br_if.c revision 576eb62598f10c8c7fd75703fe89010cdcfff596 
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 */
35static 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. */
64void 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_oper_up(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_oper_up(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
86static 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
93static struct kobj_type brport_ktype = {
94#ifdef CONFIG_SYSFS
95	.sysfs_ops = &brport_sysfs_ops,
96#endif
97	.release = release_nbp,
98};
99
100static 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
111static 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 */
127static 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 */
164void 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	del_timer_sync(&br->gc_timer);
174
175	br_sysfs_delbr(br->dev);
176	unregister_netdevice_queue(br->dev, head);
177}
178
179/* find an available port number */
180static int find_portno(struct net_bridge *br)
181{
182	int index;
183	struct net_bridge_port *p;
184	unsigned long *inuse;
185
186	inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
187			GFP_KERNEL);
188	if (!inuse)
189		return -ENOMEM;
190
191	set_bit(0, inuse);	/* zero is reserved */
192	list_for_each_entry(p, &br->port_list, list) {
193		set_bit(p->port_no, inuse);
194	}
195	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
196	kfree(inuse);
197
198	return (index >= BR_MAX_PORTS) ? -EXFULL : index;
199}
200
201/* called with RTNL but without bridge lock */
202static struct net_bridge_port *new_nbp(struct net_bridge *br,
203				       struct net_device *dev)
204{
205	int index;
206	struct net_bridge_port *p;
207
208	index = find_portno(br);
209	if (index < 0)
210		return ERR_PTR(index);
211
212	p = kzalloc(sizeof(*p), GFP_KERNEL);
213	if (p == NULL)
214		return ERR_PTR(-ENOMEM);
215
216	p->br = br;
217	dev_hold(dev);
218	p->dev = dev;
219	p->path_cost = port_cost(dev);
220	p->priority = 0x8000 >> BR_PORT_BITS;
221	p->port_no = index;
222	p->flags = 0;
223	br_init_port(p);
224	p->state = BR_STATE_DISABLED;
225	br_stp_port_timer_init(p);
226	br_multicast_add_port(p);
227
228	return p;
229}
230
231int br_add_bridge(struct net *net, const char *name)
232{
233	struct net_device *dev;
234	int res;
235
236	dev = alloc_netdev(sizeof(struct net_bridge), name,
237			   br_dev_setup);
238
239	if (!dev)
240		return -ENOMEM;
241
242	dev_net_set(dev, net);
243	dev->rtnl_link_ops = &br_link_ops;
244
245	res = register_netdev(dev);
246	if (res)
247		free_netdev(dev);
248	return res;
249}
250
251int br_del_bridge(struct net *net, const char *name)
252{
253	struct net_device *dev;
254	int ret = 0;
255
256	rtnl_lock();
257	dev = __dev_get_by_name(net, name);
258	if (dev == NULL)
259		ret =  -ENXIO; 	/* Could not find device */
260
261	else if (!(dev->priv_flags & IFF_EBRIDGE)) {
262		/* Attempt to delete non bridge device! */
263		ret = -EPERM;
264	}
265
266	else if (dev->flags & IFF_UP) {
267		/* Not shutdown yet. */
268		ret = -EBUSY;
269	}
270
271	else
272		br_dev_delete(dev, NULL);
273
274	rtnl_unlock();
275	return ret;
276}
277
278/* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
279int br_min_mtu(const struct net_bridge *br)
280{
281	const struct net_bridge_port *p;
282	int mtu = 0;
283
284	ASSERT_RTNL();
285
286	if (list_empty(&br->port_list))
287		mtu = ETH_DATA_LEN;
288	else {
289		list_for_each_entry(p, &br->port_list, list) {
290			if (!mtu  || p->dev->mtu < mtu)
291				mtu = p->dev->mtu;
292		}
293	}
294	return mtu;
295}
296
297/*
298 * Recomputes features using slave's features
299 */
300netdev_features_t br_features_recompute(struct net_bridge *br,
301	netdev_features_t features)
302{
