net/bluetooth/l2cap_sock.c

/*
   BlueZ - Bluetooth protocol stack for Linux
   Copyright (C) 2000-2001 Qualcomm Incorporated
   Copyright (C) 2009-2010 Gustavo F. Padovan <gustavo@padovan.org>
   Copyright (C) 2010 Google Inc.

   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 L2CAP sockets. */

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <net/bluetooth/l2cap.h>
#include <net/bluetooth/smp.h>
#include <net/bluetooth/amp.h>

/* ---- L2CAP timers ---- */
static void l2cap_sock_timeout(unsigned long arg)
{
	struct sock *sk = (struct sock *) arg;
	int reason;

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

	bh_lock_sock(sk);

	if (sock_owned_by_user(sk)) {
		/* sk is owned by user. Try again later */
		l2cap_sock_set_timer(sk, HZ / 5);
		bh_unlock_sock(sk);
		sock_put(sk);
		return;
	}

	if (sk->sk_state == BT_CONNECTED || sk->sk_state == BT_CONFIG)
		reason = ECONNREFUSED;
	else if (sk->sk_state == BT_CONNECT &&
				l2cap_pi(sk)->sec_level != BT_SECURITY_SDP)
		reason = ECONNREFUSED;
	else
		reason = ETIMEDOUT;

	__l2cap_sock_close(sk, reason);

	bh_unlock_sock(sk);

	l2cap_sock_kill(sk);
	sock_put(sk);
}

void l2cap_sock_set_timer(struct sock *sk, long timeout)
{
	BT_DBG("sk %p state %d timeout %ld", sk, sk->sk_state, timeout);
	sk_reset_timer(sk, &sk->sk_timer, jiffies + timeout);
}

void l2cap_sock_clear_timer(struct sock *sk)
{
	BT_DBG("sock %p state %d", sk, sk->sk_state);
	sk_stop_timer(sk, &sk->sk_timer);
}

static struct sock *__l2cap_get_sock_by_addr(__le16 psm, bdaddr_t *src)
{
	struct sock *sk;
	struct hlist_node *node;
	sk_for_each(sk, node, &l2cap_sk_list.head)
		if (l2cap_pi(sk)->sport == psm && !bacmp(&bt_sk(sk)->src, src))
			goto found;
	sk = NULL;
found:
	return sk;
}

static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
{
	struct sock *sk = sock->sk;
	struct sockaddr_l2 la;
	int len, err = 0;

	BT_DBG("sk %p", sk);

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

	memset(&la, 0, sizeof(la));
	len = min_t(unsigned int, sizeof(la), alen);
	memcpy(&la, addr, len);

	if (la.l2_cid && la.l2_psm)
		return -EINVAL;

	lock_sock(sk);

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

	if (la.l2_psm) {
		__u16 psm = __le16_to_cpu(la.l2_psm);

		/* PSM must be odd and lsb of upper byte must be 0 */
		if ((psm & 0x0101) != 0x0001) {
			err = -EINVAL;
			goto done;
		}

		/* Restrict usage of well-known PSMs */
		if (psm < 0x1001 && !capable(CAP_NET_BIND_SERVICE)) {
			err = -EACCES;
			goto done;
		}
	}

	write_lock_bh(&l2cap_sk_list.lock);

	if (la.l2_psm && __l2cap_get_sock_by_addr(la.l2_psm, &la.l2_bdaddr)) {
		err = -EADDRINUSE;
	} else {
		/* Save source address */
		bacpy(&bt_sk(sk)->src, &la.l2_bdaddr);
		l2cap_pi(sk)->psm   = la.l2_psm;
		l2cap_pi(sk)->sport = la.l2_psm;
		sk->sk_state = BT_BOUND;

		if (__le16_to_cpu(la.l2_psm) == 0x0001 ||
					__le16_to_cpu(la.l2_psm) == 0x0003)
			l2cap_pi(sk)->sec_level = BT_SECURITY_SDP;
	}

	if (la.l2_cid)
		l2cap_pi(sk)->scid = la.l2_cid;

	write_unlock_bh(&l2cap_sk_list.lock);

done:
	release_sock(sk);
	return err;
}

static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr, int alen, int flags)
{
	struct sock *sk = sock->sk;
	struct sockaddr_l2 la;
	int len, err = 0;

	BT_DBG("sk %p type %d mode %d state %d", sk, sk->sk_type,
		l2cap_pi(sk)->mode, sk->sk_state);

