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TOMOYO Linux Cross Reference
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         ret = rhashtable_walk_start(&iter);
261         if (ret && ret != -EAGAIN)
262                 goto err;
263 
264         while ((mpath = rhashtable_walk_next(&iter))) {
265                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
266                         continue;
267                 if (IS_ERR(mpath))
268                         break;
269                 if (i++ == idx)
270                         break;
271         }
272 err:
273         rhashtable_walk_stop(&iter);
274         rhashtable_walk_exit(&iter);
275 
276         if (IS_ERR(mpath) || !mpath)
277                 return NULL;
278 
279         if (mpath_expired(mpath)) {
280                 spin_lock_bh(&mpath->state_lock);
281                 mpath->flags &= ~MESH_PATH_ACTIVE;
282                 spin_unlock_bh(&mpath->state_lock);
283         }
284         return mpath;
285 }
286 
287 /**
288  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
289  * @idx: index
290  * @sdata: local subif, or NULL for all entries
291  *
292  * Returns: pointer to the mesh path structure, or NULL if not found.
293  *
294  * Locking: must be called within a read rcu section.
295  */
296 struct mesh_path *
297 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
298 {
299         return __mesh_path_lookup_by_idx(sdata->u.mesh.mesh_paths, idx);
300 }
301 
302 /**
303  * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
304  * @idx: index
305  * @sdata: local subif, or NULL for all entries
306  *
307  * Returns: pointer to the proxy path structure, or NULL if not found.
308  *
309  * Locking: must be called within a read rcu section.
310  */
311 struct mesh_path *
312 mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
313 {
314         return __mesh_path_lookup_by_idx(sdata->u.mesh.mpp_paths, idx);
315 }
316 
317 /**
318  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
319  * @mpath: gate path to add to table
320  */
321 int mesh_path_add_gate(struct mesh_path *mpath)
322 {
323         struct mesh_table *tbl;
324         int err;
325 
326         rcu_read_lock();
327         tbl = mpath->sdata->u.mesh.mesh_paths;
328 
329         spin_lock_bh(&mpath->state_lock);
330         if (mpath->is_gate) {
331                 err = -EEXIST;
332                 spin_unlock_bh(&mpath->state_lock);
333                 goto err_rcu;
334         }
335         mpath->is_gate = true;
336         mpath->sdata->u.mesh.num_gates++;
337 
338         spin_lock(&tbl->gates_lock);
339         hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
340         spin_unlock(&tbl->gates_lock);
341 
342         spin_unlock_bh(&mpath->state_lock);
343 
344         mpath_dbg(mpath->sdata,
345                   "Mesh path: Recorded new gate: %pM. %d known gates\n",
346                   mpath->dst, mpath->sdata->u.mesh.num_gates);
347         err = 0;
348 err_rcu:
349         rcu_read_unlock();
350         return err;
351 }
352 
353 /**
354  * mesh_gate_del - remove a mesh gate from the list of known gates
355  * @tbl: table which holds our list of known gates
356  * @mpath: gate mpath
357  */
358 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
359 {
360         lockdep_assert_held(&mpath->state_lock);
361         if (!mpath->is_gate)
362                 return;
363 
364         mpath->is_gate = false;
365         spin_lock_bh(&tbl->gates_lock);
366         hlist_del_rcu(&mpath->gate_list);
367         mpath->sdata->u.mesh.num_gates--;
368         spin_unlock_bh(&tbl->gates_lock);
369 
370         mpath_dbg(mpath->sdata,
371                   "Mesh path: Deleted gate: %pM. %d known gates\n",
372                   mpath->dst, mpath->sdata->u.mesh.num_gates);
373 }
374 
375 /**
376  * mesh_gate_num - number of gates known to this interface
377  * @sdata: subif data
378  */
379 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
380 {
381         return sdata->u.mesh.num_gates;
382 }
383 
384 static
385 struct mesh_path *mesh_path_new(struct ieee80211_sub_if_data *sdata,
386                                 const u8 *dst, gfp_t gfp_flags)
