1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	Generic parts
4  *	Linux ethernet bridge
5  *
6  *	Authors:
7  *	Lennert Buytenhek		<buytenh@gnu.org>
8  */
9 
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/netdevice.h>
13 #include <linux/etherdevice.h>
14 #include <linux/init.h>
15 #include <linux/llc.h>
16 #include <net/llc.h>
17 #include <net/stp.h>
18 #include <net/switchdev.h>
19 
20 #include "br_private.h"
21 
22 /*
23  * Handle changes in state of network devices enslaved to a bridge.
24  *
25  * Note: don't care about up/down if bridge itself is down, because
26  *     port state is checked when bridge is brought up.
27  */
br_device_event(struct notifier_block * unused,unsigned long event,void * ptr)28 static int br_device_event(struct notifier_block *unused, unsigned long event, void *ptr)
29 {
30 	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
31 	struct netdev_notifier_pre_changeaddr_info *prechaddr_info;
32 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
33 	struct net_bridge_port *p;
34 	struct net_bridge *br;
35 	bool notified = false;
36 	bool changed_addr;
37 	int err;
38 
39 	if (netif_is_bridge_master(dev)) {
40 		err = br_vlan_bridge_event(dev, event, ptr);
41 		if (err)
42 			return notifier_from_errno(err);
43 
44 		if (event == NETDEV_REGISTER) {
45 			/* register of bridge completed, add sysfs entries */
46 			err = br_sysfs_addbr(dev);
47 			if (err)
48 				return notifier_from_errno(err);
49 
50 			return NOTIFY_DONE;
51 		}
52 	}
53 
54 	/* not a port of a bridge */
55 	p = br_port_get_rtnl(dev);
56 	if (!p)
57 		return NOTIFY_DONE;
58 
59 	br = p->br;
60 
61 	switch (event) {
62 	case NETDEV_CHANGEMTU:
63 		br_mtu_auto_adjust(br);
64 		break;
65 
66 	case NETDEV_PRE_CHANGEADDR:
67 		if (br->dev->addr_assign_type == NET_ADDR_SET)
68 			break;
69 		prechaddr_info = ptr;
70 		err = dev_pre_changeaddr_notify(br->dev,
71 						prechaddr_info->dev_addr,
72 						extack);
73 		if (err)
74 			return notifier_from_errno(err);
75 		break;
76 
77 	case NETDEV_CHANGEADDR:
78 		spin_lock_bh(&br->lock);
79 		br_fdb_changeaddr(p, dev->dev_addr);
80 		changed_addr = br_stp_recalculate_bridge_id(br);
81 		spin_unlock_bh(&br->lock);
82 
83 		if (changed_addr)
84 			call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
85 
86 		break;
87 
88 	case NETDEV_CHANGE:
89 		br_port_carrier_check(p, &notified);
90 		break;
91 
92 	case NETDEV_FEAT_CHANGE:
93 		netdev_update_features(br->dev);
94 		break;
95 
96 	case NETDEV_DOWN:
97 		spin_lock_bh(&br->lock);
98 		if (br->dev->flags & IFF_UP) {
99 			br_stp_disable_port(p);
100 			notified = true;
101 		}
102 		spin_unlock_bh(&br->lock);
103 		break;
104 
105 	case NETDEV_UP:
106 		if (netif_running(br->dev) && netif_oper_up(dev)) {
107 			spin_lock_bh(&br->lock);
108 			br_stp_enable_port(p);
109 			notified = true;
110 			spin_unlock_bh(&br->lock);
111 		}
112 		break;
113 
114 	case NETDEV_UNREGISTER:
115 		br_del_if(br, dev);
116 		break;
117 
118 	case NETDEV_CHANGENAME:
119 		err = br_sysfs_renameif(p);
120 		if (err)
121 			return notifier_from_errno(err);
122 		break;
123 
124 	case NETDEV_PRE_TYPE_CHANGE:
125 		/* Forbid underlying device to change its type. */
126 		return NOTIFY_BAD;
127 
128 	case NETDEV_RESEND_IGMP:
129 		/* Propagate to master device */
130 		call_netdevice_notifiers(event, br->dev);
131 		break;
132 	}
133 
134 	if (event != NETDEV_UNREGISTER)
135 		br_vlan_port_event(p, event);
136 
137 	/* Events that may cause spanning tree to refresh */