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

	memset(&la, 0, sizeof(la));
	len = min_t(unsigned int, sizeof(la), alen);
	memcpy(&la, addr, len);

	if (la.l2_cid && la.l2_psm)
		return -EINVAL;

	lock_sock(sk);

	if ((sk->sk_type == SOCK_SEQPACKET || sk->sk_type == SOCK_STREAM)
		&& !(la.l2_psm || la.l2_cid || l2cap_pi(sk)->fixed_channel)) {
		err = -EINVAL;
		goto done;
	}

	switch (l2cap_pi(sk)->mode) {
	case L2CAP_MODE_BASIC:
		break;
	case L2CAP_MODE_ERTM:
	case L2CAP_MODE_STREAMING:
		if (!disable_ertm)
			break;
		/* fall through */
	default:
		err = -ENOTSUPP;
		goto done;
	}

	switch (sk->sk_state) {
	case BT_CONNECT:
	case BT_CONNECT2:
	case BT_CONFIG:
		/* Already connecting */
		goto wait;

	case BT_CONNECTED:
		/* Already connected */
		err = -EISCONN;
		goto done;

	case BT_OPEN:
	case BT_BOUND:
		/* Can connect */
		break;

	default:
		err = -EBADFD;
		goto done;
	}

	/* PSM must be odd and lsb of upper byte must be 0 */
	if ((__le16_to_cpu(la.l2_psm) & 0x0101) != 0x0001 &&
		!l2cap_pi(sk)->fixed_channel &&
				sk->sk_type != SOCK_RAW && !la.l2_cid) {
		BT_DBG("Bad PSM 0x%x", (int)__le16_to_cpu(la.l2_psm));
		err = -EINVAL;
		goto done;
	}

	/* Set destination address and psm */
	bacpy(&bt_sk(sk)->dst, &la.l2_bdaddr);
	l2cap_pi(sk)->psm = la.l2_psm;
	l2cap_pi(sk)->dcid = la.l2_cid;

	err = l2cap_do_connect(sk);
	if (err)
		goto done;

wait:
	err = bt_sock_wait_state(sk, BT_CONNECTED,
			sock_sndtimeo(sk, flags & O_NONBLOCK));
done:
	if (err)
		BT_ERR("failed %d", err);
	release_sock(sk);
	return err;
}

static int l2cap_sock_listen(struct socket *sock, int backlog)
{
	struct sock *sk = sock->sk;
	int err = 0;

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

	lock_sock(sk);

	if ((sock->type != SOCK_SEQPACKET && sock->type != SOCK_STREAM)
			|| sk->sk_state != BT_BOUND) {
		err = -EBADFD;
		goto done;
	}

	switch (l2cap_pi(sk)->mode) {
	case L2CAP_MODE_BASIC:
		break;
	case L2CAP_MODE_ERTM:
	case L2CAP_MODE_STREAMING:
		if (!disable_ertm)
			break;
		/* fall through */
	default:
		err = -ENOTSUPP;
		goto done;
	}

	if (!l2cap_pi(sk)->psm && !l2cap_pi(sk)->scid) {
		bdaddr_t *src = &bt_sk(sk)->src;
		u16 psm;

		err = -EINVAL;

		write_lock_bh(&l2cap_sk_list.lock);

		for (psm = 0x1001; psm < 0x1100; psm += 2)
			if (!__l2cap_get_sock_by_addr(cpu_to_le16(psm), src)) {
				l2cap_pi(sk)->psm   = cpu_to_le16(psm);
				l2cap_pi(sk)->sport = cpu_to_le16(psm);
				err = 0;
				break;
			}

		write_unlock_bh(&l2cap_sk_list.lock);

		if (err < 0)
			goto done;
	}

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

done:
	release_sock(sk);
	return err;
}

static int l2cap_sock_accept(struct socket *sock, struct socket *newsock, int flags)
{
	DECLARE_WAITQUEUE(wait, current);
	struct sock *sk = sock->sk, *nsk;
	long timeo;
	int err = 0;

	lock_sock_nested(sk, SINGLE_DEPTH_NESTING);

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

	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 (!(nsk = bt_accept_dequeue(sk, newsock))) {
		set_current_state(TASK_INTERRUPTIBLE);
		if (!timeo) {
			err = -EAGAIN;
			break;
		}

		release_sock(sk);
		timeo = schedule_timeout(timeo);
		lock_sock_nested(sk, SINGLE_DEPTH_NESTING);

