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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 release_nbp(struct kobject *kobj)
 89 {
 90         struct net_bridge_port *p
 91                 = container_of(kobj, struct net_bridge_port, kobj);
 92         kfree(p);
 93 }
 94 
 95 static struct kobj_type brport_ktype = {
 96 #ifdef CONFIG_SYSFS
 97         .sysfs_ops = &brport_sysfs_ops,
 98 #endif
 99         .release = release_nbp,
100 };
101 
102 static void destroy_nbp(struct net_bridge_port *p)
103 {
104         struct net_device *dev = p->dev;
105 
106         p->br = NULL;
107         p->dev = NULL;
108         dev_put(dev);
109 
110         kobject_put(&p->kobj);
111 }
112 
113 static void destroy_nbp_rcu(struct rcu_head *head)
114 {
115         struct net_bridge_port *p =
116                         container_of(head, struct net_bridge_port, rcu);
117         destroy_nbp(p);
118 }
119 
120 /* Delete port(interface) from bridge is done in two steps.
121  * via RCU. First step, marks device as down. That deletes
122  * all the timers and stops new packets from flowing through.
123  *
124  * Final cleanup doesn't occur until after all CPU's finished
125  * processing packets.
126  *
127  * Protected from multiple admin operations by RTNL mutex
128  */
129 static void del_nbp(struct net_bridge_port *p)
130 {
131         struct net_bridge *br = p->br;
132         struct net_device *dev = p->dev;
133 
134         sysfs_remove_link(br->ifobj, p->dev->name);
135 
136         dev_set_promiscuity(dev, -1);
137 
138         spin_lock_bh(&br->lock);
139         br_stp_disable_port(p);
140         spin_unlock_bh(&br->lock);
141 
142         br_ifinfo_notify(RTM_DELLINK, p);
143 
144         nbp_vlan_flush(p);
145         br_fdb_delete_by_port(br, p, 1);
146 
147         list_del_rcu(&p->list);
148 
149         dev->priv_flags &= ~IFF_BRIDGE_PORT;
150 
151         netdev_rx_handler_unregister(dev);
152 
153         netdev_upper_dev_unlink(dev, br->dev);
154 
155         br_multicast_del_port(p);
156 
157         kobject_uevent(&p->kobj, KOBJ_REMOVE);
158         kobject_del(&p->kobj);
159 
160         br_netpoll_disable(p);
161 
162         call_rcu(&p->rcu, destroy_nbp_rcu);
163 }
164 
165 /* Delete bridge device */
166 void br_dev_delete(struct net_device *dev, struct list_head *head)
167 {
168         struct net_bridge *br = netdev_priv(dev);
169         struct net_bridge_port *p, *n;
170 
171         list_for_each_entry_safe(p, n, &br->port_list, list) {
172                 del_nbp(p);
173         }
174 
175         br_fdb_delete_by_port(br, NULL, 1);
176 
177         br_vlan_flush(br);
178         del_timer_sync(&br->gc_timer);
179 
180         br_sysfs_delbr(br->dev);
181         unregister_netdevice_queue(br->dev, head);
182 }
183 
184 /* find an available port number */
185 static int find_portno(struct net_bridge *br)
186 {
187         int index;
188         struct net_bridge_port *p;
189         unsigned long *inuse;
190 
191         inuse = kcalloc(BITS_TO_LONGS(BR_MAX_PORTS), sizeof(unsigned long),
192                         GFP_KERNEL);
193         if (!inuse)
194                 return -ENOMEM;
195 
196         set_bit(0, inuse);      /* zero is reserved */
197         list_for_each_entry(p, &br->port_list, list) {
198                 set_bit(p->port_no, inuse);
199         }
200         index = find_first_zero_bit(inuse, BR_MAX_PORTS);
201         kfree(inuse);
202 
203         return (index >= BR_MAX_PORTS) ? -EXFULL : index;
204 }
205 
206 /* called with RTNL but without bridge lock */
207 static struct net_bridge_port *new_nbp(struct net_bridge *br,
208                                        struct net_device *dev)
209 {
210         int index;
