[apple/xnu.git] / bsd / netccitt / pk_subr.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * 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 <sys/malloc.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>

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 }
};


/* 
 *  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;
        int pk_output ();

        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 = (caddr_t) lcp;
                so -> so_error = error;
        }
        return (lcp);
}

/* 
 *  Disconnect X.25 protocol from socket.
 */

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.
 */

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);
        /* sofree (so); /* gak!!! you can't do that here */
}

/* 
 *  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.
 */

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 (lcp, 0);
                                }
                        }
        }

        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.
 */

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; ifp; ifp = ifp -> if_next)
                for (ifa = ifp -> if_addrlist; ifa; ifa = ifa -> ifa_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))

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.
 */
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.
 */
pk_protolisten (spi, spilen, callee)
int (*callee) ();
{
        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 (MT_SONAME, M_DONTWAIT)) {
                        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.
 */

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;
}

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;

        struct rtentry *npaidb_enter ();
        struct pkcb *pk_newlink ();

        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 (rt -> rt_gateway, rt_key (rt), rt, 0))
                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, 0, &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, (struct sockaddr *)0, 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)

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.
 */

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);
}

pk_build_facilities (m, sa, type)
register struct mbuf *m;
struct sockaddr_x25 *sa;
{
        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);
}

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.
 */

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". 
 */

pk_clear (lcp, diagnostic, abortive)
register struct pklcd *lcp;
{
        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.  
 */
pk_flowcontrol (lcp, inhibit, forced)
register struct pklcd *lcp;
{
        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-intializes
 *  virtual circuit.
 */

static
pk_reset (lcp, diagnostic)
register struct pklcd *lcp;
{
        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.
 */

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) 
                sbflush (&so -> so_snd);
        else 
                sbflush (&lcp -> lcd_sb);
}

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

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

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

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

        case 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.
 */

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 (RESET, lcp,
                                "p(r) flow control error", 2);
                        return (ERROR_PACKET);
                }
        }
        else {
                if (pr < lcp -> lcd_output_window && pr > lcp -> lcd_ssn) {
                        pk_procerror (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 && ((so -> so_snd.sb_flags & SB_WAIT) || 
                   (so -> so_snd.sb_flags & SB_NOTIFY)) ||
                   (so->so_snd.sb_sel.si_flags & SI_SBSEL))
                sowwakeup (so);

        return (PACKET_OK);
}

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

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

        if (X25GBITS(xp -> bits, fmt_identifier) != 1)
                return (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 (INVALID_PACKET);
#endif
        /* 
         *  Test for data packet first.
         */
        if (!(xp -> packet_type & DATA_PACKET_DESIGNATOR))
                return (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 (RR);
                case X25_RNR:
                        return (RNR);
                case X25_REJECT:
                        return (REJECT);
                }

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

        case X25_CALL_ACCEPTED: 
                type = CALL_ACCEPTED;
                break;

        case X25_CLEAR: 
                type = CLEAR;
                break;

        case X25_CLEAR_CONFIRM: 
                type = CLEAR_CONF;
                break;

        case X25_INTERRUPT: 
                type = INTERRUPT;
                break;

        case X25_INTERRUPT_CONFIRM: 
                type = INTERRUPT_CONF;
                break;

        case X25_RESET: 
                type = RESET;
                break;

        case X25_RESET_CONFIRM: 
                type = RESET_CONF;
                break;

        case X25_RESTART: 
                type = RESTART;
                break;

        case X25_RESTART_CONFIRM: 
                type = RESTART_CONF;
                break;

        case X25_DIAGNOSTIC:
                type = DIAG_TYPE;
                break;

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

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

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.
 */

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, "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.
 */

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 */
pk_message (lcn, xcp, fmt, a1, a2, a3, a4, a5, a6)
struct x25config *xcp;
char *fmt;
{

        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: ");

        printf (fmt, a1, a2, a3, a4, a5, a6);
        printf ("\n");
}

pk_fragment (lcp, m0, qbit, mbit, wait)
struct mbuf *m0;
register struct pklcd *lcp;
{
        register struct mbuf *m = m0;
        register struct x25_packet *xp;
        register struct sockbuf *sb;
        struct mbuf *head = 0, *next, **mp = &head, *m_split ();
        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);
        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;
}