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TOMOYO Linux Cross Reference
Linux/net/batman-adv/hard-interface.c

Version: ~ [ linux-4.18-rc1 ] ~ [ linux-4.17.2 ] ~ [ linux-4.16.16 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.50 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.109 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.138 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.113 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.57 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.27.62 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0
  2 /* Copyright (C) 2007-2018  B.A.T.M.A.N. contributors:
  3  *
  4  * Marek Lindner, Simon Wunderlich
  5  *
  6  * This program is free software; you can redistribute it and/or
  7  * modify it under the terms of version 2 of the GNU General Public
  8  * License as published by the Free Software Foundation.
  9  *
 10  * This program is distributed in the hope that it will be useful, but
 11  * WITHOUT ANY WARRANTY; without even the implied warranty of
 12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 13  * General Public License for more details.
 14  *
 15  * You should have received a copy of the GNU General Public License
 16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
 17  */
 18 
 19 #include "hard-interface.h"
 20 #include "main.h"
 21 
 22 #include <linux/atomic.h>
 23 #include <linux/bug.h>
 24 #include <linux/byteorder/generic.h>
 25 #include <linux/errno.h>
 26 #include <linux/gfp.h>
 27 #include <linux/if.h>
 28 #include <linux/if_arp.h>
 29 #include <linux/if_ether.h>
 30 #include <linux/kernel.h>
 31 #include <linux/kref.h>
 32 #include <linux/list.h>
 33 #include <linux/netdevice.h>
 34 #include <linux/printk.h>
 35 #include <linux/rculist.h>
 36 #include <linux/rtnetlink.h>
 37 #include <linux/slab.h>
 38 #include <linux/spinlock.h>
 39 #include <net/net_namespace.h>
 40 #include <net/rtnetlink.h>
 41 #include <uapi/linux/batadv_packet.h>
 42 
 43 #include "bat_v.h"
 44 #include "bridge_loop_avoidance.h"
 45 #include "debugfs.h"
 46 #include "distributed-arp-table.h"
 47 #include "gateway_client.h"
 48 #include "log.h"
 49 #include "originator.h"
 50 #include "send.h"
 51 #include "soft-interface.h"
 52 #include "sysfs.h"
 53 #include "translation-table.h"
 54 
 55 /**
 56  * batadv_hardif_release() - release hard interface from lists and queue for
 57  *  free after rcu grace period
 58  * @ref: kref pointer of the hard interface
 59  */
 60 void batadv_hardif_release(struct kref *ref)
 61 {
 62         struct batadv_hard_iface *hard_iface;
 63 
 64         hard_iface = container_of(ref, struct batadv_hard_iface, refcount);
 65         dev_put(hard_iface->net_dev);
 66 
 67         kfree_rcu(hard_iface, rcu);
 68 }
 69 
 70 /**
 71  * batadv_hardif_get_by_netdev() - Get hard interface object of a net_device
 72  * @net_dev: net_device to search for
 73  *
 74  * Return: batadv_hard_iface of net_dev (with increased refcnt), NULL on errors
 75  */
 76 struct batadv_hard_iface *
 77 batadv_hardif_get_by_netdev(const struct net_device *net_dev)
 78 {
 79         struct batadv_hard_iface *hard_iface;
 80 
 81         rcu_read_lock();
 82         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 83                 if (hard_iface->net_dev == net_dev &&
 84                     kref_get_unless_zero(&hard_iface->refcount))
 85                         goto out;
 86         }
 87 
 88         hard_iface = NULL;
 89 
 90 out:
 91         rcu_read_unlock();
 92         return hard_iface;
 93 }
 94 
 95 /**
 96  * batadv_getlink_net() - return link net namespace (of use fallback)
 97  * @netdev: net_device to check
 98  * @fallback_net: return in case get_link_net is not available for @netdev
 99  *
100  * Return: result of rtnl_link_ops->get_link_net or @fallback_net
101  */
102 static struct net *batadv_getlink_net(const struct net_device *netdev,
103                                       struct net *fallback_net)
104 {
105         if (!netdev->rtnl_link_ops)
106                 return fallback_net;
107 
108         if (!netdev->rtnl_link_ops->get_link_net)
109                 return fallback_net;
110 
111         return netdev->rtnl_link_ops->get_link_net(netdev);
112 }
113 
114 /**
115  * batadv_mutual_parents() - check if two devices are each others parent
116  * @dev1: 1st net dev
117  * @net1: 1st devices netns
118  * @dev2: 2nd net dev
119  * @net2: 2nd devices netns
120  *
121  * veth devices come in pairs and each is the parent of the other!
