/*
   * 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 <linux/sched/signal.h>

  #include "nfc.h"

  #include "llcp.h"

  static int sock_wait_state(struct sock *sk, int state, unsigned long timeo)
  {
  	DECLARE_WAITQUEUE(wait, current);
  	int err = 0;
  
  	pr_debug("sk %p", sk);
  
  	add_wait_queue(sk_sleep(sk), &wait);
  	set_current_state(TASK_INTERRUPTIBLE);
  
  	while (sk->sk_state != state) {
  		if (!timeo) {
  			err = -EINPROGRESS;
  			break;
  		}
  
  		if (signal_pending(current)) {
  			err = sock_intr_errno(timeo);
  			break;
  		}
  
  		release_sock(sk);
  		timeo = schedule_timeout(timeo);
  		lock_sock(sk);
  		set_current_state(TASK_INTERRUPTIBLE);
  
  		err = sock_error(sk);
  		if (err)
  			break;
  	}
  
  	__set_current_state(TASK_RUNNING);
  	remove_wait_queue(sk_sleep(sk), &wait);
  	return err;
  }

  static struct proto llcp_sock_proto = {
  	.name     = "NFC_LLCP",
  	.owner    = THIS_MODULE,
  	.obj_size = sizeof(struct nfc_llcp_sock),
  };
  
  static int llcp_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
  {
  	struct sock *sk = sock->sk;
  	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
  	struct nfc_llcp_local *local;
  	struct nfc_dev *dev;
  	struct sockaddr_nfc_llcp llcp_addr;
  	int len, ret = 0;

  	if (!addr || alen < offsetofend(struct sockaddr, sa_family) ||
  	    addr->sa_family != AF_NFC)

  		return -EINVAL;

  	pr_debug("sk %p addr %p family %d
  ", sk, addr, addr->sa_family);

  	memset(&llcp_addr, 0, sizeof(llcp_addr));
  	len = min_t(unsigned int, sizeof(llcp_addr), alen);
  	memcpy(&llcp_addr, addr, len);
  
  	/* This is going to be a listening socket, dsap must be 0 */
  	if (llcp_addr.dsap != 0)
  		return -EINVAL;
  
  	lock_sock(sk);
  
  	if (sk->sk_state != LLCP_CLOSED) {
  		ret = -EBADFD;
  		goto error;
  	}
  
  	dev = nfc_get_device(llcp_addr.dev_idx);
  	if (dev == NULL) {
  		ret = -ENODEV;
  		goto error;
  	}
  
  	local = nfc_llcp_find_local(dev);
  	if (local == NULL) {
  		ret = -ENODEV;
  		goto put_dev;
  	}
  
  	llcp_sock->dev = dev;

  	llcp_sock->local = nfc_llcp_local_get(local);

  	llcp_sock->nfc_protocol = llcp_addr.nfc_protocol;
  	llcp_sock->service_name_len = min_t(unsigned int,

  					    llcp_addr.service_name_len,
  					    NFC_LLCP_MAX_SERVICE_NAME);

  	llcp_sock->service_name = kmemdup(llcp_addr.service_name,

  					  llcp_sock->service_name_len,
  					  GFP_KERNEL);

  
  	llcp_sock->ssap = nfc_llcp_get_sdp_ssap(local, llcp_sock);

  	if (llcp_sock->ssap == LLCP_SAP_MAX) {
  		ret = -EADDRINUSE;

  		goto put_dev;

  	}

  	llcp_sock->reserved_ssap = llcp_sock->ssap;

  	nfc_llcp_sock_link(&local->sockets, sk);

  
  	pr_debug("Socket bound to SAP %d
  ", llcp_sock->ssap);
  
  	sk->sk_state = LLCP_BOUND;
  
  put_dev:
  	nfc_put_device(dev);
  
  error:
  	release_sock(sk);
  	return ret;
  }

  static int llcp_raw_sock_bind(struct socket *sock, struct sockaddr *addr,
  			      int alen)
  {
  	struct sock *sk = sock->sk;
  	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
  	struct nfc_llcp_local *local;
  	struct nfc_dev *dev;
  	struct sockaddr_nfc_llcp llcp_addr;
  	int len, ret = 0;

