text: /*
   * Copyright (C) 2011  Intel Corporation. All rights reserved.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, see <http://www.gnu.org/licenses/>.
   */
  
  #define pr_fmt(fmt) "llcp: %s: " fmt, __func__
  
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/nfc.h>
  
  #include <net/nfc/nfc.h>
  
  #include "nfc.h"
  #include "llcp.h"
  
  static u8 llcp_tlv_length[LLCP_TLV_MAX] = {
  	0,
  	1, /* VERSION */
  	2, /* MIUX */
  	2, /* WKS */
  	1, /* LTO */
  	1, /* RW */
  	0, /* SN */
  	1, /* OPT */
  	0, /* SDREQ */
  	2, /* SDRES */
  
  };
  
  static u8 llcp_tlv8(u8 *tlv, u8 type)
  {
  	if (tlv[0] != type || tlv[1] != llcp_tlv_length[tlv[0]])
  		return 0;
  
  	return tlv[2];
  }
  
  static u16 llcp_tlv16(u8 *tlv, u8 type)
  {
  	if (tlv[0] != type || tlv[1] != llcp_tlv_length[tlv[0]])
  		return 0;
  
  	return be16_to_cpu(*((__be16 *)(tlv + 2)));
  }
  
  
  static u8 llcp_tlv_version(u8 *tlv)
  {
  	return llcp_tlv8(tlv, LLCP_TLV_VERSION);
  }
  
  static u16 llcp_tlv_miux(u8 *tlv)
  {
  	return llcp_tlv16(tlv, LLCP_TLV_MIUX) & 0x7ff;
  }
  
  static u16 llcp_tlv_wks(u8 *tlv)
  {
  	return llcp_tlv16(tlv, LLCP_TLV_WKS);
  }
  
  static u16 llcp_tlv_lto(u8 *tlv)
  {
  	return llcp_tlv8(tlv, LLCP_TLV_LTO);
  }
  
  static u8 llcp_tlv_opt(u8 *tlv)
  {
  	return llcp_tlv8(tlv, LLCP_TLV_OPT);
  }
  
  static u8 llcp_tlv_rw(u8 *tlv)
  {
  	return llcp_tlv8(tlv, LLCP_TLV_RW) & 0xf;
  }
  
  u8 *nfc_llcp_build_tlv(u8 type, u8 *value, u8 value_length, u8 *tlv_length)
  {
  	u8 *tlv, length;
  
  	pr_debug("type %d\n", type);
  
  	if (type >= LLCP_TLV_MAX)
  		return NULL;
  
  	length = llcp_tlv_length[type];
  	if (length == 0 && value_length == 0)
  		return NULL;
  	else if (length == 0)
  		length = value_length;
  
  	*tlv_length = 2 + length;
  	tlv = kzalloc(2 + length, GFP_KERNEL);
  	if (tlv == NULL)
  		return tlv;
  
  	tlv[0] = type;
  	tlv[1] = length;
  	memcpy(tlv + 2, value, length);
  
  	return tlv;
  }
  
  struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdres_tlv(u8 tid, u8 sap)
  {
  	struct nfc_llcp_sdp_tlv *sdres;
  	u8 value[2];
  
  	sdres = kzalloc(sizeof(struct nfc_llcp_sdp_tlv), GFP_KERNEL);
  	if (sdres == NULL)
  		return NULL;
  
  	value[0] = tid;
  	value[1] = sap;
  
  	sdres->tlv = nfc_llcp_build_tlv(LLCP_TLV_SDRES, value, 2,
  					&sdres->tlv_len);
  	if (sdres->tlv == NULL) {
  		kfree(sdres);
  		return NULL;
  	}
  
  	sdres->tid = tid;
  	sdres->sap = sap;
  
  	INIT_HLIST_NODE(&sdres->node);
  
  	return sdres;
  }
  
  struct nfc_llcp_sdp_tlv *nfc_llcp_build_sdreq_tlv(u8 tid, char *uri,
  						  size_t uri_len)
  {
  	struct nfc_llcp_sdp_tlv *sdreq;
  
  	pr_debug("uri: %s, len: %zu\n", uri, uri_len);
  
