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