  	if (!addr || alen < offsetofend(struct sockaddr, sa_family) ||
  	    addr->sa_family != AF_NFC)

  		return -EINVAL;
  
  	pr_debug("sk %p addr %p family %d
  ", sk, addr, addr->sa_family);
  
  	memset(&llcp_addr, 0, sizeof(llcp_addr));
  	len = min_t(unsigned int, sizeof(llcp_addr), alen);
  	memcpy(&llcp_addr, addr, len);
  
  	lock_sock(sk);
  
  	if (sk->sk_state != LLCP_CLOSED) {
  		ret = -EBADFD;
  		goto error;
  	}
  
  	dev = nfc_get_device(llcp_addr.dev_idx);
  	if (dev == NULL) {
  		ret = -ENODEV;
  		goto error;
  	}
  
  	local = nfc_llcp_find_local(dev);
  	if (local == NULL) {
  		ret = -ENODEV;
  		goto put_dev;
  	}
  
  	llcp_sock->dev = dev;
  	llcp_sock->local = nfc_llcp_local_get(local);
  	llcp_sock->nfc_protocol = llcp_addr.nfc_protocol;
  
  	nfc_llcp_sock_link(&local->raw_sockets, sk);
  
  	sk->sk_state = LLCP_BOUND;
  
  put_dev:
  	nfc_put_device(dev);
  
  error:
  	release_sock(sk);
  	return ret;
  }

  static int llcp_sock_listen(struct socket *sock, int backlog)
  {
  	struct sock *sk = sock->sk;
  	int ret = 0;
  
  	pr_debug("sk %p backlog %d
  ", sk, backlog);
  
  	lock_sock(sk);

  	if ((sock->type != SOCK_SEQPACKET && sock->type != SOCK_STREAM) ||
  	    sk->sk_state != LLCP_BOUND) {

  		ret = -EBADFD;
  		goto error;
  	}
  
  	sk->sk_max_ack_backlog = backlog;
  	sk->sk_ack_backlog = 0;
  
  	pr_debug("Socket listening
  ");
  	sk->sk_state = LLCP_LISTEN;
  
  error:
  	release_sock(sk);
  
  	return ret;
  }

  static int nfc_llcp_setsockopt(struct socket *sock, int level, int optname,
  			       char __user *optval, unsigned int optlen)
  {
  	struct sock *sk = sock->sk;
  	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
  	u32 opt;
  	int err = 0;
  
  	pr_debug("%p optname %d
  ", sk, optname);
  
  	if (level != SOL_NFC)
  		return -ENOPROTOOPT;
  
  	lock_sock(sk);
  
  	switch (optname) {
  	case NFC_LLCP_RW:
  		if (sk->sk_state == LLCP_CONNECTED ||
  		    sk->sk_state == LLCP_BOUND ||
  		    sk->sk_state == LLCP_LISTEN) {
  			err = -EINVAL;
  			break;
  		}
  
  		if (get_user(opt, (u32 __user *) optval)) {
  			err = -EFAULT;
  			break;
  		}
  
  		if (opt > LLCP_MAX_RW) {
  			err = -EINVAL;
  			break;
  		}
  
  		llcp_sock->rw = (u8) opt;
  
  		break;
  
  	case NFC_LLCP_MIUX:
  		if (sk->sk_state == LLCP_CONNECTED ||
  		    sk->sk_state == LLCP_BOUND ||
  		    sk->sk_state == LLCP_LISTEN) {
  			err = -EINVAL;
  			break;
  		}
  
  		if (get_user(opt, (u32 __user *) optval)) {
  			err = -EFAULT;
  			break;
  		}
  
  		if (opt > LLCP_MAX_MIUX) {
  			err = -EINVAL;
  			break;
  		}

  		llcp_sock->miux = cpu_to_be16((u16) opt);

  
  		break;
  
  	default:
  		err = -ENOPROTOOPT;
  		break;
  	}
  
  	release_sock(sk);

  	pr_debug("%p rw %d miux %d
  ", llcp_sock,
  		 llcp_sock->rw, llcp_sock->miux);

