ng_l2cap_misc.c

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/*
 * ng_l2cap_misc.c
 */
 
/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) Maksim Yevmenkin <m_evmenkin@yahoo.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Id: ng_l2cap_misc.c,v 1.5 2003/09/08 19:11:45 max Exp $
 * $FreeBSD$
 */
 
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/queue.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/bluetooth/include/ng_bluetooth.h>
#include <netgraph/bluetooth/include/ng_hci.h>
#include <netgraph/bluetooth/include/ng_l2cap.h>
#include <netgraph/bluetooth/l2cap/ng_l2cap_var.h>
#include <netgraph/bluetooth/l2cap/ng_l2cap_cmds.h>
#include <netgraph/bluetooth/l2cap/ng_l2cap_evnt.h>
#include <netgraph/bluetooth/l2cap/ng_l2cap_llpi.h>
#include <netgraph/bluetooth/l2cap/ng_l2cap_ulpi.h>
#include <netgraph/bluetooth/l2cap/ng_l2cap_misc.h>
 
static u_int16_t        ng_l2cap_get_cid        (ng_l2cap_p, int);
 
/******************************************************************************
 ******************************************************************************
 **                              Utility routines
 ******************************************************************************
 ******************************************************************************/
 
/*
 * Send hook information to the upper layer
 */
 
void
ng_l2cap_send_hook_info(node_p node, hook_p hook, void *arg1, int arg2)
{
        ng_l2cap_p       l2cap = NULL;
        struct ng_mesg  *msg = NULL;
        int              error = 0;
        ng_l2cap_node_hook_info_ep *ep ;
 
        if (node == NULL || NG_NODE_NOT_VALID(node) ||
            hook == NULL || NG_HOOK_NOT_VALID(hook))
                return;
 
        l2cap = (ng_l2cap_p) NG_NODE_PRIVATE(node);
        if (l2cap->hci == NULL || NG_HOOK_NOT_VALID(l2cap->hci) ||
            bcmp(&l2cap->bdaddr, NG_HCI_BDADDR_ANY, sizeof(l2cap->bdaddr)) == 0)
                return;
 
        NG_MKMESSAGE(msg, NGM_L2CAP_COOKIE, NGM_L2CAP_NODE_HOOK_INFO,
                     sizeof(*ep), M_NOWAIT);
 
        if (msg != NULL) {
                ep = (ng_l2cap_node_hook_info_ep *) &msg->data;
                bcopy(&l2cap->bdaddr, &ep->addr, sizeof(bdaddr_t));
                NG_SEND_MSG_HOOK(error, node, msg, hook, 0);
        } else
                error = ENOMEM;
 
        if (error != 0)
                NG_L2CAP_INFO(
"%s: %s - failed to send HOOK_INFO message to hook \"%s\", error=%d\n",
                        __func__, NG_NODE_NAME(l2cap->node), NG_HOOK_NAME(hook),
                        error);
} /* ng_l2cap_send_hook_info */
 
/*
 * Create new connection descriptor for the "remote" unit. 
 * Will link connection descriptor to the l2cap node.
 */
 
ng_l2cap_con_p
ng_l2cap_new_con(ng_l2cap_p l2cap, bdaddr_p bdaddr, int type)
{
        static int      fake_con_handle = 0x0f00;
        ng_l2cap_con_p  con = NULL;
 
        /* Create new connection descriptor */
        con = malloc(sizeof(*con), M_NETGRAPH_L2CAP,
                M_NOWAIT|M_ZERO);
        if (con == NULL)
                return (NULL);
 
        con->l2cap = l2cap;
        con->state = NG_L2CAP_CON_CLOSED;
        con->encryption = 0;
        /*
         * XXX
         *
         * Assign fake connection handle to the connection descriptor.
         * Bluetooth specification marks 0x0f00 - 0x0fff connection 
         * handles as reserved. We need this fake connection handles 
         * for timeouts. Connection handle will be passed as argument
         * to timeout so when timeout happens we can find the right
         * connection descriptor. We can not pass pointers, because
         * timeouts are external (to Netgraph) events and there might
         * be a race when node/hook goes down and timeout event already
         * went into node's queue
         */
 