211         struct net_bridge_port *p;
212 
213         index = find_portno(br);
214         if (index < 0)
215                 return ERR_PTR(index);
216 
217         p = kzalloc(sizeof(*p), GFP_KERNEL);
218         if (p == NULL)
219                 return ERR_PTR(-ENOMEM);
220 
221         p->br = br;
222         dev_hold(dev);
223         p->dev = dev;
224         p->path_cost = port_cost(dev);
225         p->priority = 0x8000 >> BR_PORT_BITS;
226         p->port_no = index;
227         p->flags = BR_LEARNING | BR_FLOOD;
228         br_init_port(p);
229         p->state = BR_STATE_DISABLED;
230         br_stp_port_timer_init(p);
231         br_multicast_add_port(p);
232 
233         return p;
234 }
235 
236 int br_add_bridge(struct net *net, const char *name)
237 {
238         struct net_device *dev;
239         int res;
240 
241         dev = alloc_netdev(sizeof(struct net_bridge), name,
242                            br_dev_setup);
243 
244         if (!dev)
245                 return -ENOMEM;
246 
247         dev_net_set(dev, net);
248         dev->rtnl_link_ops = &br_link_ops;
249 
250         res = register_netdev(dev);
251         if (res)
252                 free_netdev(dev);
253         return res;
254 }
255 
256 int br_del_bridge(struct net *net, const char *name)
257 {
258         struct net_device *dev;
259         int ret = 0;
260 
261         rtnl_lock();
262         dev = __dev_get_by_name(net, name);
263         if (dev == NULL)
264                 ret =  -ENXIO;  /* Could not find device */
265 
266         else if (!(dev->priv_flags & IFF_EBRIDGE)) {
267                 /* Attempt to delete non bridge device! */
268                 ret = -EPERM;
269         }
270 
271         else if (dev->flags & IFF_UP) {
272                 /* Not shutdown yet. */
273                 ret = -EBUSY;
274         }
275 
276         else
277                 br_dev_delete(dev, NULL);
278 
279         rtnl_unlock();
280         return ret;
281 }
282 
283 /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */
284 int br_min_mtu(const struct net_bridge *br)
285 {
286         const struct net_bridge_port *p;
287         int mtu = 0;
288 
289         ASSERT_RTNL();
290 
291         if (list_empty(&br->port_list))
292                 mtu = ETH_DATA_LEN;
293         else {
294                 list_for_each_entry(p, &br->port_list, list) {
295                         if (!mtu  || p->dev->mtu < mtu)
296                                 mtu = p->dev->mtu;
297                 }
298         }
299         return mtu;
300 }
301 
302 /*
303  * Recomputes features using slave's features
304  */
305 netdev_features_t br_features_recompute(struct net_bridge *br,
306         netdev_features_t features)
307 {
308         struct net_bridge_port *p;
309         netdev_features_t mask;
310 
311         if (list_empty(&br->port_list))
312                 return features;
313 
314         mask = features;
315         features &= ~NETIF_F_ONE_FOR_ALL;
316 
317         list_for_each_entry(p, &br->port_list, list) {
318                 features = netdev_increment_features(features,
319                                                      p->dev->features, mask);
320         }
321 
322         return features;
323 }
324 
325 /* called with RTNL */
326 int br_add_if(struct net_bridge *br, struct net_device *dev)
327 {
328         struct net_bridge_port *p;
329         int err = 0;
330         bool changed_addr;
331 
332         /* Don't allow bridging non-ethernet like devices */
333         if ((dev->flags & IFF_LOOPBACK) ||
334             dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
335             !is_valid_ether_addr(dev->dev_addr))
336                 return -EINVAL;
337 
338         /* No bridging of bridges */
