xref: /openbmc/linux/net/mac80211/mesh_pathtbl.c (revision b159eecc)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2008, 2009 open80211s Ltd.
4  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
5  */
6 
7 #include <linux/etherdevice.h>
8 #include <linux/list.h>
9 #include <linux/random.h>
10 #include <linux/slab.h>
11 #include <linux/spinlock.h>
12 #include <linux/string.h>
13 #include <net/mac80211.h>
14 #include "wme.h"
15 #include "ieee80211_i.h"
16 #include "mesh.h"
17 
18 static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);
19 
20 static u32 mesh_table_hash(const void *addr, u32 len, u32 seed)
21 {
22 	/* Use last four bytes of hw addr as hash index */
23 	return jhash_1word(__get_unaligned_cpu32((u8 *)addr + 2), seed);
24 }
25 
26 static const struct rhashtable_params mesh_rht_params = {
27 	.nelem_hint = 2,
28 	.automatic_shrinking = true,
29 	.key_len = ETH_ALEN,
30 	.key_offset = offsetof(struct mesh_path, dst),
31 	.head_offset = offsetof(struct mesh_path, rhash),
32 	.hashfn = mesh_table_hash,
33 };
34 
35 static inline bool mpath_expired(struct mesh_path *mpath)
36 {
37 	return (mpath->flags & MESH_PATH_ACTIVE) &&
38 	       time_after(jiffies, mpath->exp_time) &&
39 	       !(mpath->flags & MESH_PATH_FIXED);
40 }
41 
42 static void mesh_path_rht_free(void *ptr, void *tblptr)
43 {
44 	struct mesh_path *mpath = ptr;
45 	struct mesh_table *tbl = tblptr;
46 
47 	mesh_path_free_rcu(tbl, mpath);
48 }
49 
50 static struct mesh_table *mesh_table_alloc(void)
51 {
52 	struct mesh_table *newtbl;
53 
54 	newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
55 	if (!newtbl)
56 		return NULL;
57 
58 	INIT_HLIST_HEAD(&newtbl->known_gates);
59 	INIT_HLIST_HEAD(&newtbl->walk_head);
60 	atomic_set(&newtbl->entries,  0);
61 	spin_lock_init(&newtbl->gates_lock);
62 	spin_lock_init(&newtbl->walk_lock);
63 
64 	return newtbl;
65 }
66 
67 static void mesh_table_free(struct mesh_table *tbl)
68 {
69 	rhashtable_free_and_destroy(&tbl->rhead,
70 				    mesh_path_rht_free, tbl);
71 	kfree(tbl);
72 }
73 
74 /**
75  * mesh_path_assign_nexthop - update mesh path next hop
76  *
77  * @mpath: mesh path to update
78  * @sta: next hop to assign
79  *
80  * Locking: mpath->state_lock must be held when calling this function
81  */
82 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
83 {
84 	struct sk_buff *skb;
85 	struct ieee80211_hdr *hdr;
86 	unsigned long flags;
87 
88 	rcu_assign_pointer(mpath->next_hop, sta);
89 
90 	spin_lock_irqsave(&mpath->frame_queue.lock, flags);
91 	skb_queue_walk(&mpath->frame_queue, skb) {
92 		hdr = (struct ieee80211_hdr *) skb->data;
93 		memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
94 		memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
95 		ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
96 	}
97 
98 	spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
99 }
100 
101 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
102 			     struct mesh_path *gate_mpath)
103 {
104 	struct ieee80211_hdr *hdr;
105 	struct ieee80211s_hdr *mshdr;
106 	int mesh_hdrlen, hdrlen;
107 	char *next_hop;
108 
109 	hdr = (struct ieee80211_hdr *) skb->data;
110 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
111 	mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
112 
113 	if (!(mshdr->flags & MESH_FLAGS_AE)) {
114 		/* size of the fixed part of the mesh header */
115 		mesh_hdrlen = 6;
116 
117 		/* make room for the two extended addresses */
118 		skb_push(skb, 2 * ETH_ALEN);
119 		memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
120 
121 		hdr = (struct ieee80211_hdr *) skb->data;
122 
123 		/* we preserve the previous mesh header and only add
124 		 * the new addreses */
125 		mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
126 		mshdr->flags = MESH_FLAGS_AE_A5_A6;
127 		memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
128 		memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
129 	}
130 
131 	/* update next hop */
132 	hdr = (struct ieee80211_hdr *) skb->data;
133 	rcu_read_lock();
134 	next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
135 	memcpy(hdr->addr1, next_hop, ETH_ALEN);
136 	rcu_read_unlock();
137 	memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
138 	memcpy(hdr->addr3, dst_addr, ETH_ALEN);
139 }
140 
141 /**
142  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
143  *
144  * This function is used to transfer or copy frames from an unresolved mpath to
145  * a gate mpath.  The function also adds the Address Extension field and
146  * updates the next hop.
