path: root/sys/netccitt/pk_subr.c

/*	$OpenBSD: pk_subr.c,v 1.7 2003/02/18 13:14:43 jmc Exp $	*/
/*	$NetBSD: pk_subr.c,v 1.12 1996/03/30 21:54:33 christos Exp $	*/

/*
 * Copyright (c) University of British Columbia, 1984
 * Copyright (C) Computer Science Department IV,
 * 		 University of Erlangen-Nuremberg, Germany, 1992
 * Copyright (c) 1991, 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by the
 * Laboratory for Computation Vision and the Computer Science Department
 * of the the University of British Columbia and the Computer Science
 * Department (IV) of the University of Erlangen-Nuremberg, Germany.
 *
 * 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.
 *
 *	@(#)pk_subr.c	8.1 (Berkeley) 6/10/93
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/socketvar.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>

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

#include <netccitt/dll.h>
#include <netccitt/x25.h>
#include <netccitt/x25err.h>
#include <netccitt/pk.h>
#include <netccitt/pk_var.h>
#include <netccitt/pk_extern.h>

#include <machine/stdarg.h>

int             pk_sendspace = 1024 * 2 + 8;
int             pk_recvspace = 1024 * 2 + 8;

struct pklcd_q  pklcd_q = {&pklcd_q, &pklcd_q};

struct x25bitslice x25_bitslice[] = {
	/* mask, shift value */
	{0xf0, 0x4},
	{0xf, 0x0},
	{0x80, 0x7},
	{0x40, 0x6},
	{0x30, 0x4},
	{0xe0, 0x5},
	{0x10, 0x4},
	{0xe, 0x1},
	{0x1, 0x0}
};


static struct x25_ifaddr *pk_ifwithaddr(struct sockaddr_x25 *);
static void pk_reset(struct pklcd *, int);

/*
 * Attach X.25 protocol to socket, allocate logical channel descripter and
 * buffer space, and enter LISTEN state if we are to accept IN-COMMING CALL
 * packets.
 * 
 */

struct pklcd *
pk_attach(so)
	struct socket  *so;
{
	register struct pklcd *lcp;
	register int    error = ENOBUFS;

	MALLOC(lcp, struct pklcd *, sizeof(*lcp), M_PCB, M_NOWAIT);
	if (lcp) {
		bzero((caddr_t) lcp, sizeof(*lcp));
		insque(&lcp->lcd_q, &pklcd_q);
		lcp->lcd_state = READY;
		lcp->lcd_send = pk_output;
		if (so) {
			error = soreserve(so, pk_sendspace, pk_recvspace);
			lcp->lcd_so = so;
			if (so->so_options & SO_ACCEPTCONN)
				lcp->lcd_state = LISTEN;
		} else
			sbreserve(&lcp->lcd_sb, pk_sendspace);
	}
	if (so) {
		so->so_pcb = lcp;
		so->so_error = error;
	}
	return (lcp);
}

/*
 * Disconnect X.25 protocol from socket.
 */
void
pk_disconnect(lcp)
	register struct pklcd *lcp;
{
	register struct socket *so = lcp->lcd_so;
	register struct pklcd *l, *p;

	switch (lcp->lcd_state) {
	case LISTEN:
		for (p = 0, l = pk_listenhead; l && l != lcp; p = l, l = l->lcd_listen);
		if (p == 0) {
			if (l != 0)
				pk_listenhead = l->lcd_listen;
		} else if (l != 0)
			p->lcd_listen = l->lcd_listen;
		pk_close(lcp);
		break;

	case READY:
		pk_acct(lcp);
		pk_close(lcp);
		break;

	case SENT_CLEAR:
	case RECEIVED_CLEAR:
		break;

	default:
		pk_acct(lcp);
		if (so) {
			soisdisconnecting(so);
			sbflush(&so->so_rcv);
		}
		pk_clear(lcp, 241, 0);	/* Normal Disconnect */

	}
}

/*
 * Close an X.25 Logical Channel. Discard all space held by the connection
 * and internal descriptors. Wake up any sleepers.
 */

void
pk_close(lcp)
	struct pklcd   *lcp;
{
	register struct socket *so = lcp->lcd_so;

	/*
	 * If the X.25 connection is torn down due to link
	 * level failure (e.g. LLC2 FRMR) and at the same the user
	 * level is still filling up the socket send buffer that
	 * send buffer is locked. An attempt to sbflush () that send
	 * buffer will lead us into - no, not temptation but - panic!
	 * So - we'll just check wether the send buffer is locked
	 * and if that's the case we'll mark the lcp as zombie and
	 * have the pk_timer () do the cleaning ...
	 */

	if (so && so->so_snd.sb_flags & SB_LOCK)
		lcp->lcd_state = LCN_ZOMBIE;
	else
		pk_freelcd(lcp);

	if (so == NULL)
		return;

	so->so_pcb = 0;
	soisdisconnected(so);
#if 0
	sofree (so);	/* gak!!! you can't do that here */
#endif
}

