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_link_ksettings ecmd;
  40
  41         if (!__ethtool_get_link_ksettings(dev, &ecmd)) {
  42                 switch (ecmd.base.speed) {
  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 static unsigned get_max_headroom(struct net_bridge *br)
 227 {
 228         unsigned max_headroom = 0;
 229         struct net_bridge_port *p;
 230
 231         list_for_each_entry(p, &br->port_list, list) {
 232                 unsigned dev_headroom = netdev_get_fwd_headroom(p->dev);
 233
 234                 if (dev_headroom > max_headroom)
 235                         max_headroom = dev_headroom;
 236         }
 237
 238         return max_headroom;
 239 }
 240
 241 static void update_headroom(struct net_bridge *br, int new_hr)
 242 {
 243         struct net_bridge_port *p;
 244
 245         list_for_each_entry(p, &br->port_list, list)
 246                 netdev_set_rx_headroom(p->dev, new_hr);
 247
 248         br->dev->needed_headroom = new_hr;
 249 }
 250
 251 /* Delete port(interface) from bridge is done in two steps.
 252  * via RCU. First step, marks device as down. That deletes
 253  * all the timers and stops new packets from flowing through.
 254  *
 255  * Final cleanup doesn't occur until after all CPU's finished
 256  * processing packets.
 257  *
 258  * Protected from multiple admin operations by RTNL mutex
 259  */
 260 static void del_nbp(struct net_bridge_port *p)
 261 {
 262         struct net_bridge *br = p->br;
 263         struct net_device *dev = p->dev;
 264
 265         sysfs_remove_link(br->ifobj, p->dev->name);
 266
 267         nbp_delete_promisc(p);
 268
 269         spin_lock_bh(&br->lock);
 270         br_stp_disable_port(p);
 271         spin_unlock_bh(&br->lock);
 272
 273         br_ifinfo_notify(RTM_DELLINK, p);
 274
 275         list_del_rcu(&p->list);
 276         if (netdev_get_fwd_headroom(dev) == br->dev->needed_headroom)
 277                 update_headroom(br, get_max_headroom(br));
 278         netdev_reset_rx_headroom(dev);
 279
 280         nbp_vlan_flush(p);
 281         br_fdb_delete_by_port(br, p, 0, 1);
 282         switchdev_deferred_process();
 283
 284         nbp_update_port_count(br);
 285
 286         netdev_upper_dev_unlink(dev, br->dev);
 287
 288         dev->priv_flags &= ~IFF_BRIDGE_PORT;
 289
 290         netdev_rx_handler_unregister(dev);
 291
 292         br_multicast_del_port(p);
 293
 294         kobject_uevent(&p->kobj, KOBJ_REMOVE);
 295         kobject_del(&p->kobj);
 296
 297         br_netpoll_disable(p);
 298
 299         call_rcu(&p->rcu, destroy_nbp_rcu);
 300 }
 301
 302 /* Delete bridge device */
 303 void br_dev_delete(struct net_device *dev, struct list_head *head)
 304 {
 305         struct net_bridge *br = netdev_priv(dev);
 306         struct net_bridge_port *p, *n;
 307
 308         list_for_each_entry_safe(p, n, &br->port_list, list) {
 309                 del_nbp(p);
 310         }
 311
 312         br_fdb_delete_by_port(br, NULL, 0, 1);
 313
 314         br_vlan_flush(br);
 315         br_multicast_dev_del(br);
 316         cancel_delayed_work_sync(&br->gc_work);
 317
 318         br_sysfs_delbr(br->dev);
 319         unregister_netdevice_queue(br->dev, head);
 320 }
 321
 322 /* find an available port number */
 323 static int find_portno(struct net_bridge *br)
 324 {
 325         int index;
 326         struct net_bridge_port *p;
 327         unsigned long *inuse;
 328
 329         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
 330                         GFP_KERNEL);
 331         if (!inuse)
 332                 return -ENOMEM;
 333
 334         set_bit(0, inuse);      /* zero is reserved */
 335         list_for_each_entry(p, &br->port_list, list) {
 336                 set_bit(p->port_no, inuse);
 337         }
 338         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 339         kfree(inuse);
 340
 341         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
 342 }
 343
 344 /* called with RTNL but without bridge lock */
 345 static struct net_bridge_port *new_nbp(struct net_bridge *br,
 346                                        struct net_device *dev)
 347 {
 348         struct net_bridge_port *p;
 349         int index, err;
 350
 351         index = find_portno(br);
 352         if (index < 0)
 353                 return ERR_PTR(index);
 354
 355         p = kzalloc(sizeof(*p), GFP_KERNEL);
 356         if (p == NULL)
 357                 return ERR_PTR(-ENOMEM);
 358
 359         p->br = br;
