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
27 #include "br_private.h"
28
29 /*
30 * Determine initial path cost based on speed.
31 * using recommendations from 802.1d standard
32 *
33 * Since driver might sleep need to not be holding any locks.
34 */
port_cost(struct net_device * dev)35 static int port_cost(struct net_device *dev)
36 {
37 struct ethtool_cmd ecmd;
38
39 if (!__ethtool_get_settings(dev, &ecmd)) {
40 switch (ethtool_cmd_speed(&ecmd)) {
41 case SPEED_10000:
42 return 2;
43 case SPEED_1000:
44 return 4;
45 case SPEED_100:
46 return 19;
47 case SPEED_10:
48 return 100;
49 }
50 }
51
52 /* Old silly heuristics based on name */
53 if (!strncmp(dev->name, "lec", 3))
54 return 7;
55
56 if (!strncmp(dev->name, "plip", 4))
57 return 2500;
58
59 return 100; /* assume old 10Mbps */
60 }
61
62
63 /* Check for port carrier transistions. */
br_port_carrier_check(struct net_bridge_port * p)64 void br_port_carrier_check(struct net_bridge_port *p)
65 {
66 struct net_device *dev = p->dev;
67 struct net_bridge *br = p->br;
68
69 if (netif_running(dev) && netif_carrier_ok(dev))
70 p->path_cost = port_cost(dev);
71
72 if (!netif_running(br->dev))
73 return;
74
75 spin_lock_bh(&br->lock);
76 if (netif_running(dev) && netif_carrier_ok(dev)) {
77 if (p->state == BR_STATE_DISABLED)
78 br_stp_enable_port(p);
79 } else {
80 if (p->state != BR_STATE_DISABLED)
81 br_stp_disable_port(p);
82 }
83 spin_unlock_bh(&br->lock);
84 }
85
release_nbp(struct kobject * kobj)86 static void release_nbp(struct kobject *kobj)
87 {
88 struct net_bridge_port *p
89 = container_of(kobj, struct net_bridge_port, kobj);
90 kfree(p);
91 }
92
93 static struct kobj_type brport_ktype = {
94 #ifdef CONFIG_SYSFS
95 .sysfs_ops = &brport_sysfs_ops,
96 #endif
97 .release = release_nbp,
98 };
99
destroy_nbp(struct net_bridge_port * p)100 static void destroy_nbp(struct net_bridge_port *p)
101 {
102 struct net_device *dev = p->dev;
103
104 p->br = NULL;
105 p->dev = NULL;
106 dev_put(dev);
107
108 kobject_put(&p->kobj);
109 }
110
destroy_nbp_rcu(struct rcu_head * head)111 static void destroy_nbp_rcu(struct rcu_head *head)
112 {
113 struct net_bridge_port *p =
114 container_of(head, struct net_bridge_port, rcu);
115 destroy_nbp(p);
116 }
117
118 /* Delete port(interface) from bridge is done in two steps.
119 * via RCU. First step, marks device as down. That deletes
120 * all the timers and stops new packets from flowing through.
121 *
122 * Final cleanup doesn't occur until after all CPU's finished
123 * processing packets.