122  *
123  * Return: true if the devices are each others parent, otherwise false
124  */
125 static bool batadv_mutual_parents(const struct net_device *dev1,
126                                   struct net *net1,
127                                   const struct net_device *dev2,
128                                   struct net *net2)
129 {
130         int dev1_parent_iflink = dev_get_iflink(dev1);
131         int dev2_parent_iflink = dev_get_iflink(dev2);
132         const struct net *dev1_parent_net;
133         const struct net *dev2_parent_net;
134 
135         dev1_parent_net = batadv_getlink_net(dev1, net1);
136         dev2_parent_net = batadv_getlink_net(dev2, net2);
137 
138         if (!dev1_parent_iflink || !dev2_parent_iflink)
139                 return false;
140 
141         return (dev1_parent_iflink == dev2->ifindex) &&
142                (dev2_parent_iflink == dev1->ifindex) &&
143                net_eq(dev1_parent_net, net2) &&
144                net_eq(dev2_parent_net, net1);
145 }
146 
147 /**
148  * batadv_is_on_batman_iface() - check if a device is a batman iface descendant
149  * @net_dev: the device to check
150  *
151  * If the user creates any virtual device on top of a batman-adv interface, it
152  * is important to prevent this new interface to be used to create a new mesh
153  * network (this behaviour would lead to a batman-over-batman configuration).
154  * This function recursively checks all the fathers of the device passed as
155  * argument looking for a batman-adv soft interface.
156  *
157  * Return: true if the device is descendant of a batman-adv mesh interface (or
158  * if it is a batman-adv interface itself), false otherwise
159  */
160 static bool batadv_is_on_batman_iface(const struct net_device *net_dev)
161 {
162         struct net *net = dev_net(net_dev);
163         struct net_device *parent_dev;
164         struct net *parent_net;
165         bool ret;
166 
167         /* check if this is a batman-adv mesh interface */
168         if (batadv_softif_is_valid(net_dev))
169                 return true;
170 
171         /* no more parents..stop recursion */
172         if (dev_get_iflink(net_dev) == 0 ||
173             dev_get_iflink(net_dev) == net_dev->ifindex)
174                 return false;
175 
176         parent_net = batadv_getlink_net(net_dev, net);
177 
178         /* recurse over the parent device */
179         parent_dev = __dev_get_by_index((struct net *)parent_net,
180                                         dev_get_iflink(net_dev));
181         /* if we got a NULL parent_dev there is something broken.. */
182         if (WARN(!parent_dev, "Cannot find parent device"))
183                 return false;
184 
185         if (batadv_mutual_parents(net_dev, net, parent_dev, parent_net))
186                 return false;
187 
188         ret = batadv_is_on_batman_iface(parent_dev);
189 
190         return ret;
191 }
192 
193 static bool batadv_is_valid_iface(const struct net_device *net_dev)
194 {
195         if (net_dev->flags & IFF_LOOPBACK)
196                 return false;
197 
198         if (net_dev->type != ARPHRD_ETHER)
199                 return false;
200 
201         if (net_dev->addr_len != ETH_ALEN)
202                 return false;
203 
204         /* no batman over batman */
205         if (batadv_is_on_batman_iface(net_dev))
206                 return false;
207 
208         return true;
209 }
210 
211 /**
212  * batadv_get_real_netdevice() - check if the given netdev struct is a virtual
213  *  interface on top of another 'real' interface
214  * @netdev: the device to check
215  *
216  * Callers must hold the rtnl semaphore. You may want batadv_get_real_netdev()
217  * instead of this.
218  *
219  * Return: the 'real' net device or the original net device and NULL in case
220  *  of an error.
221  */
222 static struct net_device *batadv_get_real_netdevice(struct net_device *netdev)
223 {
224         struct batadv_hard_iface *hard_iface = NULL;
225         struct net_device *real_netdev = NULL;
226         struct net *real_net;
227         struct net *net;
228         int ifindex;
229 
230         ASSERT_RTNL();
231 
232         if (!netdev)
233                 return NULL;
234 
235         if (netdev->ifindex == dev_get_iflink(netdev)) {
236                 dev_hold(netdev);
237                 return netdev;
238         }
239 
240         hard_iface = batadv_hardif_get_by_netdev(netdev);
241         if (!hard_iface || !hard_iface->soft_iface)
242                 goto out;
243 
244         net = dev_net(hard_iface->soft_iface);
245         ifindex = dev_get_iflink(netdev);
246         real_net = batadv_getlink_net(netdev, net);
247         real_netdev = dev_get_by_index(real_net, ifindex);
248 
249 out:
250         if (hard_iface)
251                 batadv_hardif_put(hard_iface);
252         return real_netdev;
253 }
254 
255 /**
256  * batadv_get_real_netdev() - check if the given net_device struct is a virtual
257  *  interface on top of another 'real' interface
258  * @net_device: the device to check
259  *
260  * Return: the 'real' net device or the original net device and NULL in case
261  *  of an error.
262  */
263 struct net_device *batadv_get_real_netdev(struct net_device *net_device)
264 {
265         struct net_device *real_netdev;
266 
267         rtnl_lock();
268         real_netdev = batadv_get_real_netdevice(net_device);
269         rtnl_unlock();
270 
271         return real_netdev;
272 }
273 
274 /**
275  * batadv_is_wext_netdev() - check if the given net_device struct is a
276  *  wext wifi interface
277  * @net_device: the device to check
278  *
279  * Return: true if the net device is a wext wireless device, false
280  *  otherwise.
