xref: /linux/net/nfc/llcp_core.c (revision 2d87650a3bf1b80f7d0d150ee1af3f8a89e5b7aa)
1 /*
2  * Copyright (C) 2011  Intel Corporation. All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #define pr_fmt(fmt) "llcp: %s: " fmt, __func__
19 
20 #include <linux/init.h>
21 #include <linux/kernel.h>
22 #include <linux/list.h>
23 #include <linux/nfc.h>
24 
25 #include "nfc.h"
26 #include "llcp.h"
27 
28 static u8 llcp_magic[3] = {0x46, 0x66, 0x6d};
29 
30 static struct list_head llcp_devices;
31 
32 static void nfc_llcp_rx_skb(struct nfc_llcp_local *local, struct sk_buff *skb);
33 
34 void nfc_llcp_sock_link(struct llcp_sock_list *l, struct sock *sk)
35 {
36 	write_lock(&l->lock);
37 	sk_add_node(sk, &l->head);
38 	write_unlock(&l->lock);
39 }
40 
41 void nfc_llcp_sock_unlink(struct llcp_sock_list *l, struct sock *sk)
42 {
43 	write_lock(&l->lock);
44 	sk_del_node_init(sk);
45 	write_unlock(&l->lock);
46 }
47 
48 void nfc_llcp_socket_remote_param_init(struct nfc_llcp_sock *sock)
49 {
50 	sock->remote_rw = LLCP_DEFAULT_RW;
51 	sock->remote_miu = LLCP_MAX_MIU + 1;
52 }
53 
54 static void nfc_llcp_socket_purge(struct nfc_llcp_sock *sock)
55 {
56 	struct nfc_llcp_local *local = sock->local;
57 	struct sk_buff *s, *tmp;
58 
59 	pr_debug("%p\n", &sock->sk);
60 
61 	skb_queue_purge(&sock->tx_queue);
62 	skb_queue_purge(&sock->tx_pending_queue);
63 
64 	if (local == NULL)
65 		return;
66 
67 	/* Search for local pending SKBs that are related to this socket */
68 	skb_queue_walk_safe(&local->tx_queue, s, tmp) {
69 		if (s->sk != &sock->sk)
70 			continue;
71 
72 		skb_unlink(s, &local->tx_queue);
73 		kfree_skb(s);
74 	}
75 }
76 
77 static void nfc_llcp_socket_release(struct nfc_llcp_local *local, bool device,
78 				    int err)
79 {
80 	struct sock *sk;
81 	struct hlist_node *tmp;
82 	struct nfc_llcp_sock *llcp_sock;
83 
84 	skb_queue_purge(&local->tx_queue);
85 
86 	write_lock(&local->sockets.lock);
87 
88 	sk_for_each_safe(sk, tmp, &local->sockets.head) {
89 		llcp_sock = nfc_llcp_sock(sk);
90 
91 		bh_lock_sock(sk);
92 
93 		nfc_llcp_socket_purge(llcp_sock);
94 
95 		if (sk->sk_state == LLCP_CONNECTED)
96 			nfc_put_device(llcp_sock->dev);
97 
98 		if (sk->sk_state == LLCP_LISTEN) {
99 			struct nfc_llcp_sock *lsk, *n;
100 			struct sock *accept_sk;
101 
102 			list_for_each_entry_safe(lsk, n,
103 						 &llcp_sock->accept_queue,
104 						 accept_queue) {
105 				accept_sk = &lsk->sk;
106 				bh_lock_sock(accept_sk);
107 
108 				nfc_llcp_accept_unlink(accept_sk);
109 
110 				if (err)
111 					accept_sk->sk_err = err;
112 				accept_sk->sk_state = LLCP_CLOSED;
113 				accept_sk->sk_state_change(sk);
114 
115 				bh_unlock_sock(accept_sk);
116 			}
117 		}
118 
119 		if (err)
120 			sk->sk_err = err;
121 		sk->sk_state = LLCP_CLOSED;
122 		sk->sk_state_change(sk);
123 
124 		bh_unlock_sock(sk);
125 
126 		sk_del_node_init(sk);
127 	}
128 
129 	write_unlock(&local->sockets.lock);
130 
131 	/* If we still have a device, we keep the RAW sockets alive */
132 	if (device == true)
133 		return;
134 
135 	write_lock(&local->raw_sockets.lock);
136 
137 	sk_for_each_safe(sk, tmp, &local->raw_sockets.head) {
138 		llcp_sock = nfc_llcp_sock(sk);
139 
140 		bh_lock_sock(sk);
141 
142 		nfc_llcp_socket_purge(llcp_sock);
143 
144 		if (err)
145 			sk->sk_err = err;
146 		sk->sk_state = LLCP_CLOSED;
147 		sk->sk_state_change(sk);
148 
149 		bh_unlock_sock(sk);
150 
151 		sk_del_node_init(sk);
152 	}
153 
154 	write_unlock(&local->raw_sockets.lock);
155 }
156 
157 struct nfc_llcp_local *nfc_llcp_local_get(struct nfc_llcp_local *local)
158 {
159 	kref_get(&local->ref);
160 
161 	return local;
162 }
163 
164 static void local_cleanup(struct nfc_llcp_local *local)
165 {
166 	nfc_llcp_socket_release(local, false, ENXIO);
167 	del_timer_sync(&local->link_timer);
168 	skb_queue_purge(&local->tx_queue);
169 	cancel_work_sync(&local->tx_work);
170 	cancel_work_sync(&local->rx_work);
171 	cancel_work_sync(&local->timeout_work);
172 	kfree_skb(local->rx_pending);
173 	del_timer_sync(&local->sdreq_timer);
174 	cancel_work_sync(&local->sdreq_timeout_work);
175 	nfc_llcp_free_sdp_tlv_list(&local->pending_sdreqs);
176 }
177 
178 static void local_release(struct kref *ref)
179 {
180 	struct nfc_llcp_local *local;
181 
182 	local = container_of(ref, struct nfc_llcp_local, ref);
183 
184 	list_del(&local->list);
185 	local_cleanup(local);
186 	kfree(local);
187 }
188 
189 int nfc_llcp_local_put(struct nfc_llcp_local *local)
190 {
191 	if (local == NULL)
192 		return 0;
193 
194 	return kref_put(&local->ref, local_release);
195 }
196 
197 static struct nfc_llcp_sock *nfc_llcp_sock_get(struct nfc_llcp_local *local,
198 					       u8 ssap, u8 dsap)
199 {
200 	struct sock *sk;
201 	struct nfc_llcp_sock *llcp_sock, *tmp_sock;
202 
203 	pr_debug("ssap dsap %d %d\n", ssap, dsap);
204 
205 	if (ssap == 0 && dsap == 0)
206 		return NULL;
207 
208 	read_lock(&local->sockets.lock);
209 
210 	llcp_sock = NULL;
211 
