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Linux/net/bridge/br_if.c

  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  */
 37 static int port_cost(struct net_device *dev)
 38 {
 39         struct ethtool_cmd ecmd;
 40 
 41         if (!__ethtool_get_settings(dev, &ecmd)) {
 42                 switch (ethtool_cmd_speed(&ecmd)) {
 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. */
 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 
 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 
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  */
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 
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 
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 
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 
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 
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 
226 /* Delete port(interface) from bridge is done in two steps.
227  * via RCU. First step, marks device as down. That deletes
228  * all the timers and stops new packets from flowing through.
229  *
230  * Final cleanup doesn't occur until after all CPU's finished
231  * processing packets.
232  *
233  * Protected from multiple admin operations by RTNL mutex
234  */
235 static void del_nbp(struct net_bridge_port *p)
236 {
237         struct net_bridge *br = p->br;
238         struct net_device *dev = p->dev;
239 
240         sysfs_remove_link(br->ifobj, p->dev->name);
241 
242         nbp_delete_promisc(p);
243 
244         spin_lock_bh(&br->lock);
245         br_stp_disable_port(p);
246         spin_unlock_bh(&br->lock);
247 
248         br_ifinfo_notify(RTM_DELLINK, p);
249 
250         list_del_rcu(&p->list);
251 
252         nbp_vlan_flush(p);
253         br_fdb_delete_by_port(br, p, 0, 1);
254         switchdev_deferred_process();
255 
256         nbp_update_port_count(br);
257 
258         netdev_upper_dev_unlink(dev, br->dev);
259 
260         dev->priv_flags &= ~IFF_BRIDGE_PORT;
261 
262         netdev_rx_handler_unregister(dev);
263 
264         br_multicast_del_port(p);
265 
266         kobject_uevent(&p->kobj, KOBJ_REMOVE);
267         kobject_del(&p->kobj);
268 
269         br_netpoll_disable(p);
270 
271         call_rcu(&p->rcu, destroy_nbp_rcu);
272 }
273 
274 /* Delete bridge device */
275 void br_dev_delete(struct net_device *dev, struct list_head *head)
276 {
277         struct net_bridge *br = netdev_priv(dev);
278         struct net_bridge_port *p, *n;
279 
280         list_for_each_entry_safe(p, n, &br->port_list, list) {
281                 del_nbp(p);
282         }
283 
284         br_fdb_delete_by_port(br, NULL, 0, 1);
285 
286         br_vlan_flush(br);
287         br_multicast_dev_del(br);
288         del_timer_sync(&br->gc_timer);
289 
290         br_sysfs_delbr(br->dev);
291         unregister_netdevice_queue(br->dev, head);
292 }
293 
294 /* find an available port number */
295 static int find_portno(struct net_bridge *br)
296 {
297         int index;
298         struct net_bridge_port *p;
299         unsigned long *inuse;
300 
301         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
302                         GFP_KERNEL);
303         if (!inuse)
304                 return -ENOMEM;
305 
306         set_bit(0, inuse);      /* zero is reserved */
307         list_for_each_entry(p, &br->port_list, list) {
308                 set_bit(p->port_no, inuse);
309         }
310         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
311         kfree(inuse);
312 
313         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
314 }
315 
316 /* called with RTNL but without bridge lock */
317 static struct net_bridge_port *new_nbp(struct net_bridge *br,
318                                        struct net_device *dev)
319 {
320         int index;
321         struct net_bridge_port *p;
322 
