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Linux/net/mac80211/mesh_pathtbl.c

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  1 /*
  2  * Copyright (c) 2008, 2009 open80211s Ltd.
  3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
  4  *
  5  * This program is free software; you can redistribute it and/or modify
  6  * it under the terms of the GNU General Public License version 2 as
  7  * published by the Free Software Foundation.
  8  */
  9 
 10 #include <linux/etherdevice.h>
 11 #include <linux/list.h>
 12 #include <linux/random.h>
 13 #include <linux/slab.h>
 14 #include <linux/spinlock.h>
 15 #include <linux/string.h>
 16 #include <net/mac80211.h>
 17 #include "wme.h"
 18 #include "ieee80211_i.h"
 19 #include "mesh.h"
 20 
 21 static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);
 22 
 23 static u32 mesh_table_hash(const void *addr, u32 len, u32 seed)
 24 {
 25         /* Use last four bytes of hw addr as hash index */
 26         return jhash_1word(*(u32 *)(addr+2), seed);
 27 }
 28 
 29 static const struct rhashtable_params mesh_rht_params = {
 30         .nelem_hint = 2,
 31         .automatic_shrinking = true,
 32         .key_len = ETH_ALEN,
 33         .key_offset = offsetof(struct mesh_path, dst),
 34         .head_offset = offsetof(struct mesh_path, rhash),
 35         .hashfn = mesh_table_hash,
 36 };
 37 
 38 static inline bool mpath_expired(struct mesh_path *mpath)
 39 {
 40         return (mpath->flags & MESH_PATH_ACTIVE) &&
 41                time_after(jiffies, mpath->exp_time) &&
 42                !(mpath->flags & MESH_PATH_FIXED);
 43 }
 44 
 45 static void mesh_path_rht_free(void *ptr, void *tblptr)
 46 {
 47         struct mesh_path *mpath = ptr;
 48         struct mesh_table *tbl = tblptr;
 49 
 50         mesh_path_free_rcu(tbl, mpath);
 51 }
 52 
 53 static struct mesh_table *mesh_table_alloc(void)
 54 {
 55         struct mesh_table *newtbl;
 56 
 57         newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
 58         if (!newtbl)
 59                 return NULL;
 60 
 61         INIT_HLIST_HEAD(&newtbl->known_gates);
 62         atomic_set(&newtbl->entries,  0);
 63         spin_lock_init(&newtbl->gates_lock);
 64 
 65         return newtbl;
 66 }
 67 
 68 static void mesh_table_free(struct mesh_table *tbl)
 69 {
 70         rhashtable_free_and_destroy(&tbl->rhead,
 71                                     mesh_path_rht_free, tbl);
 72         kfree(tbl);
 73 }
 74 
 75 /**
 76  *
 77  * mesh_path_assign_nexthop - update mesh path next hop
 78  *
 79  * @mpath: mesh path to update
 80  * @sta: next hop to assign
 81  *
 82  * Locking: mpath->state_lock must be held when calling this function
 83  */
 84 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 85 {
 86         struct sk_buff *skb;
 87         struct ieee80211_hdr *hdr;
 88         unsigned long flags;
 89 
 90         rcu_assign_pointer(mpath->next_hop, sta);
 91 
 92         spin_lock_irqsave(&mpath->frame_queue.lock, flags);
 93         skb_queue_walk(&mpath->frame_queue, skb) {
 94                 hdr = (struct ieee80211_hdr *) skb->data;
 95                 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
 96                 memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
 97                 ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
 98         }
 99 
100         spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
101 }
102 
103 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
104                              struct mesh_path *gate_mpath)
105 {
106         struct ieee80211_hdr *hdr;
107         struct ieee80211s_hdr *mshdr;
108         int mesh_hdrlen, hdrlen;
109         char *next_hop;
110 
111         hdr = (struct ieee80211_hdr *) skb->data;
112         hdrlen = ieee80211_hdrlen(hdr->frame_control);
113         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
114 
115         if (!(mshdr->flags & MESH_FLAGS_AE)) {
116                 /* size of the fixed part of the mesh header */
117                 mesh_hdrlen = 6;
118 
119                 /* make room for the two extended addresses */
120                 skb_push(skb, 2 * ETH_ALEN);
121                 memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
122 
123                 hdr = (struct ieee80211_hdr *) skb->data;
124 
125                 /* we preserve the previous mesh header and only add
126                  * the new addreses */
127                 mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
128                 mshdr->flags = MESH_FLAGS_AE_A5_A6;
129                 memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
130                 memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
131         }
132 
133         /* update next hop */
134         hdr = (struct ieee80211_hdr *) skb->data;
135         rcu_read_lock();
136         next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
137         memcpy(hdr->addr1, next_hop, ETH_ALEN);
138         rcu_read_unlock();
139         memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
140         memcpy(hdr->addr3, dst_addr, ETH_ALEN);
141 }
142 
143 /**
144  *
145  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
146  *
147  * This function is used to transfer or copy frames from an unresolved mpath to
148  * a gate mpath.  The function also adds the Address Extension field and
149  * updates the next hop.
