aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/uwb/wlp/wss-lc.c
blob: 90accdd54c07e14877e5018d2491b15b77cfd9e5 (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
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
/*
 * WiMedia Logical Link Control Protocol (WLP)
 *
 * Copyright (C) 2007 Intel Corporation
 * Reinette Chatre <reinette.chatre@intel.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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 *
 * Implementation of the WLP association protocol.
 *
 * FIXME: Docs
 *
 * A UWB network interface will configure a WSS through wlp_wss_setup() after
 * the interface has been assigned a MAC address, typically after
 * "ifconfig" has been called. When the interface goes down it should call
 * wlp_wss_remove().
 *
 * When the WSS is ready for use the user interacts via sysfs to create,
 * discover, and activate WSS.
 *
 * wlp_wss_enroll_activate()
 *
 * wlp_wss_create_activate()
 * 	wlp_wss_set_wssid_hash()
 * 		wlp_wss_comp_wssid_hash()
 * 	wlp_wss_sel_bcast_addr()
 * 	wlp_wss_sysfs_add()
 *
 * Called when no more references to WSS exist:
 * 	wlp_wss_release()
 * 		wlp_wss_reset()
 */
#include <linux/etherdevice.h> /* for is_valid_ether_addr */
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/wlp.h>

#include "wlp-internal.h"

size_t wlp_wss_key_print(char *buf, size_t bufsize, u8 *key)
{
	size_t result;

	result = scnprintf(buf, bufsize,
			  "%02x %02x %02x %02x %02x %02x "
			  "%02x %02x %02x %02x %02x %02x "
			  "%02x %02x %02x %02x",
			  key[0], key[1], key[2], key[3],
			  key[4], key[5], key[6], key[7],
			  key[8], key[9], key[10], key[11],
			  key[12], key[13], key[14], key[15]);
	return result;
}

/**
 * Compute WSSID hash
 * WLP Draft 0.99 [7.2.1]
 *
 * The WSSID hash for a WSSID is the result of an octet-wise exclusive-OR
 * of all octets in the WSSID.
 */
static
u8 wlp_wss_comp_wssid_hash(struct wlp_uuid *wssid)
{
	return wssid->data[0]  ^ wssid->data[1]  ^ wssid->data[2]
	       ^ wssid->data[3]  ^ wssid->data[4]  ^ wssid->data[5]
	       ^ wssid->data[6]  ^ wssid->data[7]  ^ wssid->data[8]
	       ^ wssid->data[9]  ^ wssid->data[10] ^ wssid->data[11]
	       ^ wssid->data[12] ^ wssid->data[13] ^ wssid->data[14]
	       ^ wssid->data[15];
}

/**
 * Select a multicast EUI-48 for the WSS broadcast address.
 * WLP Draft 0.99 [7.2.1]
 *
 * Selected based on the WiMedia Alliance OUI, 00-13-88, within the WLP
 * range, [01-13-88-00-01-00, 01-13-88-00-01-FF] inclusive.
 *
 * This address is currently hardcoded.
 * FIXME?
 */
static
struct uwb_mac_addr wlp_wss_sel_bcast_addr(struct wlp_wss *wss)
{
	struct uwb_mac_addr bcast = {
		.data = { 0x01, 0x13, 0x88, 0x00, 0x01, 0x00 }
	};
	return bcast;
}

/**
 * Clear the contents of the WSS structure - all except kobj, mutex, virtual
 *
 * We do not want to reinitialize - the internal kobj should not change as
 * it still points to the parent received during setup. The mutex should
 * remain also. We thus just reset values individually.
 * The virutal address assigned to WSS will remain the same for the
 * lifetime of the WSS. We only reset the fields that can change during its
 * lifetime.
 */
void wlp_wss_reset(struct wlp_wss *wss)
{
	memset(&wss->wssid, 0, sizeof(wss->wssid));
	wss->hash = 0;
	memset(&wss->name[0], 0, sizeof(wss->name));
	memset(&wss->bcast, 0, sizeof(wss->bcast));
	wss->secure_status = WLP_WSS_UNSECURE;
	memset(&wss->master_key[0], 0, sizeof(wss->master_key));
	wss->tag = 0;
	wss->state = WLP_WSS_STATE_NONE;
}

