Check the return value of setuid, and make sure that it worked.

[mpls-ppp.git] / modules / ppp.c

/*
 * ppp.c - STREAMS multiplexing pseudo-device driver for PPP.
 *
 * Copyright (c) 1994 Paul Mackerras. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The name(s) of the authors of this software must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission.
 *
 * 4. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Paul Mackerras
 *     <paulus@samba.org>".
 *
 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * $Id: ppp.c,v 1.26 2002/12/06 09:49:15 paulus Exp $
 */

/*
 * This file is used under Solaris 2, SVR4, SunOS 4, and Digital UNIX.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/stream.h>
#include <sys/stropts.h>
#include <sys/errno.h>
#ifdef __osf__
#include <sys/ioctl.h>
#include <sys/cmn_err.h>
#define queclass(mp)    ((mp)->b_band & QPCTL)
#else
#include <sys/ioccom.h>
#endif
#include <sys/time.h>
#ifdef SVR4
#include <sys/cmn_err.h>
#include <sys/conf.h>
#include <sys/dlpi.h>
#include <sys/ddi.h>
#ifdef SOL2
#include <sys/ksynch.h>
#include <sys/kstat.h>
#include <sys/sunddi.h>
#include <sys/ethernet.h>
#else
#include <sys/socket.h>
#include <sys/sockio.h>
#include <net/if.h>
#include <netinet/in.h>
#endif /* SOL2 */
#else /* not SVR4 */
#include <sys/user.h>
#endif /* SVR4 */
#include <net/ppp_defs.h>
#include <net/pppio.h>
#include "ppp_mod.h"

/*
 * Modifications marked with #ifdef PRIOQ are for priority queueing of
 * interactive traffic, and are due to Marko Zec <zec@japa.tel.fer.hr>.
 */
#ifdef PRIOQ
#endif  /* PRIOQ */

#include <netinet/in.h> /* leave this outside of PRIOQ for htons */

#ifdef __STDC__
#define __P(x)  x
#else
#define __P(x)  ()
#endif

/*
 * The IP module may use this SAP value for IP packets.
 */
#ifndef ETHERTYPE_IP
#define ETHERTYPE_IP    0x800
#endif

#if !defined(ETHERTYPE_IPV6) 
#define ETHERTYPE_IPV6  0x86dd
#endif /* !defined(ETHERTYPE_IPV6) */

#if !defined(ETHERTYPE_ALLSAP) && defined(SOL2)
#define ETHERTYPE_ALLSAP   0
#endif /* !defined(ETHERTYPE_ALLSAP) && defined(SOL2) */

#if !defined(PPP_ALLSAP) && defined(SOL2)
#define PPP_ALLSAP  PPP_ALLSTATIONS
#endif /* !defined(PPP_ALLSAP) && defined(SOL2) */

extern time_t time;

#ifdef SOL2
/*
 * We use this reader-writer lock to ensure that the lower streams
 * stay connected to the upper streams while the lower-side put and
 * service procedures are running.  Essentially it is an existence
 * lock for the upper stream associated with each lower stream.
 */
krwlock_t ppp_lower_lock;
#define LOCK_LOWER_W    rw_enter(&ppp_lower_lock, RW_WRITER)
#define LOCK_LOWER_R    rw_enter(&ppp_lower_lock, RW_READER)
#define TRYLOCK_LOWER_R rw_tryenter(&ppp_lower_lock, RW_READER)
#define UNLOCK_LOWER    rw_exit(&ppp_lower_lock)

#define MT_ENTER(x)     mutex_enter(x)
#define MT_EXIT(x)      mutex_exit(x)

/*
 * Notes on multithreaded implementation for Solaris 2:
 *
 * We use an inner perimeter around each queue pair and an outer
 * perimeter around the whole driver.  The inner perimeter is
 * entered exclusively for all entry points (open, close, put,
 * service).  The outer perimeter is entered exclusively for open
 * and close and shared for put and service.  This is all done for
 * us by the streams framework.
 *
 * I used to think that the perimeters were entered for the lower
 * streams' put and service routines as well as for the upper streams'.
 * Because of problems experienced by people, and after reading the
 * documentation more closely, I now don't think that is true.  So we
 * now use ppp_lower_lock to give us an existence guarantee on the
 * upper stream controlling each lower stream.
 *
 * Shared entry to the outer perimeter protects the existence of all
 * the upper streams and their upperstr_t structures, and guarantees
 * that the following fields of any upperstr_t won't change:
 * nextmn, next, nextppa.  It guarantees that the lowerq field of an
 * upperstr_t won't go from non-zero to zero, that the global `ppas'
 * won't change and that the no lower stream will get unlinked.
 *
 * Shared (reader) access to ppa_lower_lock guarantees that no lower
 * stream will be unlinked and that the lowerq field of all upperstr_t
 * structures won't change.
 */

#else /* SOL2 */
#define LOCK_LOWER_W    0
#define LOCK_LOWER_R    0
#define TRYLOCK_LOWER_R 1
#define UNLOCK_LOWER    0
#define MT_ENTER(x)     0
#define MT_EXIT(x)      0

#endif /* SOL2 */

/*
 * Private information; one per upper stream.
 */
typedef struct upperstr {
    minor_t mn;                 /* minor device number */
    struct upperstr *nextmn;    /* next minor device */
    queue_t *q;                 /* read q associated with this upper stream */
    int flags;                  /* flag bits, see below */
    int state;                  /* current DLPI state */
    int sap;                    /* service access point */
    int req_sap;                /* which SAP the DLPI client requested */
    struct upperstr *ppa;       /* control stream for our ppa */
    struct upperstr *next;      /* next stream for this ppa */
    uint ioc_id;                /* last ioctl ID for this stream */
    enum NPmode npmode;         /* what to do with packets on this SAP */
    unsigned char rblocked;     /* flow control has blocked upper read strm */
        /* N.B. rblocked is only changed by control stream's put/srv procs */
    /*
     * There is exactly one control stream for each PPA.
     * The following fields are only used for control streams.
     */
    int ppa_id;
    queue_t *lowerq;            /* write queue attached below this PPA */
    struct upperstr *nextppa;   /* next control stream */
    int mru;
    int mtu;
    struct pppstat stats;       /* statistics */
    time_t last_sent;           /* time last NP packet sent */
    time_t last_recv;           /* time last NP packet rcvd */
#ifdef SOL2
    kmutex_t stats_lock;        /* lock for stats updates */
    kstat_t *kstats;            /* stats for netstat */
#endif /* SOL2 */
#ifdef LACHTCP
    int ifflags;
    char ifname[IFNAMSIZ];
    struct ifstats ifstats;
#endif /* LACHTCP */
} upperstr_t;

/* Values for flags */
#define US_PRIV         1       /* stream was opened by superuser */
#define US_CONTROL      2       /* stream is a control stream */
#define US_BLOCKED      4       /* flow ctrl has blocked lower write stream */
#define US_LASTMOD      8       /* no PPP modules below us */
#define US_DBGLOG       0x10    /* log various occurrences */
#define US_RBLOCKED     0x20    /* flow ctrl has blocked upper read stream */

#if defined(SOL2)
#if DL_CURRENT_VERSION >= 2
#define US_PROMISC      0x40    /* stream is promiscuous */
#endif /* DL_CURRENT_VERSION >= 2 */
#define US_RAWDATA      0x80    /* raw M_DATA, no DLPI header */
#endif /* defined(SOL2) */

#ifdef PRIOQ
static u_char max_band=0;
static u_char def_band=0;

#define IPPORT_DEFAULT          65535

/*
 * Port priority table
 * Highest priority ports are listed first, lowest are listed last.
 * ICMP & packets using unlisted ports will be treated as "default".
 * If IPPORT_DEFAULT is not listed here, "default" packets will be 
 * assigned lowest priority.
 * Each line should be terminated with "0".
 * Line containing only "0" marks the end of the list.
 */

static u_short prioq_table[]= {
    113, 53, 0,
    22, 23, 513, 517, 518, 0,
    514, 21, 79, 111, 0,
    25, 109, 110, 0,
    IPPORT_DEFAULT, 0,
    20, 70, 80, 8001, 8008, 8080, 0, /* 8001,8008,8080 - common proxy ports */
0 };

#endif  /* PRIOQ */


static upperstr_t *minor_devs = NULL;
static upperstr_t *ppas = NULL;

#ifdef SVR4
static int pppopen __P((queue_t *, dev_t *, int, int, cred_t *));
static int pppclose __P((queue_t *, int, cred_t *));
#else
static int pppopen __P((queue_t *, int, int, int));
static int pppclose __P((queue_t *, int));
#endif /* SVR4 */
static int pppurput __P((queue_t *, mblk_t *));
static int pppuwput __P((queue_t *, mblk_t *));
static int pppursrv __P((queue_t *));
static int pppuwsrv __P((queue_t *));
static int ppplrput __P((queue_t *, mblk_t *));
static int ppplwput __P((queue_t *, mblk_t *));
static int ppplrsrv __P((queue_t *));
static int ppplwsrv __P((queue_t *));
#ifndef NO_DLPI
static void dlpi_request __P((queue_t *, mblk_t *, upperstr_t *));
static void dlpi_error __P((queue_t *, upperstr_t *, int, int, int));
static void dlpi_ok __P((queue_t *, int));
#endif
static int send_data __P((mblk_t *, upperstr_t *));
static void new_ppa __P((queue_t *, mblk_t *));
static void attach_ppa __P((queue_t *, mblk_t *));
static void detach_ppa __P((queue_t *, mblk_t *));
static void detach_lower __P((queue_t *, mblk_t *));
static void debug_dump __P((queue_t *, mblk_t *));
static upperstr_t *find_dest __P((upperstr_t *, int));
#if defined(SOL2)
static upperstr_t *find_promisc __P((upperstr_t *, int));
static mblk_t *prepend_ether __P((upperstr_t *, mblk_t *, int));
static mblk_t *prepend_udind __P((upperstr_t *, mblk_t *, int));
static void promisc_sendup __P((upperstr_t *, mblk_t *, int, int));
#endif /* defined(SOL2) */
static int putctl2 __P((queue_t *, int, int, int));
static int putctl4 __P((queue_t *, int, int, int));
static int pass_packet __P((upperstr_t *ppa, mblk_t *mp, int outbound));
#ifdef FILTER_PACKETS
static int ip_hard_filter __P((upperstr_t *ppa, mblk_t *mp, int outbound));
#endif /* FILTER_PACKETS */

