NetBSD/sys/netccitt/pk_input.c

/*	$NetBSD: pk_input.c,v 1.13 1998/09/13 16:21:19 christos Exp $	*/

/*
 * Copyright (c) 1984 University of British Columbia.
 * Copyright (c) 1992 Computer Science Department IV,
 * 		University of Erlangen-Nuremberg, Germany.
 * 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_input.c	8.1 (Berkeley) 6/10/93
 */

#include "opt_hdlc.h"
#include "opt_llc.h"

#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/proc.h>
#include <sys/errno.h>

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

#include <netccitt/dll.h>
#include <netccitt/x25.h>
#include <netccitt/pk.h>
#include <netccitt/pk_var.h>
#include <netccitt/pk_extern.h>
#include <netccitt/llc_var.h>
#ifdef HDLC
#include <netccitt/hdlc.h>
#include <netccitt/hd_var.h>
#endif

#include <machine/stdarg.h>

struct pkcb_q   pkcb_q = {&pkcb_q, &pkcb_q};

static void prune_dnic __P((char *, char *, char *, struct x25config *));
static void save_extra __P((struct mbuf *, octet *, struct socket *));

/*
 * ccittintr() is the generic interrupt handler for HDLC, LLC2, and X.25. This
 * allows to have kernel running X.25 but no HDLC or LLC2 or both (in case we
 * employ boards that do all the stuff themselves, e.g. ADAX X.25 or TPS ISDN.)
 */
void
ccittintr()
{
	extern struct ifqueue pkintrq;
	extern struct ifqueue hdintrq;
	extern struct ifqueue llcintrq;

#ifdef HDLC
	if (hdintrq.ifq_len)
		hdintr();
#endif
#ifdef LLC
	if (llcintrq.ifq_len)
		llcintr();
#endif
	if (pkintrq.ifq_len)
		pkintr();
}

struct pkcb    *
pk_newlink(ia, llnext)
	struct x25_ifaddr *ia;
	caddr_t         llnext;
{
	register struct x25config *xcp = &ia->ia_xc;
	register struct pkcb *pkp;
	register struct protosw *pp;
	unsigned        size;

	pp = pffindproto(AF_CCITT, (int) xcp->xc_lproto, 0);
	if (pp == 0 || pp->pr_output == 0) {
		pk_message(0, xcp, "link level protosw error");
		return ((struct pkcb *) 0);
	}
	/*
	 * Allocate a network control block structure
	 */
	size = sizeof(struct pkcb);
	pkp = (struct pkcb *) malloc(size, M_PCB, M_WAITOK);
	if (pkp == 0)
		return ((struct pkcb *) 0);
	bzero((caddr_t) pkp, size);
	pkp->pk_lloutput = pp->pr_output;
	pkp->pk_llctlinput = pp->pr_ctlinput;
	pkp->pk_xcp = xcp;
	pkp->pk_ia = ia;
	pkp->pk_state = DTE_WAITING;
	pkp->pk_llnext = llnext;
	insque(pkp, &pkcb_q);

	/*
	 * set defaults
	 */

	if (xcp->xc_pwsize == 0)
		xcp->xc_pwsize = DEFAULT_WINDOW_SIZE;
	if (xcp->xc_psize == 0)
		xcp->xc_psize = X25_PS128;
	/*
	 * Allocate logical channel descriptor vector
	 */

	(void) pk_resize(pkp);
	return (pkp);
}


int
pk_dellink(pkp)
	register struct pkcb *pkp;
{
	register int    i;
	register struct protosw *pp;

	/*
	 * Essentially we have the choice to
	 * (a) go ahead and let the route be deleted and
	 *     leave the pkcb associated with that route
	 *     as it is, i.e. the connections stay open
	 * (b) do a pk_disconnect() on all channels associated
	 *     with the route via the pkcb and then proceed.
	 *
	 * For the time being we stick with (b)
	 */

	for (i = 1; i < pkp->pk_maxlcn; ++i)
		if (pkp->pk_chan[i])
			pk_disconnect(pkp->pk_chan[i]);

	/*
	 * Free the pkcb
	 */

	/*
	 * First find the protoswitch to get hold of the link level
	 * protocol to be notified that the packet level entity is
	 * dissolving ...
	 */
	pp = pffindproto(AF_CCITT, (int) pkp->pk_xcp->xc_lproto, 0);
	if (pp == 0 || pp->pr_output == 0) {
		pk_message(0, pkp->pk_xcp, "link level protosw error");
		return (EPROTONOSUPPORT);
	}
	pkp->pk_refcount--;
	if (!pkp->pk_refcount) {
		struct dll_ctlinfo ctlinfo;

		remque(pkp);
		if (pkp->pk_rt->rt_llinfo == (caddr_t) pkp)
			pkp->pk_rt->rt_llinfo = (caddr_t) NULL;

