• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 #include <net/switchdev.h>
28 
29 #include "br_private.h"
30 
31 /*
32  * Determine initial path cost based on speed.
33  * using recommendations from 802.1d standard
34  *
35  * Since driver might sleep need to not be holding any locks.
36  */
port_cost(struct net_device * dev)37 static int port_cost(struct net_device *dev)
38 {
39 	struct ethtool_link_ksettings ecmd;
40 
41 	if (!__ethtool_get_link_ksettings(dev, &ecmd)) {
42 		switch (ecmd.base.speed) {
43 		case SPEED_10000:
44 			return 2;
45 		case SPEED_1000:
46 			return 4;
47 		case SPEED_100:
48 			return 19;
49 		case SPEED_10:
50 			return 100;
51 		}
52 	}
53 
54 	/* Old silly heuristics based on name */
55 	if (!strncmp(dev->name, "lec", 3))
56 		return 7;
57 
58 	if (!strncmp(dev->name, "plip", 4))
59 		return 2500;
60 
61 	return 100;	/* assume old 10Mbps */
62 }
63 
64 
65 /* Check for port carrier transitions. */
br_port_carrier_check(struct net_bridge_port * p)66 void br_port_carrier_check(struct net_bridge_port *p)
67 {
68 	struct net_device *dev = p->dev;
69 	struct net_bridge *br = p->br;
70 
71 	if (!(p->flags & BR_ADMIN_COST) &&
72 	    netif_running(dev) && netif_oper_up(dev))
73 		p->path_cost = port_cost(dev);
74 
75 	if (!netif_running(br->dev))
76 		return;
77 
78 	spin_lock_bh(&br->lock);
79 	if (netif_running(dev) && netif_oper_up(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 
br_port_set_promisc(struct net_bridge_port * p)89 static void br_port_set_promisc(struct net_bridge_port *p)
90 {
91 	int err = 0;
92 
93 	if (br_promisc_port(p))
94 		return;
95 
96 	err = dev_set_promiscuity(p->dev, 1);
97 	if (err)
98 		return;
99 
100 	br_fdb_unsync_static(p->br, p);
101 	p->flags |= BR_PROMISC;
102 }
103 
br_port_clear_promisc(struct net_bridge_port * p)104 static void br_port_clear_promisc(struct net_bridge_port *p)
105 {
106 	int err;
107 
108 	/* Check if the port is already non-promisc or if it doesn't
109 	 * support UNICAST filtering.  Without unicast filtering support
110 	 * we'll end up re-enabling promisc mode anyway, so just check for
111 	 * it here.
112 	 */
113 	if (!br_promisc_port(p) || !(p->dev->priv_flags & IFF_UNICAST_FLT))
114 		return;
115 
116 	/* Since we'll be clearing the promisc mode, program the port
117 	 * first so that we don't have interruption in traffic.
118 	 */
119 	err = br_fdb_sync_static(p->br, p);
120 	if (err)
121 		return;
122 
123 	dev_set_promiscuity(p->dev, -1);
124 	p->flags &= ~BR_PROMISC;
125 }
126 
127 /* When a port is added or removed or when certain port flags
128  * change, this function is called to automatically manage
129  * promiscuity setting of all the bridge ports.  We are always called
130  * under RTNL so can skip using rcu primitives.
131  */
br_manage_promisc(struct net_bridge * br)132 void br_manage_promisc(struct net_bridge *br)
133 {
134 	struct net_bridge_port *p;
135 	bool set_all = false;
136 
137 	/* If vlan filtering is disabled or bridge interface is placed
138 	 * into promiscuous mode, place all ports in promiscuous mode.
139 	 */
140 	if ((br->dev->flags & IFF_PROMISC) || !br_vlan_enabled(br))
141 		set_all = true;
142 
143 	list_for_each_entry(p, &br->port_list, list) {
144 		if (set_all) {
145 			br_port_set_promisc(p);
146 		} else {
147 			/* If the number of auto-ports is <= 1, then all other
148 			 * ports will have their output configuration
149 			 * statically specified through fdbs.  Since ingress
150 			 * on the auto-port becomes forwarding/egress to other
151 			 * ports and egress configuration is statically known,
152 			 * we can say that ingress configuration of the
153 			 * auto-port is also statically known.
154 			 * This lets us disable promiscuous mode and write
155 			 * this config to hw.
