/*

 * 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\n", 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\n", 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\n", 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\n", 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\n",

		 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)

{

	*(u8 *)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\n", 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\n", 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 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\n", 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 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\n", 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\n", sk);

	if (sk->sk_state == TCP_ESTABLISHED) {

		nfc_deactivate_target(nfc_rawsock(sk)->dev,

				      nfc_rawsock(sk)->target_idx,

				      NFC_TARGET_MODE_IDLE);

		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\n", sk);

		return;

	}

}

static int rawsock_create(struct net *net, struct socket *sock,

			  const struct nfc_protocol *nfc_proto, int kern)

{

	struct sock *sk;

	pr_debug("sock=%p\n", 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, kern);

	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);

}