  	return err;
  }
  
  static int nfc_llcp_getsockopt(struct socket *sock, int level, int optname,
  			       char __user *optval, int __user *optlen)
  {

  	struct nfc_llcp_local *local;

  	struct sock *sk = sock->sk;
  	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
  	int len, err = 0;

  	u16 miux, remote_miu;

  	u8 rw;

  
  	pr_debug("%p optname %d
  ", sk, optname);
  
  	if (level != SOL_NFC)
  		return -ENOPROTOOPT;
  
  	if (get_user(len, optlen))
  		return -EFAULT;

  	local = llcp_sock->local;
  	if (!local)
  		return -ENODEV;

  	len = min_t(u32, len, sizeof(u32));
  
  	lock_sock(sk);
  
  	switch (optname) {
  	case NFC_LLCP_RW:

  		rw = llcp_sock->rw > LLCP_MAX_RW ? local->rw : llcp_sock->rw;
  		if (put_user(rw, (u32 __user *) optval))

  			err = -EFAULT;
  
  		break;
  
  	case NFC_LLCP_MIUX:

  		miux = be16_to_cpu(llcp_sock->miux) > LLCP_MAX_MIUX ?
  			be16_to_cpu(local->miux) : be16_to_cpu(llcp_sock->miux);
  
  		if (put_user(miux, (u32 __user *) optval))

  			err = -EFAULT;
  
  		break;

  	case NFC_LLCP_REMOTE_MIU:
  		remote_miu = llcp_sock->remote_miu > LLCP_MAX_MIU ?
  				local->remote_miu : llcp_sock->remote_miu;
  
  		if (put_user(remote_miu, (u32 __user *) optval))
  			err = -EFAULT;
  
  		break;
  
  	case NFC_LLCP_REMOTE_LTO:
  		if (put_user(local->remote_lto / 10, (u32 __user *) optval))
  			err = -EFAULT;
  
  		break;
  
  	case NFC_LLCP_REMOTE_RW:
  		if (put_user(llcp_sock->remote_rw, (u32 __user *) optval))

  			err = -EFAULT;
  
  		break;
  
  	default:
  		err = -ENOPROTOOPT;
  		break;
  	}
  
  	release_sock(sk);
  
  	if (put_user(len, optlen))
  		return -EFAULT;
  
  	return err;
  }

  void nfc_llcp_accept_unlink(struct sock *sk)
  {
  	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
  
  	pr_debug("state %d
  ", sk->sk_state);
  
  	list_del_init(&llcp_sock->accept_queue);
  	sk_acceptq_removed(llcp_sock->parent);
  	llcp_sock->parent = NULL;
  
  	sock_put(sk);
  }
  
  void nfc_llcp_accept_enqueue(struct sock *parent, struct sock *sk)
  {
  	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
  	struct nfc_llcp_sock *llcp_sock_parent = nfc_llcp_sock(parent);
  
  	/* Lock will be free from unlink */
  	sock_hold(sk);
  
  	list_add_tail(&llcp_sock->accept_queue,

  		      &llcp_sock_parent->accept_queue);

  	llcp_sock->parent = parent;
  	sk_acceptq_added(parent);
  }
  
  struct sock *nfc_llcp_accept_dequeue(struct sock *parent,

  				     struct socket *newsock)

  {
  	struct nfc_llcp_sock *lsk, *n, *llcp_parent;
  	struct sock *sk;
  
  	llcp_parent = nfc_llcp_sock(parent);
  
  	list_for_each_entry_safe(lsk, n, &llcp_parent->accept_queue,

  				 accept_queue) {

  		sk = &lsk->sk;
  		lock_sock(sk);
  
  		if (sk->sk_state == LLCP_CLOSED) {
  			release_sock(sk);
  			nfc_llcp_accept_unlink(sk);
  			continue;
  		}
  
  		if (sk->sk_state == LLCP_CONNECTED || !newsock) {

  			list_del_init(&lsk->accept_queue);
  			sock_put(sk);

  			if (newsock)
  				sock_graft(sk, newsock);
  
  			release_sock(sk);
  
  			pr_debug("Returning sk state %d
  ", sk->sk_state);

  			sk_acceptq_removed(parent);

  			return sk;
  		}
  
  		release_sock(sk);
  	}
  
  	return NULL;
  }
  
  static int llcp_sock_accept(struct socket *sock, struct socket *newsock,

  			    int flags, bool kern)

