NFC: Initial LLCP support

This patch is an initial implementation for the NFC Logical Link Control
protocol. It's also known as NFC peer to peer mode.
This is a basic implementation as it lacks SDP (services Discovery
Protocol), frames aggregation support, and frame rejecion parsing.
Follow up patches will implement those missing features.
This code has been tested against a Nexus S phone implementing LLCP 1.0.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/nfc/llcp/llcp.c b/net/nfc/llcp/llcp.c
new file mode 100644
index 0000000..67756b2
--- /dev/null
+++ b/net/nfc/llcp/llcp.c
@@ -0,0 +1,973 @@
+/*
+ * 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, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#define pr_fmt(fmt) "llcp: %s: " fmt, __func__
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/nfc.h>
+
+#include "../nfc.h"
+#include "llcp.h"
+
+static u8 llcp_magic[3] = {0x46, 0x66, 0x6d};
+
+static struct list_head llcp_devices;
+
+static void nfc_llcp_socket_release(struct nfc_llcp_local *local)
+{
+	struct nfc_llcp_sock *parent, *s, *n;
+	struct sock *sk, *parent_sk;
+	int i;
+
+
+	mutex_lock(&local->socket_lock);
+
+	for (i = 0; i < LLCP_MAX_SAP; i++) {
+		parent = local->sockets[i];
+		if (parent == NULL)
+			continue;
+
+		/* Release all child sockets */
+		list_for_each_entry_safe(s, n, &parent->list, list) {
+			list_del(&s->list);
+			sk = &s->sk;
+
+			lock_sock(sk);
+
+			if (sk->sk_state == LLCP_CONNECTED)
+				nfc_put_device(s->dev);
+
+			sk->sk_state = LLCP_CLOSED;
+			sock_set_flag(sk, SOCK_DEAD);
+
+			release_sock(sk);
+		}
+
+		parent_sk = &parent->sk;
+
+		lock_sock(parent_sk);
+
+		if (parent_sk->sk_state == LLCP_LISTEN) {
+			struct nfc_llcp_sock *lsk, *n;
+			struct sock *accept_sk;
+
+			list_for_each_entry_safe(lsk, n, &parent->accept_queue,
+								accept_queue) {
+				accept_sk = &lsk->sk;
+				lock_sock(accept_sk);
+
+				nfc_llcp_accept_unlink(accept_sk);
+
+				accept_sk->sk_state = LLCP_CLOSED;
+				sock_set_flag(accept_sk, SOCK_DEAD);
+
+				release_sock(accept_sk);
+
+				sock_orphan(accept_sk);
+			}
+		}
+
+		if (parent_sk->sk_state == LLCP_CONNECTED)
+			nfc_put_device(parent->dev);
+
+		parent_sk->sk_state = LLCP_CLOSED;
+		sock_set_flag(parent_sk, SOCK_DEAD);
+
+		release_sock(parent_sk);
+	}
+
+	mutex_unlock(&local->socket_lock);
+}
+
+static void nfc_llcp_timeout_work(struct work_struct *work)
+{
+	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
+							timeout_work);
+
+	nfc_dep_link_down(local->dev);
+}
+
+static void nfc_llcp_symm_timer(unsigned long data)
+{
+	struct nfc_llcp_local *local = (struct nfc_llcp_local *) data;
+
+	pr_err("SYMM timeout\n");
+
+	queue_work(local->timeout_wq, &local->timeout_work);
+}
+
