path: root/sys/netiso/if_cons.c

/*	$OpenBSD: if_cons.c,v 1.4 2002/03/14 01:27:12 millert Exp $	*/
/*	$NetBSD: if_cons.c,v 1.7 1996/02/13 22:09:44 christos Exp $	*/

/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *	@(#)if_cons.c	8.1 (Berkeley) 6/10/93
 */

/***********************************************************
		Copyright IBM Corporation 1987

                      All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the name of IBM not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.

IBM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
IBM BE LIABLE FOR 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.

******************************************************************/

/*
 * ARGO Project, Computer Sciences Dept., University of Wisconsin - Madison
 */
/*
 * cons.c - Connection Oriented Network Service:
 * including support for a) user transport-level service,
 *	b) COSNS below CLNP, and c) CONS below TP.
 */

#ifdef TPCONS
#ifdef _KERNEL
#ifdef ARGO_DEBUG
#define Static
unsigned        LAST_CALL_PCB;
#else				/* ARGO_DEBUG */
#define Static static
#endif				/* ARGO_DEBUG */

#ifndef SOCK_STREAM
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/errno.h>
#include <sys/ioctl.h>

#include <net/if.h>
#include <net/netisr.h>
#include <net/route.h>

#include <netiso/iso_errno.h>
#include <netiso/argo_debug.h>
#include <netiso/tp_trace.h>
#include <netiso/iso.h>
#include <netiso/cons.h>
#include <netiso/iso_pcb.h>
#include <netiso/iso_var.h>
#include <netiso/tp_var.h>
#include <netiso/clnp.h>

#include <netccitt/x25.h>
#include <netccitt/pk.h>
#include <netccitt/pk_var.h>
#include <netccitt/pk_extern.h>
#endif

#ifdef ARGO_DEBUG
#define MT_XCONN	0x50
#define MT_XCLOSE	0x51
#define MT_XCONFIRM	0x52
#define MT_XDATA	0x53
#define MT_XHEADER	0x54
#else
#define MT_XCONN	MT_DATA
#define MT_XCLOSE	MT_DATA
#define MT_XCONFIRM	MT_DATA
#define MT_XDATA	MT_DATA
#define MT_XHEADER	MT_HEADER
#endif	/* ARGO_DEBUG */

#define DONTCLEAR	 -1

/*********************************************************************
 * cons.c - CONS interface to the x.25 layer
 *
 * TODO: figure out what resources we might run out of besides mbufs.
 *  If we run out of any of them (including mbufs) close and recycle
 *  lru x% of the connections, for some parameter x.
 *
 * There are 2 interfaces from above:
 * 1) from TP0:
 *    cons CO network service
 *    TP associates a transport connection with a network connection.
 * 	  cons_output( isop, m, len, isdgm==0 )
 *        co_flags == 0
 * 2) from TP4:
 *	  It's a datagram service, like clnp is. - even though it calls
 *			cons_output( isop, m, len, isdgm==1 )
 *	  it eventually goes through
 *			cosns_output(ifp, m, dst).
 *    TP4 permits multiplexing (reuse, possibly simultaneously) of the
 *	  network connections.
 *    This means that many sockets (many tpcbs) may be associated with
 *    this pklcd, hence cannot have a back ptr from pklcd to a tpcb.
 *        co_flags & CONSF_DGM
 *    co_socket is null since there may be many sockets that use this pklcd.
 * NOTE:
 *	streams would really be nice. sigh.
 * NOTE:
 *	PVCs could be handled by config-ing a cons with an address and with the
 *	IFF_POINTTOPOINT flag on.  This code would then have to skip the
 *	connection setup stuff for pt-to-pt links.
 *
 *********************************************************************/


#define CONS_IFQMAXLEN 5

Static int make_partial_x25_packet(struct isopcb *, struct pklcd *);
Static int NSAPtoDTE(struct sockaddr_iso *, struct sockaddr_x25 *);
Static int FACILtoNSAP(struct sockaddr_iso *, u_char *);
Static void init_siso(struct sockaddr_iso *);
Static int DTEtoNSAP(struct sockaddr_iso *, struct sockaddr_x25 *);
Static int parse_facil(struct pklcd *, struct isopcb *, caddr_t, u_char);