303	struct net_bridge_port *p;
304	netdev_features_t mask;
305
306	if (list_empty(&br->port_list))
307		return features;
308
309	mask = features;
310	features &= ~NETIF_F_ONE_FOR_ALL;
311
312	list_for_each_entry(p, &br->port_list, list) {
313		features = netdev_increment_features(features,
314						     p->dev->features, mask);
315	}
316
317	return features;
318}
319
320/* called with RTNL */
321int br_add_if(struct net_bridge *br, struct net_device *dev)
322{
323	struct net_bridge_port *p;
324	int err = 0;
325	bool changed_addr;
326
327	/* Don't allow bridging non-ethernet like devices */
328	if ((dev->flags & IFF_LOOPBACK) ||
329	    dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
330	    !is_valid_ether_addr(dev->dev_addr))
331		return -EINVAL;
332
333	/* No bridging of bridges */
334	if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
335		return -ELOOP;
336
337	/* Device is already being bridged */
338	if (br_port_exists(dev))
339		return -EBUSY;
340
341	/* No bridging devices that dislike that (e.g. wireless) */
342	if (dev->priv_flags & IFF_DONT_BRIDGE)
343		return -EOPNOTSUPP;
344
345	p = new_nbp(br, dev);
346	if (IS_ERR(p))
347		return PTR_ERR(p);
348
349	call_netdevice_notifiers(NETDEV_JOIN, dev);
350
351	err = dev_set_promiscuity(dev, 1);
352	if (err)
353		goto put_back;
354
355	err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
356				   SYSFS_BRIDGE_PORT_ATTR);
357	if (err)
358		goto err1;
359
360	err = br_sysfs_addif(p);
361	if (err)
362		goto err2;
363
364	if (br_netpoll_info(br) && ((err = br_netpoll_enable(p, GFP_KERNEL))))
365		goto err3;
366
367	err = netdev_set_master(dev, br->dev);
368	if (err)
369		goto err4;
370
371	err = netdev_rx_handler_register(dev, br_handle_frame, p);
372	if (err)
373		goto err5;
374
375	dev->priv_flags |= IFF_BRIDGE_PORT;
376
377	dev_disable_lro(dev);
378
379	list_add_rcu(&p->list, &br->port_list);
380
381	netdev_update_features(br->dev);
382
383	spin_lock_bh(&br->lock);
384	changed_addr = br_stp_recalculate_bridge_id(br);
385
386	if (netif_running(dev) && netif_oper_up(dev) &&
387	    (br->dev->flags & IFF_UP))
388		br_stp_enable_port(p);
389	spin_unlock_bh(&br->lock);
390
391	br_ifinfo_notify(RTM_NEWLINK, p);
392
393	if (changed_addr)
394		call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
395
396	dev_set_mtu(br->dev, br_min_mtu(br));
397
398	if (br_fdb_insert(br, p, dev->dev_addr))
399		netdev_err(dev, "failed insert local address bridge forwarding table\n");
400
401	kobject_uevent(&p->kobj, KOBJ_ADD);
402
403	return 0;
404
405err5:
406	netdev_set_master(dev, NULL);
407err4:
408	br_netpoll_disable(p);
409err3:
410	sysfs_remove_link(br->ifobj, p->dev->name);
411err2:
412	kobject_put(&p->kobj);
413	p = NULL; /* kobject_put frees */
414err1:
415	dev_set_promiscuity(dev, -1);
416put_back:
417	dev_put(dev);
418	kfree(p);
419	return err;
420}
421
422/* called with RTNL */
423int 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	/* Since more than one interface can be attached to a bridge,
433	 * there still maybe an alternate path for netconsole to use;
434	 * therefore there is no reason for a NETDEV_RELEASE event.
435	 */
436	del_nbp(p);
437
438	spin_lock_bh(&br->lock);
439	changed_addr = br_stp_recalculate_bridge_id(br);
440	spin_unlock_bh(&br->lock);
441
442	if (changed_addr)
443		call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
444
445	netdev_update_features(br->dev);
446
447	return 0;
448}
449
450void __net_exit br_net_exit(struct net *net)
451{
452	struct net_device *dev;
453	LIST_HEAD(list);
454
455	rtnl_lock();
456	for_each_netdev(net, dev)
457		if (dev->priv_flags & IFF_EBRIDGE)
458			br_dev_delete(dev, &list);
459
460	unregister_netdevice_many(&list);
461	rtnl_unlock();
462
463}
464