+struct nfc_llcp_local *nfc_llcp_find_local(struct nfc_dev *dev)
+{
+	struct nfc_llcp_local *local, *n;
+
+	list_for_each_entry_safe(local, n, &llcp_devices, list)
+		if (local->dev == dev)
+			return local;
+
+	pr_debug("No device found\n");
+
+	return NULL;
+}
+
+static char *wks[] = {
+	NULL,
+	NULL, /* SDP */
+	"urn:nfc:sn:ip",
+	"urn:nfc:sn:obex",
+	"urn:nfc:sn:snep",
+};
+
+static int nfc_llcp_wks_sap(char *service_name, size_t service_name_len)
+{
+	int sap, num_wks;
+
+	pr_debug("%s\n", service_name);
+
+	if (service_name == NULL)
+		return -EINVAL;
+
+	num_wks = ARRAY_SIZE(wks);
+
+	for (sap = 0 ; sap < num_wks; sap++) {
+		if (wks[sap] == NULL)
+			continue;
+
+		if (strncmp(wks[sap], service_name, service_name_len) == 0)
+			return sap;
+	}
+
+	return -EINVAL;
+}
+
+u8 nfc_llcp_get_sdp_ssap(struct nfc_llcp_local *local,
+				struct nfc_llcp_sock *sock)
+{
+	mutex_lock(&local->sdp_lock);
+
+	if (sock->service_name != NULL && sock->service_name_len > 0) {
+		int ssap = nfc_llcp_wks_sap(sock->service_name,
+						sock->service_name_len);
+
+		if (ssap > 0) {
+			pr_debug("WKS %d\n", ssap);
+
+			/* This is a WKS, let's check if it's free */
+			if (local->local_wks & BIT(ssap)) {
+				mutex_unlock(&local->sdp_lock);
+
+				return LLCP_SAP_MAX;
+			}
+
+			set_bit(BIT(ssap), &local->local_wks);
+			mutex_unlock(&local->sdp_lock);
+
+			return ssap;
+		}
+
+		/*
+		 * This is not a well known service,
+		 * we should try to find a local SDP free spot
+		 */
+		ssap = find_first_zero_bit(&local->local_sdp, LLCP_SDP_NUM_SAP);
+		if (ssap == LLCP_SDP_NUM_SAP) {
+			mutex_unlock(&local->sdp_lock);
+
+			return LLCP_SAP_MAX;
+		}
+
+		pr_debug("SDP ssap %d\n", LLCP_WKS_NUM_SAP + ssap);
+
+		set_bit(BIT(ssap), &local->local_sdp);
+		mutex_unlock(&local->sdp_lock);
+
+		return LLCP_WKS_NUM_SAP + ssap;
+
+	} else if (sock->ssap != 0) {
+		if (sock->ssap < LLCP_WKS_NUM_SAP) {
+			if (!(local->local_wks & BIT(sock->ssap))) {
+				set_bit(BIT(sock->ssap), &local->local_wks);
+				mutex_unlock(&local->sdp_lock);
+
+				return sock->ssap;
+			}
+
+		} else if (sock->ssap < LLCP_SDP_NUM_SAP) {
+			if (!(local->local_sdp &
+				BIT(sock->ssap - LLCP_WKS_NUM_SAP))) {
+				set_bit(BIT(sock->ssap - LLCP_WKS_NUM_SAP),
+							&local->local_sdp);
+				mutex_unlock(&local->sdp_lock);
+
+				return sock->ssap;
+			}
+		}
+	}
+
+	mutex_unlock(&local->sdp_lock);
+
+	return LLCP_SAP_MAX;
+}
+
+u8 nfc_llcp_get_local_ssap(struct nfc_llcp_local *local)
+{
+	u8 local_ssap;
+
+	mutex_lock(&local->sdp_lock);
+
+	local_ssap = find_first_zero_bit(&local->local_sap, LLCP_LOCAL_NUM_SAP);
+	if (local_ssap == LLCP_LOCAL_NUM_SAP) {
+		mutex_unlock(&local->sdp_lock);
+		return LLCP_SAP_MAX;
+	}
+
+	set_bit(BIT(local_ssap), &local->local_sap);