		/*
		 * Tell the link level that the pkcb is dissolving
		 */
		if (pp->pr_ctlinput && pkp->pk_llnext) {
			ctlinfo.dlcti_pcb = pkp->pk_llnext;
			ctlinfo.dlcti_rt = pkp->pk_rt;
			(*pp->pr_ctlinput) (PRC_DISCONNECT_REQUEST,
					    (struct sockaddr *)pkp->pk_xcp,
					    &ctlinfo);
		}
		free((caddr_t) pkp->pk_chan, M_IFADDR);
		free((caddr_t) pkp, M_PCB);
	}
	return (0);
}


int
pk_resize(pkp)
	register struct pkcb *pkp;
{
	struct pklcd   *dev_lcp = 0;
	struct x25config *xcp = pkp->pk_xcp;
	if (pkp->pk_chan &&
	    (pkp->pk_maxlcn != xcp->xc_maxlcn)) {
		pk_restart(pkp, X25_RESTART_NETWORK_CONGESTION);
		dev_lcp = pkp->pk_chan[0];
		free((caddr_t) pkp->pk_chan, M_IFADDR);
		pkp->pk_chan = 0;
	}
	if (pkp->pk_chan == 0) {
		unsigned        size;
		pkp->pk_maxlcn = xcp->xc_maxlcn;
		size = (pkp->pk_maxlcn + 1) * sizeof(struct pklcd *);
		pkp->pk_chan = malloc(size, M_IFADDR, M_WAITOK);
		if (pkp->pk_chan) {
			bzero((caddr_t) pkp->pk_chan, size);
			/*
			 * Allocate a logical channel descriptor for lcn 0
			 */
			if (dev_lcp == 0 &&
			    (dev_lcp = pk_attach((struct socket *) 0)) == 0)
				return (ENOBUFS);
			dev_lcp->lcd_state = READY;
			dev_lcp->lcd_pkp = pkp;
			pkp->pk_chan[0] = dev_lcp;
		} else {
			if (dev_lcp)
				pk_close(dev_lcp);
			return (ENOBUFS);
		}
	}
	return 0;
}

/*
 * This procedure is called by the link level whenever the link becomes
 * operational, is reset, or when the link goes down.
 */
/* VARARGS */
void *
pk_ctlinput(code, src, addr)
	int             code;
	struct sockaddr *src;
	void            *addr;
{
	register struct pkcb *pkp = (struct pkcb *) addr;
	struct rtentry *llrt;

	switch (code) {
	case PRC_LINKUP:
		if (pkp->pk_state == DTE_WAITING)
			pk_restart(pkp, X25_RESTART_NETWORK_CONGESTION);
		break;

	case PRC_LINKDOWN:
		pk_restart(pkp, -1);	/* Clear all active circuits */
		pkp->pk_state = DTE_WAITING;
		break;

	case PRC_LINKRESET:
		pk_restart(pkp, X25_RESTART_NETWORK_CONGESTION);
		break;

	case PRC_CONNECT_INDICATION:

		if ((llrt = rtalloc1(src, 0)) == 0)
			return 0;
		else
			llrt->rt_refcnt--;

		pkp = (((struct npaidbentry *) llrt->rt_llinfo)->np_rt) ?
			(struct pkcb *) (((struct npaidbentry *) llrt->rt_llinfo)->np_rt->rt_llinfo) : (struct pkcb *) 0;
		if (pkp == (struct pkcb *) 0)
			return 0;
		pkp->pk_llnext = addr;

		return ((caddr_t) pkp);

	case PRC_DISCONNECT_INDICATION:
		pk_restart(pkp, -1);	/* Clear all active circuits */
		pkp->pk_state = DTE_WAITING;
		pkp->pk_llnext = (caddr_t) 0;
		break;
	}
	return (0);
}
struct ifqueue  pkintrq;
/*
 * This routine is called if there are semi-smart devices that do HDLC
 * in hardware and want to queue the packet and call level 3 directly
 */
void
pkintr()
{
	register struct mbuf *m;
	register int    s;

	for (;;) {
		s = splimp();
		IF_DEQUEUE(&pkintrq, m);
		splx(s);
		if (m == 0)
			break;
		if (m->m_len < PKHEADERLN) {
			printf("pkintr: packet too short (len=%d)\n",
			    m->m_len);
			m_freem(m);
			continue;
		}
		pk_input(m);
	}
}

struct mbuf    *pk_bad_packet;
struct mbuf_cache pk_input_cache = {0};
/*
 * X.25 PACKET INPUT
 * 
 * This procedure is called by a link level procedure whenever an information
 * frame is received. It decodes the packet and demultiplexes based on the
 * logical channel number.
 * 
 * We change the original conventions of the UBC code here -- since there may be
 * multiple pkcb's for a given interface of type 802.2 class 2, we retrieve
 * which one it is from m_pkthdr.rcvif (which has been overwritten by lower
 * layers); That field is then restored for the benefit of upper layers which
 * may make use of it, such as CLNP.
 * 
 */

