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Linux/net/mac80211/mesh_pathtbl.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * Copyright (c) 2008, 2009 open80211s Ltd.
  4  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
  5  */
  6 
  7 #include <linux/etherdevice.h>
  8 #include <linux/list.h>
  9 #include <linux/random.h>
 10 #include <linux/slab.h>
 11 #include <linux/spinlock.h>
 12 #include <linux/string.h>
 13 #include <net/mac80211.h>
 14 #include "wme.h"
 15 #include "ieee80211_i.h"
 16 #include "mesh.h"
 17 
 18 static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);
 19 
 20 static u32 mesh_table_hash(const void *addr, u32 len, u32 seed)
 21 {
 22         /* Use last four bytes of hw addr as hash index */
 23         return jhash_1word(__get_unaligned_cpu32((u8 *)addr + 2), seed);
 24 }
 25 
 26 static const struct rhashtable_params mesh_rht_params = {
 27         .nelem_hint = 2,
 28         .automatic_shrinking = true,
 29         .key_len = ETH_ALEN,
 30         .key_offset = offsetof(struct mesh_path, dst),
 31         .head_offset = offsetof(struct mesh_path, rhash),
 32         .hashfn = mesh_table_hash,
 33 };
 34 
 35 static inline bool mpath_expired(struct mesh_path *mpath)
 36 {
 37         return (mpath->flags & MESH_PATH_ACTIVE) &&
 38                time_after(jiffies, mpath->exp_time) &&
 39                !(mpath->flags & MESH_PATH_FIXED);
 40 }
 41 
 42 static void mesh_path_rht_free(void *ptr, void *tblptr)
 43 {
 44         struct mesh_path *mpath = ptr;
 45         struct mesh_table *tbl = tblptr;
 46 
 47         mesh_path_free_rcu(tbl, mpath);
 48 }
 49 
 50 static struct mesh_table *mesh_table_alloc(void)
 51 {
 52         struct mesh_table *newtbl;
 53 
 54         newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
 55         if (!newtbl)
 56                 return NULL;
 57 
 58         INIT_HLIST_HEAD(&newtbl->known_gates);
 59         INIT_HLIST_HEAD(&newtbl->walk_head);
 60         atomic_set(&newtbl->entries,  0);
 61         spin_lock_init(&newtbl->gates_lock);
 62         spin_lock_init(&newtbl->walk_lock);
 63 
 64         return newtbl;
 65 }
 66 
 67 static void mesh_table_free(struct mesh_table *tbl)
 68 {
 69         rhashtable_free_and_destroy(&tbl->rhead,
 70                                     mesh_path_rht_free, tbl);
 71         kfree(tbl);
 72 }
 73 
 74 /**
 75  *
 76  * mesh_path_assign_nexthop - update mesh path next hop
 77  *
 78  * @mpath: mesh path to update
 79  * @sta: next hop to assign
 80  *
 81  * Locking: mpath->state_lock must be held when calling this function
 82  */
 83 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 84 {
 85         struct sk_buff *skb;
 86         struct ieee80211_hdr *hdr;
 87         unsigned long flags;
 88 
 89         rcu_assign_pointer(mpath->next_hop, sta);
 90 
 91         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 92         skb_queue_walk(&mpath->frame_queue, skb) {
 93                 hdr = (struct ieee80211_hdr *) skb->data;
 94                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 95                 memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
 96                 ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
 97         }
 98 
 99         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
100 }
101 
102 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
103                              struct mesh_path *gate_mpath)
104 {
105         struct ieee80211_hdr *hdr;
106         struct ieee80211s_hdr *mshdr;
107         int mesh_hdrlen, hdrlen;
108         char *next_hop;
109 
110         hdr = (struct ieee80211_hdr *) skb->data;
111         hdrlen = ieee80211_hdrlen(hdr->frame_control);
112         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
113 
114         if (!(mshdr->flags & MESH_FLAGS_AE)) {
115                 /* size of the fixed part of the mesh header */
116                 mesh_hdrlen = 6;
117 
118                 /* make room for the two extended addresses */
119                 skb_push(skb, 2 * ETH_ALEN);
120                 memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
121 
122                 hdr = (struct ieee80211_hdr *) skb->data;
123 
124                 /* we preserve the previous mesh header and only add
125                  * the new addreses */
126                 mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
127                 mshdr->flags = MESH_FLAGS_AE_A5_A6;
128                 memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
129                 memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
130         }
131 
132         /* update next hop */
133         hdr = (struct ieee80211_hdr *) skb->data;
134         rcu_read_lock();
135         next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
136         memcpy(hdr->addr1, next_hop, ETH_ALEN);
137         rcu_read_unlock();
138         memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
139         memcpy(hdr->addr3, dst_addr, ETH_ALEN);
140 }
141 
142 /**
143  *
144  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
145  *
146  * This function is used to transfer or copy frames from an unresolved mpath to
147  * a gate mpath.  The function also adds the Address Extension field and
148  * updates the next hop.