#define PPP_ID 0xb1a6
static struct module_info ppp_info = {
#ifdef PRIOQ
    PPP_ID, "ppp", 0, 512, 512, 384
#else
    PPP_ID, "ppp", 0, 512, 512, 128
#endif  /* PRIOQ */
};

static struct qinit pppurint = {
    pppurput, pppursrv, pppopen, pppclose, NULL, &ppp_info, NULL
};

static struct qinit pppuwint = {
    pppuwput, pppuwsrv, NULL, NULL, NULL, &ppp_info, NULL
};

static struct qinit ppplrint = {
    ppplrput, ppplrsrv, NULL, NULL, NULL, &ppp_info, NULL
};

static struct qinit ppplwint = {
    ppplwput, ppplwsrv, NULL, NULL, NULL, &ppp_info, NULL
};

#ifdef LACHTCP
extern struct ifstats *ifstats;
int pppdevflag = 0;
#endif

struct streamtab pppinfo = {
    &pppurint, &pppuwint,
    &ppplrint, &ppplwint
};

int ppp_count;

/*
 * How we maintain statistics.
 */
#ifdef SOL2
#define INCR_IPACKETS(ppa)                              \
        if (ppa->kstats != 0) {                         \
            KSTAT_NAMED_PTR(ppa->kstats)[0].value.ul++; \
        }
#define INCR_IERRORS(ppa)                               \
        if (ppa->kstats != 0) {                         \
            KSTAT_NAMED_PTR(ppa->kstats)[1].value.ul++; \
        }
#define INCR_OPACKETS(ppa)                              \
        if (ppa->kstats != 0) {                         \
            KSTAT_NAMED_PTR(ppa->kstats)[2].value.ul++; \
        }
#define INCR_OERRORS(ppa)                               \
        if (ppa->kstats != 0) {                         \
            KSTAT_NAMED_PTR(ppa->kstats)[3].value.ul++; \
        }
#endif

#ifdef LACHTCP
#define INCR_IPACKETS(ppa)      ppa->ifstats.ifs_ipackets++;
#define INCR_IERRORS(ppa)       ppa->ifstats.ifs_ierrors++;
#define INCR_OPACKETS(ppa)      ppa->ifstats.ifs_opackets++;
#define INCR_OERRORS(ppa)       ppa->ifstats.ifs_oerrors++;
#endif

/*
 * STREAMS driver entry points.
 */
static int
#ifdef SVR4
pppopen(q, devp, oflag, sflag, credp)
    queue_t *q;
    dev_t *devp;
    int oflag, sflag;
    cred_t *credp;
#else
pppopen(q, dev, oflag, sflag)
    queue_t *q;
    int dev;                    /* really dev_t */
    int oflag, sflag;
#endif
{
    upperstr_t *up;
    upperstr_t **prevp;
    minor_t mn;
#ifdef PRIOQ
    u_short *ptr;
    u_char new_band;
#endif  /* PRIOQ */

    if (q->q_ptr)
        DRV_OPEN_OK(dev);       /* device is already open */

#ifdef PRIOQ
    /* Calculate max_bband & def_band from definitions in prioq.h
       This colud be done at some more approtiate time (less often)
       but this way it works well so I'll just leave it here */

    max_band = 1;
    def_band = 0;
    ptr = prioq_table;
    while (*ptr) {
        new_band = 1;
        while (*ptr)
            if (*ptr++ == IPPORT_DEFAULT) {
                new_band = 0;
                def_band = max_band;
            }
        max_band += new_band;
        ptr++;
    }
    if (def_band)
        def_band = max_band - def_band;
    --max_band;
#endif  /* PRIOQ */

    if (sflag == CLONEOPEN) {
        mn = 0;
        for (prevp = &minor_devs; (up = *prevp) != 0; prevp = &up->nextmn) {
            if (up->mn != mn)
                break;
            ++mn;
        }
    } else {
#ifdef SVR4
        mn = getminor(*devp);
#else
        mn = minor(dev);
#endif
        for (prevp = &minor_devs; (up = *prevp) != 0; prevp = &up->nextmn) {
            if (up->mn >= mn)
                break;
        }
        if (up->mn == mn) {
            /* this can't happen */
            q->q_ptr = WR(q)->q_ptr = (caddr_t) up;
            DRV_OPEN_OK(dev);
        }
    }

    /*
     * Construct a new minor node.
     */
    up = (upperstr_t *) ALLOC_SLEEP(sizeof(upperstr_t));
    bzero((caddr_t) up, sizeof(upperstr_t));
    if (up == 0) {
        DPRINT("pppopen: out of kernel memory\n");
        OPEN_ERROR(ENXIO);
    }
    up->nextmn = *prevp;
    *prevp = up;
    up->mn = mn;
#ifdef SVR4
    *devp = makedevice(getmajor(*devp), mn);
#endif
    up->q = q;
    if (NOTSUSER() == 0)
        up->flags |= US_PRIV;
#ifndef NO_DLPI
    up->state = DL_UNATTACHED;
#endif
#ifdef LACHTCP
    up->ifflags = IFF_UP | IFF_POINTOPOINT;
#endif
    up->sap = -1;
    up->last_sent = up->last_recv = time;
    up->npmode = NPMODE_DROP;
    q->q_ptr = (caddr_t) up;
    WR(q)->q_ptr = (caddr_t) up;
    noenable(WR(q));
#ifdef SOL2
    mutex_init(&up->stats_lock, NULL, MUTEX_DRIVER, NULL);
#endif
    ++ppp_count;

    qprocson(q);
    DRV_OPEN_OK(makedev(major(dev), mn));
}

static int
#ifdef SVR4
pppclose(q, flag, credp)
    queue_t *q;
    int flag;
    cred_t *credp;
#else
pppclose(q, flag)
    queue_t *q;
    int flag;
#endif
{
    upperstr_t *up, **upp;
    upperstr_t *as, *asnext;
    upperstr_t **prevp;

    qprocsoff(q);

    up = (upperstr_t *) q->q_ptr;
    if (up == 0) {
        DPRINT("pppclose: q_ptr = 0\n");
        return 0;
    }
    if (up->flags & US_DBGLOG)
        DPRINT2("ppp/%d: close, flags=%x\n", up->mn, up->flags);
    if (up->flags & US_CONTROL) {
#ifdef LACHTCP
        struct ifstats *ifp, *pifp;
#endif
        if (up->lowerq != 0) {
            /* Gack! the lower stream should have be unlinked earlier! */
            DPRINT1("ppp%d: lower stream still connected on close?\n",
                    up->mn);
            LOCK_LOWER_W;
            up->lowerq->q_ptr = 0;
            RD(up->lowerq)->q_ptr = 0;
            up->lowerq = 0;
            UNLOCK_LOWER;
        }

        /*
         * This stream represents a PPA:
         * For all streams attached to the PPA, clear their
         * references to this PPA.
         * Then remove this PPA from the list of PPAs.
         */
        for (as = up->next; as != 0; as = asnext) {
            asnext = as->next;
            as->next = 0;
            as->ppa = 0;
            if (as->flags & US_BLOCKED) {
                as->flags &= ~US_BLOCKED;
                flushq(WR(as->q), FLUSHDATA);
            }
        }
        for (upp = &ppas; *upp != 0; upp = &(*upp)->nextppa)
            if (*upp == up) {
                *upp = up->nextppa;
                break;
            }
#ifdef LACHTCP
        /* Remove the statistics from the active list.  */
        for (ifp = ifstats, pifp = 0; ifp; ifp = ifp->ifs_next) {
            if (ifp == &up->ifstats) {
                if (pifp)
                    pifp->ifs_next = ifp->ifs_next;
                else
                    ifstats = ifp->ifs_next;
                break;
            }
            pifp = ifp;
        }
#endif
    } else {
        /*
         * If this stream is attached to a PPA,
         * remove it from the PPA's list.
         */
        if ((as = up->ppa) != 0) {
            for (; as->next != 0; as = as->next)
                if (as->next == up) {
                    as->next = up->next;
                    break;
                }
        }
    }

#ifdef SOL2
    if (up->kstats)
        kstat_delete(up->kstats);
    mutex_destroy(&up->stats_lock);
#endif

    q->q_ptr = NULL;
    WR(q)->q_ptr = NULL;

    for (prevp = &minor_devs; *prevp != 0; prevp = &(*prevp)->nextmn) {
        if (*prevp == up) {
            *prevp = up->nextmn;
            break;
        }
    }
    FREE(up, sizeof(upperstr_t));
    --ppp_count;

    return 0;
}

/*
 * A message from on high.  We do one of three things:
 *      - qreply()
 *      - put the message on the lower write stream
 *      - queue it for our service routine
 */
static int
pppuwput(q, mp)
    queue_t *q;
    mblk_t *mp;
{
    upperstr_t *us, *ppa, *nps;
    struct iocblk *iop;
    struct linkblk *lb;
#ifdef LACHTCP
    struct ifreq *ifr;
    int i;
#endif
    queue_t *lq;
    int error, n, sap;
    mblk_t *mq;
    struct ppp_idle *pip;
#ifdef PRIOQ
    queue_t *tlq;
#endif  /* PRIOQ */
#ifdef NO_DLPI
    upperstr_t *os;
#endif

    us = (upperstr_t *) q->q_ptr;
    if (us == 0) {
        DPRINT("pppuwput: q_ptr = 0!\n");
        return 0;
    }
    if (mp == 0) {
        DPRINT1("pppuwput/%d: mp = 0!\n", us->mn);
        return 0;
    }
    if (mp->b_datap == 0) {
        DPRINT1("pppuwput/%d: mp->b_datap = 0!\n", us->mn);
        return 0;
    }
    switch (mp->b_datap->db_type) {
#ifndef NO_DLPI
    case M_PCPROTO:
    case M_PROTO:
        dlpi_request(q, mp, us);
        break;
#endif /* NO_DLPI */

