net/bluetooth/sco.c

/*
   BlueZ - Bluetooth protocol stack for Linux
   Copyright (C) 2000-2001 Qualcomm Incorporated

   Written 2000,2001 by Maxim Krasnyansky <maxk@qualcomm.com>

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License version 2 as
   published by the Free Software Foundation;

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
   IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
   CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

   ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
   COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
   SOFTWARE IS DISCLAIMED.
*/

/* Bluetooth SCO sockets. */

#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <net/bluetooth/sco.h>

static bool disable_esco;

static const struct proto_ops sco_sock_ops;

static struct bt_sock_list sco_sk_list = {
	.lock = __RW_LOCK_UNLOCKED(sco_sk_list.lock)
};

static void __sco_chan_add(struct sco_conn *conn, struct sock *sk, struct sock *parent);
static void sco_chan_del(struct sock *sk, int err);

static void sco_sock_close(struct sock *sk);
static void sco_sock_kill(struct sock *sk);

/* ---- SCO timers ---- */
static void sco_sock_timeout(unsigned long arg)
{
	struct sock *sk = (struct sock *) arg;

	BT_DBG("sock %p state %d", sk, sk->sk_state);

	bh_lock_sock(sk);
	sk->sk_err = ETIMEDOUT;
	sk->sk_state_change(sk);
	bh_unlock_sock(sk);

	sco_sock_kill(sk);
	sock_put(sk);
}

static void sco_sock_set_timer(struct sock *sk, long timeout)
{
	BT_DBG("sock %p state %d timeout %ld", sk, sk->sk_state, timeout);
	sk_reset_timer(sk, &sk->sk_timer, jiffies + timeout);
}

static void sco_sock_clear_timer(struct sock *sk)
{
	BT_DBG("sock %p state %d", sk, sk->sk_state);
	sk_stop_timer(sk, &sk->sk_timer);
}

/* ---- SCO connections ---- */
static struct sco_conn *sco_conn_add(struct hci_conn *hcon)
{
	struct hci_dev *hdev = hcon->hdev;
	struct sco_conn *conn = hcon->sco_data;

	if (conn)
		return conn;

	conn = kzalloc(sizeof(struct sco_conn), GFP_KERNEL);
	if (!conn)
		return NULL;

	spin_lock_init(&conn->lock);

	hcon->sco_data = conn;
	conn->hcon = hcon;

	conn->src = &hdev->bdaddr;
	conn->dst = &hcon->dst;

	if (hdev->sco_mtu > 0)
		conn->mtu = hdev->sco_mtu;
	else
		conn->mtu = 60;

	BT_DBG("hcon %p conn %p", hcon, conn);

	return conn;
}

static struct sock *sco_chan_get(struct sco_conn *conn)
{
	struct sock *sk = NULL;
	sco_conn_lock(conn);
	sk = conn->sk;
	sco_conn_unlock(conn);
	return sk;
}

static int sco_conn_del(struct hci_conn *hcon, int err)
{
	struct sco_conn *conn = hcon->sco_data;
	struct sock *sk;

	if (!conn)
		return 0;

	BT_DBG("hcon %p conn %p, err %d", hcon, conn, err);

	/* Kill socket */
	sk = sco_chan_get(conn);
	if (sk) {
		bh_lock_sock(sk);
		sco_sock_clear_timer(sk);
		sco_chan_del(sk, err);
		bh_unlock_sock(sk);
		sco_sock_kill(sk);
	}

	hcon->sco_data = NULL;
	kfree(conn);
	return 0;
}

static int sco_chan_add(struct sco_conn *conn, struct sock *sk,
			struct sock *parent)
{
	int err = 0;

	sco_conn_lock(conn);
	if (conn->sk)
		err = -EBUSY;
	else
		__sco_chan_add(conn, sk, parent);

	sco_conn_unlock(conn);
	return err;
}

static int sco_connect(struct sock *sk)
{
	bdaddr_t *src = &bt_sk(sk)->src;
	bdaddr_t *dst = &bt_sk(sk)->dst;
	struct sco_conn *conn;
	struct hci_conn *hcon;
	struct hci_dev  *hdev;
	int err, type;

