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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 
 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, 1);
253         nbp_update_port_count(br);
254 
255         dev->priv_flags &= ~IFF_BRIDGE_PORT;
256 
257         netdev_rx_handler_unregister(dev);
258 
259         netdev_upper_dev_unlink(dev, br->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, 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         p->state = 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,
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 
428         return features;
429 }
430 
431 /* called with RTNL */
432 int br_add_if(struct net_bridge *br, struct net_device *dev)
433 {
434         struct net_bridge_port *p;
435         int err = 0;
436         bool changed_addr;
437 
438         /* Don't allow bridging non-ethernet like devices */
439         if ((dev->flags & IFF_LOOPBACK) ||
440             dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
441             !is_valid_ether_addr(dev->dev_addr))
442                 return -EINVAL;
443 
444         /* No bridging of bridges */
445         if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
446                 return -ELOOP;
447 
448         /* Device is already being bridged */
449         if (br_port_exists(dev))
450                 return -EBUSY;
451 
452         /* No bridging devices that dislike that (e.g. wireless) */
453         if (dev->priv_flags & IFF_DONT_BRIDGE)
454                 return -EOPNOTSUPP;
455 
456         p = new_nbp(br, dev);
457         if (IS_ERR(p))
458                 return PTR_ERR(p);
459 
460         call_netdevice_notifiers(NETDEV_JOIN, dev);
461 
462         err = dev_set_allmulti(dev, 1);
463         if (err)
464                 goto put_back;
465 
466         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
467                                    SYSFS_BRIDGE_PORT_ATTR);
468         if (err)
469                 goto err1;
470 
471         err = br_sysfs_addif(p);
472         if (err)
473                 goto err2;
474 
475         err = br_netpoll_enable(p);
476         if (err)
477                 goto err3;
478 
479         err = netdev_master_upper_dev_link(dev, br->dev);
480         if (err)
481                 goto err4;
482 
483         err = netdev_rx_handler_register(dev, br_handle_frame, p);
484         if (err)
485                 goto err5;
486 
487         dev->priv_flags |= IFF_BRIDGE_PORT;
488 
489         dev_disable_lro(dev);
490 
491         list_add_rcu(&p->list, &br->port_list);
492 
493         nbp_update_port_count(br);
494 
495         netdev_update_features(br->dev);
496 
497         if (br->dev->needed_headroom < dev->needed_headroom)
498                 br->dev->needed_headroom = dev->needed_headroom;
499 
500         if (br_fdb_insert(br, p, dev->dev_addr, 0))
501                 netdev_err(dev, "failed insert local address bridge forwarding table\n");
502 
503         spin_lock_bh(&br->lock);
504         changed_addr = br_stp_recalculate_bridge_id(br);
505 
506         if (netif_running(dev) && netif_oper_up(dev) &&
507             (br->dev->flags & IFF_UP))
508                 br_stp_enable_port(p);
509         spin_unlock_bh(&br->lock);
510 
511         br_ifinfo_notify(RTM_NEWLINK, p);
512 
513         if (changed_addr)
514                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
515 
516         dev_set_mtu(br->dev, br_min_mtu(br));
517 
518         kobject_uevent(&p->kobj, KOBJ_ADD);
519 
520         return 0;
521 
522 err5:
523         netdev_upper_dev_unlink(dev, br->dev);
524 err4:
525         br_netpoll_disable(p);
526 err3:
527         sysfs_remove_link(br->ifobj, p->dev->name);
528 err2:
529         kobject_put(&p->kobj);
530         p = NULL; /* kobject_put frees */
531 err1:
532         dev_set_allmulti(dev, -1);
533 put_back:
534         dev_put(dev);
535         kfree(p);
536         return err;
537 }
538 
539 /* called with RTNL */
540 int br_del_if(struct net_bridge *br, struct net_device *dev)
541 {
542         struct net_bridge_port *p;
543         bool changed_addr;
544 
545         p = br_port_get_rtnl(dev);
546         if (!p || p->br != br)
547                 return -EINVAL;
548 
549         /* Since more than one interface can be attached to a bridge,
550          * there still maybe an alternate path for netconsole to use;
551          * therefore there is no reason for a NETDEV_RELEASE event.
552          */
553         del_nbp(p);
554 
555         spin_lock_bh(&br->lock);
556         changed_addr = br_stp_recalculate_bridge_id(br);
557         spin_unlock_bh(&br->lock);
558 
559         if (changed_addr)
560                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
561 
562         netdev_update_features(br->dev);
563 
564         return 0;
565 }
566 
567 void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
568 {
569         struct net_bridge *br = p->br;
570 
571         if (mask & BR_AUTO_MASK)
572                 nbp_update_port_count(br);
573 }
574 

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