br_if.c revision cee4854122d4347b2f6f10fe7f007a48fada29a0 
1/*
2 *	Userspace interface
3 *	Linux ethernet bridge
4 *
5 *	Authors:
6 *	Lennert Buytenhek		<buytenh@gnu.org>
7 *
8 *	$Id: br_if.c,v 1.7 2001/12/24 00:59:55 davem Exp $
9 *
10 *	This program is free software; you can redistribute it and/or
11 *	modify it under the terms of the GNU General Public License
12 *	as published by the Free Software Foundation; either version
13 *	2 of the License, or (at your option) any later version.
14 */
15
16#include <linux/kernel.h>
17#include <linux/netdevice.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 <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 *
32 * Need to simulate user ioctl because not all device's that support
33 * ethtool, use ethtool_ops.  Also, since driver might sleep need to
34 * not be holding any locks.
35 */
36static int port_cost(struct net_device *dev)
37{
38	struct ethtool_cmd ecmd = { ETHTOOL_GSET };
39	struct ifreq ifr;
40	mm_segment_t old_fs;
41	int err;
42
43	strncpy(ifr.ifr_name, dev->name, IFNAMSIZ);
44	ifr.ifr_data = (void __user *) &ecmd;
45
46	old_fs = get_fs();
47	set_fs(KERNEL_DS);
48	err = dev_ethtool(&ifr);
49	set_fs(old_fs);
50
51	if (!err) {
52		switch(ecmd.speed) {
53		case SPEED_100:
54			return 19;
55		case SPEED_1000:
56			return 4;
57		case SPEED_10000:
58			return 2;
59		case SPEED_10:
60			return 100;
61		}
62	}
63
64	/* Old silly heuristics based on name */
65	if (!strncmp(dev->name, "lec", 3))
66		return 7;
67
68	if (!strncmp(dev->name, "plip", 4))
69		return 2500;
70
71	return 100;	/* assume old 10Mbps */
72}
73
74
75/*
76 * Check for port carrier transistions.
77 * Called from work queue to allow for calling functions that
78 * might sleep (such as speed check), and to debounce.
79 */
80static void port_carrier_check(void *arg)
81{
82	struct net_device *dev = arg;
83	struct net_bridge_port *p;
84	struct net_bridge *br;
85
86	rtnl_lock();
87	p = dev->br_port;
88	if (!p)
89		goto done;
90	br = p->br;
91
92	if (netif_carrier_ok(dev))
93		p->path_cost = port_cost(dev);
94
95	if (br->dev->flags & IFF_UP) {
96		spin_lock_bh(&br->lock);
97		if (netif_carrier_ok(dev)) {
98			if (p->state == BR_STATE_DISABLED)
99				br_stp_enable_port(p);
100		} else {
101			if (p->state != BR_STATE_DISABLED)
102				br_stp_disable_port(p);
103		}
104		spin_unlock_bh(&br->lock);
105	}
106done:
107	rtnl_unlock();
108}
109
110static void release_nbp(struct kobject *kobj)
111{
112	struct net_bridge_port *p
113		= container_of(kobj, struct net_bridge_port, kobj);
114	kfree(p);
115}
116
117static struct kobj_type brport_ktype = {
118#ifdef CONFIG_SYSFS
119	.sysfs_ops = &brport_sysfs_ops,
120#endif
121	.release = release_nbp,
122};
123
124static void destroy_nbp(struct net_bridge_port *p)
125{
126	struct net_device *dev = p->dev;
127
128	p->br = NULL;
129	p->dev = NULL;
130	dev_put(dev);
131
132	kobject_put(&p->kobj);
133}
134
135static void destroy_nbp_rcu(struct rcu_head *head)
136{
137	struct net_bridge_port *p =
138			container_of(head, struct net_bridge_port, rcu);
139	destroy_nbp(p);
140}
141
142/* Delete port(interface) from bridge is done in two steps.
143 * via RCU. First step, marks device as down. That deletes
144 * all the timers and stops new packets from flowing through.
145 *
146 * Final cleanup doesn't occur until after all CPU's finished
147 * processing packets.
