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  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/module.h>
 23#include <linux/nfc.h>
 24
 25#include <net/nfc/nfc.h>
 26
 27#include "nfc.h"
 28#include "llcp.h"
 29
 30static u8 llcp_tlv_length[LLCP_TLV_MAX] = {
 31	0,
 32	1, /* VERSION */
 33	2, /* MIUX */
 34	2, /* WKS */
 35	1, /* LTO */
 36	1, /* RW */
 37	0, /* SN */
 38	1, /* OPT */
 39	0, /* SDREQ */
 40	2, /* SDRES */
 41
 42};
 43
 44static u8 llcp_tlv8(u8 *tlv, u8 type)
 45{
 46	if (tlv[0] != type || tlv[1] != llcp_tlv_length[tlv[0]])
 47		return 0;
 48
 49	return tlv[2];
 50}
 51
 52static u16 llcp_tlv16(u8 *tlv, u8 type)
 53{
 54	if (tlv[0] != type || tlv[1] != llcp_tlv_length[tlv[0]])
 55		return 0;
 56
 57	return be16_to_cpu(*((__be16 *)(tlv + 2)));
 58}
 59
 60
 61static u8 llcp_tlv_version(u8 *tlv)
 62{
 63	return llcp_tlv8(tlv, LLCP_TLV_VERSION);
 64}
 65
 66static u16 llcp_tlv_miux(u8 *tlv)
 67{
 68	return llcp_tlv16(tlv, LLCP_TLV_MIUX) & 0x7ff;
 69}
 70
 71static u16 llcp_tlv_wks(u8 *tlv)
 72{
 73	return llcp_tlv16(tlv, LLCP_TLV_WKS);
 74}
 75
 76static u16 llcp_tlv_lto(u8 *tlv)
 77{
 78	return llcp_tlv8(tlv, LLCP_TLV_LTO);
 79}
 80
 81static u8 llcp_tlv_opt(u8 *tlv)
 82{
 83	return llcp_tlv8(tlv, LLCP_TLV_OPT);
 84}
 85
 86static u8 llcp_tlv_rw(u8 *tlv)
 87{
 88	return llcp_tlv8(tlv, LLCP_TLV_RW) & 0xf;
 89}
 90
 91u8 *nfc_llcp_build_tlv(u8 type, u8 *value, u8 value_length, u8 *tlv_length)
 92{
 93	u8 *tlv, length;
 94
 95	pr_debug("type %d\n", type);
 96
 97	if (type >= LLCP_TLV_MAX)
 98		return NULL;
 99
100	length = llcp_tlv_length[type];
101	if (length == 0 && value_length == 0)
102		return NULL;
103	else if (length == 0)
104		length = value_length;
105
106	*tlv_length = 2 + length;
107	tlv = kzalloc(2 + length, GFP_KERNEL);
108	if (tlv == NULL)
109		return tlv;
110
111	tlv[0] = type;
112	tlv[1] = length;
113	memcpy(tlv + 2, value, length);
114
115	return tlv;
116}
117
118struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdres_tlv(u8 tid, u8 sap)
119{
120	struct nfc_llcp_sdp_tlv *sdres;
121	u8 value[2];
122
123	sdres = kzalloc(sizeof(struct nfc_llcp_sdp_tlv), GFP_KERNEL);
124	if (sdres == NULL)
125		return NULL;
126
127	value[0] = tid;
128	value[1] = sap;
129
130	sdres->tlv = nfc_llcp_build_tlv(LLCP_TLV_SDRES, value, 2,
131					&sdres->tlv_len);
132	if (sdres->tlv == NULL) {
133		kfree(sdres);
134		return NULL;
135	}
136
137	sdres->tid = tid;
138	sdres->sap = sap;
139
140	INIT_HLIST_NODE(&sdres->node);
141
142	return sdres;
143}
144
145struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdreq_tlv(u8 tid, char *uri,
146						  size_t uri_len)
147{
148	struct nfc_llcp_sdp_tlv *sdreq;
149
150	pr_debug("uri: %s, len: %zu\n", uri, uri_len);
151
152	sdreq = kzalloc(sizeof(struct nfc_llcp_sdp_tlv), GFP_KERNEL);
153	if (sdreq == NULL)
154		return NULL;
155
156	sdreq->tlv_len = uri_len + 3;
157
158	if (uri[uri_len - 1] == 0)
159		sdreq->tlv_len--;
160
161	sdreq->tlv = kzalloc(sdreq->tlv_len + 1, GFP_KERNEL);
162	if (sdreq->tlv == NULL) {
163		kfree(sdreq);
