l2cap.h

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/*
   BlueZ - Bluetooth protocol stack for Linux
   Copyright (C) 2000-2001 Qualcomm Incorporated
   Copyright (C) 2009-2010 Gustavo F. Padovan <[email protected]>
   Copyright (C) 2010 Google Inc.

   Written 2000,2001 by Maxim Krasnyansky <[email protected]>

   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.
*/

#ifndef __L2CAP_H
#define __L2CAP_H

#include <asm/unaligned.h>

/* L2CAP defaults */
#define L2CAP_DEFAULT_MTU       672
#define L2CAP_DEFAULT_MIN_MTU       48
#define L2CAP_DEFAULT_FLUSH_TO      0xffff
#define L2CAP_DEFAULT_TX_WINDOW     63
#define L2CAP_DEFAULT_EXT_WINDOW    0x3FFF
#define L2CAP_DEFAULT_MAX_TX        3
#define L2CAP_DEFAULT_RETRANS_TO    2000    /* 2 seconds */
#define L2CAP_DEFAULT_MONITOR_TO    12000   /* 12 seconds */
#define L2CAP_DEFAULT_MAX_PDU_SIZE  1009    /* Sized for 3-DH5 packet */
#define L2CAP_DEFAULT_ACK_TO        200
#define L2CAP_DEFAULT_MAX_SDU_SIZE  0xFFFF
#define L2CAP_DEFAULT_SDU_ITIME     0xFFFFFFFF
#define L2CAP_DEFAULT_ACC_LAT       0xFFFFFFFF
#define L2CAP_BREDR_MAX_PAYLOAD     1019    /* 3-DH5 packet */
#define L2CAP_LE_MIN_MTU        23

#define L2CAP_DISC_TIMEOUT      msecs_to_jiffies(100)
#define L2CAP_DISC_REJ_TIMEOUT      msecs_to_jiffies(5000)
#define L2CAP_ENC_TIMEOUT       msecs_to_jiffies(5000)
#define L2CAP_CONN_TIMEOUT      msecs_to_jiffies(40000)
#define L2CAP_INFO_TIMEOUT      msecs_to_jiffies(4000)

#define L2CAP_A2MP_DEFAULT_MTU      670

/* L2CAP socket address */
struct sockaddr_l2 {
    sa_family_t l2_family;
    __le16      l2_psm;
    bdaddr_t    l2_bdaddr;
    __le16      l2_cid;
    __u8        l2_bdaddr_type;
};

/* L2CAP socket options */
#define L2CAP_OPTIONS   0x01
struct l2cap_options {
    __u16 omtu;
    __u16 imtu;
    __u16 flush_to;
    __u8  mode;
    __u8  fcs;
    __u8  max_tx;
    __u16 txwin_size;
};

#define L2CAP_CONNINFO  0x02
struct l2cap_conninfo {
    __u16 hci_handle;
    __u8  dev_class[3];
};

#define L2CAP_LM    0x03
#define L2CAP_LM_MASTER     0x0001
#define L2CAP_LM_AUTH       0x0002
#define L2CAP_LM_ENCRYPT    0x0004
#define L2CAP_LM_TRUSTED    0x0008
#define L2CAP_LM_RELIABLE   0x0010
#define L2CAP_LM_SECURE     0x0020

/* L2CAP command codes */
#define L2CAP_COMMAND_REJ   0x01
#define L2CAP_CONN_REQ      0x02
#define L2CAP_CONN_RSP      0x03
#define L2CAP_CONF_REQ      0x04
#define L2CAP_CONF_RSP      0x05
#define L2CAP_DISCONN_REQ   0x06
#define L2CAP_DISCONN_RSP   0x07
#define L2CAP_ECHO_REQ      0x08
#define L2CAP_ECHO_RSP      0x09
#define L2CAP_INFO_REQ      0x0a
#define L2CAP_INFO_RSP      0x0b
#define L2CAP_CREATE_CHAN_REQ   0x0c
#define L2CAP_CREATE_CHAN_RSP   0x0d
#define L2CAP_MOVE_CHAN_REQ 0x0e
#define L2CAP_MOVE_CHAN_RSP 0x0f
#define L2CAP_MOVE_CHAN_CFM 0x10
#define L2CAP_MOVE_CHAN_CFM_RSP 0x11
#define L2CAP_CONN_PARAM_UPDATE_REQ 0x12
#define L2CAP_CONN_PARAM_UPDATE_RSP 0x13

