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bridge: fix RCU races with bridge port
[net-next-2.6.git] / net / bridge / br_if.c
CommitLineData
1da177e4
LT
1/*
2 * Userspace interface
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
1da177e4
LT
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>
c06ee961 16#include <linux/netpoll.h>
1da177e4
LT
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>
46f25dff 22#include <linux/if_ether.h>
5a0e3ad6 23#include <linux/slab.h>
1da177e4
LT
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 *
61a44b9c 32 * Since driver might sleep need to not be holding any locks.
1da177e4 33 */
4433f420 34static int port_cost(struct net_device *dev)
1da177e4 35{
b4a488d1
SH
36 if (dev->ethtool_ops && dev->ethtool_ops->get_settings) {
37 struct ethtool_cmd ecmd = { .cmd = ETHTOOL_GSET, };
38
39 if (!dev->ethtool_ops->get_settings(dev, &ecmd)) {
61a44b9c 40 switch(ecmd.speed) {
61a44b9c
MW
41 case SPEED_10000:
42 return 2;
b4a488d1
SH
43 case SPEED_1000:
44 return 4;
45 case SPEED_100:
46 return 19;
61a44b9c
MW
47 case SPEED_10:
48 return 100;
49 }
1da177e4
LT
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
4433f420 63
944c794d 64/* Check for port carrier transistions. */
269def7c 65void br_port_carrier_check(struct net_bridge_port *p)
4433f420 66{
269def7c
SH
67 struct net_device *dev = p->dev;
68 struct net_bridge *br = p->br;
6e86b890 69
aa7c6e5f 70 if (netif_running(dev) && netif_carrier_ok(dev))
6e86b890
SH
71 p->path_cost = port_cost(dev);
72
aa7c6e5f 73 if (!netif_running(br->dev))
74 return;
75
76 spin_lock_bh(&br->lock);
77 if (netif_running(dev) && 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);
4433f420 83 }
aa7c6e5f 84 spin_unlock_bh(&br->lock);
4433f420
SH
85}
86
bab1deea
SH
87static void release_nbp(struct kobject *kobj)
88{
89 struct net_bridge_port *p
90 = container_of(kobj, struct net_bridge_port, kobj);
91 kfree(p);
92}
93
94static struct kobj_type brport_ktype = {
95#ifdef CONFIG_SYSFS
96 .sysfs_ops = &brport_sysfs_ops,
97#endif
98 .release = release_nbp,
99};
100
1da177e4
LT
101static void destroy_nbp(struct net_bridge_port *p)
102{
103 struct net_device *dev = p->dev;
104
1da177e4
LT
105 p->br = NULL;
106 p->dev = NULL;
107 dev_put(dev);
108
bab1deea 109 kobject_put(&p->kobj);
1da177e4
LT
110}
111
112static void destroy_nbp_rcu(struct rcu_head *head)
113{
114 struct net_bridge_port *p =
115 container_of(head, struct net_bridge_port, rcu);
116 destroy_nbp(p);
117}
118
3f4cfc2d
SH
119/* Delete port(interface) from bridge is done in two steps.
120 * via RCU. First step, marks device as down. That deletes
121 * all the timers and stops new packets from flowing through.
122 *
123 * Final cleanup doesn't occur until after all CPU's finished
124 * processing packets.
