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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
21static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);
22
23static 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
29static 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
38static 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
45static 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
53static 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
68static 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 */
84void 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
103static 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 */
161static 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
213static 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 */
237struct mesh_path *
238mesh_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
243struct mesh_path *
244mpp_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
249static 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 }
272err:
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 */
296struct mesh_path *
297mesh_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 */
311struct mesh_path *
312mpp_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 */
321int 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;
348err_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 */
358static 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 */
379int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
380{
381 return sdata->u.mesh.num_gates;
382}
383
384static
385struct 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 */
418struct 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
467int 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 */
505void 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 }
540out:
541 rhashtable_walk_stop(&iter);
542 rhashtable_walk_exit(&iter);
543}
544
545static 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
560static 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 */
577void 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 }
602out:
603 rhashtable_walk_stop(&iter);
604 rhashtable_walk_exit(&iter);
605}
606
607static 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 }
632out:
633 rhashtable_walk_stop(&iter);
634 rhashtable_walk_exit(&iter);
635}
636
637static 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 }
658out:
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 */
671void 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 */
686static 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 */
713int 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 */
733void 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 */
750int 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 */
791void 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 */
805void 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 */
821void 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
835int 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
858free_path:
859 mesh_table_free(tbl_path);
860 return ret;
861}
862
863static
864void 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 }
889out:
890 rhashtable_walk_stop(&iter);
891 rhashtable_walk_exit(&iter);
892}
893
894void 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
900void 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}
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 "ieee80211_i.h"
18#include "mesh.h"
19
20/* There will be initially 2^INIT_PATHS_SIZE_ORDER buckets */
21#define INIT_PATHS_SIZE_ORDER 2
22
23/* Keep the mean chain length below this constant */
24#define MEAN_CHAIN_LEN 2
25
26#define MPATH_EXPIRED(mpath) ((mpath->flags & MESH_PATH_ACTIVE) && \
27 time_after(jiffies, mpath->exp_time) && \
28 !(mpath->flags & MESH_PATH_FIXED))
29
30struct mpath_node {
31 struct hlist_node list;
32 struct rcu_head rcu;
33 /* This indirection allows two different tables to point to the same
34 * mesh_path structure, useful when resizing
35 */
36 struct mesh_path *mpath;
37};
38
39static struct mesh_table __rcu *mesh_paths;
40static struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
41
42int mesh_paths_generation;
43
44/* This lock will have the grow table function as writer and add / delete nodes
45 * as readers. When reading the table (i.e. doing lookups) we are well protected
46 * by RCU
47 */
48static DEFINE_RWLOCK(pathtbl_resize_lock);
49
50
51static inline struct mesh_table *resize_dereference_mesh_paths(void)
52{
53 return rcu_dereference_protected(mesh_paths,
54 lockdep_is_held(&pathtbl_resize_lock));
55}
56
57static inline struct mesh_table *resize_dereference_mpp_paths(void)
58{
59 return rcu_dereference_protected(mpp_paths,
60 lockdep_is_held(&pathtbl_resize_lock));
61}
62
63/*
64 * CAREFUL -- "tbl" must not be an expression,
65 * in particular not an rcu_dereference(), since
66 * it's used twice. So it is illegal to do
67 * for_each_mesh_entry(rcu_dereference(...), ...)