/*
 * Create a template to be used to send X.25 packets on a logical channel. It
 * allocates an mbuf and fills in a skeletal packet depending on its type.
 * This packet is passed to pk_output where the remainer of the packet is
 * filled in.
 */

struct mbuf *
pk_template(lcn, type)
	int             lcn, type;
{
	register struct mbuf *m;
	register struct x25_packet *xp;

	MGETHDR(m, M_DONTWAIT, MT_HEADER);
	if (m == 0)
		panic("pk_template");
	m->m_act = 0;

	/*
	 * Efficiency hack: leave a four byte gap at the beginning
	 * of the packet level header with the hope that this will
	 * be enough room for the link level to insert its header.
	 */
	m->m_data += max_linkhdr;
	m->m_pkthdr.len = m->m_len = PKHEADERLN;

	xp = mtod(m, struct x25_packet *);
	*(long *) xp = 0;	/* ugly, but fast */
	/* xp->q_bit = 0; */
	X25SBITS(xp->bits, fmt_identifier, 1);
	/* xp->lc_group_number = 0; */

	SET_LCN(xp, lcn);
	xp->packet_type = type;

	return (m);
}

/*
 * This routine restarts all the virtual circuits. Actually, the virtual
 * circuits are not "restarted" as such. Instead, any active switched circuit
 * is simply returned to READY state.
 */

void
pk_restart(pkp, restart_cause)
	register struct pkcb *pkp;
	int             restart_cause;
{
	register struct mbuf *m;
	register struct pklcd *lcp;
	register int    i;

	/* Restart all logical channels. */
	if (pkp->pk_chan == 0)
		return;

	/*
	 * Don't do this if we're doing a restart issued from
	 * inside pk_connect () --- which is only done if and
	 * only if the X.25 link is down, i.e. a RESTART needs
	 * to be done to get it up.
	 */
	if (!(pkp->pk_dxerole & DTE_CONNECTPENDING)) {
		for (i = 1; i <= pkp->pk_maxlcn; ++i)
			if ((lcp = pkp->pk_chan[i]) != NULL) {
				if (lcp->lcd_so) {
					lcp->lcd_so->so_error = ENETRESET;
					pk_close(lcp);
				} else {
					pk_flush(lcp);
					lcp->lcd_state = READY;
					if (lcp->lcd_upper)
						(*lcp->lcd_upper)(NULL, lcp);
				}
			}
	}
	if (restart_cause < 0)
		return;

	pkp->pk_state = DTE_SENT_RESTART;
	pkp->pk_dxerole &= ~(DTE_PLAYDCE | DTE_PLAYDTE);
	lcp = pkp->pk_chan[0];
	m = lcp->lcd_template = pk_template(lcp->lcd_lcn, X25_RESTART);
	m->m_pkthdr.len = m->m_len += 2;
	mtod(m, struct x25_packet *)->packet_data = 0;	/* DTE only */
	mtod(m, octet *)[4] = restart_cause;
	pk_output(lcp);
}


/*
 * This procedure frees up the Logical Channel Descripter.
 */

void
pk_freelcd(lcp)
	register struct pklcd *lcp;
{
	if (lcp == NULL)
		return;

	if (lcp->lcd_lcn > 0)
		lcp->lcd_pkp->pk_chan[lcp->lcd_lcn] = NULL;

	pk_flush(lcp);
	remque(&lcp->lcd_q);
	free((caddr_t) lcp, M_PCB);
}

static struct x25_ifaddr *
pk_ifwithaddr(sx)
	struct sockaddr_x25 *sx;
{
	struct ifnet   *ifp;
	struct ifaddr  *ifa;
	register struct x25_ifaddr *ia;
	char           *addr = sx->x25_addr;

	for (ifp = ifnet.tqh_first; ifp != 0; ifp = ifp->if_list.tqe_next)
		for (ifa = ifp->if_addrlist.tqh_first; ifa != 0;
		     ifa = ifa->ifa_list.tqe_next)
			if (ifa->ifa_addr->sa_family == AF_CCITT) {
				ia = (struct x25_ifaddr *) ifa;
				if (bcmp(addr, ia->ia_xc.xc_addr.x25_addr,
					 16) == 0)
					return (ia);

			}
	return ((struct x25_ifaddr *) 0);
}


/*
 * Bind a address and protocol value to a socket.  The important part is the
 * protocol value - the first four characters of the Call User Data field.
 */

