/*
   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 L2CAP core and sockets. */

#include <linux/module.h>

#include <linux/types.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/list.h>
#include <linux/device.h>
#include <net/sock.h>

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/unaligned.h>

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

#define VERSION "2.13"

static u32 l2cap_feat_mask = 0x0080;
static u8 l2cap_fixed_chan[8] = { 0x02, };

static const struct proto_ops l2cap_sock_ops;

static struct bt_sock_list l2cap_sk_list = {
        .lock = __RW_LOCK_UNLOCKED(l2cap_sk_list.lock)
};

static void __l2cap_sock_close(struct sock *sk, int reason);
static void l2cap_sock_close(struct sock *sk);
static void l2cap_sock_kill(struct sock *sk);

static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn,
                                u8 code, u8 ident, u16 dlen, void *data);

/* ---- 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 (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);
}

static 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);
}

static 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);
}

/* ---- L2CAP channels ---- */
static struct sock *__l2cap_get_chan_by_dcid(struct l2cap_chan_list *l, u16 cid)
{
        struct sock *s;
        for (s = l->head; s; s = l2cap_pi(s)->next_c) {
                if (l2cap_pi(s)->dcid == cid)
                        break;
        }
        return s;
}

static struct sock *__l2cap_get_chan_by_scid(struct l2cap_chan_list *l, u16 cid)
{
        struct sock *s;
        for (s = l->head; s; s = l2cap_pi(s)->next_c) {
                if (l2cap_pi(s)->scid == cid)
                        break;
        }
        return s;
}

/* Find channel with given SCID.
 * Returns locked socket */
static inline struct sock *l2cap_get_chan_by_scid(struct l2cap_chan_list *l, u16 cid)
{
        struct sock *s;
        read_lock(&l->lock);
        s = __l2cap_get_chan_by_scid(l, cid);
        if (s) bh_lock_sock(s);
        read_unlock(&l->lock);
        return s;
}

static struct sock *__l2cap_get_chan_by_ident(struct l2cap_chan_list *l, u8 ident)
{
        struct sock *s;
        for (s = l->head; s; s = l2cap_pi(s)->next_c) {
                if (l2cap_pi(s)->ident == ident)
                        break;
        }
        return s;
}

static inline struct sock *l2cap_get_chan_by_ident(struct l2cap_chan_list *l, u8 ident)
{
        struct sock *s;
        read_lock(&l->lock);
        s = __l2cap_get_chan_by_ident(l, ident);
        if (s) bh_lock_sock(s);
        read_unlock(&l->lock);
        return s;
}

static u16 l2cap_alloc_cid(struct l2cap_chan_list *l)
{
        u16 cid = 0x0040;

        for (; cid < 0xffff; cid++) {
                if(!__l2cap_get_chan_by_scid(l, cid))
                        return cid;
        }

        return 0;
}

static inline void __l2cap_chan_link(struct l2cap_chan_list *l, struct sock *sk)
{
        sock_hold(sk);

        if (l->head)
                l2cap_pi(l->head)->prev_c = sk;

        l2cap_pi(sk)->next_c = l->head;
        l2cap_pi(sk)->prev_c = NULL;
        l->head = sk;
}

static inline void l2cap_chan_unlink(struct l2cap_chan_list *l, struct sock *sk)
{
        struct sock *next = l2cap_pi(sk)->next_c, *prev = l2cap_pi(sk)->prev_c;

        write_lock_bh(&l->lock);
        if (sk == l->head)
                l->head = next;

        if (next)
                l2cap_pi(next)->prev_c = prev;
        if (prev)
                l2cap_pi(prev)->next_c = next;
        write_unlock_bh(&l->lock);

        __sock_put(sk);
}

static void __l2cap_chan_add(struct l2cap_conn *conn, struct sock *sk, struct sock *parent)
{
        struct l2cap_chan_list *l = &conn->chan_list;

        BT_DBG("conn %p, psm 0x%2.2x, dcid 0x%4.4x", conn, l2cap_pi(sk)->psm, l2cap_pi(sk)->dcid);

        conn->disc_reason = 0x13;

        l2cap_pi(sk)->conn = conn;

        if (sk->sk_type == SOCK_SEQPACKET) {
                /* Alloc CID for connection-oriented socket */
                l2cap_pi(sk)->scid = l2cap_alloc_cid(l);
        } else if (sk->sk_type == SOCK_DGRAM) {
                /* Connectionless socket */
                l2cap_pi(sk)->scid = 0x0002;
                l2cap_pi(sk)->dcid = 0x0002;
                l2cap_pi(sk)->omtu = L2CAP_DEFAULT_MTU;
        } else {
                /* Raw socket can send/recv signalling messages only */
                l2cap_pi(sk)->scid = 0x0001;
                l2cap_pi(sk)->dcid = 0x0001;
                l2cap_pi(sk)->omtu = L2CAP_DEFAULT_MTU;
        }

