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1 /*
2  * Copyright (c) 2008, 2009 open80211s Ltd.
3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  */
9 
10 #include <linux/etherdevice.h>
11 #include <linux/list.h>
12 #include <linux/random.h>
13 #include <linux/slab.h>
14 #include <linux/spinlock.h>
15 #include <linux/string.h>
16 #include <net/mac80211.h>
17 #include "wme.h"
18 #include "ieee80211_i.h"
19 #include "mesh.h"
20 
21 static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);
22 
mesh_table_hash(const void * addr,u32 len,u32 seed)23 static u32 mesh_table_hash(const void *addr, u32 len, u32 seed)
24 {
25 	/* Use last four bytes of hw addr as hash index */
26 	return jhash_1word(*(u32 *)(addr+2), seed);
27 }
28 
29 static const struct rhashtable_params mesh_rht_params = {
30 	.nelem_hint = 2,
31 	.automatic_shrinking = true,
32 	.key_len = ETH_ALEN,
33 	.key_offset = offsetof(struct mesh_path, dst),
34 	.head_offset = offsetof(struct mesh_path, rhash),
35 	.hashfn = mesh_table_hash,
36 };
37 
mpath_expired(struct mesh_path * mpath)38 static inline bool mpath_expired(struct mesh_path *mpath)
39 {
40 	return (mpath->flags & MESH_PATH_ACTIVE) &&
41 	       time_after(jiffies, mpath->exp_time) &&
42 	       !(mpath->flags & MESH_PATH_FIXED);
43 }
44 
mesh_path_rht_free(void * ptr,void * tblptr)45 static void mesh_path_rht_free(void *ptr, void *tblptr)
46 {
47 	struct mesh_path *mpath = ptr;
48 	struct mesh_table *tbl = tblptr;
49 
50 	mesh_path_free_rcu(tbl, mpath);
51 }
52 
mesh_table_alloc(void)53 static struct mesh_table *mesh_table_alloc(void)
54 {
55 	struct mesh_table *newtbl;
56 
57 	newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
58 	if (!newtbl)
59 		return NULL;
60 
61 	INIT_HLIST_HEAD(&newtbl->known_gates);
62 	atomic_set(&newtbl->entries,  0);
63 	spin_lock_init(&newtbl->gates_lock);
64 
65 	return newtbl;
66 }
67 
mesh_table_free(struct mesh_table * tbl)68 static void mesh_table_free(struct mesh_table *tbl)
69 {
70 	rhashtable_free_and_destroy(&tbl->rhead,
71 				    mesh_path_rht_free, tbl);
72 	kfree(tbl);
73 }
74 
75 /**
76  *
77  * mesh_path_assign_nexthop - update mesh path next hop
78  *
79  * @mpath: mesh path to update
80  * @sta: next hop to assign
81  *
82  * Locking: mpath->state_lock must be held when calling this function
83  */
mesh_path_assign_nexthop(struct mesh_path * mpath,struct sta_info * sta)84 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
85 {
86 	struct sk_buff *skb;
87 	struct ieee80211_hdr *hdr;
88 	unsigned long flags;
89 
90 	rcu_assign_pointer(mpath->next_hop, sta);
91 
92 	spin_lock_irqsave(&mpath->frame_queue.lock, flags);
93 	skb_queue_walk(&mpath->frame_queue, skb) {
94 		hdr = (struct ieee80211_hdr *) skb->data;
95 		memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
96 		memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
97 		ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
98 	}
99 
100 	spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
101 }
102 
prepare_for_gate(struct sk_buff * skb,char * dst_addr,struct mesh_path * gate_mpath)103 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
104 			     struct mesh_path *gate_mpath)
105 {
106 	struct ieee80211_hdr *hdr;
107 	struct ieee80211s_hdr *mshdr;
108 	int mesh_hdrlen, hdrlen;
109 	char *next_hop;
110 
111 	hdr = (struct ieee80211_hdr *) skb->data;
112 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
113 	mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
114 
115 	if (!(mshdr->flags & MESH_FLAGS_AE)) {
116 		/* size of the fixed part of the mesh header */
117 		mesh_hdrlen = 6;
118 
119 		/* make room for the two extended addresses */
120 		skb_push(skb, 2 * ETH_ALEN);
121 		memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
122 
123 		hdr = (struct ieee80211_hdr *) skb->data;
124 
125 		/* we preserve the previous mesh header and only add
126 		 * the new addreses */
127 		mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
128 		mshdr->flags = MESH_FLAGS_AE_A5_A6;
129 		memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
130 		memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
131 	}
132 
133 	/* update next hop */
134 	hdr = (struct ieee80211_hdr *) skb->data;
135 	rcu_read_lock();
136 	next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
137 	memcpy(hdr->addr1, next_hop, ETH_ALEN);
138 	rcu_read_unlock();
139 	memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
140 	memcpy(hdr->addr3, dst_addr, ETH_ALEN);
141 }
142 
143 /**
144  *
145  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
146  *
147  * This function is used to transfer or copy frames from an unresolved mpath to
148  * a gate mpath.  The function also adds the Address Extension field and
149  * updates the next hop.
