summaryrefslogtreecommitdiffstats
path: root/net/mac80211/mesh_pathtbl.c
blob: 97269caafecd7b52e644e9bb645d305fdfb67196 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
/*
 * Copyright (c) 2008, 2009 open80211s Ltd.
 * Author:     Luis Carlos Cobo <luisca@cozybit.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/etherdevice.h>
#include <linux/list.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <net/mac80211.h>
#include "wme.h"
#include "ieee80211_i.h"
#include "mesh.h"

static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);

static u32 mesh_table_hash(const void *addr, u32 len, u32 seed)
{
	/* Use last four bytes of hw addr as hash index */
	return jhash_1word(*(u32 *)(addr+2), seed);
}

static const struct rhashtable_params mesh_rht_params = {
	.nelem_hint = 2,
	.automatic_shrinking = true,
	.key_len = ETH_ALEN,
	.key_offset = offsetof(struct mesh_path, dst),
	.head_offset = offsetof(struct mesh_path, rhash),
	.hashfn = mesh_table_hash,
};

static inline bool mpath_expired(struct mesh_path *mpath)
{
	return (mpath->flags & MESH_PATH_ACTIVE) &&
	       time_after(jiffies, mpath->exp_time) &&
	       !(mpath->flags & MESH_PATH_FIXED);
}

static void mesh_path_rht_free(void *ptr, void *tblptr)
{
	struct mesh_path *mpath = ptr;
	struct mesh_table *tbl = tblptr;

	mesh_path_free_rcu(tbl, mpath);
}

static struct mesh_table *mesh_table_alloc(void)
{
	struct mesh_table *newtbl;

	newtbl = kmalloc(sizeof(struct mesh_table), GFP_ATOMIC);
	if (!newtbl)
		return NULL;

	INIT_HLIST_HEAD(&newtbl->known_gates);
	atomic_set(&newtbl->entries,  0);
	spin_lock_init(&newtbl->gates_lock);

	return newtbl;
}

static void mesh_table_free(struct mesh_table *tbl)
{
	rhashtable_free_and_destroy(&tbl->rhead,
				    mesh_path_rht_free, tbl);
	kfree(tbl);
}

/**
 *
 * mesh_path_assign_nexthop - update mesh path next hop
 *
 * @mpath: mesh path to update
 * @sta: next hop to assign
 *
 * Locking: mpath->state_lock must be held when calling this function
 */
void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
{
	struct sk_buff *skb;
	struct ieee80211_hdr *hdr;
	unsigned long flags;

	rcu_assign_pointer(mpath->next_hop, sta);

	spin_lock_irqsave(&mpath->frame_queue.lock, flags);
	skb_queue_walk(&mpath->frame_queue, skb) {
		hdr = (struct ieee80211_hdr *) skb->data;
		memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
		memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
		ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
	}

	spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
}

static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
			     struct mesh_path *gate_mpath)
{
	struct ieee80211_hdr *hdr;
	struct ieee80211s_hdr *mshdr;
	int mesh_hdrlen, hdrlen;
	char *next_hop;

	hdr = (struct ieee80211_hdr *) skb->data;
	hdrlen = ieee80211_hdrlen(hdr->frame_control);
	mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);

	if (!(mshdr->flags & MESH_FLAGS_AE)) {
		/* size of the fixed part of the mesh header */
		mesh_hdrlen = 6;

		/* make room for the two extended addresses */
		skb_push(skb, 2 * ETH_ALEN);
		memmove(skb->data, hdr, hdrlen + mesh_hdrlen);

		hdr = (struct ieee80211_hdr *) skb->data;

		/* we preserve the previous mesh header and only add
		 * the new addreses */
		mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
		mshdr->flags = MESH_FLAGS_AE_A5_A6;
		memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
		memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
	}

	/* update next hop */
	hdr = (struct ieee80211_hdr *) skb->data;
	rcu_read_lock();
	next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
	memcpy(hdr->addr1, next_hop, ETH_ALEN);
	rcu_read_unlock();
	memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
	memcpy(hdr->addr3, dst_addr, ETH_ALEN);
}