/**
 * Create sysfs infrastructure for WSS
 *
 * The WSS is configured to have the interface as parent (see wlp_wss_setup())
 * a new sysfs directory that includes wssid as its name is created in the
 * interface's sysfs directory. The group of files interacting with WSS are
 * created also.
 */
static
int wlp_wss_sysfs_add(struct wlp_wss *wss, char *wssid_str)
{
	struct wlp *wlp = container_of(wss, struct wlp, wss);
	struct device *dev = &wlp->rc->uwb_dev.dev;
	int result;

	result = kobject_set_name(&wss->kobj, "wss-%s", wssid_str);
	if (result < 0)
		return result;
	wss->kobj.ktype = &wss_ktype;
	result = kobject_init_and_add(&wss->kobj,
			&wss_ktype, wss->kobj.parent, "wlp");
	if (result < 0) {
		dev_err(dev, "WLP: Cannot register WSS kobject.\n");
		goto error_kobject_register;
	}
	result = sysfs_create_group(&wss->kobj, &wss_attr_group);
	if (result < 0) {
		dev_err(dev, "WLP: Cannot register WSS attributes: %d\n",
			result);
		goto error_sysfs_create_group;
	}
	return 0;
error_sysfs_create_group:

	kobject_put(&wss->kobj); /* will free name if needed */
	return result;
error_kobject_register:
	kfree(wss->kobj.name);
	wss->kobj.name = NULL;
	wss->kobj.ktype = NULL;
	return result;
}


/**
 * Release WSS
 *
 * No more references exist to this WSS. We should undo everything that was
 * done in wlp_wss_create_activate() except removing the group. The group
 * is not removed because an object can be unregistered before the group is
 * created. We also undo any additional operations on the WSS after this
 * (addition of members).
 *
 * If memory was allocated for the kobject's name then it will
 * be freed by the kobject system during this time.
 *
 * The EDA cache is removed and reinitilized when the WSS is removed. We
 * thus loose knowledge of members of this WSS at that time and need not do
 * it here.
 */
void wlp_wss_release(struct kobject *kobj)
{
	struct wlp_wss *wss = container_of(kobj, struct wlp_wss, kobj);

	wlp_wss_reset(wss);
}

/**
 * Enroll into a WSS using provided neighbor as registrar
 *
 * First search the neighborhood information to learn which neighbor is
 * referred to, next proceed with enrollment.
 *
 * &wss->mutex is held
 */
static
int wlp_wss_enroll_target(struct wlp_wss *wss, struct wlp_uuid *wssid,
			  struct uwb_dev_addr *dest)
{
	struct wlp *wlp = container_of(wss, struct wlp, wss);
	struct device *dev = &wlp->rc->uwb_dev.dev;
	struct wlp_neighbor_e *neighbor;
	int result = -ENXIO;
	struct uwb_dev_addr *dev_addr;

	mutex_lock(&wlp->nbmutex);
	list_for_each_entry(neighbor, &wlp->neighbors, node) {
		dev_addr = &neighbor->uwb_dev->dev_addr;
		if (!memcmp(dest, dev_addr, sizeof(*dest))) {
			result = wlp_enroll_neighbor(wlp, neighbor, wss, wssid);
			break;
		}
	}
	if (result == -ENXIO)
		dev_err(dev, "WLP: Cannot find neighbor %02x:%02x. \n",
			dest->data[1], dest->data[0]);
	mutex_unlock(&wlp->nbmutex);
	return result;
}

/**
 * Enroll into a WSS previously discovered
 *
 * User provides WSSID of WSS, search for neighbor that has this WSS
 * activated and attempt to enroll.
 *
 * &wss->mutex is held
 */
static
int wlp_wss_enroll_discovered(struct wlp_wss *wss, struct wlp_uuid *wssid)
{
	struct wlp *wlp = container_of(wss, struct wlp, wss);
	struct device *dev = &wlp->rc->uwb_dev.dev;
	struct wlp_neighbor_e *neighbor;
	struct wlp_wssid_e *wssid_e;
	char buf[WLP_WSS_UUID_STRSIZE];
	int result = -ENXIO;


	mutex_lock(&wlp->nbmutex);
	list_for_each_entry(neighbor, &wlp->neighbors, node) {
		list_for_each_entry(wssid_e, &neighbor->wssid, node) {
			if (!memcmp(wssid, &wssid_e->wssid, sizeof(*wssid))) {
				result = wlp_enroll_neighbor(wlp, neighbor,
							     wss, wssid);
				if (result == 0) /* enrollment success */
					goto out;
				break;
			}
		}
	}
out:
	if (result == -ENXIO) {
		wlp_wss_uuid_print(buf, sizeof(buf), wssid);
		dev_err(dev, "WLP: Cannot find WSSID %s in cache. \n", buf);
	}
	mutex_unlock(&wlp->nbmutex);
	return result;
}