    case M_DATA:
        if (us->flags & US_DBGLOG)
            DPRINT3("ppp/%d: uwput M_DATA len=%d flags=%x\n",
                    us->mn, msgdsize(mp), us->flags);
        if (us->ppa == 0 || msgdsize(mp) > us->ppa->mtu + PPP_HDRLEN
#ifndef NO_DLPI
            || (us->flags & US_CONTROL) == 0
#endif /* NO_DLPI */
            ) {
            DPRINT1("pppuwput: junk data len=%d\n", msgdsize(mp));
            freemsg(mp);
            break;
        }
#ifdef NO_DLPI
        if ((us->flags & US_CONTROL) == 0 && !pass_packet(us, mp, 1))
            break;
#endif
        if (!send_data(mp, us))
            putq(q, mp);
        break;

    case M_IOCTL:
        iop = (struct iocblk *) mp->b_rptr;
        error = EINVAL;
        if (us->flags & US_DBGLOG)
            DPRINT3("ppp/%d: ioctl %x count=%d\n",
                    us->mn, iop->ioc_cmd, iop->ioc_count);
        switch (iop->ioc_cmd) {
#if defined(SOL2)
        case DLIOCRAW:      /* raw M_DATA mode */
            us->flags |= US_RAWDATA;
            error = 0;
            break;
#endif /* defined(SOL2) */
        case I_LINK:
            if ((us->flags & US_CONTROL) == 0 || us->lowerq != 0)
                break;
            if (mp->b_cont == 0) {
                DPRINT1("pppuwput/%d: ioctl I_LINK b_cont = 0!\n", us->mn);
                break;
            }
            lb = (struct linkblk *) mp->b_cont->b_rptr;
            lq = lb->l_qbot;
            if (lq == 0) {
                DPRINT1("pppuwput/%d: ioctl I_LINK l_qbot = 0!\n", us->mn);
                break;
            }
            LOCK_LOWER_W;
            us->lowerq = lq;
            lq->q_ptr = (caddr_t) q;
            RD(lq)->q_ptr = (caddr_t) us->q;
            UNLOCK_LOWER;
            iop->ioc_count = 0;
            error = 0;
            us->flags &= ~US_LASTMOD;
            /* Unblock upper streams which now feed this lower stream. */
            qenable(q);
            /* Send useful information down to the modules which
               are now linked below us. */
            putctl2(lq, M_CTL, PPPCTL_UNIT, us->ppa_id);
            putctl4(lq, M_CTL, PPPCTL_MRU, us->mru);
            putctl4(lq, M_CTL, PPPCTL_MTU, us->mtu);
#ifdef PRIOQ
            /* Lower tty driver's queue hiwat/lowat from default 4096/128
               to 256/128 since we don't want queueing of data on
               output to physical device */

            freezestr(lq);
            for (tlq = lq; tlq->q_next != NULL; tlq = tlq->q_next)
                ;
            strqset(tlq, QHIWAT, 0, 256);
            strqset(tlq, QLOWAT, 0, 128);
            unfreezestr(lq);
#endif  /* PRIOQ */
            break;

        case I_UNLINK:
            if (mp->b_cont == 0) {
                DPRINT1("pppuwput/%d: ioctl I_UNLINK b_cont = 0!\n", us->mn);
                break;
            }
            lb = (struct linkblk *) mp->b_cont->b_rptr;
#if DEBUG
            if (us->lowerq != lb->l_qbot) {
                DPRINT2("ppp unlink: lowerq=%x qbot=%x\n",
                        us->lowerq, lb->l_qbot);
                break;
            }
#endif
            iop->ioc_count = 0;
            qwriter(q, mp, detach_lower, PERIM_OUTER);
            error = -1;
            break;

        case PPPIO_NEWPPA:
            if (us->flags & US_CONTROL)
                break;
            if ((us->flags & US_PRIV) == 0) {
                error = EPERM;
                break;
            }
            /* Arrange to return an int */
            if ((mq = mp->b_cont) == 0
                || mq->b_datap->db_lim - mq->b_rptr < sizeof(int)) {
                mq = allocb(sizeof(int), BPRI_HI);
                if (mq == 0) {
                    error = ENOSR;
                    break;
                }
                if (mp->b_cont != 0)
                    freemsg(mp->b_cont);
                mp->b_cont = mq;
                mq->b_cont = 0;
            }
            iop->ioc_count = sizeof(int);
            mq->b_wptr = mq->b_rptr + sizeof(int);
            qwriter(q, mp, new_ppa, PERIM_OUTER);
            error = -1;
            break;

        case PPPIO_ATTACH:
            /* like dlpi_attach, for programs which can't write to
               the stream (like pppstats) */
            if (iop->ioc_count != sizeof(int) || us->ppa != 0)
                break;
            if (mp->b_cont == 0) {
                DPRINT1("pppuwput/%d: ioctl PPPIO_ATTACH b_cont = 0!\n", us->mn);
                break;
            }
            n = *(int *)mp->b_cont->b_rptr;
            for (ppa = ppas; ppa != 0; ppa = ppa->nextppa)
                if (ppa->ppa_id == n)
                    break;
            if (ppa == 0)
                break;
            us->ppa = ppa;
            iop->ioc_count = 0;
            qwriter(q, mp, attach_ppa, PERIM_OUTER);
            error = -1;
            break;

#ifdef NO_DLPI
        case PPPIO_BIND:
            /* Attach to a given SAP. */
            if (iop->ioc_count != sizeof(int) || us->ppa == 0)
                break;
            if (mp->b_cont == 0) {
                DPRINT1("pppuwput/%d: ioctl PPPIO_BIND b_cont = 0!\n", us->mn);
                break;
            }
            n = *(int *)mp->b_cont->b_rptr;
            /* n must be a valid PPP network protocol number. */
            if (n < 0x21 || n > 0x3fff || (n & 0x101) != 1)
                break;
            /* check that no other stream is bound to this sap already. */
            for (os = us->ppa; os != 0; os = os->next)
                if (os->sap == n)
                    break;
            if (os != 0)
                break;
            us->sap = n;
            iop->ioc_count = 0;
            error = 0;
            break;
#endif /* NO_DLPI */

        case PPPIO_MRU:
            if (iop->ioc_count != sizeof(int) || (us->flags & US_CONTROL) == 0)
                break;
            if (mp->b_cont == 0) {
                DPRINT1("pppuwput/%d: ioctl PPPIO_MRU b_cont = 0!\n", us->mn);
                break;
            }
            n = *(int *)mp->b_cont->b_rptr;
            if (n <= 0 || n > PPP_MAXMRU)
                break;
            if (n < PPP_MRU)
                n = PPP_MRU;
            us->mru = n;
            if (us->lowerq)
                putctl4(us->lowerq, M_CTL, PPPCTL_MRU, n);
            error = 0;
            iop->ioc_count = 0;
            break;

        case PPPIO_MTU:
            if (iop->ioc_count != sizeof(int) || (us->flags & US_CONTROL) == 0)
                break;
            if (mp->b_cont == 0) {
                DPRINT1("pppuwput/%d: ioctl PPPIO_MTU b_cont = 0!\n", us->mn);
                break;
            }
            n = *(int *)mp->b_cont->b_rptr;
            if (n <= 0 || n > PPP_MAXMTU)
                break;
            us->mtu = n;
#ifdef LACHTCP
            /* The MTU reported in netstat, not used as IP max packet size! */
            us->ifstats.ifs_mtu = n;
#endif
            if (us->lowerq)
                putctl4(us->lowerq, M_CTL, PPPCTL_MTU, n);
            error = 0;
            iop->ioc_count = 0;
            break;

        case PPPIO_LASTMOD:
            us->flags |= US_LASTMOD;
            error = 0;
            break;

        case PPPIO_DEBUG:
            if (iop->ioc_count != sizeof(int))
                break;
            if (mp->b_cont == 0) {
                DPRINT1("pppuwput/%d: ioctl PPPIO_DEBUG b_cont = 0!\n", us->mn);
                break;
            }
            n = *(int *)mp->b_cont->b_rptr;
            if (n == PPPDBG_DUMP + PPPDBG_DRIVER) {
                qwriter(q, NULL, debug_dump, PERIM_OUTER);
                iop->ioc_count = 0;
                error = -1;
            } else if (n == PPPDBG_LOG + PPPDBG_DRIVER) {
                DPRINT1("ppp/%d: debug log enabled\n", us->mn);
                us->flags |= US_DBGLOG;
                iop->ioc_count = 0;
                error = 0;
            } else {
                if (us->ppa == 0 || us->ppa->lowerq == 0)
                    break;
                putnext(us->ppa->lowerq, mp);
                error = -1;
            }
            break;

        case PPPIO_NPMODE:
            if (iop->ioc_count != 2 * sizeof(int))
                break;
            if ((us->flags & US_CONTROL) == 0)
                break;
            if (mp->b_cont == 0) {
                DPRINT1("pppuwput/%d: ioctl PPPIO_NPMODE b_cont = 0!\n", us->mn);
                break;
            }
            sap = ((int *)mp->b_cont->b_rptr)[0];
            for (nps = us->next; nps != 0; nps = nps->next) {
                if (us->flags & US_DBGLOG)
                    DPRINT2("us = 0x%x, us->next->sap = 0x%x\n", nps, nps->sap);
                if (nps->sap == sap)
                    break;
            }
            if (nps == 0) {
                if (us->flags & US_DBGLOG)
                    DPRINT2("ppp/%d: no stream for sap %x\n", us->mn, sap);
                break;
            }
            /* XXX possibly should use qwriter here */
            nps->npmode = (enum NPmode) ((int *)mp->b_cont->b_rptr)[1];
            if (nps->npmode != NPMODE_QUEUE && (nps->flags & US_BLOCKED) != 0)
                qenable(WR(nps->q));
            iop->ioc_count = 0;
            error = 0;
            break;

        case PPPIO_GIDLE:
            if ((ppa = us->ppa) == 0)
                break;
            mq = allocb(sizeof(struct ppp_idle), BPRI_HI);
            if (mq == 0) {
                error = ENOSR;
                break;
            }
            if (mp->b_cont != 0)
                freemsg(mp->b_cont);
            mp->b_cont = mq;
            mq->b_cont = 0;
            pip = (struct ppp_idle *) mq->b_wptr;
            pip->xmit_idle = time - ppa->last_sent;
            pip->recv_idle = time - ppa->last_recv;
            mq->b_wptr += sizeof(struct ppp_idle);
            iop->ioc_count = sizeof(struct ppp_idle);
            error = 0;
            break;