68 */
69#define for_each_mesh_entry(tbl, p, node, i) \
70 for (i = 0; i <= tbl->hash_mask; i++) \
71 hlist_for_each_entry_rcu(node, p, &tbl->hash_buckets[i], list)
72
73
74static struct mesh_table *mesh_table_alloc(int size_order)
75{
76 int i;
77 struct mesh_table *newtbl;
78
79 newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
80 if (!newtbl)
81 return NULL;
82
83 newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
84 (1 << size_order), GFP_ATOMIC);
85
86 if (!newtbl->hash_buckets) {
87 kfree(newtbl);
88 return NULL;
89 }
90
91 newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
92 (1 << size_order), GFP_ATOMIC);
93 if (!newtbl->hashwlock) {
94 kfree(newtbl->hash_buckets);
95 kfree(newtbl);
96 return NULL;
97 }
98
99 newtbl->size_order = size_order;
100 newtbl->hash_mask = (1 << size_order) - 1;
101 atomic_set(&newtbl->entries, 0);
102 get_random_bytes(&newtbl->hash_rnd,
103 sizeof(newtbl->hash_rnd));
104 for (i = 0; i <= newtbl->hash_mask; i++)
105 spin_lock_init(&newtbl->hashwlock[i]);
106
107 return newtbl;
108}
109
110static void __mesh_table_free(struct mesh_table *tbl)
111{
112 kfree(tbl->hash_buckets);
113 kfree(tbl->hashwlock);
114 kfree(tbl);
115}
116
117static void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
118{
119 struct hlist_head *mesh_hash;
120 struct hlist_node *p, *q;
121 int i;
122
123 mesh_hash = tbl->hash_buckets;
124 for (i = 0; i <= tbl->hash_mask; i++) {
125 spin_lock_bh(&tbl->hashwlock[i]);
126 hlist_for_each_safe(p, q, &mesh_hash[i]) {
127 tbl->free_node(p, free_leafs);
128 atomic_dec(&tbl->entries);
129 }
130 spin_unlock_bh(&tbl->hashwlock[i]);
131 }
132 __mesh_table_free(tbl);
133}
134
135static int mesh_table_grow(struct mesh_table *oldtbl,
136 struct mesh_table *newtbl)
137{
138 struct hlist_head *oldhash;
139 struct hlist_node *p, *q;
140 int i;
141
142 if (atomic_read(&oldtbl->entries)
143 < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
144 return -EAGAIN;
145
146 newtbl->free_node = oldtbl->free_node;
147 newtbl->mean_chain_len = oldtbl->mean_chain_len;
148 newtbl->copy_node = oldtbl->copy_node;
149 atomic_set(&newtbl->entries, atomic_read(&oldtbl->entries));
150
151 oldhash = oldtbl->hash_buckets;
152 for (i = 0; i <= oldtbl->hash_mask; i++)
153 hlist_for_each(p, &oldhash[i])
154 if (oldtbl->copy_node(p, newtbl) < 0)
155 goto errcopy;
156
157 return 0;
158
159errcopy:
160 for (i = 0; i <= newtbl->hash_mask; i++) {
161 hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
162 oldtbl->free_node(p, 0);
163 }
164 return -ENOMEM;
165}
166
167static u32 mesh_table_hash(u8 *addr, struct ieee80211_sub_if_data *sdata,
168 struct mesh_table *tbl)
169{
170 /* Use last four bytes of hw addr and interface index as hash index */
171 return jhash_2words(*(u32 *)(addr+2), sdata->dev->ifindex, tbl->hash_rnd)
172 & tbl->hash_mask;
173}
174
175
176/**
177 *
178 * mesh_path_assign_nexthop - update mesh path next hop
179 *
180 * @mpath: mesh path to update
181 * @sta: next hop to assign
182 *
183 * Locking: mpath->state_lock must be held when calling this function
184 */
185void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
186{
187 struct sk_buff *skb;
188 struct ieee80211_hdr *hdr;
189 struct sk_buff_head tmpq;
190 unsigned long flags;
191
192 rcu_assign_pointer(mpath->next_hop, sta);
193
194 __skb_queue_head_init(&tmpq);
195
196 spin_lock_irqsave(&mpath->frame_queue.lock, flags);
197
198 while ((skb = __skb_dequeue(&mpath->frame_queue)) != NULL) {
199 hdr = (struct ieee80211_hdr *) skb->data;
200 memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
201 __skb_queue_tail(&tmpq, skb);
202 }
203
204 skb_queue_splice(&tmpq, &mpath->frame_queue);
205 spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
206}
207
208
209/**
210 * mesh_path_lookup - look up a path in the mesh path table
211 * @dst: hardware address (ETH_ALEN length) of destination
212 * @sdata: local subif
213 *
214 * Returns: pointer to the mesh path structure, or NULL if not found
215 *
216 * Locking: must be called within a read rcu section.