148 *
149 * Protected from multiple admin operations by RTNL mutex
150 */
151static void del_nbp(struct net_bridge_port *p)
152{
153	struct net_bridge *br = p->br;
154	struct net_device *dev = p->dev;
155
156	sysfs_remove_link(&br->ifobj, dev->name);
157
158	dev_set_promiscuity(dev, -1);
159
160	cancel_delayed_work(&p->carrier_check);
161
162	spin_lock_bh(&br->lock);
163	br_stp_disable_port(p);
164	spin_unlock_bh(&br->lock);
165
166	br_fdb_delete_by_port(br, p);
167
168	list_del_rcu(&p->list);
169
170	rcu_assign_pointer(dev->br_port, NULL);
171
172	kobject_uevent(&p->kobj, KOBJ_REMOVE);
173	kobject_del(&p->kobj);
174
175	call_rcu(&p->rcu, destroy_nbp_rcu);
176}
177
178/* called with RTNL */
179static void del_br(struct net_bridge *br)
180{
181	struct net_bridge_port *p, *n;
182
183	list_for_each_entry_safe(p, n, &br->port_list, list) {
184		del_nbp(p);
185	}
186
187	del_timer_sync(&br->gc_timer);
188
189	br_sysfs_delbr(br->dev);
190 	unregister_netdevice(br->dev);
191}
192
193static struct net_device *new_bridge_dev(const char *name)
194{
195	struct net_bridge *br;
196	struct net_device *dev;
197
198	dev = alloc_netdev(sizeof(struct net_bridge), name,
199			   br_dev_setup);
200
201	if (!dev)
202		return NULL;
203
204	br = netdev_priv(dev);
205	br->dev = dev;
206
207	spin_lock_init(&br->lock);
208	INIT_LIST_HEAD(&br->port_list);
209	spin_lock_init(&br->hash_lock);
210
211	br->bridge_id.prio[0] = 0x80;
212	br->bridge_id.prio[1] = 0x00;
213
214	memcpy(br->group_addr, br_group_address, ETH_ALEN);
215
216	br->feature_mask = dev->features;
217	br->stp_enabled = 0;
218	br->designated_root = br->bridge_id;
219	br->root_path_cost = 0;
220	br->root_port = 0;
221	br->bridge_max_age = br->max_age = 20 * HZ;
222	br->bridge_hello_time = br->hello_time = 2 * HZ;
223	br->bridge_forward_delay = br->forward_delay = 15 * HZ;
224	br->topology_change = 0;
225	br->topology_change_detected = 0;
226	br->ageing_time = 300 * HZ;
227	INIT_LIST_HEAD(&br->age_list);
228
229	br_stp_timer_init(br);
230
231	return dev;
232}
233
234/* find an available port number */
235static int find_portno(struct net_bridge *br)
236{
237	int index;
238	struct net_bridge_port *p;
239	unsigned long *inuse;
240
241	inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
242			GFP_KERNEL);
243	if (!inuse)
244		return -ENOMEM;
245
246	set_bit(0, inuse);	/* zero is reserved */
247	list_for_each_entry(p, &br->port_list, list) {
248		set_bit(p->port_no, inuse);
249	}
250	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
251	kfree(inuse);
252
253	return (index >= BR_MAX_PORTS) ? -EXFULL : index;
254}
255
256/* called with RTNL but without bridge lock */
257static struct net_bridge_port *new_nbp(struct net_bridge *br,
258				       struct net_device *dev)
259{
260	int index;
261	struct net_bridge_port *p;
262
263	index = find_portno(br);
264	if (index < 0)
265		return ERR_PTR(index);
266
267	p = kzalloc(sizeof(*p), GFP_KERNEL);
268	if (p == NULL)
269		return ERR_PTR(-ENOMEM);
270
271	p->br = br;
272	dev_hold(dev);
273	p->dev = dev;
274	p->path_cost = port_cost(dev);
275 	p->priority = 0x8000 >> BR_PORT_BITS;
276	p->port_no = index;
277	br_init_port(p);
278	p->state = BR_STATE_DISABLED;
279	INIT_WORK(&p->carrier_check, port_carrier_check, dev);
280	br_stp_port_timer_init(p);
281
282	kobject_init(&p->kobj);
283	kobject_set_name(&p->kobj, SYSFS_BRIDGE_PORT_ATTR);
284	p->kobj.ktype = &brport_ktype;
285	p->kobj.parent = &(dev->class_dev.kobj);
286	p->kobj.kset = NULL;
287
288	return p;
289}
290
291int br_add_bridge(const char *name)
292{
293	struct net_device *dev;
294	int ret;
295
296	dev = new_bridge_dev(name);
297	if (!dev)
298		return -ENOMEM;
299
300	rtnl_lock();
301	if (strchr(dev->name, '%')) {
302		ret = dev_alloc_name(dev, dev->name);
303		if (ret < 0)
304			goto err1;
305	}
306
307	ret = register_netdevice(dev);
308	if (ret)
309		goto err2;
310
311	/* network device kobject is not setup until
312	 * after rtnl_unlock does it's hotplug magic.
313	 * so hold reference to avoid race.