+
+	mutex_unlock(&local->sdp_lock);
+
+	return local_ssap + LLCP_LOCAL_SAP_OFFSET;
+}
+
+void nfc_llcp_put_ssap(struct nfc_llcp_local *local, u8 ssap)
+{
+	u8 local_ssap;
+	unsigned long *sdp;
+
+	if (ssap < LLCP_WKS_NUM_SAP) {
+		local_ssap = ssap;
+		sdp = &local->local_wks;
+	} else if (ssap < LLCP_LOCAL_NUM_SAP) {
+		local_ssap = ssap - LLCP_WKS_NUM_SAP;
+		sdp = &local->local_sdp;
+	} else if (ssap < LLCP_MAX_SAP) {
+		local_ssap = ssap - LLCP_LOCAL_NUM_SAP;
+		sdp = &local->local_sap;
+	} else {
+		return;
+	}
+
+	mutex_lock(&local->sdp_lock);
+
+	clear_bit(1 << local_ssap, sdp);
+
+	mutex_unlock(&local->sdp_lock);
+}
+
+u8 *nfc_llcp_general_bytes(struct nfc_dev *dev, u8 *general_bytes_len)
+{
+	struct nfc_llcp_local *local;
+
+	local = nfc_llcp_find_local(dev);
+	if (local == NULL) {
+		*general_bytes_len = 0;
+		return NULL;
+	}
+
+	*general_bytes_len = local->gb_len;
+
+	return local->gb;
+}
+
+static int nfc_llcp_build_gb(struct nfc_llcp_local *local)
+{
+	u8 *gb_cur, *version_tlv, version, version_length;
+	u8 *lto_tlv, lto, lto_length;
+	u8 *wks_tlv, wks_length;
+	u8 gb_len = 0;
+
+	version = LLCP_VERSION_11;
+	version_tlv = nfc_llcp_build_tlv(LLCP_TLV_VERSION, &version,
+							1, &version_length);
+	gb_len += version_length;
+
+	/* 1500 ms */
+	lto = 150;
+	lto_tlv = nfc_llcp_build_tlv(LLCP_TLV_VERSION, &lto, 1, &lto_length);
+	gb_len += lto_length;
+
+	pr_debug("Local wks 0x%lx\n", local->local_wks);
+	wks_tlv = nfc_llcp_build_tlv(LLCP_TLV_WKS, (u8 *)&local->local_wks, 2,
+								&wks_length);
+	gb_len += wks_length;
+
+	gb_len += ARRAY_SIZE(llcp_magic);
+
+	if (gb_len > NFC_MAX_GT_LEN) {
+		kfree(version_tlv);
+		return -EINVAL;
+	}
+
+	gb_cur = local->gb;
+
+	memcpy(gb_cur, llcp_magic, ARRAY_SIZE(llcp_magic));
+	gb_cur += ARRAY_SIZE(llcp_magic);
+
+	memcpy(gb_cur, version_tlv, version_length);
+	gb_cur += version_length;
+
+	memcpy(gb_cur, lto_tlv, lto_length);
+	gb_cur += lto_length;
+
+	memcpy(gb_cur, wks_tlv, wks_length);
+	gb_cur += wks_length;
+
+	kfree(version_tlv);
+	kfree(lto_tlv);
+
+	local->gb_len = gb_len;
+
+	return 0;
+}
+
+int nfc_llcp_set_remote_gb(struct nfc_dev *dev, u8 *gb, u8 gb_len)
+{
+	struct nfc_llcp_local *local = nfc_llcp_find_local(dev);
+
+	if (local == NULL) {
+		pr_err("No LLCP device\n");
+		return -ENODEV;
+	}
+
+	memset(local->remote_gb, 0, NFC_MAX_GT_LEN);
+	memcpy(local->remote_gb, gb, gb_len);
+	local->remote_gb_len = gb_len;
+
+	if (local->remote_gb == NULL ||
+			local->remote_gb_len == 0)
+		return -ENODEV;
+
+	if (memcmp(local->remote_gb, llcp_magic, 3)) {
+		pr_err("MAC does not support LLCP\n");
+		return -EINVAL;
+	}
+
+	return nfc_llcp_parse_tlv(local,
+			&local->remote_gb[3], local->remote_gb_len - 3);
+}
