xref: /openbmc/linux/net/nfc/llcp_core.c (revision 8dde5715)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2011  Intel Corporation. All rights reserved.
4  * Copyright (C) 2014 Marvell International Ltd.
5  */
6 
7 #define pr_fmt(fmt) "llcp: %s: " fmt, __func__
8 
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/list.h>
12 #include <linux/nfc.h>
13 
14 #include "nfc.h"
15 #include "llcp.h"
16 
17 static u8 llcp_magic[3] = {0x46, 0x66, 0x6d};
18 
19 static LIST_HEAD(llcp_devices);
20 
21 static void nfc_llcp_rx_skb(struct nfc_llcp_local *local, struct sk_buff *skb);
22 
23 void nfc_llcp_sock_link(struct llcp_sock_list *l, struct sock *sk)
24 {
25 	write_lock(&l->lock);
26 	sk_add_node(sk, &l->head);
27 	write_unlock(&l->lock);
28 }
29 
30 void nfc_llcp_sock_unlink(struct llcp_sock_list *l, struct sock *sk)
31 {
32 	write_lock(&l->lock);
33 	sk_del_node_init(sk);
34 	write_unlock(&l->lock);
35 }
36 
37 void nfc_llcp_socket_remote_param_init(struct nfc_llcp_sock *sock)
38 {
39 	sock->remote_rw = LLCP_DEFAULT_RW;
40 	sock->remote_miu = LLCP_MAX_MIU + 1;
41 }
42 
43 static void nfc_llcp_socket_purge(struct nfc_llcp_sock *sock)
44 {
45 	struct nfc_llcp_local *local = sock->local;
46 	struct sk_buff *s, *tmp;
47 
48 	pr_debug("%p\n", &sock->sk);
49 
50 	skb_queue_purge(&sock->tx_queue);
51 	skb_queue_purge(&sock->tx_pending_queue);
52 
53 	if (local == NULL)
54 		return;
55 
56 	/* Search for local pending SKBs that are related to this socket */
57 	skb_queue_walk_safe(&local->tx_queue, s, tmp) {
58 		if (s->sk != &sock->sk)
59 			continue;
60 
61 		skb_unlink(s, &local->tx_queue);
62 		kfree_skb(s);
63 	}
64 }
65 
66 static void nfc_llcp_socket_release(struct nfc_llcp_local *local, bool device,
67 				    int err)
68 {
69 	struct sock *sk;
70 	struct hlist_node *tmp;
71 	struct nfc_llcp_sock *llcp_sock;
72 
73 	skb_queue_purge(&local->tx_queue);
74 
75 	write_lock(&local->sockets.lock);
76 
77 	sk_for_each_safe(sk, tmp, &local->sockets.head) {
78 		llcp_sock = nfc_llcp_sock(sk);
79 
80 		bh_lock_sock(sk);
81 
82 		nfc_llcp_socket_purge(llcp_sock);
83 
84 		if (sk->sk_state == LLCP_CONNECTED)
85 			nfc_put_device(llcp_sock->dev);
86 
87 		if (sk->sk_state == LLCP_LISTEN) {
88 			struct nfc_llcp_sock *lsk, *n;
89 			struct sock *accept_sk;
90 
91 			list_for_each_entry_safe(lsk, n,
92 						 &llcp_sock->accept_queue,
93 						 accept_queue) {
94 				accept_sk = &lsk->sk;
95 				bh_lock_sock(accept_sk);
96 
97 				nfc_llcp_accept_unlink(accept_sk);
98 
99 				if (err)
100 					accept_sk->sk_err = err;
101 				accept_sk->sk_state = LLCP_CLOSED;
102 				accept_sk->sk_state_change(sk);
103 
104 				bh_unlock_sock(accept_sk);
105 			}
106 		}
107 
108 		if (err)
109 			sk->sk_err = err;
110 		sk->sk_state = LLCP_CLOSED;
111 		sk->sk_state_change(sk);
112 
113 		bh_unlock_sock(sk);
114 
115 		sk_del_node_init(sk);
116 	}
117 
118 	write_unlock(&local->sockets.lock);
119 
120 	/* If we still have a device, we keep the RAW sockets alive */
121 	if (device == true)
122 		return;
123 
124 	write_lock(&local->raw_sockets.lock);
125 
126 	sk_for_each_safe(sk, tmp, &local->raw_sockets.head) {
127 		llcp_sock = nfc_llcp_sock(sk);
128 
129 		bh_lock_sock(sk);
130 
131 		nfc_llcp_socket_purge(llcp_sock);
132 
133 		if (err)
134 			sk->sk_err = err;
135 		sk->sk_state = LLCP_CLOSED;
136 		sk->sk_state_change(sk);
137 
138 		bh_unlock_sock(sk);
139 
140 		sk_del_node_init(sk);
141 	}
142 
143 	write_unlock(&local->raw_sockets.lock);
144 }
145 
146 struct nfc_llcp_local *nfc_llcp_local_get(struct nfc_llcp_local *local)
147 {
148 	kref_get(&local->ref);
149 
150 	return local;
151 }
152 
153 static void local_cleanup(struct nfc_llcp_local *local)
154 {
155 	nfc_llcp_socket_release(local, false, ENXIO);
156 	del_timer_sync(&local->link_timer);
157 	skb_queue_purge(&local->tx_queue);
158 	cancel_work_sync(&local->tx_work);
159 	cancel_work_sync(&local->rx_work);
160 	cancel_work_sync(&local->timeout_work);
161 	kfree_skb(local->rx_pending);
162 	del_timer_sync(&local->sdreq_timer);
163 	cancel_work_sync(&local->sdreq_timeout_work);
164 	nfc_llcp_free_sdp_tlv_list(&local->pending_sdreqs);
165 }
166 
167 static void local_release(struct kref *ref)
168 {
169 	struct nfc_llcp_local *local;
170 
171 	local = container_of(ref, struct nfc_llcp_local, ref);
172 
173 	list_del(&local->list);
174 	local_cleanup(local);
175 	kfree(local);
176 }
177 
178 int nfc_llcp_local_put(struct nfc_llcp_local *local)
179 {
180 	if (local == NULL)
181 		return 0;
182 
183 	return kref_put(&local->ref, local_release);
184 }
185 
186 static struct nfc_llcp_sock *nfc_llcp_sock_get(struct nfc_llcp_local *local,
187 					       u8 ssap, u8 dsap)
188 {
189 	struct sock *sk;
190 	struct nfc_llcp_sock *llcp_sock, *tmp_sock;
191 
192 	pr_debug("ssap dsap %d %d\n", ssap, dsap);
193 
194 	if (ssap == 0 && dsap == 0)
195 		return NULL;
196 
197 	read_lock(&local->sockets.lock);
198 
199 	llcp_sock = NULL;
200 
