xref: /openbmc/linux/net/bridge/br_if.c (revision f42b3800)
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  * Since driver might sleep need to not be holding any locks.
33  */
34 static int port_cost(struct net_device *dev)
35 {
36 	if (dev->ethtool_ops && dev->ethtool_ops->get_settings) {
37 		struct ethtool_cmd ecmd = { .cmd = ETHTOOL_GSET, };
38 
39 		if (!dev->ethtool_ops->get_settings(dev, &ecmd)) {
40 			switch(ecmd.speed) {
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 
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 /*
65  * Check for port carrier transistions.
66  * Called from work queue to allow for calling functions that
67  * might sleep (such as speed check), and to debounce.
68  */
69 void br_port_carrier_check(struct net_bridge_port *p)
70 {
71 	struct net_device *dev = p->dev;
72 	struct net_bridge *br = p->br;
73 
74 	if (netif_carrier_ok(dev))
75 		p->path_cost = port_cost(dev);
76 
77 	if (netif_running(br->dev)) {
78 		spin_lock_bh(&br->lock);
79 		if (netif_carrier_ok(dev)) {
80 			if (p->state == BR_STATE_DISABLED)
81 				br_stp_enable_port(p);
82 		} else {
83 			if (p->state != BR_STATE_DISABLED)
84 				br_stp_disable_port(p);
85 		}
86 		spin_unlock_bh(&br->lock);
87 	}
88 }
89 
90 static void release_nbp(struct kobject *kobj)
91 {
92 	struct net_bridge_port *p
93 		= container_of(kobj, struct net_bridge_port, kobj);
94 	kfree(p);
95 }
96 
97 static struct kobj_type brport_ktype = {
98 #ifdef CONFIG_SYSFS
99 	.sysfs_ops = &brport_sysfs_ops,
100 #endif
101 	.release = release_nbp,
102 };
103 
104 static void destroy_nbp(struct net_bridge_port *p)
105 {
106 	struct net_device *dev = p->dev;
107 
108 	p->br = NULL;
109 	p->dev = NULL;
110 	dev_put(dev);
111 
112 	kobject_put(&p->kobj);
113 }
114 
115 static void destroy_nbp_rcu(struct rcu_head *head)
116 {
117 	struct net_bridge_port *p =
118 			container_of(head, struct net_bridge_port, rcu);
119 	destroy_nbp(p);
120 }
121 
122 /* Delete port(interface) from bridge is done in two steps.
123  * via RCU. First step, marks device as down. That deletes
124  * all the timers and stops new packets from flowing through.
125  *
126  * Final cleanup doesn't occur until after all CPU's finished
127  * processing packets.
128  *
129  * Protected from multiple admin operations by RTNL mutex
130  */
131 static void del_nbp(struct net_bridge_port *p)
132 {
133 	struct net_bridge *br = p->br;
134 	struct net_device *dev = p->dev;
135 
136 	sysfs_remove_link(br->ifobj, dev->name);
137 
138 	dev_set_promiscuity(dev, -1);
139 
140 	spin_lock_bh(&br->lock);
141 	br_stp_disable_port(p);
142 	spin_unlock_bh(&br->lock);
143 
144 	br_ifinfo_notify(RTM_DELLINK, p);
145 
146 	br_fdb_delete_by_port(br, p, 1);
147 
148 	list_del_rcu(&p->list);
149 
150 	rcu_assign_pointer(dev->br_port, NULL);
151 
152 	kobject_uevent(&p->kobj, KOBJ_REMOVE);
153 	kobject_del(&p->kobj);
154 
155 	call_rcu(&p->rcu, destroy_nbp_rcu);
156 }
157 
158 /* called with RTNL */
159 static void del_br(struct net_bridge *br)
160 {
161 	struct net_bridge_port *p, *n;
162 
163 	list_for_each_entry_safe(p, n, &br->port_list, list) {
164 		del_nbp(p);
165 	}
166 
167 	del_timer_sync(&br->gc_timer);
168 
169 	br_sysfs_delbr(br->dev);