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

		if (signal_pending(current)) {
			err = sock_intr_errno(timeo);
			break;
		}
	}
	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", nsk);

done:
	release_sock(sk);
	return err;
}

static int l2cap_sock_getname(struct socket *sock, struct sockaddr *addr, int *len, int peer)
{
	struct sockaddr_l2 *la = (struct sockaddr_l2 *) addr;
	struct sock *sk = sock->sk;

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

	addr->sa_family = AF_BLUETOOTH;
	*len = sizeof(struct sockaddr_l2);

	if (peer) {
		la->l2_psm = l2cap_pi(sk)->psm;
		bacpy(&la->l2_bdaddr, &bt_sk(sk)->dst);
		la->l2_cid = cpu_to_le16(l2cap_pi(sk)->dcid);
	} else {
		la->l2_psm = l2cap_pi(sk)->sport;
		bacpy(&la->l2_bdaddr, &bt_sk(sk)->src);
		la->l2_cid = cpu_to_le16(l2cap_pi(sk)->scid);
	}

	return 0;
}

static int l2cap_sock_getsockopt_old(struct socket *sock, int optname, char __user *optval, int __user *optlen)
{
	struct sock *sk = sock->sk;
	struct l2cap_options opts;
	struct l2cap_conninfo cinfo;
	int len, err = 0;
	u32 opt;

	BT_DBG("sk %p", sk);

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

	lock_sock(sk);

	switch (optname) {
	case L2CAP_OPTIONS:
		memset(&opts, 0, sizeof(opts));
		opts.imtu     = l2cap_pi(sk)->imtu;
		opts.omtu     = l2cap_pi(sk)->omtu;
		opts.flush_to = l2cap_pi(sk)->flush_to;
		opts.mode     = l2cap_pi(sk)->mode;
		opts.fcs      = l2cap_pi(sk)->fcs;
		opts.max_tx   = l2cap_pi(sk)->max_tx;
		opts.txwin_size = l2cap_pi(sk)->tx_win;

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

		break;

	case L2CAP_LM:
		switch (l2cap_pi(sk)->sec_level) {
		case BT_SECURITY_LOW:
			opt = L2CAP_LM_AUTH;
			break;
		case BT_SECURITY_MEDIUM:
			opt = L2CAP_LM_AUTH | L2CAP_LM_ENCRYPT;
			break;
		case BT_SECURITY_HIGH:
			opt = L2CAP_LM_AUTH | L2CAP_LM_ENCRYPT |
							L2CAP_LM_SECURE;
			break;
		default:
			opt = 0;
			break;
		}

		if (l2cap_pi(sk)->role_switch)
			opt |= L2CAP_LM_MASTER;

		if (l2cap_pi(sk)->force_reliable)
			opt |= L2CAP_LM_RELIABLE;

		if (l2cap_pi(sk)->flushable)
			opt |= L2CAP_LM_FLUSHABLE;

		if (put_user(opt, (u32 __user *) optval))
			err = -EFAULT;
		break;

	case L2CAP_CONNINFO:
		if (sk->sk_state != BT_CONNECTED &&
					!(sk->sk_state == BT_CONNECT2 &&
						bt_sk(sk)->defer_setup)) {
			err = -ENOTCONN;
			break;
		}

		cinfo.hci_handle = l2cap_pi(sk)->conn->hcon->handle;
		memcpy(cinfo.dev_class, l2cap_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 l2cap_sock_getsockopt(struct socket *sock, int level, int optname, char __user *optval, int __user *optlen)
{
	struct sock *sk = sock->sk;
	struct bt_security sec;
	struct bt_power pwr;
	int len, err = 0;

	BT_DBG("sk %p", sk);

	if (level == SOL_L2CAP)
		return l2cap_sock_getsockopt_old(sock, optname, optval, optlen);

	if (level != SOL_BLUETOOTH)
		return -ENOPROTOOPT;

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

	lock_sock(sk);

	switch (optname) {
	case BT_SECURITY:
		if (sk->sk_type != SOCK_SEQPACKET && sk->sk_type != SOCK_STREAM
				&& sk->sk_type != SOCK_RAW) {
			err = -EINVAL;
			break;
		}

		memset(&sec, 0, sizeof(sec));
		sec.level = l2cap_pi(sk)->sec_level;

		if (sk->sk_state == BT_CONNECTED)
			sec.key_size = l2cap_pi(sk)->conn->hcon->enc_key_size;

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

		break;