/**
 * Enroll into WSS with provided WSSID, registrar may be provided
 *
 * @wss: out WSS that will be enrolled
 * @wssid: wssid of neighboring WSS that we want to enroll in
 * @devaddr: registrar can be specified, will be broadcast (ff:ff) if any
 *           neighbor can be used as registrar.
 *
 * &wss->mutex is held
 */
static
int wlp_wss_enroll(struct wlp_wss *wss, struct wlp_uuid *wssid,
		   struct uwb_dev_addr *devaddr)
{
	int result;
	struct wlp *wlp = container_of(wss, struct wlp, wss);
	struct device *dev = &wlp->rc->uwb_dev.dev;
	char buf[WLP_WSS_UUID_STRSIZE];
	struct uwb_dev_addr bcast = {.data = {0xff, 0xff} };

	wlp_wss_uuid_print(buf, sizeof(buf), wssid);

	if (wss->state != WLP_WSS_STATE_NONE) {
		dev_err(dev, "WLP: Already enrolled in WSS %s.\n", buf);
		result = -EEXIST;
		goto error;
	}
	if (!memcmp(&bcast, devaddr, sizeof(bcast)))
		result = wlp_wss_enroll_discovered(wss, wssid);
	else
		result = wlp_wss_enroll_target(wss, wssid, devaddr);
	if (result < 0) {
		dev_err(dev, "WLP: Unable to enroll into WSS %s, result %d \n",
			buf, result);
		goto error;
	}
	dev_dbg(dev, "Successfully enrolled into WSS %s \n", buf);
	result = wlp_wss_sysfs_add(wss, buf);
	if (result < 0) {
		dev_err(dev, "WLP: Unable to set up sysfs for WSS kobject.\n");
		wlp_wss_reset(wss);
	}
error:
	return result;

}

/**
 * Activate given WSS
 *
 * Prior to activation a WSS must be enrolled. To activate a WSS a device
 * includes the WSS hash in the WLP IE in its beacon in each superframe.
 * WLP 0.99 [7.2.5].
 *
 * The WSS tag is also computed at this time. We only support one activated
 * WSS so we can use the hash as a tag - there will never be a conflict.
 *
 * We currently only support one activated WSS so only one WSS hash is
 * included in the WLP IE.
 */
static
int wlp_wss_activate(struct wlp_wss *wss)
{
	struct wlp *wlp = container_of(wss, struct wlp, wss);
	struct device *dev = &wlp->rc->uwb_dev.dev;
	struct uwb_rc *uwb_rc = wlp->rc;
	int result;
	struct {
		struct wlp_ie wlp_ie;
		u8 hash; /* only include one hash */
	} ie_data;

	BUG_ON(wss->state != WLP_WSS_STATE_ENROLLED);
	wss->hash = wlp_wss_comp_wssid_hash(&wss->wssid);
	wss->tag = wss->hash;
	memset(&ie_data, 0, sizeof(ie_data));
	ie_data.wlp_ie.hdr.element_id = UWB_IE_WLP;
	ie_data.wlp_ie.hdr.length = sizeof(ie_data) - sizeof(struct uwb_ie_hdr);
	wlp_ie_set_hash_length(&ie_data.wlp_ie, sizeof(ie_data.hash));
	ie_data.hash = wss->hash;
	result = uwb_rc_ie_add(uwb_rc, &ie_data.wlp_ie.hdr,
			       sizeof(ie_data));
	if (result < 0) {
		dev_err(dev, "WLP: Unable to add WLP IE to beacon. "
			"result = %d.\n", result);
		goto error_wlp_ie;
	}
	wss->state = WLP_WSS_STATE_ACTIVE;
	result = 0;
error_wlp_ie:
	return result;
}

/**
 * Enroll in and activate WSS identified by provided WSSID
 *
 * The neighborhood cache should contain a list of all neighbors and the
 * WSS they have activated. Based on that cache we search which neighbor we
 * can perform the association process with. The user also has option to
 * specify which neighbor it prefers as registrar.
 * Successful enrollment is followed by activation.
 * Successful activation will create the sysfs directory containing
 * specific information regarding this WSS.
 */
int wlp_wss_enroll_activate(struct wlp_wss *wss, struct wlp_uuid *wssid,
			    struct uwb_dev_addr *devaddr)
{
	struct wlp *wlp = container_of(wss, struct wlp, wss);
	struct device *dev = &wlp->rc->uwb_dev.dev;
	int result = 0;
	char buf[WLP_WSS_UUID_STRSIZE];