#ifdef LACHTCP
        case SIOCSIFNAME:
            /* Sent from IP down to us.  Attach the ifstats structure.  */
            if (iop->ioc_count != sizeof(struct ifreq) || us->ppa == 0)
                break;
            ifr = (struct ifreq *)mp->b_cont->b_rptr;
            /* Find the unit number in the interface name.  */
            for (i = 0; i < IFNAMSIZ; i++) {
                if (ifr->ifr_name[i] == 0 ||
                    (ifr->ifr_name[i] >= '0' &&
                     ifr->ifr_name[i] <= '9'))
                    break;
                else
                    us->ifname[i] = ifr->ifr_name[i];
            }
            us->ifname[i] = 0;

            /* Convert the unit number to binary.  */
            for (n = 0; i < IFNAMSIZ; i++) {
                if (ifr->ifr_name[i] == 0) {
                    break;
                }
                else {
                    n = n * 10 + ifr->ifr_name[i] - '0';
                }
            }

            /* Verify the ppa.  */
            if (us->ppa->ppa_id != n)
                break;
            ppa = us->ppa;

            /* Set up the netstat block.  */
            strncpy (ppa->ifname, us->ifname, IFNAMSIZ);

            ppa->ifstats.ifs_name = ppa->ifname;
            ppa->ifstats.ifs_unit = n;
            ppa->ifstats.ifs_active = us->state != DL_UNBOUND;
            ppa->ifstats.ifs_mtu = ppa->mtu;

            /* Link in statistics used by netstat.  */
            ppa->ifstats.ifs_next = ifstats;
            ifstats = &ppa->ifstats;

            iop->ioc_count = 0;
            error = 0;
            break;

        case SIOCGIFFLAGS:
            if (!(us->flags & US_CONTROL)) {
                if (us->ppa)
                    us = us->ppa;
                else
                    break;
            }
            ((struct iocblk_in *)iop)->ioc_ifflags = us->ifflags;
            error = 0;
            break;

        case SIOCSIFFLAGS:
            if (!(us->flags & US_CONTROL)) {
                if (us->ppa)
                    us = us->ppa;
                else
                    break;
            }
            us->ifflags = ((struct iocblk_in *)iop)->ioc_ifflags;
            error = 0;
            break;

        case SIOCSIFADDR:
            if (!(us->flags & US_CONTROL)) {
                if (us->ppa)
                    us = us->ppa;
                else
                    break;
            }
            us->ifflags |= IFF_RUNNING;
            ((struct iocblk_in *)iop)->ioc_ifflags |= IFF_RUNNING;
            error = 0;
            break;

        case SIOCSIFMTU:
            /*
             * Vanilla SVR4 systems don't handle SIOCSIFMTU, rather
             * they take the MTU from the DL_INFO_ACK we sent in response
             * to their DL_INFO_REQ.  Fortunately, they will update the
             * MTU if we send an unsolicited DL_INFO_ACK up.
             */
            if ((mq = allocb(sizeof(dl_info_req_t), BPRI_HI)) == 0)
                break;          /* should do bufcall */
            ((union DL_primitives *)mq->b_rptr)->dl_primitive = DL_INFO_REQ;
            mq->b_wptr = mq->b_rptr + sizeof(dl_info_req_t);
            dlpi_request(q, mq, us);
            error = 0;
            break;

        case SIOCGIFNETMASK:
        case SIOCSIFNETMASK:
        case SIOCGIFADDR:
        case SIOCGIFDSTADDR:
        case SIOCSIFDSTADDR:
        case SIOCGIFMETRIC:
            error = 0;
            break;
#endif /* LACHTCP */

        default:
            if (us->ppa == 0 || us->ppa->lowerq == 0)
                break;
            us->ioc_id = iop->ioc_id;
            error = -1;
            switch (iop->ioc_cmd) {
            case PPPIO_GETSTAT:
            case PPPIO_GETCSTAT:
                if (us->flags & US_LASTMOD) {
                    error = EINVAL;
                    break;
                }
                putnext(us->ppa->lowerq, mp);
                break;
            default:
                if (us->flags & US_PRIV)
                    putnext(us->ppa->lowerq, mp);
                else {
                    DPRINT1("ppp ioctl %x rejected\n", iop->ioc_cmd);
                    error = EPERM;
                }
                break;
            }
            break;
        }

        if (error > 0) {
            iop->ioc_error = error;
            mp->b_datap->db_type = M_IOCNAK;
            qreply(q, mp);
        } else if (error == 0) {
            mp->b_datap->db_type = M_IOCACK;
            qreply(q, mp);
        }
        break;

    case M_FLUSH:
        if (us->flags & US_DBGLOG)
            DPRINT2("ppp/%d: flush %x\n", us->mn, *mp->b_rptr);
        if (*mp->b_rptr & FLUSHW)
            flushq(q, FLUSHDATA);
        if (*mp->b_rptr & FLUSHR) {
            *mp->b_rptr &= ~FLUSHW;
            qreply(q, mp);
        } else
            freemsg(mp);
        break;

    default:
        freemsg(mp);
        break;
    }
    return 0;
}

#ifndef NO_DLPI
static void
dlpi_request(q, mp, us)
    queue_t *q;
    mblk_t *mp;
    upperstr_t *us;
{
    union DL_primitives *d = (union DL_primitives *) mp->b_rptr;
    int size = mp->b_wptr - mp->b_rptr;
    mblk_t *reply, *np;
    upperstr_t *ppa, *os;
    int sap, len;
    dl_info_ack_t *info;
    dl_bind_ack_t *ackp;
#if DL_CURRENT_VERSION >= 2
    dl_phys_addr_ack_t  *paddrack;
    static struct ether_addr eaddr = {0};
#endif

    if (us->flags & US_DBGLOG)
        DPRINT3("ppp/%d: dlpi prim %x len=%d\n", us->mn,
                d->dl_primitive, size);
    switch (d->dl_primitive) {
    case DL_INFO_REQ:
        if (size < sizeof(dl_info_req_t))
            goto badprim;
        if ((reply = allocb(sizeof(dl_info_ack_t), BPRI_HI)) == 0)
            break;              /* should do bufcall */
        reply->b_datap->db_type = M_PCPROTO;
        info = (dl_info_ack_t *) reply->b_wptr;
        reply->b_wptr += sizeof(dl_info_ack_t);
        bzero((caddr_t) info, sizeof(dl_info_ack_t));
        info->dl_primitive = DL_INFO_ACK;
        info->dl_max_sdu = us->ppa? us->ppa->mtu: PPP_MAXMTU;
        info->dl_min_sdu = 1;
        info->dl_addr_length = sizeof(uint);
        info->dl_mac_type = DL_ETHER;   /* a bigger lie */
        info->dl_current_state = us->state;
        info->dl_service_mode = DL_CLDLS;
        info->dl_provider_style = DL_STYLE2;
#if DL_CURRENT_VERSION >= 2
        info->dl_sap_length = sizeof(uint);
        info->dl_version = DL_CURRENT_VERSION;
#endif
        qreply(q, reply);
        break;

    case DL_ATTACH_REQ:
        if (size < sizeof(dl_attach_req_t))
            goto badprim;
        if (us->state != DL_UNATTACHED || us->ppa != 0) {
            dlpi_error(q, us, DL_ATTACH_REQ, DL_OUTSTATE, 0);
            break;
        }
        for (ppa = ppas; ppa != 0; ppa = ppa->nextppa)
            if (ppa->ppa_id == d->attach_req.dl_ppa)
                break;
        if (ppa == 0) {
            dlpi_error(q, us, DL_ATTACH_REQ, DL_BADPPA, 0);
            break;
        }
        us->ppa = ppa;
        qwriter(q, mp, attach_ppa, PERIM_OUTER);
        return;

    case DL_DETACH_REQ:
        if (size < sizeof(dl_detach_req_t))
            goto badprim;
        if (us->state != DL_UNBOUND || us->ppa == 0) {
            dlpi_error(q, us, DL_DETACH_REQ, DL_OUTSTATE, 0);
            break;
        }
        qwriter(q, mp, detach_ppa, PERIM_OUTER);
        return;

    case DL_BIND_REQ:
        if (size < sizeof(dl_bind_req_t))
            goto badprim;
        if (us->state != DL_UNBOUND || us->ppa == 0) {
            dlpi_error(q, us, DL_BIND_REQ, DL_OUTSTATE, 0);
            break;
        }
#if 0
        /* apparently this test fails (unnecessarily?) on some systems */
        if (d->bind_req.dl_service_mode != DL_CLDLS) {
            dlpi_error(q, us, DL_BIND_REQ, DL_UNSUPPORTED, 0);
            break;
        }
#endif

        /* saps must be valid PPP network protocol numbers,
           except that we accept ETHERTYPE_IP in place of PPP_IP. */
        sap = d->bind_req.dl_sap;
        us->req_sap = sap;

#if defined(SOL2)
        if (us->flags & US_DBGLOG)
            DPRINT2("DL_BIND_REQ: ip gives sap = 0x%x, us = 0x%x", sap, us);

        if (sap == ETHERTYPE_IP)            /* normal IFF_IPV4 */
            sap = PPP_IP;
        else if (sap == ETHERTYPE_IPV6)     /* when IFF_IPV6 is set */
            sap = PPP_IPV6;
        else if (sap == ETHERTYPE_ALLSAP)   /* snoop gives sap of 0 */
            sap = PPP_ALLSAP;
        else {
            DPRINT2("DL_BIND_REQ: unrecognized sap = 0x%x, us = 0x%x", sap, us);
            dlpi_error(q, us, DL_BIND_REQ, DL_BADADDR, 0);
            break;
        }
#else
        if (sap == ETHERTYPE_IP)
            sap = PPP_IP;
        if (sap < 0x21 || sap > 0x3fff || (sap & 0x101) != 1) {
            dlpi_error(q, us, DL_BIND_REQ, DL_BADADDR, 0);
            break;
        }
#endif /* defined(SOL2) */