150  *
151  * If a frame already has an Address Extension field, only the next hop and
152  * destination addresses are updated.
153  *
154  * The gate mpath must be an active mpath with a valid mpath->next_hop.
155  *
156  * @mpath: An active mpath the frames will be sent to (i.e. the gate)
157  * @from_mpath: The failed mpath
158  * @copy: When true, copy all the frames to the new mpath queue.  When false,
159  * move them.
160  */
mesh_path_move_to_queue(struct mesh_path * gate_mpath,struct mesh_path * from_mpath,bool copy)161 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
162 				    struct mesh_path *from_mpath,
163 				    bool copy)
164 {
165 	struct sk_buff *skb, *fskb, *tmp;
166 	struct sk_buff_head failq;
167 	unsigned long flags;
168 
169 	if (WARN_ON(gate_mpath == from_mpath))
170 		return;
171 	if (WARN_ON(!gate_mpath->next_hop))
172 		return;
173 
174 	__skb_queue_head_init(&failq);
175 
176 	spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
177 	skb_queue_splice_init(&from_mpath->frame_queue, &failq);
178 	spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
179 
180 	skb_queue_walk_safe(&failq, fskb, tmp) {
181 		if (skb_queue_len(&gate_mpath->frame_queue) >=
182 				  MESH_FRAME_QUEUE_LEN) {
183 			mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
184 			break;
185 		}
186 
187 		skb = skb_copy(fskb, GFP_ATOMIC);
188 		if (WARN_ON(!skb))
189 			break;
190 
191 		prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
192 		skb_queue_tail(&gate_mpath->frame_queue, skb);
193 
194 		if (copy)
195 			continue;
196 
197 		__skb_unlink(fskb, &failq);
198 		kfree_skb(fskb);
199 	}
200 
201 	mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
202 		  gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
203 
204 	if (!copy)
205 		return;
206 
207 	spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
208 	skb_queue_splice(&failq, &from_mpath->frame_queue);
209 	spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
210 }
211 
212 
mpath_lookup(struct mesh_table * tbl,const u8 * dst,struct ieee80211_sub_if_data * sdata)213 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
214 				      struct ieee80211_sub_if_data *sdata)
215 {
216 	struct mesh_path *mpath;
217 
218 	mpath = rhashtable_lookup_fast(&tbl->rhead, dst, mesh_rht_params);
219 
220 	if (mpath && mpath_expired(mpath)) {
221 		spin_lock_bh(&mpath->state_lock);
222 		mpath->flags &= ~MESH_PATH_ACTIVE;
223 		spin_unlock_bh(&mpath->state_lock);
224 	}
225 	return mpath;
226 }
227 
228 /**
229  * mesh_path_lookup - look up a path in the mesh path table
230  * @sdata: local subif
231  * @dst: hardware address (ETH_ALEN length) of destination
232  *
233  * Returns: pointer to the mesh path structure, or NULL if not found
234  *
235  * Locking: must be called within a read rcu section.