#define XTRACTPKP(rt)	((rt)->rt_flags & RTF_GATEWAY ? \
			 ((rt)->rt_llinfo ? \
			  (struct pkcb *) ((struct rtentry *)((rt)->rt_llinfo))->rt_llinfo : \
			  (struct pkcb *) NULL) : \
			 (struct pkcb *)((rt)->rt_llinfo))

int
pk_bind(lcp, nam)
	struct pklcd   *lcp;
	struct mbuf    *nam;
{
	register struct pklcd *pp;
	register struct sockaddr_x25 *sa;

	if (nam == NULL)
		return (EADDRNOTAVAIL);
	if (lcp->lcd_ceaddr)	/* XXX */
		return (EADDRINUSE);
	if (pk_checksockaddr(nam))
		return (EINVAL);
	sa = mtod(nam, struct sockaddr_x25 *);

	/*
	 * If the user wishes to accept calls only from a particular
	 * net (net != 0), make sure the net is known
	 */

	if (sa->x25_addr[0]) {
		if (!pk_ifwithaddr(sa))
			return (ENETUNREACH);
	} else if (sa->x25_net) {
		if (!ifa_ifwithnet((struct sockaddr *) sa))
			return (ENETUNREACH);
	}
	/*
	 * For ISO's sake permit default listeners, but only one such . . .
	 */
	for (pp = pk_listenhead; pp; pp = pp->lcd_listen) {
		register struct sockaddr_x25 *sa2 = pp->lcd_ceaddr;
		if ((sa2->x25_udlen == sa->x25_udlen) &&
		    (sa2->x25_udlen == 0 ||
		     (bcmp(sa2->x25_udata, sa->x25_udata,
			   min(sa2->x25_udlen, sa->x25_udlen)) == 0)))
			return (EADDRINUSE);
	}
	lcp->lcd_laddr = *sa;
	lcp->lcd_ceaddr = &lcp->lcd_laddr;
	return (0);
}

/*
 * Include a bound control block in the list of listeners.
 */
int
pk_listen(lcp)
	register struct pklcd *lcp;
{
	register struct pklcd **pp;

	if (lcp->lcd_ceaddr == 0)
		return (EDESTADDRREQ);

	lcp->lcd_state = LISTEN;
	/*
	 * Add default listener at end, any others at start.
	 */
	if (lcp->lcd_ceaddr->x25_udlen == 0) {
		for (pp = &pk_listenhead; *pp;)
			pp = &((*pp)->lcd_listen);
		*pp = lcp;
	} else {
		lcp->lcd_listen = pk_listenhead;
		pk_listenhead = lcp;
	}
	return (0);
}

/*
 * Include a listening control block for the benefit of other protocols.
 */
int
pk_protolisten(spi, spilen, callee)
	int		spi;
	int		spilen;
	int             (*callee)(struct mbuf *, void *);
{
	register struct pklcd *lcp = pk_attach((struct socket *) 0);
	register struct mbuf *nam;
	register struct sockaddr_x25 *sa;
	int             error = ENOBUFS;

	if (lcp) {
		if ((nam = m_getclr(M_DONTWAIT, MT_SONAME)) != NULL) {
			sa = mtod(nam, struct sockaddr_x25 *);
			sa->x25_family = AF_CCITT;
			sa->x25_len = nam->m_len = sizeof(*sa);
			sa->x25_udlen = spilen;
			sa->x25_udata[0] = spi;
			lcp->lcd_upper = callee;
			lcp->lcd_flags = X25_MBS_HOLD;
			if ((error = pk_bind(lcp, nam)) == 0)
				error = pk_listen(lcp);
			(void) m_free(nam);
		}
		if (error)
			pk_freelcd(lcp);
	}
	return error;		/* Hopefully Zero ! */
}

/*
 * Associate a logical channel descriptor with a network.
 * Fill in the default network specific parameters and then
 * set any parameters explicitly specified by the user or
 * by the remote DTE.
 */

void
pk_assoc(pkp, lcp, sa)
	register struct pkcb *pkp;
	register struct pklcd *lcp;
	register struct sockaddr_x25 *sa;
{

	lcp->lcd_pkp = pkp;
	lcp->lcd_packetsize = pkp->pk_xcp->xc_psize;
	lcp->lcd_windowsize = pkp->pk_xcp->xc_pwsize;
	lcp->lcd_rsn = MODULUS - 1;
	pkp->pk_chan[lcp->lcd_lcn] = lcp;

	if (sa->x25_opts.op_psize)
		lcp->lcd_packetsize = sa->x25_opts.op_psize;
	else
		sa->x25_opts.op_psize = lcp->lcd_packetsize;
	if (sa->x25_opts.op_wsize)
		lcp->lcd_windowsize = sa->x25_opts.op_wsize;
	else
		sa->x25_opts.op_wsize = lcp->lcd_windowsize;
	sa->x25_net = pkp->pk_xcp->xc_addr.x25_net;
	lcp->lcd_flags |= sa->x25_opts.op_flags;
	lcp->lcd_stime = time.tv_sec;
}

int
pk_connect(lcp, sa)
	register struct pklcd *lcp;
	register struct sockaddr_x25 *sa;
{
	register struct pkcb *pkp;
	register struct rtentry *rt;
	register struct rtentry *nrt;

	if (sa->x25_addr[0] == '\0')
		return (EDESTADDRREQ);