	BT_DBG("%pMR -> %pMR", src, dst);

	hdev = hci_get_route(dst, src);
	if (!hdev)
		return -EHOSTUNREACH;

	hci_dev_lock(hdev);

	if (lmp_esco_capable(hdev) && !disable_esco)
		type = ESCO_LINK;
	else
		type = SCO_LINK;

	hcon = hci_connect_sco(hdev, type, dst);
	if (IS_ERR(hcon)) {
		err = PTR_ERR(hcon);
		goto done;
	}

	conn = sco_conn_add(hcon);
	if (!conn) {
		hci_conn_drop(hcon);
		err = -ENOMEM;
		goto done;
	}

	/* Update source addr of the socket */
	bacpy(src, conn->src);

	err = sco_chan_add(conn, sk, NULL);
	if (err)
		goto done;

	if (hcon->state == BT_CONNECTED) {
		sco_sock_clear_timer(sk);
		sk->sk_state = BT_CONNECTED;
	} else {
		sk->sk_state = BT_CONNECT;
		sco_sock_set_timer(sk, sk->sk_sndtimeo);
	}

done:
	hci_dev_unlock(hdev);
	hci_dev_put(hdev);
	return err;
}

static int sco_send_frame(struct sock *sk, struct msghdr *msg, int len)
{
	struct sco_conn *conn = sco_pi(sk)->conn;
	struct sk_buff *skb;
	int err;

	/* Check outgoing MTU */
	if (len > conn->mtu)
		return -EINVAL;

	BT_DBG("sk %p len %d", sk, len);

	skb = bt_skb_send_alloc(sk, len, msg->msg_flags & MSG_DONTWAIT, &err);
	if (!skb)
		return err;

	if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
		kfree_skb(skb);
		return -EFAULT;
	}

	hci_send_sco(conn->hcon, skb);

	return len;
}

static void sco_recv_frame(struct sco_conn *conn, struct sk_buff *skb)
{
	struct sock *sk = sco_chan_get(conn);

	if (!sk)
		goto drop;

	BT_DBG("sk %p len %d", sk, skb->len);

	if (sk->sk_state != BT_CONNECTED)
		goto drop;

	if (!sock_queue_rcv_skb(sk, skb))
		return;

drop:
	kfree_skb(skb);
}

/* -------- Socket interface ---------- */
static struct sock *__sco_get_sock_listen_by_addr(bdaddr_t *ba)
{
	struct sock *sk;

	sk_for_each(sk, &sco_sk_list.head) {
		if (sk->sk_state != BT_LISTEN)
			continue;

		if (!bacmp(&bt_sk(sk)->src, ba))
			return sk;
	}

	return NULL;
}

/* Find socket listening on source bdaddr.
 * Returns closest match.
 */
static struct sock *sco_get_sock_listen(bdaddr_t *src)
{
	struct sock *sk = NULL, *sk1 = NULL;

	read_lock(&sco_sk_list.lock);

	sk_for_each(sk, &sco_sk_list.head) {
		if (sk->sk_state != BT_LISTEN)
			continue;

		/* Exact match. */
		if (!bacmp(&bt_sk(sk)->src, src))
			break;

		/* Closest match */
		if (!bacmp(&bt_sk(sk)->src, BDADDR_ANY))
			sk1 = sk;
	}

	read_unlock(&sco_sk_list.lock);

	return sk ? sk : sk1;
}

static void sco_sock_destruct(struct sock *sk)
{
	BT_DBG("sk %p", sk);

	skb_queue_purge(&sk->sk_receive_queue);
	skb_queue_purge(&sk->sk_write_queue);
}

static void sco_sock_cleanup_listen(struct sock *parent)
{
	struct sock *sk;