  	/* sdreq->tlv_len is u8, takes uri_len, + 3 for header, + 1 for NULL */
  	if (WARN_ON_ONCE(uri_len > U8_MAX - 4))
  		return NULL;
  
  	sdreq = kzalloc(sizeof(struct nfc_llcp_sdp_tlv), GFP_KERNEL);
  	if (sdreq == NULL)
  		return NULL;
  
  	sdreq->tlv_len = uri_len + 3;
  
  	if (uri[uri_len - 1] == 0)
  		sdreq->tlv_len--;
  
  	sdreq->tlv = kzalloc(sdreq->tlv_len + 1, GFP_KERNEL);
  	if (sdreq->tlv == NULL) {
  		kfree(sdreq);
  		return NULL;
  	}
  
  	sdreq->tlv[0] = LLCP_TLV_SDREQ;
  	sdreq->tlv[1] = sdreq->tlv_len - 2;
  	sdreq->tlv[2] = tid;
  
  	sdreq->tid = tid;
  	sdreq->uri = sdreq->tlv + 3;
  	memcpy(sdreq->uri, uri, uri_len);
  
  	sdreq->time = jiffies;
  
  	INIT_HLIST_NODE(&sdreq->node);
  
  	return sdreq;
  }
  
  void nfc_llcp_free_sdp_tlv(struct nfc_llcp_sdp_tlv *sdp)
  {
  	kfree(sdp->tlv);
  	kfree(sdp);
  }
  
  void nfc_llcp_free_sdp_tlv_list(struct hlist_head *head)
  {
  	struct nfc_llcp_sdp_tlv *sdp;
  	struct hlist_node *n;
  
  	hlist_for_each_entry_safe(sdp, n, head, node) {
  		hlist_del(&sdp->node);
  
  		nfc_llcp_free_sdp_tlv(sdp);
  	}
  }
  
  int nfc_llcp_parse_gb_tlv(struct nfc_llcp_local *local,
  			  u8 *tlv_array, u16 tlv_array_len)
  {
  	u8 *tlv = tlv_array, type, length, offset = 0;
  
  	pr_debug("TLV array length %d\n", tlv_array_len);
  
  	if (local == NULL)
  		return -ENODEV;
  
  	while (offset < tlv_array_len) {
  		type = tlv[0];
  		length = tlv[1];
  
  		pr_debug("type 0x%x length %d\n", type, length);
  
  		switch (type) {
  		case LLCP_TLV_VERSION:
  			local->remote_version = llcp_tlv_version(tlv);
  			break;
  		case LLCP_TLV_MIUX:
  			local->remote_miu = llcp_tlv_miux(tlv) + 128;
  			break;
  		case LLCP_TLV_WKS:
  			local->remote_wks = llcp_tlv_wks(tlv);
  			break;
  		case LLCP_TLV_LTO:
  			local->remote_lto = llcp_tlv_lto(tlv) * 10;
  			break;
  		case LLCP_TLV_OPT:
  			local->remote_opt = llcp_tlv_opt(tlv);
  			break;
  		default:
  			pr_err("Invalid gt tlv value 0x%x\n", type);
  			break;
  		}
  
  		offset += length + 2;
  		tlv += length + 2;
  	}
  
  	pr_debug("version 0x%x miu %d lto %d opt 0x%x wks 0x%x\n",
  		 local->remote_version, local->remote_miu,
  		 local->remote_lto, local->remote_opt,
  		 local->remote_wks);
  
  	return 0;
  }
  
  int nfc_llcp_parse_connection_tlv(struct nfc_llcp_sock *sock,
  				  u8 *tlv_array, u16 tlv_array_len)
  {
  	u8 *tlv = tlv_array, type, length, offset = 0;
  
  	pr_debug("TLV array length %d\n", tlv_array_len);
  
  	if (sock == NULL)
  		return -ENOTCONN;
  
  	while (offset < tlv_array_len) {
  		type = tlv[0];
  		length = tlv[1];
  
  		pr_debug("type 0x%x length %d\n", type, length);
  
  		switch (type) {
  		case LLCP_TLV_MIUX:
  			sock->remote_miu = llcp_tlv_miux(tlv) + 128;
  			break;
  		case LLCP_TLV_RW:
  			sock->remote_rw = llcp_tlv_rw(tlv);
  			break;
  		case LLCP_TLV_SN:
  			break;
  		default:
  			pr_err("Invalid gt tlv value 0x%x\n", type);
  			break;
  		}
  