150  *
151  * If a frame already has an Address Extension field, only the next hop and
152  * destination addresses are updated.
153  *
154  * The gate mpath must be an active mpath with a valid mpath->next_hop.
155  *
156  * @mpath: An active mpath the frames will be sent to (i.e. the gate)
157  * @from_mpath: The failed mpath
158  * @copy: When true, copy all the frames to the new mpath queue.  When false,
159  * move them.
160  */
161 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
162                                     struct mesh_path *from_mpath,
163                                     bool copy)
164 {
165         struct sk_buff *skb, *fskb, *tmp;
166         struct sk_buff_head failq;
167         unsigned long flags;
168 
169         if (WARN_ON(gate_mpath == from_mpath))
170                 return;
171         if (WARN_ON(!gate_mpath->next_hop))
172                 return;
173 
174         __skb_queue_head_init(&failq);
175 
176         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
177         skb_queue_splice_init(&from_mpath->frame_queue, &failq);
178         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
179 
180         skb_queue_walk_safe(&failq, fskb, tmp) {
181                 if (skb_queue_len(&gate_mpath->frame_queue) >=
182                                   MESH_FRAME_QUEUE_LEN) {
183                         mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
184                         break;
185                 }
186 
187                 skb = skb_copy(fskb, GFP_ATOMIC);
188                 if (WARN_ON(!skb))
189                         break;
190 
191                 prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
192                 skb_queue_tail(&gate_mpath->frame_queue, skb);
193 
194                 if (copy)
195                         continue;
196 
197                 __skb_unlink(fskb, &failq);
198                 kfree_skb(fskb);
199         }
200 
201         mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
202                   gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
203 
204         if (!copy)
205                 return;
206 
207         spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
208         skb_queue_splice(&failq, &from_mpath->frame_queue);
209         spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
210 }
211 
212 
213 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
214                                       struct ieee80211_sub_if_data *sdata)
215 {
216         struct mesh_path *mpath;
217 
218         mpath = rhashtable_lookup_fast(&tbl->rhead, dst, mesh_rht_params);
219 
220         if (mpath && mpath_expired(mpath)) {
221                 spin_lock_bh(&mpath->state_lock);
222                 mpath->flags &= ~MESH_PATH_ACTIVE;
223                 spin_unlock_bh(&mpath->state_lock);
224         }
225         return mpath;
226 }
227 
228 /**
229  * mesh_path_lookup - look up a path in the mesh path table
230  * @sdata: local subif
231  * @dst: hardware address (ETH_ALEN length) of destination
232  *
233  * Returns: pointer to the mesh path structure, or NULL if not found
234  *
235  * Locking: must be called within a read rcu section.