/**
 *
 * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
 *
 * This function is used to transfer or copy frames from an unresolved mpath to
 * a gate mpath.  The function also adds the Address Extension field and
 * updates the next hop.
 *
 * If a frame already has an Address Extension field, only the next hop and
 * destination addresses are updated.
 *
 * The gate mpath must be an active mpath with a valid mpath->next_hop.
 *
 * @mpath: An active mpath the frames will be sent to (i.e. the gate)
 * @from_mpath: The failed mpath
 * @copy: When true, copy all the frames to the new mpath queue.  When false,
 * move them.
 */
static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
				    struct mesh_path *from_mpath,
				    bool copy)
{
	struct sk_buff *skb, *fskb, *tmp;
	struct sk_buff_head failq;
	unsigned long flags;

	if (WARN_ON(gate_mpath == from_mpath))
		return;
	if (WARN_ON(!gate_mpath->next_hop))
		return;

	__skb_queue_head_init(&failq);

	spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
	skb_queue_splice_init(&from_mpath->frame_queue, &failq);
	spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);

	skb_queue_walk_safe(&failq, fskb, tmp) {
		if (skb_queue_len(&gate_mpath->frame_queue) >=
				  MESH_FRAME_QUEUE_LEN) {
			mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
			break;
		}

		skb = skb_copy(fskb, GFP_ATOMIC);
		if (WARN_ON(!skb))
			break;

		prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
		skb_queue_tail(&gate_mpath->frame_queue, skb);

		if (copy)
			continue;

		__skb_unlink(fskb, &failq);
		kfree_skb(fskb);
	}

	mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
		  gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));

	if (!copy)
		return;

	spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
	skb_queue_splice(&failq, &from_mpath->frame_queue);
	spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
}


static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
				      struct ieee80211_sub_if_data *sdata)
{
	struct mesh_path *mpath;

	mpath = rhashtable_lookup_fast(&tbl->rhead, dst, mesh_rht_params);

	if (mpath && mpath_expired(mpath)) {
		spin_lock_bh(&mpath->state_lock);
		mpath->flags &= ~MESH_PATH_ACTIVE;
		spin_unlock_bh(&mpath->state_lock);
	}
	return mpath;
}

/**
 * mesh_path_lookup - look up a path in the mesh path table
 * @sdata: local subif
 * @dst: hardware address (ETH_ALEN length) of destination
 *
 * Returns: pointer to the mesh path structure, or NULL if not found
 *
 * Locking: must be called within a read rcu section.
 */
struct mesh_path *
mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
{
	return mpath_lookup(sdata->u.mesh.mesh_paths, dst, sdata);
}

struct mesh_path *
mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
{
	return mpath_lookup(sdata->u.mesh.mpp_paths, dst, sdata);
}

static struct mesh_path *
__mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
{
	int i = 0, ret;
	struct mesh_path *mpath = NULL;
	struct rhashtable_iter iter;

	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
	if (ret)
		return NULL;

	ret = rhashtable_walk_start(&iter);
	if (ret && ret != -EAGAIN)
		goto err;

	while ((mpath = rhashtable_walk_next(&iter))) {
		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
			continue;
		if (IS_ERR(mpath))
			break;
		if (i++ == idx)
			break;
	}
err:
	rhashtable_walk_stop(&iter);
	rhashtable_walk_exit(&iter);

	if (IS_ERR(mpath) || !mpath)
		return NULL;

	if (mpath_expired(mpath)) {
		spin_lock_bh(&mpath->state_lock);
		mpath->flags &= ~MESH_PATH_ACTIVE;
		spin_unlock_bh(&mpath->state_lock);
	}
	return mpath;
}

/**
 * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
 * @idx: index
 * @sdata: local subif, or NULL for all entries
 *
 * Returns: pointer to the mesh path structure, or NULL if not found.
 *
 * Locking: must be called within a read rcu section.
 */
struct mesh_path *
mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
{
	return __mesh_path_lookup_by_idx(sdata->u.mesh.mesh_paths, idx);
}

/**
 * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
 * @idx: index
 * @sdata: local subif, or NULL for all entries
 *
 * Returns: pointer to the proxy path structure, or NULL if not found.
 *
 * Locking: must be called within a read rcu section.
 */
struct mesh_path *
mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
{
	return __mesh_path_lookup_by_idx(sdata->u.mesh.mpp_paths, idx);
}