        __l2cap_chan_link(l, sk);

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

/* Delete channel.
 * Must be called on the locked socket. */
static void l2cap_chan_del(struct sock *sk, int err)
{
        struct l2cap_conn *conn = l2cap_pi(sk)->conn;
        struct sock *parent = bt_sk(sk)->parent;

        l2cap_sock_clear_timer(sk);

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

        if (conn) {
                /* Unlink from channel list */
                l2cap_chan_unlink(&conn->chan_list, sk);
                l2cap_pi(sk)->conn = NULL;
                hci_conn_put(conn->hcon);
        }

        sk->sk_state = BT_CLOSED;
        sock_set_flag(sk, SOCK_ZAPPED);

        if (err)
                sk->sk_err = err;

        if (parent) {
                bt_accept_unlink(sk);
                parent->sk_data_ready(parent, 0);
        } else
                sk->sk_state_change(sk);
}

/* Service level security */
static inline int l2cap_check_security(struct sock *sk)
{
        struct l2cap_conn *conn = l2cap_pi(sk)->conn;
        __u8 auth_type;

        if (l2cap_pi(sk)->psm == cpu_to_le16(0x0001)) {
                if (l2cap_pi(sk)->sec_level == BT_SECURITY_HIGH)
                        auth_type = HCI_AT_NO_BONDING_MITM;
                else
                        auth_type = HCI_AT_NO_BONDING;

                if (l2cap_pi(sk)->sec_level == BT_SECURITY_LOW)
                        l2cap_pi(sk)->sec_level = BT_SECURITY_SDP;
        } else {
                switch (l2cap_pi(sk)->sec_level) {
                case BT_SECURITY_HIGH:
                        auth_type = HCI_AT_GENERAL_BONDING_MITM;
                        break;
                case BT_SECURITY_MEDIUM:
                        auth_type = HCI_AT_GENERAL_BONDING;
                        break;
                default:
                        auth_type = HCI_AT_NO_BONDING;
                        break;
                }
        }

        return hci_conn_security(conn->hcon, l2cap_pi(sk)->sec_level,
                                                                auth_type);
}

static inline u8 l2cap_get_ident(struct l2cap_conn *conn)
{
        u8 id;

        /* Get next available identificator.
         *    1 - 128 are used by kernel.
         *  129 - 199 are reserved.
         *  200 - 254 are used by utilities like l2ping, etc.
         */

        spin_lock_bh(&conn->lock);

        if (++conn->tx_ident > 128)
                conn->tx_ident = 1;

        id = conn->tx_ident;

        spin_unlock_bh(&conn->lock);

        return id;
}

static inline int l2cap_send_cmd(struct l2cap_conn *conn, u8 ident, u8 code, u16 len, void *data)
{
        struct sk_buff *skb = l2cap_build_cmd(conn, code, ident, len, data);

        BT_DBG("code 0x%2.2x", code);

        if (!skb)
                return -ENOMEM;

        return hci_send_acl(conn->hcon, skb, 0);
}

static void l2cap_do_start(struct sock *sk)
{
        struct l2cap_conn *conn = l2cap_pi(sk)->conn;

        if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT) {
                if (!(conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_DONE))
                        return;

                if (l2cap_check_security(sk)) {
                        struct l2cap_conn_req req;
                        req.scid = cpu_to_le16(l2cap_pi(sk)->scid);
                        req.psm  = l2cap_pi(sk)->psm;

                        l2cap_pi(sk)->ident = l2cap_get_ident(conn);

                        l2cap_send_cmd(conn, l2cap_pi(sk)->ident,
                                        L2CAP_CONN_REQ, sizeof(req), &req);
                }
        } else {
                struct l2cap_info_req req;
                req.type = cpu_to_le16(L2CAP_IT_FEAT_MASK);

                conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_SENT;
                conn->info_ident = l2cap_get_ident(conn);

                mod_timer(&conn->info_timer, jiffies +
                                        msecs_to_jiffies(L2CAP_INFO_TIMEOUT));

                l2cap_send_cmd(conn, conn->info_ident,
                                        L2CAP_INFO_REQ, sizeof(req), &req);
        }
}

/* ---- L2CAP connections ---- */
static void l2cap_conn_start(struct l2cap_conn *conn)
{
        struct l2cap_chan_list *l = &conn->chan_list;
        struct sock *sk;

        BT_DBG("conn %p", conn);

        read_lock(&l->lock);

        for (sk = l->head; sk; sk = l2cap_pi(sk)->next_c) {
                bh_lock_sock(sk);

                if (sk->sk_type != SOCK_SEQPACKET) {
                        bh_unlock_sock(sk);
                        continue;
                }

                if (sk->sk_state == BT_CONNECT) {
                        if (l2cap_check_security(sk)) {
                                struct l2cap_conn_req req;
                                req.scid = cpu_to_le16(l2cap_pi(sk)->scid);
                                req.psm  = l2cap_pi(sk)->psm;

                                l2cap_pi(sk)->ident = l2cap_get_ident(conn);