281  */
282 static bool batadv_is_wext_netdev(struct net_device *net_device)
283 {
284         if (!net_device)
285                 return false;
286 
287 #ifdef CONFIG_WIRELESS_EXT
288         /* pre-cfg80211 drivers have to implement WEXT, so it is possible to
289          * check for wireless_handlers != NULL
290          */
291         if (net_device->wireless_handlers)
292                 return true;
293 #endif
294 
295         return false;
296 }
297 
298 /**
299  * batadv_is_cfg80211_netdev() - check if the given net_device struct is a
300  *  cfg80211 wifi interface
301  * @net_device: the device to check
302  *
303  * Return: true if the net device is a cfg80211 wireless device, false
304  *  otherwise.
305  */
306 static bool batadv_is_cfg80211_netdev(struct net_device *net_device)
307 {
308         if (!net_device)
309                 return false;
310 
311         /* cfg80211 drivers have to set ieee80211_ptr */
312         if (net_device->ieee80211_ptr)
313                 return true;
314 
315         return false;
316 }
317 
318 /**
319  * batadv_wifi_flags_evaluate() - calculate wifi flags for net_device
320  * @net_device: the device to check
321  *
322  * Return: batadv_hard_iface_wifi_flags flags of the device
323  */
324 static u32 batadv_wifi_flags_evaluate(struct net_device *net_device)
325 {
326         u32 wifi_flags = 0;
327         struct net_device *real_netdev;
328 
329         if (batadv_is_wext_netdev(net_device))
330                 wifi_flags |= BATADV_HARDIF_WIFI_WEXT_DIRECT;
331 
332         if (batadv_is_cfg80211_netdev(net_device))
333                 wifi_flags |= BATADV_HARDIF_WIFI_CFG80211_DIRECT;
334 
335         real_netdev = batadv_get_real_netdevice(net_device);
336         if (!real_netdev)
337                 return wifi_flags;
338 
339         if (real_netdev == net_device)
340                 goto out;
341 
342         if (batadv_is_wext_netdev(real_netdev))
343                 wifi_flags |= BATADV_HARDIF_WIFI_WEXT_INDIRECT;
344 
345         if (batadv_is_cfg80211_netdev(real_netdev))
346                 wifi_flags |= BATADV_HARDIF_WIFI_CFG80211_INDIRECT;
347 
348 out:
349         dev_put(real_netdev);
350         return wifi_flags;
351 }
352 
353 /**
354  * batadv_is_cfg80211_hardif() - check if the given hardif is a cfg80211 wifi
355  *  interface
356  * @hard_iface: the device to check
357  *
358  * Return: true if the net device is a cfg80211 wireless device, false
359  *  otherwise.
360  */
361 bool batadv_is_cfg80211_hardif(struct batadv_hard_iface *hard_iface)
362 {
363         u32 allowed_flags = 0;
364 
365         allowed_flags |= BATADV_HARDIF_WIFI_CFG80211_DIRECT;
366         allowed_flags |= BATADV_HARDIF_WIFI_CFG80211_INDIRECT;
367 
368         return !!(hard_iface->wifi_flags & allowed_flags);
369 }
370 
371 /**
372  * batadv_is_wifi_hardif() - check if the given hardif is a wifi interface
373  * @hard_iface: the device to check
374  *
375  * Return: true if the net device is a 802.11 wireless device, false otherwise.
376  */
377 bool batadv_is_wifi_hardif(struct batadv_hard_iface *hard_iface)
378 {
379         if (!hard_iface)
380                 return false;
381 
382         return hard_iface->wifi_flags != 0;
383 }
384 
385 /**
386  * batadv_hardif_no_broadcast() - check whether (re)broadcast is necessary
387  * @if_outgoing: the outgoing interface checked and considered for (re)broadcast
388  * @orig_addr: the originator of this packet
389  * @orig_neigh: originator address of the forwarder we just got the packet from
390  *  (NULL if we originated)
391  *
392  * Checks whether a packet needs to be (re)broadcasted on the given interface.