201 	sk_for_each(sk, &local->sockets.head) {
202 		tmp_sock = nfc_llcp_sock(sk);
203 
204 		if (tmp_sock->ssap == ssap && tmp_sock->dsap == dsap) {
205 			llcp_sock = tmp_sock;
206 			break;
207 		}
208 	}
209 
210 	read_unlock(&local->sockets.lock);
211 
212 	if (llcp_sock == NULL)
213 		return NULL;
214 
215 	sock_hold(&llcp_sock->sk);
216 
217 	return llcp_sock;
218 }
219 
220 static void nfc_llcp_sock_put(struct nfc_llcp_sock *sock)
221 {
222 	sock_put(&sock->sk);
223 }
224 
225 static void nfc_llcp_timeout_work(struct work_struct *work)
226 {
227 	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
228 						    timeout_work);
229 
230 	nfc_dep_link_down(local->dev);
231 }
232 
233 static void nfc_llcp_symm_timer(struct timer_list *t)
234 {
235 	struct nfc_llcp_local *local = from_timer(local, t, link_timer);
236 
237 	pr_err("SYMM timeout\n");
238 
239 	schedule_work(&local->timeout_work);
240 }
241 
242 static void nfc_llcp_sdreq_timeout_work(struct work_struct *work)
243 {
244 	unsigned long time;
245 	HLIST_HEAD(nl_sdres_list);
246 	struct hlist_node *n;
247 	struct nfc_llcp_sdp_tlv *sdp;
248 	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
249 						    sdreq_timeout_work);
250 
251 	mutex_lock(&local->sdreq_lock);
252 
253 	time = jiffies - msecs_to_jiffies(3 * local->remote_lto);
254 
255 	hlist_for_each_entry_safe(sdp, n, &local->pending_sdreqs, node) {
256 		if (time_after(sdp->time, time))
257 			continue;
258 
259 		sdp->sap = LLCP_SDP_UNBOUND;
260 
261 		hlist_del(&sdp->node);
262 
263 		hlist_add_head(&sdp->node, &nl_sdres_list);
264 	}
265 
266 	if (!hlist_empty(&local->pending_sdreqs))
267 		mod_timer(&local->sdreq_timer,
268 			  jiffies + msecs_to_jiffies(3 * local->remote_lto));
269 
270 	mutex_unlock(&local->sdreq_lock);
271 
272 	if (!hlist_empty(&nl_sdres_list))
273 		nfc_genl_llc_send_sdres(local->dev, &nl_sdres_list);
274 }
275 
276 static void nfc_llcp_sdreq_timer(struct timer_list *t)
277 {
278 	struct nfc_llcp_local *local = from_timer(local, t, sdreq_timer);
279 
280 	schedule_work(&local->sdreq_timeout_work);
281 }
282 
283 struct nfc_llcp_local *nfc_llcp_find_local(struct nfc_dev *dev)
284 {
285 	struct nfc_llcp_local *local;
286 
287 	list_for_each_entry(local, &llcp_devices, list)
288 		if (local->dev == dev)
289 			return local;
290 
291 	pr_debug("No device found\n");
292 
293 	return NULL;
294 }
295 
296 static char *wks[] = {
297 	NULL,
298 	NULL, /* SDP */
299 	"urn:nfc:sn:ip",
300 	"urn:nfc:sn:obex",
301 	"urn:nfc:sn:snep",
302 };
303 
304 static int nfc_llcp_wks_sap(char *service_name, size_t service_name_len)
305 {
306 	int sap, num_wks;
307 
308 	pr_debug("%s\n", service_name);
309 
310 	if (service_name == NULL)
311 		return -EINVAL;
312 
313 	num_wks = ARRAY_SIZE(wks);
314 
315 	for (sap = 0; sap < num_wks; sap++) {
316 		if (wks[sap] == NULL)
317 			continue;
318 
319 		if (strncmp(wks[sap], service_name, service_name_len) == 0)
320 			return sap;
321 	}
322 
323 	return -EINVAL;
324 }
325 
326 static
327 struct nfc_llcp_sock *nfc_llcp_sock_from_sn(struct nfc_llcp_local *local,
328 					    u8 *sn, size_t sn_len)
329 {
330 	struct sock *sk;
331 	struct nfc_llcp_sock *llcp_sock, *tmp_sock;
332 
333 	pr_debug("sn %zd %p\n", sn_len, sn);
334 
335 	if (sn == NULL || sn_len == 0)
336 		return NULL;
337 
338 	read_lock(&local->sockets.lock);
339 
340 	llcp_sock = NULL;
341 
342 	sk_for_each(sk, &local->sockets.head) {
343 		tmp_sock = nfc_llcp_sock(sk);
344 
345 		pr_debug("llcp sock %p\n", tmp_sock);
346 
347 		if (tmp_sock->sk.sk_type == SOCK_STREAM &&
348 		    tmp_sock->sk.sk_state != LLCP_LISTEN)
349 			continue;
350 
351 		if (tmp_sock->sk.sk_type == SOCK_DGRAM &&
352 		    tmp_sock->sk.sk_state != LLCP_BOUND)
353 			continue;
354 
355 		if (tmp_sock->service_name == NULL ||
356 		    tmp_sock->service_name_len == 0)
357 			continue;
358 
359 		if (tmp_sock->service_name_len != sn_len)
360 			continue;
361 
362 		if (memcmp(sn, tmp_sock->service_name, sn_len) == 0) {
363 			llcp_sock = tmp_sock;
364 			break;
365 		}
366 	}
367 
368 	read_unlock(&local->sockets.lock);
369 
370 	pr_debug("Found llcp sock %p\n", llcp_sock);
371 
372 	return llcp_sock;
373 }
374 
375 u8 nfc_llcp_get_sdp_ssap(struct nfc_llcp_local *local,
376 			 struct nfc_llcp_sock *sock)
377 {
378 	mutex_lock(&local->sdp_lock);
379 
380 	if (sock->service_name != NULL && sock->service_name_len > 0) {
381 		int ssap = nfc_llcp_wks_sap(sock->service_name,
382 					    sock->service_name_len);
383 
384 		if (ssap > 0) {
385 			pr_debug("WKS %d\n", ssap);
386 
387 			/* This is a WKS, let's check if it's free */
388 			if (local->local_wks & BIT(ssap)) {
389 				mutex_unlock(&local->sdp_lock);
390 
391 				return LLCP_SAP_MAX;
392 			}
393 
394 			set_bit(ssap, &local->local_wks);
395 			mutex_unlock(&local->sdp_lock);
396 
397 			return ssap;
398 		}
399 
400 		/*
401 		 * Check if there already is a non WKS socket bound
402 		 * to this service name.