149  *
150  * If a frame already has an Address Extension field, only the next hop and
151  * destination addresses are updated.
152  *
153  * The gate mpath must be an active mpath with a valid mpath->next_hop.
154  *
155  * @mpath: An active mpath the frames will be sent to (i.e. the gate)
156  * @from_mpath: The failed mpath
157  * @copy: When true, copy all the frames to the new mpath queue.  When false,
158  * move them.
159  */
160 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
161                                     struct mesh_path *from_mpath,
162                                     bool copy)
163 {
164         struct sk_buff *skb, *fskb, *tmp;
165         struct sk_buff_head failq;
166         unsigned long flags;
167 
168         if (WARN_ON(gate_mpath == from_mpath))
169                 return;
170         if (WARN_ON(!gate_mpath->next_hop))
171                 return;
172 
173         __skb_queue_head_init(&failq);
174 
175         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
176         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
177         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
178 
179         skb_queue_walk_safe(&failq, fskb, tmp) {
180                 if (skb_queue_len(&gate_mpath->frame_queue) >=
181                                   MESH_FRAME_QUEUE_LEN) {
182                         mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
183                         break;
184                 }
185 
186                 skb = skb_copy(fskb, GFP_ATOMIC);
187                 if (WARN_ON(!skb))
188                         break;
189 
190                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
191                 skb_queue_tail(&gate_mpath->frame_queue, skb);
192 
193                 if (copy)
194                         continue;
195 
196                 __skb_unlink(fskb, &failq);
197                 kfree_skb(fskb);
198         }
199 
200         mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
201                   gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
202 
203         if (!copy)
204                 return;
205 
206         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
207         skb_queue_splice(&failq, &from_mpath->frame_queue);
208         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
209 }
210 
211 
212 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
213                                       struct ieee80211_sub_if_data *sdata)
214 {
215         struct mesh_path *mpath;
216 
217         mpath = rhashtable_lookup(&tbl->rhead, dst, mesh_rht_params);
218 
219         if (mpath && mpath_expired(mpath)) {
220                 spin_lock_bh(&mpath->state_lock);
221                 mpath->flags &= ~MESH_PATH_ACTIVE;
222                 spin_unlock_bh(&mpath->state_lock);
223         }
224         return mpath;
225 }
226 
227 /**
228  * mesh_path_lookup - look up a path in the mesh path table
229  * @sdata: local subif
230  * @dst: hardware address (ETH_ALEN length) of destination
231  *
232  * Returns: pointer to the mesh path structure, or NULL if not found
233  *
234  * Locking: must be called within a read rcu section.
235  */
236 struct mesh_path *
237 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
238 {
239         return mpath_lookup(sdata->u.mesh.mesh_paths, dst, sdata);
240 }
241 
242 struct mesh_path *
243 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
244 {
245         return mpath_lookup(sdata->u.mesh.mpp_paths, dst, sdata);
246 }
247 
248 static struct mesh_path *
249 __mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
250 {
251         int i = 0;
252         struct mesh_path *mpath;
253 
254         hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
255                 if (i++ == idx)
256                         break;
257         }
258 
259         if (!mpath)
260                 return NULL;
261 
262         if (mpath_expired(mpath)) {
263                 spin_lock_bh(&mpath->state_lock);
264                 mpath->flags &= ~MESH_PATH_ACTIVE;
265                 spin_unlock_bh(&mpath->state_lock);
266         }
267         return mpath;
268 }
269 
270 /**
271  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
272  * @idx: index
273  * @sdata: local subif, or NULL for all entries
274  *
275  * Returns: pointer to the mesh path structure, or NULL if not found.
276  *
277  * Locking: must be called within a read rcu section.