164		return NULL;
165	}
166
167	sdreq->tlv[0] = LLCP_TLV_SDREQ;
168	sdreq->tlv[1] = sdreq->tlv_len - 2;
169	sdreq->tlv[2] = tid;
170
171	sdreq->tid = tid;
172	sdreq->uri = sdreq->tlv + 3;
173	memcpy(sdreq->uri, uri, uri_len);
174
175	sdreq->time = jiffies;
176
177	INIT_HLIST_NODE(&sdreq->node);
178
179	return sdreq;
180}
181
182void nfc_llcp_free_sdp_tlv(struct nfc_llcp_sdp_tlv *sdp)
183{
184	kfree(sdp->tlv);
185	kfree(sdp);
186}
187
188void nfc_llcp_free_sdp_tlv_list(struct hlist_head *head)
189{
190	struct nfc_llcp_sdp_tlv *sdp;
191	struct hlist_node *n;
192
193	hlist_for_each_entry_safe(sdp, n, head, node) {
194		hlist_del(&sdp->node);
195
196		nfc_llcp_free_sdp_tlv(sdp);
197	}
198}
199
200int nfc_llcp_parse_gb_tlv(struct nfc_llcp_local *local,
201			  u8 *tlv_array, u16 tlv_array_len)
202{
203	u8 *tlv = tlv_array, type, length, offset = 0;
204
205	pr_debug("TLV array length %d\n", tlv_array_len);
206
207	if (local == NULL)
208		return -ENODEV;
209
210	while (offset < tlv_array_len) {
211		type = tlv[0];
212		length = tlv[1];
213
214		pr_debug("type 0x%x length %d\n", type, length);
215
216		switch (type) {
217		case LLCP_TLV_VERSION:
218			local->remote_version = llcp_tlv_version(tlv);
219			break;
220		case LLCP_TLV_MIUX:
221			local->remote_miu = llcp_tlv_miux(tlv) + 128;
222			break;
223		case LLCP_TLV_WKS:
224			local->remote_wks = llcp_tlv_wks(tlv);
225			break;
226		case LLCP_TLV_LTO:
227			local->remote_lto = llcp_tlv_lto(tlv) * 10;
228			break;
229		case LLCP_TLV_OPT:
230			local->remote_opt = llcp_tlv_opt(tlv);
231			break;
232		default:
233			pr_err("Invalid gt tlv value 0x%x\n", type);
234			break;
235		}
236
237		offset += length + 2;
238		tlv += length + 2;
239	}
240
241	pr_debug("version 0x%x miu %d lto %d opt 0x%x wks 0x%x\n",
242		 local->remote_version, local->remote_miu,
243		 local->remote_lto, local->remote_opt,
244		 local->remote_wks);
245
246	return 0;
247}
248
249int nfc_llcp_parse_connection_tlv(struct nfc_llcp_sock *sock,
250				  u8 *tlv_array, u16 tlv_array_len)
251{
252	u8 *tlv = tlv_array, type, length, offset = 0;
253
254	pr_debug("TLV array length %d\n", tlv_array_len);
255
256	if (sock == NULL)
257		return -ENOTCONN;
258
259	while (offset < tlv_array_len) {
260		type = tlv[0];
261		length = tlv[1];
262
263		pr_debug("type 0x%x length %d\n", type, length);
264
265		switch (type) {
266		case LLCP_TLV_MIUX:
267			sock->remote_miu = llcp_tlv_miux(tlv) + 128;
268			break;
269		case LLCP_TLV_RW:
270			sock->remote_rw = llcp_tlv_rw(tlv);
271			break;
272		case LLCP_TLV_SN:
273			break;
274		default:
275			pr_err("Invalid gt tlv value 0x%x\n", type);
276			break;
277		}
278
279		offset += length + 2;
280		tlv += length + 2;
281	}
282
283	pr_debug("sock %p rw %d miu %d\n", sock,
284		 sock->remote_rw, sock->remote_miu);
285
286	return 0;
287}
288
289static struct sk_buff *llcp_add_header(struct sk_buff *pdu,
290				       u8 dsap, u8 ssap, u8 ptype)
291{
292	u8 header[2];
293
294	pr_debug("ptype 0x%x dsap 0x%x ssap 0x%x\n", ptype, dsap, ssap);
295