	/*
	 * Is the destination address known?
	 */
	if (!(rt = rtalloc1((struct sockaddr *) sa, 1)))
		return (ENETUNREACH);

	if (!(pkp = XTRACTPKP(rt)))
		pkp = pk_newlink((struct x25_ifaddr *) (rt->rt_ifa),
				 (caddr_t) 0);

	/*
	 * Have we entered the LLC address?
	 */
	if ((nrt = npaidb_enter((struct sockaddr_dl *) rt->rt_gateway,
				rt_key(rt), rt, 0)) != NULL)
		pkp->pk_llrt = nrt;

	/*
	 * Have we allocated an LLC2 link yet?
	 */
	if (pkp->pk_llnext == (caddr_t) 0 && pkp->pk_llctlinput) {
		struct dll_ctlinfo ctlinfo;

		ctlinfo.dlcti_rt = rt;
		ctlinfo.dlcti_pcb = (caddr_t) pkp;
		ctlinfo.dlcti_conf =
			(struct dllconfig *) (&((struct x25_ifaddr *) (rt->rt_ifa))->ia_xc);
		pkp->pk_llnext =
			(*pkp->pk_llctlinput)(PRC_CONNECT_REQUEST,
					      NULL, &ctlinfo);
	}
	if (pkp->pk_state != DTE_READY && pkp->pk_state != DTE_WAITING)
		return (ENETDOWN);
	if ((lcp->lcd_lcn = pk_getlcn(pkp)) == 0)
		return (EMFILE);

	lcp->lcd_faddr = *sa;
	lcp->lcd_ceaddr = &lcp->lcd_faddr;
	pk_assoc(pkp, lcp, lcp->lcd_ceaddr);

	/*
	 * If the link is not up yet, initiate an X.25 RESTART
	 */
	if (pkp->pk_state == DTE_WAITING) {
		pkp->pk_dxerole |= DTE_CONNECTPENDING;
		pk_ctlinput(PRC_LINKUP, NULL, pkp);
		if (lcp->lcd_so)
			soisconnecting(lcp->lcd_so);
		return 0;
	}
	if (lcp->lcd_so)
		soisconnecting(lcp->lcd_so);
	lcp->lcd_template = pk_template(lcp->lcd_lcn, X25_CALL);
	pk_callrequest(lcp, lcp->lcd_ceaddr, pkp->pk_xcp);
	return (*pkp->pk_ia->ia_start) (lcp);
}

/*
 * Complete all pending X.25 call requests --- this gets called after
 * the X.25 link has been restarted.
 */
#define RESHUFFLELCN(maxlcn, lcn) ((maxlcn) - (lcn) + 1)

void
pk_callcomplete(pkp)
	register struct pkcb *pkp;
{
	register struct pklcd *lcp;
	register int    i;
	register int    ni;


	if (pkp->pk_dxerole & DTE_CONNECTPENDING)
		pkp->pk_dxerole &= ~DTE_CONNECTPENDING;
	else
		return;

	if (pkp->pk_chan == 0)
		return;

	/*
	 * We pretended to be a DTE for allocating lcns, if
	 * it turns out that we are in reality performing as a
	 * DCE we need to reshuffle the lcps.
	 *
         *             /+---------------+--------     -
	 *            / | a  (maxlcn-1) |              \
	 *           /  +---------------+              	\
	 *     +--- *   | b  (maxlcn-2) |         	 \
	 *     |     \  +---------------+         	  \
	 *   r |      \ | c  (maxlcn-3) |         	   \
	 *   e |       \+---------------+         	    |
	 *   s |        |	 .                	    |
	 *   h |        |        .                	    | m
	 *   u |        |	 .      	  	    | a
	 *   f |        |	 .      	  	    | x
	 *   f |        |	 .                	    | l
	 *   l |       /+---------------+         	    | c
	 *   e |      / | c' (   3    ) |         	    | n
	 *     |     /  +---------------+         	    |
	 *     +--> *   | b' (   2    ) |         	   /
	 *           \  +---------------+         	  /
	 *            \ | a' (   1    ) |         	 /
    	 *             \+---------------+               /
         *              | 0             |              /
	 *              +---------------+--------     -
	 *
	 */
	if (pkp->pk_dxerole & DTE_PLAYDCE) {
		/* Sigh, reshuffle it */
		for (i = pkp->pk_maxlcn; i > 0; --i)
			if (pkp->pk_chan[i]) {
				ni = RESHUFFLELCN(pkp->pk_maxlcn, i);
				pkp->pk_chan[ni] = pkp->pk_chan[i];
				pkp->pk_chan[i] = NULL;
				pkp->pk_chan[ni]->lcd_lcn = ni;
			}
	}
	for (i = 1; i <= pkp->pk_maxlcn; ++i)
		if ((lcp = pkp->pk_chan[i]) != NULL) {
			/*
			 * if (lcp->lcd_so) soisconnecting (lcp->lcd_so);
			 */
			lcp->lcd_template = pk_template(lcp->lcd_lcn, X25_CALL);
			pk_callrequest(lcp, lcp->lcd_ceaddr, pkp->pk_xcp);
			(*pkp->pk_ia->ia_start) (lcp);
		}
}