                                l2cap_send_cmd(conn, l2cap_pi(sk)->ident,
                                        L2CAP_CONN_REQ, sizeof(req), &req);
                        }
                } else if (sk->sk_state == BT_CONNECT2) {
                        struct l2cap_conn_rsp rsp;
                        rsp.scid = cpu_to_le16(l2cap_pi(sk)->dcid);
                        rsp.dcid = cpu_to_le16(l2cap_pi(sk)->scid);

                        if (l2cap_check_security(sk)) {
                                if (bt_sk(sk)->defer_setup) {
                                        struct sock *parent = bt_sk(sk)->parent;
                                        rsp.result = cpu_to_le16(L2CAP_CR_PEND);
                                        rsp.status = cpu_to_le16(L2CAP_CS_AUTHOR_PEND);
                                        parent->sk_data_ready(parent, 0);

                                } else {
                                        sk->sk_state = BT_CONFIG;
                                        rsp.result = cpu_to_le16(L2CAP_CR_SUCCESS);
                                        rsp.status = cpu_to_le16(L2CAP_CS_NO_INFO);
                                }
                        } else {
                                rsp.result = cpu_to_le16(L2CAP_CR_PEND);
                                rsp.status = cpu_to_le16(L2CAP_CS_AUTHEN_PEND);
                        }

                        l2cap_send_cmd(conn, l2cap_pi(sk)->ident,
                                        L2CAP_CONN_RSP, sizeof(rsp), &rsp);
                }

                bh_unlock_sock(sk);
        }

        read_unlock(&l->lock);
}

static void l2cap_conn_ready(struct l2cap_conn *conn)
{
        struct l2cap_chan_list *l = &conn->chan_list;
        struct sock *sk;

        BT_DBG("conn %p", conn);

        read_lock(&l->lock);

        for (sk = l->head; sk; sk = l2cap_pi(sk)->next_c) {
                bh_lock_sock(sk);

                if (sk->sk_type != SOCK_SEQPACKET) {
                        l2cap_sock_clear_timer(sk);
                        sk->sk_state = BT_CONNECTED;
                        sk->sk_state_change(sk);
                } else if (sk->sk_state == BT_CONNECT)
                        l2cap_do_start(sk);

                bh_unlock_sock(sk);
        }

        read_unlock(&l->lock);
}

/* Notify sockets that we cannot guaranty reliability anymore */
static void l2cap_conn_unreliable(struct l2cap_conn *conn, int err)
{
        struct l2cap_chan_list *l = &conn->chan_list;
        struct sock *sk;

        BT_DBG("conn %p", conn);

        read_lock(&l->lock);

        for (sk = l->head; sk; sk = l2cap_pi(sk)->next_c) {
                if (l2cap_pi(sk)->force_reliable)
                        sk->sk_err = err;
        }

        read_unlock(&l->lock);
}

static void l2cap_info_timeout(unsigned long arg)
{
        struct l2cap_conn *conn = (void *) arg;

        conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;
        conn->info_ident = 0;

        l2cap_conn_start(conn);
}

static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
{
        struct l2cap_conn *conn = hcon->l2cap_data;

        if (conn || status)
                return conn;

        conn = kzalloc(sizeof(struct l2cap_conn), GFP_ATOMIC);
        if (!conn)
                return NULL;

        hcon->l2cap_data = conn;
        conn->hcon = hcon;

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

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

        conn->feat_mask = 0;

        setup_timer(&conn->info_timer, l2cap_info_timeout,
                                                (unsigned long) conn);

        spin_lock_init(&conn->lock);
        rwlock_init(&conn->chan_list.lock);

        conn->disc_reason = 0x13;

        return conn;
}

static void l2cap_conn_del(struct hci_conn *hcon, int err)
{
        struct l2cap_conn *conn = hcon->l2cap_data;
        struct sock *sk;

        if (!conn)
                return;

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

        kfree_skb(conn->rx_skb);

        /* Kill channels */
        while ((sk = conn->chan_list.head)) {
                bh_lock_sock(sk);
                l2cap_chan_del(sk, err);
                bh_unlock_sock(sk);
                l2cap_sock_kill(sk);
        }

        if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT)
                del_timer_sync(&conn->info_timer);

        hcon->l2cap_data = NULL;
        kfree(conn);
}

static inline void l2cap_chan_add(struct l2cap_conn *conn, struct sock *sk, struct sock *parent)
{
        struct l2cap_chan_list *l = &conn->chan_list;
        write_lock_bh(&l->lock);
        __l2cap_chan_add(conn, sk, parent);
        write_unlock_bh(&l->lock);
}

/* ---- Socket interface ---- */
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;
}

/* Find socket with psm and source bdaddr.
 * Returns closest match.
 */
static struct sock *__l2cap_get_sock_by_psm(int state, __le16 psm, bdaddr_t *src)
{
        struct sock *sk = NULL, *sk1 = NULL;
        struct hlist_node *node;

        sk_for_each(sk, node, &l2cap_sk_list.head) {
                if (state && sk->sk_state != state)
                        continue;

                if (l2cap_pi(sk)->psm == psm) {
                        /* Exact match. */
                        if (!bacmp(&bt_sk(sk)->src, src))
                                break;