236  */
237 struct mesh_path *
238 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
239 {
240         return mpath_lookup(sdata->u.mesh.mesh_paths, dst, sdata);
241 }
242 
243 struct mesh_path *
244 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
245 {
246         return mpath_lookup(sdata->u.mesh.mpp_paths, dst, sdata);
247 }
248 
249 static struct mesh_path *
250 __mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
251 {
252         int i = 0, ret;
253         struct mesh_path *mpath = NULL;
254         struct rhashtable_iter iter;
255 
256         ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
257         if (ret)
258                 return NULL;
259 
260         rhashtable_walk_start(&iter);
261 
262         while ((mpath = rhashtable_walk_next(&iter))) {
263                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
264                         continue;
265                 if (IS_ERR(mpath))
266                         break;
267                 if (i++ == idx)
268                         break;
269         }
270         rhashtable_walk_stop(&iter);
271         rhashtable_walk_exit(&iter);
272 
273         if (IS_ERR(mpath) || !mpath)
274                 return NULL;
275 
276         if (mpath_expired(mpath)) {
277                 spin_lock_bh(&mpath->state_lock);
278                 mpath->flags &= ~MESH_PATH_ACTIVE;
279                 spin_unlock_bh(&mpath->state_lock);
280         }
281         return mpath;
282 }
283 
284 /**
285  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
286  * @idx: index
287  * @sdata: local subif, or NULL for all entries
288  *
289  * Returns: pointer to the mesh path structure, or NULL if not found.
290  *
291  * Locking: must be called within a read rcu section.
292  */
293 struct mesh_path *
294 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
295 {
296         return __mesh_path_lookup_by_idx(sdata->u.mesh.mesh_paths, idx);
297 }
298 
299 /**
300  * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
301  * @idx: index
302  * @sdata: local subif, or NULL for all entries
303  *
304  * Returns: pointer to the proxy path structure, or NULL if not found.
305  *
306  * Locking: must be called within a read rcu section.
307  */
308 struct mesh_path *
309 mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
310 {
311         return __mesh_path_lookup_by_idx(sdata->u.mesh.mpp_paths, idx);
312 }
313 
314 /**
315  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
316  * @mpath: gate path to add to table
317  */
318 int mesh_path_add_gate(struct mesh_path *mpath)
319 {
320         struct mesh_table *tbl;
321         int err;
322 
323         rcu_read_lock();
324         tbl = mpath->sdata->u.mesh.mesh_paths;
325 
326         spin_lock_bh(&mpath->state_lock);
327         if (mpath->is_gate) {
328                 err = -EEXIST;
329                 spin_unlock_bh(&mpath->state_lock);
330                 goto err_rcu;
331         }
332         mpath->is_gate = true;
333         mpath->sdata->u.mesh.num_gates++;
334 
335         spin_lock(&tbl->gates_lock);
336         hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
337         spin_unlock(&tbl->gates_lock);
338 
339         spin_unlock_bh(&mpath->state_lock);
340 
341         mpath_dbg(mpath->sdata,
342                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
343                   mpath->dst, mpath->sdata->u.mesh.num_gates);
344         err = 0;
345 err_rcu:
346         rcu_read_unlock();
347         return err;
348 }
349 
350 /**
351  * mesh_gate_del - remove a mesh gate from the list of known gates
352  * @tbl: table which holds our list of known gates
353  * @mpath: gate mpath
354  */
355 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
356 {
357         lockdep_assert_held(&mpath->state_lock);
358         if (!mpath->is_gate)
359                 return;
360 
361         mpath->is_gate = false;
362         spin_lock_bh(&tbl->gates_lock);
363         hlist_del_rcu(&mpath->gate_list);
364         mpath->sdata->u.mesh.num_gates--;
365         spin_unlock_bh(&tbl->gates_lock);
366 
367         mpath_dbg(mpath->sdata,
368                   "Mesh path: Deleted gate: %pM. %d known gates\n",
369                   mpath->dst, mpath->sdata->u.mesh.num_gates);
370 }
371 
372 /**
373  * mesh_gate_num - number of gates known to this interface