/* protosw pointers for getting to higher layer */
Static struct protosw *CLNP_proto;
Static struct protosw *TP_proto;
Static struct protosw *X25_proto;

extern struct isopcb tp_isopcb;	/* chain of all TP pcbs */


#define HIGH_NIBBLE 1
#define LOW_NIBBLE 0

/*
 * NAME:	nibble_copy()
 * FUNCTION and ARGUMENTS:
 * 	copies (len) nibbles from (src_octet), high or low nibble
 *  to (dst_octet), high or low nibble,
 * src_nibble & dst_nibble should be:
 * 	HIGH_NIBBLE (1) if leftmost 4 bits/ most significant nibble
 * 	LOW_NIBBLE (0) if rightmost 4 bits/ least significant nibble
 * RETURNS: VOID
 */
void
nibble_copy(src_octet, src_nibble, dst_octet, dst_nibble, len)
	register char  *src_octet;
	register char  *dst_octet;
	register unsigned src_nibble;
	register unsigned dst_nibble;
	int             len;
{

	register        i;
	register unsigned dshift, sshift;

#ifdef ARGO_DEBUG
	if (argo_debug[D_CADDR]) {
		printf("nibble_copy ( 0x%x, 0x%x, 0x%x, 0x%x 0x%x)\n",
		       src_octet, src_nibble, dst_octet, dst_nibble, len);
	}
#endif
#define SHIFT 0x4

	dshift = dst_nibble << 2;
	sshift = src_nibble << 2;

	for (i = 0; i < len; i++) {
		/* clear dst_nibble  */
		*dst_octet &= ~(0xf << dshift);

		/* set dst nibble */
		*dst_octet |= (0xf & (*src_octet >> sshift)) << dshift;

		dshift ^= SHIFT;
		sshift ^= SHIFT;
		src_nibble = 1 - src_nibble;
		dst_nibble = 1 - dst_nibble;
		src_octet += src_nibble;
		dst_octet += dst_nibble;
	}
#ifdef ARGO_DEBUG
	if (argo_debug[D_CADDR]) {
		printf("nibble_copy DONE\n");
	}
#endif
}

/*
 * NAME:	nibble_match()
 * FUNCTION and ARGUMENTS:
 * 	compares src_octet/src_nibble and dst_octet/dst_nibble  for len nibbles.
 * RETURNS: 0 if they differ, 1 if they are the same.
 */
int
nibble_match(src_octet, src_nibble, dst_octet, dst_nibble, len)
	register char  *src_octet;
	register char  *dst_octet;
	register unsigned src_nibble;
	register unsigned dst_nibble;
	int             len;
{

	register        i;
	register unsigned dshift, sshift;
	u_char          nibble_a, nibble_b;

#ifdef ARGO_DEBUG
	if (argo_debug[D_CADDR]) {
		printf("nibble_match ( 0x%x, 0x%x, 0x%x, 0x%x 0x%x)\n",
		       src_octet, src_nibble, dst_octet, dst_nibble, len);
	}
#endif
#define SHIFT 0x4

	dshift = dst_nibble << 2;
	sshift = src_nibble << 2;

	for (i = 0; i < len; i++) {
		nibble_b = ((*dst_octet) >> dshift) & 0xf;
		nibble_a = (0xf & (*src_octet >> sshift));
		if (nibble_b != nibble_a)
			return 0;

		dshift ^= SHIFT;
		sshift ^= SHIFT;
		src_nibble = 1 - src_nibble;
		dst_nibble = 1 - dst_nibble;
		src_octet += src_nibble;
		dst_octet += dst_nibble;
	}
#ifdef ARGO_DEBUG
	if (argo_debug[D_CADDR]) {
		printf("nibble_match DONE\n");
	}
#endif
	return 1;
}

