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/ethtool.h>
  17 #include <linux/if_arp.h>
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/rtnetlink.h>
  21 #include <linux/if_ether.h>
  22 #include <net/sock.h>
  23
  24 #include "br_private.h"
  25
  26 /*
  27  * Determine initial path cost based on speed.
  28  * using recommendations from 802.1d standard
  29  *
  30  * Since driver might sleep need to not be holding any locks.
  31  */
  32 static int port_cost(struct net_device *dev)
  33 {
  34         if (dev->ethtool_ops && dev->ethtool_ops->get_settings) {
  35                 struct ethtool_cmd ecmd = { .cmd = ETHTOOL_GSET, };
  36
  37                 if (!dev->ethtool_ops->get_settings(dev, &ecmd)) {
  38                         switch(ecmd.speed) {
  39                         case SPEED_10000:
  40                                 return 2;
  41                         case SPEED_1000:
  42                                 return 4;
  43                         case SPEED_100:
  44                                 return 19;
  45                         case SPEED_10:
  46                                 return 100;
  47                         }
  48                 }
  49         }
  50
  51         /* Old silly heuristics based on name */
  52         if (!strncmp(dev->name, "lec", 3))
  53                 return 7;
  54
  55         if (!strncmp(dev->name, "plip", 4))
  56                 return 2500;
  57
  58         return 100;     /* assume old 10Mbps */
  59 }
  60
  61
  62 /*
  63  * Check for port carrier transistions.
  64  * Called from work queue to allow for calling functions that
  65  * might sleep (such as speed check), and to debounce.
  66  */
  67 void br_port_carrier_check(struct net_bridge_port *p)
  68 {
  69         struct net_device *dev = p->dev;
  70         struct net_bridge *br = p->br;
  71
  72         if (netif_carrier_ok(dev))
  73                 p->path_cost = port_cost(dev);
  74
  75         if (netif_running(br->dev)) {
  76                 spin_lock_bh(&br->lock);
  77                 if (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
  88 static void release_nbp(struct kobject *kobj)
  89 {
  90         struct net_bridge_port *p
  91                 = container_of(kobj, struct net_bridge_port, kobj);
  92         kfree(p);
  93 }
  94
  95 static struct kobj_type brport_ktype = {
  96 #ifdef CONFIG_SYSFS
  97         .sysfs_ops = &brport_sysfs_ops,
  98 #endif
  99         .release = release_nbp,
 100 };
 101
 102 static void destroy_nbp(struct net_bridge_port *p)
 103 {
 104         struct net_device *dev = p->dev;
 105
 106         p->br = NULL;
 107         p->dev = NULL;
 108         dev_put(dev);
 109
 110         kobject_put(&p->kobj);
 111 }
 112
 113 static void destroy_nbp_rcu(struct rcu_head *head)
 114 {
 115         struct net_bridge_port *p =
 116                         container_of(head, struct net_bridge_port, rcu);
 117         destroy_nbp(p);
 118 }
 119
 120 /* Delete port(interface) from bridge is done in two steps.
 121  * via RCU. First step, marks device as down. That deletes
 122  * all the timers and stops new packets from flowing through.
 123  *
 124  * Final cleanup doesn't occur until after all CPU's finished
 125  * processing packets.
 126  *
 127  * Protected from multiple admin operations by RTNL mutex
 128  */
 129 static void del_nbp(struct net_bridge_port *p)
 130 {
 131         struct net_bridge *br = p->br;
 132         struct net_device *dev = p->dev;
 133
 134         sysfs_remove_link(br->ifobj, dev->name);
 135
 136         dev_set_promiscuity(dev, -1);
 137
 138         spin_lock_bh(&br->lock);
 139         br_stp_disable_port(p);
 140         spin_unlock_bh(&br->lock);
 141
 142         br_ifinfo_notify(RTM_DELLINK, p);
 143
 144         br_fdb_delete_by_port(br, p, 1);
 145
 146         list_del_rcu(&p->list);
 147
 148         rcu_assign_pointer(dev->br_port, NULL);
 149
 150         kobject_uevent(&p->kobj, KOBJ_REMOVE);
 151         kobject_del(&p->kobj);
 152
 153         call_rcu(&p->rcu, destroy_nbp_rcu);
 154 }
 155
 156 /* called with RTNL */
 157 static void del_br(struct net_bridge *br, struct list_head *head)
 158 {
 159         struct net_bridge_port *p, *n;
 160
 161         list_for_each_entry_safe(p, n, &br->port_list, list) {
 162                 del_nbp(p);
 163         }
 164
 165         del_timer_sync(&br->gc_timer);
 166
 167         br_sysfs_delbr(br->dev);
 168         unregister_netdevice_queue(br->dev, head);
 169 }
 170
 171 static struct net_device *new_bridge_dev(struct net *net, const char *name)
 172 {
 173         struct net_bridge *br;
