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         br_multicast_del_port(p);
 152
 153         kobject_uevent(&p->kobj, KOBJ_REMOVE);
 154         kobject_del(&p->kobj);
 155
 156         br_netpoll_disable(p);
 157
 158         call_rcu(&p->rcu, destroy_nbp_rcu);
 159 }
 160
 161 /* called with RTNL */
 162 static void del_br(struct net_bridge *br, struct list_head *head)
 163 {
 164         struct net_bridge_port *p, *n;
 165
 166         list_for_each_entry_safe(p, n, &br->port_list, list) {
 167                 del_nbp(p);
 168         }
 169
 170         del_timer_sync(&br->gc_timer);
 171
 172         br_sysfs_delbr(br->dev);
 173         unregister_netdevice_queue(br->dev, head);
 174 }
 175
 176 static struct net_device *new_bridge_dev(struct net *net, const char *name)
 177 {
 178         struct net_bridge *br;
 179         struct net_device *dev;
 180
 181         dev = alloc_netdev(sizeof(struct net_bridge), name,
 182                            br_dev_setup);
 183
 184         if (!dev)
 185                 return NULL;
 186         dev_net_set(dev, net);
 187
 188         br = netdev_priv(dev);
 189         br->dev = dev;
 190
 191         br->stats = alloc_percpu(struct br_cpu_netstats);
 192         if (!br->stats) {
 193                 free_netdev(dev);
 194                 return NULL;
 195         }
 196
 197         spin_lock_init(&br->lock);
 198         INIT_LIST_HEAD(&br->port_list);
 199         spin_lock_init(&br->hash_lock);
 200
 201         br->bridge_id.prio[0] = 0x80;
 202         br->bridge_id.prio[1] = 0x00;
 203
 204         memcpy(br->group_addr, br_group_address, ETH_ALEN);
 205
 206         br->feature_mask = dev->features;
 207         br->stp_enabled = BR_NO_STP;
 208         br->designated_root = br->bridge_id;
 209         br->root_path_cost = 0;
 210         br->root_port = 0;
 211         br->bridge_max_age = br->max_age = 20 * HZ;
 212         br->bridge_hello_time = br->hello_time = 2 * HZ;
 213         br->bridge_forward_delay = br->forward_delay = 15 * HZ;
 214         br->topology_change = 0;
 215         br->topology_change_detected = 0;
 216         br->ageing_time = 300 * HZ;
 217
 218         br_netfilter_rtable_init(br);
 219
 220         br_stp_timer_init(br);
 221         br_multicast_init(br);
 222
 223         return dev;
 224 }
 225
 226 /* find an available port number */
 227 static int find_portno(struct net_bridge *br)
 228 {
 229         int index;
 230         struct net_bridge_port *p;
 231         unsigned long *inuse;
 232
 233         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
 234                         GFP_KERNEL);
 235         if (!inuse)
 236                 return -ENOMEM;
 237
 238         set_bit(0, inuse);      /* zero is reserved */
 239         list_for_each_entry(p, &br->port_list, list) {
 240                 set_bit(p->port_no, inuse);
 241         }
 242         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 243         kfree(inuse);
 244
 245         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
 246 }
 247
 248 /* called with RTNL but without bridge lock */
 249 static struct net_bridge_port *new_nbp(struct net_bridge *br,
 250                                        struct net_device *dev)
 251 {
 252         int index;
 253         struct net_bridge_port *p;
 254
 255         index = find_portno(br);
 256         if (index < 0)
 257                 return ERR_PTR(index);
 258
 259         p = kzalloc(sizeof(*p), GFP_KERNEL);
 260         if (p == NULL)
 261                 return ERR_PTR(-ENOMEM);
 262
 263         p->br = br;
 264         dev_hold(dev);
 265         p->dev = dev;
 266         p->path_cost = port_cost(dev);
 267         p->priority = 0x8000 >> BR_PORT_BITS;
 268         p->port_no = index;
 269         p->flags = 0;
 270         br_init_port(p);
 271         p->state = BR_STATE_DISABLED;
 272         br_stp_port_timer_init(p);
 273         br_multicast_add_port(p);
 274
 275         return p;
 276 }
 277
 278 static struct device_type br_type = {
 279         .name   = "bridge",
 280 };
 281
 282 int br_add_bridge(struct net *net, const char *name)
 283 {
 284         struct net_device *dev;
 285         int ret;
 286
 287         dev = new_bridge_dev(net, name);
 288         if (!dev)
 289                 return -ENOMEM;
 290
 291         rtnl_lock();
 292         if (strchr(dev->name, '%')) {
 293                 ret = dev_alloc_name(dev, dev->name);
 294                 if (ret < 0)
 295                         goto out_free;
 296         }
 297
 298         SET_NETDEV_DEVTYPE(dev, &br_type);
 299
 300         ret = register_netdevice(dev);
 301         if (ret)
 302                 goto out_free;
 303
 304         ret = br_sysfs_addbr(dev);
 305         if (ret)
 306                 unregister_netdevice(dev);
 307  out:
 308         rtnl_unlock();
 309         return ret;
 310
 311 out_free:
 312         free_netdev(dev);
 313         goto out;
 314 }
 315
 316 int br_del_bridge(struct net *net, const char *name)
 317 {
 318         struct net_device *dev;
 319         int ret = 0;
 320
 321         rtnl_lock();
 322         dev = __dev_get_by_name(net, name);
 323         if (dev == NULL)
 324                 ret =  -ENXIO;  /* Could not find device */
 325
 326         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
 327                 /* Attempt to delete non bridge device! */