#define RESTART_DTE_ORIGINATED(xp) \
	(((xp)->packet_cause == X25_RESTART_DTE_ORIGINATED) || \
	 ((xp)->packet_cause >= X25_RESTART_DTE_ORIGINATED2))

void
#if __STDC__
pk_input(struct mbuf *m, ...)
#else
pk_input(m, va_alist)
	struct mbuf *m;
	va_dcl
#endif
{
	register struct x25_packet *xp;
	register struct pklcd *lcp;
	register struct socket *so = 0;
	register struct pkcb *pkp;
	int             ptype, lcn, lcdstate = LISTEN;

	if (pk_input_cache.mbc_size || pk_input_cache.mbc_oldsize)
		mbuf_cache(&pk_input_cache, m);
	if ((m->m_flags & M_PKTHDR) == 0)
		panic("pkintr");

	if ((pkp = (struct pkcb *) m->m_pkthdr.rcvif) == 0)
		return;
	xp = mtod(m, struct x25_packet *);
	ptype = pk_decode(xp);
	lcn = LCN(xp);
	lcp = pkp->pk_chan[lcn];

	/*
	 * If the DTE is in Restart  state, then it will ignore data,
	 * interrupt, call setup and clearing, flow control and reset
	 * packets.
	 */
	if (lcn < 0 || lcn > pkp->pk_maxlcn) {
		pk_message(lcn, pkp->pk_xcp, "illegal lcn");
		m_freem(m);
		return;
	}
	pk_trace(pkp->pk_xcp, m, "P-In");

	if (pkp->pk_state != DTE_READY && ptype != PK_RESTART &&
	    ptype != PK_RESTART_CONF) {
		m_freem(m);
		return;
	}
	if (lcp) {
		so = lcp->lcd_so;
		lcdstate = lcp->lcd_state;
	} else {
		if (ptype == PK_CLEAR) {/* idle line probe (Datapac specific) */
			/* send response on lcd 0's output queue */
			lcp = pkp->pk_chan[0];
			lcp->lcd_template = pk_template(lcn, X25_CLEAR_CONFIRM);
			pk_output(lcp);
			m_freem(m);
			return;
		}
		if (ptype != PK_CALL)
			ptype = PK_INVALID_PACKET;
	}

	if (lcn == 0 && ptype != PK_RESTART && ptype != PK_RESTART_CONF) {
		pk_message(0, pkp->pk_xcp, "illegal ptype (%d, %s) on lcn 0",
			   ptype, pk_name[ptype / MAXSTATES]);
		if (pk_bad_packet)
			m_freem(pk_bad_packet);
		pk_bad_packet = m;
		return;
	}
	m->m_pkthdr.rcvif = pkp->pk_ia->ia_ifp;

	switch (ptype + lcdstate) {
		/*
		 * Incoming Call packet received.
		 */
	case PK_CALL + LISTEN:
		pk_incoming_call(pkp, m);
		break;

		/*
		 * Call collision: Just throw this "incoming call" away since
		 * the DCE will ignore it anyway.
		 */
	case PK_CALL + SENT_CALL:
		pk_message((int) lcn, pkp->pk_xcp,
			   "incoming call collision");
		break;

		/*
		 * Call confirmation packet received. This usually means our
		 * previous connect request is now complete.
		 */
	case PK_CALL_ACCEPTED + SENT_CALL:
		MCHTYPE(m, MT_CONTROL);
		pk_call_accepted(lcp, m);
		break;

		/*
		 * This condition can only happen if the previous state was
		 * SENT_CALL. Just ignore the packet, eventually a clear
		 * confirmation should arrive.
		 */
	case PK_CALL_ACCEPTED + SENT_CLEAR:
		break;

		/*
		 * Clear packet received. This requires a complete tear down
		 * of the virtual circuit.  Free buffers and control blocks.
		 * and send a clear confirmation.
		 */
	case PK_CLEAR + READY:
	case PK_CLEAR + RECEIVED_CALL:
	case PK_CLEAR + SENT_CALL:
	case PK_CLEAR + DATA_TRANSFER:
		lcp->lcd_state = RECEIVED_CLEAR;
		lcp->lcd_template = pk_template(lcp->lcd_lcn, X25_CLEAR_CONFIRM);
		pk_output(lcp);
		pk_clearcause(pkp, xp);
		if (lcp->lcd_upper) {
			MCHTYPE(m, MT_CONTROL);
			(*lcp->lcd_upper)(m, lcp);
		}
		pk_close(lcp);
		lcp = 0;
		break;

		/*
		 * Clear collision: Treat this clear packet as a
		 * confirmation.
		 */
	case PK_CLEAR + SENT_CLEAR:
		pk_close(lcp);
		break;

		/*
		 * Clear confirmation received. This usually means the
		 * virtual circuit is now completely removed.
		 */
	case PK_CLEAR_CONF + SENT_CLEAR:
		pk_close(lcp);
		break;