217 */
218struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
219{
220 struct mesh_path *mpath;
221 struct hlist_node *n;
222 struct hlist_head *bucket;
223 struct mesh_table *tbl;
224 struct mpath_node *node;
225
226 tbl = rcu_dereference(mesh_paths);
227
228 bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
229 hlist_for_each_entry_rcu(node, n, bucket, list) {
230 mpath = node->mpath;
231 if (mpath->sdata == sdata &&
232 memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
233 if (MPATH_EXPIRED(mpath)) {
234 spin_lock_bh(&mpath->state_lock);
235 if (MPATH_EXPIRED(mpath))
236 mpath->flags &= ~MESH_PATH_ACTIVE;
237 spin_unlock_bh(&mpath->state_lock);
238 }
239 return mpath;
240 }
241 }
242 return NULL;
243}
244
245struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
246{
247 struct mesh_path *mpath;
248 struct hlist_node *n;
249 struct hlist_head *bucket;
250 struct mesh_table *tbl;
251 struct mpath_node *node;
252
253 tbl = rcu_dereference(mpp_paths);
254
255 bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
256 hlist_for_each_entry_rcu(node, n, bucket, list) {
257 mpath = node->mpath;
258 if (mpath->sdata == sdata &&
259 memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
260 if (MPATH_EXPIRED(mpath)) {
261 spin_lock_bh(&mpath->state_lock);
262 if (MPATH_EXPIRED(mpath))
263 mpath->flags &= ~MESH_PATH_ACTIVE;
264 spin_unlock_bh(&mpath->state_lock);
265 }
266 return mpath;
267 }
268 }
269 return NULL;
270}
271
272
273/**
274 * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
275 * @idx: index
276 * @sdata: local subif, or NULL for all entries
277 *
278 * Returns: pointer to the mesh path structure, or NULL if not found.
279 *
280 * Locking: must be called within a read rcu section.
281 */
282struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data *sdata)
283{
284 struct mesh_table *tbl = rcu_dereference(mesh_paths);
285 struct mpath_node *node;
286 struct hlist_node *p;
287 int i;
288 int j = 0;
289
290 for_each_mesh_entry(tbl, p, node, i) {
291 if (sdata && node->mpath->sdata != sdata)
292 continue;
293 if (j++ == idx) {
294 if (MPATH_EXPIRED(node->mpath)) {
295 spin_lock_bh(&node->mpath->state_lock);
296 if (MPATH_EXPIRED(node->mpath))
297 node->mpath->flags &= ~MESH_PATH_ACTIVE;
298 spin_unlock_bh(&node->mpath->state_lock);
299 }
300 return node->mpath;
301 }
302 }
303
304 return NULL;
305}
306
307/**
308 * mesh_path_add - allocate and add a new path to the mesh path table
309 * @addr: destination address of the path (ETH_ALEN length)
310 * @sdata: local subif
311 *
312 * Returns: 0 on success
313 *
314 * State: the initial state of the new path is set to 0
315 */
316int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
317{
318 struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
319 struct ieee80211_local *local = sdata->local;
320 struct mesh_table *tbl;
321 struct mesh_path *mpath, *new_mpath;
322 struct mpath_node *node, *new_node;
323 struct hlist_head *bucket;
324 struct hlist_node *n;
325 int grow = 0;
326 int err = 0;
327 u32 hash_idx;
328
329 if (memcmp(dst, sdata->vif.addr, ETH_ALEN) == 0)
330 /* never add ourselves as neighbours */
331 return -ENOTSUPP;
332
333 if (is_multicast_ether_addr(dst))
334 return -ENOTSUPP;
335
336 if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
337 return -ENOSPC;
338
339 err = -ENOMEM;
340 new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