125 *
126 * Protected from multiple admin operations by RTNL mutex
127 */
1da177e4
LT
128static void del_nbp(struct net_bridge_port *p)
129{
130 struct net_bridge *br = p->br;
131 struct net_device *dev = p->dev;
132
b3bcb72e 133 sysfs_remove_link(br->ifobj, p->dev->name);
bab1deea 134
1da177e4
LT
135 dev_set_promiscuity(dev, -1);
136
137 spin_lock_bh(&br->lock);
138 br_stp_disable_port(p);
139 spin_unlock_bh(&br->lock);
140
b86c4503
SH
141 br_ifinfo_notify(RTM_DELLINK, p);
142
1a620698 143 br_fdb_delete_by_port(br, p, 1);
1da177e4
LT
144
145 list_del_rcu(&p->list);
146
f350a0a8
JP
147 dev->priv_flags &= ~IFF_BRIDGE_PORT;
148
ab95bfe0 149 netdev_rx_handler_unregister(dev);
b3f1be4b 150
3fe2d7c7
HX
151 br_multicast_del_port(p);
152
125a12cc 153 kobject_uevent(&p->kobj, KOBJ_REMOVE);
bab1deea
SH
154 kobject_del(&p->kobj);
155
91d2c34a
HX
156 br_netpoll_disable(p);
157
1da177e4
LT
158 call_rcu(&p->rcu, destroy_nbp_rcu);
159}
160
161/* called with RTNL */
8c56ba05 162static void del_br(struct net_bridge *br, struct list_head *head)
1da177e4
LT
163{
164 struct net_bridge_port *p, *n;
165
166 list_for_each_entry_safe(p, n, &br->port_list, list) {
1da177e4
LT
167 del_nbp(p);
168 }
169
170 del_timer_sync(&br->gc_timer);
171
172 br_sysfs_delbr(br->dev);
8c56ba05 173 unregister_netdevice_queue(br->dev, head);
1da177e4
LT
174}
175
4aa678ba 176static struct net_device *new_bridge_dev(struct net *net, const char *name)
1da177e4
LT
177{
178 struct net_bridge *br;
179 struct net_device *dev;
180
181 dev = alloc_netdev(sizeof(struct net_bridge), name,
182 br_dev_setup);
9d6f229f 183
1da177e4
LT
184 if (!dev)
185 return NULL;
4aa678ba 186 dev_net_set(dev, net);
1da177e4
LT
187
188 br = netdev_priv(dev);
189 br->dev = dev;
190
14bb4789 191 br->stats = alloc_percpu(struct br_cpu_netstats);
192 if (!br->stats) {
193 free_netdev(dev);
194 return NULL;
195 }
196
1da177e4
LT
197 spin_lock_init(&br->lock);
198 INIT_LIST_HEAD(&br->port_list);
199 spin_lock_init(&br->hash_lock);
200
201 br->bridge_id.prio[0] = 0x80;
202 br->bridge_id.prio[1] = 0x00;
cee48541
SH
203
204 memcpy(br->group_addr, br_group_address, ETH_ALEN);
1da177e4 205
edb5e46f 206 br->feature_mask = dev->features;
9cde0708 207 br->stp_enabled = BR_NO_STP;
1da177e4
LT
208 br->designated_root = br->bridge_id;
209 br->root_path_cost = 0;
210 br->root_port = 0;
211 br->bridge_max_age = br->max_age = 20 * HZ;
212 br->bridge_hello_time = br->hello_time = 2 * HZ;
213 br->bridge_forward_delay = br->forward_delay = 15 * HZ;
214 br->topology_change = 0;
215 br->topology_change_detected = 0;
216 br->ageing_time = 300 * HZ;
4adf0af6
SW
217
218 br_netfilter_rtable_init(br);
219
1da177e4 220 br_stp_timer_init(br);
3fe2d7c7 221 br_multicast_init(br);
1da177e4
LT
222
223 return dev;
224}
225
226/* find an available port number */
227static int find_portno(struct net_bridge *br)
228{
229 int index;
230 struct net_bridge_port *p;
231 unsigned long *inuse;
232
3b781fa1 233 inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
1da177e4
LT
234 GFP_KERNEL);
235 if (!inuse)
236 return -ENOMEM;
237
1da177e4
LT
238 set_bit(0, inuse); /* zero is reserved */
239 list_for_each_entry(p, &br->port_list, list) {
240 set_bit(p->port_no, inuse);
241 }
242 index = find_first_zero_bit(inuse, BR_MAX_PORTS);
243 kfree(inuse);
244
245 return (index >= BR_MAX_PORTS) ? -EXFULL : index;
246}
247
4433f420 248/* called with RTNL but without bridge lock */