212 	sk_for_each(sk, &local->sockets.head) {
213 		tmp_sock = nfc_llcp_sock(sk);
214 
215 		if (tmp_sock->ssap == ssap && tmp_sock->dsap == dsap) {
216 			llcp_sock = tmp_sock;
217 			break;
218 		}
219 	}
220 
221 	read_unlock(&local->sockets.lock);
222 
223 	if (llcp_sock == NULL)
224 		return NULL;
225 
226 	sock_hold(&llcp_sock->sk);
227 
228 	return llcp_sock;
229 }
230 
231 static void nfc_llcp_sock_put(struct nfc_llcp_sock *sock)
232 {
233 	sock_put(&sock->sk);
234 }
235 
236 static void nfc_llcp_timeout_work(struct work_struct *work)
237 {
238 	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
239 						    timeout_work);
240 
241 	nfc_dep_link_down(local->dev);
242 }
243 
244 static void nfc_llcp_symm_timer(unsigned long data)
245 {
246 	struct nfc_llcp_local *local = (struct nfc_llcp_local *) data;
247 
248 	pr_err("SYMM timeout\n");
249 
250 	schedule_work(&local->timeout_work);
251 }
252 
253 static void nfc_llcp_sdreq_timeout_work(struct work_struct *work)
254 {
255 	unsigned long time;
256 	HLIST_HEAD(nl_sdres_list);
257 	struct hlist_node *n;
258 	struct nfc_llcp_sdp_tlv *sdp;
259 	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
260 						    sdreq_timeout_work);
261 
262 	mutex_lock(&local->sdreq_lock);
263 
264 	time = jiffies - msecs_to_jiffies(3 * local->remote_lto);
265 
266 	hlist_for_each_entry_safe(sdp, n, &local->pending_sdreqs, node) {
267 		if (time_after(sdp->time, time))
268 			continue;
269 
270 		sdp->sap = LLCP_SDP_UNBOUND;
271 
272 		hlist_del(&sdp->node);
273 
274 		hlist_add_head(&sdp->node, &nl_sdres_list);
275 	}
276 
277 	if (!hlist_empty(&local->pending_sdreqs))
278 		mod_timer(&local->sdreq_timer,
279 			  jiffies + msecs_to_jiffies(3 * local->remote_lto));
280 
281 	mutex_unlock(&local->sdreq_lock);
282 
283 	if (!hlist_empty(&nl_sdres_list))
284 		nfc_genl_llc_send_sdres(local->dev, &nl_sdres_list);
285 }
286 
287 static void nfc_llcp_sdreq_timer(unsigned long data)
288 {
289 	struct nfc_llcp_local *local = (struct nfc_llcp_local *) data;
290 
291 	schedule_work(&local->sdreq_timeout_work);
292 }
293 
294 struct nfc_llcp_local *nfc_llcp_find_local(struct nfc_dev *dev)
295 {
296 	struct nfc_llcp_local *local, *n;
297 
298 	list_for_each_entry_safe(local, n, &llcp_devices, list)
299 		if (local->dev == dev)
300 			return local;
301 
302 	pr_debug("No device found\n");
303 
304 	return NULL;
305 }
306 
307 static char *wks[] = {
308 	NULL,
309 	NULL, /* SDP */
310 	"urn:nfc:sn:ip",
311 	"urn:nfc:sn:obex",
312 	"urn:nfc:sn:snep",
313 };
314 
315 static int nfc_llcp_wks_sap(char *service_name, size_t service_name_len)
316 {
317 	int sap, num_wks;
318 
319 	pr_debug("%s\n", service_name);
320 
321 	if (service_name == NULL)
322 		return -EINVAL;
323 
324 	num_wks = ARRAY_SIZE(wks);
325 
326 	for (sap = 0; sap < num_wks; sap++) {
327 		if (wks[sap] == NULL)
328 			continue;
329 
330 		if (strncmp(wks[sap], service_name, service_name_len) == 0)
331 			return sap;
332 	}
333 
334 	return -EINVAL;
335 }
336 
337 static
338 struct nfc_llcp_sock *nfc_llcp_sock_from_sn(struct nfc_llcp_local *local,
339 					    u8 *sn, size_t sn_len)
340 {
341 	struct sock *sk;
342 	struct nfc_llcp_sock *llcp_sock, *tmp_sock;
343 
344 	pr_debug("sn %zd %p\n", sn_len, sn);
345 
346 	if (sn == NULL || sn_len == 0)
347 		return NULL;
348 
349 	read_lock(&local->sockets.lock);
350 
351 	llcp_sock = NULL;
352 
353 	sk_for_each(sk, &local->sockets.head) {
354 		tmp_sock = nfc_llcp_sock(sk);
355 
356 		pr_debug("llcp sock %p\n", tmp_sock);
357 
358 		if (tmp_sock->sk.sk_type == SOCK_STREAM &&
359 		    tmp_sock->sk.sk_state != LLCP_LISTEN)
360 			continue;
361 
362 		if (tmp_sock->sk.sk_type == SOCK_DGRAM &&
363 		    tmp_sock->sk.sk_state != LLCP_BOUND)
364 			continue;
365 
366 		if (tmp_sock->service_name == NULL ||
367 		    tmp_sock->service_name_len == 0)
368 			continue;
369 
370 		if (tmp_sock->service_name_len != sn_len)
371 			continue;
372 
373 		if (memcmp(sn, tmp_sock->service_name, sn_len) == 0) {
374 			llcp_sock = tmp_sock;
375 			break;
376 		}
377 	}
378 
379 	read_unlock(&local->sockets.lock);
380 
381 	pr_debug("Found llcp sock %p\n", llcp_sock);
382 
383 	return llcp_sock;
384 }
385 
386 u8 nfc_llcp_get_sdp_ssap(struct nfc_llcp_local *local,
387 			 struct nfc_llcp_sock *sock)
388 {
389 	mutex_lock(&local->sdp_lock);
390 
391 	if (sock->service_name != NULL && sock->service_name_len > 0) {
392 		int ssap = nfc_llcp_wks_sap(sock->service_name,
393 					    sock->service_name_len);
394 
395 		if (ssap > 0) {
396 			pr_debug("WKS %d\n", ssap);
397 
398 			/* This is a WKS, let's check if it's free */
399 			if (local->local_wks & BIT(ssap)) {
400 				mutex_unlock(&local->sdp_lock);
401 
402 				return LLCP_SAP_MAX;
403 			}
404 
405 			set_bit(ssap, &local->local_wks);
406 			mutex_unlock(&local->sdp_lock);
407 
408 			return ssap;
409 		}
410 
411 		/*
412 		 * Check if there already is a non WKS socket bound
413 		 * to this service name.
