if_ppp.c

unix and linux net driver

 */
void
pppintr()
{
    struct ppp_softc *sc;
    int i, s, s2;
    struct mbuf *m;

    sc = ppp_softc;
    s = splnet();
    for (i = 0; i < NPPP; ++i, ++sc) {
	if (!(sc->sc_flags & SC_TBUSY)
	    && (sc->sc_if.if_snd.ifq_head || sc->sc_fastq.ifq_head)) {
	    s2 = splimp();
	    sc->sc_flags |= SC_TBUSY;
	    splx(s2);
	    (*sc->sc_start)(sc);
	}
	for (;;) {
	    s2 = splimp();
	    IF_DEQUEUE(&sc->sc_rawq, m);
	    splx(s2);
	    if (m == NULL)
		break;
	    ppp_inproc(sc, m);
	}
    }
    splx(s);
}

#ifdef PPP_COMPRESS
/*
 * Handle a CCP packet.  `rcvd' is 1 if the packet was received,
 * 0 if it is about to be transmitted.
 */
static void
ppp_ccp(sc, m, rcvd)
    struct ppp_softc *sc;
    struct mbuf *m;
    int rcvd;
{
    u_char *dp, *ep;
    struct mbuf *mp;
    int slen, s;

    /*
     * Get a pointer to the data after the PPP header.
     */
    if (m->m_len <= PPP_HDRLEN) {
	mp = m->m_next;
	if (mp == NULL)
	    return;
	dp = (mp != NULL)? mtod(mp, u_char *): NULL;
    } else {
	mp = m;
	dp = mtod(mp, u_char *) + PPP_HDRLEN;
    }

    ep = mtod(mp, u_char *) + mp->m_len;
    if (dp + CCP_HDRLEN > ep)
	return;
    slen = CCP_LENGTH(dp);
    if (dp + slen > ep) {
	if (sc->sc_flags & SC_DEBUG)
	    printf("if_ppp/ccp: not enough data in mbuf (%x+%x > %x+%x)\n",
		   dp, slen, mtod(mp, u_char *), mp->m_len);
	return;
    }

    switch (CCP_CODE(dp)) {
    case CCP_CONFREQ:
    case CCP_TERMREQ:
    case CCP_TERMACK:
	/* CCP must be going down - disable compression */
	if (sc->sc_flags & SC_CCP_UP) {
	    s = splimp();
	    sc->sc_flags &= ~(SC_CCP_UP | SC_COMP_RUN | SC_DECOMP_RUN);
	    splx(s);
	}
	break;

    case CCP_CONFACK:
	if (sc->sc_flags & SC_CCP_OPEN && !(sc->sc_flags & SC_CCP_UP)
	    && slen >= CCP_HDRLEN + CCP_OPT_MINLEN
	    && slen >= CCP_OPT_LENGTH(dp + CCP_HDRLEN) + CCP_HDRLEN) {
	    if (!rcvd) {
		/* we're agreeing to send compressed packets. */
		if (sc->sc_xc_state != NULL
		    && (*sc->sc_xcomp->comp_init)
			(sc->sc_xc_state, dp + CCP_HDRLEN, slen - CCP_HDRLEN,
			 sc->sc_if.if_unit, 0, sc->sc_flags & SC_DEBUG)) {
		    s = splimp();
		    sc->sc_flags |= SC_COMP_RUN;
		    splx(s);
		}
	    } else {
		/* peer is agreeing to send compressed packets. */
		if (sc->sc_rc_state != NULL
		    && (*sc->sc_rcomp->decomp_init)
			(sc->sc_rc_state, dp + CCP_HDRLEN, slen - CCP_HDRLEN,
			 sc->sc_if.if_unit, 0, sc->sc_mru,
			 sc->sc_flags & SC_DEBUG)) {
		    s = splimp();
		    sc->sc_flags |= SC_DECOMP_RUN;
		    sc->sc_flags &= ~(SC_DC_ERROR | SC_DC_FERROR);
		    splx(s);
		}
	    }
	}
	break;

    case CCP_RESETACK:
	if (sc->sc_flags & SC_CCP_UP) {
	    if (!rcvd) {
		if (sc->sc_xc_state && (sc->sc_flags & SC_COMP_RUN))
		    (*sc->sc_xcomp->comp_reset)(sc->sc_xc_state);
	    } else {
		if (sc->sc_rc_state && (sc->sc_flags & SC_DECOMP_RUN)) {
		    (*sc->sc_rcomp->decomp_reset)(sc->sc_rc_state);
		    s = splimp();
		    sc->sc_flags &= ~SC_DC_ERROR;
		    splx(s);
		}
	    }
	}
	break;
    }
}

/*
 * CCP is down; free (de)compressor state if necessary.
 */
static void
ppp_ccp_closed(sc)
    struct ppp_softc *sc;
{
    if (sc->sc_xc_state) {
	(*sc->sc_xcomp->comp_free)(sc->sc_xc_state);
	sc->sc_xc_state = NULL;
    }
    if (sc->sc_rc_state) {
	(*sc->sc_rcomp->decomp_free)(sc->sc_rc_state);
	sc->sc_rc_state = NULL;
    }
}
#endif /* PPP_COMPRESS */