236  */
237 struct mesh_path *
mesh_path_lookup(struct ieee80211_sub_if_data * sdata,const u8 * dst)238 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
239 {
240 	return mpath_lookup(sdata->u.mesh.mesh_paths, dst, sdata);
241 }
242 
243 struct mesh_path *
mpp_path_lookup(struct ieee80211_sub_if_data * sdata,const u8 * dst)244 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
245 {
246 	return mpath_lookup(sdata->u.mesh.mpp_paths, dst, sdata);
247 }
248 
249 static struct mesh_path *
__mesh_path_lookup_by_idx(struct mesh_table * tbl,int idx)250 __mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
251 {
252 	int i = 0, ret;
253 	struct mesh_path *mpath = NULL;
254 	struct rhashtable_iter iter;
255 
256 	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
257 	if (ret)
258 		return NULL;
259 
260 	ret = rhashtable_walk_start(&iter);
261 	if (ret && ret != -EAGAIN)
262 		goto err;
263 
264 	while ((mpath = rhashtable_walk_next(&iter))) {
265 		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
266 			continue;
267 		if (IS_ERR(mpath))
268 			break;
269 		if (i++ == idx)
270 			break;
271 	}
272 err:
273 	rhashtable_walk_stop(&iter);
274 	rhashtable_walk_exit(&iter);
275 
276 	if (IS_ERR(mpath) || !mpath)
277 		return NULL;
278 
279 	if (mpath_expired(mpath)) {
280 		spin_lock_bh(&mpath->state_lock);
281 		mpath->flags &= ~MESH_PATH_ACTIVE;
282 		spin_unlock_bh(&mpath->state_lock);
283 	}
284 	return mpath;
285 }
286 
287 /**
288  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
289  * @idx: index
290  * @sdata: local subif, or NULL for all entries
291  *
292  * Returns: pointer to the mesh path structure, or NULL if not found.
293  *
294  * Locking: must be called within a read rcu section.
295  */
296 struct mesh_path *
mesh_path_lookup_by_idx(struct ieee80211_sub_if_data * sdata,int idx)297 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
298 {
299 	return __mesh_path_lookup_by_idx(sdata->u.mesh.mesh_paths, idx);
300 }
301 
302 /**
303  * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
304  * @idx: index
305  * @sdata: local subif, or NULL for all entries
306  *
307  * Returns: pointer to the proxy path structure, or NULL if not found.
308  *
309  * Locking: must be called within a read rcu section.
310  */
311 struct mesh_path *
mpp_path_lookup_by_idx(struct ieee80211_sub_if_data * sdata,int idx)312 mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
313 {
314 	return __mesh_path_lookup_by_idx(sdata->u.mesh.mpp_paths, idx);
315 }
316 
317 /**
318  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
319  * @mpath: gate path to add to table
320  */
mesh_path_add_gate(struct mesh_path * mpath)321 int mesh_path_add_gate(struct mesh_path *mpath)
322 {
323 	struct mesh_table *tbl;
324 	int err;
325 
326 	rcu_read_lock();
327 	tbl = mpath->sdata->u.mesh.mesh_paths;
328 
329 	spin_lock_bh(&mpath->state_lock);
330 	if (mpath->is_gate) {
331 		err = -EEXIST;
332 		spin_unlock_bh(&mpath->state_lock);
333 		goto err_rcu;
334 	}
335 	mpath->is_gate = true;
336 	mpath->sdata->u.mesh.num_gates++;
337 
338 	spin_lock(&tbl->gates_lock);
339 	hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
340 	spin_unlock(&tbl->gates_lock);
341 
342 	spin_unlock_bh(&mpath->state_lock);
343 
344 	mpath_dbg(mpath->sdata,
345 		  "Mesh path: Recorded new gate: %pM. %d known gates\n",
346 		  mpath->dst, mpath->sdata->u.mesh.num_gates);
347 	err = 0;
348 err_rcu:
