xref: /openbmc/linux/net/bridge/br_if.c (revision d3597236) 
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  */
36 static 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 transitions. */
65 void 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 (!(p->flags & BR_ADMIN_COST) &&
71 	    netif_running(dev) && netif_oper_up(dev))
72 		p->path_cost = port_cost(dev);
73 
74 	if (!netif_running(br->dev))
75 		return;
76 
77 	spin_lock_bh(&br->lock);
78 	if (netif_running(dev) && netif_oper_up(dev)) {
79 		if (p->state == BR_STATE_DISABLED)
80 			br_stp_enable_port(p);
81 	} else {
82 		if (p->state != BR_STATE_DISABLED)
83 			br_stp_disable_port(p);
84 	}
85 	spin_unlock_bh(&br->lock);
86 }
87 
88 static void br_port_set_promisc(struct net_bridge_port *p)
89 {
90 	int err = 0;
91 
92 	if (br_promisc_port(p))
93 		return;
94 
95 	err = dev_set_promiscuity(p->dev, 1);
96 	if (err)
97 		return;
98 
99 	br_fdb_unsync_static(p->br, p);
100 	p->flags |= BR_PROMISC;
101 }
102 
103 static void br_port_clear_promisc(struct net_bridge_port *p)
104 {
105 	int err;
106 
107 	/* Check if the port is already non-promisc or if it doesn't
108 	 * support UNICAST filtering.  Without unicast filtering support
109 	 * we'll end up re-enabling promisc mode anyway, so just check for
110 	 * it here.
111 	 */
112 	if (!br_promisc_port(p) || !(p->dev->priv_flags & IFF_UNICAST_FLT))
113 		return;
114 
115 	/* Since we'll be clearing the promisc mode, program the port
116 	 * first so that we don't have interruption in traffic.
117 	 */
118 	err = br_fdb_sync_static(p->br, p);
119 	if (err)
120 		return;
121 
122 	dev_set_promiscuity(p->dev, -1);
123 	p->flags &= ~BR_PROMISC;
124 }
125 
126 /* When a port is added or removed or when certain port flags
127  * change, this function is called to automatically manage
128  * promiscuity setting of all the bridge ports.  We are always called
129  * under RTNL so can skip using rcu primitives.
130  */
131 void br_manage_promisc(struct net_bridge *br)
132 {
133 	struct net_bridge_port *p;
134 	bool set_all = false;
135 
136 	/* If vlan filtering is disabled or bridge interface is placed
137 	 * into promiscuous mode, place all ports in promiscuous mode.
138 	 */
139 	if ((br->dev->flags & IFF_PROMISC) || !br_vlan_enabled(br))
140 		set_all = true;
141 
142 	list_for_each_entry(p, &br->port_list, list) {
143 		if (set_all) {
144 			br_port_set_promisc(p);
145 		} else {
146 			/* If the number of auto-ports is <= 1, then all other
147 			 * ports will have their output configuration
148 			 * statically specified through fdbs.  Since ingress
149 			 * on the auto-port becomes forwarding/egress to other
150 			 * ports and egress configuration is statically known,
151 			 * we can say that ingress configuration of the
152 			 * auto-port is also statically known.
153 			 * This lets us disable promiscuous mode and write
154 			 * this config to hw.
155 			 */
156 			if (br->auto_cnt == 0 ||
157 			    (br->auto_cnt == 1 && br_auto_port(p)))
158 				br_port_clear_promisc(p);
159 			else
160 				br_port_set_promisc(p);
161 		}
162 	}
163 }
164 
165 static void nbp_update_port_count(struct net_bridge *br)
166 {
167 	struct net_bridge_port *p;
168 	u32 cnt = 0;
169 
170 	list_for_each_entry(p, &br->port_list, list) {
171 		if (br_auto_port(p))
172 			cnt++;
173 	}
174 	if (br->auto_cnt != cnt) {
175 		br->auto_cnt = cnt;
176 		br_manage_promisc(br);
177 	}
178 }
179 
180 static void nbp_delete_promisc(struct net_bridge_port *p)
181 {
182 	/* If port is currently promiscuous, unset promiscuity.
183 	 * Otherwise, it is a static port so remove all addresses
184 	 * from it.
