/*
   * Copyright (C) 2011 Instituto Nokia de Tecnologia
   *
   * Authors:
   *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
   *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
   *
   * 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) KBUILD_MODNAME ": %s: " fmt, __func__

  #include <net/tcp_states.h>
  #include <linux/nfc.h>

  #include <linux/export.h>

  
  #include "nfc.h"

  static struct nfc_sock_list raw_sk_list = {
  	.lock = __RW_LOCK_UNLOCKED(raw_sk_list.lock)
  };

  static void nfc_sock_link(struct nfc_sock_list *l, struct sock *sk)

  {
  	write_lock(&l->lock);
  	sk_add_node(sk, &l->head);
  	write_unlock(&l->lock);
  }

  static void nfc_sock_unlink(struct nfc_sock_list *l, struct sock *sk)

  {
  	write_lock(&l->lock);
  	sk_del_node_init(sk);
  	write_unlock(&l->lock);
  }

  static void rawsock_write_queue_purge(struct sock *sk)
  {

  	pr_debug("sk=%p
  ", sk);

  
  	spin_lock_bh(&sk->sk_write_queue.lock);
  	__skb_queue_purge(&sk->sk_write_queue);
  	nfc_rawsock(sk)->tx_work_scheduled = false;
  	spin_unlock_bh(&sk->sk_write_queue.lock);
  }
  
  static void rawsock_report_error(struct sock *sk, int err)
  {

  	pr_debug("sk=%p err=%d
  ", sk, err);

  
  	sk->sk_shutdown = SHUTDOWN_MASK;
  	sk->sk_err = -err;
  	sk->sk_error_report(sk);
  
  	rawsock_write_queue_purge(sk);
  }
  
  static int rawsock_release(struct socket *sock)
  {
  	struct sock *sk = sock->sk;

  	pr_debug("sock=%p sk=%p
  ", sock, sk);
  
  	if (!sk)
  		return 0;

  	if (sock->type == SOCK_RAW)
  		nfc_sock_unlink(&raw_sk_list, sk);

  	sock_orphan(sk);
  	sock_put(sk);
  
  	return 0;
  }
  
  static int rawsock_connect(struct socket *sock, struct sockaddr *_addr,

  			   int len, int flags)

  {
  	struct sock *sk = sock->sk;
  	struct sockaddr_nfc *addr = (struct sockaddr_nfc *)_addr;
  	struct nfc_dev *dev;
  	int rc = 0;

  	pr_debug("sock=%p sk=%p flags=%d
  ", sock, sk, flags);

  
  	if (!addr || len < sizeof(struct sockaddr_nfc) ||

  	    addr->sa_family != AF_NFC)

  		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 (sock->state == SS_CONNECTED) {
  		rc = -EISCONN;
  		goto error;
  	}
  
  	dev = nfc_get_device(addr->dev_idx);
  	if (!dev) {
  		rc = -ENODEV;
  		goto error;
  	}

  	if (addr->target_idx > dev->target_next_idx - 1 ||
  	    addr->target_idx < dev->target_next_idx - dev->n_targets) {

  		rc = -EINVAL;
  		goto error;
  	}

  	rc = nfc_activate_target(dev, addr->target_idx, addr->nfc_protocol);
  	if (rc)
  		goto put_dev;
  
  	nfc_rawsock(sk)->dev = dev;
  	nfc_rawsock(sk)->target_idx = addr->target_idx;
  	sock->state = SS_CONNECTED;
  	sk->sk_state = TCP_ESTABLISHED;
  	sk->sk_state_change(sk);
  
  	release_sock(sk);
  	return 0;
  
  put_dev:
  	nfc_put_device(dev);
  error:
  	release_sock(sk);
  	return rc;
  }
  
  static int rawsock_add_header(struct sk_buff *skb)
  {

  	*skb_push(skb, NFC_HEADER_SIZE) = 0;

  
  	return 0;
  }
  
  static void rawsock_data_exchange_complete(void *context, struct sk_buff *skb,

  					   int err)

  {
  	struct sock *sk = (struct sock *) context;
  