 328                 ret = -EPERM;
 329         }
 330
 331         else if (dev->flags & IFF_UP) {
 332                 /* Not shutdown yet. */
 333                 ret = -EBUSY;
 334         }
 335
 336         else
 337                 del_br(netdev_priv(dev), NULL);
 338
 339         rtnl_unlock();
 340         return ret;
 341 }
 342
 343 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
 344 int br_min_mtu(const struct net_bridge *br)
 345 {
 346         const struct net_bridge_port *p;
 347         int mtu = 0;
 348
 349         ASSERT_RTNL();
 350
 351         if (list_empty(&br->port_list))
 352                 mtu = ETH_DATA_LEN;
 353         else {
 354                 list_for_each_entry(p, &br->port_list, list) {
 355                         if (!mtu  || p->dev->mtu < mtu)
 356                                 mtu = p->dev->mtu;
 357                 }
 358         }
 359         return mtu;
 360 }
 361
 362 /*
 363  * Recomputes features using slave's features
 364  */
 365 void br_features_recompute(struct net_bridge *br)
 366 {
 367         struct net_bridge_port *p;
 368         unsigned long features, mask;
 369
 370         features = mask = br->feature_mask;
 371         if (list_empty(&br->port_list))
 372                 goto done;
 373
 374         features &= ~NETIF_F_ONE_FOR_ALL;
 375
 376         list_for_each_entry(p, &br->port_list, list) {
 377                 features = netdev_increment_features(features,
 378                                                      p->dev->features, mask);
 379         }
 380
 381 done:
 382         br->dev->features = netdev_fix_features(features, NULL);
 383 }
 384
 385 /* called with RTNL */
 386 int br_add_if(struct net_bridge *br, struct net_device *dev)
 387 {
 388         struct net_bridge_port *p;
 389         int err = 0;
 390
 391         /* Don't allow bridging non-ethernet like devices */
 392         if ((dev->flags & IFF_LOOPBACK) ||
 393             dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN)
 394                 return -EINVAL;
 395
 396         /* No bridging of bridges */
 397         if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
 398                 return -ELOOP;
 399
 400         /* Device is already being bridged */
 401         if (br_port_exists(dev))
 402                 return -EBUSY;
 403
 404         /* No bridging devices that dislike that (e.g. wireless) */
 405         if (dev->priv_flags & IFF_DONT_BRIDGE)
 406                 return -EOPNOTSUPP;
 407
 408         p = new_nbp(br, dev);
 409         if (IS_ERR(p))
 410                 return PTR_ERR(p);
 411
 412         err = dev_set_promiscuity(dev, 1);
 413         if (err)
 414                 goto put_back;
 415
 416         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
 417                                    SYSFS_BRIDGE_PORT_ATTR);
 418         if (err)
 419                 goto err0;
 420
 421         err = br_fdb_insert(br, p, dev->dev_addr);
 422         if (err)
 423                 goto err1;
 424
 425         err = br_sysfs_addif(p);
 426         if (err)
 427                 goto err2;
 428
 429         if (br_netpoll_info(br) && ((err = br_netpoll_enable(p))))
 430                 goto err3;
 431
 432         err = netdev_rx_handler_register(dev, br_handle_frame, p);
 433         if (err)
 434                 goto err3;
 435
 436         dev->priv_flags |= IFF_BRIDGE_PORT;
 437
 438         dev_disable_lro(dev);
 439
 440         list_add_rcu(&p->list, &br->port_list);
 441
 442         spin_lock_bh(&br->lock);
 443         br_stp_recalculate_bridge_id(br);
 444         br_features_recompute(br);
 445
 446         if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
 447             (br->dev->flags & IFF_UP))
 448                 br_stp_enable_port(p);
 449         spin_unlock_bh(&br->lock);
 450
 451         br_ifinfo_notify(RTM_NEWLINK, p);
 452
 453         dev_set_mtu(br->dev, br_min_mtu(br));
 454
 455         kobject_uevent(&p->kobj, KOBJ_ADD);
 456
 457         return 0;
 458 err3:
 459         sysfs_remove_link(br->ifobj, p->dev->name);
 460 err2:
 461         br_fdb_delete_by_port(br, p, 1);
 462 err1:
 463         kobject_put(&p->kobj);
 464         p = NULL; /* kobject_put frees */
 465 err0:
 466         dev_set_promiscuity(dev, -1);
 467 put_back:
 468         dev_put(dev);
 469         kfree(p);
 470         return err;
 471 }
 472
 473 /* called with RTNL */
 474 int br_del_if(struct net_bridge *br, struct net_device *dev)
 475 {
 476         struct net_bridge_port *p;
 477
 478         if (!br_port_exists(dev))
 479                 return -EINVAL;
 480
 481         p = br_port_get(dev);
 482         if (p->br != br)
 483                 return -EINVAL;
 484
 485         del_nbp(p);
 486
 487         spin_lock_bh(&br->lock);
 488         br_stp_recalculate_bridge_id(br);
 489         br_features_recompute(br);
 490         spin_unlock_bh(&br->lock);
 491
 492         return 0;
 493 }
 494
 495 void __net_exit br_net_exit(struct net *net)
 496 {
 497         struct net_device *dev;
 498         LIST_HEAD(list);
 499
 500         rtnl_lock();
 501         for_each_netdev(net, dev)
 502                 if (dev->priv_flags & IFF_EBRIDGE)
 503                         del_br(netdev_priv(dev), &list);
 504
 505         unregister_netdevice_many(&list);
 506         rtnl_unlock();
 507
 508 }