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/etherdevice.h>
  17 #include <linux/netpoll.h>
  18 #include <linux/ethtool.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/rtnetlink.h>
  23 #include <linux/if_ether.h>
  24 #include <linux/slab.h>
  25 #include <net/sock.h>
  26 #include <linux/if_vlan.h>
  27
  28 #include "br_private.h"
  29
  30 /*
  31  * Determine initial path cost based on speed.
  32  * using recommendations from 802.1d standard
  33  *
  34  * Since driver might sleep need to not be holding any locks.
  35  */
  36 static int port_cost(struct net_device *dev)
  37 {
  38         struct ethtool_cmd ecmd;
  39
  40         if (!__ethtool_get_settings(dev, &ecmd)) {
  41                 switch (ethtool_cmd_speed(&ecmd)) {
  42                 case SPEED_10000:
  43                         return 2;
  44                 case SPEED_1000:
  45                         return 4;
  46                 case SPEED_100:
  47                         return 19;
  48                 case SPEED_10:
  49                         return 100;
  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 transitions. */
  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 (!(p->flags & BR_ADMIN_COST) &&
  71             netif_running(dev) && netif_oper_up(dev))
  72                 p->path_cost = port_cost(dev);
  73
  74         if (!netif_running(br->dev))
  75                 return;
  76
  77         spin_lock_bh(&br->lock);
  78         if (netif_running(dev) && netif_oper_up(dev)) {
  79                 if (p->state == BR_STATE_DISABLED)
  80                         br_stp_enable_port(p);
  81         } else {
  82                 if (p->state != BR_STATE_DISABLED)
  83                         br_stp_disable_port(p);
  84         }
  85         spin_unlock_bh(&br->lock);
  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, p->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         nbp_vlan_flush(p);
 145         br_fdb_delete_by_port(br, p, 1);
 146
 147         list_del_rcu(&p->list);
 148
 149         dev->priv_flags &= ~IFF_BRIDGE_PORT;
 150
 151         netdev_rx_handler_unregister(dev);
 152
 153         netdev_upper_dev_unlink(dev, br->dev);
 154
 155         br_multicast_del_port(p);
 156
 157         kobject_uevent(&p->kobj, KOBJ_REMOVE);
 158         kobject_del(&p->kobj);
 159
 160         br_netpoll_disable(p);
 161
 162         call_rcu(&p->rcu, destroy_nbp_rcu);
 163 }
 164
 165 /* Delete bridge device */
 166 void br_dev_delete(struct net_device *dev, struct list_head *head)
 167 {
 168         struct net_bridge *br = netdev_priv(dev);
 169         struct net_bridge_port *p, *n;
 170
 171         list_for_each_entry_safe(p, n, &br->port_list, list) {
 172                 del_nbp(p);
 173         }
 174
 175         br_fdb_delete_by_port(br, NULL, 1);
 176
 177         br_vlan_flush(br);
 178         del_timer_sync(&br->gc_timer);
 179
 180         br_sysfs_delbr(br->dev);
 181         unregister_netdevice_queue(br->dev, head);
 182 }
 183
 184 /* find an available port number */
 185 static int find_portno(struct net_bridge *br)
 186 {
 187         int index;
 188         struct net_bridge_port *p;
 189         unsigned long *inuse;
 190
 191         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
 192                         GFP_KERNEL);
 193         if (!inuse)
 194                 return -ENOMEM;
 195
 196         set_bit(0, inuse);      /* zero is reserved */
 197         list_for_each_entry(p, &br->port_list, list) {
 198                 set_bit(p->port_no, inuse);
 199         }
 200         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 201         kfree(inuse);
 202
 203         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
 204 }
 205
 206 /* called with RTNL but without bridge lock */
 207 static struct net_bridge_port *new_nbp(struct net_bridge *br,