374  * @sdata: subif data
375  */
376 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
377 {
378         return sdata->u.mesh.num_gates;
379 }
380 
381 static
382 struct mesh_path *mesh_path_new(struct ieee80211_sub_if_data *sdata,
383                                 const u8 *dst, gfp_t gfp_flags)
384 {
385         struct mesh_path *new_mpath;
386 
387         new_mpath = kzalloc(sizeof(struct mesh_path), gfp_flags);
388         if (!new_mpath)
389                 return NULL;
390 
391         memcpy(new_mpath->dst, dst, ETH_ALEN);
392         eth_broadcast_addr(new_mpath->rann_snd_addr);
393         new_mpath->is_root = false;
394         new_mpath->sdata = sdata;
395         new_mpath->flags = 0;
396         skb_queue_head_init(&new_mpath->frame_queue);
397         new_mpath->exp_time = jiffies;
398         spin_lock_init(&new_mpath->state_lock);
399         timer_setup(&new_mpath->timer, mesh_path_timer, 0);
400 
401         return new_mpath;
402 }
403 
404 /**
405  * mesh_path_add - allocate and add a new path to the mesh path table
406  * @dst: destination address of the path (ETH_ALEN length)
407  * @sdata: local subif
408  *
409  * Returns: 0 on success
410  *
411  * State: the initial state of the new path is set to 0
412  */
413 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
414                                 const u8 *dst)
415 {
416         struct mesh_table *tbl;
417         struct mesh_path *mpath, *new_mpath;
418         int ret;
419 
420         if (ether_addr_equal(dst, sdata->vif.addr))
421                 /* never add ourselves as neighbours */
422                 return ERR_PTR(-ENOTSUPP);
423 
424         if (is_multicast_ether_addr(dst))
425                 return ERR_PTR(-ENOTSUPP);
426 
427         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
428                 return ERR_PTR(-ENOSPC);
429 
430         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
431         if (!new_mpath)
432                 return ERR_PTR(-ENOMEM);
433 
434         tbl = sdata->u.mesh.mesh_paths;
435         do {
436                 ret = rhashtable_lookup_insert_fast(&tbl->rhead,
437                                                     &new_mpath->rhash,
438                                                     mesh_rht_params);
439 
440                 if (ret == -EEXIST)
441                         mpath = rhashtable_lookup_fast(&tbl->rhead,
442                                                        dst,
443                                                        mesh_rht_params);
444 
445         } while (unlikely(ret == -EEXIST && !mpath));
446 
447         if (ret && ret != -EEXIST)
448                 return ERR_PTR(ret);
449 
450         /* At this point either new_mpath was added, or we found a
451          * matching entry already in the table; in the latter case
452          * free the unnecessary new entry.
453          */
454         if (ret == -EEXIST) {
455                 kfree(new_mpath);
456                 new_mpath = mpath;
457         }
458         sdata->u.mesh.mesh_paths_generation++;
459         return new_mpath;
460 }
461 
462 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
463                  const u8 *dst, const u8 *mpp)
464 {
465         struct mesh_table *tbl;
466         struct mesh_path *new_mpath;
467         int ret;
468 
469         if (ether_addr_equal(dst, sdata->vif.addr))
470                 /* never add ourselves as neighbours */
471                 return -ENOTSUPP;
472 
473         if (is_multicast_ether_addr(dst))
474                 return -ENOTSUPP;
475 
476         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
477 
478         if (!new_mpath)
479                 return -ENOMEM;
480 
481         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
482         tbl = sdata->u.mesh.mpp_paths;
483         ret = rhashtable_lookup_insert_fast(&tbl->rhead,
484                                             &new_mpath->rhash,
485                                             mesh_rht_params);
486 
487         sdata->u.mesh.mpp_paths_generation++;
488         return ret;
489 }
490 
491 
492 /**
493  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
494  *
495  * @sta: broken peer link
496  *
497  * This function must be called from the rate control algorithm if enough
498  * delivery errors suggest that a peer link is no longer usable.