		/*
		 * A clear confirmation on an unassigned logical channel -
		 * just ignore it. Note: All other packets on an unassigned
		 * channel results in a clear.
		 */
	case PK_CLEAR_CONF + READY:
	case PK_CLEAR_CONF + LISTEN:
		break;

		/*
		 * Data packet received. Pass on to next level. Move the Q
		 * and M bits into the data portion for the next level.
		 */
	case PK_DATA + DATA_TRANSFER:
		if (lcp->lcd_reset_condition) {
			ptype = PK_DELETE_PACKET;
			break;
		}
		/*
		 * Process the P(S) flow control information in this Data
		 * packet. Check that the packets arrive in the correct
		 * sequence and that they are within the "lcd_input_window".
		 * Input window rotation is initiated by the receive
		 * interface.
		 */

		if (PS(xp) != ((lcp->lcd_rsn + 1) % MODULUS) ||
		    PS(xp) == ((lcp->lcd_input_window + lcp->lcd_windowsize) % MODULUS)) {
			m_freem(m);
			pk_procerror(PK_RESET, lcp,
				     "p(s) flow control error", 1);
			break;
		}
		lcp->lcd_rsn = PS(xp);

		if (pk_ack(lcp, PR(xp)) != PACKET_OK) {
			m_freem(m);
			break;
		}
		m->m_data += PKHEADERLN;
		m->m_len -= PKHEADERLN;
		m->m_pkthdr.len -= PKHEADERLN;

		lcp->lcd_rxcnt++;
		if (lcp->lcd_flags & X25_MBS_HOLD) {
			register struct mbuf *n = lcp->lcd_cps;
			int             mbit = MBIT(xp);
			octet           q_and_d_bits;

			if (n) {
				n->m_pkthdr.len += m->m_pkthdr.len;
				while (n->m_next)
					n = n->m_next;
				n->m_next = m;
				m = lcp->lcd_cps;

				if (lcp->lcd_cpsmax &&
				    n->m_pkthdr.len > lcp->lcd_cpsmax) {
					pk_procerror(PK_RESET, lcp,
						     "C.P.S. overflow", 128);
					return;
				}
				q_and_d_bits = 0xc0 & *(octet *) xp;
				xp = (struct x25_packet *)
					(mtod(m, octet *) - PKHEADERLN);
				*(octet *) xp |= q_and_d_bits;
			}
			if (mbit) {
				lcp->lcd_cps = m;
				pk_flowcontrol(lcp, 0, 1);
				return;
			}
			lcp->lcd_cps = 0;
		}
		if (so == 0)
			break;
		if (lcp->lcd_flags & X25_MQBIT) {
			octet t = (X25GBITS(xp->bits, q_bit)) ? t = 0x80 : 0;

			if (MBIT(xp))
				t |= 0x40;
			m->m_data -= 1;
			m->m_len += 1;
			m->m_pkthdr.len += 1;
			*mtod(m, octet *) = t;
		}
		/*
		 * Discard Q-BIT packets if the application
		 * doesn't want to be informed of M and Q bit status
		 */
		if (X25GBITS(xp->bits, q_bit)
		    && (lcp->lcd_flags & X25_MQBIT) == 0) {
			m_freem(m);
			/*
			 * NB.  This is dangerous: sending a RR here can
			 * cause sequence number errors if a previous data
			 * packet has not yet been passed up to the application
			 * (RR's are normally generated via PRU_RCVD).
			 */
			pk_flowcontrol(lcp, 0, 1);
		} else {
			sbappendrecord(&so->so_rcv, m);
			sorwakeup(so);
		}
		break;

		/*
		 * Interrupt packet received.
		 */
	case PK_INTERRUPT + DATA_TRANSFER:
		if (lcp->lcd_reset_condition)
			break;
		lcp->lcd_intrdata = xp->packet_data;
		lcp->lcd_template = pk_template(lcp->lcd_lcn,
						X25_INTERRUPT_CONFIRM);
		pk_output(lcp);
		m->m_data += PKHEADERLN;
		m->m_len -= PKHEADERLN;
		m->m_pkthdr.len -= PKHEADERLN;
		MCHTYPE(m, MT_OOBDATA);
		if (so) {
			if (so->so_options & SO_OOBINLINE)
				sbinsertoob(&so->so_rcv, m);
			else
				m_freem(m);
			sohasoutofband(so);
		}
		break;

		/*
		 * Interrupt confirmation packet received.
		 */
	case PK_INTERRUPT_CONF + DATA_TRANSFER:
		if (lcp->lcd_reset_condition)
			break;
		if (lcp->lcd_intrconf_pending == TRUE)
			lcp->lcd_intrconf_pending = FALSE;
		else
			pk_procerror(PK_RESET, lcp, "unexpected packet", 43);
		break;

		/*
		 * Receiver ready received. Rotate the output window and
		 * output any data packets waiting transmission.
		 */
	case PK_RR + DATA_TRANSFER:
		if (lcp->lcd_reset_condition ||
		    pk_ack(lcp, PR(xp)) != PACKET_OK) {
			ptype = PK_DELETE_PACKET;
			break;
		}
		if (lcp->lcd_rnr_condition == TRUE)
			lcp->lcd_rnr_condition = FALSE;
		pk_output(lcp);
		break;