	BT_DBG("parent %p", parent);

	/* Close not yet accepted channels */
	while ((sk = bt_accept_dequeue(parent, NULL))) {
		sco_sock_close(sk);
		sco_sock_kill(sk);
	}

	parent->sk_state  = BT_CLOSED;
	sock_set_flag(parent, SOCK_ZAPPED);
}

/* Kill socket (only if zapped and orphan)
 * Must be called on unlocked socket.
 */
static void sco_sock_kill(struct sock *sk)
{
	if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket)
		return;

	BT_DBG("sk %p state %d", sk, sk->sk_state);

	/* Kill poor orphan */
	bt_sock_unlink(&sco_sk_list, sk);
	sock_set_flag(sk, SOCK_DEAD);
	sock_put(sk);
}

static void __sco_sock_close(struct sock *sk)
{
	BT_DBG("sk %p state %d socket %p", sk, sk->sk_state, sk->sk_socket);

	switch (sk->sk_state) {
	case BT_LISTEN:
		sco_sock_cleanup_listen(sk);
		break;

	case BT_CONNECTED:
	case BT_CONFIG:
		if (sco_pi(sk)->conn->hcon) {
			sk->sk_state = BT_DISCONN;
			sco_sock_set_timer(sk, SCO_DISCONN_TIMEOUT);
			hci_conn_drop(sco_pi(sk)->conn->hcon);
			sco_pi(sk)->conn->hcon = NULL;
		} else
			sco_chan_del(sk, ECONNRESET);
		break;

	case BT_CONNECT2:
	case BT_CONNECT:
	case BT_DISCONN:
		sco_chan_del(sk, ECONNRESET);
		break;

	default:
		sock_set_flag(sk, SOCK_ZAPPED);
		break;
	}
}

/* Must be called on unlocked socket. */
static void sco_sock_close(struct sock *sk)
{
	sco_sock_clear_timer(sk);
	lock_sock(sk);
	__sco_sock_close(sk);
	release_sock(sk);
	sco_sock_kill(sk);
}

static void sco_sock_init(struct sock *sk, struct sock *parent)
{
	BT_DBG("sk %p", sk);

	if (parent) {
		sk->sk_type = parent->sk_type;
		bt_sk(sk)->flags = bt_sk(parent)->flags;
		security_sk_clone(parent, sk);
	}
}

static struct proto sco_proto = {
	.name		= "SCO",
	.owner		= THIS_MODULE,
	.obj_size	= sizeof(struct sco_pinfo)
};

static struct sock *sco_sock_alloc(struct net *net, struct socket *sock, int proto, gfp_t prio)
{
	struct sock *sk;

	sk = sk_alloc(net, PF_BLUETOOTH, prio, &sco_proto);
	if (!sk)
		return NULL;

	sock_init_data(sock, sk);
	INIT_LIST_HEAD(&bt_sk(sk)->accept_q);

	sk->sk_destruct = sco_sock_destruct;
	sk->sk_sndtimeo = SCO_CONN_TIMEOUT;

	sock_reset_flag(sk, SOCK_ZAPPED);

	sk->sk_protocol = proto;
	sk->sk_state    = BT_OPEN;

	sco_pi(sk)->setting = BT_VOICE_CVSD_16BIT;

	setup_timer(&sk->sk_timer, sco_sock_timeout, (unsigned long)sk);

	bt_sock_link(&sco_sk_list, sk);
	return sk;
}

static int sco_sock_create(struct net *net, struct socket *sock, int protocol,
			   int kern)
{
	struct sock *sk;

	BT_DBG("sock %p", sock);

	sock->state = SS_UNCONNECTED;

	if (sock->type != SOCK_SEQPACKET)
		return -ESOCKTNOSUPPORT;

	sock->ops = &sco_sock_ops;

	sk = sco_sock_alloc(net, sock, protocol, GFP_ATOMIC);
	if (!sk)
		return -ENOMEM;

	sco_sock_init(sk, NULL);
	return 0;
}

static int sco_sock_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
{
	struct sockaddr_sco *sa = (struct sockaddr_sco *) addr;
	struct sock *sk = sock->sk;
	int err = 0;