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

/* Find socket with given address (psm, src).
 * Returns locked socket */
static inline struct sock *l2cap_get_sock_by_psm(int state, __le16 psm, bdaddr_t *src)
{
        struct sock *s;
        read_lock(&l2cap_sk_list.lock);
        s = __l2cap_get_sock_by_psm(state, psm, src);
        if (s) bh_lock_sock(s);
        read_unlock(&l2cap_sk_list.lock);
        return s;
}

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);
}

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);
}

/* Kill socket (only if zapped and orphan)
 * Must be called on unlocked socket.
 */
static 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);
}

static void __l2cap_sock_close(struct sock *sk, int reason)
{
        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) {
                        struct l2cap_conn *conn = l2cap_pi(sk)->conn;
                        struct l2cap_disconn_req req;

                        sk->sk_state = BT_DISCONN;
                        l2cap_sock_set_timer(sk, sk->sk_sndtimeo);

                        req.dcid = cpu_to_le16(l2cap_pi(sk)->dcid);
                        req.scid = cpu_to_le16(l2cap_pi(sk)->scid);
                        l2cap_send_cmd(conn, l2cap_get_ident(conn),
                                        L2CAP_DISCONN_REQ, sizeof(req), &req);
                } else
                        l2cap_chan_del(sk, reason);
                break;

        case BT_CONNECT2:
                if (sk->sk_type == SOCK_SEQPACKET) {
                        struct l2cap_conn *conn = l2cap_pi(sk)->conn;
                        struct l2cap_conn_rsp rsp;
                        __u16 result;

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

                        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);
                } else
                        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;
        }
}

/* 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_init(struct sock *sk, struct sock *parent)
{
        struct l2cap_pinfo *pi = l2cap_pi(sk);

        BT_DBG("sk %p", sk);

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

                pi->imtu = l2cap_pi(parent)->imtu;
                pi->omtu = l2cap_pi(parent)->omtu;
                pi->sec_level = l2cap_pi(parent)->sec_level;
                pi->role_switch = l2cap_pi(parent)->role_switch;
                pi->force_reliable = l2cap_pi(parent)->force_reliable;
        } else {
                pi->imtu = L2CAP_DEFAULT_MTU;
                pi->omtu = 0;
                pi->sec_level = BT_SECURITY_LOW;
                pi->role_switch = 0;
                pi->force_reliable = 0;
        }

        /* Default config options */
        pi->conf_len = 0;
        pi->flush_to = L2CAP_DEFAULT_FLUSH_TO;
}

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

static 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)
{
        struct sock *sk;

        BT_DBG("sock %p", sock);

        sock->state = SS_UNCONNECTED;

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

        if (sock->type == SOCK_RAW && !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;
}

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)
                return -EINVAL;

        lock_sock(sk);

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

        if (la.l2_psm && btohs(la.l2_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 (btohs(la.l2_psm) == 0x0001 || btohs(la.l2_psm) == 0x0003)
                        l2cap_pi(sk)->sec_level = BT_SECURITY_SDP;
        }

        write_unlock_bh(&l2cap_sk_list.lock);

done:
        release_sock(sk);
        return err;
}

static int l2cap_do_connect(struct sock *sk)
{
        bdaddr_t *src = &bt_sk(sk)->src;
        bdaddr_t *dst = &bt_sk(sk)->dst;
        struct l2cap_conn *conn;
        struct hci_conn *hcon;
        struct hci_dev *hdev;
        __u8 auth_type;
        int err = 0;

        BT_DBG("%s -> %s psm 0x%2.2x", batostr(src), batostr(dst),
                                                        l2cap_pi(sk)->psm);

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

        hci_dev_lock_bh(hdev);

        err = -ENOMEM;

        if (sk->sk_type == SOCK_RAW) {
                switch (l2cap_pi(sk)->sec_level) {
                case BT_SECURITY_HIGH:
                        auth_type = HCI_AT_DEDICATED_BONDING_MITM;
                        break;
                case BT_SECURITY_MEDIUM:
                        auth_type = HCI_AT_DEDICATED_BONDING;
                        break;
                default:
                        auth_type = HCI_AT_NO_BONDING;
                        break;
                }
        } else if (l2cap_pi(sk)->psm == cpu_to_le16(0x0001)) {
                if (l2cap_pi(sk)->sec_level == BT_SECURITY_HIGH)
                        auth_type = HCI_AT_NO_BONDING_MITM;
                else
                        auth_type = HCI_AT_NO_BONDING;

                if (l2cap_pi(sk)->sec_level == BT_SECURITY_LOW)
                        l2cap_pi(sk)->sec_level = BT_SECURITY_SDP;
        } else {
                switch (l2cap_pi(sk)->sec_level) {
                case BT_SECURITY_HIGH:
                        auth_type = HCI_AT_GENERAL_BONDING_MITM;
                        break;
                case BT_SECURITY_MEDIUM:
                        auth_type = HCI_AT_GENERAL_BONDING;
                        break;
                default:
                        auth_type = HCI_AT_NO_BONDING;
                        break;
                }
        }

        hcon = hci_connect(hdev, ACL_LINK, dst,
                                        l2cap_pi(sk)->sec_level, auth_type);
        if (!hcon)
                goto done;

        conn = l2cap_conn_add(hcon, 0);
        if (!conn) {
                hci_conn_put(hcon);
                goto done;
        }

        err = 0;

