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