185 	 */
186 	dev_set_allmulti(p->dev, -1);
187 	if (br_promisc_port(p))
188 		dev_set_promiscuity(p->dev, -1);
189 	else
190 		br_fdb_unsync_static(p->br, p);
191 }
192 
193 static void release_nbp(struct kobject *kobj)
194 {
195 	struct net_bridge_port *p
196 		= container_of(kobj, struct net_bridge_port, kobj);
197 	kfree(p);
198 }
199 
200 static struct kobj_type brport_ktype = {
201 #ifdef CONFIG_SYSFS
202 	.sysfs_ops = &brport_sysfs_ops,
203 #endif
204 	.release = release_nbp,
205 };
206 
207 static void destroy_nbp(struct net_bridge_port *p)
208 {
209 	struct net_device *dev = p->dev;
210 
211 	p->br = NULL;
212 	p->dev = NULL;
213 	dev_put(dev);
214 
215 	kobject_put(&p->kobj);
216 }
217 
218 static void destroy_nbp_rcu(struct rcu_head *head)
219 {
220 	struct net_bridge_port *p =
221 			container_of(head, struct net_bridge_port, rcu);
222 	destroy_nbp(p);
223 }
224 
225 /* Delete port(interface) from bridge is done in two steps.
226  * via RCU. First step, marks device as down. That deletes
227  * all the timers and stops new packets from flowing through.
228  *
229  * Final cleanup doesn't occur until after all CPU's finished
230  * processing packets.
231  *
232  * Protected from multiple admin operations by RTNL mutex
233  */
234 static void del_nbp(struct net_bridge_port *p)
235 {
236 	struct net_bridge *br = p->br;
237 	struct net_device *dev = p->dev;
238 
239 	sysfs_remove_link(br->ifobj, p->dev->name);
240 
241 	nbp_delete_promisc(p);
242 
243 	spin_lock_bh(&br->lock);
244 	br_stp_disable_port(p);
245 	spin_unlock_bh(&br->lock);
246 
247 	br_ifinfo_notify(RTM_DELLINK, p);
248 
249 	list_del_rcu(&p->list);
250 
251 	nbp_vlan_flush(p);
252 	br_fdb_delete_by_port(br, p, 0, 1);
253 	nbp_update_port_count(br);
254 
255 	netdev_upper_dev_unlink(dev, br->dev);
256 
257 	dev->priv_flags &= ~IFF_BRIDGE_PORT;
258 
259 	netdev_rx_handler_unregister(dev);
260 
261 	br_multicast_del_port(p);
262 
263 	kobject_uevent(&p->kobj, KOBJ_REMOVE);
264 	kobject_del(&p->kobj);
265 
266 	br_netpoll_disable(p);
267 
268 	call_rcu(&p->rcu, destroy_nbp_rcu);
269 }
270 
271 /* Delete bridge device */
272 void br_dev_delete(struct net_device *dev, struct list_head *head)
273 {
274 	struct net_bridge *br = netdev_priv(dev);
275 	struct net_bridge_port *p, *n;
276 
277 	list_for_each_entry_safe(p, n, &br->port_list, list) {
278 		del_nbp(p);
279 	}
280 
281 	br_fdb_delete_by_port(br, NULL, 0, 1);
282 
283 	br_vlan_flush(br);
284 	del_timer_sync(&br->gc_timer);
285 
286 	br_sysfs_delbr(br->dev);
287 	unregister_netdevice_queue(br->dev, head);
288 }
289 
290 /* find an available port number */
291 static int find_portno(struct net_bridge *br)
292 {
293 	int index;
294 	struct net_bridge_port *p;
295 	unsigned long *inuse;
296 
297 	inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
298 			GFP_KERNEL);
299 	if (!inuse)
300 		return -ENOMEM;
301 
302 	set_bit(0, inuse);	/* zero is reserved */
303 	list_for_each_entry(p, &br->port_list, list) {
304 		set_bit(p->port_no, inuse);
305 	}
306 	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
307 	kfree(inuse);
308 
309 	return (index >= BR_MAX_PORTS) ? -EXFULL : index;
310 }
311 
312 /* called with RTNL but without bridge lock */
313 static struct net_bridge_port *new_nbp(struct net_bridge *br,
