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/netpoll.h>
  17 #include <linux/ethtool.h>
  18 #include <linux/if_arp.h>
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <linux/rtnetlink.h>
  22 #include <linux/if_ether.h>
  23 #include <linux/slab.h>
  24 #include <net/sock.h>
  25
  26 #include "br_private.h"
  27
  28 /*
  29  * Determine initial path cost based on speed.
  30  * using recommendations from 802.1d standard
  31  *
  32  * Since driver might sleep need to not be holding any locks.
  33  */
  34 static int port_cost(struct net_device *dev)
  35 {
  36         if (dev->ethtool_ops && dev->ethtool_ops->get_settings) {
  37                 struct ethtool_cmd ecmd = { .cmd = ETHTOOL_GSET, };
  38
  39                 if (!dev->ethtool_ops->get_settings(dev, &ecmd)) {
  40                         switch(ecmd.speed) {
  41                         case SPEED_10000:
  42                                 return 2;
  43                         case SPEED_1000:
  44                                 return 4;
  45                         case SPEED_100:
  46                                 return 19;
  47                         case SPEED_10:
  48                                 return 100;
  49                         }
  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 transistions. */
  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 (netif_running(dev) && netif_carrier_ok(dev))
  71                 p->path_cost = port_cost(dev);
  72
  73         if (!netif_running(br->dev))
  74                 return;
  75
  76         spin_lock_bh(&br->lock);
  77         if (netif_running(dev) && netif_carrier_ok(dev)) {
  78                 if (p->state == BR_STATE_DISABLED)
  79                         br_stp_enable_port(p);
  80         } else {
  81                 if (p->state != BR_STATE_DISABLED)
  82                         br_stp_disable_port(p);
  83         }
  84         spin_unlock_bh(&br->lock);
  85 }
  86
  87 static void release_nbp(struct kobject *kobj)
  88 {
  89         struct net_bridge_port *p
  90                 = container_of(kobj, struct net_bridge_port, kobj);
  91         kfree(p);
  92 }
  93
  94 static struct kobj_type brport_ktype = {
  95 #ifdef CONFIG_SYSFS
  96         .sysfs_ops = &brport_sysfs_ops,
  97 #endif
  98         .release = release_nbp,
  99 };
 100
 101 static void destroy_nbp(struct net_bridge_port *p)
 102 {
 103         struct net_device *dev = p->dev;
 104
 105         p->br = NULL;
 106         p->dev = NULL;
 107         dev_put(dev);
 108
 109         kobject_put(&p->kobj);
 110 }
 111
 112 static void destroy_nbp_rcu(struct rcu_head *head)
 113 {
 114         struct net_bridge_port *p =
 115                         container_of(head, struct net_bridge_port, rcu);
 116         destroy_nbp(p);
 117 }
 118
 119 /* Delete port(interface) from bridge is done in two steps.
 120  * via RCU. First step, marks device as down. That deletes
 121  * all the timers and stops new packets from flowing through.
 122  *
 123  * Final cleanup doesn't occur until after all CPU's finished
 124  * processing packets.
 125  *
 126  * Protected from multiple admin operations by RTNL mutex
 127  */
 128 static void del_nbp(struct net_bridge_port *p)
 129 {
 130         struct net_bridge *br = p->br;
 131         struct net_device *dev = p->dev;
 132
 133         sysfs_remove_link(br->ifobj, p->dev->name);
 134
 135         dev_set_promiscuity(dev, -1);
 136
 137         spin_lock_bh(&br->lock);
 138         br_stp_disable_port(p);
 139         spin_unlock_bh(&br->lock);
 140
 141         br_ifinfo_notify(RTM_DELLINK, p);
 142
 143         br_fdb_delete_by_port(br, p, 1);
 144
 145         list_del_rcu(&p->list);
 146
 147         dev->priv_flags &= ~IFF_BRIDGE_PORT;
 148
 149         netdev_rx_handler_unregister(dev);
 150
 151         netdev_set_master(dev, NULL);
 152
 153         br_multicast_del_port(p);
 154
 155         kobject_uevent(&p->kobj, KOBJ_REMOVE);
 156         kobject_del(&p->kobj);
 157
 158         br_netpoll_disable(p);
 159
 160         call_rcu(&p->rcu, destroy_nbp_rcu);
 161 }
 162
 163 /* called with RTNL */
 164 static void del_br(struct net_bridge *br, struct list_head *head)
 165 {
 166         struct net_bridge_port *p, *n;
 167
 168         list_for_each_entry_safe(p, n, &br->port_list, list) {
 169                 del_nbp(p);
 170         }
 171
 172         del_timer_sync(&br->gc_timer);
 173
 174         br_sysfs_delbr(br->dev);
 175         unregister_netdevice_queue(br->dev, head);
 176 }
 177
 178 static struct net_device *new_bridge_dev(struct net *net, const char *name)
 179 {
 180         struct net_bridge *br;
 181         struct net_device *dev;
 182
 183         dev = alloc_netdev(sizeof(struct net_bridge), name,
 184                            br_dev_setup);
 185
 186         if (!dev)
 187                 return NULL;
 188         dev_net_set(dev, net);
 189
 190         br = netdev_priv(dev);