  		offset += length + 2;
  		tlv += length + 2;
  	}
  
  	pr_debug("sock %p rw %d miu %d\n", sock,
  		 sock->remote_rw, sock->remote_miu);
  
  	return 0;
  }
  
  static struct sk_buff *llcp_add_header(struct sk_buff *pdu,
  				       u8 dsap, u8 ssap, u8 ptype)
  {
  	u8 header[2];
  
  	pr_debug("ptype 0x%x dsap 0x%x ssap 0x%x\n", ptype, dsap, ssap);
  
  	header[0] = (u8)((dsap << 2) | (ptype >> 2));
  	header[1] = (u8)((ptype << 6) | ssap);
  
  	pr_debug("header 0x%x 0x%x\n", header[0], header[1]);
  
  	skb_put_data(pdu, header, LLCP_HEADER_SIZE);
  
  	return pdu;
  }
  
  static struct sk_buff *llcp_add_tlv(struct sk_buff *pdu, u8 *tlv,
  				    u8 tlv_length)
  {
  	/* XXX Add an skb length check */
  
  	if (tlv == NULL)
  		return NULL;
  
  	skb_put_data(pdu, tlv, tlv_length);
  
  	return pdu;
  }
  
  static struct sk_buff *llcp_allocate_pdu(struct nfc_llcp_sock *sock,
  					 u8 cmd, u16 size)
  {
  	struct sk_buff *skb;
  	int err;
  
  	if (sock->ssap == 0)
  		return NULL;
  
  	skb = nfc_alloc_send_skb(sock->dev, &sock->sk, MSG_DONTWAIT,
  				 size + LLCP_HEADER_SIZE, &err);
  	if (skb == NULL) {
  		pr_err("Could not allocate PDU\n");
  		return NULL;
  	}
  
  	skb = llcp_add_header(skb, sock->dsap, sock->ssap, cmd);
  
  	return skb;
  }
  
  int nfc_llcp_send_disconnect(struct nfc_llcp_sock *sock)
  {
  	struct sk_buff *skb;
  	struct nfc_dev *dev;
  	struct nfc_llcp_local *local;
  
  	pr_debug("Sending DISC\n");
  
  	local = sock->local;
  	if (local == NULL)
  		return -ENODEV;
  
  	dev = sock->dev;
  	if (dev == NULL)
  		return -ENODEV;
  
  	skb = llcp_allocate_pdu(sock, LLCP_PDU_DISC, 0);
  	if (skb == NULL)
  		return -ENOMEM;
  
  	skb_queue_tail(&local->tx_queue, skb);
  
  	return 0;
  }
  
  int nfc_llcp_send_symm(struct nfc_dev *dev)
  {
  	struct sk_buff *skb;
  	struct nfc_llcp_local *local;
  	u16 size = 0;
  
  	pr_debug("Sending SYMM\n");
  
  	local = nfc_llcp_find_local(dev);
  	if (local == NULL)
  		return -ENODEV;
  
  	size += LLCP_HEADER_SIZE;
  	size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
  
  	skb = alloc_skb(size, GFP_KERNEL);
  	if (skb == NULL)
  		return -ENOMEM;
  
  	skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
  
  	skb = llcp_add_header(skb, 0, 0, LLCP_PDU_SYMM);
  
  	__net_timestamp(skb);
  
  	nfc_llcp_send_to_raw_sock(local, skb, NFC_DIRECTION_TX);
  
  	return nfc_data_exchange(dev, local->target_idx, skb,
  				 nfc_llcp_recv, local);
  }
  
  int nfc_llcp_send_connect(struct nfc_llcp_sock *sock)
  {
  	struct nfc_llcp_local *local;
  	struct sk_buff *skb;
  	u8 *service_name_tlv = NULL, service_name_tlv_length;
  	u8 *miux_tlv = NULL, miux_tlv_length;
  	u8 *rw_tlv = NULL, rw_tlv_length, rw;
  	int err;
  	u16 size = 0;
  	__be16 miux;
  
  	pr_debug("Sending CONNECT\n");
  
  	local = sock->local;
  	if (local == NULL)
  		return -ENODEV;
  
  	if (sock->service_name != NULL) {
  		service_name_tlv = nfc_llcp_build_tlv(LLCP_TLV_SN,
  						      sock->service_name,
  						      sock->service_name_len,
  						      &service_name_tlv_length);
  		if (!service_name_tlv) {
  			err = -ENOMEM;
  			goto error_tlv;
  		}
  		size += service_name_tlv_length;
  	}
  