414 		 */
415 		if (nfc_llcp_sock_from_sn(local, sock->service_name,
416 					  sock->service_name_len) != NULL) {
417 			mutex_unlock(&local->sdp_lock);
418 
419 			return LLCP_SAP_MAX;
420 		}
421 
422 		mutex_unlock(&local->sdp_lock);
423 
424 		return LLCP_SDP_UNBOUND;
425 
426 	} else if (sock->ssap != 0 && sock->ssap < LLCP_WKS_NUM_SAP) {
427 		if (!test_bit(sock->ssap, &local->local_wks)) {
428 			set_bit(sock->ssap, &local->local_wks);
429 			mutex_unlock(&local->sdp_lock);
430 
431 			return sock->ssap;
432 		}
433 	}
434 
435 	mutex_unlock(&local->sdp_lock);
436 
437 	return LLCP_SAP_MAX;
438 }
439 
440 u8 nfc_llcp_get_local_ssap(struct nfc_llcp_local *local)
441 {
442 	u8 local_ssap;
443 
444 	mutex_lock(&local->sdp_lock);
445 
446 	local_ssap = find_first_zero_bit(&local->local_sap, LLCP_LOCAL_NUM_SAP);
447 	if (local_ssap == LLCP_LOCAL_NUM_SAP) {
448 		mutex_unlock(&local->sdp_lock);
449 		return LLCP_SAP_MAX;
450 	}
451 
452 	set_bit(local_ssap, &local->local_sap);
453 
454 	mutex_unlock(&local->sdp_lock);
455 
456 	return local_ssap + LLCP_LOCAL_SAP_OFFSET;
457 }
458 
459 void nfc_llcp_put_ssap(struct nfc_llcp_local *local, u8 ssap)
460 {
461 	u8 local_ssap;
462 	unsigned long *sdp;
463 
464 	if (ssap < LLCP_WKS_NUM_SAP) {
465 		local_ssap = ssap;
466 		sdp = &local->local_wks;
467 	} else if (ssap < LLCP_LOCAL_NUM_SAP) {
468 		atomic_t *client_cnt;
469 
470 		local_ssap = ssap - LLCP_WKS_NUM_SAP;
471 		sdp = &local->local_sdp;
472 		client_cnt = &local->local_sdp_cnt[local_ssap];
473 
474 		pr_debug("%d clients\n", atomic_read(client_cnt));
475 
476 		mutex_lock(&local->sdp_lock);
477 
478 		if (atomic_dec_and_test(client_cnt)) {
479 			struct nfc_llcp_sock *l_sock;
480 
481 			pr_debug("No more clients for SAP %d\n", ssap);
482 
483 			clear_bit(local_ssap, sdp);
484 
485 			/* Find the listening sock and set it back to UNBOUND */
486 			l_sock = nfc_llcp_sock_get(local, ssap, LLCP_SAP_SDP);
487 			if (l_sock) {
488 				l_sock->ssap = LLCP_SDP_UNBOUND;
489 				nfc_llcp_sock_put(l_sock);
490 			}
491 		}
492 
493 		mutex_unlock(&local->sdp_lock);
494 
495 		return;
496 	} else if (ssap < LLCP_MAX_SAP) {
497 		local_ssap = ssap - LLCP_LOCAL_NUM_SAP;
498 		sdp = &local->local_sap;
499 	} else {
500 		return;
501 	}
502 
503 	mutex_lock(&local->sdp_lock);
504 
505 	clear_bit(local_ssap, sdp);
506 
507 	mutex_unlock(&local->sdp_lock);
508 }
509 
510 static u8 nfc_llcp_reserve_sdp_ssap(struct nfc_llcp_local *local)
511 {
512 	u8 ssap;
513 
514 	mutex_lock(&local->sdp_lock);
515 
516 	ssap = find_first_zero_bit(&local->local_sdp, LLCP_SDP_NUM_SAP);
517 	if (ssap == LLCP_SDP_NUM_SAP) {
518 		mutex_unlock(&local->sdp_lock);
519 
520 		return LLCP_SAP_MAX;
521 	}
522 
523 	pr_debug("SDP ssap %d\n", LLCP_WKS_NUM_SAP + ssap);
524 
525 	set_bit(ssap, &local->local_sdp);
526 
527 	mutex_unlock(&local->sdp_lock);
528 
529 	return LLCP_WKS_NUM_SAP + ssap;
530 }
531 
532 static int nfc_llcp_build_gb(struct nfc_llcp_local *local)
533 {
534 	u8 *gb_cur, *version_tlv, version, version_length;
535 	u8 *lto_tlv, lto_length;
536 	u8 *wks_tlv, wks_length;
537 	u8 *miux_tlv, miux_length;
538 	__be16 wks = cpu_to_be16(local->local_wks);
539 	u8 gb_len = 0;
540 	int ret = 0;
541 
542 	version = LLCP_VERSION_11;
543 	version_tlv = nfc_llcp_build_tlv(LLCP_TLV_VERSION, &version,
544 					 1, &version_length);
545 	gb_len += version_length;
546 
547 	lto_tlv = nfc_llcp_build_tlv(LLCP_TLV_LTO, &local->lto, 1, &lto_length);
548 	gb_len += lto_length;
549 
550 	pr_debug("Local wks 0x%lx\n", local->local_wks);
551 	wks_tlv = nfc_llcp_build_tlv(LLCP_TLV_WKS, (u8 *)&wks, 2, &wks_length);
552 	gb_len += wks_length;
553 
554 	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&local->miux, 0,
555 				      &miux_length);
556 	gb_len += miux_length;
557 
558 	gb_len += ARRAY_SIZE(llcp_magic);
559 
560 	if (gb_len > NFC_MAX_GT_LEN) {
561 		ret = -EINVAL;
562 		goto out;
563 	}
564 
565 	gb_cur = local->gb;
566 
567 	memcpy(gb_cur, llcp_magic, ARRAY_SIZE(llcp_magic));
568 	gb_cur += ARRAY_SIZE(llcp_magic);
569 
570 	memcpy(gb_cur, version_tlv, version_length);
571 	gb_cur += version_length;
572 
573 	memcpy(gb_cur, lto_tlv, lto_length);
574 	gb_cur += lto_length;
575 
576 	memcpy(gb_cur, wks_tlv, wks_length);
577 	gb_cur += wks_length;
578 
579 	memcpy(gb_cur, miux_tlv, miux_length);
580 	gb_cur += miux_length;
581 
582 	local->gb_len = gb_len;
583 
584 out:
585 	kfree(version_tlv);
586 	kfree(lto_tlv);
587 	kfree(wks_tlv);
588 	kfree(miux_tlv);
589 
590 	return ret;
591 }
592 
593 u8 *nfc_llcp_general_bytes(struct nfc_dev *dev, size_t *general_bytes_len)
594 {
595 	struct nfc_llcp_local *local;
596 
597 	local = nfc_llcp_find_local(dev);
598 	if (local == NULL) {
599 		*general_bytes_len = 0;
600 		return NULL;
601 	}
602 
603 	nfc_llcp_build_gb(local);
604 
605 	*general_bytes_len = local->gb_len;
606 
607 	return local->gb;
608 }
609 
610 int nfc_llcp_set_remote_gb(struct nfc_dev *dev, u8 *gb, u8 gb_len)
611 {
612 	struct nfc_llcp_local *local = nfc_llcp_find_local(dev);
613 
614 	if (local == NULL) {
615 		pr_err("No LLCP device\n");
616 		return -ENODEV;
617 	}
618 	if (gb_len < 3)
619 		return -EINVAL;
620 
621 	memset(local->remote_gb, 0, NFC_MAX_GT_LEN);
622 	memcpy(local->remote_gb, gb, gb_len);
623 	local->remote_gb_len = gb_len;
624 
625 	if (memcmp(local->remote_gb, llcp_magic, 3)) {
626 		pr_err("MAC does not support LLCP\n");
627 		return -EINVAL;
628 	}
629 
630 	return nfc_llcp_parse_gb_tlv(local,
631 				     &local->remote_gb[3],
632 				     local->remote_gb_len - 3);
633 }
634 
635 static u8 nfc_llcp_dsap(struct sk_buff *pdu)
636 {
637 	return (pdu->data[0] & 0xfc) >> 2;
638 }
639 
640 static u8 nfc_llcp_ptype(struct sk_buff *pdu)
641 {