341 if (!new_mpath)
342 goto err_path_alloc;
343
344 new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
345 if (!new_node)
346 goto err_node_alloc;
347
348 read_lock_bh(&pathtbl_resize_lock);
349 memcpy(new_mpath->dst, dst, ETH_ALEN);
350 new_mpath->sdata = sdata;
351 new_mpath->flags = 0;
352 skb_queue_head_init(&new_mpath->frame_queue);
353 new_node->mpath = new_mpath;
354 new_mpath->timer.data = (unsigned long) new_mpath;
355 new_mpath->timer.function = mesh_path_timer;
356 new_mpath->exp_time = jiffies;
357 spin_lock_init(&new_mpath->state_lock);
358 init_timer(&new_mpath->timer);
359
360 tbl = resize_dereference_mesh_paths();
361
362 hash_idx = mesh_table_hash(dst, sdata, tbl);
363 bucket = &tbl->hash_buckets[hash_idx];
364
365 spin_lock_bh(&tbl->hashwlock[hash_idx]);
366
367 err = -EEXIST;
368 hlist_for_each_entry(node, n, bucket, list) {
369 mpath = node->mpath;
370 if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
371 goto err_exists;
372 }
373
374 hlist_add_head_rcu(&new_node->list, bucket);
375 if (atomic_inc_return(&tbl->entries) >=
376 tbl->mean_chain_len * (tbl->hash_mask + 1))
377 grow = 1;
378
379 mesh_paths_generation++;
380
381 spin_unlock_bh(&tbl->hashwlock[hash_idx]);
382 read_unlock_bh(&pathtbl_resize_lock);
383 if (grow) {
384 set_bit(MESH_WORK_GROW_MPATH_TABLE, &ifmsh->wrkq_flags);
385 ieee80211_queue_work(&local->hw, &sdata->work);
386 }
387 return 0;
388
389err_exists:
390 spin_unlock_bh(&tbl->hashwlock[hash_idx]);
391 read_unlock_bh(&pathtbl_resize_lock);
392 kfree(new_node);
393err_node_alloc:
394 kfree(new_mpath);
395err_path_alloc:
396 atomic_dec(&sdata->u.mesh.mpaths);
397 return err;
398}
399
400static void mesh_table_free_rcu(struct rcu_head *rcu)
401{
402 struct mesh_table *tbl = container_of(rcu, struct mesh_table, rcu_head);
403
404 mesh_table_free(tbl, false);
405}
406
407void mesh_mpath_table_grow(void)
408{
409 struct mesh_table *oldtbl, *newtbl;
410
411 write_lock_bh(&pathtbl_resize_lock);
412 oldtbl = resize_dereference_mesh_paths();
413 newtbl = mesh_table_alloc(oldtbl->size_order + 1);
414 if (!newtbl)
415 goto out;
416 if (mesh_table_grow(oldtbl, newtbl) < 0) {
417 __mesh_table_free(newtbl);
418 goto out;
419 }
420 rcu_assign_pointer(mesh_paths, newtbl);
421
422 call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
423
424 out:
425 write_unlock_bh(&pathtbl_resize_lock);
426}
427
428void mesh_mpp_table_grow(void)
429{
430 struct mesh_table *oldtbl, *newtbl;
431
432 write_lock_bh(&pathtbl_resize_lock);
433 oldtbl = resize_dereference_mpp_paths();
434 newtbl = mesh_table_alloc(oldtbl->size_order + 1);
435 if (!newtbl)
436 goto out;
437 if (mesh_table_grow(oldtbl, newtbl) < 0) {
438 __mesh_table_free(newtbl);
439 goto out;
440 }
441 rcu_assign_pointer(mpp_paths, newtbl);
442 call_rcu(&oldtbl->rcu_head, mesh_table_free_rcu);
443
444 out:
445 write_unlock_bh(&pathtbl_resize_lock);
446}
447
448int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
449{
450 struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
451 struct ieee80211_local *local = sdata->local;
452 struct mesh_table *tbl;
453 struct mesh_path *mpath, *new_mpath;
454 struct mpath_node *node, *new_node;
455 struct hlist_head *bucket;
456 struct hlist_node *n;
457 int grow = 0;
458 int err = 0;
459 u32 hash_idx;
460
461 if (memcmp(dst, sdata->vif.addr, ETH_ALEN) == 0)