 208                                        struct net_device *dev)
 209 {
 210         int index;
 211         struct net_bridge_port *p;
 212
 213         index = find_portno(br);
 214         if (index < 0)
 215                 return ERR_PTR(index);
 216
 217         p = kzalloc(sizeof(*p), GFP_KERNEL);
 218         if (p == NULL)
 219                 return ERR_PTR(-ENOMEM);
 220
 221         p->br = br;
 222         dev_hold(dev);
 223         p->dev = dev;
 224         p->path_cost = port_cost(dev);
 225         p->priority = 0x8000 >> BR_PORT_BITS;
 226         p->port_no = index;
 227         p->flags = BR_LEARNING | BR_FLOOD;
 228         br_init_port(p);
 229         p->state = BR_STATE_DISABLED;
 230         br_stp_port_timer_init(p);
 231         br_multicast_add_port(p);
 232
 233         return p;
 234 }
 235
 236 int br_add_bridge(struct net *net, const char *name)
 237 {
 238         struct net_device *dev;
 239         int res;
 240
 241         dev = alloc_netdev(sizeof(struct net_bridge), name,
 242                            br_dev_setup);
 243
 244         if (!dev)
 245                 return -ENOMEM;
 246
 247         dev_net_set(dev, net);
 248         dev->rtnl_link_ops = &br_link_ops;
 249
 250         res = register_netdev(dev);
 251         if (res)
 252                 free_netdev(dev);
 253         return res;
 254 }
 255
 256 int br_del_bridge(struct net *net, const char *name)
 257 {
 258         struct net_device *dev;
 259         int ret = 0;
 260
 261         rtnl_lock();
 262         dev = __dev_get_by_name(net, name);
 263         if (dev == NULL)
 264                 ret =  -ENXIO;  /* Could not find device */
 265
 266         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
 267                 /* Attempt to delete non bridge device! */
 268                 ret = -EPERM;
 269         }
 270
 271         else if (dev->flags & IFF_UP) {
 272                 /* Not shutdown yet. */
 273                 ret = -EBUSY;
 274         }
 275
 276         else
 277                 br_dev_delete(dev, NULL);
 278
 279         rtnl_unlock();
 280         return ret;
 281 }
 282
 283 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
 284 int br_min_mtu(const struct net_bridge *br)
 285 {
 286         const struct net_bridge_port *p;
 287         int mtu = 0;
 288
 289         ASSERT_RTNL();
 290
 291         if (list_empty(&br->port_list))
 292                 mtu = ETH_DATA_LEN;
 293         else {
 294                 list_for_each_entry(p, &br->port_list, list) {
 295                         if (!mtu  || p->dev->mtu < mtu)
 296                                 mtu = p->dev->mtu;
 297                 }
 298         }
 299         return mtu;
 300 }
 301
 302 /*
 303  * Recomputes features using slave's features
 304  */
 305 netdev_features_t br_features_recompute(struct net_bridge *br,
 306         netdev_features_t features)
 307 {
 308         struct net_bridge_port *p;
 309         netdev_features_t mask;
 310
 311         if (list_empty(&br->port_list))
 312                 return features;
 313
 314         mask = features;
 315         features &= ~NETIF_F_ONE_FOR_ALL;
 316
 317         list_for_each_entry(p, &br->port_list, list) {
 318                 features = netdev_increment_features(features,
 319                                                      p->dev->features, mask);
 320         }
 321
 322         return features;
 323 }
 324
 325 /* called with RTNL */
 326 int br_add_if(struct net_bridge *br, struct net_device *dev)
 327 {
 328         struct net_bridge_port *p;
 329         int err = 0;
 330         bool changed_addr;
 331
 332         /* Don't allow bridging non-ethernet like devices */
 333         if ((dev->flags & IFF_LOOPBACK) ||
 334             dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
 335             !is_valid_ether_addr(dev->dev_addr))