147  *
148  * If a frame already has an Address Extension field, only the next hop and
149  * destination addresses are updated.
150  *
151  * The gate mpath must be an active mpath with a valid mpath->next_hop.
152  *
153  * @gate_mpath: An active mpath the frames will be sent to (i.e. the gate)
154  * @from_mpath: The failed mpath
155  * @copy: When true, copy all the frames to the new mpath queue.  When false,
156  * move them.
157  */
158 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
159 				    struct mesh_path *from_mpath,
160 				    bool copy)
161 {
162 	struct sk_buff *skb, *fskb, *tmp;
163 	struct sk_buff_head failq;
164 	unsigned long flags;
165 
166 	if (WARN_ON(gate_mpath == from_mpath))
167 		return;
168 	if (WARN_ON(!gate_mpath->next_hop))
169 		return;
170 
171 	__skb_queue_head_init(&failq);
172 
173 	spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
174 	skb_queue_splice_init(&from_mpath->frame_queue, &failq);
175 	spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
176 
177 	skb_queue_walk_safe(&failq, fskb, tmp) {
178 		if (skb_queue_len(&gate_mpath->frame_queue) >=
179 				  MESH_FRAME_QUEUE_LEN) {
180 			mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
181 			break;
182 		}
183 
184 		skb = skb_copy(fskb, GFP_ATOMIC);
185 		if (WARN_ON(!skb))
186 			break;
187 
188 		prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
189 		skb_queue_tail(&gate_mpath->frame_queue, skb);
190 
191 		if (copy)
192 			continue;
193 
194 		__skb_unlink(fskb, &failq);
195 		kfree_skb(fskb);
196 	}
197 
198 	mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
199 		  gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
200 
201 	if (!copy)
202 		return;
203 
204 	spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
205 	skb_queue_splice(&failq, &from_mpath->frame_queue);
206 	spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
207 }
208 
209 
210 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
211 				      struct ieee80211_sub_if_data *sdata)
212 {
213 	struct mesh_path *mpath;
214 
215 	mpath = rhashtable_lookup(&tbl->rhead, dst, mesh_rht_params);
216 
217 	if (mpath && mpath_expired(mpath)) {
218 		spin_lock_bh(&mpath->state_lock);
219 		mpath->flags &= ~MESH_PATH_ACTIVE;
220 		spin_unlock_bh(&mpath->state_lock);
221 	}
222 	return mpath;
223 }
224 
225 /**
226  * mesh_path_lookup - look up a path in the mesh path table
227  * @sdata: local subif
228  * @dst: hardware address (ETH_ALEN length) of destination
229  *
230  * Returns: pointer to the mesh path structure, or NULL if not found
231  *
232  * Locking: must be called within a read rcu section.
233  */
234 struct mesh_path *
235 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
236 {
237 	return mpath_lookup(sdata->u.mesh.mesh_paths, dst, sdata);
238 }
239 
240 struct mesh_path *
241 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
242 {
243 	return mpath_lookup(sdata->u.mesh.mpp_paths, dst, sdata);
244 }
245 
246 static struct mesh_path *
247 __mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
248 {
249 	int i = 0;
250 	struct mesh_path *mpath;
251 
252 	hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
253 		if (i++ == idx)
254 			break;
255 	}
256 
257 	if (!mpath)
258 		return NULL;
259 
260 	if (mpath_expired(mpath)) {
261 		spin_lock_bh(&mpath->state_lock);
262 		mpath->flags &= ~MESH_PATH_ACTIVE;
263 		spin_unlock_bh(&mpath->state_lock);
264 	}
265 	return mpath;
266 }
267 
268 /**
269  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
270  * @idx: index
271  * @sdata: local subif, or NULL for all entries
272  *
273  * Returns: pointer to the mesh path structure, or NULL if not found.
274  *
275  * Locking: must be called within a read rcu section.