  	BUG_ON(in_irq());

  	pr_debug("sk=%p err=%d
  ", sk, err);

  
  	if (err)
  		goto error;
  
  	err = rawsock_add_header(skb);
  	if (err)

  		goto error_skb;

  
  	err = sock_queue_rcv_skb(sk, skb);
  	if (err)

  		goto error_skb;

  
  	spin_lock_bh(&sk->sk_write_queue.lock);
  	if (!skb_queue_empty(&sk->sk_write_queue))
  		schedule_work(&nfc_rawsock(sk)->tx_work);
  	else
  		nfc_rawsock(sk)->tx_work_scheduled = false;
  	spin_unlock_bh(&sk->sk_write_queue.lock);
  
  	sock_put(sk);
  	return;

  error_skb:
  	kfree_skb(skb);

  error:
  	rawsock_report_error(sk, err);
  	sock_put(sk);
  }
  
  static void rawsock_tx_work(struct work_struct *work)
  {
  	struct sock *sk = to_rawsock_sk(work);
  	struct nfc_dev *dev = nfc_rawsock(sk)->dev;
  	u32 target_idx = nfc_rawsock(sk)->target_idx;
  	struct sk_buff *skb;
  	int rc;

  	pr_debug("sk=%p target_idx=%u
  ", sk, target_idx);

  
  	if (sk->sk_shutdown & SEND_SHUTDOWN) {
  		rawsock_write_queue_purge(sk);
  		return;
  	}
  
  	skb = skb_dequeue(&sk->sk_write_queue);
  
  	sock_hold(sk);
  	rc = nfc_data_exchange(dev, target_idx, skb,

  			       rawsock_data_exchange_complete, sk);

  	if (rc) {
  		rawsock_report_error(sk, rc);
  		sock_put(sk);
  	}
  }
  
  static int rawsock_sendmsg(struct kiocb *iocb, struct socket *sock,

  			   struct msghdr *msg, size_t len)

  {
  	struct sock *sk = sock->sk;

  	struct nfc_dev *dev = nfc_rawsock(sk)->dev;

  	struct sk_buff *skb;
  	int rc;

  	pr_debug("sock=%p sk=%p len=%zu
  ", sock, sk, len);

  
  	if (msg->msg_namelen)
  		return -EOPNOTSUPP;
  
  	if (sock->state != SS_CONNECTED)
  		return -ENOTCONN;

  	skb = nfc_alloc_send_skb(dev, sk, msg->msg_flags, len, &rc);
  	if (skb == NULL)

  		return rc;

  	rc = memcpy_from_msg(skb_put(skb, len), msg, len);

  	if (rc < 0) {
  		kfree_skb(skb);
  		return rc;
  	}
  
  	spin_lock_bh(&sk->sk_write_queue.lock);
  	__skb_queue_tail(&sk->sk_write_queue, skb);
  	if (!nfc_rawsock(sk)->tx_work_scheduled) {
  		schedule_work(&nfc_rawsock(sk)->tx_work);
  		nfc_rawsock(sk)->tx_work_scheduled = true;
  	}
  	spin_unlock_bh(&sk->sk_write_queue.lock);
  
  	return len;
  }
  
  static int rawsock_recvmsg(struct kiocb *iocb, struct socket *sock,

  			   struct msghdr *msg, size_t len, int flags)

  {
  	int noblock = flags & MSG_DONTWAIT;
  	struct sock *sk = sock->sk;
  	struct sk_buff *skb;
  	int copied;
  	int rc;

  	pr_debug("sock=%p sk=%p len=%zu flags=%d
  ", sock, sk, len, flags);

  
  	skb = skb_recv_datagram(sk, flags, noblock, &rc);
  	if (!skb)
  		return rc;

  	copied = skb->len;
  	if (len < copied) {
  		msg->msg_flags |= MSG_TRUNC;
  		copied = len;
  	}

  	rc = skb_copy_datagram_msg(skb, 0, msg, copied);

  
  	skb_free_datagram(sk, skb);
  
  	return rc ? : copied;
  }

  static const struct proto_ops rawsock_ops = {
  	.family         = PF_NFC,
  	.owner          = THIS_MODULE,
  	.release        = rawsock_release,
  	.bind           = sock_no_bind,
  	.connect        = rawsock_connect,
  	.socketpair     = sock_no_socketpair,
  	.accept         = sock_no_accept,
  	.getname        = sock_no_getname,
  	.poll           = datagram_poll,
  	.ioctl          = sock_no_ioctl,
  	.listen         = sock_no_listen,
  	.shutdown       = sock_no_shutdown,
  	.setsockopt     = sock_no_setsockopt,
  	.getsockopt     = sock_no_getsockopt,
  	.sendmsg        = rawsock_sendmsg,
  	.recvmsg        = rawsock_recvmsg,
  	.mmap           = sock_no_mmap,
  };