/*
 **************************** NET PROTOCOL cons ***************************
 */
/*
 * NAME:	cons_init()
 * CALLED FROM:
 *	autoconf
 * FUNCTION:
 *	initialize the protocol
 */
void
cons_init()
{
	CLNP_proto = pffindproto(AF_ISO, ISOPROTO_CLNP, SOCK_DGRAM);
	X25_proto = pffindproto(AF_ISO, ISOPROTO_X25, SOCK_STREAM);
	TP_proto = pffindproto(AF_ISO, ISOPROTO_TP0, SOCK_SEQPACKET);
#ifdef ARGO_DEBUG
	if (argo_debug[D_CCONS]) {
		printf("cons_init end : cnlp_proto 0x%x cons proto 0x%x tp proto 0x%x\n",
		       CLNP_proto, X25_proto, TP_proto);
	}
#endif
#ifdef notdef
	pk_protolisten(0x81, 0, clnp_incoming);
	pk_protolisten(0x82, 0, esis_incoming);
	pk_protolisten(0x84, 0, tp8878_A_incoming);
	pk_protolisten(0, 0, tp_incoming);
#endif
}

int
tp_incoming(m, v)
	register struct mbuf *m;
	void *v;
{
	struct pklcd   *lcp = v;
	register struct isopcb *isop;

	if (iso_pcballoc(NULL, &tp_isopcb)) {
		pk_close(lcp);
		return 0;
	}
	isop = tp_isopcb.isop_next;
	lcp->lcd_upper = cons_tpinput;
	lcp->lcd_upnext = (caddr_t) isop;
	lcp->lcd_send(lcp);	/* Confirms call */
	isop->isop_chan = (caddr_t) lcp;
	isop->isop_laddr = &isop->isop_sladdr;
	isop->isop_faddr = &isop->isop_sfaddr;
	DTEtoNSAP(isop->isop_laddr, &lcp->lcd_laddr);
	DTEtoNSAP(isop->isop_faddr, &lcp->lcd_faddr);
	parse_facil(lcp, isop, &(mtod(m, struct x25_packet *)->packet_data),
		    m->m_pkthdr.len - PKHEADERLN);
	return 0;
}

int
cons_tpinput(m0, v)
	struct mbuf    *m0;
	void *v;
{
	struct pklcd   *lcp = v;
	register struct isopcb *isop = (struct isopcb *) lcp->lcd_upnext;
	int             cmd, ptype = PK_CLEAR;

	if (isop == 0)
		return 0;
	if (m0 == 0)
		goto dead;
	switch (m0->m_type) {
	case MT_DATA:
	case MT_OOBDATA:
		tpcons_input(m0, isop->isop_faddr, isop->isop_laddr,
			     (caddr_t) lcp);
		return 0;

	case MT_CONTROL:
		switch (ptype = pk_decode(mtod(m0, struct x25_packet *))) {

		case PK_RR:
			cmd = PRC_CONS_SEND_DONE;
			break;

		case PK_CALL_ACCEPTED:
			if (lcp->lcd_sb.sb_mb)
				lcp->lcd_send(lcp);	/* XXX - fix this */
			/* FALLTHROUGH */
		default:
			return 0;

	dead:
		case PK_CLEAR:
		case PK_CLEAR_CONF:
			lcp->lcd_upper = 0;
			lcp->lcd_upnext = 0;
			isop->isop_chan = 0;
		case PK_RESET:
			cmd = PRC_ROUTEDEAD;
		}
		tpcons_ctlinput(cmd, (struct sockaddr *) isop->isop_faddr,
				isop);
		if (cmd == PRC_ROUTEDEAD && isop->isop_refcnt == 0)
			iso_pcbdetach(isop);
	}
	return 0;
}

/*
 * NAME:	cons_connect()
 * CALLED FROM:
 *	tpcons_pcbconnect() when opening a new connection.
 * FUNCTION anD ARGUMENTS:
 *  Figures out which device to use, finding a route if one doesn't
 *  already exist.
 * RETURN VALUE:
 *  returns E*
 */
int
cons_connect(isop)
	register struct isopcb *isop;
{
	register struct pklcd *lcp = (struct pklcd *) isop->isop_chan;
	int             error;