 191         br->dev = dev;
 192
 193         br->stats = alloc_percpu(struct br_cpu_netstats);
 194         if (!br->stats) {
 195                 free_netdev(dev);
 196                 return NULL;
 197         }
 198
 199         spin_lock_init(&br->lock);
 200         INIT_LIST_HEAD(&br->port_list);
 201         spin_lock_init(&br->hash_lock);
 202
 203         br->bridge_id.prio[0] = 0x80;
 204         br->bridge_id.prio[1] = 0x00;
 205
 206         memcpy(br->group_addr, br_group_address, ETH_ALEN);
 207
 208         br->feature_mask = dev->features;
 209         br->stp_enabled = BR_NO_STP;
 210         br->designated_root = br->bridge_id;
 211         br->root_path_cost = 0;
 212         br->root_port = 0;
 213         br->bridge_max_age = br->max_age = 20 * HZ;
 214         br->bridge_hello_time = br->hello_time = 2 * HZ;
 215         br->bridge_forward_delay = br->forward_delay = 15 * HZ;
 216         br->topology_change = 0;
 217         br->topology_change_detected = 0;
 218         br->ageing_time = 300 * HZ;
 219
 220         br_netfilter_rtable_init(br);
 221
 222         br_stp_timer_init(br);
 223         br_multicast_init(br);
 224
 225         return dev;
 226 }
 227
 228 /* find an available port number */
 229 static int find_portno(struct net_bridge *br)
 230 {
 231         int index;
 232         struct net_bridge_port *p;
 233         unsigned long *inuse;
 234
 235         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
 236                         GFP_KERNEL);
 237         if (!inuse)
 238                 return -ENOMEM;
 239
 240         set_bit(0, inuse);      /* zero is reserved */
 241         list_for_each_entry(p, &br->port_list, list) {
 242                 set_bit(p->port_no, inuse);
 243         }
 244         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 245         kfree(inuse);
 246
 247         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
 248 }
 249
 250 /* called with RTNL but without bridge lock */
 251 static struct net_bridge_port *new_nbp(struct net_bridge *br,
 252                                        struct net_device *dev)
 253 {
 254         int index;
 255         struct net_bridge_port *p;
 256
 257         index = find_portno(br);
 258         if (index < 0)
 259                 return ERR_PTR(index);
 260
 261         p = kzalloc(sizeof(*p), GFP_KERNEL);
 262         if (p == NULL)
 263                 return ERR_PTR(-ENOMEM);
 264
 265         p->br = br;
 266         dev_hold(dev);
 267         p->dev = dev;
 268         p->path_cost = port_cost(dev);
 269         p->priority = 0x8000 >> BR_PORT_BITS;
 270         p->port_no = index;
 271         p->flags = 0;
 272         br_init_port(p);
 273         p->state = BR_STATE_DISABLED;
 274         br_stp_port_timer_init(p);
 275         br_multicast_add_port(p);
 276
 277         return p;
 278 }
 279
 280 static struct device_type br_type = {
 281         .name   = "bridge",
 282 };
 283
 284 int br_add_bridge(struct net *net, const char *name)
 285 {
 286         struct net_device *dev;
 287         int ret;
 288
 289         dev = new_bridge_dev(net, name);
 290         if (!dev)
 291                 return -ENOMEM;
 292
 293         rtnl_lock();
 294         if (strchr(dev->name, '%')) {
 295                 ret = dev_alloc_name(dev, dev->name);
 296                 if (ret < 0)
 297                         goto out_free;
 298         }
 299
 300         SET_NETDEV_DEVTYPE(dev, &br_type);
 301
 302         ret = register_netdevice(dev);
 303         if (ret)
 304                 goto out_free;
 305
 306         ret = br_sysfs_addbr(dev);
 307         if (ret)
 308                 unregister_netdevice(dev);
 309  out:
 310         rtnl_unlock();
 311         return ret;
 312
 313 out_free:
 314         free_netdev(dev);
 315         goto out;
 316 }
 317
 318 int br_del_bridge(struct net *net, const char *name)
 319 {
 320         struct net_device *dev;
 321         int ret = 0;
 322
 323         rtnl_lock();
 324         dev = __dev_get_by_name(net, name);
 325         if (dev == NULL)
 326                 ret =  -ENXIO;  /* Could not find device */
 327
 328         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
 329                 /* Attempt to delete non bridge device! */
 330                 ret = -EPERM;
 331         }
 332
 333         else if (dev->flags & IFF_UP) {
 334                 /* Not shutdown yet. */
 335                 ret = -EBUSY;
 336         }
 337
 338         else
 339                 del_br(netdev_priv(dev), NULL);
 340
 341         rtnl_unlock();
 342         return ret;
 343 }
 344
 345 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
 346 int br_min_mtu(const struct net_bridge *br)
 347 {
 348         const struct net_bridge_port *p;
 349         int mtu = 0;
 350
 351         ASSERT_RTNL();
 352
 353         if (list_empty(&br->port_list))
 354                 mtu = ETH_DATA_LEN;
 355         else {