        con->con_handle = fake_con_handle ++;
        if (fake_con_handle > 0x0fff)
                fake_con_handle = 0x0f00;
 
        bcopy(bdaddr, &con->remote, sizeof(con->remote));
        con->linktype = type;
        ng_callout_init(&con->con_timo);
 
        con->ident = NG_L2CAP_FIRST_IDENT - 1;
        TAILQ_INIT(&con->cmd_list);
 
        /* Link connection */
        LIST_INSERT_HEAD(&l2cap->con_list, con, next); 
 
        return (con);
} /* ng_l2cap_new_con */
 
/*
 * Add reference to the connection descriptor
 */
 
void
ng_l2cap_con_ref(ng_l2cap_con_p con)
{
        con->refcnt ++;
 
        if (con->flags & NG_L2CAP_CON_AUTO_DISCON_TIMO) {
                if ((con->state != NG_L2CAP_CON_OPEN) ||
                    (con->flags & NG_L2CAP_CON_OUTGOING) == 0)
                        panic(
"%s: %s - bad auto disconnect timeout, state=%d, flags=%#x\n",
                                __func__, NG_NODE_NAME(con->l2cap->node),
                                con->state, con->flags);
 
                ng_l2cap_discon_untimeout(con);
        }
} /* ng_l2cap_con_ref */
 
/*
 * Remove reference from the connection descriptor
 */
 
void
ng_l2cap_con_unref(ng_l2cap_con_p con)
{
        con->refcnt --;
 
        if (con->refcnt < 0)
                panic(
"%s: %s - con->refcnt < 0\n", __func__, NG_NODE_NAME(con->l2cap->node));
 
        /*
         * Set auto disconnect timer only if the following conditions are met:
         * 1) we have no reference on the connection
         * 2) connection is in OPEN state
         * 3) it is an outgoing connection
         * 4) disconnect timeout > 0
         * 5) connection is not dying
         */
 
        if ((con->refcnt == 0) &&
            (con->state == NG_L2CAP_CON_OPEN) &&
            (con->flags & NG_L2CAP_CON_OUTGOING) && 
            (con->l2cap->discon_timo > 0) &&
            ((con->flags & NG_L2CAP_CON_DYING) == 0))
                ng_l2cap_discon_timeout(con);
} /* ng_l2cap_con_unref */
 
/*
 * Set auto disconnect timeout
 * XXX FIXME: check return code from ng_callout
 */
 
int
ng_l2cap_discon_timeout(ng_l2cap_con_p con)
{
        if (con->flags & (NG_L2CAP_CON_LP_TIMO|NG_L2CAP_CON_AUTO_DISCON_TIMO))
                panic(
"%s: %s - invalid timeout, state=%d, flags=%#x\n",
                        __func__, NG_NODE_NAME(con->l2cap->node),
                        con->state, con->flags);
 
        con->flags |= NG_L2CAP_CON_AUTO_DISCON_TIMO;
        ng_callout(&con->con_timo, con->l2cap->node, NULL,
                                con->l2cap->discon_timo * hz,
                                ng_l2cap_process_discon_timeout, NULL,
                                con->con_handle);
 
        return (0);
} /* ng_l2cap_discon_timeout */
 
/*
 * Unset auto disconnect timeout
 */
 
int
ng_l2cap_discon_untimeout(ng_l2cap_con_p con)
{
        if (!(con->flags & NG_L2CAP_CON_AUTO_DISCON_TIMO))
                panic(
"%s: %s - no disconnect timeout, state=%d, flags=%#x\n",
                        __func__,  NG_NODE_NAME(con->l2cap->node),
                        con->state, con->flags);
 
        if (ng_uncallout(&con->con_timo, con->l2cap->node) < 1)
                return (ETIMEDOUT);
 