314 				       struct net_device *dev)
315 {
316 	int index;
317 	struct net_bridge_port *p;
318 
319 	index = find_portno(br);
320 	if (index < 0)
321 		return ERR_PTR(index);
322 
323 	p = kzalloc(sizeof(*p), GFP_KERNEL);
324 	if (p == NULL)
325 		return ERR_PTR(-ENOMEM);
326 
327 	p->br = br;
328 	dev_hold(dev);
329 	p->dev = dev;
330 	p->path_cost = port_cost(dev);
331 	p->priority = 0x8000 >> BR_PORT_BITS;
332 	p->port_no = index;
333 	p->flags = BR_LEARNING | BR_FLOOD;
334 	br_init_port(p);
335 	br_set_state(p, BR_STATE_DISABLED);
336 	br_stp_port_timer_init(p);
337 	br_multicast_add_port(p);
338 
339 	return p;
340 }
341 
342 int br_add_bridge(struct net *net, const char *name)
343 {
344 	struct net_device *dev;
345 	int res;
346 
347 	dev = alloc_netdev(sizeof(struct net_bridge), name, NET_NAME_UNKNOWN,
348 			   br_dev_setup);
349 
350 	if (!dev)
351 		return -ENOMEM;
352 
353 	dev_net_set(dev, net);
354 	dev->rtnl_link_ops = &br_link_ops;
355 
356 	res = register_netdev(dev);
357 	if (res)
358 		free_netdev(dev);
359 	return res;
360 }
361 
362 int br_del_bridge(struct net *net, const char *name)
363 {
364 	struct net_device *dev;
365 	int ret = 0;
366 
367 	rtnl_lock();
368 	dev = __dev_get_by_name(net, name);
369 	if (dev == NULL)
370 		ret =  -ENXIO; 	/* Could not find device */
371 
372 	else if (!(dev->priv_flags & IFF_EBRIDGE)) {
373 		/* Attempt to delete non bridge device! */
374 		ret = -EPERM;
375 	}
376 
377 	else if (dev->flags & IFF_UP) {
378 		/* Not shutdown yet. */
379 		ret = -EBUSY;
380 	}
381 
382 	else
383 		br_dev_delete(dev, NULL);
384 
385 	rtnl_unlock();
386 	return ret;
387 }
388 
389 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
390 int br_min_mtu(const struct net_bridge *br)
391 {
392 	const struct net_bridge_port *p;
393 	int mtu = 0;
394 
395 	ASSERT_RTNL();
396 
397 	if (list_empty(&br->port_list))
398 		mtu = ETH_DATA_LEN;
399 	else {
400 		list_for_each_entry(p, &br->port_list, list) {
401 			if (!mtu  || p->dev->mtu < mtu)
402 				mtu = p->dev->mtu;
403 		}
404 	}
405 	return mtu;
406 }
407 
408 /*
409  * Recomputes features using slave's features
410  */
411 netdev_features_t br_features_recompute(struct net_bridge *br,
412 	netdev_features_t features)
413 {
414 	struct net_bridge_port *p;
415 	netdev_features_t mask;
416 
417 	if (list_empty(&br->port_list))
418 		return features;
419 
420 	mask = features;
421 	features &= ~NETIF_F_ONE_FOR_ALL;
422 
423 	list_for_each_entry(p, &br->port_list, list) {
424 		features = netdev_increment_features(features,
425 						     p->dev->features, mask);
426 	}
427 	features = netdev_add_tso_features(features, mask);
428 
429 	return features;
430 }
431 
432 /* called with RTNL */
433 int br_add_if(struct net_bridge *br, struct net_device *dev)
434 {
435 	struct net_bridge_port *p;
436 	int err = 0;
437 	bool changed_addr;
438 
439 	/* Don't allow bridging non-ethernet like devices, or DSA-enabled
440 	 * master network devices since the bridge layer rx_handler prevents
441 	 * the DSA fake ethertype handler to be invoked, so we do not strip off
442 	 * the DSA switch tag protocol header and the bridge layer just return
443 	 * RX_HANDLER_CONSUMED, stopping RX processing for these frames.