156 			 */
157 			if (br->auto_cnt == 0 ||
158 			    (br->auto_cnt == 1 && br_auto_port(p)))
159 				br_port_clear_promisc(p);
160 			else
161 				br_port_set_promisc(p);
162 		}
163 	}
164 }
165 
nbp_update_port_count(struct net_bridge * br)166 static void nbp_update_port_count(struct net_bridge *br)
167 {
168 	struct net_bridge_port *p;
169 	u32 cnt = 0;
170 
171 	list_for_each_entry(p, &br->port_list, list) {
172 		if (br_auto_port(p))
173 			cnt++;
174 	}
175 	if (br->auto_cnt != cnt) {
176 		br->auto_cnt = cnt;
177 		br_manage_promisc(br);
178 	}
179 }
180 
nbp_delete_promisc(struct net_bridge_port * p)181 static void nbp_delete_promisc(struct net_bridge_port *p)
182 {
183 	/* If port is currently promiscuous, unset promiscuity.
184 	 * Otherwise, it is a static port so remove all addresses
185 	 * from it.
186 	 */
187 	dev_set_allmulti(p->dev, -1);
188 	if (br_promisc_port(p))
189 		dev_set_promiscuity(p->dev, -1);
190 	else
191 		br_fdb_unsync_static(p->br, p);
192 }
193 
release_nbp(struct kobject * kobj)194 static void release_nbp(struct kobject *kobj)
195 {
196 	struct net_bridge_port *p
197 		= container_of(kobj, struct net_bridge_port, kobj);
198 	kfree(p);
199 }
200 
201 static struct kobj_type brport_ktype = {
202 #ifdef CONFIG_SYSFS
203 	.sysfs_ops = &brport_sysfs_ops,
204 #endif
205 	.release = release_nbp,
206 };
207 
destroy_nbp(struct net_bridge_port * p)208 static void destroy_nbp(struct net_bridge_port *p)
209 {
210 	struct net_device *dev = p->dev;
211 
212 	p->br = NULL;
213 	p->dev = NULL;
214 	dev_put(dev);
215 
216 	kobject_put(&p->kobj);
217 }
218 
destroy_nbp_rcu(struct rcu_head * head)219 static void destroy_nbp_rcu(struct rcu_head *head)
220 {
221 	struct net_bridge_port *p =
222 			container_of(head, struct net_bridge_port, rcu);
223 	destroy_nbp(p);
224 }
225 
get_max_headroom(struct net_bridge * br)226 static unsigned get_max_headroom(struct net_bridge *br)
227 {
228 	unsigned max_headroom = 0;
229 	struct net_bridge_port *p;
230 
231 	list_for_each_entry(p, &br->port_list, list) {
232 		unsigned dev_headroom = netdev_get_fwd_headroom(p->dev);
233 
234 		if (dev_headroom > max_headroom)
235 			max_headroom = dev_headroom;
236 	}
237 
238 	return max_headroom;
239 }
240 
update_headroom(struct net_bridge * br,int new_hr)241 static void update_headroom(struct net_bridge *br, int new_hr)
242 {
243 	struct net_bridge_port *p;
244 
245 	list_for_each_entry(p, &br->port_list, list)
246 		netdev_set_rx_headroom(p->dev, new_hr);
247 
248 	br->dev->needed_headroom = new_hr;
249 }
250 
251 /* Delete port(interface) from bridge is done in two steps.
252  * via RCU. First step, marks device as down. That deletes
253  * all the timers and stops new packets from flowing through.
254  *
255  * Final cleanup doesn't occur until after all CPU's finished
256  * processing packets.