/* L2CAP extended feature mask */
#define L2CAP_FEAT_FLOWCTL  0x00000001
#define L2CAP_FEAT_RETRANS  0x00000002
#define L2CAP_FEAT_BIDIR_QOS    0x00000004
#define L2CAP_FEAT_ERTM     0x00000008
#define L2CAP_FEAT_STREAMING    0x00000010
#define L2CAP_FEAT_FCS      0x00000020
#define L2CAP_FEAT_EXT_FLOW 0x00000040
#define L2CAP_FEAT_FIXED_CHAN   0x00000080
#define L2CAP_FEAT_EXT_WINDOW   0x00000100
#define L2CAP_FEAT_UCD      0x00000200

/* L2CAP checksum option */
#define L2CAP_FCS_NONE      0x00
#define L2CAP_FCS_CRC16     0x01

/* L2CAP fixed channels */
#define L2CAP_FC_L2CAP      0x02
#define L2CAP_FC_A2MP       0x08

/* L2CAP Control Field bit masks */
#define L2CAP_CTRL_SAR          0xC000
#define L2CAP_CTRL_REQSEQ       0x3F00
#define L2CAP_CTRL_TXSEQ        0x007E
#define L2CAP_CTRL_SUPERVISE        0x000C

#define L2CAP_CTRL_RETRANS      0x0080
#define L2CAP_CTRL_FINAL        0x0080
#define L2CAP_CTRL_POLL         0x0010
#define L2CAP_CTRL_FRAME_TYPE       0x0001 /* I- or S-Frame */

#define L2CAP_CTRL_TXSEQ_SHIFT      1
#define L2CAP_CTRL_SUPER_SHIFT      2
#define L2CAP_CTRL_POLL_SHIFT       4
#define L2CAP_CTRL_FINAL_SHIFT      7
#define L2CAP_CTRL_REQSEQ_SHIFT     8
#define L2CAP_CTRL_SAR_SHIFT        14

/* L2CAP Extended Control Field bit mask */
#define L2CAP_EXT_CTRL_TXSEQ        0xFFFC0000
#define L2CAP_EXT_CTRL_SAR      0x00030000
#define L2CAP_EXT_CTRL_SUPERVISE    0x00030000
#define L2CAP_EXT_CTRL_REQSEQ       0x0000FFFC

#define L2CAP_EXT_CTRL_POLL     0x00040000
#define L2CAP_EXT_CTRL_FINAL        0x00000002
#define L2CAP_EXT_CTRL_FRAME_TYPE   0x00000001 /* I- or S-Frame */

#define L2CAP_EXT_CTRL_FINAL_SHIFT  1
#define L2CAP_EXT_CTRL_REQSEQ_SHIFT 2
#define L2CAP_EXT_CTRL_SAR_SHIFT    16
#define L2CAP_EXT_CTRL_SUPER_SHIFT  16
#define L2CAP_EXT_CTRL_POLL_SHIFT   18
#define L2CAP_EXT_CTRL_TXSEQ_SHIFT  18

/* L2CAP Supervisory Function */
#define L2CAP_SUPER_RR      0x00
#define L2CAP_SUPER_REJ     0x01
#define L2CAP_SUPER_RNR     0x02
#define L2CAP_SUPER_SREJ    0x03

/* L2CAP Segmentation and Reassembly */
#define L2CAP_SAR_UNSEGMENTED   0x00
#define L2CAP_SAR_START     0x01
#define L2CAP_SAR_END       0x02
#define L2CAP_SAR_CONTINUE  0x03

/* L2CAP Command rej. reasons */
#define L2CAP_REJ_NOT_UNDERSTOOD    0x0000
#define L2CAP_REJ_MTU_EXCEEDED      0x0001
#define L2CAP_REJ_INVALID_CID       0x0002

/* L2CAP structures */
struct l2cap_hdr {
    __le16     len;
    __le16     cid;
} __packed;
#define L2CAP_HDR_SIZE      4
#define L2CAP_ENH_HDR_SIZE  6
#define L2CAP_EXT_HDR_SIZE  8