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

		if (put_user(bt_sk(sk)->defer_setup, (u32 __user *) optval))
			err = -EFAULT;

		break;

	case BT_POWER:
		if (sk->sk_type != SOCK_SEQPACKET && sk->sk_type != SOCK_STREAM
				&& sk->sk_type != SOCK_RAW) {
			err = -EINVAL;
			break;
		}

		pwr.force_active = l2cap_pi(sk)->force_active;

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

		break;

	case BT_AMP_POLICY:
		if (put_user(l2cap_pi(sk)->amp_pref, (u32 __user *) optval))
			err = -EFAULT;
		break;

	default:
		err = -ENOPROTOOPT;
		break;
	}

	release_sock(sk);
	return err;
}

static int l2cap_sock_setsockopt_old(struct socket *sock, int optname, char __user *optval, unsigned int optlen)
{
	struct sock *sk = sock->sk;
	struct l2cap_options opts;
	int len, le_sock, err = 0;
	u32 opt;

	BT_DBG("sk %p", sk);

	lock_sock(sk);

	le_sock = l2cap_pi(sk)->scid == L2CAP_CID_LE_DATA;

	switch (optname) {
	case L2CAP_OPTIONS:
		if (sk->sk_state == BT_CONNECTED && !le_sock) {
			err = -EINVAL;
			break;
		}

		opts.imtu     = l2cap_pi(sk)->imtu;
		opts.omtu     = l2cap_pi(sk)->omtu;
		opts.flush_to = l2cap_pi(sk)->flush_to;
		opts.mode     = l2cap_pi(sk)->mode;
		opts.fcs      = l2cap_pi(sk)->fcs;
		opts.max_tx   = l2cap_pi(sk)->max_tx;
		opts.txwin_size = l2cap_pi(sk)->tx_win;

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

		if ((opts.imtu || opts.omtu) && le_sock &&
				(sk->sk_state == BT_CONNECTED)) {
			if (opts.imtu >= L2CAP_LE_DEFAULT_MTU)
				l2cap_pi(sk)->imtu = opts.imtu;
			if (opts.omtu >= L2CAP_LE_DEFAULT_MTU)
				l2cap_pi(sk)->omtu = opts.omtu;
			if (opts.imtu < L2CAP_LE_DEFAULT_MTU ||
					opts.omtu < L2CAP_LE_DEFAULT_MTU)
				err = -EINVAL;
			break;
		}

		if (opts.txwin_size < 1 ||
			opts.txwin_size > L2CAP_TX_WIN_MAX_EXTENDED) {
			err = -EINVAL;
			break;
		}

		l2cap_pi(sk)->mode = opts.mode;
		switch (l2cap_pi(sk)->mode) {
		case L2CAP_MODE_BASIC:
			l2cap_pi(sk)->conf_state &= ~L2CAP_CONF_STATE2_DEVICE;
			break;
		case L2CAP_MODE_ERTM:
		case L2CAP_MODE_STREAMING:
			if (!disable_ertm)
				break;
			/* fall through */
		default:
			err = -EINVAL;
			break;
		}

		l2cap_pi(sk)->imtu = opts.imtu;
		l2cap_pi(sk)->omtu = opts.omtu;
		l2cap_pi(sk)->fcs  = opts.fcs;
		l2cap_pi(sk)->max_tx = opts.max_tx;
		l2cap_pi(sk)->tx_win = opts.txwin_size;
		break;

	case L2CAP_LM:
		if (get_user(opt, (u32 __user *) optval)) {
			err = -EFAULT;
			break;
		}

		if (opt & L2CAP_LM_AUTH)
			l2cap_pi(sk)->sec_level = BT_SECURITY_LOW;
		if (opt & L2CAP_LM_ENCRYPT)
			l2cap_pi(sk)->sec_level = BT_SECURITY_MEDIUM;
		if (opt & L2CAP_LM_SECURE)
			l2cap_pi(sk)->sec_level = BT_SECURITY_HIGH;

		l2cap_pi(sk)->role_switch    = (opt & L2CAP_LM_MASTER);
		l2cap_pi(sk)->force_reliable = (opt & L2CAP_LM_RELIABLE);
		l2cap_pi(sk)->flushable = (opt & L2CAP_LM_FLUSHABLE);
		break;

	default:
		err = -ENOPROTOOPT;
		break;
	}

	release_sock(sk);
	return err;
}

static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, char __user *optval, unsigned int optlen)
{
	struct sock *sk = sock->sk;
	struct bt_security sec;
	struct bt_power pwr;
	struct l2cap_conn *conn;
	int len, err = 0;
	u32 opt;