170 	unregister_netdevice(br->dev);
171 }
172 
173 static struct net_device *new_bridge_dev(const char *name)
174 {
175 	struct net_bridge *br;
176 	struct net_device *dev;
177 
178 	dev = alloc_netdev(sizeof(struct net_bridge), name,
179 			   br_dev_setup);
180 
181 	if (!dev)
182 		return NULL;
183 
184 	br = netdev_priv(dev);
185 	br->dev = dev;
186 
187 	spin_lock_init(&br->lock);
188 	INIT_LIST_HEAD(&br->port_list);
189 	spin_lock_init(&br->hash_lock);
190 
191 	br->bridge_id.prio[0] = 0x80;
192 	br->bridge_id.prio[1] = 0x00;
193 
194 	memcpy(br->group_addr, br_group_address, ETH_ALEN);
195 
196 	br->feature_mask = dev->features;
197 	br->stp_enabled = BR_NO_STP;
198 	br->designated_root = br->bridge_id;
199 	br->root_path_cost = 0;
200 	br->root_port = 0;
201 	br->bridge_max_age = br->max_age = 20 * HZ;
202 	br->bridge_hello_time = br->hello_time = 2 * HZ;
203 	br->bridge_forward_delay = br->forward_delay = 15 * HZ;
204 	br->topology_change = 0;
205 	br->topology_change_detected = 0;
206 	br->ageing_time = 300 * HZ;
207 	INIT_LIST_HEAD(&br->age_list);
208 
209 	br_stp_timer_init(br);
210 
211 	return dev;
212 }
213 
214 /* find an available port number */
215 static int find_portno(struct net_bridge *br)
216 {
217 	int index;
218 	struct net_bridge_port *p;
219 	unsigned long *inuse;
220 
221 	inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
222 			GFP_KERNEL);
223 	if (!inuse)
224 		return -ENOMEM;
225 
226 	set_bit(0, inuse);	/* zero is reserved */
227 	list_for_each_entry(p, &br->port_list, list) {
228 		set_bit(p->port_no, inuse);
229 	}
230 	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
231 	kfree(inuse);
232 
233 	return (index >= BR_MAX_PORTS) ? -EXFULL : index;
234 }
235 
236 /* called with RTNL but without bridge lock */
237 static struct net_bridge_port *new_nbp(struct net_bridge *br,
238 				       struct net_device *dev)
239 {
240 	int index;
241 	struct net_bridge_port *p;
242 
243 	index = find_portno(br);
244 	if (index < 0)
245 		return ERR_PTR(index);
246 
247 	p = kzalloc(sizeof(*p), GFP_KERNEL);
248 	if (p == NULL)
249 		return ERR_PTR(-ENOMEM);
250 
251 	p->br = br;
252 	dev_hold(dev);
253 	p->dev = dev;
254 	p->path_cost = port_cost(dev);
255 	p->priority = 0x8000 >> BR_PORT_BITS;
256 	p->port_no = index;
257 	br_init_port(p);
258 	p->state = BR_STATE_DISABLED;
259 	br_stp_port_timer_init(p);
260 
261 	return p;
262 }
263 
264 int br_add_bridge(const char *name)
265 {
266 	struct net_device *dev;
267 	int ret;
268 
269 	dev = new_bridge_dev(name);
270 	if (!dev)
271 		return -ENOMEM;
272 
273 	rtnl_lock();
274 	if (strchr(dev->name, '%')) {
275 		ret = dev_alloc_name(dev, dev->name);
276 		if (ret < 0) {
277 			free_netdev(dev);
278 			goto out;
279 		}
280 	}
281 
282 	ret = register_netdevice(dev);
283 	if (ret)
284 		goto out;
285 
286 	ret = br_sysfs_addbr(dev);
287 	if (ret)
288 		unregister_netdevice(dev);
289  out:
290 	rtnl_unlock();
291 	return ret;
292 }
293 
294 int br_del_bridge(const char *name)
295 {
296 	struct net_device *dev;
297 	int ret = 0;
298 
299 	rtnl_lock();
300 	dev = __dev_get_by_name(&init_net, name);
301 	if (dev == NULL)
302 		ret =  -ENXIO; 	/* Could not find device */
303 
304 	else if (!(dev->priv_flags & IFF_EBRIDGE)) {