499  */
500 void mesh_plink_broken(struct sta_info *sta)
501 {
502         struct ieee80211_sub_if_data *sdata = sta->sdata;
503         struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
504         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
505         struct mesh_path *mpath;
506         struct rhashtable_iter iter;
507         int ret;
508 
509         ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
510         if (ret)
511                 return;
512 
513         rhashtable_walk_start(&iter);
514 
515         while ((mpath = rhashtable_walk_next(&iter))) {
516                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
517                         continue;
518                 if (IS_ERR(mpath))
519                         break;
520                 if (rcu_access_pointer(mpath->next_hop) == sta &&
521                     mpath->flags & MESH_PATH_ACTIVE &&
522                     !(mpath->flags & MESH_PATH_FIXED)) {
523                         spin_lock_bh(&mpath->state_lock);
524                         mpath->flags &= ~MESH_PATH_ACTIVE;
525                         ++mpath->sn;
526                         spin_unlock_bh(&mpath->state_lock);
527                         mesh_path_error_tx(sdata,
528                                 sdata->u.mesh.mshcfg.element_ttl,
529                                 mpath->dst, mpath->sn,
530                                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
531                 }
532         }
533         rhashtable_walk_stop(&iter);
534         rhashtable_walk_exit(&iter);
535 }
536 
537 static void mesh_path_free_rcu(struct mesh_table *tbl,
538                                struct mesh_path *mpath)
539 {
540         struct ieee80211_sub_if_data *sdata = mpath->sdata;
541 
542         spin_lock_bh(&mpath->state_lock);
543         mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
544         mesh_gate_del(tbl, mpath);
545         spin_unlock_bh(&mpath->state_lock);
546         del_timer_sync(&mpath->timer);
547         atomic_dec(&sdata->u.mesh.mpaths);
548         atomic_dec(&tbl->entries);
549         kfree_rcu(mpath, rcu);
550 }
551 
552 static void __mesh_path_del(struct mesh_table *tbl, struct mesh_path *mpath)
553 {
554         rhashtable_remove_fast(&tbl->rhead, &mpath->rhash, mesh_rht_params);
555         mesh_path_free_rcu(tbl, mpath);
556 }
557 
558 /**
559  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
560  *
561  * @sta: mesh peer to match
562  *
563  * RCU notes: this function is called when a mesh plink transitions from
564  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
565  * allows path creation. This will happen before the sta can be freed (because
566  * sta_info_destroy() calls this) so any reader in a rcu read block will be
567  * protected against the plink disappearing.
568  */
569 void mesh_path_flush_by_nexthop(struct sta_info *sta)
570 {
571         struct ieee80211_sub_if_data *sdata = sta->sdata;
572         struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
573         struct mesh_path *mpath;
574         struct rhashtable_iter iter;
575         int ret;
576 
577         ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
578         if (ret)
579                 return;
580 
581         rhashtable_walk_start(&iter);
582 
583         while ((mpath = rhashtable_walk_next(&iter))) {
584                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
585                         continue;
586                 if (IS_ERR(mpath))
587                         break;
588 
589                 if (rcu_access_pointer(mpath->next_hop) == sta)
590                         __mesh_path_del(tbl, mpath);
591         }
592 
593         rhashtable_walk_stop(&iter);
594         rhashtable_walk_exit(&iter);
595 }
596 
597 static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
598                                const u8 *proxy)
599 {
600         struct mesh_table *tbl = sdata->u.mesh.mpp_paths;
601         struct mesh_path *mpath;
602         struct rhashtable_iter iter;
603         int ret;
604 
605         ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
606         if (ret)
607                 return;
608 
609         rhashtable_walk_start(&iter);
610 
611         while ((mpath = rhashtable_walk_next(&iter))) {
612                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
613                         continue;
614                 if (IS_ERR(mpath))
615                         break;
616 
617                 if (ether_addr_equal(mpath->mpp, proxy))
618                         __mesh_path_del(tbl, mpath);
619         }
620 
621         rhashtable_walk_stop(&iter);
622         rhashtable_walk_exit(&iter);
623 }
624 
625 static void table_flush_by_iface(struct mesh_table *tbl)
626 {
627         struct mesh_path *mpath;
628         struct rhashtable_iter iter;
629         int ret;
630 
631         ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
632         if (ret)
633                 return;
634 
635         rhashtable_walk_start(&iter);
636 
637         while ((mpath = rhashtable_walk_next(&iter))) {
638                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
639                         continue;
640                 if (IS_ERR(mpath))
641                         break;
642                 __mesh_path_del(tbl, mpath);
643         }
644 
645         rhashtable_walk_stop(&iter);
646         rhashtable_walk_exit(&iter);
647 }
648 
649 /**
650  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
651  *
652  * This function deletes both mesh paths as well as mesh portal paths.
