br_if.c revision 7562f876cd93800f2f8c89445f2a563590b24e09 
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 */
80void br_port_carrier_check(struct net_bridge_port *p)
81{
82	struct net_device *dev = p->dev;
83	struct net_bridge *br = p->br;
84
85	if (netif_carrier_ok(dev))
86		p->path_cost = port_cost(dev);
87
88	if (netif_running(br->dev)) {
89		spin_lock_bh(&br->lock);
90		if (netif_carrier_ok(dev)) {
91			if (p->state == BR_STATE_DISABLED)
92				br_stp_enable_port(p);
93		} else {
94			if (p->state != BR_STATE_DISABLED)
95				br_stp_disable_port(p);
96		}
97		spin_unlock_bh(&br->lock);
98	}
99}
100
101static void release_nbp(struct kobject *kobj)
102{
103	struct net_bridge_port *p
104		= container_of(kobj, struct net_bridge_port, kobj);
105	kfree(p);
106}
107
108static struct kobj_type brport_ktype = {
109#ifdef CONFIG_SYSFS
110	.sysfs_ops = &brport_sysfs_ops,
111#endif
112	.release = release_nbp,
113};
114
115static void destroy_nbp(struct net_bridge_port *p)
116{
117	struct net_device *dev = p->dev;
118
119	p->br = NULL;
120	p->dev = NULL;
121	dev_put(dev);
122
123	kobject_put(&p->kobj);
124}
125
126static void destroy_nbp_rcu(struct rcu_head *head)
127{
128	struct net_bridge_port *p =
129			container_of(head, struct net_bridge_port, rcu);
130	destroy_nbp(p);
131}
132
133/* Delete port(interface) from bridge is done in two steps.
134 * via RCU. First step, marks device as down. That deletes
135 * all the timers and stops new packets from flowing through.
136 *
137 * Final cleanup doesn't occur until after all CPU's finished
138 * processing packets.
139 *
140 * Protected from multiple admin operations by RTNL mutex
141 */
142static void del_nbp(struct net_bridge_port *p)
143{
144	struct net_bridge *br = p->br;
145	struct net_device *dev = p->dev;
146
147	sysfs_remove_link(&br->ifobj, dev->name);
148
149	dev_set_promiscuity(dev, -1);
150
151	spin_lock_bh(&br->lock);
152	br_stp_disable_port(p);
153	spin_unlock_bh(&br->lock);
154
155	br_ifinfo_notify(RTM_DELLINK, p);
156
157	br_fdb_delete_by_port(br, p, 1);
158
159	list_del_rcu(&p->list);
160
161	rcu_assign_pointer(dev->br_port, NULL);
162
163	kobject_uevent(&p->kobj, KOBJ_REMOVE);
164	kobject_del(&p->kobj);
165
166	call_rcu(&p->rcu, destroy_nbp_rcu);
167}
168
169/* called with RTNL */
170static void del_br(struct net_bridge *br)
171{
172	struct net_bridge_port *p, *n;
173
174	list_for_each_entry_safe(p, n, &br->port_list, list) {
175		del_nbp(p);
176	}
177
178	del_timer_sync(&br->gc_timer);
179
180	br_sysfs_delbr(br->dev);
181	unregister_netdevice(br->dev);
182}
183
184static struct net_device *new_bridge_dev(const char *name)
185{
186	struct net_bridge *br;
187	struct net_device *dev;
188
189	dev = alloc_netdev(sizeof(struct net_bridge), name,
190			   br_dev_setup);
191
192	if (!dev)
193		return NULL;
194
195	br = netdev_priv(dev);
196	br->dev = dev;
197
198	spin_lock_init(&br->lock);
199	INIT_LIST_HEAD(&br->port_list);
200	spin_lock_init(&br->hash_lock);
201
202	br->bridge_id.prio[0] = 0x80;