 360         dev_hold(dev);
 361         p->dev = dev;
 362         p->path_cost = port_cost(dev);
 363         p->priority = 0x8000 >> BR_PORT_BITS;
 364         p->port_no = index;
 365         p->flags = BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD;
 366         br_init_port(p);
 367         br_set_state(p, BR_STATE_DISABLED);
 368         br_stp_port_timer_init(p);
 369         err = br_multicast_add_port(p);
 370         if (err) {
 371                 dev_put(dev);
 372                 kfree(p);
 373                 p = ERR_PTR(err);
 374         }
 375
 376         return p;
 377 }
 378
 379 int br_add_bridge(struct net *net, const char *name)
 380 {
 381         struct net_device *dev;
 382         int res;
 383
 384         dev = alloc_netdev(sizeof(struct net_bridge), name, NET_NAME_UNKNOWN,
 385                            br_dev_setup);
 386
 387         if (!dev)
 388                 return -ENOMEM;
 389
 390         dev_net_set(dev, net);
 391         dev->rtnl_link_ops = &br_link_ops;
 392
 393         res = register_netdev(dev);
 394         if (res)
 395                 free_netdev(dev);
 396         return res;
 397 }
 398
 399 int br_del_bridge(struct net *net, const char *name)
 400 {
 401         struct net_device *dev;
 402         int ret = 0;
 403
 404         rtnl_lock();
 405         dev = __dev_get_by_name(net, name);
 406         if (dev == NULL)
 407                 ret =  -ENXIO;  /* Could not find device */
 408
 409         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
 410                 /* Attempt to delete non bridge device! */
 411                 ret = -EPERM;
 412         }
 413
 414         else if (dev->flags & IFF_UP) {
 415                 /* Not shutdown yet. */
 416                 ret = -EBUSY;
 417         }
 418
 419         else
 420                 br_dev_delete(dev, NULL);
 421
 422         rtnl_unlock();
 423         return ret;
 424 }
 425
 426 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
 427 int br_min_mtu(const struct net_bridge *br)
 428 {
 429         const struct net_bridge_port *p;
 430         int mtu = 0;
 431
 432         ASSERT_RTNL();
 433
 434         if (list_empty(&br->port_list))
 435                 mtu = ETH_DATA_LEN;
 436         else {
 437                 list_for_each_entry(p, &br->port_list, list) {
 438                         if (!mtu  || p->dev->mtu < mtu)
 439                                 mtu = p->dev->mtu;
 440                 }
 441         }
 442         return mtu;
 443 }
 444
 445 static void br_set_gso_limits(struct net_bridge *br)
 446 {
 447         unsigned int gso_max_size = GSO_MAX_SIZE;
 448         u16 gso_max_segs = GSO_MAX_SEGS;
 449         const struct net_bridge_port *p;
 450
 451         list_for_each_entry(p, &br->port_list, list) {
 452                 gso_max_size = min(gso_max_size, p->dev->gso_max_size);
 453                 gso_max_segs = min(gso_max_segs, p->dev->gso_max_segs);
 454         }
 455         br->dev->gso_max_size = gso_max_size;
 456         br->dev->gso_max_segs = gso_max_segs;
 457 }
 458
 459 /*
 460  * Recomputes features using slave's features
 461  */
 462 netdev_features_t br_features_recompute(struct net_bridge *br,
 463         netdev_features_t features)
 464 {
 465         struct net_bridge_port *p;
 466         netdev_features_t mask;
 467
 468         if (list_empty(&br->port_list))
 469                 return features;
 470
 471         mask = features;
 472         features &= ~NETIF_F_ONE_FOR_ALL;
 473
 474         list_for_each_entry(p, &br->port_list, list) {
 475                 features = netdev_increment_features(features,
 476                                                      p->dev->features, mask);
 477         }
 478         features = netdev_add_tso_features(features, mask);
 479
 480         return features;
 481 }
 482
 483 /* called with RTNL */
 484 int br_add_if(struct net_bridge *br, struct net_device *dev)
 485 {
 486         struct net_bridge_port *p;
 487         int err = 0;
 488         unsigned br_hr, dev_hr;
 489         bool changed_addr;
 490
 491         /* Don't allow bridging non-ethernet like devices, or DSA-enabled
 492          * master network devices since the bridge layer rx_handler prevents
 493          * the DSA fake ethertype handler to be invoked, so we do not strip off
 494          * the DSA switch tag protocol header and the bridge layer just return
 495          * RX_HANDLER_CONSUMED, stopping RX processing for these frames.