	mutex_lock(&wss->mutex);
	result = wlp_wss_enroll(wss, wssid, devaddr);
	if (result < 0) {
		wlp_wss_uuid_print(buf, sizeof(buf), &wss->wssid);
		dev_err(dev, "WLP: Enrollment into WSS %s failed.\n", buf);
		goto error_enroll;
	}
	result = wlp_wss_activate(wss);
	if (result < 0) {
		dev_err(dev, "WLP: Unable to activate WSS. Undoing enrollment "
			"result = %d \n", result);
		/* Undo enrollment */
		wlp_wss_reset(wss);
		goto error_activate;
	}
error_activate:
error_enroll:
	mutex_unlock(&wss->mutex);
	return result;
}

/**
 * Create, enroll, and activate a new WSS
 *
 * @wssid: new wssid provided by user
 * @name:  WSS name requested by used.
 * @sec_status: security status requested by user
 *
 * A user requested the creation of a new WSS. All operations are done
 * locally. The new WSS will be stored locally, the hash will be included
 * in the WLP IE, and the sysfs infrastructure for this WSS will be
 * created.
 */
int wlp_wss_create_activate(struct wlp_wss *wss, struct wlp_uuid *wssid,
			    char *name, unsigned sec_status, unsigned accept)
{
	struct wlp *wlp = container_of(wss, struct wlp, wss);
	struct device *dev = &wlp->rc->uwb_dev.dev;
	int result = 0;
	char buf[WLP_WSS_UUID_STRSIZE];

	result = wlp_wss_uuid_print(buf, sizeof(buf), wssid);

	if (!mutex_trylock(&wss->mutex)) {
		dev_err(dev, "WLP: WLP association session in progress.\n");
		return -EBUSY;
	}
	if (wss->state != WLP_WSS_STATE_NONE) {
		dev_err(dev, "WLP: WSS already exists. Not creating new.\n");
		result = -EEXIST;
		goto out;
	}
	if (wss->kobj.parent == NULL) {
		dev_err(dev, "WLP: WSS parent not ready. Is network interface "
		       "up?\n");
		result = -ENXIO;
		goto out;
	}
	if (sec_status == WLP_WSS_SECURE) {
		dev_err(dev, "WLP: FIXME Creation of secure WSS not "
			"supported yet.\n");
		result = -EINVAL;
		goto out;
	}
	wss->wssid = *wssid;
	memcpy(wss->name, name, sizeof(wss->name));
	wss->bcast = wlp_wss_sel_bcast_addr(wss);
	wss->secure_status = sec_status;
	wss->accept_enroll = accept;
	/*wss->virtual_addr is initialized in call to wlp_wss_setup*/
	/* sysfs infrastructure */
	result = wlp_wss_sysfs_add(wss, buf);
	if (result < 0) {
		dev_err(dev, "Cannot set up sysfs for WSS kobject.\n");
		wlp_wss_reset(wss);
		goto out;
	} else
		result = 0;
	wss->state = WLP_WSS_STATE_ENROLLED;
	result = wlp_wss_activate(wss);
	if (result < 0) {
		dev_err(dev, "WLP: Unable to activate WSS. Undoing "
			"enrollment\n");
		wlp_wss_reset(wss);
		goto out;
	}
	result = 0;
out:
	mutex_unlock(&wss->mutex);
	return result;
}

/**
 * Determine if neighbor has WSS activated
 *
 * @returns: 1 if neighbor has WSS activated, zero otherwise
 *
 * This can be done in two ways:
 * - send a C1 frame, parse C2/F0 response
 * - examine the WLP IE sent by the neighbor
 *
 * The WLP IE is not fully supported in hardware so we use the C1/C2 frame
 * exchange to determine if a WSS is activated. Using the WLP IE should be
 * faster and should be used when it becomes possible.
 */
int wlp_wss_is_active(struct wlp *wlp, struct wlp_wss *wss,
		      struct uwb_dev_addr *dev_addr)
{
	int result = 0;
	struct device *dev = &wlp->rc->uwb_dev.dev;
	DECLARE_COMPLETION_ONSTACK(completion);
	struct wlp_session session;
	struct sk_buff  *skb;
	struct wlp_frame_assoc *resp;
	struct wlp_uuid wssid;