/**
 * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
 * @mpath: gate path to add to table
 */
int mesh_path_add_gate(struct mesh_path *mpath)
{
	struct mesh_table *tbl;
	int err;

	rcu_read_lock();
	tbl = mpath->sdata->u.mesh.mesh_paths;

	spin_lock_bh(&mpath->state_lock);
	if (mpath->is_gate) {
		err = -EEXIST;
		spin_unlock_bh(&mpath->state_lock);
		goto err_rcu;
	}
	mpath->is_gate = true;
	mpath->sdata->u.mesh.num_gates++;

	spin_lock(&tbl->gates_lock);
	hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
	spin_unlock(&tbl->gates_lock);

	spin_unlock_bh(&mpath->state_lock);

	mpath_dbg(mpath->sdata,
		  "Mesh path: Recorded new gate: %pM. %d known gates\n",
		  mpath->dst, mpath->sdata->u.mesh.num_gates);
	err = 0;
err_rcu:
	rcu_read_unlock();
	return err;
}

/**
 * mesh_gate_del - remove a mesh gate from the list of known gates
 * @tbl: table which holds our list of known gates
 * @mpath: gate mpath
 */
static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
{
	lockdep_assert_held(&mpath->state_lock);
	if (!mpath->is_gate)
		return;

	mpath->is_gate = false;
	spin_lock_bh(&tbl->gates_lock);
	hlist_del_rcu(&mpath->gate_list);
	mpath->sdata->u.mesh.num_gates--;
	spin_unlock_bh(&tbl->gates_lock);

	mpath_dbg(mpath->sdata,
		  "Mesh path: Deleted gate: %pM. %d known gates\n",
		  mpath->dst, mpath->sdata->u.mesh.num_gates);
}

/**
 * mesh_gate_num - number of gates known to this interface
 * @sdata: subif data
 */
int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
{
	return sdata->u.mesh.num_gates;
}

static
struct mesh_path *mesh_path_new(struct ieee80211_sub_if_data *sdata,
				const u8 *dst, gfp_t gfp_flags)
{
	struct mesh_path *new_mpath;

	new_mpath = kzalloc(sizeof(struct mesh_path), gfp_flags);
	if (!new_mpath)
		return NULL;

	memcpy(new_mpath->dst, dst, ETH_ALEN);
	eth_broadcast_addr(new_mpath->rann_snd_addr);
	new_mpath->is_root = false;
	new_mpath->sdata = sdata;
	new_mpath->flags = 0;
	skb_queue_head_init(&new_mpath->frame_queue);
	new_mpath->exp_time = jiffies;
	spin_lock_init(&new_mpath->state_lock);
	setup_timer(&new_mpath->timer, mesh_path_timer,
		    (unsigned long) new_mpath);

	return new_mpath;
}

/**
 * mesh_path_add - allocate and add a new path to the mesh path table
 * @dst: destination address of the path (ETH_ALEN length)
 * @sdata: local subif
 *
 * Returns: 0 on success
 *
 * State: the initial state of the new path is set to 0
 */
struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
				const u8 *dst)
{
	struct mesh_table *tbl;
	struct mesh_path *mpath, *new_mpath;
	int ret;

	if (ether_addr_equal(dst, sdata->vif.addr))
		/* never add ourselves as neighbours */
		return ERR_PTR(-ENOTSUPP);

	if (is_multicast_ether_addr(dst))
		return ERR_PTR(-ENOTSUPP);

	if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
		return ERR_PTR(-ENOSPC);

	new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
	if (!new_mpath)
		return ERR_PTR(-ENOMEM);

	tbl = sdata->u.mesh.mesh_paths;
	do {
		ret = rhashtable_lookup_insert_fast(&tbl->rhead,
						    &new_mpath->rhash,
						    mesh_rht_params);

		if (ret == -EEXIST)
			mpath = rhashtable_lookup_fast(&tbl->rhead,
						       dst,
						       mesh_rht_params);

	} while (unlikely(ret == -EEXIST && !mpath));

	if (ret && ret != -EEXIST)
		return ERR_PTR(ret);

