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         struct ethtool_cmd ecmd;
  37
  38         if (!__ethtool_get_settings(dev, &ecmd)) {
  39                 switch (ethtool_cmd_speed(&ecmd)) {
  40                 case SPEED_10000:
  41                         return 2;
  42                 case SPEED_1000:
  43                         return 4;
  44                 case SPEED_100:
  45                         return 19;
  46                 case SPEED_10:
  47                         return 100;
  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 /* Check for port carrier transistions. */
  63 void br_port_carrier_check(struct net_bridge_port *p)
  64 {
  65         struct net_device *dev = p->dev;
  66         struct net_bridge *br = p->br;
  67
  68         if (netif_running(dev) && netif_carrier_ok(dev))
  69                 p->path_cost = port_cost(dev);
  70
  71         if (!netif_running(br->dev))
  72                 return;
  73
  74         spin_lock_bh(&br->lock);
  75         if (netif_running(dev) && netif_carrier_ok(dev)) {
  76                 if (p->state == BR_STATE_DISABLED)
  77                         br_stp_enable_port(p);
  78         } else {
  79                 if (p->state != BR_STATE_DISABLED)
  80                         br_stp_disable_port(p);
  81         }
  82         spin_unlock_bh(&br->lock);
  83 }
  84
  85 static void release_nbp(struct kobject *kobj)
  86 {
  87         struct net_bridge_port *p
  88                 = container_of(kobj, struct net_bridge_port, kobj);
  89         kfree(p);
  90 }
  91
  92 static struct kobj_type brport_ktype = {
  93 #ifdef CONFIG_SYSFS
  94         .sysfs_ops = &brport_sysfs_ops,
  95 #endif
  96         .release = release_nbp,
  97 };
  98
  99 static void destroy_nbp(struct net_bridge_port *p)
 100 {
 101         struct net_device *dev = p->dev;
 102
 103         p->br = NULL;
 104         p->dev = NULL;
 105         dev_put(dev);
 106
 107         kobject_put(&p->kobj);
 108 }
 109
 110 static void destroy_nbp_rcu(struct rcu_head *head)
 111 {
 112         struct net_bridge_port *p =
 113                         container_of(head, struct net_bridge_port, rcu);
 114         destroy_nbp(p);
 115 }
 116
 117 /* Delete port(interface) from bridge is done in two steps.
 118  * via RCU. First step, marks device as down. That deletes
 119  * all the timers and stops new packets from flowing through.
 120  *
 121  * Final cleanup doesn't occur until after all CPU's finished
 122  * processing packets.
 123  *
 124  * Protected from multiple admin operations by RTNL mutex
 125  */
 126 static void del_nbp(struct net_bridge_port *p)
 127 {
 128         struct net_bridge *br = p->br;
 129         struct net_device *dev = p->dev;
 130
 131         sysfs_remove_link(br->ifobj, p->dev->name);
 132
 133         dev_set_promiscuity(dev, -1);
 134
 135         spin_lock_bh(&br->lock);
 136         br_stp_disable_port(p);
 137         spin_unlock_bh(&br->lock);
 138
 139         br_ifinfo_notify(RTM_DELLINK, p);
 140
 141         br_fdb_delete_by_port(br, p, 1);
 142
 143         list_del_rcu(&p->list);
 144
 145         dev->priv_flags &= ~IFF_BRIDGE_PORT;
 146
 147         netdev_rx_handler_unregister(dev);
 148         synchronize_net();
 149
 150         netdev_set_master(dev, NULL);
 151
 152         br_multicast_del_port(p);
 153
 154         kobject_uevent(&p->kobj, KOBJ_REMOVE);
 155         kobject_del(&p->kobj);
 156
 157         br_netpoll_disable(p);
 158
 159         call_rcu(&p->rcu, destroy_nbp_rcu);
 160 }
 161
 162 /* called with RTNL */
 163 static void del_br(struct net_bridge *br, struct list_head *head)
 164 {
 165         struct net_bridge_port *p, *n;
 166
 167         list_for_each_entry_safe(p, n, &br->port_list, list) {
 168                 del_nbp(p);
 169         }
 170
 171         del_timer_sync(&br->gc_timer);
 172
 173         br_sysfs_delbr(br->dev);
 174         unregister_netdevice_queue(br->dev, head);
 175 }
 176
 177 /* find an available port number */
 178 static int find_portno(struct net_bridge *br)
 179 {
 180         int index;
