freebsd-dev/sys/i4b/layer3/i4b_l2if.c

/*
 * Copyright (c) 1997, 2002 Hellmuth Michaelis. 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.
 *
 *---------------------------------------------------------------------------
 *
 *	i4b_l2if.c - Layer 3 interface to Layer 2
 *	-------------------------------------------
 *      last edit-date: [Sun Aug 11 12:48:41 2002]
 *
 *---------------------------------------------------------------------------*/

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>

#include <machine/i4b_debug.h>
#include <machine/i4b_ioctl.h>
#include <machine/i4b_cause.h>

#include <i4b/include/i4b_isdnq931.h>
#include <i4b/include/i4b_l2l3.h>
#include <i4b/include/i4b_l3l4.h>
#include <i4b/include/i4b_mbuf.h>

#include <i4b/layer3/i4b_l3.h>
#include <i4b/layer3/i4b_l3fsm.h>
#include <i4b/layer3/i4b_q931.h>


static unsigned char make_q931_cause(cause_t cause);

/*---------------------------------------------------------------------------*
 * this converts our internal state (number) to the number specified
 * in Q.931 and is used for reporting our state in STATUS messages.
 *---------------------------------------------------------------------------*/
int i4b_status_tab[] = {
	0,	/*	ST_U0,	*/
	1,	/*	ST_U1,	*/
	3,	/*	ST_U3,	*/
	4,	/*	ST_U4,	*/
	6,	/*	ST_U6,	*/
	7,	/*	ST_U7,	*/
	8,	/*	ST_U8,	*/
	9,	/*	ST_U9,	*/
	10,	/*	ST_U10,	*/
	11,	/*	ST_U11,	*/
	12,	/*	ST_U12,	*/
	19,	/*	ST_U19,	*/
	6,	/*	ST_IWA,	*/
	6,	/*	ST_IWR,	*/
	1,	/*	ST_OW,	*/
	6,	/*	ST_IWL,	*/	
};

/*---------------------------------------------------------------------------*
 *	return a valid q.931/q.850 cause from any of the internal causes
 *---------------------------------------------------------------------------*/
static unsigned char
make_q931_cause(cause_t cause)
{
	register unsigned char ret;
	
	switch(GET_CAUSE_TYPE(cause))
	{
		case CAUSET_Q850:
			ret = GET_CAUSE_VAL(cause);
			break;
		case CAUSET_I4B:
			ret = cause_tab_q931[GET_CAUSE_VAL(cause)];
			break;
		default:
			panic("make_q931_cause: unknown cause type!");
			break;
	}
	ret |= EXT_LAST;
	return(ret);
}

/*---------------------------------------------------------------------------*
 *	return status of data link
 *---------------------------------------------------------------------------*/
int
i4b_get_dl_stat(call_desc_t *cd)
{
	return(ctrl_desc[cd->controller].dl_est);
}

/*---------------------------------------------------------------------------*
 *	DL ESTABLISH INDICATION from Layer 2
 *---------------------------------------------------------------------------*/
int
i4b_dl_establish_ind(int unit)
{
	int i;
	int found = 0;
	
	NDBGL2(L2_PRIM, "DL-ESTABLISH-IND unit %d",unit);

	/* first set DL up in controller descriptor */
	
	for(i=0; i < nctrl; i++)
	{
		if((ctrl_desc[i].ctrl_type == CTRL_PASSIVE) &&
		   (ctrl_desc[i].unit == unit))
                {
                 	NDBGL3(L3_MSG, "unit=%d DL established!",unit);
			ctrl_desc[i].dl_est = DL_UP;
			found = 1;
		}
	}

	if(found == 0)
	{
	       	NDBGL3(L3_ERR, "ERROR, controller not found for unit=%d!",unit);
		return(-1);	       	
	}

	found = 0;