138 	if (!notified && (event == NETDEV_CHANGEADDR || event == NETDEV_UP ||
139 			  event == NETDEV_CHANGE || event == NETDEV_DOWN))
140 		br_ifinfo_notify(RTM_NEWLINK, NULL, p);
141 
142 	return NOTIFY_DONE;
143 }
144 
145 static struct notifier_block br_device_notifier = {
146 	.notifier_call = br_device_event
147 };
148 
149 /* called with RTNL or RCU */
br_switchdev_event(struct notifier_block * unused,unsigned long event,void * ptr)150 static int br_switchdev_event(struct notifier_block *unused,
151 			      unsigned long event, void *ptr)
152 {
153 	struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
154 	struct net_bridge_port *p;
155 	struct net_bridge *br;
156 	struct switchdev_notifier_fdb_info *fdb_info;
157 	int err = NOTIFY_DONE;
158 
159 	p = br_port_get_rtnl_rcu(dev);
160 	if (!p)
161 		goto out;
162 
163 	br = p->br;
164 
165 	switch (event) {
166 	case SWITCHDEV_FDB_ADD_TO_BRIDGE:
167 		fdb_info = ptr;
168 		err = br_fdb_external_learn_add(br, p, fdb_info->addr,
169 						fdb_info->vid, false);
170 		if (err) {
171 			err = notifier_from_errno(err);
172 			break;
173 		}
174 		br_fdb_offloaded_set(br, p, fdb_info->addr,
175 				     fdb_info->vid, true);
176 		break;
177 	case SWITCHDEV_FDB_DEL_TO_BRIDGE:
178 		fdb_info = ptr;
179 		err = br_fdb_external_learn_del(br, p, fdb_info->addr,
180 						fdb_info->vid, false);
181 		if (err)
182 			err = notifier_from_errno(err);
183 		break;
184 	case SWITCHDEV_FDB_OFFLOADED:
185 		fdb_info = ptr;
186 		br_fdb_offloaded_set(br, p, fdb_info->addr,
187 				     fdb_info->vid, fdb_info->offloaded);
188 		break;
189 	case SWITCHDEV_FDB_FLUSH_TO_BRIDGE:
190 		fdb_info = ptr;
191 		/* Don't delete static entries */
192 		br_fdb_delete_by_port(br, p, fdb_info->vid, 0);
193 		break;
194 	}
195 
196 out:
197 	return err;
198 }
199 
200 static struct notifier_block br_switchdev_notifier = {
201 	.notifier_call = br_switchdev_event,
202 };
203 
204 /* called under rtnl_mutex */
br_switchdev_blocking_event(struct notifier_block * nb,unsigned long event,void * ptr)205 static int br_switchdev_blocking_event(struct notifier_block *nb,
206 				       unsigned long event, void *ptr)
207 {
208 	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
209 	struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
210 	struct switchdev_notifier_brport_info *brport_info;
211 	const struct switchdev_brport *b;
212 	struct net_bridge_port *p;
213 	int err = NOTIFY_DONE;
214 
215 	p = br_port_get_rtnl(dev);
216 	if (!p)
217 		goto out;
218 
219 	switch (event) {
220 	case SWITCHDEV_BRPORT_OFFLOADED:
221 		brport_info = ptr;
222 		b = &brport_info->brport;
223 
224 		err = br_switchdev_port_offload(p, b->dev, b->ctx,
225 						b->atomic_nb, b->blocking_nb,
226 						b->tx_fwd_offload, extack);
227 		err = notifier_from_errno(err);
228 		break;
229 	case SWITCHDEV_BRPORT_UNOFFLOADED:
230 		brport_info = ptr;
231 		b = &brport_info->brport;
232 
233 		br_switchdev_port_unoffload(p, b->ctx, b->atomic_nb,
234 					    b->blocking_nb);
235 		break;
236 	}
237 
238 out:
239 	return err;
240 }
241 
242 static struct notifier_block br_switchdev_blocking_notifier = {
243 	.notifier_call = br_switchdev_blocking_event,
244 };
245 
246 /* br_boolopt_toggle - change user-controlled boolean option
247  *
248  * @br: bridge device
249  * @opt: id of the option to change
250  * @on: new option value
251  * @extack: extack for error messages
252  *
253  * Changes the value of the respective boolean option to @on taking care of
254  * any internal option value mapping and configuration.