+
+static void nfc_llcp_tx_work(struct work_struct *work)
+{
+	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
+							tx_work);
+	struct sk_buff *skb;
+
+	skb = skb_dequeue(&local->tx_queue);
+	if (skb != NULL) {
+		pr_debug("Sending pending skb\n");
+		nfc_data_exchange(local->dev, local->target_idx,
+					skb, nfc_llcp_recv, local);
+	} else {
+		nfc_llcp_send_symm(local->dev);
+	}
+
+	mod_timer(&local->link_timer,
+			jiffies + msecs_to_jiffies(local->remote_lto));
+}
+
+static u8 nfc_llcp_dsap(struct sk_buff *pdu)
+{
+	return (pdu->data[0] & 0xfc) >> 2;
+}
+
+static u8 nfc_llcp_ptype(struct sk_buff *pdu)
+{
+	return ((pdu->data[0] & 0x03) << 2) | ((pdu->data[1] & 0xc0) >> 6);
+}
+
+static u8 nfc_llcp_ssap(struct sk_buff *pdu)
+{
+	return pdu->data[1] & 0x3f;
+}
+
+static u8 nfc_llcp_ns(struct sk_buff *pdu)
+{
+	return pdu->data[2] >> 4;
+}
+
+static u8 nfc_llcp_nr(struct sk_buff *pdu)
+{
+	return pdu->data[2] & 0xf;
+}
+
+static void nfc_llcp_set_nrns(struct nfc_llcp_sock *sock, struct sk_buff *pdu)
+{
+	pdu->data[2] = (sock->send_n << 4) | ((sock->recv_n - 1) % 16);
+	sock->send_n = (sock->send_n + 1) % 16;
+	sock->recv_ack_n = (sock->recv_n - 1) % 16;
+}
+
+static struct nfc_llcp_sock *nfc_llcp_sock_get(struct nfc_llcp_local *local,
+						u8 ssap, u8 dsap)
+{
+	struct nfc_llcp_sock *sock, *llcp_sock, *n;
+
+	if (ssap == 0 && dsap == 0)
+		return NULL;
+
+	mutex_lock(&local->socket_lock);
+	sock = local->sockets[ssap];
+	if (sock == NULL) {
+		mutex_unlock(&local->socket_lock);
+		return NULL;
+	}
+
+	pr_debug("root dsap %d (%d)\n", sock->dsap, dsap);
+
+	if (sock->dsap == dsap) {
+		sock_hold(&sock->sk);
+		mutex_unlock(&local->socket_lock);
+		return sock;
+	}
+
+	list_for_each_entry_safe(llcp_sock, n, &sock->list, list) {
+		pr_debug("llcp_sock %p sk %p dsap %d\n", llcp_sock,
+				&llcp_sock->sk, llcp_sock->dsap);
+		if (llcp_sock->dsap == dsap) {
+			sock_hold(&llcp_sock->sk);
+			mutex_unlock(&local->socket_lock);
+			return llcp_sock;
+		}
+	}
+
+	pr_err("Could not find socket for %d %d\n", ssap, dsap);
+
+	mutex_unlock(&local->socket_lock);
+
+	return NULL;
+}
+
+static void nfc_llcp_sock_put(struct nfc_llcp_sock *sock)
+{
+	sock_put(&sock->sk);
+}
+
+static u8 *nfc_llcp_connect_sn(struct sk_buff *skb, size_t *sn_len)
+{
+	u8 *tlv = &skb->data[2], type, length;
+	size_t tlv_array_len = skb->len - LLCP_HEADER_SIZE, offset = 0;
+
+	while (offset < tlv_array_len) {
+		type = tlv[0];
+		length = tlv[1];
+
+		pr_debug("type 0x%x length %d\n", type, length);
+
+		if (type == LLCP_TLV_SN) {
+			*sn_len = length;
+			return &tlv[2];
+		}
+
+		offset += length + 2;
+		tlv += length + 2;
+	}
+
+	return NULL;
+}
+
+static void nfc_llcp_recv_connect(struct nfc_llcp_local *local,