462 /* never add ourselves as neighbours */
463 return -ENOTSUPP;
464
465 if (is_multicast_ether_addr(dst))
466 return -ENOTSUPP;
467
468 err = -ENOMEM;
469 new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
470 if (!new_mpath)
471 goto err_path_alloc;
472
473 new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
474 if (!new_node)
475 goto err_node_alloc;
476
477 read_lock_bh(&pathtbl_resize_lock);
478 memcpy(new_mpath->dst, dst, ETH_ALEN);
479 memcpy(new_mpath->mpp, mpp, ETH_ALEN);
480 new_mpath->sdata = sdata;
481 new_mpath->flags = 0;
482 skb_queue_head_init(&new_mpath->frame_queue);
483 new_node->mpath = new_mpath;
484 new_mpath->exp_time = jiffies;
485 spin_lock_init(&new_mpath->state_lock);
486
487 tbl = resize_dereference_mpp_paths();
488
489 hash_idx = mesh_table_hash(dst, sdata, tbl);
490 bucket = &tbl->hash_buckets[hash_idx];
491
492 spin_lock_bh(&tbl->hashwlock[hash_idx]);
493
494 err = -EEXIST;
495 hlist_for_each_entry(node, n, bucket, list) {
496 mpath = node->mpath;
497 if (mpath->sdata == sdata && memcmp(dst, mpath->dst, ETH_ALEN) == 0)
498 goto err_exists;
499 }
500
501 hlist_add_head_rcu(&new_node->list, bucket);
502 if (atomic_inc_return(&tbl->entries) >=
503 tbl->mean_chain_len * (tbl->hash_mask + 1))
504 grow = 1;
505
506 spin_unlock_bh(&tbl->hashwlock[hash_idx]);
507 read_unlock_bh(&pathtbl_resize_lock);
508 if (grow) {
509 set_bit(MESH_WORK_GROW_MPP_TABLE, &ifmsh->wrkq_flags);
510 ieee80211_queue_work(&local->hw, &sdata->work);
511 }
512 return 0;
513
514err_exists:
515 spin_unlock_bh(&tbl->hashwlock[hash_idx]);
516 read_unlock_bh(&pathtbl_resize_lock);
517 kfree(new_node);
518err_node_alloc:
519 kfree(new_mpath);
520err_path_alloc:
521 return err;
522}
523
524
525/**
526 * mesh_plink_broken - deactivates paths and sends perr when a link breaks
527 *
528 * @sta: broken peer link
529 *
530 * This function must be called from the rate control algorithm if enough
531 * delivery errors suggest that a peer link is no longer usable.
532 */
533void mesh_plink_broken(struct sta_info *sta)
534{
535 struct mesh_table *tbl;
536 static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
537 struct mesh_path *mpath;
538 struct mpath_node *node;
539 struct hlist_node *p;
540 struct ieee80211_sub_if_data *sdata = sta->sdata;
541 int i;
542
543 rcu_read_lock();
544 tbl = rcu_dereference(mesh_paths);
545 for_each_mesh_entry(tbl, p, node, i) {
546 mpath = node->mpath;
547 spin_lock_bh(&mpath->state_lock);
548 if (rcu_dereference(mpath->next_hop) == sta &&
549 mpath->flags & MESH_PATH_ACTIVE &&
550 !(mpath->flags & MESH_PATH_FIXED)) {
551 mpath->flags &= ~MESH_PATH_ACTIVE;
552 ++mpath->sn;
553 spin_unlock_bh(&mpath->state_lock);
554 mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
555 mpath->dst, cpu_to_le32(mpath->sn),
556 cpu_to_le16(PERR_RCODE_DEST_UNREACH),
557 bcast, sdata);
558 } else
559 spin_unlock_bh(&mpath->state_lock);
560 }
561 rcu_read_unlock();
562}
563
564/**
565 * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
566 *
567 * @sta - mesh peer to match
568 *
569 * RCU notes: this function is called when a mesh plink transitions from
570 * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
571 * allows path creation. This will happen before the sta can be freed (because
572 * sta_info_destroy() calls this) so any reader in a rcu read block will be
573 * protected against the plink disappearing.