296	header[0] = (u8)((dsap << 2) | (ptype >> 2));
297	header[1] = (u8)((ptype << 6) | ssap);
298
299	pr_debug("header 0x%x 0x%x\n", header[0], header[1]);
300
301	memcpy(skb_put(pdu, LLCP_HEADER_SIZE), header, LLCP_HEADER_SIZE);
302
303	return pdu;
304}
305
306static struct sk_buff *llcp_add_tlv(struct sk_buff *pdu, u8 *tlv,
307				    u8 tlv_length)
308{
309	/* XXX Add an skb length check */
310
311	if (tlv == NULL)
312		return NULL;
313
314	memcpy(skb_put(pdu, tlv_length), tlv, tlv_length);
315
316	return pdu;
317}
318
319static struct sk_buff *llcp_allocate_pdu(struct nfc_llcp_sock *sock,
320					 u8 cmd, u16 size)
321{
322	struct sk_buff *skb;
323	int err;
324
325	if (sock->ssap == 0)
326		return NULL;
327
328	skb = nfc_alloc_send_skb(sock->dev, &sock->sk, MSG_DONTWAIT,
329				 size + LLCP_HEADER_SIZE, &err);
330	if (skb == NULL) {
331		pr_err("Could not allocate PDU\n");
332		return NULL;
333	}
334
335	skb = llcp_add_header(skb, sock->dsap, sock->ssap, cmd);
336
337	return skb;
338}
339
340int nfc_llcp_send_disconnect(struct nfc_llcp_sock *sock)
341{
342	struct sk_buff *skb;
343	struct nfc_dev *dev;
344	struct nfc_llcp_local *local;
345
346	pr_debug("Sending DISC\n");
347
348	local = sock->local;
349	if (local == NULL)
350		return -ENODEV;
351
352	dev = sock->dev;
353	if (dev == NULL)
354		return -ENODEV;
355
356	skb = llcp_allocate_pdu(sock, LLCP_PDU_DISC, 0);
357	if (skb == NULL)
358		return -ENOMEM;
359
360	skb_queue_tail(&local->tx_queue, skb);
361
362	return 0;
363}
364
365int nfc_llcp_send_symm(struct nfc_dev *dev)
366{
367	struct sk_buff *skb;
368	struct nfc_llcp_local *local;
369	u16 size = 0;
370
371	pr_debug("Sending SYMM\n");
372
373	local = nfc_llcp_find_local(dev);
374	if (local == NULL)
375		return -ENODEV;
376
377	size += LLCP_HEADER_SIZE;
378	size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
379
380	skb = alloc_skb(size, GFP_KERNEL);
381	if (skb == NULL)
382		return -ENOMEM;
383
384	skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
385
386	skb = llcp_add_header(skb, 0, 0, LLCP_PDU_SYMM);
387
388	__net_timestamp(skb);
389
390	nfc_llcp_send_to_raw_sock(local, skb, NFC_DIRECTION_TX);
391
392	return nfc_data_exchange(dev, local->target_idx, skb,
393				 nfc_llcp_recv, local);
394}
395
396int nfc_llcp_send_connect(struct nfc_llcp_sock *sock)
397{
398	struct nfc_llcp_local *local;
399	struct sk_buff *skb;
400	u8 *service_name_tlv = NULL, service_name_tlv_length;
401	u8 *miux_tlv = NULL, miux_tlv_length;
402	u8 *rw_tlv = NULL, rw_tlv_length, rw;
403	int err;
404	u16 size = 0;
405	__be16 miux;
406
407	pr_debug("Sending CONNECT\n");
408
409	local = sock->local;
410	if (local == NULL)
411		return -ENODEV;
412
413	if (sock->service_name != NULL) {
414		service_name_tlv = nfc_llcp_build_tlv(LLCP_TLV_SN,
415						      sock->service_name,
416						      sock->service_name_len,
417						      &service_name_tlv_length);
418		size += service_name_tlv_length;
419	}
420
421	/* If the socket parameters are not set, use the local ones */
422	miux = be16_to_cpu(sock->miux) > LLCP_MAX_MIUX ?