	BT_DBG("sk %p %pMR", sk, &sa->sco_bdaddr);

	if (!addr || addr->sa_family != AF_BLUETOOTH)
		return -EINVAL;

	lock_sock(sk);

	if (sk->sk_state != BT_OPEN) {
		err = -EBADFD;
		goto done;
	}

	if (sk->sk_type != SOCK_SEQPACKET) {
		err = -EINVAL;
		goto done;
	}

	bacpy(&bt_sk(sk)->src, &sa->sco_bdaddr);

	sk->sk_state = BT_BOUND;

done:
	release_sock(sk);
	return err;
}

static int sco_sock_connect(struct socket *sock, struct sockaddr *addr, int alen, int flags)
{
	struct sockaddr_sco *sa = (struct sockaddr_sco *) addr;
	struct sock *sk = sock->sk;
	int err;

	BT_DBG("sk %p", sk);

	if (alen < sizeof(struct sockaddr_sco) ||
	    addr->sa_family != AF_BLUETOOTH)
		return -EINVAL;

	if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND)
		return -EBADFD;

	if (sk->sk_type != SOCK_SEQPACKET)
		return -EINVAL;

	lock_sock(sk);

	/* Set destination address and psm */
	bacpy(&bt_sk(sk)->dst, &sa->sco_bdaddr);

	err = sco_connect(sk);
	if (err)
		goto done;

	err = bt_sock_wait_state(sk, BT_CONNECTED,
				 sock_sndtimeo(sk, flags & O_NONBLOCK));

done:
	release_sock(sk);
	return err;
}

static int sco_sock_listen(struct socket *sock, int backlog)
{
	struct sock *sk = sock->sk;
	bdaddr_t *src = &bt_sk(sk)->src;
	int err = 0;

	BT_DBG("sk %p backlog %d", sk, backlog);

	lock_sock(sk);

	if (sk->sk_state != BT_BOUND) {
		err = -EBADFD;
		goto done;
	}

	if (sk->sk_type != SOCK_SEQPACKET) {
		err = -EINVAL;
		goto done;
	}

	write_lock(&sco_sk_list.lock);

	if (__sco_get_sock_listen_by_addr(src)) {
		err = -EADDRINUSE;
		goto unlock;
	}

	sk->sk_max_ack_backlog = backlog;
	sk->sk_ack_backlog = 0;

	sk->sk_state = BT_LISTEN;

unlock:
	write_unlock(&sco_sk_list.lock);

done:
	release_sock(sk);
	return err;
}

static int sco_sock_accept(struct socket *sock, struct socket *newsock, int flags)
{
	DECLARE_WAITQUEUE(wait, current);
	struct sock *sk = sock->sk, *ch;
	long timeo;
	int err = 0;

	lock_sock(sk);

	timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);

	BT_DBG("sk %p timeo %ld", sk, timeo);

	/* Wait for an incoming connection. (wake-one). */
	add_wait_queue_exclusive(sk_sleep(sk), &wait);
	while (1) {
		set_current_state(TASK_INTERRUPTIBLE);

		if (sk->sk_state != BT_LISTEN) {
			err = -EBADFD;
			break;
		}

		ch = bt_accept_dequeue(sk, newsock);
		if (ch)
			break;

		if (!timeo) {
			err = -EAGAIN;
			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_RUNNING);
	remove_wait_queue(sk_sleep(sk), &wait);

	if (err)
		goto done;

	newsock->state = SS_CONNECTED;

	BT_DBG("new socket %p", ch);

done:
	release_sock(sk);
	return err;
}

static int sco_sock_getname(struct socket *sock, struct sockaddr *addr, int *len, int peer)
{
	struct sockaddr_sco *sa = (struct sockaddr_sco *) addr;
	struct sock *sk = sock->sk;