struct bcdinfo {
	octet          *cp;
	unsigned        posn;
};

/*
 * Build the rest of the CALL REQUEST packet. Fill in calling address,
 * facilities fields and the user data field.
 */

void
pk_callrequest(lcp, sa, xcp)
	struct pklcd   *lcp;
	register struct sockaddr_x25 *sa;
	register struct x25config *xcp;
{
	register struct x25_calladdr *a;
	register struct mbuf *m = lcp->lcd_template;
	register struct x25_packet *xp = mtod(m, struct x25_packet *);
	struct bcdinfo  b;

	if (lcp->lcd_flags & X25_DBIT)
		X25SBITS(xp->bits, d_bit, 1);
	a = (struct x25_calladdr *) & xp->packet_data;
	b.cp = (octet *) a->address_field;
	b.posn = 0;
	X25SBITS(a->addrlens, called_addrlen, to_bcd(&b, sa, xcp));
	X25SBITS(a->addrlens, calling_addrlen, to_bcd(&b, &xcp->xc_addr, xcp));
	if (b.posn & 0x01)
		*b.cp++ &= 0xf0;
	m->m_pkthdr.len = m->m_len += b.cp - (octet *) a;

	if (lcp->lcd_facilities) {
		m->m_pkthdr.len +=
			(m->m_next = lcp->lcd_facilities)->m_pkthdr.len;
		lcp->lcd_facilities = 0;
	} else
		pk_build_facilities(m, sa, (int) xcp->xc_type);

	m_copyback(m, m->m_pkthdr.len, sa->x25_udlen, sa->x25_udata);
}

void
pk_build_facilities(m, sa, type)
	register struct mbuf *m;
	struct sockaddr_x25 *sa;
	int type;
{
	register octet *cp;
	register octet *fcp;
	register int    revcharge;

	cp = mtod(m, octet *) + m->m_len;
	fcp = cp + 1;
	revcharge = sa->x25_opts.op_flags & X25_REVERSE_CHARGE ? 1 : 0;
	/*
	 * This is specific to Datapac X.25(1976) DTEs.  International
	 * calls must have the "hi priority" bit on.
	 */
	if (type == X25_1976 && sa->x25_opts.op_psize == X25_PS128)
		revcharge |= 02;
	if (revcharge) {
		*fcp++ = FACILITIES_REVERSE_CHARGE;
		*fcp++ = revcharge;
	}
	switch (type) {
	case X25_1980:
	case X25_1984:
		*fcp++ = FACILITIES_PACKETSIZE;
		*fcp++ = sa->x25_opts.op_psize;
		*fcp++ = sa->x25_opts.op_psize;

		*fcp++ = FACILITIES_WINDOWSIZE;
		*fcp++ = sa->x25_opts.op_wsize;
		*fcp++ = sa->x25_opts.op_wsize;
	}
	*cp = fcp - cp - 1;
	m->m_pkthdr.len = (m->m_len += *cp + 1);
}

int
to_bcd(b, sa, xcp)
	register struct bcdinfo *b;
	struct sockaddr_x25 *sa;
	register struct x25config *xcp;
{
	register char  *x = sa->x25_addr;
	unsigned        start = b->posn;
	/*
	 * The nodnic and prepnd0 stuff looks tedious,
	 * but it does allow full X.121 addresses to be used,
	 * which is handy for routing info (& OSI type 37 addresses).
	 */
	if (xcp->xc_addr.x25_net && (xcp->xc_nodnic || xcp->xc_prepnd0)) {
		char            dnicname[sizeof(long) * NBBY / 3 + 2];
		register char  *p = dnicname;

		sprintf(p, "%d", xcp->xc_addr.x25_net & 0x7fff);
		for (; *p; p++)	/* *p == 0 means dnic matched */
			if ((*p ^ *x++) & 0x0f)
				break;
		if (*p || xcp->xc_nodnic == 0)
			x = sa->x25_addr;
		if (*p && xcp->xc_prepnd0) {
			if ((b->posn)++ & 0x01)
				(b->cp)++;
			else
				*(b->cp) = 0;
		}
	}
	while (*x)
		if ((b->posn)++ & 0x01)
			*(b->cp)++ |= *x++ & 0x0F;
		else
			*(b->cp) = *x++ << 4;
	return ((b->posn) - start);
}