	BT_DBG("sk %p", sk);

	if (level == SOL_L2CAP)
		return l2cap_sock_setsockopt_old(sock, optname, optval, optlen);

	if (level != SOL_BLUETOOTH)
		return -ENOPROTOOPT;

	lock_sock(sk);

	switch (optname) {
	case BT_SECURITY:
		if (sk->sk_type != SOCK_SEQPACKET && sk->sk_type != SOCK_STREAM
				&& sk->sk_type != SOCK_RAW) {
			err = -EINVAL;
			break;
		}

		sec.level = BT_SECURITY_LOW;

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

		if (sec.level < BT_SECURITY_LOW ||
					sec.level > BT_SECURITY_HIGH) {
			err = -EINVAL;
			break;
		}

		l2cap_pi(sk)->sec_level = sec.level;

		conn = l2cap_pi(sk)->conn;
		if (conn && l2cap_pi(sk)->scid == L2CAP_CID_LE_DATA) {
			if (!conn->hcon->out) {
				err = -EINVAL;
				break;
			}

			if (smp_conn_security(conn, sec.level))
				break;

			err = 0;
			sk->sk_state = BT_CONFIG;
		}
		break;

	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;
		}

		bt_sk(sk)->defer_setup = opt;
		break;

	case BT_POWER:
		if (sk->sk_type != SOCK_SEQPACKET && sk->sk_type != SOCK_STREAM
				&& sk->sk_type != SOCK_RAW) {
			err = -EINVAL;
			break;
		}

		pwr.force_active = 1;

		len = min_t(unsigned int, sizeof(pwr), optlen);
		if (copy_from_user((char *) &pwr, optval, len)) {
			err = -EFAULT;
			break;
		}
		l2cap_pi(sk)->force_active = pwr.force_active;
		break;

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

		if ((opt > BT_AMP_POLICY_PREFER_BR_EDR) ||
			((l2cap_pi(sk)->mode != L2CAP_MODE_ERTM) &&
			 (l2cap_pi(sk)->mode != L2CAP_MODE_STREAMING))) {
			err = -EINVAL;
			break;
		}

		l2cap_pi(sk)->amp_pref = (u8) opt;
		BT_DBG("BT_AMP_POLICY now %d", opt);

		if ((sk->sk_state == BT_CONNECTED) &&
			(l2cap_pi(sk)->amp_move_role == L2CAP_AMP_MOVE_NONE))
			l2cap_amp_move_init(sk);

		break;

	default:
		err = -ENOPROTOOPT;
		break;
	}

	release_sock(sk);
	return err;
}

static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, size_t len)
{
	struct sock *sk = sock->sk;
	struct l2cap_pinfo *pi = l2cap_pi(sk);
	struct sk_buff *skb;
	struct sk_buff_head seg_queue;
	int err;
	u8 amp_id;

	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 = -ENOTCONN;
		goto done;
	}

	/* Connectionless channel */
	if (sk->sk_type == SOCK_DGRAM) {
		skb = l2cap_create_connless_pdu(sk, msg, len);
		if (IS_ERR(skb)) {
			err = PTR_ERR(skb);
		} else {
			l2cap_do_send(sk, skb);
			err = len;
		}
		goto done;
	}

	switch (pi->mode) {
	case L2CAP_MODE_BASIC:
		/* Check outgoing MTU */
		if (len > pi->omtu) {
			err = -EMSGSIZE;
			goto done;
		}

		/* Create a basic PDU */
		skb = l2cap_create_basic_pdu(sk, msg, len);
		if (IS_ERR(skb)) {
			err = PTR_ERR(skb);
			goto done;
		}

		l2cap_do_send(sk, skb);
		err = len;
		break;

	case L2CAP_MODE_ERTM:
	case L2CAP_MODE_STREAMING:

		/* Check outgoing MTU */
		if (len > pi->omtu) {
			err = -EMSGSIZE;
			goto done;
		}

		__skb_queue_head_init(&seg_queue);

		/* Do segmentation before calling in to the state machine,
		 * since it's possible to block while waiting for memory
		 * allocation.
		 */
		amp_id = pi->amp_id;
		err = l2cap_segment_sdu(sk, &seg_queue, msg, len, 0);