 496          */
 497         if ((dev->flags & IFF_LOOPBACK) ||
 498             dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
 499             !is_valid_ether_addr(dev->dev_addr) ||
 500             netdev_uses_dsa(dev))
 501                 return -EINVAL;
 502
 503         /* No bridging of bridges */
 504         if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
 505                 return -ELOOP;
 506
 507         /* Device is already being bridged */
 508         if (br_port_exists(dev))
 509                 return -EBUSY;
 510
 511         /* No bridging devices that dislike that (e.g. wireless) */
 512         if (dev->priv_flags & IFF_DONT_BRIDGE)
 513                 return -EOPNOTSUPP;
 514
 515         p = new_nbp(br, dev);
 516         if (IS_ERR(p))
 517                 return PTR_ERR(p);
 518
 519         call_netdevice_notifiers(NETDEV_JOIN, dev);
 520
 521         err = dev_set_allmulti(dev, 1);
 522         if (err)
 523                 goto put_back;
 524
 525         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
 526                                    SYSFS_BRIDGE_PORT_ATTR);
 527         if (err)
 528                 goto err1;
 529
 530         err = br_sysfs_addif(p);
 531         if (err)
 532                 goto err2;
 533
 534         err = br_netpoll_enable(p);
 535         if (err)
 536                 goto err3;
 537
 538         err = netdev_rx_handler_register(dev, br_handle_frame, p);
 539         if (err)
 540                 goto err4;
 541
 542         dev->priv_flags |= IFF_BRIDGE_PORT;
 543
 544         err = netdev_master_upper_dev_link(dev, br->dev, NULL, NULL);
 545         if (err)
 546                 goto err5;
 547
 548         err = nbp_switchdev_mark_set(p);
 549         if (err)
 550                 goto err6;
 551
 552         dev_disable_lro(dev);
 553
 554         list_add_rcu(&p->list, &br->port_list);
 555
 556         nbp_update_port_count(br);
 557
 558         netdev_update_features(br->dev);
 559
 560         br_hr = br->dev->needed_headroom;
 561         dev_hr = netdev_get_fwd_headroom(dev);
 562         if (br_hr < dev_hr)
 563                 update_headroom(br, dev_hr);
 564         else
 565                 netdev_set_rx_headroom(dev, br_hr);
 566
 567         if (br_fdb_insert(br, p, dev->dev_addr, 0))
 568                 netdev_err(dev, "failed insert local address bridge forwarding table\n");
 569
 570         err = nbp_vlan_init(p);
 571         if (err) {
 572                 netdev_err(dev, "failed to initialize vlan filtering on this port\n");
 573                 goto err7;
 574         }
 575
 576         spin_lock_bh(&br->lock);
 577         changed_addr = br_stp_recalculate_bridge_id(br);
 578
 579         if (netif_running(dev) && netif_oper_up(dev) &&
 580             (br->dev->flags & IFF_UP))
 581                 br_stp_enable_port(p);
 582         spin_unlock_bh(&br->lock);
 583
 584         br_ifinfo_notify(RTM_NEWLINK, p);
 585
 586         if (changed_addr)
 587                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
 588
 589         dev_set_mtu(br->dev, br_min_mtu(br));
 590         br_set_gso_limits(br);
 591
 592         kobject_uevent(&p->kobj, KOBJ_ADD);
 593
 594         return 0;
 595
 596 err7:
 597         list_del_rcu(&p->list);
 598         br_fdb_delete_by_port(br, p, 0, 1);
 599         nbp_update_port_count(br);
 600 err6:
 601         netdev_upper_dev_unlink(dev, br->dev);
 602 err5:
 603         dev->priv_flags &= ~IFF_BRIDGE_PORT;
 604         netdev_rx_handler_unregister(dev);
 605 err4:
 606         br_netpoll_disable(p);
 607 err3:
 608         sysfs_remove_link(br->ifobj, p->dev->name);
 609 err2:
 610         kobject_put(&p->kobj);
 611         p = NULL; /* kobject_put frees */
 612 err1:
 613         dev_set_allmulti(dev, -1);
 614 put_back:
 615         dev_put(dev);
 616         kfree(p);
 617         return err;
 618 }
 619
 620 /* called with RTNL */
 621 int br_del_if(struct net_bridge *br, struct net_device *dev)
 622 {
 623         struct net_bridge_port *p;
 624         bool changed_addr;
 625
 626         p = br_port_get_rtnl(dev);
 627         if (!p || p->br != br)
 628                 return -EINVAL;
 629
 630         /* Since more than one interface can be attached to a bridge,
 631          * there still maybe an alternate path for netconsole to use;
 632          * therefore there is no reason for a NETDEV_RELEASE event.
 633          */
 634         del_nbp(p);
 635
 636         dev_set_mtu(br->dev, br_min_mtu(br));
 637         br_set_gso_limits(br);
 638
 639         spin_lock_bh(&br->lock);
 640         changed_addr = br_stp_recalculate_bridge_id(br);
 641         spin_unlock_bh(&br->lock);
 642
 643         if (changed_addr)
 644                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
 645
 646         netdev_update_features(br->dev);
 647
 648         return 0;
 649 }
 650
 651 void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
 652 {
 653         struct net_bridge *br = p->br;
 654
 655         if (mask & BR_AUTO_MASK)
 656                 nbp_update_port_count(br);
 657 }