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)
 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(br->dev);
 169 }
 170
 171 static struct net_device *new_bridge_dev(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
 182         br = netdev_priv(dev);
 183         br->dev = dev;
 184
 185         spin_lock_init(&br->lock);
 186         INIT_LIST_HEAD(&br->port_list);
 187         spin_lock_init(&br->hash_lock);
 188
 189         br->bridge_id.prio[0] = 0x80;
 190         br->bridge_id.prio[1] = 0x00;
 191
 192         memcpy(br->group_addr, br_group_address, ETH_ALEN);
 193
 194         br->feature_mask = dev->features;
 195         br->stp_enabled = BR_NO_STP;
 196         br->designated_root = br->bridge_id;
 197         br->root_path_cost = 0;
 198         br->root_port = 0;
 199         br->bridge_max_age = br->max_age = 20 * HZ;
 200         br->bridge_hello_time = br->hello_time = 2 * HZ;
 201         br->bridge_forward_delay = br->forward_delay = 15 * HZ;
 202         br->topology_change = 0;
 203         br->topology_change_detected = 0;
 204         br->ageing_time = 300 * HZ;
 205         INIT_LIST_HEAD(&br->age_list);
 206
 207         br_stp_timer_init(br);
 208
 209         return dev;
 210 }
 211
 212 /* find an available port number */
 213 static int find_portno(struct net_bridge *br)
 214 {
 215         int index;
 216         struct net_bridge_port *p;
 217         unsigned long *inuse;
 218
 219         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
 220                         GFP_KERNEL);
 221         if (!inuse)
 222                 return -ENOMEM;
 223
 224         set_bit(0, inuse);      /* zero is reserved */
 225         list_for_each_entry(p, &br->port_list, list) {
 226                 set_bit(p->port_no, inuse);
 227         }
 228         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 229         kfree(inuse);
 230
 231         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
 232 }
 233
 234 /* called with RTNL but without bridge lock */
 235 static struct net_bridge_port *new_nbp(struct net_bridge *br,
 236                                        struct net_device *dev)
 237 {
 238         int index;
 239         struct net_bridge_port *p;
 240
 241         index = find_portno(br);
 242         if (index < 0)
 243                 return ERR_PTR(index);
 244
 245         p = kzalloc(sizeof(*p), GFP_KERNEL);
 246         if (p == NULL)
 247                 return ERR_PTR(-ENOMEM);
 248
 249         p->br = br;
 250         dev_hold(dev);
 251         p->dev = dev;
 252         p->path_cost = port_cost(dev);
 253         p->priority = 0x8000 >> BR_PORT_BITS;
 254         p->port_no = index;
 255         br_init_port(p);
 256         p->state = BR_STATE_DISABLED;
 257         br_stp_port_timer_init(p);
 258
 259         return p;
 260 }
 261
 262 int br_add_bridge(const char *name)
 263 {
 264         struct net_device *dev;
 265         int ret;
 266
 267         dev = new_bridge_dev(name);
 268         if (!dev)
 269                 return -ENOMEM;
 270
 271         rtnl_lock();
 272         if (strchr(dev->name, '%')) {
 273                 ret = dev_alloc_name(dev, dev->name);
 274                 if (ret < 0)
 275                         goto out_free;
 276         }
 277
 278         ret = register_netdevice(dev);
 279         if (ret)
 280                 goto out_free;
 281
 282         ret = br_sysfs_addbr(dev);
 283         if (ret)
 284                 unregister_netdevice(dev);
 285  out:
 286         rtnl_unlock();
 287         return ret;
 288
 289 out_free:
 290         free_netdev(dev);
 291         goto out;
 292 }
 293
 294 int br_del_bridge(const char *name)
 295 {
 296         struct net_device *dev;
 297         int ret = 0;
 298
 299         rtnl_lock();
 300         dev = __dev_get_by_name(&init_net, name);
 301         if (dev == NULL)
 302                 ret =  -ENXIO;  /* Could not find device */
 303
 304         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
 305                 /* Attempt to delete non bridge device! */
 306                 ret = -EPERM;
 307         }
 308
 309         else if (dev->flags & IFF_UP) {