203	br->bridge_id.prio[1] = 0x00;
204
205	memcpy(br->group_addr, br_group_address, ETH_ALEN);
206
207	br->feature_mask = dev->features;
208	br->stp_enabled = BR_NO_STP;
209	br->designated_root = br->bridge_id;
210	br->root_path_cost = 0;
211	br->root_port = 0;
212	br->bridge_max_age = br->max_age = 20 * HZ;
213	br->bridge_hello_time = br->hello_time = 2 * HZ;
214	br->bridge_forward_delay = br->forward_delay = 15 * HZ;
215	br->topology_change = 0;
216	br->topology_change_detected = 0;
217	br->ageing_time = 300 * HZ;
218	INIT_LIST_HEAD(&br->age_list);
219
220	br_stp_timer_init(br);
221
222	return dev;
223}
224
225/* find an available port number */
226static int find_portno(struct net_bridge *br)
227{
228	int index;
229	struct net_bridge_port *p;
230	unsigned long *inuse;
231
232	inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
233			GFP_KERNEL);
234	if (!inuse)
235		return -ENOMEM;
236
237	set_bit(0, inuse);	/* zero is reserved */
238	list_for_each_entry(p, &br->port_list, list) {
239		set_bit(p->port_no, inuse);
240	}
241	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
242	kfree(inuse);
243
244	return (index >= BR_MAX_PORTS) ? -EXFULL : index;
245}
246
247/* called with RTNL but without bridge lock */
248static struct net_bridge_port *new_nbp(struct net_bridge *br,
249				       struct net_device *dev)
250{
251	int index;
252	struct net_bridge_port *p;
253
254	index = find_portno(br);
255	if (index < 0)
256		return ERR_PTR(index);
257
258	p = kzalloc(sizeof(*p), GFP_KERNEL);
259	if (p == NULL)
260		return ERR_PTR(-ENOMEM);
261
262	p->br = br;
263	dev_hold(dev);
264	p->dev = dev;
265	p->path_cost = port_cost(dev);
266	p->priority = 0x8000 >> BR_PORT_BITS;
267	p->port_no = index;
268	br_init_port(p);
269	p->state = BR_STATE_DISABLED;
270	br_stp_port_timer_init(p);
271
272	kobject_init(&p->kobj);
273	kobject_set_name(&p->kobj, SYSFS_BRIDGE_PORT_ATTR);
274	p->kobj.ktype = &brport_ktype;
275	p->kobj.parent = &(dev->dev.kobj);
276	p->kobj.kset = NULL;
277
278	return p;
279}
280
281int br_add_bridge(const char *name)
282{
283	struct net_device *dev;
284	int ret;
285
286	dev = new_bridge_dev(name);
287	if (!dev)
288		return -ENOMEM;
289
290	rtnl_lock();
291	if (strchr(dev->name, '%')) {
292		ret = dev_alloc_name(dev, dev->name);
293		if (ret < 0) {
294			free_netdev(dev);
295			goto out;
296		}
297	}
298
299	ret = register_netdevice(dev);
300	if (ret)
301		goto out;
302
303	ret = br_sysfs_addbr(dev);
304	if (ret)
305		unregister_netdevice(dev);
306 out:
307	rtnl_unlock();
308	return ret;
309}
310
311int br_del_bridge(const char *name)
312{
313	struct net_device *dev;
314	int ret = 0;
315
316	rtnl_lock();
317	dev = __dev_get_by_name(name);
318	if (dev == NULL)
319		ret =  -ENXIO; 	/* Could not find device */
320
321	else if (!(dev->priv_flags & IFF_EBRIDGE)) {
322		/* Attempt to delete non bridge device! */
323		ret = -EPERM;
324	}
325
326	else if (dev->flags & IFF_UP) {
327		/* Not shutdown yet. */
328		ret = -EBUSY;
329	}
330
331	else