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

        l2cap_chan_add(conn, sk, NULL);

        sk->sk_state = BT_CONNECT;
        l2cap_sock_set_timer(sk, sk->sk_sndtimeo);

        if (hcon->state == BT_CONNECTED) {
                if (sk->sk_type != SOCK_SEQPACKET) {
                        l2cap_sock_clear_timer(sk);
                        sk->sk_state = BT_CONNECTED;
                } else
                        l2cap_do_start(sk);
        }

done:
        hci_dev_unlock_bh(hdev);
        hci_dev_put(hdev);
        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", 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)
                return -EINVAL;

        lock_sock(sk);

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

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

        case BT_CONNECTED:
                /* Already connected */
                goto done;

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

        default:
                err = -EBADFD;
                goto done;
        }

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

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

wait:
        err = bt_sock_wait_state(sk, BT_CONNECTED,
                        sock_sndtimeo(sk, flags & O_NONBLOCK));
done:
        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 (sk->sk_state != BT_BOUND || sock->type != SOCK_SEQPACKET) {
                err = -EBADFD;
                goto done;

        }

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

        return 0;
}

static inline int l2cap_do_send(struct sock *sk, struct msghdr *msg, int len)
{
        struct l2cap_conn *conn = l2cap_pi(sk)->conn;
        struct sk_buff *skb, **frag;
        int err, hlen, count, sent=0;
        struct l2cap_hdr *lh;

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

        /* First fragment (with L2CAP header) */
        if (sk->sk_type == SOCK_DGRAM)
                hlen = L2CAP_HDR_SIZE + 2;
        else
                hlen = L2CAP_HDR_SIZE;

        count = min_t(unsigned int, (conn->mtu - hlen), len);

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

        /* Create L2CAP header */
        lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
        lh->cid = cpu_to_le16(l2cap_pi(sk)->dcid);
        lh->len = cpu_to_le16(len + (hlen - L2CAP_HDR_SIZE));

        if (sk->sk_type == SOCK_DGRAM)
                put_unaligned(l2cap_pi(sk)->psm, (__le16 *) skb_put(skb, 2));

        if (memcpy_fromiovec(skb_put(skb, count), msg->msg_iov, count)) {
                err = -EFAULT;
                goto fail;
        }

        sent += count;
        len  -= count;

        /* Continuation fragments (no L2CAP header) */
        frag = &skb_shinfo(skb)->frag_list;
        while (len) {
                count = min_t(unsigned int, conn->mtu, len);

                *frag = bt_skb_send_alloc(sk, count, msg->msg_flags & MSG_DONTWAIT, &err);
                if (!*frag)
                        goto fail;

                if (memcpy_fromiovec(skb_put(*frag, count), msg->msg_iov, count)) {
                        err = -EFAULT;
                        goto fail;
                }

                sent += count;
                len  -= count;

                frag = &(*frag)->next;
        }

        if ((err = hci_send_acl(conn->hcon, skb, 0)) < 0)
                goto fail;

        return sent;

fail:
        kfree_skb(skb);
        return err;
}

static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, size_t len)
{
        struct sock *sk = sock->sk;
        int err = 0;

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

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

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

        /* Check outgoing MTU */
        if (sk->sk_type != SOCK_RAW && len > l2cap_pi(sk)->omtu)
                return -EINVAL;

        lock_sock(sk);

        if (sk->sk_state == BT_CONNECTED)
                err = l2cap_do_send(sk, msg, len);
        else
                err = -ENOTCONN;

        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;

        lock_sock(sk);

        if (sk->sk_state == BT_CONNECT2 && bt_sk(sk)->defer_setup) {
                struct l2cap_conn_rsp rsp;

                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);

                release_sock(sk);
                return 0;
        }

        release_sock(sk);

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

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

        BT_DBG("sk %p", sk);

        lock_sock(sk);

        switch (optname) {
        case L2CAP_OPTIONS:
                opts.imtu     = l2cap_pi(sk)->imtu;
                opts.omtu     = l2cap_pi(sk)->omtu;
                opts.flush_to = l2cap_pi(sk)->flush_to;
                opts.mode     = L2CAP_MODE_BASIC;

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

                l2cap_pi(sk)->imtu  = opts.imtu;
                l2cap_pi(sk)->omtu  = opts.omtu;
                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);
                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, int optlen)
{
        struct sock *sk = sock->sk;
        struct bt_security sec;
        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_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;
                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;

        default:
                err = -ENOPROTOOPT;
                break;
        }

        release_sock(sk);
        return err;
}

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:
                opts.imtu     = l2cap_pi(sk)->imtu;
                opts.omtu     = l2cap_pi(sk)->omtu;
                opts.flush_to = l2cap_pi(sk)->flush_to;
                opts.mode     = L2CAP_MODE_BASIC;