444 	 */
445 	if ((dev->flags & IFF_LOOPBACK) ||
446 	    dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
447 	    !is_valid_ether_addr(dev->dev_addr) ||
448 	    netdev_uses_dsa(dev))
449 		return -EINVAL;
450 
451 	/* No bridging of bridges */
452 	if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
453 		return -ELOOP;
454 
455 	/* Device is already being bridged */
456 	if (br_port_exists(dev))
457 		return -EBUSY;
458 
459 	/* No bridging devices that dislike that (e.g. wireless) */
460 	if (dev->priv_flags & IFF_DONT_BRIDGE)
461 		return -EOPNOTSUPP;
462 
463 	p = new_nbp(br, dev);
464 	if (IS_ERR(p))
465 		return PTR_ERR(p);
466 
467 	call_netdevice_notifiers(NETDEV_JOIN, dev);
468 
469 	err = dev_set_allmulti(dev, 1);
470 	if (err)
471 		goto put_back;
472 
473 	err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
474 				   SYSFS_BRIDGE_PORT_ATTR);
475 	if (err)
476 		goto err1;
477 
478 	err = br_sysfs_addif(p);
479 	if (err)
480 		goto err2;
481 
482 	err = br_netpoll_enable(p);
483 	if (err)
484 		goto err3;
485 
486 	err = netdev_rx_handler_register(dev, br_handle_frame, p);
487 	if (err)
488 		goto err4;
489 
490 	dev->priv_flags |= IFF_BRIDGE_PORT;
491 
492 	err = netdev_master_upper_dev_link(dev, br->dev);
493 	if (err)
494 		goto err5;
495 
496 	dev_disable_lro(dev);
497 
498 	list_add_rcu(&p->list, &br->port_list);
499 
500 	nbp_update_port_count(br);
501 
502 	netdev_update_features(br->dev);
503 
504 	if (br->dev->needed_headroom < dev->needed_headroom)
505 		br->dev->needed_headroom = dev->needed_headroom;
506 
507 	if (br_fdb_insert(br, p, dev->dev_addr, 0))
508 		netdev_err(dev, "failed insert local address bridge forwarding table\n");
509 
510 	if (nbp_vlan_init(p))
511 		netdev_err(dev, "failed to initialize vlan filtering on this port\n");
512 
513 	spin_lock_bh(&br->lock);
514 	changed_addr = br_stp_recalculate_bridge_id(br);
515 
516 	if (netif_running(dev) && netif_oper_up(dev) &&
517 	    (br->dev->flags & IFF_UP))
518 		br_stp_enable_port(p);
519 	spin_unlock_bh(&br->lock);
520 
521 	br_ifinfo_notify(RTM_NEWLINK, p);
522 
523 	if (changed_addr)
524 		call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
525 
526 	dev_set_mtu(br->dev, br_min_mtu(br));
527 
528 	kobject_uevent(&p->kobj, KOBJ_ADD);
529 
530 	return 0;
531 
532 err5:
533 	dev->priv_flags &= ~IFF_BRIDGE_PORT;
534 	netdev_rx_handler_unregister(dev);
535 err4:
536 	br_netpoll_disable(p);
537 err3:
538 	sysfs_remove_link(br->ifobj, p->dev->name);
539 err2:
540 	kobject_put(&p->kobj);
541 	p = NULL; /* kobject_put frees */
542 err1:
543 	dev_set_allmulti(dev, -1);
544 put_back:
545 	dev_put(dev);
546 	kfree(p);
547 	return err;
548 }
549 
550 /* called with RTNL */
551 int br_del_if(struct net_bridge *br, struct net_device *dev)
552 {
553 	struct net_bridge_port *p;
554 	bool changed_addr;
555 
556 	p = br_port_get_rtnl(dev);
557 	if (!p || p->br != br)
558 		return -EINVAL;
559 
560 	/* Since more than one interface can be attached to a bridge,
561 	 * there still maybe an alternate path for netconsole to use;
562 	 * therefore there is no reason for a NETDEV_RELEASE event.
563 	 */
564 	del_nbp(p);
565 
566 	dev_set_mtu(br->dev, br_min_mtu(br));
567 
568 	spin_lock_bh(&br->lock);
569 	changed_addr = br_stp_recalculate_bridge_id(br);
570 	spin_unlock_bh(&br->lock);
571 
572 	if (changed_addr)
573 		call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
574 
575 	netdev_update_features(br->dev);
576 
577 	return 0;
578 }
579 
580 void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
581 {
582 	struct net_bridge *br = p->br;
583 
584 	if (mask & BR_AUTO_MASK)
585 		nbp_update_port_count(br);
586 }
587