339         if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
340                 return -ELOOP;
341 
342         /* Device is already being bridged */
343         if (br_port_exists(dev))
344                 return -EBUSY;
345 
346         /* No bridging devices that dislike that (e.g. wireless) */
347         if (dev->priv_flags & IFF_DONT_BRIDGE)
348                 return -EOPNOTSUPP;
349 
350         p = new_nbp(br, dev);
351         if (IS_ERR(p))
352                 return PTR_ERR(p);
353 
354         call_netdevice_notifiers(NETDEV_JOIN, dev);
355 
356         err = dev_set_promiscuity(dev, 1);
357         if (err)
358                 goto put_back;
359 
360         err = kobject_init_and_add(&p->kobj, &brport_ktype, &(dev->dev.kobj),
361                                    SYSFS_BRIDGE_PORT_ATTR);
362         if (err)
363                 goto err1;
364 
365         err = br_sysfs_addif(p);
366         if (err)
367                 goto err2;
368 
369         err = br_netpoll_enable(p, GFP_KERNEL);
370         if (err)
371                 goto err3;
372 
373         err = netdev_master_upper_dev_link(dev, br->dev);
374         if (err)
375                 goto err4;
376 
377         err = netdev_rx_handler_register(dev, br_handle_frame, p);
378         if (err)
379                 goto err5;
380 
381         dev->priv_flags |= IFF_BRIDGE_PORT;
382 
383         dev_disable_lro(dev);
384 
385         list_add_rcu(&p->list, &br->port_list);
386 
387         netdev_update_features(br->dev);
388 
389         if (br->dev->needed_headroom < dev->needed_headroom)
390                 br->dev->needed_headroom = dev->needed_headroom;
391 
392         if (br_fdb_insert(br, p, dev->dev_addr, 0))
393                 netdev_err(dev, "failed insert local address bridge forwarding table\n");
394 
395         spin_lock_bh(&br->lock);
396         changed_addr = br_stp_recalculate_bridge_id(br);
397 
398         if (netif_running(dev) && netif_oper_up(dev) &&
399             (br->dev->flags & IFF_UP))
400                 br_stp_enable_port(p);
401         spin_unlock_bh(&br->lock);
402 
403         br_ifinfo_notify(RTM_NEWLINK, p);
404 
405         if (changed_addr)
406                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
407 
408         dev_set_mtu(br->dev, br_min_mtu(br));
409 
410         kobject_uevent(&p->kobj, KOBJ_ADD);
411 
412         return 0;
413 
414 err5:
415         netdev_upper_dev_unlink(dev, br->dev);
416 err4:
417         br_netpoll_disable(p);
418 err3:
419         sysfs_remove_link(br->ifobj, p->dev->name);
420 err2:
421         kobject_put(&p->kobj);
422         p = NULL; /* kobject_put frees */
423 err1:
424         dev_set_promiscuity(dev, -1);
425 put_back:
426         dev_put(dev);
427         kfree(p);
428         return err;
429 }
430 
431 /* called with RTNL */
432 int br_del_if(struct net_bridge *br, struct net_device *dev)
433 {
434         struct net_bridge_port *p;
435         bool changed_addr;
436 
437         p = br_port_get_rtnl(dev);
438         if (!p || p->br != br)
439                 return -EINVAL;
440 
441         /* Since more than one interface can be attached to a bridge,
442          * there still maybe an alternate path for netconsole to use;
443          * therefore there is no reason for a NETDEV_RELEASE event.
444          */
445         del_nbp(p);
446 
447         spin_lock_bh(&br->lock);
448         changed_addr = br_stp_recalculate_bridge_id(br);
449         spin_unlock_bh(&br->lock);
450 
451         if (changed_addr)
452                 call_netdevice_notifiers(NETDEV_CHANGEADDR, br->dev);
453 
454         netdev_update_features(br->dev);
455 
456         return 0;
457 }
458 

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