	/* At this point either new_mpath was added, or we found a
	 * matching entry already in the table; in the latter case
	 * free the unnecessary new entry.
	 */
	if (ret == -EEXIST) {
		kfree(new_mpath);
		new_mpath = mpath;
	}
	sdata->u.mesh.mesh_paths_generation++;
	return new_mpath;
}

int mpp_path_add(struct ieee80211_sub_if_data *sdata,
		 const u8 *dst, const u8 *mpp)
{
	struct mesh_table *tbl;
	struct mesh_path *new_mpath;
	int ret;

	if (ether_addr_equal(dst, sdata->vif.addr))
		/* never add ourselves as neighbours */
		return -ENOTSUPP;

	if (is_multicast_ether_addr(dst))
		return -ENOTSUPP;

	new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);

	if (!new_mpath)
		return -ENOMEM;

	memcpy(new_mpath->mpp, mpp, ETH_ALEN);
	tbl = sdata->u.mesh.mpp_paths;
	ret = rhashtable_lookup_insert_fast(&tbl->rhead,
					    &new_mpath->rhash,
					    mesh_rht_params);

	sdata->u.mesh.mpp_paths_generation++;
	return ret;
}


/**
 * mesh_plink_broken - deactivates paths and sends perr when a link breaks
 *
 * @sta: broken peer link
 *
 * This function must be called from the rate control algorithm if enough
 * delivery errors suggest that a peer link is no longer usable.
 */
void mesh_plink_broken(struct sta_info *sta)
{
	struct ieee80211_sub_if_data *sdata = sta->sdata;
	struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
	static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
	struct mesh_path *mpath;
	struct rhashtable_iter iter;
	int ret;

	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
	if (ret)
		return;

	ret = rhashtable_walk_start(&iter);
	if (ret && ret != -EAGAIN)
		goto out;

	while ((mpath = rhashtable_walk_next(&iter))) {
		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
			continue;
		if (IS_ERR(mpath))
			break;
		if (rcu_access_pointer(mpath->next_hop) == sta &&
		    mpath->flags & MESH_PATH_ACTIVE &&
		    !(mpath->flags & MESH_PATH_FIXED)) {
			spin_lock_bh(&mpath->state_lock);
			mpath->flags &= ~MESH_PATH_ACTIVE;
			++mpath->sn;
			spin_unlock_bh(&mpath->state_lock);
			mesh_path_error_tx(sdata,
				sdata->u.mesh.mshcfg.element_ttl,
				mpath->dst, mpath->sn,
				WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
		}
	}
out:
	rhashtable_walk_stop(&iter);
	rhashtable_walk_exit(&iter);
}

static void mesh_path_free_rcu(struct mesh_table *tbl,
			       struct mesh_path *mpath)
{
	struct ieee80211_sub_if_data *sdata = mpath->sdata;

	spin_lock_bh(&mpath->state_lock);
	mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
	mesh_gate_del(tbl, mpath);
	spin_unlock_bh(&mpath->state_lock);
	del_timer_sync(&mpath->timer);
	atomic_dec(&sdata->u.mesh.mpaths);
	atomic_dec(&tbl->entries);
	kfree_rcu(mpath, rcu);
}

static void __mesh_path_del(struct mesh_table *tbl, struct mesh_path *mpath)
{
	rhashtable_remove_fast(&tbl->rhead, &mpath->rhash, mesh_rht_params);
	mesh_path_free_rcu(tbl, mpath);
}

/**
 * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
 *
 * @sta: mesh peer to match
 *
 * RCU notes: this function is called when a mesh plink transitions from
 * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
 * allows path creation. This will happen before the sta can be freed (because
 * sta_info_destroy() calls this) so any reader in a rcu read block will be
 * protected against the plink disappearing.
 */
void mesh_path_flush_by_nexthop(struct sta_info *sta)
{
	struct ieee80211_sub_if_data *sdata = sta->sdata;
	struct mesh_table *tbl = sdata->u.mesh.mesh_paths;
	struct mesh_path *mpath;
	struct rhashtable_iter iter;
	int ret;