/*
 * This routine gets the  first available logical channel number.  The search
 * is - from the highest number to lowest number if playing DTE, and - from
 * lowest to highest number if playing DCE.
 */

int
pk_getlcn(pkp)
	register struct pkcb *pkp;
{
	register int    i;

	if (pkp->pk_chan == 0)
		return (0);
	if (pkp->pk_dxerole & DTE_PLAYDCE) {
		for (i = 1; i <= pkp->pk_maxlcn; ++i)
			if (pkp->pk_chan[i] == NULL)
				break;
	} else {
		for (i = pkp->pk_maxlcn; i > 0; --i)
			if (pkp->pk_chan[i] == NULL)
				break;
	}
	i = (i > pkp->pk_maxlcn ? 0 : i);
	return (i);
}

/*
 * This procedure sends a CLEAR request packet. The lc state is set to
 * "SENT_CLEAR".
 */

void
pk_clear(lcp, diagnostic, abortive)
	register struct pklcd *lcp;
	int diagnostic;
	int abortive;
{
	register struct mbuf *m = pk_template(lcp->lcd_lcn, X25_CLEAR);

	m->m_len += 2;
	m->m_pkthdr.len += 2;
	mtod(m, struct x25_packet *)->packet_data = 0;
	mtod(m, octet *)[4] = diagnostic;
	if (lcp->lcd_facilities) {
		m->m_next = lcp->lcd_facilities;
		m->m_pkthdr.len += m->m_next->m_len;
		lcp->lcd_facilities = 0;
	}
	if (abortive)
		lcp->lcd_template = m;
	else {
		struct socket  *so = lcp->lcd_so;
		struct sockbuf *sb = so ? &so->so_snd : &lcp->lcd_sb;
		sbappendrecord(sb, m);
	}
	pk_output(lcp);

}

/*
 * This procedure generates RNR's or RR's to inhibit or enable
 * inward data flow, if the current state changes (blocked ==> open or
 * vice versa), or if forced to generate one.  One forces RNR's to ack data.
 */
void
pk_flowcontrol(lcp, inhibit, forced)
	register struct pklcd *lcp;
	int inhibit;
	int forced;
{
	inhibit = (inhibit != 0);
	if (lcp == 0 || lcp->lcd_state != DATA_TRANSFER ||
	    (forced == 0 && lcp->lcd_rxrnr_condition == inhibit))
		return;
	lcp->lcd_rxrnr_condition = inhibit;
	lcp->lcd_template =
		pk_template(lcp->lcd_lcn, inhibit ? X25_RNR : X25_RR);
	pk_output(lcp);
}

/*
 * This procedure sends a RESET request packet. It re-initializes virtual
 * circuit.
 */

static void
pk_reset(lcp, diagnostic)
	register struct pklcd *lcp;
	int diagnostic;
{
	register struct mbuf *m;
	register struct socket *so = lcp->lcd_so;

	if (lcp->lcd_state != DATA_TRANSFER)
		return;

	if (so)
		so->so_error = ECONNRESET;
	lcp->lcd_reset_condition = TRUE;

	/* Reset all the control variables for the channel. */
	pk_flush(lcp);
	lcp->lcd_window_condition = lcp->lcd_rnr_condition =
		lcp->lcd_intrconf_pending = FALSE;
	lcp->lcd_rsn = MODULUS - 1;
	lcp->lcd_ssn = 0;
	lcp->lcd_output_window = lcp->lcd_input_window =
		lcp->lcd_last_transmitted_pr = 0;
	m = lcp->lcd_template = pk_template(lcp->lcd_lcn, X25_RESET);
	m->m_pkthdr.len = m->m_len += 2;
	mtod(m, struct x25_packet *)->packet_data = 0;
	mtod(m, octet *)[4] = diagnostic;
	pk_output(lcp);

}

/*
 * This procedure frees all data queued for output or delivery on a
 *  virtual circuit.
 */
void
pk_flush(lcp)
	register struct pklcd *lcp;
{
	register struct socket *so;

	if (lcp->lcd_template)
		m_freem(lcp->lcd_template);

	if (lcp->lcd_cps) {
		m_freem(lcp->lcd_cps);
		lcp->lcd_cps = 0;
	}
	if (lcp->lcd_facilities) {
		m_freem(lcp->lcd_facilities);
		lcp->lcd_facilities = 0;
	}
	if ((so = lcp->lcd_so) != NULL)
		sbflush(&so->so_snd);
	else
		sbflush(&lcp->lcd_sb);
}

