br_if.c revision 407af3299ef1ac7e87ce3fb530e32a009d1a9efd 
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 */
36static 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. */
65void 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 (netif_running(dev) && netif_oper_up(dev))
71		p->path_cost = port_cost(dev);
72
73	if (!netif_running(br->dev))
74		return;
75
76	spin_lock_bh(&br->lock);
77	if (netif_running(dev) && netif_oper_up(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
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
101static void destroy_nbp(struct net_bridge_port *p)
102{
103	struct net_device *dev = p->dev;
104
105	p->br = NULL;
106	p->dev = NULL;
107	dev_put(dev);
108
109	kobject_put(&p->kobj);
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
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 */
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
133	sysfs_remove_link(br->ifobj, p->dev->name);
134
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
141	br_ifinfo_notify(RTM_DELLINK, p);
142
143	nbp_vlan_flush(p);
144	br_fdb_delete_by_port(br, p, 1);
145
146	list_del_rcu(&p->list);
147
148	dev->priv_flags &= ~IFF_BRIDGE_PORT;
149
150	netdev_rx_handler_unregister(dev);
151	synchronize_net();
152
153	netdev_upper_dev_unlink(dev, br->dev);
154
155	br_multicast_del_port(p);
156
157	kobject_uevent(&p->kobj, KOBJ_REMOVE);
158	kobject_del(&p->kobj);
159
160	br_netpoll_disable(p);
161
162	call_rcu(&p->rcu, destroy_nbp_rcu);
163}
164
165/* Delete bridge device */
166void br_dev_delete(struct net_device *dev, struct list_head *head)
167{
168	struct net_bridge *br = netdev_priv(dev);
169	struct net_bridge_port *p, *n;
170
171	list_for_each_entry_safe(p, n, &br->port_list, list) {
172		del_nbp(p);
173	}
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 */
182static 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 */
204static 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
233int 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
253int 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 */
281int 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 */
302netdev_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 */
323int 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, GFP_KERNEL))))
367		goto err3;
368
369	err = netdev_master_upper_dev_link(dev, br->dev);
370	if (err)
371		goto err4;
372
373	err = netdev_rx_handler_register(dev, br_handle_frame, p);
374	if (err)
375		goto err5;
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 (netif_running(dev) && netif_oper_up(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
407err5:
408	netdev_upper_dev_unlink(dev, br->dev);
409err4:
410	br_netpoll_disable(p);
411err3:
412	sysfs_remove_link(br->ifobj, p->dev->name);
413err2:
414	kobject_put(&p->kobj);
415	p = NULL; /* kobject_put frees */
416err1:
417	dev_set_promiscuity(dev, -1);
418put_back:
419	dev_put(dev);
420	kfree(p);
421	return err;
422}
423
424/* called with RTNL */
425int br_del_if(struct net_bridge *br, struct net_device *dev)
426{
427	struct net_bridge_port *p;
428	bool changed_addr;
429
430	p = br_port_get_rtnl(dev);
431	if (!p || p->br != br)
432		return -EINVAL;
433
434	/* Since more than one interface can be attached to a bridge,
435	 * there still maybe an alternate path for netconsole to use;
436	 * therefore there is no reason for a NETDEV_RELEASE event.
437	 */
438	del_nbp(p);
439
440	spin_lock_bh(&br->lock);
441	changed_addr = br_stp_recalculate_bridge_id(br);
442	spin_unlock_bh(&br->lock);
443
444	if (changed_addr)
445		call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
446
447	netdev_update_features(br->dev);
448
449	return 0;
450}
451
452void __net_exit br_net_exit(struct net *net)
453{
454	struct net_device *dev;
455	LIST_HEAD(list);
456
457	rtnl_lock();
458	for_each_netdev(net, dev)
459		if (dev->priv_flags & IFF_EBRIDGE)
460			br_dev_delete(dev, &list);
461
462	unregister_netdevice_many(&list);
463	rtnl_unlock();
464
465}
466