		/*
		 * Receiver Not Ready received. Packets up to the P(R) can be
		 * be sent. Condition is cleared with a RR.
		 */
	case PK_RNR + DATA_TRANSFER:
		if (lcp->lcd_reset_condition ||
		    pk_ack(lcp, PR(xp)) != PACKET_OK) {
			ptype = PK_DELETE_PACKET;
			break;
		}
		lcp->lcd_rnr_condition = TRUE;
		break;

		/*
		 * Reset packet received. Set state to FLOW_OPEN.  The Input
		 * and Output window edges ar set to zero. Both the send and
		 * receive numbers are reset. A confirmation is returned.
		 */
	case PK_RESET + DATA_TRANSFER:
		if (lcp->lcd_reset_condition)
			/* Reset collision. Just ignore packet. */
			break;

		pk_resetcause(pkp, xp);
		lcp->lcd_window_condition = lcp->lcd_rnr_condition =
			lcp->lcd_intrconf_pending = FALSE;
		lcp->lcd_output_window = lcp->lcd_input_window =
			lcp->lcd_last_transmitted_pr = 0;
		lcp->lcd_ssn = 0;
		lcp->lcd_rsn = MODULUS - 1;

		lcp->lcd_template = pk_template(lcp->lcd_lcn, X25_RESET_CONFIRM);
		pk_output(lcp);

		pk_flush(lcp);
		if (so == 0)
			break;
		wakeup((caddr_t) & so->so_timeo);
		sorwakeup(so);
		sowwakeup(so);
		break;

		/*
		 * Reset confirmation received.
		 */
	case PK_RESET_CONF + DATA_TRANSFER:
		if (lcp->lcd_reset_condition) {
			lcp->lcd_reset_condition = FALSE;
			pk_output(lcp);
		} else
			pk_procerror(PK_RESET, lcp, "unexpected packet", 32);
		break;

	case PK_DATA + SENT_CLEAR:
		ptype = PK_DELETE_PACKET;
	case PK_RR + SENT_CLEAR:
	case PK_RNR + SENT_CLEAR:
	case PK_INTERRUPT + SENT_CLEAR:
	case PK_INTERRUPT_CONF + SENT_CLEAR:
	case PK_RESET + SENT_CLEAR:
	case PK_RESET_CONF + SENT_CLEAR:
		/*
		 * Just ignore p if we have sent a CLEAR already.
		 */
		break;

		/*
		 * Restart sets all the permanent virtual circuits to the
		 * "Data Transfer" stae and  all the switched virtual
		 * circuits to the "Ready" state.
		 */
	case PK_RESTART + READY:
		switch (pkp->pk_state) {
		case DTE_SENT_RESTART:
			/*
			 * Restart collision. If case the restart cause is
			 * "DTE originated" we have a DTE-DTE situation and
			 * are trying to resolve who is going to play DTE/DCE
			 * [ISO 8208:4.2-4.5]
			 */
			if (RESTART_DTE_ORIGINATED(xp)) {
				pk_restart(pkp, X25_RESTART_DTE_ORIGINATED);
				pk_message(0, pkp->pk_xcp,
					   "RESTART collision");
				if ((pkp->pk_restartcolls++) > MAXRESTARTCOLLISIONS) {
					pk_message(0, pkp->pk_xcp,
					    "excessive RESTART collisions");
					pkp->pk_restartcolls = 0;
				}
				break;
			}
			pkp->pk_state = DTE_READY;
			pkp->pk_dxerole |= DTE_PLAYDTE;
			pkp->pk_dxerole &= ~DTE_PLAYDCE;
			pk_message(0, pkp->pk_xcp,
				   "Packet level operational");
			pk_message(0, pkp->pk_xcp,
				   "Assuming DTE role");
			if (pkp->pk_dxerole & DTE_CONNECTPENDING)
				pk_callcomplete(pkp);
			break;

		default:
			pk_restart(pkp, -1);
			pk_restartcause(pkp, xp);
			pkp->pk_chan[0]->lcd_template = pk_template(0,
						       X25_RESTART_CONFIRM);
			pk_output(pkp->pk_chan[0]);
			pkp->pk_state = DTE_READY;
			pkp->pk_dxerole |= RESTART_DTE_ORIGINATED(xp) ? DTE_PLAYDCE :
				DTE_PLAYDTE;
			if (pkp->pk_dxerole & DTE_PLAYDTE) {
				pkp->pk_dxerole &= ~DTE_PLAYDCE;
				pk_message(0, pkp->pk_xcp,
					   "Assuming DTE role");
			} else {
				pkp->pk_dxerole &= ~DTE_PLAYDTE;
				pk_message(0, pkp->pk_xcp,
					   "Assuming DCE role");
			}
			if (pkp->pk_dxerole & DTE_CONNECTPENDING)
				pk_callcomplete(pkp);
		}
		break;