276  */
277 struct mesh_path *
278 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
279 {
280 	return __mesh_path_lookup_by_idx(sdata->u.mesh.mesh_paths, idx);
281 }
282 
283 /**
284  * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
285  * @idx: index
286  * @sdata: local subif, or NULL for all entries
287  *
288  * Returns: pointer to the proxy path structure, or NULL if not found.
289  *
290  * Locking: must be called within a read rcu section.
291  */
292 struct mesh_path *
293 mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
294 {
295 	return __mesh_path_lookup_by_idx(sdata->u.mesh.mpp_paths, idx);
296 }
297 
298 /**
299  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
300  * @mpath: gate path to add to table
301  */
302 int mesh_path_add_gate(struct mesh_path *mpath)
303 {
304 	struct mesh_table *tbl;
305 	int err;
306 
307 	rcu_read_lock();
308 	tbl = mpath->sdata->u.mesh.mesh_paths;
309 
310 	spin_lock_bh(&mpath->state_lock);
311 	if (mpath->is_gate) {
312 		err = -EEXIST;
313 		spin_unlock_bh(&mpath->state_lock);
314 		goto err_rcu;
315 	}
316 	mpath->is_gate = true;
317 	mpath->sdata->u.mesh.num_gates++;
318 
319 	spin_lock(&tbl->gates_lock);
320 	hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
321 	spin_unlock(&tbl->gates_lock);
322 
323 	spin_unlock_bh(&mpath->state_lock);
324 
325 	mpath_dbg(mpath->sdata,
326 		  "Mesh path: Recorded new gate: %pM. %d known gates\n",
327 		  mpath->dst, mpath->sdata->u.mesh.num_gates);
328 	err = 0;
329 err_rcu:
330 	rcu_read_unlock();
331 	return err;
332 }
333 
334 /**
335  * mesh_gate_del - remove a mesh gate from the list of known gates
336  * @tbl: table which holds our list of known gates
337  * @mpath: gate mpath
338  */
339 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
340 {
341 	lockdep_assert_held(&mpath->state_lock);
342 	if (!mpath->is_gate)
343 		return;
344 
345 	mpath->is_gate = false;
346 	spin_lock_bh(&tbl->gates_lock);
347 	hlist_del_rcu(&mpath->gate_list);
348 	mpath->sdata->u.mesh.num_gates--;
349 	spin_unlock_bh(&tbl->gates_lock);
350 
351 	mpath_dbg(mpath->sdata,
352 		  "Mesh path: Deleted gate: %pM. %d known gates\n",
353 		  mpath->dst, mpath->sdata->u.mesh.num_gates);
354 }
355 
356 /**
357  * mesh_gate_num - number of gates known to this interface
358  * @sdata: subif data
359  */
360 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
361 {
362 	return sdata->u.mesh.num_gates;
363 }
364 
365 static
366 struct mesh_path *mesh_path_new(struct ieee80211_sub_if_data *sdata,
367 				const u8 *dst, gfp_t gfp_flags)
368 {
369 	struct mesh_path *new_mpath;
370 
371 	new_mpath = kzalloc(sizeof(struct mesh_path), gfp_flags);
372 	if (!new_mpath)
373 		return NULL;
374 
375 	memcpy(new_mpath->dst, dst, ETH_ALEN);
376 	eth_broadcast_addr(new_mpath->rann_snd_addr);
377 	new_mpath->is_root = false;
378 	new_mpath->sdata = sdata;
379 	new_mpath->flags = 0;
380 	skb_queue_head_init(&new_mpath->frame_queue);
381 	new_mpath->exp_time = jiffies;
382 	spin_lock_init(&new_mpath->state_lock);
383 	timer_setup(&new_mpath->timer, mesh_path_timer, 0);
384 
385 	return new_mpath;
386 }
387 
388 /**
389  * mesh_path_add - allocate and add a new path to the mesh path table
390  * @dst: destination address of the path (ETH_ALEN length)
391  * @sdata: local subif
392  *
393  * Returns: 0 on success
394  *
395  * State: the initial state of the new path is set to 0
396  */
397 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
398 				const u8 *dst)
399 {
400 	struct mesh_table *tbl;
401 	struct mesh_path *mpath, *new_mpath;
402 
403 	if (ether_addr_equal(dst, sdata->vif.addr))
404 		/* never add ourselves as neighbours */
405 		return ERR_PTR(-ENOTSUPP);
406 
407 	if (is_multicast_ether_addr(dst))
408 		return ERR_PTR(-ENOTSUPP);
409 
410 	if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
411 		return ERR_PTR(-ENOSPC);
412 
413 	new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