  	/* If the socket parameters are not set, use the local ones */
  	miux = be16_to_cpu(sock->miux) > LLCP_MAX_MIUX ?
  		local->miux : sock->miux;
  	rw = sock->rw > LLCP_MAX_RW ? local->rw : sock->rw;
  
  	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
  				      &miux_tlv_length);
  	if (!miux_tlv) {
  		err = -ENOMEM;
  		goto error_tlv;
  	}
  	size += miux_tlv_length;
  
  	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
  	if (!rw_tlv) {
  		err = -ENOMEM;
  		goto error_tlv;
  	}
  	size += rw_tlv_length;
  
  	pr_debug("SKB size %d SN length %zu\n", size, sock->service_name_len);
  
  	skb = llcp_allocate_pdu(sock, LLCP_PDU_CONNECT, size);
  	if (skb == NULL) {
  		err = -ENOMEM;
  		goto error_tlv;
  	}
  
  	llcp_add_tlv(skb, service_name_tlv, service_name_tlv_length);
  	llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
  	llcp_add_tlv(skb, rw_tlv, rw_tlv_length);
  
  	skb_queue_tail(&local->tx_queue, skb);
  
  	err = 0;
  
  error_tlv:
  	if (err)
  		pr_err("error %d\n", err);
  
  	kfree(service_name_tlv);
  	kfree(miux_tlv);
  	kfree(rw_tlv);
  
  	return err;
  }
  
  int nfc_llcp_send_cc(struct nfc_llcp_sock *sock)
  {
  	struct nfc_llcp_local *local;
  	struct sk_buff *skb;
  	u8 *miux_tlv = NULL, miux_tlv_length;
  	u8 *rw_tlv = NULL, rw_tlv_length, rw;
  	int err;
  	u16 size = 0;
  	__be16 miux;
  
  	pr_debug("Sending CC\n");
  
  	local = sock->local;
  	if (local == NULL)
  		return -ENODEV;
  
  	/* If the socket parameters are not set, use the local ones */
  	miux = be16_to_cpu(sock->miux) > LLCP_MAX_MIUX ?
  		local->miux : sock->miux;
  	rw = sock->rw > LLCP_MAX_RW ? local->rw : sock->rw;
  
  	miux_tlv = nfc_llcp_build_tlv(LLCP_TLV_MIUX, (u8 *)&miux, 0,
  				      &miux_tlv_length);
  	if (!miux_tlv) {
  		err = -ENOMEM;
  		goto error_tlv;
  	}
  	size += miux_tlv_length;
  
  	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
  	if (!rw_tlv) {
  		err = -ENOMEM;
  		goto error_tlv;
  	}
  	size += rw_tlv_length;
  
  	skb = llcp_allocate_pdu(sock, LLCP_PDU_CC, size);
  	if (skb == NULL) {
  		err = -ENOMEM;
  		goto error_tlv;
  	}
  
  	llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
  	llcp_add_tlv(skb, rw_tlv, rw_tlv_length);
  
  	skb_queue_tail(&local->tx_queue, skb);
  
  	err = 0;
  
  error_tlv:
  	if (err)
  		pr_err("error %d\n", err);
  
  	kfree(miux_tlv);
  	kfree(rw_tlv);
  
  	return err;
  }
  
  static struct sk_buff *nfc_llcp_allocate_snl(struct nfc_llcp_local *local,
  					     size_t tlv_length)
  {
  	struct sk_buff *skb;
  	struct nfc_dev *dev;
  	u16 size = 0;
  
  	if (local == NULL)
  		return ERR_PTR(-ENODEV);
  
  	dev = local->dev;
  	if (dev == NULL)
  		return ERR_PTR(-ENODEV);
  
  	size += LLCP_HEADER_SIZE;
  	size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
  	size += tlv_length;
  
  	skb = alloc_skb(size, GFP_KERNEL);
  	if (skb == NULL)
  		return ERR_PTR(-ENOMEM);
  
  	skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
  
  	skb = llcp_add_header(skb, LLCP_SAP_SDP, LLCP_SAP_SDP, LLCP_PDU_SNL);
  
  	return skb;
  }
  
  int nfc_llcp_send_snl_sdres(struct nfc_llcp_local *local,
  			    struct hlist_head *tlv_list, size_t tlvs_len)
  {
  	struct nfc_llcp_sdp_tlv *sdp;
  	struct hlist_node *n;
  	struct sk_buff *skb;
  