  {
  	DECLARE_WAITQUEUE(wait, current);
  	struct sock *sk = sock->sk, *new_sk;
  	long timeo;
  	int ret = 0;
  
  	pr_debug("parent %p
  ", sk);
  
  	lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
  
  	if (sk->sk_state != LLCP_LISTEN) {
  		ret = -EBADFD;
  		goto error;
  	}
  
  	timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
  
  	/* Wait for an incoming connection. */
  	add_wait_queue_exclusive(sk_sleep(sk), &wait);
  	while (!(new_sk = nfc_llcp_accept_dequeue(sk, newsock))) {
  		set_current_state(TASK_INTERRUPTIBLE);
  
  		if (!timeo) {
  			ret = -EAGAIN;
  			break;
  		}
  
  		if (signal_pending(current)) {
  			ret = sock_intr_errno(timeo);
  			break;
  		}
  
  		release_sock(sk);
  		timeo = schedule_timeout(timeo);
  		lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
  	}
  	__set_current_state(TASK_RUNNING);
  	remove_wait_queue(sk_sleep(sk), &wait);
  
  	if (ret)
  		goto error;
  
  	newsock->state = SS_CONNECTED;
  
  	pr_debug("new socket %p
  ", new_sk);
  
  error:
  	release_sock(sk);
  
  	return ret;
  }

  static int llcp_sock_getname(struct socket *sock, struct sockaddr *uaddr,

  			     int *len, int peer)
  {

  	struct sock *sk = sock->sk;
  	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);

  	DECLARE_SOCKADDR(struct sockaddr_nfc_llcp *, llcp_addr, uaddr);

  	if (llcp_sock == NULL || llcp_sock->dev == NULL)
  		return -EBADFD;

  	pr_debug("%p %d %d %d
  ", sk, llcp_sock->target_idx,
  		 llcp_sock->dsap, llcp_sock->ssap);

  	memset(llcp_addr, 0, sizeof(*llcp_addr));

  	*len = sizeof(struct sockaddr_nfc_llcp);

  	lock_sock(sk);
  	if (!llcp_sock->dev) {
  		release_sock(sk);
  		return -EBADFD;
  	}

  	llcp_addr->sa_family = AF_NFC;

  	llcp_addr->dev_idx = llcp_sock->dev->idx;

  	llcp_addr->target_idx = llcp_sock->target_idx;

  	llcp_addr->nfc_protocol = llcp_sock->nfc_protocol;

  	llcp_addr->dsap = llcp_sock->dsap;
  	llcp_addr->ssap = llcp_sock->ssap;
  	llcp_addr->service_name_len = llcp_sock->service_name_len;
  	memcpy(llcp_addr->service_name, llcp_sock->service_name,

  	       llcp_addr->service_name_len);

  	release_sock(sk);

  
  	return 0;
  }
  
  static inline unsigned int llcp_accept_poll(struct sock *parent)
  {

  	struct nfc_llcp_sock *llcp_sock, *parent_sock;

  	struct sock *sk;
  
  	parent_sock = nfc_llcp_sock(parent);

  	list_for_each_entry(llcp_sock, &parent_sock->accept_queue,
  			    accept_queue) {

  		sk = &llcp_sock->sk;
  
  		if (sk->sk_state == LLCP_CONNECTED)
  			return POLLIN | POLLRDNORM;
  	}
  
  	return 0;
  }
  
  static unsigned int llcp_sock_poll(struct file *file, struct socket *sock,

  				   poll_table *wait)

  {
  	struct sock *sk = sock->sk;
  	unsigned int mask = 0;
  
  	pr_debug("%p
  ", sk);
  
  	sock_poll_wait(file, sk_sleep(sk), wait);
  
  	if (sk->sk_state == LLCP_LISTEN)
  		return llcp_accept_poll(sk);
  
