* If we've missed a packet, we must toss subsequent compressed	     * packets which don't have an explicit connection ID.	     */	    sl_uncompress_tcp(NULL, 0, TYPE_ERROR, &sc->sc_comp);#endif	    if ((sc->sc_flags & (SC_FLUSH | SC_ESCAPED)) == 0){		if (sc->sc_flags & SC_DEBUG)		    printf("ppp%d: bad fcs %x\n", sc->sc_if.if_unit,			   sc->sc_fcs);		sc->sc_if.if_ierrors++;	    } else		sc->sc_flags &= ~(SC_FLUSH | SC_ESCAPED);	    return;	}	if (ilen < PPP_HDRLEN + PPP_FCSLEN) {	    if (ilen) {		if (sc->sc_flags & SC_DEBUG)		    printf("ppp%d: too short (%d)\n", sc->sc_if.if_unit, ilen);		sc->sc_if.if_ierrors++;	    }	    return;	}	/*	 * Remove FCS trailer.  Somewhat painful...	 */	ilen -= 2;	if (--sc->sc_mc->m_len == 0) {	    for (m = sc->sc_m; m->m_next != sc->sc_mc; m = m->m_next)		;	    sc->sc_mc = m;	}	sc->sc_mc->m_len--;	/* excise this mbuf chain */	m = sc->sc_m;	sc->sc_m = sc->sc_mc->m_next;	sc->sc_mc->m_next = NULL;	if (sc->sc_flags & SC_LOG_INPKT) {	    printf("ppp%d: got %d bytes\n", sc->sc_if.if_unit, ilen);	    pppdumpm(m, ilen);	}		ppppktin(sc, m); 		/* handover packet to upper layer */	pppgetm(sc);				return;    }    if (sc->sc_flags & SC_FLUSH) {	if (sc->sc_flags & SC_LOG_FLUSH)	    ppplogchar(sc, c);	return;    }    if (c < 0x20 && (sc->sc_rasyncmap & (1 << c)))	return;    if (sc->sc_flags & SC_ESCAPED) {	sc->sc_flags &= ~SC_ESCAPED;	c ^= PPP_TRANS;    } else if (c == PPP_ESCAPE) {	sc->sc_flags |= SC_ESCAPED;	return;    }    /*     * Initialize buffer on first octet received.     * First octet could be address or protocol (when compressing     * address/control).     * Second octet is control.     * Third octet is first or second (when compressing protocol)     * octet of protocol.     * Fourth octet is second octet of protocol.     */    if (sc->sc_ilen == 0) {	/* reset the first input mbuf */	if (sc->sc_m == NULL) {	    pppgetm(sc);	    if (sc->sc_m == NULL) {		if (sc->sc_flags & SC_DEBUG)		    printf("ppp%d: no input mbufs!\n", sc->sc_if.if_unit);		goto flush;	    }	}	m = sc->sc_m;	m->m_len = 0;	m->m_data = M_DATASTART(sc->sc_m);	if (M_DATASIZE(sc->sc_m) >= HDROFF + PPP_HDRLEN)	    m->m_data += HDROFF;	/* allow room for VJ decompression */	sc->sc_mc = m;	sc->sc_mp = mtod(m, char *);	sc->sc_fcs = PPP_INITFCS;	if (c != PPP_ALLSTATIONS) {	    if (sc->sc_flags & SC_REJ_COMP_AC) {		if (sc->sc_flags & SC_DEBUG)		    printf("ppp%d: garbage received: 0x%x (need 0xFF)\n",			   sc->sc_if.if_unit, c);		goto flush;	    }	    *sc->sc_mp++ = PPP_ALLSTATIONS;	    *sc->sc_mp++ = PPP_UI;	    sc->sc_ilen += 2;	    m->m_len += 2;	}    }    if (sc->sc_ilen == 1 && c != PPP_UI) {	if (sc->sc_flags & SC_DEBUG)	    printf("ppp%d: missing UI (0x3), got 0x%x\n",		   sc->sc_if.if_unit, c);	goto flush;    }    if (sc->sc_ilen == 2 && (c & 1) == 1) {	/* a compressed protocol */	*sc->sc_mp++ = 0;	sc->sc_ilen++;	sc->sc_mc->m_len++;    }    if (sc->sc_ilen == 3 && (c & 1) == 0) {	if (sc->sc_flags & SC_DEBUG)	    printf("ppp%d: bad protocol %x\n", sc->sc_if.if_unit,		   (sc->sc_mp[-1] << 8) + c);	goto flush;    }    /* packet beyond configured mru? */    if (++sc->sc_ilen > sc->sc_mru + PPP_HDRLEN + PPP_FCSLEN) {	if (sc->sc_flags & SC_DEBUG)	    printf("ppp%d: packet too big\n", sc->sc_if.if_unit);	goto flush;    }    /* is this mbuf full? */    m = sc->sc_mc;    if (M_TRAILINGSPACE(m) <= 0) {	if (m->m_next == NULL) {	    pppgetm(sc);	    if (m->m_next == NULL) {		if (sc->sc_flags & SC_DEBUG)		    printf("ppp%d: too few input mbufs!\n", sc->sc_if.if_unit);		goto flush;	    }	}	sc->sc_mc = m = m->m_next;	m->m_len = 0;	m->m_data = M_DATASTART(m);	sc->sc_mp = mtod(m, char *);    }    ++m->m_len;    *sc->sc_mp++ = c;    sc->sc_fcs = PPP_FCS(sc->sc_fcs, c);    return; flush:    if (!