if_ppp.c

unix and linux net driver

    struct ppp_softc *sc;
{
    int s;
    NETBUF_T m;
    u_char *cp;
    int address, control, protocol;
#if NS_TARGET >= 40
    struct timeval tv_time;
#endif

    /*
     * Grab a packet to send: first try the fast queue, then the
     * normal queue.
     */
    m = nbq_dequeue(&sc->sc_fastq);
    if (m == NULL)
	m = nbq_dequeue(&sc->sc_slowq);
    if (m == NULL)
	return;

    /*
     * Extract the ppp header of the new packet.
     * The ppp header will be in one netbuf.
     */
    cp = mtod(m, u_char *);
    address = PPP_ADDRESS(cp);
    control = PPP_CONTROL(cp);
    protocol = PPP_PROTOCOL(cp);

#if NS_TARGET >= 40
	ns_time_to_timeval(clock_value(System), &tv_time);
#endif /* NS_TARGET */

    switch (protocol) {
    case PPP_IP:
	/*
	 * Update the time we sent the most recent packet.
	 */
#if NS_TARGET >= 40
	sc->sc_last_sent = tv_time.tv_sec;
#else
        sc->sc_last_sent = time.tv_sec;
#endif /* NS_TARGET */

#ifdef VJC
	/*
	 * If the packet is a TCP/IP packet, see if we can compress it.
	 */
	if (sc->sc_flags & SC_COMP_TCP) {
	    struct ip *ip;
	    int type;
	    u_char *vjhdr;

	    ip = (struct ip *) (cp + PPP_HDRLEN);
	    /* this code assumes the IP/TCP header is in one netbuf */
	    if (ip->ip_p == IPPROTO_TCP) {
		type = vj_compress_tcp(ip, NB_SIZE(m) - PPP_HDRLEN,
				       &sc->sc_comp,
				       !(sc->sc_flags & SC_NO_TCP_CCID), &vjhdr);
		switch (type) {
		case TYPE_UNCOMPRESSED_TCP:
		    protocol = PPP_VJC_UNCOMP;
		    break;
		case TYPE_COMPRESSED_TCP:
		    NB_SHRINK_TOP(m, vjhdr - (u_char *) ip);
		    protocol = PPP_VJC_COMP;
		    cp = mtod(m, u_char *);
		    cp[0] = address;	/* header has moved */
		    cp[1] = control;
		    cp[2] = 0;
		    break;
		}
		cp[3] = protocol;	/* update protocol in PPP header */
	    }
	}

#endif	/* VJC */

	break;

#ifdef PPP_COMPRESS
    case PPP_CCP:
	ppp_ccp(sc, m, 0);
	break;
#endif	/* PPP_COMPRESS */
    }


#ifdef PPP_COMPRESS
    if (protocol != PPP_LCP && protocol != PPP_CCP
	&& sc->sc_xc_state && (sc->sc_flags & SC_COMP_RUN)) {
	NETBUF_T mcomp;
	int slen, clen;

	slen = NB_SIZE(m);

	clen = (*sc->sc_xcomp->compress)
	    (sc->sc_xc_state, &mcomp, m, slen,
	     sc->sc_flags & SC_CCP_UP? if_mtu(sc->sc_if): 0);


	if (mcomp && (NB_SIZE(mcomp) >= slen))
	    IOLog("BSD Warning... packet growth: Orig=%d New=%d.\n",
		  slen, NB_SIZE(mcomp));

	if (mcomp != NULL) {

	    NB_FREE(m);
	    m = mcomp;
	    cp = mtod(m, u_char *);
	    protocol = cp[3];
	}
    }
#endif	/* PPP_COMPRESS */

    /*
     * Compress the address/control and protocol, if possible.
     */
    if (sc->sc_flags & SC_COMP_AC && address == PPP_ALLSTATIONS &&
	control == PPP_UI && protocol != PPP_ALLSTATIONS &&
	protocol != PPP_LCP) {
	/* can compress address/control */
	NB_SHRINK_TOP(m, 2);
    }
    if (sc->sc_flags & SC_COMP_PROT && protocol < 0xFF) {
	/* can compress protocol */
	if (mtod(m, u_char *) == cp) {
	    cp[2] = cp[1];	/* move address/control up */
	    cp[1] = cp[0];
	}
	NB_SHRINK_TOP(m, 1);
    }


    s = splimp();
    nbq_enqueue(&sc->sc_compq, m);
    (*sc->sc_start)(sc);
    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;
    NETBUF_T m;
    int rcvd;
{
    u_char *dp, *ep;
    int slen, s;

    /*
     * Get a pointer to the data after the PPP header.
     */
    dp = mtod(m, u_char *) + PPP_HDRLEN;

    ep = mtod(m, u_char *) + NB_SIZE(m);
    if (dp + CCP_HDRLEN > ep)
	return;
    slen = CCP_LENGTH(dp);
    if (dp + slen > ep) {
	IOLogDbg("ppp%d: ccp: not enough data in netbuf (%x+%x > %x+%x)\n",
		 if_unit(sc->sc_if), dp, slen, mtod(m, u_char *), NB_SIZE(m));
	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,
			 if_unit(sc->sc_if), 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,
			 if_unit(sc->sc_if),
#ifdef VJC
			 VJ_HDRLEN +
#endif
			 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);
		    nbq_flush(&sc->sc_compq);  /* Flush pre-compressed packets */
		  }
	    } 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;
    NETBUF_T m;
    int lost;
{
  int error, s = splimp();
  
  NB_SET_MARK(m,(lost ? M_ERRMARK : 0));
  