        /* check that no other stream is bound to this sap already. */
        for (os = us->ppa; os != 0; os = os->next)
            if (os->sap == sap)
                break;
        if (os != 0) {
            dlpi_error(q, us, DL_BIND_REQ, DL_NOADDR, 0);
            break;
        }

        us->sap = sap;
        us->state = DL_IDLE;

        if ((reply = allocb(sizeof(dl_bind_ack_t) + sizeof(uint),
                            BPRI_HI)) == 0)
            break;              /* should do bufcall */
        ackp = (dl_bind_ack_t *) reply->b_wptr;
        reply->b_wptr += sizeof(dl_bind_ack_t) + sizeof(uint);
        reply->b_datap->db_type = M_PCPROTO;
        bzero((caddr_t) ackp, sizeof(dl_bind_ack_t));
        ackp->dl_primitive = DL_BIND_ACK;
        ackp->dl_sap = sap;
        ackp->dl_addr_length = sizeof(uint);
        ackp->dl_addr_offset = sizeof(dl_bind_ack_t);
        *(uint *)(ackp+1) = sap;
        qreply(q, reply);
        break;

    case DL_UNBIND_REQ:
        if (size < sizeof(dl_unbind_req_t))
            goto badprim;
        if (us->state != DL_IDLE) {
            dlpi_error(q, us, DL_UNBIND_REQ, DL_OUTSTATE, 0);
            break;
        }
        us->sap = -1;
        us->state = DL_UNBOUND;
#ifdef LACHTCP
        us->ppa->ifstats.ifs_active = 0;
#endif
        dlpi_ok(q, DL_UNBIND_REQ);
        break;

    case DL_UNITDATA_REQ:
        if (size < sizeof(dl_unitdata_req_t))
            goto badprim;
        if (us->state != DL_IDLE) {
            dlpi_error(q, us, DL_UNITDATA_REQ, DL_OUTSTATE, 0);
            break;
        }
        if ((ppa = us->ppa) == 0) {
            cmn_err(CE_CONT, "ppp: in state dl_idle but ppa == 0?\n");
            break;
        }
        len = mp->b_cont == 0? 0: msgdsize(mp->b_cont);
        if (len > ppa->mtu) {
            DPRINT2("dlpi data too large (%d > %d)\n", len, ppa->mtu);
            break;
        }

#if defined(SOL2)
        /*
         * Should there be any promiscuous stream(s), send the data
         * up for each promiscuous stream that we recognize.
         */
        if (mp->b_cont)
            promisc_sendup(ppa, mp->b_cont, us->sap, 0);
#endif /* defined(SOL2) */

        mp->b_band = 0;
#ifdef PRIOQ
        /* Extract s_port & d_port from IP-packet, the code is a bit
           dirty here, but so am I, too... */
        if (mp->b_datap->db_type == M_PROTO && us->sap == PPP_IP
            && mp->b_cont != 0) {
            u_char *bb, *tlh;
            int iphlen, len;
            u_short *ptr;
            u_char band_unset, cur_band, syn;
            u_short s_port, d_port;

            bb = mp->b_cont->b_rptr; /* bb points to IP-header*/
            len = mp->b_cont->b_wptr - mp->b_cont->b_rptr;
            syn = 0;
            s_port = IPPORT_DEFAULT;
            d_port = IPPORT_DEFAULT;
            if (len >= 20) {    /* 20 = minimum length of IP header */
                iphlen = (bb[0] & 0x0f) * 4;
                tlh = bb + iphlen;
                len -= iphlen;
                switch (bb[9]) {
                case IPPROTO_TCP:
                    if (len >= 20) {          /* min length of TCP header */
                        s_port = (tlh[0] << 8) + tlh[1];
                        d_port = (tlh[2] << 8) + tlh[3];
                        syn = tlh[13] & 0x02;
                    }
                    break;
                case IPPROTO_UDP:
                    if (len >= 8) {           /* min length of UDP header */
                        s_port = (tlh[0] << 8) + tlh[1];
                        d_port = (tlh[2] << 8) + tlh[3];
                    }
                    break;
                }
            }

            /*
             * Now calculate b_band for this packet from the
             * port-priority table.
             */
            ptr = prioq_table;
            cur_band = max_band;
            band_unset = 1;
            while (*ptr) {
                while (*ptr && band_unset)
                    if (s_port == *ptr || d_port == *ptr++) {
                        mp->b_band = cur_band;
                        band_unset = 0;
                        break;
                    }
                ptr++;
                cur_band--;
            }
            if (band_unset)
                mp->b_band = def_band;
            /* It may be usable to urge SYN packets a bit */
            if (syn)
                mp->b_band++;
        }
#endif  /* PRIOQ */
        /* this assumes PPP_HDRLEN <= sizeof(dl_unitdata_req_t) */
        if (mp->b_datap->db_ref > 1) {
            np = allocb(PPP_HDRLEN, BPRI_HI);
            if (np == 0)
                break;          /* gak! */
            np->b_cont = mp->b_cont;
            mp->b_cont = 0;
            freeb(mp);
            mp = np;
        } else
            mp->b_datap->db_type = M_DATA;
        /* XXX should use dl_dest_addr_offset/length here,
           but we would have to translate ETHERTYPE_IP -> PPP_IP */
        mp->b_wptr = mp->b_rptr + PPP_HDRLEN;
        mp->b_rptr[0] = PPP_ALLSTATIONS;
        mp->b_rptr[1] = PPP_UI;
        mp->b_rptr[2] = us->sap >> 8;
        mp->b_rptr[3] = us->sap;
        if (pass_packet(us, mp, 1)) {
            if (!send_data(mp, us))
                putq(q, mp);
        }
        return;

#if DL_CURRENT_VERSION >= 2
    case DL_PHYS_ADDR_REQ:
        if (size < sizeof(dl_phys_addr_req_t))
            goto badprim;

        /*
         * Don't check state because ifconfig sends this one down too
         */

        if ((reply = allocb(sizeof(dl_phys_addr_ack_t)+ETHERADDRL, 
                        BPRI_HI)) == 0)
            break;              /* should do bufcall */
        reply->b_datap->db_type = M_PCPROTO;
        paddrack = (dl_phys_addr_ack_t *) reply->b_wptr;
        reply->b_wptr += sizeof(dl_phys_addr_ack_t);
        bzero((caddr_t) paddrack, sizeof(dl_phys_addr_ack_t)+ETHERADDRL);
        paddrack->dl_primitive = DL_PHYS_ADDR_ACK;
        paddrack->dl_addr_length = ETHERADDRL;
        paddrack->dl_addr_offset = sizeof(dl_phys_addr_ack_t);
        bcopy(&eaddr, reply->b_wptr, ETHERADDRL);
        reply->b_wptr += ETHERADDRL;
        qreply(q, reply);
        break;

#if defined(SOL2)
    case DL_PROMISCON_REQ:
        if (size < sizeof(dl_promiscon_req_t))
            goto badprim;
        us->flags |= US_PROMISC;
        dlpi_ok(q, DL_PROMISCON_REQ);
        break;

    case DL_PROMISCOFF_REQ:
        if (size < sizeof(dl_promiscoff_req_t))
            goto badprim;
        us->flags &= ~US_PROMISC;
        dlpi_ok(q, DL_PROMISCOFF_REQ);
        break;
#else
    case DL_PROMISCON_REQ:          /* fall thru */
    case DL_PROMISCOFF_REQ:         /* fall thru */
#endif /* defined(SOL2) */
#endif /* DL_CURRENT_VERSION >= 2 */

#if DL_CURRENT_VERSION >= 2
    case DL_SET_PHYS_ADDR_REQ:
    case DL_SUBS_BIND_REQ:
    case DL_SUBS_UNBIND_REQ:
    case DL_ENABMULTI_REQ:
    case DL_DISABMULTI_REQ:
    case DL_XID_REQ:
    case DL_TEST_REQ:
    case DL_REPLY_UPDATE_REQ:
    case DL_REPLY_REQ:
    case DL_DATA_ACK_REQ:
#endif
    case DL_CONNECT_REQ:
    case DL_TOKEN_REQ:
        dlpi_error(q, us, d->dl_primitive, DL_NOTSUPPORTED, 0);
        break;

    case DL_CONNECT_RES:
    case DL_DISCONNECT_REQ:
    case DL_RESET_REQ:
    case DL_RESET_RES:
        dlpi_error(q, us, d->dl_primitive, DL_OUTSTATE, 0);
        break;

    case DL_UDQOS_REQ:
        dlpi_error(q, us, d->dl_primitive, DL_BADQOSTYPE, 0);
        break;