393  *
394  * Return:
395  *      BATADV_HARDIF_BCAST_NORECIPIENT: No neighbor on interface
396  *      BATADV_HARDIF_BCAST_DUPFWD: Just one neighbor, but it is the forwarder
397  *      BATADV_HARDIF_BCAST_DUPORIG: Just one neighbor, but it is the originator
398  *      BATADV_HARDIF_BCAST_OK: Several neighbors, must broadcast
399  */
400 int batadv_hardif_no_broadcast(struct batadv_hard_iface *if_outgoing,
401                                u8 *orig_addr, u8 *orig_neigh)
402 {
403         struct batadv_hardif_neigh_node *hardif_neigh;
404         struct hlist_node *first;
405         int ret = BATADV_HARDIF_BCAST_OK;
406 
407         rcu_read_lock();
408 
409         /* 0 neighbors -> no (re)broadcast */
410         first = rcu_dereference(hlist_first_rcu(&if_outgoing->neigh_list));
411         if (!first) {
412                 ret = BATADV_HARDIF_BCAST_NORECIPIENT;
413                 goto out;
414         }
415 
416         /* >1 neighbors -> (re)brodcast */
417         if (rcu_dereference(hlist_next_rcu(first)))
418                 goto out;
419 
420         hardif_neigh = hlist_entry(first, struct batadv_hardif_neigh_node,
421                                    list);
422 
423         /* 1 neighbor, is the originator -> no rebroadcast */
424         if (orig_addr && batadv_compare_eth(hardif_neigh->orig, orig_addr)) {
425                 ret = BATADV_HARDIF_BCAST_DUPORIG;
426         /* 1 neighbor, is the one we received from -> no rebroadcast */
427         } else if (orig_neigh &&
428                    batadv_compare_eth(hardif_neigh->orig, orig_neigh)) {
429                 ret = BATADV_HARDIF_BCAST_DUPFWD;
430         }
431 
432 out:
433         rcu_read_unlock();
434         return ret;
435 }
436 
437 static struct batadv_hard_iface *
438 batadv_hardif_get_active(const struct net_device *soft_iface)
439 {
440         struct batadv_hard_iface *hard_iface;
441 
442         rcu_read_lock();
443         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
444                 if (hard_iface->soft_iface != soft_iface)
445                         continue;
446 
447                 if (hard_iface->if_status == BATADV_IF_ACTIVE &&
448                     kref_get_unless_zero(&hard_iface->refcount))
449                         goto out;
450         }
451 
452         hard_iface = NULL;
453 
454 out:
455         rcu_read_unlock();
456         return hard_iface;
457 }
458 
459 static void batadv_primary_if_update_addr(struct batadv_priv *bat_priv,
460                                           struct batadv_hard_iface *oldif)
461 {
462         struct batadv_hard_iface *primary_if;
463 
464         primary_if = batadv_primary_if_get_selected(bat_priv);
465         if (!primary_if)
466                 goto out;
467 
468         batadv_dat_init_own_addr(bat_priv, primary_if);
469         batadv_bla_update_orig_address(bat_priv, primary_if, oldif);
470 out:
471         if (primary_if)
472                 batadv_hardif_put(primary_if);
473 }
474 
475 static void batadv_primary_if_select(struct batadv_priv *bat_priv,
476                                      struct batadv_hard_iface *new_hard_iface)
477 {
478         struct batadv_hard_iface *curr_hard_iface;
479 
480         ASSERT_RTNL();
481 
482         if (new_hard_iface)
483                 kref_get(&new_hard_iface->refcount);
484 
485         curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
486         rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);
487 
488         if (!new_hard_iface)
489                 goto out;
490 
491         bat_priv->algo_ops->iface.primary_set(new_hard_iface);
492         batadv_primary_if_update_addr(bat_priv, curr_hard_iface);
493 
494 out:
495         if (curr_hard_iface)
496                 batadv_hardif_put(curr_hard_iface);
497 }
498 
499 static bool
500 batadv_hardif_is_iface_up(const struct batadv_hard_iface *hard_iface)
501 {
502         if (hard_iface->net_dev->flags & IFF_UP)
503                 return true;
504 
505         return false;
506 }
507 
508 static void batadv_check_known_mac_addr(const struct net_device *net_dev)
509 {
510         const struct batadv_hard_iface *hard_iface;
511 
512         rcu_read_lock();
513         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
514                 if (hard_iface->if_status != BATADV_IF_ACTIVE &&
515                     hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED)
516                         continue;
517 
518                 if (hard_iface->net_dev == net_dev)
519                         continue;
520 
521                 if (!batadv_compare_eth(hard_iface->net_dev->dev_addr,
522                                         net_dev->dev_addr))
523                         continue;
524 
525                 pr_warn("The newly added mac address (%pM) already exists on: %s\n",
526                         net_dev->dev_addr, hard_iface->net_dev->name);
527                 pr_warn("It is strongly recommended to keep mac addresses unique to avoid problems!\n");
528         }
529         rcu_read_unlock();
530 }
531 
532 /**
533  * batadv_hardif_recalc_extra_skbroom() - Recalculate skbuff extra head/tailroom
534  * @soft_iface: netdev struct of the mesh interface
535  */
536 static void batadv_hardif_recalc_extra_skbroom(struct net_device *soft_iface)
537 {
538         const struct batadv_hard_iface *hard_iface;
539         unsigned short lower_header_len = ETH_HLEN;
540         unsigned short lower_headroom = 0;
541         unsigned short lower_tailroom = 0;
542         unsigned short needed_headroom;
543 
544         rcu_read_lock();
545         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
546                 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
547                         continue;
548 