9d6f229f 249static struct net_bridge_port *new_nbp(struct net_bridge *br,
4433f420 250 struct net_device *dev)
1da177e4
LT
251{
252 int index;
253 struct net_bridge_port *p;
9d6f229f 254
1da177e4
LT
255 index = find_portno(br);
256 if (index < 0)
257 return ERR_PTR(index);
258
cee48541 259 p = kzalloc(sizeof(*p), GFP_KERNEL);
1da177e4
LT
260 if (p == NULL)
261 return ERR_PTR(-ENOMEM);
262
1da177e4
LT
263 p->br = br;
264 dev_hold(dev);
265 p->dev = dev;
4433f420 266 p->path_cost = port_cost(dev);
9d6f229f 267 p->priority = 0x8000 >> BR_PORT_BITS;
1da177e4 268 p->port_no = index;
3982d3d2 269 p->flags = 0;
1da177e4
LT
270 br_init_port(p);
271 p->state = BR_STATE_DISABLED;
d32439c0 272 br_stp_port_timer_init(p);
3fe2d7c7 273 br_multicast_add_port(p);
1da177e4
LT
274
275 return p;
276}
277
384912ed
MH
278static struct device_type br_type = {
279 .name = "bridge",
280};
281
4aa678ba 282int br_add_bridge(struct net *net, const char *name)
1da177e4
LT
283{
284 struct net_device *dev;
285 int ret;
286
4aa678ba 287 dev = new_bridge_dev(net, name);
9d6f229f 288 if (!dev)
1da177e4
LT
289 return -ENOMEM;
290
291 rtnl_lock();
292 if (strchr(dev->name, '%')) {
293 ret = dev_alloc_name(dev, dev->name);
e340a90e
PE
294 if (ret < 0)
295 goto out_free;
1da177e4
LT
296 }
297
384912ed
MH
298 SET_NETDEV_DEVTYPE(dev, &br_type);
299
1da177e4 300 ret = register_netdevice(dev);
e340a90e
PE
301 if (ret)
302 goto out_free;
1da177e4 303
1da177e4 304 ret = br_sysfs_addbr(dev);
ac05202e 305 if (ret)
36485707
JB
306 unregister_netdevice(dev);
307 out:
1da177e4 308 rtnl_unlock();
ac05202e 309 return ret;
e340a90e
PE
310
311out_free:
312 free_netdev(dev);
313 goto out;
1da177e4
LT
314}
315
4aa678ba 316int br_del_bridge(struct net *net, const char *name)
1da177e4
LT
317{
318 struct net_device *dev;
319 int ret = 0;
320
321 rtnl_lock();
4aa678ba 322 dev = __dev_get_by_name(net, name);
9d6f229f 323 if (dev == NULL)
1da177e4
LT
324 ret = -ENXIO; /* Could not find device */
325
326 else if (!(dev->priv_flags & IFF_EBRIDGE)) {
327 /* Attempt to delete non bridge device! */
328 ret = -EPERM;
329 }
330
331 else if (dev->flags & IFF_UP) {
332 /* Not shutdown yet. */
333 ret = -EBUSY;
9d6f229f 334 }
1da177e4 335
9d6f229f 336 else
8c56ba05 337 del_br(netdev_priv(dev), NULL);
1da177e4
LT
338
339 rtnl_unlock();
340 return ret;
341}
342
46f25dff 343/* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
1da177e4
LT
344int br_min_mtu(const struct net_bridge *br)
345{
346 const struct net_bridge_port *p;
347 int mtu = 0;
348
349 ASSERT_RTNL();
350
351 if (list_empty(&br->port_list))
46f25dff 352 mtu = ETH_DATA_LEN;
1da177e4
LT
353 else {
354 list_for_each_entry(p, &br->port_list, list) {
355 if (!mtu || p->dev->mtu < mtu)
356 mtu = p->dev->mtu;
357 }
358 }
359 return mtu;
360}
361
81d35307
SH
362/*
363 * Recomputes features using slave's features
364 */
365void br_features_recompute(struct net_bridge *br)
366{
367 struct net_bridge_port *p;
b63365a2 368 unsigned long features, mask;
81d35307 369
b63365a2
HX
370 features = mask = br->feature_mask;
371 if (list_empty(&br->port_list))
372 goto done;
373
374 features &= ~NETIF_F_ONE_FOR_ALL;
81d35307
SH
375
376 list_for_each_entry(p, &br->port_list, list) {
b63365a2
HX
377 features = netdev_increment_features(features,
378 p->dev->features, mask);
81d35307
SH
379 }
380
b63365a2
HX
381done:
382 br->dev->features = netdev_fix_features(features, NULL);