#define L2CAP_FCS_SIZE      2
#define L2CAP_SDULEN_SIZE   2
#define L2CAP_PSMLEN_SIZE   2
#define L2CAP_ENH_CTRL_SIZE 2
#define L2CAP_EXT_CTRL_SIZE 4

struct l2cap_cmd_hdr {
    __u8       code;
    __u8       ident;
    __le16     len;
} __packed;
#define L2CAP_CMD_HDR_SIZE  4

struct l2cap_cmd_rej_unk {
    __le16     reason;
} __packed;

struct l2cap_cmd_rej_mtu {
    __le16     reason;
    __le16     max_mtu;
} __packed;

struct l2cap_cmd_rej_cid {
    __le16     reason;
    __le16     scid;
    __le16     dcid;
} __packed;

struct l2cap_conn_req {
    __le16     psm;
    __le16     scid;
} __packed;

struct l2cap_conn_rsp {
    __le16     dcid;
    __le16     scid;
    __le16     result;
    __le16     status;
} __packed;

/* protocol/service multiplexer (PSM) */
#define L2CAP_PSM_SDP       0x0001
#define L2CAP_PSM_RFCOMM    0x0003

/* channel indentifier */
#define L2CAP_CID_SIGNALING 0x0001
#define L2CAP_CID_CONN_LESS 0x0002
#define L2CAP_CID_A2MP      0x0003
#define L2CAP_CID_LE_DATA   0x0004
#define L2CAP_CID_LE_SIGNALING  0x0005
#define L2CAP_CID_SMP       0x0006
#define L2CAP_CID_DYN_START 0x0040
#define L2CAP_CID_DYN_END   0xffff

/* connect/create channel results */
#define L2CAP_CR_SUCCESS    0x0000
#define L2CAP_CR_PEND       0x0001
#define L2CAP_CR_BAD_PSM    0x0002
#define L2CAP_CR_SEC_BLOCK  0x0003
#define L2CAP_CR_NO_MEM     0x0004
#define L2CAP_CR_BAD_AMP    0x0005

/* connect/create channel status */
#define L2CAP_CS_NO_INFO    0x0000
#define L2CAP_CS_AUTHEN_PEND    0x0001
#define L2CAP_CS_AUTHOR_PEND    0x0002

struct l2cap_conf_req {
    __le16     dcid;
    __le16     flags;
    __u8       data[0];
} __packed;

struct l2cap_conf_rsp {
    __le16     scid;
    __le16     flags;
    __le16     result;
    __u8       data[0];
} __packed;

#define L2CAP_CONF_SUCCESS  0x0000
#define L2CAP_CONF_UNACCEPT 0x0001
#define L2CAP_CONF_REJECT   0x0002
#define L2CAP_CONF_UNKNOWN  0x0003
#define L2CAP_CONF_PENDING  0x0004
#define L2CAP_CONF_EFS_REJECT   0x0005

/* configuration req/rsp continuation flag */
#define L2CAP_CONF_FLAG_CONTINUATION    0x0001

struct l2cap_conf_opt {
    __u8       type;
    __u8       len;
    __u8       val[0];
} __packed;
#define L2CAP_CONF_OPT_SIZE 2

#define L2CAP_CONF_HINT     0x80
#define L2CAP_CONF_MASK     0x7f

#define L2CAP_CONF_MTU      0x01
#define L2CAP_CONF_FLUSH_TO 0x02
#define L2CAP_CONF_QOS      0x03
#define L2CAP_CONF_RFC      0x04
#define L2CAP_CONF_FCS      0x05
#define L2CAP_CONF_EFS      0x06
#define L2CAP_CONF_EWS      0x07

#define L2CAP_CONF_MAX_SIZE 22

struct l2cap_conf_rfc {
    __u8       mode;
    __u8       txwin_size;
    __u8       max_transmit;
    __le16     retrans_timeout;
    __le16     monitor_timeout;
    __le16     max_pdu_size;
} __packed;

#define L2CAP_MODE_BASIC    0x00
#define L2CAP_MODE_RETRANS  0x01
#define L2CAP_MODE_FLOWCTL  0x02
#define L2CAP_MODE_ERTM     0x03
#define L2CAP_MODE_STREAMING    0x04

struct l2cap_conf_efs {
    __u8    id;
    __u8    stype;
    __le16  msdu;
    __le32  sdu_itime;
    __le32  acc_lat;
    __le32  flush_to;
} __packed;

#define L2CAP_SERV_NOTRAFIC 0x00
#define L2CAP_SERV_BESTEFFORT   0x01
#define L2CAP_SERV_GUARANTEED   0x02