549                 if (hard_iface->soft_iface != soft_iface)
550                         continue;
551 
552                 lower_header_len = max_t(unsigned short, lower_header_len,
553                                          hard_iface->net_dev->hard_header_len);
554 
555                 lower_headroom = max_t(unsigned short, lower_headroom,
556                                        hard_iface->net_dev->needed_headroom);
557 
558                 lower_tailroom = max_t(unsigned short, lower_tailroom,
559                                        hard_iface->net_dev->needed_tailroom);
560         }
561         rcu_read_unlock();
562 
563         needed_headroom = lower_headroom + (lower_header_len - ETH_HLEN);
564         needed_headroom += batadv_max_header_len();
565 
566         soft_iface->needed_headroom = needed_headroom;
567         soft_iface->needed_tailroom = lower_tailroom;
568 }
569 
570 /**
571  * batadv_hardif_min_mtu() - Calculate maximum MTU for soft interface
572  * @soft_iface: netdev struct of the soft interface
573  *
574  * Return: MTU for the soft-interface (limited by the minimal MTU of all active
575  *  slave interfaces)
576  */
577 int batadv_hardif_min_mtu(struct net_device *soft_iface)
578 {
579         struct batadv_priv *bat_priv = netdev_priv(soft_iface);
580         const struct batadv_hard_iface *hard_iface;
581         int min_mtu = INT_MAX;
582 
583         rcu_read_lock();
584         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
585                 if (hard_iface->if_status != BATADV_IF_ACTIVE &&
586                     hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED)
587                         continue;
588 
589                 if (hard_iface->soft_iface != soft_iface)
590                         continue;
591 
592                 min_mtu = min_t(int, hard_iface->net_dev->mtu, min_mtu);
593         }
594         rcu_read_unlock();
595 
596         if (atomic_read(&bat_priv->fragmentation) == 0)
597                 goto out;
598 
599         /* with fragmentation enabled the maximum size of internally generated
600          * packets such as translation table exchanges or tvlv containers, etc
601          * has to be calculated
602          */
603         min_mtu = min_t(int, min_mtu, BATADV_FRAG_MAX_FRAG_SIZE);
604         min_mtu -= sizeof(struct batadv_frag_packet);
605         min_mtu *= BATADV_FRAG_MAX_FRAGMENTS;
606 
607 out:
608         /* report to the other components the maximum amount of bytes that
609          * batman-adv can send over the wire (without considering the payload
610          * overhead). For example, this value is used by TT to compute the
611          * maximum local table table size
612          */
613         atomic_set(&bat_priv->packet_size_max, min_mtu);
614 
615         /* the real soft-interface MTU is computed by removing the payload
616          * overhead from the maximum amount of bytes that was just computed.
617          *
618          * However batman-adv does not support MTUs bigger than ETH_DATA_LEN
619          */
620         return min_t(int, min_mtu - batadv_max_header_len(), ETH_DATA_LEN);
621 }
622 
623 /**
624  * batadv_update_min_mtu() - Adjusts the MTU if a new interface with a smaller
625  *  MTU appeared
626  * @soft_iface: netdev struct of the soft interface
627  */
628 void batadv_update_min_mtu(struct net_device *soft_iface)
629 {
630         soft_iface->mtu = batadv_hardif_min_mtu(soft_iface);
631 
632         /* Check if the local translate table should be cleaned up to match a
633          * new (and smaller) MTU.
634          */
635         batadv_tt_local_resize_to_mtu(soft_iface);
636 }
637 
638 static void
639 batadv_hardif_activate_interface(struct batadv_hard_iface *hard_iface)
640 {
641         struct batadv_priv *bat_priv;
642         struct batadv_hard_iface *primary_if = NULL;
643 
644         if (hard_iface->if_status != BATADV_IF_INACTIVE)
645                 goto out;
646 
647         bat_priv = netdev_priv(hard_iface->soft_iface);
648 
649         bat_priv->algo_ops->iface.update_mac(hard_iface);
650         hard_iface->if_status = BATADV_IF_TO_BE_ACTIVATED;
651 
652         /* the first active interface becomes our primary interface or
653          * the next active interface after the old primary interface was removed
654          */
655         primary_if = batadv_primary_if_get_selected(bat_priv);
656         if (!primary_if)
657                 batadv_primary_if_select(bat_priv, hard_iface);
658 
659         batadv_info(hard_iface->soft_iface, "Interface activated: %s\n",
660                     hard_iface->net_dev->name);
661 
662         batadv_update_min_mtu(hard_iface->soft_iface);
663 
664         if (bat_priv->algo_ops->iface.activate)
665                 bat_priv->algo_ops->iface.activate(hard_iface);
666 
667 out:
668         if (primary_if)
669                 batadv_hardif_put(primary_if);
670 }
671 
672 static void
673 batadv_hardif_deactivate_interface(struct batadv_hard_iface *hard_iface)
674 {
675         if (hard_iface->if_status != BATADV_IF_ACTIVE &&
676             hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED)
677                 return;
678 
679         hard_iface->if_status = BATADV_IF_INACTIVE;
680 
681         batadv_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
682                     hard_iface->net_dev->name);
683 
684         batadv_update_min_mtu(hard_iface->soft_iface);
685 }
686 
687 /**
688  * batadv_master_del_slave() - remove hard_iface from the current master iface
689  * @slave: the interface enslaved in another master
690  * @master: the master from which slave has to be removed
691  *
692  * Invoke ndo_del_slave on master passing slave as argument. In this way slave
693  * is free'd and master can correctly change its internal state.
