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
 18static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);
 19
 20static 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
 26static 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
 35static 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
 42static 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
 50static 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
 67static 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 */
 82void 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
101static 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 */
158static 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
210static 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 */
234struct mesh_path *
235mesh_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
240struct mesh_path *
241mpp_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
246static 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 */
277struct mesh_path *
278mesh_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 */
292struct mesh_path *
293mpp_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 */
302int 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;
329err_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 */
339static 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 */
360int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
361{
362	return sdata->u.mesh.num_gates;
363}
364
365static
366struct 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 */
397struct 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
439int 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 */
485void 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
510static 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
526static 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 */
544void 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
559static 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
574static 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 */
594void 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 */
609static 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 */
636int 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 */
656void 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 */
673int 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 */
714void 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 */
728void 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 */
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 | 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
761int 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
784free_path:
785	mesh_table_free(tbl_path);
786	return ret;
787}
788
789static
790void 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
806void 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
812void 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}