414 	if (!new_mpath)
415 		return ERR_PTR(-ENOMEM);
416 
417 	tbl = sdata->u.mesh.mesh_paths;
418 	spin_lock_bh(&tbl->walk_lock);
419 	mpath = rhashtable_lookup_get_insert_fast(&tbl->rhead,
420 						  &new_mpath->rhash,
421 						  mesh_rht_params);
422 	if (!mpath)
423 		hlist_add_head(&new_mpath->walk_list, &tbl->walk_head);
424 	spin_unlock_bh(&tbl->walk_lock);
425 
426 	if (mpath) {
427 		kfree(new_mpath);
428 
429 		if (IS_ERR(mpath))
430 			return mpath;
431 
432 		new_mpath = mpath;
433 	}
434 
435 	sdata->u.mesh.mesh_paths_generation++;
436 	return new_mpath;
437 }
438 
439 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
440 		 const u8 *dst, const u8 *mpp)
441 {
442 	struct mesh_table *tbl;
443 	struct mesh_path *new_mpath;
444 	int ret;
445 
446 	if (ether_addr_equal(dst, sdata->vif.addr))
447 		/* never add ourselves as neighbours */
448 		return -ENOTSUPP;
449 
450 	if (is_multicast_ether_addr(dst))
451 		return -ENOTSUPP;
452 
453 	new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
454 
455 	if (!new_mpath)
456 		return -ENOMEM;
457 
458 	memcpy(new_mpath->mpp, mpp, ETH_ALEN);
459 	tbl = sdata->u.mesh.mpp_paths;
460 
461 	spin_lock_bh(&tbl->walk_lock);
462 	ret = rhashtable_lookup_insert_fast(&tbl->rhead,
463 					    &new_mpath->rhash,
464 					    mesh_rht_params);
465 	if (!ret)
466 		hlist_add_head_rcu(&new_mpath->walk_list, &tbl->walk_head);
467 	spin_unlock_bh(&tbl->walk_lock);
468 
469 	if (ret)
470 		kfree(new_mpath);
471 
472 	sdata->u.mesh.mpp_paths_generation++;
473 	return ret;
474 }
475 
476 
477 /**
478  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
479  *
480  * @sta: broken peer link
481  *
482  * This function must be called from the rate control algorithm if enough
483  * delivery errors suggest that a peer link is no longer usable.
484  */
485 void mesh_plink_broken(struct sta_info *sta)
486 {
487 	struct ieee80211_sub_if_data *sdata = sta->sdata;
488 	struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
489 	static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
490 	struct mesh_path *mpath;
491 
492 	rcu_read_lock();
493 	hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
494 		if (rcu_access_pointer(mpath->next_hop) == sta &&
495 		    mpath->flags & MESH_PATH_ACTIVE &&
496 		    !(mpath->flags & MESH_PATH_FIXED)) {
497 			spin_lock_bh(&mpath->state_lock);
498 			mpath->flags &= ~MESH_PATH_ACTIVE;
499 			++mpath->sn;
500 			spin_unlock_bh(&mpath->state_lock);
501 			mesh_path_error_tx(sdata,
502 				sdata->u.mesh.mshcfg.element_ttl,
503 				mpath->dst, mpath->sn,
504 				WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
505 		}
506 	}
507 	rcu_read_unlock();
508 }
509 
510 static void mesh_path_free_rcu(struct mesh_table *tbl,
511 			       struct mesh_path *mpath)
512 {
513 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
514 
515 	spin_lock_bh(&mpath->state_lock);
516 	mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
517 	mesh_gate_del(tbl, mpath);
518 	spin_unlock_bh(&mpath->state_lock);
519 	del_timer_sync(&mpath->timer);
520 	atomic_dec(&sdata->u.mesh.mpaths);
521 	atomic_dec(&tbl->entries);
522 	mesh_path_flush_pending(mpath);
523 	kfree_rcu(mpath, rcu);
524 }
525 
526 static void __mesh_path_del(struct mesh_table *tbl, struct mesh_path *mpath)
527 {
528 	hlist_del_rcu(&mpath->walk_list);
529 	rhashtable_remove_fast(&tbl->rhead, &mpath->rhash, mesh_rht_params);
530 	mesh_path_free_rcu(tbl, mpath);
531 }
532 
533 /**
534  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
535  *
536  * @sta: mesh peer to match
537  *
538  * RCU notes: this function is called when a mesh plink transitions from
539  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
540  * allows path creation. This will happen before the sta can be freed (because
541  * sta_info_destroy() calls this) so any reader in a rcu read block will be
542  * protected against the plink disappearing.