                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 (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;
        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_RAW) {
                        err = -EINVAL;
                        break;
                }

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

                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;

        default:
                err = -ENOPROTOOPT;
                break;
        }

        release_sock(sk);
        return err;
}

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) {
                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);
        }
        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_chan_ready(struct sock *sk)
{
        struct sock *parent = bt_sk(sk)->parent;

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

        l2cap_pi(sk)->conf_state = 0;
        l2cap_sock_clear_timer(sk);

        if (!parent) {
                /* Outgoing channel.
                 * Wake up socket sleeping on connect.
                 */
                sk->sk_state = BT_CONNECTED;
                sk->sk_state_change(sk);
        } else {
                /* Incoming channel.
                 * Wake up socket sleeping on accept.
                 */
                parent->sk_data_ready(parent, 0);
        }
}

/* Copy frame to all raw sockets on that connection */
static void l2cap_raw_recv(struct l2cap_conn *conn, struct sk_buff *skb)
{
        struct l2cap_chan_list *l = &conn->chan_list;
        struct sk_buff *nskb;
        struct sock * sk;

        BT_DBG("conn %p", conn);

        read_lock(&l->lock);
        for (sk = l->head; sk; sk = l2cap_pi(sk)->next_c) {
                if (sk->sk_type != SOCK_RAW)
                        continue;

                /* Don't send frame to the socket it came from */
                if (skb->sk == sk)
                        continue;

                if (!(nskb = skb_clone(skb, GFP_ATOMIC)))
                        continue;

                if (sock_queue_rcv_skb(sk, nskb))
                        kfree_skb(nskb);
        }
        read_unlock(&l->lock);
}

/* ---- L2CAP signalling commands ---- */
static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn,
                                u8 code, u8 ident, u16 dlen, void *data)
{
        struct sk_buff *skb, **frag;
        struct l2cap_cmd_hdr *cmd;
        struct l2cap_hdr *lh;
        int len, count;

        BT_DBG("conn %p, code 0x%2.2x, ident 0x%2.2x, len %d", conn, code, ident, dlen);

        len = L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE + dlen;
        count = min_t(unsigned int, conn->mtu, len);

        skb = bt_skb_alloc(count, GFP_ATOMIC);
        if (!skb)
                return NULL;

        lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
        lh->len = cpu_to_le16(L2CAP_CMD_HDR_SIZE + dlen);
        lh->cid = cpu_to_le16(0x0001);

        cmd = (struct l2cap_cmd_hdr *) skb_put(skb, L2CAP_CMD_HDR_SIZE);
        cmd->code  = code;
        cmd->ident = ident;
        cmd->len   = cpu_to_le16(dlen);

        if (dlen) {
                count -= L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE;
                memcpy(skb_put(skb, count), data, count);
                data += count;
        }

        len -= skb->len;

        /* Continuation fragments (no L2CAP header) */
        frag = &skb_shinfo(skb)->frag_list;
        while (len) {
                count = min_t(unsigned int, conn->mtu, len);

                *frag = bt_skb_alloc(count, GFP_ATOMIC);
                if (!*frag)
                        goto fail;

                memcpy(skb_put(*frag, count), data, count);

                len  -= count;
                data += count;

                frag = &(*frag)->next;
        }

        return skb;

fail:
        kfree_skb(skb);
        return NULL;
}

static inline int l2cap_get_conf_opt(void **ptr, int *type, int *olen, unsigned long *val)
{
        struct l2cap_conf_opt *opt = *ptr;
        int len;

        len = L2CAP_CONF_OPT_SIZE + opt->len;
        *ptr += len;

        *type = opt->type;
        *olen = opt->len;

        switch (opt->len) {
        case 1:
                *val = *((u8 *) opt->val);
                break;

        case 2:
                *val = __le16_to_cpu(*((__le16 *) opt->val));
                break;

        case 4:
                *val = __le32_to_cpu(*((__le32 *) opt->val));
                break;

        default:
                *val = (unsigned long) opt->val;
                break;
        }

        BT_DBG("type 0x%2.2x len %d val 0x%lx", *type, opt->len, *val);
        return len;
}

static void l2cap_add_conf_opt(void **ptr, u8 type, u8 len, unsigned long val)
{
        struct l2cap_conf_opt *opt = *ptr;

        BT_DBG("type 0x%2.2x len %d val 0x%lx", type, len, val);

        opt->type = type;
        opt->len  = len;

        switch (len) {
        case 1:
                *((u8 *) opt->val)  = val;
                break;

        case 2:
                *((__le16 *) opt->val) = cpu_to_le16(val);
                break;

        case 4:
                *((__le32 *) opt->val) = cpu_to_le32(val);
                break;

        default:
                memcpy(opt->val, (void *) val, len);
                break;
        }

        *ptr += L2CAP_CONF_OPT_SIZE + len;
}

static int l2cap_build_conf_req(struct sock *sk, void *data)
{
        struct l2cap_pinfo *pi = l2cap_pi(sk);
        struct l2cap_conf_req *req = data;
        void *ptr = req->data;