403 		 */
404 		if (nfc_llcp_sock_from_sn(local, sock->service_name,
405 					  sock->service_name_len) != NULL) {
406 			mutex_unlock(&local->sdp_lock);
407 
408 			return LLCP_SAP_MAX;
409 		}
410 
411 		mutex_unlock(&local->sdp_lock);
412 
413 		return LLCP_SDP_UNBOUND;
414 
415 	} else if (sock->ssap != 0 && sock->ssap < LLCP_WKS_NUM_SAP) {
416 		if (!test_bit(sock->ssap, &local->local_wks)) {
417 			set_bit(sock->ssap, &local->local_wks);
418 			mutex_unlock(&local->sdp_lock);
419 
420 			return sock->ssap;
421 		}
422 	}
423 
424 	mutex_unlock(&local->sdp_lock);
425 
426 	return LLCP_SAP_MAX;
427 }
428 
429 u8 nfc_llcp_get_local_ssap(struct nfc_llcp_local *local)
430 {
431 	u8 local_ssap;
432 
433 	mutex_lock(&local->sdp_lock);
434 
435 	local_ssap = find_first_zero_bit(&local->local_sap, LLCP_LOCAL_NUM_SAP);
436 	if (local_ssap == LLCP_LOCAL_NUM_SAP) {
437 		mutex_unlock(&local->sdp_lock);
438 		return LLCP_SAP_MAX;
439 	}
440 
441 	set_bit(local_ssap, &local->local_sap);
442 
443 	mutex_unlock(&local->sdp_lock);
444 
445 	return local_ssap + LLCP_LOCAL_SAP_OFFSET;
446 }
447 
448 void nfc_llcp_put_ssap(struct nfc_llcp_local *local, u8 ssap)
449 {
450 	u8 local_ssap;
451 	unsigned long *sdp;
452 
453 	if (ssap < LLCP_WKS_NUM_SAP) {
454 		local_ssap = ssap;
455 		sdp = &local->local_wks;
456 	} else if (ssap < LLCP_LOCAL_NUM_SAP) {
457 		atomic_t *client_cnt;
458 
459 		local_ssap = ssap - LLCP_WKS_NUM_SAP;
460 		sdp = &local->local_sdp;
461 		client_cnt = &local->local_sdp_cnt[local_ssap];
462 
463 		pr_debug("%d clients\n", atomic_read(client_cnt));
464 
465 		mutex_lock(&local->sdp_lock);
466 
467 		if (atomic_dec_and_test(client_cnt)) {
468 			struct nfc_llcp_sock *l_sock;
469 
470 			pr_debug("No more clients for SAP %d\n", ssap);
471 
472 			clear_bit(local_ssap, sdp);
473 
474 			/* Find the listening sock and set it back to UNBOUND */
475 			l_sock = nfc_llcp_sock_get(local, ssap, LLCP_SAP_SDP);
476 			if (l_sock) {
477 				l_sock->ssap = LLCP_SDP_UNBOUND;
478 				nfc_llcp_sock_put(l_sock);
479 			}
480 		}
481 
482 		mutex_unlock(&local->sdp_lock);
483 
484 		return;
485 	} else if (ssap < LLCP_MAX_SAP) {
486 		local_ssap = ssap - LLCP_LOCAL_NUM_SAP;
487 		sdp = &local->local_sap;
488 	} else {
489 		return;
490 	}
491 
492 	mutex_lock(&local->sdp_lock);
493 
494 	clear_bit(local_ssap, sdp);
495 
496 	mutex_unlock(&local->sdp_lock);
497 }
498 
499 static u8 nfc_llcp_reserve_sdp_ssap(struct nfc_llcp_local *local)
500 {
501 	u8 ssap;
502 
503 	mutex_lock(&local->sdp_lock);
504 
505 	ssap = find_first_zero_bit(&local->local_sdp, LLCP_SDP_NUM_SAP);
506 	if (ssap == LLCP_SDP_NUM_SAP) {
507 		mutex_unlock(&local->sdp_lock);
508 
509 		return LLCP_SAP_MAX;
510 	}
511 
512 	pr_debug("SDP ssap %d\n", LLCP_WKS_NUM_SAP + ssap);
513 
514 	set_bit(ssap, &local->local_sdp);
515 
516 	mutex_unlock(&local->sdp_lock);
517 
518 	return LLCP_WKS_NUM_SAP + ssap;
519 }
520 
521 static int nfc_llcp_build_gb(struct nfc_llcp_local *local)
522 {
523 	u8 *gb_cur, version, version_length;
524 	u8 lto_length, wks_length, miux_length;
525 	u8 *version_tlv = NULL, *lto_tlv = NULL,
526 	   *wks_tlv = NULL, *miux_tlv = NULL;
527 	__be16 wks = cpu_to_be16(local->local_wks);
528 	u8 gb_len = 0;
529 	int ret = 0;
530 
531 	version = LLCP_VERSION_11;
532 	version_tlv = nfc_llcp_build_tlv(LLCP_TLV_VERSION, &version,
533 					 1, &version_length);
534 	if (!version_tlv) {
535 		ret = -ENOMEM;
536 		goto out;
537 	}
538 	gb_len += version_length;
539 
540 	lto_tlv = nfc_llcp_build_tlv(LLCP_TLV_LTO, &local->lto, 1, &lto_length);
541 	if (!lto_tlv) {
542 		ret = -ENOMEM;
543 		goto out;
544 	}
545 	gb_len += lto_length;
546 
547 	pr_debug("Local wks 0x%lx\n", local->local_wks);
548 	wks_tlv = nfc_llcp_build_tlv(LLCP_TLV_WKS, (u8 *)&wks, 2, &wks_length);
549 	if (!wks_tlv) {
550 		ret = -ENOMEM;
551 		goto out;
552 	}
553 	gb_len += wks_length;
554 
555 	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&local->miux, 0,
556 				      &miux_length);
557 	if (!miux_tlv) {
558 		ret = -ENOMEM;
559 		goto out;
560 	}
561 	gb_len += miux_length;
562 
563 	gb_len += ARRAY_SIZE(llcp_magic);
564 
565 	if (gb_len > NFC_MAX_GT_LEN) {
566 		ret = -EINVAL;
567 		goto out;
568 	}
569 
570 	gb_cur = local->gb;
571 
572 	memcpy(gb_cur, llcp_magic, ARRAY_SIZE(llcp_magic));
573 	gb_cur += ARRAY_SIZE(llcp_magic);
574 
575 	memcpy(gb_cur, version_tlv, version_length);
576 	gb_cur += version_length;
577 
578 	memcpy(gb_cur, lto_tlv, lto_length);
579 	gb_cur += lto_length;
580 
581 	memcpy(gb_cur, wks_tlv, wks_length);
582 	gb_cur += wks_length;
583 
584 	memcpy(gb_cur, miux_tlv, miux_length);
585 	gb_cur += miux_length;
586 
587 	local->gb_len = gb_len;
588 
589 out:
590 	kfree(version_tlv);
591 	kfree(lto_tlv);
592 	kfree(wks_tlv);
593 	kfree(miux_tlv);
594 
595 	return ret;
596 }
597 
598 u8 *nfc_llcp_general_bytes(struct nfc_dev *dev, size_t *general_bytes_len)
599 {
600 	struct nfc_llcp_local *local;
601 
602 	local = nfc_llcp_find_local(dev);
603 	if (local == NULL) {
604 		*general_bytes_len = 0;
605 		return NULL;
606 	}
607 
608 	nfc_llcp_build_gb(local);
609 
610 	*general_bytes_len = local->gb_len;
611 
612 	return local->gb;
613 }
614 
615 int nfc_llcp_set_remote_gb(struct nfc_dev *dev, u8 *gb, u8 gb_len)
616 {
617 	struct nfc_llcp_local *local;
618 
619 	if (gb_len < 3 || gb_len > NFC_MAX_GT_LEN)
620 		return -EINVAL;
621 
622 	local = nfc_llcp_find_local(dev);
623 	if (local == NULL) {
624 		pr_err("No LLCP device\n");
625 		return -ENODEV;
626 	}
627 
628 	memset(local->remote_gb, 0, NFC_MAX_GT_LEN);
629 	memcpy(local->remote_gb, gb, gb_len);
630 	local->remote_gb_len = gb_len;
631 
632 	if (memcmp(local->remote_gb, llcp_magic, 3)) {
633 		pr_err("MAC does not support LLCP\n");
634 		return -EINVAL;
635 	}
636 
637 	return nfc_llcp_parse_gb_tlv(local,
638 				     &local->remote_gb[3],
639 				     local->remote_gb_len - 3);
640 }
641 
