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 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 (!(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         synchronize_net();
153 
154         netdev_upper_dev_unlink(dev, br->dev);
155 
156         br_multicast_del_port(p);
157 
158         kobject_uevent(&p->kobj, KOBJ_REMOVE);
159         kobject_del(&p->kobj);
160 
161         br_netpoll_disable(p);
162 
163         call_rcu(&p->rcu, destroy_nbp_rcu);
164 }
165 
166 /* Delete bridge device */
167 void br_dev_delete(struct net_device *dev, struct list_head *head)
168 {
169         struct net_bridge *br = netdev_priv(dev);
170         struct net_bridge_port *p, *n;
171 
172         list_for_each_entry_safe(p, n, &br->port_list, list) {
173                 del_nbp(p);
174         }
175 
176         del_timer_sync(&br->gc_timer);
177 
178         br_sysfs_delbr(br->dev);
179         unregister_netdevice_queue(br->dev, head);
180 }
181 
182 /* find an available port number */
183 static int find_portno(struct net_bridge *br)
184 {
185         int index;
186         struct net_bridge_port *p;
187         unsigned long *inuse;
188 
189         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
190                         GFP_KERNEL);
191         if (!inuse)
192                 return -ENOMEM;
193 
194         set_bit(0, inuse);      /* zero is reserved */
195         list_for_each_entry(p, &br->port_list, list) {
196                 set_bit(p->port_no, inuse);
197         }
198         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
199         kfree(inuse);
200 
201         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
202 }
203 
204 /* called with RTNL but without bridge lock */
205 static struct net_bridge_port *new_nbp(struct net_bridge *br,
206                                        struct net_device *dev)
207 {
208         int index;
209         struct net_bridge_port *p;
210 
211         index = find_portno(br);
212         if (index < 0)
213                 return ERR_PTR(index);
214 
215         p = kzalloc(sizeof(*p), GFP_KERNEL);
216         if (p == NULL)
217                 return ERR_PTR(-ENOMEM);
218 
219         p->br = br;
220         dev_hold(dev);
221         p->dev = dev;
222         p->path_cost = port_cost(dev);
223         p->priority = 0x8000 >> BR_PORT_BITS;
224         p->port_no = index;
225         p->flags = 0;
226         br_init_port(p);
227         p->state = BR_STATE_DISABLED;
228         br_stp_port_timer_init(p);
229         br_multicast_add_port(p);
230 
231         return p;
232 }
233 
234 int br_add_bridge(struct net *net, const char *name)
235 {
236         struct net_device *dev;
237         int res;
238 
239         dev = alloc_netdev(sizeof(struct net_bridge), name,
240                            br_dev_setup);
241 
242         if (!dev)
243                 return -ENOMEM;
244 
245         dev_net_set(dev, net);
246         dev->rtnl_link_ops = &br_link_ops;
247 
248         res = register_netdev(dev);
249         if (res)
250                 free_netdev(dev);
251         return res;
252 }
253 
254 int br_del_bridge(struct net *net, const char *name)
255 {
256         struct net_device *dev;
257         int ret = 0;
258 
259         rtnl_lock();
260         dev = __dev_get_by_name(net, name);
261         if (dev == NULL)
262                 ret =  -ENXIO;  /* Could not find device */
263 
264         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
265                 /* Attempt to delete non bridge device! */
266                 ret = -EPERM;
267         }
268 
269         else if (dev->flags & IFF_UP) {
270                 /* Not shutdown yet. */
271                 ret = -EBUSY;
272         }
273 
274         else
275                 br_dev_delete(dev, NULL);
276 
277         rtnl_unlock();
278         return ret;
279 }
280 
281 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
282 int br_min_mtu(const struct net_bridge *br)
283 {
284         const struct net_bridge_port *p;
285         int mtu = 0;
286 
287         ASSERT_RTNL();
288 
289         if (list_empty(&br->port_list))
290                 mtu = ETH_DATA_LEN;
291         else {
292                 list_for_each_entry(p, &br->port_list, list) {
293                         if (!mtu  || p->dev->mtu < mtu)
294                                 mtu = p->dev->mtu;
295                 }
296         }
297         return mtu;
298 }
299 
300 /*
301  * Recomputes features using slave's features
302  */
303 netdev_features_t br_features_recompute(struct net_bridge *br,
304         netdev_features_t features)
305 {
306         struct net_bridge_port *p;
307         netdev_features_t mask;
308 
309         if (list_empty(&br->port_list))
310                 return features;
311 
312         mask = features;