		/*
		 * Restart confirmation received. All logical channels are
		 * set to READY.
		 */
	case PK_RESTART_CONF + READY:
		switch (pkp->pk_state) {
		case DTE_SENT_RESTART:
			pkp->pk_state = DTE_READY;
			pkp->pk_dxerole |= DTE_PLAYDTE;
			pkp->pk_dxerole &= ~DTE_PLAYDCE;
			pk_message(0, pkp->pk_xcp,
				   "Packet level operational");
			pk_message(0, pkp->pk_xcp,
				   "Assuming DTE role");
			if (pkp->pk_dxerole & DTE_CONNECTPENDING)
				pk_callcomplete(pkp);
			break;

		default:
			/* Restart local procedure error. */
			pk_restart(pkp, X25_RESTART_LOCAL_PROCEDURE_ERROR);
			pkp->pk_state = DTE_SENT_RESTART;
			pkp->pk_dxerole &= ~(DTE_PLAYDTE | DTE_PLAYDCE);
		}
		break;

	default:
		if (lcp) {
			pk_procerror(PK_CLEAR, lcp, "unknown packet error", 33);
			pk_message(lcn, pkp->pk_xcp,
				   "\"%s\" unexpected in \"%s\" state",
			    pk_name[ptype / MAXSTATES], pk_state[lcdstate]);
		} else
			pk_message(lcn, pkp->pk_xcp,
				   "packet arrived on unassigned lcn");
		break;
	}
	if (so == 0 && lcp && lcp->lcd_upper && lcdstate == DATA_TRANSFER) {
		if (ptype != PK_DATA && ptype != PK_INTERRUPT)
			MCHTYPE(m, MT_CONTROL);
		lcp->lcd_upper(m, lcp);
	} else if (ptype != PK_DATA && ptype != PK_INTERRUPT)
		m_freem(m);
}

static void
prune_dnic(from, to, dnicname, xcp)
	char           *from, *to, *dnicname;
	register struct x25config *xcp;
{
	register char  *cp1 = from, *cp2 = from;
	if (xcp->xc_prepnd0 && *cp1 == '0') {
		from = ++cp1;
		goto copyrest;
	}
	if (xcp->xc_nodnic) {
		for (cp1 = dnicname; (*cp2 = *cp1++) != '\0';)
			cp2++;
		cp1 = from;
	}
copyrest:
	for (cp1 = dnicname; (*cp2 = *cp1++) != '\0';)
		cp2++;
}

void
pk_simple_bsd(from, to, lower, len)
	register octet *from, *to;
	register int    len, lower;
{
	register int    c;
	while (--len >= 0) {
		c = *from;
		if (lower & 0x01)
			from++;
		else
			c >>= 4;
		c &= 0x0f;
		c |= 0x30;
		*to++ = c;
		lower++;
	}
	*to = 0;
}

void
pk_from_bcd(a, iscalling, sa, xcp)
	register struct x25_calladdr *a;
	int             iscalling;
	register struct sockaddr_x25 *sa;
	register struct x25config *xcp;
{
	octet           buf[MAXADDRLN + 1];
	octet          *cp;
	unsigned        count;

	bzero((caddr_t) sa, sizeof(*sa));
	sa->x25_len = sizeof(*sa);
	sa->x25_family = AF_CCITT;
	if (iscalling) {
		cp = a->address_field + (X25GBITS(a->addrlens, called_addrlen) / 2);
		count = X25GBITS(a->addrlens, calling_addrlen);
		pk_simple_bsd(cp, buf, X25GBITS(a->addrlens, called_addrlen), count);
	} else {
		count = X25GBITS(a->addrlens, called_addrlen);
		pk_simple_bsd(a->address_field, buf, 0, count);
	}
	if (xcp->xc_addr.x25_net && (xcp->xc_nodnic || xcp->xc_prepnd0)) {
		octet           dnicname[sizeof(long) * NBBY / 3 + 2];

		sprintf((char *) dnicname, "%d", xcp->xc_addr.x25_net);
		prune_dnic((char *) buf, sa->x25_addr, dnicname, xcp);
	} else
		bcopy((caddr_t) buf, (caddr_t) sa->x25_addr, count + 1);
}

static void
save_extra(m0, fp, so)
	struct mbuf    *m0;
	octet          *fp;
	struct socket  *so;
{
	register struct mbuf *m;
	struct cmsghdr  cmsghdr;
	/* XXX: christos:
	 * used to be m_copy(m, 0, ...)
	 * I think it is supposed to be m_copy(m0, 
	 */
	if ((m = m_copy(m0, 0, (int) M_COPYALL)) != NULL) {
		int             off = fp - mtod(m0, octet *);
		int             len = m->m_pkthdr.len - off + sizeof(cmsghdr);
		cmsghdr.cmsg_len = len;
		cmsghdr.cmsg_level = AF_CCITT;
		cmsghdr.cmsg_type = PK_FACILITIES;
		m_adj(m, off);
		M_PREPEND(m, sizeof(cmsghdr), M_DONTWAIT);
		if (m == 0)
			return;
		bcopy((caddr_t) & cmsghdr, mtod(m, caddr_t), sizeof(cmsghdr));
		MCHTYPE(m, MT_CONTROL);
		sbappendrecord(&so->so_rcv, m);
	}
}