278  */
279 struct mesh_path *
280 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
281 {
282         return __mesh_path_lookup_by_idx(sdata->u.mesh.mesh_paths, idx);
283 }
284 
285 /**
286  * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
287  * @idx: index
288  * @sdata: local subif, or NULL for all entries
289  *
290  * Returns: pointer to the proxy path structure, or NULL if not found.
291  *
292  * Locking: must be called within a read rcu section.
293  */
294 struct mesh_path *
295 mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
296 {
297         return __mesh_path_lookup_by_idx(sdata->u.mesh.mpp_paths, idx);
298 }
299 
300 /**
301  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
302  * @mpath: gate path to add to table
303  */
304 int mesh_path_add_gate(struct mesh_path *mpath)
305 {
306         struct mesh_table *tbl;
307         int err;
308 
309         rcu_read_lock();
310         tbl = mpath->sdata->u.mesh.mesh_paths;
311 
312         spin_lock_bh(&mpath->state_lock);
313         if (mpath->is_gate) {
314                 err = -EEXIST;
315                 spin_unlock_bh(&mpath->state_lock);
316                 goto err_rcu;
317         }
318         mpath->is_gate = true;
319         mpath->sdata->u.mesh.num_gates++;
320 
321         spin_lock(&tbl->gates_lock);
322         hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
323         spin_unlock(&tbl->gates_lock);
324 
325         spin_unlock_bh(&mpath->state_lock);
326 
327         mpath_dbg(mpath->sdata,
328                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
329                   mpath->dst, mpath->sdata->u.mesh.num_gates);
330         err = 0;
331 err_rcu:
332         rcu_read_unlock();
333         return err;
334 }
335 
336 /**
337  * mesh_gate_del - remove a mesh gate from the list of known gates
338  * @tbl: table which holds our list of known gates
339  * @mpath: gate mpath
340  */
341 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
342 {
343         lockdep_assert_held(&mpath->state_lock);
344         if (!mpath->is_gate)
345                 return;
346 
347         mpath->is_gate = false;
348         spin_lock_bh(&tbl->gates_lock);
349         hlist_del_rcu(&mpath->gate_list);
350         mpath->sdata->u.mesh.num_gates--;
351         spin_unlock_bh(&tbl->gates_lock);
352 
353         mpath_dbg(mpath->sdata,
354                   "Mesh path: Deleted gate: %pM. %d known gates\n",
355                   mpath->dst, mpath->sdata->u.mesh.num_gates);
356 }
357 
358 /**
359  * mesh_gate_num - number of gates known to this interface
360  * @sdata: subif data
361  */
362 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
363 {
364         return sdata->u.mesh.num_gates;
365 }
366 
367 static
368 struct mesh_path *mesh_path_new(struct ieee80211_sub_if_data *sdata,
369                                 const u8 *dst, gfp_t gfp_flags)
370 {
371         struct mesh_path *new_mpath;
372 
373         new_mpath = kzalloc(sizeof(struct mesh_path), gfp_flags);
374         if (!new_mpath)
375                 return NULL;
376 
377         memcpy(new_mpath->dst, dst, ETH_ALEN);
378         eth_broadcast_addr(new_mpath->rann_snd_addr);
379         new_mpath->is_root = false;
380         new_mpath->sdata = sdata;
381         new_mpath->flags = 0;
382         skb_queue_head_init(&new_mpath->frame_queue);
383         new_mpath->exp_time = jiffies;
384         spin_lock_init(&new_mpath->state_lock);
385         timer_setup(&new_mpath->timer, mesh_path_timer, 0);
386 
387         return new_mpath;
388 }
389 
390 /**
391  * mesh_path_add - allocate and add a new path to the mesh path table
392  * @dst: destination address of the path (ETH_ALEN length)
393  * @sdata: local subif
394  *
395  * Returns: 0 on success
396  *
397  * State: the initial state of the new path is set to 0
398  */
399 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
400                                 const u8 *dst)
401 {
402         struct mesh_table *tbl;
403         struct mesh_path *mpath, *new_mpath;
404 
405         if (ether_addr_equal(dst, sdata->vif.addr))
406                 /* never add ourselves as neighbours */
407                 return ERR_PTR(-ENOTSUPP);
408 
409         if (is_multicast_ether_addr(dst))
410                 return ERR_PTR(-ENOTSUPP);
411 
412         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
413                 return ERR_PTR(-ENOSPC);
414 
415         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
416         if (!new_mpath)
417                 return ERR_PTR(-ENOMEM);
418 
419         tbl = sdata->u.mesh.mesh_paths;
420         spin_lock_bh(&tbl->walk_lock);