        con->flags &= ~NG_L2CAP_CON_AUTO_DISCON_TIMO;
 
        return (0);
} /* ng_l2cap_discon_untimeout */
 
/*
 * Free connection descriptor. Will unlink connection and free everything.
 */
 
void
ng_l2cap_free_con(ng_l2cap_con_p con)
{
        ng_l2cap_chan_p f = NULL, n = NULL;
 
        con->state = NG_L2CAP_CON_CLOSED;
 
        while (con->tx_pkt != NULL) {
                struct mbuf     *m = con->tx_pkt->m_nextpkt;
 
                m_freem(con->tx_pkt);
                con->tx_pkt = m;
        }
 
        NG_FREE_M(con->rx_pkt);
 
        for (f = LIST_FIRST(&con->l2cap->chan_list); f != NULL; ) {
                n = LIST_NEXT(f, next);
 
                if (f->con == con)
                        ng_l2cap_free_chan(f);
 
                f = n;
        }
 
        while (!TAILQ_EMPTY(&con->cmd_list)) {
                ng_l2cap_cmd_p  cmd = TAILQ_FIRST(&con->cmd_list);
 
                ng_l2cap_unlink_cmd(cmd);
                if (cmd->flags & NG_L2CAP_CMD_PENDING)
                        ng_l2cap_command_untimeout(cmd);
                ng_l2cap_free_cmd(cmd);
        }
 
        if (con->flags & (NG_L2CAP_CON_AUTO_DISCON_TIMO|NG_L2CAP_CON_LP_TIMO))
                panic(
"%s: %s - timeout pending! state=%d, flags=%#x\n",
                        __func__,  NG_NODE_NAME(con->l2cap->node),
                        con->state, con->flags);
 
        LIST_REMOVE(con, next);
 
        bzero(con, sizeof(*con));
        free(con, M_NETGRAPH_L2CAP);
} /* ng_l2cap_free_con */
 
/*
 * Get connection by "remote" address
 */
 
ng_l2cap_con_p
ng_l2cap_con_by_addr(ng_l2cap_p l2cap, bdaddr_p bdaddr, unsigned int type)
{
        ng_l2cap_con_p  con = NULL;
 
        LIST_FOREACH(con, &l2cap->con_list, next)
                if ((bcmp(bdaddr, &con->remote, sizeof(con->remote)) == 0)&&
                    (con->linktype == type))
                        break;
 
        return (con);
} /* ng_l2cap_con_by_addr */
 
/*
 * Get connection by "handle" 
 */
 
ng_l2cap_con_p
ng_l2cap_con_by_handle(ng_l2cap_p l2cap, u_int16_t con_handle)
{
        ng_l2cap_con_p  con = NULL;
 
        LIST_FOREACH(con, &l2cap->con_list, next)
                if (con->con_handle == con_handle)
                        break;
 
        return (con);
} /* ng_l2cap_con_by_handle */
 
/*
 * Allocate new L2CAP channel descriptor on "con" connection with "psm".
 * Will link the channel to the l2cap node
 */
 
ng_l2cap_chan_p
ng_l2cap_new_chan(ng_l2cap_p l2cap, ng_l2cap_con_p con, u_int16_t psm, int idtype)
{
        ng_l2cap_chan_p ch = NULL;
 
        ch = malloc(sizeof(*ch), M_NETGRAPH_L2CAP,
                M_NOWAIT|M_ZERO);
        if (ch == NULL)
                return (NULL);
        if(idtype == NG_L2CAP_L2CA_IDTYPE_ATT){
                ch->scid = ch->dcid = NG_L2CAP_ATT_CID;
        }else if(idtype == NG_L2CAP_L2CA_IDTYPE_SMP){
                ch->scid = ch->dcid = NG_L2CAP_SMP_CID;
        }else{
                ch->scid = ng_l2cap_get_cid(l2cap,
                                            (con->linktype!= NG_HCI_LINK_ACL));
        }
 
        ch->idtype = idtype;
        if (ch->scid != NG_L2CAP_NULL_CID) {
                /* Initialize channel */
                ch->psm = psm;
                ch->con = con;
                ch->state = NG_L2CAP_CLOSED;
 