#ifdef ARGO_DEBUG
	if (argo_debug[D_CCONN]) {
		printf("cons_connect(0x%x): ", isop);
		dump_isoaddr(isop->isop_faddr);
		printf("myaddr: ");
		dump_isoaddr(isop->isop_laddr);
		printf("\n");
	}
#endif
	NSAPtoDTE(isop->isop_faddr, &lcp->lcd_faddr);
	lcp->lcd_upper = cons_tpinput;
	lcp->lcd_upnext = (caddr_t) isop;
#ifdef ARGO_DEBUG
	if (argo_debug[D_CCONN]) {
		printf(
		     "calling make_partial_x25_packet( 0x%x, 0x%x, 0x%x)\n",
		       &lcp->lcd_faddr, &lcp->lcd_laddr,
		       isop->isop_socket->so_proto->pr_protocol);
	}
#endif
	if ((error = make_partial_x25_packet(isop, lcp)) == 0)
		error = pk_connect(lcp, &lcp->lcd_faddr);
	return error;
}

/*
 **************************** DEVICE cons ***************************
 */


/*
 * NAME:	cons_ctlinput() CALLED FROM: lower layer when ECN_CLEAR
 * occurs : this routine is here for consistency - cons subnet service calls
 * its higher layer through the protosw entry. FUNCTION & ARGUMENTS: cmd is a
 * PRC_* command, list found in ../sys/protosw.h copcb is the obvious. This
 * serves the higher-layer cons service. NOTE: this takes 3rd arg. because
 * cons uses it to inform itself of things (timeouts, etc) but has a pcb
 * instead of an address.
 */
void *
cons_ctlinput(cmd, sa, v)
	int             cmd;
	struct sockaddr *sa;
	void *v;
{
	return NULL;
}


int
find_error_reason(xp)
	register struct x25_packet *xp;
{
	int             error, cause = 0;

	if (xp) {
		cause = 4[(char *) xp];
		switch (cause) {
		case 0x00:
		case 0x80:
			/* DTE originated; look at the diagnostic */
			error = (CONL_ERROR_MASK | cause);
			goto done;

		case 0x01:	/* number busy */
		case 0x81:
		case 0x09:	/* Out of order */
		case 0x89:
		case 0x11:	/* Remot Procedure Error */
		case 0x91:
		case 0x19:	/* reverse charging accept not subscribed */
		case 0x99:
		case 0x21:	/* Incampat destination */
		case 0xa1:
		case 0x29:	/* fast select accept not subscribed */
		case 0xa9:
		case 0x39:	/* ship absent */
		case 0xb9:
		case 0x03:	/* invalid facil request */
		case 0x83:
		case 0x0b:	/* access barred */
		case 0x8b:
		case 0x13:	/* local procedure error */
		case 0x93:
		case 0x05:	/* network congestion */
		case 0x85:
		case 0x8d:	/* not obtainable */
		case 0x0d:
		case 0x95:	/* RPOA out of order */
		case 0x15:
			/*
			 * take out bit 8 so we don't have to have so many
			 * perror entries
			 */
			error = (CONL_ERROR_MASK | 0x100 | (cause & ~0x80));
			goto done;

		case 0xc1:	/* gateway-detected proc error */
		case 0xc3:	/* gateway congestion */

			error = (CONL_ERROR_MASK | 0x100 | cause);
			goto done;
		}
	}
	/* otherwise, a *hopefully* valid perror exists in the e_reason field */
	error = xp->packet_data;
	if (error == 0) {
		printf("Incoming PKT TYPE 0x%x with reason 0x%x\n",
		       pk_decode(xp),
		       cause);
		error = E_CO_HLI_DISCA;
	}
done:
	return error;
}