694  *
695  * Return: 0 on success, a negative value representing the error otherwise
696  */
697 static int batadv_master_del_slave(struct batadv_hard_iface *slave,
698                                    struct net_device *master)
699 {
700         int ret;
701 
702         if (!master)
703                 return 0;
704 
705         ret = -EBUSY;
706         if (master->netdev_ops->ndo_del_slave)
707                 ret = master->netdev_ops->ndo_del_slave(master, slave->net_dev);
708 
709         return ret;
710 }
711 
712 /**
713  * batadv_hardif_enable_interface() - Enslave hard interface to soft interface
714  * @hard_iface: hard interface to add to soft interface
715  * @net: the applicable net namespace
716  * @iface_name: name of the soft interface
717  *
718  * Return: 0 on success or negative error number in case of failure
719  */
720 int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
721                                    struct net *net, const char *iface_name)
722 {
723         struct batadv_priv *bat_priv;
724         struct net_device *soft_iface, *master;
725         __be16 ethertype = htons(ETH_P_BATMAN);
726         int max_header_len = batadv_max_header_len();
727         int ret;
728 
729         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
730                 goto out;
731 
732         kref_get(&hard_iface->refcount);
733 
734         soft_iface = dev_get_by_name(net, iface_name);
735 
736         if (!soft_iface) {
737                 soft_iface = batadv_softif_create(net, iface_name);
738 
739                 if (!soft_iface) {
740                         ret = -ENOMEM;
741                         goto err;
742                 }
743 
744                 /* dev_get_by_name() increases the reference counter for us */
745                 dev_hold(soft_iface);
746         }
747 
748         if (!batadv_softif_is_valid(soft_iface)) {
749                 pr_err("Can't create batman mesh interface %s: already exists as regular interface\n",
750                        soft_iface->name);
751                 ret = -EINVAL;
752                 goto err_dev;
753         }
754 
755         /* check if the interface is enslaved in another virtual one and
756          * in that case unlink it first
757          */
758         master = netdev_master_upper_dev_get(hard_iface->net_dev);
759         ret = batadv_master_del_slave(hard_iface, master);
760         if (ret)
761                 goto err_dev;
762 
763         hard_iface->soft_iface = soft_iface;
764         bat_priv = netdev_priv(hard_iface->soft_iface);
765 
766         if (bat_priv->num_ifaces >= UINT_MAX) {
767                 ret = -ENOSPC;
768                 goto err_dev;
769         }
770 
771         ret = netdev_master_upper_dev_link(hard_iface->net_dev,
772                                            soft_iface, NULL, NULL, NULL);
773         if (ret)
774                 goto err_dev;
775 
776         ret = bat_priv->algo_ops->iface.enable(hard_iface);
777         if (ret < 0)
778                 goto err_upper;
779 
780         hard_iface->if_num = bat_priv->num_ifaces;
781         bat_priv->num_ifaces++;
782         hard_iface->if_status = BATADV_IF_INACTIVE;
783         ret = batadv_orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
784         if (ret < 0) {
785                 bat_priv->algo_ops->iface.disable(hard_iface);
786                 bat_priv->num_ifaces--;
787                 hard_iface->if_status = BATADV_IF_NOT_IN_USE;
788                 goto err_upper;
789         }
790 
791         kref_get(&hard_iface->refcount);
792         hard_iface->batman_adv_ptype.type = ethertype;
793         hard_iface->batman_adv_ptype.func = batadv_batman_skb_recv;
794         hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
795         dev_add_pack(&hard_iface->batman_adv_ptype);
796 
797         batadv_info(hard_iface->soft_iface, "Adding interface: %s\n",
798                     hard_iface->net_dev->name);
799 
800         if (atomic_read(&bat_priv->fragmentation) &&
801             hard_iface->net_dev->mtu < ETH_DATA_LEN + max_header_len)
802                 batadv_info(hard_iface->soft_iface,
803                             "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to %i would solve the problem.\n",
804                             hard_iface->net_dev->name, hard_iface->net_dev->mtu,
805                             ETH_DATA_LEN + max_header_len);
806 
807         if (!atomic_read(&bat_priv->fragmentation) &&
808             hard_iface->net_dev->mtu < ETH_DATA_LEN + max_header_len)
809                 batadv_info(hard_iface->soft_iface,
810                             "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. If you experience problems getting traffic through try increasing the MTU to %i.\n",