/*
 * This procedure handles all local protocol procedure errors.
 */

void
pk_procerror(error, lcp, errstr, diagnostic)
	int error;
	register struct pklcd *lcp;
	char *errstr;
	int diagnostic;
{

	pk_message(lcp->lcd_lcn, lcp->lcd_pkp->pk_xcp, errstr);

	switch (error) {
	case PK_CLEAR:
		if (lcp->lcd_so) {
			lcp->lcd_so->so_error = ECONNABORTED;
			soisdisconnecting(lcp->lcd_so);
		}
		pk_clear(lcp, diagnostic, 1);
		break;

	case PK_RESET:
		pk_reset(lcp, diagnostic);
	}
}

/*
 * This procedure is called during the DATA TRANSFER state to check and
 * process  the P(R) values  received  in the DATA,  RR OR RNR packets.
 */

int
pk_ack(lcp, pr)
	struct pklcd   *lcp;
	unsigned        pr;
{
	register struct socket *so = lcp->lcd_so;

	if (lcp->lcd_output_window == pr)
		return (PACKET_OK);
	if (lcp->lcd_output_window < lcp->lcd_ssn) {
		if (pr < lcp->lcd_output_window || pr > lcp->lcd_ssn) {
			pk_procerror(PK_RESET, lcp,
				     "p(r) flow control error", 2);
			return (ERROR_PACKET);
		}
	} else {
		if (pr < lcp->lcd_output_window && pr > lcp->lcd_ssn) {
			pk_procerror(PK_RESET, lcp,
				     "p(r) flow control error #2", 2);
			return (ERROR_PACKET);
		}
	}

	lcp->lcd_output_window = pr;	/* Rotate window. */
	if (lcp->lcd_window_condition == TRUE)
		lcp->lcd_window_condition = FALSE;

	if (so && sb_notify(&(so->so_snd)))
		sowwakeup(so);

	return (PACKET_OK);
}

/*
 * This procedure decodes the X.25 level 3 packet returning a code to be used
 * in switchs or arrays.
 */

int
pk_decode(xp)
	register struct x25_packet *xp;
{
	register int    type;

	if (X25GBITS(xp->bits, fmt_identifier) != 1)
		return (PK_INVALID_PACKET);
#ifdef ancient_history
	/*
	 * Make sure that the logical channel group number is 0. This
	 * restriction may be removed at some later date.
	 */
	if (xp->lc_group_number != 0)
		return (PK_INVALID_PACKET);
#endif
	/*
	 * Test for data packet first.
	 */
	if (!(xp->packet_type & DATA_PACKET_DESIGNATOR))
		return (PK_DATA);

	/*
	 * Test if flow control packet (RR or RNR).
	 */
	if (!(xp->packet_type & RR_OR_RNR_PACKET_DESIGNATOR))
		switch (xp->packet_type & 0x1f) {
		case X25_RR:
			return (PK_RR);
		case X25_RNR:
			return (PK_RNR);
		case X25_REJECT:
			return (PK_REJECT);
		}

	/*
	 * Determine the rest of the packet types.
	 */
	switch (xp->packet_type) {
	case X25_CALL:
		type = PK_CALL;
		break;

	case X25_CALL_ACCEPTED:
		type = PK_CALL_ACCEPTED;
		break;

	case X25_CLEAR:
		type = PK_CLEAR;
		break;

	case X25_CLEAR_CONFIRM:
		type = PK_CLEAR_CONF;
		break;

	case X25_INTERRUPT:
		type = PK_INTERRUPT;
		break;

	case X25_INTERRUPT_CONFIRM:
		type = PK_INTERRUPT_CONF;
		break;

	case X25_RESET:
		type = PK_RESET;
		break;

	case X25_RESET_CONFIRM:
		type = PK_RESET_CONF;
		break;

	case X25_RESTART:
		type = PK_RESTART;
		break;

	case X25_RESTART_CONFIRM:
		type = PK_RESTART_CONF;
		break;

	case X25_DIAGNOSTIC:
		type = PK_DIAG_TYPE;
		break;

	default:
		type = PK_INVALID_PACKET;
	}
	return (type);
}

/*
 * A restart packet has been received. Print out the reason for the restart.
 */

void
pk_restartcause(pkp, xp)
	struct pkcb    *pkp;
	register struct x25_packet *xp;
{
	register struct x25config *xcp = pkp->pk_xcp;
	register int    lcn = LCN(xp);

	switch (xp->packet_data) {
	case X25_RESTART_LOCAL_PROCEDURE_ERROR:
		pk_message(lcn, xcp, "restart: local procedure error");
		break;

	case X25_RESTART_NETWORK_CONGESTION:
		pk_message(lcn, xcp, "restart: network congestion");
		break;

	case X25_RESTART_NETWORK_OPERATIONAL:
		pk_message(lcn, xcp, "restart: network operational");
		break;

	default:
		pk_message(lcn, xcp, "restart: unknown cause");
	}
}

#define MAXRESETCAUSE	7

int             Reset_cause[] = {
	EXRESET, EXROUT, 0, EXRRPE, 0, EXRLPE, 0, EXRNCG
};