 181         struct net_bridge_port *p;
 182         unsigned long *inuse;
 183
 184         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
 185                         GFP_KERNEL);
 186         if (!inuse)
 187                 return -ENOMEM;
 188
 189         set_bit(0, inuse);      /* zero is reserved */
 190         list_for_each_entry(p, &br->port_list, list) {
 191                 set_bit(p->port_no, inuse);
 192         }
 193         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 194         kfree(inuse);
 195
 196         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
 197 }
 198
 199 /* called with RTNL but without bridge lock */
 200 static struct net_bridge_port *new_nbp(struct net_bridge *br,
 201                                        struct net_device *dev)
 202 {
 203         int index;
 204         struct net_bridge_port *p;
 205
 206         index = find_portno(br);
 207         if (index < 0)
 208                 return ERR_PTR(index);
 209
 210         p = kzalloc(sizeof(*p), GFP_KERNEL);
 211         if (p == NULL)
 212                 return ERR_PTR(-ENOMEM);
 213
 214         p->br = br;
 215         dev_hold(dev);
 216         p->dev = dev;
 217         p->path_cost = port_cost(dev);
 218         p->priority = 0x8000 >> BR_PORT_BITS;
 219         p->port_no = index;
 220         p->flags = 0;
 221         br_init_port(p);
 222         p->state = BR_STATE_DISABLED;
 223         br_stp_port_timer_init(p);
 224         br_multicast_add_port(p);
 225
 226         return p;
 227 }
 228
 229 int br_add_bridge(struct net *net, const char *name)
 230 {
 231         struct net_device *dev;
 232         int res;
 233
 234         dev = alloc_netdev(sizeof(struct net_bridge), name,
 235                            br_dev_setup);
 236
 237         if (!dev)
 238                 return -ENOMEM;
 239
 240         dev_net_set(dev, net);
 241
 242         res = register_netdev(dev);
 243         if (res)
 244                 free_netdev(dev);
 245         return res;
 246 }
 247
 248 int br_del_bridge(struct net *net, const char *name)
 249 {
 250         struct net_device *dev;
 251         int ret = 0;
 252
 253         rtnl_lock();
 254         dev = __dev_get_by_name(net, name);
 255         if (dev == NULL)
 256                 ret =  -ENXIO;  /* Could not find device */
 257
 258         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
 259                 /* Attempt to delete non bridge device! */
 260                 ret = -EPERM;
 261         }
 262
 263         else if (dev->flags & IFF_UP) {
 264                 /* Not shutdown yet. */
 265                 ret = -EBUSY;
 266         }
 267
 268         else
 269                 del_br(netdev_priv(dev), NULL);
 270
 271         rtnl_unlock();
 272         return ret;
 273 }
 274
 275 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
 276 int br_min_mtu(const struct net_bridge *br)
 277 {
 278         const struct net_bridge_port *p;
 279         int mtu = 0;
 280
 281         ASSERT_RTNL();
 282
 283         if (list_empty(&br->port_list))
 284                 mtu = ETH_DATA_LEN;
 285         else {
 286                 list_for_each_entry(p, &br->port_list, list) {
 287                         if (!mtu  || p->dev->mtu < mtu)
 288                                 mtu = p->dev->mtu;
 289                 }
 290         }
 291         return mtu;
 292 }
 293
 294 /*
 295  * Recomputes features using slave's features
 296  */
 297 u32 br_features_recompute(struct net_bridge *br, u32 features)
 298 {
 299         struct net_bridge_port *p;
 300         u32 mask;
 301
 302         if (list_empty(&br->port_list))
 303                 return features;
 304
 305         mask = features;
 306         features &= ~NETIF_F_ONE_FOR_ALL;
 307
 308         list_for_each_entry(p, &br->port_list, list) {
 309                 features = netdev_increment_features(features,
 310                                                      p->dev->features, mask);
 311         }
 312
 313         return features;
 314 }
 315
 316 /* called with RTNL */
 317 int br_add_if(struct net_bridge *br, struct net_device *dev)