642 static u8 nfc_llcp_dsap(struct sk_buff *pdu)
643 {
644 	return (pdu->data[0] & 0xfc) >> 2;
645 }
646 
647 static u8 nfc_llcp_ptype(struct sk_buff *pdu)
648 {
649 	return ((pdu->data[0] & 0x03) << 2) | ((pdu->data[1] & 0xc0) >> 6);
650 }
651 
652 static u8 nfc_llcp_ssap(struct sk_buff *pdu)
653 {
654 	return pdu->data[1] & 0x3f;
655 }
656 
657 static u8 nfc_llcp_ns(struct sk_buff *pdu)
658 {
659 	return pdu->data[2] >> 4;
660 }
661 
662 static u8 nfc_llcp_nr(struct sk_buff *pdu)
663 {
664 	return pdu->data[2] & 0xf;
665 }
666 
667 static void nfc_llcp_set_nrns(struct nfc_llcp_sock *sock, struct sk_buff *pdu)
668 {
669 	pdu->data[2] = (sock->send_n << 4) | (sock->recv_n);
670 	sock->send_n = (sock->send_n + 1) % 16;
671 	sock->recv_ack_n = (sock->recv_n - 1) % 16;
672 }
673 
674 void nfc_llcp_send_to_raw_sock(struct nfc_llcp_local *local,
675 			       struct sk_buff *skb, u8 direction)
676 {
677 	struct sk_buff *skb_copy = NULL, *nskb;
678 	struct sock *sk;
679 	u8 *data;
680 
681 	read_lock(&local->raw_sockets.lock);
682 
683 	sk_for_each(sk, &local->raw_sockets.head) {
684 		if (sk->sk_state != LLCP_BOUND)
685 			continue;
686 
687 		if (skb_copy == NULL) {
688 			skb_copy = __pskb_copy_fclone(skb, NFC_RAW_HEADER_SIZE,
689 						      GFP_ATOMIC, true);
690 
691 			if (skb_copy == NULL)
692 				continue;
693 
694 			data = skb_push(skb_copy, NFC_RAW_HEADER_SIZE);
695 
696 			data[0] = local->dev ? local->dev->idx : 0xFF;
697 			data[1] = direction & 0x01;
698 			data[1] |= (RAW_PAYLOAD_LLCP << 1);
699 		}
700 
701 		nskb = skb_clone(skb_copy, GFP_ATOMIC);
702 		if (!nskb)
703 			continue;
704 
705 		if (sock_queue_rcv_skb(sk, nskb))
706 			kfree_skb(nskb);
707 	}
708 
709 	read_unlock(&local->raw_sockets.lock);
710 
711 	kfree_skb(skb_copy);
712 }
713 
714 static void nfc_llcp_tx_work(struct work_struct *work)
715 {
716 	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
717 						    tx_work);
718 	struct sk_buff *skb;
719 	struct sock *sk;
720 	struct nfc_llcp_sock *llcp_sock;
721 
722 	skb = skb_dequeue(&local->tx_queue);
723 	if (skb != NULL) {
724 		sk = skb->sk;
725 		llcp_sock = nfc_llcp_sock(sk);
726 
727 		if (llcp_sock == NULL && nfc_llcp_ptype(skb) == LLCP_PDU_I) {
728 			kfree_skb(skb);
729 			nfc_llcp_send_symm(local->dev);
730 		} else if (llcp_sock && !llcp_sock->remote_ready) {
731 			skb_queue_head(&local->tx_queue, skb);
732 			nfc_llcp_send_symm(local->dev);
733 		} else {
734 			struct sk_buff *copy_skb = NULL;
735 			u8 ptype = nfc_llcp_ptype(skb);
736 			int ret;
737 
738 			pr_debug("Sending pending skb\n");
739 			print_hex_dump_debug("LLCP Tx: ", DUMP_PREFIX_OFFSET,
740 					     16, 1, skb->data, skb->len, true);
741 
742 			if (ptype == LLCP_PDU_DISC && sk != NULL &&
743 			    sk->sk_state == LLCP_DISCONNECTING) {
744 				nfc_llcp_sock_unlink(&local->sockets, sk);
745 				sock_orphan(sk);
746 				sock_put(sk);
747 			}
748 
749 			if (ptype == LLCP_PDU_I)
750 				copy_skb = skb_copy(skb, GFP_ATOMIC);
751 
752 			__net_timestamp(skb);
753 
754 			nfc_llcp_send_to_raw_sock(local, skb,
755 						  NFC_DIRECTION_TX);
756 
757 			ret = nfc_data_exchange(local->dev, local->target_idx,
758 						skb, nfc_llcp_recv, local);
759 
760 			if (ret) {
761 				kfree_skb(copy_skb);
762 				goto out;
763 			}
764 
765 			if (ptype == LLCP_PDU_I && copy_skb)
766 				skb_queue_tail(&llcp_sock->tx_pending_queue,
767 					       copy_skb);
768 		}
769 	} else {
770 		nfc_llcp_send_symm(local->dev);
771 	}
772 
773 out:
774 	mod_timer(&local->link_timer,
775 		  jiffies + msecs_to_jiffies(2 * local->remote_lto));
776 }
777 
778 static struct nfc_llcp_sock *nfc_llcp_connecting_sock_get(struct nfc_llcp_local *local,
779 							  u8 ssap)
780 {
781 	struct sock *sk;
782 	struct nfc_llcp_sock *llcp_sock;
783 
784 	read_lock(&local->connecting_sockets.lock);
785 
786 	sk_for_each(sk, &local->connecting_sockets.head) {
787 		llcp_sock = nfc_llcp_sock(sk);
788 
789 		if (llcp_sock->ssap == ssap) {
790 			sock_hold(&llcp_sock->sk);
791 			goto out;
792 		}
793 	}
794 
795 	llcp_sock = NULL;
796 
797 out:
798 	read_unlock(&local->connecting_sockets.lock);
799 
800 	return llcp_sock;
801 }
802 
803 static struct nfc_llcp_sock *nfc_llcp_sock_get_sn(struct nfc_llcp_local *local,
804 						  u8 *sn, size_t sn_len)
805 {
806 	struct nfc_llcp_sock *llcp_sock;
807 
808 	llcp_sock = nfc_llcp_sock_from_sn(local, sn, sn_len);
809 
810 	if (llcp_sock == NULL)
811 		return NULL;
812 
813 	sock_hold(&llcp_sock->sk);
814 
815 	return llcp_sock;
816 }
817 
818 static u8 *nfc_llcp_connect_sn(struct sk_buff *skb, size_t *sn_len)
819 {
820 	u8 *tlv = &skb->data[2], type, length;
821 	size_t tlv_array_len = skb->len - LLCP_HEADER_SIZE, offset = 0;
822 
823 	while (offset < tlv_array_len) {
824 		type = tlv[0];
825 		length = tlv[1];
826 
827 		pr_debug("type 0x%x length %d\n", type, length);
828 
829 		if (type == LLCP_TLV_SN) {
830 			*sn_len = length;
831 			return &tlv[2];
832 		}
833 
834 		offset += length + 2;
835 		tlv += length + 2;
836 	}
837 
838 	return NULL;
839 }
840 
841 static void nfc_llcp_recv_ui(struct nfc_llcp_local *local,
842 			     struct sk_buff *skb)
843 {
844 	struct nfc_llcp_sock *llcp_sock;
845 	struct nfc_llcp_ui_cb *ui_cb;
846 	u8 dsap, ssap;
847 
848 	dsap = nfc_llcp_dsap(skb);
849 	ssap = nfc_llcp_ssap(skb);
850 
851 	ui_cb = nfc_llcp_ui_skb_cb(skb);
852 	ui_cb->dsap = dsap;
853 	ui_cb->ssap = ssap;
854 
855 	pr_debug("%d %d\n", dsap, ssap);
856 
857 	/* We're looking for a bound socket, not a client one */
858 	llcp_sock = nfc_llcp_sock_get(local, dsap, LLCP_SAP_SDP);
859 	if (llcp_sock == NULL || llcp_sock->sk.sk_type != SOCK_DGRAM)
860 		return;
861 
862 	/* There is no sequence with UI frames */
863 	skb_pull(skb, LLCP_HEADER_SIZE);
864 	if (!sock_queue_rcv_skb(&llcp_sock->sk, skb)) {
865 		/*
866 		 * UI frames will be freed from the socket layer, so we
867 		 * need to keep them alive until someone receives them.