        BT_DBG("sk %p", sk);

        if (pi->imtu != L2CAP_DEFAULT_MTU)
                l2cap_add_conf_opt(&ptr, L2CAP_CONF_MTU, 2, pi->imtu);

        /* FIXME: Need actual value of the flush timeout */
        //if (flush_to != L2CAP_DEFAULT_FLUSH_TO)
        //   l2cap_add_conf_opt(&ptr, L2CAP_CONF_FLUSH_TO, 2, pi->flush_to);

        req->dcid  = cpu_to_le16(pi->dcid);
        req->flags = cpu_to_le16(0);

        return ptr - data;
}

static int l2cap_parse_conf_req(struct sock *sk, void *data)
{
        struct l2cap_pinfo *pi = l2cap_pi(sk);
        struct l2cap_conf_rsp *rsp = data;
        void *ptr = rsp->data;
        void *req = pi->conf_req;
        int len = pi->conf_len;
        int type, hint, olen;
        unsigned long val;
        struct l2cap_conf_rfc rfc = { .mode = L2CAP_MODE_BASIC };
        u16 mtu = L2CAP_DEFAULT_MTU;
        u16 result = L2CAP_CONF_SUCCESS;

        BT_DBG("sk %p", sk);

        while (len >= L2CAP_CONF_OPT_SIZE) {
                len -= l2cap_get_conf_opt(&req, &type, &olen, &val);

                hint  = type & 0x80;
                type &= 0x7f;

                switch (type) {
                case L2CAP_CONF_MTU:
                        mtu = val;
                        break;

                case L2CAP_CONF_FLUSH_TO:
                        pi->flush_to = val;
                        break;

                case L2CAP_CONF_QOS:
                        break;

                case L2CAP_CONF_RFC:
                        if (olen == sizeof(rfc))
                                memcpy(&rfc, (void *) val, olen);
                        break;

                default:
                        if (hint)
                                break;

                        result = L2CAP_CONF_UNKNOWN;
                        *((u8 *) ptr++) = type;
                        break;
                }
        }

        if (result == L2CAP_CONF_SUCCESS) {
                /* Configure output options and let the other side know
                 * which ones we don't like. */

                if (rfc.mode == L2CAP_MODE_BASIC) {
                        if (mtu < pi->omtu)
                                result = L2CAP_CONF_UNACCEPT;
                        else {
                                pi->omtu = mtu;
                                pi->conf_state |= L2CAP_CONF_OUTPUT_DONE;
                        }

                        l2cap_add_conf_opt(&ptr, L2CAP_CONF_MTU, 2, pi->omtu);
                } else {
                        result = L2CAP_CONF_UNACCEPT;

                        memset(&rfc, 0, sizeof(rfc));
                        rfc.mode = L2CAP_MODE_BASIC;

                        l2cap_add_conf_opt(&ptr, L2CAP_CONF_RFC,
                                                sizeof(rfc), (unsigned long) &rfc);
                }
        }

        rsp->scid   = cpu_to_le16(pi->dcid);
        rsp->result = cpu_to_le16(result);
        rsp->flags  = cpu_to_le16(0x0000);

        return ptr - data;
}

static int l2cap_build_conf_rsp(struct sock *sk, void *data, u16 result, u16 flags)
{
        struct l2cap_conf_rsp *rsp = data;
        void *ptr = rsp->data;

        BT_DBG("sk %p", sk);

        rsp->scid   = cpu_to_le16(l2cap_pi(sk)->dcid);
        rsp->result = cpu_to_le16(result);
        rsp->flags  = cpu_to_le16(flags);

        return ptr - data;
}

static inline int l2cap_command_rej(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd, u8 *data)
{
        struct l2cap_cmd_rej *rej = (struct l2cap_cmd_rej *) data;

        if (rej->reason != 0x0000)
                return 0;

        if ((conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT) &&
                                        cmd->ident == conn->info_ident) {
                del_timer(&conn->info_timer);

                conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;
                conn->info_ident = 0;

                l2cap_conn_start(conn);
        }

        return 0;
}

static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd, u8 *data)
{
        struct l2cap_chan_list *list = &conn->chan_list;
        struct l2cap_conn_req *req = (struct l2cap_conn_req *) data;
        struct l2cap_conn_rsp rsp;
        struct sock *sk, *parent;
        int result, status = L2CAP_CS_NO_INFO;

        u16 dcid = 0, scid = __le16_to_cpu(req->scid);
        __le16 psm = req->psm;

        BT_DBG("psm 0x%2.2x scid 0x%4.4x", psm, scid);

        /* Check if we have socket listening on psm */
        parent = l2cap_get_sock_by_psm(BT_LISTEN, psm, conn->src);
        if (!parent) {
                result = L2CAP_CR_BAD_PSM;
                goto sendresp;
        }

        /* Check if the ACL is secure enough (if not SDP) */
        if (psm != cpu_to_le16(0x0001) &&
                                !hci_conn_check_link_mode(conn->hcon)) {
                conn->disc_reason = 0x05;
                result = L2CAP_CR_SEC_BLOCK;
                goto response;
        }

        result = L2CAP_CR_NO_MEM;