387 {
388         struct mesh_path *new_mpath;
389 
390         new_mpath = kzalloc(sizeof(struct mesh_path), gfp_flags);
391         if (!new_mpath)
392                 return NULL;
393 
394         memcpy(new_mpath->dst, dst, ETH_ALEN);
395         eth_broadcast_addr(new_mpath->rann_snd_addr);
396         new_mpath->is_root = false;
397         new_mpath->sdata = sdata;
398         new_mpath->flags = 0;
399         skb_queue_head_init(&new_mpath->frame_queue);
400         new_mpath->timer.data = (unsigned long) new_mpath;
401         new_mpath->timer.function = mesh_path_timer;
402         new_mpath->exp_time = jiffies;
403         spin_lock_init(&new_mpath->state_lock);
404         init_timer(&new_mpath->timer);
405 
406         return new_mpath;
407 }
408 
409 /**
410  * mesh_path_add - allocate and add a new path to the mesh path table
411  * @dst: destination address of the path (ETH_ALEN length)
412  * @sdata: local subif
413  *
414  * Returns: 0 on success
415  *
416  * State: the initial state of the new path is set to 0
417  */
418 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
419                                 const u8 *dst)
420 {
421         struct mesh_table *tbl;
422         struct mesh_path *mpath, *new_mpath;
423         int ret;
424 
425         if (ether_addr_equal(dst, sdata->vif.addr))
426                 /* never add ourselves as neighbours */
427                 return ERR_PTR(-ENOTSUPP);
428 
429         if (is_multicast_ether_addr(dst))
430                 return ERR_PTR(-ENOTSUPP);
431 
432         if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
433                 return ERR_PTR(-ENOSPC);
434 
435         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
436         if (!new_mpath)
437                 return ERR_PTR(-ENOMEM);
438 
439         tbl = sdata->u.mesh.mesh_paths;
440         do {
441                 ret = rhashtable_lookup_insert_fast(&tbl->rhead,
442                                                     &new_mpath->rhash,
443                                                     mesh_rht_params);
444 
445                 if (ret == -EEXIST)
446                         mpath = rhashtable_lookup_fast(&tbl->rhead,
447                                                        dst,
448                                                        mesh_rht_params);
449 
450         } while (unlikely(ret == -EEXIST && !mpath));
451 
452         if (ret && ret != -EEXIST)
453                 return ERR_PTR(ret);
454 
455         /* At this point either new_mpath was added, or we found a
456          * matching entry already in the table; in the latter case
457          * free the unnecessary new entry.
458          */
459         if (ret == -EEXIST) {
460                 kfree(new_mpath);
461                 new_mpath = mpath;
462         }
463         sdata->u.mesh.mesh_paths_generation++;
464         return new_mpath;
465 }
466 
467 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
468                  const u8 *dst, const u8 *mpp)
469 {
470         struct mesh_table *tbl;
471         struct mesh_path *new_mpath;
472         int ret;
473 
474         if (ether_addr_equal(dst, sdata->vif.addr))
475                 /* never add ourselves as neighbours */
476                 return -ENOTSUPP;
477 
478         if (is_multicast_ether_addr(dst))
479                 return -ENOTSUPP;
480 
481         new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
482 
483         if (!new_mpath)
484                 return -ENOMEM;
485 
486         memcpy(new_mpath->mpp, mpp, ETH_ALEN);
487         tbl = sdata->u.mesh.mpp_paths;
488         ret = rhashtable_lookup_insert_fast(&tbl->rhead,
489                                             &new_mpath->rhash,
490                                             mesh_rht_params);
491 
492         sdata->u.mesh.mpp_paths_generation++;
493         return ret;
494 }
495 
496 
497 /**
498  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
499  *
500  * @sta: broken peer link
501  *
502  * This function must be called from the rate control algorithm if enough
503  * delivery errors suggest that a peer link is no longer usable.