868 		 */
869 		skb_get(skb);
870 	} else {
871 		pr_err("Receive queue is full\n");
872 	}
873 
874 	nfc_llcp_sock_put(llcp_sock);
875 }
876 
877 static void nfc_llcp_recv_connect(struct nfc_llcp_local *local,
878 				  struct sk_buff *skb)
879 {
880 	struct sock *new_sk, *parent;
881 	struct nfc_llcp_sock *sock, *new_sock;
882 	u8 dsap, ssap, reason;
883 
884 	dsap = nfc_llcp_dsap(skb);
885 	ssap = nfc_llcp_ssap(skb);
886 
887 	pr_debug("%d %d\n", dsap, ssap);
888 
889 	if (dsap != LLCP_SAP_SDP) {
890 		sock = nfc_llcp_sock_get(local, dsap, LLCP_SAP_SDP);
891 		if (sock == NULL || sock->sk.sk_state != LLCP_LISTEN) {
892 			reason = LLCP_DM_NOBOUND;
893 			goto fail;
894 		}
895 	} else {
896 		u8 *sn;
897 		size_t sn_len;
898 
899 		sn = nfc_llcp_connect_sn(skb, &sn_len);
900 		if (sn == NULL) {
901 			reason = LLCP_DM_NOBOUND;
902 			goto fail;
903 		}
904 
905 		pr_debug("Service name length %zu\n", sn_len);
906 
907 		sock = nfc_llcp_sock_get_sn(local, sn, sn_len);
908 		if (sock == NULL) {
909 			reason = LLCP_DM_NOBOUND;
910 			goto fail;
911 		}
912 	}
913 
914 	lock_sock(&sock->sk);
915 
916 	parent = &sock->sk;
917 
918 	if (sk_acceptq_is_full(parent)) {
919 		reason = LLCP_DM_REJ;
920 		release_sock(&sock->sk);
921 		sock_put(&sock->sk);
922 		goto fail;
923 	}
924 
925 	if (sock->ssap == LLCP_SDP_UNBOUND) {
926 		u8 ssap = nfc_llcp_reserve_sdp_ssap(local);
927 
928 		pr_debug("First client, reserving %d\n", ssap);
929 
930 		if (ssap == LLCP_SAP_MAX) {
931 			reason = LLCP_DM_REJ;
932 			release_sock(&sock->sk);
933 			sock_put(&sock->sk);
934 			goto fail;
935 		}
936 
937 		sock->ssap = ssap;
938 	}
939 
940 	new_sk = nfc_llcp_sock_alloc(NULL, parent->sk_type, GFP_ATOMIC, 0);
941 	if (new_sk == NULL) {
942 		reason = LLCP_DM_REJ;
943 		release_sock(&sock->sk);
944 		sock_put(&sock->sk);
945 		goto fail;
946 	}
947 
948 	new_sock = nfc_llcp_sock(new_sk);
949 	new_sock->dev = local->dev;
950 	new_sock->local = nfc_llcp_local_get(local);
951 	new_sock->rw = sock->rw;
952 	new_sock->miux = sock->miux;
953 	new_sock->nfc_protocol = sock->nfc_protocol;
954 	new_sock->dsap = ssap;
955 	new_sock->target_idx = local->target_idx;
956 	new_sock->parent = parent;
957 	new_sock->ssap = sock->ssap;
958 	if (sock->ssap < LLCP_LOCAL_NUM_SAP && sock->ssap >= LLCP_WKS_NUM_SAP) {
959 		atomic_t *client_count;
960 
961 		pr_debug("reserved_ssap %d for %p\n", sock->ssap, new_sock);
962 
963 		client_count =
964 			&local->local_sdp_cnt[sock->ssap - LLCP_WKS_NUM_SAP];
965 
966 		atomic_inc(client_count);
967 		new_sock->reserved_ssap = sock->ssap;
968 	}
969 
970 	nfc_llcp_parse_connection_tlv(new_sock, &skb->data[LLCP_HEADER_SIZE],
971 				      skb->len - LLCP_HEADER_SIZE);
972 
973 	pr_debug("new sock %p sk %p\n", new_sock, &new_sock->sk);
974 
975 	nfc_llcp_sock_link(&local->sockets, new_sk);
976 
977 	nfc_llcp_accept_enqueue(&sock->sk, new_sk);
978 
979 	nfc_get_device(local->dev->idx);
980 
981 	new_sk->sk_state = LLCP_CONNECTED;
982 
983 	/* Wake the listening processes */
984 	parent->sk_data_ready(parent);
985 
986 	/* Send CC */
987 	nfc_llcp_send_cc(new_sock);
988 
989 	release_sock(&sock->sk);
990 	sock_put(&sock->sk);
991 
992 	return;
993 
994 fail:
995 	/* Send DM */
996 	nfc_llcp_send_dm(local, dsap, ssap, reason);
997 }
998 
999 int nfc_llcp_queue_i_frames(struct nfc_llcp_sock *sock)
1000 {
1001 	int nr_frames = 0;
1002 	struct nfc_llcp_local *local = sock->local;
1003 
1004 	pr_debug("Remote ready %d tx queue len %d remote rw %d",
1005 		 sock->remote_ready, skb_queue_len(&sock->tx_pending_queue),
1006 		 sock->remote_rw);
1007 
1008 	/* Try to queue some I frames for transmission */
1009 	while (sock->remote_ready &&
1010 	       skb_queue_len(&sock->tx_pending_queue) < sock->remote_rw) {
1011 		struct sk_buff *pdu;
1012 
1013 		pdu = skb_dequeue(&sock->tx_queue);
1014 		if (pdu == NULL)
1015 			break;
1016 
1017 		/* Update N(S)/N(R) */
1018 		nfc_llcp_set_nrns(sock, pdu);
1019 
1020 		skb_queue_tail(&local->tx_queue, pdu);
1021 		nr_frames++;
1022 	}
1023 
1024 	return nr_frames;
1025 }
1026 
1027 static void nfc_llcp_recv_hdlc(struct nfc_llcp_local *local,
1028 			       struct sk_buff *skb)
1029 {
1030 	struct nfc_llcp_sock *llcp_sock;
1031 	struct sock *sk;
1032 	u8 dsap, ssap, ptype, ns, nr;
1033 
1034 	ptype = nfc_llcp_ptype(skb);
1035 	dsap = nfc_llcp_dsap(skb);
1036 	ssap = nfc_llcp_ssap(skb);
1037 	ns = nfc_llcp_ns(skb);
1038 	nr = nfc_llcp_nr(skb);
1039 
1040 	pr_debug("%d %d R %d S %d\n", dsap, ssap, nr, ns);
1041 
1042 	llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
1043 	if (llcp_sock == NULL) {
1044 		nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);
1045 		return;
1046 	}
1047 
1048 	sk = &llcp_sock->sk;
1049 	lock_sock(sk);
1050 	if (sk->sk_state == LLCP_CLOSED) {
1051 		release_sock(sk);
1052 		nfc_llcp_sock_put(llcp_sock);
1053 	}
1054 
1055 	/* Pass the payload upstream */
1056 	if (ptype == LLCP_PDU_I) {
1057 		pr_debug("I frame, queueing on %p\n", &llcp_sock->sk);
1058 
1059 		if (ns == llcp_sock->recv_n)
1060 			llcp_sock->recv_n = (llcp_sock->recv_n + 1) % 16;
1061 		else
1062 			pr_err("Received out of sequence I PDU\n");
1063 
1064 		skb_pull(skb, LLCP_HEADER_SIZE + LLCP_SEQUENCE_SIZE);
1065 		if (!sock_queue_rcv_skb(&llcp_sock->sk, skb)) {
1066 			/*
1067 			 * I frames will be freed from the socket layer, so we
1068 			 * need to keep them alive until someone receives them.