811                             hard_iface->net_dev->name, hard_iface->net_dev->mtu,
812                             ETH_DATA_LEN + max_header_len);
813 
814         if (batadv_hardif_is_iface_up(hard_iface))
815                 batadv_hardif_activate_interface(hard_iface);
816         else
817                 batadv_err(hard_iface->soft_iface,
818                            "Not using interface %s (retrying later): interface not active\n",
819                            hard_iface->net_dev->name);
820 
821         batadv_hardif_recalc_extra_skbroom(soft_iface);
822 
823 out:
824         return 0;
825 
826 err_upper:
827         netdev_upper_dev_unlink(hard_iface->net_dev, soft_iface);
828 err_dev:
829         hard_iface->soft_iface = NULL;
830         dev_put(soft_iface);
831 err:
832         batadv_hardif_put(hard_iface);
833         return ret;
834 }
835 
836 /**
837  * batadv_hardif_disable_interface() - Remove hard interface from soft interface
838  * @hard_iface: hard interface to be removed
839  * @autodel: whether to delete soft interface when it doesn't contain any other
840  *  slave interfaces
841  */
842 void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface,
843                                      enum batadv_hard_if_cleanup autodel)
844 {
845         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
846         struct batadv_hard_iface *primary_if = NULL;
847 
848         batadv_hardif_deactivate_interface(hard_iface);
849 
850         if (hard_iface->if_status != BATADV_IF_INACTIVE)
851                 goto out;
852 
853         batadv_info(hard_iface->soft_iface, "Removing interface: %s\n",
854                     hard_iface->net_dev->name);
855         dev_remove_pack(&hard_iface->batman_adv_ptype);
856         batadv_hardif_put(hard_iface);
857 
858         bat_priv->num_ifaces--;
859         batadv_orig_hash_del_if(hard_iface, bat_priv->num_ifaces);
860 
861         primary_if = batadv_primary_if_get_selected(bat_priv);
862         if (hard_iface == primary_if) {
863                 struct batadv_hard_iface *new_if;
864 
865                 new_if = batadv_hardif_get_active(hard_iface->soft_iface);
866                 batadv_primary_if_select(bat_priv, new_if);
867 
868                 if (new_if)
869                         batadv_hardif_put(new_if);
870         }
871 
872         bat_priv->algo_ops->iface.disable(hard_iface);
873         hard_iface->if_status = BATADV_IF_NOT_IN_USE;
874 
875         /* delete all references to this hard_iface */
876         batadv_purge_orig_ref(bat_priv);
877         batadv_purge_outstanding_packets(bat_priv, hard_iface);
878         dev_put(hard_iface->soft_iface);
879 
880         netdev_upper_dev_unlink(hard_iface->net_dev, hard_iface->soft_iface);
881         batadv_hardif_recalc_extra_skbroom(hard_iface->soft_iface);
882 
883         /* nobody uses this interface anymore */
884         if (bat_priv->num_ifaces == 0) {
885                 batadv_gw_check_client_stop(bat_priv);
886 
887                 if (autodel == BATADV_IF_CLEANUP_AUTO)
888                         batadv_softif_destroy_sysfs(hard_iface->soft_iface);
889         }
890 
891         hard_iface->soft_iface = NULL;
892         batadv_hardif_put(hard_iface);
893 
894 out:
895         if (primary_if)
896                 batadv_hardif_put(primary_if);
897 }
898 
899 static struct batadv_hard_iface *
900 batadv_hardif_add_interface(struct net_device *net_dev)
901 {
902         struct batadv_hard_iface *hard_iface;
903         int ret;
904 
905         ASSERT_RTNL();
906 
907         if (!batadv_is_valid_iface(net_dev))
908                 goto out;
909 
910         dev_hold(net_dev);
911 
912         hard_iface = kzalloc(sizeof(*hard_iface), GFP_ATOMIC);
913         if (!hard_iface)
914                 goto release_dev;
915 
916         ret = batadv_sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
917         if (ret)
918                 goto free_if;
919 
920         hard_iface->if_num = 0;
921         hard_iface->net_dev = net_dev;
922         hard_iface->soft_iface = NULL;
923         hard_iface->if_status = BATADV_IF_NOT_IN_USE;
924 
925         ret = batadv_debugfs_add_hardif(hard_iface);
926         if (ret)
927                 goto free_sysfs;
928 
929         INIT_LIST_HEAD(&hard_iface->list);
930         INIT_HLIST_HEAD(&hard_iface->neigh_list);
931 
932         spin_lock_init(&hard_iface->neigh_list_lock);
933         kref_init(&hard_iface->refcount);
934 
935         hard_iface->num_bcasts = BATADV_NUM_BCASTS_DEFAULT;
936         hard_iface->wifi_flags = batadv_wifi_flags_evaluate(net_dev);
937         if (batadv_is_wifi_hardif(hard_iface))
938                 hard_iface->num_bcasts = BATADV_NUM_BCASTS_WIRELESS;
939 
940         batadv_v_hardif_init(hard_iface);
941 
942         batadv_check_known_mac_addr(hard_iface->net_dev);