423		local->miux : sock->miux;
424	rw = sock->rw > LLCP_MAX_RW ? local->rw : sock->rw;
425
426	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
427				      &miux_tlv_length);
428	size += miux_tlv_length;
429
430	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
431	size += rw_tlv_length;
432
433	pr_debug("SKB size %d SN length %zu\n", size, sock->service_name_len);
434
435	skb = llcp_allocate_pdu(sock, LLCP_PDU_CONNECT, size);
436	if (skb == NULL) {
437		err = -ENOMEM;
438		goto error_tlv;
439	}
440
441	llcp_add_tlv(skb, service_name_tlv, service_name_tlv_length);
442	llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
443	llcp_add_tlv(skb, rw_tlv, rw_tlv_length);
444
445	skb_queue_tail(&local->tx_queue, skb);
446
447	err = 0;
448
449error_tlv:
450	if (err)
451		pr_err("error %d\n", err);
452
453	kfree(service_name_tlv);
454	kfree(miux_tlv);
455	kfree(rw_tlv);
456
457	return err;
458}
459
460int nfc_llcp_send_cc(struct nfc_llcp_sock *sock)
461{
462	struct nfc_llcp_local *local;
463	struct sk_buff *skb;
464	u8 *miux_tlv = NULL, miux_tlv_length;
465	u8 *rw_tlv = NULL, rw_tlv_length, rw;
466	int err;
467	u16 size = 0;
468	__be16 miux;
469
470	pr_debug("Sending CC\n");
471
472	local = sock->local;
473	if (local == NULL)
474		return -ENODEV;
475
476	/* If the socket parameters are not set, use the local ones */
477	miux = be16_to_cpu(sock->miux) > LLCP_MAX_MIUX ?
478		local->miux : sock->miux;
479	rw = sock->rw > LLCP_MAX_RW ? local->rw : sock->rw;
480
481	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
482				      &miux_tlv_length);
483	size += miux_tlv_length;
484
485	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
486	size += rw_tlv_length;
487
488	skb = llcp_allocate_pdu(sock, LLCP_PDU_CC, size);
489	if (skb == NULL) {
490		err = -ENOMEM;
491		goto error_tlv;
492	}
493
494	llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
495	llcp_add_tlv(skb, rw_tlv, rw_tlv_length);
496
497	skb_queue_tail(&local->tx_queue, skb);
498
499	err = 0;
500
501error_tlv:
502	if (err)
503		pr_err("error %d\n", err);
504
505	kfree(miux_tlv);
506	kfree(rw_tlv);
507
508	return err;
509}
510
511static struct sk_buff *nfc_llcp_allocate_snl(struct nfc_llcp_local *local,
512					     size_t tlv_length)
513{
514	struct sk_buff *skb;
515	struct nfc_dev *dev;
516	u16 size = 0;
517
518	if (local == NULL)
519		return ERR_PTR(-ENODEV);
520
521	dev = local->dev;
522	if (dev == NULL)
523		return ERR_PTR(-ENODEV);
524
525	size += LLCP_HEADER_SIZE;
526	size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
527	size += tlv_length;
528
529	skb = alloc_skb(size, GFP_KERNEL);
530	if (skb == NULL)
531		return ERR_PTR(-ENOMEM);
532
533	skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
534
535	skb = llcp_add_header(skb, LLCP_SAP_SDP, LLCP_SAP_SDP, LLCP_PDU_SNL);
536
537	return skb;
538}
539
540int nfc_llcp_send_snl_sdres(struct nfc_llcp_local *local,
541			    struct hlist_head *tlv_list, size_t tlvs_len)
542{
543	struct nfc_llcp_sdp_tlv *sdp;
544	struct hlist_node *n;
545	struct sk_buff *skb;
546
547	skb = nfc_llcp_allocate_snl(local, tlvs_len);
548	if (IS_ERR(skb))
549		return PTR_ERR(skb);
550
551	hlist_for_each_entry_safe(sdp, n, tlv_list, node) {
552		memcpy(skb_put(skb, sdp->tlv_len), sdp->tlv, sdp->tlv_len);