323         index = find_portno(br);
324         if (index < 0)
325                 return ERR_PTR(index);
326 
327         p = kzalloc(sizeof(*p), GFP_KERNEL);
328         if (p == NULL)
329                 return ERR_PTR(-ENOMEM);
330 
331         p->br = br;
332         dev_hold(dev);
333         p->dev = dev;
334         p->path_cost = port_cost(dev);
335         p->priority = 0x8000 >> BR_PORT_BITS;
336         p->port_no = index;
337         p->flags = BR_LEARNING | BR_FLOOD;
338         br_init_port(p);
339         br_set_state(p, BR_STATE_DISABLED);
340         br_stp_port_timer_init(p);
341         br_multicast_add_port(p);
342 
343         return p;
344 }
345 
346 int br_add_bridge(struct net *net, const char *name)
347 {
348         struct net_device *dev;
349         int res;
350 
351         dev = alloc_netdev(sizeof(struct net_bridge), name, NET_NAME_UNKNOWN,
352                            br_dev_setup);
353 
354         if (!dev)
355                 return -ENOMEM;
356 
357         dev_net_set(dev, net);
358         dev->rtnl_link_ops = &br_link_ops;
359 
360         res = register_netdev(dev);
361         if (res)
362                 free_netdev(dev);
363         return res;
364 }
365 
366 int br_del_bridge(struct net *net, const char *name)
367 {
368         struct net_device *dev;
369         int ret = 0;
370 
371         rtnl_lock();
372         dev = __dev_get_by_name(net, name);
373         if (dev == NULL)
374                 ret =  -ENXIO;  /* Could not find device */
375 
376         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
377                 /* Attempt to delete non bridge device! */
378                 ret = -EPERM;
379         }
380 
381         else if (dev->flags & IFF_UP) {
382                 /* Not shutdown yet. */
383                 ret = -EBUSY;
384         }
385 
386         else
387                 br_dev_delete(dev, NULL);
388 
389         rtnl_unlock();
390         return ret;
391 }
392 
393 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
394 int br_min_mtu(const struct net_bridge *br)
395 {
396         const struct net_bridge_port *p;
397         int mtu = 0;
398 
399         ASSERT_RTNL();
400 
401         if (list_empty(&br->port_list))
402                 mtu = ETH_DATA_LEN;
403         else {
404                 list_for_each_entry(p, &br->port_list, list) {
405                         if (!mtu  || p->dev->mtu < mtu)
406                                 mtu = p->dev->mtu;
407                 }
408         }
409         return mtu;
410 }
411 
412 /*
413  * Recomputes features using slave's features
414  */
415 netdev_features_t br_features_recompute(struct net_bridge *br,
416         netdev_features_t features)
417 {
418         struct net_bridge_port *p;
419         netdev_features_t mask;
420 
421         if (list_empty(&br->port_list))
422                 return features;
423 
424         mask = features;
425         features &= ~NETIF_F_ONE_FOR_ALL;
426 
427         list_for_each_entry(p, &br->port_list, list) {
428                 features = netdev_increment_features(features,
429                                                      p->dev->features, mask);
430         }
431         features = netdev_add_tso_features(features, mask);
432 
433         return features;
434 }
435 
436 /* called with RTNL */
437 int br_add_if(struct net_bridge *br, struct net_device *dev)
438 {
439         struct net_bridge_port *p;
440         int err = 0;
441         bool changed_addr;
442 
443         /* Don't allow bridging non-ethernet like devices, or DSA-enabled
444          * master network devices since the bridge layer rx_handler prevents
445          * the DSA fake ethertype handler to be invoked, so we do not strip off
446          * the DSA switch tag protocol header and the bridge layer just return
447          * RX_HANDLER_CONSUMED, stopping RX processing for these frames.