  	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))

  		mask |= POLLERR |

  			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);

  
  	if (!skb_queue_empty(&sk->sk_receive_queue))

  		mask |= POLLIN | POLLRDNORM;

  
  	if (sk->sk_state == LLCP_CLOSED)
  		mask |= POLLHUP;

  	if (sk->sk_shutdown & RCV_SHUTDOWN)
  		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
  
  	if (sk->sk_shutdown == SHUTDOWN_MASK)
  		mask |= POLLHUP;

  	if (sock_writeable(sk) && sk->sk_state == LLCP_CONNECTED)

  		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
  	else

  		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);

  
  	pr_debug("mask 0x%x
  ", mask);

  	return mask;
  }
  
  static int llcp_sock_release(struct socket *sock)
  {
  	struct sock *sk = sock->sk;
  	struct nfc_llcp_local *local;
  	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);

  	int err = 0;

  
  	if (!sk)
  		return 0;
  
  	pr_debug("%p
  ", sk);
  
  	local = llcp_sock->local;

  	if (local == NULL) {
  		err = -ENODEV;
  		goto out;
  	}

  	lock_sock(sk);
  
  	/* Send a DISC */
  	if (sk->sk_state == LLCP_CONNECTED)

  		nfc_llcp_send_disconnect(llcp_sock);

  
  	if (sk->sk_state == LLCP_LISTEN) {
  		struct nfc_llcp_sock *lsk, *n;
  		struct sock *accept_sk;
  
  		list_for_each_entry_safe(lsk, n, &llcp_sock->accept_queue,

  					 accept_queue) {

  			accept_sk = &lsk->sk;
  			lock_sock(accept_sk);

  			nfc_llcp_send_disconnect(lsk);

  			nfc_llcp_accept_unlink(accept_sk);
  
  			release_sock(accept_sk);

  		}
  	}

  	if (llcp_sock->reserved_ssap < LLCP_SAP_MAX)
  		nfc_llcp_put_ssap(llcp_sock->local, llcp_sock->ssap);

  	release_sock(sk);

  	/* Keep this sock alive and therefore do not remove it from the sockets
  	 * list until the DISC PDU has been actually sent. Otherwise we would
  	 * reply with DM PDUs before sending the DISC one.
  	 */
  	if (sk->sk_state == LLCP_DISCONNECTING)
  		return err;

  	if (sock->type == SOCK_RAW)
  		nfc_llcp_sock_unlink(&local->raw_sockets, sk);
  	else
  		nfc_llcp_sock_unlink(&local->sockets, sk);

  out:

  	sock_orphan(sk);
  	sock_put(sk);

  	return err;

  }
  
  static int llcp_sock_connect(struct socket *sock, struct sockaddr *_addr,

  			     int len, int flags)

  {
  	struct sock *sk = sock->sk;
  	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
  	struct sockaddr_nfc_llcp *addr = (struct sockaddr_nfc_llcp *)_addr;
  	struct nfc_dev *dev;
  	struct nfc_llcp_local *local;
  	int ret = 0;
  
  	pr_debug("sock %p sk %p flags 0x%x
  ", sock, sk, flags);

  	if (!addr || len < sizeof(*addr) || addr->sa_family != AF_NFC)

  		return -EINVAL;

  	if (addr->service_name_len == 0 && addr->dsap == 0)

  		return -EINVAL;

  
  	pr_debug("addr dev_idx=%u target_idx=%u protocol=%u
  ", addr->dev_idx,

  		 addr->target_idx, addr->nfc_protocol);

  
  	lock_sock(sk);
  
  	if (sk->sk_state == LLCP_CONNECTED) {
  		ret = -EISCONN;
  		goto error;
  	}
  
  	dev = nfc_get_device(addr->dev_idx);
  	if (dev == NULL) {
  		ret = -ENODEV;
  		goto error;
  	}
  
  	local = nfc_llcp_find_local(dev);
  	if (local == NULL) {
  		ret = -ENODEV;
  		goto put_dev;
  	}
  
  	device_lock(&dev->dev);
  	if (dev->dep_link_up == false) {
  		ret = -ENOLINK;
  		device_unlock(&dev->dev);
  		goto put_dev;
  	}
  	device_unlock(&dev->dev);
  