	/* second, inform all (!) active call of the event */
	
	for(i=0; i < N_CALL_DESC; i++)
	{
		if( (call_desc[i].cdid != 0) &&
		    (ctrl_desc[call_desc[i].controller].ctrl_type == CTRL_PASSIVE) &&
		    (ctrl_desc[call_desc[i].controller].unit == unit))
                {
                 	NDBGL3(L3_MSG, "unit=%d, index=%d cdid=%u cr=%d",
					unit, i, call_desc[i].cdid, call_desc[i].cr);
			next_l3state(&call_desc[i], EV_DLESTIN);
			found++;
		}
	}
	
	if(found == 0)
	{
		NDBGL3(L3_ERR, "ERROR, no cdid for unit %d found!", unit);
		return(-1);
	}
	else
	{
		return(0);
	}
}

/*---------------------------------------------------------------------------*
 *	DL ESTABLISH CONFIRM from Layer 2
 *---------------------------------------------------------------------------*/
int
i4b_dl_establish_cnf(int unit)
{
	int i;
	int found = 0;

	NDBGL2(L2_PRIM, "DL-ESTABLISH-CONF unit %d",unit);
	
	for(i=0; i < N_CALL_DESC; i++)
	{
		if( (call_desc[i].cdid != 0) &&
		    (ctrl_desc[call_desc[i].controller].ctrl_type == CTRL_PASSIVE) &&
		    (ctrl_desc[call_desc[i].controller].unit == unit))
                {
			ctrl_desc[call_desc[i].controller].dl_est = DL_UP;

                 	NDBGL3(L3_MSG, "unit=%d, index=%d cdid=%u cr=%d",
					unit, i, call_desc[i].cdid, call_desc[i].cr);

			next_l3state(&call_desc[i], EV_DLESTCF);
			found++;
		}
	}
	
	if(found == 0)
	{
		NDBGL3(L3_ERR, "ERROR, no cdid for unit %d found!", unit);
		return(-1);
	}
	else
	{
		return(0);
	}
}

/*---------------------------------------------------------------------------*
 *	DL RELEASE INDICATION from Layer 2
 *---------------------------------------------------------------------------*/
int
i4b_dl_release_ind(int unit)
{
	int i;
	int found = 0;

	NDBGL2(L2_PRIM, "DL-RELEASE-IND unit %d",unit);
	
	/* first set controller to down */
	
	for(i=0; i < nctrl; i++)
	{
		if((ctrl_desc[i].ctrl_type == CTRL_PASSIVE) &&
		   (ctrl_desc[i].unit == unit))
                {
                 	NDBGL3(L3_MSG, "unit=%d DL released!",unit);
			ctrl_desc[i].dl_est = DL_DOWN;
			found = 1;
		}
	}

	if(found == 0)
	{
	       	NDBGL3(L3_ERR, "ERROR, controller not found for unit=%d!",unit);
		return(-1);
	}
	
	found = 0;

	/* second, inform all (!) active calls of the event */
	
	for(i=0; i < N_CALL_DESC; i++)
	{
		if( (call_desc[i].cdid != 0) &&
		    (ctrl_desc[call_desc[i].controller].ctrl_type == CTRL_PASSIVE) &&
		    (ctrl_desc[call_desc[i].controller].unit == unit))
                {
                 	NDBGL3(L3_MSG, "unit=%d, index=%d cdid=%u cr=%d",
					unit, i, call_desc[i].cdid, call_desc[i].cr);
			next_l3state(&call_desc[i], EV_DLRELIN);
			found++;
		}
	}
	
	if(found == 0)
	{
		/* this is not an error since it might be a normal call end */
		NDBGL3(L3_MSG, "no cdid for unit %d found", unit);
	}
	return(0);
}

/*---------------------------------------------------------------------------*
 *	DL RELEASE CONFIRM from Layer 2
 *---------------------------------------------------------------------------*/
int
i4b_dl_release_cnf(int unit)
{
	int i;
	