                /* Set MTU and flow control settings to defaults */
                ch->imtu = NG_L2CAP_MTU_DEFAULT;
                bcopy(ng_l2cap_default_flow(), &ch->iflow, sizeof(ch->iflow));
 
                ch->omtu = NG_L2CAP_MTU_DEFAULT;
                bcopy(ng_l2cap_default_flow(), &ch->oflow, sizeof(ch->oflow));
 
                ch->flush_timo = NG_L2CAP_FLUSH_TIMO_DEFAULT;
                ch->link_timo = NG_L2CAP_LINK_TIMO_DEFAULT;
 
                LIST_INSERT_HEAD(&l2cap->chan_list, ch, next);
 
                ng_l2cap_con_ref(con);
        } else {
                bzero(ch, sizeof(*ch));
                free(ch, M_NETGRAPH_L2CAP);
                ch = NULL;
        }
 
        return (ch);
} /* ng_l2cap_new_chan */
 
ng_l2cap_chan_p
ng_l2cap_chan_by_scid(ng_l2cap_p l2cap, u_int16_t scid, int idtype)
{
        ng_l2cap_chan_p ch = NULL;
 
        if((idtype == NG_L2CAP_L2CA_IDTYPE_ATT)||
           (idtype == NG_L2CAP_L2CA_IDTYPE_SMP)){
                return NULL;
        }
 
        LIST_FOREACH(ch, &l2cap->chan_list, next){
                if((idtype != NG_L2CAP_L2CA_IDTYPE_BREDR)&&
                   (ch->con->linktype == NG_HCI_LINK_ACL ))
                        continue;
                if((idtype != NG_L2CAP_L2CA_IDTYPE_LE)&&
                   (ch->con->linktype != NG_HCI_LINK_ACL ))
                        continue;
                if (ch->scid == scid)
                        break;
        }
        return (ch);
} /* ng_l2cap_chan_by_scid */
 
ng_l2cap_chan_p
ng_l2cap_chan_by_conhandle(ng_l2cap_p l2cap, uint16_t scid,
                           u_int16_t con_handle)
{
        ng_l2cap_chan_p ch = NULL;
 
        LIST_FOREACH(ch, &l2cap->chan_list, next){
                if ((ch->scid == scid) &&
                    (ch->con->con_handle == con_handle))
                        break;
        }
        return (ch);
} /* ng_l2cap_chan_by_scid */
 
/*
 * Free channel descriptor.
 */
 
void
ng_l2cap_free_chan(ng_l2cap_chan_p ch)
{
        ng_l2cap_cmd_p  f = NULL, n = NULL;
 
        f = TAILQ_FIRST(&ch->con->cmd_list);
 
        while (f != NULL) {
                n = TAILQ_NEXT(f, next);
 
                if (f->ch == ch) {
                        ng_l2cap_unlink_cmd(f);
                        if (f->flags & NG_L2CAP_CMD_PENDING)
                                ng_l2cap_command_untimeout(f);
                        ng_l2cap_free_cmd(f);
                }
 
                f = n;
        }
 
        LIST_REMOVE(ch, next);
 
        ng_l2cap_con_unref(ch->con);
 
        bzero(ch, sizeof(*ch));
        free(ch, M_NETGRAPH_L2CAP);
} /* ng_l2cap_free_chan */
 
/*
 * Create new L2CAP command descriptor. WILL NOT add command to the queue.
 */
 
ng_l2cap_cmd_p
ng_l2cap_new_cmd(ng_l2cap_con_p con, ng_l2cap_chan_p ch, u_int8_t ident,
                u_int8_t code, u_int32_t token)
{
        ng_l2cap_cmd_p  cmd = NULL;
 