 318 {
 319         struct net_bridge_port *p;
 320         int err = 0;
 321         bool changed_addr;
 322
 323         /* Don't allow bridging non-ethernet like devices */
 324         if ((dev->flags & IFF_LOOPBACK) ||
 325             dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN)
 326                 return -EINVAL;
 327
 328         /* No bridging of bridges */
 329         if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
 330                 return -ELOOP;
 331
 332         /* Device is already being bridged */
 333         if (br_port_exists(dev))
 334                 return -EBUSY;
 335
 336         /* No bridging devices that dislike that (e.g. wireless) */
 337         if (dev->priv_flags & IFF_DONT_BRIDGE)
 338                 return -EOPNOTSUPP;
 339
 340         p = new_nbp(br, dev);
 341         if (IS_ERR(p))
 342                 return PTR_ERR(p);
 343
 344         call_netdevice_notifiers(NETDEV_JOIN, dev);
 345
 346         err = dev_set_promiscuity(dev, 1);
 347         if (err)
 348                 goto put_back;
 349
 350         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
 351                                    SYSFS_BRIDGE_PORT_ATTR);
 352         if (err)
 353                 goto err0;
 354
 355         err = br_fdb_insert(br, p, dev->dev_addr);
 356         if (err)
 357                 goto err1;
 358
 359         err = br_sysfs_addif(p);
 360         if (err)
 361                 goto err2;
 362
 363         if (br_netpoll_info(br) && ((err = br_netpoll_enable(p))))
 364                 goto err3;
 365
 366         err = netdev_set_master(dev, br->dev);
 367         if (err)
 368                 goto err3;
 369
 370         err = netdev_rx_handler_register(dev, br_handle_frame, p);
 371         if (err)
 372                 goto err4;
 373
 374         dev->priv_flags |= IFF_BRIDGE_PORT;
 375
 376         dev_disable_lro(dev);
 377
 378         list_add_rcu(&p->list, &br->port_list);
 379
 380         netdev_update_features(br->dev);
 381
 382         spin_lock_bh(&br->lock);
 383         changed_addr = br_stp_recalculate_bridge_id(br);
 384
 385         if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
 386             (br->dev->flags & IFF_UP))
 387                 br_stp_enable_port(p);
 388         spin_unlock_bh(&br->lock);
 389
 390         br_ifinfo_notify(RTM_NEWLINK, p);
 391
 392         if (changed_addr)
 393                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
 394
 395         dev_set_mtu(br->dev, br_min_mtu(br));
 396
 397         kobject_uevent(&p->kobj, KOBJ_ADD);
 398
 399         return 0;
 400
 401 err4:
 402         netdev_set_master(dev, NULL);
 403 err3:
 404         sysfs_remove_link(br->ifobj, p->dev->name);
 405 err2:
 406         br_fdb_delete_by_port(br, p, 1);
 407 err1:
 408         kobject_put(&p->kobj);
 409         p = NULL; /* kobject_put frees */
 410 err0:
 411         dev_set_promiscuity(dev, -1);
 412 put_back:
 413         dev_put(dev);
 414         kfree(p);
 415         return err;
 416 }
 417
 418 /* called with RTNL */
 419 int br_del_if(struct net_bridge *br, struct net_device *dev)
 420 {
 421         struct net_bridge_port *p;
 422         bool changed_addr;
 423
 424         p = br_port_get_rtnl(dev);
 425         if (!p || p->br != br)
 426                 return -EINVAL;
 427
 428         del_nbp(p);
 429
 430         spin_lock_bh(&br->lock);
 431         changed_addr = br_stp_recalculate_bridge_id(br);
 432         spin_unlock_bh(&br->lock);
 433
 434         if (changed_addr)
 435                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
 436
 437         netdev_update_features(br->dev);
 438
 439         return 0;
 440 }
 441
 442 void __net_exit br_net_exit(struct net *net)
 443 {
 444         struct net_device *dev;
 445         LIST_HEAD(list);
 446
 447         rtnl_lock();
 448         for_each_netdev(net, dev)
 449                 if (dev->priv_flags & IFF_EBRIDGE)
 450                         del_br(netdev_priv(dev), &list);
 451
 452         unregister_netdevice_many(&list);
 453         rtnl_unlock();
 454
 455 }