349 	rcu_read_unlock();
350 	return err;
351 }
352 
353 /**
354  * mesh_gate_del - remove a mesh gate from the list of known gates
355  * @tbl: table which holds our list of known gates
356  * @mpath: gate mpath
357  */
mesh_gate_del(struct mesh_table * tbl,struct mesh_path * mpath)358 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
359 {
360 	lockdep_assert_held(&mpath->state_lock);
361 	if (!mpath->is_gate)
362 		return;
363 
364 	mpath->is_gate = false;
365 	spin_lock_bh(&tbl->gates_lock);
366 	hlist_del_rcu(&mpath->gate_list);
367 	mpath->sdata->u.mesh.num_gates--;
368 	spin_unlock_bh(&tbl->gates_lock);
369 
370 	mpath_dbg(mpath->sdata,
371 		  "Mesh path: Deleted gate: %pM. %d known gates\n",
372 		  mpath->dst, mpath->sdata->u.mesh.num_gates);
373 }
374 
375 /**
376  * mesh_gate_num - number of gates known to this interface
377  * @sdata: subif data
378  */
mesh_gate_num(struct ieee80211_sub_if_data * sdata)379 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
380 {
381 	return sdata->u.mesh.num_gates;
382 }
383 
384 static
mesh_path_new(struct ieee80211_sub_if_data * sdata,const u8 * dst,gfp_t gfp_flags)385 struct mesh_path *mesh_path_new(struct ieee80211_sub_if_data *sdata,
386 				const u8 *dst, gfp_t gfp_flags)
387 {
388 	struct mesh_path *new_mpath;
389 
390 	new_mpath = kzalloc(sizeof(struct mesh_path), gfp_flags);
391 	if (!new_mpath)
392 		return NULL;
393 
394 	memcpy(new_mpath->dst, dst, ETH_ALEN);
395 	eth_broadcast_addr(new_mpath->rann_snd_addr);
396 	new_mpath->is_root = false;
397 	new_mpath->sdata = sdata;
398 	new_mpath->flags = 0;
399 	skb_queue_head_init(&new_mpath->frame_queue);
400 	new_mpath->timer.data = (unsigned long) new_mpath;
401 	new_mpath->timer.function = mesh_path_timer;
402 	new_mpath->exp_time = jiffies;
403 	spin_lock_init(&new_mpath->state_lock);
404 	init_timer(&new_mpath->timer);
405 
406 	return new_mpath;
407 }
408 
409 /**
410  * mesh_path_add - allocate and add a new path to the mesh path table
411  * @dst: destination address of the path (ETH_ALEN length)
412  * @sdata: local subif
413  *
414  * Returns: 0 on success
415  *
416  * State: the initial state of the new path is set to 0
417  */
mesh_path_add(struct ieee80211_sub_if_data * sdata,const u8 * dst)418 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
419 				const u8 *dst)
420 {
421 	struct mesh_table *tbl;
422 	struct mesh_path *mpath, *new_mpath;
423 	int ret;
424 
425 	if (ether_addr_equal(dst, sdata->vif.addr))
426 		/* never add ourselves as neighbours */
427 		return ERR_PTR(-ENOTSUPP);
428 
429 	if (is_multicast_ether_addr(dst))
430 		return ERR_PTR(-ENOTSUPP);
431 
432 	if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
433 		return ERR_PTR(-ENOSPC);
434 
435 	new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
436 	if (!new_mpath)
437 		return ERR_PTR(-ENOMEM);
438 
439 	tbl = sdata->u.mesh.mesh_paths;
440 	do {
441 		ret = rhashtable_lookup_insert_fast(&tbl->rhead,
442 						    &new_mpath->rhash,
443 						    mesh_rht_params);
444 
445 		if (ret == -EEXIST)
446 			mpath = rhashtable_lookup_fast(&tbl->rhead,
447 						       dst,
448 						       mesh_rht_params);
449 
450 	} while (unlikely(ret == -EEXIST && !mpath));
451 
452 	if (ret && ret != -EEXIST)
453 		return ERR_PTR(ret);
454 
455 	/* At this point either new_mpath was added, or we found a
456 	 * matching entry already in the table; in the latter case
457 	 * free the unnecessary new entry.