#if DL_CURRENT_VERSION >= 2
    case DL_TEST_RES:
    case DL_XID_RES:
        break;
#endif

    default:
        cmn_err(CE_CONT, "ppp: unknown dlpi prim 0x%x\n", d->dl_primitive);
        /* fall through */
    badprim:
        dlpi_error(q, us, d->dl_primitive, DL_BADPRIM, 0);
        break;
    }
    freemsg(mp);
}

static void
dlpi_error(q, us, prim, err, uerr)
    queue_t *q;
    upperstr_t *us;
    int prim, err, uerr;
{
    mblk_t *reply;
    dl_error_ack_t *errp;

    if (us->flags & US_DBGLOG)
        DPRINT3("ppp/%d: dlpi error, prim=%x, err=%x\n", us->mn, prim, err);
    reply = allocb(sizeof(dl_error_ack_t), BPRI_HI);
    if (reply == 0)
        return;                 /* XXX should do bufcall */
    reply->b_datap->db_type = M_PCPROTO;
    errp = (dl_error_ack_t *) reply->b_wptr;
    reply->b_wptr += sizeof(dl_error_ack_t);
    errp->dl_primitive = DL_ERROR_ACK;
    errp->dl_error_primitive = prim;
    errp->dl_errno = err;
    errp->dl_unix_errno = uerr;
    qreply(q, reply);
}

static void
dlpi_ok(q, prim)
    queue_t *q;
    int prim;
{
    mblk_t *reply;
    dl_ok_ack_t *okp;

    reply = allocb(sizeof(dl_ok_ack_t), BPRI_HI);
    if (reply == 0)
        return;                 /* XXX should do bufcall */
    reply->b_datap->db_type = M_PCPROTO;
    okp = (dl_ok_ack_t *) reply->b_wptr;
    reply->b_wptr += sizeof(dl_ok_ack_t);
    okp->dl_primitive = DL_OK_ACK;
    okp->dl_correct_primitive = prim;
    qreply(q, reply);
}
#endif /* NO_DLPI */

static int
pass_packet(us, mp, outbound)
    upperstr_t *us;
    mblk_t *mp;
    int outbound;
{
    int pass;
    upperstr_t *ppa;

    if ((ppa = us->ppa) == 0) {
        freemsg(mp);
        return 0;
    }

#ifdef FILTER_PACKETS
    pass = ip_hard_filter(us, mp, outbound);
#else
    /*
     * Here is where we might, in future, decide whether to pass
     * or drop the packet, and whether it counts as link activity.
     */
    pass = 1;
#endif /* FILTER_PACKETS */

    if (pass < 0) {
        /* pass only if link already up, and don't update time */
        if (ppa->lowerq == 0) {
            freemsg(mp);
            return 0;
        }
        pass = 1;
    } else if (pass) {
        if (outbound)
            ppa->last_sent = time;
        else
            ppa->last_recv = time;
    }

    return pass;
}

/*
 * We have some data to send down to the lower stream (or up the
 * control stream, if we don't have a lower stream attached).
 * Returns 1 if the message was dealt with, 0 if it wasn't able
 * to be sent on and should therefore be queued up.
 */
static int
send_data(mp, us)
    mblk_t *mp;
    upperstr_t *us;
{
    upperstr_t *ppa;

    if ((us->flags & US_BLOCKED) || us->npmode == NPMODE_QUEUE)
        return 0;
    ppa = us->ppa;
    if (ppa == 0 || us->npmode == NPMODE_DROP || us->npmode == NPMODE_ERROR) {
        if (us->flags & US_DBGLOG)
            DPRINT2("ppp/%d: dropping pkt (npmode=%d)\n", us->mn, us->npmode);
        freemsg(mp);
        return 1;
    }
    if (ppa->lowerq == 0) {
        /* try to send it up the control stream */
        if (bcanputnext(ppa->q, mp->b_band)) {
            /*
             * The message seems to get corrupted for some reason if
             * we just send the message up as it is, so we send a copy.
             */
            mblk_t *np = copymsg(mp);
            freemsg(mp);
            if (np != 0)
                putnext(ppa->q, np);
            return 1;
        }
    } else {
        if (bcanputnext(ppa->lowerq, mp->b_band)) {
            MT_ENTER(&ppa->stats_lock);
            ppa->stats.ppp_opackets++;
            ppa->stats.ppp_obytes += msgdsize(mp);
#ifdef INCR_OPACKETS
            INCR_OPACKETS(ppa);
#endif
            MT_EXIT(&ppa->stats_lock);
            /*
             * The lower queue is only ever detached while holding an
             * exclusive lock on the whole driver.  So we can be confident
             * that the lower queue is still there.
             */
            putnext(ppa->lowerq, mp);
            return 1;
        }
    }
    us->flags |= US_BLOCKED;
    return 0;
}

/*
 * Allocate a new PPA id and link this stream into the list of PPAs.
 * This procedure is called with an exclusive lock on all queues in
 * this driver.
 */
static void
new_ppa(q, mp)
    queue_t *q;
    mblk_t *mp;
{
    upperstr_t *us, *up, **usp;
    int ppa_id;

    us = (upperstr_t *) q->q_ptr;
    if (us == 0) {
        DPRINT("new_ppa: q_ptr = 0!\n");
        return;
    }

    usp = &ppas;
    ppa_id = 0;
    while ((up = *usp) != 0 && ppa_id == up->ppa_id) {
        ++ppa_id;
        usp = &up->nextppa;
    }
    us->ppa_id = ppa_id;
    us->ppa = us;
    us->next = 0;
    us->nextppa = *usp;
    *usp = us;
    us->flags |= US_CONTROL;
    us->npmode = NPMODE_PASS;

    us->mtu = PPP_MTU;
    us->mru = PPP_MRU;

#ifdef SOL2
    /*
     * Create a kstats record for our statistics, so netstat -i works.
     */
    if (us->kstats == 0) {
        char unit[32];

        sprintf(unit, "ppp%d", us->ppa->ppa_id);
        us->kstats = kstat_create("ppp", us->ppa->ppa_id, unit,
                                  "net", KSTAT_TYPE_NAMED, 4, 0);
        if (us->kstats != 0) {
            kstat_named_t *kn = KSTAT_NAMED_PTR(us->kstats);

            strcpy(kn[0].name, "ipackets");
            kn[0].data_type = KSTAT_DATA_ULONG;
            strcpy(kn[1].name, "ierrors");
            kn[1].data_type = KSTAT_DATA_ULONG;
            strcpy(kn[2].name, "opackets");
            kn[2].data_type = KSTAT_DATA_ULONG;
            strcpy(kn[3].name, "oerrors");
            kn[3].data_type = KSTAT_DATA_ULONG;
            kstat_install(us->kstats);
        }
    }
#endif /* SOL2 */

    *(int *)mp->b_cont->b_rptr = ppa_id;
    mp->b_datap->db_type = M_IOCACK;
    qreply(q, mp);
}

static void
attach_ppa(q, mp)
    queue_t *q;
    mblk_t *mp;
{
    upperstr_t *us, *t;

    us = (upperstr_t *) q->q_ptr;
    if (us == 0) {
        DPRINT("attach_ppa: q_ptr = 0!\n");
        return;
    }

#ifndef NO_DLPI
    us->state = DL_UNBOUND;
#endif
    for (t = us->ppa; t->next != 0; t = t->next)
        ;
    t->next = us;
    us->next = 0;
    if (mp->b_datap->db_type == M_IOCTL) {
        mp->b_datap->db_type = M_IOCACK;
        qreply(q, mp);
    } else {
#ifndef NO_DLPI
        dlpi_ok(q, DL_ATTACH_REQ);
#endif
    }
}

static void
detach_ppa(q, mp)
    queue_t *q;
    mblk_t *mp;
{
    upperstr_t *us, *t;

    us = (upperstr_t *) q->q_ptr;
    if (us == 0) {
        DPRINT("detach_ppa: q_ptr = 0!\n");
        return;
    }

    for (t = us->ppa; t->next != 0; t = t->next)
        if (t->next == us) {
            t->next = us->next;
            break;
        }
    us->next = 0;
    us->ppa = 0;
#ifndef NO_DLPI
    us->state = DL_UNATTACHED;
    dlpi_ok(q, DL_DETACH_REQ);
#endif
}

/*
 * We call this with qwriter in order to give the upper queue procedures
 * the guarantee that the lower queue is not going to go away while
 * they are executing.
 */
static void
detach_lower(q, mp)
    queue_t *q;
    mblk_t *mp;
{
    upperstr_t *us;

    us = (upperstr_t *) q->q_ptr;
    if (us == 0) {
        DPRINT("detach_lower: q_ptr = 0!\n");
        return;
    }

    LOCK_LOWER_W;
    us->lowerq->q_ptr = 0;
    RD(us->lowerq)->q_ptr = 0;
    us->lowerq = 0;
    UNLOCK_LOWER;

    /* Unblock streams which now feed back up the control stream. */
    qenable(us->q);

    mp->b_datap->db_type = M_IOCACK;
    qreply(q, mp);
}

static int
pppuwsrv(q)
    queue_t *q;
{
    upperstr_t *us, *as;
    mblk_t *mp;

    us = (upperstr_t *) q->q_ptr;
    if (us == 0) {
        DPRINT("pppuwsrv: q_ptr = 0!\n");
        return 0;
    }

    /*
     * If this is a control stream, then this service procedure
     * probably got enabled because of flow control in the lower
     * stream being enabled (or because of the lower stream going
     * away).  Therefore we enable the service procedure of all
     * attached upper streams.
     */
    if (us->flags & US_CONTROL) {
        for (as = us->next; as != 0; as = as->next)
            qenable(WR(as->q));
    }

    /* Try to send on any data queued here. */
    us->flags &= ~US_BLOCKED;
    while ((mp = getq(q)) != 0) {
        if (!send_data(mp, us)) {
            putbq(q, mp);
            break;
        }
    }

    return 0;
}

/* should never get called... */
static int
ppplwput(q, mp)
    queue_t *q;
    mblk_t *mp;
{
    putnext(q, mp);
    return 0;
}

static int
ppplwsrv(q)
    queue_t *q;
{
    queue_t *uq;

    /*
     * Flow control has back-enabled this stream:
     * enable the upper write service procedure for
     * the upper control stream for this lower stream.
     */
    LOCK_LOWER_R;
    uq = (queue_t *) q->q_ptr;
    if (uq != 0)
        qenable(uq);
    UNLOCK_LOWER;
    return 0;
}