1069 			 */
1070 			skb_get(skb);
1071 		} else {
1072 			pr_err("Receive queue is full\n");
1073 		}
1074 	}
1075 
1076 	/* Remove skbs from the pending queue */
1077 	if (llcp_sock->send_ack_n != nr) {
1078 		struct sk_buff *s, *tmp;
1079 		u8 n;
1080 
1081 		llcp_sock->send_ack_n = nr;
1082 
1083 		/* Remove and free all skbs until ns == nr */
1084 		skb_queue_walk_safe(&llcp_sock->tx_pending_queue, s, tmp) {
1085 			n = nfc_llcp_ns(s);
1086 
1087 			skb_unlink(s, &llcp_sock->tx_pending_queue);
1088 			kfree_skb(s);
1089 
1090 			if (n == nr)
1091 				break;
1092 		}
1093 
1094 		/* Re-queue the remaining skbs for transmission */
1095 		skb_queue_reverse_walk_safe(&llcp_sock->tx_pending_queue,
1096 					    s, tmp) {
1097 			skb_unlink(s, &llcp_sock->tx_pending_queue);
1098 			skb_queue_head(&local->tx_queue, s);
1099 		}
1100 	}
1101 
1102 	if (ptype == LLCP_PDU_RR)
1103 		llcp_sock->remote_ready = true;
1104 	else if (ptype == LLCP_PDU_RNR)
1105 		llcp_sock->remote_ready = false;
1106 
1107 	if (nfc_llcp_queue_i_frames(llcp_sock) == 0 && ptype == LLCP_PDU_I)
1108 		nfc_llcp_send_rr(llcp_sock);
1109 
1110 	release_sock(sk);
1111 	nfc_llcp_sock_put(llcp_sock);
1112 }
1113 
1114 static void nfc_llcp_recv_disc(struct nfc_llcp_local *local,
1115 			       struct sk_buff *skb)
1116 {
1117 	struct nfc_llcp_sock *llcp_sock;
1118 	struct sock *sk;
1119 	u8 dsap, ssap;
1120 
1121 	dsap = nfc_llcp_dsap(skb);
1122 	ssap = nfc_llcp_ssap(skb);
1123 
1124 	if ((dsap == 0) && (ssap == 0)) {
1125 		pr_debug("Connection termination");
1126 		nfc_dep_link_down(local->dev);
1127 		return;
1128 	}
1129 
1130 	llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
1131 	if (llcp_sock == NULL) {
1132 		nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);
1133 		return;
1134 	}
1135 
1136 	sk = &llcp_sock->sk;
1137 	lock_sock(sk);
1138 
1139 	nfc_llcp_socket_purge(llcp_sock);
1140 
1141 	if (sk->sk_state == LLCP_CLOSED) {
1142 		release_sock(sk);
1143 		nfc_llcp_sock_put(llcp_sock);
1144 	}
1145 
1146 	if (sk->sk_state == LLCP_CONNECTED) {
1147 		nfc_put_device(local->dev);
1148 		sk->sk_state = LLCP_CLOSED;
1149 		sk->sk_state_change(sk);
1150 	}
1151 
1152 	nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_DISC);
1153 
1154 	release_sock(sk);
1155 	nfc_llcp_sock_put(llcp_sock);
1156 }
1157 
1158 static void nfc_llcp_recv_cc(struct nfc_llcp_local *local, struct sk_buff *skb)
1159 {
1160 	struct nfc_llcp_sock *llcp_sock;
1161 	struct sock *sk;
1162 	u8 dsap, ssap;
1163 
1164 	dsap = nfc_llcp_dsap(skb);
1165 	ssap = nfc_llcp_ssap(skb);
1166 
1167 	llcp_sock = nfc_llcp_connecting_sock_get(local, dsap);
1168 	if (llcp_sock == NULL) {
1169 		pr_err("Invalid CC\n");
1170 		nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);
1171 
1172 		return;
1173 	}
1174 
1175 	sk = &llcp_sock->sk;
1176 
1177 	/* Unlink from connecting and link to the client array */
1178 	nfc_llcp_sock_unlink(&local->connecting_sockets, sk);
1179 	nfc_llcp_sock_link(&local->sockets, sk);
1180 	llcp_sock->dsap = ssap;
1181 
1182 	nfc_llcp_parse_connection_tlv(llcp_sock, &skb->data[LLCP_HEADER_SIZE],
1183 				      skb->len - LLCP_HEADER_SIZE);
1184 
1185 	sk->sk_state = LLCP_CONNECTED;
1186 	sk->sk_state_change(sk);
1187 
1188 	nfc_llcp_sock_put(llcp_sock);
1189 }
1190 
1191 static void nfc_llcp_recv_dm(struct nfc_llcp_local *local, struct sk_buff *skb)
1192 {
1193 	struct nfc_llcp_sock *llcp_sock;
1194 	struct sock *sk;
1195 	u8 dsap, ssap, reason;
1196 
1197 	dsap = nfc_llcp_dsap(skb);
1198 	ssap = nfc_llcp_ssap(skb);
1199 	reason = skb->data[2];
1200 
1201 	pr_debug("%d %d reason %d\n", ssap, dsap, reason);
1202 
1203 	switch (reason) {
1204 	case LLCP_DM_NOBOUND:
1205 	case LLCP_DM_REJ:
1206 		llcp_sock = nfc_llcp_connecting_sock_get(local, dsap);
1207 		break;
1208 
1209 	default:
1210 		llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
1211 		break;
1212 	}
1213 
1214 	if (llcp_sock == NULL) {
1215 		pr_debug("Already closed\n");
1216 		return;
1217 	}
1218 
1219 	sk = &llcp_sock->sk;
1220 
1221 	sk->sk_err = ENXIO;
1222 	sk->sk_state = LLCP_CLOSED;
1223 	sk->sk_state_change(sk);
1224 
1225 	nfc_llcp_sock_put(llcp_sock);
1226 }
1227 
1228 static void nfc_llcp_recv_snl(struct nfc_llcp_local *local,
1229 			      struct sk_buff *skb)
1230 {
1231 	struct nfc_llcp_sock *llcp_sock;
1232 	u8 dsap, ssap, *tlv, type, length, tid, sap;
1233 	u16 tlv_len, offset;
1234 	char *service_name;
1235 	size_t service_name_len;
1236 	struct nfc_llcp_sdp_tlv *sdp;
1237 	HLIST_HEAD(llc_sdres_list);
1238 	size_t sdres_tlvs_len;
1239 	HLIST_HEAD(nl_sdres_list);
1240 
1241 	dsap = nfc_llcp_dsap(skb);
1242 	ssap = nfc_llcp_ssap(skb);
1243 
1244 	pr_debug("%d %d\n", dsap, ssap);
1245 
1246 	if (dsap != LLCP_SAP_SDP || ssap != LLCP_SAP_SDP) {
1247 		pr_err("Wrong SNL SAP\n");
1248 		return;
1249 	}
1250 
1251 	tlv = &skb->data[LLCP_HEADER_SIZE];
1252 	tlv_len = skb->len - LLCP_HEADER_SIZE;
1253 	offset = 0;
1254 	sdres_tlvs_len = 0;
1255 
1256 	while (offset < tlv_len) {
1257 		type = tlv[0];
1258 		length = tlv[1];
1259 
1260 		switch (type) {
1261 		case LLCP_TLV_SDREQ:
1262 			tid = tlv[2];
1263 			service_name = (char *) &tlv[3];
1264 			service_name_len = length - 1;
1265 
1266 			pr_debug("Looking for %.16s\n", service_name);
1267 
1268 			if (service_name_len == strlen("urn:nfc:sn:sdp") &&
1269 			    !strncmp(service_name, "urn:nfc:sn:sdp",
1270 				     service_name_len)) {
1271 				sap = 1;
1272 				goto add_snl;
1273 			}
1274 
1275 			llcp_sock = nfc_llcp_sock_from_sn(local, service_name,
1276 							  service_name_len);
1277 			if (!llcp_sock) {
1278 				sap = 0;
1279 				goto add_snl;
1280 			}
1281 
1282 			/*
1283 			 * We found a socket but its ssap has not been reserved
1284 			 * yet. We need to assign it for good and send a reply.