642 	return ((pdu->data[0] & 0x03) << 2) | ((pdu->data[1] & 0xc0) >> 6);
643 }
644 
645 static u8 nfc_llcp_ssap(struct sk_buff *pdu)
646 {
647 	return pdu->data[1] & 0x3f;
648 }
649 
650 static u8 nfc_llcp_ns(struct sk_buff *pdu)
651 {
652 	return pdu->data[2] >> 4;
653 }
654 
655 static u8 nfc_llcp_nr(struct sk_buff *pdu)
656 {
657 	return pdu->data[2] & 0xf;
658 }
659 
660 static void nfc_llcp_set_nrns(struct nfc_llcp_sock *sock, struct sk_buff *pdu)
661 {
662 	pdu->data[2] = (sock->send_n << 4) | (sock->recv_n);
663 	sock->send_n = (sock->send_n + 1) % 16;
664 	sock->recv_ack_n = (sock->recv_n - 1) % 16;
665 }
666 
667 void nfc_llcp_send_to_raw_sock(struct nfc_llcp_local *local,
668 			       struct sk_buff *skb, u8 direction)
669 {
670 	struct sk_buff *skb_copy = NULL, *nskb;
671 	struct sock *sk;
672 	u8 *data;
673 
674 	read_lock(&local->raw_sockets.lock);
675 
676 	sk_for_each(sk, &local->raw_sockets.head) {
677 		if (sk->sk_state != LLCP_BOUND)
678 			continue;
679 
680 		if (skb_copy == NULL) {
681 			skb_copy = __pskb_copy(skb, NFC_LLCP_RAW_HEADER_SIZE,
682 					       GFP_ATOMIC);
683 
684 			if (skb_copy == NULL)
685 				continue;
686 
687 			data = skb_push(skb_copy, NFC_LLCP_RAW_HEADER_SIZE);
688 
689 			data[0] = local->dev ? local->dev->idx : 0xFF;
690 			data[1] = direction;
691 		}
692 
693 		nskb = skb_clone(skb_copy, GFP_ATOMIC);
694 		if (!nskb)
695 			continue;
696 
697 		if (sock_queue_rcv_skb(sk, nskb))
698 			kfree_skb(nskb);
699 	}
700 
701 	read_unlock(&local->raw_sockets.lock);
702 
703 	kfree_skb(skb_copy);
704 }
705 
706 static void nfc_llcp_tx_work(struct work_struct *work)
707 {
708 	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
709 						    tx_work);
710 	struct sk_buff *skb;
711 	struct sock *sk;
712 	struct nfc_llcp_sock *llcp_sock;
713 
714 	skb = skb_dequeue(&local->tx_queue);
715 	if (skb != NULL) {
716 		sk = skb->sk;
717 		llcp_sock = nfc_llcp_sock(sk);
718 
719 		if (llcp_sock == NULL && nfc_llcp_ptype(skb) == LLCP_PDU_I) {
720 			kfree_skb(skb);
721 			nfc_llcp_send_symm(local->dev);
722 		} else if (llcp_sock && !llcp_sock->remote_ready) {
723 			skb_queue_head(&local->tx_queue, skb);
724 			nfc_llcp_send_symm(local->dev);
725 		} else {
726 			struct sk_buff *copy_skb = NULL;
727 			u8 ptype = nfc_llcp_ptype(skb);
728 			int ret;
729 
730 			pr_debug("Sending pending skb\n");
731 			print_hex_dump(KERN_DEBUG, "LLCP Tx: ",
732 				       DUMP_PREFIX_OFFSET, 16, 1,
733 				       skb->data, skb->len, true);
734 
735 			if (ptype == LLCP_PDU_DISC && sk != NULL &&
736 			    sk->sk_state == LLCP_DISCONNECTING) {
737 				nfc_llcp_sock_unlink(&local->sockets, sk);
738 				sock_orphan(sk);
739 				sock_put(sk);
740 			}
741 
742 			if (ptype == LLCP_PDU_I)
743 				copy_skb = skb_copy(skb, GFP_ATOMIC);
744 
745 			__net_timestamp(skb);
746 
747 			nfc_llcp_send_to_raw_sock(local, skb,
748 						  NFC_LLCP_DIRECTION_TX);
749 
750 			ret = nfc_data_exchange(local->dev, local->target_idx,
751 						skb, nfc_llcp_recv, local);
752 
753 			if (ret) {
754 				kfree_skb(copy_skb);
755 				goto out;
756 			}
757 
758 			if (ptype == LLCP_PDU_I && copy_skb)
759 				skb_queue_tail(&llcp_sock->tx_pending_queue,
760 					       copy_skb);
761 		}
762 	} else {
763 		nfc_llcp_send_symm(local->dev);
764 	}
765 
766 out:
767 	mod_timer(&local->link_timer,
768 		  jiffies + msecs_to_jiffies(2 * local->remote_lto));
769 }
770 
771 static struct nfc_llcp_sock *nfc_llcp_connecting_sock_get(struct nfc_llcp_local *local,
772 							  u8 ssap)
773 {
774 	struct sock *sk;
775 	struct nfc_llcp_sock *llcp_sock;
776 
777 	read_lock(&local->connecting_sockets.lock);
778 
779 	sk_for_each(sk, &local->connecting_sockets.head) {
780 		llcp_sock = nfc_llcp_sock(sk);
781 
782 		if (llcp_sock->ssap == ssap) {
783 			sock_hold(&llcp_sock->sk);
784 			goto out;
785 		}
786 	}
787 
788 	llcp_sock = NULL;
789 
790 out:
791 	read_unlock(&local->connecting_sockets.lock);
792 
793 	return llcp_sock;
794 }
795 
796 static struct nfc_llcp_sock *nfc_llcp_sock_get_sn(struct nfc_llcp_local *local,
797 						  u8 *sn, size_t sn_len)
798 {
799 	struct nfc_llcp_sock *llcp_sock;
800 
801 	llcp_sock = nfc_llcp_sock_from_sn(local, sn, sn_len);
802 
803 	if (llcp_sock == NULL)
804 		return NULL;
805 
806 	sock_hold(&llcp_sock->sk);
807 
808 	return llcp_sock;
809 }
810 
811 static u8 *nfc_llcp_connect_sn(struct sk_buff *skb, size_t *sn_len)
812 {
813 	u8 *tlv = &skb->data[2], type, length;
814 	size_t tlv_array_len = skb->len - LLCP_HEADER_SIZE, offset = 0;
815 
816 	while (offset < tlv_array_len) {
817 		type = tlv[0];
818 		length = tlv[1];
819 
820 		pr_debug("type 0x%x length %d\n", type, length);
821 
822 		if (type == LLCP_TLV_SN) {
823 			*sn_len = length;
824 			return &tlv[2];
825 		}
826 
827 		offset += length + 2;
828 		tlv += length + 2;
829 	}
830 
831 	return NULL;
832 }
833 
834 static void nfc_llcp_recv_ui(struct nfc_llcp_local *local,
835 			     struct sk_buff *skb)
836 {
837 	struct nfc_llcp_sock *llcp_sock;
838 	struct nfc_llcp_ui_cb *ui_cb;
839 	u8 dsap, ssap;
840 
841 	dsap = nfc_llcp_dsap(skb);
842 	ssap = nfc_llcp_ssap(skb);
843 
844 	ui_cb = nfc_llcp_ui_skb_cb(skb);
845 	ui_cb->dsap = dsap;
846 	ui_cb->ssap = ssap;
847 
848 	pr_debug("%d %d\n", dsap, ssap);
849 
850 	/* We're looking for a bound socket, not a client one */
851 	llcp_sock = nfc_llcp_sock_get(local, dsap, LLCP_SAP_SDP);
852 	if (llcp_sock == NULL || llcp_sock->sk.sk_type != SOCK_DGRAM)
853 		return;
854 
855 	/* There is no sequence with UI frames */
856 	skb_pull(skb, LLCP_HEADER_SIZE);
857 	if (!sock_queue_rcv_skb(&llcp_sock->sk, skb)) {
858 		/*
859 		 * UI frames will be freed from the socket layer, so we
860 		 * need to keep them alive until someone receives them.