        KASSERT((ch == NULL || ch->con == con),
("%s: %s - invalid channel pointer!\n",
                __func__, NG_NODE_NAME(con->l2cap->node)));
 
        cmd = malloc(sizeof(*cmd), M_NETGRAPH_L2CAP,
                M_NOWAIT|M_ZERO);
        if (cmd == NULL)
                return (NULL);
 
        cmd->con = con;
        cmd->ch = ch;
        cmd->ident = ident;
        cmd->code = code;
        cmd->token = token;
        ng_callout_init(&cmd->timo);
 
        return (cmd);
} /* ng_l2cap_new_cmd */
 
/*
 * Get pending (i.e. initiated by local side) L2CAP command descriptor by ident
 */
 
ng_l2cap_cmd_p
ng_l2cap_cmd_by_ident(ng_l2cap_con_p con, u_int8_t ident)
{
        ng_l2cap_cmd_p  cmd = NULL;
 
        TAILQ_FOREACH(cmd, &con->cmd_list, next) {
                if ((cmd->flags & NG_L2CAP_CMD_PENDING) && cmd->ident == ident) {
                        KASSERT((cmd->con == con),
("%s: %s - invalid connection pointer!\n",
                                __func__, NG_NODE_NAME(con->l2cap->node)));
 
                        break;
                }
        }
 
        return (cmd);
} /* ng_l2cap_cmd_by_ident */
 
/*
 * Set LP timeout
 * XXX FIXME: check return code from ng_callout
 */
 
int
ng_l2cap_lp_timeout(ng_l2cap_con_p con)
{
        if (con->flags & (NG_L2CAP_CON_LP_TIMO|NG_L2CAP_CON_AUTO_DISCON_TIMO))
                panic(
"%s: %s - invalid timeout, state=%d, flags=%#x\n",
                        __func__, NG_NODE_NAME(con->l2cap->node),
                        con->state, con->flags);
 
        con->flags |= NG_L2CAP_CON_LP_TIMO;
        ng_callout(&con->con_timo, con->l2cap->node, NULL,
                                bluetooth_hci_connect_timeout(),
                                ng_l2cap_process_lp_timeout, NULL,
                                con->con_handle);
 
        return (0);
} /* ng_l2cap_lp_timeout */
 
/*
 * Unset LP timeout
 */
 
int
ng_l2cap_lp_untimeout(ng_l2cap_con_p con)
{
        if (!(con->flags & NG_L2CAP_CON_LP_TIMO))
                panic(
"%s: %s - no LP connection timeout, state=%d, flags=%#x\n",
                        __func__,  NG_NODE_NAME(con->l2cap->node),
                        con->state, con->flags);
 
        if (ng_uncallout(&con->con_timo, con->l2cap->node) < 1)
                return (ETIMEDOUT);
 
        con->flags &= ~NG_L2CAP_CON_LP_TIMO;
 
        return (0);
} /* ng_l2cap_lp_untimeout */
 
/*
 * Set L2CAP command timeout
 * XXX FIXME: check return code from ng_callout
 */
 
int
ng_l2cap_command_timeout(ng_l2cap_cmd_p cmd, int timo)
{
        int     arg;
 
        if (cmd->flags & NG_L2CAP_CMD_PENDING)
                panic(
"%s: %s - duplicated command timeout, code=%#x, flags=%#x\n",
                        __func__, NG_NODE_NAME(cmd->con->l2cap->node),
                        cmd->code, cmd->flags);
 
        arg = ((cmd->ident << 16) | cmd->con->con_handle);
        cmd->flags |= NG_L2CAP_CMD_PENDING;
        ng_callout(&cmd->timo, cmd->con->l2cap->node, NULL, timo,
                                ng_l2cap_process_command_timeout, NULL, arg);
 