314	 */
315	dev_hold(dev);
316	rtnl_unlock();
317
318	ret = br_sysfs_addbr(dev);
319	dev_put(dev);
320
321	if (ret)
322		unregister_netdev(dev);
323 out:
324	return ret;
325
326 err2:
327	free_netdev(dev);
328 err1:
329	rtnl_unlock();
330	goto out;
331}
332
333int br_del_bridge(const char *name)
334{
335	struct net_device *dev;
336	int ret = 0;
337
338	rtnl_lock();
339	dev = __dev_get_by_name(name);
340	if (dev == NULL)
341		ret =  -ENXIO; 	/* Could not find device */
342
343	else if (!(dev->priv_flags & IFF_EBRIDGE)) {
344		/* Attempt to delete non bridge device! */
345		ret = -EPERM;
346	}
347
348	else if (dev->flags & IFF_UP) {
349		/* Not shutdown yet. */
350		ret = -EBUSY;
351	}
352
353	else
354		del_br(netdev_priv(dev));
355
356	rtnl_unlock();
357	return ret;
358}
359
360/* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
361int br_min_mtu(const struct net_bridge *br)
362{
363	const struct net_bridge_port *p;
364	int mtu = 0;
365
366	ASSERT_RTNL();
367
368	if (list_empty(&br->port_list))
369		mtu = ETH_DATA_LEN;
370	else {
371		list_for_each_entry(p, &br->port_list, list) {
372			if (!mtu  || p->dev->mtu < mtu)
373				mtu = p->dev->mtu;
374		}
375	}
376	return mtu;
377}
378
379/*
380 * Recomputes features using slave's features
381 */
382void br_features_recompute(struct net_bridge *br)
383{
384	struct net_bridge_port *p;
385	unsigned long features, checksum;
386
387	features = br->feature_mask &~ NETIF_F_IP_CSUM;
388	checksum = br->feature_mask & NETIF_F_IP_CSUM;
389
390	list_for_each_entry(p, &br->port_list, list) {
391		if (!(p->dev->features
392		      & (NETIF_F_IP_CSUM|NETIF_F_NO_CSUM|NETIF_F_HW_CSUM)))
393			checksum = 0;
394		features &= p->dev->features;
395	}
396
397	br->dev->features = features | checksum | NETIF_F_LLTX;
398}
399
400/* called with RTNL */
401int br_add_if(struct net_bridge *br, struct net_device *dev)
402{
403	struct net_bridge_port *p;
404	int err = 0;
405
406	if (dev->flags & IFF_LOOPBACK || dev->type != ARPHRD_ETHER)
407		return -EINVAL;
408
409	if (dev->hard_start_xmit == br_dev_xmit)
410		return -ELOOP;
411
412	if (dev->br_port != NULL)
413		return -EBUSY;
414
415	p = new_nbp(br, dev);
416	if (IS_ERR(p))
417		return PTR_ERR(p);
418
419	err = kobject_add(&p->kobj);
420	if (err)
421		goto err0;
422
423 	err = br_fdb_insert(br, p, dev->dev_addr);
424	if (err)
425		goto err1;
426
427	err = br_sysfs_addif(p);
428	if (err)
429		goto err2;
430
431	rcu_assign_pointer(dev->br_port, p);
432	dev_set_promiscuity(dev, 1);
433
434	list_add_rcu(&p->list, &br->port_list);
435
436	spin_lock_bh(&br->lock);
437	br_stp_recalculate_bridge_id(br);
438	br_features_recompute(br);
439	schedule_delayed_work(&p->carrier_check, BR_PORT_DEBOUNCE);
440	spin_unlock_bh(&br->lock);
441
442	dev_set_mtu(br->dev, br_min_mtu(br));
443	kobject_uevent(&p->kobj, KOBJ_ADD);
444
445	return 0;
446err2:
447	br_fdb_delete_by_port(br, p);
448err1:
449	kobject_del(&p->kobj);
450err0:
451	kobject_put(&p->kobj);
452	return err;
453}
454
455/* called with RTNL */
456int br_del_if(struct net_bridge *br, struct net_device *dev)
457{
458	struct net_bridge_port *p = dev->br_port;
459
460	if (!p || p->br != br)
461		return -EINVAL;
462
463	del_nbp(p);
464
465	spin_lock_bh(&br->lock);
466	br_stp_recalculate_bridge_id(br);
467	br_features_recompute(br);
468	spin_unlock_bh(&br->lock);
469
470	return 0;
471}
472
473void __exit br_cleanup_bridges(void)
474{
475	struct net_device *dev, *nxt;
476
477	rtnl_lock();
478	for (dev = dev_base; dev; dev = nxt) {
479		nxt = dev->next;
480		if (dev->priv_flags & IFF_EBRIDGE)
481			del_br(dev->priv);
482	}
483	rtnl_unlock();
484
485}
486