421         mpath = rhashtable_lookup_get_insert_fast(&tbl->rhead,
422                                                   &new_mpath->rhash,
423                                                   mesh_rht_params);
424         if (!mpath)
425                 hlist_add_head(&new_mpath->walk_list, &tbl->walk_head);
426         spin_unlock_bh(&tbl->walk_lock);
427 
428         if (mpath) {
429                 kfree(new_mpath);
430 
431                 if (IS_ERR(mpath))
432                         return mpath;
433 
434                 new_mpath = mpath;
435         }
436 
437         sdata->u.mesh.mesh_paths_generation++;
438         return new_mpath;
439 }
440 
441 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
442                  const u8 *dst, const u8 *mpp)
443 {
444         struct mesh_table *tbl;
445         struct mesh_path *new_mpath;
446         int ret;
447 
448         if (ether_addr_equal(dst, sdata->vif.addr))
449                 /* never add ourselves as neighbours */
450                 return -ENOTSUPP;
451 
452         if (is_multicast_ether_addr(dst))
453                 return -ENOTSUPP;
454 
455         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
456 
457         if (!new_mpath)
458                 return -ENOMEM;
459 
460         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
461         tbl = sdata->u.mesh.mpp_paths;
462 
463         spin_lock_bh(&tbl->walk_lock);
464         ret = rhashtable_lookup_insert_fast(&tbl->rhead,
465                                             &new_mpath->rhash,
466                                             mesh_rht_params);
467         if (!ret)
468                 hlist_add_head_rcu(&new_mpath->walk_list, &tbl->walk_head);
469         spin_unlock_bh(&tbl->walk_lock);
470 
471         if (ret)
472                 kfree(new_mpath);
473 
474         sdata->u.mesh.mpp_paths_generation++;
475         return ret;
476 }
477 
478 
479 /**
480  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
481  *
482  * @sta: broken peer link
483  *
484  * This function must be called from the rate control algorithm if enough
485  * delivery errors suggest that a peer link is no longer usable.
486  */
487 void mesh_plink_broken(struct sta_info *sta)
488 {
489         struct ieee80211_sub_if_data *sdata = sta->sdata;
490         struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
491         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
492         struct mesh_path *mpath;
493 
494         rcu_read_lock();
495         hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
496                 if (rcu_access_pointer(mpath->next_hop) == sta &&
497                     mpath->flags & MESH_PATH_ACTIVE &&
498                     !(mpath->flags & MESH_PATH_FIXED)) {
499                         spin_lock_bh(&mpath->state_lock);
500                         mpath->flags &= ~MESH_PATH_ACTIVE;
501                         ++mpath->sn;
502                         spin_unlock_bh(&mpath->state_lock);
503                         mesh_path_error_tx(sdata,
504                                 sdata->u.mesh.mshcfg.element_ttl,
505                                 mpath->dst, mpath->sn,
506                                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
507                 }
508         }
509         rcu_read_unlock();
510 }
511 
512 static void mesh_path_free_rcu(struct mesh_table *tbl,
513                                struct mesh_path *mpath)
514 {
515         struct ieee80211_sub_if_data *sdata = mpath->sdata;
516 
517         spin_lock_bh(&mpath->state_lock);
518         mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
519         mesh_gate_del(tbl, mpath);
520         spin_unlock_bh(&mpath->state_lock);
521         del_timer_sync(&mpath->timer);
522         atomic_dec(&sdata->u.mesh.mpaths);
523         atomic_dec(&tbl->entries);
524         mesh_path_flush_pending(mpath);
525         kfree_rcu(mpath, rcu);
526 }
527 
528 static void __mesh_path_del(struct mesh_table *tbl, struct mesh_path *mpath)
529 {
530         hlist_del_rcu(&mpath->walk_list);
531         rhashtable_remove_fast(&tbl->rhead, &mpath->rhash, mesh_rht_params);
532         mesh_path_free_rcu(tbl, mpath);
533 }
534 
535 /**
536  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
537  *
538  * @sta: mesh peer to match
539  *
540  * RCU notes: this function is called when a mesh plink transitions from
541  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
542  * allows path creation. This will happen before the sta can be freed (because
543  * sta_info_destroy() calls this) so any reader in a rcu read block will be
544  * protected against the plink disappearing.