	NDBGL2(L2_PRIM, "DL-RELEASE-CONF unit %d",unit);
	
	for(i=0; i < nctrl; i++)
	{
		if((ctrl_desc[i].ctrl_type == CTRL_PASSIVE) &&
		   (ctrl_desc[i].unit == unit))
                {
                 	NDBGL3(L3_MSG, "unit=%d DL released!",unit);
			ctrl_desc[i].dl_est = DL_DOWN;
			return(0);
		}
	}
       	NDBGL3(L3_ERR, "ERROR, controller not found for unit=%d!",unit);
	return(-1);
}

/*---------------------------------------------------------------------------*
 *	i4b_dl_data_ind - process a rx'd I-frame got from layer 2
 *---------------------------------------------------------------------------*/
int
i4b_dl_data_ind(int unit, struct mbuf *m)
{
#ifdef NOTDEF
	NDBGL2(L2_PRIM, "DL-DATA-IND unit %d",unit);
#endif
	i4b_decode_q931(unit, m->m_len, m->m_data);
	i4b_Dfreembuf(m);
	return(0);
}

/*---------------------------------------------------------------------------*
 *	dl_unit_data_ind - process a rx'd U-frame got from layer 2
 *---------------------------------------------------------------------------*/
int
i4b_dl_unit_data_ind(int unit, struct mbuf *m)
{
#ifdef NOTDEF
	NDBGL2(L2_PRIM, "DL-UNIT-DATA-IND unit %d",unit);
#endif
	i4b_decode_q931(unit, m->m_len, m->m_data);
	i4b_Dfreembuf(m);
	return(0);
}

/*---------------------------------------------------------------------------*
 *	send CONNECT message
 *---------------------------------------------------------------------------*/
void
i4b_l3_tx_connect(call_desc_t *cd)
{
	struct mbuf *m;
	u_char *ptr;

	NDBGL3(L3_PRIM, "unit %d, cr = 0x%02x", ctrl_desc[cd->controller].unit, cd->cr);
	
	if((m = i4b_Dgetmbuf(I_FRAME_HDRLEN + MSG_CONNECT_LEN)) == NULL)
		panic("i4b_l3_tx_connect: can't allocate mbuf\n");

	ptr = m->m_data + I_FRAME_HDRLEN;
	
	*ptr++ = PD_Q931;		/* protocol discriminator */
	*ptr++ = 0x01;			/* call reference length */
	*ptr++ = setup_cr(cd, cd->cr);	/* call reference value */
	*ptr++ = CONNECT;		/* message type = connect */
	
	DL_Data_Req(ctrl_desc[cd->controller].unit, m);
}

/*---------------------------------------------------------------------------*
 *	send RELEASE COMPLETE message
 *---------------------------------------------------------------------------*/
void
i4b_l3_tx_release_complete(call_desc_t *cd, int send_cause_flag)
{
	struct mbuf *m;
	u_char *ptr;
	int len = I_FRAME_HDRLEN + MSG_RELEASE_COMPLETE_LEN;
	
	if(send_cause_flag == 0)
	{
		len -= 4;
		NDBGL3(L3_PRIM, "unit %d, cr = 0x%02x",
			ctrl_desc[cd->controller].unit, cd->cr);
	}
	else
	{
		NDBGL3(L3_PRIM, "unit=%d, cr=0x%02x, cause=0x%x",
			ctrl_desc[cd->controller].unit, cd->cr, cd->cause_out);
	}
		
	if((m = i4b_Dgetmbuf(len)) == NULL)
		panic("i4b_l3_tx_release_complete: can't allocate mbuf\n");

	ptr = m->m_data + I_FRAME_HDRLEN;
	
	*ptr++ = PD_Q931;		/* protocol discriminator */
	*ptr++ = 0x01;			/* call reference length */
	*ptr++ = setup_cr(cd, cd->cr);	/* call reference value */
	*ptr++ = RELEASE_COMPLETE;	/* message type = release complete */

	if(send_cause_flag)
	{		
		*ptr++ = IEI_CAUSE;		/* cause ie */
		*ptr++ = CAUSE_LEN;
		*ptr++ = CAUSE_STD_LOC_OUT;
		*ptr++ = make_q931_cause(cd->cause_out);
	}