/*
 * This routine handles incoming call packets. It matches the protocol field
 * on the Call User Data field (usually the first four bytes) with sockets
 * awaiting connections.
 */

void
pk_incoming_call(pkp, m0)
	struct pkcb    *pkp;
	struct mbuf    *m0;
{
	register struct pklcd *lcp = 0, *l;
	register struct sockaddr_x25 *sa;
	register struct x25_calladdr *a;
	register struct socket *so = 0;
	struct x25_packet *xp = mtod(m0, struct x25_packet *);
	struct mbuf    *m;
	struct x25config *xcp = pkp->pk_xcp;
	int             len = m0->m_pkthdr.len;
	unsigned        udlen;
	char           *errstr = "server unavailable";
	octet          *u, *facp;
	int             lcn = LCN(xp);

	/*
	 * First, copy the data from the incoming call packet to a X25
	 * address descriptor. It is to be regretted that you have to parse
	 * the facilities into a sockaddr to determine if reverse charging is
	 * being requested
	 */
	if ((m = m_get(M_DONTWAIT, MT_SONAME)) == 0)
		return;
	sa = mtod(m, struct sockaddr_x25 *);
	a = (struct x25_calladdr *) & xp->packet_data;
	facp = u = (octet *) (a->address_field +
			      ((X25GBITS(a->addrlens, called_addrlen) + X25GBITS(a->addrlens, calling_addrlen) + 1) / 2));
	u += *u + 1;
	udlen = min(16, ((octet *) xp) + len - u);
#if 0
	/* Cannot happen; udlen is unsigned */
	if (udlen < 0)
		udlen = 0;
#endif
	pk_from_bcd(a, 1, sa, pkp->pk_xcp);	/* get calling address */
	pk_parse_facilities(facp, sa);
	bcopy((caddr_t) u, sa->x25_udata, udlen);
	sa->x25_udlen = udlen;

	/*
	 * Now, loop through the listen sockets looking for a match on the
	 * PID. That is the first few octets of the user data field.
	 * This is the closest thing to a port number for X.25 packets.
	 * It does provide a way of multiplexing services at the user level.
	 */

	for (l = pk_listenhead.tqh_first; l; l = l->lcd_listen.tqe_next) {
		struct sockaddr_x25 *sxp = l->lcd_ceaddr;

		if (bcmp(sxp->x25_udata, u, sxp->x25_udlen))
			continue;
		if (sxp->x25_net &&
		    sxp->x25_net != xcp->xc_addr.x25_net)
			continue;
		/*
		 * don't accept incoming calls with the D-Bit on
		 * unless the server agrees
		 */
		if (X25GBITS(xp->bits, d_bit) && !(sxp->x25_opts.op_flags & X25_DBIT)) {
			errstr = "incoming D-Bit mismatch";
			break;
		}
		/*
		 * don't accept incoming collect calls unless
		 * the server sets the reverse charging option.
		 */
		if ((sxp->x25_opts.op_flags & (X25_OLDSOCKADDR | X25_REVERSE_CHARGE)) == 0 &&
		    sa->x25_opts.op_flags & X25_REVERSE_CHARGE) {
			errstr = "incoming collect call refused";
			break;
		}
		if (l->lcd_so) {
			so = sonewconn(l->lcd_so, SS_ISCONNECTED);
			if (so)
				lcp = (struct pklcd *) so->so_pcb;
		} else
			lcp = pk_attach((struct socket *) 0);
		if (lcp == 0) {
			/*
			 * Insufficient space or too many unaccepted
			 * connections.  Just throw the call away.
			 */
			errstr = "server malfunction";
			break;
		}
		lcp->lcd_upper = l->lcd_upper;
		lcp->lcd_upnext = l->lcd_upnext;
		lcp->lcd_lcn = lcn;
		lcp->lcd_state = RECEIVED_CALL;
		sa->x25_opts.op_flags |= (sxp->x25_opts.op_flags &
					~X25_REVERSE_CHARGE) | l->lcd_flags;
		pk_assoc(pkp, lcp, sa);
		lcp->lcd_faddr = *sa;
		lcp->lcd_laddr.x25_udlen = sxp->x25_udlen;
		lcp->lcd_craddr = &lcp->lcd_faddr;
		lcp->lcd_template = pk_template(lcp->lcd_lcn, X25_CALL_ACCEPTED);
		if (lcp->lcd_flags & X25_DBIT) {
			if (X25GBITS(xp->bits, d_bit))
				X25SBITS(mtod(lcp->lcd_template,
				      struct x25_packet *)->bits, d_bit, 1);
			else
				lcp->lcd_flags &= ~X25_DBIT;
		}
		if (so) {
			pk_output(lcp);
			soisconnected(so);
			if (so->so_options & SO_OOBINLINE)
				save_extra(m0, facp, so);
		} else if (lcp->lcd_upper) {
			(*lcp->lcd_upper) (m0, lcp);
		}
		(void) m_free(m);
		return;
	}