545  */
546 void mesh_path_flush_by_nexthop(struct sta_info *sta)
547 {
548         struct ieee80211_sub_if_data *sdata = sta->sdata;
549         struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
550         struct mesh_path *mpath;
551         struct hlist_node *n;
552 
553         spin_lock_bh(&tbl->walk_lock);
554         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
555                 if (rcu_access_pointer(mpath->next_hop) == sta)
556                         __mesh_path_del(tbl, mpath);
557         }
558         spin_unlock_bh(&tbl->walk_lock);
559 }
560 
561 static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
562                                const u8 *proxy)
563 {
564         struct mesh_table *tbl = sdata->u.mesh.mpp_paths;
565         struct mesh_path *mpath;
566         struct hlist_node *n;
567 
568         spin_lock_bh(&tbl->walk_lock);
569         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
570                 if (ether_addr_equal(mpath->mpp, proxy))
571                         __mesh_path_del(tbl, mpath);
572         }
573         spin_unlock_bh(&tbl->walk_lock);
574 }
575 
576 static void table_flush_by_iface(struct mesh_table *tbl)
577 {
578         struct mesh_path *mpath;
579         struct hlist_node *n;
580 
581         spin_lock_bh(&tbl->walk_lock);
582         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
583                 __mesh_path_del(tbl, mpath);
584         }
585         spin_unlock_bh(&tbl->walk_lock);
586 }
587 
588 /**
589  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
590  *
591  * This function deletes both mesh paths as well as mesh portal paths.
592  *
593  * @sdata: interface data to match
594  *
595  */
596 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
597 {
598         table_flush_by_iface(sdata->u.mesh.mesh_paths);
599         table_flush_by_iface(sdata->u.mesh.mpp_paths);
600 }
601 
602 /**
603  * table_path_del - delete a path from the mesh or mpp table
604  *
605  * @tbl: mesh or mpp path table
606  * @sdata: local subif
607  * @addr: dst address (ETH_ALEN length)
608  *
609  * Returns: 0 if successful
610  */
611 static int table_path_del(struct mesh_table *tbl,
612                           struct ieee80211_sub_if_data *sdata,
613                           const u8 *addr)
614 {
615         struct mesh_path *mpath;
616 
617         spin_lock_bh(&tbl->walk_lock);
618         mpath = rhashtable_lookup_fast(&tbl->rhead, addr, mesh_rht_params);
619         if (!mpath) {
620                 spin_unlock_bh(&tbl->walk_lock);
621                 return -ENXIO;
622         }
623 
624         __mesh_path_del(tbl, mpath);
625         spin_unlock_bh(&tbl->walk_lock);
626         return 0;
627 }
628 
629 
630 /**
631  * mesh_path_del - delete a mesh path from the table
632  *
633  * @addr: dst address (ETH_ALEN length)
634  * @sdata: local subif
635  *
636  * Returns: 0 if successful
637  */
638 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
639 {
640         int err;
641 
642         /* flush relevant mpp entries first */
643         mpp_flush_by_proxy(sdata, addr);
644 
645         err = table_path_del(sdata->u.mesh.mesh_paths, sdata, addr);
646         sdata->u.mesh.mesh_paths_generation++;
647         return err;
648 }
649 
650 /**
651  * mesh_path_tx_pending - sends pending frames in a mesh path queue
652  *
653  * @mpath: mesh path to activate
654  *
655  * Locking: the state_lock of the mpath structure must NOT be held when calling
656  * this function.
657  */
658 void mesh_path_tx_pending(struct mesh_path *mpath)
659 {
660         if (mpath->flags & MESH_PATH_ACTIVE)
661                 ieee80211_add_pending_skbs(mpath->sdata->local,
662                                 &mpath->frame_queue);
663 }
664 
665 /**
666  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
667  *
668  * @mpath: mesh path whose queue will be emptied
669  *
670  * If there is only one gate, the frames are transferred from the failed mpath
671  * queue to that gate's queue.  If there are more than one gates, the frames
672  * are copied from each gate to the next.  After frames are copied, the
673  * mpath queues are emptied onto the transmission queue.