255  */
br_boolopt_toggle(struct net_bridge * br,enum br_boolopt_id opt,bool on,struct netlink_ext_ack * extack)256 int br_boolopt_toggle(struct net_bridge *br, enum br_boolopt_id opt, bool on,
257 		      struct netlink_ext_ack *extack)
258 {
259 	int err = 0;
260 
261 	switch (opt) {
262 	case BR_BOOLOPT_NO_LL_LEARN:
263 		br_opt_toggle(br, BROPT_NO_LL_LEARN, on);
264 		break;
265 	case BR_BOOLOPT_MCAST_VLAN_SNOOPING:
266 		err = br_multicast_toggle_vlan_snooping(br, on, extack);
267 		break;
268 	case BR_BOOLOPT_MST_ENABLE:
269 		err = br_mst_set_enabled(br, on, extack);
270 		break;
271 	default:
272 		/* shouldn't be called with unsupported options */
273 		WARN_ON(1);
274 		break;
275 	}
276 
277 	return err;
278 }
279 
br_boolopt_get(const struct net_bridge * br,enum br_boolopt_id opt)280 int br_boolopt_get(const struct net_bridge *br, enum br_boolopt_id opt)
281 {
282 	switch (opt) {
283 	case BR_BOOLOPT_NO_LL_LEARN:
284 		return br_opt_get(br, BROPT_NO_LL_LEARN);
285 	case BR_BOOLOPT_MCAST_VLAN_SNOOPING:
286 		return br_opt_get(br, BROPT_MCAST_VLAN_SNOOPING_ENABLED);
287 	case BR_BOOLOPT_MST_ENABLE:
288 		return br_opt_get(br, BROPT_MST_ENABLED);
289 	default:
290 		/* shouldn't be called with unsupported options */
291 		WARN_ON(1);
292 		break;
293 	}
294 
295 	return 0;
296 }
297 
br_boolopt_multi_toggle(struct net_bridge * br,struct br_boolopt_multi * bm,struct netlink_ext_ack * extack)298 int br_boolopt_multi_toggle(struct net_bridge *br,
299 			    struct br_boolopt_multi *bm,
300 			    struct netlink_ext_ack *extack)
301 {
302 	unsigned long bitmap = bm->optmask;
303 	int err = 0;
304 	int opt_id;
305 
306 	for_each_set_bit(opt_id, &bitmap, BR_BOOLOPT_MAX) {
307 		bool on = !!(bm->optval & BIT(opt_id));
308 
309 		err = br_boolopt_toggle(br, opt_id, on, extack);
310 		if (err) {
311 			br_debug(br, "boolopt multi-toggle error: option: %d current: %d new: %d error: %d\n",
312 				 opt_id, br_boolopt_get(br, opt_id), on, err);
313 			break;
314 		}
315 	}
316 
317 	return err;
318 }
319 
br_boolopt_multi_get(const struct net_bridge * br,struct br_boolopt_multi * bm)320 void br_boolopt_multi_get(const struct net_bridge *br,
321 			  struct br_boolopt_multi *bm)
322 {
323 	u32 optval = 0;
324 	int opt_id;
325 
326 	for (opt_id = 0; opt_id < BR_BOOLOPT_MAX; opt_id++)
327 		optval |= (br_boolopt_get(br, opt_id) << opt_id);
328 
329 	bm->optval = optval;
330 	bm->optmask = GENMASK((BR_BOOLOPT_MAX - 1), 0);
331 }
332 
333 /* private bridge options, controlled by the kernel */
br_opt_toggle(struct net_bridge * br,enum net_bridge_opts opt,bool on)334 void br_opt_toggle(struct net_bridge *br, enum net_bridge_opts opt, bool on)
335 {
336 	bool cur = !!br_opt_get(br, opt);
337 
338 	br_debug(br, "toggle option: %d state: %d -> %d\n",
339 		 opt, cur, on);
340 
341 	if (cur == on)
342 		return;
343 
344 	if (on)
345 		set_bit(opt, &br->options);
346 	else
347 		clear_bit(opt, &br->options);
348 }
349 
br_net_exit_batch(struct list_head * net_list)350 static void __net_exit br_net_exit_batch(struct list_head *net_list)