543  */
544 void mesh_path_flush_by_nexthop(struct sta_info *sta)
545 {
546 	struct ieee80211_sub_if_data *sdata = sta->sdata;
547 	struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
548 	struct mesh_path *mpath;
549 	struct hlist_node *n;
550 
551 	spin_lock_bh(&tbl->walk_lock);
552 	hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
553 		if (rcu_access_pointer(mpath->next_hop) == sta)
554 			__mesh_path_del(tbl, mpath);
555 	}
556 	spin_unlock_bh(&tbl->walk_lock);
557 }
558 
559 static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
560 			       const u8 *proxy)
561 {
562 	struct mesh_table *tbl = sdata->u.mesh.mpp_paths;
563 	struct mesh_path *mpath;
564 	struct hlist_node *n;
565 
566 	spin_lock_bh(&tbl->walk_lock);
567 	hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
568 		if (ether_addr_equal(mpath->mpp, proxy))
569 			__mesh_path_del(tbl, mpath);
570 	}
571 	spin_unlock_bh(&tbl->walk_lock);
572 }
573 
574 static void table_flush_by_iface(struct mesh_table *tbl)
575 {
576 	struct mesh_path *mpath;
577 	struct hlist_node *n;
578 
579 	spin_lock_bh(&tbl->walk_lock);
580 	hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
581 		__mesh_path_del(tbl, mpath);
582 	}
583 	spin_unlock_bh(&tbl->walk_lock);
584 }
585 
586 /**
587  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
588  *
589  * This function deletes both mesh paths as well as mesh portal paths.
590  *
591  * @sdata: interface data to match
592  *
593  */
594 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
595 {
596 	table_flush_by_iface(sdata->u.mesh.mesh_paths);
597 	table_flush_by_iface(sdata->u.mesh.mpp_paths);
598 }
599 
600 /**
601  * table_path_del - delete a path from the mesh or mpp table
602  *
603  * @tbl: mesh or mpp path table
604  * @sdata: local subif
605  * @addr: dst address (ETH_ALEN length)
606  *
607  * Returns: 0 if successful
608  */
609 static int table_path_del(struct mesh_table *tbl,
610 			  struct ieee80211_sub_if_data *sdata,
611 			  const u8 *addr)
612 {
613 	struct mesh_path *mpath;
614 
615 	spin_lock_bh(&tbl->walk_lock);
616 	mpath = rhashtable_lookup_fast(&tbl->rhead, addr, mesh_rht_params);
617 	if (!mpath) {
618 		spin_unlock_bh(&tbl->walk_lock);
619 		return -ENXIO;
620 	}
621 
622 	__mesh_path_del(tbl, mpath);
623 	spin_unlock_bh(&tbl->walk_lock);
624 	return 0;
625 }
626 
627 
628 /**
629  * mesh_path_del - delete a mesh path from the table
630  *
631  * @addr: dst address (ETH_ALEN length)
632  * @sdata: local subif
633  *
634  * Returns: 0 if successful
635  */
636 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
637 {
638 	int err;
639 
640 	/* flush relevant mpp entries first */
641 	mpp_flush_by_proxy(sdata, addr);
642 
643 	err = table_path_del(sdata->u.mesh.mesh_paths, sdata, addr);
644 	sdata->u.mesh.mesh_paths_generation++;
645 	return err;
646 }
647 
648 /**
649  * mesh_path_tx_pending - sends pending frames in a mesh path queue
650  *
651  * @mpath: mesh path to activate
652  *
653  * Locking: the state_lock of the mpath structure must NOT be held when calling
654  * this function.
655  */
656 void mesh_path_tx_pending(struct mesh_path *mpath)
657 {
658 	if (mpath->flags & MESH_PATH_ACTIVE)
659 		ieee80211_add_pending_skbs(mpath->sdata->local,
660 				&mpath->frame_queue);
661 }
662 
663 /**
664  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
665  *
666  * @mpath: mesh path whose queue will be emptied
667  *
668  * If there is only one gate, the frames are transferred from the failed mpath
669  * queue to that gate's queue.  If there are more than one gates, the frames
670  * are copied from each gate to the next.  After frames are copied, the
671  * mpath queues are emptied onto the transmission queue.