861 		 */
862 		skb_get(skb);
863 	} else {
864 		pr_err("Receive queue is full\n");
865 	}
866 
867 	nfc_llcp_sock_put(llcp_sock);
868 }
869 
870 static void nfc_llcp_recv_connect(struct nfc_llcp_local *local,
871 				  struct sk_buff *skb)
872 {
873 	struct sock *new_sk, *parent;
874 	struct nfc_llcp_sock *sock, *new_sock;
875 	u8 dsap, ssap, reason;
876 
877 	dsap = nfc_llcp_dsap(skb);
878 	ssap = nfc_llcp_ssap(skb);
879 
880 	pr_debug("%d %d\n", dsap, ssap);
881 
882 	if (dsap != LLCP_SAP_SDP) {
883 		sock = nfc_llcp_sock_get(local, dsap, LLCP_SAP_SDP);
884 		if (sock == NULL || sock->sk.sk_state != LLCP_LISTEN) {
885 			reason = LLCP_DM_NOBOUND;
886 			goto fail;
887 		}
888 	} else {
889 		u8 *sn;
890 		size_t sn_len;
891 
892 		sn = nfc_llcp_connect_sn(skb, &sn_len);
893 		if (sn == NULL) {
894 			reason = LLCP_DM_NOBOUND;
895 			goto fail;
896 		}
897 
898 		pr_debug("Service name length %zu\n", sn_len);
899 
900 		sock = nfc_llcp_sock_get_sn(local, sn, sn_len);
901 		if (sock == NULL) {
902 			reason = LLCP_DM_NOBOUND;
903 			goto fail;
904 		}
905 	}
906 
907 	lock_sock(&sock->sk);
908 
909 	parent = &sock->sk;
910 
911 	if (sk_acceptq_is_full(parent)) {
912 		reason = LLCP_DM_REJ;
913 		release_sock(&sock->sk);
914 		sock_put(&sock->sk);
915 		goto fail;
916 	}
917 
918 	if (sock->ssap == LLCP_SDP_UNBOUND) {
919 		u8 ssap = nfc_llcp_reserve_sdp_ssap(local);
920 
921 		pr_debug("First client, reserving %d\n", ssap);
922 
923 		if (ssap == LLCP_SAP_MAX) {
924 			reason = LLCP_DM_REJ;
925 			release_sock(&sock->sk);
926 			sock_put(&sock->sk);
927 			goto fail;
928 		}
929 
930 		sock->ssap = ssap;
931 	}
932 
933 	new_sk = nfc_llcp_sock_alloc(NULL, parent->sk_type, GFP_ATOMIC);
934 	if (new_sk == NULL) {
935 		reason = LLCP_DM_REJ;
936 		release_sock(&sock->sk);
937 		sock_put(&sock->sk);
938 		goto fail;
939 	}
940 
941 	new_sock = nfc_llcp_sock(new_sk);
942 	new_sock->dev = local->dev;
943 	new_sock->local = nfc_llcp_local_get(local);
944 	new_sock->rw = sock->rw;
945 	new_sock->miux = sock->miux;
946 	new_sock->remote_miu = local->remote_miu;
947 	new_sock->nfc_protocol = sock->nfc_protocol;
948 	new_sock->dsap = ssap;
949 	new_sock->target_idx = local->target_idx;
950 	new_sock->parent = parent;
951 	new_sock->ssap = sock->ssap;
952 	if (sock->ssap < LLCP_LOCAL_NUM_SAP && sock->ssap >= LLCP_WKS_NUM_SAP) {
953 		atomic_t *client_count;
954 
955 		pr_debug("reserved_ssap %d for %p\n", sock->ssap, new_sock);
956 
957 		client_count =
958 			&local->local_sdp_cnt[sock->ssap - LLCP_WKS_NUM_SAP];
959 
960 		atomic_inc(client_count);
961 		new_sock->reserved_ssap = sock->ssap;
962 	}
963 
964 	nfc_llcp_parse_connection_tlv(new_sock, &skb->data[LLCP_HEADER_SIZE],
965 				      skb->len - LLCP_HEADER_SIZE);
966 
967 	pr_debug("new sock %p sk %p\n", new_sock, &new_sock->sk);
968 
969 	nfc_llcp_sock_link(&local->sockets, new_sk);
970 
971 	nfc_llcp_accept_enqueue(&sock->sk, new_sk);
972 
973 	nfc_get_device(local->dev->idx);
974 
975 	new_sk->sk_state = LLCP_CONNECTED;
976 
977 	/* Wake the listening processes */
978 	parent->sk_data_ready(parent, 0);
979 
980 	/* Send CC */
981 	nfc_llcp_send_cc(new_sock);
982 
983 	release_sock(&sock->sk);
984 	sock_put(&sock->sk);
985 
986 	return;
987 
988 fail:
989 	/* Send DM */
990 	nfc_llcp_send_dm(local, dsap, ssap, reason);
991 }
992 
993 int nfc_llcp_queue_i_frames(struct nfc_llcp_sock *sock)
994 {
995 	int nr_frames = 0;
996 	struct nfc_llcp_local *local = sock->local;
997 
998 	pr_debug("Remote ready %d tx queue len %d remote rw %d",
999 		 sock->remote_ready, skb_queue_len(&sock->tx_pending_queue),
1000 		 sock->remote_rw);
1001 
1002 	/* Try to queue some I frames for transmission */
1003 	while (sock->remote_ready &&
1004 	       skb_queue_len(&sock->tx_pending_queue) < sock->remote_rw) {
1005 		struct sk_buff *pdu;
1006 
1007 		pdu = skb_dequeue(&sock->tx_queue);
1008 		if (pdu == NULL)
1009 			break;
1010 
1011 		/* Update N(S)/N(R) */
1012 		nfc_llcp_set_nrns(sock, pdu);
1013 
1014 		skb_queue_tail(&local->tx_queue, pdu);
1015 		nr_frames++;
1016 	}
1017 
1018 	return nr_frames;
1019 }
1020 
1021 static void nfc_llcp_recv_hdlc(struct nfc_llcp_local *local,
1022 			       struct sk_buff *skb)
1023 {
1024 	struct nfc_llcp_sock *llcp_sock;
1025 	struct sock *sk;
1026 	u8 dsap, ssap, ptype, ns, nr;
1027 
1028 	ptype = nfc_llcp_ptype(skb);
1029 	dsap = nfc_llcp_dsap(skb);
1030 	ssap = nfc_llcp_ssap(skb);
1031 	ns = nfc_llcp_ns(skb);
1032 	nr = nfc_llcp_nr(skb);
1033 
1034 	pr_debug("%d %d R %d S %d\n", dsap, ssap, nr, ns);
1035 
1036 	llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
1037 	if (llcp_sock == NULL) {
1038 		nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);
1039 		return;
1040 	}
1041 
1042 	sk = &llcp_sock->sk;
1043 	lock_sock(sk);
1044 	if (sk->sk_state == LLCP_CLOSED) {
1045 		release_sock(sk);
1046 		nfc_llcp_sock_put(llcp_sock);
1047 	}
1048 
1049 	/* Pass the payload upstream */
1050 	if (ptype == LLCP_PDU_I) {
1051 		pr_debug("I frame, queueing on %p\n", &llcp_sock->sk);
1052 
1053 		if (ns == llcp_sock->recv_n)
1054 			llcp_sock->recv_n = (llcp_sock->recv_n + 1) % 16;
1055 		else
1056 			pr_err("Received out of sequence I PDU\n");
1057 
1058 		skb_pull(skb, LLCP_HEADER_SIZE + LLCP_SEQUENCE_SIZE);
1059 		if (!sock_queue_rcv_skb(&llcp_sock->sk, skb)) {
1060 			/*
1061 			 * I frames will be freed from the socket layer, so we
1062 			 * need to keep them alive until someone receives them.