 336                 return -EINVAL;
 337
 338         /* No bridging of bridges */
 339         if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
 340                 return -ELOOP;
 341
 342         /* Device is already being bridged */
 343         if (br_port_exists(dev))
 344                 return -EBUSY;
 345
 346         /* No bridging devices that dislike that (e.g. wireless) */
 347         if (dev->priv_flags & IFF_DONT_BRIDGE)
 348                 return -EOPNOTSUPP;
 349
 350         p = new_nbp(br, dev);
 351         if (IS_ERR(p))
 352                 return PTR_ERR(p);
 353
 354         call_netdevice_notifiers(NETDEV_JOIN, dev);
 355
 356         err = dev_set_promiscuity(dev, 1);
 357         if (err)
 358                 goto put_back;
 359
 360         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
 361                                    SYSFS_BRIDGE_PORT_ATTR);
 362         if (err)
 363                 goto err1;
 364
 365         err = br_sysfs_addif(p);
 366         if (err)
 367                 goto err2;
 368
 369         err = br_netpoll_enable(p, GFP_KERNEL);
 370         if (err)
 371                 goto err3;
 372
 373         err = netdev_master_upper_dev_link(dev, br->dev);
 374         if (err)
 375                 goto err4;
 376
 377         err = netdev_rx_handler_register(dev, br_handle_frame, p);
 378         if (err)
 379                 goto err5;
 380
 381         dev->priv_flags |= IFF_BRIDGE_PORT;
 382
 383         dev_disable_lro(dev);
 384
 385         list_add_rcu(&p->list, &br->port_list);
 386
 387         netdev_update_features(br->dev);
 388
 389         if (br->dev->needed_headroom < dev->needed_headroom)
 390                 br->dev->needed_headroom = dev->needed_headroom;
 391
 392         if (br_fdb_insert(br, p, dev->dev_addr, 0))
 393                 netdev_err(dev, "failed insert local address bridge forwarding table\n");
 394
 395         spin_lock_bh(&br->lock);
 396         changed_addr = br_stp_recalculate_bridge_id(br);
 397
 398         if (netif_running(dev) && netif_oper_up(dev) &&
 399             (br->dev->flags & IFF_UP))
 400                 br_stp_enable_port(p);
 401         spin_unlock_bh(&br->lock);
 402
 403         br_ifinfo_notify(RTM_NEWLINK, p);
 404
 405         if (changed_addr)
 406                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
 407
 408         dev_set_mtu(br->dev, br_min_mtu(br));
 409
 410         kobject_uevent(&p->kobj, KOBJ_ADD);
 411
 412         return 0;
 413
 414 err5:
 415         netdev_upper_dev_unlink(dev, br->dev);
 416 err4:
 417         br_netpoll_disable(p);
 418 err3:
 419         sysfs_remove_link(br->ifobj, p->dev->name);
 420 err2:
 421         kobject_put(&p->kobj);
 422         p = NULL; /* kobject_put frees */
 423 err1:
 424         dev_set_promiscuity(dev, -1);
 425 put_back:
 426         dev_put(dev);
 427         kfree(p);
 428         return err;
 429 }
 430
 431 /* called with RTNL */
 432 int br_del_if(struct net_bridge *br, struct net_device *dev)
 433 {
 434         struct net_bridge_port *p;
 435         bool changed_addr;
 436
 437         p = br_port_get_rtnl(dev);
 438         if (!p || p->br != br)
 439                 return -EINVAL;
 440
 441         /* Since more than one interface can be attached to a bridge,
 442          * there still maybe an alternate path for netconsole to use;
 443          * therefore there is no reason for a NETDEV_RELEASE event.
 444          */
 445         del_nbp(p);
 446
 447         spin_lock_bh(&br->lock);
 448         changed_addr = br_stp_recalculate_bridge_id(br);
 449         spin_unlock_bh(&br->lock);
 450
 451         if (changed_addr)
 452                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
 453
 454         netdev_update_features(br->dev);
 455
 456         return 0;
 457 }