+				struct sk_buff *skb)
+{
+	struct sock *new_sk, *parent;
+	struct nfc_llcp_sock *sock, *new_sock;
+	u8 dsap, ssap, bound_sap, reason;
+
+	dsap = nfc_llcp_dsap(skb);
+	ssap = nfc_llcp_ssap(skb);
+
+	pr_debug("%d %d\n", dsap, ssap);
+
+	nfc_llcp_parse_tlv(local, &skb->data[LLCP_HEADER_SIZE],
+				skb->len - LLCP_HEADER_SIZE);
+
+	if (dsap != LLCP_SAP_SDP) {
+		bound_sap = dsap;
+
+		mutex_lock(&local->socket_lock);
+		sock = local->sockets[dsap];
+		if (sock == NULL) {
+			mutex_unlock(&local->socket_lock);
+			reason = LLCP_DM_NOBOUND;
+			goto fail;
+		}
+
+		sock_hold(&sock->sk);
+		mutex_unlock(&local->socket_lock);
+
+		lock_sock(&sock->sk);
+
+		if (sock->dsap == LLCP_SAP_SDP &&
+				sock->sk.sk_state == LLCP_LISTEN)
+			goto enqueue;
+	} else {
+		u8 *sn;
+		size_t sn_len;
+
+		sn = nfc_llcp_connect_sn(skb, &sn_len);
+		if (sn == NULL) {
+			reason = LLCP_DM_NOBOUND;
+			goto fail;
+		}
+
+		pr_debug("Service name length %zu\n", sn_len);
+
+		mutex_lock(&local->socket_lock);
+		for (bound_sap = 0; bound_sap < LLCP_LOCAL_SAP_OFFSET;
+								bound_sap++) {
+			sock = local->sockets[bound_sap];
+			if (sock == NULL)
+				continue;
+
+			if (sock->service_name == NULL ||
+				sock->service_name_len == 0)
+					continue;
+
+			if (sock->service_name_len != sn_len)
+				continue;
+
+			if (sock->dsap == LLCP_SAP_SDP &&
+					sock->sk.sk_state == LLCP_LISTEN &&
+					!memcmp(sn, sock->service_name, sn_len)) {
+				pr_debug("Found service name at SAP %d\n",
+								bound_sap);
+				sock_hold(&sock->sk);
+				mutex_unlock(&local->socket_lock);
+
+				lock_sock(&sock->sk);
+
+				goto enqueue;
+			}
+		}
+
+	}
+
+	mutex_unlock(&local->socket_lock);
+
+	reason = LLCP_DM_NOBOUND;
+	goto fail;
+
+enqueue:
+	parent = &sock->sk;
+
+	if (sk_acceptq_is_full(parent)) {
+		reason = LLCP_DM_REJ;
+		release_sock(&sock->sk);
+		sock_put(&sock->sk);
+		goto fail;
+	}
+
+	new_sk = nfc_llcp_sock_alloc(NULL, parent->sk_type,
+				     GFP_ATOMIC);
+	if (new_sk == NULL) {
+		reason = LLCP_DM_REJ;
+		release_sock(&sock->sk);
+		sock_put(&sock->sk);
+		goto fail;
+	}
+
+	new_sock = nfc_llcp_sock(new_sk);
+	new_sock->dev = local->dev;
+	new_sock->local = local;
+	new_sock->nfc_protocol = sock->nfc_protocol;
+	new_sock->ssap = bound_sap;
+	new_sock->dsap = ssap;
+	new_sock->parent = parent;
+
+	pr_debug("new sock %p sk %p\n", new_sock, &new_sock->sk);
+
+	list_add_tail(&new_sock->list, &sock->list);
+
+	nfc_llcp_accept_enqueue(&sock->sk, new_sk);
+
+	nfc_get_device(local->dev->idx);
+
+	new_sk->sk_state = LLCP_CONNECTED;
+
+	/* Wake the listening processes */
+	parent->sk_data_ready(parent, 0);
+
+	/* Send CC */
+	nfc_llcp_send_cc(new_sock);
+
+	release_sock(&sock->sk);
+	sock_put(&sock->sk);
+
+	return;
+