504  */
505 void mesh_plink_broken(struct sta_info *sta)
506 {
507         struct ieee80211_sub_if_data *sdata = sta->sdata;
508         struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
509         static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
510         struct mesh_path *mpath;
511         struct rhashtable_iter iter;
512         int ret;
513 
514         ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
515         if (ret)
516                 return;
517 
518         ret = rhashtable_walk_start(&iter);
519         if (ret && ret != -EAGAIN)
520                 goto out;
521 
522         while ((mpath = rhashtable_walk_next(&iter))) {
523                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
524                         continue;
525                 if (IS_ERR(mpath))
526                         break;
527                 if (rcu_access_pointer(mpath->next_hop) == sta &&
528                     mpath->flags & MESH_PATH_ACTIVE &&
529                     !(mpath->flags & MESH_PATH_FIXED)) {
530                         spin_lock_bh(&mpath->state_lock);
531                         mpath->flags &= ~MESH_PATH_ACTIVE;
532                         ++mpath->sn;
533                         spin_unlock_bh(&mpath->state_lock);
534                         mesh_path_error_tx(sdata,
535                                 sdata->u.mesh.mshcfg.element_ttl,
536                                 mpath->dst, mpath->sn,
537                                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
538                 }
539         }
540 out:
541         rhashtable_walk_stop(&iter);
542         rhashtable_walk_exit(&iter);
543 }
544 
545 static void mesh_path_free_rcu(struct mesh_table *tbl,
546                                struct mesh_path *mpath)
547 {
548         struct ieee80211_sub_if_data *sdata = mpath->sdata;
549 
550         spin_lock_bh(&mpath->state_lock);
551         mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
552         mesh_gate_del(tbl, mpath);
553         spin_unlock_bh(&mpath->state_lock);
554         del_timer_sync(&mpath->timer);
555         atomic_dec(&sdata->u.mesh.mpaths);
556         atomic_dec(&tbl->entries);
557         kfree_rcu(mpath, rcu);
558 }
559 
560 static void __mesh_path_del(struct mesh_table *tbl, struct mesh_path *mpath)
561 {
562         rhashtable_remove_fast(&tbl->rhead, &mpath->rhash, mesh_rht_params);
563         mesh_path_free_rcu(tbl, mpath);
564 }
565 
566 /**
567  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
568  *
569  * @sta: mesh peer to match
570  *
571  * RCU notes: this function is called when a mesh plink transitions from
572  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
573  * allows path creation. This will happen before the sta can be freed (because
574  * sta_info_destroy() calls this) so any reader in a rcu read block will be
575  * protected against the plink disappearing.
576  */
577 void mesh_path_flush_by_nexthop(struct sta_info *sta)
578 {
579         struct ieee80211_sub_if_data *sdata = sta->sdata;
580         struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
581         struct mesh_path *mpath;
582         struct rhashtable_iter iter;
583         int ret;
584 
585         ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
586         if (ret)
587                 return;
588 
589         ret = rhashtable_walk_start(&iter);
590         if (ret && ret != -EAGAIN)
591                 goto out;
592 
593         while ((mpath = rhashtable_walk_next(&iter))) {
594                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
595                         continue;
596                 if (IS_ERR(mpath))
597                         break;
598 
599                 if (rcu_access_pointer(mpath->next_hop) == sta)
600                         __mesh_path_del(tbl, mpath);
601         }
602 out:
603         rhashtable_walk_stop(&iter);
604         rhashtable_walk_exit(&iter);
605 }
606 
607 static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
608                                const u8 *proxy)
609 {
610         struct mesh_table *tbl = sdata->u.mesh.mpp_paths;
611         struct mesh_path *mpath;
612         struct rhashtable_iter iter;
613         int ret;
614 
615         ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
616         if (ret)
617                 return;
618 
619         ret = rhashtable_walk_start(&iter);
620         if (ret && ret != -EAGAIN)
621                 goto out;
622 
623         while ((mpath = rhashtable_walk_next(&iter))) {
624                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
625                         continue;
626                 if (IS_ERR(mpath))
627                         break;
628 
629                 if (ether_addr_equal(mpath->mpp, proxy))
630                         __mesh_path_del(tbl, mpath);
631         }
632 out:
633         rhashtable_walk_stop(&iter);
634         rhashtable_walk_exit(&iter);
635 }
636 
637 static void table_flush_by_iface(struct mesh_table *tbl)
638 {
639         struct mesh_path *mpath;
640         struct rhashtable_iter iter;
641         int ret;
642 
643         ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
644         if (ret)
645                 return;
646 
647         ret = rhashtable_walk_start(&iter);
648         if (ret && ret != -EAGAIN)
649                 goto out;
650 
651         while ((mpath = rhashtable_walk_next(&iter))) {
652                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
653                         continue;
654                 if (IS_ERR(mpath))
655                         break;
656                 __mesh_path_del(tbl, mpath);
657         }
658 out:
659         rhashtable_walk_stop(&iter);
660         rhashtable_walk_exit(&iter);
661 }
662 
663 /**
664  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
665  *
666  * This function deletes both mesh paths as well as mesh portal paths.