        return (0);
} /* ng_l2cap_command_timeout */
 
/*
 * Unset L2CAP command timeout
 */
 
int
ng_l2cap_command_untimeout(ng_l2cap_cmd_p cmd)
{
        if (!(cmd->flags & NG_L2CAP_CMD_PENDING))
                panic(
"%s: %s - no command timeout, code=%#x, flags=%#x\n",
                        __func__, NG_NODE_NAME(cmd->con->l2cap->node),
                        cmd->code, cmd->flags);
 
        if (ng_uncallout(&cmd->timo, cmd->con->l2cap->node) < 1)
                return (ETIMEDOUT);
 
        cmd->flags &= ~NG_L2CAP_CMD_PENDING;
 
        return (0);
} /* ng_l2cap_command_untimeout */
 
/*
 * Prepend "m"buf with "size" bytes
 */
 
struct mbuf *
ng_l2cap_prepend(struct mbuf *m, int size)
{
        M_PREPEND(m, size, M_NOWAIT);
        if (m == NULL || (m->m_len < size && (m = m_pullup(m, size)) == NULL))
                return (NULL);
 
        return (m);
} /* ng_l2cap_prepend */
 
/*
 * Default flow settings
 */
 
ng_l2cap_flow_p
ng_l2cap_default_flow(void)
{
        static ng_l2cap_flow_t  default_flow = {
                /* flags */             0x0,
                /* service_type */      NG_HCI_SERVICE_TYPE_BEST_EFFORT,
                /* token_rate */        0xffffffff, /* maximum */
                /* token_bucket_size */ 0xffffffff, /* maximum */
                /* peak_bandwidth */    0x00000000, /* maximum */
                /* latency */           0xffffffff, /* don't care */
                /* delay_variation */   0xffffffff  /* don't care */
        };
 
        return (&default_flow);
} /* ng_l2cap_default_flow */
 
/*
 * Get next available channel ID
 * XXX FIXME this is *UGLY* but will do for now
 */
 
static u_int16_t
ng_l2cap_get_cid(ng_l2cap_p l2cap,int isle)
{
        u_int16_t       cid ;
        u_int16_t       endcid;
        uint16_t         mask;
        int idtype;
        if(isle){
                endcid = l2cap->lecid;
                /*Assume Last CID is 2^n-1 */
                mask = NG_L2CAP_LELAST_CID;
                idtype = NG_L2CAP_L2CA_IDTYPE_LE;
        }else{
                endcid = l2cap->cid;
                /*Assume Last CID is 2^n-1 */           
                mask = NG_L2CAP_LAST_CID;
                idtype = NG_L2CAP_L2CA_IDTYPE_BREDR;
        }
        cid = (endcid+1) & mask;
             
        if (cid < NG_L2CAP_FIRST_CID)
                cid = NG_L2CAP_FIRST_CID;
 
        while (cid != endcid) {
                if (ng_l2cap_chan_by_scid(l2cap, cid, idtype) == NULL) {
                        if(!isle){
                                l2cap->cid = cid;
                        }else{
                                l2cap->lecid = cid;
                        }
                        return (cid);
                }
 
                cid ++;
                cid &= mask;
                if (cid < NG_L2CAP_FIRST_CID)
                        cid = NG_L2CAP_FIRST_CID;
        }
                
        return (NG_L2CAP_NULL_CID);
} /* ng_l2cap_get_cid */
 
/*
 * Get next available command ident
 * XXX FIXME this is *UGLY* but will do for now
 */
 
u_int8_t
ng_l2cap_get_ident(ng_l2cap_con_p con)
{
        u_int8_t        ident = con->ident + 1;
 
        if (ident < NG_L2CAP_FIRST_IDENT)
                ident = NG_L2CAP_FIRST_IDENT;
 
        while (ident != con->ident) {
                if (ng_l2cap_cmd_by_ident(con, ident) == NULL) {
                        con->ident = ident;
 
                        return (ident);
                }
 
                ident ++;
                if (ident < NG_L2CAP_FIRST_IDENT)
                        ident = NG_L2CAP_FIRST_IDENT;
        }
 
        return (NG_L2CAP_NULL_IDENT);
} /* ng_l2cap_get_ident */