  	skb = nfc_llcp_allocate_snl(local, tlvs_len);
  	if (IS_ERR(skb))
  		return PTR_ERR(skb);
  
  	hlist_for_each_entry_safe(sdp, n, tlv_list, node) {
  		skb_put_data(skb, sdp->tlv, sdp->tlv_len);
  
  		hlist_del(&sdp->node);
  
  		nfc_llcp_free_sdp_tlv(sdp);
  	}
  
  	skb_queue_tail(&local->tx_queue, skb);
  
  	return 0;
  }
  
  int nfc_llcp_send_snl_sdreq(struct nfc_llcp_local *local,
  			    struct hlist_head *tlv_list, size_t tlvs_len)
  {
  	struct nfc_llcp_sdp_tlv *sdreq;
  	struct hlist_node *n;
  	struct sk_buff *skb;
  
  	skb = nfc_llcp_allocate_snl(local, tlvs_len);
  	if (IS_ERR(skb))
  		return PTR_ERR(skb);
  
  	mutex_lock(&local->sdreq_lock);
  
  	if (hlist_empty(&local->pending_sdreqs))
  		mod_timer(&local->sdreq_timer,
  			  jiffies + msecs_to_jiffies(3 * local->remote_lto));
  
  	hlist_for_each_entry_safe(sdreq, n, tlv_list, node) {
  		pr_debug("tid %d for %s\n", sdreq->tid, sdreq->uri);
  
  		skb_put_data(skb, sdreq->tlv, sdreq->tlv_len);
  
  		hlist_del(&sdreq->node);
  
  		hlist_add_head(&sdreq->node, &local->pending_sdreqs);
  	}
  
  	mutex_unlock(&local->sdreq_lock);
  
  	skb_queue_tail(&local->tx_queue, skb);
  
  	return 0;
  }
  
  int nfc_llcp_send_dm(struct nfc_llcp_local *local, u8 ssap, u8 dsap, u8 reason)
  {
  	struct sk_buff *skb;
  	struct nfc_dev *dev;
  	u16 size = 1; /* Reason code */
  
  	pr_debug("Sending DM reason 0x%x\n", reason);
  
  	if (local == NULL)
  		return -ENODEV;
  
  	dev = local->dev;
  	if (dev == NULL)
  		return -ENODEV;
  
  	size += LLCP_HEADER_SIZE;
  	size += dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
  
  	skb = alloc_skb(size, GFP_KERNEL);
  	if (skb == NULL)
  		return -ENOMEM;
  
  	skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
  
  	skb = llcp_add_header(skb, dsap, ssap, LLCP_PDU_DM);
  
  	skb_put_data(skb, &reason, 1);
  
  	skb_queue_head(&local->tx_queue, skb);
  
  	return 0;
  }
  
  int nfc_llcp_send_i_frame(struct nfc_llcp_sock *sock,
  			  struct msghdr *msg, size_t len)
  {
  	struct sk_buff *pdu;
  	struct sock *sk = &sock->sk;
  	struct nfc_llcp_local *local;
  	size_t frag_len = 0, remaining_len;
  	u8 *msg_data, *msg_ptr;
  	u16 remote_miu;
  
  	pr_debug("Send I frame len %zd\n", len);
  
  	local = sock->local;
  	if (local == NULL)
  		return -ENODEV;
  
  	/* Remote is ready but has not acknowledged our frames */
  	if((sock->remote_ready &&
  	    skb_queue_len(&sock->tx_pending_queue) >= sock->remote_rw &&
  	    skb_queue_len(&sock->tx_queue) >= 2 * sock->remote_rw)) {
  		pr_err("Pending queue is full %d frames\n",
  		       skb_queue_len(&sock->tx_pending_queue));
  		return -ENOBUFS;
  	}
  