667  *
668  * @sdata: interface data to match
669  *
670  */
671 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
672 {
673         table_flush_by_iface(sdata->u.mesh.mesh_paths);
674         table_flush_by_iface(sdata->u.mesh.mpp_paths);
675 }
676 
677 /**
678  * table_path_del - delete a path from the mesh or mpp table
679  *
680  * @tbl: mesh or mpp path table
681  * @sdata: local subif
682  * @addr: dst address (ETH_ALEN length)
683  *
684  * Returns: 0 if successful
685  */
686 static int table_path_del(struct mesh_table *tbl,
687                           struct ieee80211_sub_if_data *sdata,
688                           const u8 *addr)
689 {
690         struct mesh_path *mpath;
691 
692         rcu_read_lock();
693         mpath = rhashtable_lookup_fast(&tbl->rhead, addr, mesh_rht_params);
694         if (!mpath) {
695                 rcu_read_unlock();
696                 return -ENXIO;
697         }
698 
699         __mesh_path_del(tbl, mpath);
700         rcu_read_unlock();
701         return 0;
702 }
703 
704 
705 /**
706  * mesh_path_del - delete a mesh path from the table
707  *
708  * @addr: dst address (ETH_ALEN length)
709  * @sdata: local subif
710  *
711  * Returns: 0 if successful
712  */
713 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
714 {
715         int err;
716 
717         /* flush relevant mpp entries first */
718         mpp_flush_by_proxy(sdata, addr);
719 
720         err = table_path_del(sdata->u.mesh.mesh_paths, sdata, addr);
721         sdata->u.mesh.mesh_paths_generation++;
722         return err;
723 }
724 
725 /**
726  * mesh_path_tx_pending - sends pending frames in a mesh path queue
727  *
728  * @mpath: mesh path to activate
729  *
730  * Locking: the state_lock of the mpath structure must NOT be held when calling
731  * this function.
732  */
733 void mesh_path_tx_pending(struct mesh_path *mpath)
734 {
735         if (mpath->flags & MESH_PATH_ACTIVE)
736                 ieee80211_add_pending_skbs(mpath->sdata->local,
737                                 &mpath->frame_queue);
738 }
739 
740 /**
741  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
742  *
743  * @mpath: mesh path whose queue will be emptied
744  *
745  * If there is only one gate, the frames are transferred from the failed mpath
746  * queue to that gate's queue.  If there are more than one gates, the frames
747  * are copied from each gate to the next.  After frames are copied, the
748  * mpath queues are emptied onto the transmission queue.