 174         struct net_device *dev;
 175
 176         dev = alloc_netdev(sizeof(struct net_bridge), name,
 177                            br_dev_setup);
 178
 179         if (!dev)
 180                 return NULL;
 181         dev_net_set(dev, net);
 182
 183         br = netdev_priv(dev);
 184         br->dev = dev;
 185
 186         spin_lock_init(&br->lock);
 187         INIT_LIST_HEAD(&br->port_list);
 188         spin_lock_init(&br->hash_lock);
 189
 190         br->bridge_id.prio[0] = 0x80;
 191         br->bridge_id.prio[1] = 0x00;
 192
 193         memcpy(br->group_addr, br_group_address, ETH_ALEN);
 194
 195         br->feature_mask = dev->features;
 196         br->stp_enabled = BR_NO_STP;
 197         br->designated_root = br->bridge_id;
 198         br->root_path_cost = 0;
 199         br->root_port = 0;
 200         br->bridge_max_age = br->max_age = 20 * HZ;
 201         br->bridge_hello_time = br->hello_time = 2 * HZ;
 202         br->bridge_forward_delay = br->forward_delay = 15 * HZ;
 203         br->topology_change = 0;
 204         br->topology_change_detected = 0;
 205         br->ageing_time = 300 * HZ;
 206
 207         br_netfilter_rtable_init(br);
 208
 209         INIT_LIST_HEAD(&br->age_list);
 210
 211         br_stp_timer_init(br);
 212
 213         return dev;
 214 }
 215
 216 /* find an available port number */
 217 static int find_portno(struct net_bridge *br)
 218 {
 219         int index;
 220         struct net_bridge_port *p;
 221         unsigned long *inuse;
 222
 223         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
 224                         GFP_KERNEL);
 225         if (!inuse)
 226                 return -ENOMEM;
 227
 228         set_bit(0, inuse);      /* zero is reserved */
 229         list_for_each_entry(p, &br->port_list, list) {
 230                 set_bit(p->port_no, inuse);
 231         }
 232         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 233         kfree(inuse);
 234
 235         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
 236 }
 237
 238 /* called with RTNL but without bridge lock */
 239 static struct net_bridge_port *new_nbp(struct net_bridge *br,
 240                                        struct net_device *dev)
 241 {
 242         int index;
 243         struct net_bridge_port *p;
 244
 245         index = find_portno(br);
 246         if (index < 0)
 247                 return ERR_PTR(index);
 248
 249         p = kzalloc(sizeof(*p), GFP_KERNEL);
 250         if (p == NULL)
 251                 return ERR_PTR(-ENOMEM);
 252
 253         p->br = br;
 254         dev_hold(dev);
 255         p->dev = dev;
 256         p->path_cost = port_cost(dev);
 257         p->priority = 0x8000 >> BR_PORT_BITS;
 258         p->port_no = index;
 259         p->flags = 0;
 260         br_init_port(p);
 261         p->state = BR_STATE_DISABLED;
 262         br_stp_port_timer_init(p);
 263
 264         return p;
 265 }
 266
 267 static struct device_type br_type = {
 268         .name   = "bridge",
 269 };
 270
 271 int br_add_bridge(struct net *net, const char *name)
 272 {
 273         struct net_device *dev;
 274         int ret;
 275
 276         dev = new_bridge_dev(net, name);
 277         if (!dev)
 278                 return -ENOMEM;
 279
 280         rtnl_lock();
 281         if (strchr(dev->name, '%')) {
 282                 ret = dev_alloc_name(dev, dev->name);
 283                 if (ret < 0)
 284                         goto out_free;
 285         }
 286
 287         SET_NETDEV_DEVTYPE(dev, &br_type);
 288
 289         ret = register_netdevice(dev);
 290         if (ret)
 291                 goto out_free;
 292
 293         ret = br_sysfs_addbr(dev);
 294         if (ret)
 295                 unregister_netdevice(dev);
 296  out:
 297         rtnl_unlock();
 298         return ret;
 299
 300 out_free:
 301         free_netdev(dev);
 302         goto out;
 303 }
 304
 305 int br_del_bridge(struct net *net, const char *name)
 306 {
 307         struct net_device *dev;
 308         int ret = 0;
 309
 310         rtnl_lock();
 311         dev = __dev_get_by_name(net, name);
 312         if (dev == NULL)
 313                 ret =  -ENXIO;  /* Could not find device */
 314
 315         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
 316                 /* Attempt to delete non bridge device! */
 317                 ret = -EPERM;
 318         }
 319
 320         else if (dev->flags & IFF_UP) {
 321                 /* Not shutdown yet. */
 322                 ret = -EBUSY;
 323         }
 324
 325         else
 326                 del_br(netdev_priv(dev), NULL);
 327
 328         rtnl_unlock();