	mutex_lock(&wlp->mutex);
	/* Send C1 association frame */
	result = wlp_send_assoc_frame(wlp, wss, dev_addr, WLP_ASSOC_C1);
	if (result < 0) {
		dev_err(dev, "Unable to send C1 frame to neighbor "
			"%02x:%02x (%d)\n", dev_addr->data[1],
			dev_addr->data[0], result);
		result = 0;
		goto out;
	}
	/* Create session, wait for response */
	session.exp_message = WLP_ASSOC_C2;
	session.cb = wlp_session_cb;
	session.cb_priv = &completion;
	session.neighbor_addr = *dev_addr;
	BUG_ON(wlp->session != NULL);
	wlp->session = &session;
	/* Wait for C2/F0 frame */
	result = wait_for_completion_interruptible_timeout(&completion,
						   WLP_PER_MSG_TIMEOUT * HZ);
	if (result == 0) {
		dev_err(dev, "Timeout while sending C1 to neighbor "
			     "%02x:%02x.\n", dev_addr->data[1],
			     dev_addr->data[0]);
		goto out;
	}
	if (result < 0) {
		dev_err(dev, "Unable to send C1 to neighbor %02x:%02x.\n",
			dev_addr->data[1], dev_addr->data[0]);
		result = 0;
		goto out;
	}
	/* Parse message in session->data: it will be either C2 or F0 */
	skb = session.data;
	resp = (void *) skb->data;
	if (resp->type == WLP_ASSOC_F0) {
		result = wlp_parse_f0(wlp, skb);
		if (result < 0)
			dev_err(dev, "WLP:  unable to parse incoming F0 "
				"frame from neighbor %02x:%02x.\n",
				dev_addr->data[1], dev_addr->data[0]);
		result = 0;
		goto error_resp_parse;
	}
	/* WLP version and message type fields have already been parsed */
	result = wlp_get_wssid(wlp, (void *)resp + sizeof(*resp), &wssid,
			       skb->len - sizeof(*resp));
	if (result < 0) {
		dev_err(dev, "WLP: unable to obtain WSSID from C2 frame.\n");
		result = 0;
		goto error_resp_parse;
	}
	if (!memcmp(&wssid, &wss->wssid, sizeof(wssid)))
		result = 1;
	else {
		dev_err(dev, "WLP: Received a C2 frame without matching "
			"WSSID.\n");
		result = 0;
	}
error_resp_parse:
	kfree_skb(skb);
out:
	wlp->session = NULL;
	mutex_unlock(&wlp->mutex);
	return result;
}

/**
 * Activate connection with neighbor by updating EDA cache
 *
 * @wss:       local WSS to which neighbor wants to connect
 * @dev_addr:  neighbor's address
 * @wssid:     neighbor's WSSID - must be same as our WSS's WSSID
 * @tag:       neighbor's WSS tag used to identify frames transmitted by it
 * @virt_addr: neighbor's virtual EUI-48
 */
static
int wlp_wss_activate_connection(struct wlp *wlp, struct wlp_wss *wss,
				struct uwb_dev_addr *dev_addr,
				struct wlp_uuid *wssid, u8 *tag,
				struct uwb_mac_addr *virt_addr)
{
	struct device *dev = &wlp->rc->uwb_dev.dev;
	int result = 0;

	if (!memcmp(wssid, &wss->wssid, sizeof(*wssid))) {
		/* Update EDA cache */
		result = wlp_eda_update_node(&wlp->eda, dev_addr, wss,
					     (void *) virt_addr->data, *tag,
					     WLP_WSS_CONNECTED);
		if (result < 0)
			dev_err(dev, "WLP: Unable to update EDA cache "
				"with new connected neighbor information.\n");
	} else {
		dev_err(dev, "WLP: Neighbor does not have matching WSSID.\n");
		result = -EINVAL;
	}
	return result;
}

/**
 * Connect to WSS neighbor
 *
 * Use C3/C4 exchange to determine if neighbor has WSS activated and
 * retrieve the WSS tag and virtual EUI-48 of the neighbor.
 */
static
int wlp_wss_connect_neighbor(struct wlp *wlp, struct wlp_wss *wss,
			     struct uwb_dev_addr *dev_addr)
{
	int result;
	struct device *dev = &wlp->rc->uwb_dev.dev;
	struct wlp_uuid wssid;
	u8 tag;
	struct uwb_mac_addr virt_addr;
	DECLARE_COMPLETION_ONSTACK(completion);
	struct wlp_session session;
	struct wlp_frame_assoc *resp;
	struct sk_buff *skb;