#endif				/* _KERNEL */

/*
 * NAME:	make_partial_x25_packet()
 *
 * FUNCTION and ARGUMENTS:
 *	Makes part of an X.25 call packet, for use by x25.
 *  (src) and (dst) are the NSAP-addresses of source and destination.
 *	(buf) is a ptr to a buffer into which to write this partial header.
 *
 *	 0			Facility length (in octets)
 *	 1			Facility field, which is a set of:
 *	  m			facil code
 *	  m+1		facil param len (for >2-byte facilities) in octets
 *	  m+2..p	facil param field
 *  q			user data (protocol identification octet)
 *
 *
 * RETURNS:
 *  0 if OK
 *  E* if failed.
 *
 * SIDE EFFECTS:
 * Stores facilites mbuf in X.25 control block, where the connect
 * routine knows where to look for it.
 */

#ifdef X25_1984
int             cons_use_facils = 1;
#else /* X25_1984  */
int             cons_use_facils = 0;
#endif /* X25_1984  */

int  cons_use_udata = 1;	/* KLUDGE FOR DEBUGGING */

Static int
make_partial_x25_packet(isop, lcp)
	struct isopcb  *isop;
	struct pklcd   *lcp;
{
	u_int           proto = 0;
	int             flag = 0;
	caddr_t         buf;
	register caddr_t ptr;
	register int    len = 0;
	int             buflen = 0;
	caddr_t         facil_len;
	struct mbuf    *m = NULL;


#ifdef ARGO_DEBUG
	if (argo_debug[D_CCONN]) {
		printf("make_partial_x25_packet(0x%x, 0x%x, 0x%x, 0x%x, 0x%x)\n",
		       isop->isop_laddr, isop->isop_faddr, proto, m, flag);
	}
#endif
	if (cons_use_udata) {
		if (isop->isop_x25crud_len > 0) {
			/*
			 *	The user specified something. Stick it in
			 */
			bcopy(isop->isop_x25crud, lcp->lcd_faddr.x25_udata,
			      isop->isop_x25crud_len);
			lcp->lcd_faddr.x25_udlen = isop->isop_x25crud_len;
		}
	}
	if (cons_use_facils == 0) {
		lcp->lcd_facilities = 0;
		return 0;
	}
	MGETHDR(m, M_WAITOK, MT_DATA);
	buf = mtod(m, caddr_t);
	ptr = buf;

	/* ptr now points to facil length (len of whole facil field in OCTETS */
	facil_len = ptr++;
	m->m_len = 0;
	pk_build_facilities(m, &lcp->lcd_faddr, 0);

#ifdef ARGO_DEBUG
	if (argo_debug[D_CADDR]) {
		printf("make_partial  calling: ptr 0x%x, len 0x%x\n", ptr,
		       isop->isop_laddr->siso_addr.isoa_len);
	}
#endif
	if (cons_use_facils) {
		*ptr++ = 0;	/* Marker to separate X.25 facitilies from
				 * CCITT ones */
		*ptr++ = 0x0f;
		*ptr = 0xcb;	/* calling facility code */
		ptr++;
		ptr++;		/* leave room for facil param len (in OCTETS
				 * + 1) */
		ptr++;		/* leave room for the facil param len (in
				 * nibbles), high two bits of which indicate
				 * full/partial NSAP */
		len = isop->isop_laddr->siso_addr.isoa_len;
		bcopy(isop->isop_laddr->siso_data, ptr, len);
		*(ptr - 2) = len + 1;	/* facil param len in octets */
		*(ptr - 1) = len << 1;	/* facil param len in nibbles */
		ptr += len;

#ifdef ARGO_DEBUG
		if (argo_debug[D_CADDR]) {
			printf("make_partial  called: ptr 0x%x, len 0x%x\n", ptr,
			       isop->isop_faddr->siso_addr.isoa_len);
		}
#endif
		*ptr = 0xc9;	/* called facility code */
		ptr++;
		ptr++;		/* leave room for facil param len (in OCTETS
				 * + 1) */
		ptr++;		/* leave room for the facil param len (in
				 * nibbles), high two bits of which indicate
				 * full/partial NSAP */
		len = isop->isop_faddr->siso_nlen;
		bcopy(isop->isop_faddr->siso_data, ptr, len);
		*(ptr - 2) = len + 1;	/* facil param len = addr len + 1 for
					 * each of these two length fields,
					 * in octets */
		*(ptr - 1) = len << 1;	/* facil param len in nibbles */
		ptr += len;

