br_if.c revision 384912ed194e43c03ad1cdaa09b0b1e488c34d46 
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/ethtool.h>
17#include <linux/if_arp.h>
18#include <linux/module.h>
19#include <linux/init.h>
20#include <linux/rtnetlink.h>
21#include <linux/if_ether.h>
22#include <net/sock.h>
23
24#include "br_private.h"
25
26/*
27 * Determine initial path cost based on speed.
28 * using recommendations from 802.1d standard
29 *
30 * Since driver might sleep need to not be holding any locks.
31 */
32static int port_cost(struct net_device *dev)
33{
34	if (dev->ethtool_ops && dev->ethtool_ops->get_settings) {
35		struct ethtool_cmd ecmd = { .cmd = ETHTOOL_GSET, };
36
37		if (!dev->ethtool_ops->get_settings(dev, &ecmd)) {
38			switch(ecmd.speed) {
39			case SPEED_10000:
40				return 2;
41			case SPEED_1000:
42				return 4;
43			case SPEED_100:
44				return 19;
45			case SPEED_10:
46				return 100;
47			}
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/*
63 * Check for port carrier transistions.
64 * Called from work queue to allow for calling functions that
65 * might sleep (such as speed check), and to debounce.
66 */
67void br_port_carrier_check(struct net_bridge_port *p)
68{
69	struct net_device *dev = p->dev;
70	struct net_bridge *br = p->br;
71
72	if (netif_carrier_ok(dev))
73		p->path_cost = port_cost(dev);
74
75	if (netif_running(br->dev)) {
76		spin_lock_bh(&br->lock);
77		if (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);
83		}
84		spin_unlock_bh(&br->lock);
85	}
86}
87
88static 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
95static struct kobj_type brport_ktype = {
96#ifdef CONFIG_SYSFS
97	.sysfs_ops = &brport_sysfs_ops,
98#endif
99	.release = release_nbp,
100};
101
102static 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
113static 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 */
129static 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, 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	br_fdb_delete_by_port(br, p, 1);
145
146	list_del_rcu(&p->list);
147
148	rcu_assign_pointer(dev->br_port, NULL);
149
150	kobject_uevent(&p->kobj, KOBJ_REMOVE);
151	kobject_del(&p->kobj);
152
153	call_rcu(&p->rcu, destroy_nbp_rcu);
154}
155
156/* called with RTNL */
157static void del_br(struct net_bridge *br)
158{
159	struct net_bridge_port *p, *n;
160
161	list_for_each_entry_safe(p, n, &br->port_list, list) {
162		del_nbp(p);
163	}
164
165	del_timer_sync(&br->gc_timer);
166
167	br_sysfs_delbr(br->dev);
168	unregister_netdevice(br->dev);
169}
170
171static struct net_device *new_bridge_dev(struct net *net, const char *name)
172{
173	struct net_bridge *br;
174	struct net_device *dev;
175
176	dev = alloc_netdev(sizeof(struct net_bridge), name,
177			   br_dev_setup);
178
179	if (!dev)
180		return NULL;
181	dev_net_set(dev, net);
182
183	br = netdev_priv(dev);
184	br->dev = dev;
185
186	spin_lock_init(&br->lock);
187	INIT_LIST_HEAD(&br->port_list);
188	spin_lock_init(&br->hash_lock);
189
190	br->bridge_id.prio[0] = 0x80;
191	br->bridge_id.prio[1] = 0x00;
192
193	memcpy(br->group_addr, br_group_address, ETH_ALEN);
194
195	br->feature_mask = dev->features;
196	br->stp_enabled = BR_NO_STP;
197	br->designated_root = br->bridge_id;
198	br->root_path_cost = 0;
199	br->root_port = 0;
200	br->bridge_max_age = br->max_age = 20 * HZ;
201	br->bridge_hello_time = br->hello_time = 2 * HZ;
202	br->bridge_forward_delay = br->forward_delay = 15 * HZ;
203	br->topology_change = 0;
204	br->topology_change_detected = 0;
205	br->ageing_time = 300 * HZ;
206
207	br_netfilter_rtable_init(br);
208
209	INIT_LIST_HEAD(&br->age_list);
210
211	br_stp_timer_init(br);
212
213	return dev;
214}
215
216/* find an available port number */
217static int find_portno(struct net_bridge *br)
218{
219	int index;
220	struct net_bridge_port *p;
221	unsigned long *inuse;
222
223	inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
224			GFP_KERNEL);
225	if (!inuse)
226		return -ENOMEM;
227
228	set_bit(0, inuse);	/* zero is reserved */
229	list_for_each_entry(p, &br->port_list, list) {
230		set_bit(p->port_no, inuse);
231	}
232	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
233	kfree(inuse);
234
235	return (index >= BR_MAX_PORTS) ? -EXFULL : index;
236}
237
238/* called with RTNL but without bridge lock */
239static struct net_bridge_port *new_nbp(struct net_bridge *br,
240				       struct net_device *dev)
241{
242	int index;
243	struct net_bridge_port *p;
244
245	index = find_portno(br);
246	if (index < 0)
247		return ERR_PTR(index);
248
249	p = kzalloc(sizeof(*p), GFP_KERNEL);
250	if (p == NULL)
251		return ERR_PTR(-ENOMEM);
252
253	p->br = br;
