ppp_tty.c

unix and linux net driver

		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.
	     */
	    if (CCOUNT(&tp->t_outq) == 0) {
		++sc->sc_stats.ppp_obytes;
		(void) putc(PPP_FLAG, &tp->t_outq);
	    }

	    /* Calculate the FCS for the first mbuf's worth. */
	    sc->sc_outfcs = pppfcs(PPP_INITFCS, mtod(m, u_char *), m->m_len);
	    sc->sc_if.if_lastchange = time;
	}

	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) {
		    /* NetBSD (0.9 or later), 4.3-Reno or similar. */
		    ndone = n - b_to_q(start, n, &tp->t_outq);
		    len -= ndone;
		    start += ndone;
		    sc->sc_stats.ppp_obytes += 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) {
		    s = spltty();
		    if (putc(PPP_ESCAPE, &tp->t_outq))
			break;
		    if (putc(*start ^ PPP_TRANS, &tp->t_outq)) {
			(void) unputc(&tp->t_outq);
			splx(s);
			break;
		    }
		    splx(s);
		    sc->sc_stats.ppp_obytes += 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, *q;
		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.
		 */
		s = spltty();
		for (q = endseq; q < p; ++q)
		    if (putc(*q, &tp->t_outq)) {
			done = 0;
			for (; q > endseq; --q)
			    unputc(&tp->t_outq);
			break;
		    }
		splx(s);
		if (done)
		    sc->sc_stats.ppp_obytes += q - endseq;
	    }

	    if (!done) {
		/* remember where we got to */
		m->m_data = start;
		m->m_len = len;
		break;
	    }

	    /* Finished with this mbuf; free it and move on. */
	    MFREE(m, m2);
	    m = m2;
	    if (m == NULL) {
		/* Finished a packet */
		break;
	    }
	    sc->sc_outfcs = pppfcs(sc->sc_outfcs, mtod(m, u_char *), m->m_len);
	}

	/*
	 * If m == NULL, we have finished a packet.
	 * If m != NULL, we've either done as much work this time
	 * as we need to, or else we've filled up the output queue.
	 */
	sc->sc_outm = m;
	if (m)
	    break;
    }

    /* Call pppstart to start output again if necessary. */
    s = spltty();
    pppstart(tp);

    /*
     * This timeout is needed for operation on a pseudo-tty,
     * because the pty code doesn't call pppstart after it has
     * drained the t_outq.
     */
    if (!idle && (sc->sc_flags & SC_TIMEOUT) == 0) {
	timeout(ppp_timeout, (void *) sc, 1);
	sc->sc_flags |= SC_TIMEOUT;
    }

    splx(s);
}

/*
 * This gets called when a received packet is placed on
 * the inq, at splsoftnet.
 */
static void
pppasyncctlp(sc)
    struct ppp_softc *sc;
{
    struct tty *tp;
    int s;

    /* Put a placeholder byte in canq for ttselect()/ttnread(). */
    s = spltty();
    tp = (struct tty *) sc->sc_devp;
    putc(0, &tp->t_canq);
    ttwakeup(tp);
    splx(s);
}

/*
 * Start output on async tty interface.  If the transmit queue
 * has drained sufficiently, arrange for pppasyncstart to be
 * called later at splsoftnet.
 * Called at spltty or higher.
 */
int
pppstart(tp)
    register struct tty *tp;
{
    register struct ppp_softc *sc = (struct ppp_softc *) tp->t_sc;

    /*
     * If there is stuff in the output queue, send it now.
     * We are being called in lieu of ttstart and must do what it would.
     */
    if (tp->t_oproc != NULL)
	(*tp->t_oproc)(tp);

    /*
     * If the transmit queue has drained and the tty has not hung up
     * or been disconnected from the ppp unit, then tell if_ppp.c that
     * we need more output.
     */
    if (CCOUNT(&tp->t_outq) < PPP_LOWAT
	&& !((tp->t_state & TS_CARR_ON) == 0 && (tp->t_cflag & CLOCAL) == 0)
	&& sc != NULL && tp == (struct tty *) sc->sc_devp) {
	ppp_restart(sc);
    }

    return 0;
}

/*
 * Timeout routine - try to start some more output.
 */
static void
ppp_timeout(x)
    void *x;
{
    struct ppp_softc *sc = (struct ppp_softc *) x;
    struct tty *tp = (struct tty *) sc->sc_devp;
    int s;

    s = spltty();
    sc->sc_flags &= ~SC_TIMEOUT;
    pppstart(tp);
    splx(s);
}

/*
 * Allocate enough mbuf to handle current MRU.
 */
static void
pppgetm(sc)
    register struct ppp_softc *sc;
{
    struct mbuf *m, **mp;
    int len;

    mp = &sc->sc_m;
    for (len = sc->sc_mru + PPP_HDRLEN + PPP_FCSLEN; len > 0; ){
	if ((m = *mp) == NULL) {
	    MGETHDR(m, M_DONTWAIT, MT_DATA);
	    if (m == NULL)
		break;
	    *mp = m;
	    MCLGET(m, M_DONTWAIT);
	}
	len -= M_DATASIZE(m);
	mp = &m->m_next;
    }
}