  	if (local->rf_mode == NFC_RF_INITIATOR &&

  	    addr->target_idx != local->target_idx) {

  		ret = -ENOLINK;
  		goto put_dev;
  	}
  
  	llcp_sock->dev = dev;

  	llcp_sock->local = nfc_llcp_local_get(local);

  	llcp_sock->ssap = nfc_llcp_get_local_ssap(local);
  	if (llcp_sock->ssap == LLCP_SAP_MAX) {
  		ret = -ENOMEM;
  		goto put_dev;
  	}

  
  	llcp_sock->reserved_ssap = llcp_sock->ssap;

  	if (addr->service_name_len == 0)
  		llcp_sock->dsap = addr->dsap;
  	else
  		llcp_sock->dsap = LLCP_SAP_SDP;
  	llcp_sock->nfc_protocol = addr->nfc_protocol;
  	llcp_sock->service_name_len = min_t(unsigned int,

  					    addr->service_name_len,
  					    NFC_LLCP_MAX_SERVICE_NAME);

  	llcp_sock->service_name = kmemdup(addr->service_name,

  					  llcp_sock->service_name_len,
  					  GFP_KERNEL);

  	nfc_llcp_sock_link(&local->connecting_sockets, sk);

  
  	ret = nfc_llcp_send_connect(llcp_sock);
  	if (ret)

  		goto sock_unlink;

  	sk->sk_state = LLCP_CONNECTING;

  	ret = sock_wait_state(sk, LLCP_CONNECTED,
  			      sock_sndtimeo(sk, flags & O_NONBLOCK));

  	if (ret && ret != -EINPROGRESS)

  		goto sock_unlink;

  
  	release_sock(sk);

  	return ret;

  sock_unlink:
  	nfc_llcp_put_ssap(local, llcp_sock->ssap);
  
  	nfc_llcp_sock_unlink(&local->connecting_sockets, sk);

  put_dev:
  	nfc_put_device(dev);
  
  error:
  	release_sock(sk);
  	return ret;
  }

  static int llcp_sock_sendmsg(struct socket *sock, struct msghdr *msg,
  			     size_t len)

  {
  	struct sock *sk = sock->sk;
  	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
  	int ret;
  
  	pr_debug("sock %p sk %p", sock, sk);
  
  	ret = sock_error(sk);
  	if (ret)
  		return ret;
  
  	if (msg->msg_flags & MSG_OOB)
  		return -EOPNOTSUPP;
  
  	lock_sock(sk);

  	if (sk->sk_type == SOCK_DGRAM) {

  		DECLARE_SOCKADDR(struct sockaddr_nfc_llcp *, addr,
  				 msg->msg_name);

  
  		if (msg->msg_namelen < sizeof(*addr)) {
  			release_sock(sk);

  			return -EINVAL;
  		}
  
  		release_sock(sk);
  
  		return nfc_llcp_send_ui_frame(llcp_sock, addr->dsap, addr->ssap,
  					      msg, len);
  	}

  	if (sk->sk_state != LLCP_CONNECTED) {
  		release_sock(sk);
  		return -ENOTCONN;
  	}
  
  	release_sock(sk);
  
  	return nfc_llcp_send_i_frame(llcp_sock, msg, len);
  }

  static int llcp_sock_recvmsg(struct socket *sock, struct msghdr *msg,
  			     size_t len, int flags)

  {
  	int noblock = flags & MSG_DONTWAIT;
  	struct sock *sk = sock->sk;
  	unsigned int copied, rlen;
  	struct sk_buff *skb, *cskb;
  	int err = 0;
  
  	pr_debug("%p %zu
  ", sk, len);
  
  	lock_sock(sk);
  
  	if (sk->sk_state == LLCP_CLOSED &&

  	    skb_queue_empty(&sk->sk_receive_queue)) {

  		release_sock(sk);
  		return 0;
  	}
  
  	release_sock(sk);
  
  	if (flags & (MSG_OOB))
  		return -EOPNOTSUPP;
  