1285 			 * The ssap will be freed when the socket is closed.
1286 			 */
1287 			if (llcp_sock->ssap == LLCP_SDP_UNBOUND) {
1288 				atomic_t *client_count;
1289 
1290 				sap = nfc_llcp_reserve_sdp_ssap(local);
1291 
1292 				pr_debug("Reserving %d\n", sap);
1293 
1294 				if (sap == LLCP_SAP_MAX) {
1295 					sap = 0;
1296 					goto add_snl;
1297 				}
1298 
1299 				client_count =
1300 					&local->local_sdp_cnt[sap -
1301 							      LLCP_WKS_NUM_SAP];
1302 
1303 				atomic_inc(client_count);
1304 
1305 				llcp_sock->ssap = sap;
1306 				llcp_sock->reserved_ssap = sap;
1307 			} else {
1308 				sap = llcp_sock->ssap;
1309 			}
1310 
1311 			pr_debug("%p %d\n", llcp_sock, sap);
1312 
1313 add_snl:
1314 			sdp = nfc_llcp_build_sdres_tlv(tid, sap);
1315 			if (sdp == NULL)
1316 				goto exit;
1317 
1318 			sdres_tlvs_len += sdp->tlv_len;
1319 			hlist_add_head(&sdp->node, &llc_sdres_list);
1320 			break;
1321 
1322 		case LLCP_TLV_SDRES:
1323 			mutex_lock(&local->sdreq_lock);
1324 
1325 			pr_debug("LLCP_TLV_SDRES: searching tid %d\n", tlv[2]);
1326 
1327 			hlist_for_each_entry(sdp, &local->pending_sdreqs, node) {
1328 				if (sdp->tid != tlv[2])
1329 					continue;
1330 
1331 				sdp->sap = tlv[3];
1332 
1333 				pr_debug("Found: uri=%s, sap=%d\n",
1334 					 sdp->uri, sdp->sap);
1335 
1336 				hlist_del(&sdp->node);
1337 
1338 				hlist_add_head(&sdp->node, &nl_sdres_list);
1339 
1340 				break;
1341 			}
1342 
1343 			mutex_unlock(&local->sdreq_lock);
1344 			break;
1345 
1346 		default:
1347 			pr_err("Invalid SNL tlv value 0x%x\n", type);
1348 			break;
1349 		}
1350 
1351 		offset += length + 2;
1352 		tlv += length + 2;
1353 	}
1354 
1355 exit:
1356 	if (!hlist_empty(&nl_sdres_list))
1357 		nfc_genl_llc_send_sdres(local->dev, &nl_sdres_list);
1358 
1359 	if (!hlist_empty(&llc_sdres_list))
1360 		nfc_llcp_send_snl_sdres(local, &llc_sdres_list, sdres_tlvs_len);
1361 }
1362 
1363 static void nfc_llcp_recv_agf(struct nfc_llcp_local *local, struct sk_buff *skb)
1364 {
1365 	u8 ptype;
1366 	u16 pdu_len;
1367 	struct sk_buff *new_skb;
1368 
1369 	if (skb->len <= LLCP_HEADER_SIZE) {
1370 		pr_err("Malformed AGF PDU\n");
1371 		return;
1372 	}
1373 
1374 	skb_pull(skb, LLCP_HEADER_SIZE);
1375 
1376 	while (skb->len > LLCP_AGF_PDU_HEADER_SIZE) {
1377 		pdu_len = skb->data[0] << 8 | skb->data[1];
1378 
1379 		skb_pull(skb, LLCP_AGF_PDU_HEADER_SIZE);
1380 
1381 		if (pdu_len < LLCP_HEADER_SIZE || pdu_len > skb->len) {
1382 			pr_err("Malformed AGF PDU\n");
1383 			return;
1384 		}
1385 
1386 		ptype = nfc_llcp_ptype(skb);
1387 
1388 		if (ptype == LLCP_PDU_SYMM || ptype == LLCP_PDU_AGF)
1389 			goto next;
1390 
1391 		new_skb = nfc_alloc_recv_skb(pdu_len, GFP_KERNEL);
1392 		if (new_skb == NULL) {
1393 			pr_err("Could not allocate PDU\n");
1394 			return;
1395 		}
1396 
1397 		skb_put_data(new_skb, skb->data, pdu_len);
1398 
1399 		nfc_llcp_rx_skb(local, new_skb);
1400 
1401 		kfree_skb(new_skb);
1402 next:
1403 		skb_pull(skb, pdu_len);
1404 	}
1405 }
1406 
1407 static void nfc_llcp_rx_skb(struct nfc_llcp_local *local, struct sk_buff *skb)
1408 {
1409 	u8 dsap, ssap, ptype;
1410 
1411 	ptype = nfc_llcp_ptype(skb);
1412 	dsap = nfc_llcp_dsap(skb);
1413 	ssap = nfc_llcp_ssap(skb);
1414 
1415 	pr_debug("ptype 0x%x dsap 0x%x ssap 0x%x\n", ptype, dsap, ssap);
1416 
1417 	if (ptype != LLCP_PDU_SYMM)
1418 		print_hex_dump_debug("LLCP Rx: ", DUMP_PREFIX_OFFSET, 16, 1,
1419 				     skb->data, skb->len, true);
1420 
1421 	switch (ptype) {
1422 	case LLCP_PDU_SYMM:
1423 		pr_debug("SYMM\n");
1424 		break;
1425 
1426 	case LLCP_PDU_UI:
1427 		pr_debug("UI\n");
1428 		nfc_llcp_recv_ui(local, skb);
1429 		break;
1430 
1431 	case LLCP_PDU_CONNECT:
1432 		pr_debug("CONNECT\n");
1433 		nfc_llcp_recv_connect(local, skb);
1434 		break;
1435 
1436 	case LLCP_PDU_DISC:
1437 		pr_debug("DISC\n");
1438 		nfc_llcp_recv_disc(local, skb);
1439 		break;
1440 
1441 	case LLCP_PDU_CC:
1442 		pr_debug("CC\n");
1443 		nfc_llcp_recv_cc(local, skb);
1444 		break;
1445 
1446 	case LLCP_PDU_DM:
1447 		pr_debug("DM\n");
1448 		nfc_llcp_recv_dm(local, skb);
1449 		break;
1450 
1451 	case LLCP_PDU_SNL:
1452 		pr_debug("SNL\n");
1453 		nfc_llcp_recv_snl(local, skb);
1454 		break;
1455 
1456 	case LLCP_PDU_I:
1457 	case LLCP_PDU_RR:
1458 	case LLCP_PDU_RNR:
1459 		pr_debug("I frame\n");
1460 		nfc_llcp_recv_hdlc(local, skb);
1461 		break;
1462 
1463 	case LLCP_PDU_AGF:
1464 		pr_debug("AGF frame\n");