 310                 /* Not shutdown yet. */
 311                 ret = -EBUSY;
 312         }
 313
 314         else
 315                 del_br(netdev_priv(dev));
 316
 317         rtnl_unlock();
 318         return ret;
 319 }
 320
 321 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
 322 int br_min_mtu(const struct net_bridge *br)
 323 {
 324         const struct net_bridge_port *p;
 325         int mtu = 0;
 326
 327         ASSERT_RTNL();
 328
 329         if (list_empty(&br->port_list))
 330                 mtu = ETH_DATA_LEN;
 331         else {
 332                 list_for_each_entry(p, &br->port_list, list) {
 333                         if (!mtu  || p->dev->mtu < mtu)
 334                                 mtu = p->dev->mtu;
 335                 }
 336         }
 337         return mtu;
 338 }
 339
 340 /*
 341  * Recomputes features using slave's features
 342  */
 343 void br_features_recompute(struct net_bridge *br)
 344 {
 345         struct net_bridge_port *p;
 346         unsigned long features;
 347
 348         features = br->feature_mask;
 349
 350         list_for_each_entry(p, &br->port_list, list) {
 351                 features = netdev_compute_features(features, p->dev->features);
 352         }
 353
 354         br->dev->features = features;
 355 }
 356
 357 /* called with RTNL */
 358 int br_add_if(struct net_bridge *br, struct net_device *dev)
 359 {
 360         struct net_bridge_port *p;
 361         int err = 0;
 362
 363         if (dev->flags & IFF_LOOPBACK || dev->type != ARPHRD_ETHER)
 364                 return -EINVAL;
 365
 366         if (dev->hard_start_xmit == br_dev_xmit)
 367                 return -ELOOP;
 368
 369         if (dev->br_port != NULL)
 370                 return -EBUSY;
 371
 372         p = new_nbp(br, dev);
 373         if (IS_ERR(p))
 374                 return PTR_ERR(p);
 375
 376         err = dev_set_promiscuity(dev, 1);
 377         if (err)
 378                 goto put_back;
 379
 380         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
 381                                    SYSFS_BRIDGE_PORT_ATTR);
 382         if (err)
 383                 goto err0;
 384
 385         err = br_fdb_insert(br, p, dev->dev_addr);
 386         if (err)
 387                 goto err1;
 388
 389         err = br_sysfs_addif(p);
 390         if (err)
 391                 goto err2;
 392
 393         rcu_assign_pointer(dev->br_port, p);
 394         dev_disable_lro(dev);
 395
 396         list_add_rcu(&p->list, &br->port_list);
 397
 398         spin_lock_bh(&br->lock);
 399         br_stp_recalculate_bridge_id(br);
 400         br_features_recompute(br);
 401
 402         if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
 403             (br->dev->flags & IFF_UP))
 404                 br_stp_enable_port(p);
 405         spin_unlock_bh(&br->lock);
 406
 407         br_ifinfo_notify(RTM_NEWLINK, p);
 408
 409         dev_set_mtu(br->dev, br_min_mtu(br));
 410
 411         kobject_uevent(&p->kobj, KOBJ_ADD);
 412
 413         return 0;
 414 err2:
 415         br_fdb_delete_by_port(br, p, 1);
 416 err1:
 417         kobject_del(&p->kobj);
 418 err0:
 419         kobject_put(&p->kobj);
 420         dev_set_promiscuity(dev, -1);
 421 put_back:
 422         dev_put(dev);
 423         kfree(p);
 424         return err;
 425 }
 426
 427 /* called with RTNL */
 428 int br_del_if(struct net_bridge *br, struct net_device *dev)
 429 {
 430         struct net_bridge_port *p = dev->br_port;
 431
 432         if (!p || p->br != br)
 433                 return -EINVAL;
 434
 435         del_nbp(p);
 436
 437         spin_lock_bh(&br->lock);
 438         br_stp_recalculate_bridge_id(br);
 439         br_features_recompute(br);
 440         spin_unlock_bh(&br->lock);
 441
 442         return 0;
 443 }
 444
 445 void __exit br_cleanup_bridges(void)
 446 {
 447         struct net_device *dev;
 448
 449         rtnl_lock();
 450 restart:
 451         for_each_netdev(&init_net, dev) {
 452                 if (dev->priv_flags & IFF_EBRIDGE) {
 453                         del_br(dev->priv);
 454                         goto restart;
 455                 }
 456         }
 457         rtnl_unlock();
 458
 459 }