553
554		hlist_del(&sdp->node);
555
556		nfc_llcp_free_sdp_tlv(sdp);
557	}
558
559	skb_queue_tail(&local->tx_queue, skb);
560
561	return 0;
562}
563
564int nfc_llcp_send_snl_sdreq(struct nfc_llcp_local *local,
565			    struct hlist_head *tlv_list, size_t tlvs_len)
566{
567	struct nfc_llcp_sdp_tlv *sdreq;
568	struct hlist_node *n;
569	struct sk_buff *skb;
570
571	skb = nfc_llcp_allocate_snl(local, tlvs_len);
572	if (IS_ERR(skb))
573		return PTR_ERR(skb);
574
575	mutex_lock(&local->sdreq_lock);
576
577	if (hlist_empty(&local->pending_sdreqs))
578		mod_timer(&local->sdreq_timer,
579			  jiffies + msecs_to_jiffies(3 * local->remote_lto));
580
581	hlist_for_each_entry_safe(sdreq, n, tlv_list, node) {
582		pr_debug("tid %d for %s\n", sdreq->tid, sdreq->uri);
583
584		memcpy(skb_put(skb, sdreq->tlv_len), sdreq->tlv,
585		       sdreq->tlv_len);
586
587		hlist_del(&sdreq->node);
588
589		hlist_add_head(&sdreq->node, &local->pending_sdreqs);
590	}
591
592	mutex_unlock(&local->sdreq_lock);
593
594	skb_queue_tail(&local->tx_queue, skb);
595
596	return 0;
597}
598
599int nfc_llcp_send_dm(struct nfc_llcp_local *local, u8 ssap, u8 dsap, u8 reason)
600{
601	struct sk_buff *skb;
602	struct nfc_dev *dev;
603	u16 size = 1; /* Reason code */
604
605	pr_debug("Sending DM reason 0x%x\n", reason);
606
607	if (local == NULL)
608		return -ENODEV;
609
610	dev = local->dev;
611	if (dev == NULL)
612		return -ENODEV;
613
614	size += LLCP_HEADER_SIZE;
615	size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
616
617	skb = alloc_skb(size, GFP_KERNEL);
618	if (skb == NULL)
619		return -ENOMEM;
620
621	skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
622
623	skb = llcp_add_header(skb, dsap, ssap, LLCP_PDU_DM);
624
625	memcpy(skb_put(skb, 1), &reason, 1);
626
627	skb_queue_head(&local->tx_queue, skb);
628
629	return 0;
630}
631
632int nfc_llcp_send_i_frame(struct nfc_llcp_sock *sock,
633			  struct msghdr *msg, size_t len)
634{
635	struct sk_buff *pdu;
636	struct sock *sk = &sock->sk;
637	struct nfc_llcp_local *local;
638	size_t frag_len = 0, remaining_len;
639	u8 *msg_data, *msg_ptr;
640	u16 remote_miu;
641
642	pr_debug("Send I frame len %zd\n", len);
643
644	local = sock->local;
645	if (local == NULL)
646		return -ENODEV;
647
648	/* Remote is ready but has not acknowledged our frames */
649	if((sock->remote_ready &&
650	    skb_queue_len(&sock->tx_pending_queue) >= sock->remote_rw &&
651	    skb_queue_len(&sock->tx_queue) >= 2 * sock->remote_rw)) {
652		pr_err("Pending queue is full %d frames\n",
653		       skb_queue_len(&sock->tx_pending_queue));
654		return -ENOBUFS;
655	}
656
657	/* Remote is not ready and we've been queueing enough frames */
658	if ((!sock->remote_ready &&
659	     skb_queue_len(&sock->tx_queue) >= 2 * sock->remote_rw)) {
660		pr_err("Tx queue is full %d frames\n",
661		       skb_queue_len(&sock->tx_queue));
662		return -ENOBUFS;
663	}
664
665	msg_data = kmalloc(len, GFP_USER | __GFP_NOWARN);
666	if (msg_data == NULL)
667		return -ENOMEM;
668
669	if (memcpy_from_msg(msg_data, msg, len)) {
670		kfree(msg_data);
671		return -EFAULT;
672	}
673
674	remaining_len = len;
675	msg_ptr = msg_data;
676
677	do {
678		remote_miu = sock->remote_miu > LLCP_MAX_MIU ?