1465 		nfc_llcp_recv_agf(local, skb);
1466 		break;
1467 	}
1468 }
1469 
1470 static void nfc_llcp_rx_work(struct work_struct *work)
1471 {
1472 	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
1473 						    rx_work);
1474 	struct sk_buff *skb;
1475 
1476 	skb = local->rx_pending;
1477 	if (skb == NULL) {
1478 		pr_debug("No pending SKB\n");
1479 		return;
1480 	}
1481 
1482 	__net_timestamp(skb);
1483 
1484 	nfc_llcp_send_to_raw_sock(local, skb, NFC_DIRECTION_RX);
1485 
1486 	nfc_llcp_rx_skb(local, skb);
1487 
1488 	schedule_work(&local->tx_work);
1489 	kfree_skb(local->rx_pending);
1490 	local->rx_pending = NULL;
1491 }
1492 
1493 static void __nfc_llcp_recv(struct nfc_llcp_local *local, struct sk_buff *skb)
1494 {
1495 	local->rx_pending = skb;
1496 	del_timer(&local->link_timer);
1497 	schedule_work(&local->rx_work);
1498 }
1499 
1500 void nfc_llcp_recv(void *data, struct sk_buff *skb, int err)
1501 {
1502 	struct nfc_llcp_local *local = (struct nfc_llcp_local *) data;
1503 
1504 	pr_debug("Received an LLCP PDU\n");
1505 	if (err < 0) {
1506 		pr_err("err %d\n", err);
1507 		return;
1508 	}
1509 
1510 	__nfc_llcp_recv(local, skb);
1511 }
1512 
1513 int nfc_llcp_data_received(struct nfc_dev *dev, struct sk_buff *skb)
1514 {
1515 	struct nfc_llcp_local *local;
1516 
1517 	local = nfc_llcp_find_local(dev);
1518 	if (local == NULL) {
1519 		kfree_skb(skb);
1520 		return -ENODEV;
1521 	}
1522 
1523 	__nfc_llcp_recv(local, skb);
1524 
1525 	return 0;
1526 }
1527 
1528 void nfc_llcp_mac_is_down(struct nfc_dev *dev)
1529 {
1530 	struct nfc_llcp_local *local;
1531 
1532 	local = nfc_llcp_find_local(dev);
1533 	if (local == NULL)
1534 		return;
1535 
1536 	local->remote_miu = LLCP_DEFAULT_MIU;
1537 	local->remote_lto = LLCP_DEFAULT_LTO;
1538 
1539 	/* Close and purge all existing sockets */
1540 	nfc_llcp_socket_release(local, true, 0);
1541 }
1542 
1543 void nfc_llcp_mac_is_up(struct nfc_dev *dev, u32 target_idx,
1544 			u8 comm_mode, u8 rf_mode)
1545 {
1546 	struct nfc_llcp_local *local;
1547 
1548 	pr_debug("rf mode %d\n", rf_mode);
1549 
1550 	local = nfc_llcp_find_local(dev);
1551 	if (local == NULL)
1552 		return;
1553 
1554 	local->target_idx = target_idx;
1555 	local->comm_mode = comm_mode;
1556 	local->rf_mode = rf_mode;
1557 
1558 	if (rf_mode == NFC_RF_INITIATOR) {
1559 		pr_debug("Queueing Tx work\n");
1560 
1561 		schedule_work(&local->tx_work);
1562 	} else {
1563 		mod_timer(&local->link_timer,
1564 			  jiffies + msecs_to_jiffies(local->remote_lto));
1565 	}
1566 }
1567 
1568 int nfc_llcp_register_device(struct nfc_dev *ndev)
1569 {
1570 	struct nfc_llcp_local *local;
1571 
1572 	local = kzalloc(sizeof(struct nfc_llcp_local), GFP_KERNEL);
1573 	if (local == NULL)
1574 		return -ENOMEM;
1575 
1576 	local->dev = ndev;
1577 	INIT_LIST_HEAD(&local->list);
1578 	kref_init(&local->ref);
1579 	mutex_init(&local->sdp_lock);
1580 	timer_setup(&local->link_timer, nfc_llcp_symm_timer, 0);
1581 
1582 	skb_queue_head_init(&local->tx_queue);
1583 	INIT_WORK(&local->tx_work, nfc_llcp_tx_work);
1584 
1585 	local->rx_pending = NULL;
1586 	INIT_WORK(&local->rx_work, nfc_llcp_rx_work);
1587 
1588 	INIT_WORK(&local->timeout_work, nfc_llcp_timeout_work);
1589 
1590 	rwlock_init(&local->sockets.lock);
1591 	rwlock_init(&local->connecting_sockets.lock);
1592 	rwlock_init(&local->raw_sockets.lock);
1593 
1594 	local->lto = 150; /* 1500 ms */
1595 	local->rw = LLCP_MAX_RW;
1596 	local->miux = cpu_to_be16(LLCP_MAX_MIUX);
1597 	local->local_wks = 0x1; /* LLC Link Management */
1598 
1599 	nfc_llcp_build_gb(local);
1600 
1601 	local->remote_miu = LLCP_DEFAULT_MIU;
1602 	local->remote_lto = LLCP_DEFAULT_LTO;
1603 
1604 	mutex_init(&local->sdreq_lock);
1605 	INIT_HLIST_HEAD(&local->pending_sdreqs);
1606 	timer_setup(&local->sdreq_timer, nfc_llcp_sdreq_timer, 0);
1607 	INIT_WORK(&local->sdreq_timeout_work, nfc_llcp_sdreq_timeout_work);
1608 
1609 	list_add(&local->list, &llcp_devices);
1610 
1611 	return 0;
1612 }
1613 
1614 void nfc_llcp_unregister_device(struct nfc_dev *dev)
1615 {
1616 	struct nfc_llcp_local *local = nfc_llcp_find_local(dev);
1617 
1618 	if (local == NULL) {
1619 		pr_debug("No such device\n");
1620 		return;
1621 	}
1622 
1623 	local_cleanup(local);
1624 
1625 	nfc_llcp_local_put(local);
1626 }
1627 
1628 int __init nfc_llcp_init(void)
1629 {
1630 	return nfc_llcp_sock_init();
1631 }
1632 
1633 void nfc_llcp_exit(void)
1634 {
1635 	nfc_llcp_sock_exit();
1636 }
1637