	BT_DBG("sock %p, sk %p", sock, sk);

	addr->sa_family = AF_BLUETOOTH;
	*len = sizeof(struct sockaddr_sco);

	if (peer)
		bacpy(&sa->sco_bdaddr, &bt_sk(sk)->dst);
	else
		bacpy(&sa->sco_bdaddr, &bt_sk(sk)->src);

	return 0;
}

static int sco_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
			    struct msghdr *msg, size_t len)
{
	struct sock *sk = sock->sk;
	int err;

	BT_DBG("sock %p, sk %p", sock, sk);

	err = sock_error(sk);
	if (err)
		return err;

	if (msg->msg_flags & MSG_OOB)
		return -EOPNOTSUPP;

	lock_sock(sk);

	if (sk->sk_state == BT_CONNECTED)
		err = sco_send_frame(sk, msg, len);
	else
		err = -ENOTCONN;

	release_sock(sk);
	return err;
}

static void sco_conn_defer_accept(struct hci_conn *conn)
{
	struct hci_dev *hdev = conn->hdev;

	BT_DBG("conn %p", conn);

	conn->state = BT_CONFIG;

	if (!lmp_esco_capable(hdev)) {
		struct hci_cp_accept_conn_req cp;

		bacpy(&cp.bdaddr, &conn->dst);
		cp.role = 0x00; /* Ignored */

		hci_send_cmd(hdev, HCI_OP_ACCEPT_CONN_REQ, sizeof(cp), &cp);
	} else {
		struct hci_cp_accept_sync_conn_req cp;

		bacpy(&cp.bdaddr, &conn->dst);
		cp.pkt_type = cpu_to_le16(conn->pkt_type);

		cp.tx_bandwidth   = __constant_cpu_to_le32(0x00001f40);
		cp.rx_bandwidth   = __constant_cpu_to_le32(0x00001f40);
		cp.max_latency    = __constant_cpu_to_le16(0xffff);
		cp.content_format = cpu_to_le16(hdev->voice_setting);
		cp.retrans_effort = 0xff;

		hci_send_cmd(hdev, HCI_OP_ACCEPT_SYNC_CONN_REQ,
			     sizeof(cp), &cp);
	}
}

static int sco_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
			    struct msghdr *msg, size_t len, int flags)
{
	struct sock *sk = sock->sk;
	struct sco_pinfo *pi = sco_pi(sk);

	lock_sock(sk);

	if (sk->sk_state == BT_CONNECT2 &&
	    test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags)) {
		sco_conn_defer_accept(pi->conn->hcon);
		sk->sk_state = BT_CONFIG;
		msg->msg_namelen = 0;

		release_sock(sk);
		return 0;
	}

	release_sock(sk);

	return bt_sock_recvmsg(iocb, sock, msg, len, flags);
}

static int sco_sock_setsockopt(struct socket *sock, int level, int optname, char __user *optval, unsigned int optlen)
{
	struct sock *sk = sock->sk;
	int len, err = 0;
	struct bt_voice voice;
	u32 opt;

	BT_DBG("sk %p", sk);

	lock_sock(sk);

	switch (optname) {

	case BT_DEFER_SETUP:
		if (sk->sk_state != BT_BOUND && sk->sk_state != BT_LISTEN) {
			err = -EINVAL;
			break;
		}

		if (get_user(opt, (u32 __user *) optval)) {
			err = -EFAULT;
			break;
		}

		if (opt)
			set_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags);
		else
			clear_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags);
		break;

	case BT_VOICE:
		if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND &&
		    sk->sk_state != BT_CONNECT2) {
			err = -EINVAL;
			break;
		}

		voice.setting = sco_pi(sk)->setting;

		len = min_t(unsigned int, sizeof(voice), optlen);
		if (copy_from_user((char *) &voice, optval, len)) {
			err = -EFAULT;
			break;
		}