943         kref_get(&hard_iface->refcount);
944         list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);
945 
946         return hard_iface;
947 
948 free_sysfs:
949         batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
950 free_if:
951         kfree(hard_iface);
952 release_dev:
953         dev_put(net_dev);
954 out:
955         return NULL;
956 }
957 
958 static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)
959 {
960         ASSERT_RTNL();
961 
962         /* first deactivate interface */
963         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
964                 batadv_hardif_disable_interface(hard_iface,
965                                                 BATADV_IF_CLEANUP_KEEP);
966 
967         if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
968                 return;
969 
970         hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
971         batadv_debugfs_del_hardif(hard_iface);
972         batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
973         batadv_hardif_put(hard_iface);
974 }
975 
976 /**
977  * batadv_hardif_remove_interfaces() - Remove all hard interfaces
978  */
979 void batadv_hardif_remove_interfaces(void)
980 {
981         struct batadv_hard_iface *hard_iface, *hard_iface_tmp;
982 
983         rtnl_lock();
984         list_for_each_entry_safe(hard_iface, hard_iface_tmp,
985                                  &batadv_hardif_list, list) {
986                 list_del_rcu(&hard_iface->list);
987                 batadv_hardif_remove_interface(hard_iface);
988         }
989         rtnl_unlock();
990 }
991 
992 static int batadv_hard_if_event(struct notifier_block *this,
993                                 unsigned long event, void *ptr)
994 {
995         struct net_device *net_dev = netdev_notifier_info_to_dev(ptr);
996         struct batadv_hard_iface *hard_iface;
997         struct batadv_hard_iface *primary_if = NULL;
998         struct batadv_priv *bat_priv;
999 
1000         if (batadv_softif_is_valid(net_dev) && event == NETDEV_REGISTER) {
1001                 batadv_sysfs_add_meshif(net_dev);
1002                 bat_priv = netdev_priv(net_dev);
1003                 batadv_softif_create_vlan(bat_priv, BATADV_NO_FLAGS);
1004                 return NOTIFY_DONE;
1005         }
1006 
1007         hard_iface = batadv_hardif_get_by_netdev(net_dev);
1008         if (!hard_iface && (event == NETDEV_REGISTER ||
1009                             event == NETDEV_POST_TYPE_CHANGE))
1010                 hard_iface = batadv_hardif_add_interface(net_dev);
1011 
1012         if (!hard_iface)
1013                 goto out;
1014 
1015         switch (event) {
1016         case NETDEV_UP:
1017                 batadv_hardif_activate_interface(hard_iface);
1018                 break;
1019         case NETDEV_GOING_DOWN:
1020         case NETDEV_DOWN:
1021                 batadv_hardif_deactivate_interface(hard_iface);
1022                 break;
1023         case NETDEV_UNREGISTER:
1024         case NETDEV_PRE_TYPE_CHANGE:
1025                 list_del_rcu(&hard_iface->list);
1026 
1027                 batadv_hardif_remove_interface(hard_iface);
1028                 break;
1029         case NETDEV_CHANGEMTU:
1030                 if (hard_iface->soft_iface)
1031                         batadv_update_min_mtu(hard_iface->soft_iface);
1032                 break;
1033         case NETDEV_CHANGEADDR:
1034                 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
1035                         goto hardif_put;
1036 
1037                 batadv_check_known_mac_addr(hard_iface->net_dev);
1038 
1039                 bat_priv = netdev_priv(hard_iface->soft_iface);
1040                 bat_priv->algo_ops->iface.update_mac(hard_iface);
1041 
1042                 primary_if = batadv_primary_if_get_selected(bat_priv);
1043                 if (!primary_if)
1044                         goto hardif_put;
1045 
1046                 if (hard_iface == primary_if)
1047                         batadv_primary_if_update_addr(bat_priv, NULL);
1048                 break;
1049         case NETDEV_CHANGEUPPER:
1050                 hard_iface->wifi_flags = batadv_wifi_flags_evaluate(net_dev);
1051                 if (batadv_is_wifi_hardif(hard_iface))
1052                         hard_iface->num_bcasts = BATADV_NUM_BCASTS_WIRELESS;
1053                 break;
1054         default:
1055                 break;
1056         }
1057 
1058 hardif_put:
1059         batadv_hardif_put(hard_iface);
1060 out:
1061         if (primary_if)
1062                 batadv_hardif_put(primary_if);
1063         return NOTIFY_DONE;
1064 }
1065 
1066 struct notifier_block batadv_hard_if_notifier = {
1067         .notifier_call = batadv_hard_if_event,
1068 };
1069 

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