	DL_Data_Req(ctrl_desc[cd->controller].unit, m);
}

/*---------------------------------------------------------------------------*
 *	send DISCONNECT message
 *---------------------------------------------------------------------------*/
void
i4b_l3_tx_disconnect(call_desc_t *cd)
{
	struct mbuf *m;
	u_char *ptr;

	NDBGL3(L3_PRIM, "unit %d, cr = 0x%02x", ctrl_desc[cd->controller].unit, cd->cr);
	
	if((m = i4b_Dgetmbuf(I_FRAME_HDRLEN + MSG_DISCONNECT_LEN)) == NULL)
		panic("i4b_l3_tx_disconnect: can't allocate mbuf\n");

	ptr = m->m_data + I_FRAME_HDRLEN;
	
	*ptr++ = PD_Q931;		/* protocol discriminator */
	*ptr++ = 0x01;			/* call ref length */
	*ptr++ = setup_cr(cd, cd->cr);	/* call reference value */
	*ptr++ = DISCONNECT;		/* message type = disconnect */

	*ptr++ = IEI_CAUSE;		/* cause ie */
	*ptr++ = CAUSE_LEN;
	*ptr++ = CAUSE_STD_LOC_OUT;
	*ptr++ = make_q931_cause(cd->cause_out);

	DL_Data_Req(ctrl_desc[cd->controller].unit, m);
}

/*---------------------------------------------------------------------------*
 *	send SETUP message
 *---------------------------------------------------------------------------*/
void
i4b_l3_tx_setup(call_desc_t *cd)
{
	struct mbuf *m;
	u_char *ptr;
	int len;
	int slen = strlen(cd->src_telno);
	int sslen = strlen(cd->src_subaddr);
	int dlen = strlen(cd->dst_telno);
	int dslen = strlen(cd->dst_subaddr);
	int klen = strlen(cd->keypad);	

	/*
	 * there is one additional octet if cd->bprot == BPROT_NONE
	 * NOTE: the selection of a bearer capability by a B L1
	 *       protocol is highly questionable and a better
	 *       mechanism should be used in future. (-hm)
	 */

	NDBGL3(L3_PRIM, "unit %d, cr = 0x%02x", ctrl_desc[cd->controller].unit, cd->cr);
	
	len = 	I_FRAME_HDRLEN		+
		MSG_SETUP_LEN		+
		(slen ? (3+slen) : 0)	+
		(sslen ? (3+sslen) : 0)	+
		(dlen ? (3+dlen) : 0)	+
		(dslen ? (3+dslen) : 0)	+
		(klen ? (2+klen) : 0)	+
		(cd->bprot == BPROT_NONE ? 1 : 0);

	if((m = i4b_Dgetmbuf(len)) == NULL)
	{
		panic("i4b_l3_tx_setup: can't allocate mbuf\n");
	}

	cd->crflag = CRF_ORIG;		/* we are the originating side */
	
	ptr = m->m_data + I_FRAME_HDRLEN;
	
	*ptr++ = PD_Q931;		/* protocol discriminator */
	*ptr++ = 0x01;			/* call ref length */
	*ptr++ = setup_cr(cd, cd->cr);	/* call reference value */
	*ptr++ = SETUP;			/* message type = setup */

	*ptr++ = IEI_SENDCOMPL;		/* sending complete */	
	
	*ptr++ = IEI_BEARERCAP;		/* bearer capability */

	/* XXX
	 * currently i have no idea if this should be switched by
	 * the choosen B channel protocol or if there should be a
	 * separate configuration item for the bearer capability.
	 * For now, it is switched by the choosen b protocol (-hm)
	 */
	 
	switch(cd->bprot)
	{
		case BPROT_NONE:	/* telephony */
			*ptr++ = IEI_BEARERCAP_LEN+1;
			*ptr++ = IT_CAP_SPEECH;
			*ptr++ = IT_RATE_64K;
			*ptr++ = IT_UL1_G711A;
			break;