  	skb = skb_recv_datagram(sk, flags, noblock, &err);
  	if (!skb) {
  		pr_err("Recv datagram failed state %d %d %d",

  		       sk->sk_state, err, sock_error(sk));

  
  		if (sk->sk_shutdown & RCV_SHUTDOWN)
  			return 0;
  
  		return err;
  	}

  	rlen = skb->len;		/* real length of skb */

  	copied = min_t(unsigned int, rlen, len);
  
  	cskb = skb;

  	if (skb_copy_datagram_msg(cskb, 0, msg, copied)) {

  		if (!(flags & MSG_PEEK))
  			skb_queue_head(&sk->sk_receive_queue, skb);
  		return -EFAULT;
  	}

  	sock_recv_timestamp(msg, sk, skb);

  	if (sk->sk_type == SOCK_DGRAM && msg->msg_name) {
  		struct nfc_llcp_ui_cb *ui_cb = nfc_llcp_ui_skb_cb(skb);

  		DECLARE_SOCKADDR(struct sockaddr_nfc_llcp *, sockaddr,
  				 msg->msg_name);

  		msg->msg_namelen = sizeof(struct sockaddr_nfc_llcp);

  		pr_debug("Datagram socket %d %d
  ", ui_cb->dsap, ui_cb->ssap);

  		memset(sockaddr, 0, sizeof(*sockaddr));

  		sockaddr->sa_family = AF_NFC;
  		sockaddr->nfc_protocol = NFC_PROTO_NFC_DEP;
  		sockaddr->dsap = ui_cb->dsap;
  		sockaddr->ssap = ui_cb->ssap;

  	}

  	/* Mark read part of skb as used */
  	if (!(flags & MSG_PEEK)) {
  
  		/* SOCK_STREAM: re-queue skb if it contains unreceived data */

  		if (sk->sk_type == SOCK_STREAM ||
  		    sk->sk_type == SOCK_DGRAM ||
  		    sk->sk_type == SOCK_RAW) {

  			skb_pull(skb, copied);
  			if (skb->len) {
  				skb_queue_head(&sk->sk_receive_queue, skb);
  				goto done;
  			}
  		}
  
  		kfree_skb(skb);
  	}
  
  	/* XXX Queue backlogged skbs */
  
  done:
  	/* SOCK_SEQPACKET: return real length if MSG_TRUNC is set */
  	if (sk->sk_type == SOCK_SEQPACKET && (flags & MSG_TRUNC))
  		copied = rlen;
  
  	return copied;
  }
  
  static const struct proto_ops llcp_sock_ops = {
  	.family         = PF_NFC,
  	.owner          = THIS_MODULE,
  	.bind           = llcp_sock_bind,
  	.connect        = llcp_sock_connect,
  	.release        = llcp_sock_release,
  	.socketpair     = sock_no_socketpair,
  	.accept         = llcp_sock_accept,
  	.getname        = llcp_sock_getname,
  	.poll           = llcp_sock_poll,
  	.ioctl          = sock_no_ioctl,
  	.listen         = llcp_sock_listen,
  	.shutdown       = sock_no_shutdown,

  	.setsockopt     = nfc_llcp_setsockopt,
  	.getsockopt     = nfc_llcp_getsockopt,

  	.sendmsg        = llcp_sock_sendmsg,

  	.recvmsg        = llcp_sock_recvmsg,
  	.mmap           = sock_no_mmap,
  };

  static const struct proto_ops llcp_rawsock_ops = {
  	.family         = PF_NFC,
  	.owner          = THIS_MODULE,
  	.bind           = llcp_raw_sock_bind,
  	.connect        = sock_no_connect,
  	.release        = llcp_sock_release,
  	.socketpair     = sock_no_socketpair,
  	.accept         = sock_no_accept,
  	.getname        = llcp_sock_getname,
  	.poll           = llcp_sock_poll,
  	.ioctl          = sock_no_ioctl,
  	.listen         = sock_no_listen,
  	.shutdown       = sock_no_shutdown,
  	.setsockopt     = sock_no_setsockopt,
  	.getsockopt     = sock_no_getsockopt,
  	.sendmsg        = sock_no_sendmsg,
  	.recvmsg        = llcp_sock_recvmsg,
  	.mmap           = sock_no_mmap,
  };