674  */
675 int mesh_path_send_to_gates(struct mesh_path *mpath)
676 {
677         struct ieee80211_sub_if_data *sdata = mpath->sdata;
678         struct mesh_table *tbl;
679         struct mesh_path *from_mpath = mpath;
680         struct mesh_path *gate;
681         bool copy = false;
682 
683         tbl = sdata->u.mesh.mesh_paths;
684 
685         rcu_read_lock();
686         hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
687                 if (gate->flags & MESH_PATH_ACTIVE) {
688                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->dst);
689                         mesh_path_move_to_queue(gate, from_mpath, copy);
690                         from_mpath = gate;
691                         copy = true;
692                 } else {
693                         mpath_dbg(sdata,
694                                   "Not forwarding to %pM (flags %#x)\n",
695                                   gate->dst, gate->flags);
696                 }
697         }
698 
699         hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
700                 mpath_dbg(sdata, "Sending to %pM\n", gate->dst);
701                 mesh_path_tx_pending(gate);
702         }
703         rcu_read_unlock();
704 
705         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
706 }
707 
708 /**
709  * mesh_path_discard_frame - discard a frame whose path could not be resolved
710  *
711  * @skb: frame to discard
712  * @sdata: network subif the frame was to be sent through
713  *
714  * Locking: the function must me called within a rcu_read_lock region
715  */
716 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
717                              struct sk_buff *skb)
718 {
719         kfree_skb(skb);
720         sdata->u.mesh.mshstats.dropped_frames_no_route++;
721 }
722 
723 /**
724  * mesh_path_flush_pending - free the pending queue of a mesh path
725  *
726  * @mpath: mesh path whose queue has to be freed
727  *
728  * Locking: the function must me called within a rcu_read_lock region
729  */
730 void mesh_path_flush_pending(struct mesh_path *mpath)
731 {
732         struct sk_buff *skb;
733 
734         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
735                 mesh_path_discard_frame(mpath->sdata, skb);
736 }
737 
738 /**
739  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
740  *
741  * @mpath: the mesh path to modify
742  * @next_hop: the next hop to force
743  *
744  * Locking: this function must be called holding mpath->state_lock
745  */
746 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
747 {
748         spin_lock_bh(&mpath->state_lock);
749         mesh_path_assign_nexthop(mpath, next_hop);
750         mpath->sn = 0xffff;
751         mpath->metric = 0;
752         mpath->hop_count = 0;
753         mpath->exp_time = 0;
754         mpath->flags = MESH_PATH_FIXED | MESH_PATH_SN_VALID;
755         mesh_path_activate(mpath);
756         spin_unlock_bh(&mpath->state_lock);
757         ewma_mesh_fail_avg_init(&next_hop->mesh->fail_avg);
758         /* init it at a low value - 0 start is tricky */
759         ewma_mesh_fail_avg_add(&next_hop->mesh->fail_avg, 1);
760         mesh_path_tx_pending(mpath);
761 }
762 
763 int mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
764 {
765         struct mesh_table *tbl_path, *tbl_mpp;
766         int ret;
767 
768         tbl_path = mesh_table_alloc();
769         if (!tbl_path)
770                 return -ENOMEM;
771 
772         tbl_mpp = mesh_table_alloc();
773         if (!tbl_mpp) {
774                 ret = -ENOMEM;
775                 goto free_path;
776         }
777 
778         rhashtable_init(&tbl_path->rhead, &mesh_rht_params);
779         rhashtable_init(&tbl_mpp->rhead, &mesh_rht_params);
780 
781         sdata->u.mesh.mesh_paths = tbl_path;
782         sdata->u.mesh.mpp_paths = tbl_mpp;
783 
784         return 0;
785 
786 free_path:
787         mesh_table_free(tbl_path);
788         return ret;
789 }
790 
791 static
792 void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
793                           struct mesh_table *tbl)
794 {
795         struct mesh_path *mpath;
796         struct hlist_node *n;
797 
798         spin_lock_bh(&tbl->walk_lock);
799         hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
800                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
801                     (!(mpath->flags & MESH_PATH_FIXED)) &&
802                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
803                         __mesh_path_del(tbl, mpath);
804         }
805         spin_unlock_bh(&tbl->walk_lock);
806 }
807 
808 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
809 {
810         mesh_path_tbl_expire(sdata, sdata->u.mesh.mesh_paths);
811         mesh_path_tbl_expire(sdata, sdata->u.mesh.mpp_paths);
812 }
813 
814 void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
815 {
816         mesh_table_free(sdata->u.mesh.mesh_paths);
817         mesh_table_free(sdata->u.mesh.mpp_paths);
818 }
819 

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