257  *
258  * Protected from multiple admin operations by RTNL mutex
259  */
del_nbp(struct net_bridge_port * p)260 static void del_nbp(struct net_bridge_port *p)
261 {
262 	struct net_bridge *br = p->br;
263 	struct net_device *dev = p->dev;
264 
265 	sysfs_remove_link(br->ifobj, p->dev->name);
266 
267 	nbp_delete_promisc(p);
268 
269 	spin_lock_bh(&br->lock);
270 	br_stp_disable_port(p);
271 	spin_unlock_bh(&br->lock);
272 
273 	br_ifinfo_notify(RTM_DELLINK, p);
274 
275 	list_del_rcu(&p->list);
276 	if (netdev_get_fwd_headroom(dev) == br->dev->needed_headroom)
277 		update_headroom(br, get_max_headroom(br));
278 	netdev_reset_rx_headroom(dev);
279 
280 	nbp_vlan_flush(p);
281 	br_fdb_delete_by_port(br, p, 0, 1);
282 	switchdev_deferred_process();
283 
284 	nbp_update_port_count(br);
285 
286 	netdev_upper_dev_unlink(dev, br->dev);
287 
288 	dev->priv_flags &= ~IFF_BRIDGE_PORT;
289 
290 	netdev_rx_handler_unregister(dev);
291 
292 	br_multicast_del_port(p);
293 
294 	kobject_uevent(&p->kobj, KOBJ_REMOVE);
295 	kobject_del(&p->kobj);
296 
297 	br_netpoll_disable(p);
298 
299 	call_rcu(&p->rcu, destroy_nbp_rcu);
300 }
301 
302 /* Delete bridge device */
br_dev_delete(struct net_device * dev,struct list_head * head)303 void br_dev_delete(struct net_device *dev, struct list_head *head)
304 {
305 	struct net_bridge *br = netdev_priv(dev);
306 	struct net_bridge_port *p, *n;
307 
308 	list_for_each_entry_safe(p, n, &br->port_list, list) {
309 		del_nbp(p);
310 	}
311 
312 	br_fdb_delete_by_port(br, NULL, 0, 1);
313 
314 	br_vlan_flush(br);
315 	br_multicast_dev_del(br);
316 	del_timer_sync(&br->gc_timer);
317 
318 	br_sysfs_delbr(br->dev);
319 	unregister_netdevice_queue(br->dev, head);
320 }
321 
322 /* find an available port number */
find_portno(struct net_bridge * br)323 static int find_portno(struct net_bridge *br)
324 {
325 	int index;
326 	struct net_bridge_port *p;
327 	unsigned long *inuse;
328 
329 	inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
330 			GFP_KERNEL);
331 	if (!inuse)
332 		return -ENOMEM;
333 
334 	set_bit(0, inuse);	/* zero is reserved */
335 	list_for_each_entry(p, &br->port_list, list) {
336 		set_bit(p->port_no, inuse);
337 	}
338 	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
339 	kfree(inuse);
340 
341 	return (index >= BR_MAX_PORTS) ? -EXFULL : index;
342 }
343 
344 /* called with RTNL but without bridge lock */
new_nbp(struct net_bridge * br,struct net_device * dev)345 static struct net_bridge_port *new_nbp(struct net_bridge *br,
346 				       struct net_device *dev)
347 {
348 	struct net_bridge_port *p;
349 	int index, err;
350 
351 	index = find_portno(br);
352 	if (index < 0)
353 		return ERR_PTR(index);
354 
355 	p = kzalloc(sizeof(*p), GFP_KERNEL);
356 	if (p == NULL)
357 		return ERR_PTR(-ENOMEM);
358 
359 	p->br = br;
360 	dev_hold(dev);
361 	p->dev = dev;
362 	p->path_cost = port_cost(dev);
363 	p->priority = 0x8000 >> BR_PORT_BITS;
364 	p->port_no = index;
365 	p->flags = BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD;
366 	br_init_port(p);
367 	br_set_state(p, BR_STATE_DISABLED);
368 	br_stp_port_timer_init(p);
369 	err = br_multicast_add_port(p);
370 	if (err) {
371 		dev_put(dev);
372 		kfree(p);
373 		p = ERR_PTR(err);
374 	}
375 
376 	return p;
377 }
378 
br_add_bridge(struct net * net,const char * name)379 int br_add_bridge(struct net *net, const char *name)