		/* Explicitly check for these values */
		if (voice.setting != BT_VOICE_TRANSPARENT &&
		    voice.setting != BT_VOICE_CVSD_16BIT) {
			err = -EINVAL;
			break;
		}

		sco_pi(sk)->setting = voice.setting;
		break;

	default:
		err = -ENOPROTOOPT;
		break;
	}

	release_sock(sk);
	return err;
}

static int sco_sock_getsockopt_old(struct socket *sock, int optname, char __user *optval, int __user *optlen)
{
	struct sock *sk = sock->sk;
	struct sco_options opts;
	struct sco_conninfo cinfo;
	int len, err = 0;

	BT_DBG("sk %p", sk);

	if (get_user(len, optlen))
		return -EFAULT;

	lock_sock(sk);

	switch (optname) {
	case SCO_OPTIONS:
		if (sk->sk_state != BT_CONNECTED &&
		    !(sk->sk_state == BT_CONNECT2 &&
		      test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags))) {
			err = -ENOTCONN;
			break;
		}

		opts.mtu = sco_pi(sk)->conn->mtu;

		BT_DBG("mtu %d", opts.mtu);

		len = min_t(unsigned int, len, sizeof(opts));
		if (copy_to_user(optval, (char *)&opts, len))
			err = -EFAULT;

		break;

	case SCO_CONNINFO:
		if (sk->sk_state != BT_CONNECTED &&
		    !(sk->sk_state == BT_CONNECT2 &&
		      test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags))) {
			err = -ENOTCONN;
			break;
		}

		memset(&cinfo, 0, sizeof(cinfo));
		cinfo.hci_handle = sco_pi(sk)->conn->hcon->handle;
		memcpy(cinfo.dev_class, sco_pi(sk)->conn->hcon->dev_class, 3);

		len = min_t(unsigned int, len, sizeof(cinfo));
		if (copy_to_user(optval, (char *)&cinfo, len))
			err = -EFAULT;

		break;

	default:
		err = -ENOPROTOOPT;
		break;
	}

	release_sock(sk);
	return err;
}

static int sco_sock_getsockopt(struct socket *sock, int level, int optname, char __user *optval, int __user *optlen)
{
	struct sock *sk = sock->sk;
	int len, err = 0;
	struct bt_voice voice;

	BT_DBG("sk %p", sk);

	if (level == SOL_SCO)
		return sco_sock_getsockopt_old(sock, optname, optval, optlen);

	if (get_user(len, optlen))
		return -EFAULT;

	lock_sock(sk);

	switch (optname) {

	case BT_DEFER_SETUP:
		if (sk->sk_state != BT_BOUND && sk->sk_state != BT_LISTEN) {
			err = -EINVAL;
			break;
		}

		if (put_user(test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags),
			     (u32 __user *) optval))
			err = -EFAULT;

		break;

	case BT_VOICE:
		voice.setting = sco_pi(sk)->setting;

		len = min_t(unsigned int, len, sizeof(voice));
		if (copy_to_user(optval, (char *)&voice, len))
			err = -EFAULT;

		break;

	default:
		err = -ENOPROTOOPT;
		break;
	}

	release_sock(sk);
	return err;
}

static int sco_sock_shutdown(struct socket *sock, int how)
{
	struct sock *sk = sock->sk;
	int err = 0;

	BT_DBG("sock %p, sk %p", sock, sk);

	if (!sk)
		return 0;

	lock_sock(sk);
	if (!sk->sk_shutdown) {
		sk->sk_shutdown = SHUTDOWN_MASK;
		sco_sock_clear_timer(sk);
		__sco_sock_close(sk);

		if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime)
			err = bt_sock_wait_state(sk, BT_CLOSED,
						 sk->sk_lingertime);
	}
	release_sock(sk);
	return err;
}

static int sco_sock_release(struct socket *sock)
{
	struct sock *sk = sock->sk;
	int err = 0;