351 {
352 	struct net_device *dev;
353 	struct net *net;
354 	LIST_HEAD(list);
355 
356 	rtnl_lock();
357 
358 	list_for_each_entry(net, net_list, exit_list)
359 		for_each_netdev(net, dev)
360 			if (netif_is_bridge_master(dev))
361 				br_dev_delete(dev, &list);
362 
363 	unregister_netdevice_many(&list);
364 
365 	rtnl_unlock();
366 }
367 
368 static struct pernet_operations br_net_ops = {
369 	.exit_batch	= br_net_exit_batch,
370 };
371 
372 static const struct stp_proto br_stp_proto = {
373 	.rcv	= br_stp_rcv,
374 };
375 
br_init(void)376 static int __init br_init(void)
377 {
378 	int err;
379 
380 	BUILD_BUG_ON(sizeof(struct br_input_skb_cb) > sizeof_field(struct sk_buff, cb));
381 
382 	err = stp_proto_register(&br_stp_proto);
383 	if (err < 0) {
384 		pr_err("bridge: can't register sap for STP\n");
385 		return err;
386 	}
387 
388 	err = br_fdb_init();
389 	if (err)
390 		goto err_out;
391 
392 	err = register_pernet_subsys(&br_net_ops);
393 	if (err)
394 		goto err_out1;
395 
396 	err = br_nf_core_init();
397 	if (err)
398 		goto err_out2;
399 
400 	err = register_netdevice_notifier(&br_device_notifier);
401 	if (err)
402 		goto err_out3;
403 
404 	err = register_switchdev_notifier(&br_switchdev_notifier);
405 	if (err)
406 		goto err_out4;
407 
408 	err = register_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
409 	if (err)
410 		goto err_out5;
411 
412 	err = br_netlink_init();
413 	if (err)
414 		goto err_out6;
415 
416 	brioctl_set(br_ioctl_stub);
417 
418 #if IS_ENABLED(CONFIG_ATM_LANE)
419 	br_fdb_test_addr_hook = br_fdb_test_addr;
420 #endif
421 
422 #if IS_MODULE(CONFIG_BRIDGE_NETFILTER)
423 	pr_info("bridge: filtering via arp/ip/ip6tables is no longer available "
424 		"by default. Update your scripts to load br_netfilter if you "
425 		"need this.\n");
426 #endif
427 
428 	return 0;
429 
430 err_out6:
431 	unregister_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
432 err_out5:
433 	unregister_switchdev_notifier(&br_switchdev_notifier);
434 err_out4:
435 	unregister_netdevice_notifier(&br_device_notifier);
436 err_out3:
437 	br_nf_core_fini();
438 err_out2:
439 	unregister_pernet_subsys(&br_net_ops);
440 err_out1:
441 	br_fdb_fini();
442 err_out:
443 	stp_proto_unregister(&br_stp_proto);
444 	return err;
445 }
446 
br_deinit(void)447 static void __exit br_deinit(void)
448 {
449 	stp_proto_unregister(&br_stp_proto);
450 	br_netlink_fini();
451 	unregister_switchdev_blocking_notifier(&br_switchdev_blocking_notifier);
452 	unregister_switchdev_notifier(&br_switchdev_notifier);
453 	unregister_netdevice_notifier(&br_device_notifier);
454 	brioctl_set(NULL);
455 	unregister_pernet_subsys(&br_net_ops);
456 
457 	rcu_barrier(); /* Wait for completion of call_rcu()'s */
458 
459 	br_nf_core_fini();
460 #if IS_ENABLED(CONFIG_ATM_LANE)
461 	br_fdb_test_addr_hook = NULL;
462 #endif
463 	br_fdb_fini();
464 }
465 
466 module_init(br_init)
467 module_exit(br_deinit)
468 MODULE_LICENSE("GPL");
469 MODULE_VERSION(BR_VERSION);
470 MODULE_ALIAS_RTNL_LINK("bridge");
471