380 {
381 	struct net_device *dev;
382 	int res;
383 
384 	dev = alloc_netdev(sizeof(struct net_bridge), name, NET_NAME_UNKNOWN,
385 			   br_dev_setup);
386 
387 	if (!dev)
388 		return -ENOMEM;
389 
390 	dev_net_set(dev, net);
391 	dev->rtnl_link_ops = &br_link_ops;
392 
393 	res = register_netdev(dev);
394 	if (res)
395 		free_netdev(dev);
396 	return res;
397 }
398 
br_del_bridge(struct net * net,const char * name)399 int br_del_bridge(struct net *net, const char *name)
400 {
401 	struct net_device *dev;
402 	int ret = 0;
403 
404 	rtnl_lock();
405 	dev = __dev_get_by_name(net, name);
406 	if (dev == NULL)
407 		ret =  -ENXIO; 	/* Could not find device */
408 
409 	else if (!(dev->priv_flags & IFF_EBRIDGE)) {
410 		/* Attempt to delete non bridge device! */
411 		ret = -EPERM;
412 	}
413 
414 	else if (dev->flags & IFF_UP) {
415 		/* Not shutdown yet. */
416 		ret = -EBUSY;
417 	}
418 
419 	else
420 		br_dev_delete(dev, NULL);
421 
422 	rtnl_unlock();
423 	return ret;
424 }
425 
426 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
br_min_mtu(const struct net_bridge * br)427 int br_min_mtu(const struct net_bridge *br)
428 {
429 	const struct net_bridge_port *p;
430 	int mtu = 0;
431 
432 	ASSERT_RTNL();
433 
434 	if (list_empty(&br->port_list))
435 		mtu = ETH_DATA_LEN;
436 	else {
437 		list_for_each_entry(p, &br->port_list, list) {
438 			if (!mtu  || p->dev->mtu < mtu)
439 				mtu = p->dev->mtu;
440 		}
441 	}
442 	return mtu;
443 }
444 
br_set_gso_limits(struct net_bridge * br)445 static void br_set_gso_limits(struct net_bridge *br)
446 {
447 	unsigned int gso_max_size = GSO_MAX_SIZE;
448 	u16 gso_max_segs = GSO_MAX_SEGS;
449 	const struct net_bridge_port *p;
450 
451 	list_for_each_entry(p, &br->port_list, list) {
452 		gso_max_size = min(gso_max_size, p->dev->gso_max_size);
453 		gso_max_segs = min(gso_max_segs, p->dev->gso_max_segs);
454 	}
455 	br->dev->gso_max_size = gso_max_size;
456 	br->dev->gso_max_segs = gso_max_segs;
457 }
458 
459 /*
460  * Recomputes features using slave's features
461  */
br_features_recompute(struct net_bridge * br,netdev_features_t features)462 netdev_features_t br_features_recompute(struct net_bridge *br,
463 	netdev_features_t features)
464 {
465 	struct net_bridge_port *p;
466 	netdev_features_t mask;
467 
468 	if (list_empty(&br->port_list))
469 		return features;
470 
471 	mask = features;
472 	features &= ~NETIF_F_ONE_FOR_ALL;
473 
474 	list_for_each_entry(p, &br->port_list, list) {
475 		features = netdev_increment_features(features,
476 						     p->dev->features, mask);
477 	}
478 	features = netdev_add_tso_features(features, mask);
479 
480 	return features;
481 }
482 
483 /* called with RTNL */
br_add_if(struct net_bridge * br,struct net_device * dev)484 int br_add_if(struct net_bridge *br, struct net_device *dev)
485 {
486 	struct net_bridge_port *p;
487 	int err = 0;
488 	unsigned br_hr, dev_hr;
489 	bool changed_addr;
490 
491 	/* Don't allow bridging non-ethernet like devices, or DSA-enabled
492 	 * master network devices since the bridge layer rx_handler prevents
493 	 * the DSA fake ethertype handler to be invoked, so we do not strip off
494 	 * the DSA switch tag protocol header and the bridge layer just return
495 	 * RX_HANDLER_CONSUMED, stopping RX processing for these frames.