 356                 list_for_each_entry(p, &br->port_list, list) {
 357                         if (!mtu  || p->dev->mtu < mtu)
 358                                 mtu = p->dev->mtu;
 359                 }
 360         }
 361         return mtu;
 362 }
 363
 364 /*
 365  * Recomputes features using slave's features
 366  */
 367 void br_features_recompute(struct net_bridge *br)
 368 {
 369         struct net_bridge_port *p;
 370         u32 features, mask;
 371
 372         features = mask = br->feature_mask;
 373         if (list_empty(&br->port_list))
 374                 goto done;
 375
 376         features &= ~NETIF_F_ONE_FOR_ALL;
 377
 378         list_for_each_entry(p, &br->port_list, list) {
 379                 features = netdev_increment_features(features,
 380                                                      p->dev->features, mask);
 381         }
 382
 383 done:
 384         br->dev->features = netdev_fix_features(br->dev, features);
 385 }
 386
 387 /* called with RTNL */
 388 int br_add_if(struct net_bridge *br, struct net_device *dev)
 389 {
 390         struct net_bridge_port *p;
 391         int err = 0;
 392         bool changed_addr;
 393
 394         /* Don't allow bridging non-ethernet like devices */
 395         if ((dev->flags & IFF_LOOPBACK) ||
 396             dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN)
 397                 return -EINVAL;
 398
 399         /* No bridging of bridges */
 400         if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
 401                 return -ELOOP;
 402
 403         /* Device is already being bridged */
 404         if (br_port_exists(dev))
 405                 return -EBUSY;
 406
 407         /* No bridging devices that dislike that (e.g. wireless) */
 408         if (dev->priv_flags & IFF_DONT_BRIDGE)
 409                 return -EOPNOTSUPP;
 410
 411         p = new_nbp(br, dev);
 412         if (IS_ERR(p))
 413                 return PTR_ERR(p);
 414
 415         err = dev_set_promiscuity(dev, 1);
 416         if (err)
 417                 goto put_back;
 418
 419         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
 420                                    SYSFS_BRIDGE_PORT_ATTR);
 421         if (err)
 422                 goto err0;
 423
 424         err = br_fdb_insert(br, p, dev->dev_addr);
 425         if (err)
 426                 goto err1;
 427
 428         err = br_sysfs_addif(p);
 429         if (err)
 430                 goto err2;
 431
 432         if (br_netpoll_info(br) && ((err = br_netpoll_enable(p))))
 433                 goto err3;
 434
 435         err = netdev_set_master(dev, br->dev);
 436         if (err)
 437                 goto err3;
 438
 439         err = netdev_rx_handler_register(dev, br_handle_frame, p);
 440         if (err)
 441                 goto err4;
 442
 443         dev->priv_flags |= IFF_BRIDGE_PORT;
 444
 445         dev_disable_lro(dev);
 446
 447         list_add_rcu(&p->list, &br->port_list);
 448
 449         spin_lock_bh(&br->lock);
 450         changed_addr = br_stp_recalculate_bridge_id(br);
 451         br_features_recompute(br);
 452
 453         if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
 454             (br->dev->flags & IFF_UP))
 455                 br_stp_enable_port(p);
 456         spin_unlock_bh(&br->lock);
 457
 458         br_ifinfo_notify(RTM_NEWLINK, p);
 459
 460         if (changed_addr)
 461                 call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
 462
 463         dev_set_mtu(br->dev, br_min_mtu(br));
 464
 465         kobject_uevent(&p->kobj, KOBJ_ADD);
 466
 467         return 0;
 468
 469 err4:
 470         netdev_set_master(dev, NULL);
 471 err3:
 472         sysfs_remove_link(br->ifobj, p->dev->name);
 473 err2:
 474         br_fdb_delete_by_port(br, p, 1);
 475 err1:
 476         kobject_put(&p->kobj);
 477         p = NULL; /* kobject_put frees */
 478 err0:
 479         dev_set_promiscuity(dev, -1);
 480 put_back:
 481         dev_put(dev);
 482         kfree(p);
 483         return err;
 484 }
 485
 486 /* called with RTNL */
 487 int br_del_if(struct net_bridge *br, struct net_device *dev)
 488 {
 489         struct net_bridge_port *p;
 490
 491         p = br_port_get_rtnl(dev);
 492         if (!p || p->br != br)
 493                 return -EINVAL;
 494
 495         del_nbp(p);
 496
 497         spin_lock_bh(&br->lock);
 498         br_stp_recalculate_bridge_id(br);
 499         br_features_recompute(br);
 500         spin_unlock_bh(&br->lock);
 501
 502         return 0;
 503 }
 504
 505 void __net_exit br_net_exit(struct net *net)
 506 {
 507         struct net_device *dev;
 508         LIST_HEAD(list);
 509
 510         rtnl_lock();
 511         for_each_netdev(net, dev)
 512                 if (dev->priv_flags & IFF_EBRIDGE)
 513                         del_br(netdev_priv(dev), &list);
 514
 515         unregister_netdevice_many(&list);
 516         rtnl_unlock();
 517
 518 }