458 	 */
459 	if (ret == -EEXIST) {
460 		kfree(new_mpath);
461 		new_mpath = mpath;
462 	}
463 	sdata->u.mesh.mesh_paths_generation++;
464 	return new_mpath;
465 }
466 
mpp_path_add(struct ieee80211_sub_if_data * sdata,const u8 * dst,const u8 * mpp)467 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
468 		 const u8 *dst, const u8 *mpp)
469 {
470 	struct mesh_table *tbl;
471 	struct mesh_path *new_mpath;
472 	int ret;
473 
474 	if (ether_addr_equal(dst, sdata->vif.addr))
475 		/* never add ourselves as neighbours */
476 		return -ENOTSUPP;
477 
478 	if (is_multicast_ether_addr(dst))
479 		return -ENOTSUPP;
480 
481 	new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
482 
483 	if (!new_mpath)
484 		return -ENOMEM;
485 
486 	memcpy(new_mpath->mpp, mpp, ETH_ALEN);
487 	tbl = sdata->u.mesh.mpp_paths;
488 	ret = rhashtable_lookup_insert_fast(&tbl->rhead,
489 					    &new_mpath->rhash,
490 					    mesh_rht_params);
491 
492 	sdata->u.mesh.mpp_paths_generation++;
493 	return ret;
494 }
495 
496 
497 /**
498  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
499  *
500  * @sta: broken peer link
501  *
502  * This function must be called from the rate control algorithm if enough
503  * delivery errors suggest that a peer link is no longer usable.
504  */
mesh_plink_broken(struct sta_info * sta)505 void mesh_plink_broken(struct sta_info *sta)
506 {
507 	struct ieee80211_sub_if_data *sdata = sta->sdata;
508 	struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
509 	static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
510 	struct mesh_path *mpath;
511 	struct rhashtable_iter iter;
512 	int ret;
513 
514 	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
515 	if (ret)
516 		return;
517 
518 	ret = rhashtable_walk_start(&iter);
519 	if (ret && ret != -EAGAIN)
520 		goto out;
521 
522 	while ((mpath = rhashtable_walk_next(&iter))) {
523 		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
524 			continue;
525 		if (IS_ERR(mpath))
526 			break;
527 		if (rcu_access_pointer(mpath->next_hop) == sta &&
528 		    mpath->flags & MESH_PATH_ACTIVE &&
529 		    !(mpath->flags & MESH_PATH_FIXED)) {
530 			spin_lock_bh(&mpath->state_lock);
531 			mpath->flags &= ~MESH_PATH_ACTIVE;
532 			++mpath->sn;
533 			spin_unlock_bh(&mpath->state_lock);
534 			mesh_path_error_tx(sdata,
535 				sdata->u.mesh.mshcfg.element_ttl,
536 				mpath->dst, mpath->sn,
537 				WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
538 		}
539 	}
540 out:
541 	rhashtable_walk_stop(&iter);
542 	rhashtable_walk_exit(&iter);
543 }
544 
mesh_path_free_rcu(struct mesh_table * tbl,struct mesh_path * mpath)545 static void mesh_path_free_rcu(struct mesh_table *tbl,
546 			       struct mesh_path *mpath)
547 {
548 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
549 
550 	spin_lock_bh(&mpath->state_lock);
551 	mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
552 	mesh_gate_del(tbl, mpath);
553 	spin_unlock_bh(&mpath->state_lock);
554 	del_timer_sync(&mpath->timer);
555 	atomic_dec(&sdata->u.mesh.mpaths);
556 	atomic_dec(&tbl->entries);
557 	kfree_rcu(mpath, rcu);
558 }
559 
__mesh_path_del(struct mesh_table * tbl,struct mesh_path * mpath)560 static void __mesh_path_del(struct mesh_table *tbl, struct mesh_path *mpath)
561 {
562 	rhashtable_remove_fast(&tbl->rhead, &mpath->rhash, mesh_rht_params);
563 	mesh_path_free_rcu(tbl, mpath);
564 }
565 
566 /**
567  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
568  *
569  * @sta: mesh peer to match
570  *
571  * RCU notes: this function is called when a mesh plink transitions from
572  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
573  * allows path creation. This will happen before the sta can be freed (because
574  * sta_info_destroy() calls this) so any reader in a rcu read block will be
575  * protected against the plink disappearing.