496 	 */
497 	if ((dev->flags & IFF_LOOPBACK) ||
498 	    dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
499 	    !is_valid_ether_addr(dev->dev_addr) ||
500 	    netdev_uses_dsa(dev))
501 		return -EINVAL;
502 
503 	/* No bridging of bridges */
504 	if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
505 		return -ELOOP;
506 
507 	/* Device is already being bridged */
508 	if (br_port_exists(dev))
509 		return -EBUSY;
510 
511 	/* No bridging devices that dislike that (e.g. wireless) */
512 	if (dev->priv_flags & IFF_DONT_BRIDGE)
513 		return -EOPNOTSUPP;
514 
515 	p = new_nbp(br, dev);
516 	if (IS_ERR(p))
517 		return PTR_ERR(p);
518 
519 	call_netdevice_notifiers(NETDEV_JOIN, dev);
520 
521 	err = dev_set_allmulti(dev, 1);
522 	if (err)
523 		goto put_back;
524 
525 	err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
526 				   SYSFS_BRIDGE_PORT_ATTR);
527 	if (err)
528 		goto err1;
529 
530 	err = br_sysfs_addif(p);
531 	if (err)
532 		goto err2;
533 
534 	err = br_netpoll_enable(p);
535 	if (err)
536 		goto err3;
537 
538 	err = netdev_rx_handler_register(dev, br_handle_frame, p);
539 	if (err)
540 		goto err4;
541 
542 	dev->priv_flags |= IFF_BRIDGE_PORT;
543 
544 	err = netdev_master_upper_dev_link(dev, br->dev, NULL, NULL);
545 	if (err)
546 		goto err5;
547 
548 	err = nbp_switchdev_mark_set(p);
549 	if (err)
550 		goto err6;
551 
552 	dev_disable_lro(dev);
553 
554 	list_add_rcu(&p->list, &br->port_list);
555 
556 	nbp_update_port_count(br);
557 
558 	netdev_update_features(br->dev);
559 
560 	br_hr = br->dev->needed_headroom;
561 	dev_hr = netdev_get_fwd_headroom(dev);
562 	if (br_hr < dev_hr)
563 		update_headroom(br, dev_hr);
564 	else
565 		netdev_set_rx_headroom(dev, br_hr);
566 
567 	if (br_fdb_insert(br, p, dev->dev_addr, 0))
568 		netdev_err(dev, "failed insert local address bridge forwarding table\n");
569 
570 	err = nbp_vlan_init(p);
571 	if (err) {
572 		netdev_err(dev, "failed to initialize vlan filtering on this port\n");
573 		goto err7;
574 	}
575 
576 	spin_lock_bh(&br->lock);
577 	changed_addr = br_stp_recalculate_bridge_id(br);
578 
579 	if (netif_running(dev) && netif_oper_up(dev) &&
580 	    (br->dev->flags & IFF_UP))
581 		br_stp_enable_port(p);
582 	spin_unlock_bh(&br->lock);
583 
584 	br_ifinfo_notify(RTM_NEWLINK, p);
585 
586 	if (changed_addr)
587 		call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
588 
589 	dev_set_mtu(br->dev, br_min_mtu(br));
590 	br_set_gso_limits(br);
591 
592 	kobject_uevent(&p->kobj, KOBJ_ADD);
593 
594 	return 0;
595 
596 err7:
597 	list_del_rcu(&p->list);
598 	br_fdb_delete_by_port(br, p, 0, 1);
599 	nbp_update_port_count(br);
600 err6:
601 	netdev_upper_dev_unlink(dev, br->dev);
602 err5:
603 	dev->priv_flags &= ~IFF_BRIDGE_PORT;
604 	netdev_rx_handler_unregister(dev);
605 err4:
606 	br_netpoll_disable(p);
607 err3:
608 	sysfs_remove_link(br->ifobj, p->dev->name);
609 err2:
610 	kobject_put(&p->kobj);
611 	p = NULL; /* kobject_put frees */
612 err1:
613 	dev_set_allmulti(dev, -1);
614 put_back:
615 	dev_put(dev);
616 	kfree(p);
617 	return err;
618 }
619 
620 /* called with RTNL */
br_del_if(struct net_bridge * br,struct net_device * dev)621 int br_del_if(struct net_bridge *br, struct net_device *dev)
622 {
623 	struct net_bridge_port *p;
624 	bool changed_addr;
625 
626 	p = br_port_get_rtnl(dev);
627 	if (!p || p->br != br)
628 		return -EINVAL;
629 
630 	/* Since more than one interface can be attached to a bridge,
631 	 * there still maybe an alternate path for netconsole to use;
632 	 * therefore there is no reason for a NETDEV_RELEASE event.
633 	 */
634 	del_nbp(p);
635 
636 	dev_set_mtu(br->dev, br_min_mtu(br));
637 	br_set_gso_limits(br);
638 
639 	spin_lock_bh(&br->lock);
640 	changed_addr = br_stp_recalculate_bridge_id(br);
641 	spin_unlock_bh(&br->lock);
642 
643 	if (changed_addr)
644 		call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
645 
646 	netdev_update_features(br->dev);
647 
648 	return 0;
649 }
650 
br_port_flags_change(struct net_bridge_port * p,unsigned long mask)651 void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
652 {
653 	struct net_bridge *br = p->br;
654 
655 	if (mask & BR_AUTO_MASK)
656 		nbp_update_port_count(br);
657 }
658