	/*
	 * If the call fails for whatever reason, we still need to build a
	 * skeleton LCD in order to be able to properly  receive the CLEAR
	 * CONFIRMATION.
	 */
#ifdef WATERLOO			/* be explicit */
	if (l == 0 && bcmp(sa->x25_udata, "ean", 3) == 0)
		pk_message(lcn, pkp->pk_xcp, "host=%s ean%c: %s",
			   sa->x25_addr, sa->x25_udata[3] & 0xff, errstr);
	else if (l == 0 && bcmp(sa->x25_udata, "\1\0\0\0", 4) == 0)
		pk_message(lcn, pkp->pk_xcp, "host=%s x29d: %s",
			   sa->x25_addr, errstr);
	else
#endif
		pk_message(lcn, pkp->pk_xcp, "host=%s pid=%x %x %x %x: %s",
			   sa->x25_addr, sa->x25_udata[0] & 0xff,
			   sa->x25_udata[1] & 0xff, sa->x25_udata[2] & 0xff,
			   sa->x25_udata[3] & 0xff, errstr);
	if ((lcp = pk_attach((struct socket *) 0)) == 0) {
		(void) m_free(m);
		return;
	}
	lcp->lcd_lcn = lcn;
	lcp->lcd_state = RECEIVED_CALL;
	pk_assoc(pkp, lcp, sa);
	(void) m_free(m);
	pk_clear(lcp, 0, 1);
}

void
pk_call_accepted(lcp, m)
	struct pklcd   *lcp;
	struct mbuf    *m;
{
	register struct x25_calladdr *ap;
	register octet *fcp;
	struct x25_packet *xp = mtod(m, struct x25_packet *);
	int             len = m->m_len;

	lcp->lcd_state = DATA_TRANSFER;
	if (lcp->lcd_so)
		soisconnected(lcp->lcd_so);
	if ((lcp->lcd_flags & X25_DBIT) && (X25GBITS(xp->bits, d_bit) == 0))
		lcp->lcd_flags &= ~X25_DBIT;
	if (len > 3) {
		ap = (struct x25_calladdr *) & xp->packet_data;
		fcp = (octet *) ap->address_field + (X25GBITS(ap->addrlens, calling_addrlen) +
			    X25GBITS(ap->addrlens, called_addrlen) + 1) / 2;
		if (fcp + *fcp <= ((octet *) xp) + len)
			pk_parse_facilities(fcp, lcp->lcd_ceaddr);
	}
	pk_assoc(lcp->lcd_pkp, lcp, lcp->lcd_ceaddr);
	if (lcp->lcd_so == 0 && lcp->lcd_upper)
		(*lcp->lcd_upper)(m, lcp);
}

void
pk_parse_facilities(fcp, sa)
	register octet *fcp;
	register struct sockaddr_x25 *sa;
{
	register octet *maxfcp;

	maxfcp = fcp + *fcp;
	fcp++;
	while (fcp < maxfcp) {
		/*
		 * Ignore national DCE or DTE facilities
		 */
		if (*fcp == 0 || *fcp == 0xff)
			break;
		switch (*fcp) {
		case FACILITIES_WINDOWSIZE:
			sa->x25_opts.op_wsize = fcp[1];
			fcp += 3;
			break;

		case FACILITIES_PACKETSIZE:
			sa->x25_opts.op_psize = fcp[1];
			fcp += 3;
			break;

		case FACILITIES_THROUGHPUT:
			sa->x25_opts.op_speed = fcp[1];
			fcp += 2;
			break;

		case FACILITIES_REVERSE_CHARGE:
			if (fcp[1] & 01)
				sa->x25_opts.op_flags |= X25_REVERSE_CHARGE;
			/*
			 * Datapac specific: for a X.25(1976) DTE, bit 2
			 * indicates a "hi priority" (eg. international) call.
			 */
			if (fcp[1] & 02 && sa->x25_opts.op_psize == 0)
				sa->x25_opts.op_psize = X25_PS128;
			fcp += 2;
			break;

		default:
#if 0
			 printf("unknown facility %x, class=%d\n", *fcp,
			     (*fcp & 0xc0) >> 6);
#endif
			switch ((*fcp & 0xc0) >> 6) {
			case 0:/* class A */
				fcp += 2;
				break;

			case 1:
				fcp += 3;
				break;

			case 2:
				fcp += 4;
				break;

			case 3:
				fcp++;
				fcp += *fcp;
			}
		}
	}
}