448          */
449         if ((dev->flags & IFF_LOOPBACK) ||
450             dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
451             !is_valid_ether_addr(dev->dev_addr) ||
452             netdev_uses_dsa(dev))
453                 return -EINVAL;
454 
455         /* No bridging of bridges */
456         if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
457                 return -ELOOP;
458 
459         /* Device is already being bridged */
460         if (br_port_exists(dev))
461                 return -EBUSY;
462 
463         /* No bridging devices that dislike that (e.g. wireless) */
464         if (dev->priv_flags & IFF_DONT_BRIDGE)
465                 return -EOPNOTSUPP;
466 
467         p = new_nbp(br, dev);
468         if (IS_ERR(p))
469                 return PTR_ERR(p);
470 
471         call_netdevice_notifiers(NETDEV_JOIN, dev);
472 
473         err = dev_set_allmulti(dev, 1);
474         if (err)
475                 goto put_back;
476 
477         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
478                                    SYSFS_BRIDGE_PORT_ATTR);
479         if (err)
480                 goto err1;
481 
482         err = br_sysfs_addif(p);
483         if (err)
484                 goto err2;
485 
486         err = br_netpoll_enable(p);
487         if (err)
488                 goto err3;
489 
490         err = netdev_rx_handler_register(dev, br_handle_frame, p);
491         if (err)
492                 goto err4;
493 
494         dev->priv_flags |= IFF_BRIDGE_PORT;
495 
496         err = netdev_master_upper_dev_link(dev, br->dev, NULL, NULL);
497         if (err)
498                 goto err5;
499 
500         dev_disable_lro(dev);
501 
502         list_add_rcu(&p->list, &br->port_list);
503 
504         nbp_update_port_count(br);
505 
506         netdev_update_features(br->dev);
507 
508         if (br->dev->needed_headroom < dev->needed_headroom)
509                 br->dev->needed_headroom = dev->needed_headroom;
510 
511         if (br_fdb_insert(br, p, dev->dev_addr, 0))
512                 netdev_err(dev, "failed insert local address bridge forwarding table\n");
513 
514         err = nbp_vlan_init(p);
515         if (err) {
516                 netdev_err(dev, "failed to initialize vlan filtering on this port\n");
517                 goto err6;
518         }
519 
520         spin_lock_bh(&br->lock);
521         changed_addr = br_stp_recalculate_bridge_id(br);
522 
523         if (netif_running(dev) && netif_oper_up(dev) &&
524             (br->dev->flags & IFF_UP))
525                 br_stp_enable_port(p);
526         spin_unlock_bh(&br->lock);
527 
528         br_ifinfo_notify(RTM_NEWLINK, p);
529 
530         if (changed_addr)
531                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
532 
533         dev_set_mtu(br->dev, br_min_mtu(br));
534 
535         kobject_uevent(&p->kobj, KOBJ_ADD);
536 
537         return 0;
538 
539 err6:
540         list_del_rcu(&p->list);
541         br_fdb_delete_by_port(br, p, 0, 1);
542         nbp_update_port_count(br);
543         netdev_upper_dev_unlink(dev, br->dev);
544 
545 err5:
546         dev->priv_flags &= ~IFF_BRIDGE_PORT;
547         netdev_rx_handler_unregister(dev);
548 err4:
549         br_netpoll_disable(p);
550 err3:
551         sysfs_remove_link(br->ifobj, p->dev->name);
552 err2:
553         kobject_put(&p->kobj);
554         p = NULL; /* kobject_put frees */
555 err1:
556         dev_set_allmulti(dev, -1);
557 put_back:
558         dev_put(dev);
559         kfree(p);
560         return err;
561 }
562 
563 /* called with RTNL */
564 int br_del_if(struct net_bridge *br, struct net_device *dev)
565 {
566         struct net_bridge_port *p;
567         bool changed_addr;
568 
569         p = br_port_get_rtnl(dev);
570         if (!p || p->br != br)
571                 return -EINVAL;
572 
573         /* Since more than one interface can be attached to a bridge,
574          * there still maybe an alternate path for netconsole to use;
575          * therefore there is no reason for a NETDEV_RELEASE event.
576          */
577         del_nbp(p);
578 
579         dev_set_mtu(br->dev, br_min_mtu(br));
580 
581         spin_lock_bh(&br->lock);
582         changed_addr = br_stp_recalculate_bridge_id(br);
583         spin_unlock_bh(&br->lock);
584 
585         if (changed_addr)
586                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
587 
588         netdev_update_features(br->dev);
589 
590         return 0;
591 }
592 
593 void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
594 {
595         struct net_bridge *br = p->br;
596 
597         if (mask & BR_AUTO_MASK)
598                 nbp_update_port_count(br);
599 }
600 

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