  static void llcp_sock_destruct(struct sock *sk)
  {
  	struct nfc_llcp_sock *llcp_sock = nfc_llcp_sock(sk);
  
  	pr_debug("%p
  ", sk);
  
  	if (sk->sk_state == LLCP_CONNECTED)
  		nfc_put_device(llcp_sock->dev);
  
  	skb_queue_purge(&sk->sk_receive_queue);
  
  	nfc_llcp_sock_free(llcp_sock);
  
  	if (!sock_flag(sk, SOCK_DEAD)) {
  		pr_err("Freeing alive NFC LLCP socket %p
  ", sk);
  		return;
  	}
  }

  struct sock *nfc_llcp_sock_alloc(struct socket *sock, int type, gfp_t gfp, int kern)

  {
  	struct sock *sk;
  	struct nfc_llcp_sock *llcp_sock;

  	sk = sk_alloc(&init_net, PF_NFC, gfp, &llcp_sock_proto, kern);

  	if (!sk)
  		return NULL;
  
  	llcp_sock = nfc_llcp_sock(sk);
  
  	sock_init_data(sock, sk);
  	sk->sk_state = LLCP_CLOSED;
  	sk->sk_protocol = NFC_SOCKPROTO_LLCP;
  	sk->sk_type = type;
  	sk->sk_destruct = llcp_sock_destruct;
  
  	llcp_sock->ssap = 0;
  	llcp_sock->dsap = LLCP_SAP_SDP;

  	llcp_sock->rw = LLCP_MAX_RW + 1;

  	llcp_sock->miux = cpu_to_be16(LLCP_MAX_MIUX + 1);

  	llcp_sock->send_n = llcp_sock->send_ack_n = 0;
  	llcp_sock->recv_n = llcp_sock->recv_ack_n = 0;
  	llcp_sock->remote_ready = 1;

  	llcp_sock->reserved_ssap = LLCP_SAP_MAX;

  	nfc_llcp_socket_remote_param_init(llcp_sock);

  	skb_queue_head_init(&llcp_sock->tx_queue);
  	skb_queue_head_init(&llcp_sock->tx_pending_queue);

  	INIT_LIST_HEAD(&llcp_sock->accept_queue);
  
  	if (sock != NULL)
  		sock->state = SS_UNCONNECTED;
  
  	return sk;
  }
  
  void nfc_llcp_sock_free(struct nfc_llcp_sock *sock)
  {
  	kfree(sock->service_name);
  
  	skb_queue_purge(&sock->tx_queue);
  	skb_queue_purge(&sock->tx_pending_queue);

  
  	list_del_init(&sock->accept_queue);

  	sock->parent = NULL;

  
  	nfc_llcp_local_put(sock->local);

  }
  
  static int llcp_sock_create(struct net *net, struct socket *sock,

  			    const struct nfc_protocol *nfc_proto, int kern)

  {
  	struct sock *sk;
  
  	pr_debug("%p
  ", sock);

  	if (sock->type != SOCK_STREAM &&
  	    sock->type != SOCK_DGRAM &&
  	    sock->type != SOCK_RAW)

  		return -ESOCKTNOSUPPORT;

  	if (sock->type == SOCK_RAW)
  		sock->ops = &llcp_rawsock_ops;
  	else
  		sock->ops = &llcp_sock_ops;

  	sk = nfc_llcp_sock_alloc(sock, sock->type, GFP_ATOMIC, kern);

  	if (sk == NULL)
  		return -ENOMEM;
  
  	return 0;
  }
  
  static const struct nfc_protocol llcp_nfc_proto = {
  	.id	  = NFC_SOCKPROTO_LLCP,
  	.proto    = &llcp_sock_proto,
  	.owner    = THIS_MODULE,
  	.create   = llcp_sock_create
  };
  
  int __init nfc_llcp_sock_init(void)
  {
  	return nfc_proto_register(&llcp_nfc_proto);
  }
  
  void nfc_llcp_sock_exit(void)
  {
  	nfc_proto_unregister(&llcp_nfc_proto);
  }