576  */
mesh_path_flush_by_nexthop(struct sta_info * sta)577 void mesh_path_flush_by_nexthop(struct sta_info *sta)
578 {
579 	struct ieee80211_sub_if_data *sdata = sta->sdata;
580 	struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
581 	struct mesh_path *mpath;
582 	struct rhashtable_iter iter;
583 	int ret;
584 
585 	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
586 	if (ret)
587 		return;
588 
589 	ret = rhashtable_walk_start(&iter);
590 	if (ret && ret != -EAGAIN)
591 		goto out;
592 
593 	while ((mpath = rhashtable_walk_next(&iter))) {
594 		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
595 			continue;
596 		if (IS_ERR(mpath))
597 			break;
598 
599 		if (rcu_access_pointer(mpath->next_hop) == sta)
600 			__mesh_path_del(tbl, mpath);
601 	}
602 out:
603 	rhashtable_walk_stop(&iter);
604 	rhashtable_walk_exit(&iter);
605 }
606 
mpp_flush_by_proxy(struct ieee80211_sub_if_data * sdata,const u8 * proxy)607 static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
608 			       const u8 *proxy)
609 {
610 	struct mesh_table *tbl = sdata->u.mesh.mpp_paths;
611 	struct mesh_path *mpath;
612 	struct rhashtable_iter iter;
613 	int ret;
614 
615 	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
616 	if (ret)
617 		return;
618 
619 	ret = rhashtable_walk_start(&iter);
620 	if (ret && ret != -EAGAIN)
621 		goto out;
622 
623 	while ((mpath = rhashtable_walk_next(&iter))) {
624 		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
625 			continue;
626 		if (IS_ERR(mpath))
627 			break;
628 
629 		if (ether_addr_equal(mpath->mpp, proxy))
630 			__mesh_path_del(tbl, mpath);
631 	}
632 out:
633 	rhashtable_walk_stop(&iter);
634 	rhashtable_walk_exit(&iter);
635 }
636 
table_flush_by_iface(struct mesh_table * tbl)637 static void table_flush_by_iface(struct mesh_table *tbl)
638 {
639 	struct mesh_path *mpath;
640 	struct rhashtable_iter iter;
641 	int ret;
642 
643 	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
644 	if (ret)
645 		return;
646 
647 	ret = rhashtable_walk_start(&iter);
648 	if (ret && ret != -EAGAIN)
649 		goto out;
650 
651 	while ((mpath = rhashtable_walk_next(&iter))) {
652 		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
653 			continue;
654 		if (IS_ERR(mpath))
655 			break;
656 		__mesh_path_del(tbl, mpath);
657 	}
658 out:
659 	rhashtable_walk_stop(&iter);
660 	rhashtable_walk_exit(&iter);
661 }
662 
663 /**
664  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
665  *
666  * This function deletes both mesh paths as well as mesh portal paths.