+fail:
+	/* Send DM */
+	nfc_llcp_send_dm(local, dsap, ssap, reason);
+
+	return;
+
+}
+
+static void nfc_llcp_recv_hdlc(struct nfc_llcp_local *local,
+				struct sk_buff *skb)
+{
+	struct nfc_llcp_sock *llcp_sock;
+	struct sock *sk;
+	u8 dsap, ssap, ptype, ns, nr;
+
+	ptype = nfc_llcp_ptype(skb);
+	dsap = nfc_llcp_dsap(skb);
+	ssap = nfc_llcp_ssap(skb);
+	ns = nfc_llcp_ns(skb);
+	nr = nfc_llcp_nr(skb);
+
+	pr_debug("%d %d R %d S %d\n", dsap, ssap, nr, ns);
+
+	llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
+	if (llcp_sock == NULL) {
+		nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);
+		return;
+	}
+
+	sk = &llcp_sock->sk;
+	lock_sock(sk);
+	if (sk->sk_state == LLCP_CLOSED) {
+		release_sock(sk);
+		nfc_llcp_sock_put(llcp_sock);
+	}
+
+	if (ns == llcp_sock->recv_n)
+		llcp_sock->recv_n = (llcp_sock->recv_n + 1) % 16;
+	else
+		pr_err("Received out of sequence I PDU\n");
+
+	/* Pass the payload upstream */
+	if (ptype == LLCP_PDU_I) {
+		pr_debug("I frame, queueing on %p\n", &llcp_sock->sk);
+
+		skb_pull(skb, LLCP_HEADER_SIZE + LLCP_SEQUENCE_SIZE);
+		if (sock_queue_rcv_skb(&llcp_sock->sk, skb)) {
+			pr_err("receive queue is full\n");
+			skb_queue_head(&llcp_sock->tx_backlog_queue, skb);
+		}
+	}
+
+	/* Remove skbs from the pending queue */
+	if (llcp_sock->send_ack_n != nr) {
+		struct sk_buff *s, *tmp;
+
+		llcp_sock->send_ack_n = nr;
+
+		skb_queue_walk_safe(&llcp_sock->tx_pending_queue, s, tmp)
+			if (nfc_llcp_ns(s) <= nr) {
+				skb_unlink(s, &llcp_sock->tx_pending_queue);
+				kfree_skb(s);
+			}
+	}
+
+	/* Queue some I frames for transmission */
+	while (llcp_sock->remote_ready &&
+		skb_queue_len(&llcp_sock->tx_pending_queue) <= local->remote_rw) {
+		struct sk_buff *pdu, *pending_pdu;
+
+		pdu = skb_dequeue(&llcp_sock->tx_queue);
+		if (pdu == NULL)
+			break;
+
+		/* Update N(S)/N(R) */
+		nfc_llcp_set_nrns(llcp_sock, pdu);
+
+		pending_pdu = skb_clone(pdu, GFP_KERNEL);
+
+		skb_queue_tail(&local->tx_queue, pdu);
+		skb_queue_tail(&llcp_sock->tx_pending_queue, pending_pdu);
+	}
+
+	release_sock(sk);
+	nfc_llcp_sock_put(llcp_sock);
+}
+
+static void nfc_llcp_recv_disc(struct nfc_llcp_local *local,
+				struct sk_buff *skb)
+{
+	struct nfc_llcp_sock *llcp_sock;
+	struct sock *sk;
+	u8 dsap, ssap;
+
+	dsap = nfc_llcp_dsap(skb);
+	ssap = nfc_llcp_ssap(skb);
+
+	llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
+	if (llcp_sock == NULL) {
+		nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);
+		return;
+	}
+
+	sk = &llcp_sock->sk;
+	lock_sock(sk);
+	if (sk->sk_state == LLCP_CLOSED) {
+		release_sock(sk);
+		nfc_llcp_sock_put(llcp_sock);
+	}
+
+
+	if (sk->sk_state == LLCP_CONNECTED) {
+		nfc_put_device(local->dev);
+		sk->sk_state = LLCP_CLOSED;