574 */
575void mesh_path_flush_by_nexthop(struct sta_info *sta)
576{
577 struct mesh_table *tbl;
578 struct mesh_path *mpath;
579 struct mpath_node *node;
580 struct hlist_node *p;
581 int i;
582
583 rcu_read_lock();
584 tbl = rcu_dereference(mesh_paths);
585 for_each_mesh_entry(tbl, p, node, i) {
586 mpath = node->mpath;
587 if (rcu_dereference(mpath->next_hop) == sta)
588 mesh_path_del(mpath->dst, mpath->sdata);
589 }
590 rcu_read_unlock();
591}
592
593void mesh_path_flush(struct ieee80211_sub_if_data *sdata)
594{
595 struct mesh_table *tbl;
596 struct mesh_path *mpath;
597 struct mpath_node *node;
598 struct hlist_node *p;
599 int i;
600
601 rcu_read_lock();
602 tbl = rcu_dereference(mesh_paths);
603 for_each_mesh_entry(tbl, p, node, i) {
604 mpath = node->mpath;
605 if (mpath->sdata == sdata)
606 mesh_path_del(mpath->dst, mpath->sdata);
607 }
608 rcu_read_unlock();
609}
610
611static void mesh_path_node_reclaim(struct rcu_head *rp)
612{
613 struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
614 struct ieee80211_sub_if_data *sdata = node->mpath->sdata;
615
616 del_timer_sync(&node->mpath->timer);
617 atomic_dec(&sdata->u.mesh.mpaths);
618 kfree(node->mpath);
619 kfree(node);
620}
621
622/**
623 * mesh_path_del - delete a mesh path from the table
624 *
625 * @addr: dst address (ETH_ALEN length)
626 * @sdata: local subif
627 *
628 * Returns: 0 if successful
629 */
630int mesh_path_del(u8 *addr, struct ieee80211_sub_if_data *sdata)
631{
632 struct mesh_table *tbl;
633 struct mesh_path *mpath;
634 struct mpath_node *node;
635 struct hlist_head *bucket;
636 struct hlist_node *n;
637 int hash_idx;
638 int err = 0;
639
640 read_lock_bh(&pathtbl_resize_lock);
641 tbl = resize_dereference_mesh_paths();
642 hash_idx = mesh_table_hash(addr, sdata, tbl);
643 bucket = &tbl->hash_buckets[hash_idx];
644
645 spin_lock_bh(&tbl->hashwlock[hash_idx]);
646 hlist_for_each_entry(node, n, bucket, list) {
647 mpath = node->mpath;
648 if (mpath->sdata == sdata &&
649 memcmp(addr, mpath->dst, ETH_ALEN) == 0) {
650 spin_lock(&mpath->state_lock);
651 mpath->flags |= MESH_PATH_RESOLVING;
652 hlist_del_rcu(&node->list);
653 call_rcu(&node->rcu, mesh_path_node_reclaim);
654 atomic_dec(&tbl->entries);
655 spin_unlock(&mpath->state_lock);
656 goto enddel;
657 }
658 }
659
660 err = -ENXIO;
661enddel:
662 mesh_paths_generation++;
663 spin_unlock_bh(&tbl->hashwlock[hash_idx]);
664 read_unlock_bh(&pathtbl_resize_lock);
665 return err;
666}
667
668/**
669 * mesh_path_tx_pending - sends pending frames in a mesh path queue
670 *
671 * @mpath: mesh path to activate
672 *
673 * Locking: the state_lock of the mpath structure must NOT be held when calling
674 * this function.
675 */
676void mesh_path_tx_pending(struct mesh_path *mpath)
677{
678 if (mpath->flags & MESH_PATH_ACTIVE)
679 ieee80211_add_pending_skbs(mpath->sdata->local,
680 &mpath->frame_queue);
681}
682
683/**
684 * mesh_path_discard_frame - discard a frame whose path could not be resolved
685 *
686 * @skb: frame to discard
687 * @sdata: network subif the frame was to be sent through
688 *
689 * If the frame was being forwarded from another MP, a PERR frame will be sent
690 * to the precursor. The precursor's address (i.e. the previous hop) was saved
691 * in addr1 of the frame-to-be-forwarded, and would only be overwritten once
692 * the destination is successfully resolved.