#define L2CAP_BESTEFFORT_ID 0x01

struct l2cap_disconn_req {
    __le16     dcid;
    __le16     scid;
} __packed;

struct l2cap_disconn_rsp {
    __le16     dcid;
    __le16     scid;
} __packed;

struct l2cap_info_req {
    __le16      type;
} __packed;

struct l2cap_info_rsp {
    __le16      type;
    __le16      result;
    __u8        data[0];
} __packed;

struct l2cap_create_chan_req {
    __le16      psm;
    __le16      scid;
    __u8        amp_id;
} __packed;

struct l2cap_create_chan_rsp {
    __le16      dcid;
    __le16      scid;
    __le16      result;
    __le16      status;
} __packed;

struct l2cap_move_chan_req {
    __le16      icid;
    __u8        dest_amp_id;
} __packed;

struct l2cap_move_chan_rsp {
    __le16      icid;
    __le16      result;
} __packed;

#define L2CAP_MR_SUCCESS    0x0000
#define L2CAP_MR_PEND       0x0001
#define L2CAP_MR_BAD_ID     0x0002
#define L2CAP_MR_SAME_ID    0x0003
#define L2CAP_MR_NOT_SUPP   0x0004
#define L2CAP_MR_COLLISION  0x0005
#define L2CAP_MR_NOT_ALLOWED    0x0006

struct l2cap_move_chan_cfm {
    __le16      icid;
    __le16      result;
} __packed;

#define L2CAP_MC_CONFIRMED  0x0000
#define L2CAP_MC_UNCONFIRMED    0x0001

struct l2cap_move_chan_cfm_rsp {
    __le16      icid;
} __packed;

/* info type */
#define L2CAP_IT_CL_MTU     0x0001
#define L2CAP_IT_FEAT_MASK  0x0002
#define L2CAP_IT_FIXED_CHAN 0x0003

/* info result */
#define L2CAP_IR_SUCCESS    0x0000
#define L2CAP_IR_NOTSUPP    0x0001

struct l2cap_conn_param_update_req {
    __le16      min;
    __le16      max;
    __le16      latency;
    __le16      to_multiplier;
} __packed;

struct l2cap_conn_param_update_rsp {
    __le16      result;
} __packed;

/* Connection Parameters result */
#define L2CAP_CONN_PARAM_ACCEPTED   0x0000
#define L2CAP_CONN_PARAM_REJECTED   0x0001

/* ----- L2CAP channels and connections ----- */
struct l2cap_seq_list {
    __u16   head;
    __u16   tail;
    __u16   mask;
    __u16   *list;
};

#define L2CAP_SEQ_LIST_CLEAR    0xFFFF
#define L2CAP_SEQ_LIST_TAIL 0x8000

struct l2cap_chan {
    struct sock *sk;

    struct l2cap_conn   *conn;
    struct kref kref;

    __u8        state;

    __le16      psm;
    __u16       dcid;
    __u16       scid;

    __u16       imtu;
    __u16       omtu;
    __u16       flush_to;
    __u8        mode;
    __u8        chan_type;
    __u8        chan_policy;

    __le16      sport;

    __u8        sec_level;

    __u8        ident;

    __u8        conf_req[64];
    __u8        conf_len;
    __u8        num_conf_req;
    __u8        num_conf_rsp;

    __u8        fcs;

    __u16       tx_win;
    __u16       tx_win_max;
    __u16       ack_win;
    __u8        max_tx;
    __u16       retrans_timeout;
    __u16       monitor_timeout;
    __u16       mps;

    __u8        tx_state;
    __u8        rx_state;

    unsigned long   conf_state;
    unsigned long   conn_state;
    unsigned long   flags;

    __u16       next_tx_seq;
    __u16       expected_ack_seq;
    __u16       expected_tx_seq;
    __u16       buffer_seq;
    __u16       srej_save_reqseq;
    __u16       last_acked_seq;
    __u16       frames_sent;
    __u16       unacked_frames;
    __u8        retry_count;
    __u16       srej_queue_next;
    __u16       sdu_len;
    struct sk_buff  *sdu;
    struct sk_buff  *sdu_last_frag;

    __u16       remote_tx_win;
    __u8        remote_max_tx;
    __u16       remote_mps;

    __u8        local_id;
    __u8        local_stype;
    __u16       local_msdu;
    __u32       local_sdu_itime;
    __u32       local_acc_lat;
    __u32       local_flush_to;