124 *
125 * Protected from multiple admin operations by RTNL mutex
126 */
del_nbp(struct net_bridge_port * p)127 static void del_nbp(struct net_bridge_port *p)
128 {
129 struct net_bridge *br = p->br;
130 struct net_device *dev = p->dev;
131
132 sysfs_remove_link(br->ifobj, p->dev->name);
133
134 dev_set_promiscuity(dev, -1);
135
136 spin_lock_bh(&br->lock);
137 br_stp_disable_port(p);
138 spin_unlock_bh(&br->lock);
139
140 br_ifinfo_notify(RTM_DELLINK, p);
141
142 br_fdb_delete_by_port(br, p, 1);
143
144 list_del_rcu(&p->list);
145
146 dev->priv_flags &= ~IFF_BRIDGE_PORT;
147
148 netdev_rx_handler_unregister(dev);
149 synchronize_net();
150
151 netdev_set_master(dev, NULL);
152
153 br_multicast_del_port(p);
154
155 kobject_uevent(&p->kobj, KOBJ_REMOVE);
156 kobject_del(&p->kobj);
157
158 br_netpoll_disable(p);
159
160 call_rcu(&p->rcu, destroy_nbp_rcu);
161 }
162
163 /* Delete bridge device */
br_dev_delete(struct net_device * dev,struct list_head * head)164 void br_dev_delete(struct net_device *dev, struct list_head *head)
165 {
166 struct net_bridge *br = netdev_priv(dev);
167 struct net_bridge_port *p, *n;
168
169 list_for_each_entry_safe(p, n, &br->port_list, list) {
170 del_nbp(p);
171 }
172
173 br_fdb_delete_by_port(br, NULL, 1);
174
175 del_timer_sync(&br->gc_timer);
176
177 br_sysfs_delbr(br->dev);
178 unregister_netdevice_queue(br->dev, head);
179 }
180
181 /* find an available port number */
find_portno(struct net_bridge * br)182 static int find_portno(struct net_bridge *br)
183 {
184 int index;
185 struct net_bridge_port *p;
186 unsigned long *inuse;
187
188 inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
189 GFP_KERNEL);
190 if (!inuse)
191 return -ENOMEM;
192
193 set_bit(0, inuse); /* zero is reserved */
194 list_for_each_entry(p, &br->port_list, list) {
195 set_bit(p->port_no, inuse);
196 }
197 index = find_first_zero_bit(inuse, BR_MAX_PORTS);
198 kfree(inuse);
199
200 return (index >= BR_MAX_PORTS) ? -EXFULL : index;
201 }
202
203 /* called with RTNL but without bridge lock */
new_nbp(struct net_bridge * br,struct net_device * dev)204 static struct net_bridge_port *new_nbp(struct net_bridge *br,
205 struct net_device *dev)
206 {
207 int index;
208 struct net_bridge_port *p;
209
210 index = find_portno(br);
211 if (index < 0)
212 return ERR_PTR(index);
213
214 p = kzalloc(sizeof(*p), GFP_KERNEL);
215 if (p == NULL)
216 return ERR_PTR(-ENOMEM);
217
218 p->br = br;
219 dev_hold(dev);
220 p->dev = dev;
221 p->path_cost = port_cost(dev);
222 p->priority = 0x8000 >> BR_PORT_BITS;
223 p->port_no = index;
224 p->flags = 0;
225 br_init_port(p);
226 p->state = BR_STATE_DISABLED;
227 br_stp_port_timer_init(p);
228 br_multicast_add_port(p);
229
230 return p;
231 }
232
br_add_bridge(struct net * net,const char * name)233 int br_add_bridge(struct net *net, const char *name)
234 {
235 struct net_device *dev;
236 int res;
237
238 dev = alloc_netdev(sizeof(struct net_bridge), name,
239 br_dev_setup);
240
241 if (!dev)
242 return -ENOMEM;
243
244 dev_net_set(dev, net);
245 dev->rtnl_link_ops = &br_link_ops;
246
247 res = register_netdev(dev);
248 if (res)
249 free_netdev(dev);
250 return res;
251 }
252
br_del_bridge(struct net * net,const char * name)253 int br_del_bridge(struct net *net, const char *name)
254 {
255 struct net_device *dev;
256 int ret = 0;
257
258 rtnl_lock();
259 dev = __dev_get_by_name(net, name);
260 if (dev == NULL)
261 ret = -ENXIO; /* Could not find device */
262
263 else if (!(dev->priv_flags & IFF_EBRIDGE)) {
264 /* Attempt to delete non bridge device! */
265 ret = -EPERM;
266 }
267
268 else if (dev->flags & IFF_UP) {
269 /* Not shutdown yet. */
270 ret = -EBUSY;
271 }
272
273 else
274 br_dev_delete(dev, NULL);
275
276 rtnl_unlock();
277 return ret;
278 }
279
280 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
br_min_mtu(const struct net_bridge * br)281 int br_min_mtu(const struct net_bridge *br)
282 {
283 const struct net_bridge_port *p;
284 int mtu = 0;
285
286 ASSERT_RTNL();
287
288 if (list_empty(&br->port_list))
289 mtu = ETH_DATA_LEN;
290 else {
291 list_for_each_entry(p, &br->port_list, list) {