693 *
694 * Locking: the function must me called within a rcu_read_lock region
695 */
696void mesh_path_discard_frame(struct sk_buff *skb,
697 struct ieee80211_sub_if_data *sdata)
698{
699 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
700 struct mesh_path *mpath;
701 u32 sn = 0;
702
703 if (memcmp(hdr->addr4, sdata->vif.addr, ETH_ALEN) != 0) {
704 u8 *ra, *da;
705
706 da = hdr->addr3;
707 ra = hdr->addr1;
708 mpath = mesh_path_lookup(da, sdata);
709 if (mpath)
710 sn = ++mpath->sn;
711 mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl, skb->data,
712 cpu_to_le32(sn),
713 cpu_to_le16(PERR_RCODE_NO_ROUTE), ra, sdata);
714 }
715
716 kfree_skb(skb);
717 sdata->u.mesh.mshstats.dropped_frames_no_route++;
718}
719
720/**
721 * mesh_path_flush_pending - free the pending queue of a mesh path
722 *
723 * @mpath: mesh path whose queue has to be freed
724 *
725 * Locking: the function must me called within a rcu_read_lock region
726 */
727void mesh_path_flush_pending(struct mesh_path *mpath)
728{
729 struct sk_buff *skb;
730
731 while ((skb = skb_dequeue(&mpath->frame_queue)) &&
732 (mpath->flags & MESH_PATH_ACTIVE))
733 mesh_path_discard_frame(skb, mpath->sdata);
734}
735
736/**
737 * mesh_path_fix_nexthop - force a specific next hop for a mesh path
738 *
739 * @mpath: the mesh path to modify
740 * @next_hop: the next hop to force
741 *
742 * Locking: this function must be called holding mpath->state_lock
743 */
744void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
745{
746 spin_lock_bh(&mpath->state_lock);
747 mesh_path_assign_nexthop(mpath, next_hop);
748 mpath->sn = 0xffff;
749 mpath->metric = 0;
750 mpath->hop_count = 0;
751 mpath->exp_time = 0;
752 mpath->flags |= MESH_PATH_FIXED;
753 mesh_path_activate(mpath);
754 spin_unlock_bh(&mpath->state_lock);
755 mesh_path_tx_pending(mpath);
756}
757
758static void mesh_path_node_free(struct hlist_node *p, bool free_leafs)
759{
760 struct mesh_path *mpath;
761 struct mpath_node *node = hlist_entry(p, struct mpath_node, list);
762 mpath = node->mpath;
763 hlist_del_rcu(p);
764 if (free_leafs) {
765 del_timer_sync(&mpath->timer);
766 kfree(mpath);
767 }
768 kfree(node);
769}
770
771static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
772{
773 struct mesh_path *mpath;
774 struct mpath_node *node, *new_node;
775 u32 hash_idx;
776
777 new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
778 if (new_node == NULL)
779 return -ENOMEM;
780
781 node = hlist_entry(p, struct mpath_node, list);
782 mpath = node->mpath;
783 new_node->mpath = mpath;
784 hash_idx = mesh_table_hash(mpath->dst, mpath->sdata, newtbl);
785 hlist_add_head(&new_node->list,
786 &newtbl->hash_buckets[hash_idx]);
787 return 0;
788}
789
790int mesh_pathtbl_init(void)
791{
792 struct mesh_table *tbl_path, *tbl_mpp;
793
794 tbl_path = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
795 if (!tbl_path)
796 return -ENOMEM;
797 tbl_path->free_node = &mesh_path_node_free;
798 tbl_path->copy_node = &mesh_path_node_copy;
799 tbl_path->mean_chain_len = MEAN_CHAIN_LEN;
800
801 tbl_mpp = mesh_table_alloc(INIT_PATHS_SIZE_ORDER);
802 if (!tbl_mpp) {
803 mesh_table_free(tbl_path, true);
804 return -ENOMEM;
805 }
806 tbl_mpp->free_node = &mesh_path_node_free;
807 tbl_mpp->copy_node = &mesh_path_node_copy;
808 tbl_mpp->mean_chain_len = MEAN_CHAIN_LEN;
809
810 /* Need no locking since this is during init */
811 RCU_INIT_POINTER(mesh_paths, tbl_path);
812 RCU_INIT_POINTER(mpp_paths, tbl_mpp);
813
814 return 0;
815}
816
817void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
818{
819 struct mesh_table *tbl;
820 struct mesh_path *mpath;
821 struct mpath_node *node;
822 struct hlist_node *p;
823 int i;
824
825 rcu_read_lock();
826 tbl = rcu_dereference(mesh_paths);
827 for_each_mesh_entry(tbl, p, node, i) {
828 if (node->mpath->sdata != sdata)
829 continue;
830 mpath = node->mpath;
831 spin_lock_bh(&mpath->state_lock);
832 if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
833 (!(mpath->flags & MESH_PATH_FIXED)) &&
834 time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE)) {
835 spin_unlock_bh(&mpath->state_lock);
836 mesh_path_del(mpath->dst, mpath->sdata);
837 } else
838 spin_unlock_bh(&mpath->state_lock);
839 }
840 rcu_read_unlock();
841}
842
843void mesh_pathtbl_unregister(void)
844{
845 /* no need for locking during exit path */
846 mesh_table_free(rcu_dereference_raw(mesh_paths), true);
847 mesh_table_free(rcu_dereference_raw(mpp_paths), true);
848}