net/nfc/llcp_commands.c - kernel/msm-4.9 - Gitiles

 /*
  * 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 = 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]);

 	memcpy(skb_put(pdu, LLCP_HEADER_SIZE), 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;

 	memcpy(skb_put(pdu, tlv_length), 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_LLCP_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, 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);
 		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);
 	size += miux_tlv_length;

 	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
 	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;
 	}

 	if (service_name_tlv != NULL)
 		skb = llcp_add_tlv(skb, service_name_tlv,
 				   service_name_tlv_length);

 	skb = llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
 	skb = llcp_add_tlv(skb, rw_tlv, rw_tlv_length);

 	skb_queue_tail(&local->tx_queue, skb);

 	return 0;

 error_tlv:
 	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, 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);
 	size += miux_tlv_length;

 	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
 	size += rw_tlv_length;

 	skb = llcp_allocate_pdu(sock, LLCP_PDU_CC, size);
 	if (skb == NULL) {
 		err = -ENOMEM;
 		goto error_tlv;
 	}

 	skb = llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
 	skb = llcp_add_tlv(skb, rw_tlv, rw_tlv_length);

 	skb_queue_tail(&local->tx_queue, skb);

 	return 0;

 error_tlv:
 	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) {
 		memcpy(skb_put(skb, sdp->tlv_len), 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);

 		memcpy(skb_put(skb, sdreq->tlv_len), 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);

 	memcpy(skb_put(skb, 1), &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 = kzalloc(len, GFP_KERNEL);
 	if (msg_data == NULL)
 		return -ENOMEM;

 	if (memcpy_fromiovec(msg_data, msg->msg_iov, 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 = llcp_allocate_pdu(sock, LLCP_PDU_I,
 					frag_len + LLCP_SEQUENCE_SIZE);
 		if (pdu == NULL)
 			return -ENOMEM;

 		skb_put(pdu, LLCP_SEQUENCE_SIZE);

 		if (likely(frag_len > 0))
 			memcpy(skb_put(pdu, frag_len), 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 = kzalloc(len, GFP_KERNEL);
 	if (msg_data == NULL)
 		return -ENOMEM;

 	if (memcpy_fromiovec(msg_data, msg->msg_iov, 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, MSG_DONTWAIT,
 					 frag_len + LLCP_HEADER_SIZE, &err);
 		if (pdu == NULL) {
 			pr_err("Could not allocate PDU\n");
 			continue;
 		}

 		pdu = llcp_add_header(pdu, dsap, ssap, LLCP_PDU_UI);

 		if (likely(frag_len > 0))
 			memcpy(skb_put(pdu, frag_len), 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;
 }
	/*
	* 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 = 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]);

	memcpy(skb_put(pdu, LLCP_HEADER_SIZE), 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;

	memcpy(skb_put(pdu, tlv_length), 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_LLCP_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, 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);
	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);
	size += miux_tlv_length;

	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
	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;
	}

	if (service_name_tlv != NULL)
	skb = llcp_add_tlv(skb, service_name_tlv,
	service_name_tlv_length);

	skb = llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
	skb = llcp_add_tlv(skb, rw_tlv, rw_tlv_length);

	skb_queue_tail(&local->tx_queue, skb);

	return 0;

	error_tlv:
	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, 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);
	size += miux_tlv_length;

	rw_tlv = nfc_llcp_build_tlv(LLCP_TLV_RW, &rw, 0, &rw_tlv_length);
	size += rw_tlv_length;

	skb = llcp_allocate_pdu(sock, LLCP_PDU_CC, size);
	if (skb == NULL) {
	err = -ENOMEM;
	goto error_tlv;
	}

	skb = llcp_add_tlv(skb, miux_tlv, miux_tlv_length);
	skb = llcp_add_tlv(skb, rw_tlv, rw_tlv_length);

	skb_queue_tail(&local->tx_queue, skb);

	return 0;

	error_tlv:
	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) {
	memcpy(skb_put(skb, sdp->tlv_len), 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);

	memcpy(skb_put(skb, sdreq->tlv_len), 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);

	memcpy(skb_put(skb, 1), &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 = kzalloc(len, GFP_KERNEL);
	if (msg_data == NULL)
	return -ENOMEM;

	if (memcpy_fromiovec(msg_data, msg->msg_iov, 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 = llcp_allocate_pdu(sock, LLCP_PDU_I,
	frag_len + LLCP_SEQUENCE_SIZE);
	if (pdu == NULL)
	return -ENOMEM;

	skb_put(pdu, LLCP_SEQUENCE_SIZE);

	if (likely(frag_len > 0))
	memcpy(skb_put(pdu, frag_len), 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 = kzalloc(len, GFP_KERNEL);
	if (msg_data == NULL)
	return -ENOMEM;

	if (memcpy_fromiovec(msg_data, msg->msg_iov, 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, MSG_DONTWAIT,
	frag_len + LLCP_HEADER_SIZE, &err);
	if (pdu == NULL) {
	pr_err("Could not allocate PDU\n");
	continue;
	}

	pdu = llcp_add_header(pdu, dsap, ssap, LLCP_PDU_UI);

	if (likely(frag_len > 0))
	memcpy(skb_put(pdu, frag_len), 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;
	}