305 		/* Attempt to delete non bridge device! */
306 		ret = -EPERM;
307 	}
308 
309 	else if (dev->flags & IFF_UP) {
310 		/* Not shutdown yet. */
311 		ret = -EBUSY;
312 	}
313 
314 	else
315 		del_br(netdev_priv(dev));
316 
317 	rtnl_unlock();
318 	return ret;
319 }
320 
321 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
322 int br_min_mtu(const struct net_bridge *br)
323 {
324 	const struct net_bridge_port *p;
325 	int mtu = 0;
326 
327 	ASSERT_RTNL();
328 
329 	if (list_empty(&br->port_list))
330 		mtu = ETH_DATA_LEN;
331 	else {
332 		list_for_each_entry(p, &br->port_list, list) {
333 			if (!mtu  || p->dev->mtu < mtu)
334 				mtu = p->dev->mtu;
335 		}
336 	}
337 	return mtu;
338 }
339 
340 /*
341  * Recomputes features using slave's features
342  */
343 void br_features_recompute(struct net_bridge *br)
344 {
345 	struct net_bridge_port *p;
346 	unsigned long features;
347 
348 	features = br->feature_mask;
349 
350 	list_for_each_entry(p, &br->port_list, list) {
351 		features = netdev_compute_features(features, p->dev->features);
352 	}
353 
354 	br->dev->features = features;
355 }
356 
357 /* called with RTNL */
358 int br_add_if(struct net_bridge *br, struct net_device *dev)
359 {
360 	struct net_bridge_port *p;
361 	int err = 0;
362 
363 	if (dev->flags & IFF_LOOPBACK || dev->type != ARPHRD_ETHER)
364 		return -EINVAL;
365 
366 	if (dev->hard_start_xmit == br_dev_xmit)
367 		return -ELOOP;
368 
369 	if (dev->br_port != NULL)
370 		return -EBUSY;
371 
372 	p = new_nbp(br, dev);
373 	if (IS_ERR(p))
374 		return PTR_ERR(p);
375 
376 	err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
377 				   SYSFS_BRIDGE_PORT_ATTR);
378 	if (err)
379 		goto err0;
380 
381 	err = br_fdb_insert(br, p, dev->dev_addr);
382 	if (err)
383 		goto err1;
384 
385 	err = br_sysfs_addif(p);
386 	if (err)
387 		goto err2;
388 
389 	rcu_assign_pointer(dev->br_port, p);
390 	dev_set_promiscuity(dev, 1);
391 
392 	list_add_rcu(&p->list, &br->port_list);
393 
394 	spin_lock_bh(&br->lock);
395 	br_stp_recalculate_bridge_id(br);
396 	br_features_recompute(br);
397 
398 	if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
399 	    (br->dev->flags & IFF_UP))
400 		br_stp_enable_port(p);
401 	spin_unlock_bh(&br->lock);
402 
403 	br_ifinfo_notify(RTM_NEWLINK, p);
404 
405 	dev_set_mtu(br->dev, br_min_mtu(br));
406 
407 	kobject_uevent(&p->kobj, KOBJ_ADD);
408 
409 	return 0;
410 err2:
411 	br_fdb_delete_by_port(br, p, 1);
412 err1:
413 	kobject_del(&p->kobj);
414 	return err;
415 err0:
416 	kobject_put(&p->kobj);
417 	return err;
418 }
419 
420 /* called with RTNL */
421 int br_del_if(struct net_bridge *br, struct net_device *dev)
422 {
423 	struct net_bridge_port *p = dev->br_port;
424 
425 	if (!p || p->br != br)
426 		return -EINVAL;
427 
428 	del_nbp(p);
429 
430 	spin_lock_bh(&br->lock);
431 	br_stp_recalculate_bridge_id(br);
432 	br_features_recompute(br);
433 	spin_unlock_bh(&br->lock);
434 
435 	return 0;
436 }
437 
438 void __exit br_cleanup_bridges(void)
439 {
440 	struct net_device *dev, *nxt;
441 
442 	rtnl_lock();
443 	for_each_netdev_safe(&init_net, dev, nxt)
444 		if (dev->priv_flags & IFF_EBRIDGE)
445 			del_br(dev->priv);
446 	rtnl_unlock();
447 
448 }
449