    __u8        remote_id;
    __u8        remote_stype;
    __u16       remote_msdu;
    __u32       remote_sdu_itime;
    __u32       remote_acc_lat;
    __u32       remote_flush_to;

    struct delayed_work chan_timer;
    struct delayed_work retrans_timer;
    struct delayed_work monitor_timer;
    struct delayed_work ack_timer;

    struct sk_buff      *tx_send_head;
    struct sk_buff_head tx_q;
    struct sk_buff_head srej_q;
    struct l2cap_seq_list   srej_list;
    struct l2cap_seq_list   retrans_list;

    struct list_head    list;
    struct list_head    global_l;

    void            *data;
    struct l2cap_ops    *ops;
    struct mutex        lock;
};

struct l2cap_ops {
    char            *name;

    struct l2cap_chan   *(*new_connection) (struct l2cap_chan *chan);
    int         (*recv) (struct l2cap_chan * chan,
                     struct sk_buff *skb);
    void            (*teardown) (struct l2cap_chan *chan, int err);
    void            (*close) (struct l2cap_chan *chan);
    void            (*state_change) (struct l2cap_chan *chan,
                         int state);
    void            (*ready) (struct l2cap_chan *chan);
    struct sk_buff      *(*alloc_skb) (struct l2cap_chan *chan,
                           unsigned long len, int nb);
};

struct l2cap_conn {
    struct hci_conn     *hcon;
    struct hci_chan     *hchan;

    bdaddr_t        *dst;
    bdaddr_t        *src;

    unsigned int        mtu;

    __u32           feat_mask;
    __u8            fixed_chan_mask;

    __u8            info_state;
    __u8            info_ident;

    struct delayed_work info_timer;

    spinlock_t      lock;

    struct sk_buff      *rx_skb;
    __u32           rx_len;
    __u8            tx_ident;

    __u8            disc_reason;

    struct delayed_work security_timer;
    struct smp_chan     *smp_chan;

    struct list_head    chan_l;
    struct mutex        chan_lock;
};

#define L2CAP_INFO_CL_MTU_REQ_SENT  0x01
#define L2CAP_INFO_FEAT_MASK_REQ_SENT   0x04
#define L2CAP_INFO_FEAT_MASK_REQ_DONE   0x08

#define L2CAP_CHAN_RAW          1
#define L2CAP_CHAN_CONN_LESS        2
#define L2CAP_CHAN_CONN_ORIENTED    3
#define L2CAP_CHAN_CONN_FIX_A2MP    4

/* ----- L2CAP socket info ----- */
#define l2cap_pi(sk) ((struct l2cap_pinfo *) sk)

struct l2cap_pinfo {
    struct bt_sock      bt;
    struct l2cap_chan   *chan;
    struct sk_buff      *rx_busy_skb;
};

enum {
    CONF_REQ_SENT,
    CONF_INPUT_DONE,
    CONF_OUTPUT_DONE,
    CONF_MTU_DONE,
    CONF_MODE_DONE,
    CONF_CONNECT_PEND,
    CONF_NO_FCS_RECV,
    CONF_STATE2_DEVICE,
    CONF_EWS_RECV,
    CONF_LOC_CONF_PEND,
    CONF_REM_CONF_PEND,
    CONF_NOT_COMPLETE,
};

#define L2CAP_CONF_MAX_CONF_REQ 2
#define L2CAP_CONF_MAX_CONF_RSP 2

enum {
    CONN_SREJ_SENT,
    CONN_WAIT_F,
    CONN_SREJ_ACT,
    CONN_SEND_PBIT,
    CONN_REMOTE_BUSY,
    CONN_LOCAL_BUSY,
    CONN_REJ_ACT,
    CONN_SEND_FBIT,
    CONN_RNR_SENT,
};

/* Definitions for flags in l2cap_chan */
enum {
    FLAG_ROLE_SWITCH,
    FLAG_FORCE_ACTIVE,
    FLAG_FORCE_RELIABLE,
    FLAG_FLUSHABLE,
    FLAG_EXT_CTRL,
    FLAG_EFS_ENABLE,
};

enum {
    L2CAP_TX_STATE_XMIT,
    L2CAP_TX_STATE_WAIT_F,
};

enum {
    L2CAP_RX_STATE_RECV,
    L2CAP_RX_STATE_SREJ_SENT,
};

enum {
    L2CAP_TXSEQ_EXPECTED,
    L2CAP_TXSEQ_EXPECTED_SREJ,
    L2CAP_TXSEQ_UNEXPECTED,
    L2CAP_TXSEQ_UNEXPECTED_SREJ,
    L2CAP_TXSEQ_DUPLICATE,
    L2CAP_TXSEQ_DUPLICATE_SREJ,
    L2CAP_TXSEQ_INVALID,
    L2CAP_TXSEQ_INVALID_IGNORE,
};