        /* Check for backlog size */
        if (sk_acceptq_is_full(parent)) {
                BT_DBG("backlog full %d", parent->sk_ack_backlog);
                goto response;
        }

        sk = l2cap_sock_alloc(sock_net(parent), NULL, BTPROTO_L2CAP, GFP_ATOMIC);
        if (!sk)
                goto response;

        write_lock_bh(&list->lock);

        /* Check if we already have channel with that dcid */
        if (__l2cap_get_chan_by_dcid(list, scid)) {
                write_unlock_bh(&list->lock);
                sock_set_flag(sk, SOCK_ZAPPED);
                l2cap_sock_kill(sk);
                goto response;
        }

        hci_conn_hold(conn->hcon);

        l2cap_sock_init(sk, parent);
        bacpy(&bt_sk(sk)->src, conn->src);
        bacpy(&bt_sk(sk)->dst, conn->dst);
        l2cap_pi(sk)->psm  = psm;
        l2cap_pi(sk)->dcid = scid;

        __l2cap_chan_add(conn, sk, parent);
        dcid = l2cap_pi(sk)->scid;

        l2cap_sock_set_timer(sk, sk->sk_sndtimeo);

        l2cap_pi(sk)->ident = cmd->ident;

        if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_DONE) {
                if (l2cap_check_security(sk)) {
                        if (bt_sk(sk)->defer_setup) {
                                sk->sk_state = BT_CONNECT2;
                                result = L2CAP_CR_PEND;
                                status = L2CAP_CS_AUTHOR_PEND;
                                parent->sk_data_ready(parent, 0);
                        } else {
                                sk->sk_state = BT_CONFIG;
                                result = L2CAP_CR_SUCCESS;
                                status = L2CAP_CS_NO_INFO;
                        }
                } else {
                        sk->sk_state = BT_CONNECT2;
                        result = L2CAP_CR_PEND;
                        status = L2CAP_CS_AUTHEN_PEND;
                }
        } else {
                sk->sk_state = BT_CONNECT2;
                result = L2CAP_CR_PEND;
                status = L2CAP_CS_NO_INFO;
        }

        write_unlock_bh(&list->lock);

response:
        bh_unlock_sock(parent);

sendresp:
        rsp.scid   = cpu_to_le16(scid);
        rsp.dcid   = cpu_to_le16(dcid);
        rsp.result = cpu_to_le16(result);
        rsp.status = cpu_to_le16(status);
        l2cap_send_cmd(conn, cmd->ident, L2CAP_CONN_RSP, sizeof(rsp), &rsp);

        if (result == L2CAP_CR_PEND && status == L2CAP_CS_NO_INFO) {
                struct l2cap_info_req info;
                info.type = cpu_to_le16(L2CAP_IT_FEAT_MASK);

                conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_SENT;
                conn->info_ident = l2cap_get_ident(conn);

                mod_timer(&conn->info_timer, jiffies +
                                        msecs_to_jiffies(L2CAP_INFO_TIMEOUT));

                l2cap_send_cmd(conn, conn->info_ident,
                                        L2CAP_INFO_REQ, sizeof(info), &info);
        }

        return 0;
}

static inline int l2cap_connect_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd, u8 *data)
{
        struct l2cap_conn_rsp *rsp = (struct l2cap_conn_rsp *) data;
        u16 scid, dcid, result, status;
        struct sock *sk;
        u8 req[128];

        scid   = __le16_to_cpu(rsp->scid);
        dcid   = __le16_to_cpu(rsp->dcid);
        result = __le16_to_cpu(rsp->result);
        status = __le16_to_cpu(rsp->status);

        BT_DBG("dcid 0x%4.4x scid 0x%4.4x result 0x%2.2x status 0x%2.2x", dcid, scid, result, status);

        if (scid) {
                if (!(sk = l2cap_get_chan_by_scid(&conn->chan_list, scid)))
                        return 0;
        } else {
                if (!(sk = l2cap_get_chan_by_ident(&conn->chan_list, cmd->ident)))
                        return 0;
        }

        switch (result) {
        case L2CAP_CR_SUCCESS:
                sk->sk_state = BT_CONFIG;
                l2cap_pi(sk)->ident = 0;
                l2cap_pi(sk)->dcid = dcid;
                l2cap_pi(sk)->conf_state |= L2CAP_CONF_REQ_SENT;

                l2cap_pi(sk)->conf_state &= ~L2CAP_CONF_CONNECT_PEND;

                l2cap_send_cmd(conn, l2cap_get_ident(conn), L2CAP_CONF_REQ,
                                        l2cap_build_conf_req(sk, req), req);
                break;

        case L2CAP_CR_PEND:
                l2cap_pi(sk)->conf_state |= L2CAP_CONF_CONNECT_PEND;
                break;

        default:
                l2cap_chan_del(sk, ECONNREFUSED);
                break;
        }

        bh_unlock_sock(sk);
        return 0;
}