	BT_DBG("sock %p, sk %p", sock, sk);

	if (!sk)
		return 0;

	sco_sock_close(sk);

	if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime) {
		lock_sock(sk);
		err = bt_sock_wait_state(sk, BT_CLOSED, sk->sk_lingertime);
		release_sock(sk);
	}

	sock_orphan(sk);
	sco_sock_kill(sk);
	return err;
}

static void __sco_chan_add(struct sco_conn *conn, struct sock *sk, struct sock *parent)
{
	BT_DBG("conn %p", conn);

	sco_pi(sk)->conn = conn;
	conn->sk = sk;

	if (parent)
		bt_accept_enqueue(parent, sk);
}

/* Delete channel.
 * Must be called on the locked socket. */
static void sco_chan_del(struct sock *sk, int err)
{
	struct sco_conn *conn;

	conn = sco_pi(sk)->conn;

	BT_DBG("sk %p, conn %p, err %d", sk, conn, err);

	if (conn) {
		sco_conn_lock(conn);
		conn->sk = NULL;
		sco_pi(sk)->conn = NULL;
		sco_conn_unlock(conn);

		if (conn->hcon)
			hci_conn_drop(conn->hcon);
	}

	sk->sk_state = BT_CLOSED;
	sk->sk_err   = err;
	sk->sk_state_change(sk);

	sock_set_flag(sk, SOCK_ZAPPED);
}

static void sco_conn_ready(struct sco_conn *conn)
{
	struct sock *parent;
	struct sock *sk = conn->sk;

	BT_DBG("conn %p", conn);

	if (sk) {
		sco_sock_clear_timer(sk);
		bh_lock_sock(sk);
		sk->sk_state = BT_CONNECTED;
		sk->sk_state_change(sk);
		bh_unlock_sock(sk);
	} else {
		sco_conn_lock(conn);

		parent = sco_get_sock_listen(conn->src);
		if (!parent) {
			sco_conn_unlock(conn);
			return;
		}

		bh_lock_sock(parent);

		sk = sco_sock_alloc(sock_net(parent), NULL,
				    BTPROTO_SCO, GFP_ATOMIC);
		if (!sk) {
			bh_unlock_sock(parent);
			sco_conn_unlock(conn);
			return;
		}

		sco_sock_init(sk, parent);

		bacpy(&bt_sk(sk)->src, conn->src);
		bacpy(&bt_sk(sk)->dst, conn->dst);

		hci_conn_hold(conn->hcon);
		__sco_chan_add(conn, sk, parent);

		if (test_bit(BT_SK_DEFER_SETUP, &bt_sk(parent)->flags))
			sk->sk_state = BT_CONNECT2;
		else
			sk->sk_state = BT_CONNECTED;

		/* Wake up parent */
		parent->sk_data_ready(parent, 1);

		bh_unlock_sock(parent);

		sco_conn_unlock(conn);
	}
}

/* ----- SCO interface with lower layer (HCI) ----- */
int sco_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, __u8 *flags)
{
	struct sock *sk;
	int lm = 0;

	BT_DBG("hdev %s, bdaddr %pMR", hdev->name, bdaddr);

	/* Find listening sockets */
	read_lock(&sco_sk_list.lock);
	sk_for_each(sk, &sco_sk_list.head) {
		if (sk->sk_state != BT_LISTEN)
			continue;

		if (!bacmp(&bt_sk(sk)->src, &hdev->bdaddr) ||
		    !bacmp(&bt_sk(sk)->src, BDADDR_ANY)) {
			lm |= HCI_LM_ACCEPT;

			if (test_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags))
				*flags |= HCI_PROTO_DEFER;
			break;
		}
	}
	read_unlock(&sco_sk_list.lock);

	return lm;
}

void sco_connect_cfm(struct hci_conn *hcon, __u8 status)
{
	BT_DBG("hcon %p bdaddr %pMR status %d", hcon, &hcon->dst, status);
	if (!status) {
		struct sco_conn *conn;