254	dev_hold(dev);
255	p->dev = dev;
256	p->path_cost = port_cost(dev);
257	p->priority = 0x8000 >> BR_PORT_BITS;
258	p->port_no = index;
259	p->flags = 0;
260	br_init_port(p);
261	p->state = BR_STATE_DISABLED;
262	br_stp_port_timer_init(p);
263
264	return p;
265}
266
267static struct device_type br_type = {
268	.name	= "bridge",
269};
270
271int br_add_bridge(struct net *net, const char *name)
272{
273	struct net_device *dev;
274	int ret;
275
276	dev = new_bridge_dev(net, name);
277	if (!dev)
278		return -ENOMEM;
279
280	rtnl_lock();
281	if (strchr(dev->name, '%')) {
282		ret = dev_alloc_name(dev, dev->name);
283		if (ret < 0)
284			goto out_free;
285	}
286
287	SET_NETDEV_DEVTYPE(dev, &br_type);
288
289	ret = register_netdevice(dev);
290	if (ret)
291		goto out_free;
292
293	ret = br_sysfs_addbr(dev);
294	if (ret)
295		unregister_netdevice(dev);
296 out:
297	rtnl_unlock();
298	return ret;
299
300out_free:
301	free_netdev(dev);
302	goto out;
303}
304
305int br_del_bridge(struct net *net, const char *name)
306{
307	struct net_device *dev;
308	int ret = 0;
309
310	rtnl_lock();
311	dev = __dev_get_by_name(net, name);
312	if (dev == NULL)
313		ret =  -ENXIO; 	/* Could not find device */
314
315	else if (!(dev->priv_flags & IFF_EBRIDGE)) {
316		/* Attempt to delete non bridge device! */
317		ret = -EPERM;
318	}
319
320	else if (dev->flags & IFF_UP) {
321		/* Not shutdown yet. */
322		ret = -EBUSY;
323	}
324
325	else
326		del_br(netdev_priv(dev));
327
328	rtnl_unlock();
329	return ret;
330}
331
332/* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
333int br_min_mtu(const struct net_bridge *br)
334{
335	const struct net_bridge_port *p;
336	int mtu = 0;
337
338	ASSERT_RTNL();
339
340	if (list_empty(&br->port_list))
341		mtu = ETH_DATA_LEN;
342	else {
343		list_for_each_entry(p, &br->port_list, list) {
344			if (!mtu  || p->dev->mtu < mtu)
345				mtu = p->dev->mtu;
346		}
347	}
348	return mtu;
349}
350
351/*
352 * Recomputes features using slave's features
353 */
354void br_features_recompute(struct net_bridge *br)
355{
356	struct net_bridge_port *p;
357	unsigned long features, mask;
358
359	features = mask = br->feature_mask;
360	if (list_empty(&br->port_list))
361		goto done;
362
363	features &= ~NETIF_F_ONE_FOR_ALL;
364
365	list_for_each_entry(p, &br->port_list, list) {
366		features = netdev_increment_features(features,
367						     p->dev->features, mask);
368	}
369
370done:
371	br->dev->features = netdev_fix_features(features, NULL);
372}
373
374/* called with RTNL */
375int br_add_if(struct net_bridge *br, struct net_device *dev)
376{
377	struct net_bridge_port *p;
378	int err = 0;
379
380	if (dev->flags & IFF_LOOPBACK || dev->type != ARPHRD_ETHER)
381		return -EINVAL;
382
383	if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
384		return -ELOOP;
385
386	if (dev->br_port != NULL)
387		return -EBUSY;
388
389	p = new_nbp(br, dev);
390	if (IS_ERR(p))
391		return PTR_ERR(p);
392
393	err = dev_set_promiscuity(dev, 1);
394	if (err)
395		goto put_back;
396
397	err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
398				   SYSFS_BRIDGE_PORT_ATTR);
399	if (err)
400		goto err0;
401
402	err = br_fdb_insert(br, p, dev->dev_addr);
403	if (err)
404		goto err1;
405
406	err = br_sysfs_addif(p);
407	if (err)
408		goto err2;
409
410	rcu_assign_pointer(dev->br_port, p);
411	dev_disable_lro(dev);
412
413	list_add_rcu(&p->list, &br->port_list);
414
415	spin_lock_bh(&br->lock);
416	br_stp_recalculate_bridge_id(br);
417	br_features_recompute(br);
418
419	if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
420	    (br->dev->flags & IFF_UP))
421		br_stp_enable_port(p);
422	spin_unlock_bh(&br->lock);
423
424	br_ifinfo_notify(RTM_NEWLINK, p);
425
426	dev_set_mtu(br->dev, br_min_mtu(br));
427
428	kobject_uevent(&p->kobj, KOBJ_ADD);
429
430	return 0;
431err2:
432	br_fdb_delete_by_port(br, p, 1);
433err1:
434	kobject_put(&p->kobj);
435err0:
436	dev_set_promiscuity(dev, -1);
437put_back:
438	dev_put(dev);
439	kfree(p);
440	return err;
441}
442
443/* called with RTNL */
444int br_del_if(struct net_bridge *br, struct net_device *dev)
445{
446	struct net_bridge_port *p = dev->br_port;
447
448	if (!p || p->br != br)
449		return -EINVAL;
450
451	del_nbp(p);
452
453	spin_lock_bh(&br->lock);
454	br_stp_recalculate_bridge_id(br);
455	br_features_recompute(br);
456	spin_unlock_bh(&br->lock);
457
458	return 0;
459}
460
461void br_net_exit(struct net *net)
462{
463	struct net_device *dev;
464
465	rtnl_lock();
466restart:
467	for_each_netdev(net, dev) {
468		if (dev->priv_flags & IFF_EBRIDGE) {
469			del_br(netdev_priv(dev));
470			goto restart;
471		}
472	}
473	rtnl_unlock();
474
475}
476