/*
 * This should only get called for control streams.
 */
static int
pppurput(q, mp)
    queue_t *q;
    mblk_t *mp;
{
    upperstr_t *ppa, *us;
    int proto, len;
    struct iocblk *iop;

    ppa = (upperstr_t *) q->q_ptr;
    if (ppa == 0) {
        DPRINT("pppurput: q_ptr = 0!\n");
        return 0;
    }

    switch (mp->b_datap->db_type) {
    case M_CTL:
        MT_ENTER(&ppa->stats_lock);
        switch (*mp->b_rptr) {
        case PPPCTL_IERROR:
#ifdef INCR_IERRORS
            INCR_IERRORS(ppa);
#endif
            ppa->stats.ppp_ierrors++;
            break;
        case PPPCTL_OERROR:
#ifdef INCR_OERRORS
            INCR_OERRORS(ppa);
#endif
            ppa->stats.ppp_oerrors++;
            break;
        }
        MT_EXIT(&ppa->stats_lock);
        freemsg(mp);
        break;

    case M_IOCACK:
    case M_IOCNAK:
        /*
         * Attempt to match up the response with the stream
         * that the request came from.
         */
        iop = (struct iocblk *) mp->b_rptr;
        for (us = ppa; us != 0; us = us->next)
            if (us->ioc_id == iop->ioc_id)
                break;
        if (us == 0)
            freemsg(mp);
        else
            putnext(us->q, mp);
        break;

    case M_HANGUP:
        /*
         * The serial device has hung up.  We don't want to send
         * the M_HANGUP message up to pppd because that will stop
         * us from using the control stream any more.  Instead we
         * send a zero-length message as an end-of-file indication.
         */
        freemsg(mp);
        mp = allocb(1, BPRI_HI);
        if (mp == 0) {
            DPRINT1("ppp/%d: couldn't allocate eof message!\n", ppa->mn);
            break;
        }
        putnext(ppa->q, mp);
        break;

    default:
        if (mp->b_datap->db_type == M_DATA) {
            len = msgdsize(mp);
            if (mp->b_wptr - mp->b_rptr < PPP_HDRLEN) {
                PULLUP(mp, PPP_HDRLEN);
                if (mp == 0) {
                    DPRINT1("ppp_urput: msgpullup failed (len=%d)\n", len);
                    break;
                }
            }
            MT_ENTER(&ppa->stats_lock);
            ppa->stats.ppp_ipackets++;
            ppa->stats.ppp_ibytes += len;
#ifdef INCR_IPACKETS
            INCR_IPACKETS(ppa);
#endif
            MT_EXIT(&ppa->stats_lock);

            proto = PPP_PROTOCOL(mp->b_rptr);

#if defined(SOL2)
            /*
             * Should there be any promiscuous stream(s), send the data
             * up for each promiscuous stream that we recognize.
             */
            promisc_sendup(ppa, mp, proto, 1);
#endif /* defined(SOL2) */

            if (proto < 0x8000 && (us = find_dest(ppa, proto)) != 0) {
                /*
                 * A data packet for some network protocol.
                 * Queue it on the upper stream for that protocol.
                 * XXX could we just putnext it?  (would require thought)
                 * The rblocked flag is there to ensure that we keep
                 * messages in order for each network protocol.
                 */
                if (!pass_packet(us, mp, 0))
                    break;
                if (!us->rblocked && !canput(us->q))
                    us->rblocked = 1;
                if (!us->rblocked)
                    putq(us->q, mp);
                else
                    putq(q, mp);
                break;
            }
        }
        /*
         * A control frame, a frame for an unknown protocol,
         * or some other message type.
         * Send it up to pppd via the control stream.
         */
        if (queclass(mp) == QPCTL || canputnext(ppa->q))
            putnext(ppa->q, mp);
        else
            putq(q, mp);
        break;
    }

    return 0;
}

static int
pppursrv(q)
    queue_t *q;
{
    upperstr_t *us, *as;
    mblk_t *mp, *hdr;
#ifndef NO_DLPI
    dl_unitdata_ind_t *ud;
#endif
    int proto;

    us = (upperstr_t *) q->q_ptr;
    if (us == 0) {
        DPRINT("pppursrv: q_ptr = 0!\n");
        return 0;
    }

    if (us->flags & US_CONTROL) {
        /*
         * A control stream.
         * If there is no lower queue attached, run the write service
         * routines of other upper streams attached to this PPA.
         */
        if (us->lowerq == 0) {
            as = us;
            do {
                if (as->flags & US_BLOCKED)
                    qenable(WR(as->q));
                as = as->next;
            } while (as != 0);
        }

        /*
         * Messages get queued on this stream's read queue if they
         * can't be queued on the read queue of the attached stream
         * that they are destined for.  This is for flow control -
         * when this queue fills up, the lower read put procedure will
         * queue messages there and the flow control will propagate
         * down from there.
         */
        while ((mp = getq(q)) != 0) {
            proto = PPP_PROTOCOL(mp->b_rptr);
            if (proto < 0x8000 && (as = find_dest(us, proto)) != 0) {
                if (!canput(as->q))
                    break;
                putq(as->q, mp);
            } else {
                if (!canputnext(q))
                    break;
                putnext(q, mp);
            }
        }
        if (mp) {
            putbq(q, mp);
        } else {
            /* can now put stuff directly on network protocol streams again */
            for (as = us->next; as != 0; as = as->next)
                as->rblocked = 0;
        }

        /*
         * If this stream has a lower stream attached,
         * enable the read queue's service routine.
         * XXX we should really only do this if the queue length
         * has dropped below the low-water mark.
         */
        if (us->lowerq != 0)
            qenable(RD(us->lowerq));
                
    } else {
        /*
         * A network protocol stream.  Put a DLPI header on each
         * packet and send it on.
         * (Actually, it seems that the IP module will happily
         * accept M_DATA messages without the DL_UNITDATA_IND header.)
         */
        while ((mp = getq(q)) != 0) {
            if (!canputnext(q)) {
                putbq(q, mp);
                break;
            }
#ifndef NO_DLPI
            proto = PPP_PROTOCOL(mp->b_rptr);
            mp->b_rptr += PPP_HDRLEN;
            hdr = allocb(sizeof(dl_unitdata_ind_t) + 2 * sizeof(uint),
                         BPRI_MED);
            if (hdr == 0) {
                /* XXX should put it back and use bufcall */
                freemsg(mp);
                continue;
            }
            hdr->b_datap->db_type = M_PROTO;
            ud = (dl_unitdata_ind_t *) hdr->b_wptr;
            hdr->b_wptr += sizeof(dl_unitdata_ind_t) + 2 * sizeof(uint);
            hdr->b_cont = mp;
            ud->dl_primitive = DL_UNITDATA_IND;
            ud->dl_dest_addr_length = sizeof(uint);
            ud->dl_dest_addr_offset = sizeof(dl_unitdata_ind_t);
            ud->dl_src_addr_length = sizeof(uint);
            ud->dl_src_addr_offset = ud->dl_dest_addr_offset + sizeof(uint);
#if DL_CURRENT_VERSION >= 2
            ud->dl_group_address = 0;
#endif
            /* Send the DLPI client the data with the SAP they requested,
               (e.g. ETHERTYPE_IP) rather than the PPP protocol number
               (e.g. PPP_IP) */
            ((uint *)(ud + 1))[0] = us->req_sap;        /* dest SAP */
            ((uint *)(ud + 1))[1] = us->req_sap;        /* src SAP */
            putnext(q, hdr);
#else /* NO_DLPI */
            putnext(q, mp);
#endif /* NO_DLPI */
        }
        /*
         * Now that we have consumed some packets from this queue,
         * enable the control stream's read service routine so that we
         * can process any packets for us that might have got queued
         * there for flow control reasons.
         */
        if (us->ppa)
            qenable(us->ppa->q);
    }

    return 0;
}

static upperstr_t *
find_dest(ppa, proto)
    upperstr_t *ppa;
    int proto;
{
    upperstr_t *us;

    for (us = ppa->next; us != 0; us = us->next)
        if (proto == us->sap)
            break;
    return us;
}

#if defined (SOL2)
/*
 * Test upstream promiscuous conditions. As of now, only pass IPv4 and
 * Ipv6 packets upstream (let PPP packets be decoded elsewhere).
 */
static upperstr_t *
find_promisc(us, proto)
    upperstr_t *us;
    int proto;
{

    if ((proto != PPP_IP) && (proto != PPP_IPV6))
        return (upperstr_t *)0;

    for ( ; us; us = us->next) {
        if ((us->flags & US_PROMISC) && (us->state == DL_IDLE))
            return us;
    }

    return (upperstr_t *)0;
}

/*
 * Prepend an empty Ethernet header to msg for snoop, et al.
 */
static mblk_t *
prepend_ether(us, mp, proto)
    upperstr_t *us;
    mblk_t *mp;
    int proto;
{
    mblk_t *eh;
    int type;

    if ((eh = allocb(sizeof(struct ether_header), BPRI_HI)) == 0) {
        freemsg(mp);
        return (mblk_t *)0;
    }

    if (proto == PPP_IP)
        type = ETHERTYPE_IP;
    else if (proto == PPP_IPV6)
        type = ETHERTYPE_IPV6;
    else 
        type = proto;       /* What else? Let decoder decide */

    eh->b_wptr += sizeof(struct ether_header);
    bzero((caddr_t)eh->b_rptr, sizeof(struct ether_header));
    ((struct ether_header *)eh->b_rptr)->ether_type = htons((short)type);
    eh->b_cont = mp;
    return (eh);
}