(sc->sc_flags & SC_FLUSH)) {	sc->sc_if.if_ierrors++;	sc->sc_flags |= SC_FLUSH;	if (sc->sc_flags & SC_LOG_FLUSH)	    ppplogchar(sc, c);    }}/* * Process an ioctl request to interface. */static intpppioctl(ifp, cmd, data)    register struct ifnet *ifp;    int cmd;    caddr_t data;{    register struct ppp_softc *sc = ppp_softc[ifp->if_unit];    register struct ifaddr *ifa = (struct ifaddr *)data;    register struct ifreq *ifr = (struct ifreq *)data;    register M2_NETDRVCNFG *pm2DrvCnfg = (M2_NETDRVCNFG *)data;    register M2_NETDRVCNTRS *pm2DrvCntr = (M2_NETDRVCNTRS *)data;    int s = splimp(), error = 0;    switch ((u_int) cmd) {    case SIOCGIFFLAGS:        *(short *)data = ifp->if_flags;         break;    case SIOCSIFFLAGS:	if ((ifp->if_flags & IFF_RUNNING) == 0)	    ifp->if_flags &= ~IFF_UP;	break;    case SIOCSIFADDR:	if (ifa->ifa_addr->sa_family != AF_INET)	    error = EAFNOSUPPORT;	break;    case SIOCSIFDSTADDR:	if (ifa->ifa_dstaddr->sa_family != AF_INET)	    error = EAFNOSUPPORT;	break;    case SIOCSIFMTU:	sc->sc_if.if_mtu = ifr->ifr_mtu;	break;    case SIOCGIFMTU:	ifr->ifr_mtu = sc->sc_if.if_mtu;	break;    case SIOCADDMULTI:    case SIOCDELMULTI:        if (ifr == 0) {            error = EAFNOSUPPORT;            break;        }        switch(ifr->ifr_addr.sa_family) {#ifdef INET        case AF_INET:            break;#endif        default:            error = EAFNOSUPPORT;            break;        }        break;    case SIOCGMIB2CNFG:        pm2DrvCnfg->ifType = M2_ifType_ppp;		/* ppp type */        pm2DrvCnfg->ifSpecific.idLength = 0;		/* use default */	break;    case SIOCGMIB2CNTRS:				/* fill in counters */	pm2DrvCntr->ifInOctets = sc->sc_bytesrcvd;        pm2DrvCntr->ifInNUcastPkts = 0;        pm2DrvCntr->ifInDiscards = 0;        pm2DrvCntr->ifInUnknownProtos = ppp_if[ppp_unit]->unknownProto;	pm2DrvCntr->ifOutOctets = sc->sc_bytessent;        pm2DrvCntr->ifOutNUcastPkts = 0;        pm2DrvCntr->ifOutDiscards = 0;	if ((pm2DrvCntr->ifSpeed = ppp_if[ppp_unit]->baud_rate) == 0)	    pm2DrvCntr->ifSpeed = 9600;			/* nominal default */	break;    default:	error = EINVAL;    }    splx(s);    return (error);}#define	MAX_DUMP_BYTES	128static voidpppdumpm(m0, pktlen)    struct mbuf *m0;    int pktlen;{    char buf [3*MAX_DUMP_BYTES+4];    char *bp = buf;    struct mbuf *m;    static char digits [] = "0123456789abcdef";    for (m = m0; m && pktlen; m = m->m_next) {	int l = m->m_len;	u_char *rptr = mtod(m, u_char *);        if (pktlen > 0) {            if (l > pktlen)                l = pktlen;	    pktlen -= l;	}        while (l--) {            if (bp > buf + sizeof(buf) - 4)                goto done;            *bp++ = digits[*rptr >> 4]; /* convert byte to ascii hex */            *bp++ = digits[*rptr++ & 0xf];        }        if (m->m_next) {            if (bp > buf + sizeof(buf) - 3)                goto done;            *bp++ = '|';        } else            *bp++ = ' ';    }done:    if (m && pktlen)        *bp++ = '>';    *bp = 0;    printf("%s\n", buf);}static voidppplogchar(sc, c)    struct ppp_softc *sc;    int c;{    if (c >= 0)        sc->sc_rawin[sc->sc_rawin_count++] = c;    if (sc->sc_rawin_count >= sizeof(sc->sc_rawin)        || (c < 0 && sc->sc_rawin_count > 0)) {        printf("ppp%d input: ", sc->sc_if.if_unit);        pppdumpb(sc->sc_rawin, sc->sc_rawin_count);        sc->sc_rawin_count = 0;    }}static voidpppdumpb(b, l)    u_char *b;    int l;{    char buf [3*MAX_DUMP_BYTES+4];    char *bp = buf;    static char digits[] = "0123456789abcdef";    while (l--) {	if (bp >= buf + sizeof (buf) - 3) {	    *bp++ = '>';	    break;	}	*bp++ = digits [*b >> 4]; /* convert byte to ascii hex */	*bp++ = digits [*b++ & 0xf];        *bp++ = ' ';    }    *bp = 0;    printf("%s\n", buf);}/*  * Flush write output on the interface.  */static voidppp_wrt_flush(sc)    register struct ppp_softc *sc;{    register struct mbuf *m;    register int len;    register u_char *start, *stop, *cp;    int n, ndone, done;    struct mbuf *m2;    int count, fd;    char ch;    fd = sc->sc_fd;    for (;;) {        /*         * See if we have an existing packet partly sent.         * If not, get a new packet and start sending it.         * We take packets on the priority queue ahead of those         * on the normal queue.         */        m = sc->sc_outm;        if (m == NULL) {	    /*	     * Get another packet to be sent	     */	    m = ppp_dequeue(sc);	    if (m == NULL)	        break;	    /*	     * The extra PPP_FLAG will start up a new packet, and thus	     * will flush any accumulated garbage.  We do this whenever	     * the line may have been idle for some time.	     */	    ioctl(fd, FIONWRITE, (int) &count);	    if (count == 0) {	        ++sc->sc_bytessent;	        ch = PPP_FLAG;	        (void) write(fd, &ch, 1);	    }	    /* Calculate the FCS for the first mbuf's worth. */	    sc->sc_outfcs = pppfcs(PPP_INITFCS, mtod(m, u_char *), m->m_len);        }        for (;;) {	    start = mtod(m, u_char *);	    len = m->m_len;	    stop = start + len;	    while (len > 0) {	        /*	         * Find out how many bytes in the string we can	         * handle without doing something special.	         */	        for (cp = start; cp < stop; cp++)		    if (ESCAPE_P(*cp))		        break;	        n = cp - start;	        if (n) {		    int cc, nleft;		    for (nleft = n; nleft > 0; nleft -= cc) {		        if ((cc =  write(fd, (char *)start, n)) <= 0)			    break;		        if (cc > nleft)			    cc = nleft;		    }		    ndone = n - nleft;		    len -= ndone;		    start += ndone;		    sc->sc_bytessent += ndone;		    if (ndone < n)		        break;  /* packet doesn't fit */	        }	        /*	         * If there are characters left in the mbuf,	         * the first one must be special..	         * Put it out in a different form.	         */	        if (len) {		    ch = PPP_ESCAPE;		    if (write(fd, &ch, 1) != 1)		        break;		    ch = *start ^ PPP_TRANS;		    if (write(fd, &ch, 1) != 1)		        break;		    sc->sc_bytessent += 2;		    start++;		    len--;	        }	    }	    /*	     * If we didn't empty this mbuf, remember where we're up to.	     * If we emptied the last mbuf, try to add the FCS and closing	     * flag, and if we can't, leave sc_outm pointing to m, but with	     * m->m_len == 0, to remind us to output the FCS and flag later.	     */	    done = len == 0;	    if (done && m->m_next == NULL) {	        u_char *p;	        int c;	        u_char endseq[8];    	        /*	         * We may have to escape the bytes in the FCS.	         */	        p = endseq;	        c = ~sc->sc_outfcs & 0xFF;	        if (ESCAPE_P(c)) {		    *p++ = PPP_ESCAPE;		    *p++ = c ^ PPP_TRANS;	        } else		    *p++ = c;	        c = (~sc->sc_outfcs >> 8) & 0xFF;	        if (ESCAPE_P(c)) {		    *p++ = PPP_ESCAPE;		    *p++ = c ^ PPP_TRANS;	        } else		    *p++ = c;	        *p++ = PPP_FLAG;	        /*	         * Try to output the FCS and flag.  If the bytes	         * don't all fit, back out.	         */	        write(fd, (char *)endseq, (int)p-(int)endseq);	    }	    if (!done) {	        m->m_data = (caddr_t)start; 	        m->m_len = len;	        sc->sc_outm = m;	        break;         /* can't do any more at the moment */	    }	    /* Finished with this mbuf; free it and move on. */	    m2 = m_free (m);	    if (m2 == NULL)	        break;	    m = m2;	    sc->sc_outfcs = pppfcs(sc->sc_outfcs, mtod(m, u_char *), m->m_len);        }        /* Finished a packet */        sc->sc_outm = NULL;        sc->sc_bytessent++;     /* account for closing flag */        sc->sc_if.if_opackets++;    }}#endif  /* NPPP > 0 */