		case BPROT_RHDLC:	/* raw HDLC */
			if (cd->bcap == BCAP_DOV) /* Data over Voice */
			{
				*ptr++ = IEI_BEARERCAP_LEN+1;
				*ptr++ = IT_CAP_SPEECH;
				*ptr++ = IT_RATE_64K;
				*ptr++ = IT_UL1_G711A;
			}
			else
			{
				*ptr++ = IEI_BEARERCAP_LEN;
				*ptr++ = IT_CAP_UNR_DIG_INFO;
				*ptr++ = IT_RATE_64K;
			}
			break;

		default:
			*ptr++ = IEI_BEARERCAP_LEN;
			*ptr++ = IT_CAP_UNR_DIG_INFO;
			*ptr++ = IT_RATE_64K;
			break;
	}

	*ptr++ = IEI_CHANNELID;		/* channel id */
	*ptr++ = IEI_CHANNELID_LEN;	/* channel id length */

	switch(cd->channelid)
	{
		case CHAN_B1:
			*ptr++ = CHANNELID_B1;
			break;
		case CHAN_B2:
			*ptr++ = CHANNELID_B2;
			break;
		default:
			*ptr++ = CHANNELID_ANY;
			break;
	}

	if(klen)
	{
		*ptr++ = IEI_KEYPAD;		/* keypad facility */
		*ptr++ = klen;			/* keypad facility length */
		strncpy(ptr, cd->keypad, klen);
		ptr += klen;
	}
	
	if(slen)
	{
		*ptr++ = IEI_CALLINGPN;		/* calling party no */
		*ptr++ = IEI_CALLINGPN_LEN+slen;/* calling party no length */
		*ptr++ = NUMBER_TYPEPLAN;	/* type of number, number plan id */
		strncpy(ptr, cd->src_telno, slen);
		ptr += slen;
	}

	if(sslen)
	{
		*ptr++ = IEI_CALLINGPS;		/* calling subaddr */
		*ptr++ = IEI_CALLINGPS_LEN+sslen; /* calling subaddr len */
		*ptr++ = SUBADDR_TYPE_NSAP;	/* type = NSAP */
		strncpy(ptr, cd->src_subaddr, sslen);
		ptr += sslen;
	}

	if(dlen)
	{
		*ptr++ = IEI_CALLEDPN;		/* called party no */
		*ptr++ = IEI_CALLEDPN_LEN+dlen;	/* called party no length */
		*ptr++ = NUMBER_TYPEPLAN;	/* type of number, number plan id */
		strncpy(ptr, cd->dst_telno, dlen);
		ptr += dlen;
	}

	if(dslen)
	{	
		*ptr++ = IEI_CALLEDPS;		/* calling party subaddr */
		*ptr++ = IEI_CALLEDPS_LEN+dslen;/* calling party subaddr len */
		*ptr++ = SUBADDR_TYPE_NSAP;	/* type = NSAP */
		strncpy(ptr, cd->dst_subaddr, dslen);
		ptr += dslen;
	}
	
	DL_Data_Req(ctrl_desc[cd->controller].unit, m);
}

/*---------------------------------------------------------------------------*
 *	send CONNECT ACKNOWLEDGE message
 *---------------------------------------------------------------------------*/
void
i4b_l3_tx_connect_ack(call_desc_t *cd)
{
	struct mbuf *m;
	u_char *ptr;

	NDBGL3(L3_PRIM, "unit %d, cr = 0x%02x", ctrl_desc[cd->controller].unit, cd->cr);
	
	if((m = i4b_Dgetmbuf(I_FRAME_HDRLEN + MSG_CONNECT_ACK_LEN)) == NULL)
		panic("i4b_l3_tx_connect_ack: can't allocate mbuf\n");

	ptr = m->m_data + I_FRAME_HDRLEN;
	
	*ptr++ = PD_Q931;		/* protocol discriminator */
	*ptr++ = 0x01;			/* call reference length */
	*ptr++ = setup_cr(cd, cd->cr);	/* call reference value */
	*ptr++ = CONNECT_ACKNOWLEDGE;	/* message type = connect ack */