292 if (!mtu || p->dev->mtu < mtu)
293 mtu = p->dev->mtu;
294 }
295 }
296 return mtu;
297 }
298
299 /*
300 * Recomputes features using slave's features
301 */
br_features_recompute(struct net_bridge * br,netdev_features_t features)302 netdev_features_t br_features_recompute(struct net_bridge *br,
303 netdev_features_t features)
304 {
305 struct net_bridge_port *p;
306 netdev_features_t mask;
307
308 if (list_empty(&br->port_list))
309 return features;
310
311 mask = features;
312 features &= ~NETIF_F_ONE_FOR_ALL;
313
314 list_for_each_entry(p, &br->port_list, list) {
315 features = netdev_increment_features(features,
316 p->dev->features, mask);
317 }
318
319 return features;
320 }
321
322 /* called with RTNL */
br_add_if(struct net_bridge * br,struct net_device * dev)323 int br_add_if(struct net_bridge *br, struct net_device *dev)
324 {
325 struct net_bridge_port *p;
326 int err = 0;
327 bool changed_addr;
328
329 /* Don't allow bridging non-ethernet like devices */
330 if ((dev->flags & IFF_LOOPBACK) ||
331 dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
332 !is_valid_ether_addr(dev->dev_addr))
333 return -EINVAL;
334
335 /* No bridging of bridges */
336 if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
337 return -ELOOP;
338
339 /* Device is already being bridged */
340 if (br_port_exists(dev))
341 return -EBUSY;
342
343 /* No bridging devices that dislike that (e.g. wireless) */
344 if (dev->priv_flags & IFF_DONT_BRIDGE)
345 return -EOPNOTSUPP;
346
347 p = new_nbp(br, dev);
348 if (IS_ERR(p))
349 return PTR_ERR(p);
350
351 call_netdevice_notifiers(NETDEV_JOIN, dev);
352
353 err = dev_set_promiscuity(dev, 1);
354 if (err)
355 goto put_back;
356
357 err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
358 SYSFS_BRIDGE_PORT_ATTR);
359 if (err)
360 goto err1;
361
362 err = br_sysfs_addif(p);
363 if (err)
364 goto err2;
365
366 if (br_netpoll_info(br) && ((err = br_netpoll_enable(p))))
367 goto err3;
368
369 err = netdev_set_master(dev, br->dev);
370 if (err)
371 goto err3;
372
373 err = netdev_rx_handler_register(dev, br_handle_frame, p);
374 if (err)
375 goto err4;
376
377 dev->priv_flags |= IFF_BRIDGE_PORT;
378
379 dev_disable_lro(dev);
380
381 list_add_rcu(&p->list, &br->port_list);
382
383 netdev_update_features(br->dev);
384
385 spin_lock_bh(&br->lock);
386 changed_addr = br_stp_recalculate_bridge_id(br);
387
388 if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
389 (br->dev->flags & IFF_UP))
390 br_stp_enable_port(p);
391 spin_unlock_bh(&br->lock);
392
393 br_ifinfo_notify(RTM_NEWLINK, p);
394
395 if (changed_addr)
396 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
397
398 dev_set_mtu(br->dev, br_min_mtu(br));
399
400 if (br_fdb_insert(br, p, dev->dev_addr))
401 netdev_err(dev, "failed insert local address bridge forwarding table\n");
402
403 kobject_uevent(&p->kobj, KOBJ_ADD);
404
405 return 0;
406
407 err4:
408 netdev_set_master(dev, NULL);
409 err3:
410 sysfs_remove_link(br->ifobj, p->dev->name);
411 err2:
412 kobject_put(&p->kobj);
413 p = NULL; /* kobject_put frees */
414 err1:
415 dev_set_promiscuity(dev, -1);
416 put_back:
417 dev_put(dev);
418 kfree(p);
419 return err;
420 }
421
422 /* called with RTNL */
br_del_if(struct net_bridge * br,struct net_device * dev)423 int br_del_if(struct net_bridge *br, struct net_device *dev)
424 {
425 struct net_bridge_port *p;
426 bool changed_addr;
427
428 p = br_port_get_rtnl(dev);
429 if (!p || p->br != br)
430 return -EINVAL;
431
432 del_nbp(p);
433
434 spin_lock_bh(&br->lock);
435 changed_addr = br_stp_recalculate_bridge_id(br);
436 spin_unlock_bh(&br->lock);
437
438 if (changed_addr)
439 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
440
441 netdev_update_features(br->dev);
442
443 return 0;
444 }
445
br_net_exit(struct net * net)446 void __net_exit br_net_exit(struct net *net)
447 {
448 struct net_device *dev;
449 LIST_HEAD(list);
450
451 rtnl_lock();
452 for_each_netdev(net, dev)
453 if (dev->priv_flags & IFF_EBRIDGE)
454 br_dev_delete(dev, &list);
455
456 unregister_netdevice_many(&list);
457 rtnl_unlock();
458
459 }
460