	mutex_lock(&wlp->mutex);
	/* Send C3 association frame */
	result = wlp_send_assoc_frame(wlp, wss, dev_addr, WLP_ASSOC_C3);
	if (result < 0) {
		dev_err(dev, "Unable to send C3 frame to neighbor "
			"%02x:%02x (%d)\n", dev_addr->data[1],
			dev_addr->data[0], result);
		goto out;
	}
	/* Create session, wait for response */
	session.exp_message = WLP_ASSOC_C4;
	session.cb = wlp_session_cb;
	session.cb_priv = &completion;
	session.neighbor_addr = *dev_addr;
	BUG_ON(wlp->session != NULL);
	wlp->session = &session;
	/* Wait for C4/F0 frame */
	result = wait_for_completion_interruptible_timeout(&completion,
						   WLP_PER_MSG_TIMEOUT * HZ);
	if (result == 0) {
		dev_err(dev, "Timeout while sending C3 to neighbor "
			     "%02x:%02x.\n", dev_addr->data[1],
			     dev_addr->data[0]);
		result = -ETIMEDOUT;
		goto out;
	}
	if (result < 0) {
		dev_err(dev, "Unable to send C3 to neighbor %02x:%02x.\n",
			dev_addr->data[1], dev_addr->data[0]);
		goto out;
	}
	/* Parse message in session->data: it will be either C4 or F0 */
	skb = session.data;
	resp = (void *) skb->data;
	if (resp->type == WLP_ASSOC_F0) {
		result = wlp_parse_f0(wlp, skb);
		if (result < 0)
			dev_err(dev, "WLP: unable to parse incoming F0 "
				"frame from neighbor %02x:%02x.\n",
				dev_addr->data[1], dev_addr->data[0]);
		result = -EINVAL;
		goto error_resp_parse;
	}
	result = wlp_parse_c3c4_frame(wlp, skb, &wssid, &tag, &virt_addr);
	if (result < 0) {
		dev_err(dev, "WLP: Unable to parse C4 frame from neighbor.\n");
		goto error_resp_parse;
	}
	result = wlp_wss_activate_connection(wlp, wss, dev_addr, &wssid, &tag,
					     &virt_addr);
	if (result < 0) {
		dev_err(dev, "WLP: Unable to activate connection to "
			"neighbor %02x:%02x.\n", dev_addr->data[1],
			dev_addr->data[0]);
		goto error_resp_parse;
	}
error_resp_parse:
	kfree_skb(skb);
out:
	/* Record that we unsuccessfully tried to connect to this neighbor */
	if (result < 0)
		wlp_eda_update_node_state(&wlp->eda, dev_addr,
					  WLP_WSS_CONNECT_FAILED);
	wlp->session = NULL;
	mutex_unlock(&wlp->mutex);
	return result;
}

/**
 * Connect to neighbor with common WSS, send pending frame
 *
 * This function is scheduled when a frame is destined to a neighbor with
 * which we do not have a connection. A copy of the EDA cache entry is
 * provided - not the actual cache entry (because it is protected by a
 * spinlock).
 *
 * First determine if neighbor has the same WSS activated, connect if it
 * does. The C3/C4 exchange is dual purpose to determine if neighbor has
 * WSS activated and proceed with the connection.
 *
 * The frame that triggered the connection setup is sent after connection
 * setup.
 *
 * network queue is stopped - we need to restart when done
 *
 */
static
void wlp_wss_connect_send(struct work_struct *ws)
{
	struct wlp_assoc_conn_ctx *conn_ctx = container_of(ws,
						  struct wlp_assoc_conn_ctx,
						  ws);
	struct wlp *wlp = conn_ctx->wlp;
	struct sk_buff *skb = conn_ctx->skb;
	struct wlp_eda_node *eda_entry = &conn_ctx->eda_entry;
	struct uwb_dev_addr *dev_addr = &eda_entry->dev_addr;
	struct wlp_wss *wss = &wlp->wss;
	int result;
	struct device *dev = &wlp->rc->uwb_dev.dev;