1063 			 */
1064 			skb_get(skb);
1065 		} else {
1066 			pr_err("Receive queue is full\n");
1067 		}
1068 	}
1069 
1070 	/* Remove skbs from the pending queue */
1071 	if (llcp_sock->send_ack_n != nr) {
1072 		struct sk_buff *s, *tmp;
1073 		u8 n;
1074 
1075 		llcp_sock->send_ack_n = nr;
1076 
1077 		/* Remove and free all skbs until ns == nr */
1078 		skb_queue_walk_safe(&llcp_sock->tx_pending_queue, s, tmp) {
1079 			n = nfc_llcp_ns(s);
1080 
1081 			skb_unlink(s, &llcp_sock->tx_pending_queue);
1082 			kfree_skb(s);
1083 
1084 			if (n == nr)
1085 				break;
1086 		}
1087 
1088 		/* Re-queue the remaining skbs for transmission */
1089 		skb_queue_reverse_walk_safe(&llcp_sock->tx_pending_queue,
1090 					    s, tmp) {
1091 			skb_unlink(s, &llcp_sock->tx_pending_queue);
1092 			skb_queue_head(&local->tx_queue, s);
1093 		}
1094 	}
1095 
1096 	if (ptype == LLCP_PDU_RR)
1097 		llcp_sock->remote_ready = true;
1098 	else if (ptype == LLCP_PDU_RNR)
1099 		llcp_sock->remote_ready = false;
1100 
1101 	if (nfc_llcp_queue_i_frames(llcp_sock) == 0 && ptype == LLCP_PDU_I)
1102 		nfc_llcp_send_rr(llcp_sock);
1103 
1104 	release_sock(sk);
1105 	nfc_llcp_sock_put(llcp_sock);
1106 }
1107 
1108 static void nfc_llcp_recv_disc(struct nfc_llcp_local *local,
1109 			       struct sk_buff *skb)
1110 {
1111 	struct nfc_llcp_sock *llcp_sock;
1112 	struct sock *sk;
1113 	u8 dsap, ssap;
1114 
1115 	dsap = nfc_llcp_dsap(skb);
1116 	ssap = nfc_llcp_ssap(skb);
1117 
1118 	if ((dsap == 0) && (ssap == 0)) {
1119 		pr_debug("Connection termination");
1120 		nfc_dep_link_down(local->dev);
1121 		return;
1122 	}
1123 
1124 	llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
1125 	if (llcp_sock == NULL) {
1126 		nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);
1127 		return;
1128 	}
1129 
1130 	sk = &llcp_sock->sk;
1131 	lock_sock(sk);
1132 
1133 	nfc_llcp_socket_purge(llcp_sock);
1134 
1135 	if (sk->sk_state == LLCP_CLOSED) {
1136 		release_sock(sk);
1137 		nfc_llcp_sock_put(llcp_sock);
1138 	}
1139 
1140 	if (sk->sk_state == LLCP_CONNECTED) {
1141 		nfc_put_device(local->dev);
1142 		sk->sk_state = LLCP_CLOSED;
1143 		sk->sk_state_change(sk);
1144 	}
1145 
1146 	nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_DISC);
1147 
1148 	release_sock(sk);
1149 	nfc_llcp_sock_put(llcp_sock);
1150 }
1151 
1152 static void nfc_llcp_recv_cc(struct nfc_llcp_local *local, struct sk_buff *skb)
1153 {
1154 	struct nfc_llcp_sock *llcp_sock;
1155 	struct sock *sk;
1156 	u8 dsap, ssap;
1157 
1158 	dsap = nfc_llcp_dsap(skb);
1159 	ssap = nfc_llcp_ssap(skb);
1160 
1161 	llcp_sock = nfc_llcp_connecting_sock_get(local, dsap);
1162 	if (llcp_sock == NULL) {
1163 		pr_err("Invalid CC\n");
1164 		nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);
1165 
1166 		return;
1167 	}
1168 
1169 	sk = &llcp_sock->sk;
1170 
1171 	/* Unlink from connecting and link to the client array */
1172 	nfc_llcp_sock_unlink(&local->connecting_sockets, sk);
1173 	nfc_llcp_sock_link(&local->sockets, sk);
1174 	llcp_sock->dsap = ssap;
1175 
1176 	nfc_llcp_parse_connection_tlv(llcp_sock, &skb->data[LLCP_HEADER_SIZE],
1177 				      skb->len - LLCP_HEADER_SIZE);
1178 
1179 	sk->sk_state = LLCP_CONNECTED;
1180 	sk->sk_state_change(sk);
1181 
1182 	nfc_llcp_sock_put(llcp_sock);
1183 }
1184 
1185 static void nfc_llcp_recv_dm(struct nfc_llcp_local *local, struct sk_buff *skb)
1186 {
1187 	struct nfc_llcp_sock *llcp_sock;
1188 	struct sock *sk;
1189 	u8 dsap, ssap, reason;
1190 
1191 	dsap = nfc_llcp_dsap(skb);
1192 	ssap = nfc_llcp_ssap(skb);
1193 	reason = skb->data[2];
1194 
1195 	pr_debug("%d %d reason %d\n", ssap, dsap, reason);
1196 
1197 	switch (reason) {
1198 	case LLCP_DM_NOBOUND:
1199 	case LLCP_DM_REJ:
1200 		llcp_sock = nfc_llcp_connecting_sock_get(local, dsap);
1201 		break;
1202 
1203 	default:
1204 		llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
1205 		break;
1206 	}
1207 
1208 	if (llcp_sock == NULL) {
1209 		pr_debug("Already closed\n");
1210 		return;
1211 	}
1212 
1213 	sk = &llcp_sock->sk;
1214 
1215 	sk->sk_err = ENXIO;
1216 	sk->sk_state = LLCP_CLOSED;
1217 	sk->sk_state_change(sk);
1218 
1219 	nfc_llcp_sock_put(llcp_sock);
1220 }
1221 
1222 static void nfc_llcp_recv_snl(struct nfc_llcp_local *local,
1223 			      struct sk_buff *skb)
1224 {
1225 	struct nfc_llcp_sock *llcp_sock;
1226 	u8 dsap, ssap, *tlv, type, length, tid, sap;
1227 	u16 tlv_len, offset;
1228 	char *service_name;
1229 	size_t service_name_len;
1230 	struct nfc_llcp_sdp_tlv *sdp;
1231 	HLIST_HEAD(llc_sdres_list);
1232 	size_t sdres_tlvs_len;
1233 	HLIST_HEAD(nl_sdres_list);
1234 
1235 	dsap = nfc_llcp_dsap(skb);
1236 	ssap = nfc_llcp_ssap(skb);
1237 
1238 	pr_debug("%d %d\n", dsap, ssap);
1239 
1240 	if (dsap != LLCP_SAP_SDP || ssap != LLCP_SAP_SDP) {
1241 		pr_err("Wrong SNL SAP\n");
1242 		return;
1243 	}
1244 
1245 	tlv = &skb->data[LLCP_HEADER_SIZE];
1246 	tlv_len = skb->len - LLCP_HEADER_SIZE;
1247 	offset = 0;
1248 	sdres_tlvs_len = 0;
1249 
1250 	while (offset < tlv_len) {
1251 		type = tlv[0];
1252 		length = tlv[1];
1253 
1254 		switch (type) {
1255 		case LLCP_TLV_SDREQ:
1256 			tid = tlv[2];
1257 			service_name = (char *) &tlv[3];
1258 			service_name_len = length - 1;
1259 
1260 			pr_debug("Looking for %.16s\n", service_name);
1261 
1262 			if (service_name_len == strlen("urn:nfc:sn:sdp") &&
1263 			    !strncmp(service_name, "urn:nfc:sn:sdp",
1264 				     service_name_len)) {
1265 				sap = 1;
1266 				goto add_snl;
1267 			}
1268 
1269 			llcp_sock = nfc_llcp_sock_from_sn(local, service_name,
1270 							  service_name_len);
1271 			if (!llcp_sock) {
1272 				sap = 0;
1273 				goto add_snl;
1274 			}
1275 
1276 			/*
1277 			 * We found a socket but its ssap has not been reserved
1278 			 * yet. We need to assign it for good and send a reply.