		/* The socket lock is released while segmenting, so check
		 * that the socket is still connected
		 */
		if (sk->sk_state != BT_CONNECTED) {
			__skb_queue_purge(&seg_queue);
			err = -ENOTCONN;
		}

		if (err) {
			BT_DBG("Error %d, sk_sndbuf %d, sk_wmem_alloc %d",
				err, sk->sk_sndbuf,
				atomic_read(&sk->sk_wmem_alloc));
			break;
		}

		if (pi->amp_id != amp_id) {
			/* Channel moved while unlocked. Resegment. */
			err = l2cap_resegment_queue(sk, &seg_queue);

			if (err)
				break;
		}

		if (pi->mode != L2CAP_MODE_STREAMING)
			err = l2cap_ertm_tx(sk, 0, &seg_queue,
				L2CAP_ERTM_EVENT_DATA_REQUEST);
		else
			err = l2cap_strm_tx(sk, &seg_queue);
		if (!err)
			err = len;

		/* If the skbs were not queued for sending, they'll still be in
		 * seg_queue and need to be purged.
		 */
		__skb_queue_purge(&seg_queue);
		break;

	default:
		BT_DBG("bad state %1.1x", pi->mode);
		err = -EBADFD;
	}

done:
	release_sock(sk);
	return err;
}

static int l2cap_sock_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, size_t len, int flags)
{
	struct sock *sk = sock->sk;
	int err;

	lock_sock(sk);

	if (sk->sk_state == BT_CONNECT2 && bt_sk(sk)->defer_setup) {
		struct l2cap_conn_rsp rsp;
		struct l2cap_conn *conn = l2cap_pi(sk)->conn;
		u8 buf[128];

		if (l2cap_pi(sk)->amp_id) {
			/* Physical link must be brought up before connection
			 * completes.
			 */
			amp_accept_physical(conn, l2cap_pi(sk)->amp_id, sk);
			release_sock(sk);
			return 0;
		}

		sk->sk_state = BT_CONFIG;

		rsp.scid   = cpu_to_le16(l2cap_pi(sk)->dcid);
		rsp.dcid   = cpu_to_le16(l2cap_pi(sk)->scid);
		rsp.result = cpu_to_le16(L2CAP_CR_SUCCESS);
		rsp.status = cpu_to_le16(L2CAP_CS_NO_INFO);
		l2cap_send_cmd(l2cap_pi(sk)->conn, l2cap_pi(sk)->ident,
					L2CAP_CONN_RSP, sizeof(rsp), &rsp);

		if (l2cap_pi(sk)->conf_state & L2CAP_CONF_REQ_SENT) {
			release_sock(sk);
			return 0;
		}

		l2cap_pi(sk)->conf_state |= L2CAP_CONF_REQ_SENT;
		l2cap_send_cmd(conn, l2cap_get_ident(conn), L2CAP_CONF_REQ,
				l2cap_build_conf_req(sk, buf), buf);
		l2cap_pi(sk)->num_conf_req++;

		release_sock(sk);
		return 0;
	}

	release_sock(sk);

	if (sock->type == SOCK_STREAM)
		err = bt_sock_stream_recvmsg(iocb, sock, msg, len, flags);
	else
		err = bt_sock_recvmsg(iocb, sock, msg, len, flags);

	l2cap_ertm_recv_done(sk);

	return err;
}

/* Kill socket (only if zapped and orphan)
 * Must be called on unlocked socket.
 */
void l2cap_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(&l2cap_sk_list, sk);
	sock_set_flag(sk, SOCK_DEAD);
	sock_put(sk);
}

/* Must be called on unlocked socket. */
static void l2cap_sock_close(struct sock *sk)
{
	l2cap_sock_clear_timer(sk);
	lock_sock(sk);
	__l2cap_sock_close(sk, ECONNRESET);
	release_sock(sk);
	l2cap_sock_kill(sk);
}

static void l2cap_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)))
		l2cap_sock_close(sk);

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

void __l2cap_sock_close(struct sock *sk, int reason)
{
	struct l2cap_conn *conn = l2cap_pi(sk)->conn;

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

	switch (sk->sk_state) {
	case BT_LISTEN:
		l2cap_sock_cleanup_listen(sk);
		break;

	case BT_CONNECTED:
	case BT_CONFIG:
		if ((sk->sk_type == SOCK_SEQPACKET ||
					sk->sk_type == SOCK_STREAM) &&
					conn->hcon->type == ACL_LINK) {
			l2cap_sock_set_timer(sk, sk->sk_sndtimeo);
			l2cap_send_disconn_req(conn, sk, reason);
		} else
			l2cap_chan_del(sk, reason);
		break;