653  *
654  * @sdata: interface data to match
655  *
656  */
657 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
658 {
659         table_flush_by_iface(sdata->u.mesh.mesh_paths);
660         table_flush_by_iface(sdata->u.mesh.mpp_paths);
661 }
662 
663 /**
664  * table_path_del - delete a path from the mesh or mpp table
665  *
666  * @tbl: mesh or mpp path table
667  * @sdata: local subif
668  * @addr: dst address (ETH_ALEN length)
669  *
670  * Returns: 0 if successful
671  */
672 static int table_path_del(struct mesh_table *tbl,
673                           struct ieee80211_sub_if_data *sdata,
674                           const u8 *addr)
675 {
676         struct mesh_path *mpath;
677 
678         rcu_read_lock();
679         mpath = rhashtable_lookup_fast(&tbl->rhead, addr, mesh_rht_params);
680         if (!mpath) {
681                 rcu_read_unlock();
682                 return -ENXIO;
683         }
684 
685         __mesh_path_del(tbl, mpath);
686         rcu_read_unlock();
687         return 0;
688 }
689 
690 
691 /**
692  * mesh_path_del - delete a mesh path from the table
693  *
694  * @addr: dst address (ETH_ALEN length)
695  * @sdata: local subif
696  *
697  * Returns: 0 if successful
698  */
699 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
700 {
701         int err;
702 
703         /* flush relevant mpp entries first */
704         mpp_flush_by_proxy(sdata, addr);
705 
706         err = table_path_del(sdata->u.mesh.mesh_paths, sdata, addr);
707         sdata->u.mesh.mesh_paths_generation++;
708         return err;
709 }
710 
711 /**
712  * mesh_path_tx_pending - sends pending frames in a mesh path queue
713  *
714  * @mpath: mesh path to activate
715  *
716  * Locking: the state_lock of the mpath structure must NOT be held when calling
717  * this function.
718  */
719 void mesh_path_tx_pending(struct mesh_path *mpath)
720 {
721         if (mpath->flags & MESH_PATH_ACTIVE)
722                 ieee80211_add_pending_skbs(mpath->sdata->local,
723                                 &mpath->frame_queue);
724 }
725 
726 /**
727  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
728  *
729  * @mpath: mesh path whose queue will be emptied
730  *
731  * If there is only one gate, the frames are transferred from the failed mpath
732  * queue to that gate's queue.  If there are more than one gates, the frames
733  * are copied from each gate to the next.  After frames are copied, the
734  * mpath queues are emptied onto the transmission queue.