  	/* Remote is not ready and we've been queueing enough frames */
  	if ((!sock->remote_ready &&
  	     skb_queue_len(&sock->tx_queue) >= 2 * sock->remote_rw)) {
  		pr_err("Tx queue is full %d frames\n",
  		       skb_queue_len(&sock->tx_queue));
  		return -ENOBUFS;
  	}
  
  	msg_data = kmalloc(len, GFP_USER | __GFP_NOWARN);
  	if (msg_data == NULL)
  		return -ENOMEM;
  
  	if (memcpy_from_msg(msg_data, msg, len)) {
  		kfree(msg_data);
  		return -EFAULT;
  	}
  
  	remaining_len = len;
  	msg_ptr = msg_data;
  
  	do {
  		remote_miu = sock->remote_miu > LLCP_MAX_MIU ?
  				LLCP_DEFAULT_MIU : sock->remote_miu;
  
  		frag_len = min_t(size_t, remote_miu, remaining_len);
  
  		pr_debug("Fragment %zd bytes remaining %zd",
  			 frag_len, remaining_len);
  
  		pdu = llcp_allocate_pdu(sock, LLCP_PDU_I,
  					frag_len + LLCP_SEQUENCE_SIZE);
  		if (pdu == NULL) {
  			kfree(msg_data);
  			return -ENOMEM;
  		}
  
  		skb_put(pdu, LLCP_SEQUENCE_SIZE);
  
  		if (likely(frag_len > 0))
  			skb_put_data(pdu, msg_ptr, frag_len);
  
  		skb_queue_tail(&sock->tx_queue, pdu);
  
  		lock_sock(sk);
  
  		nfc_llcp_queue_i_frames(sock);
  
  		release_sock(sk);
  
  		remaining_len -= frag_len;
  		msg_ptr += frag_len;
  	} while (remaining_len > 0);
  
  	kfree(msg_data);
  
  	return len;
  }
  
  int nfc_llcp_send_ui_frame(struct nfc_llcp_sock *sock, u8 ssap, u8 dsap,
  			   struct msghdr *msg, size_t len)
  {
  	struct sk_buff *pdu;
  	struct nfc_llcp_local *local;
  	size_t frag_len = 0, remaining_len;
  	u8 *msg_ptr, *msg_data;
  	u16 remote_miu;
  	int err;
  
  	pr_debug("Send UI frame len %zd\n", len);
  
  	local = sock->local;
  	if (local == NULL)
  		return -ENODEV;
  
  	msg_data = kmalloc(len, GFP_USER | __GFP_NOWARN);
  	if (msg_data == NULL)
  		return -ENOMEM;
  
  	if (memcpy_from_msg(msg_data, msg, len)) {
  		kfree(msg_data);
  		return -EFAULT;
  	}
  
  	remaining_len = len;
  	msg_ptr = msg_data;
  
  	do {
  		remote_miu = sock->remote_miu > LLCP_MAX_MIU ?
  				local->remote_miu : sock->remote_miu;
  
  		frag_len = min_t(size_t, remote_miu, remaining_len);
  
  		pr_debug("Fragment %zd bytes remaining %zd",
  			 frag_len, remaining_len);
  
  		pdu = nfc_alloc_send_skb(sock->dev, &sock->sk, 0,
  					 frag_len + LLCP_HEADER_SIZE, &err);
  		if (pdu == NULL) {
  			pr_err("Could not allocate PDU (error=%d)\n", err);
  			len -= remaining_len;
  			if (len == 0)
  				len = err;
  			break;
  		}
  
  		pdu = llcp_add_header(pdu, dsap, ssap, LLCP_PDU_UI);
  
  		if (likely(frag_len > 0))
  			skb_put_data(pdu, msg_ptr, frag_len);
  
  		/* No need to check for the peer RW for UI frames */
  		skb_queue_tail(&local->tx_queue, pdu);
  
  		remaining_len -= frag_len;
  		msg_ptr += frag_len;
  	} while (remaining_len > 0);
  
  	kfree(msg_data);
  
  	return len;
  }
  
  int nfc_llcp_send_rr(struct nfc_llcp_sock *sock)
  {
  	struct sk_buff *skb;
  	struct nfc_llcp_local *local;
  
  	pr_debug("Send rr nr %d\n", sock->recv_n);
  
  	local = sock->local;
  	if (local == NULL)
  		return -ENODEV;
  
  	skb = llcp_allocate_pdu(sock, LLCP_PDU_RR, LLCP_SEQUENCE_SIZE);
  	if (skb == NULL)
  		return -ENOMEM;
  
  	skb_put(skb, LLCP_SEQUENCE_SIZE);
  
  	skb->data[2] = sock->recv_n;
  
  	skb_queue_head(&local->tx_queue, skb);
  
  	return 0;
  }
  