	}
	*facil_len = ptr - facil_len - 1;
	if (*facil_len > MAX_FACILITIES)
		return E_CO_PNA_LONG;

	buflen = (int) (ptr - buf);

#ifdef ARGO_DEBUG
	if (argo_debug[D_CDUMP_REQ]) {
		register int    i;

		printf("ECN_CONNECT DATA buf 0x%x len %d (0x%x)\n",
		       buf, buflen, buflen);
		for (i = 0; i < buflen;) {
			printf("+%d: %x %x %x %x    %x %x %x %x\n",
			       i,
			       *(buf + i), *(buf + i + 1), *(buf + i + 2), *(buf + i + 3),
			       *(buf + i + 4), *(buf + i + 5), *(buf + i + 6), *(buf + i + 7));
			i += 8;
		}
	}
#endif
#ifdef ARGO_DEBUG
	if (argo_debug[D_CADDR]) {
		printf("make_partial returns buf 0x%x size 0x%x bytes\n",
		       mtod(m, caddr_t), buflen);
	}
#endif

	if (buflen > MHLEN)
		return E_CO_PNA_LONG;

	m->m_pkthdr.len = m->m_len = buflen;
	lcp->lcd_facilities = m;
	return 0;
}

/*
 * NAME:	NSAPtoDTE()
 * CALLED FROM:
 *  make_partial_x25_packet()
 * FUNCTION and ARGUMENTS:
 *  get a DTE address from an NSAP-address (struct sockaddr_iso)
 *  (dst_octet) is the octet into which to begin stashing the DTE addr
 *  (dst_nibble) takes 0 or 1.  1 means begin filling in the DTE addr
 * 		in the high-order nibble of dst_octet.  0 means low-order nibble.
 *  (addr) is the NSAP-address
 *  (flag) is true if the transport suffix is to become the
 *		last two digits of the DTE address
 *  A DTE address is a series of ASCII digits
 *
 *	A DTE address may have leading zeros. The are significant.
 *		1 digit per nibble, may be an odd number of nibbles.
 *
 *  An NSAP-address has the DTE address in the IDI. Leading zeros are
 *		significant. Trailing hex f indicates the end of the DTE address.
 *  	The IDI is a series of BCD digits, one per nibble.
 *
 * RETURNS
 *  # significant digits in the DTE address, -1 if error.
 */

Static int
NSAPtoDTE(siso, sx25)
	register struct sockaddr_iso *siso;
	register struct sockaddr_x25 *sx25;
{
	int             dtelen = -1;

#ifdef ARGO_DEBUG
	if (argo_debug[D_CADDR]) {
		printf("NSAPtoDTE: nsap: %s\n",
			clnp_iso_addrp(&siso->siso_addr));
	}
#endif

	if (siso->siso_data[0] == AFI_37) {
		register char  *out = sx25->x25_addr;
		register char  *in = siso->siso_data + 1;
		register int    nibble;
		char           *lim = siso->siso_data + siso->siso_nlen;
		char           *olim = out + 15;
		int             lowNibble = 0;

		while (in < lim) {
			nibble = ((lowNibble ? *in++ : (*in >> 4)) & 0xf) | 0x30;
			lowNibble ^= 1;
			if (nibble != 0x3f && out < olim)
				*out++ = nibble;
		}
		dtelen = out - sx25->x25_addr;
		*out++ = 0;
	} else {
		/*
		 * error = iso_8208snparesolve(addr, x121string,
		 * &x121strlen);
		 */
		register struct rtentry *rt;
		extern struct sockaddr_iso blank_siso;
		struct sockaddr_iso nsiso;

		nsiso = blank_siso;
		bcopy(nsiso.siso_data, siso->siso_data,
		      nsiso.siso_nlen = siso->siso_nlen);
		if ((rt = rtalloc1((struct sockaddr *) &nsiso, 1)) != NULL) {
			register struct sockaddr_x25 *sxx =
			(struct sockaddr_x25 *) rt->rt_gateway;
			register char  *in = sxx->x25_addr;

			rt->rt_use--;
			if (sxx && sxx->x25_family == AF_CCITT) {
				bcopy(sx25->x25_addr, sxx->x25_addr, sizeof(sx25->x25_addr));
				while (*in++) {
				}
				dtelen = in - sxx->x25_addr;
			}
		}
	}
	return dtelen;
}