/*
 * PPP packet input routine.
 * The caller has checked and removed the FCS and has inserted
 * the address/control bytes and the protocol high byte if they
 * were omitted.
 */
void
ppppktin(sc, m, lost)
    struct ppp_softc *sc;
    struct mbuf *m;
    int lost;
{
    int s = splimp();

    m->m_context = lost;
    IF_ENQUEUE(&sc->sc_rawq, m);
    schednetisr(NETISR_PPP);
    splx(s);
}

/*
 * Process a received PPP packet, doing decompression as necessary.
 * Should be called at splnet.
 */
#define COMPTYPE(proto)	((proto) == PPP_VJC_COMP? TYPE_COMPRESSED_TCP: \
			 TYPE_UNCOMPRESSED_TCP)

static void
ppp_inproc(sc, m)
    struct ppp_softc *sc;
    struct mbuf *m;
{
    struct ifnet *ifp = &sc->sc_if;
    struct ifqueue *inq, *lock;
    int s, ilen, xlen, proto, rv;
    u_char *cp, adrs, ctrl;
    struct mbuf *mp, *dmp = NULL, *pc;
    u_char *iphdr;
    u_int hlen;

    sc->sc_stats.ppp_ipackets++;

    if (sc->sc_flags & SC_LOG_INPKT) {
	ilen = 0;
	for (mp = m; mp != NULL; mp = mp->m_next)
	    ilen += mp->m_len;
	printf("ppp%d: got %d bytes\n", ifp->if_unit, ilen);
	pppdumpm(m);
    }

    cp = mtod(m, u_char *);
    adrs = PPP_ADDRESS(cp);
    ctrl = PPP_CONTROL(cp);
    proto = PPP_PROTOCOL(cp);

    if (m->m_context) {
	s = splimp();
	sc->sc_flags |= SC_VJ_RESET;
	splx(s);
    }

#ifdef PPP_COMPRESS
    /*
     * Decompress this packet if necessary, update the receiver's
     * dictionary, or take appropriate action on a CCP packet.
     */
    if (proto == PPP_COMP && sc->sc_rc_state && (sc->sc_flags & SC_DECOMP_RUN)
	&& !(sc->sc_flags & SC_DC_ERROR) && !(sc->sc_flags & SC_DC_FERROR)) {
	/* decompress this packet */
	rv = (*sc->sc_rcomp->decompress)(sc->sc_rc_state, m, &dmp);
	if (rv == DECOMP_OK) {
	    m_freem(m);
	    if (dmp == NULL) {
		/* no error, but no decompressed packet produced */
		return;
	    }
	    m = dmp;
	    cp = mtod(m, u_char *);
	    proto = PPP_PROTOCOL(cp);

	} else {
	    /*
	     * An error has occurred in decompression.
	     * Pass the compressed packet up to pppd, which may take
	     * CCP down or issue a Reset-Req.
	     */
	    if (sc->sc_flags & SC_DEBUG)
		printf("ppp%d: decompress failed %d\n", ifp->if_unit, rv);
	    s = splimp();
	    sc->sc_flags |= SC_VJ_RESET;
	    if (rv == DECOMP_ERROR)
		sc->sc_flags |= SC_DC_ERROR;
	    else
		sc->sc_flags |= SC_DC_FERROR;
	    splx(s);
	}

    } else {
	if (sc->sc_rc_state && (sc->sc_flags & SC_DECOMP_RUN)) {
	    (*sc->sc_rcomp->incomp)(sc->sc_rc_state, m);
	}
	if (proto == PPP_CCP) {
	    ppp_ccp(sc, m, 1);
	}
    }
#endif

    ilen = 0;
    for (mp = m; mp != NULL; mp = mp->m_next)
	ilen += mp->m_len;

#ifdef VJC
    if (sc->sc_flags & SC_VJ_RESET) {
	/*
	 * If we've missed a packet, we must toss subsequent compressed
	 * packets which don't have an explicit connection ID.
	 */
	if (sc->sc_comp)
	    sl_uncompress_tcp(NULL, 0, TYPE_ERROR, sc->sc_comp);
	s = splimp();
	sc->sc_flags &= ~SC_VJ_RESET;
	splx(s);
    }

    /*
     * See if we have a VJ-compressed packet to uncompress.
     */
    if (proto == PPP_VJC_COMP) {
	if ((sc->sc_flags & SC_REJ_COMP_TCP) || sc->sc_comp == 0)
	    goto bad;

	xlen = sl_uncompress_tcp_core(cp + PPP_HDRLEN, m->m_len - PPP_HDRLEN,
				      ilen - PPP_HDRLEN, TYPE_COMPRESSED_TCP,
				      sc->sc_comp, &iphdr, &hlen);

	if (xlen <= 0) {
	    if (sc->sc_flags & SC_DEBUG)
		printf("ppp%d: VJ uncompress failed on type comp\n",
			ifp->if_unit);
	    goto bad;
	}