 329         return ret;
 330 }
 331
 332 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
 333 int br_min_mtu(const struct net_bridge *br)
 334 {
 335         const struct net_bridge_port *p;
 336         int mtu = 0;
 337
 338         ASSERT_RTNL();
 339
 340         if (list_empty(&br->port_list))
 341                 mtu = ETH_DATA_LEN;
 342         else {
 343                 list_for_each_entry(p, &br->port_list, list) {
 344                         if (!mtu  || p->dev->mtu < mtu)
 345                                 mtu = p->dev->mtu;
 346                 }
 347         }
 348         return mtu;
 349 }
 350
 351 /*
 352  * Recomputes features using slave's features
 353  */
 354 void br_features_recompute(struct net_bridge *br)
 355 {
 356         struct net_bridge_port *p;
 357         unsigned long features, mask;
 358
 359         features = mask = br->feature_mask;
 360         if (list_empty(&br->port_list))
 361                 goto done;
 362
 363         features &= ~NETIF_F_ONE_FOR_ALL;
 364
 365         list_for_each_entry(p, &br->port_list, list) {
 366                 features = netdev_increment_features(features,
 367                                                      p->dev->features, mask);
 368         }
 369
 370 done:
 371         br->dev->features = netdev_fix_features(features, NULL);
 372 }
 373
 374 /* called with RTNL */
 375 int br_add_if(struct net_bridge *br, struct net_device *dev)
 376 {
 377         struct net_bridge_port *p;
 378         int err = 0;
 379
 380         /* Don't allow bridging non-ethernet like devices */
 381         if ((dev->flags & IFF_LOOPBACK) ||
 382             dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN)
 383                 return -EINVAL;
 384
 385         /* No bridging of bridges */
 386         if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
 387                 return -ELOOP;
 388
 389         /* Device is already being bridged */
 390         if (dev->br_port != NULL)
 391                 return -EBUSY;
 392
 393         /* No bridging devices that dislike that (e.g. wireless) */
 394         if (dev->priv_flags & IFF_DONT_BRIDGE)
 395                 return -EOPNOTSUPP;
 396
 397         p = new_nbp(br, dev);
 398         if (IS_ERR(p))
 399                 return PTR_ERR(p);
 400
 401         err = dev_set_promiscuity(dev, 1);
 402         if (err)
 403                 goto put_back;
 404
 405         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
 406                                    SYSFS_BRIDGE_PORT_ATTR);
 407         if (err)
 408                 goto err0;
 409
 410         err = br_fdb_insert(br, p, dev->dev_addr);
 411         if (err)
 412                 goto err1;
 413
 414         err = br_sysfs_addif(p);
 415         if (err)
 416                 goto err2;
 417
 418         rcu_assign_pointer(dev->br_port, p);
 419         dev_disable_lro(dev);
 420
 421         list_add_rcu(&p->list, &br->port_list);
 422
 423         spin_lock_bh(&br->lock);
 424         br_stp_recalculate_bridge_id(br);
 425         br_features_recompute(br);
 426
 427         if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
 428             (br->dev->flags & IFF_UP))
 429                 br_stp_enable_port(p);
 430         spin_unlock_bh(&br->lock);
 431
 432         br_ifinfo_notify(RTM_NEWLINK, p);
 433
 434         dev_set_mtu(br->dev, br_min_mtu(br));
 435
 436         kobject_uevent(&p->kobj, KOBJ_ADD);
 437
 438         return 0;
 439 err2:
 440         br_fdb_delete_by_port(br, p, 1);
 441 err1:
 442         kobject_put(&p->kobj);
 443         p = NULL; /* kobject_put frees */
 444 err0:
 445         dev_set_promiscuity(dev, -1);
 446 put_back:
 447         dev_put(dev);
 448         kfree(p);
 449         return err;
 450 }
 451
 452 /* called with RTNL */
 453 int br_del_if(struct net_bridge *br, struct net_device *dev)
 454 {
 455         struct net_bridge_port *p = dev->br_port;
 456
 457         if (!p || p->br != br)
 458                 return -EINVAL;
 459
 460         del_nbp(p);
 461
 462         spin_lock_bh(&br->lock);
 463         br_stp_recalculate_bridge_id(br);
 464         br_features_recompute(br);
 465         spin_unlock_bh(&br->lock);
 466
 467         return 0;
 468 }
 469
 470 void br_net_exit(struct net *net)
 471 {
 472         struct net_device *dev;
 473         LIST_HEAD(list);
 474
 475         rtnl_lock();
 476         for_each_netdev(net, dev)
 477                 if (dev->priv_flags & IFF_EBRIDGE)
 478                         del_br(netdev_priv(dev), &list);
 479
 480         unregister_netdevice_many(&list);
 481         rtnl_unlock();
 482
 483 }