+		sk->sk_state_change(sk);
+	}
+
+	nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_DISC);
+
+	release_sock(sk);
+	nfc_llcp_sock_put(llcp_sock);
+}
+
+static void nfc_llcp_recv_cc(struct nfc_llcp_local *local,
+				struct sk_buff *skb)
+{
+	struct nfc_llcp_sock *llcp_sock;
+	u8 dsap, ssap;
+
+
+	dsap = nfc_llcp_dsap(skb);
+	ssap = nfc_llcp_ssap(skb);
+
+	llcp_sock = nfc_llcp_sock_get(local, dsap, ssap);
+
+	if (llcp_sock == NULL)
+		llcp_sock = nfc_llcp_sock_get(local, dsap, LLCP_SAP_SDP);
+
+	if (llcp_sock == NULL) {
+		pr_err("Invalid CC\n");
+		nfc_llcp_send_dm(local, dsap, ssap, LLCP_DM_NOCONN);
+
+		return;
+	}
+
+	llcp_sock->dsap = ssap;
+
+	nfc_llcp_parse_tlv(local, &skb->data[LLCP_HEADER_SIZE],
+				skb->len - LLCP_HEADER_SIZE);
+
+	nfc_llcp_sock_put(llcp_sock);
+}
+
+static void nfc_llcp_rx_work(struct work_struct *work)
+{
+	struct nfc_llcp_local *local = container_of(work, struct nfc_llcp_local,
+								rx_work);
+	u8 dsap, ssap, ptype;
+	struct sk_buff *skb;
+
+	skb = local->rx_pending;
+	if (skb == NULL) {
+		pr_debug("No pending SKB\n");
+		return;
+	}
+
+	ptype = nfc_llcp_ptype(skb);
+	dsap = nfc_llcp_dsap(skb);
+	ssap = nfc_llcp_ssap(skb);
+
+	pr_debug("ptype 0x%x dsap 0x%x ssap 0x%x\n", ptype, dsap, ssap);
+
+	switch (ptype) {
+	case LLCP_PDU_SYMM:
+		pr_debug("SYMM\n");
+		break;
+
+	case LLCP_PDU_CONNECT:
+		pr_debug("CONNECT\n");
+		nfc_llcp_recv_connect(local, skb);
+		break;
+
+	case LLCP_PDU_DISC:
+		pr_debug("DISC\n");
+		nfc_llcp_recv_disc(local, skb);
+		break;
+
+	case LLCP_PDU_CC:
+		pr_debug("CC\n");
+		nfc_llcp_recv_cc(local, skb);
+		break;
+
+	case LLCP_PDU_I:
+	case LLCP_PDU_RR:
+		pr_debug("I frame\n");
+		nfc_llcp_recv_hdlc(local, skb);
+		break;
+
+	}
+
+	queue_work(local->tx_wq, &local->tx_work);
+	kfree_skb(local->rx_pending);
+	local->rx_pending = NULL;
+
+	return;
+}
+
+void nfc_llcp_recv(void *data, struct sk_buff *skb, int err)
+{
+	struct nfc_llcp_local *local = (struct nfc_llcp_local *) data;
+
+	pr_debug("Received an LLCP PDU\n");
+	if (err < 0) {
+		pr_err("err %d", err);
+		return;
+	}
+
+	local->rx_pending = skb_get(skb);
+	del_timer(&local->link_timer);
+	queue_work(local->rx_wq, &local->rx_work);
+
+	return;
+}
+
+void nfc_llcp_mac_is_down(struct nfc_dev *dev)
+{
+	struct nfc_llcp_local *local;
+
+	local = nfc_llcp_find_local(dev);
+	if (local == NULL)
+		return;
+
+	/* Close and purge all existing sockets */
+	nfc_llcp_socket_release(local);
+}
+
+void nfc_llcp_mac_is_up(struct nfc_dev *dev, u32 target_idx,
+			u8 comm_mode, u8 rf_mode)
+{
+	struct nfc_llcp_local *local;
+
+	pr_debug("rf mode %d\n", rf_mode);
+
+	local = nfc_llcp_find_local(dev);
+	if (local == NULL)
+		return;
+
+	local->target_idx = target_idx;
+	local->comm_mode = comm_mode;