	case BT_CONNECT2:
		if ((sk->sk_type == SOCK_SEQPACKET ||
					sk->sk_type == SOCK_STREAM) &&
					conn->hcon->type == ACL_LINK) {
			struct l2cap_conn_rsp rsp;
			__u16 result;

			if (bt_sk(sk)->defer_setup)
				result = L2CAP_CR_SEC_BLOCK;
			else
				result = L2CAP_CR_BAD_PSM;
			sk->sk_state = BT_DISCONN;

			rsp.scid   = cpu_to_le16(l2cap_pi(sk)->dcid);
			rsp.dcid   = cpu_to_le16(l2cap_pi(sk)->scid);
			rsp.result = cpu_to_le16(result);
			rsp.status = cpu_to_le16(L2CAP_CS_NO_INFO);
			l2cap_send_cmd(conn, l2cap_pi(sk)->ident,
					L2CAP_CONN_RSP, sizeof(rsp), &rsp);
		}

		l2cap_chan_del(sk, reason);
		break;

	case BT_CONNECT:
	case BT_DISCONN:
		l2cap_chan_del(sk, reason);
		break;

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

static int l2cap_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) {

		if (l2cap_pi(sk)->mode == L2CAP_MODE_ERTM) {
			err = __l2cap_wait_ack(sk);
			l2cap_ertm_shutdown(sk);
		}

		sk->sk_shutdown = SHUTDOWN_MASK;
		l2cap_sock_clear_timer(sk);
		__l2cap_sock_close(sk, 0);

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

	if (!err && sk->sk_err)
		err = -sk->sk_err;

	release_sock(sk);
	return err;
}

static int l2cap_sock_release(struct socket *sock)
{
	struct sock *sk = sock->sk;
	int err;

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

	if (!sk)
		return 0;

	err = l2cap_sock_shutdown(sock, 2);

	sock_orphan(sk);
	l2cap_sock_kill(sk);
	return err;
}

static void l2cap_sock_destruct(struct sock *sk)
{
	BT_DBG("sk %p", sk);

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

	l2cap_ertm_destruct(sk);
}

static void set_default_config(struct l2cap_conf_prm *conf_prm)
{
	conf_prm->fcs = L2CAP_FCS_CRC16;
	conf_prm->retrans_timeout = 0;
	conf_prm->monitor_timeout = 0;
	conf_prm->flush_to = L2CAP_DEFAULT_FLUSH_TO;
}

void l2cap_sock_init(struct sock *sk, struct sock *parent)
{
	struct l2cap_pinfo *pi = l2cap_pi(sk);

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

	if (parent) {
		sk->sk_type = parent->sk_type;
		sk->sk_rcvbuf = parent->sk_rcvbuf;
		sk->sk_sndbuf = parent->sk_sndbuf;
		bt_sk(sk)->defer_setup = bt_sk(parent)->defer_setup;

		pi->imtu = l2cap_pi(parent)->imtu;
		pi->omtu = l2cap_pi(parent)->omtu;
		pi->conf_state = l2cap_pi(parent)->conf_state;
		pi->mode = l2cap_pi(parent)->mode;
		pi->fcs  = l2cap_pi(parent)->fcs;
		pi->max_tx = l2cap_pi(parent)->max_tx;
		pi->tx_win = l2cap_pi(parent)->tx_win;
		pi->sec_level = l2cap_pi(parent)->sec_level;
		pi->role_switch = l2cap_pi(parent)->role_switch;
		pi->force_reliable = l2cap_pi(parent)->force_reliable;
		pi->flushable = l2cap_pi(parent)->flushable;
		pi->force_active = l2cap_pi(parent)->force_active;
		pi->amp_pref = l2cap_pi(parent)->amp_pref;
	} else {
		pi->imtu = L2CAP_DEFAULT_MTU;
		pi->omtu = 0;
		if (!disable_ertm && sk->sk_type == SOCK_STREAM) {
			pi->mode = L2CAP_MODE_ERTM;
			pi->conf_state |= L2CAP_CONF_STATE2_DEVICE;
		} else {
			pi->mode = L2CAP_MODE_BASIC;
		}
		pi->reconf_state = L2CAP_RECONF_NONE;
		pi->max_tx = L2CAP_DEFAULT_MAX_TX;
		pi->fcs = L2CAP_FCS_CRC16;
		pi->tx_win = L2CAP_DEFAULT_TX_WINDOW;
		pi->sec_level = BT_SECURITY_LOW;
		pi->role_switch = 0;
		pi->force_reliable = 0;
		pi->flushable = 0;
		pi->force_active = 1;
		pi->amp_pref = BT_AMP_POLICY_REQUIRE_BR_EDR;
	}