1279 			 * The ssap will be freed when the socket is closed.
1280 			 */
1281 			if (llcp_sock->ssap == LLCP_SDP_UNBOUND) {
1282 				atomic_t *client_count;
1283 
1284 				sap = nfc_llcp_reserve_sdp_ssap(local);
1285 
1286 				pr_debug("Reserving %d\n", sap);
1287 
1288 				if (sap == LLCP_SAP_MAX) {
1289 					sap = 0;
1290 					goto add_snl;
1291 				}
1292 
1293 				client_count =
1294 					&local->local_sdp_cnt[sap -
1295 							      LLCP_WKS_NUM_SAP];
1296 
1297 				atomic_inc(client_count);
1298 
1299 				llcp_sock->ssap = sap;
1300 				llcp_sock->reserved_ssap = sap;
1301 			} else {
1302 				sap = llcp_sock->ssap;
1303 			}
1304 
1305 			pr_debug("%p %d\n", llcp_sock, sap);
1306 
1307 add_snl:
1308 			sdp = nfc_llcp_build_sdres_tlv(tid, sap);
1309 			if (sdp == NULL)
1310 				goto exit;
1311 
1312 			sdres_tlvs_len += sdp->tlv_len;
1313 			hlist_add_head(&sdp->node, &llc_sdres_list);
1314 			break;
1315 
1316 		case LLCP_TLV_SDRES:
1317 			mutex_lock(&local->sdreq_lock);
1318 
1319 			pr_debug("LLCP_TLV_SDRES: searching tid %d\n", tlv[2]);
1320 
1321 			hlist_for_each_entry(sdp, &local->pending_sdreqs, node) {
1322 				if (sdp->tid != tlv[2])
1323 					continue;
1324 
1325 				sdp->sap = tlv[3];
1326 
1327 				pr_debug("Found: uri=%s, sap=%d\n",
1328 					 sdp->uri, sdp->sap);
1329 
1330 				hlist_del(&sdp->node);
1331 
1332 				hlist_add_head(&sdp->node, &nl_sdres_list);
1333 
1334 				break;
1335 			}
1336 
1337 			mutex_unlock(&local->sdreq_lock);
1338 			break;
1339 
1340 		default:
1341 			pr_err("Invalid SNL tlv value 0x%x\n", type);
1342 			break;
1343 		}
1344 
1345 		offset += length + 2;
1346 		tlv += length + 2;
1347 	}
1348 
1349 exit:
1350 	if (!hlist_empty(&nl_sdres_list))
1351 		nfc_genl_llc_send_sdres(local->dev, &nl_sdres_list);
1352 
1353 	if (!hlist_empty(&llc_sdres_list))
1354 		nfc_llcp_send_snl_sdres(local, &llc_sdres_list, sdres_tlvs_len);
1355 }
1356 
1357 static void nfc_llcp_recv_agf(struct nfc_llcp_local *local, struct sk_buff *skb)
1358 {
1359 	u8 ptype;
1360 	u16 pdu_len;
1361 	struct sk_buff *new_skb;
1362 
1363 	if (skb->len <= LLCP_HEADER_SIZE) {
1364 		pr_err("Malformed AGF PDU\n");
1365 		return;
1366 	}
1367 
1368 	skb_pull(skb, LLCP_HEADER_SIZE);
1369 
1370 	while (skb->len > LLCP_AGF_PDU_HEADER_SIZE) {
1371 		pdu_len = skb->data[0] << 8 | skb->data[1];
1372 
1373 		skb_pull(skb, LLCP_AGF_PDU_HEADER_SIZE);
1374 
1375 		if (pdu_len < LLCP_HEADER_SIZE || pdu_len > skb->len) {
1376 			pr_err("Malformed AGF PDU\n");
1377 			return;
1378 		}
1379 
1380 		ptype = nfc_llcp_ptype(skb);
1381 
1382 		if (ptype == LLCP_PDU_SYMM || ptype == LLCP_PDU_AGF)
1383 			goto next;
1384 
1385 		new_skb = nfc_alloc_recv_skb(pdu_len, GFP_KERNEL);
1386 		if (new_skb == NULL) {
1387 			pr_err("Could not allocate PDU\n");
1388 			return;
1389 		}
1390 
1391 		memcpy(skb_put(new_skb, pdu_len), skb->data, pdu_len);
1392 
1393 		nfc_llcp_rx_skb(local, new_skb);
1394 
1395 		kfree_skb(new_skb);
1396 next:
1397 		skb_pull(skb, pdu_len);
1398 	}
1399 }
1400 
1401 static void nfc_llcp_rx_skb(struct nfc_llcp_local *local, struct sk_buff *skb)
1402 {
1403 	u8 dsap, ssap, ptype;
1404 
1405 	ptype = nfc_llcp_ptype(skb);
1406 	dsap = nfc_llcp_dsap(skb);
1407 	ssap = nfc_llcp_ssap(skb);
1408 
1409 	pr_debug("ptype 0x%x dsap 0x%x ssap 0x%x\n", ptype, dsap, ssap);
1410 
1411 	if (ptype != LLCP_PDU_SYMM)
1412 		print_hex_dump(KERN_DEBUG, "LLCP Rx: ", DUMP_PREFIX_OFFSET,
1413 			       16, 1, skb->data, skb->len, true);
1414 
1415 	switch (ptype) {
1416 	case LLCP_PDU_SYMM:
1417 		pr_debug("SYMM\n");
1418 		break;
1419 
1420 	case LLCP_PDU_UI:
1421 		pr_debug("UI\n");
1422 		nfc_llcp_recv_ui(local, skb);
1423 		break;
1424 
1425 	case LLCP_PDU_CONNECT:
1426 		pr_debug("CONNECT\n");
1427 		nfc_llcp_recv_connect(local, skb);
1428 		break;
1429 
1430 	case LLCP_PDU_DISC:
1431 		pr_debug("DISC\n");
1432 		nfc_llcp_recv_disc(local, skb);
1433 		break;
1434 
1435 	case LLCP_PDU_CC:
1436 		pr_debug("CC\n");
1437 		nfc_llcp_recv_cc(local, skb);
1438 		break;
1439 
1440 	case LLCP_PDU_DM:
1441 		pr_debug("DM\n");
1442 		nfc_llcp_recv_dm(local, skb);
1443 		break;
1444 
1445 	case LLCP_PDU_SNL:
1446 		pr_debug("SNL\n");
1447 		nfc_llcp_recv_snl(local, skb);
1448 		break;
1449 
1450 	case LLCP_PDU_I:
1451 	case LLCP_PDU_RR:
1452 	case LLCP_PDU_RNR:
1453 		pr_debug("I frame\n");
1454 		nfc_llcp_recv_hdlc(local, skb);
1455 		break;
1456 
1457 	case LLCP_PDU_AGF:
1458 		pr_debug("AGF frame\n");
1459 		nfc_llcp_recv_agf(local, skb);
1460 		break;
1461 	}
1462 }
1463 