+	local->rf_mode = rf_mode;
+
+	if (rf_mode == NFC_RF_INITIATOR) {
+		pr_debug("Queueing Tx work\n");
+
+		queue_work(local->tx_wq, &local->tx_work);
+	} else {
+		mod_timer(&local->link_timer,
+			jiffies + msecs_to_jiffies(local->remote_lto));
+	}
+}
+
+int nfc_llcp_register_device(struct nfc_dev *ndev)
+{
+	struct device *dev = &ndev->dev;
+	struct nfc_llcp_local *local;
+	char name[32];
+	int err;
+
+	local = kzalloc(sizeof(struct nfc_llcp_local), GFP_KERNEL);
+	if (local == NULL)
+		return -ENOMEM;
+
+	local->dev = ndev;
+	INIT_LIST_HEAD(&local->list);
+	mutex_init(&local->sdp_lock);
+	mutex_init(&local->socket_lock);
+	init_timer(&local->link_timer);
+	local->link_timer.data = (unsigned long) local;
+	local->link_timer.function = nfc_llcp_symm_timer;
+
+	skb_queue_head_init(&local->tx_queue);
+	INIT_WORK(&local->tx_work, nfc_llcp_tx_work);
+	snprintf(name, sizeof(name), "%s_llcp_tx_wq", dev_name(dev));
+	local->tx_wq = alloc_workqueue(name,
+			WQ_NON_REENTRANT | WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
+	if (local->tx_wq == NULL) {
+		err = -ENOMEM;
+		goto err_local;
+	}
+
+	local->rx_pending = NULL;
+	INIT_WORK(&local->rx_work, nfc_llcp_rx_work);
+	snprintf(name, sizeof(name), "%s_llcp_rx_wq", dev_name(dev));
+	local->rx_wq = alloc_workqueue(name,
+			WQ_NON_REENTRANT | WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
+	if (local->rx_wq == NULL) {
+		err = -ENOMEM;
+		goto err_tx_wq;
+	}
+
+	INIT_WORK(&local->timeout_work, nfc_llcp_timeout_work);
+	snprintf(name, sizeof(name), "%s_llcp_timeout_wq", dev_name(dev));
+	local->timeout_wq = alloc_workqueue(name,
+			WQ_NON_REENTRANT | WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
+	if (local->timeout_wq == NULL) {
+		err = -ENOMEM;
+		goto err_rx_wq;
+	}
+
+	nfc_llcp_build_gb(local);
+
+	local->remote_miu = LLCP_DEFAULT_MIU;
+	local->remote_lto = LLCP_DEFAULT_LTO;
+	local->remote_rw = LLCP_DEFAULT_RW;
+
+	list_add(&llcp_devices, &local->list);
+
+	return 0;
+
+err_rx_wq:
+	destroy_workqueue(local->rx_wq);
+
+err_tx_wq:
+	destroy_workqueue(local->tx_wq);
+
+err_local:
+	kfree(local);
+
+	return 0;
+}
+
+void nfc_llcp_unregister_device(struct nfc_dev *dev)
+{
+	struct nfc_llcp_local *local = nfc_llcp_find_local(dev);
+
+	if (local == NULL) {
+		pr_debug("No such device\n");
+		return;
+	}
+
+	list_del(&local->list);
+	nfc_llcp_socket_release(local);
+	del_timer_sync(&local->link_timer);
+	skb_queue_purge(&local->tx_queue);
+	destroy_workqueue(local->tx_wq);
+	destroy_workqueue(local->rx_wq);
+	kfree(local->rx_pending);
+	kfree(local);
+}
+
+int __init nfc_llcp_init(void)
+{
+	INIT_LIST_HEAD(&llcp_devices);
+
+	return nfc_llcp_sock_init();
+}
+
+void nfc_llcp_exit(void)
+{
+	nfc_llcp_sock_exit();
+}