81d35307
SH
383}
384
1da177e4
LT
385/* called with RTNL */
386int br_add_if(struct net_bridge *br, struct net_device *dev)
387{
388 struct net_bridge_port *p;
389 int err = 0;
390
1056bd51
SH
391 /* Don't allow bridging non-ethernet like devices */
392 if ((dev->flags & IFF_LOOPBACK) ||
393 dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN)
1da177e4
LT
394 return -EINVAL;
395
1056bd51 396 /* No bridging of bridges */
00829823 397 if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
1da177e4
LT
398 return -ELOOP;
399
1056bd51 400 /* Device is already being bridged */
f350a0a8 401 if (br_port_exists(dev))
1da177e4
LT
402 return -EBUSY;
403
ad4bb6f8
JB
404 /* No bridging devices that dislike that (e.g. wireless) */
405 if (dev->priv_flags & IFF_DONT_BRIDGE)
406 return -EOPNOTSUPP;
407
bab1deea
SH
408 p = new_nbp(br, dev);
409 if (IS_ERR(p))
1da177e4
LT
410 return PTR_ERR(p);
411
bc3f9076
WC
412 err = dev_set_promiscuity(dev, 1);
413 if (err)
414 goto put_back;
415
e32cc736
GKH
416 err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
417 SYSFS_BRIDGE_PORT_ATTR);
bab1deea
SH
418 if (err)
419 goto err0;
1da177e4 420
9d6f229f 421 err = br_fdb_insert(br, p, dev->dev_addr);
bab1deea
SH
422 if (err)
423 goto err1;
1da177e4 424
bab1deea
SH
425 err = br_sysfs_addif(p);
426 if (err)
427 goto err2;
1da177e4 428
91d2c34a
HX
429 if (br_netpoll_info(br) && ((err = br_netpoll_enable(p))))
430 goto err3;
431
f350a0a8 432 err = netdev_rx_handler_register(dev, br_handle_frame, p);
ab95bfe0 433 if (err)
f350a0a8
JP
434 goto err3;
435
436 dev->priv_flags |= IFF_BRIDGE_PORT;
ab95bfe0 437
0187bdfb 438 dev_disable_lro(dev);
bab1deea
SH
439
440 list_add_rcu(&p->list, &br->port_list);
441
442 spin_lock_bh(&br->lock);
443 br_stp_recalculate_bridge_id(br);
444 br_features_recompute(br);
de79059e
AS
445
446 if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
447 (br->dev->flags & IFF_UP))
448 br_stp_enable_port(p);
bab1deea
SH
449 spin_unlock_bh(&br->lock);
450
b86c4503
SH
451 br_ifinfo_notify(RTM_NEWLINK, p);
452
bab1deea 453 dev_set_mtu(br->dev, br_min_mtu(br));
269def7c 454
bab1deea 455 kobject_uevent(&p->kobj, KOBJ_ADD);
1da177e4 456
bab1deea 457 return 0;
91d2c34a
HX
458err3:
459 sysfs_remove_link(br->ifobj, p->dev->name);
bab1deea 460err2:
1a620698 461 br_fdb_delete_by_port(br, p, 1);
bab1deea 462err1:
c587aea9 463 kobject_put(&p->kobj);
30df94f8 464 p = NULL; /* kobject_put frees */
bab1deea 465err0:
bc3f9076 466 dev_set_promiscuity(dev, -1);
43af8532
VL
467put_back:
468 dev_put(dev);
bc3f9076 469 kfree(p);
1da177e4
LT
470 return err;
471}
472
473/* called with RTNL */
474int br_del_if(struct net_bridge *br, struct net_device *dev)
475{
f350a0a8
JP
476 struct net_bridge_port *p;
477
f350a0a8 478 p = br_port_get(dev);
b5ed54e9 479 if (!p || p->br != br)
1da177e4
LT
480 return -EINVAL;
481
1da177e4
LT
482 del_nbp(p);
483
484 spin_lock_bh(&br->lock);
485 br_stp_recalculate_bridge_id(br);
81d35307 486 br_features_recompute(br);
1da177e4
LT
487 spin_unlock_bh(&br->lock);
488
489 return 0;
490}
491
2c8c1e72 492void __net_exit br_net_exit(struct net *net)
1da177e4 493{
ab1b2046 494 struct net_device *dev;
8c56ba05 495 LIST_HEAD(list);
1da177e4
LT
496
497 rtnl_lock();
8c56ba05
ED
498 for_each_netdev(net, dev)
499 if (dev->priv_flags & IFF_EBRIDGE)
500 del_br(netdev_priv(dev), &list);
501
502 unregister_netdevice_many(&list);
1da177e4
LT
503 rtnl_unlock();
504
505}