672  */
673 int mesh_path_send_to_gates(struct mesh_path *mpath)
674 {
675 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
676 	struct mesh_table *tbl;
677 	struct mesh_path *from_mpath = mpath;
678 	struct mesh_path *gate;
679 	bool copy = false;
680 
681 	tbl = sdata->u.mesh.mesh_paths;
682 
683 	rcu_read_lock();
684 	hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
685 		if (gate->flags & MESH_PATH_ACTIVE) {
686 			mpath_dbg(sdata, "Forwarding to %pM\n", gate->dst);
687 			mesh_path_move_to_queue(gate, from_mpath, copy);
688 			from_mpath = gate;
689 			copy = true;
690 		} else {
691 			mpath_dbg(sdata,
692 				  "Not forwarding to %pM (flags %#x)\n",
693 				  gate->dst, gate->flags);
694 		}
695 	}
696 
697 	hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
698 		mpath_dbg(sdata, "Sending to %pM\n", gate->dst);
699 		mesh_path_tx_pending(gate);
700 	}
701 	rcu_read_unlock();
702 
703 	return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
704 }
705 
706 /**
707  * mesh_path_discard_frame - discard a frame whose path could not be resolved
708  *
709  * @skb: frame to discard
710  * @sdata: network subif the frame was to be sent through
711  *
712  * Locking: the function must me called within a rcu_read_lock region
713  */
714 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
715 			     struct sk_buff *skb)
716 {
717 	kfree_skb(skb);
718 	sdata->u.mesh.mshstats.dropped_frames_no_route++;
719 }
720 
721 /**
722  * mesh_path_flush_pending - free the pending queue of a mesh path
723  *
724  * @mpath: mesh path whose queue has to be freed
725  *
726  * Locking: the function must me called within a rcu_read_lock region
727  */
728 void mesh_path_flush_pending(struct mesh_path *mpath)
729 {
730 	struct sk_buff *skb;
731 
732 	while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
733 		mesh_path_discard_frame(mpath->sdata, skb);
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  */
744 void 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 | MESH_PATH_SN_VALID;
753 	mesh_path_activate(mpath);
754 	spin_unlock_bh(&mpath->state_lock);
755 	ewma_mesh_fail_avg_init(&next_hop->mesh->fail_avg);
756 	/* init it at a low value - 0 start is tricky */
757 	ewma_mesh_fail_avg_add(&next_hop->mesh->fail_avg, 1);
758 	mesh_path_tx_pending(mpath);
759 }
760 
761 int mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
762 {
763 	struct mesh_table *tbl_path, *tbl_mpp;
764 	int ret;
765 
766 	tbl_path = mesh_table_alloc();
767 	if (!tbl_path)
768 		return -ENOMEM;
769 
770 	tbl_mpp = mesh_table_alloc();
771 	if (!tbl_mpp) {
772 		ret = -ENOMEM;
773 		goto free_path;
774 	}
775 
776 	rhashtable_init(&tbl_path->rhead, &mesh_rht_params);
777 	rhashtable_init(&tbl_mpp->rhead, &mesh_rht_params);
778 
779 	sdata->u.mesh.mesh_paths = tbl_path;
780 	sdata->u.mesh.mpp_paths = tbl_mpp;
781 
782 	return 0;
783 
784 free_path:
785 	mesh_table_free(tbl_path);
786 	return ret;
787 }
788 
789 static
790 void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
791 			  struct mesh_table *tbl)
792 {
793 	struct mesh_path *mpath;
794 	struct hlist_node *n;
795 
796 	spin_lock_bh(&tbl->walk_lock);
797 	hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
798 		if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
799 		    (!(mpath->flags & MESH_PATH_FIXED)) &&
800 		     time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
801 			__mesh_path_del(tbl, mpath);
802 	}
803 	spin_unlock_bh(&tbl->walk_lock);
804 }
805 
806 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
807 {
808 	mesh_path_tbl_expire(sdata, sdata->u.mesh.mesh_paths);
809 	mesh_path_tbl_expire(sdata, sdata->u.mesh.mpp_paths);
810 }
811 
812 void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
813 {
814 	mesh_table_free(sdata->u.mesh.mesh_paths);
815 	mesh_table_free(sdata->u.mesh.mpp_paths);
816 }
817