332		del_br(netdev_priv(dev));
333
334	rtnl_unlock();
335	return ret;
336}
337
338/* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
339int br_min_mtu(const struct net_bridge *br)
340{
341	const struct net_bridge_port *p;
342	int mtu = 0;
343
344	ASSERT_RTNL();
345
346	if (list_empty(&br->port_list))
347		mtu = ETH_DATA_LEN;
348	else {
349		list_for_each_entry(p, &br->port_list, list) {
350			if (!mtu  || p->dev->mtu < mtu)
351				mtu = p->dev->mtu;
352		}
353	}
354	return mtu;
355}
356
357/*
358 * Recomputes features using slave's features
359 */
360void br_features_recompute(struct net_bridge *br)
361{
362	struct net_bridge_port *p;
363	unsigned long features, checksum;
364
365	checksum = br->feature_mask & NETIF_F_ALL_CSUM ? NETIF_F_NO_CSUM : 0;
366	features = br->feature_mask & ~NETIF_F_ALL_CSUM;
367
368	list_for_each_entry(p, &br->port_list, list) {
369		unsigned long feature = p->dev->features;
370
371		if (checksum & NETIF_F_NO_CSUM && !(feature & NETIF_F_NO_CSUM))
372			checksum ^= NETIF_F_NO_CSUM | NETIF_F_HW_CSUM;
373		if (checksum & NETIF_F_HW_CSUM && !(feature & NETIF_F_HW_CSUM))
374			checksum ^= NETIF_F_HW_CSUM | NETIF_F_IP_CSUM;
375		if (!(feature & NETIF_F_IP_CSUM))
376			checksum = 0;
377
378		if (feature & NETIF_F_GSO)
379			feature |= NETIF_F_GSO_SOFTWARE;
380		feature |= NETIF_F_GSO;
381
382		features &= feature;
383	}
384
385	if (!(checksum & NETIF_F_ALL_CSUM))
386		features &= ~NETIF_F_SG;
387	if (!(features & NETIF_F_SG))
388		features &= ~NETIF_F_GSO_MASK;
389
390	br->dev->features = features | checksum | NETIF_F_LLTX |
391			    NETIF_F_GSO_ROBUST;
392}
393
394/* called with RTNL */
395int br_add_if(struct net_bridge *br, struct net_device *dev)
396{
397	struct net_bridge_port *p;
398	int err = 0;
399
400	if (dev->flags & IFF_LOOPBACK || dev->type != ARPHRD_ETHER)
401		return -EINVAL;
402
403	if (dev->hard_start_xmit == br_dev_xmit)
404		return -ELOOP;
405
406	if (dev->br_port != NULL)
407		return -EBUSY;
408
409	p = new_nbp(br, dev);
410	if (IS_ERR(p))
411		return PTR_ERR(p);
412
413	err = kobject_add(&p->kobj);
414	if (err)
415		goto err0;
416
417	err = br_fdb_insert(br, p, dev->dev_addr);
418	if (err)
419		goto err1;
420
421	err = br_sysfs_addif(p);
422	if (err)
423		goto err2;
424
425	rcu_assign_pointer(dev->br_port, p);
426	dev_set_promiscuity(dev, 1);
427
428	list_add_rcu(&p->list, &br->port_list);
429
430	spin_lock_bh(&br->lock);
431	br_stp_recalculate_bridge_id(br);
432	br_features_recompute(br);
433
434	if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
435	    (br->dev->flags & IFF_UP))
436		br_stp_enable_port(p);
437	spin_unlock_bh(&br->lock);
438
439	br_ifinfo_notify(RTM_NEWLINK, p);
440
441	dev_set_mtu(br->dev, br_min_mtu(br));
442
443	kobject_uevent(&p->kobj, KOBJ_ADD);
444
445	return 0;
446err2:
447	br_fdb_delete_by_port(br, p, 1);
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_each_netdev_safe(dev, nxt)
479		if (dev->priv_flags & IFF_EBRIDGE)
480			del_br(dev->priv);
481	rtnl_unlock();
482
483}
484