  /* XXX - we should check for the raw queue overflowing... */
  nbq_enqueue(&sc->sc_rawq, m);
  if (!sc->sc_decompsched)
    {
      if ((error = pppsched(pppintr_decomp, sc)) == KERN_SUCCESS)
	sc->sc_decompsched = 1;
      else
	IOLogDbg("ppp%d: decompression callout failed returning %d\n",
		 if_unit(sc->sc_if), error);
    }
  
  splx(s);
}

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

static void
ppp_inproc(sc, m)
    struct ppp_softc *sc;
    NETBUF_T m;
{
    struct nb_queue *inq;
    int s, ilen, xlen, proto, rv;
    mark_t flags;
    u_char *cp, adrs, ctrl;
    NETBUF_T dmp;
    u_char *iphdr;
    u_int hlen;
#if NS_TARGET >= 40
    struct timeval tv_time;
#endif /* NS_TARGET */


    incr_cnt(sc->sc_if, if_ipackets);

    NB_GET_MARK(m,&flags);

    if (sc->sc_flags & SC_LOG_INPKT) {
	IOLog("ppp%d: got %d bytes\n", if_unit(sc->sc_if), NB_SIZE(m));
	pppdumpm(m);
    }

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

    if (flags & M_ERRMARK) {
	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){

	  NB_FREE(m);
	  if (dmp == NULL){
	    /* No error, but no decompressed packet returned */
	    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.
	     */
	    IOLogDbg("ppp%d: decompress failed %d\n", if_unit(sc->sc_if), 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 = NB_SIZE(m);

#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.
	 */

/*	IOLog("SC_VJ_RESET was set!\n"); */

	vj_uncompress_err(&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)
	    goto bad;


	xlen = vj_uncompress_tcp(cp + PPP_HDRLEN, ilen - PPP_HDRLEN,
				 ilen - PPP_HDRLEN,
				 &sc->sc_comp, &iphdr, &hlen);

	if (xlen <= 0) {
/*
   IOLogDbg("ppp%d: VJ uncompress failed on type comp\n", 
			if_unit(sc->sc_if));
*/
	    goto bad;
	}

	/*
	 * Write the IP/TCP header back into the datagram.
	 * The pointers point to the stored copy in the VJ
	 * compression table.
	 */
   
	NB_GROW_TOP(m, hlen - xlen);
	NB_WRITE(m, PPP_HDRLEN, hlen, iphdr);

	cp = mtod(m, u_char *);

#ifdef TCP_CHECKSUM
    {
#define getip_hl(base)	((base).ip_hl)

      u_short mytcpcksum (struct ip *pip);
      struct tcphdr *ptcp;
      struct ip *iphdr;
      u_short thecksum;
      u_long hlen;

      iphdr = (struct ip*) (cp + PPP_HDRLEN);
      hlen = getip_hl(*iphdr) << 2;  /* Length is in words */
      ptcp = (struct tcphdr *)&((u_char *)iphdr)[hlen];

      thecksum = (u_short)mytcpcksum(iphdr);

      if(ptcp->th_sum != thecksum)
	{
#ifdef NEWVJ_RESYNC
	  set_newvj_error_mode();
#endif
	  IOLog("NEWVJ: Warning... TCP checksum failed Received=%u, Calculated=%u)\n",
		(ptcp->th_sum)&0xffff, thecksum&0xffff);
	}
    }	    	    
#endif


	cp[0] = adrs;
	cp[1] = ctrl;
	cp[2] = 0;
	cp[3] = PPP_IP;
	proto = PPP_IP;

	ilen += hlen - xlen;

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


	vj_uncompress_uncomp(cp + PPP_HDRLEN, ilen-PPP_HDRLEN, &sc->sc_comp);

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


    rv = 0;
    switch (proto) {
#ifdef INET
    case PPP_IP:
	/*
	 * IP packet - take off the ppp header and pass it up to IP.
	 */
	if ((if_flags(sc->sc_if) & IFF_UP) == 0
	    || sc->sc_npmode[NP_IP] != NPMODE_PASS) {
	    /* interface is down - drop the packet. */
	    NB_FREE(m);
	    IOLogDbg("ppp%d: IP packed dropped (NPmode)\n", if_unit(sc->sc_if));
	    return;
	}
	NB_SHRINK_TOP(m, PPP_HDRLEN);
	inet_queue(sc->sc_if, NB_TO_nb(m));
#if NS_TARGET >= 40
	/*  I am assuming the time is different here than above. */
	ns_time_to_timeval(clock_value(System), &tv_time);
	sc->sc_last_recv = tv_time.tv_sec; /* update time of last pkt rcvd */
#else
	sc->sc_last_recv = time.tv_sec; /* update time of last pkt rcvd */
#endif
	return;
#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();
    if (nbq_full(inq)) {
	nbq_drop(inq);
	splx(s);
	IOLog("ppp%d: input queue full\n", if_unit(sc->sc_if));
	goto bad;
    }
    nbq_enqueue(inq, m);
    splx(s);

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

    return;

 bad:
    NB_FREE(m);
    incr_cnt(sc->sc_if, if_ierrors);
}

#define MAX_DUMP_BYTES	128

static void
pppdumpm(m0)
    NETBUF_T m0;
{
    char buf[3*MAX_DUMP_BYTES+4];
    char *bp = buf;
    static char digits[] = "0123456789abcdef";
    int l = NB_SIZE(m0);
    u_char *rptr = mtod(m0, 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];
    }

    *bp++ = ' ';
done:
    if (l)
	*bp++ = '>';
    *bp = 0;
    IOLog("%s\n", buf);
}