1464 static void nfc_llcp_rx_work(struct work_struct *work)
1465 {
1466 	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
1467 						    rx_work);
1468 	struct sk_buff *skb;
1469 
1470 	skb = local->rx_pending;
1471 	if (skb == NULL) {
1472 		pr_debug("No pending SKB\n");
1473 		return;
1474 	}
1475 
1476 	__net_timestamp(skb);
1477 
1478 	nfc_llcp_send_to_raw_sock(local, skb, NFC_LLCP_DIRECTION_RX);
1479 
1480 	nfc_llcp_rx_skb(local, skb);
1481 
1482 	schedule_work(&local->tx_work);
1483 	kfree_skb(local->rx_pending);
1484 	local->rx_pending = NULL;
1485 }
1486 
1487 static void __nfc_llcp_recv(struct nfc_llcp_local *local, struct sk_buff *skb)
1488 {
1489 	local->rx_pending = skb;
1490 	del_timer(&local->link_timer);
1491 	schedule_work(&local->rx_work);
1492 }
1493 
1494 void nfc_llcp_recv(void *data, struct sk_buff *skb, int err)
1495 {
1496 	struct nfc_llcp_local *local = (struct nfc_llcp_local *) data;
1497 
1498 	pr_debug("Received an LLCP PDU\n");
1499 	if (err < 0) {
1500 		pr_err("err %d\n", err);
1501 		return;
1502 	}
1503 
1504 	__nfc_llcp_recv(local, skb);
1505 }
1506 
1507 int nfc_llcp_data_received(struct nfc_dev *dev, struct sk_buff *skb)
1508 {
1509 	struct nfc_llcp_local *local;
1510 
1511 	local = nfc_llcp_find_local(dev);
1512 	if (local == NULL)
1513 		return -ENODEV;
1514 
1515 	__nfc_llcp_recv(local, skb);
1516 
1517 	return 0;
1518 }
1519 
1520 void nfc_llcp_mac_is_down(struct nfc_dev *dev)
1521 {
1522 	struct nfc_llcp_local *local;
1523 
1524 	local = nfc_llcp_find_local(dev);
1525 	if (local == NULL)
1526 		return;
1527 
1528 	local->remote_miu = LLCP_DEFAULT_MIU;
1529 	local->remote_lto = LLCP_DEFAULT_LTO;
1530 
1531 	/* Close and purge all existing sockets */
1532 	nfc_llcp_socket_release(local, true, 0);
1533 }
1534 
1535 void nfc_llcp_mac_is_up(struct nfc_dev *dev, u32 target_idx,
1536 			u8 comm_mode, u8 rf_mode)
1537 {
1538 	struct nfc_llcp_local *local;
1539 
1540 	pr_debug("rf mode %d\n", rf_mode);
1541 
1542 	local = nfc_llcp_find_local(dev);
1543 	if (local == NULL)
1544 		return;
1545 
1546 	local->target_idx = target_idx;
1547 	local->comm_mode = comm_mode;
1548 	local->rf_mode = rf_mode;
1549 
1550 	if (rf_mode == NFC_RF_INITIATOR) {
1551 		pr_debug("Queueing Tx work\n");
1552 
1553 		schedule_work(&local->tx_work);
1554 	} else {
1555 		mod_timer(&local->link_timer,
1556 			  jiffies + msecs_to_jiffies(local->remote_lto));
1557 	}
1558 }
1559 
1560 int nfc_llcp_register_device(struct nfc_dev *ndev)
1561 {
1562 	struct nfc_llcp_local *local;
1563 
1564 	local = kzalloc(sizeof(struct nfc_llcp_local), GFP_KERNEL);
1565 	if (local == NULL)
1566 		return -ENOMEM;
1567 
1568 	local->dev = ndev;
1569 	INIT_LIST_HEAD(&local->list);
1570 	kref_init(&local->ref);
1571 	mutex_init(&local->sdp_lock);
1572 	init_timer(&local->link_timer);
1573 	local->link_timer.data = (unsigned long) local;
1574 	local->link_timer.function = nfc_llcp_symm_timer;
1575 
1576 	skb_queue_head_init(&local->tx_queue);
1577 	INIT_WORK(&local->tx_work, nfc_llcp_tx_work);
1578 
1579 	local->rx_pending = NULL;
1580 	INIT_WORK(&local->rx_work, nfc_llcp_rx_work);
1581 
1582 	INIT_WORK(&local->timeout_work, nfc_llcp_timeout_work);
1583 
1584 	rwlock_init(&local->sockets.lock);
1585 	rwlock_init(&local->connecting_sockets.lock);
1586 	rwlock_init(&local->raw_sockets.lock);
1587 
1588 	local->lto = 150; /* 1500 ms */
1589 	local->rw = LLCP_MAX_RW;
1590 	local->miux = cpu_to_be16(LLCP_MAX_MIUX);
1591 	local->local_wks = 0x1; /* LLC Link Management */
1592 
1593 	nfc_llcp_build_gb(local);
1594 
1595 	local->remote_miu = LLCP_DEFAULT_MIU;
1596 	local->remote_lto = LLCP_DEFAULT_LTO;
1597 
1598 	mutex_init(&local->sdreq_lock);
1599 	INIT_HLIST_HEAD(&local->pending_sdreqs);
1600 	init_timer(&local->sdreq_timer);
1601 	local->sdreq_timer.data = (unsigned long) local;
1602 	local->sdreq_timer.function = nfc_llcp_sdreq_timer;
1603 	INIT_WORK(&local->sdreq_timeout_work, nfc_llcp_sdreq_timeout_work);
1604 
1605 	list_add(&local->list, &llcp_devices);
1606 
1607 	return 0;
1608 }
1609 
1610 void nfc_llcp_unregister_device(struct nfc_dev *dev)
1611 {
1612 	struct nfc_llcp_local *local = nfc_llcp_find_local(dev);
1613 
1614 	if (local == NULL) {
1615 		pr_debug("No such device\n");
1616 		return;
1617 	}
1618 
1619 	local_cleanup(local);
1620 
1621 	nfc_llcp_local_put(local);
1622 }
1623 
1624 int __init nfc_llcp_init(void)
1625 {
1626 	INIT_LIST_HEAD(&llcp_devices);
1627 
1628 	return nfc_llcp_sock_init();
1629 }
1630 
1631 void nfc_llcp_exit(void)
1632 {
1633 	nfc_llcp_sock_exit();
1634 }
1635