/*
 * NAME:	FACILtoNSAP()
 * CALLED FROM:
 *  parse_facil()
 * FUNCTION and ARGUMENTS:
 * 	Creates and NSAP in the sockaddr_iso (addr) from the
 *  x.25 facility found at buf - 1.
 * RETURNS:
 *  0 if ok, -1 if error.
 */

Static int
FACILtoNSAP(addr, buf)
	register u_char *buf;
	register struct sockaddr_iso *addr;
{
	int             len_in_nibbles = *++buf & 0x3f;
	u_char          buf_len = (len_in_nibbles + 1) >> 1;;	/* in bytes */

#ifdef ARGO_DEBUG
	if (argo_debug[D_CADDR]) {
		printf("FACILtoNSAP( 0x%x, 0x%x, 0x%x )\n",
		       buf, buf_len, addr);
	}
#endif

	len_in_nibbles = *buf & 0x3f;
	/*
	 * despite the fact that X.25 makes us put a length in nibbles here,
	 * the NSAP-addrs are always in full octets
	 */
	switch (*buf++ & 0xc0) {
	case 0:
		/* Entire OSI NSAP address */
		bcopy((caddr_t) buf, addr->siso_data, addr->siso_nlen = buf_len);
		break;

	case 40:
		/* Partial OSI NSAP address, assume trailing */
		if (buf_len + addr->siso_nlen > sizeof(addr->siso_addr))
			return -1;
		bcopy((caddr_t) buf, TSEL(addr), buf_len);
		addr->siso_nlen += buf_len;
		break;

	default:
		/*
		 * Rather than blow away the connection, just ignore and use
		 * NSAP from DTE
		 		 */ ;
	}
	return 0;
}

Static void
init_siso(siso)
	register struct sockaddr_iso *siso;
{
	siso->siso_len = sizeof(*siso);
	siso->siso_family = AF_ISO;
	siso->siso_data[0] = AFI_37;
	siso->siso_nlen = 8;
}

/*
 * NAME:	DTEtoNSAP()
 * CALLED FROM:
 *  parse_facil()
 * FUNCTION and ARGUMENTS:
 *  Creates a type 37 NSAP in the sockaddr_iso (addr)
 * 	from a DTE address found in a sockaddr_x25.
 *
 * RETURNS:
 *  0 if ok; E* otherwise.
 */

Static int
DTEtoNSAP(addr, sx)
	struct sockaddr_iso *addr;
	struct sockaddr_x25 *sx;
{
	register char  *in, *out;
	register int    first;
	int             pad_tail = 0;
	int             src_len;


	init_siso(addr);
	in = sx->x25_addr;
	src_len = strlen(in);
	addr->siso_nlen = (src_len + 3) / 2;
	out = addr->siso_data;
	*out++ = 0x37;
	if (src_len & 1) {
		pad_tail = 0xf;
		src_len++;
	}
	for (first = 0; src_len > 0; src_len--) {
		first |= 0xf & *in++;
		if (src_len & 1) {
			*out++ = first;
			first = 0;
		} else
			first <<= 4;
	}
	if (pad_tail)
		out[-1] |= 0xf;
	return 0;		/* ok */
}

/*
 * FUNCTION and ARGUMENTS:
 *	parses (buf_len) bytes beginning at (buf) and finds
 *  a called nsap, a calling nsap, and protocol identifier.
 * RETURNS:
 *  0 if ok, E* otherwise.
 */