	DL_Data_Req(ctrl_desc[cd->controller].unit, m);
}

/*---------------------------------------------------------------------------*
 *	send STATUS message
 *---------------------------------------------------------------------------*/
void
i4b_l3_tx_status(call_desc_t *cd, u_char q850cause)
{
	struct mbuf *m;
	u_char *ptr;

	NDBGL3(L3_PRIM, "unit %d, cr = 0x%02x", ctrl_desc[cd->controller].unit, cd->cr);
	
	if((m = i4b_Dgetmbuf(I_FRAME_HDRLEN + MSG_STATUS_LEN)) == NULL)
		panic("i4b_l3_tx_status: can't allocate mbuf\n");

	ptr = m->m_data + I_FRAME_HDRLEN;
	
	*ptr++ = PD_Q931;		/* protocol discriminator */
	*ptr++ = 0x01;			/* call reference length */
	*ptr++ = setup_cr(cd, cd->cr);	/* call reference value */
	*ptr++ = STATUS;	/* message type = connect ack */

	*ptr++ = IEI_CAUSE;		/* cause ie */
	*ptr++ = CAUSE_LEN;
	*ptr++ = CAUSE_STD_LOC_OUT;
	*ptr++ = q850cause | EXT_LAST;

	*ptr++ = IEI_CALLSTATE;		/* call state ie */
	*ptr++ = CALLSTATE_LEN;
	*ptr++ = i4b_status_tab[cd->Q931state];
		
	DL_Data_Req(ctrl_desc[cd->controller].unit, m);
}

/*---------------------------------------------------------------------------*
 *	send RELEASE message
 *---------------------------------------------------------------------------*/
void
i4b_l3_tx_release(call_desc_t *cd, int send_cause_flag)
{
	struct mbuf *m;
	u_char *ptr;
	int len = I_FRAME_HDRLEN + MSG_RELEASE_LEN;

	NDBGL3(L3_PRIM, "unit %d, cr = 0x%02x", ctrl_desc[cd->controller].unit, cd->cr);
	
	if(send_cause_flag == 0)
		len -= 4;

	if((m = i4b_Dgetmbuf(len)) == NULL)
		panic("i4b_l3_tx_release: can't allocate mbuf\n");

	ptr = m->m_data + I_FRAME_HDRLEN;
	
	*ptr++ = PD_Q931;		/* protocol discriminator */
	*ptr++ = 0x01;			/* call reference length */
	*ptr++ = setup_cr(cd, cd->cr);	/* call reference value */
	*ptr++ = RELEASE;		/* message type = release complete */

	if(send_cause_flag)
	{
		*ptr++ = IEI_CAUSE;		/* cause ie */
		*ptr++ = CAUSE_LEN;
		*ptr++ = CAUSE_STD_LOC_OUT;
		*ptr++ = make_q931_cause(cd->cause_out);
	}

	DL_Data_Req(ctrl_desc[cd->controller].unit, m);
}

/*---------------------------------------------------------------------------*
 *	send ALERTING message
 *---------------------------------------------------------------------------*/
void
i4b_l3_tx_alert(call_desc_t *cd)
{
	struct mbuf *m;
	u_char *ptr;

	if((m = i4b_Dgetmbuf(I_FRAME_HDRLEN + MSG_ALERT_LEN)) == NULL)
		panic("i4b_l3_tx_alert: can't allocate mbuf\n");

	NDBGL3(L3_PRIM, "unit %d, cr = 0x%02x", ctrl_desc[cd->controller].unit, cd->cr);
	
	ptr = m->m_data + I_FRAME_HDRLEN;
	
	*ptr++ = PD_Q931;		/* protocol discriminator */
	*ptr++ = 0x01;			/* call reference length */
	*ptr++ = setup_cr(cd, cd->cr);	/* call reference value */
	*ptr++ = ALERT;			/* message type = alert */

	DL_Data_Req(ctrl_desc[cd->controller].unit, m);
}