313         features &= ~NETIF_F_ONE_FOR_ALL;
314 
315         list_for_each_entry(p, &br->port_list, list) {
316                 features = netdev_increment_features(features,
317                                                      p->dev->features, mask);
318         }
319 
320         return features;
321 }
322 
323 /* called with RTNL */
324 int br_add_if(struct net_bridge *br, struct net_device *dev)
325 {
326         struct net_bridge_port *p;
327         int err = 0;
328         bool changed_addr;
329 
330         /* Don't allow bridging non-ethernet like devices */
331         if ((dev->flags & IFF_LOOPBACK) ||
332             dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
333             !is_valid_ether_addr(dev->dev_addr))
334                 return -EINVAL;
335 
336         /* No bridging of bridges */
337         if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
338                 return -ELOOP;
339 
340         /* Device is already being bridged */
341         if (br_port_exists(dev))
342                 return -EBUSY;
343 
344         /* No bridging devices that dislike that (e.g. wireless) */
345         if (dev->priv_flags & IFF_DONT_BRIDGE)
346                 return -EOPNOTSUPP;
347 
348         p = new_nbp(br, dev);
349         if (IS_ERR(p))
350                 return PTR_ERR(p);
351 
352         call_netdevice_notifiers(NETDEV_JOIN, dev);
353 
354         err = dev_set_promiscuity(dev, 1);
355         if (err)
356                 goto put_back;
357 
358         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
359                                    SYSFS_BRIDGE_PORT_ATTR);
360         if (err)
361                 goto err1;
362 
363         err = br_sysfs_addif(p);
364         if (err)
365                 goto err2;
366 
367         if (br_netpoll_info(br) && ((err = br_netpoll_enable(p, GFP_KERNEL))))
368                 goto err3;
369 
370         err = netdev_master_upper_dev_link(dev, br->dev);
371         if (err)
372                 goto err4;
373 
374         err = netdev_rx_handler_register(dev, br_handle_frame, p);
375         if (err)
376                 goto err5;
377 
378         dev->priv_flags |= IFF_BRIDGE_PORT;
379 
380         dev_disable_lro(dev);
381 
382         list_add_rcu(&p->list, &br->port_list);
383 
384         netdev_update_features(br->dev);
385 
386         spin_lock_bh(&br->lock);
387         changed_addr = br_stp_recalculate_bridge_id(br);
388 
389         if (netif_running(dev) && netif_oper_up(dev) &&
390             (br->dev->flags & IFF_UP))
391                 br_stp_enable_port(p);
392         spin_unlock_bh(&br->lock);
393 
394         br_ifinfo_notify(RTM_NEWLINK, p);
395 
396         if (changed_addr)
397                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
398 
399         dev_set_mtu(br->dev, br_min_mtu(br));
400 
401         if (br_fdb_insert(br, p, dev->dev_addr, 0))
402                 netdev_err(dev, "failed insert local address bridge forwarding table\n");
403 
404         kobject_uevent(&p->kobj, KOBJ_ADD);
405 
406         return 0;
407 
408 err5:
409         netdev_upper_dev_unlink(dev, br->dev);
410 err4:
411         br_netpoll_disable(p);
412 err3:
413         sysfs_remove_link(br->ifobj, p->dev->name);
414 err2:
415         kobject_put(&p->kobj);
416         p = NULL; /* kobject_put frees */
417 err1:
418         dev_set_promiscuity(dev, -1);
419 put_back:
420         dev_put(dev);
421         kfree(p);
422         return err;
423 }
424 
425 /* called with RTNL */
426 int br_del_if(struct net_bridge *br, struct net_device *dev)
427 {
428         struct net_bridge_port *p;
429         bool changed_addr;
430 
431         p = br_port_get_rtnl(dev);
432         if (!p || p->br != br)
433                 return -EINVAL;
434 
435         /* Since more than one interface can be attached to a bridge,
436          * there still maybe an alternate path for netconsole to use;
437          * therefore there is no reason for a NETDEV_RELEASE event.
438          */
439         del_nbp(p);
440 
441         spin_lock_bh(&br->lock);
442         changed_addr = br_stp_recalculate_bridge_id(br);
443         spin_unlock_bh(&br->lock);
444 
445         if (changed_addr)
446                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
447 
448         netdev_update_features(br->dev);
449 
450         return 0;
451 }
452 
453 void __net_exit br_net_exit(struct net *net)
454 {
455         struct net_device *dev;
456         LIST_HEAD(list);
457 
458         rtnl_lock();
459         for_each_netdev(net, dev)
460                 if (dev->priv_flags & IFF_EBRIDGE)
461                         br_dev_delete(dev, &list);
462 
463         unregister_netdevice_many(&list);
464         rtnl_unlock();
465 
466 }
467
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Linux/net/bridge/br_if.c