679				LLCP_DEFAULT_MIU : sock->remote_miu;
680
681		frag_len = min_t(size_t, remote_miu, remaining_len);
682
683		pr_debug("Fragment %zd bytes remaining %zd",
684			 frag_len, remaining_len);
685
686		pdu = llcp_allocate_pdu(sock, LLCP_PDU_I,
687					frag_len + LLCP_SEQUENCE_SIZE);
688		if (pdu == NULL) {
689			kfree(msg_data);
690			return -ENOMEM;
691		}
692
693		skb_put(pdu, LLCP_SEQUENCE_SIZE);
694
695		if (likely(frag_len > 0))
696			memcpy(skb_put(pdu, frag_len), msg_ptr, frag_len);
697
698		skb_queue_tail(&sock->tx_queue, pdu);
699
700		lock_sock(sk);
701
702		nfc_llcp_queue_i_frames(sock);
703
704		release_sock(sk);
705
706		remaining_len -= frag_len;
707		msg_ptr += frag_len;
708	} while (remaining_len > 0);
709
710	kfree(msg_data);
711
712	return len;
713}
714
715int nfc_llcp_send_ui_frame(struct nfc_llcp_sock *sock, u8 ssap, u8 dsap,
716			   struct msghdr *msg, size_t len)
717{
718	struct sk_buff *pdu;
719	struct nfc_llcp_local *local;
720	size_t frag_len = 0, remaining_len;
721	u8 *msg_ptr, *msg_data;
722	u16 remote_miu;
723	int err;
724
725	pr_debug("Send UI frame len %zd\n", len);
726
727	local = sock->local;
728	if (local == NULL)
729		return -ENODEV;
730
731	msg_data = kmalloc(len, GFP_USER | __GFP_NOWARN);
732	if (msg_data == NULL)
733		return -ENOMEM;
734
735	if (memcpy_from_msg(msg_data, msg, len)) {
736		kfree(msg_data);
737		return -EFAULT;
738	}
739
740	remaining_len = len;
741	msg_ptr = msg_data;
742
743	do {
744		remote_miu = sock->remote_miu > LLCP_MAX_MIU ?
745				local->remote_miu : sock->remote_miu;
746
747		frag_len = min_t(size_t, remote_miu, remaining_len);
748
749		pr_debug("Fragment %zd bytes remaining %zd",
750			 frag_len, remaining_len);
751
752		pdu = nfc_alloc_send_skb(sock->dev, &sock->sk, MSG_DONTWAIT,
753					 frag_len + LLCP_HEADER_SIZE, &err);
754		if (pdu == NULL) {
755			pr_err("Could not allocate PDU\n");
756			continue;
757		}
758
759		pdu = llcp_add_header(pdu, dsap, ssap, LLCP_PDU_UI);
760
761		if (likely(frag_len > 0))
762			memcpy(skb_put(pdu, frag_len), msg_ptr, frag_len);
763
764		/* No need to check for the peer RW for UI frames */
765		skb_queue_tail(&local->tx_queue, pdu);
766
767		remaining_len -= frag_len;
768		msg_ptr += frag_len;
769	} while (remaining_len > 0);
770
771	kfree(msg_data);
772
773	return len;
774}
775
776int nfc_llcp_send_rr(struct nfc_llcp_sock *sock)
777{
778	struct sk_buff *skb;
779	struct nfc_llcp_local *local;
780
781	pr_debug("Send rr nr %d\n", sock->recv_n);
782
783	local = sock->local;
784	if (local == NULL)
785		return -ENODEV;
786
787	skb = llcp_allocate_pdu(sock, LLCP_PDU_RR, LLCP_SEQUENCE_SIZE);
788	if (skb == NULL)
789		return -ENOMEM;
790
791	skb_put(skb, LLCP_SEQUENCE_SIZE);
792
793	skb->data[2] = sock->recv_n;
794
795	skb_queue_head(&local->tx_queue, skb);
796
797	return 0;
798}