/*
 * Prepend DL_UNITDATA_IND mblk to msg
 */
static mblk_t *
prepend_udind(us, mp, proto)
    upperstr_t *us;
    mblk_t *mp;
    int proto;
{
    dl_unitdata_ind_t *dlu;
    mblk_t *dh;
    size_t size;

    size = sizeof(dl_unitdata_ind_t);
    if ((dh = allocb(size, BPRI_MED)) == 0) {
        freemsg(mp);
        return (mblk_t *)0;
    }

    dh->b_datap->db_type = M_PROTO;
    dh->b_wptr = dh->b_datap->db_lim;
    dh->b_rptr = dh->b_wptr - size;

    dlu = (dl_unitdata_ind_t *)dh->b_rptr;
    dlu->dl_primitive = DL_UNITDATA_IND;
    dlu->dl_dest_addr_length = 0;
    dlu->dl_dest_addr_offset = sizeof(dl_unitdata_ind_t);
    dlu->dl_src_addr_length = 0;
    dlu->dl_src_addr_offset = sizeof(dl_unitdata_ind_t);
    dlu->dl_group_address = 0;

    dh->b_cont = mp;
    return (dh);
}

/*
 * For any recognized promiscuous streams, send data upstream
 */
static void
promisc_sendup(ppa, mp, proto, skip)
    upperstr_t *ppa;
    mblk_t *mp;
    int proto, skip;
{
    mblk_t *dup_mp, *dup_dup_mp;
    upperstr_t *prus, *nprus;

    if ((prus = find_promisc(ppa, proto)) != 0) {
        if (dup_mp = dupmsg(mp)) {

            if (skip)
                dup_mp->b_rptr += PPP_HDRLEN;

            for ( ; nprus = find_promisc(prus->next, proto); 
                    prus = nprus) {

                if (dup_dup_mp = dupmsg(dup_mp)) {
                    if (canputnext(prus->q)) {
                        if (prus->flags & US_RAWDATA) {
                            dup_dup_mp = prepend_ether(prus, dup_dup_mp, proto);
                            putnext(prus->q, dup_dup_mp);
                        } else {
                            dup_dup_mp = prepend_udind(prus, dup_dup_mp, proto);
                            putnext(prus->q, dup_dup_mp);
                        }
                    } else {
                        DPRINT("ppp_urput: data to promisc q dropped\n");
                        freemsg(dup_dup_mp);
                    }
                }
            }

            if (canputnext(prus->q)) {
                if (prus->flags & US_RAWDATA) {
                    dup_mp = prepend_ether(prus, dup_mp, proto);
                    putnext(prus->q, dup_mp);
                } else {
                    dup_mp = prepend_udind(prus, dup_mp, proto);
                    putnext(prus->q, dup_mp);
                }
            } else {
                DPRINT("ppp_urput: data to promisc q dropped\n");
                freemsg(dup_mp);
            }
        }
    }
}
#endif /* defined(SOL2) */

/*
 * We simply put the message on to the associated upper control stream
 * (either here or in ppplrsrv).  That way we enter the perimeters
 * before looking through the list of attached streams to decide which
 * stream it should go up.
 */
static int
ppplrput(q, mp)
    queue_t *q;
    mblk_t *mp;
{
    queue_t *uq;
    struct iocblk *iop;

    switch (mp->b_datap->db_type) {
    case M_IOCTL:
        iop = (struct iocblk *) mp->b_rptr;
        iop->ioc_error = EINVAL;
        mp->b_datap->db_type = M_IOCNAK;
        qreply(q, mp);
        return 0;
    case M_FLUSH:
        if (*mp->b_rptr & FLUSHR)
            flushq(q, FLUSHDATA);
        if (*mp->b_rptr & FLUSHW) {
            *mp->b_rptr &= ~FLUSHR;
            qreply(q, mp);
        } else
            freemsg(mp);
        return 0;
    }

    /*
     * If we can't get the lower lock straight away, queue this one
     * rather than blocking, to avoid the possibility of deadlock.
     */
    if (!TRYLOCK_LOWER_R) {
        putq(q, mp);
        return 0;
    }

    /*
     * Check that we're still connected to the driver.
     */
    uq = (queue_t *) q->q_ptr;
    if (uq == 0) {
        UNLOCK_LOWER;
        DPRINT1("ppplrput: q = %x, uq = 0??\n", q);
        freemsg(mp);
        return 0;
    }

    /*
     * Try to forward the message to the put routine for the upper
     * control stream for this lower stream.
     * If there are already messages queued here, queue this one so
     * they don't get out of order.
     */
    if (queclass(mp) == QPCTL || (qsize(q) == 0 && canput(uq)))
        put(uq, mp);
    else
        putq(q, mp);

    UNLOCK_LOWER;
    return 0;
}

static int
ppplrsrv(q)
    queue_t *q;
{
    mblk_t *mp;
    queue_t *uq;

    /*
     * Packets get queued here for flow control reasons
     * or if the lrput routine couldn't get the lower lock
     * without blocking.
     */
    LOCK_LOWER_R;
    uq = (queue_t *) q->q_ptr;
    if (uq == 0) {
        UNLOCK_LOWER;
        flushq(q, FLUSHALL);
        DPRINT1("ppplrsrv: q = %x, uq = 0??\n", q);
        return 0;
    }
    while ((mp = getq(q)) != 0) {
        if (queclass(mp) == QPCTL || canput(uq))
            put(uq, mp);
        else {
            putbq(q, mp);
            break;
        }
    }
    UNLOCK_LOWER;
    return 0;
}

static int
putctl2(q, type, code, val)
    queue_t *q;
    int type, code, val;
{
    mblk_t *mp;

    mp = allocb(2, BPRI_HI);
    if (mp == 0)
        return 0;
    mp->b_datap->db_type = type;
    mp->b_wptr[0] = code;
    mp->b_wptr[1] = val;
    mp->b_wptr += 2;
    putnext(q, mp);
    return 1;
}

static int
putctl4(q, type, code, val)
    queue_t *q;
    int type, code, val;
{
    mblk_t *mp;

    mp = allocb(4, BPRI_HI);
    if (mp == 0)
        return 0;
    mp->b_datap->db_type = type;
    mp->b_wptr[0] = code;
    ((short *)mp->b_wptr)[1] = val;
    mp->b_wptr += 4;
    putnext(q, mp);
    return 1;
}

static void
debug_dump(q, mp)
    queue_t *q;
    mblk_t *mp;
{
    upperstr_t *us;
    queue_t *uq, *lq;

    DPRINT("ppp upper streams:\n");
    for (us = minor_devs; us != 0; us = us->nextmn) {
        uq = us->q;
        DPRINT3(" %d: q=%x rlev=%d",
                us->mn, uq, (uq? qsize(uq): 0));
        DPRINT3(" wlev=%d flags=0x%b", (uq? qsize(WR(uq)): 0),
                us->flags, "\020\1priv\2control\3blocked\4last");
        DPRINT3(" state=%x sap=%x req_sap=%x", us->state, us->sap,
                us->req_sap);
        if (us->ppa == 0)
            DPRINT(" ppa=?\n");
        else
            DPRINT1(" ppa=%d\n", us->ppa->ppa_id);
        if (us->flags & US_CONTROL) {
            lq = us->lowerq;
            DPRINT3("    control for %d lq=%x rlev=%d",
                    us->ppa_id, lq, (lq? qsize(RD(lq)): 0));
            DPRINT3(" wlev=%d mru=%d mtu=%d\n",
                    (lq? qsize(lq): 0), us->mru, us->mtu);
        }
    }
    mp->b_datap->db_type = M_IOCACK;
    qreply(q, mp);
}

#ifdef FILTER_PACKETS
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <netinet/tcp.h>

#define MAX_IPHDR    128     /* max TCP/IP header size */


/* The following table contains a hard-coded list of protocol/port pairs.
 * Any matching packets are either discarded unconditionally, or, 
 * if ok_if_link_up is non-zero when a connection does not currently exist
 * (i.e., they go through if the connection is present, but never initiate
 * a dial-out).
 * This idea came from a post by dm@garage.uun.org (David Mazieres)
 */
static struct pktfilt_tab { 
        int proto; 
        u_short port; 
        u_short ok_if_link_up; 
} pktfilt_tab[] = {
        { IPPROTO_UDP,  520,    1 },    /* RIP, ok to pass if link is up */
        { IPPROTO_UDP,  123,    1 },    /* NTP, don't keep up the link for it */
        { -1,           0,      0 }     /* terminator entry has port == -1 */
};


static int
ip_hard_filter(us, mp, outbound)
    upperstr_t *us;
    mblk_t *mp;
    int outbound;
{
    struct ip *ip;
    struct pktfilt_tab *pft;
    mblk_t *temp_mp;
    int proto;
    int len, hlen;


    /* Note, the PPP header has already been pulled up in all cases */
    proto = PPP_PROTOCOL(mp->b_rptr);
    if (us->flags & US_DBGLOG)
        DPRINT3("ppp/%d: filter, proto=0x%x, out=%d\n", us->mn, proto, outbound);

    switch (proto)
    {
    case PPP_IP:
        if ((mp->b_wptr - mp->b_rptr) == PPP_HDRLEN && mp->b_cont != 0) {
            temp_mp = mp->b_cont;
            len = msgdsize(temp_mp);
            hlen = (len < MAX_IPHDR) ? len : MAX_IPHDR;
            PULLUP(temp_mp, hlen);
            if (temp_mp == 0) {
                DPRINT2("ppp/%d: filter, pullup next failed, len=%d\n", 
                        us->mn, hlen);
                mp->b_cont = 0;         /* PULLUP() freed the rest */
                freemsg(mp);
                return 0;
            }
            ip = (struct ip *)mp->b_cont->b_rptr;
        }
        else {
            len = msgdsize(mp);
            hlen = (len < (PPP_HDRLEN+MAX_IPHDR)) ? len : (PPP_HDRLEN+MAX_IPHDR);
            PULLUP(mp, hlen);
            if (mp == 0) {
                DPRINT2("ppp/%d: filter, pullup failed, len=%d\n", 
                        us->mn, hlen);
                return 0;
            }
            ip = (struct ip *)(mp->b_rptr + PPP_HDRLEN);
        }

        /* For IP traffic, certain packets (e.g., RIP) may be either
         *   1.  ignored - dropped completely
         *   2.  will not initiate a connection, but
         *       will be passed if a connection is currently up.
         */
        for (pft=pktfilt_tab; pft->proto != -1; pft++) {
            if (ip->ip_p == pft->proto) {
                switch(pft->proto) {
                case IPPROTO_UDP:
                    if (((struct udphdr *) &((int *)ip)[ip->ip_hl])->uh_dport
                                == htons(pft->port)) goto endfor;
                    break;
                case IPPROTO_TCP:
                    if (((struct tcphdr *) &((int *)ip)[ip->ip_hl])->th_dport
                                == htons(pft->port)) goto endfor;
                    break;
                }       
            }
        }
        endfor:
        if (pft->proto != -1) {
            if (us->flags & US_DBGLOG)
                DPRINT3("ppp/%d: found IP pkt, proto=0x%x (%d)\n", 
                                us->mn, pft->proto, pft->port);
            /* Discard if not connected, or if not pass_with_link_up */
            /* else, if link is up let go by, but don't update time */
            return pft->ok_if_link_up? -1: 0;
        }
        break;
    } /* end switch (proto) */

    return 1;
}
#endif /* FILTER_PACKETS */