	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
	if (ret)
		return;

	ret = rhashtable_walk_start(&iter);
	if (ret && ret != -EAGAIN)
		goto out;

	while ((mpath = rhashtable_walk_next(&iter))) {
		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
			continue;
		if (IS_ERR(mpath))
			break;

		if (rcu_access_pointer(mpath->next_hop) == sta)
			__mesh_path_del(tbl, mpath);
	}
out:
	rhashtable_walk_stop(&iter);
	rhashtable_walk_exit(&iter);
}

static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
			       const u8 *proxy)
{
	struct mesh_table *tbl = sdata->u.mesh.mpp_paths;
	struct mesh_path *mpath;
	struct rhashtable_iter iter;
	int ret;

	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
	if (ret)
		return;

	ret = rhashtable_walk_start(&iter);
	if (ret && ret != -EAGAIN)
		goto out;

	while ((mpath = rhashtable_walk_next(&iter))) {
		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
			continue;
		if (IS_ERR(mpath))
			break;

		if (ether_addr_equal(mpath->mpp, proxy))
			__mesh_path_del(tbl, mpath);
	}
out:
	rhashtable_walk_stop(&iter);
	rhashtable_walk_exit(&iter);
}

static void table_flush_by_iface(struct mesh_table *tbl)
{
	struct mesh_path *mpath;
	struct rhashtable_iter iter;
	int ret;

	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_ATOMIC);
	if (ret)
		return;

	ret = rhashtable_walk_start(&iter);
	if (ret && ret != -EAGAIN)
		goto out;

	while ((mpath = rhashtable_walk_next(&iter))) {
		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
			continue;
		if (IS_ERR(mpath))
			break;
		__mesh_path_del(tbl, mpath);
	}
out:
	rhashtable_walk_stop(&iter);
	rhashtable_walk_exit(&iter);
}

/**
 * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
 *
 * This function deletes both mesh paths as well as mesh portal paths.
 *
 * @sdata: interface data to match
 *
 */
void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
{
	table_flush_by_iface(sdata->u.mesh.mesh_paths);
	table_flush_by_iface(sdata->u.mesh.mpp_paths);
}

/**
 * table_path_del - delete a path from the mesh or mpp table
 *
 * @tbl: mesh or mpp path table
 * @sdata: local subif
 * @addr: dst address (ETH_ALEN length)
 *
 * Returns: 0 if successful
 */
static int table_path_del(struct mesh_table *tbl,
			  struct ieee80211_sub_if_data *sdata,
			  const u8 *addr)
{
	struct mesh_path *mpath;

	rcu_read_lock();
	mpath = rhashtable_lookup_fast(&tbl->rhead, addr, mesh_rht_params);
	if (!mpath) {
		rcu_read_unlock();
		return -ENXIO;
	}

	__mesh_path_del(tbl, mpath);
	rcu_read_unlock();
	return 0;
}


/**
 * mesh_path_del - delete a mesh path from the table
 *
 * @addr: dst address (ETH_ALEN length)
 * @sdata: local subif
 *
 * Returns: 0 if successful
 */
int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
{
	int err;

	/* flush relevant mpp entries first */
	mpp_flush_by_proxy(sdata, addr);

	err = table_path_del(sdata->u.mesh.mesh_paths, sdata, addr);
	sdata->u.mesh.mesh_paths_generation++;
	return err;
}

/**
 * mesh_path_tx_pending - sends pending frames in a mesh path queue
 *
 * @mpath: mesh path to activate
 *
 * Locking: the state_lock of the mpath structure must NOT be held when calling
 * this function.
 */
void mesh_path_tx_pending(struct mesh_path *mpath)
{
	if (mpath->flags & MESH_PATH_ACTIVE)
		ieee80211_add_pending_skbs(mpath->sdata->local,
				&mpath->frame_queue);
}

/**
 * mesh_path_send_to_gates - sends pending frames to all known mesh gates
 *
 * @mpath: mesh path whose queue will be emptied
 *
 * If there is only one gate, the frames are transferred from the failed mpath
 * queue to that gate's queue.  If there are more than one gates, the frames
 * are copied from each gate to the next.  After frames are copied, the
 * mpath queues are emptied onto the transmission queue.
 */
int mesh_path_send_to_gates(struct mesh_path *mpath)
{
	struct ieee80211_sub_if_data *sdata = mpath->sdata;
	struct mesh_table *tbl;
	struct mesh_path *from_mpath = mpath;
	struct mesh_path *gate;
	bool copy = false;

	tbl = sdata->u.mesh.mesh_paths;