enum {
    L2CAP_EV_DATA_REQUEST,
    L2CAP_EV_LOCAL_BUSY_DETECTED,
    L2CAP_EV_LOCAL_BUSY_CLEAR,
    L2CAP_EV_RECV_REQSEQ_AND_FBIT,
    L2CAP_EV_RECV_FBIT,
    L2CAP_EV_RETRANS_TO,
    L2CAP_EV_MONITOR_TO,
    L2CAP_EV_EXPLICIT_POLL,
    L2CAP_EV_RECV_IFRAME,
    L2CAP_EV_RECV_RR,
    L2CAP_EV_RECV_REJ,
    L2CAP_EV_RECV_RNR,
    L2CAP_EV_RECV_SREJ,
    L2CAP_EV_RECV_FRAME,
};

void l2cap_chan_hold(struct l2cap_chan *c);
void l2cap_chan_put(struct l2cap_chan *c);

static inline void l2cap_chan_lock(struct l2cap_chan *chan)
{
    mutex_lock(&chan->lock);
}

static inline void l2cap_chan_unlock(struct l2cap_chan *chan)
{
    mutex_unlock(&chan->lock);
}

static inline void l2cap_set_timer(struct l2cap_chan *chan,
                   struct delayed_work *work, long timeout)
{
    BT_DBG("chan %p state %s timeout %ld", chan,
           state_to_string(chan->state), timeout);

    /* If delayed work cancelled do not hold(chan)
       since it is already done with previous set_timer */
    if (!cancel_delayed_work(work))
        l2cap_chan_hold(chan);

    schedule_delayed_work(work, timeout);
}

static inline bool l2cap_clear_timer(struct l2cap_chan *chan,
                     struct delayed_work *work)
{
    bool ret;

    /* put(chan) if delayed work cancelled otherwise it
       is done in delayed work function */
    ret = cancel_delayed_work(work);
    if (ret)
        l2cap_chan_put(chan);

    return ret;
}

#define __set_chan_timer(c, t) l2cap_set_timer(c, &c->chan_timer, (t))
#define __clear_chan_timer(c) l2cap_clear_timer(c, &c->chan_timer)
#define __clear_retrans_timer(c) l2cap_clear_timer(c, &c->retrans_timer)
#define __clear_monitor_timer(c) l2cap_clear_timer(c, &c->monitor_timer)
#define __set_ack_timer(c) l2cap_set_timer(c, &chan->ack_timer, \
        msecs_to_jiffies(L2CAP_DEFAULT_ACK_TO));
#define __clear_ack_timer(c) l2cap_clear_timer(c, &c->ack_timer)

static inline int __seq_offset(struct l2cap_chan *chan, __u16 seq1, __u16 seq2)
{
    if (seq1 >= seq2)
        return seq1 - seq2;
    else
        return chan->tx_win_max + 1 - seq2 + seq1;
}

static inline __u16 __next_seq(struct l2cap_chan *chan, __u16 seq)
{
    return (seq + 1) % (chan->tx_win_max + 1);
}

static inline struct l2cap_chan *l2cap_chan_no_new_connection(struct l2cap_chan *chan)
{
    return NULL;
}

static inline void l2cap_chan_no_teardown(struct l2cap_chan *chan, int err)
{
}

static inline void l2cap_chan_no_ready(struct l2cap_chan *chan)
{
}

extern bool disable_ertm;

int l2cap_init_sockets(void);
void l2cap_cleanup_sockets(void);

void __l2cap_connect_rsp_defer(struct l2cap_chan *chan);
int __l2cap_wait_ack(struct sock *sk);

int l2cap_add_psm(struct l2cap_chan *chan, bdaddr_t *src, __le16 psm);
int l2cap_add_scid(struct l2cap_chan *chan,  __u16 scid);

struct l2cap_chan *l2cap_chan_create(void);
void l2cap_chan_close(struct l2cap_chan *chan, int reason);
int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid,
               bdaddr_t *dst, u8 dst_type);
int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len,
                                u32 priority);
void l2cap_chan_busy(struct l2cap_chan *chan, int busy);
int l2cap_chan_check_security(struct l2cap_chan *chan);
void l2cap_chan_set_defaults(struct l2cap_chan *chan);
int l2cap_ertm_init(struct l2cap_chan *chan);
void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan);
void l2cap_chan_del(struct l2cap_chan *chan, int err);

#endif /* __L2CAP_H */