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