667  *
668  * @sdata: interface data to match
669  *
670  */
mesh_path_flush_by_iface(struct ieee80211_sub_if_data * sdata)671 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
672 {
673 	table_flush_by_iface(sdata->u.mesh.mesh_paths);
674 	table_flush_by_iface(sdata->u.mesh.mpp_paths);
675 }
676 
677 /**
678  * table_path_del - delete a path from the mesh or mpp table
679  *
680  * @tbl: mesh or mpp path table
681  * @sdata: local subif
682  * @addr: dst address (ETH_ALEN length)
683  *
684  * Returns: 0 if successful
685  */
table_path_del(struct mesh_table * tbl,struct ieee80211_sub_if_data * sdata,const u8 * addr)686 static int table_path_del(struct mesh_table *tbl,
687 			  struct ieee80211_sub_if_data *sdata,
688 			  const u8 *addr)
689 {
690 	struct mesh_path *mpath;
691 
692 	rcu_read_lock();
693 	mpath = rhashtable_lookup_fast(&tbl->rhead, addr, mesh_rht_params);
694 	if (!mpath) {
695 		rcu_read_unlock();
696 		return -ENXIO;
697 	}
698 
699 	__mesh_path_del(tbl, mpath);
700 	rcu_read_unlock();
701 	return 0;
702 }
703 
704 
705 /**
706  * mesh_path_del - delete a mesh path from the table
707  *
708  * @addr: dst address (ETH_ALEN length)
709  * @sdata: local subif
710  *
711  * Returns: 0 if successful
712  */
mesh_path_del(struct ieee80211_sub_if_data * sdata,const u8 * addr)713 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
714 {
715 	int err;
716 
717 	/* flush relevant mpp entries first */
718 	mpp_flush_by_proxy(sdata, addr);
719 
720 	err = table_path_del(sdata->u.mesh.mesh_paths, sdata, addr);
721 	sdata->u.mesh.mesh_paths_generation++;
722 	return err;
723 }
724 
725 /**
726  * mesh_path_tx_pending - sends pending frames in a mesh path queue
727  *
728  * @mpath: mesh path to activate
729  *
730  * Locking: the state_lock of the mpath structure must NOT be held when calling
731  * this function.
732  */
mesh_path_tx_pending(struct mesh_path * mpath)733 void mesh_path_tx_pending(struct mesh_path *mpath)
734 {
735 	if (mpath->flags & MESH_PATH_ACTIVE)
736 		ieee80211_add_pending_skbs(mpath->sdata->local,
737 				&mpath->frame_queue);
738 }
739 
740 /**
741  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
742  *
743  * @mpath: mesh path whose queue will be emptied
744  *
745  * If there is only one gate, the frames are transferred from the failed mpath
746  * queue to that gate's queue.  If there are more than one gates, the frames
747  * are copied from each gate to the next.  After frames are copied, the
748  * mpath queues are emptied onto the transmission queue.
749  */
mesh_path_send_to_gates(struct mesh_path * mpath)750 int mesh_path_send_to_gates(struct mesh_path *mpath)
751 {
752 	struct ieee80211_sub_if_data *sdata = mpath->sdata;
753 	struct mesh_table *tbl;
754 	struct mesh_path *from_mpath = mpath;
755 	struct mesh_path *gate;
756 	bool copy = false;
757 
758 	tbl = sdata->u.mesh.mesh_paths;
759 
760 	rcu_read_lock();
761 	hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
762 		if (gate->flags & MESH_PATH_ACTIVE) {
763 			mpath_dbg(sdata, "Forwarding to %pM\n", gate->dst);
764 			mesh_path_move_to_queue(gate, from_mpath, copy);
765 			from_mpath = gate;
766 			copy = true;
767 		} else {
768 			mpath_dbg(sdata,
769 				  "Not forwarding to %pM (flags %#x)\n",
770 				  gate->dst, gate->flags);
771 		}
772 	}
773 
774 	hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
775 		mpath_dbg(sdata, "Sending to %pM\n", gate->dst);
776 		mesh_path_tx_pending(gate);
777 	}
778 	rcu_read_unlock();
779 
780 	return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
781 }
782 
783 /**
784  * mesh_path_discard_frame - discard a frame whose path could not be resolved
785  *
786  * @skb: frame to discard