	mutex_lock(&wss->mutex);
	if (wss->state < WLP_WSS_STATE_ACTIVE) {
		if (printk_ratelimit())
			dev_err(dev, "WLP: Attempting to connect with "
				"WSS that is not active or connected.\n");
		dev_kfree_skb(skb);
		goto out;
	}
	/* Establish connection - send C3 rcv C4 */
	result = wlp_wss_connect_neighbor(wlp, wss, dev_addr);
	if (result < 0) {
		if (printk_ratelimit())
			dev_err(dev, "WLP: Unable to establish connection "
				"with neighbor %02x:%02x.\n",
				dev_addr->data[1], dev_addr->data[0]);
		dev_kfree_skb(skb);
		goto out;
	}
	/* EDA entry changed, update the local copy being used */
	result = wlp_copy_eda_node(&wlp->eda, dev_addr, eda_entry);
	if (result < 0) {
		if (printk_ratelimit())
			dev_err(dev, "WLP: Cannot find EDA entry for "
				"neighbor %02x:%02x \n",
				dev_addr->data[1], dev_addr->data[0]);
	}
	result = wlp_wss_prep_hdr(wlp, eda_entry, skb);
	if (result < 0) {
		if (printk_ratelimit())
			dev_err(dev, "WLP: Unable to prepare frame header for "
				"transmission (neighbor %02x:%02x). \n",
				dev_addr->data[1], dev_addr->data[0]);
		dev_kfree_skb(skb);
		goto out;
	}
	BUG_ON(wlp->xmit_frame == NULL);
	result = wlp->xmit_frame(wlp, skb, dev_addr);
	if (result < 0) {
		if (printk_ratelimit())
			dev_err(dev, "WLP: Unable to transmit frame: %d\n",
				result);
		if (result == -ENXIO)
			dev_err(dev, "WLP: Is network interface up? \n");
		/* We could try again ... */
		dev_kfree_skb(skb);/*we need to free if tx fails */
	}
out:
	kfree(conn_ctx);
	BUG_ON(wlp->start_queue == NULL);
	wlp->start_queue(wlp);
	mutex_unlock(&wss->mutex);
}

/**
 * Add WLP header to outgoing skb
 *
 * @eda_entry: pointer to neighbor's entry in the EDA cache
 * @_skb:      skb containing data destined to the neighbor
 */
int wlp_wss_prep_hdr(struct wlp *wlp, struct wlp_eda_node *eda_entry,
		     void *_skb)
{
	struct device *dev = &wlp->rc->uwb_dev.dev;
	int result = 0;
	unsigned char *eth_addr = eda_entry->eth_addr;
	struct uwb_dev_addr *dev_addr = &eda_entry->dev_addr;
	struct sk_buff *skb = _skb;
	struct wlp_frame_std_abbrv_hdr *std_hdr;

	if (eda_entry->state == WLP_WSS_CONNECTED) {
		/* Add WLP header */
		BUG_ON(skb_headroom(skb) < sizeof(*std_hdr));
		std_hdr = (void *) __skb_push(skb, sizeof(*std_hdr));
		std_hdr->hdr.mux_hdr = cpu_to_le16(WLP_PROTOCOL_ID);
		std_hdr->hdr.type = WLP_FRAME_STANDARD;
		std_hdr->tag = eda_entry->wss->tag;
	} else {
		if (printk_ratelimit())
			dev_err(dev, "WLP: Destination neighbor (Ethernet: "
				"%02x:%02x:%02x:%02x:%02x:%02x, Dev: "
				"%02x:%02x) is not connected. \n", eth_addr[0],
				eth_addr[1], eth_addr[2], eth_addr[3],
				eth_addr[4], eth_addr[5], dev_addr->data[1],
				dev_addr->data[0]);
		result = -EINVAL;
	}
	return result;
}


/**
 * Prepare skb for neighbor: connect if not already and prep WLP header
 *
 * This function is called in interrupt context, but it needs to sleep. We
 * temporarily stop the net queue to establish the WLP connection.
 * Setup of the WLP connection and restart of queue is scheduled
 * on the default work queue.
 *
 * run with eda->lock held (spinlock)
 */
int wlp_wss_connect_prep(struct wlp *wlp, struct wlp_eda_node *eda_entry,
			 void *_skb)
{
	int result = 0;
	struct device *dev = &wlp->rc->uwb_dev.dev;
	struct sk_buff *skb = _skb;
	struct wlp_assoc_conn_ctx *conn_ctx;

	if (eda_entry->state == WLP_WSS_UNCONNECTED) {
		/* We don't want any more packets while we set up connection */
		BUG_ON(wlp->stop_queue == NULL);
		wlp->stop_queue(wlp);
		conn_ctx = kmalloc(sizeof(*conn_ctx), GFP_ATOMIC);
		if (conn_ctx == NULL) {
			if (printk_ratelimit())
				dev_err(dev, "WLP: Unable to allocate memory "
					"for connection handling.\n");
			result = -ENOMEM;
			goto out;
		}
		conn_ctx->wlp = wlp;
		conn_ctx->skb = skb;
		conn_ctx->eda_entry = *eda_entry;
		INIT_WORK(&conn_ctx->ws, wlp_wss_connect_send);
		schedule_work(&conn_ctx->ws);
		result = 1;
	} else if (eda_entry->state == WLP_WSS_CONNECT_FAILED) {
		/* Previous connection attempts failed, don't retry - see
		 * conditions for connection in WLP 0.99 [7.6.2] */
		if (printk_ratelimit())
			dev_err(dev, "Could not connect to neighbor "
			 "previously. Not retrying. \n");
		result = -ENONET;
		goto out;
	} else /* eda_entry->state == WLP_WSS_CONNECTED */
		result = wlp_wss_prep_hdr(wlp, eda_entry, skb);
out:
	return result;
}