/*
 * tty interface receiver interrupt.
 */
static unsigned paritytab[8] = {
    0x96696996, 0x69969669, 0x69969669, 0x96696996,
    0x69969669, 0x96696996, 0x96696996, 0x69969669
};

int
pppinput(c, tp)
    int c;
    register struct tty *tp;
{
    register struct ppp_softc *sc;
    struct mbuf *m;
    int ilen, s;

    sc = (struct ppp_softc *) tp->t_sc;
    if (sc == NULL || tp != (struct tty *) sc->sc_devp)
	return 0;

    ++tk_nin;
    ++sc->sc_stats.ppp_ibytes;

    if (c & TTY_FE) {
	/* framing error or overrun on this char - abort packet */
	if (sc->sc_flags & SC_DEBUG)
	    printf("ppp%d: bad char %x\n", sc->sc_if.if_unit, c);
	goto flush;
    }

    c &= 0xff;

    /*
     * Handle software flow control of output.
     */
    if (tp->t_iflag & IXON) {
	if (c == tp->t_cc[VSTOP] && tp->t_cc[VSTOP] != _POSIX_VDISABLE) {
	    if ((tp->t_state & TS_TTSTOP) == 0) {
		tp->t_state |= TS_TTSTOP;
		(*cdevsw[major(tp->t_dev)].d_stop)(tp, 0);
	    }
	    return 0;
	}
	if (c == tp->t_cc[VSTART] && tp->t_cc[VSTART] != _POSIX_VDISABLE) {
	    tp->t_state &= ~TS_TTSTOP;
	    if (tp->t_oproc != NULL)
		(*tp->t_oproc)(tp);
	    return 0;
	}
    }

    s = spltty();
    if (c & 0x80)
	sc->sc_flags |= SC_RCV_B7_1;
    else
	sc->sc_flags |= SC_RCV_B7_0;
    if (paritytab[c >> 5] & (1 << (c & 0x1F)))
	sc->sc_flags |= SC_RCV_ODDP;
    else
	sc->sc_flags |= SC_RCV_EVNP;
    splx(s);

    if (sc->sc_flags & SC_LOG_RAWIN)
	ppplogchar(sc, c);

    if (c == PPP_FLAG) {
	ilen = sc->sc_ilen;
	sc->sc_ilen = 0;

	if (sc->sc_rawin_count > 0) 
	    ppplogchar(sc, -1);

	/*
	 * If SC_ESCAPED is set, then we've seen the packet
	 * abort sequence "}~".
	 */
	if (sc->sc_flags & (SC_FLUSH | SC_ESCAPED)
	    || (ilen > 0 && sc->sc_fcs != PPP_GOODFCS)) {
	    s = spltty();
	    sc->sc_flags |= SC_PKTLOST;	/* note the dropped packet */
	    if ((sc->sc_flags & (SC_FLUSH | SC_ESCAPED)) == 0){
		if (sc->sc_flags & SC_DEBUG)
		    printf("ppp%d: bad fcs %x, pkt len %d\n",
			   sc->sc_if.if_unit, sc->sc_fcs, ilen);
		sc->sc_if.if_ierrors++;
		sc->sc_stats.ppp_ierrors++;
	    } else
		sc->sc_flags &= ~(SC_FLUSH | SC_ESCAPED);
	    splx(s);
	    return 0;
	}

	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);
		s = spltty();
		sc->sc_if.if_ierrors++;
		sc->sc_stats.ppp_ierrors++;
		sc->sc_flags |= SC_PKTLOST;
		splx(s);
	    }
	    return 0;
	}

	/*
	 * 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;

	ppppktin(sc, m, sc->sc_flags & SC_PKTLOST);
	if (sc->sc_flags & SC_PKTLOST) {
	    s = spltty();
	    sc->sc_flags &= ~SC_PKTLOST;
	    splx(s);
	}

	pppgetm(sc);
	return 0;
    }

    if (sc->sc_flags & SC_FLUSH) {
	if (sc->sc_flags & SC_LOG_FLUSH)
	    ppplogchar(sc, c);
	return 0;
    }

    if (c < 0x20 && (sc->sc_rasyncmap & (1 << c)))
	return 0;

    s = spltty();
    if (sc->sc_flags & SC_ESCAPED) {
	sc->sc_flags &= ~SC_ESCAPED;
	c ^= PPP_TRANS;
    } else if (c == PPP_ESCAPE) {
	sc->sc_flags |= SC_ESCAPED;
	splx(s);
	return 0;
    }
    splx(s);

    /*
     * 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);
	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 0;

 flush:
    if (!(sc->sc_flags & SC_FLUSH)) {
	s = spltty();
	sc->sc_if.if_ierrors++;
	sc->sc_stats.ppp_ierrors++;
	sc->sc_flags |= SC_FLUSH;
	splx(s);
	if (sc->sc_flags & SC_LOG_FLUSH)
	    ppplogchar(sc, c);
    }
    return 0;
}

#define MAX_DUMP_BYTES	128

static void
ppplogchar(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 void
pppdumpb(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);
}

#endif	/* NPPP > 0 */