		conn = sco_conn_add(hcon);
		if (conn)
			sco_conn_ready(conn);
	} else
		sco_conn_del(hcon, bt_to_errno(status));
}

void sco_disconn_cfm(struct hci_conn *hcon, __u8 reason)
{
	BT_DBG("hcon %p reason %d", hcon, reason);

	sco_conn_del(hcon, bt_to_errno(reason));
}

int sco_recv_scodata(struct hci_conn *hcon, struct sk_buff *skb)
{
	struct sco_conn *conn = hcon->sco_data;

	if (!conn)
		goto drop;

	BT_DBG("conn %p len %d", conn, skb->len);

	if (skb->len) {
		sco_recv_frame(conn, skb);
		return 0;
	}

drop:
	kfree_skb(skb);
	return 0;
}

static int sco_debugfs_show(struct seq_file *f, void *p)
{
	struct sock *sk;

	read_lock(&sco_sk_list.lock);

	sk_for_each(sk, &sco_sk_list.head) {
		seq_printf(f, "%pMR %pMR %d\n", &bt_sk(sk)->src,
			   &bt_sk(sk)->dst, sk->sk_state);
	}

	read_unlock(&sco_sk_list.lock);

	return 0;
}

static int sco_debugfs_open(struct inode *inode, struct file *file)
{
	return single_open(file, sco_debugfs_show, inode->i_private);
}

static const struct file_operations sco_debugfs_fops = {
	.open		= sco_debugfs_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static struct dentry *sco_debugfs;

static const struct proto_ops sco_sock_ops = {
	.family		= PF_BLUETOOTH,
	.owner		= THIS_MODULE,
	.release	= sco_sock_release,
	.bind		= sco_sock_bind,
	.connect	= sco_sock_connect,
	.listen		= sco_sock_listen,
	.accept		= sco_sock_accept,
	.getname	= sco_sock_getname,
	.sendmsg	= sco_sock_sendmsg,
	.recvmsg	= sco_sock_recvmsg,
	.poll		= bt_sock_poll,
	.ioctl		= bt_sock_ioctl,
	.mmap		= sock_no_mmap,
	.socketpair	= sock_no_socketpair,
	.shutdown	= sco_sock_shutdown,
	.setsockopt	= sco_sock_setsockopt,
	.getsockopt	= sco_sock_getsockopt
};

static const struct net_proto_family sco_sock_family_ops = {
	.family	= PF_BLUETOOTH,
	.owner	= THIS_MODULE,
	.create	= sco_sock_create,
};

int __init sco_init(void)
{
	int err;

	err = proto_register(&sco_proto, 0);
	if (err < 0)
		return err;

	err = bt_sock_register(BTPROTO_SCO, &sco_sock_family_ops);
	if (err < 0) {
		BT_ERR("SCO socket registration failed");
		goto error;
	}

	err = bt_procfs_init(&init_net, "sco", &sco_sk_list, NULL);
	if (err < 0) {
		BT_ERR("Failed to create SCO proc file");
		bt_sock_unregister(BTPROTO_SCO);
		goto error;
	}

	if (bt_debugfs) {
		sco_debugfs = debugfs_create_file("sco", 0444, bt_debugfs,
						  NULL, &sco_debugfs_fops);
		if (!sco_debugfs)
			BT_ERR("Failed to create SCO debug file");
	}

	BT_INFO("SCO socket layer initialized");

	return 0;

error:
	proto_unregister(&sco_proto);
	return err;
}

void __exit sco_exit(void)
{
	bt_procfs_cleanup(&init_net, "sco");

	debugfs_remove(sco_debugfs);

	bt_sock_unregister(BTPROTO_SCO);

	proto_unregister(&sco_proto);
}

module_param(disable_esco, bool, 0644);
MODULE_PARM_DESC(disable_esco, "Disable eSCO connection creation");