/**
 * Emulate broadcast: copy skb, send copy to neighbor (connect if not already)
 *
 * We need to copy skbs in the case where we emulate broadcast through
 * unicast. We copy instead of clone because we are modifying the data of
 * the frame after copying ... clones share data so we cannot emulate
 * broadcast using clones.
 *
 * run with eda->lock held (spinlock)
 */
int wlp_wss_send_copy(struct wlp *wlp, struct wlp_eda_node *eda_entry,
		      void *_skb)
{
	int result = -ENOMEM;
	struct device *dev = &wlp->rc->uwb_dev.dev;
	struct sk_buff *skb = _skb;
	struct sk_buff *copy;
	struct uwb_dev_addr *dev_addr = &eda_entry->dev_addr;

	copy = skb_copy(skb, GFP_ATOMIC);
	if (copy == NULL) {
		if (printk_ratelimit())
			dev_err(dev, "WLP: Unable to copy skb for "
				"transmission.\n");
		goto out;
	}
	result = wlp_wss_connect_prep(wlp, eda_entry, copy);
	if (result < 0) {
		if (printk_ratelimit())
			dev_err(dev, "WLP: Unable to connect/send skb "
				"to neighbor.\n");
		dev_kfree_skb_irq(copy);
		goto out;
	} else if (result == 1)
		/* Frame will be transmitted separately */
		goto out;
	BUG_ON(wlp->xmit_frame == NULL);
	result = wlp->xmit_frame(wlp, copy, dev_addr);
	if (result < 0) {
		if (printk_ratelimit())
			dev_err(dev, "WLP: Unable to transmit frame: %d\n",
				result);
		if ((result == -ENXIO) && printk_ratelimit())
			dev_err(dev, "WLP: Is network interface up? \n");
		/* We could try again ... */
		dev_kfree_skb_irq(copy);/*we need to free if tx fails */
	}
out:
	return result;
}


/**
 * Setup WSS
 *
 * Should be called by network driver after the interface has been given a
 * MAC address.
 */
int wlp_wss_setup(struct net_device *net_dev, struct wlp_wss *wss)
{
	struct wlp *wlp = container_of(wss, struct wlp, wss);
	struct device *dev = &wlp->rc->uwb_dev.dev;
	int result = 0;

	mutex_lock(&wss->mutex);
	wss->kobj.parent = &net_dev->dev.kobj;
	if (!is_valid_ether_addr(net_dev->dev_addr)) {
		dev_err(dev, "WLP: Invalid MAC address. Cannot use for"
		       "virtual.\n");
		result = -EINVAL;
		goto out;
	}
	memcpy(wss->virtual_addr.data, net_dev->dev_addr,
	       sizeof(wss->virtual_addr.data));
out:
	mutex_unlock(&wss->mutex);
	return result;
}
EXPORT_SYMBOL_GPL(wlp_wss_setup);

/**
 * Remove WSS
 *
 * Called by client that configured WSS through wlp_wss_setup(). This
 * function is called when client no longer needs WSS, eg. client shuts
 * down.
 *
 * We remove the WLP IE from the beacon before initiating local cleanup.
 */
void wlp_wss_remove(struct wlp_wss *wss)
{
	struct wlp *wlp = container_of(wss, struct wlp, wss);

	mutex_lock(&wss->mutex);
	if (wss->state == WLP_WSS_STATE_ACTIVE)
		uwb_rc_ie_rm(wlp->rc, UWB_IE_WLP);
	if (wss->state != WLP_WSS_STATE_NONE) {
		sysfs_remove_group(&wss->kobj, &wss_attr_group);
		kobject_put(&wss->kobj);
	}
	wss->kobj.parent = NULL;
	memset(&wss->virtual_addr, 0, sizeof(wss->virtual_addr));
	/* Cleanup EDA cache */
	wlp_eda_release(&wlp->eda);
	wlp_eda_init(&wlp->eda);
	mutex_unlock(&wss->mutex);
}
EXPORT_SYMBOL_GPL(wlp_wss_remove);