/*
 * A reset packet has arrived. Return the cause to the user.
 */

void
pk_resetcause(pkp, xp)
	struct pkcb    *pkp;
	register struct x25_packet *xp;
{
	register struct pklcd *lcp =
	pkp->pk_chan[LCN(xp)];
	register int    code = xp->packet_data;

	if (code > MAXRESETCAUSE)
		code = 7;	/* EXRNCG */

	pk_message(LCN(xp), lcp->lcd_pkp->pk_xcp,
		   "reset code 0x%x, diagnostic 0x%x",
		   xp->packet_data, 4[(u_char *) xp]);

	if (lcp->lcd_so)
		lcp->lcd_so->so_error = Reset_cause[code];
}

#define MAXCLEARCAUSE	25

int Clear_cause[] = {
	EXCLEAR, EXCBUSY, 0, EXCINV, 0, EXCNCG, 0,
	0, 0, EXCOUT, 0, EXCAB, 0, EXCNOB, 0, 0, 0, EXCRPE,
	0, EXCLPE, 0, 0, 0, 0, 0, EXCRRC
};

/*
 * A clear packet has arrived. Return the cause to the user.
 */
void
pk_clearcause(pkp, xp)
	struct pkcb    *pkp;
	register struct x25_packet *xp;
{
	register struct pklcd *lcp =
	pkp->pk_chan[LCN(xp)];
	register int    code = xp->packet_data;

	if (code > MAXCLEARCAUSE)
		code = 5;	/* EXRNCG */
	if (lcp->lcd_so)
		lcp->lcd_so->so_error = Clear_cause[code];
}

char *
format_ntn(xcp)
	register struct x25config *xcp;
{

	return (xcp->xc_addr.x25_addr);
}

/* VARARGS1 */
void
pk_message(int lcn, struct x25config * xcp, char * fmt,...)
{
	va_list         ap;

	if (lcn) {
		if (!PQEMPTY)
			printf("X.25(%s): lcn %d: ", format_ntn(xcp), lcn);
		else
			printf("X.25: lcn %d: ", lcn);
	} else if (!PQEMPTY)
		printf("X.25(%s): ", format_ntn(xcp));
	else
		printf("X.25: ");

	va_start(ap, fmt);
	printf("%:\n", fmt, ap);
	va_end(ap);
}

int
pk_fragment(lcp, m0, qbit, mbit, wait)
	struct mbuf    *m0;
	register struct pklcd *lcp;
	int qbit, mbit, wait;
{
	register struct mbuf *m = m0;
	register struct x25_packet *xp;
	register struct sockbuf *sb;
	struct mbuf    *head = 0, *next, **mp = &head;
	int             totlen, psize = 1 << (lcp->lcd_packetsize);

	if (m == 0)
		return 0;
	if ((m->m_flags & M_PKTHDR) == 0)
		panic("pk_fragment");
	totlen = m->m_pkthdr.len;
	m->m_act = 0;
	sb = lcp->lcd_so ? &lcp->lcd_so->so_snd : &lcp->lcd_sb;
	do {
		if (totlen > psize) {
			if ((next = m_split(m, psize, wait)) == 0)
				goto abort;
			totlen -= psize;
		} else
			next = 0;
		M_PREPEND(m, PKHEADERLN, wait);
		if (m == 0)
			goto abort;
		*mp = m;
		mp = &m->m_act;
		*mp = 0;
		xp = mtod(m, struct x25_packet *);
		0[(char *) xp] = 0;
		if (qbit)
			X25SBITS(xp->bits, q_bit, 1);
		if (lcp->lcd_flags & X25_DBIT)
			X25SBITS(xp->bits, d_bit, 1);
		X25SBITS(xp->bits, fmt_identifier, 1);
		xp->packet_type = X25_DATA;
		SET_LCN(xp, lcp->lcd_lcn);
		if (next || (mbit && (totlen == psize ||
				      (lcp->lcd_flags & X25_DBIT))))
			SMBIT(xp, 1);
	} while ((m = next) != NULL);
	for (m = head; m; m = next) {
		next = m->m_act;
		m->m_act = 0;
		sbappendrecord(sb, m);
	}
	return 0;
abort:
	if (wait)
		panic("pk_fragment null mbuf after wait");
	if (next)
		m_freem(next);
	for (m = head; m; m = next) {
		next = m->m_act;
		m_freem(m);
	}
	return ENOBUFS;
}