	/* Default config options */
	sk->sk_backlog_rcv = l2cap_data_channel;
	pi->ampcon = NULL;
	pi->ampchan = NULL;
	pi->conf_len = 0;
	pi->flush_to = L2CAP_DEFAULT_FLUSH_TO;
	pi->scid = 0;
	pi->dcid = 0;
	pi->tx_win_max = L2CAP_TX_WIN_MAX_ENHANCED;
	pi->extended_control = 0;

	pi->local_conf.fcs = pi->fcs;
	if (pi->mode == L2CAP_MODE_BASIC) {
		pi->local_conf.retrans_timeout = 0;
		pi->local_conf.monitor_timeout = 0;
	} else {
		pi->local_conf.retrans_timeout = L2CAP_DEFAULT_RETRANS_TO;
		pi->local_conf.monitor_timeout = L2CAP_DEFAULT_MONITOR_TO;
	}

	pi->local_conf.flush_to = pi->flush_to;

	set_default_config(&pi->remote_conf);

	skb_queue_head_init(TX_QUEUE(sk));
	skb_queue_head_init(SREJ_QUEUE(sk));
}

static struct proto l2cap_proto = {
	.name		= "L2CAP",
	.owner		= THIS_MODULE,
	.obj_size	= sizeof(struct l2cap_pinfo)
};

struct sock *l2cap_sock_alloc(struct net *net, struct socket *sock, int proto, gfp_t prio)
{
	struct sock *sk;

	sk = sk_alloc(net, PF_BLUETOOTH, prio, &l2cap_proto);
	if (!sk)
		return NULL;

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

	sk->sk_destruct = l2cap_sock_destruct;
	sk->sk_sndtimeo = msecs_to_jiffies(L2CAP_CONN_TIMEOUT);

	sock_reset_flag(sk, SOCK_ZAPPED);

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

	setup_timer(&sk->sk_timer, l2cap_sock_timeout, (unsigned long) sk);

	bt_sock_link(&l2cap_sk_list, sk);
	return sk;
}

static int l2cap_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 && sock->type != SOCK_STREAM &&
			sock->type != SOCK_DGRAM && sock->type != SOCK_RAW)
		return -ESOCKTNOSUPPORT;

	if (sock->type == SOCK_RAW && !kern && !capable(CAP_NET_RAW))
		return -EPERM;

	sock->ops = &l2cap_sock_ops;

	sk = l2cap_sock_alloc(net, sock, protocol, GFP_ATOMIC);
	if (!sk)
		return -ENOMEM;

	l2cap_sock_init(sk, NULL);
	return 0;
}

const struct proto_ops l2cap_sock_ops = {
	.family		= PF_BLUETOOTH,
	.owner		= THIS_MODULE,
	.release	= l2cap_sock_release,
	.bind		= l2cap_sock_bind,
	.connect	= l2cap_sock_connect,
	.listen		= l2cap_sock_listen,
	.accept		= l2cap_sock_accept,
	.getname	= l2cap_sock_getname,
	.sendmsg	= l2cap_sock_sendmsg,
	.recvmsg	= l2cap_sock_recvmsg,
	.poll		= bt_sock_poll,
	.ioctl		= bt_sock_ioctl,
	.mmap		= sock_no_mmap,
	.socketpair	= sock_no_socketpair,
	.shutdown	= l2cap_sock_shutdown,
	.setsockopt	= l2cap_sock_setsockopt,
	.getsockopt	= l2cap_sock_getsockopt
};

static const struct net_proto_family l2cap_sock_family_ops = {
	.family	= PF_BLUETOOTH,
	.owner	= THIS_MODULE,
	.create	= l2cap_sock_create,
};

int __init l2cap_init_sockets(void)
{
	int err;

	err = proto_register(&l2cap_proto, 0);
	if (err < 0)
		return err;

	err = bt_sock_register(BTPROTO_L2CAP, &l2cap_sock_family_ops);
	if (err < 0)
		goto error;

	BT_INFO("L2CAP socket layer initialized");

	return 0;

error:
	BT_ERR("L2CAP socket registration failed");
	proto_unregister(&l2cap_proto);
	return err;
}

void l2cap_cleanup_sockets(void)
{
	if (bt_sock_unregister(BTPROTO_L2CAP) < 0)
		BT_ERR("L2CAP socket unregistration failed");

	proto_unregister(&l2cap_proto);
}