	rcu_read_lock();
	hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
		if (gate->flags & MESH_PATH_ACTIVE) {
			mpath_dbg(sdata, "Forwarding to %pM\n", gate->dst);
			mesh_path_move_to_queue(gate, from_mpath, copy);
			from_mpath = gate;
			copy = true;
		} else {
			mpath_dbg(sdata,
				  "Not forwarding to %pM (flags %#x)\n",
				  gate->dst, gate->flags);
		}
	}

	hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
		mpath_dbg(sdata, "Sending to %pM\n", gate->dst);
		mesh_path_tx_pending(gate);
	}
	rcu_read_unlock();

	return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
}

/**
 * mesh_path_discard_frame - discard a frame whose path could not be resolved
 *
 * @skb: frame to discard
 * @sdata: network subif the frame was to be sent through
 *
 * Locking: the function must me called within a rcu_read_lock region
 */
void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
			     struct sk_buff *skb)
{
	kfree_skb(skb);
	sdata->u.mesh.mshstats.dropped_frames_no_route++;
}

/**
 * mesh_path_flush_pending - free the pending queue of a mesh path
 *
 * @mpath: mesh path whose queue has to be freed
 *
 * Locking: the function must me called within a rcu_read_lock region
 */
void mesh_path_flush_pending(struct mesh_path *mpath)
{
	struct sk_buff *skb;

	while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
		mesh_path_discard_frame(mpath->sdata, skb);
}

/**
 * mesh_path_fix_nexthop - force a specific next hop for a mesh path
 *
 * @mpath: the mesh path to modify
 * @next_hop: the next hop to force
 *
 * Locking: this function must be called holding mpath->state_lock
 */
void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
{
	spin_lock_bh(&mpath->state_lock);
	mesh_path_assign_nexthop(mpath, next_hop);
	mpath->sn = 0xffff;
	mpath->metric = 0;
	mpath->hop_count = 0;
	mpath->exp_time = 0;
	mpath->flags = MESH_PATH_FIXED | MESH_PATH_SN_VALID;
	mesh_path_activate(mpath);
	spin_unlock_bh(&mpath->state_lock);
	ewma_mesh_fail_avg_init(&next_hop->mesh->fail_avg);
	/* init it at a low value - 0 start is tricky */
	ewma_mesh_fail_avg_add(&next_hop->mesh->fail_avg, 1);
	mesh_path_tx_pending(mpath);
}

int mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
{
	struct mesh_table *tbl_path, *tbl_mpp;
	int ret;

	tbl_path = mesh_table_alloc();
	if (!tbl_path)
		return -ENOMEM;

	tbl_mpp = mesh_table_alloc();
	if (!tbl_mpp) {
		ret = -ENOMEM;
		goto free_path;
	}

	rhashtable_init(&tbl_path->rhead, &mesh_rht_params);
	rhashtable_init(&tbl_mpp->rhead, &mesh_rht_params);

	sdata->u.mesh.mesh_paths = tbl_path;
	sdata->u.mesh.mpp_paths = tbl_mpp;

	return 0;

free_path:
	mesh_table_free(tbl_path);
	return ret;
}

static
void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
			  struct mesh_table *tbl)
{
	struct mesh_path *mpath;
	struct rhashtable_iter iter;
	int ret;

	ret = rhashtable_walk_init(&tbl->rhead, &iter, GFP_KERNEL);
	if (ret)
		return;

	ret = rhashtable_walk_start(&iter);
	if (ret && ret != -EAGAIN)
		goto out;

	while ((mpath = rhashtable_walk_next(&iter))) {
		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
			continue;
		if (IS_ERR(mpath))
			break;
		if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
		    (!(mpath->flags & MESH_PATH_FIXED)) &&
		     time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
			__mesh_path_del(tbl, mpath);
	}
out:
	rhashtable_walk_stop(&iter);
	rhashtable_walk_exit(&iter);
}

void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
{
	mesh_path_tbl_expire(sdata, sdata->u.mesh.mesh_paths);
	mesh_path_tbl_expire(sdata, sdata->u.mesh.mpp_paths);
}

void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
{
	mesh_table_free(sdata->u.mesh.mesh_paths);
	mesh_table_free(sdata->u.mesh.mpp_paths);
}
OpenPOWER on IntegriCloud