	/* Copy the PPP and IP headers into a new mbuf. */
	MGET(mp, M_DONTWAIT, MT_DATA);
	if (mp == NULL)
	    goto bad;
	mp->m_len = 0;
	mp->m_next = NULL;
	if (hlen + PPP_HDRLEN > MLEN) {
	    MCLGET(mp, pc);
	    if (M_TRAILINGSPACE(mp) < hlen + PPP_HDRLEN) {
		m_freem(mp);
		goto bad;	/* lose if big headers and no clusters */
	    }
	}
	cp = mtod(mp, u_char *);
	cp[0] = adrs;
	cp[1] = ctrl;
	cp[2] = 0;
	cp[3] = PPP_IP;
	proto = PPP_IP;
	bcopy(iphdr, cp + PPP_HDRLEN, hlen);
	mp->m_len = hlen + PPP_HDRLEN;

	/*
	 * Trim the PPP and VJ headers off the old mbuf
	 * and stick the new and old mbufs together.
	 */
	m->m_off += PPP_HDRLEN + xlen;
	m->m_len -= PPP_HDRLEN + xlen;
	if (m->m_len <= M_TRAILINGSPACE(mp)) {
	    bcopy(mtod(m, u_char *), mtod(mp, u_char *) + mp->m_len, m->m_len);
	    mp->m_len += m->m_len;
	    MFREE(m, mp->m_next);
	} else
	    mp->m_next = m;
	m = mp;
	ilen += hlen - xlen;

    } else if (proto == PPP_VJC_UNCOMP) {
	if ((sc->sc_flags & SC_REJ_COMP_TCP) || sc->sc_comp == 0)
	    goto bad;

	xlen = sl_uncompress_tcp_core(cp + PPP_HDRLEN, m->m_len - PPP_HDRLEN,
				      ilen - PPP_HDRLEN, TYPE_UNCOMPRESSED_TCP,
				      sc->sc_comp, &iphdr, &hlen);

	if (xlen < 0) {
	    if (sc->sc_flags & SC_DEBUG)
		printf("ppp%d: VJ uncompress failed on type uncomp\n",
			ifp->if_unit);
	    goto bad;
	}

	proto = PPP_IP;
	cp[3] = PPP_IP;
    }
#endif /* VJC */

    /*
     * If the packet will fit in an ordinary mbuf, don't waste a
     * whole cluster on it.
     */
    if (ilen <= MLEN && M_IS_CLUSTER(m)) {
	MGET(mp, M_DONTWAIT, MT_DATA);
	if (mp != NULL) {
	    m_copydata(m, mtod(mp, caddr_t), ilen);
	    m_freem(m);
	    m = mp;
	    m->m_len = ilen;
	}
    }

    /*
     * Record the time that we received this packet.
     */
    if ((proto & 0x8000) == 0) {
	sc->sc_last_recv = time.tv_sec;
    }

#if NBPFILTER > 0
    /* See if bpf wants to look at the packet. */
    if (sc->sc_bpf)
	bpf_mtap(sc->sc_bpf, m);
#endif

    rv = 0;
    switch (proto) {
#ifdef INET
    case PPP_IP:
	/*
	 * IP packet - take off the ppp header and pass it up to IP.
	 */
	if ((ifp->if_flags & IFF_UP) == 0
	    || sc->sc_npmode[NP_IP] != NPMODE_PASS) {
	    /* interface is down - drop the packet. */
	    m_freem(m);
	    return;
	}
	m->m_off += PPP_HDRLEN;
	m->m_len -= PPP_HDRLEN;
	schednetisr(NETISR_IP);
	inq = &ipintrq;
	break;
#endif

    default:
	/*
	 * Some other protocol - place on input queue for read().
	 */
	inq = &sc->sc_inq;
	rv = 1;
	break;
    }

    /*
     * Put the packet on the appropriate input queue.
     */
    s = splimp();
    lock = inq;
    smp_lock(&lock->lk_ifqueue, LK_RETRY);
    if (IF_QFULL(inq)) {
	IF_DROP(inq);
	smp_unlock(&lock->lk_ifqueue);
	splx(s);
	if (sc->sc_flags & SC_DEBUG)
	    printf("ppp%d: input queue full\n", ifp->if_unit);
	goto bad;
    }
    IF_ENQUEUEIF(inq, m, &sc->sc_if);
    smp_unlock(&lock->lk_ifqueue);
    splx(s);
    ifp->if_ipackets++;

    if (rv)
	(*sc->sc_ctlp)(sc);

    return;

 bad:
    m_freem(m);
    sc->sc_if.if_ierrors++;
    sc->sc_stats.ppp_ierrors++;
}

#define MAX_DUMP_BYTES	128

static void
pppdumpm(m0)
    struct mbuf *m0;
{
    char buf[3*MAX_DUMP_BYTES+4];
    char *bp = buf;
    struct mbuf *m;
    static char digits[] = "0123456789abcdef";

    for (m = m0; m; m = m->m_next) {
	int l = m->m_len;
	u_char *rptr = mtod(m, u_char *);

	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)
	*bp++ = '>';
    *bp = 0;
    printf("%s\n", buf);
}

#endif	/* NPPP > 0 */