  static const struct proto_ops rawsock_raw_ops = {
  	.family         = PF_NFC,
  	.owner          = THIS_MODULE,
  	.release        = rawsock_release,
  	.bind           = sock_no_bind,
  	.connect        = sock_no_connect,
  	.socketpair     = sock_no_socketpair,
  	.accept         = sock_no_accept,
  	.getname        = sock_no_getname,
  	.poll           = datagram_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        = rawsock_recvmsg,
  	.mmap           = sock_no_mmap,
  };

  static void rawsock_destruct(struct sock *sk)
  {

  	pr_debug("sk=%p
  ", sk);

  
  	if (sk->sk_state == TCP_ESTABLISHED) {
  		nfc_deactivate_target(nfc_rawsock(sk)->dev,

  				      nfc_rawsock(sk)->target_idx);

  		nfc_put_device(nfc_rawsock(sk)->dev);
  	}
  
  	skb_queue_purge(&sk->sk_receive_queue);
  
  	if (!sock_flag(sk, SOCK_DEAD)) {

  		pr_err("Freeing alive NFC raw socket %p
  ", sk);

  		return;
  	}
  }
  
  static int rawsock_create(struct net *net, struct socket *sock,

  			  const struct nfc_protocol *nfc_proto)

  {
  	struct sock *sk;

  	pr_debug("sock=%p
  ", sock);

  	if ((sock->type != SOCK_SEQPACKET) && (sock->type != SOCK_RAW))

  		return -ESOCKTNOSUPPORT;

  	if (sock->type == SOCK_RAW)
  		sock->ops = &rawsock_raw_ops;
  	else
  		sock->ops = &rawsock_ops;

  	sk = sk_alloc(net, PF_NFC, GFP_ATOMIC, nfc_proto->proto);

  	if (!sk)
  		return -ENOMEM;
  
  	sock_init_data(sock, sk);
  	sk->sk_protocol = nfc_proto->id;
  	sk->sk_destruct = rawsock_destruct;
  	sock->state = SS_UNCONNECTED;

  	if (sock->type == SOCK_RAW)
  		nfc_sock_link(&raw_sk_list, sk);
  	else {
  		INIT_WORK(&nfc_rawsock(sk)->tx_work, rawsock_tx_work);
  		nfc_rawsock(sk)->tx_work_scheduled = false;
  	}

  
  	return 0;
  }

  void nfc_send_to_raw_sock(struct nfc_dev *dev, struct sk_buff *skb,
  			  u8 payload_type, u8 direction)
  {
  	struct sk_buff *skb_copy = NULL, *nskb;
  	struct sock *sk;
  	u8 *data;
  
  	read_lock(&raw_sk_list.lock);
  
  	sk_for_each(sk, &raw_sk_list.head) {
  		if (!skb_copy) {

  			skb_copy = __pskb_copy_fclone(skb, NFC_RAW_HEADER_SIZE,
  						      GFP_ATOMIC, true);

  			if (!skb_copy)
  				continue;
  
  			data = skb_push(skb_copy, NFC_RAW_HEADER_SIZE);
  
  			data[0] = dev ? dev->idx : 0xFF;
  			data[1] = direction & 0x01;
  			data[1] |= (payload_type << 1);
  		}
  
  		nskb = skb_clone(skb_copy, GFP_ATOMIC);
  		if (!nskb)
  			continue;
  
  		if (sock_queue_rcv_skb(sk, nskb))
  			kfree_skb(nskb);
  	}
  
  	read_unlock(&raw_sk_list.lock);
  
  	kfree_skb(skb_copy);
  }
  EXPORT_SYMBOL(nfc_send_to_raw_sock);

  static struct proto rawsock_proto = {
  	.name     = "NFC_RAW",
  	.owner    = THIS_MODULE,
  	.obj_size = sizeof(struct nfc_rawsock),
  };
  
  static const struct nfc_protocol rawsock_nfc_proto = {
  	.id	  = NFC_SOCKPROTO_RAW,
  	.proto    = &rawsock_proto,
  	.owner    = THIS_MODULE,
  	.create   = rawsock_create
  };
  
  int __init rawsock_init(void)
  {
  	int rc;
  
  	rc = nfc_proto_register(&rawsock_nfc_proto);
  
  	return rc;
  }
  
  void rawsock_exit(void)
  {
  	nfc_proto_unregister(&rawsock_nfc_proto);
  }