749  */
750 int mesh_path_send_to_gates(struct mesh_path *mpath)
751 {
752         struct ieee80211_sub_if_data *sdata = mpath->sdata;
753         struct mesh_table *tbl;
754         struct mesh_path *from_mpath = mpath;
755         struct mesh_path *gate;
756         bool copy = false;
757 
758         tbl = sdata->u.mesh.mesh_paths;
759 
760         rcu_read_lock();
761         hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
762                 if (gate->flags & MESH_PATH_ACTIVE) {
763                         mpath_dbg(sdata, "Forwarding to %pM\n", gate->dst);
764                         mesh_path_move_to_queue(gate, from_mpath, copy);
765                         from_mpath = gate;
766                         copy = true;
767                 } else {
768                         mpath_dbg(sdata,
769                                   "Not forwarding to %pM (flags %#x)\n",
770                                   gate->dst, gate->flags);
771                 }
772         }
773 
774         hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
775                 mpath_dbg(sdata, "Sending to %pM\n", gate->dst);
776                 mesh_path_tx_pending(gate);
777         }
778         rcu_read_unlock();
779 
780         return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
781 }
782 
783 /**
784  * mesh_path_discard_frame - discard a frame whose path could not be resolved
785  *
786  * @skb: frame to discard
787  * @sdata: network subif the frame was to be sent through
788  *
789  * Locking: the function must me called within a rcu_read_lock region
790  */
791 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
792                              struct sk_buff *skb)
793 {
794         kfree_skb(skb);
795         sdata->u.mesh.mshstats.dropped_frames_no_route++;
796 }
797 
798 /**
799  * mesh_path_flush_pending - free the pending queue of a mesh path
800  *
801  * @mpath: mesh path whose queue has to be freed
802  *
803  * Locking: the function must me called within a rcu_read_lock region
804  */
805 void mesh_path_flush_pending(struct mesh_path *mpath)
806 {
807         struct sk_buff *skb;
808 
809         while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
810                 mesh_path_discard_frame(mpath->sdata, skb);
811 }
812 
813 /**
814  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
815  *
816  * @mpath: the mesh path to modify
817  * @next_hop: the next hop to force
818  *
819  * Locking: this function must be called holding mpath->state_lock
820  */
821 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
822 {
823         spin_lock_bh(&mpath->state_lock);
824         mesh_path_assign_nexthop(mpath, next_hop);
825         mpath->sn = 0xffff;
826         mpath->metric = 0;
827         mpath->hop_count = 0;
828         mpath->exp_time = 0;
829         mpath->flags = MESH_PATH_FIXED | MESH_PATH_SN_VALID;
830         mesh_path_activate(mpath);
831         spin_unlock_bh(&mpath->state_lock);
832         mesh_path_tx_pending(mpath);
833 }
834 
835 int mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
836 {
837         struct mesh_table *tbl_path, *tbl_mpp;
838         int ret;
839 
840         tbl_path = mesh_table_alloc();
841         if (!tbl_path)
842                 return -ENOMEM;
843 
844         tbl_mpp = mesh_table_alloc();
845         if (!tbl_mpp) {
846                 ret = -ENOMEM;
847                 goto free_path;
848         }
849 
850         rhashtable_init(&tbl_path->rhead, &mesh_rht_params);
851         rhashtable_init(&tbl_mpp->rhead, &mesh_rht_params);
852 
853         sdata->u.mesh.mesh_paths = tbl_path;
854         sdata->u.mesh.mpp_paths = tbl_mpp;
855 
856         return 0;
857 
858 free_path:
859         mesh_table_free(tbl_path);
860         return ret;
861 }
862 
863 static
864 void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
865                           struct mesh_table *tbl)
866 {
867         struct mesh_path *mpath;
868         struct rhashtable_iter iter;
869         int ret;
870 
871         ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_KERNEL);
872         if (ret)
873                 return;
874 
875         ret = rhashtable_walk_start(&iter);
876         if (ret && ret != -EAGAIN)
877                 goto out;
878 
879         while ((mpath = rhashtable_walk_next(&iter))) {
880                 if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
881                         continue;
882                 if (IS_ERR(mpath))
883                         break;
884                 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
885                     (!(mpath->flags & MESH_PATH_FIXED)) &&
886                      time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
887                         __mesh_path_del(tbl, mpath);
888         }
889 out:
890         rhashtable_walk_stop(&iter);
891         rhashtable_walk_exit(&iter);
892 }
893 
894 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
895 {
896         mesh_path_tbl_expire(sdata, sdata->u.mesh.mesh_paths);
897         mesh_path_tbl_expire(sdata, sdata->u.mesh.mpp_paths);
898 }
899 
900 void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
901 {
902         mesh_table_free(sdata->u.mesh.mesh_paths);
903         mesh_table_free(sdata->u.mesh.mpp_paths);
904 }
905 

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