735  */
736 int mesh_path_send_to_gates(struct mesh_path *mpath)
737 {
738         struct ieee80211_sub_if_data *sdata = mpath->sdata;
739         struct mesh_table *tbl;
740         struct mesh_path *from_mpath = mpath;
741         struct mesh_path *gate;
742         bool copy = false;
743 
744         tbl = sdata->u.mesh.mesh_paths;
745 
746         rcu_read_lock();
747         hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
748                 if (gate->flags & MESH_PATH_ACTIVE) {
749                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->dst);
750                         mesh_path_move_to_queue(gate, from_mpath, copy);
751                         from_mpath = gate;
752                         copy = true;
753                 } else {
754                         mpath_dbg(sdata,
755                                   "Not forwarding to %pM (flags %#x)\n",
756                                   gate->dst, gate->flags);
757                 }
758         }
759 
760         hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
761                 mpath_dbg(sdata, "Sending to %pM\n", gate->dst);
762                 mesh_path_tx_pending(gate);
763         }
764         rcu_read_unlock();
765 
766         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
767 }
768 
769 /**
770  * mesh_path_discard_frame - discard a frame whose path could not be resolved
771  *
772  * @skb: frame to discard
773  * @sdata: network subif the frame was to be sent through
774  *
775  * Locking: the function must me called within a rcu_read_lock region
776  */
777 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
778                              struct sk_buff *skb)
779 {
780         kfree_skb(skb);
781         sdata->u.mesh.mshstats.dropped_frames_no_route++;
782 }
783 
784 /**
785  * mesh_path_flush_pending - free the pending queue of a mesh path
786  *
787  * @mpath: mesh path whose queue has to be freed
788  *
789  * Locking: the function must me called within a rcu_read_lock region
790  */
791 void mesh_path_flush_pending(struct mesh_path *mpath)
792 {
793         struct sk_buff *skb;
794 
795         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
796                 mesh_path_discard_frame(mpath->sdata, skb);
797 }
798 
799 /**
800  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
801  *
802  * @mpath: the mesh path to modify
803  * @next_hop: the next hop to force
804  *
805  * Locking: this function must be called holding mpath->state_lock
806  */
807 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
808 {
809         spin_lock_bh(&mpath->state_lock);
810         mesh_path_assign_nexthop(mpath, next_hop);
811         mpath->sn = 0xffff;
812         mpath->metric = 0;
813         mpath->hop_count = 0;
814         mpath->exp_time = 0;
815         mpath->flags = MESH_PATH_FIXED | MESH_PATH_SN_VALID;
816         mesh_path_activate(mpath);
817         spin_unlock_bh(&mpath->state_lock);
818         ewma_mesh_fail_avg_init(&next_hop->mesh->fail_avg);
819         /* init it at a low value - 0 start is tricky */
820         ewma_mesh_fail_avg_add(&next_hop->mesh->fail_avg, 1);
821         mesh_path_tx_pending(mpath);
822 }
823 
824 int mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
825 {
826         struct mesh_table *tbl_path, *tbl_mpp;
827         int ret;
828 
829         tbl_path = mesh_table_alloc();
830         if (!tbl_path)
831                 return -ENOMEM;
832 
833         tbl_mpp = mesh_table_alloc();
834         if (!tbl_mpp) {
835                 ret = -ENOMEM;
836                 goto free_path;
837         }
838 
839         rhashtable_init(&tbl_path->rhead, &mesh_rht_params);
840         rhashtable_init(&tbl_mpp->rhead, &mesh_rht_params);
841 
842         sdata->u.mesh.mesh_paths = tbl_path;
843         sdata->u.mesh.mpp_paths = tbl_mpp;
844 
845         return 0;
846 
847 free_path:
848         mesh_table_free(tbl_path);
849         return ret;
850 }
851 
852 static
853 void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
854                           struct mesh_table *tbl)
855 {
856         struct mesh_path *mpath;
857         struct rhashtable_iter iter;
858         int ret;
859 
860         ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_KERNEL);
861         if (ret)
862                 return;
863 
864         rhashtable_walk_start(&iter);
865 
866         while ((mpath = rhashtable_walk_next(&iter))) {
867                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
868                         continue;
869                 if (IS_ERR(mpath))
870                         break;
871                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
872                     (!(mpath->flags & MESH_PATH_FIXED)) &&
873                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
874                         __mesh_path_del(tbl, mpath);
875         }
876 
877         rhashtable_walk_stop(&iter);
878         rhashtable_walk_exit(&iter);
879 }
880 
881 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
882 {
883         mesh_path_tbl_expire(sdata, sdata->u.mesh.mesh_paths);
884         mesh_path_tbl_expire(sdata, sdata->u.mesh.mpp_paths);
885 }
886 
887 void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
888 {
889         mesh_table_free(sdata->u.mesh.mesh_paths);
890         mesh_table_free(sdata->u.mesh.mpp_paths);
891 }
892 

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