Static int
parse_facil(lcp, isop, buf, buf_len)
	caddr_t         buf;
	u_char          buf_len;/* in bytes */
	struct isopcb  *isop;
	struct pklcd   *lcp;
{
	register int    i;
	register u_char *ptr = (u_char *) buf;
	u_char         *facil_lim;
	int             facil_param_len = 0, facil_len;

#ifdef ARGO_DEBUG
	if (argo_debug[D_CADDR]) {
		printf("parse_facil(0x%x, 0x%x, 0x%x, 0x%x)\n",
		       lcp, isop, buf, buf_len);
		dump_buf(buf, buf_len);
	}
#endif

	/*
	 * find the beginnings of the facility fields in buf by skipping over
	 * the called & calling DTE addresses i <- # nibbles in called + #
	 * nibbles in calling i += 1 so that an odd nibble gets rounded up to
	 * even  before dividing by 2, then divide by two to get # octets
	 */
	i = (int) (*ptr >> 4) + (int) (*ptr & 0xf);
	i++;
	ptr += i >> 1;
	ptr++;			/* plus one for the DTE lengths byte */

	/* ptr now is at facil_length field */
	facil_len = *ptr++;
	facil_lim = ptr + facil_len;
#ifdef ARGO_DEBUG
	if (argo_debug[D_CADDR]) {
		printf("parse_facils: facil length is  0x%x\n", (int) facil_len);
	}
#endif

	while (ptr < facil_lim) {
		/* get NSAP addresses from facilities */
		switch (*ptr++) {
		case 0xcb:
			/* calling NSAP */
			facil_param_len = FACILtoNSAP(isop->isop_faddr, ptr);
			break;
		case 0xc9:
			/* called NSAP */
			facil_param_len = FACILtoNSAP(isop->isop_laddr, ptr);
			break;

			/* from here to default are legit cases that I ignore */
			/* variable length */
		case 0xca:	/* end-to-end transit delay negot */
		case 0xc6:	/* network user id */
		case 0xc5:	/* charging info : indicating monetary unit */
		case 0xc2:	/* charging info : indicating segment count */
		case 0xc1:	/* charging info : indicating call duration */
		case 0xc4:	/* RPOA extended format */
		case 0xc3:	/* call redirection notification */
			facil_param_len = 0;
			break;

			/* 1 octet */
		case 0x0a:	/* min. throughput class negot */
		case 0x02:	/* throughput class */
		case 0x03:
		case 0x47:	/* CUG shit */
		case 0x0b:	/* expedited data negot */
		case 0x01:	/* Fast select or reverse charging (example
				 * of intelligent protocol design) */
		case 0x04:	/* charging info : requesting service */
		case 0x08:	/* called line addr modified notification */
		case 0x00:	/* marker to indicate beginning of CCITT
				 * facils */
			facil_param_len = 1;
			break;

			/* any 2 octets */
		case 0x42:	/* pkt size */
		case 0x43:	/* win size */
		case 0x44:	/* RPOA basic format */
		case 0x41:	/* bilateral CUG shit */
		case 0x49:	/* transit delay selection and indication */
			facil_param_len = 2;
			break;

		default:
			printf(
			       "BOGUS FACILITY CODE facil_lim 0x%x facil_len %d, ptr 0x%x *ptr 0x%x\n",
			       facil_lim, facil_len, ptr - 1, ptr[-1]);
			/*
			 * facil that we don't handle return E_CO_HLI_REJI;
			 */
			switch (ptr[-1] & 0xc0) {
			case 0x00:
				facil_param_len = 1;
				break;
			case 0x40:
				facil_param_len = 2;
				break;
			case 0x80:
				facil_param_len = 3;
				break;
			case 0xc0:
				facil_param_len = 0;
				break;
			}
		}
		if (facil_param_len == -1)
			return E_CO_REG_ICDA;
		if (facil_param_len == 0)	/* variable length */
			facil_param_len = (int) *ptr++;	/* 1 + the real facil
							 * param */
		ptr += facil_param_len;
	}
	return 0;
}

#endif				/* TPCONS */