787  * @sdata: network subif the frame was to be sent through
788  *
789  * Locking: the function must me called within a rcu_read_lock region
790  */
mesh_path_discard_frame(struct ieee80211_sub_if_data * sdata,struct sk_buff * skb)791 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
792 			     struct sk_buff *skb)
793 {
794 	kfree_skb(skb);
795 	sdata->u.mesh.mshstats.dropped_frames_no_route++;
796 }
797 
798 /**
799  * mesh_path_flush_pending - free the pending queue of a mesh path
800  *
801  * @mpath: mesh path whose queue has to be freed
802  *
803  * Locking: the function must me called within a rcu_read_lock region
804  */
mesh_path_flush_pending(struct mesh_path * mpath)805 void mesh_path_flush_pending(struct mesh_path *mpath)
806 {
807 	struct sk_buff *skb;
808 
809 	while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
810 		mesh_path_discard_frame(mpath->sdata, skb);
811 }
812 
813 /**
814  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
815  *
816  * @mpath: the mesh path to modify
817  * @next_hop: the next hop to force
818  *
819  * Locking: this function must be called holding mpath->state_lock
820  */
mesh_path_fix_nexthop(struct mesh_path * mpath,struct sta_info * next_hop)821 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
822 {
823 	spin_lock_bh(&mpath->state_lock);
824 	mesh_path_assign_nexthop(mpath, next_hop);
825 	mpath->sn = 0xffff;
826 	mpath->metric = 0;
827 	mpath->hop_count = 0;
828 	mpath->exp_time = 0;
829 	mpath->flags = MESH_PATH_FIXED | MESH_PATH_SN_VALID;
830 	mesh_path_activate(mpath);
831 	spin_unlock_bh(&mpath->state_lock);
832 	mesh_path_tx_pending(mpath);
833 }
834 
mesh_pathtbl_init(struct ieee80211_sub_if_data * sdata)835 int mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
836 {
837 	struct mesh_table *tbl_path, *tbl_mpp;
838 	int ret;
839 
840 	tbl_path = mesh_table_alloc();
841 	if (!tbl_path)
842 		return -ENOMEM;
843 
844 	tbl_mpp = mesh_table_alloc();
845 	if (!tbl_mpp) {
846 		ret = -ENOMEM;
847 		goto free_path;
848 	}
849 
850 	rhashtable_init(&tbl_path->rhead, &mesh_rht_params);
851 	rhashtable_init(&tbl_mpp->rhead, &mesh_rht_params);
852 
853 	sdata->u.mesh.mesh_paths = tbl_path;
854 	sdata->u.mesh.mpp_paths = tbl_mpp;
855 
856 	return 0;
857 
858 free_path:
859 	mesh_table_free(tbl_path);
860 	return ret;
861 }
862 
863 static
mesh_path_tbl_expire(struct ieee80211_sub_if_data * sdata,struct mesh_table * tbl)864 void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
865 			  struct mesh_table *tbl)
866 {
867 	struct mesh_path *mpath;
868 	struct rhashtable_iter iter;
869 	int ret;
870 
871 	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_KERNEL);
872 	if (ret)
873 		return;
874 
875 	ret = rhashtable_walk_start(&iter);
876 	if (ret && ret != -EAGAIN)
877 		goto out;
878 
879 	while ((mpath = rhashtable_walk_next(&iter))) {
880 		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
881 			continue;
882 		if (IS_ERR(mpath))
883 			break;
884 		if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
885 		    (!(mpath->flags & MESH_PATH_FIXED)) &&
886 		     time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
887 			__mesh_path_del(tbl, mpath);
888 	}
889 out:
890 	rhashtable_walk_stop(&iter);
891 	rhashtable_walk_exit(&iter);
892 }
893 
mesh_path_expire(struct ieee80211_sub_if_data * sdata)894 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
895 {
896 	mesh_path_tbl_expire(sdata, sdata->u.mesh.mesh_paths);
897 	mesh_path_tbl_expire(sdata, sdata->u.mesh.mpp_paths);
898 }
899 
mesh_pathtbl_unregister(struct ieee80211_sub_if_data * sdata)900 void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
901 {
902 	mesh_table_free(sdata->u.mesh.mesh_paths);
903 	mesh_table_free(sdata->u.mesh.mpp_paths);
904 }
905