         sysfs_remove_link(br->ifobj, p->dev->name);
 610 err2:
 611         kobject_put(&p->kobj);
 612         p = NULL; /* kobject_put frees */
 613 err1:
 614         dev_set_allmulti(dev, -1);
 615 put_back:
 616         dev_put(dev);
 617         kfree(p);
 618         return err;
 619 }
 620
 621 /* called with RTNL */
 622 int br_del_if(struct net_bridge *br, struct net_device *dev)
 623 {
 624         struct net_bridge_port *p;
 625         bool changed_addr;
 626
 627         p = br_port_get_rtnl(dev);
 628         if (!p || p->br != br)
 629                 return -EINVAL;
 630
 631         /* Since more than one interface can be attached to a bridge,
 632          * there still maybe an alternate path for netconsole to use;
 633          * therefore there is no reason for a NETDEV_RELEASE event.
 634          */
 635         del_nbp(p);
 636
 637         dev_set_mtu(br->dev, br_min_mtu(br));
 638         br_set_gso_limits(br);
 639
 640         spin_lock_bh(&br->lock);
 641         changed_addr = br_stp_recalculate_bridge_id(br);
 642         spin_unlock_bh(&br->lock);
 643
 644         if (changed_addr)
 645                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
 646
 647         netdev_update_features(br->dev);
 648
 649         return 0;
 650 }
 651
 652 void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
 653 {
 654         struct net_bridge *br = p->br;
 655
 656         if (mask & BR_AUTO_MASK)
 657                 nbp_update_port_count(br);
 658 }